Note: Descriptions are shown in the official language in which they were submitted.
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SYSTEM FOR WASHING WASHWARE AND
METHOD FOR OPERATING A SYSTEM OF THIS TYPE
The invention relates to a system for washing washware,
comprising at least one conveyor dishwasher having at least
one wash zone, at least one final-rinse zone and a
transportation apparatus for transporting washware through
the individual treatment zones of the conveyor dishwasher,
and a conveyor system for feeding washware to the at least
one conveyor dishwasher. The invention also relates to a
method for operating a dishwashing system of this type.
The invention accordingly relates, in particular, to a
dishwashing system having a flight-type dishwasher (flight-
type warewasher) or a rack-conveyor dishwasher (rack-conveyor
warewasher), in which the washware to be treated, for example
dishes, pots and pans, glasses, cutlery, trays and other
utensils to be cleaned, is fed to the conveyor dishwasher
with the aid of a conveyor system.
Semi-automated dishwashing systems, in which the dishes are
returned via a conveyor system which has, for example, a feed
conveyor belt or the like for feeding washware to the
conveyor dishwasher, are increasingly being used in
relatively large catering establishments in particular. The
conveyor system may be in the form, for example, of a tray-
return belt onto which trays with dishes or the dishes can be
directly placed at a dish-receiving point and from there fed
to the conveyor dishwasher either directly or via a manual
pre-clearing station or pre-sorting station. It goes without
saying that other solutions are also feasible for the
conveyor system.
Conveyor dishwashers (conveyor warewashers) are used in the
commercial field. In contrast to domestic dishwashers, in
which the washware to be cleaned remains stationary in the
machine during cleaning, in the case of conveyor dishwashers,
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the washware is transported through various treatment zones
of the machine. In the case of conveyor dishwashers, the
washware is conveyed through a plurality of treatment zones,
for example a pre-wash zone or zones, a main-wash zone or
zones, a post-wash or pre-rinse zone or zones, a final-rinse
zone or zones and a drying zone or zones. A transportation
apparatus which generally has compartments for accommodating
washware is used to transport the washware through the
conveyor dishwasher in a transportation direction. In the
case of a flight-type dishwasher, the compartments may be
formed by supporting fingers on a transportation belt of the
transportation apparatus. In rack-conveyor dishwashers, dish
racks in which compartments can be formed for accommodating
the washware to be treated serve as the transportation
apparatus. It is feasible here for the dish racks to be
transported through the rack-conveyor dishwasher by a
conveyor device.
DE 196 08 030 Cl describes a system for washing washware
having a conveyor dishwasher in which the process parameters
of the individual treatment zones (pre-wash zone, main-wash
zones and possibly final-rinse zone) can be matched to the
respective washware during operation, so that the washware
can be cleaned in an effective and economical manner. In the
case of this conventional conveyor dishwasher, a total of two
different types of washware are taken into consideration,
specifically "drinking glasses, plates, trays" on the one
hand and "pots and pans, containers, tubs" on the other hand.
Furthermore, the degree of soiling of the washware to be
treated plays a role when selecting the process parameters.
DE 10 2005 021 101 Al discloses a system for washing washware
having a conveyor dishwasher in which the final-rinse zone
has two spray arms which are separate from one another. At
least one of the two spray arms is switched on or switched
off as required. The additional spray arm in the final-rinse
zone is switched on or switched off either as a function of
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the transportation speed or as a function of the type of
washware, the quantity of washware and the degree of soiling
of the washware.
US 6,530,996 B2 relates to a system for washing washware
having a conveyor dishwasher, in which a wash and/or final-
rinse program is automatically selected as a function of the
type of washware. In particular, the transportation speed and
the spray time are varied as a function of the type of
washware.
The aim of the invention is to achieve the object of
developing a system for washing washware of the type
mentioned in the introduction such that - in comparison to
the dishwashing systems known from the prior art - the
consumption of fresh water, chemicals and energy can be
further reduced during operation. A further aim is to specify
a method for operating a dishwashing system of this type.
The number of units of washware which are fed to the at least
one conveyor dishwasher with the aid of the conveyor system
per unit time can be determined by virtue of the provision of
a washware detector apparatus which detects the presence of
washware in a prespecified or prespecifiable region of the
conveyor system. In this way, the operating load on the
dishwashing system can be detected and the expected degree of
utilization of the conveyor dishwasher or dishwashers can be
predicted. This permits the operating parameters of the
conveyor dishwasher or dishwashers to be matched to the
amount of washware in good time, since it is already known in
advance how many units of washware will soon have to be
treated in the at least one conveyor dishwasher.
