U.S. patent application number 12/621200 was filed with the patent office on 2011-05-19 for method for operating a ware washer and ware washer.
This patent application is currently assigned to Premark FEG L.L.C.. Invention is credited to Frank A. Bondarowicz, Harald Disch, Klaus Padtberg, Alan J. Varacins.
Application Number | 20110114132 12/621200 |
Document ID | / |
Family ID | 43920870 |
Filed Date | 2011-05-19 |
United States Patent
Application |
20110114132 |
Kind Code |
A1 |
Padtberg; Klaus ; et
al. |
May 19, 2011 |
METHOD FOR OPERATING A WARE WASHER AND WARE WASHER
Abstract
A ware washer, which is designed as a programmable machine or as
a conveyor ware washer, has at least one pump, at least one line
system connected to the pump, and at least one nozzle system
connected to the line system and having at least one nozzle, a
liquid being supplied at least intermittently to the at least one
nozzle via the line system. A sensor device connected to a control
device is provided for detecting a profile of the volumetric flow
rate of the liquid in the line system and for comparing the
detected flow rate profile with a predetermined flow rate profile.
The control device is designed, in the event of a deviation of the
detected flow rate profile from the predetermined flow rate
profile, automatically either to carry out a regulating action on
the operation of the ware washer as a function of the size and the
time gradient of a difference between the predetermined flow rate
profile and the detected flow rate profile or to issue a fault
warning via an optical and/or acoustic interface or to issue a
fault warning to a remote maintenance station via a remote control
interface.
Inventors: |
Padtberg; Klaus; (Korbach,
DE) ; Bondarowicz; Frank A.; (Park Ridge, IL)
; Varacins; Alan J.; (Burlington, WI) ; Disch;
Harald; (Elzach, DE) |
Assignee: |
Premark FEG L.L.C.
Wilmington
DE
|
Family ID: |
43920870 |
Appl. No.: |
12/621200 |
Filed: |
November 18, 2009 |
Current U.S.
Class: |
134/25.2 ;
134/56D |
Current CPC
Class: |
A47L 15/0078 20130101;
A47L 15/0049 20130101; A47L 15/4219 20130101; A47L 2501/26
20130101; A47L 2501/30 20130101; A47L 15/241 20130101; A47L 15/0063
20130101; A47L 2401/14 20130101 |
Class at
Publication: |
134/25.2 ;
134/56.D |
International
Class: |
A47L 15/24 20060101
A47L015/24 |
Claims
1. A method for operating a ware washer which is designed as a
programmable machine or as a conveyor ware washer having at least
one pump, at least one line system connected to the pump, and at
least one nozzle system connected to the line system and having at
least one nozzle, the method having the following method steps:
during the operation of the ware washer, a liquid is supplied at
least intermittently to the at least one nozzle via the line
system; and the profile of the flow rate of the liquid in the line
system is detected and is compared with a predetermined flow rate
profile, characterized, in that, in the event of a deviation of the
detected flow rate profile from the predetermined flow rate
profile, at least one of the following steps is selected and
executed automatically as a function of the size and the time
gradient of a difference between the predetermined flow rate
profile and the detected flow rate profile: i) regulating action is
carried out on the operation of the ware washer; and/or ii) a fault
warning is issued via an optical and/or acoustic interface of the
ware washer; and/or iii) a warning is issued to a remote
maintenance station via a remote control interface of the ware
washer.
2. The method as claimed in claim 1, wherein the at least one pump
is has a washing pump and the at least one nozzle is a washing
nozzle which is connected to the washing pump via the line system
and to which a washing liquid is supplied during a washing process
via the washing pump being activated, and wherein, during the
washing process, the profile of the volumetric flow rate of the
washing liquid in the line system is detected and compared with the
predetermined flow rate profile.
3. The method as claimed in claim 2, wherein the ware washer has a
final rinse pump and at least one final rinse nozzle which is
connected to the final rinse pump via a final rinse line system and
to which a final rinse liquid is supplied during a final rinse
process by the final rinse pump being activated, and wherein,
during a final rinse process, the profile of the volumetric flow
rate of the final rinse liquid in the final rinse line system is
detected and compared with the a predetermined final rinse flow
rate profile.
4. The method as claimed in claim 2, wherein the ware washer has a
valve and at least one final rinse nozzle which is connected to the
valve via a final rinse line system and to which a final rinse
liquid is supplied during the final rinse process by the valve
being opened, and wherein, during the final rinse process, the
profile of the volumetric flow rate of the final rinse liquid in
the final rinse line system is detected and compared with a
predetermined final rinse flow rate profile.
5. The method as claimed in claim 1, wherein at least one of the
steps i) to iii) is selected and executed automatically only when
the deviation of the detected flow rate profile from the
predetermined flow rate profile overshoots or undershoots a set
threshold value.
6. The method as claimed in claim 1, wherein the profile of the
volumetric flow rate is detected in that the volumetric flow rate
is measured continuously within at least one predetermined time
interval, or in that the volumetric flow rate is measured at
predetermined time points or events within at least one
predetermined time interval, and the measured flow rate values are
interpolated.
7. The method as claimed in claim 6, wherein the time interval has
a set length, and wherein the start of the time interval is fixed
by a time point at which the pump is switched on or activated in
such a way that the liquid is supplied via the line system to the
nozzle system having the at least one nozzle.
8. The method as claimed in claim 7, wherein the profile of the
volumetric flow rate is detected in that the volumetric flow rate
is measured continuously or at predetermined time points or events
in a plurality of time intervals preferably directly contiguous to
one another, the start of the first time interval lying at a time
point preferably immediately after the expiry of a starting time of
the flow rate generated in the line system by the pump being
switched on.
9. The method as claimed in claim 1, wherein, in a case when the
detected flow rate profile lies continuously above the
predetermined flow rate profile and the amount of the difference
between the predetermined flow rate profile and the detected flow
rate profile lies continuously within the range between a first
fixed threshold value and a second fixed threshold value, a minor
leak in the line system or nozzle system is concluded
automatically, and wherein a corresponding fault warning then is
issued via the optical and/or acoustic interface; and/or wherein a
corresponding fault warning then is issued via the remote control
interface.
10. The method as claimed in claim 9, wherein, in a case when the
detected flow rate profile lies continuously above the
predetermined flow rate profile and the amount of the difference
between the predetermined flow rate profile and the detected flow
rate profile is continuously above the second fixed threshold
value, a major leak in the line system or nozzle system is
concluded automatically, and a corresponding fault warning is
issued via the optical and/or acoustic interface.
11. The method as claimed in claim 1, wherein, in a case when the
detected flow rate profile lies continuously below the
predetermined flow rate profile and the amount of the difference
between the predetermined flow rate profile and the detected flow
rate profile is continuously above a fixed threshold value, a
blockage in the line system or nozzle system is concluded
automatically, and a corresponding fault warning is issued via the
optical and/or acoustic interface.
12. The method as claimed in claim 11, wherein the at least one
pump is has a washing pump and the at least one nozzle is a washing
nozzle which is connected to the washing pump via the line system
and to which a washing liquid is supplied during a washing process
by the washing pump being activated, and wherein, during the
washing process, the profile of the volumetric flow rate of the
washing liquid in the line system is detected and compared with the
predetermined flow rate profile.
13. The method as claimed in claim 12, wherein, if the ware washer
is designed as a programmable machine, the running time of the
treatment program is increased, preferably in proportion to the
detected flow rate drop; or wherein, if the ware washer is designed
as a conveyor ware washer, the speed at which the washing items to
be treated are transported through the ware washer is reduced
preferably in proportion to the detected flow rate drop.
14. The method as claimed in claim 1, wherein, in a case when,
within a time interval during which the flow rate profile is
detected, the measured volumetric flow rate increases continuously
from a time point and overshoots a predetermined threshold value,
the pump capacity of the pump is automatically adjusted down,
preferably in inverse proportion to a detected flow rate rise.
15. The method as claimed in one of claim 1, wherein, in a case
when, within a time interval during which the flow rate profile is
detected, the measured volumetric flow rate decreases continuously
from a time point and undershoots a predetermined threshold value,
a blockage occurring only during the continuous operation of the
ware washer is concluded automatically, and a corresponding fault
warning is issued via the optical and/or acoustic interface.
