Technical field
[0001] The present invention relates to a laundry dryer having an improved process air conduit.
Background of the invention
[0002] The heat pump technology in a laundry dryer is at present the most efficient way
to dry clothes in terms of energy consumption. In a heat pump system of the laundry
dryer an air stream flows in a closed air stream circuit, called process air circuit.
Further, the heat pump system includes a closed refrigerant circuit. The air stream
is moved by a (main) fan, passes through a laundry chamber, which is preferably formed
as a rotatable laundry drum, and removes there water from wet clothes. Then, the air
stream is cooled down and dehumidified in an evaporator, heated up in a condenser
and re-inserted into the laundry drum again. The refrigerant is compressed by a compressor,
condensed in the condenser, expanded in an expansion device and then vaporized in
the evaporator.
[0003] Thus, the condenser and the evaporator are components of the air stream circuit as
well as of the refrigerant circuit. The condenser and the evaporator are heat exchangers
between the air stream circuit and the refrigerant circuit.
[0004] Usually, the components of the heat pump system (as described above) are placed in
a basement of the laundry dryer. The basement of a laundry dryer is part of a casing,
which includes in addition to the basement also walls, substantially vertically supported
from the basement, such as a front wall and a rear wall, and lateral walls. In the
casing, a drum (where the laundry is introduced in order to dry the same) is rotatably
supported. In particular, the compressor, the evaporator and the condenser are arranged
in said basement below the laundry drum. A process air duct of the air stream circuit
has to pass the basement of the dryer, bringing the humid air to the evaporator and
reintroducing the dry air from the condenser into the drum. The process air duct in
the basement can be formed by joining together two shells, an upper shell portion
and a lower shell portion, which together form the basement.
[0005] The shape of the process air duct within the basement plays an important role when
it comes to the efficiency of the laundry dryer and the noise produced by the same.
[0006] Indeed, any sharp bend or corners which are present in the air stream circuit cause
pressure drops and turbulences increasing the energy consumption and the noise. Indeed,
a duct having for example sudden change in cross section is far away from the best
aerodynamic shape, this latter being the shape reducing considerably air resistance
during the flow.
[0007] However, it is rather complex to modify the outline and shape of the process air
duct where process air flows within the basement. The various component of the heat
pump, with particular reference to the heat exchangers and the compressor, as well
as the motor of the dryer, are rather "bulky", and repositioning of the same are limited
due to the confined volume present in the basement of the dryer.
[0008] The above applies also to laundry dryer without a heat pump system, but having an
air-air type heat exchanger, wherein drying air is dehumidified by a cooling airflow
passing through said heat exchanger.
[0009] It is known that prior art dryer includes a basement where a process air duct is
formed. The process air within the basement process air duct is moved by the fan of
the process air circuit. The process air exits the basement process air duct in order
to be fed to the fan which blows the air to the drum. Between the outlet present in
the basement and the air inlet of the fan, a flange is present, which restricts the
dimension of the process air channel. Such flange or restriction causes turbulences
and vortices in the process air flow, lowering the dryer efficiency as well as causing
noise.
[0010] It is an object of the present invention to provide a laundry dryer with a process
air generator, wherein the flow of the process air is improved, with particular reference
to the air stream flow between the basement of the laundry dryer and the air inlet
of the fan.
[0011] Applicant has realized via numerous experiments that the efficiency of the dryer
and of the process air generator, e.g. a heat pump, system can be improved avoiding
such a flange and therefore changing the outline of the basement process air duct
and of the air inlet to the fan.
[0012] The absence of such a flange prevents the formation of "sharp corners" inside the
basement process air duct, so that the pressure drops in the basement process air
duct are reduced. The process air flow from the condenser to the basement outlet is
optimized. The heat exchange between the refrigerant circuit and the air stream circuit
is increased. The dimensions of the evaporator and condenser may be reduced.
[0013] In addition, the energy consumption of the motors for the compressor and the fan
is reduced. Further, the noise of the laundry dryer is reduced.
[0014] According to a first aspect, the invention relates to a laundry dryer including:
- a dryer casing having a front wall, a rear wall, lateral walls, and a basement defining
a basement plane;
- a drum rotatably accommodated within said casing and accessible via a door connected
to said front door;
- a process air conduit wherein drying process air is apt to flow, said process air
conduit being connected to said drum so that said process air flows therethrough;
- a process air generator, apt to generate drying process air, said process air generator
being located within said process air conduit;
- said process air conduit including a basement process air duct formed in said basement,
said basement process air duct having walls and including a basement process air outlet
where process air exits said basement,
- a motor having a shaft defining a motor axis, said motor axis passing through an aperture
provided in the basement air duct and substantially at or in proximity of a center
of said basement process air outlet;
- wherein a plane perpendicular to said basement plane and sectioning said basement
along said motor axis divides said basement process air duct in an outer and in an
inner portion, said outer portion being the portion not passing through a longitudinal
centreline of the casing;
- wherein a section by a plane passing through said motor axis and sectioning said basement
process duct portion and said basement outlet in said outer portion defines a curve,
a starting point of said curve being located at said basement process air outlet and
an end point of said curve being located at said aperture; and
- wherein in said section by said plane passing through the motor axis, the distance
between a point of said curve and said motor axis is a decreasing monotone function
if the position of said point moves from said starting point to said end point.
[0015] In the following, with the term "dryer" both drying machines which dry only as well
as combined washer-dryers capable of performing washing and drying cycles are meant.
[0016] The dryer of the invention includes a drying chamber, such as a drum, in which the
load, e.g. clothes or laundry, to be dried is placed.
[0017] The drum is part of an air process circuit, in particular a closed-loop circuit in
case of a condensed dryer or an open circuit in case of a vented dryer, which in both
cases includes an air conduit for channelling a stream of air to dry the load. The
process air circuit is connected with its two opposite ends to the drum. More specifically,
hot dry air is fed into the drying chamber, flowing over the laundry, and the resulting
humid (and to a lower temperature cooled down) air exits the same. In case of a closed-loop
drying air circuit, the humid air stream, rich in water vapor, is then fed into a
humidity removal element, such as a heat exchanger. In a preferred embodiment of the
invention, the humid air is fed to an evaporator of a heat pump system, where the
moist process air is further cooled down and the humidity present therein condenses.