The dishwashing system according to the invention accordingly
also has a control device which automatically selects a
predefined or predefinable (e.g, set or stored in memory of
the control device by being preset during machine manufacture
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and/or subject to on-site adjustment by a service person or
machine operator according to the particular needs of the
machine installation) treatment program and sets the process
parameters associated with the selected treatment program as
a function of the detected number of units of washware which
are fed to the at least one conveyor dishwasher with the aid
of the conveyor system per unit time for the at least one
conveyor dishwasher. Since the number of units of washware
which are fed to the conveyor dishwasher per unit time is
determined by the washware detector apparatus which detects
the presence of washware in a prespecified or prespecifiable
region of the conveyor system, the expected degree of
utilization of the conveyor dishwasher is already known in
advance. A certain lead time is accordingly provided with
respect to setting process parameters in the conveyor
dishwasher, this lead time possibly being necessary to change
or adapt certain process parameters.
This is particularly true when, for example, the quantity of
wash liquid sprayed in the at least one wash zone of the
conveyor dishwasher per unit time and/or the quantity of
final-rinse liquid sprayed in the at least one final-rinse
zone per unit time is to be matched to the degree of
utilization of the conveyor dishwasher. Under certain
circumstances, these process parameters can be changed only
with a time delay, since a certain lead term is required so
that the spray jets fan out properly in the at least one wash
zone or in the at least one final-rinse zone and therefore
effective treatment of the washware in the wash zone or in
the final-rinse zone can be guaranteed.
Since a predefined or predefinable program sequence is
automatically selected and the process parameters associated
with the selected program sequence are set for the conveyor
dishwasher as a function of the expected degree of
utilization of the conveyor dishwasher by means of the
solution according to the invention, it is ensured that the
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control device can always select and set the optimum
operating parameters for treating the washware. The "optimum
process parameters" are to be understood to be process
parameters with which the washware is treated not only in an
effective manner but also in a particularly economical manner
in the individual treatment zones of the conveyor dishwasher.
In a preferred embodiment of the solution according to the
invention, at least one of the process parameters listed
below is automatically set or changed as a function of the
detected number of units of washware which are fed to the
conveyor dishwasher per unit time:
- the transportation speed at which the washware
is transported through the individual
treatment zones of the conveyor dishwasher;
- a quantity of wash liquid sprayed in the at
least one wash zone of the conveyor dishwasher
per unit time;
- a quantity of final-rinse liquid sprayed in
the at least one final-rinse zone of the
conveyor dishwasher per unit time;
- a temperature value of an air stream used to
dry the washware in a drying zone of the
conveyor dishwasher; and/or
- a volumetric quantity of a drying-air stream
circulating in a drying zone of the conveyor
dishwasher for drying the washware per unit
time.
In addition or as an alternative to this, it is further
preferred when, in this embodiment of the dishwashing system
according to the invention, at least one conveyor dishwasher
is provided which has a first main-wash zone, with main-wash
nozzles, and a second main-wash zone, likewise with main-wash
nozzles, which is connected downstream of the first main-wash
zone, with the control device being designed to automatically
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switch on or switch off either the supply of wash liquid to
the main-wash nozzles of the first main-wash zone or the
supply of wash liquid to the main-wash nozzles of the second
main-wash zone (switch-on and switch-off of wash zones) as a
function of the detected number of units of washware which
are fed to the at least one conveyor dishwasher per unit
time.
Since not only the quantity of wash liquid which is sprayed
per unit time or the quantity of final-rinse liquid which is
sprayed per unit time, but additionally also the
transportation speed, are changed, this can have the effect
that the contact time of the washware in the respective
treatment zones of the conveyor dishwasher is no longer than
would actually be necessary for adequate treatment.
Overtreatment of the washware is therefore prevented.
In the dishwashing system according to the invention, in
principle only as many resources of water, energy and
chemicals are accordingly consumed in the respective
treatment zones of the conveyor dishwasher as are actually
necessary to ensure adequate processing (cleaning, final-
rinsing, drying). In particular, the consumption of fresh
water, which is sprayed onto the washware in the final-rinse
zone of the conveyor dishwasher in pure form or with further
additives added, can be markedly reduced during operation of
the dishwashing system.
