Technical field
[0001] The present invention relates to a method for controlling a heat pump laundry drying
machine, in particular including a drying cycle in which a relatively high temperature
of process air is achieved.
Background art
[0002] Heat pump dryer are widespread due to their drying efficiency.
[0003] However, heat pump laundry dryers are not generally designed to operate at such high
temperatures, that is, generally, heat pump laundry dryers operate at temperatures
of the process air, and thus reached by the laundry, below 50°C, which are commonly
considered high enough to dry standard clothes or textiles. If a heat pump laundry
dryer reaches temperatures above 50° - 55° C in the process air, it may happen that
safety measures activate which block or limit either the dryer functioning or further
raise in process air temperature.
[0004] For the purpose of the present disclosure, outdoor textiles have a waterproof and
breathable thin film material with a micro-porous structure.
[0005] Often, clothes designed and realized for outdoor conditions include a durable water
repellent (DWR), which is a coating added to fabrics at the factory to make them water-resistant
or hydrophobic. Most factory-applied treatments are fluoropolymer based. Durable water
repellents are commonly used in conjunction with waterproof breathable fabrics such
as Gore-Tex to prevent the outer layer of fabric from becoming saturated with water.
This saturation, called "wetting out", can reduce the garment's breathability (moisture
transport through the breathable membrane) and let water through. Methods for factory
application of DWR treatments involve for example applying a solution of a chemical
onto the surface of the fabric by spraying or dipping. More recently the chemistry
is applied in the vapor phase using Chemical Vapor Deposition (CVD) machinery.
[0006] This hydrophobic chemical treatment penetrates the fibres and lowers the surface
tension of the fabric, causing water to bead up and roll off the outer layer of fabric,
instead of being absorbed. The DWR treatment is not permanent: the surface coating
can degrade through regular wear and tear, exposure to dirt, detergent, insect repellent
and other impurities causing the outer fabric to absorb water. As the DWR wears off
over time, re-treatment is recommended when necessary. Certain types of fabrics need
to be re-treated to maintain water-repellency, as fluoropolymers decompose over time
when exposed to water and chemicals. As the garment becomes saturated with water,
the breathability decreases, as the absorbed water prevents water vapour (perspiration)
from passing from the inside to the outside of the garment creating a humid and wet
environment inside the garment. Another drawback is that a saturated fabric attracts
dirt particles, which clog the pores in the waterproof membrane, reducing breathability
even after the garment has dried.
[0007] Affected garments can be treated with a "spray-on" or "wash-in" treatment to improve
water-repellence. Heat treatment may reactivate the factory applied repellent finish
and aids the repelling of water, and other liquids such as oils.
[0008] In
EP2622120, a method for controlling drying machine is provided, which includes selecting and
starting an outdoor textiles drying procedure, and then entering a preheating stage,
a main drying stage, and a cooling stage. In the main drying stage, a working temperature
of the drying machine is lower than a working temperature of an ordinary drying procedure,
and after the cooling stage, nominal water content of loaded outdoor textiles is higher
than nominal water content after the ordinary drying procedure is performed. By setting
an appropriate drying working temperature, damages on material and sealing strips
at seams of the outdoor textiles during the drying procedure are prevented to the
greatest extent. Moreover, after the drying procedure is finished, nominal water content
of the outdoor textiles is higher than nominal water content of the other textiles
after the ordinary drying procedure is performed, which ensures that wrinkles caused
by over-drying do not occur to the outdoor textiles, and at the same time, the material
and sealing strips at the seams of the outdoor textiles are prevented from being damaged.
A drying machine having a control unit programmed for implementing the method is also
provided.
[0009] However, the disclosed treatment in a dryer does not provide the optimal solution
for re-activating, also called re-proofing, outdoor clothing and textile.
[0010] EP3124678 relates to method to operate a washing and/or drying appliance including a treating
chamber where items are introduced and treated with a process medium; a heat pump
system having a refrigerant circuit in which a refrigerant can flow, said refrigerant
circuit including a first heat exchanger where the refrigerant is cooled off, a second
heat exchanger where the refrigerant is heated up, a compressor to pressurize and
circulate the refrigerant through the refrigerant circuit, said compressor including
an electric motor, and a pressure-lowering device; said first and/or second heat exchanger
being apt to perform heat exchange between said refrigerant flowing in said refrigerant
circuit and said process medium; said method comprising: ¢ storing a plurality (j)
of data couples, a first element of each data couple being function of a maximum current
value i
MAXj for the compressor electric motor current, and the second element of the couple being
a corresponding function of a compressor maximum temperature value T
MAXj associated to the maximum current value i
MAXj of the first element, said plurality of data couples delimiting a safety work space
for said compressor; ¢ measuring substantially at the same time a temperature value
T
M representative of the temperature of said compressor and a current value i
M representative of the current absorbed by said electric motor of said compressor
while said heat pump is in operation; comparing said measured temperature value T
M and said measured current value i
M with said plurality of data couples; and cutting power supply to said compressor
if: there is a data couple (T
MAXj*, i
MAXj*) in said plurality for which |T
MAXj * - T
M| = min
j (|T
M - T
MAXj |) and i
M * i
MAXj* or there is a data couple (T
MAXj*, i
MAXj*) in said plurality for which | i
MAXj* - i
M| = min
j (| i
M - i
MAXj |) and T
M * T
MAXj *.
Summary of the invention
[0011] The present invention relates to a method for controlling a heat pump drying machine
where a relatively "high temperature" is preferred. The meaning of "high temperature"
is relative, that is, the method of the invention is preferably, but not necessarily,
used when a "higher than standard" temperature is required during a drying cycle.
As an example, the method of the invention could be used when an outdoor drying cycle
is provided, to re-activate (or "re-proof") the water repellent characteristics of
outdoor textiles, such as outdoor clothes and garments.
[0012] Applicant has indeed found that the outdoor textile, in order to have the surface
treatment "re-activated", needs a drying cycle, or drying cycle phase, having relatively
high temperature and low humidity, for example a temperature above 55°C and a humidity
below 5%.
[0013] Other drying program may need a temperature which is generally higher than the standard
temperatures used in heat pump dryer.
[0014] There is therefore the need for a method for which relatively high temperature can
be safely reached in a heat pump dryer.
[0015] According to an aspect, the invention relates to a method to operate a laundry drying
appliance including:
- a treating chamber where laundry is introduced and treated with process air;
- a heat pump system having a refrigerant circuit in which a refrigerant can flow, said
refrigerant circuit including a first heat exchanger where the refrigerant is cooled
off, a second heat exchanger where the refrigerant is heated up, a compressor to pressurize
and circulate the refrigerant through the refrigerant circuit, and a pressure-lowering
device; said first and/or second heat exchanger being apt to perform heat exchange
between said refrigerant flowing in said refrigerant circuit and said process air;
- a selector adapted to select alternatively one of a plurality of drying programs,
each drying program including a main drying phase;
said method comprising:
- setting a first limit temperature value representative of the limit temperature of
the compressor;
- setting a second limit temperature value representative of the limit temperature of
the compressor;
- selecting a drying program among the plurality and starting its drying phase;
- sensing an operating parameter representative of the humidity of the laundry in the
treating chamber;
- measuring a temperature value representative of the temperature of said compressor;
- selecting the first limit temperature value for a first plurality of values of the
sensed operating parameter representative of the humidity of the laundry during the
drying phase;
- selecting the second limit temperature value for a second plurality of values of the
sensed operating parameter representative of the humidity of the laundry during the
drying phase; and
- limiting power supply to or switching off said compressor if the measured temperature
value is higher than the first or the second limit temperature value, depending on
which one is selected when the measured temperature value exceeds the limit temperature
value.
[0016] The laundry drying machine or appliance of the invention may be preferably a laundry
dryer or a laundry washer dryer.
[0017] A heat pump laundry drying machine includes a rotatable treating chamber, such as
a drum, in which the load of laundry, e.g., clothes, or other items to be washed and/or
dried are placed. The laundry is made of a given textile. The treating chamber is
adapted to rotate in a direction and in an opposite direction, reversing its rotation,
for example driven by a motor, such as a variable speed motor in order to regulate
the speed of rotation of the treating chamber.
[0018] The treating chamber is part of a process circuit, in particular for example a closed-loop
air circuit in case of a condensed dryer or an open air circuit in case of a vented
dryer, which in both cases includes an air duct for channelling a stream of process
air to dry the load. The process air circuit is connected with its two opposite ends
to the drum. For example, in case of a dryer, hot dehumidified air is fed into the
drum, flowing over the laundry, and the resulting humid cool air exits the same. The
humid air stream rich in water vapour is then fed into an evaporator of a heat pump,
where the moist warm process air is cooled and the humidity present therein condenses.
The resulting cool dehumidified air is then either vented outside the appliance in
the environment where the latter is located or it continues in the closed-loop circuit.
In this second case, the dehumidified air in the process air circuit is then heated
up before entering again in the drum by means of a condenser of the heat pump, and
the whole loop is repeated till the end of the drying cycle. Alternatively, environment
air enters into the drum from the environment via an inlet duct and it is heated up
by the condenser of the heat pump before entering the drum. The process air is preferably
blown within the process air circuit by means of a process air fan for example a variable
speed fan, driven by a motor. Preferably, the motor of the fan and the motor of the
treating chamber are the same motor. Different circuits are known in the art in case
of a washer-dryer.
[0019] The heat pump of the drying machine includes a refrigerant circuit in which a refrigerant
can flow and which connects via piping a first heat exchanger or condenser, a second
heat exchanger or evaporator, a compressor and a pressure-lowering device. The refrigerant
is pressurized and circulated through the system by the compressor. On the discharge
side of the compressor, the hot and highly pressurized vapour is cooled in the first
heat exchanger, called the condenser, until it condenses into a high pressure, moderate
temperature liquid, heating up the process air before the latter is introduced into
the drying chamber. The condensed refrigerant then passes through the pressure-lowering
device such as an expansion device, e.g., a choke, a valve or a capillary tube. The
low pressure liquid refrigerant then enters the second heat exchanger, the evaporator,
in which the fluid absorbs heat and evaporates due to the heat exchange with the warm
process air exiting the drum. The refrigerant then returns to the compressor and the
cycle is repeated.