The resulting cool dry air is then heated up before re-entering again in the drying
chamber by means of a hot drying air generator, which can be for example a condenser
of the heat pump system, and the whole loop is repeated till the end of the drying
cycle. Alternatively or in addition, to remove humidity from humid air stream exiting
the drum, an air-air type heat exchanger may be used. Such heat exchanger receives
ambient air as cooling fluid to cool down and remove humidity from humid air stream
passing therethrough. Furthermore, the hot drying air generator may comprise an electrical
or gas powered heating device. In a vented dryer, ambient air is taken into the dryer
via an inlet duct, such air is heated up by a hot drying air generator, such as condenser
of the heat pump system and/or an electrical or gas powered heating device, before
entering the drum. Heated air flowing through and on humid laundry contained in the
drum, removes humidity from laundry. Humid air stream exiting the drum may be optionally
dehumidified by an evaporator of a heat pump system, or an air-air type heat exchanger
as explained above, before being exhausted outside the dryer.
[0018] The dryer furthermore includes a casing or bearing structure, comprising a basement,
and preferably also a front wall, a rear wall and lateral walls. The front wall is
advantageously provided with a through opening, at which a door is mounted to access
the drum in order to store the laundry for drying purposes, or to remove the dry laundry
at the end of the drying process. Preferably, a rim of the rear end of the drum abuts
against the rear wall of the casing, and even more preferably a gasket is interposed
therebetween; as well as a rim of the front end of the drum abuts against the front
wall with also preferably a gasket therebetween.
[0019] Within the casing, the drum is rotatably mounted for rotating according to a horizontal
or substantially horizontal or tilted rotational axis. Support element(s) for rotatably
supporting the drum is/are provided for within the casing. The drum is rotated preferably
by means of a motor which defines a motor axis, for example which corresponds to the
axis of a motor shaft.
[0020] In an advantageous embodiment, said drum support element includes a drum shaft, said
shaft passing through said rear or back wall of the drum, said shaft defining said
axis of rotation of said drum. Alternatively or in addition, said drum support element
includes a roller, the axis of the roller being substantially parallel to the axis
of rotation of said drum.
[0021] The basement of the dryer of the invention includes a portion of the process air
conduit. This portion of the process air conduit realized in the basement is called
a basement process air duct. Within the basement process air duct or outside the same
but still within the basement, the process air generator, e.g. both heat exchangers
of the heat pump system are preferably located. Furthermore, the basement process
air duct channels the process air exiting the process air generator such as the heat
pump to an outlet of the basement. From the outlet of the basement, the process air
- dried by the process air generator - is fed, for example via an additional portion
of the process air conduit realized preferably in the rear wall of the casing, to
the drum so as to dry the laundry therein.
[0022] The motor axis exits the basement also through the outlet of the basement. The motor
axis can be for example used additionally to drive a main fan of the process air conduit,
apt to blow air from the basement back to the drum. The axis of the motor substantially
passes through a center of the basement outlet, or in proximity of such a center.
In order to exit the basement, the motor shaft has to pass through the process air
duct in the basement, as better detailed below.
[0023] The basement process air duct may include one or more lateral walls depending on
its geometry. If the geometry of the duct is substantially cylindrical or of a cylindroid,
the basement process air duct includes a single lateral wall having circular or round
or substantially circular or substantially roundish cross section, which may change
in diameter depending on the position in which the cross section is taken. Alternatively,
the basement process air duct may include parallel flat lateral wall, for example
substantially perpendicular to the basement.
[0024] In a standard operative position, the basement of the dryer is positioned on a floor
or other substrate on which the dryer performs its standard operations (e.g. drying
and/or washing and/or spinning cycles). Such positioning defines a horizontal or at
least substantially horizontal plane, which is called the basement plane (X, Y). Plane
parallel to the basement plane are therefore substantially horizontal planes.
[0025] In this standard operative position, also other terms are well defined: "front" or
"rear" or "back", "top" or "bottom", "upper" or "lower" are always referred to the
normal standard configuration of a dryer with the basement positioned on a floor.
The front wall of the dryer is defined by the wall in which the door from which the
drum is accessed is positioned. Given the horizontal plane on which the laundry is
located, "top" and "bottom" - as their normal common meaning - refer to the position
of an object along a vertical axis.
[0026] Preferably, on the basement of the dryer the rear, the front, and the lateral walls
of the casing of the dryer are mounted. Even more preferably, the casing includes
further walls, for instance a top wall.
[0027] In a top view of the dryer, the basement can be considered as "divided" in two longitudinal
halves by the axis of rotation of the drum (or the projection of said axis onto the
basement plane). Whether the axis is horizontal (thus parallel to the basement plane
(X,Y)) or tilted with respect to the latter, on a top view of the basement, the projection
of the drum axis divides the basement in two halves, a first or left longitudinal
half and a second or right longitudinal half. In other words, taking a plane which
is perpendicular to the basement plane and which passes through the rotational axis
of the drum, which generally coincides with the centerline of the basement, this plane
virtually sections the basement in two longitudinal halves. This plane, called first
plane, when sectioned by a plane parallel to the (X, Y) plane, defines a line of division
of the basement in two in a top view.
[0028] The two halves do not need to be identical. In other words with a first and a second
half, a "right" and a "left" portion of the basement with respect of the above mentioned
plane (first plane) passing through the rotational axis of the drum and perpendicular
to the basement plane are meant. The projection on the basement of such rotational
axis can be thus shifted from the centerline of the basement. Preferably, the centerline
and the projection of the rotational axis of the drum coincide.
[0029] The layout of the basement of the dryer of the invention is the following.
[0030] The process air generator, e.g. the heat exchangers of the heat pump, are located
within the basement air conduit and extend for the majority of their volume within
the first longitudinal half of the basement, e.g. they are substantially located for
the majority of their volume to the left of the rotational axis of the drum. The heat
exchangers can be completely contained within the first longitudinal half of the basement
or part of their volume, the minority, can also extend within the second longitudinal
half of the basement. Also, an exit of process air from the condenser, i.e. the surface
of the condenser from which process air exits, is located within the first longitudinal
half of the basement, at least for most of its area.
[0031] On the other end, the outlet of process air from the basement is located within the
second longitudinal half of the basement, i.e. on the half of the basement right to
the rotational axis of the drum. Preferably, the basement outlet is realized in the
rear part of the basement, i.e. facing the real wall of the cabinet. Thus, in order
to channel the process air outside the basement, the basement duct extends from the
exit of the condenser to the outlet of the basement starting from the first longitudinal
half of the basement and reaching the second longitudinal half of the basement.
[0032] Preferably, the motor is located within the second longitudinal half of the basement.