16. A ware washer, in particular commercial dishwasher or utensil
ware washer, which is designed as a programmable machine or as a
conveyor ware washer and has the following: at least one pump; at
least one line system connected to the pump; at least one nozzle
system connected to the line system and having at least one nozzle,
a liquid being supplied at least intermittently to the at least one
nozzle via the line system; and a sensor device connected to a
control device, for detecting a profile of the volumetric flow rate
of the liquid in the line system and for comparing the detected
flow rate profile with a predetermined flow rate profile,
characterized, in that the control device is designed, in the event
of a deviation of the detected flow rate profile from the
predetermined flow rate profile, automatically either to carry out
a regulating action on the operation of the ware washer as a
function of the size and the time gradient of a difference between
the predetermined flow rate profile and the detected flow rate
profile or to issue a fault warning via an optical and/or acoustic
interface or to issue a fault warning to a remote maintenance
station via a remote control interface.
17. The ware washer as claimed in claim 16, wherein the ware washer
has, furthermore, the following: at least one valve; at least one
final rinse line system connected to the valve; and at least one
nozzle system connected to the line system and having at least one
final rinse nozzle, wherein the control device is designed,
furthermore, for activating the valve in such a way that a liquid
is supplied at least intermittently to the at least one final rinse
nozzle via the final rinse line system, and wherein the sensor
device is designed, furthermore, for detecting a profile of the
volumetric flow rate of the liquid in the final rinse line system
and for comparing the detected flow rate profile with a
predetermined final rinse flow rate profile.
18. The ware washer as claimed in claim 16, wherein the control
device is designed, furthermore, to carry out a regulating action
on the operation of the ware washer or to issue a fault warning
only when the deviation of the detected flow rate profile from the
predetermined flow rate profile overshoots or undershoots a set
threshold value.
19. The ware washer as claimed in claim 16, wherein the sensor
device has at least one flow sensor, and is designed to detect the
profile of the volumetric flow rate in that the volumetric flow
rate is measured continuously or at predetermined time points or
events by means of the at least one flow sensor within a
predetermined time interval, and, if appropriate, the measured flow
rate values are interpolated.
20. The ware washer as claimed in claim 16, wherein the at least
one pump is ware washer has a washing pump and the at least one
nozzle is a washing nozzle which is connected to the washing pump
via the line system and to which a washing liquid is supplied
during a washing process by the washing pump being activated, and
wherein the sensor device connected to the control device is
designed for detecting the profile of the volumetric flow rate of
the washing liquid in the line system and for comparing the
detected flow rate profile with the predetermined flow rate
profile.
21. The ware washer as claimed in claim 16, wherein the at least
one pump is ware washer has a final rinse pump and the at least one
nozzle is a final rinse nozzle which is connected to the final
rinse pump via the line system and to which a final rinse liquid is
supplied during a final rinse process by the final rinse pump being
activated, and wherein the sensor device connected to the control
device is designed for detecting the profile of the volumetric flow
rate of the final rinse liquid in the line system and for comparing
the detected flow rate profile with the predetermined flow rate
profile.
Description
TECHNICAL FIELD
[0001] The invention relates to a method for operating a ware
washer and to a ware washer, in particular commercial dishwasher or
utensil ware washer, which is designed as a programmable machine or
as a conveyor ware washer.
[0002] The invention is aimed particularly at a method for
operating a ware washer which is designed as a programmable machine
or as a conveyor ware washer and which has at least one pump, a
line system connected to the pump and at least one nozzle connected
to the line system, wherein a liquid is supplied at least
intermittently to the at least one nozzle via the line system while
the ware washer is in operation.
[0003] Furthermore, the invention relates to a ware washer which is
designed as a programmable machine or as a conveyor ware washer and
which has at least one pump, a line system connected to the pump
and at least one nozzle connected to the line system, wherein
liquid is supplied at least intermittently to the at least one
nozzle via the line system.
BACKGROUND
[0004] Programmable machines are manually loadable and unloadable
ware washers. The programmable machines (called "box-type ware
washers" or else "batch dish washers") may be rack-type
push-through ware washers, also called hood ware washers
("hood-type ware washers"), or front loaders ("front loader ware
washers"). Front loaders may be built-under machines ("under
counter machines"), table top machines ("top counter machines") or
free-standing ware washers with front loading ("free standing front
loaders").
[0005] A ware washer designed as a programmable machine usually has
a treatment chamber for the cleaning of wash ware. As a rule,
beneath the treatment chamber, a washing tank is arranged, in which
liquid can flow out of the treatment chamber as a result of
gravity. Located in the washing tank is washing liquid which is
usually water, to which, if appropriate, detergent can be
supplied.
[0006] Furthermore, a ware washer designed as a programmable
machine has a washing system with a washing pump and with a line
system connected to the washing pump and having washing nozzles.
The washing liquid located in the washing tank can be conveyed from
the washing pump to the washing nozzles via the line system and
sprayed through the washing nozzles in the treatment chamber onto
the wash ware to be cleaned. The sprayed washing liquid
subsequently flows back into the washing tank.
[0007] Conveyor ware washers are, in particular, belt-type conveyor
ware washers ("flight-type ware washers") or rack-type conveyor
ware washers ("rack conveyor ware washer"). Conveyor ware washers
are usually employed in the commercial sector.
[0008] In contrast to programmable machines in which the wash ware
to be cleaned remains at a fixed location in the machine during
cleaning, in conveyor ware washers a transport of the wash ware
through various treatment zones of the conveyor ware washer takes
place.
[0009] A conveyor ware washer usually has at least one prewashing
zone and at least one main washing zone which is arranged
downstream of the prewashing zone or prewashing zones, as seen in
the direction of transport of the wash ware. As a rule, at least
one postwashing zone and at least one final rinse zone following
the postwashing zone or postwashing zones are arranged downstream
of the main washing zone or main washing zones, as seen in the
direction of transport. As seen in the direction of transport,
either the wash ware received directly on the conveyor belt or the
wash ware held by racks usually runs in the direction of transport
through an entry tunnel, the following prewashing zone or
prewashing zones, main washing zone or main washing zones,
postwashing zone or postwashing zones, final rinse zone or final
rinse zones and a drying zone into an exit section.
[0010] Said washing zones of the conveyor ware washer are assigned
in each case a washing system which has a washing pump and a line
system (washing line system) which is connected to the washing pump
and via which liquid is supplied to the spray nozzles of the
washing zone. The washing liquid supplied to the spray nozzles is
sprayed in the respective washing zone onto the wash ware which is
transported by a transport device of the conveyor ware washer
through the respective washing zones. Each washing zone is assigned
a tank in which sprayed liquid is received and/or in which liquid
for the spray nozzles of the respective zones is provided.
[0011] In the conveyor ware washers conventionally known from the
prior art, final rinse liquid in the form of fresh water, which may
be pure or mixed with further additives, such as, for example,
rinsing agent, is sprayed onto the wash ware via the spray nozzles
of the final rinse zone. At least part of the sprayed final rinse
liquid is transported from zone to zone, opposite to the direction
of transport of the wash ware, via a cascade system.
[0012] The sprayed final rinse liquid is captured in a tank
(postwashing tank) of the postwashing zone, from which tank it is
conveyed, via the washing pump of the washing system belonging to
the postwashing zone, to the spray nozzles (postwashing nozzles) of
the postwashing zone. Washing liquid is rinsed off from the wash
ware in the postwashing zone. The liquid which in this case occurs
flows into the washing tank of the at least one main washing zone
which precedes the postwashing zone, as seen in the direction of
transport of the wash ware. Here, the liquid is usually provided
with a detergent and sprayed onto the wash ware via the nozzles
(washing nozzles) of the main washing zone by means of a pump
system (washing pump) belonging to the washing system of the main
washing zone. In so far as no further main washing zone is
provided, the liquid subsequently flows from the washing tank of
the main washing zone into the prewashing tank of the prewashing
zone. The liquid in the prewashing tank is sprayed onto the wash
ware via the prewashing nozzles of the prewashing zone by means of
a pump system belonging to the washing system of the prewashing
zone, in order to remove coarse impurities from the wash ware.
[0013] Conventionally, ware washers are equipped with rinsing pumps
which supply the line system of the final rinse zone with the final
rinse liquid to be sprayed. This ensures, in particular, a
virtually constant volume flow of the final rinse liquid in the
final rinse zone. It is also conceivable, however, to utilize the
on-site line pressure, for example the pressure of the fresh water
supply, in order to deliver the final rinse liquid to the line
system of the final rinse zone. In this last-mentioned instance, an
activatable valve may be provided between the line system and the
spray nozzles of the final rinse zone, so that a temporary or
complete interruption in the supply of final rinse liquid to the
spray nozzles can be achieved.