[0020] In order to compress the refrigerant, the compressor preferably includes an electric
motor which is commonly powered by a current, for example a current coming from the
mains.
[0021] The drying machine of the invention preferably includes a selector, for example operable
by the user, with which a plurality of drying cycles can be alternatively selected.
A drying machine generally includes a plurality of drying cycles each designed to
treat laundry made of a specific textile type or composition, such as a cotton cycle
at high temperature for cotton textile; permanent press, which generally refers to
coloured garments and utilizes medium heat; a knits/delicate cycle is for delicate
textiles which cannot withstand very much heat; the delicate cycle uses air slightly
above room temperature to gently and slowly dry fragile garments, etc. Therefore,
generally the cycle is selected depending on the type of textile to be dried. Among
the cycles which can be selected by the selector of the drying machine, the drying
machine of the invention includes an outdoor cycle to properly dry outdoor textiles
and re-activate - at least partially - their waterproof and/or water repellent qualities.
[0022] Many different types of drying cycles can be present in the drying machine of the
invention or only two different cycles.
[0023] Each cycle can differ from the other cycles by a plurality of different settings,
such for example the temperature of the process air which flows inside the drum to
dry the textile, the time duration of the cycle, the speed of revolution of the drum,
the number of changes in direction of revolution of the drum, the degree of humidity
at which the textile is considered to be dry and the cycle terminated, etc. All these
settings and the corresponding program lines for each cycle are for example included
in a memory of the drying machine, for example in a main controller circuit of the
drying machine. Further, each cycle, although preferably not visible to the user,
may include one or more settings for the heat pump operation.
[0024] Each drying cycle includes a main drying phase, which is the phase in which the clothes
and/or textile introduced in the drum are dried. Each cycle may include also other
phases, such as a cooling phase after the main drying phase, in which the laundry
is cooled before the user may access them. In the cooling phase, the temperature reached
by the textile in the main drying cycle is reduced. Further, one or more of the drying
cycles may include a pre-heating phase where the drum and other components of the
drying machine are heated up in order to pre-warm the machine so that it reaches the
optimal temperature to start the main drying phase.
[0025] The selection of a laundry drying cycle or program can be made in any possible way,
for example by means of a mechanical switch or a rotatable knob, by means of buttons,
one per cycle, by means of a touch screen, etc. Further, the selection can be performed
by the user manually, by means of a remote control or by means of a wireless command
signal, automatically due to a pre-set timer, etc.
[0026] The selection of the cycle preferably depends on the type of clothes, garment, textiles,
etc. inserted in the drum.
[0027] Once the selection of the drying cycle is performed, the drying cycle starts.
[0028] In a heat pump laundry drying machine, the laundry is dried at a relatively low temperature,
e.g. the temperature of the textile present in the drum commonly does not exceed 50°C-55°C.
According to the method of the invention, in order to raise the temperature of the
textile in the drum, for example above 50°C, the temperature of the compressor is
monitored.
[0029] It is known in the art that a compressor of a heat pump, such as the heat pump present
in laundry washing and/or drying appliances, can work under safety condition if it
works within a field of temperature values. These values may follow a given curve,
which depends on the type of compressor. Each compressor has its own specific curve
delimiting its own safety working area which depends on the characteristics of the
compressor itself.
[0030] In an embodiment, the compressor, in order to work in safety conditions, should not
overheat, that is, there is a field of working conditions, function of the temperature
of the compressor and of the absorbed current of the electric motor of the compressor,
in which the compressor can work without overheating. The field of safe working conditions
for the compressor is generally delimited by a compressor curve.
[0031] Therefore, preferably, there is a "limit temperature" above which the compressor
is preferably not allowed to work. This limit temperature may depend on several parameters,
not only on the type of compressor. For example, it may depend on the environment
temperature surrounding the laundry.
[0032] Preferably, for example, the limit temperature of the compressor is sensed anywhere
in the refrigerant circuit.
[0033] Commonly, also a "over safe" area around the safe working range is present, that
is, in order to increase the safety, a lower temperature or lower current than the
one at the boundary of the real safe working range is considered as a limit temperature
for the compressor, above which the compressor is preferably switched off or the power
applied to the compressor should be limited.
[0034] In order to always work within the safety field of the compressor, safety precautions
may be taken in the laundry dryer. For example, the requirement of working in such
a safe field or working area is generally assured by the presence of a passive switch
which interrupts the power supply to the heat pump compressor when predetermined thresholds
of heat or current (or voltage load) are exceeded. The passive switch - called OLP
- opens when a threshold temperature of the heat pump compressor is reached or when
a power load or current through the passive switch is reached, because also in this
case a high current causes the bimetallic switch to overheat and reach the switching
temperature.
[0035] Alternatively or in addition to the OLP, the limit temperature may be set via software,
that is, as soon as the temperature of the compressor reaches a given limit value,
the compressor is not allowed to work.
[0036] Alternatively or in addition, the limit temperature may be set with reference to
another variable. For example, the limit temperature may depend on the temperature
at which a fan cooling the compressor starts blowing.
[0037] Both OLP limit temperature and software limit temperature may be present as well,
for example, the software limit temperature for example may be lower than the OLP
temperature for a higher security margin.
[0038] The limit temperature for the compressor may be set also in other ways.
[0039] If this limit temperature is reached, regardless on how the limit temperature is
set, the compressor is either switched off or the power supplied to the compressor,
for example the current supplied to the compressor motor, is limited. The power could
be for example lowered, or interrupted for a time interval.
[0040] According to the invention, a first limit temperature and a second limit temperature
are set, in any manner known in the art, for example according to one of the above
embodiments.
[0041] Preferably, the first limit temperature is different from the second limit temperature.
[0042] The difference between the first and the second limit temperature may be cycle dependent,
that is, it may vary depending on the drying cycle or program which has been selected.
Further, it may depend on the type of compressor, on the type of dryer, on the amount
of laundry to be dried, on the external temperature, conducibility value of water
(for example set by the user), etc.
[0043] Further, also the value of the first and second limit temperature may depend on the
variables above listed with reference to the difference between the first and the
second limit temperature.
[0044] Just as an example, in all drying cycle, the temperature of the drying machine or
appliance at the beginning of the drying cycle is sensed. This temperature is the
temperature of the surrounding to the machine, that is, it is an "environment" temperature.
The first and second limit temperature may vary depending on this initial temperature
of the dryer. For example, as a first or second limit temperature, the temperature
at which a fan cooling the compressor is activated is chosen, plus a given constant.
Therefore, in an embodiment:
[0045] The constant temperature chosen can be not only 5°C, but any, and it may vary depending
on the selected drying cycle.
[0046] In the following, the first limit temperature values are given as examples for different
drying cycles:
Cotton cycle:
T1 limit temperature=95°C, if temperature at the beginning of the cycle is "cool", or
normal, that is, if the temperature is below or equal27°C.
T1 limit temperature=90°C, if temperature at the beginning of the cycle is "warm", that
is, if the temperature is above 27°C. ool cycle:
T1 limit temperature=85°C, if temperature at the beginning of the cycle is "cool", or
normal, that is, if the temperature is below or equal 27°C.
T1 limit temperature=75°C, if temperature at the beginning of the cycle is "warm", that
is, if the temperature is above 27°C.
Outdoor cycle:
T1 limit temperature=100°C, if temperature at the beginning of the cycle is "cool",
or normal, that is, if the temperature is below or equal 27°C.
T1 limit temperature=90°C, if temperature at the beginning of the cycle is "warm", that
is, if the temperature is above 27°C.
[0047] The second temperature limit is set higher than the first temperature limit (T
1 limit temperature) in all the above examples. For example, the second temperature
limit is set equal to
or
or
[0048] Most preferably,
[0049] The first temperature is applicable in a first condition of the laundry dryer and
the second temperature is applicable in a second condition of the laundry dryer.
[0050] The first and second conditions are defined by a humidity value of the laundry. That
is, the first limit temperature is selected, that is, is applicable, when the humidity
of the laundry has a value among a first set of humidity values. Likewise, the second
limit temperature is selected when the humidity of the laundry has a value among a
second set of humidity values.
[0051] Preferably, the first and second set are distinct set, that is, the first and second
set do not overlap. Therefore, if the humidity of the laundry belongs to the first
set, then the first limit temperature is selected, if the humidity of the laundry
belongs to the second set, then the second limit temperature is selected.
[0052] It is thus clear that the limit temperature may vary during the drying cycle, because
the humidity of the laundry changes during the cycle. At the beginning of the drying
cycle, the humidity of the laundry is rather high, while towards the end of the drying
cycle, the humidity of the drying cycle is rather low. Therefore, for a time interval
of the drying cycle, the set limit temperature may be the first one, while for another
time interval, the set limit temperature for the compressor may be the second one.
[0053] Among the plurality, there might be drying programs for which the compressor limit
temperature does not vary, that is, regardless of the value of the humidity the compressor
limit temperature remains always the same, for example equal to either the first or
the second limit temperature. However, the change in limit temperature of the compressor
takes place at least for one program among the plurality.
[0054] According to the invention, two values are monitored during the drying cycle. A first
value is relative to the humidity of the laundry. The humidity of the laundry may
be sensed in many different ways. Any known method or sensor may be used. Each of
these methods or sensors outputs a value which depends on the humidity of the laundry
and may be translated in a humidity value. This humidity value may be a continuous
value, that is, it may be an "analogic" value, or a step-like value, so that only
a plurality of values is admitted.
[0055] Further, also the temperature of the compressor is monitored. Also in this case,
any method or sensor used to monitor the temperature of the compressor can be used.
[0056] The limit temperature of the compressor is selected depending on the output of the
humidity sensor. Thus, at any point in time during the drying cycle, the first or
the second limit value of the temperature of the compressor may be selected.
