TECHNICAL FIELD
[0001] The present application relates generally to warewash machines of the commercial
type and, more particularly, to a commercial warewash machine with water soiling level
detection.
BACKGROUND
[0002] Modern commercial warewash equipment uses internally re-circulated water during the
washing process and introduces clean hot water during the rinsing and sanitization
processes. The soil level of the internally re-circulated water increases as dirty
ware (e.g., dishes, cutlery, pots and pans) enters the machine over the course of
an operational shift. If the soil concentration reaches a critical level, the likelihood
of soil re-deposition on to the ware increases.
[0003] Currently, the operator is primarily responsible to identify the issue of soil re-deposition
and take corrective actions. Typical corrective actions may include rerunning ware,
pausing the operation to partially drain the machine tank or tanks, and pausing the
operation of the machine to clean the strainer/filters.
[0004] Ideally, the warewash machine would have the capability to monitor its own soil level
and take corrective actions (within a range of soil levels) without the interaction
of the operator and reduction in productivity.
[0005] A known approach to sense the level of soil in liquid using optical methods is the
turbidity sensor. The use of turbidity sensors in residential dishwashers is commonplace
and the technology is readily available. For instance,
US 2006/021637 A1 discloses a sump assembly in a dishwasher comprising a sensor for measuring the turbidity
of the washing water discharged to the outside of the dishwasher. However, the migration
of turbidity sensors to commercial warewash equipment has been slow due to challenges
unique to their applications. For example, commercial warewash equipment operates
with a much broader range of acceptable soil loads during the washing process. Existing
turbidity sensors lack the dynamic range of operation for use in commercial warewash
equipment. Additionally, existing turbidity control logic does not adequately optimize
the performance of a commercial dishwasher due to the different nature of the machine
cycles. Moreover, commercial warewash equipment operates with higher wash volumes
and flow rates resulting in a significantly more turbulent environment in the wash
tank(s). The placement of turbidity sensors in the prior art (e.g., in the tank or
in line with wash water recirculation flow) does not allow for suitably accurate readings
of soil level due to turbulence/bubbles, etc. in the wash water.
[0006] Accordingly, it would be desirable and advantageous to provide a soil sensing system
that is more suited to the commercial warewash machine environment.
SUMMARY
[0007] According to the invention, a warewash machine according to independent claim 1 and
a method of detecting soiling of liquid in a tank according to independent claim 12
are provided. Preferred embodiments of the invention are subject-matter of the dependent
claims.
BRIEF DESCRIPTION OF DRAWINGS
[0008]
Fig. 1 is a schematic diagram of one embodiment of a warewash machine incorporating
the soil level detection system;
Fig. 2 is a schematic diagram of the soil level detection sensor arrangement;
Fig. 3 is an alternative embodiment of a warewash machine incorporating the soil level
detection system; and
Fig. 4 is a timing diagram for an exemplary cycle of the machine of Fig. 3.
DETAILED DESCRIPTION
[0009] Referring to Fig. 1, in one implementation, the soil detection system is implemented
in the context of a conveyor-type dishwasher 10 in which items to be washed are moved
(e.g., right to left in Fig. 1 via a conveyance mechanism 12) through a housing 14
having multiple spray zones 16, 18, 20 and 22 and, in some cases, a drying zone 24.
The conveyance mechanism 12 may be on suitable type, such as a continuous belt-type
with ware receiving slots or a reciprocating type configured to move ware baskets
containing ware.
[0010] By way of example, spray zone 16 may be a pre-wash zone, zone 18 may be a main wash
zone, zone 20 may be a hot post-wash zone (also known as a power rinse zone) and zone
22 may be a final rinse zone. Additional spray zones could be included, or a lesser
number of spray zones implemented. As shown, the pre-wash zone 16 includes an associated
water tank 26, pump 28 and line 30 forming a recirculation path in which liquid is
delivered from the tank 26 to nozzles 32 (e.g., located in upper and lower laterally
extending spray arms) for spraying, and the sprayed liquid collects in the tank 26
for recirculation. Wash zone 18 includes a similar tank 34, pump 36, line 38 and spray
nozzles 40 forming a recirculation flow path. Likewise, post-wash zone 20 includes
a similar tank 42, pump 44, line 46 and nozzles 48 forming a recirculation flow path.
Tank 42 is shown with an associated heating element 50 for heating the tank water,
and one or both of tanks 34 and 26 could include a heating element as well if desired.
[0011] The final rinse zone 22 includes an associated booster heater tank 52 that receives
water from a fresh water input source 54 through a valve 56 or other feed structure
(e.g., a pump). The booster tank 52 is connected to deliver water via line 58 to nozzles
60 in the final rinse zone 22, and includes a heating element 62 for heating the rinse
water. The booster tank could include an associated delime system.
[0012] One or more of the tanks 26, 34 and 42 may have an associated fresh water feed line
70, 72, 74 and related valve 76, 78, 80 to control delivery of fresh water into the
tank from a fresh water line 82 if desired.
[0013] The drying zone 24 includes a blower 84, which typically includes an associated heater,
for blowing hot air onto the wares after final rinsing.