Due to the fact that the basement duct extends from the exit of the condenser to the
outlet of the basement, in order for the motor to have a motor shaft exiting the basement
through the outlet as well, the shaft has to form a hole or aperture in the wall(s)
of the basement process air duct. This motor shaft preferably rotates also the fan,
in particular the impeller of the same.
[0033] According to the invention, the basement process air duct is forming a "smooth" channel
to channel process air from the basement to the impeller of the fan, as better detailed
below. The presence of a smooth channel is particularly relevant in proximity of the
outlet of the basement, where abrupt changes in the configuration of the basement
process air duct would cause turbulences, vortexes and a sharp reduction in the efficiency
of the dryer, as well as of the heat pump system.
[0034] A "smooth" channel means, in this contest that close to the basement process air
outlet there are no "relevant" obstacles for the process air flow, such as flanges
that abruptly reduce the diameter of the process air duct in the direction of the
process air flow from the process air generator towards the basement process air outlet.
[0035] In order to have a smooth flow of air from the basement to the outlet, the basement
duct which terminates with the basement process air outlet has a specific shape according
to the invention.
[0036] Considering now a plane which is perpendicular to the basement plane and which includes
the motor axis, this plane divides the basement duct in two parts, which will be called
in the following inner and outer portions. The outer portion is the part which is
not including the centreline of the casing, while the inner part is the part that
passes through the centerline of the casing.
[0037] This plane, in case the basement process air outlet is a circle, sections the outlet
is two semi-circles and the basement duct in the inner portion, which extends from
the second longitudinal half of the basement into the first longitudinal half, and
in the outer portion which is confined within the second longitudinal half of the
basement and is sandwiched between a lateral wall of the casing and the sectioning
plane above described passing through the motor axis.
[0038] In the following, only the part of the basement duct within the outer portion is
considered, and in particular its shape.
[0039] A further plane is considered, which passes through the motor axis. This plane does
not have to have any specific angle with the basement plane, as long as it sections
the outer portion of the basement duct. Substantially any plane passing through the
motor axis is considered due to the fact that the outer portion spans an angle 180°
around the motor axis. Each of these further planes sections the outer portion of
the basement duct, defining a curve. In other words, a section along this plane passing
through the motor axis sections the basement duct at the outer portion in such a way
that the walls of the basement duct defines a curve in the section itself. This curve
has the following shape.
[0040] One point of the curve belongs to the outlet of the basement. This is always true
because the motor axis passes through the outlet and thus all planes passing through
the motor axis also sections the outlet of the basement. This point at the outlet
is one of the ends of the curve and it is called the starting point of the curve.
[0041] Further, the curve terminates with an end point. This endpoint is located at the
aperture created by the motor shaft into the wall(s) of the basement duct. As mentioned
above, the motor shaft has to pierce one of the basement duct walls in order to reach
the outlet.
[0042] Each curve, limited by the end point and starting point, resembles substantially
a polynomial curve.
[0043] For each point of the curve, a distance D from that point to the motor axis is defined.
Thus calling w the ordinate or position of the point along the motor axis, where the
"0" (zero) is positioned at the starting point of the curve at the outlet of the basement
and the ordinate axis points towards the motor, the function D(w) is according to
the invention a monotone function and more preferably a decreasing monotone function.
[0044] That is to say that the closer the ordinate or position w of the point to the end
point of the curve is taken, the smaller is the distance between the point of the
curve at that ordinate w and the motor axis, while the closer to the starting point
of the curve such ordinate is, the longer is the distance between the point of the
curve having such ordinate w curve and the motor axis. This function of the distance
of the position of a selected point of the curve from the motor axis versus the position
or ordinate of such selected point of the curve at which the distance is calculated,
as said, is decreasing monotone and therefore there are no changes in the way the
function progresses; there is no possibility for the presence of a flange because
this would cause an increase of the distance curve-axis of the motor after a decrease
of the same, which is not according to the claimed shape of the process duct.
[0045] In this way, the process air duct, in particular in a portion of the process air
duct close to the basement process air outlet, is "smooth" and does not include sudden
variations in its diameter.
[0046] With the term "diameter", not only ducts or apertures having a circular cross section
are meant. In case of non-circular sections, the term "diameter" defines the largest
dimension of their respective cross section along a given plane (for example horizontal).
[0047] The process air substantially flows smoothly through the process air conduit without
any sharp variation in the cross section dimensions in this part of the process air
conduit.
[0048] Tests of the Applicant have shown that the dryer having such a construction of the
basement duct yields a flow of process air considerably improved, increasing the overall
efficiency of both the process air generator and of the fan which moves process air
within the process air conduit.
[0049] According to this aspect, the invention may include, alternatively or in combination,
any of the following characteristics.
[0050] Preferably, said laundry dryer includes a fan apt to circulate said process air into
said process air conduit, said fan being located within said process air conduit and
including an impeller having an air inlet section which is the inlet for the process
air to said impeller and wherein a diameter of said basement process air outlet is
smaller or substantially equal to a diameter of said inlet for the process air to
the impeller.
[0051] The process air conduit advantageously includes a main fan having an impeller which
sucks process air out of the basement to blow it towards the drum. The fan of the
dryer is located inside an impeller housing. In the impeller housing, the impeller
defines an inlet section, which is in other words the section at the inlet of process
air to the impeller.
[0052] Advantageously, said diameter of said basement process air outlet is equal or substantially
equal to a diameter of the air inlet section of said impeller. In this way, all the
impeller is invested by process air and the efficiency of the fan is improved. No
discontinuity is present in the process air conduit, but substantially a single smooth
channel brings process air from the basement to the impeller of the fan.
[0053] Preferably, said impeller housing is in abutment to said basement of said laundry
dryer.
[0054] Preferably, said basement process air duct is inserted for a predefined length in
said impeller housing.
[0055] Moe preferably, said basement process air outlet is positioned substantially in front
of said impeller.
[0056] The air flow coming from the process air generator is directly guided to the impeller,
without any disturbing discontinuities in the air channel in front of the impeller
of the fan, so as to maximize the efficiency of the dryer and minimize its energy
consumption. In addition, the number of components is minimized, avoiding connecting
channels between the various part of the dryer.
[0057] In a preferred embodiment, a family of planes passing through said motor axis and
sectioning said basement process duct portion and said basement process air outlet
in said outer portion forms a family of sections which define a family of curves,
a starting point of each of these curves being located in said basement process air
outlet and an end point of said curve being located at the aperture; and wherein in
all said sections by said family of planes passing through the motor axis, the distance
between a point of each of said curves and said motor axis is a decreasing monotone
function if the position of said point moves from said starting point to said end
point.