[0057] The temperature of the compressor is monitored preferably during the whole drying
cycle. A value indicative of this temperature is detected. If this temperature is
too high, that is, it is higher than the first limit value if the first limit value
has been selected, or it is higher than the second limit value, if the second limit
value has been selected, then the compressor is either switched off, or the power
supplied to the compressor is limited. For example, it is reduced.
[0058] The decision whether the power is reduced or cut off completely depends, among others,
on the choice of a predetermined safe field are aof working for the compressor, which
in turn imply the choice of the limit temperature for the compressor. In case for
example the limit temperature coincides with the real boundary for a safe functioning
of the compressor, when such a safety field is exceeded, it is preferred to cut the
power supply completely (that is, the compressor is switched off). Alternatively,
in a case where although the limit temperature is exceeded by the measured value,
the real safety field probably is not exceeded yet, thus the power to the compressor
could be reduced, because there is a "buffer" of safety field area before reaching
the real boundary of the safety field of the compressor.
[0059] Otherwise, if the temperature of the compressor stays below the first or the second
limit temperatures, the selected drying cycle continues as programmed.
[0060] In this way, the limit temperature during the drying cycle can be varied. The variation
depends on the humidity value of the laundry.
[0061] This variation may help, among others, to raise the temperature inside the drum.
An increase of temperature inside the drum may be achieved if first the water in the
outdoor textile is preferably evaporated so that the heat provided by means of the
heated process air can be used to increase the temperature of the laundry and not
only to evaporate the water contained therein. It is known that the latent heat of
water is relatively high and a substantial temperature increase can take place only
when the phase change from liquid to vapour is preferably substantially over.
[0062] Thus preferably the change in limit temperature, for example from a lower first limit
temperature to a higher second limit temperature, the humidity of the laundry should
be relatively low.
[0063] Preferably, the invention, according to the above mentioned aspect, includes in combination
or alternatively, one or more of the following characteristics.
[0064] Preferably, the step of limiting power supply to or switching off said compressor
if the measured temperature value is higher than the first or second limit temperature
value includes limiting power supply to or switching off said compressor if any of
the following takes place:
- the measured temperature remains above the first or second limit temperature value
for a time interval longer than a time threshold;
- the measured temperature reaches or exceeds the first or second limit temperature
value for a number of times above a number of times threshold;
- the difference between the measured temperature and the first or second limit temperature
value exceeds a temperature difference threshold.
[0065] Preferably, the compressor is not switched off, or the power is not limited, immediately
after a first data of the temperature value of the compressor above the first or second
limiting value has been retrieved. Indeed, an occasional high temperature value might
be due to an error in the measurement or to a transient event. Therefore, the switching
off or power limitation takes place only when a "reasonably correct" over-temperature
is detected. The chances of an error may be limited if the temperature is above the
limit temperature for a given "long" time interval, or if the temperature becomes
higher than the limit temperature several times, or if the measured temperature far
exceed the limit temperature. A combination of the above can be used as well.
[0066] Preferably, sensing an operating parameter representative of the humidity of the
laundry in the treating chamber includes one or more of:
- sensing an electrical conductivity of laundry within the treating chamber;
- sensing a capacitance of a volume comprising the laundry;
- measuring a value representative to a torque of a motor rotating the treating chamber;
- measuring a temperature of the process air leaving the treating chamber;
- measuring a temperature difference between a temperature of the process air entering
the process chamber and a temperature of the process air leaving the chamber.
[0067] The humidity of the laundry present inside the drum can be detected using one (or
more) of a plurality of different sensors. A combination of signals provided by different
sensors can be used as well. The signal can be a direct humidity signal, for example
coming from a sensor measuring a resistance of the laundry which is contacting one
or more electrodes located within the drum. A higher degree of dryness corresponds
to a higher electrical resistance. Alternatively or in addition, the temperature of
the process air, either at the inlet or at the outlet of the drum, may give an indication
of the degree of dryness of the laundry. Further, the temperature of the process air
can also be measured at the exit of one of the heat exchanger of the heat pump. The
temperature of the refrigerant might also give an indication of the humidity of the
laundry in the drum. Further, measuring the level of water in a container where the
condense water collects, or the temporal gradient of a level of water removed from
the container, may also indicate whether the laundry is dry or not: if for example
the level of water does not increase for a given time interval, reasonably it means
that there is no more water to be removed from the textile in the drum and that the
textile is thus substantially dry. The number of activations of a pump driving water
removed from the textile contained in the drum to a container, may also be representative
of the laundry humidity status within the drum. Further, one or more electrical parameters
of the drum motor may also indicate the level of humidity of the textile, such as
for example the absorbed power. The textile is heavier when water is contained therein
and becomes lighter the dryer it is.
[0068] Preferably, said compressor includes a casing and an oil circuit in which oil flows,
and wherein measuring a temperature value representative of the temperature of said
compressor includes one or more of:
- measuring a temperature of said compressor casing;
- measuring a temperature of the refrigerant;
- measuring a temperature of the oil.
[0069] Several ways to measure the temperature of the compressor are possible as well. A
"direct" measurement can be made for example measuring the temperature of the casing
of the compressor. A more indirect measurement can be made measuring the temperature
of the oil and/or of the refrigerant in the oil or refrigerant conduit, from which
the temperature of the compressor can be evaluated.
[0070] Preferably, selecting the first limit temperature value includes selecting the first
limit temperature value when the humidity of the laundry is below a first humidity
threshold. Preferably, selecting the second limit temperature value includes selecting
the second limit temperature value when the humidity of the laundry is above a second
humidity threshold. More preferably, said first humidity threshold is equal to the
second humidity threshold. Therefore, according to an embodiment, the first limit
temperature is selected when the humidity of the laundry is below a certain threshold.
That is to say, for "dry" laundry, the first limit temperature is selected. On the
other hand, for "wet" laundry, that is, for humidity above another or the same threshold,
the second limit temperature is selected.
[0071] Preferably the first limit temperature is higher than the second limit temperature.
Thus, when the laundry is relatively dry, it is allowed to increase the limit temperature
of the compressor, so that a higher temperature can be reached in the drum.
[0072] Preferably, the method includes the step of setting the first or second humidity
threshold, the setting of the first or second humidity threshold being based on one
or more of:
- the selected drying program;
- a weight of the laundry;
- a laundry fabric type or composition;
- duration of the selected drying program;
- an electrical parameter supplied to a motor rotating the treating chamber.
[0073] The first or second humidity threshold may be dependent on a plurality of parameters.
Therefore, they might also differ depending on the selected drying program. Indeed,
depending on the weight or on the type of textile, high temperatures could be reached
with dryer or wetter laundry. Further, in short drying program a "very dry" laundry
might not be obtained and therefore the threshold on humidity might be higher.
[0074] Preferably, the first or second humidity threshold is indicative of a humidity value
of the laundry of about 1% or less. More preferably, the first limit temperature is
used for laundry dryer than this threshold (i.e. humidity lower than 1%), while for
wetter laundry, i.e. for laundry having a humidity higher than this threshold, the
second limit temperature is used.
[0075] Preferably, the method includes:
- sensing a temperature of an environment external to said laundry drying appliance;
and
- wherein the first or second limit temperature value is a function of said environment
temperature.
[0076] The environment temperature may affect the functioning of the heat pump. Indeed,
in hot external conditions, the compressor is already slightly overheated and it is
more difficult to keep it cool. Thus, the limit temperature for example in hot external
temperature may be lower than the limit temperature in standard or cool external conditions.
[0077] Preferably, said laundry appliance includes a fan adapted to blow air towards said
compressor to cool the same and wherein selecting the first limit temperature value
for a first plurality of values of the sensed operating parameter representative of
the humidity of the laundry during the drying phase; or selecting the second limit
temperature value for a second plurality of values of the sensed operating parameter
representative of the humidity of the laundry during the drying phase, includes selecting
a first or second temperature threshold, respectively, provided to
- activate and /or deactivate said fan;
- modify the airflow supplied by said fan.
[0078] A cooling fan unit or blower unit may be arranged close to the compressor to remove
heat from the compressor, i.e. from the heat pump system, during a drying operation.
The cooling air flow, which is an environment air flow in the embodiments, is actively
driven by the cooling fan unit and is taking heat from the compressor. The fan unit
comprises a blower or fan which is for example driven by a fan motor controlled by
a control unit of the dryer. By transferring heat from the compressor, during a steady
state of operation of the heat pump system, thermodynamic balance is achieved between
the closed loops of the process air loop and refrigerant loop. Thereby the electrical
power consumed by the compressor and which is not transformed to work power by compressing
the refrigerant, is removed from the heat pump system, i.e. heat power of o the compressor
is balanced in the - under ideal consideration - closed loops of refrigerant and process
air. This means, in the steady state of the heat pump system in which maximum or nearly
maximum operation condition or efficiency is achieved after the warm-up period, the
heat deposited by the compressor in the refrigerant loop is balanced by the cooling
fan unit to prevent overheating.
[0079] The fan of the compressor starts blowing air when a given temperature of the compressor
is reached. Selecting a first limit temperature of the compressor and a second limit
temperature of the compressor in a preferred embodiment also includes selecting a
first and a second temperature at which the fan starts blowing air towards the compressor
(or stops blowing air toward the compressor). Alternatively, a first and a second
temperature may be selected at which the fan changes the airflow supplied towards
the compressor (for example, providing more or less air). Thus the activation/deactivation
temperature of the fan or the change-airflow temperature of the fan of the compressor
may vary depending on whether the first or the second limit temperature has been selected.
[0080] Preferably, said plurality of drying programs includes an outdoor drying program
for drying outdoor textiles which have a waterproof and breathable thin film material
with a micro-porous structure, and at least an additional drying program for drying
other types of textiles, wherein the outdoor drying program includes an outdoor drying
phase having settings for a frequency of reversion of rotations of the drum and for
the heat pump operation and the additional drying program comprises an additional
drying phase having settings for a frequency of reversion of rotations of the drum
and for the heat pump operation; and wherein:
- selecting a drying program among the plurality and starting its drying phase includes
selecting the outdoor drying program; and
- reversing the rotation of the treating chamber in the outdoor drying program at a
frequency lower than a frequency in the additional main drying phase at least for
a portion of the drying phase.