[0014] The final-rinse system may include an associated rinse aid supply 90 and pump 92
for delivering rinse aid to the booster 52, or alternatively to the outfeed line of
the booster, in a metered manner. The main wash zone may include an associated detergent
supply 96 and associated pump 98 for delivering detergent to the tank 34, or aleternatively
directly into the line 38, in a metered manner. Other forms of detergent supply may
be used, such as manual placement of a block/solid type detergent product. A controller
100 is provided for operating the various pumps, valves, conveyor and blower in accordance
with one or more programmed cleaning sequences.
[0015] In order to address the limitations of the prior art as it applies to commercial
warewash machines both the dynamic range of the turbidity sensor should be increased
and the position of the sensor be arranged to accommodate the higher level of turbulence
within commercial machines. In regard to sensor position, each of the tanks 26, 34,
and 42 may include an associated drain system (not shown in Fig. 1) enabling the tank
to be drained, either partially or fully, in a controlled manner. By way of example,
reference is made to Fig. 2 in which an exemplary tank drain system 102 is shown.
The drain system includes a piping, tubing or hosing line 104 that connects to an
outlet 106 of the tank and extends to a sensor assembly 108 that utilizes, in one
example, a clear square tubing 110 that has an associated sensor module 112 mounted
thereto. The sensor module 112 includes a light emitting element 114 (e.g., one or
more LEDs) on one side of the tube 110 and a light receiving element 116 (e.g,. one
or more phototransistors) on the opposite side of the tube 110. The lower end of the
sensor assembly is connected to drainage piping or tubing 118 that leads to a facility
drain. A valve 120 may be used to control flow along the drain path, but in other
embodiments a pumped drain system could be employed. While the illustrated sensor
assembly 108 is shown in line with the primary drain path of the tank, the sensor
assembly could, alternatively, be connected in parallel with the primary drain path
(e.g., per dashed line configuration 122). Interface connectors 124 and 126 (e.g.,
round to square transition couplers with associated clamps) may be provided for interconnecting
the sensor assembly in the drain path as shown. The sensor elements include associated
leads 128 and 130 that connect back to the controller 100 and power as needed. Additional
electronic control circuitry may be associated with the sensor elements as needed.
[0016] An alternative sensor arrangement could include multiple LED-phototransistor pairs
arranged or spaced apart vertically from each other such that each pair is positioned
for detection of soil level at a different height in the detection zone. For example,
an implementation having three or more vertically spaced pairs could be beneficial
in identifying floating and settling particles. Specifically, assume that the turbidity
of a water sample is initially determined and that over time the turbidity indicated
by the mid-height sensor pair is reflects that the water sample clears up. If the
turbidity indicated by the LED-phototransistor pair below the mid-height pair increases,
a conclusion can be drawn that particles are settling. The rate of settling may correspond
to the size or density of such particles, enabling particle size to be used as a factor
in machine control. Alternatively, if the turbidity indicated by the LED-phototransistor
pair above the mid-height pair increases, a conclusion can be drawn that particles
are floating.
[0017] Using the suggested sensor positioning, valve or pump cycles may be used to collect
a sample of the tank water sample at predetermined intervals. By way of example, the
machine controller 100 generates a tank water sample signal and a sample of the tank
water is gravity fed by opening the valve 120 (or fed by a pump by operation of the
pump) to the sensor assembly 108. A fresh tank sample may be obtained by momentarily
opening the valve or cycling a pump. The water sample is now within the sensor assembly.
A sample settling time may be applied prior to triggering the sensor components for
monitoring. It is advantageous to allow the sample to settle for a short period of
time to allow bubbles to escape and larger particles to settle or float. The light
emitting element is energized and the output level of the light receiver monitored
to determine turbidity of the water sample. An evaluation can be made by the controller
100 to determine whether any action is necessary based upon the determined turbidity
or soiling level. These actions may repeated as often as desired and in sequences
as determined appropriate for a given machine type.
[0018] Due to the range of soil encountered in a commercial warewash machine, a typical
prior art sensor system would typically have adequate resolution at very low levels
of concentration and reach saturation well before the highest acceptable levels of
soil were reached for a commercial machine. If a single higher intensity turbidity
sensor would be used, meaningful data would be lost at medium or low soil levels.
In order to address this problem, varying the energization level of the light emitting
element is employed.
[0019] In one embodiment, a stepped light intensity technique is used. In one implementation,
the stepped light intensity is achieved by applying stepped energization levels for
the light emitting element (e.g., applying stepped voltage levels). In an alternative
implementation, the stepped light intensity is achieved by using multiple light emitting
elements (e.g., LEDs) and energizing less of the elements at lower steps and more
of the elements at higher steps. In this regard, a "light emitter" may be made up
of a single light element or multiple light elements and, in the latter case, the
energization of the light emitter may, in certain implementations, be varied by energizing
different numbers of the light elements making up the light emitter. The following
is a description of an exemplary application/operation. Other configurations may be
utilized to produce similar results.
[0020] The light emitting element 114 illuminates. The light travels through the water sample
to the light receiver 116. The more soiled the water, the less light transmitted to
the light receiver 116. The light receiver 116 (e.g., a phototransistor) outputs a
voltage proportional to the light received and, therefore, proportional to the water's
soil level. As the soil level increases, the voltage increases. Alternatively, the
electronics could be set up so that as the soil level increases, the voltage decreases.
In either case, a proportional relationship is the result.