[0058] There is therefore not only a single curve which defines a monotone decreasing function
of the distance between a point of the curve and motor axis as a function of the ordinate
of the selected point along the same motor axis, but a plurality of such curves can
be defined in the outer portion of the basement duct. This implies that the duct is
"smooth" substantially in its entirety close to the basement process air outlet.
[0059] Advantageously, said casing includes a rear wall, and said back wall comprises said
impeller housing.
[0060] In this way the number of components of the casing is reduced.
[0061] Preferably, said drying air generator includes a heat pump system comprising a condenser
and an evaporator, wherein said condenser and said evaporator are preferably located
in said basement.
[0062] The heat pump technology allows achievements of increased efficiency in a dryer.
[0063] In a preferred embodiment, said basement includes an upper shell portion and a lower
shell portion, said basement process air duct and basement process air outlet being
formed by the connection between said upper shell portion and said lower shell portion.
[0064] The basement process air duct portion in the basement can be realized for example
in an easy and reliable manner joining together two shell portions so as to form walls
of the basement process air duct.
[0065] Advantageously, said basement is realized in plastic material, and said basement
process air duct is realized integral to said basement.
[0066] It should also be observed that, in the present description and in the attached claims,
the terms "plastic material" and the like, are used to indicate any plastic or synthetic
material, or based on plastic or synthetic material, possibly added with fillers suitable
to improve the functional and robustness characteristics thereof, such as minerals,
textile synthetic fillers and so on and so forth.
[0067] The fact that the basement is realized in plastic allows a minimization of the number
of elements included in the dryer of the invention. Indeed, with a single producing
process, for example with the same molding process, the basement can be realized including
a plurality of additional functional elements for the dryer that do not have to be
realized separately and then assembled, such as the basement process air duct portion
or others, for example the seats for the heat exchangers.
[0068] Preferably, said casing includes a rear wall and said impeller housing is fluidly
connected to a portion of process air conduit located within said rear wall to channel
process air to said drum.
[0069] The air blown by the fan is directed towards the drum. Preferably the number of components
in the casing is reduced and thus the channel directing process air from the fan to
the drum is realized in the rear wall of the dryer.
[0070] Preferably, said fan is located downstream of said process air generator in the direction
of flow of said process air.
[0071] Advantageously, said basement defines a basement plane, in which a first longitudinal
half of the basement and a second longitudinal half of the basement are identifiable
by means of a first plane perpendicular to said basement plane and passing through
a rotational axis of said drum; said basement process air outlet being located within
said second longitudinal half of said basement and said first heat exchanger and said
second heat exchanger are located for the majority of their respective volumes within
said first longitudinal half of said basement.
[0072] In a top view of the dryer, as mentioned, the basement can be considered as "divided"
in two halves by the axis of rotation of the drum. Whether the axis is horizontal
(thus parallel to the basement plane of the dryer) or substantially horizontal or
tilted with respect to the basement plane of the dryer, on a plan view of the basement
the projection of the rotational axis of the drum divides the basement in two halves,
a first or left longitudinal half and a second or right longitudinal half. In other
words, taking another plane which is perpendicular to the basement plane and which
passes through the rotational axis of the drum, this other plane virtually sections
the basement also in two halves. This other plane, when sectioned by a plane parallel
to said basement plane defines a line of division of the basement in two.
[0073] The layout of the heat pump system located in the basement of the dryer of the invention
is the following.
[0074] The first heat exchanger and the second heat exchanger are located within the basement
in the process air conduit and extend for the majority of their respective volume
within the first longitudinal half of the basement, e.g. they are substantially located
for the majority of their respective volumes on the left of the rotational axis of
the drum, i.e. within the first longitudinal half of the basement. The heat exchangers
can be completely contained within the first longitudinal half of the basement or,
alternatively, a part of their volume, the minority part, can also extend within the
second longitudinal half of the basement. Also the exit of process air from the condenser
is located within the first longitudinal half of the basement, at least for most of
its area.
[0075] On the other end, the outlet of process air is located within the second longitudinal
half of the basement, i.e. right of the rotational axis of the drum. Preferably, the
outlet is realized in the rear of the basement, i.e. facing the real wall of the casing.
Thus, in order to channel the process air outside the basement, the basement process
air duct portion extends from the exit of the condenser to the outlet of the basement
starting from the first longitudinal half of the basement and reaching the second
longitudinal half of the basement.
[0076] Preferably, said laundry dryer includes a motor, said motor being apt to rotate said
fan and said drum.
[0077] In order to lower costs, a single motor is present, which drives both the fan and
the drum of the laundry dryer. Preferably, both motor and fan shares the same shaft
and are thus coaxial.
Brief description of the drawings
[0078] Further advantages of the present invention will be better understood with non-limiting
reference to the appended drawings, where:
- Fig. 1 is a perspective view of a laundry dryer realized according to the present
invention;
- Fig. 2 is a perspective view of the laundry dryer of Fig. 1 with an element of the
casing removed for showing some internal components;
- Fig. 3 is a perspective view, in a disassembled configuration, of the basement of
the dryer of Fig. 1 or Fig. 2;
- Fig. 4 is a perspective view of the basement of Fig. 3 with all elements contained
therein removed;
- Figs. 5 is a top view of the basement of Fig. 3;
- Fig. 6 is a lateral view in section of a portion of the basement of Figs. 3-5;
- Figs. 7 is a perspective views in a disassembled configuration, of a portion of the
laundry dryer of Figs. 1 and 2 including the basement of Figs. 3-5;
- Figs. 8a and 8b are two front views of a detail of two different embodiment of the
dryer of the invention;
- Fig. 9 is a rear view of the basement of Figs. 3-5;
- Fig. 10 is a top view of the basement of Figs. 3-5 divided in two;
- Fig. 11 is section of the basement along line A-A of Fig. 9; and
- Fig. 12 is a section of the basement along line B-B of Fig. 9.
Detailed description of one or more embodiments of the invention
[0079] With initial reference to Figs. 1 and 2, a laundry dryer realized according to the
present invention is globally indicated with 1.
[0080] Laundry dryer 1 comprises an outer box or casing 2, preferably but not necessarily
parallelepiped-shaped, and a drying chamber, such as a drum 3, for example having
the shape of a hollow cylinder, for housing the laundry and in general the clothes
and garments to be dried. The drum 3 is preferably rotatably fixed to the casing 2,
so that it can rotate around a preferably horizontal axis R (in alternative embodiments,
rotation axis may be tilted). Access to the drum 3 is achieved for example via a door
4, preferably hinged to casing 2, which can open and close an opening 4a realized
on the cabinet itself.