[0081] Outdoor clothes or garments are herewith considered as those clothes which include
a water repellent layer and/or a waterproof film or layer. Both waterproof and water
repellent layers can be present in the same garment.
[0082] It is preferred to achieve a high enough temperature in the drum, that is, a temperature
which has been found to be optimal for "proofing", that is, for re-activating at least
partially the waterproof and/or water repellent layer of the outdoor textile. In order
to reach a relatively high temperature in the outdoor first sub-phase, preferably
the frequency of reversing the rotation of the drum is set lower than a frequency
of reversing the rotation in the additional main drying phase.
[0083] Indeed, when rotation of the drum is reversed, a deceleration and a stop of the drum
itself take place. Since a process air fan is generally driven by the same motor that
drives the drum into rotation, these deceleration and interruption of motion consequently
reduce the amount of process air flowing in the drum, lowering the temperature. For
this reason, the number of reversions may influence the temperature of the textile
present inside the drum. Keeping the number of reversions low, that is, lower than
in the additional drying cycle present in the laundry dryer, may help to increase
the overall temperature of the outdoor textile contained in the drum.
[0084] More preferably, the outdoor drying program includes a first drying sub-phase and
a second-drying sub-phase, wherein:
- in the second drying sub-phase, reversing the rotation of the drum at a frequency
lower than the drum rotation reversal frequency operated in the outdoor first sub-phase;
and
- in the second drying sub-phase, selecting the first limit temperature of the compressor.
[0085] As mentioned, in a heat pump laundry drying machine, the laundry is dried at a relatively
low temperature, e.g. the temperature of the textile present in the drum commonly
does not exceed 50°C - 55°C. According to the method of the invention, in order to
raise the temperature of the textile to a temperature which has been found to be optimal
for "proofing", that is, for re-activating at least partially the waterproof and/or
water repellent layer of the outdoor textile, first the water in the outdoor textile
is preferably evaporated so that the heat provided by means of the heated process
air can be used to increase the temperature of the outdoor textile and not only to
evaporate the water contained therein. It is known that the latent heat of water is
relatively high and a substantial temperature increase can take place only when the
phase change from liquid to vapour is preferably substantially over.
[0086] Thus the outdoor first sub-phase is a phase of drying the outdoor textile till a
first threshold of humidity, below which the "proofing" phase starts, which is the
outdoor second sub-phase. In order to reach a relatively high temperature in the outdoor
first sub-phase, preferably the frequency of reversing the rotation of the drum is
set lower than a frequency of reversing the rotation in the additional main drying
phase.
[0087] Keeping the number of reversions low, that is, lower than in the additional drying
cycle present in the laundry dryer, may help to increase the overall temperature of
the outdoor textile contained in the drum.
[0088] Further, when the humidity in the laundry is equal or below the first threshold,
the outdoor second sub-phase starts. At the same time, the first limit temperature
is selected, being the threshold for the beginning of the second sub-phase and for
the selection of the first limit temperature the same.
[0089] In the second sub-phase, the heat introduced by process air is not only transformed
in latent heat but may further increase the temperature of the textile itself. In
order to reach a relatively high temperature for a heat pump dryer, that is, in order
to reach a temperature preferably above 59°C in the outdoor second sub-phase, the
air flow in the drum is to be "limited", that is, the air flow is reduced, when compared
to the air flow present in the first sub-phase of the outdoor cycle or when compared
to the airflow present in the additional main drying phase. A reduction in air flow
allows a further heating up of the laundry present inside the drum, therefore achieving
a "proofing phase" for the outdoor garments.
[0090] Preferably, said outdoor drying program includes a first drying sub-phase and a second-drying
sub-phase, and wherein:
- in the outdoor second drying sub-phase, increasing a flow rate of the process air
in the treating chamber with respect to a flow rate in the outdoor first drying sub-phase
and with respect to a flow rate in the additional drying phase.
[0091] The comparison between flow rates is performed in the whole sub-phase, that is, the
mean flow rate in the first second sub-phase per time unit should be compared with
the mean flow rate of the first sub-phase per time unit or the mean flow rate in the
additional main drying cycle per time unit. Indeed, there can be time interval(s)
in the first sub-phase or in additional drying cycle in which the flow rate is at
that instant lower than the flow rate in another different instant in the second sub-phase,
for example when the fan in the first sub-phase or additional cycle is not rotating.
[0092] Therefore, the "mean" in the whole sub-phase, divided by the time of duration, should
be compared.
[0093] Preferably, the laundry drying appliance includes an overload protector adapted to
cut power to said compressor, said overload protector defining a tripping temperature,
and wherein setting a first limit temperature value or setting a second limit temperature
value representative of the limit temperature of the compressor includes setting a
first or second limit temperature value lower than the tripping temperature of the
overload protector.
[0094] In an embodiment, the laundry appliance of the invention includes an OLP. In the
invention, the setting of a first sand second temperature, preferably lower than the
OLP tripping temperature, prevents the OLP from tripping because the method interrupts
or limit the flow of current to the compressor electric motor even before the activation
of the OLP, that is, as soon as the temperature of the compressor gets higher than
the first or second limit temperature, both lower than the tripping temperature of
the OLP. In this way, the compressor can be cooled and restarted in a much quicker
way than in cases in which the OLP interrupts the current flows. Further, in case
the laundry appliance includes an OLP, the method and appliance of the invention act
as a "double security", so that in case of a double failure of two components in a
control circuit in the laundry appliance, the compressor still will not overheat,
being shut down or having a more limited power either by the OLP or by the control
of the invention.
[0095] On the other hand, also when the OLP is not present, the control of the invention
forces the compressor to work always in the predetermined safety field of operation,
because otherwise - outside such a field - the current to the compressor is cut off
or reduced.
[0096] It is to be understood that the inclusion of an OLP is only one of the possible embodiments
of the invention. The laundry appliance of the invention and/or operating according
to the method of the invention could also be "OLP-free", that is the control of the
invention allows removing the OLP from the laundry appliance and at the same time
to guaranteeing the same safety level.
Brief description of the drawings
[0097] Reference is made in detail to preferred embodiments of the invention, examples of
which are illustrated in the accompanying figures, where:
- Fig. 1 is a perspective view of a drying machine according to the invention,
- Fig. 2 is a schematic overview of some components of the drying machine of Fig. 1,
- Fig. 3 is a block diagram depicting some of the components of the drying machine of
Fig. 1 providing signals to a control unit and/or being controlled by the control
unit,
- Fig. 4 is a plurality of graphs showing the temporal behaviour of several parameters
of the drying machine of the invention during the outdoor drying cycle, and
- Fig. 5 is a flow chart of the method of the invention.
[0098] Fig. 1 shows a perspective outer appearance of an exemplary laundry drying machine
2. In this embodiment, the laundry drying machine is a laundry dryer only, but in
alternative embodiments the dryer function according to the control method is implemented
by a laundry washer-dryer in which the rotatable drum is arranged in a tub and which
provides a washing arrangement including (for example) a detergent dispenser, a heater
for heating wash liquid and a drain pump for draining out of the liquids.
[0099] As shown in Fig. 1, the laundry drying machine 2 has an outer housing 4 or cabinet
including a front wall 6. Further, the laundry drying machine 2 includes a drum 16,
also named treating chamber, where the laundry is positioned in order to be dried.
At the front wall 6 a loading opening 8 is provided which is closed by a door 10,
to access the drum 16. In the depicted embodiment, the laundry dryer is a front-loading
laundry dryer having a horizontal drum rotation axis, but in alternative embodiments
the drum may be inclined relative to the horizontal and vertical directions, or the
dryer may be a vertical rotation axis dryer in which the drum rotates around a vertical
axis and where top-loading is provided.
[0100] The laundry drying machine 2 has a control panel 12 arranged at the upper region
of the front wall 6 and a condensate drawer 14 in which the condensate collected from
drying is stored until removal by the user.
[0101] In the schematic diagram of components shown in Fig. 2, the drum 16 is arranged inside
the housing 4, in which laundry 18 is received. The flow of process drying air A is
indicated by the arrows, wherein the drying air A leaves the drum 16 at an outlet
24 and enters a process air channel 20 at the front channel 20c. By the front channel
20c the process drying air is guided through a fluff filter element 26 towards a second
heat exchanger 34 and a first heat exchanger 32. The first and second heat exchangers
32, 34 are arranged in a battery channel 20a of the process air channel 20. The first
heat exchanger 32 is a condenser which heats the process drying air and the second
heat exchanger 34 is an evaporator which cools the process drying air for humidity
removal in form of condensed water.
[0102] The process drying air leaving the first heat exchanger 32 is entering a rear channel
20b in which a drying process air fan 28 is arranged which conveys the drying air.
The process air fan 28 is driven by a motor 30, which preferably at same time drives
the rotation of the drum 16. However two different motors can be provided as well.
The rotation of the drum 16 can be in one direction and also in the opposite direction,
that is, reversing the rotation of the drum is possible in the laundry dryer operation,
by opportunely driving the drum driving motor. In the depicted embodiment, a belt
driven by the motor 30 is wound around the drum mantel for driving the fan. In the
depicted embodiment, in which the single motor 30 drives the process air fan 28 as
well as the drum 16, the drum and process air fan 28 are driven in a synchronous manner
according to the gear ratio. Preferably, the speed of the drum and/or the process
air fan is adjustable. Synchronous rotation of the drum includes a forward and backward
rotation according to the motor forward and backward rotation, so that the direction
of rotation of the drum can also be changed, from a forward to a backward or vice
versa. As an example, the fan speed is identical to the motor speed as the process
air fan is arranged on an axis of the motor 30, while via the belt the rotation of
the motor is gear-reduced in an exemplary ratio of motor rotation speed/drum rotation
speed of 50:1.