In one possible embodiment of the dishwashing system
according to the invention, it is feasible for the process
parameters of a first treatment program, for example the
process parameters for partial-load operation, to be
automatically set up to a predefined or predefinable number
of units of washware which are fed with the aid of the
conveyor system per unit time in the conveyor dishwasher, and
for the process parameters of a second treatment program, for
example the process parameters for full-load operation, to be
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automatically set when the predefined or predefinable number
of units of washware which are fed with the aid of the
conveyor system per unit time in the conveyor dishwasher is
exceeded. In this preferred embodiment too, the settable
process parameters preferably include at least one of the
following parameters: the transportation speed at which the
washware is transported through the individual treatment
zones of the conveyor dishwasher; the quantity of wash liquid
sprayed in the at least one wash zone per unit time; and/or
the quantity of final-rinse liquid sprayed in the at least
one final-rinse zone per unit time.
It is therefore feasible, in particular, for the
transportation speed during partial-load operation, that is
to say when the process parameters of the first treatment
program are set, to be reduced compared to full-load
operation, while at the same time both the quantity of wash
liquid which is sprayed in the at least one wash zone of the
conveyor dishwasher per unit time and the quantity of final-
rinse liquid which is sprayed in the at least one final-rinse
zone of the conveyor dishwasher per unit time are likewise
reduced compared to full-load operation.
The method according to the invention is a solution for
operating a system for washing washware which has at least
one conveyor dishwasher and a conveyor system for feeding
washware to the at least one conveyor dishwasher. The method
according to the invention can be used to reduce the
consumption, in particular, of fresh water during operation
of a dishwashing system of this type in a manner which is
particularly easy to implement but is nevertheless effective.
The invention will be described below on the basis of a
preferred embodiment as an example and with reference to the
drawings, in which:
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Fig 1 schematically shows a plan view of a system for
washing washware according to the invention; and
Fig. 2 schematically shows a longitudinal sectional view
through a conveyor dishwasher which is used in the
system according to Fig. 1.
Fig. 1 schematically shows a plan view of an embodiment of
the dishwashing system 100 according to the invention. This
is accordingly a semi-automated dishwashing system which has
a first conveyor dishwasher 2 for washing dishes, glasses and
pots and pans, and also a second conveyor dishwasher 2' for
washing trays and items of cutlery. A conveyor system 101 is
also provided. The conveyor system 101 extends from a
washware-receiving region 103 to the second conveyor
dishwasher 2' and serves to convey washware from the
washware-receiving region 103 to the inlet region 11' of the
second conveyor dishwasher 2'.
The washware is preferably fed to the conveyor dishwasher 2'
at a constant rate of advance. Furthermore, the
abovementioned first conveyor dishwasher 2 is provided in the
outlet region of the conveyor system 101. In the illustrated
embodiment, this first conveyor dishwasher 2 serves to wash
dishes, for example plates, cups, saucers, bowls and
containers and vessels. The design and the manner of
operation of the second conveyor dishwasher 2' which is used
in the dishwashing system 100 according to Fig. 1 will be
described below with reference to the illustration in Fig. 2.
The first conveyor dishwasher 2, which serves to wash dishes,
glasses and pots and pans, is, in principle, of identical
design to the second conveyor dishwasher 2', but with not
only one main-wash zone 14', but two main-wash zones 14a, 14b
which are arranged one behind the other, being provided here.
A single main-wash zone 14' is sufficient in the second
conveyor dishwasher 2' since the types of washware to be
treated in the second conveyor dishwasher 2' are generally
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not heavily soiled and therefore a plurality of main-wash
zones are not needed.
Identically acting components are denoted by the same
reference numerals in the first conveyor dishwasher 2 and the
second conveyor dishwasher 2', with the reference numerals
associated with the treatment zones of the second conveyor
dishwasher 2' being provided with an apostrophe in order to
draw a distinction. The manner of operation of the second
conveyor dishwasher 2' will be described below with reference
to the illustration according to Fig. 2. These explanations
apply in an equivalent sense to the manner of operation of
the first conveyor dishwasher 2 too.