[0081] More in detail, casing 2 generally includes a front wall 20, a rear wall 21 and two
lateral walls 25, all mounted on a basement 24. Preferably, the basement 24 is realized
in plastic material. Preferably, basement 24 is molded via an injection molding process.
Preferably, on the front wall 20, the door 4 is hinged so as to access the drum. The
casing, with its walls 20, 21, 25, defines the volume of the laundry dryer 1. Advantageously,
basement 24 includes an upper and a lower shell portion 24a, 24b (visible in Figures
3 and 4 detailed below).
[0082] The dryer 1, and in particular basement 24, defines an horizontal plane (X,Y) which
is substantially the plane of the ground on which the dryer 1 is situated, thus it
is considered to be substantially horizontal, and a vertical direction Z perpendicular
to the plane (X,Y).
[0083] Laundry dryer 1 also preferably comprises an electrical motor assembly 50 for rotating,
on command, revolving drum 3 along its axis inside cabinet 2. Motor 50 includes a
shaft 51 which defines a motor axis of rotation M.
[0084] Further, laundry dryer 1 may include an electronic central control unit (not shown)
which controls both the electrical motor assembly 50 and other components of the dryer
1 to perform, on command, one of the user-selectable drying cycles preferably stored
in the same central control unit. The programs as well other parameters of the laundry
dryer 1, or alarm and warning functions can be set and/or visualized in a control
panel 11, preferably realized in a top portion of the dryer 1, such as above door
4.
[0085] With reference to Figure 2, the rotatable drum 3 includes a mantle, having preferably
a substantially cylindrical, tubular body 3c, which is preferably made of metal material
and is arranged inside the casing 2 and apt to rotate around the general rotational
axis R which can be - as said - horizontal, i.e. parallel to the (X,Y) plane, or tilted
with respect to the latter. The mantle 3c defines a first end 3a and a second end
3b and the drum 3 is so arranged that the first end 3a of the mantle 3c is faced to
the laundry loading/unloading opening realized on the front wall 20 of the casing
2 and the door 4, while the second end 3b faces the rear wall 21.
[0086] Drum 3 may be an open drum, i.e. both ends 3a and 3b are opened, or it may include
a back wall (not shown in the appended drawings) fixedly connected to the mantle and
rotating with the latter.
[0087] In order to rotate, support elements for the rotation of the drum are provided as
well in the laundry of the invention. Such support elements might include rollers
at the front and/or at the back of the drum, as well as or alternatively a drum shaft
connected to the rear end of the drum (shaft is not depicted in the appended drawings).
In Fig. 2, for example, a roller 10 connected to the basement via a bracket 101a as
well as a roller 10 connected to the rear wall 21 via a boss 101 is depicted. Any
support element for the rotation of the drum around axis R is encompassed by the present
invention.
[0088] Dryer 1 additionally includes a process air circuit which comprises the drum 3 and
a process air conduit 18, depicted as a plurality of arrows showing the path flow
of a process air stream through the dryer 1 (see Figures 3 and 4). In the basement
24, a portion of the process air conduit 18 is formed by the connection of the upper
shell 24a and the lower shell 24b. Process air conduit 18 is preferably connected
with its opposite ends to the two opposite sides of drum 3, i.e. first and second
rear end 3a,3b of mantle 3c. Process air circuit also includes a fan or blower 12
(shown in Figs. 3, 6, 7 and 8a-8b).
[0089] The dryer 1 of the invention additionally comprises a process air generator, in the
depicted embodiment a heat pump system 30 including a first heat exchanger (called
also condenser) 31 and a second heat exchanger (called also evaporator) 32 (see figure
3). Heat pump 30 also includes a refrigerant closed circuit (partly depicted) in which
a refrigerant fluid flows, when the dryer 1 is in operation, cools off and may condense
in correspondence of the condenser 31, releasing heat, and warms up, in correspondence
of the second heat exchanger (evaporator) 32, absorbing heat. A compressor 33 receives
refrigerant in a gaseous state from the evaporator 32 and supplies the condenser 31,
thereby closing the refrigerant cycle. In the following the heat exchangers are named
either condenser and evaporator or first and second heat exchanger, respectively.
More in detail, the heat pump circuit connects via piping 35 (see Fig. 3) the second
heat exchanger (evaporator) 32 via the compressor 33 to the condenser 31. The outlet
of condenser 31 is connected to the inlet of the evaporator 32 via an expansion device
(not visible), such as a choke, a valve or a capillary tube.
[0090] Preferably, in correspondence of evaporator 32, the laundry dryer 1 of the invention
may include a condensed-water canister (also not visible) which collects the condensed
water produced, when the dryer 1 is in operation, inside evaporator 32 by condensation
of the surplus moisture in the process air stream arriving from the drying chamber
(i.e. drum) 3. The canister is located at the bottom of the evaporator 32. Preferably,
through a connecting pipe and a pump (not shown in the drawings), the collected water
is sent in a reservoir located in correspondence of the highest portion of the dryer
1 so as to facilitate a comfortable manual discharge of the water by the user of the
dryer 1.
[0091] The condenser 31 and the evaporator 32 of the heat pump 30 are located in correspondence
of the process air conduit 18 formed in the basement 24 (see Figure 3).
[0092] In case of a condense-type dryer - as depicted in the appended figures - where the
air process circuit is a closed loop circuit, the condenser 31 is located downstream
of the evaporator 32. The air exiting the drum 3 enters the conduit 18 and reaches
the evaporator 32 which cools down and dehumidifies the process air. The dry cool
process air continues to flow through the conduit 18 till it enters the condenser
31, where it is warmed up by the heat pump 30 before re-entering the drum 3.
[0093] It is to be understood that in the dryer 1 of the invention, an air heater, such
as an electrical heater, can also be present, in addition to the heat pump 30. In
this case, heat pump 30 and heater can also work together to speed up the heating
process (and thus reducing the drying cycle time). In the latter case, preferably
condenser 31 of heat pump 30 is located upstream the heater. Appropriate measures
should be provided to avoid the electric heater to fuse plastic components of the
dryer 1.
[0094] Further, with now reference to Figures 4 and 5, in the basement, the process air
conduit 18 includes a duct formed by the upper and the lower shells 24a, 24b, having
an inlet 19in from which process air is received from the drum 3 and an outlet 19
to channel process air out of the basement 24. Between inlet 19in and outlet 19, the
duct is formed, preferably as two single pieces joined together and belonging to the
upper and lower shell 24a, 24b, and including a first and a second portion 28 and
29. In the first portion 29 of this duct, seats 29s are formed for locating the first
and the second heat exchangers 31, 32. Preferably, first and second heat exchanger
31, 32 are placed one after the other, the first heat exchanger 31 being downstream
in the direction of flow of the process air the second heat exchanger 32. Further,
the second portion 28 channels the process air exiting from the first heat exchanger
31 towards the basement outlet 19.