[0103] The first and second heat exchangers 32, 34 are part of a heat pump system 44 which
further comprises an expansion device 38 and a compressor 36. In the heat pump system
44 a refrigerant loop 40 is formed, wherein the refrigerant pumped by the compressor
36 passes first the condenser 32, is forwarded to the expansion device 38 from where
it expands into the second heat exchanger 34 and from where it is sucked into the
compressor 36. Heat can be removed from the heat pump system (in addition to the heat
deposited in the drying air and laundry for drying the laundry) by activating a compressor
cooling fan 42 which provides a flow of cooling air from the outside of the cabinet
4 towards the outer surfaces of the compressor 36. The compressor cooling fan can
be activated, that is, it can start blowing air against the compressor, for example
above a given compressor temperature, and/or it may be deactivated, that is, it may
stop blowing air against the compressor, for example below a given compressor temperature.
In addition, the flow rate of the air moved by the compressor cooling fan 42 may be
varied as well. After passing the compressor 36, the cooling air blown by the compressor
cooling fan 42 is exhausted out of the cabinet 4.
[0104] The condensate that is formed at the evaporator 34 flows down and collects in a condensate
collector 48. From the condensate collector 48 the condensate is pumped by a draining
pump 50 through a drain conduit 52 into the condensate drawer 14 from where it can
be removed by the user as mentioned above. Preferably, in the condensate collector
48, the level of water can be measured by means of a level sensor and/or the temporal
gradient of a level of water removed from the outdoor textile to be dried and collected
can be measured as well.
[0105] One or more of the following can be present in the laundry dryer as well: at the
outlet 24 of the drum 16 a temperature sensor, for example a thermocouple, is provided
which detects the outlet temperature To of the drying air. At the inlet 22 of the
drum 16 another temperature sensor, for example a thermocouple, is provided which
detects the inlet temperature Ti of the drying air. At the outlet of the condenser
32 a temperature sensor is provided which detects the refrigerant temperature Tr at
this position. Inside the drum, electrodes may be present as well to determine the
degree of humidity Hum of the laundry when it contacts the electrodes, for example
by means of a resistivity measurement. Further, an environment temperature Tamb, that
is, a temperature of the external surrounding of the laundry dryer is detected as
well, by an additional sensor.
[0106] Fig. 3 is a block diagram of components of the dryer 2 that interact for enabling
a control unit 60 to control the drying operations or programs. The control unit 60
has a memory 62 in which program parameters and look-up tables are stored such that
the control unit, by retrieving corresponding data from the memory 62, can control
different basic drying programs preferably under conditions as set by the user via
option selectors at the control panel 12. The user can select a program cycle among
a list of different program cycles. The selection can be performed by means of a selector
(not shown in the drawings and standard per se) in the panel 12. Such user-settable
options are for example: the type of drying cycle (cotton, delicate, outdoor, etc.),
the final drying degree, the load of the laundry loaded by the user and inputted by
him/her, the type of laundry, the duration of drying, an energy option, etc.
[0107] Among the cycles, an outdoor cycle is included, which is preferably selected when
outdoor textile is introduced in the laundry 16.
[0108] Preferably, each cycle includes a main drying phase and a subsequent cooling phase.
A pre-heating phase may be optionally included as well.
[0109] With now reference to figure 5, the dryer 2 is switched on in step S0 and a drying
cycle is selected among those selectable by the selector S1.
[0110] In any selected drying cycle, the control unit 60 sends control signals to a drum
motor inverter 64 and may receive operation parameters therefrom. The drum motor inverter
64 supplies the power to the motor 30 driving the drum 16 and the drying air fan 28.
The control unit 60 may send control signals to a compressor motor inverter 66 and
may receive operation parameters therefrom. The inverter 66 powers a compressor motor
67 for driving the compressor 36. Further, the control unit 60 may control the draining
pump 50, a motor 68 for driving the compressor cooling air fan 42 and optionally,
if a separate motor 70 is provided for the drying air fan 28, the drying air fan motor
70. The command signals sent by the control unit 60 depend on the specific settings
of the specific program (drying cycle) selected.
[0111] For example, an outdoor program may be selected. However, the following applies to
any drying program. Further, there might be programs for which the limit temperature
of the compressor does not change with humidity. These programs are not described
in the following.
[0112] The settings of the main drying cycle of the selected programs are stored in the
memory 62 and they may relate to one or more of: a frequency of the reversion of rotations
of the drum 16 during the main drying cycle, a speed of the process or drying air
fan 28, the speed of the drum 16, the heat pump operation parameters.
[0113] Further, the environment temperature Tamb is detected.
[0114] At the beginning of the program S2, the humidity of the laundry is high due to the
fact that the drying program has just started. Therefore, the humidity of the laundry
is above a given threshold. The limit temperature for the compressor is thus set equal
to a second limit temperature, which is valid for "wet" laundry. This second limit
temperature may depend on Tamb. For example, the second limit temperature may be retrieved
in a database in a memory of control unit 60.
[0115] The second limit temperature selection and/or the value of Tamb determine also a
temperature level at which the compressor cooling fan 42 activates or deactivates.
This temperature is for example T1 when the second limit temperature is selected.
The value of the temperature level at which the cooling fan 42 activates or deactivates
as a function of the limit temperature of the compressor is also saved in a memory
of the control unit 60.
[0116] The selected drying cycle, after the above mentioned parameter setting, starts S2.
Preferably, during the drying cycle, the control unit 60 monitors not only the signals
coming from the motor 30 or its inverter, the compressor cooling fan 42, the compressor
motor inverter, the process air fan 28, etc, but also it preferably further monitors
the signals coming from one or more sensors, for example it may receive the signals
from the sensors for the refrigerant temperature Tr, or for the inlet temperature
Ti of the drying air, or for the outlet temperature To of the drying air, or the conductivity
measurements Hum made by the electrodes in the drum 16, or the level of water in the
condensate collector 48 and/or the temporal gradient of a level of water removed from
the outdoor textile to be dried and collected can be measured as well, or relative
to the number of activations of the draining pump 50 of the condensate collector 48.
[0117] The control unit 60 starts the outdoor main drying phase. In certain embodiment of
the invention, previously to the main drying phase, additional phases may be present,
for example an outdoor pre-heating phase. The outdoor main drying phase starts with
the outdoor first sub-phase, step S4. The control unit 60 thus sends command signals
to the drum motor inverter 64 so that a frequency F1 of reversion of rotations of
the drum 16 is reduced with respect to an additional cycle present in the memory 62
of the control unit 60. Preferably, the frequency F1 is lower than the frequency of
any other cycle stored in the memory 62 and selectable by the selector. For example,
the frequency F1 is selected to be equal to 6 reversions per hour.
[0118] Further, one or more of the following can be performed. The number of revolutions
per minute RPM1 of the motor driving the drum 16 in the outdoor first sub-phase may
be increased with respect to the rpm present in the main drying phase of additional
drying cycles present in the laundry machine by means of command signals sent by the
control unit 60 to the drum motor inverter 64, so as to increase the flow rate of
process air in the drum 16. For example, the RPM1 can be of about 2750 rpm or 2900
rpm. Alternatively or in addition, the control unit 60 may send command signals to
the drying air fan motor 70, 30 to increase its velocity with respect to a velocity
in the additional drying cycle selectable in the selector. Alternatively or in addition,
the control unit 60 may send command signal to the compressor motor inverter 66 so
as to increase the velocity of or the power supply to the motor 67 of the compressor
36 with respect to the velocity in the additional main drying cycle.
[0119] The first outdoor sub-phase then takes place with the settings above indicated.
[0120] The control unit 60 further monitors the signals coming from one or more sensors,
for example it may receive the signals from the sensors for the refrigerant temperature
Tr, or for the inlet temperature Ti of the drying air, or for the outlet temperature
To of the drying air, or the conductivity measurements Hum made by the electrodes
in the drum 16, or the level of water in the condensate collector 48. The control
unit 60, therefore, constantly checks the humidity level of the laundry, and compare
it with a threshold. For example, the threshold could for example a humidity below
1 %. If the humidity is below such a threshold S5, the control unit commands the drying
machine 2 to enter the second sub-phase S6 of the outdoor main drying cycle. If the
degree of humidity of the outdoor is not below this first threshold, then the outdoor
first sub-phase continues.
[0121] In the outdoor second sub-phase, step S6, the control unit 60 thus sends command
signals to the drum motor inverter 64 so that the frequency F2 of reversion of rotations
of the drum 16 is reduced with respect to the outdoor first sub-phase. Preferably,
the frequency F2 is lower than the frequency of any other program in the memory 62
selectable by the selector. For example, the frequency F2 is selected to be equal
to zero.
[0122] In this second sub-phase, the compressor limit temperature is also changed, and now
the compressor limit temperature is a first limit temperature which is higher than
the second limit temperature present in the first sub-phase.
[0123] Alternatively or in addition, the control unit 60 may send command signals to the
compressor cooling fan motor 68 in order to increase the temperature T1 at which the
compressor cooling fan 42 activates/deactivates with respect to a temperature at which
the compressor cooling fan activates/deactivates in the additional drying cycle selectable
by the selector. The new temperature is called T2, which is higher than T1.
[0124] Further one or more of the following can be performed. The number of revolutions
per minute RPM2 of the motor driving the drum 16 may be increased with respect to
the outdoor first sub-phase by means of the control unit 60 sending command signals
to drum motor inverter 64. This is particularly advantageous when the drum 16 and
the fan 28 are driven by the same motor 30 because the flow rate of process air in
the drum 16 is increased. For example the RPM can be of about 3000 rpm. Alternatively
or in addition, the control unit 60 may send command signals to the drying air fan
motor 70 to increase its velocity with respect to a velocity in the outdoor first
sub-phase. Alternatively or in addition, the control unit 60 may send command signals
to the compressor motor inverter 66 so as to increase the velocity of or the power
supply to the motor of the compressor 36 with respect to the velocity of or the power
supply to the motor of the compressor in the outdoor first sub-phase.