[0021] A low light emitter intensity accurately allows the sensing of low soil levels but
does not allow the accurate sensing of high soil levels. At high soil levels, the
low light emitter intensity causes the sensor to saturate (reaches maximum voltage
level) making it impossible to determine the higher soil levels. Conversely, a high
light emitter intensity accurately allows the sensing of high soil levels but does
not allow the accurate sensing of low soil levels. At lower soil levels, the high
light emitter intensity causes the sensor to reach minimum voltage level (near 0 volts)
thereby not being able to determine the lower soil levels. The solution is a sensor
arrangement that puts out different intensities of illumination, to accurately sense
different soil levels.
[0022] In one implementation of the stepped approach, 3 illumination intensities, low, medium,
and high are used. Through experimentation, this has been adequate to sense required
soil levels, though some applications and soil levels may require a higher or lower
number of intensities.
[0023] The controller 100 may be configured to select which intensity to use for the machine.
Specifically, as each intensity level (low, medium, high) is illuminated, the voltage
output level of the light receiver 116 is captured and stored. These voltage output
levels are compared and the intensity level that results in the light receiver voltage
level closest to midrange of the light receiver is chosen for use. By way of example,
and assuming use of a light receiver with a midrange voltage output of two volts,
once soiled water has been delivered into the sensor assembly and, if appropriate
the settling time has passed, the controller 100 effects energization of the light
emitter 114 at the low intensity, and the light receiver voltage output is 3.8 volts.
The light emitter is next energized at the medium intensity and the light receiver
voltage output is 3.5 volts. The light emitter is next energized at the high intensity
and the light receiver voltage output is 1.9 volts. Since the high intensity level
results in the light receiver voltage output level that is closest to 2 volts, the
controller 100 selects the high intensity level energization for use in machine control.
A high intensity lookup table (e.g., stored in memory of the controller 100) may then
be used determine any machine action necessary for the 1.9 volt output level of the
light receiver 116.
[0024] In the above example, if the low intensity energization level resulted in the light
receiver output that was closest to 2 volts, the controller would use that energization
level for machine control and refer to a low intensity lookup table to determine any
machine action necessary. Likewise, if the medium intensity energization level resulted
in the light receiver output that was closest to 2 volts, the controller would used
that energization level for machine control and refer to a medium intensity lookup
table to determine any machine action necessary. The look-up tables can be established
in accordance with a calibration sequence for the sensor assembly, which could be
implemented prior to mounting of the sensor assembly on the machine, or afterward.
In the latter case, the calibration sequence could be incorporated into the program
of the controller 100.
[0025] In this manner, machine control based upon water soiling level can be more effectively
maintained for low, medium and high soiling levels.
[0026] In another embodiment, varying of the light emitter energization level may be achieved
by use of a ramped energization of the light emitter. For example, a complete and
continuous range of light intensities from a very low level that can just produce
a weak signal at the light receiver through very clear wash water to a very high intensity
that can easily penetrate very heavily soiled water may be implemented. A sensor arrangement
that uses the described ramped light intensity may use a light emitter 114 (e.g.,
LED emitter) that is driven by a voltage ramp that causes light intensity levels of
a range greater than needed for the expected range of turbidity to allow for ageing
and buildup on the sample tube. The light receiver 116 receives the light that has
been attenuated by the fluid in the sample tube 110 and produces a signal that is
compared to a predetermined reference value or set threshold value (e.g. as determined
by a calibration sequence). When the ramp driven light emitter 114 reaches an intensity
that causes the light receiver output to equal the reference/threshold value, a comparison
circuit switches and captures the analog value of the voltage ramp at that instant.
The value of the voltage ramp at that time is proportional to the turbidity level
of the fluid in the sample tube. The captured turbidity value is then filtered and
can be an input to the machine logic control system (e.g., used to reference a look-up
table to determine responsive machine actions to be taken). The repetition rate of
the turbidity sampling process can be changed for various applications. If the desire
is to quantify particles suspended in the liquid sample then a high sampling rate
on the order of several hundred samples per second using the appropriate filtering
may be used. If the interest is only in the average turbidity, a slower sampling rate
on the order of several samples per minute with the corresponding filter would be
used.
[0027] Ageing and loss of clarity of the sample tube 110 is likely to occur in most applications
of the device and thus some compensation or correction scheme may be implemented for
continued proper measurements to be taken. One such scheme would be to periodically
allow known clean liquid to be measured by the device and note the turbidity value
which will be greater than when the sample tube was new. This measured value represents
the loss in light transmisitivity of the sample tube 110, and this value can be subtracted
from any subsequent reading on turbid liquids until the next calibration cycle is
performed and a new offset value is established.
[0028] The ramped implementation should be implemented such that the light intensity range
is large enough to cover the full range of expected turbidity values and the possible
loss of transmisitivity of the sample tube.
[0029] Both of the disclosed embodiments (i.e., stepped intensity and ramped intensity)
will yield useful and valid data. The ramped approach will provide a step-less, non
overlapping range of values and may require fewer components to manufacture. The stepped
approach produces a range of values that may overlap and not be discrete, requiring
more intelligence in the appliance control system to properly interpret the data and
perform the appropriate action.
[0030] The stepped method may be advantageous if both average turbidity and particle data
is desired. Using the stepped method, once the proper intensity step is chosen, the
average turbidity level can be determined and then the light emitter intensity level
could be maintained instead of switching to the next intensity in the sequence. During
this extended time the variations in received signal from the light receiver 116 (e.g.,
due to particle settling) could be processed to provide useful information about the
size and quantity of suspended particles in the liquid sample.