[0095] The second portion 28 thus starts at the location of an exit 28in of the first heat
exchanger 31, considered as the location of a plane sectioning the duct portion 28
and substantially in contact with a surface of the first heat exchanger 31 from which
process air exits.
[0096] Preferably, the exit 28in may be defined on a plane perpendicular to the basement
plane (X,Y), e.g. on a vertical plane.
[0097] Furthermore, preferably also the outlet 19, defined as the area at which the air
exits the basement, defines in turn a plane substantially perpendicular to the basement
plane, e.g. a vertical plane.
[0098] Considering now a first plane P1 perpendicular to the basement plane (X,Y) and embedding
the rotational axis R of the drum 3, this first plane P1 divides the basement 24 in
two halves, called, with now reference to Figures 4 and 5, basement first or right
half 24 first half and basement second or left half 24 second half. These two halves
24 first half and 24 second half need not to be identical in dimension (i.e. they
are not mathematical halves), however in the present depicted embodiment P1 also embeds
a first - longitudinal - centerline H1 of the basement. Furthermore, still in the
depicted embodiment, P1 is a vertical plane.
[0099] On the first half of the basement, 24 first half, the portion 29 of the duct is positioned,
where also the first and the second heat exchanger 31, 32 of heat pump 30 are located.
The heat exchanger can be completely contained within the first half of the basement
24 first half or they can also extend beyond the limit defined by the first plane
P1. If a portion of the first and/or second heat exchanger 31, 32 is also located
within the second half of the basement 24 second half, this portion is the minority
of the whole volume occupied by the first and/or second heat exchanger 31, 32.
[0100] On the second half of the basement 24 second half, preferably the compressor 33 is
located. More preferably, also the motor 50 is located in this second half. Furthermore,
as mentioned, main fan 12 is part of the process air conduit 18 and it is placed substantially
in front of in proximity of the basement outlet 19 so that it blows the air exiting
the basement 24 towards drum 3. The outlet and the main fan are thus located in the
basement second half 24 second half (although fan 12 does not properly belong to the
basement, it belongs to that part of the casing which is divided by plane P1 where
the second half of the basement is contained).
[0101] Preferably, motor 50 including shaft 51 defining motor axis M has the motor axis
substantially parallel to the first plane P1 (see Figure 5).
[0102] Preferably, motor shaft 51 of motor 50 drives both the drum 3 and the fan 12 into
rotation, i.e. preferably, motor shaft 51 is also the shaft of fan 12, which is located
in proximity of outlet 19, preferably facing the latter. In particular, fan 12 includes
an impeller 12a whose blades are rotated by the rotation of shaft 51. In order to
rotate both the drum and the impeller 12a, the shaft 51 exits the basement 24 at least
for a portion through outlet 19.
- Fan 12 blows the process air exiting the basement 24 through outlet 19 into the drum
3, preferably through a passage, not shown, part of the process air circuit 18, formed
within the rear wall 21.
[0103] Advantageously, the motor shaft 51 is substantially perpendicular to the surface
defined by outlet 19 and it passes through its center. Alternatively, the motor shaft
51 and the surface defined by outlet 19 can be slightly inclined and/or the shaft
passes in proximity of the center of outlet 19. The center is defined as the intersection
of two axis of the outlet surface. In order to exit through the outlet 19, the shaft
51 has to create a through hole or aperture 26 in the walls 28w of the duct 28, as
better visible in Fig. 6.
[0104] Again with reference to Figs. 4 and 5, considering now a second plane P2, perpendicular
to P1 and to the basement plane (X,Y) and passing through a second centerline H2 of
the basement 24, perpendicular to the first centerline H1, the basement 24 is divided,
by a combination of the first and the second plane P1, P2, in four quarters Q1 - Q4.
The quarters are numbered in a clockwise manner, the first quarter Q1 being the rearmost
quarter of the first half of the basement 24 (e.g. the quarter facing the rear wall
21), the second quarter Q2 being the rearmost quarter of the second half of the basement
24, the third quarter Q3 the foremost quarter (e.g. the quarter facing the front wall
20) of the second half of the basement and the last fourth quarter Q4 the foremost
quarter of the first half of the basement 24.
[0105] It can be therefore seen that the heat exchangers 31, 32 and the duct portion 29
are substantially contained for the majority of their volume within the fourth quarter
Q4, the second heat exchanger closer to the front wall 20 than the first heat exchanger
31; preferably compressor 33 is contained within the third quarter Q3, and the outlet
19 of basement 19 is located in the second quarter Q2, preferably facing rear wall
21 of casing 2.
[0106] Motor 50 is preferably contained within the second quarter Q2 as well and its shaft
51 which extends in such a way that it sticks out from the outlet 19, i.e. it exits
the basement 24 with one of its ends through the basement outlet 19.
[0107] The duct portion 28 extends from the air exit of the compressor, 28in, which is located
within the first quarter Q1 preferably close to the boundary with the fourth quarter
Q4, i.e. close to centerline H2, to the outlet 19 of the basement, located in the
second quarter Q4.
[0108] Preferably, but not necessarily, the planes containing the exit 28in and the outlet
19 are substantially parallel to each other and even more preferably they are both
parallel to P2.
[0109] The duct portion 28 therefore has to comprise at least one curve or bend in order
to extend from the first to the second quarter. Furthermore, duct portion 28 includes
walls 28w which form and delimit the duct portion itself. The configuration of walls
28w can change also along the extension of the duct, for example close to the outlet
19, the section of the duct portion 28 becomes substantially circular and thus walls
28w delimiting the duct 28 forms in section a circumference. However in other parts
of the duct, the walls can have a different geometry, for example having flat portions.
Any embodiment of the geometrical configuration of walls 28w is encompassed in the
present invention.
[0110] Preferably, walls 28w includes a first and second lateral walls 28w1 and 28w2, which
are each separated in half and each of the halves is integrally formed with the upper
or lower shell 24a, 24b. That is to say, the upper shell 24a includes a part of first
lateral wall 28w1 and a part of second lateral wall 28w2, both parts integrally formed
with the upper shell 24a, while the lower shell 24b includes the remaining part of
first lateral wall 28w1 and remaining part of second lateral wall 28w2, both remaining
parts integrally formed with the lower shell 24b.