[0014] Irrespective of whether the ware washer is designed as a
programmable machine or as a conveyor ware washer, commercial ware
washers therefore usually comprise at least one pump and/or a valve
which ensure/ensures a virtually constant volume flow of the
washing liquid or final rinse liquid for the duration of a washing
or final rinse process in the treatment chamber (in the case of
programmable machines) or in the respective treatment zone (in the
case of conveyor ware washers). The respective pumps and/or valves
on the line system are switched on and off by means of a control
device (machine control) belonging to the ware washer.
[0015] However, various operating states of the ware washer,
operating errors, insufficient cleaning of the systems or an
incorrect installation of washing or final rinse arms (for example,
after the cleaning of these) may lead to a deviation in the defined
water circulation capacity (flow rate) or to a deviation in the
desired washing pressure or desired rinsing pressure or desired
nozzle pressure and, consequently, to a change in the washing
performance.
[0016] The desired washing pressure of commercial ware washers lies
in a range of approximately 0.1 to 0.8 bar, depending on the type
of machine and its size. The desired final rinse pressure of
commercial ware washers is likewise dependent on the type and size
of the machine, but usually lies in a range of 0.2 to 0.8 bar. The
washing liquid volume flow in commercial built-under machines is
approximately 100 to 200 l/min, and in belt-type conveyor ware
washers is approximately 400 to 800 l/min. The circulated washing
liquid volume flows of hood-type and rack-type conveyor ware
washers are between these. In what are known as commercial "Batch
Type Dishwasher" machines or programmable machines, a final rinse
water quantity of approximately 1.5 to 3.5 l per cycle is consumed.
In continuous final rinse processes, as, for example, in conveyor
ware washers, the volume flow of the final rinse liquid is
approximately 2 to 8 l/min.
[0017] The publication EP 1 278 449 B1 relates to a domestic ware
washer which has a washing system with an intermittently activated
circulation pump and with two rotating spray arms. Furthermore, to
detect a fluid pressure prevailing at the pump inlet, a sensor
device is provided which is connected to a control device of the
ware washer and optionally to an indicator. By the fluid pressure
prevailing at the pump inlet being detected, it can be ascertained
whether the spray arms of the ware washer are functioning properly.
In particular, it can be ascertained whether the free rotatability
of the spray arms is blocked, on account of pieces of crockery in
the treatment chamber. If such an instance occurs, the intermittent
operation of the circulation pump is changed correspondingly so
that a predetermined washing result can be achieved.
[0018] The publication WO 2004/096006 A2 relates to a ware washer
with a washing liquid circuit which is provided with a pressure
sensor. It is possible via the pressure sensor to detect whether
the hydrostatic pressure of the washing liquid circulating in the
washing liquid circuit undershoots a prefixed threshold value. This
occurs, for example, when a filter provided in the washing liquid
circuit becomes clogged. In such an instance, there is the risk
that the wash ware to be cleaned is not treated sufficiently. In
order to counteract this, it is proposed to equip the ware washer
with an additional washing liquid circuit which is cut in, as
required, so that the washing liquid can ultimately be sprayed onto
the wash ware with a predetermined desired nozzle pressure.
[0019] A method for operating a circulation pump in a
program-controlled ware washer is known from the publication DE 197
50 266 A1. The circulation pump is activated intermittently so that
pressure fluctuations can be introduced into the washing liquid in
a directed manner. This is intended to promote the water flow at a
screen, provided in a washing liquid circuit, with the effect of
screen cleaning and dirt discharge. In order to prevent the
situation where the deliberately introduced instability in the
pressure profile is reduced on account of a loading of the washing
liquid with foam or on account of the degree of contamination of
the washing liquid, there is provision for, with the aid of a
pressure sensor, detecting the pressure profile in the circulated
washing liquid and, in particular, the absence of pressure
fluctuations or of specific measurable pressure peaks. If such an
instance occurs, instability is caused in the pressure profile due
to an abrupt reduction in the pump rotational speed.
[0020] The publication EP 1 008 324 A1 relates to a method for the
cleaning of wash ware in a ware washer, in which washing liquid in
a washing liquid circuit is sprayed onto a wash ware to be cleaned.
In the washing liquid circuit, a pressure sensor is provided, via
which the pressure profile of the pump pressure is detected. By
means of the detected pressure profile, it is determined whether
air is unintentionally sucked in by means of the circulation pump
and is therefore in an unstable hydraulic state. In such an
instance, the circulation pump of the ware washer is temporarily
switched off or throttled.
SUMMARY
[0021] The set problem on which the present invention is based is
to ascertain potential deviations in the water circulation capacity
or potential deviations in the flow rate and automatically react
correspondingly, in order to counteract the deviation in the water
circulation capacity.
[0022] In particular, the invention is to achieve the object of
providing a ware washer designed as a programmable machine or a
conveyor ware washer which has a washing system with a washing
pump, with a line system connected to the washing pump and with
washing nozzles, potential malfunctions of the ware washer which
have or may have an adverse influence on the treatment result being
ascertained as early as possible. After potential malfunctions have
been ascertained, countermeasures are to be automatically
initiated, by means of which a deviation in the defined water
circulation capacity or a change in the washing performance can be
compensated as early as possible.
[0023] Furthermore, the object of specifying a corresponding method
for operating such a ware washer is to be achieved.
[0024] The solution according to the invention is distinguished in
that potential deviations in the volumetric flow rate are detected,
using suitable flow sensors, and deviations are communicated via
fault warnings to the customer or to the ware washer operator or
via a remote control interface to the manufacturing company or to
the competent remote maintenance system or are counteracted by
means of a change of process parameters.
[0025] A suitable flow sensor is a device for sensing the rate of
fluid flow. Typically a flow sensor is the sensing element used in
a flow meter, or flow logger, to record the flow rate of fluids. As
is true for all sensors, absolute accuracy of a measurement
requires a functionality for calibration. There are various kinds
of flow sensors and flow meters, including some that have a vane
that is pushed by the fluid, and can drive a rotary potentiometer,
or similar device.
[0026] In this case, the invention is based on the recognition
that, in a situation where the desired flow rate in the line system
is overshot immediately after a pump is switched on, this points to
a leak in the line system. By contrast, a high overshooting of the
desired flow rate is an indication of a faulty installation of the
washing or final rinse arms. If the flow rate lies below the
desired flow rate, this is an indicator of blockages in the lines
or nozzles.
[0027] In particular, according to the invention, there is
provision, with the aid of a flow sensor, for detecting the profile
of the flow rate of the liquid in the line system and comparing it
with a predetermined flow rate profile (the ideal desired flow rate
profile, in the fault-free operation of the machine). If there is a
deviation in the detected flow rate profile from the predetermined
ideal flow rate profile, at least one of the following steps is
selected and executed automatically as a function of the type of
deviation: [0028] i) a regulating action is carried out on the
operation of the ware washer; and/or [0029] ii) a fault warning is
issued via an optical and/or acoustic interface of the ware washer;
and/or [0030] iii) a warning is issued to a remote maintenance
station via a remote control interface of the ware washer.
[0031] The type of deviation of the detected flow rate profile from
the predetermined (ideal) flow rate profile is determined, in
particular, by the answers to the following questions: [0032] i)
does the detected flow rate profile lie below or above the ideal
flow rate profile? [0033] ii) does the deviation in the detected
flow rate profile from the predetermined (ideal) flow rate profile
decrease over time or does it remain constant? [0034] iii) does the
deviation occur only during continuous operation or is a deviation
present even at the commencement of the operation of the ware
washer?
[0035] In the solution according to the invention, therefore, first
the type of deviation of the detected flow rate profile from the
predetermined (ideal) flow rate profile is determined. Thus, a
conclusion as to the cause of the deviation of the detected flow
rate profile from the predetermined (ideal) flow rate profile and
therefore a conclusion as to the cause of the deviation can be
drawn. It is subsequently established whether the deviation,
detected via the flow rate profile, may lead to a change in the
washing or final rinse performance of the ware washer. Should this
be the case, a check is made as to whether there is a possibility
of carrying out a regulating action on the operation of the ware
washer, so that the potential change in the washing or final rinse
performance can be compensated.
[0036] Simultaneously with or alternatively to this, as a function
of the determined cause of the deviation from the defined water
circulation capacity and from in the defined desired flow rate
respectively, an optical and/or acoustic fault warning is issued to
the machine operator, so that the latter can undertake
corresponding measures. This is the case particularly when an
operating error is the cause of the deviation from the defined
water circulation capacity.
[0037] If, by contrast, it is determined that the assistance of
external servicing personnel is required in order to eliminate the
fault, a corresponding fault warning is issued to a remote
maintenance station automatically by the system via a remote
control interface of the ware washer. This may be the case, for
example, when an insufficient cleaning or final rinse performance
of the washing or final rinse system or an incorrect installation
of the washing or final rinse arms or a leak in the line system is
the cause of the deviation from the defined water circulation
capacity and from the defined desired pressure, respectively.