[0125] The second sub-phase of the outdoor main drying phase terminates when the outdoor
sub-phae has lasted at least for a predetermined duration time tlset S7. This time
interval can be constant, that is, in the memory 62 a fixed value of the tlset is
present, or it may change. For example this duration time may be adjusted depending
on the amount of time at which the outdoor textile inside the drum 16 exceeds a temperature
threshold Tthr which is preferably of about 59°C. Thus, in this embodiment, the outdoor
second sub-phase is terminated when a duration time tlset has elapsed, where tlset
depends on how much time the temperature of the outdoor textile during the second
sub-phase exceeds Tthr. In this way it is ensured that the outdoor textile is kept
at a desired temperature for a minimum time. Therefore this tlset is constantly updated
during the cycle and only the fraction of the time during which the temperature of
the outdoor textile is above Tthr is considered. The second sub-phase therefore terminates
when the tlset is elapsed thereby ensuring that the time during which the temperature
of outdoor textiles is above Tthr is sufficiently long to re-activate (or "re-proof")
the water repellent characteristics of outdoor textiles. Alternatively, it is sensed
how many times the temperature during the second outdoor sub-phase goes below Tthr
and after a given number of times in which the temperatures drop below Tthr, the second
sub-phase is duration time is adjusted, in particular extended. Alternatively, this
tlset can be set depending on the environment temperature and/or pressure conditions
of the environment in which the drying machine 2 is located, for example at the beginning
of the outdoor cycle several parameters of the environment are sensed and a corresponding
fixed value of the tlset is selected, for example from a look-up table or curve of
tlset vs. environment conditions present in the memory 62 of the control unit 60.
[0126] After this tlset has elapsed, then the outdoor second sub-phase is terminated and
then a cooling phase may start, step S8, in order to cool the outdoor textile which
has reached relatively high temperatures due to the re-activation phase (second sub-phase).
[0127] The cooling phase preferably lasts for more than 10 minutes.
[0128] The drying cycle then ends S9.
[0129] Figure 4 shows the temporal behaviour of several parameters during an outdoor cycle
in a drying machine 2 of the invention. In the dryer 2, an outdoor cycle has been
selected. In figure 4, the division between the main drying phase and the cooling
phase has been depicted, as a first vertical line which divides the first and the
second sub-phase of the main drying phase, and the division between the main drying
phase and the cooling phase is shown as well as another vertical line. In the graph,
only the behaviour over time of the curves has been depicted, in order to show the
overall curve shape, the units used are arbitrary.
[0130] The depicted graphs represent the following signal (from top to bottom):
- temperature of the process air at drum INLET (signal from a thermocouple);
- temperature of the process air at drum OUTLET (signal from a thermocouple);
- electric power supply to the dryer (total amount);
- limit temperature of the compressor.
[0131] As clear from the graphs, the temperature in the outdoor first sub-phase constantly
increases and in the outdoor second sub phase is substantially kept constant at a
high value.
[0132] The limit temperature of the compressor is changed from the first to the second sub-phase.
1. A method to operate a laundry drying appliance (2) including:
• a treating chamber (16) where laundry (18) is introduced and treated with process
air;
• a heat pump system (44) having a refrigerant circuit (40) in which a refrigerant
can flow, said refrigerant circuit including a first heat exchanger (32) where the
refrigerant is cooled off, a second heat exchanger (34) where the refrigerant is heated
up, a compressor (36) to pressurize and circulate the refrigerant through the refrigerant
circuit, and a pressure-lowering device (38); said first and/or second heat exchanger
being apt to perform heat exchange between said refrigerant flowing in said refrigerant
circuit and said process air;
• a selector adapted to select alternatively one of a plurality of drying programs,
each drying program including a main drying phase;
said method comprising:
• setting a first limit temperature value representative of the limit temperature
of the compressor (36);
• setting a second limit temperature value representative of the limit temperature
of the compressor (36);
• selecting a drying program among the plurality and starting its drying phase;
• sensing an operating parameter representative of the humidity of the laundry in
the treating chamber (16);
• measuring a temperature value representative of the temperature of said compressor
(36);
• selecting the first limit temperature value for a first plurality of values of the
sensed operating parameter representative of the humidity of the laundry (18) during
the drying phase;
• selecting the second limit temperature value for a second plurality of values of
the sensed operating parameter representative of the humidity of the laundry (18)
during the drying phase; and
• limiting power supply to or switching off said compressor (36) if the measured temperature
value is higher than the first or the second limit temperature value, depending on
which one is selected when the measured temperature value exceeds the limit temperature
value.
2. The method according to claim 1, wherein the step of limiting power supply to or switching
off said compressor (36) if the measured temperature value is higher than the first
or second limit temperature value includes limiting power supply to or switching off
said compressor if any of the following takes place:
• the measured temperature remains above the first or second limit temperature value
for a time interval longer than a time threshold;
• the measured temperature reaches or exceeds the first or second limit temperature
value for a number of times above a number of times threshold;
• the difference between the measured temperature and the first or second limit temperature
value exceeds a temperature difference threshold.
3. The method according to claim 1 or 2, wherein sensing an operating parameter representative
of the humidity of the laundry (18) in the treating chamber (16) includes one or more
of:
• sensing an electrical conductivity of laundry within the treating chamber (16);
• sensing a capacitance of a volume comprising the laundry (18);
• measuring a value representative to a torque of a motor rotating the treating chamber
(16);
• measuring a temperature of the process air leaving the treating chamber (16);
• measuring a temperature difference between a temperature of the process air entering
the treating chamber and a temperature of the process air leaving the treating chamber
(16).
4. The method according to any of the preceding claims, wherein said compressor (36)
includes a casing and an oil circuit in which oil flows, and wherein measuring a temperature
value representative of the temperature of said compressor (36) includes one or more
of:
• measuring a temperature of said compressor casing;
• measuring a temperature of the refrigerant;
• measuring a temperature of the oil.
5. The method according to any of the preceding claims, wherein selecting the first limit
temperature value includes selecting the first limit temperature value when the humidity
of the laundry is below a first humidity threshold.
6. The method according to any of the preceding claims, wherein selecting the second
limit temperature value includes selecting the second limit temperature value when
the humidity of the laundry (18) is above a second humidity threshold.
7. The method according to claim 5 and 6, wherein said first humidity threshold is equal
to the second humidity threshold.
8. The method according to any of claims 5 - 7, including the step of setting the first
or second humidity threshold, the setting of the first or second humidity threshold
being based on one or more of:
• the selected drying program;
• a weight of the laundry (18);
• a laundry fabric type or composition;
• duration of the selected drying program;
• an electrical parameter supplied to a motor rotating the treating chamber (16).
9. The method according to any of the preceding claims, wherein the first or second humidity
threshold is indicative of a humidity value of the laundry of about 1% or less.
10. The method according to any of the preceding claims, including:
• sensing a temperature of an environment external to said laundry drying appliance
(2); and
• wherein first or second limit temperature value is a function of said environment
temperature.
11. The method according to any of the preceding claims, wherein said laundry drying appliance
(2) includes a fan (42) adapted to blow air towards said compressor (36) to cool the
same and wherein selecting the first limit temperature value for a first plurality
of values of the sensed operating parameter representative of the humidity of the
laundry during the drying phase; or selecting the second limit temperature value for
a second plurality of values of the sensed operating parameter representative of the
humidity of the laundry during the drying phase, includes selecting a first or second
temperature threshold, respectively, provided to
• activate and /or deactivate said fan (42);
• modify the airflow supplied by said fan (42).
12. The method according to any of the preceding claims, wherein said plurality of drying
programs includes an outdoor drying program for drying outdoor textiles which have
a waterproof and breathable thin film material with a micro-porous structure, and
at least an additional drying program for drying other types of textiles, wherein
the outdoor drying program includes an outdoor drying phase having settings for a
frequency of reversion of rotations of the drum and for the heat pump operation and
the additional drying program comprises an additional drying phase having settings
for a frequency of reversion of rotations of the drum and for the heat pump operation;
and wherein:
• selecting a drying program among the plurality and starting its drying phase includes
selecting the outdoor drying program; and
• reversing the rotation of the treating chamber in the outdoor drying program at
a frequency lower than a frequency in the additional main drying phase at least for
a portion of the drying phase.
13. The method according to claim 12, wherein said outdoor drying program includes a first
drying sub-phase and a second-drying sub-phase, including:
• in the second drying sub-phase, reversing the rotation of the drum at a frequency
(F2) lower than the drum rotation reversal frequency (F1) operated in the outdoor
first sub-phase; and
• in the second drying sub-phase, selecting the first limit temperature of the compressor
(36).
14. The method according to claim 12 or 13, wherein said outdoor drying program includes
a first drying sub-phase and a second-drying sub-phase, and including:
• in the outdoor second drying sub-phase, increasing a flow rate of the process air
in the treating chamber with respect to a flow rate in the outdoor first drying sub-phase
and with respect to a flow rate in the additional drying phase.
15. The method according to any of the preceding claims, wherein the laundry drying appliance
(2) includes an overload protector adapted to cut power to said compressor, said overload
protector defining a tripping temperature, and wherein setting a first limit temperature
value or setting a second limit temperature value representative of the limit temperature
of the compressor includes setting a first or second limit temperature value lower
than the tripping temperature of the overload protector.
16. A laundry drying appliance (2) having a control unit (60) programmed for implementing
the method according to any claim 1 to 15.