The washware which is transported to the two conveyor
dishwashers 2, 2' with the aid of the conveyor system 101 is
pre-sorted with respect to the type of washware in a pre-
sorting region 104. In detail, provision is made here for the
washware which is to be treated in the first conveyor
dishwasher 2 (glasses and dishes) to be moved manually from
the conveyor system 101 onto the transportation apparatus 4
of the first conveyor dishwasher 2 in the pre-sorting region
104. This ensures that only trays and cutlery are fed to the
second conveyor dishwasher 2' with the aid of the conveyor
system 101.
The dishwashing system 100 according to the present invention
is distinguished in that a washware detector apparatus 51 is
provided which is designed to detect the presence of washware
in a prespecified or prespecifiable region of the conveyor
system 101. In the preferred embodiment according to Fig. 1,
the conveyor system 101 is designed such that the washware is
fed to the two conveyor dishwashers 2, 2' at a predefined or
predefinable feed rate. In this way, the washware detector
apparatus 51 is also suitable for detecting the number of
units of washware which are fed to the conveyor dishwashers
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2, 2' with the aid of the conveyor dishwasher 101 per unit
time.
The washware detector apparatus 51 preferably has at least
one optically, inductively or capacitively operating detector
device 51' which is designed to detect the presence of
washware in the prespecified or prespecifiable region of the
conveyor system 101. It is particularly advantageous when the
detector device 51' is designed to detect the presence of
individual trays, individual dishes, individual pots and
pans, individual glasses, individual items of cutlery and/or
individual containers.
In the dishwashing system 100 illustrated in Fig. 1, a
control device 50 is also provided, which is designed to
automatically select a predefined or predefinable treatment
program and set the process parameters associated with the
selected treatment program for at least one of the two
conveyor dishwashers 2, 2' as a function of the detected
number of items of washware fed to the two conveyor
dishwashers 2, 2' per unit time.
It is preferred here when the control apparatus 50 is
designed to set the process parameters, which are associated
with the selected treatment program, with a time delay in the
at least one conveyor dishwasher 2, 2', with the time delay
depending on the distance of the region of the conveyor
system 101 monitored by the detector device 51' from the at
least one conveyor dishwasher 2, 2' and on the feed rate at
which the washware is fed to the at least one conveyor
dishwasher 2, 2'.
The exact manner of operation of the control device 50 is to
be described in conjunction with the conveyor dishwasher 2'
which is schematically illustrated in Fig. 2.
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Fig. 2 schematically shows a longitudinal sectional view
through the second conveyor dishwasher 2' which is used to
wash trays and cutlery in the dishwashing system according to
Fig. 1. The conveyor dishwasher 2' is equipped with a
transportation apparatus 4' for transporting washware (not
illustrated) through the conveyor dishwasher 2' in a
transportation direction 8. The conveyor dishwasher 2' has at
least one wash zone, for example as illustrated in Fig. 2, a
pre-wash zone 12' and a main-wash zone 14' which is arranged
downstream of the pre-wash zone 12' as seen in the
transportation direction 8.
A post-wash zone 16' is arranged downstream of the at least
one wash zone 12', 14' as seen in the transportation
direction 8, and at least one final-rinse zone, for example
only a single final-rinse zone 18' as illustrated, is
arranged downstream of the post-wash zone 16'. In the
conveyor dishwasher 2' illustrated in Fig. 2, a drying zone
40' follows the final-rinse zone 18' in the transportation
direction 8 of the washware. The respective zones 12', 14',
16', 18', 40' of the conveyor dishwasher 2' can be separated
from one another by means of separating curtains 47. In the
embodiment illustrated in Fig. 2, the inlet tunnel 10' itself
is also separated from the inlet 11' by means of a separating
curtain 47. Wash liquid and final-rinse liquid are prevented
from splashing over and vapours are prevented from escaping
from the conveyor dishwasher 2' by virtue of the provision of
the separating curtains 47.
Spray nozzles 20, 22, 24, 26, 28, 30 are associated with the
said treatment zones 12', 14', 16', 18' of the conveyor
dishwasher 2'. These spray nozzles 20, 22, 24, 26, 28, 30
serve to spray liquid onto the washware when the said
washware is transported through the respective treatment
zones 12', 14', 16', 18' by the transportation apparatus 4'.
The individual spray systems of the treatment zones 12', 14',
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16', 18' ensure that the washware to be treated is sprayed
both from above and from below.