[0038] The remote maintenance of ware washers is gaining increasing
importance in the support of the hardware and software of ware
washers. Due to the ever greater interlinking of the control
devices of ware washers via the Internet, to the set-up of in-house
intranets and to conventional telecommunication pathways (ISDN,
telephone), the possibilities of direct support assistance are
extended. Not least because of the possibilities for making savings
in travel costs and better resource utilization (personnel and
technology), remote maintenance products are used in order to lower
costs in businesses. Remote maintenance programs enable the
servicing engineer sitting at a distance to have direct access to
the control device of the ware washer to be maintained and to carry
out corresponding actions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] The invention is described in more detail below with
reference to the drawings in which:
[0040] FIG. 1 shows diagrammatically a ware washer, designed in the
form of a programmable machine, according to a preferred embodiment
of the invention;
[0041] FIG. 2 shows diagrammatically a conveyor ware washer
according to a further preferred embodiment of the invention;
[0042] FIG. 3 shows diagrammatically the set-up of a washing system
for a conveyor ware washer according to the invention or a ware
washer according to the invention designed as a programmable
machine;
[0043] FIG. 4a to f show diagrammatic flow rate profiles to explain
the principle of the detection of disturbing influences with the
aid of the flow rate prevailing in the washing system; and
[0044] FIG. 5a to f show diagrammatic flow rate profiles to explain
the principle of the detection of disturbing influences with the
aid of the flow rate prevailing in the final rinse system.
DETAILED DESCRIPTION
[0045] FIG. 1 shows a diagrammatic longitudinal sectional view of
an example of a conveyor ware washer 50. The conveyor ware washer
50 according to the illustration in FIG. 1 has a prewashing zone 51
and a main washing zone 52 which is arranged downstream of the
prewashing zone 51, as seen in the direction of transport T of the
wash ware (not illustrated in FIG. 1). In the conveyor ware washer
50 illustrated in FIG. 1, a postwashing zone 53 and a final rinse
zone 54 following the postwashing zone 53 are arranged downstream
of the main washing zone 52, as seen in the direction of transport
T. As seen in the direction of transport T, either wash ware
received directly on the conveyor belt 58 or wash ware held by
baskets runs in the direction of transport T through an entry
tunnel 55, through the following prewashing zone 51, the main
washing zone 52, the postwashing zone 53, the final rinse zone 54
and through a drying zone 56 into an exit section 57.
[0046] Said treatment zones 51, 52, 53, 54 of the conveyor ware
washer 50 are assigned in each case spray nozzles 13-1, 13-2, 13-3,
13-4, via which liquid is sprayed onto the wash ware which is
transported by the conveyor belt 58 through the respective
treatment zones 51, 52, 53, 54. At least each washing zone
(prewashing zone 51, main washing zone 52, postwashing zone 53) is
assigned a tank (washing tank 14-1, 14-2, 14-3), in which sprayed
liquid is received and/or in which liquid for the spray nozzles
13-1, 13-2, 13-3 of the respective zones 51, 52, 53 is
provided.
[0047] The prewashing zone 51, the main washing zone 52 and the
postwashing zone 53 of the conveyor ware washer 50 according to the
embodiment illustrated in FIG. 1 have in each case a washing system
10-1, 10-2, 10-3. Each washing system 10-1, 10-2, 10-3 is composed
of a washing pump 11-1, 11-2, 11-3, and a line system 12-1, 12-2,
12-3 connected to the washing pump 11-1, 11-2, 11-3 and of the
spray nozzles 13-1, 13-2, 13-3 connected to the line system 12-1,
12-2, 12-3.
[0048] Further, a control device 20 is provided which serves (inter
alia) for suitably activating the respective washing pumps 11-1,
11-2, 11-3 of the washing systems 10-1, 10-2, 10-3 during a washing
process, in order at least intermittently to supply liquid via the
associated line system 12-1, 12-2, 12-3 to the spray nozzles 13-1,
13-2, 13-3 of the nozzle system belonging to the respective washing
system 10-1, 10-2, 10-3.
[0049] In particular, in the conveyor ware washer 50 illustrated in
FIG. 1, final rinse liquid in the form of fresh water, which may be
mixed with further additives, such as, for example, rinsing agent,
is sprayed onto the wash ware, not illustrated in FIG. 1, via the
spray nozzles 13-4 of the final rinse zone 54 which are arranged
above and below the conveyor belt 58. As illustrated in FIG. 1,
laterally arranged spray nozzles 13-5 may also be provided in the
final rinse zone 54.
[0050] Part of the sprayed final rinse liquid is transported from
zone to zone, opposite the direction of transport T of the wash
ware, via a cascade system. The remaining part is conducted
directly into the prewashing tank 14-1 via a valve 59 and a bypass
line 100.
[0051] The sprayed final rinse liquid is captured in the tank
(postwashing tank 14-3) of the postwashing zone 53, from which tank
it is conveyed to the spray nozzles 13-3 (postwashing nozzles) of
the postwashing zone 53 via the washing pump 11-3 belonging to the
washing system 10-3 of the postwashing zone 53. Washing liquid is
rinsed off from the wash ware in the postwashing zone 53. The
liquid which in this case occurs flows into the washing tank 14-2
of the main washing zone 52, is usually provided with a detergent
and is sprayed onto the wash ware, with the aid of a washing pump
11-2 belonging to the washing system 10-2 of the main washing zone
52, via the spray nozzles 13-2 (washing nozzles) of the washing
system 10-2 belonging to the main washing zone 52.
[0052] The liquid subsequently flows from the washing tank 14-2 of
the main washing zone 52 into the prewashing tank 14-1 of the
prewashing zone 51. The liquid in the prewashing tank 14-1 is
sprayed onto the wash ware, by means of a washing pump 11-1
belonging to the washing system 10-1 of the prewashing zone 51, via
the spray nozzles 13-1 (prewashing nozzles) of the washing system
10-1 belonging to the prewashing zone 51, in order to move coarse
impurities from the wash ware.
[0053] Each washing system 10-1, 10-2, 10-3 of the conveyor ware
washer 50 according to FIG. 1 has a sensor device 30 connected to
the control device 20. The sensor devices 30 serve for detecting a
profile of the flow rate of the liquid (washing liquid) which is
conveyed to the corresponding spray nozzles 13-1, 13-2, 13-3 in the
respective line system 12-1, 12-2, 12-3 of the associated washing
system 10-1, 10-2, 10-3 with the aid of the associated washing pump
11-1, 11-2, 11-3. The detected flow rate profile is subsequently
compared with a predetermined desired flow rate profile which is
filed in a storage device 21 belonging to the control device
20.
[0054] In the conveyor ware washer 50 illustrated in FIG. 1, the
control device 20 is designed, in the event of a deviation of the
detected flow rate profile from the predetermined flow rate profile
either automatically to carry out, as a function of the size and
time gradient of a difference between the predetermined flow rate
profile and the detected flow rate profile, a regulating action on
the washing process proceeding in the respective treatment zone 51,
52, 53, or to issue a fault warning via an optical and/or acoustic
interface 22 or to issue a fault warning to a remote maintenance
station via a remote control interface 23. How this takes place in
particular is stated later with reference to the graphs according
to FIGS. 4a to 4f.
[0055] FIG. 2 illustrates a diagrammatic longitudinal sectional
view of a ware washer 40 designed in the form of a programmable
machine. The ware washer 40 designed as a programmable machine has
a treatment chamber 41 for the cleaning and final rinse of wash
ware, not illustrated in FIG. 2. Beneath the treatment chamber 41,
a tank 14-4 is arranged, in which liquid can flow back out of the
treatment chamber 41 as a result of gravity. The tank 14-4 may be
covered at the transition to the treatment chamber 41 with the aid
of a screen, not illustrated in FIG. 2.
[0056] In the tank 14-4, liquid is located, which is usually water,
to which, if appropriate, detergent or rinsing agent can be
supplied automatically in a controlled way by a detergent or
rinsing agent metering device, not illustrated in FIG. 2. The
liquid can be conveyed via a line system 12-5 to washing nozzles
13-7 by a washing pump 11-5 belonging to a washing system 10-4 of
the ware washer 40 and can be sprayed through these washing nozzles
13-7 in the treatment chamber 41 onto the wash ware to be cleaned.
The sprayed liquid subsequently flows back into the tank 14-4. A
discharge line 42 with a drain pump 43 may be connected to the
lower end of the tank 14-4, in order to empty the tank 14-4, as
required.