[0031] The stepped light intensity and ramp light intensity approaches allow for soil samples
to undergo a number of complete cycle sweeps within a given time period. Useful information
that characterizes the soil can be gathered during the sweeps, specifically: (1) light
receiver voltage level output (i.e., V(t) - discrete voltage values at points in time
indicate the turbidity level at that specific moment), useful for basic measurement
and useful for setting action thresholds; (2) rate of change in light receiver voltage
level output over time (i.e., dV/dt), which (i) can be calculated within a specific
sample or from sample to sample, (ii) provides information related to the presence
of particles in the solution (e.g., the greater the rate of change indicates the greater
amount of particles that are settling, which information is useful because the presence
of a significant amount of particles will increase the likelihood of soil re-deposition)
and (iii) provides information related to the soil level trends; (3) variance in light
receiver voltage level output (i.e., the variance of the light receiver voltage values
within a given period of time (applies to stepped approach), which (i) can be calculated
over a given light emitter intensity and/or from sample to sample and (ii) provides
information related to the presence of particles in the solution.
[0032] Referring now to Fig. 3, an alternative warewash machine embodiment is shown, which
is of the box-type (also known as batch type or door type machines). The machine 140
includes a housing 142 defining a wash chamber 144 that is accessible by a door 146.
The door may be pivotally mounted (e.g., in the case of an undercounter machine) or
mounted for vertical, sliding movement (e.g., in the case of a hood-type machine).
Wares are manually moved into the chamber 144 for cleaning, and manually removed when
the cleaning cycle has been completed. A sump tank 148 is located below the chamber
144 and a pump 150 and line 152 are provided to deliver water from the sump to nozzles
154 of upper and lower spray arms 156 (e.g., of the rotating type). A detergent supply
158 and associated pump may be provided to deliver detergent to the sump 148 in a
metered manner. Other forms of detergent supply may be used, such as manual placement
of a block/solid type detergent product. A booster heater 162 receives water from
a fresh water supply input 164 via a valve 166 or pump and has an output line 168
that delivers water to the nozzles 154 or, in the alternative, to a set of separate
rinse arms with associated nozzles (not shown). A rinse aid supply 170 and associated
pump 172 is provided to deliver rinse aid to the booster tank 162 in a metered manner.
The sump 148 includes an associated drain outlet 174 that leads to a sensor assembly
108 (shown in dashed line form as a box) which could be similar to that of Fig. 2.
A drain valve 110 is provided to control draining, but a pumped drain line system
could alternatively be provided. A controller 180 is provided to operate the various
valves and pumps in accordance with one or more programmed cleaning cycles.
[0033] Machine actions based on determined turbidity/soil level will generally be determined
by the type and configuration of warewash machine with the goal of reducing the potential
for soil re-deposition. The basic types of machines can be divided into two categories,
the conveyor-type (e.g., per Fig.l) and the box-type (e.g., per Fig. 3).
[0034] In the case of the box-type machine, variables that can be controlled based on the
soil level in the sump tank 148 include, by way of example: (1) frequency and duration
of wash (e.g., by controlling the duration of operation of pump 150), (2) drop down
duration (i.e., the dwell time between the spraying of detergent laden wash liquid
and the subsequent spraying of clean rinse liquid; e.g., by controlling when the booster
water is delivered following cessation of pump 150 operation), (3) frequency and duration
of draining of the sump tank 148 (e.g, via control of valve 110), (4) rinse duration
and/or rinse water volume (e.g., by controlling how long valve 166 is maintained open),
(5) rinse aid dosing (e.g., by controlling operation of pump 172), (6) detergent dosing
(e.g., by controlling operation of pump 160), (7) steam cycle (if available), (8)
drying duration (e.g., by controlling operation of a blower and/or heating element
used during drying), (9) interruption of the wash with a partial drain followed by
refill and continuation of the wash and (10) implementation of a partial or full drain
after wash and repetition of the wash cycle before rinse.
[0035] Referring to Fig. 4, in the case of the box-type machine an exemplary cycle Tc is
delineated by a wash period W (e.g., during which detergent laden liquid is recirculated),
a drop down period DD during which recirculation of wash liquid stops and the machine
dwells to allow liquid to drop down off of the ware and a rinse period R during which
clean rinse liquid is sprayed on the wares. Two exemplary water sample times are shown
at drain times D1 and D2. Sampling at D1 could primarily be used to determine whether
to modify wash duration, drop down duration, timing of drain time D2, volume drained
at drain time D2, rinse duration, rinse aid dosing and detergent dosing. Sampling
a D2 could primarily be used to determine whether to modify drop down duration, introduction
of a third drain time for sampling and its associated volume and rinse duration.
[0036] In the case of the conveyor-type machine variables that can be controlled based on
the soil level in the monitored tank or tanks include, by way of example: (1) dilution
of pre-wash (e.g., by controlling valve 76), (2) dilution of main wash (e.g., by controlling
valve 78), (3) dilution of post wash (e.g., by controlling valve 80), (4) conveyor
speed (e.g., by controlling a motor associated with the conveyor 12), (5) drain valves
or drain pumps associated with the tanks, (6) final rinse flow rate (e.g., by controlling
valve 56 or a pump associated with the rinse line), (7) wash flow rate (e.g., by controlling
operation of pump 36), (8) frequency and duration of tank drains, (9) rinse aid dosing
(e.g., by controlling operation of pump 92) and (10) detergent dosing (e.g., by controlling
operation of pump 98.