However, in the conveyor dishwasher 2' which is schematically
illustrated in Fig. 2, the final-rinse zone 18' not only has
downwardly directed upper spray nozzles 20 and upwardly
directed lower spray nozzles 22, but also transversely
directed lateral spray nozzles 24 on each side of the
transportation apparatus 4'. The use of lateral spray nozzles
24 permits targeted spraying of areas of the washware with a
final-rinse liquid in shadow zones too. The use of lateral
spray nozzles 24 in the final-rinse zone 18' has a clear
advantage in terms of the final-rinse result (effective
rinsing of detergent residues from surfaces of the washware
in shadow zones too) over systems in which only upper and
lower spray nozzles 20, 22, and no transversely directed
lateral spray nozzles 24, are provided in the final-rinse
zone 18', specifically when the transportation system is
fully loaded, that is to say, for example, when the tray
carrier is loaded with one tray next to another.
The post-wash zone 16', main-wash zone 14' and pre-wash zone
12' also have associated tanks (post-wash tank 32, main-wash
tank 34, pre-wash tank 36) for accommodating sprayed liquid
and/or for providing liquid for the spray nozzles 26, 28, 30
of the relevant treatment zones 14', 16', 18'.
As already mentioned, the first conveyor dishwasher 2, in the
dishwashing system 100 illustrated in Fig. 1, likewise has a
transportation apparatus 4 for transporting washware (not
illustrated) through the conveyor dishwasher 2 in the
transportation direction 8. The first conveyor dishwasher 2
also has a pre-wash zone 12 and a (first) main-wash zone 14a,
which is arranged downstream of the pre-wash zone 12 as seen
in the transportation direction 8, downstream of an inlet
tunnel 10 as seen in the transportation direction 8. In
contrast to the second conveyor dishwasher 2' according to
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Fig. 2, a further (second) main-wash zone 14b is provided
downstream of the (first) main-wash zone 14a as seen in the
transportation direction 8 in the first conveyor dishwasher
2. A post-wash zone 16 is arranged downstream of the second
main-wash zone 14b as seen in the transportation direction 8,
and at least one final-rinse zone, for example only a single
final-rinse zone 18 as illustrated, is arranged downstream of
the post-wash zone 16. In the first conveyor dishwasher 2
which is illustrated in plan view only in Fig. 1, a drying
zone 40 follows the final-rinse zone 18 in the transportation
direction 8 of the washware.
The treatment zones 10, 12, 14a, 14b, 16 and 18 of the first
conveyor dishwasher 2 are identical to the corresponding
treatment zones 10', 12', 14', 16' and 18' in terms of
function and structure, and so the treatment zones 10, 12,
14a, 14b, 16 and 18 of the first conveyor dishwasher 2 are
not described in detail.
As already indicated, final-rinse liquid, which comprises
fresh water together with rinse aid which is added in a
metered manner, is sprayed onto the washware (not
illustrated) via the spray nozzles 20, 22, 24 of the final-
rinse zone 18', which spray zones are arranged above and
below the transportation apparatus 4' and also laterally, in
the second conveyor dishwasher 2' illustrated in Fig. 2. Some
of the sprayed final-rinse liquid is transported from
treatment zone to treatment zone, counter to the
transportation direction 8 of the washware, by means of a
cascade system. The remainder of the final-rinse liquid which
is sprayed in the final-rinse zone 18' is conducted directly
into the pre-wash tank 36 which is associated with the pre-
washed zone 12' via a valve V1 and a bypass line 38.
In the cascade system, the final-rinse liquid which is
sprayed by the final-rinse nozzles 20, 22, 24 flows from the
final-rinse zone 18' into the post-wash tank 32, which is
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associated with the post-wash zone 16', due to the force of
gravity. The final-rinse liquid which is sprayed in the
final-rinse zone 18' and collected by the post-wash tank 32
is then conveyed to the spray nozzles (post-wash nozzles 26)
of the post-wash zone 16' with the aid of a post-wash pump
45.
Wash liquid is rinsed off from the washware in the post-wash
zone 16'. The liquid produced in the process (post-wash
liquid) flows into the main-wash tank 34, which is associated
with the main-wash zone 14', due to the force of gravity. An
outflow element 39, for example an outflow base or a baffle
plate which conducts the post-wash liquid, which is sprayed
by the post-wash nozzles 26, into the main-wash tank 34, is
preferably provided for this purpose. According to another
embodiment (not shown), the outflow element 39 can be
dispensed with when the main-wash tank 34 extends as far as
beneath the post-wash nozzles 26 of the post-wash zone 16'.