[0057] Like the conveyor ware washer 50 illustrated in FIG. 1, the
ware washer 40 according to FIG. 2, designed as a programmable
machine, has, furthermore, a control device 20. This control device
20 serves (inter alia) for suitably activating the washing pump
11-5 of the washing system 10-4 while the ware washer is in
operation, in order at least temporarily to supply liquid to the
washing nozzles 13-7 via the line system 12-5.
[0058] Furthermore, the washing system 10-4 of the ware washer 40
according to FIG. 2, designed as a programmable machine, has a
sensor device 30 connected to the control device 20. As in the
conveyor ware washer 50 according to the illustration in FIG. 1,
the sensor device 30 serves for detecting a profile of the
hydrostatic flow rate of the liquid (washing liquid) which is
conveyed to the washing nozzles 13-7 in the line system 12-5 of the
washing system 10-4 with the aid of the washing pump 11-5.
Likewise, in the embodiment according to FIG. 2, the detected flow
rate profile is subsequently compared with a predetermined desired
flow rate profile which is filed in the storage device 21 belonging
to the control device 20.
[0059] In functional terms, the control device 20 provided in the
ware washer 40 according to FIG. 2, designed as a programmable
machine, is identical to the control device which is used in the
conveyor ware washer 50 according to FIG. 1. For this reason, there
is no need at this juncture for a detailed description of the
functioning of the control device 20. Instead, reference is made in
this regard to the following statements relating to FIGS. 3 and
4.
[0060] It remains to be stated that both the ware washer 40
according to FIG. 2, designed as a programmable machine, and the
conveyor ware washer 50 according to FIG. 1 in each case have at
least one washing system, also designated below simply as the
"washing system 10", which comprises an associated washing pump
(also designated below simply as the "washing pump 11"), an
associated line system (also designated below simply as the "line
system 12") connected to the washing pump 11, and also associated
washing nozzles (also designated below simply as the "washing
nozzles 13") connected to the line system 12 and integrated in
washing arms 15-1 and 15-2. In the ware washer 40 according to FIG.
2, designed as a programmable machine, the washing system 10-4 is
based on the washing pump 11-5, the washing line system 12-5 and
the washing nozzles 13-7. In the conveyor ware washer 50 according
to FIG. 1, at least the prewashing zone 51, the main washing zone
52 and the postwashing zone 53 are provided in each case with a
corresponding washing system 10-1, 10-2, 10-3. These washing
systems 10-1, 10-2, 10-3 have in each case a washing pump 11-1,
11-2, 11-3, a line system 12-1, 12-2, 12-3 connected to the washing
pump 11-1, 11-2, 11-3, and spray nozzles 13-1, 13-2, 13-3 connected
to the line system 12-1, 12-2, 12-3 and designated below as
"washing nozzles 13".
[0061] FIG. 3 illustrates a detailed and diagrammatic view of a
preferred embodiment of a washing system 10 which may be used, for
example, in the conveyor ware washer 50 illustrated in FIG. 1 or in
the ware washer 40 illustrated in FIG. 2 and designed as a
programmable machine.
[0062] In the washing system 10 according to FIG. 3, liquid
(washing liquid) is routed in a circuit by a washing pump 11 from a
tank 14 via a line system 12 to washing nozzles 13 which are
installed in upper and lower washing arms 15-1, 15-2. In a ware
washer (for example, according to FIG. 2) designed as a
programmable machine, the washing arms 15-1, 15-2 having the
washing nozzles 13 are arranged in the treatment chamber 41 shown
in FIG. 2, so that the washing liquid can be conveyed out of the
tank 14 via the line system 12 to the washing nozzles 13 by the
washing pump 11 and sprayed through the washing nozzles 13 in the
treatment chamber onto the wash ware to be cleaned (cf. FIG.
2).
[0063] In a conveyor ware washer 50 (for example, according to FIG.
1), the washing system 10 illustrated in FIG. 3 may be provided in
at least one of the respective washing zones (prewashing zone 51,
main washing zone 52, postwashing zone 53). It is, of course, also
conceivable not (only) to use the washing system 10 according to
FIG. 3 in one of the washing zones 51, 52, 53, but also in the
final rinse zone 54 of the conveyor ware washer 50.
[0064] Regardless of the question of in which of the respective
treatment zones of a conveyor ware washer the washing system 10
according to the illustration in FIG. 3 is used, in the conveyor
ware washer, and also in the ware washer designed as a programmable
machine, the washing liquid is sprayed through the washing tank 14
onto the wash ware via the washing nozzles 13 with the aid of the
washing pump 11.
[0065] In contrast to a ware washer 40 (cf. FIG. 2) designed as a
programmable machine, by contrast, in a conveyor ware washer the
sprayed washing liquid, after being sprayed, does not, or at least
does not completely, flow back into the washing tank 14 of the
associated washing system 10. Instead, as already indicated,
conveyor ware washers are usually equipped with a cascade system,
via which at least part of the sprayed washing liquid is
transported from treatment zone to treatment zone opposite to the
direction of transport T of the wash ware. The remaining part of
the sprayed washing liquid may be conducted directly into the
prewashing tank 14-1, for example, via a valve 59 and a bypass line
100 (cf. FIG. 1).
[0066] The washing system 10 illustrated in FIG. 3 has at least one
flow sensor 31 which belongs to the sensor device 30 already
mentioned and which is arranged either at the outlet of the washing
pump 11 (cf. ref. 1), upstream of the washing arms 15-1, 15-2 in a
line system 12 (cf. ref. 2), between two washing arms 15-1, 15-2 in
a line system 12 (cf. ref. 3) or in the washing arms 15-1, 15-2
themselves in the immediate vicinity of the washing nozzles 13 (cf.
ref. 4 and ref. 5). The at least one flow sensor 31 is designed to
detect the profile of the volumetric flow rate Q.sub.I in the
washing liquid. The flow rate Q.sub.I to be detected by the flow
sensor 31 is generated in the line system 12 when the washing pump
11 is activated during the washing process, in order preferably to
ensure a virtually constant water circulation capacity.
[0067] The washing pump 11 of the washing system 10 illustrated in
FIG. 3 is switched on and off via a control device 20, illustrated
in FIG. 1 or FIG. 2, of the ware washer 40, 50 (cf. FIGS. 1 and 2).
Furthermore, with the aid of the control device 20, the rotational
speed of the washing pump 11 of the washing system 10 and therefore
the water circulation capacity can advantageously be set.
[0068] As already indicated, the at least one flow sensor 31 of the
washing system 10 belongs to a sensor device 30 which is connected
to the control device 20. With the aid of the control device 20,
the profile, detected by the flow sensor 31, of the flow rate
Q.sub.I in the washing liquid is supplied to the control device
20.
[0069] FIG. 4a illustrates in a diagrammatic and idealized way an
"ideal" (desired) flow rate profile Q.sub.S which is detected by
means of the sensor device 30 and which is generated in the washing
system 10 during fault-free operation of the ware washer 40,
50.
[0070] The switch-on of the washing pump 11, for example on
commencement of the washing process, takes place at a time point
t.sub.0 in the illustration according to FIG. 4a. The desired flow
rate Q.sub.S is a volumetric flow rate which is fixed for a
selected operating state of the ware washer 40, 50 and at which the
washing performance required for the operating state of the ware
washer 40, 50 is achieved.
[0071] As illustrated in FIG. 4a, in fault-free operation of the
ware washer 40, 50 the flow rate Q.sub.I of the washing liquid in
the washing system 10 has adjusted out after the time t.sub.1 at
the desired flow rate Q.sub.S fixed for the set treatment program.
If the flow rate detected by means of the at least one flow sensor
31 of the sensor device 30 does not deviate from the desired flow
rate Q.sub.S over a time interval .DELTA.t.sub.1, then there are no
machine-side problems.
[0072] The (first) time interval .DELTA.t.sub.1 serves, in the
embodiment illustrated in FIG. 4, as a time window for determining
whether a fault-free operation of the ware washer 40, 50 is present
or not. Within the first time interval .DELTA.t.sub.1, the flow
rate Q.sub.I in the washing system 10 is measured continuously with
the aid of the at least one flow sensor 31. It is also conceivable,
however, that, within the time interval .DELTA.t.sub.1, the
hydrostatic flow rate Q.sub.I is measured by predetermined time
points or events, and the measured flow rate values are
subsequently interpolated, in order to obtain a profile of the flow
rate in the time interval .DELTA.t.sub.1.