[0037] On occasion, it may be desirable to check the integrity of the soil sensor assembly
108. A method is to inject clean water into the sensor may be provided and the sensor
arrangement operated. If the light receiver voltage levels are not within a set tolerance
and/or if the soil sensor assembly operation stops, an error message is given (e.g.,
via the controller 100 to energize a visual or audible annunciator). An error offset
may allow for continued operation.
[0038] Although the invention has been described and illustrated in detail it is to be clearly
understood that the same is intended by way of illustration and example only and is
not intended to be taken by way of limitation. It is recognized that numerous other
variations.
1. A warewash machine (10), comprising:
a tank (26; 34; 42; 148) for holding liquid to be sprayed on items in a spray chamber;
a recirculation line (30; 38; 46; 152) for delivering liquid from the tank to nozzles
(32; 40; 48; 154) for spraying;
a sensor arrangement (108) for monitoring condition of tank liquid, the sensor arrangement
including a light emitter (114) and a light receiver (116) and being located outside
of said tank; and
a control (100; 180) for monitoring output of the light receiver (116),
wherein the sensor arrangement (108) is located along a path that is one
of a drain line (104) of the tank, the drain line (104) being connected to an outlet
(106) of the tank and leading to a facility drain, or a line (122) connected in parallel
with the drain line (104),
characterised in that the control (100) is configured to implement a liquid monitoring operation by means
of said sensor arrangement (108) after liquid travel along the path has stopped and
a settling period has occurred, wherein the settling period is applied prior to triggering
the sensor arrangement (108) for monitoring.
2. The machine of claim 1, wherein:
the machine is a box-type machine and the monitoring occurs (1) during a recirculating
washing operation and/or (2) during a drop down period following the recirculating
washing operation.
3. The machine of one of claims 1 to 2 wherein:
the machine is a box-type machine and the control is configured to effect one or more
of the following operations based upon output from the sensor arrangement (i) frequency
and/or duration of the recirculating washing operation of a cleaning cycle, (ii) drop
down duration, (iii) frequency and/or duration of sump drainage, (iv) rinse duration
and/or rinse water volume, (v) rinse aid dosing level, (vi) detergent dosing level,
(vii) steam cycle, (viii) drying duration, (ix) interruption of the recirculating
washing operation of a cleaning cycle with a partial drain followed by refill and
continuation of the recirculating washing operation and/or (x) implementation of a
partial or full drain after the recirculating washing operation of a cleaning cycle
and repetition of the recirculating washing operation of the cleaning cycle before
rinse.
4. The machine of claim 1,
wherein:
the machine is a conveyor-type machine and the tank (26; 34; 42) is associated with
one of a pre-wash zone (16), wash zone (18) or post-wash zone (20) of the machine.
5. The machine of claim 4, wherein:
the control (100) is configured to effect one or more of the following operations
based upon output from the sensor arrangement (i) dilution of pre-wash liquid, (ii)
dilution of main wash liquid, (iii) dilution of post-wash liquid, (iv) conveyance
speed, (v) partial or full tank drainage, (vi) final rinse flow rate, (vii) wash flow
rate, (viii) rinse aid dosing and/or (ix) detergent dosing.
6. The machine of one of the preceding claims, wherein:
the control (100; 180) evaluates one or more of (1) discrete output level of the light
receiver (116) at one or more points in time, (2) a rate of change in output level
of the light receiver with respect to time and/or (3) a variance in output level of
the light receiver within a set period of time.
7. The machine of one of the preceding claims, wherein:
the sensor arrangement (108) includes vertically spaced light emitter-light receiver
pairs at different heights in a sampling zone.
8. The machine of one of the preceding claims, wherein:
the sensor arrangement is formed by a clear tubing structure (110) with a sensor module
(112) mounted thereto, the clear tubing structure forming part of the path.
9. The machine of claim 8, wherein:
the light emitter (114) is located on one side of the clear tubing structure (110)
and the light receiver (116) is located at an opposite side of the clear tubing structure.
10. The machine of one of the preceding claims, wherein:
the control is configured to effect energization of the light emitter so as to produce
a varying light intensity output from the light emitter.
11. The machine of claim 10, wherein:
the control (100; 180) is configured to effect energization of the light emitter so
as to produce (i) a plurality of stepped light intensities or (ii) a ramped light
intensity.
12. A method of detecting soiling of liquid in a tank of a warewash machine, the warewash
machine comprising such a tank (26; 34; 42; 148) for holding liquid to be sprayed
on items in a spray chamber, a recirculation line (30; 38; 46; 152) for delivering
liquid from the tank to nozzles (32; 40; 48; 154) for spraying, a sensor arrangement
(108) located outside of said tank for monitoring condition of tank liquid, the sensor
arrangement including a light emitter (114) and a light receiver (116), a control
(100; 180) for monitoring output of the light receiver (116) by means of said sensor
arrangement, the method comprising the steps of:
locating the sensor arrangement (108) along a path that is one of a drain line (104)
of the tank, the drain line (104) being connected to an outlet (106) of the tank and
leading to a facility drain, or a line (122) connected in parallel with the drain
line (104);
characterised in that the method comprises further:
implementing a liquid monitoring operation using the sensor arrangement (108) after
liquid travel along the path has stopped and a setting period has occurred, wherein
the settling period is applied prior to triggering the sensor arrangement (108) for
monitoring.