The liquid accommodated by the main-wash tank 34 of the main-
wash zone 14' is usually provided with a detergent and is
sprayed onto the washware via the spray nozzles (main-wash
nozzles 28) of the main-wash zone 14' with the aid of a main-
wash pump 35. The wash liquid sprayed by the main-wash
nozzles 28 flows back into the main-wash tank 34 due to the
force of gravity.
The main-wash tank 34 forms a fluid connection with the pre-
wash tank 36, which is associated with the pre-wash zone 12',
via an overflow line 37. The wash liquid which is sprayed in
the main-wash zone 14' enters the pre-wash tank 36 via this
overflow line 37 when a sufficient quantity of wash liquid is
accommodated in the main-wash tank 34.
The liquid accommodated in the pre-wash tank 36 of the pre-
wash zone 12' is then sprayed onto the washware via the spray
nozzles (pre-wash nozzles 30) of the pre-wash zone 12' with
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the aid of a pre-wash pump 33, in order to remove coarse
particles of dirt from the washware. The wash liquid which is
sprayed by the pre-wash nozzles 30 flows back into the pre-
wash tank 36 due to the force of gravity.
The pre-wash tank 36 is provided with an overflow line 31
which serves to feed the excess quantity of liquid to a
wastewater system when a liquid level in the pre-wash tank 36
is exceeded.
As already indicated, the liquid which is sprayed in the
main-wash zone 14' and in the pre-wash zone 12' preferably
contains detergent which is added in a metered manner, for
example, to the liquid which is accommodated in the main-wash
tank 34 of the main-wash zone 14' with the aid of a
detergent-metering apparatus (not shown in the drawings).
As already mentioned, the drying zone 40' follows the final-
rinse zone 18' in the transportation direction 8. The
washware is dried with dry and heated air in the drying zone
40', in order to blow off or dry off the moisture on the
washware. In order to keep the moisture content of the air in
a range which is favourable for drying purposes, it is
feasible, for example, to feed ambient air from the outside
to the drying zone 40' via an opening, for example through
the outlet opening for the washware.
The warm and moist air in the drying zone 40' is then drawn
out of the drying zone 40' via a further opening with the aid
of a fan 41, for example. In this case, it is advantageous
when the discharge-air stream out of the drying zone 40'
passes a heat-recovery device 42 in which a condenser may be
provided, for example. The heat-recovery device 42 serves to
recover at least some of the thermal energy contained in the
discharge air.
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The first conveyor dishwasher 2 has a drying zone 40 which
corresponds to the drying zone 40'.
If the tanks (pre-wash tank 36, main-wash tank 34, post-wash
tank 32) which are associated with the wash zones 12', 14'
and 16' are empty or only inadequately filled before the
conveyor dishwasher 2' is first started, the said tanks first
have to be filled via a fresh-water line 90 and/or by
spraying final-rinse liquid into the final-rinse zone 18'.
The fresh-water line 90 can be connected to a fresh-water
supply system via a controllable valve V3. The quantity of
wash liquid available in the main-wash zone 14' and in the
pre-wash zone 12' can in each case be monitored with the aid
of a level sensor which is provided in the main-wash tank 34
and respectively with the aid of a level sensor which is
provided in the pre-wash tank 36, and reported to a control
apparatus 50.
The final-rinse zone 18' can - as illustrated in Fig 2 - have
an associated fresh-water container 30 for buffer-storing at
least some of the fresh water provided for final rinsing. The
fresh-water container 30 is provided at one end with a fresh-
water connection, which can be connected to a fresh-water
supply system via a controllable fresh-water feed valve V2,
and at the other end to the intake side of a final-rinse pump
43. However, it goes without saying that it is also feasible
to dispense with a fresh-water container 30 for buffer-
storing at least some of the fresh water provided for final
rinsing, and to connect the fresh-water feed valve V2
directly to the intake side of the final-rinse pump 43.