[0073] Preferably, the time interval .DELTA.t.sub.1 has a set
length, which may be a predetermined or predeterminable (e.g.,
manufacturer, service person or operator programmable or settable)
length, the start of the time interval .DELTA.t.sub.1 being fixed
by a time point t.sub.1 at which the washing pump 11 is switched on
or activated during the washing process in such a way that the
washing liquid is supplied to the at least one washing nozzle 13
via the line system 12. As illustrated in FIG. 4a, the start of the
time interval .DELTA.t.sub.1 lies at a time point t.sub.1 directly
after the expiry of an adjustment time of the flow rate Q.sub.I
generated in the line system 12 after the switch-on of the washing
pump 11. However, it is, of course, also conceivable to select the
start of the time interval .DELTA.t.sub.1 at another time
point.
[0074] The ideal flow rate Q.sub.S to be expected in fault-free
operation of the ware washer 40, 50 is filed in the control device
20 of the ware washer 40, 50, specifically preferably for each
treatment program of the ware washer 40, 50, if different treatment
programs are provided for this and if different water circulation
capacities and desired flow rates are required for the washing
processes of the respective treatment programs, respectively. It
is, of course, also conceivable, however, that the ideal flow rate
profiles Q.sub.S to be expected in fault-free operation of the ware
washer are not filed in the control device 20 itself, but in a
storage device 21 connected to the control device 20, in which case
the control device 20 can have access to the storage device 21, as
required, in order to read out the flow rate profile Q.sub.S ideal
for the washing process to be carried out.
[0075] The ideal flow rate profile Q.sub.S in the washing system 10
which is to be expected in fault-free operation of the ware washer
40, 50 is preferably filed previously in the control device 20 or
storage device 21. It is, of course, also conceivable, however,
that the ideal flow rate profile Q.sub.S is a flow rate profile
which has been detected by the sensor device 30 during an earlier
washing process and filed in the control device 20 or in the
storage device 21. The advantage of this alternative is that, with
the aid of the solution according to the invention, it is possible
to detect whether or not a particularly slowly occurring deviation
of the detected flow rate profile arises in the course of time, as
seen over a plurality of washing processes, and this may serve as
an indicator of, for example, the degree of contamination of the
washing nozzles 13 or as an indicator of the degree of
contamination of a filter device provided, if appropriate, in the
washing system.
[0076] After the flow rate profile Q.sub.I detected over the time
interval .DELTA.t.sub.1 by the sensor device 30 has been supplied
to the control device 20, a comparison takes place between the
detected flow rate profile Q.sub.I and the ideal flow rate profile
Q.sub.S which is filed, for example, in the control device 20 and
which is to be expected in fault-free operation of the ware washer
40, 50. If a deviation of the detected flow rate profile Q.sub.I
from the expected flow rate profile Q.sub.S arises, an analysis of
the deviation takes place automatically in order to determine the
cause of this and to bring about appropriate countermeasures.
[0077] It must be remembered, in this case, that, in determining
whether a deviation from the ideal flow rate profile Q.sub.S is
present or not, a certain deviation range has to be taken into
account. Preferably, in this case, the control device 20 should be
designed in such a way that it finds a deviation from the ideal
flow rate profile Q.sub.S and therefore an operation of the ware
washer 40, 50 which is not fault-free, only when the deviation of
the detected flow rate profile Q.sub.I from the predetermined flow
rate profile Q.sub.S overshoots or undershoots a predetermined or
predeterminable (e.g., manufacturer, service person or operator
programmable or settable) threshold value S.sub.0.
[0078] It is, of course, also conceivable that the flow rate
profile Q.sub.I detected by the sensor device 30 is averaged,
filtered, smoothed or otherwise processed before comparison with
the predetermined (ideal) flow rate profile Q.sub.S.
[0079] In the evaluation of the detected flow rate profile Q.sub.I,
and particularly in the comparison of the detected (and, if
appropriate, processed) flow rate profile Q.sub.I with the
predetermined ideal flow rate profile Q.sub.S, it is determined
whether a deviation from the ideal flow rate profile Q.sub.S is
present or not. However, the present invention is not restricted
only to ascertaining the deviation from the ideal flow rate profile
Q.sub.S; on the contrary, according to the invention, there is
provision, in the presence of a deviation of the detected flow rate
profile Q.sub.I from the predetermined flow rate profile Q.sub.S,
for evaluating the type of deviation so that a conclusion as to the
disturbing influence responsible for this deviation can be drawn.
In the embodiment illustrated, the type of deviation of the
detected flow rate profile Q.sub.I from the ideal flow rate profile
Q.sub.S is to be understood as being, in particular, the size and
time gradient of a difference between the predetermined flow rate
profile Q.sub.S (as minuend) and the detected flow rate profile
Q.sub.I (as subtrahend). In particular, not only is the amount of
the deviation relevant, but also the question as to whether the
detected flow rate Q.sub.I is higher than or lower than the
predetermined flow rate Q.sub.S, and how the time behaviour of the
flow rate profile Q.sub.I appears.
[0080] It is described in detail below, with reference to the
illustrations according to FIGS. 4a to 4f, how, in a preferred
embodiment of the invention, a conclusion can be drawn as to
different disturbing influences on the basis of the type of
deviation of the detected flow rate profile Q.sub.I from the ideal
flow rate profile Q.sub.S illustrated, for example, in FIG. 4a. In
this case, FIGS. 4a to 4f illustrate in a diagrammatic and
idealized way flow rate profiles which have been detected with the
aid of the sensor device 30 in a preferred embodiment of the
invention.
[0081] In this case, it must be remembered that, in the
illustrations according to FIGS. 4b to 4d, the time interval
.DELTA.t.sub.1 (first time interval .DELTA.t.sub.1) serves as a
time window for detecting the actual flow rate profile Q.sub.I. In
the case of the flow rate profiles Q.sub.I illustrated, the first
time interval .DELTA.t.sub.1 commences at the time point t.sub.1
immediately after the expiry of an adjustment time of the flow rate
generated in the line system 12 by the washing pump 11 being
switched on. The end of the first time interval .DELTA.t.sub.1 is
defined by the time point t.sub.2. The time point t.sub.2 is
preferably selected in such a way that a sufficient number of flow
rate measurements can be carried out in the first time interval
.DELTA.t.sub.1 so that reliable evidence of the flow rate Q.sub.I
actually prevailing in the washing system 10 can be obtained. The
time point t.sub.2 depends, in particular, on the sensing rate
achievable by the sensor device 30 or the at least one flow sensor
31 and on the accuracy desired for the detected flow rate profile
Q.sub.I.
[0082] As already indicated, the graph according to FIG. 4a
illustrates the flow rate profile Q.sub.S, such as can be expected
in fault-free operation of the washing system 10. This flow arte
profile Q.sub.S constitutes the ideal or predetermined flow rate
profile. A deviation from this arises when a fault occurs during
operation, that is to say during the washing phase in the washing
system 10. In the graphs according to FIGS. 4b to 4f, the ideal
desired flow rate profile Q.sub.S is illustrated once again as a
dashed curve profile for clearer understanding.
[0083] The basic flow rate profile Q.sub.I illustrated in the graph
according to FIG. 4b is a flow rate profile which is detected with
the aid of the sensor device 30 when a minor leak is present in the
washing system 10. As illustrated, in the time window (first time
interval .DELTA.t.sub.1) taken into account, the detected flow rate
Q.sub.I in the washing system 10 lies slightly above the desired
flow rate Q.sub.S. In the instance illustrated in FIG. 4b, that is
to say when the detected flow rate profile Q.sub.I lies
continuously below the predetermined flow rate profile within the
time window (first time interval .DELTA.t.sub.1) to be taken into
account, and when the amount of the difference between the
predetermined flow rate profile Q.sub.S and the detected flow rate
profile Q.sub.I lies continuously within a range between a first
fixed threshold value S.sub.1 and a second fixed threshold value
S.sub.2, a minor leak in the washing system 10 is concluded
automatically with the aid of the control device 20. In this case,
a corresponding fault warning is generated automatically by the
control device 20 and is issued via the optical and/or acoustic
interface 22 of the ware washer 40, 50, in order to draw the
attention of the operator of the ware washer 40, 50 to the (minor)
leak in the washing system 10.
[0084] Alternatively or additionally to this, it is conceivable
that the control device 20 also automatically generates a
corresponding fault warning and communicates this directly to a
remote maintenance station (remote maintenance service) via the
remote control interface 23 of the ware washer 40, 50.
[0085] As a reaction to the fault warning issued via the
optical/acoustic interface 22 and/or via the remote control
interface 23, appropriate measures can then be introduced by the
ware washer operator or the remote maintenance station in order to
compensate the effect of the detected leak on the washing
performance of the ware washer 40, 50.