[0111] Referring now to Figs. 6 and 7, in the depicted laundry dryer 1, the rear wall 21
of the cabinet 2 forms a rear bulkhead 60 which faces the rear end 3b of the drum
3, and it is advantageously realized as a single, unitary, piece. Preferably, the
rear wall 21 of the cabinet 2 includes also a fan housing 150, covered by a cover
61 which is attached, in a detachable manner, to the rear bulkhead 60. Thus a fan
aperture 61a is formed in the bulkhead 60 which is closed by the cover 61, fan aperture
used to access the fan 12, and in particular the impeller 12a of the same. The aperture
61a is located substantially below the location of the drum 3 and faces the interior
of the casing 2, in this example, the basement 24 and more preferably an outlet 19
of the air from the basement 24.
Furthermore, as illustrated in the above example, the whole fan housing 150 is realized
within the rear wall 21 and it is composed by a first cup-shaped portion 142 (which
belongs to the rear bulkhead 60) and the cover 61.
The first cup-shaped face 142 is provided with a through opening 151in, in the example
shown circular, for housing the relevant shaft 51 of the impeller 12a. Of course,
the impeller 12a is housed in the housing 150. The same opening 151in is also used
for the inlet air to the fan 12. Therefore, in the process air conduit 18, air exits
the basement from outlet 19, where it has been heated and/or dried by the drying air
generator - heat pump 30 -, and enters into the fan housing 150. From the fan housing
150, which is a closed element being the fan aperture 61a closed by cover 61, a conduit
portion formed by the rear bulkhead 60 and the cover 61 channels air into the drum
3.
[0112] Shaft 51 thus exits the basement via the outlet 19. The arrangement of impeller 12a
and outlet 19 is as follows. Preferably impeller is located in front of outlet 19.
More preferably, outlet and impeller are concentric, i.e. they have the same center
which preferably also coincides with the axis of the motor M. This situation is clearly
depicted in Figs. 6 and 8a-8b.
[0113] The diameter Dia1 of the outlet 19 can be equal or smaller than the diameter Dia2
of the inlet of process air to the impeller 12a. The inlet of process air to the impeller
in this embodiment coincides to the inlet 150in of fan housing 150. In general, the
inlet of air in the impeller has a diameter Dia2 which coincides with the internal
diameter of the impeller's blades.
[0114] In case the outlet 19 and/or the inlet 150in is/are not circular, the diameter is
considered as the biggest dimension of the outlet/inlet along a horizontal plane.
[0115] In Figs. 8a and 8b the two different embodiments are shown: in Fig. 8a, the diameter
Dia1 of the outlet 19 is smaller than the diameter Dia2 of the air inlet of impeller
12a. In Fig. 8b the two diameters Dia1 and Dia2 of the outlet 19 and inlet of impeller
12a preferably coincide. In this way, the impeller 12a is used in the most efficient
way and all process air coming from the basement 24 impinges on the impeller inlet
section.
[0116] Furthermore, in order to better channel process air to the impeller 12a, a portion
of the duct 28 is inserted in the fan housing 150, in other words, as shown in Fig.
6, the outlet 19 of the basement is located within the fan housing 150.
[0117] Still with reference to Fig. 6, a small channel 14 can be realized within the fan
housing 150 to introduce air from the inlet 150in to the blades of the impeller 12a.
[0118] Considering now the front view of the basement 24 Fig. 9, a plane perpendicular to
the basement plane (X,Y) and passing through the motor axis M is visualized and named
PH. This plane divides the basement process air duct 28 in two parts called 28inner
and 28outer. Being the outlet 19 part of the duct 28, PH also divides the outlet 19
in two, in case of a circular outlet 19 the two parts are two halves of a circumference.
In Fig. 10, a top view of the basement 24 is shown divided in the upper and lower
shells 24a, 24b. In this top view, the motor axis M and the plane PH coincide. The
outer portion 28outer of the duct 28 sectioned by the plane PH is the portion of duct
28 that in this figure starts at motor axis M and extends towards the bottom of the
Figure 10, while the inner part 28inner is the portion of duct 28 that starts at the
motor axis and extends towards the top of the Figure 10. Regardless of the orientation
of the drawing, the inner portion 28inner is the portion of duct that passes through
the centreline H1 (see Fig. 4) of the basement 24, while the outer portion 28outer
does not. The outer portion 28outer is located only within the basement first half
24 first half, while the inner portion 28inner extends through the first and the second
half of the basement. Furthermore, the outer portion 28outer only includes a part
of the inner curve 28a, while the inner portion 28inner includes the outer curve 28a
and possibly also part of the inner curve 28b.
[0119] In the front view of Fig. 9, the outer portion 28outer is substantially half of a
cylindroid-shaped mantel which terminates with a bottom end.
[0120] With still reference to Fig. 9, a further plane is considered, PZ, again passing
through the motor axis M, but at any angle with the basement plane (X,Y). This plane
PZ, two of which are shown in Fig. 9, sections the outer portion 28outer of the duct
28. Each section of the outer portion 28outer defines a curve C, which is the configuration
of the sectioned walls 28w in the sectioned plane. A section along a first plane PZ
of line A-A of Fig. 9 and a section along a second plane PZ of line B-B of Fig. 9
are depicted in Figs. 11 and 12, respectively. Further, also Fig. 10 is such a section
along a plane PZ, in this case with a plane PZ passing through the motor axis M and
parallel to the basement plane (X,Y).
[0121] As better visible in the enlarged details of Figs. 11 and 12, the curve C of each
section along a plane PZ has a starting point Pin which is positioned on the outlet
19 of the basement 24. Further, each curve C (one curve formed by each section) has
an end point Pend, located in proximity of the motor axis M, at aperture 26 formed
by the motor shaft 51 on the walls 28w of the outer portion 28outer of duct 28.
[0122] The curve C of each section is delimited thus by these two points Pin and Pend and
it extends for a given length along the motor axis M. For each selected point of the
curve C in a section, a distance between the selected point and the motor axis M is
defined. These distances D1....Di....DN for different points 1...i...N having a different
location along the moto0r axis Mare depicted with a plurality of arrows in Figs. 11
and 12.
[0123] The shape of the outer portion 28outer of the duct 18 is according to the invention
as follows. The distance between the starting point Pin and the motor axis is the
longest distance among all distances D1....Di....DN. The distance between the motor
axis M and the end point Pend is the shortest distance among all distances D1....Di....DN.