The pressure side of the final-rinse pump 43 is connected to
a water heater 9 (boiler) via a line system. In this case,
the line system is designed in such a way that the liquid
conveyed to the spray nozzles 20, 22, 24 of the final-rinse
zone 18' by the final-rinse pump 43 passes the heat-recovery
device 42 before it reaches the water heater 9. In this way,
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it is possible to make use of at least some of the thermal
energy of the discharged discharge air to heat the liquid fed
to the spray nozzles 20, 22, 24 of the final-rinse zone 18'.
Rinse aid is added in a metered manner to the fresh water,
which is fed to the final-rinse pump 43 either directly by
the fresh-water feed valve V2 or by the fresh-water container
30, with the aid of a rinse aid-metering apparatus (not
explicitly illustrated in Fig. 2).
The control device 50, which has already been described in
conjunction with the dishwashing system 100 illustrated in
Fig. 1, is schematically illustrated in the second conveyor
dishwasher 2' illustrated in Fig. 2. The control device 50 is
designed to automatically set specific process parameters as
a function of the number of units of washware which are fed
to the conveyor dishwashers 2, 2' with the aid of the
conveyor system 101 per unit time, the said number of units
of washware being detected with the aid of the washware
detector apparatus 51. The control device 50 is preferably
designed to control the different controllable components of
the conveyor dishwashers 2, 2', for example the respective
pumps and valves, in accordance with a predefined or
predefinable program sequence, in order to thus be able to
set the process parameters in the individual treatment zones
12, 14a, 14b, 16, 18 or 12', 14', 16', 18' of the conveyor
dishwasher 2 or 2' and also the transportation speed of the
transportation apparatus 4 or 4'.
The control device 50 is preferably designed to automatically
set the transportation speed, at which the washware is
transported through the individual treatment zones 12, 14a,
14b, 16, 18 or 12', 14', 16', 18' of the conveyor dishwasher
2 or 2', to a predefined or predefinable value as a function
of the detected number of units of washware which are fed to
the conveyor dishwashers 2, 2' per unit time; and/or to
automatically set a quantity of wash liquid sprayed in the at
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least one wash zone 12, 14a, 14b or 12', 14' per unit time to
a predefined or predefinable value as a function of the
detected number of units of washware which are fed to the
conveyor dishwashers 2, 2' per unit time; and/or to
automatically set a quantity of final-rinse liquid sprayed in
the final-rinse zone 18 or 18' of the conveyor dishwasher(s)
2 or 2' per unit time to a predefined or predefinable value
as a function of the detected number of units of washware
which are fed to the conveyor dishwashers 2, 2' per unit
time.
As an alternative or in addition to this, it is preferred
when the control device 50 is designed to automatically
select a predefined or predefinable program sequence in the
drying zone 40, 40' of at least one of the conveyor
dishwashers 2, 2' and set the process parameters associated
with the selected program sequence as a function of the
detected number of units of washware which are fed to the
conveyor dishwashers 2, 2' per unit time. It is feasible
here, in particular, for the control device 50 to be designed
to automatically select a predefined or predefinable
temperature value of an air stream used in the drying zone
40, 40' of at least one of the conveyor dishwashers 2, 2' to
dry the washware and set the temperature of the air stream
used for drying purposes to the selected value as a function
of the detected number of units of washware which are fed to
the conveyor dishwashers 2, 2' per unit time.
As an alternative or in addition to this, it is also feasible
for the control device 50 to be designed to automatically
select a predefined or predefinable value of a volumetric
quantity of a drying-air stream circulating in the drying
zone 40, 40' of at least one of the conveyor dishwashers 2,
2' for drying the washware per unit time and set the
volumetric quantity circulating per unit time to the selected
value as a function of the detected number of units of
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washware which are fed to the conveyor dishwashers 2, 2' per
unit time.
In the conveyor dishwasher (second conveyor dishwasher 2')
illustrated in Fig. 2, it is feasible, in particular, for the
control device 50 to be designed to automatically switch on
or switch off the supply of wash liquid to the pre-wash
nozzles 30 of the pre-wash zone 12 or 12' as a function of
the detected number of units of washware which are fed to the
conveyor dishwashers 2, 2' per unit time; and/or to
automatically switch on or switch off the supply of wash
liquid to the main-wash nozzles 28 of the main-wash zone(s)
14a, 14b or 14' as a function of the detected number of units
of washware which are fed to the conveyor dishwashers 2, 2'
per unit time.