13. The method of claim 12 wherein during the liquid monitoring operation the control
evaluates one or more of (1) discrete output level of the light receiver at one or
more points in time, (2) a rate of change in output level of the light receiver with
respect to time and/or (3) a variance in output level of the light receiver within
a set period of time.
1. Geschirrspülmaschine (10), die Folgendes umfasst:
einen Tank (26; 34; 42; 148) für Flüssigkeiten, die auf Gegenstände in einer Sprühkammer
gesprüht werden;
eine Rückführungsleitung (30; 38; 46; 152), um Flüssigkeit von dem Tank zu Düsen (32;
40; 48; 154) zum Sprühen zu befördern;
eine Sensoranordnung (108) zum Überwachen des Zustands der Tankflüssigkeit, wobei
die Sensoranordnung einen Lichtemitter (114) und einen Lichtempfänger (116) enthält
und außerhalb des Tanks liegt; und
eine Steuerung (100; 180) zum Überwachen der Ausgabe des Lichtempfängers (116), wobei
die Sensoranordnung (108) entlang eines Pfades liegt, der entweder einer Ablaufleitung
(104) des Tanks, wobei die Ablaufleitung (104) mit einem Auslass (106) des Tanks verbunden
ist und zu einem Anlagenablauf führt, oder einer Leitung (122) entspricht, die parallel
mit der Ablaufleitung (104) verbunden ist, dadurch gekennzeichnet, dass die Steuerung (100) konfiguriert ist, einen Flüssigkeitsüberwachungsvorgang durch
die Sensoranordnung (108) zu implementieren, nachdem die Flüssigkeitsbewegung entlang
des Pfades aufgehört hat und eine Absetzzeit aufgetreten ist, wobei die Absetzzeit
vor dem Auslösen der Sensoranordnung (108) zum Überwachen angewendet wird.
2. Maschine nach Anspruch 1, wobei:
die Maschine eine kastenförmige Maschine ist und das Überwachen (1) während eines
Umlaufspülvorgangs und/oder (2) während einer Abtropfzeit, die dem Umlaufspülvorgang
folgt, auftritt.
3. Maschine nach einem der Ansprüche 1 bis 2, wobei:
die Maschine eine kastenförmige Maschine ist und die Steuerung konfiguriert ist, basierend
auf der Ausgabe der Sensoranordnung einen oder mehrere der folgenden Vorgänge zu beeinflussen:
(i) Häufigkeit und/oder Dauer des Umlaufspülvorgangs eines Reinigungszyklus, (ii)
Abtropfdauer, (iii) Häufigkeit und/oder Dauer des Ablaufens des Sammelbehälters, (iv)
Spüldauer und/oder Spülwassermenge, (v) Klarspülmitteldosierungshöhe, (vi) Reinigungsmitteldosierungshöhe,
(vii) Dampfzyklus, (viii) Trocknungsdauer, (ix) Unterbrechung des Umlaufspülvorgangs
eines Reinigungszyklus mit einem teilweisen Ablauf, gefolgt von Nachfüllung und Fortsetzung
des Umlaufspülvorgangs und/oder (x) Implementierung eines teilweisen oder vollständigen
Ablaufens nach dem Umlaufspülvorgang eines Reinigungszyklus und Wiederholung des Umlaufspülvorgangs
des Reinigungszyklus vor dem Spülen.
4. Maschine nach Anspruch 1, wobei die Maschine einer Bandspülmaschine entspricht und
der Tank (26; 34; 42) einem Vorspül-Bereich (16), einem Spülbereich (18) oder einem
Nachspül-Bereich (20) der Maschine zugeordnet ist.
5. Maschine nach Anspruch 4, wobei:
die Steuerung (100) konfiguriert ist, basierend auf der Ausgabe von der Sensoranordnung
einen oder mehrere der folgenden Vorgänge zu beeinflussen: (i) Verdünnung der Vorspülflüssigkeit,
(ii) Verdünnung der Hauptspülflüssigkeit, (iii) Verdünnung der Nachspülflüssigkeit,
(iv) Transportgeschwindigkeit, (v) teilweiser oder vollständiger Tankablauf, (vi)
Endspül-Durchflussmenge, (vii) Spüldurchflussmenge, (viii) Klarspülmitteldosierung
und/oder (ix) Reinigungsmitteldosierung.
6. Maschine nach einem der vorhergehenden Ansprüche, wobei:
die Steuerung (100; 180) (1) diskrete Ausgabeniveaus der Lichtempfänger (116) zu einem
oder mehreren Zeitpunkten, (2) eine Änderungsrate des Ausgabeniveaus des Lichtempfängers
bezüglich der Zeit und/oder (3) eine Schwankung des Ausgabeniveaus des Lichtempfängers
innerhalb einer eingestellten Zeitspanne auswertet.
7. Maschine nach einem der vorhergehenden Ansprüche, wobei:
die Sensoranordnung (108) in einem Messbereich in unterschiedlichen Höhen vertikal
voneinander beabstandete Lichtemitter-Lichtempfänger-Paare enthält.