[0086] The graph according to the illustration in FIG. 4c is a
basic flow rate profile Q.sub.I which occurs in the event of a
major leak in the washing system 10 or in the event of incorrect or
neglected installation of the washing arms 15-1, 15-2 or in the
event of an absence of washing arm cleaning caps. As illustrated in
FIG. 4c, during the time window (first time interval
.DELTA.t.sub.1) to be taken into account, only a relatively high
flow rate is generated in the washing system 10, which lies below
the second threshold value S.sub.2 and well above the desired flow
rate Q.sub.S and does not approach the desired flow rate Q.sub.S
over the time interval .DELTA.t.sub.1.
[0087] In this case, that is to say when the detected flow rate
value lies continuously above the predetermined flow rate profile
Q.sub.S and the amount of the difference between the predetermined
flow rate profile Q.sub.S and the detected flow rate profile
Q.sub.I is continuously greater than the second fixed threshold
value S.sub.2, a major leak in the washing system 10 is concluded
automatically by the control device 20 and a corresponding fault
warning is issued preferably via the optical and/or acoustic
interface 22 of the ware washer 40, 50 in order to draw the
attention of the operator of the ware washer 40, 50 to a major leak
in the washing system 10.
[0088] So that a differentiation can be made as to whether the
washing flow rate deviation in the washing system detected in the
scenario according to FIG. 4c is the result of a leak or the result
of an incorrect installation of at least one of the washing arms
15-1, 15-2 or the result of the absence of washing arm cleaning
caps, it is basically conceivable to provide suitable washing arm
position sensors, via which corresponding warnings are issued if at
least one of the washing arms 15-1, 15-2 is installed incorrectly
or if washing arm cleaning caps are absent. In this development, a
major leak in the washing system 10 is present when the detected
flow rate profile Q.sub.I lies continuously above the predetermined
flow rate profile Q.sub.S within the first time interval
.DELTA.t.sub.I and the amount of the difference between the
predetermined flow rate profile Q.sub.S and the detected flow rate
profile Q.sub.I is continuously greater than the second fixed
threshold value S.sub.2, and when the washing arm position sensors
issue no fault warning.
[0089] The graph according to the illustration in FIG. 4d shows in
a diagrammatic and idealized way the basic flow rate profile
Q.sub.I which is established in the washing system 10 when one or
more clogged washing nozzles 13 are present. As illustrated in FIG.
4d, in the event of such a fault the flow rate Q.sub.I in the
washing system 10 lies continuously below the desired flow rate
Q.sub.S during the time window .DELTA.t.sub.I to be taken into
account.
[0090] In this case, that is to say when the detected flow rate
profile Q.sub.I lies continuously below the predetermined flow rate
profile Q.sub.S and the amount of the difference between the
predetermined flow rate profile Q.sub.S and the detected flow rate
profile Q.sub.I is continuously greater than a fixed threshold
value S.sub.0 characteristic of the presence of a deviation, the
presence of a blockage in the washing system 10 is concluded
automatically by the control device 20. Consequently, a
corresponding fault warning is issued automatically, preferably via
the optical and/or acoustic interface 22, in order to indicate to
the operator of the ware washer 40, 50 that, for example, at least
one washing nozzle 13 has to be cleaned.
[0091] It is conceivable in this case, that evidence as to the
degree of blockage or the number of nozzles to be cleaned can also
be obtained by means of the amount of the deviation of the detected
flow rate profile Q.sub.I from the predetermined flow rate profile
Q.sub.S.
[0092] The invention is not restricted only to evaluating the
detected (actual) flow rate profile Q.sub.I in the washing system
10 by means of a predetermined (ideal) flow rate profile Q.sub.S at
the commencement of the washing process, that is to say within the
first time interval .DELTA.t.sub.I, so that conclusions as to
possible disturbing influences can be drawn. On the contrary, the
solution according to the invention also covers the detection and
evaluation of the actual flow rate profile Q.sub.I during a second
time interval .DELTA.t.sub.2. The second time interval
.DELTA.t.sub.2 may lie in any desired range during the washing
process.
[0093] In the illustrations according to 4a to 4f, therefore, the
flow rate profile Q.sub.I is not only evaluated in the first time
interval .DELTA.t.sub.1, which preferably lies immediately after
the expiry of the adjustment time of the flow rate generated in the
line system 12 by the washing pump 11 being switched on, but also
in the second time interval .DELTA.t.sub.2, wherein in the graphs
illustrated this second time interval .DELTA.t.sub.2 commences at
the end of the first time interval .DELTA.t.sub.1 (at the time
point t.sub.2) and preferably lasts as long as the washing pump 11
is running.
[0094] Possible flow rate profiles, from which disturbances or
faults occurring during the washing process become clear, are dealt
with below with reference to the graphs according to the
illustrations in FIGS. 4e and 4f.
[0095] The graph according to the illustration in FIG. 4e is a
basic flow rate profile Q.sub.I in the event of leakage occurring
during the washing process. The graph shows that no faults have
occurred during the first time interval .DELTA.t.sub.1. In the
second time interval .DELTA.t.sub.2, the start of which is defined
by the time point t.sub.2 (end point of the first time interval
.DELTA.t.sub.1), the detected flow rate Q.sub.I in the washing
system 10 falls continuously at the time point t.sub.3. In this
case, that is to say when the measured flow rate Q.sub.I falls
continuously within the second time interval .DELTA.t.sub.2 from a
time point t.sub.3 lying in the time window .DELTA.t.sub.2, the
occurrence of a leakage in the washing system 10 is concluded
automatically, preferably after an upper threshold value is
overshot.
[0096] The graph according to the illustration in FIG. 4f shows the
basic flow rate profile Q.sub.I which is established when a
blockage occurs in the washing system 10 during continuous washing
operation (that is to say, within the second time interval
.DELTA.t.sub.2). This is the case, for example, when individual
washing nozzles 13 become at least partially blocked during the
continuous operation of the ware washer 40, 50. In this case, that
is to say when the measured hydrostatic flow rate Q.sub.I decreases
continuously from a time point t.sub.3 during the second time
interval .DELTA.t.sub.2 or during the continuous operation of the
ware washer 40, 50, a blockage of the washing system 10 occurring
only during the continuous operation of the ware washer 40, 50 is
concluded automatically. Consequently, a corresponding fault
warning is issued automatically, preferably via the optical and/or
acoustic interface 22, in order to draw the attention of the
operator of the ware washer 40, 50 to this disturbing factor.
[0097] In a case when, within a time interval .DELTA.t.sub.1,
.DELTA.t.sub.2 during which the flow rate profile is detected, the
measured volumetric flow rate Q.sub.I is reduced due to a blockage
in the washing system 10 (cf. FIGS. 4d and 4f), the process can be
affected as follows: in a ware washer 40 designed as a programmable
machine, the running time of the treatment program shall be
increased, preferably in proportion to the detected flow rate drop.
On the other hand, however, in a ware washer 50 designed as a
conveyor ware washer, the speed at which the washing items to be
treated are transported through the ware washer 50 shall be
decreased preferably in proportion to the detected flow rate drop
thereby increasing the treatment time of the washing items in the
conveyor ware washer.
[0098] In the above-described embodiment of the solution according
to the invention, a ware washer 40, 50 is assumed which has at
least one washing pump (washing pumps 11-1, 11-2, 11-3 in the
conveyor ware washer 50 shown in FIG. 1 and washing pump 11-5 in
the ware washer 40 shown in FIG. 2 and designed as a programmable
machine) and at least one washing nozzle 13-1, 13-2, 13-3, 13-7
which is connected to the washing pump 11-1, 11-2, 11-3, 11-5 via a
line system 12-1, 12-2, 12-3, 12-5 and to which a washing liquid is
supplied during a washing process by the washing pump 11-1, 11-2,
11-3, 11-5 being activated, during the washing process the profile
Q.sub.I of the flow rate of the washing liquid in the line system
12-1, 12-2, 12-3, 12-5 being detected and being compared with a
predetermined flow rate profile Q.sub.S.
[0099] Alternatively or additionally to this, however, it is also
conceivable, during a final rinse process, to detect the profile
Q.sub.I of the flow rate of the final rinse liquid supplied to the
nozzles 13-4, 13-5, 13-6 provided for final rinse and to compare it
with a predetermined flow rate profile Q.sub.S.