1. Verfahren zum Betreiben einer Wäschetrocknervorrichtung (2), Folgendes umfassend:
• eine Behandlungskammer (16), in die Wäsche (18) eingeleitet wird und in der diese
mit Prozessluft behandelt wird;
• ein Wärmepumpensystem (44), das einen Kühlmittelkreislauf (40) aufweist, in dem
ein Kühlmittel strömen kann, wobei der Kühlmittelkreislauf einen ersten Wärmetauscher
(32), in dem das Kühlmittel abgekühlt wird, einen zweiten Wärmetauscher (34), in dem
das Kühlmittel erwärmt wird, einen Verdichter (36), um das Kühlmittel unter Druck
zu setzen und durch den Kühlmittelkreislauf zu zirkulieren, und eine Druckreduzierungsvorrichtung
(38) umfasst; wobei der erste und/oder zweite Wärmetauscher dazu geeignet ist, einen
Wärmeaustausch zwischen dem im Kühlmittelkreislauf strömenden Kühlmittel und der Prozessluft
durchzuführen;
• einen Wahlschalter, der dazu eingerichtet ist, alternativ eines von mehreren Trockenprogrammen
auszuwählen, wobei jedes Trockenprogramm eine Haupttrocknungsphase umfasst;
wobei das Verfahren Folgendes umfasst:
• Einstellen eines ersten Temperaturgrenzwerts, der die Grenztemperatur des Verdichters
(36) darstellt;
• Einstellen eines zweiten Temperaturgrenzwerts, der die Grenztemperatur des Verdichters
(36) darstellt;
• Auswählen eines Trockenprogramms aus den mehreren Programmen und Beginnen dessen
Trockenphase;
• Erfassen eines Betriebsparameters, der die Feuchtigkeit der Wäsche in der Behandlungskammer
(16) darstellt;
• Messen eines Temperaturwerts, der die Temperatur des Verdichters (36) darstellt;
• Auswählen des ersten Temperaturgrenzwerts für erste mehrere Werte des erfassten
Betriebsparameters, der die Feuchtigkeit der Wäsche (18) während der Trockenphase
darstellt;
• Auswählen des zweiten Temperaturgrenzwerts für zweite mehrere Werte des erfassten
Betriebsparameters, der die Feuchtigkeit der Wäsche (18) während der Trockenphase
darstellt; und
• Einschränken der Stromversorgung oder Ausschalten des Verdichters (36), wenn der
gemessene Temperaturwert über dem ersten oder zweiten Temperaturgrenzwert liegt, je
nachdem, welche Aktion ausgewählt ist, wenn der gemessene Temperaturwert den Temperaturgrenzwert
übersteigt.
2. Verfahren nach Anspruch 1, wobei der Schritt des Einschränkens der Stromversorgung
oder Ausschaltens des Verdichters (36), wenn der gemessene Temperaturwert über dem
ersten oder zweiten Temperaturgrenzwert liegt, das Einschränken der Stromversorgung
oder Ausschalten des Verdichters umfasst, wenn eines der folgenden Ereignisse eintritt:
• die gemessene Temperatur bleibt für einen Zeitraum, der länger als ein Zeitschwellenwert
ist, über dem ersten oder zweiten Temperaturgrenzwert;
• die gemessene Temperatur erreicht oder übersteigt den ersten oder zweiten Temperaturgrenzwert
mehrere Male über einem dafür vorgesehenen Schwellenwert;
• die Differenz zwischen der gemessenen Temperatur und dem ersten oder zweiten Temperaturgrenzwert
übersteigt einen Temperaturdifferenzschwellenwert.
3. Verfahren nach Anspruch 1 oder 2, wobei das Erfassen eines Betriebsparameters, der
die Feuchtigkeit der Wäsche (18) in der Behandlungskammer (16) darstellt, eine oder
mehrere der folgenden Aktionen umfasst:
• Erfassen einer elektrischen Leitfähigkeit der Wäsche innerhalb der Behandlungskammer
(16);
• Erfassen einer Kapazität eines die Wäsche (18) umfassenden Raums;
• Messen eines Werts, der ein Drehmoment eines Motors, der die Behandlungskammer (16)
dreht, darstellt;
• Messen einer Temperatur der Prozessluft, die die Behandlungskammer (16) verlässt;
• Messen einer Temperaturdifferenz zwischen einer Temperatur der Prozessluft, die
in die Behandlungskammer eintritt, und einer Temperatur der Prozessluft, die die Behandlungskammer
(16) verlässt.
4. Verfahren nach einem der vorstehenden Ansprüche, wobei der Verdichter (36) ein Gehäuse
und einen Ölkreislauf, in dem Öl fließt, umfasst und wobei das Messen eines Temperaturwerts,
der die Temperatur des Verdichters (36) darstellt, eine oder mehrere der folgenden
Aktionen umfasst:
• Messen der Temperatur des Verdichtergehäuses;
• Messen der Temperatur des Kühlmittels;
• Messen der Temperatur des Öls.
5. Verfahren nach einem der vorstehenden Ansprüche, wobei das Auswählen des ersten Temperaturgrenzwerts
das Auswählen des ersten Temperaturgrenzwerts, wenn die Feuchtigkeit der Wäsche unter
einem ersten Feuchtigkeitsschwellenwert liegt, umfasst.
6. Verfahren nach einem der vorstehenden Ansprüche, wobei das Auswählen des zweiten Temperaturgrenzwerts
das Auswählen des zweiten Temperaturgrenzwerts, wenn die Feuchtigkeit der Wäsche (18)
über einem zweiten Feuchtigkeitsschwellenwert liegt, umfasst.
7. Verfahren nach Anspruch 5 und 6, wobei der erste Feuchtigkeitsschwellenwert und der
zweite Feuchtigkeitsschwellenwert gleich sind.
8. Verfahren nach einem der Ansprüche 5-7, den Schritt des Einstellens des ersten oder
zweiten Feuchtigkeitsschwellenwerts umfassend, wobei das Einstellen des ersten oder
zweiten Feuchtigkeitsschwellenwerts auf einem oder mehreren der folgenden Elemente
basiert:
• dem ausgewählten Trockenprogramm;
• dem Gewicht der Wäsche (18);
• der Stoffart oder -zusammensetzung der Wäsche;
• der Dauer des ausgewählten Trockenprogramms;
• einem elektrischen Parameter, der einem Motor, der die Behandlungskammer (16) dreht,
zugeführt wird.
9. Verfahren nach einem der vorstehenden Ansprüche, wobei der erste oder zweite Feuchtigkeitsschwellenwert
einen Feuchtigkeitswert der Wäsche von etwa 1 % oder weniger angibt.
10. Verfahren nach einem der vorstehenden Ansprüche, Folgendes umfassend:
• Erfassen einer Temperatur einer Außenumgebung der Wäschetrocknervorrichtung (2);
und
• wobei der erste oder zweite Temperaturgrenzwert eine Funktion der Umgebungstemperatur
ist.
11. Verfahren nach einem der vorstehenden Ansprüche, wobei die Wäschetrocknervorrichtung
(2) ein Gebläse (42) umfasst, das dazu eingerichtet ist, Luft zum Verdichter (36)
zu blasen, um diesen abzukühlen, und wobei das Auswählen des ersten Temperaturgrenzwerts
für erste mehrere Werte des erfassten Betriebsparameters, der die Feuchtigkeit der
Wäsche während der Trockenphase darstellt; oder das Auswählen des zweiten Temperaturgrenzwerts
für zweite mehrere Werte des erfassten Betriebsparameters, der die Feuchtigkeit der
Wäsche während der Trockenphase darstellt, das Auswählen eines ersten bzw. zweiten
Temperaturschwellenwerts umfasst, der vorgesehen ist, um
• das Gebläse (42) zu aktivieren und/oder deaktivieren;
• den vom Gebläse (42) zugeführten Luftstrom zu modifizieren.
12. Verfahren nach einem der vorstehenden Ansprüche, wobei die mehreren Trockenprogramme
ein Outdoor-Trockenprogramm zum Trocknen von Outdoor-Textilien, die wasserdichtes
und atmungsaktives, dünnes Folienmaterial mit einer mikroporösen Struktur aufweisen,
und mindestens ein zusätzliches Trockenprogramm zum Trocknen anderer Textilarten umfasst,
wobei das Outdoor-Trockenprogramm eine Outdoor-Trockenphase umfasst, die Einstellungen
für eine Trommeldrehungs- und Wärmepumpenbetriebsumkehrhäufigkeit aufweist und wobei
das zusätzliche Trockenprogramm eine zusätzliche Trockenphase umfasst, die Einstellungen
für eine Trommeldrehungs- und Wärmepumpenbetriebsumkehrhäufigkeit aufweist; und wobei:
• das Auswählen eine Trockenprogramms von den mehreren Programmen und das Beginnen
dessen Trockenphase das Auswählen des Outdoor-Trockenprogramms umfasst; und
• das Umkehren der Drehung der Behandlungskammer im Outdoor-Trockenprogramm zumindest
für einen Abschnitt der Trockenphase mit einer geringeren Häufigkeit als bei der zusätzlichen
Haupttrockenphase erfolgt.
13. Verfahren nach Anspruch 12, wobei das Outdoor-Trockenprogramm eine erste Teiltrockenphase
und eine zweite Teiltrockenphase umfasst, Folgendes umfassend:
• in der zweiten Teiltrockenphase das Umkehren der Trommeldrehung mit einer Häufigkeit
(F2), die geringer als die Trommeldrehungsumkehrhäufigkeit (F1) in der ersten Outdoor-Teilphase
ist; und
• in der zweiten Teiltrockenphase das Auswählen der ersten Grenztemperatur des Verdichters
(36).
14. Verfahren nach Anspruch 12 oder 13, wobei das Outdoor-Trockenprogramm eine erste Teiltrockenphase
und eine zweite Teiltrockenphase umfasst und Folgendes umfassend:
• in der zweiten Outdoor-Teiltrockenphase Erhöhen einer Strömungsgeschwindigkeit der
Prozessluft in der Behandlungskammer in Bezug zu einer Strömungsgeschwindigkeit in
der ersten Outdoor-Teiltrockenphase und in Bezug zu einer Strömungsgeschwindigkeit
in der zusätzlichen Trockenphase.