8. Maschine nach einem der vorhergehenden Ansprüche, wobei:
die Sensoranordnung durch eine durchsichtige Rohrstruktur (110) mit einem daran montierten
Sensormodul (112) gebildet ist, wobei die durchsichtige Rohrstruktur einen Teil des
Pfades bildet.
9. Maschine nach Anspruch 8, wobei:
der Lichtemitter (114) auf einer Seite der durchsichtigen Rohrstruktur (110) liegt
und der Lichtempfänger (116) auf einer gegenüberliegenden Seite der durchsichtigen
Rohrstruktur liegt.
10. Maschine nach einem der vorhergehenden Ansprüche, wobei:
die Steuerung konfiguriert ist, eine Anregung der Lichtemitter zu beeinflussen, um
eine variierende Lichtintensitätsausgabe von dem Lichtemitter zu erzeugen.
11. Maschine nach Anspruch 10, wobei:
die Steuerung (100; 180) konfiguriert ist, eine Anregung der Lichtemitter zu beeinflussen,
um (i) mehrere stufenförmige Lichtintensitäten oder (ii) eine rampenförmige Lichtintensität
zu erzeugen.
12. Verfahren zum Detektieren von Verschmutzung einer Flüssigkeit in einem Tank einer
Geschirrspülmaschine, wobei die Geschirrspülmaschine Folgendes umfasst: einen derartigen
Tank (26; 34; 42; 148) für Flüssigkeiten, die auf Gegenstände in einer Sprühkammer
gesprüht werden, eine Rückführungsleitung (30; 38; 46; 152), um Flüssigkeit von dem
Tank zu Düsen (32; 40; 48; 154) zum Sprühen zu befördern, eine Sensoranordnung (108),
die außerhalb des Tanks liegt, zum Überwachen des Zustands der Tankflüssigkeit, wobei
die Sensoranordnung einen Lichtemitter (114) und einen Lichtempfänger (116) enthält,
und eine Steuerung (100; 180) zum Überwachen der Ausgabe des Lichtempfängers (116)
durch die Sensoranordnung, wobei das Verfahren die folgenden Schritte umfasst:
Lokalisieren der Sensoranordnung (108), die entlang eines Pfades liegt, der entweder
einer Ablaufleitung (104) des Tanks, wobei die Ablaufleitung (104) mit einem Auslass
(106) des Tanks verbunden ist und zu einem Anlagenablauf führt, oder einer Leitung
(122) entspricht, die parallel mit der Ablaufleitung (104) verbunden ist;
dadurch gekennzeichnet, dass das Verfahren ferner Folgendes umfasst:
Implementieren eines Flüssigkeitsüberwachungsvorgangs unter Verwendung der Sensoranordnung
(108), nachdem die Flüssigkeitsbewegung entlang des Pfades aufgehört hat und eine
Absetzzeit aufgetreten ist, wobei die Absetzzeit vor dem Auslösen der Sensoranordnung
(108) zum Überwachen angewendet wird.
13. Verfahren nach Anspruch 12, wobei während des Flüssigkeitsüberwachungsvorgangs die
Steuerung (1) diskrete Ausgabeniveaus der Lichtempfänger zu einem oder mehreren Zeitpunkten,
(2) eine Änderungsrate des Ausgabeniveaus des Lichtempfängers bezüglich der Zeit und/oder
(3) eine Schwankung des Ausgabeniveaus des Lichtempfängers innerhalb einer eingestellten
Zeitspanne auswertet.
1. Machine à laver la vaisselle (10), comprenant :
un réservoir (26 ; 34 ; 42 ; 148) destiné à contenir un liquide à pulvériser sur des
articles dans une chambre de pulvérisation ;
une conduite de recirculation (30 ; 38 ; 46 ; 152) destinée à distribuer le liquide
du réservoir à des buses (32 ; 40 ; 48 ; 154) pour pulvérisation ;
un agencement de capteur (108) destiné à surveiller l'état du liquide du réservoir,
l'agencement de capteur comportant un émetteur de lumière (114) et un récepteur de
lumière (116) et étant positionné à l'extérieur dudit réservoir ; et
un dispositif de commande (100 ; 180) destiné à surveiller la sortie du récepteur
de lumière (116),
dans laquelle l'agencement de capteur (108) est positionné le long d'un chemin qui
est une conduite de vidange (104) du réservoir, la conduite de vidange (104) étant
raccordée à une sortie (106) du réservoir et conduisant à un écoulement de l'installation,
ou une conduite (122) raccordée parallèlement à la conduite de vidange (104),
caractérisée en ce que le dispositif de commande (100) est configuré pour effectuer une opération de surveillance
du liquide au moyen dudit agencement de capteur (108) après que le déplacement du
liquide le long du chemin s'est arrêté et qu'une période de sédimentation s'est écoulée,
la période de sédimentation étant appliquée avant de déclencher l'agencement de capteur
(108) pour surveillance.
2. Machine de la revendication 1, dans laquelle :
la machine est une machine de type caisson et la surveillance se produit (1) pendant
une opération de lavage avec recirculation et/ou (2) pendant une période de repos
suivant l'opération de lavage avec recirculation.