The distance between a point of the curve having ordinate w, where w is a point on
the motor axis M and the 0 is located at the starting point Pin, the direction of
the ordinate axis w being towards the end point Pend, is a monotone function of the
ordintale w of the point and in particular a decreasing monotone function:

[0124] Preferably, this is valid for all planes PZ sectioning the outer portion 28outer
defining a C curve, not only for a single plane PZ. In each curve C obtained by the
section with a plane PZ, the distance between a point in the curve and the motor axis
is a decreasing function when the point considered has a position which moves its
ordinate starting from the outlet 19 and going towards the motor engine 50.
[0125] A smooth duct 28 is so realized, which gently channels air towards the outlet t19.
1. A laundry dryer (1) including:
- a dryer casing (2) having a front wall (20), a rear wall (21), lateral walls (25),
and a basement (24) defining a basement plane (X,Y);
- a drum (3) rotatably accommodated within said casing (2) and accessible via a door
connected to said front door (4);
- a process air conduit (18) wherein drying process air is apt to flow, said process
air conduit (18) being connected to said drum (3) so that said process air flows therethrough;
- a process air generator (30), apt to generate drying process air, said process air
generator (30) being located within said process air conduit (18);
- said process air conduit (18) including a basement process air duct (28) formed
in said basement (24), said basement process air duct (28) having walls (28w) and
including a basement process air outlet (19) where process air exits said basement
(24),
- a motor (50) having a shaft (51) defining a motor axis (M), said motor axis passing
through an aperture (26) provided in the basement process air duct (28) and substantially
at or in proximity of a center of said basement process air outlet (19);
- wherein a plane (PH) perpendicular to said basement plane (X, Y) and sectioning
said basement (24) along said motor axis (M) divides said basement process air duct
(28) in an outer (28outer) and in an inner portion (28inner), said outer portion (28outer)
being the portion closer to a lateral wall (25) of the casing (2);
- wherein a section by a plane (PZ) passing through said motor axis (M) and sectioning
said basement process duct portion (28) and said basement outlet (19) in said outer
portion (28outer) defines a curve (C), a starting point (Pin) of said curve (C) being
located at said basement process air outlet (19) and an end point (Pend) of said curve
(C) being located at said aperture (26); and
- wherein in said section by said plane (PZ) passing through the motor axis, the distance
(D1,..., Di,....,DN) between a point of said curve (C) and said motor axis (M) is
a decreasing monotone function if the position of said point moves from said starting
point (Pin) to said end point (Pend).
2. The laundry dryer according to claim 1, including a fan (12) apt to circulate said
process air into said process air conduit (18), said fan (12) being located within
said process air conduit (18) and including an impeller (12a) having an air inlet
section (150in) which is the inlet for the process air to said impeller (12a) and
wherein a diameter (Dia1) of said basement process air outlet (19) is smaller or substantially
equal to a diameter (Dia2) of said inlet (150in) for the process air to the impeller
(12a).
3. The laundry dryer according to claim 1 or 2, wherein said casing includes an impeller
housing (150) in which an air channel (14) to channel said process air to said impeller
(12a) is defined, said air channel (14) having as inlet an air inlet section (150in)
which is the inlet for the process air to said impeller (12a).
4. The laundry dryer according to claim 3, wherein said impeller housing (150) is in
abutment to said basement (24) of said laundry dryer (1).
5. The laundry dryer (1) according to any of the preceding claims, wherein a family of
planes (PZ) passing through said motor axis (M) and sectioning said basement process
duct portion (28) and said basement process air outlet (19) in said outer portion
(28outer) forms a family of sections which define a family of curves (C), a starting
point (Pin) of each of these curves being located in said basement process air outlet
(19) and an end point (Pend) of said curve (C) being located at the aperture (26);
and wherein in all said sections by said family of planes passing through the motor
axis, the distance (D1,..., Di,....,DN) between a point of each of said curves (C)
and said motor axis (M) is a decreasing monotone function if the position of said
point moves from said starting point (Pin) to said end point (Pend).
6. The laundry dryer (1) according to any of the preceding claims when dependent on claim
2, wherein said basement process air duct (28) is inserted for a predefined length
in said impeller housing (150).
7. A laundry dryer according to claim 6, wherein said basement process air outlet (19)
is positioned substantially in front of said impeller (12a).
8. A laundry dryer (1) according to any of the preceding claims when dependent on claim
2, wherein said casing (2) includes a rear wall (21) and said rear wall (21) of the
casing (2) comprises said impeller housing (150).
9. A laundry dryer (1) according to any of the preceding claims, wherein said process
air generator (30) includes a heat pump system comprising a condenser (31) and an
evaporator (32), said condenser (31) and said evaporator (32) being located in said
basement (24).
10. The laundry dryer (1) according to any of the preceding claims, wherein said basement
(24) includes an upper shell portion (24a) and a lower shell portion (24b), said basement
process air duct (28) and said basement process air outlet (19) being formed by the
connection between said upper shell portion (24a) and said lower shell portion (24a).
11. The laundry dryer (1) according to any of the preceding claims, wherein said basement
(24) is realized in plastic material and said basement air duct (28) is realized integral
to said basement (24).
12. The laundry dryer (1) according to any of the preceding claims when dependent on claim
2, wherein said casing (2) includes said rear wall (21) and said impeller housing
(150) is fluidly connected to a portion of said process air conduit (18) located within
said rear wall (21) of the casing (2) to channel process air to said drum (3).
13. The laundry dryer (1) according to any of the preceding claims, wherein said fan (12)
is located downstream of said process air generator (30) in the direction of flow
of said process air.
14. The laundry dryer (1) according to any of the preceding claims when dependent to claim
4, wherein said basement process air duct (28) includes a duct portion which connects
an exit of said process air generator (30) to said basement process air outlet (19)
and wherein the diameter (D1) of said basement process air outlet (19) is the smallest
dimension of said basement process air duct (28).
15. The laundry dryer (1) according to any of the preceding claims when dependent on claim
9, wherein said basement (24) defines a basement plane (X,Y) and in said basement
(24) a first longitudinal half (24 first half) of the basement (24) and a second longitudinal
half (24 second half) of the basement (24) are identifiable by means of a first plane
(P1) perpendicular to said basement plane (X,Y) and passing through a rotational axis
(R) of said drum (3); said basement process air outlet (19) being located within said
second longitudinal half (24 second half) of said basement (24) and said first heat
exchanger (31) and said second heat exchanger (32) are located for the majority of
their respective volumes within said first longitudinal half (24 first half) of said
basement (24).