15. Verfahren nach einem der vorstehenden Ansprüche, wobei die Wäschetrocknervorrichtung
(2) einen Überlastungsschutz umfasst, der dazu eingerichtet ist, die Stromversorgung
zum Verdichter zu unterbrechen, wobei der Überlastungsschutz eine Auslösetemperatur
definiert und wobei das Einstellen eines ersten Temperaturgrenzwerts oder das Einstellen
eines zweiten Temperaturgrenzwerts, der die Grenztemperatur des Verdichters darstellt,
das Einstellen eines ersten oder zweiten Temperaturgrenzwerts umfasst, der unter der
Auslösetemperatur des Überlastungsschutzes liegt.
16. Wäschetrocknervorrichtung (2), die eine Steuereinheit (60) aufweist, die dazu programmiert
ist, das Verfahren nach einem der Ansprüche 1 bis 15 auszuführen.
1. Procédé d'utilisation d'un appareil (2) de séchage de linge comprenant :
• une chambre (16) de traitement où du linge (18) est introduit et traité avec de
l'air de processus ;
• un système (44) de pompe à chaleur doté d'un circuit (40) d'agent frigorigène dans
lequel un agent frigorigène peut s'écouler, ledit circuit d'agent frigorigène comprenant
un premier échangeur (32) de chaleur où l'agent frigorigène est refroidi, un second
échangeur (34) de chaleur où l'agent frigorigène est chauffé, un compresseur (36)
servant à mettre sous pression et à faire circuler l'agent frigorigène à travers le
circuit d'agent frigorigène, et un dispositif abaisseur (38) de pression ; ledit premier
et/ou ledit second échangeur de chaleur étant aptes à réaliser un échange de chaleur
entre ledit agent frigorigène s'écoulant dans ledit circuit d'agent frigorigène et
ledit air de processus ;
• un sélecteur conçu pour sélectionner au choix un programme parmi une pluralité de
programmes de séchage, chaque programme de séchage comprenant une phase principale
de séchage ;
ledit procédé comportant les étapes consistant à :
• régler une première valeur de température limite représentative de la température
limite du compresseur (36) ;
• régler une seconde valeur de température limite représentative de la température
limite du compresseur (36) ;
• sélectionner un programme de séchage parmi la pluralité et démarrer sa phase de
séchage ;
• détecter un paramètre de fonctionnement représentatif de l'humidité du linge dans
la chambre (16) de traitement ;
• mesurer une valeur de température représentative de la température dudit compresseur
(36) ;
• sélectionner la première valeur de température limite pour une première pluralité
de valeurs du paramètre de fonctionnement détecté représentatif de l'humidité du linge
(18) pendant la phase de séchage ;
• sélectionner la seconde valeur de température limite pour une seconde pluralité
de valeurs du paramètre de fonctionnement détecté représentatif de l'humidité du linge
(18) pendant la phase de séchage ; et
• limiter l'alimentation électrique dudit compresseur (36) ou l'éteindre si la valeur
de température mesurée est supérieure à la première ou à la seconde valeur de température
limite, suivant celle qui est sélectionnée lorsque la valeur de température mesurée
dépasse la valeur de température limite.
2. Procédé selon la revendication 1, l'étape consistant à limiter l'alimentation électrique
dudit compresseur (36) ou à l'éteindre si la valeur de température mesurée est supérieure
à la première ou à la seconde valeur de température limite comprenant le fait de limiter
l'alimentation électrique dudit compresseur ou l'éteindre si l'un quelconque des événements
suivants se produit :
• la température mesurée reste supérieure à la première ou à la seconde valeur de
température limite pendant un intervalle de temps plus long qu'un seuil de temps ;
• la température mesurée atteint ou dépasse la première ou la seconde valeur de température
limite un nombre de fois supérieur à un seuil de nombre de fois ;
• la différence entre la température mesurée et la première ou la seconde valeur de
température limite dépasse un seuil de différence de température.
3. Procédé selon la revendication 1 ou 2, la détection d'un paramètre de fonctionnement
représentatif de l'humidité du linge (18) dans la chambre (16) de traitement comprenant
une ou plusieurs des actions consistant à :
• détecter une conductivité électrique de linge à l'intérieur de la chambre (16) de
traitement ;
• détecter une capacitance d'un volume comportant le linge (18) ;
• mesurer une valeur représentative d'un couple d'un moteur faisant tourner la chambre
(16) de traitement ;
• mesurer une température de l'air de processus quittant la chambre (16) de traitement
;
• mesurer une différence de température entre une température de l'air de processus
entrant dans la chambre de traitement et une température de l'air de processus quittant
la chambre (16) de traitement.
4. Procédé selon l'une quelconque des revendications précédentes, ledit compresseur (36)
comprenant un carter et un circuit d'huile dans lequel circule de l'huile, et la mesure
d'une valeur de température représentative de la température dudit compresseur (36)
comprenant une ou plusieurs des actions consistant à :
• mesurer une température dudit carter de compresseur ;
• mesurer une température de l'agent frigorigène ;
• mesurer une température de l'huile.
5. Procédé selon l'une quelconque des revendications précédentes, la sélection de la
première valeur de température limite comprenant la sélection de la première valeur
de température limite lorsque l'humidité du linge est inférieure à un premier seuil
d'humidité.
6. Procédé selon l'une quelconque des revendications précédentes, la sélection de la
seconde valeur de température limite comprenant la sélection de la seconde valeur
de température limite lorsque l'humidité du linge (18) est supérieure à un second
seuil d'humidité.
7. Procédé selon les revendications 5 et 6, ledit premier seuil d'humidité étant égal
au second seuil d'humidité.
8. Procédé selon l'une quelconque des revendications 5 à 7, comprenant l'étape consistant
à régler le premier ou le second seuil d'humidité, le réglage du premier ou du second
seuil d'humidité étant basé sur un ou plusieurs éléments parmi :
• le programme de séchage sélectionné ;
• un poids du linge (18) ;
• un type de tissu ou une composition du linge ;
• la durée du programme de séchage sélectionné ;
• un paramètre électrique fourni à un moteur faisant tourner la chambre (16) de traitement.
9. Procédé selon l'une quelconque des revendications précédentes, le premier ou le second
seuil d'humidité étant indicatif d'une valeur d'humidité du linge d'environ 1% ou
moins.
10. Procédé selon l'une quelconque des revendications précédentes, comprenant :
• la détection d'une température d'un environnement extérieur audit appareil (2) de
séchage de linge ; et
• la première ou la seconde valeur de température limite étant fonction de ladite
température de l'environnement.
11. Procédé selon l'une quelconque des revendications précédentes, ledit appareil (2)
de séchage de linge comprenant un ventilateur (42) conçu pour souffler de l'air vers
ledit compresseur (36) afin de le refroidir et la sélection de la première valeur
de température limite pour une première pluralité de valeurs du paramètre de fonctionnement
détecté représentatif de l'humidité du linge pendant la phase de séchage ; ou la sélection
de la seconde valeur de température limite pour une seconde pluralité de valeurs du
paramètre de fonctionnement détecté représentatif de l'humidité du linge pendant la
phase de séchage, comprenant la sélection d'un premier ou d'un second seuil de température,
respectivement, mis en place pour
• activer et/ou désactiver ledit ventilateur (42) ;
• modifier l'écoulement d'air fourni par ledit ventilateur (42).
12. Procédé selon l'une quelconque des revendications précédentes, ladite pluralité de
programmes de séchage comprenant un programme de séchage d'extérieur servant à sécher
des textiles d'extérieur dotés d'un matériau en film mince imperméable à l'eau et
aéré présentant une structure microporeuse, et au moins un programme de séchage supplémentaire
servant à sécher d'autres types de textiles, le programme de séchage d'extérieur comprenant
une phase de séchage d'extérieur dotée de réglages pour une fréquence d'inversions
de rotation du tambour et pour le fonctionnement de la pompe à chaleur et le programme
de séchage supplémentaire comportant une phase de séchage supplémentaire dotée de
réglages pour une fréquence d'inversions de rotation du tambour et pour le fonctionnement
de la pompe à chaleur ; et :
• la sélection d'un programme de séchage parmi la pluralité et le démarrage de sa
phase de séchage comprenant la sélection du programme de séchage d'extérieur ; et
• l'inversion de la rotation de la chambre de traitement dans le programme de séchage
d'extérieur à une fréquence inférieure à une fréquence dans la phase principale de
séchage supplémentaire au moins pendant une partie de la phase de séchage.
13. Procédé selon la revendication 12, ledit programme de séchage d'extérieur comprenant
une première sous-phase de séchage et une seconde sous-phase de séchage, comprenant
les étapes consistant :
• dans la seconde sous-phase de séchage, à inverser la rotation du tambour à une fréquence
(F2) inférieure à la fréquence (F1) d'inversion de rotation du tambour actionné dans
la première sous-phase d'extérieur ; et
• dans la seconde sous-phase de séchage, à sélectionner la première température limite
du compresseur (36).
14. Procédé selon la revendication 12 ou 13, ledit programme de séchage d'extérieur comprenant
une première sous-phase de séchage et une seconde sous-phase de séchage, et comprenant
l'étape consistant :
• dans la seconde sous-phase de séchage d'extérieur, à augmenter un débit de l'air
de processus dans la chambre de traitement par rapport à un débit dans la première
sous-phase de séchage d'extérieur et par rapport à un débit dans la phase de séchage
supplémentaire.
15. Procédé selon l'une quelconque des revendications précédentes, l'appareil (2) de séchage
de linge comprenant un moyen de protection contre les surcharges conçu pour couper
l'alimentation dudit compresseur, ledit moyen de protection contre les surcharges
définissant une température de déclenchement, et le réglage d'une première valeur
de température limite ou le réglage d'une seconde valeur de température limite représentative
de la température limite du compresseur comprenant le réglage d'une première ou d'une
seconde valeur de température limite inférieure à la température de déclenchement
du moyen de protection contre les surcharges.
16. Appareil (2) de séchage de linge doté d'une unité (60) de commande programmé pour
mettre en œuvre le procédé selon l'une quelconque des revendications 1 à 15.