3. Machine d'une des revendications 1 et 2, dans laquelle :
la machine est une machine de type caisson et le dispositif de commande est configuré
pour effectuer une ou plusieurs des opérations suivantes en fonction de la sortie
de l'agencement de capteur : (i) fréquence et/ou durée de l'opération de lavage avec
recirculation d'un cycle de nettoyage, (ii) durée de repos, (iii) fréquence et/ou
durée de vidange du collecteur, (iv) durée de rinçage et/ou volume d'eau de rinçage,
(v) niveau de dosage d'adjuvant de rinçage, (vi) niveau de dosage de détergent, (vii)
cycle de vapeur, (viii) durée de séchage, (ix) interruption de l'opération de lavage
avec recirculation d'un cycle de nettoyage avec une vidange partielle suivie d'un
remplissage et poursuite de l'opération de lavage avec recirculation, et/ou (x) réalisation
d'une vidange partielle ou totale après l'opération de lavage avec recirculation d'un
cycle de nettoyage et répétition de l'opération de lavage avec recirculation du cycle
de nettoyage avant rinçage.
4. Machine de la revendication 1, dans laquelle :
la machine est une machine de type convoyeur et le réservoir (26 ; 34 ; 42) est associé
à une zone de prélavage (16), une zone de lavage (18) ou une zone de post-lavage (20)
de la machine.
5. Machine de la revendication 4, dans laquelle :
le dispositif de commande (100) est configuré pour effectuer une ou plusieurs des
opérations suivantes en fonction de la sortie de l'agencement de capteur : (i) dilution
du liquide de prélavage, (ii) dilution du liquide de lavage principal, (iii) dilution
du liquide de post-lavage, (iv) vitesse de transport, (v) vidange partielle ou totale
du réservoir, (vi) débit de rinçage final, (vii) débit de lavage, (viii) dosage d'adjuvant
de rinçage, et/ou (ix) dosage de détergent.
6. Machine d'une des revendications précédentes, dans laquelle :
le dispositif de commande (100 ; 180) évalue un ou plusieurs des paramètres suivants
: (1) niveau de sortie discret du récepteur de lumière (116) à un ou plusieurs points
temporels, (2) vitesse de changement du niveau de sortie du récepteur de lumière par
rapport au temps, et/ou (3) variance du niveau de sortie du récepteur de lumière à
l'intérieur d'un laps de temps établi.
7. Machine d'une des revendications précédentes, dans laquelle :
l'agencement de capteur (108) comporte des paires émetteur de lumière-récepteur de
lumière espacées verticalement à différentes hauteurs dans une zone d'échantillonnage.
8. Machine d'une des revendications précédentes, dans laquelle :
l'agencement de capteur est constitué d'une structure de tube transparent (110) avec
un module de détection (112) monté sur celle-ci, la structure de tube transparent
formant une partie du chemin.
9. Machine de la revendication 8, dans laquelle :
l'émetteur de lumière (114) est positionné sur un côté de la structure de tube transparent
(110) et le récepteur de lumière (116) est positionné sur un côté opposé de la structure
de tube transparent.
10. Machine d'une des revendications précédentes, dans laquelle :
le dispositif de commande est configuré pour exciter l'émetteur de lumière de manière
à produire une sortie d'intensité lumineuse variable depuis l'émetteur de lumière.
11. Machine de la revendication 10, dans laquelle :
le dispositif de commande (100 ; 180) est configuré pour exciter l'émetteur de lumière
de manière à produire (i) une pluralité d'intensités lumineuses échelonnées ou (ii)
une intensité lumineuse graduée.
12. Procédé de détection de la souillure d'un liquide dans un réservoir d'une machine
à laver la vaisselle, la machine à laver la vaisselle comprenant un tel réservoir
(26 ; 34 ; 42 ; 148) pour contenir un liquide à pulvériser sur des articles dans une
chambre de pulvérisation, une conduite de recirculation (30 ; 38 ; 46 ; 152) destinée
à distribuer le liquide du réservoir à des buses (32 ; 40 ; 48 ; 154) pour pulvérisation,
un agencement de capteur (108) positionné à l'extérieur dudit réservoir pour surveiller
l'état du liquide du réservoir, l'agencement de capteur comportant un émetteur de
lumière (114) et un récepteur de lumière (116), un dispositif de commande (100 ; 180)
destiné à surveiller la sortie du récepteur de lumière (116) au moyen dudit agencement
de capteur, le procédé comprenant les étapes consistant à :
positionner l'agencement de capteur (108) le long d'un chemin qui est une conduite
de vidange (104) du réservoir, la conduite de vidange (104) étant raccordée à une
sortir (106) du réservoir et conduisant à un écoulement de l'installation, ou une
conduite (122) raccordée parallèlement à la conduite de vidange (104) ;
caractérisé en ce que le procédé comprend en outre :
la réalisation d'une opération de surveillance du liquide à l'aide de l'agencement
de capteur (108) après que le déplacement du liquide le long du chemin s'est arrêté
et qu'une période de sédimentation s'est écoulée, la période de sédimentation étant
appliquée avant de déclencher l'agencement de capteur (108) pour surveillance.
13. Procédé de la revendication 12 dans lequel, pendant l'opération de surveillance du
liquide, le dispositif de commande évalue un ou plusieurs des paramètres suivants
: (1) niveau de sortie discret du récepteur de lumière à un ou plusieurs points temporels,
(2) vitesse de changement du niveau de sortie du récepteur de lumière par rapport
au temps, et/ou (3) variance du niveau de sortie du récepteur de lumière à l'intérieur
d'un laps de temps établi.