The control apparatus 50 is connected to the washware
detector apparatus 51 via a suitable communications
connection in order to check the type of washware which is
fed to the conveyor dishwasher 2 and detected by the washware
detector apparatus 51 continuously or at prespecified times
or events.
The dishwashing system 100 according to the invention is
therefore also suitable for carrying out a method for washing
washware, with the following method steps being executed:
a) the number of units of washware which are fed to the
conveyor dishwasher(s) 2, 2' with the aid of the
conveyor system 101 per unit time is detected with
the aid of the washware detector apparatus 51 in the
prespecified or prespecifiable region of the conveyor
system 101; and
b) a predefined or predefinable treatment program is
automatically selected and the process parameters
associated with the selected treatment program are
set in the conveyor dishwasher 2, 2' as a function of
the detected number of units of washware which are
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fed to the conveyor dishwasher(s) 2, 2' per unit
time.
The process parameters of a first treatment program are
preferably automatically set here up to a predefined or
predefinable number of units of washware which are fed with
the aid of the conveyor system 101 per unit time in the
conveyor dishwasher 2 or 2', with the process parameters of a
second treatment program being automatically set when the
predefined or predefinable number of units of washware which
are fed with the aid of the conveyor system 101 per unit time
in the conveyor dishwasher 2 or 2' is exceeded. The settable
process parameters include at least one of the following
parameters: the transportation speed at which the washware is
transported through the individual treatment zones 12, 14a,
14b, 16, 18 or 12', 14', 16', 18' of the conveyor dishwasher
2 or 2'; the quantity of wash liquid sprayed in the at least
one wash zone 12, 14a, 14b or 12', 14' per unit time; the
quantity of final-rinse liquid sprayed in the at least one
final-rinse zone 18 or 18' per unit time; the temperature
value of an air stream used to dry the washware in the drying
zone 40 or 40'; and/or the volumetric quantity of a drying-
air stream circulating in the drying zone 40, 40' for drying
the washware per unit time.
In a preferred further development of the method according to
the invention, the transportation speed at which the washware
is transported through the individual treatment zones 12,
14a, 14b, 16, 18 or 12', 14', 16', 18' of the conveyor
dishwasher 2 or 2', the quantity of wash liquid sprayed in
the at least one wash zone 12, 14a, 14b or 12', 14' per unit
time, and the quantity of final-rinse liquid sprayed in the
at least one final-rinse zone 18 or 18' per unit time are in
each case automatically increased when a predefined or
predefinable number of units of washware which are fed with
the aid of the conveyor system 101 per unit time is exceeded
in the conveyor dishwasher 2 or 2'.
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In particular, it is feasible for the temperature of the
drying-air stream to be set to an average value of, for
example, 55 to 65 C at an average transportation speed in the
drying zone 40, 40' of the at least one conveyor dishwasher
2, 2', and/or for the volumetric quantity of drying air
circulating per unit time to be set to an average value of,
for example, 1500 to 2500 m3/h.
The invention is not restricted to the embodiments of Fig. 1
and Fig. 2 shown by way of example in the drawings. Rather,
the invention can be gathered from an overall expert view of
the patent claims and of the description of the exemplary
embodiment.
It is therefore feasible, for example, for only one of the
two conveyor dishwashers 2, 2' to be controlled with the aid
of the control device 50 as a function of the number of units
of washware which are fed by the conveyor system 101 per unit
time.
It is also feasible for the control device 50 to be designed
to selectively automatically select a predefined or
predefinable treatment program for at least one conveyor
dishwasher 2, 2' and set the process parameters associated
with the selected treatment program in the at least one
conveyor dishwasher 2, 2' as a function of the detected
number of units of washware which are fed per unit time.
With regard to the first conveyor dishwasher 2 which has the
first main-wash zone 14a, with main-wash nozzles 28, and the
second main-wash zone 14b, likewise with main-wash nozzles
28, which is connected downstream of the first main-wash zone
14a, it is finally also feasible for the control device 50 to
be designed to automatically switch on or switch off either
the supply of wash liquid to the main-wash nozzles 28 of the
first main-wash zone 14a or the supply of wash liquid to the
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main-wash nozzles 28 of the second main-wash zone 14b as a
function of the detected number of units of washware which
are fed to the at least one conveyor dishwasher 2 per unit
time (e.g., the control device may be set so that wash liquid
supply to only one of the main wash zones 14a and 14b is
switched on or off and the other is not).
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