[0100] In this case, it must be remembered that the conveyor ware
washer 50 illustrated, for example, in FIG. 1 has a final rinse
pump 11-4 and final rinse nozzles 13-4, 13-5 connected to the final
rinse pump 11-4 via the line system 12-4. During a final rinse
process, final rinse liquid is supplied to the final rinse nozzles
13-4, 13-5 by the final rinse pump 11-4 being activated. In order
to achieve a situation where, during the final rinse process, the
profile Q.sub.I of the flow rate of the final rinse liquid in the
line system 12-4 can be detected and compared with a predetermined
flow rate profile Q.sub.S, in the conveyor ware washer 50
illustrated in FIG. 1 a sensor device 30' is provided, having at
least one pressure sensor 31' which may be arranged, for example,
at the outlet of the final rinse pump 11-4 or in the line system
12-4 in the immediate vicinity of the final rinse nozzles 13-4,
13-5. The at least one pressure sensor 31' is designed to detect
the profile of the volumetric flow rate Q.sub.I in the final rinse
liquid. The flow rate Q.sub.I to be detected by the flow sensor 31'
is generated in the line system 12-4 when the final rinse pump 11-4
is activated during the final rinse process.
[0101] The final rinse pump 11-4 of the conveyor ware washer 50
illustrated in FIG. 1 is switched on and off via the control device
20 of the ware washer 50. Furthermore, with the aid of the control
device 20, the rotational speed of the final rinse pump 11-4 and
therefore the quantity of final rinse liquid supplied per unit time
for the final rinse nozzles 13-4, 13-5 can advantageously be
set.
[0102] On the other hand, it is, of course, also conceivable, in
the ware washer 40 illustrated in FIG. 2 and designed as a
programmable machine, during a final rinse process to detect the
profile Q.sub.I of the flow rate of the final rinse liquid supplied
to the final rinse nozzles 13-6 provided for final rinse and to
compare it with a predetermined flow rate profile Q.sub.S. In this
case, it must be remembered that, in the embodiment, illustrated in
FIG. 2, of the ware washer 40 designed as a programmable machine, a
final rinse pump 11-6 is provided which is connected with its
suction side to an outlet of a water heater (boiler) 60. The water
heater 60 has an inlet connected to a fresh water supply line 61.
The fresh water supply line 61 is connectable to further fresh
water supply lines 63, 64 via a valve 62, so that either fresh
water or fresh water with added rinse agent can be supplied to the
water heater 60. The water heater 60 has a heating system, so that
the liquid (pure fresh water or fresh water with added rinse agent)
supplied via the inlet can be heated in accordance with a process
flow.
[0103] Via the final rinse pump 11-6 connected with its suction
side to the outlet of the water heater 60, the final rinse liquid
optionally heated in the water heater 60 or unheated can be routed,
for example during a final rinse phase, to the final rinse nozzles
13-6 via a final rinse line system 12-6. The final rinse nozzles
13-6 are arranged in the treatment chamber 41, in order to spray
the final rinse liquid heated in the water heater 60 onto the wash
ware in the treatment chamber 41. It is, of course, also
conceivable, however, that the water heater 60 is supplied with
pure fresh water, to which a rinse agent is added only after
heating in the water heater 60.
[0104] The solution according to the invention is not restricted to
the presence of a water heater 60. On the contrary, within the
scope of the invention, the provision of a water heater 60 may even
be dispensed with, so that, during a final rinse process, unheated
final rinse liquid is conveyed to the final rinse nozzles 13-6
arranged in the treatment chamber 41 and is sprayed onto the wash
ware.
[0105] In the embodiment, illustrated diagrammatically in FIG. 2,
of the ware washer 40 designed as a programmable machine, the
washing nozzles 13-7 and the final rinse nozzles 13-6 are in each
case preferably arranged above and below the wash ware region and
are directed toward the wash ware region of the treatment chamber
41. In particular, in the embodiment illustrated, a downwardly
directed upper washing nozzle system and a likewise downwardly
directed upper final rinse nozzle system, formed separately from
this, and also an upwardly directed lower washing nozzle system and
a likewise upwardly directed lower final rinse nozzle system,
formed separately from this, are provided. It is, of course, also
conceivable, however, to provide an upper and a lower washing
nozzle system which serve jointly for the spraying of washing
liquid (during a washing phase) and for the spraying of final rinse
liquid (during a final rinse phase). Also, the washing nozzles 13-7
and/or the final rinse nozzles 13-6 may be arranged only at the top
or only at the bottom, instead of at the bottom and top, or,
instead or additionally, may also be arranged on one side of the
treatment chamber 41 and be directed into the wash ware region
transversely with respect to the treatment chamber 41.
[0106] During a final rinse process, in the embodiment, illustrated
diagrammatically in FIG. 2, of the ware washer 40 designed as a
programmable machine, final rinse liquid is supplied to the final
rinse nozzles 13-6 by the final rinse pump 11-6 being activated. In
order to achieve the situation where, during the final rinse
process, the profile Q.sub.I of the flow rate of the final rinse
liquid in the line system 12-6 can be detected and compared with a
predetermined flow rate profile Q.sub.S, in the ware washer 40
illustrated in FIG. 2 a sensor device 30'' is provided, having at
least one flow sensor 31'' which may be arranged, for example, at
the outlet of the final rinse pump 11-6 or in the line system 12-6
between the final rinse pump 11-6 and the final rinse nozzles 13-6.
The at least one flow sensor 31'' is designed to detect the profile
of the hydrostatic flow rate Q.sub.I in the final rinse liquid. The
flow rate Q.sub.I to be detected by the flow sensor 31'' is
generated in the line system 12-6 when the final rinse pump 11-6 is
activated during the final rinse process.
[0107] The final rinse pump 11-6 of the ware washer 40 illustrated
in FIG. 2 is switched on and off via the control device 20 of the
ware washer 40. Furthermore, with the aid of the control device 20,
the rotational speed of the final rinse pump 11-6 and therefore the
quantity of final rinse liquid supplied per unit time to the final
rinse nozzles 13-6 can advantageously be set.
[0108] FIGS. 5a to 5f illustrate flow rate profiles which were
recorded, in the conveyor ware washer according to FIG. 1, with the
aid of the sensor device 30' or, in the ware washer 40 designed as
a programmable machine, with the aid of the sensor device 30'' and
which correspond respectively to the flow rate profile of the
volumetric flow rate of the final rinse liquid in the line system
12-4 and to the flow rate profile of the volumetric flow rate of
the final rinse liquid in the line system 12-6 during a final rinse
process. The flow rate profiles illustrated in FIGS. 5a to 5f for
the final rinse system largely correspond in profile and indication
to the flow rate profiles in the washing system which are explained
in FIGS. 4a to 4f. The observations explained there for the washing
system may be transferred similarly to the final rinse system, and
in this case the flow rate profiles of the liquids in the washing
system may differ from those in the final rinse system, where
appropriate, in their amplitudes (desired flow rate Q.sub.S,
detected flow rate Q.sub.I, threshold values S.sub.0, S.sub.1,
S.sub.2).
[0109] The invention is not restricted to the embodiments shown by
way of example in the drawings. On the contrary, the invention may
be gathered from an overall consideration by a person skilled in
the art of the patent claims and of the description of the
exemplary embodiments.
[0110] Thus, it is, of course, conceivable that the start of the
second time interval .DELTA.t.sub.2 illustrated in FIGS. 4a to 4f
does not coincide with the end (time point t.sub.2) of the first
time interval .DELTA.t.sub.1. In particular, it is conceivable that
the second time interval .DELTA.t.sub.2, like the first time
interval .DELTA.t.sub.1, commences even immediately after the
expiry of the settling time of the flow rate which is generated in
the washing system 10 when the washing pump 11 is switched on.
[0111] On the other hand, it is nevertheless conceivable that the
profile of the flow rate Q.sub.I is detected with the aid of the
sensor device 30, 30', 30'', in that the flow rate is measured
continuously during the entire washing and/or final rinse process,
or in that the flow rate is measured at predetermined or
predeterminable time points or events during the entire washing
and/or final rinse process, and the measured flow rate values are
interpolated.
[0112] The solution according to the invention makes it possible
automatically to ascertain and evaluate a deviation of the flow
rate profile Q.sub.I prevailing in the washing system and/or final
rinse system from an ideal prefixed flow rate profile Q.sub.S, in
order to record disturbances or faults which are responsible for
the flow rate deviation and which either are present even at the
commencement of the washing process or first arise during the
washing or final rinse process. Suitable measures are taken
automatically as a function of the type of disturbance, in order
either to maintain the desired washing performance of the ware
washer or, if this is not possible, to maintain the operation of
the ware washer, without entailing the risk of damage occurring on
the ware washer.
* * * * *