U.S. patent application number 12/921639 was filed with the patent office on 2011-01-13 for dishwasher and method for cleaning wash ware.
This patent application is currently assigned to PREMARK FEG L.L.C.. Invention is credited to Harry Braun, Harald Disch, Markus Heidt, Klaus Padtberg.
Application Number | 20110005557 12/921639 |
Document ID | / |
Family ID | 40578870 |
Filed Date | 2011-01-13 |
United States Patent
Application |
20110005557 |
Kind Code |
A1 |
Braun; Harry ; et
al. |
January 13, 2011 |
DISHWASHER AND METHOD FOR CLEANING WASH WARE
Abstract
A method, and related dishwasher, for cleaning wash ware that
provides a wash phase followed by a rinse phase, in which rinse
fluid is conducted into a treatment chamber (2) of the dishwasher
(1). The rinse phase is composed of a fresh-water rinse phase and a
steam rinse phase. During the fresh-water rinse phase, a rinse
liquid is sprayed into the treatment chamber (2). During the steam
rinse phase, steam is generated and conducted into the treatment
chamber (2). A total of 0.5 to 2.0 litres of rinse fluid per unit
area of 500 mm.times.500 mm, which is enclosed by the wall of the
treatment chamber (2) in a top view of the treatment chamber, and
preferably 1.0 to 1.7 litres of rinse liquid per unit area of 500
mm.times.500 mm, which is enclosed by the wall of the treatment
chamber (2) in a top view of the treatment chamber, is sprayed into
the treatment chamber (2) during the fresh-water rinse phase.
Inventors: |
Braun; Harry; (Offenburg,
DE) ; Disch; Harald; (Elzach, DE) ; Heidt;
Markus; (Kehl, DE) ; Padtberg; Klaus;
(Korbach, DE) |
Correspondence
Address: |
THOMPSON HINE LLP;Intellectual Property Group
P.O Box 8801
DAYTON
OH
45401-8801
US
|
Assignee: |
PREMARK FEG L.L.C.
Wilmington
DE
|
Family ID: |
40578870 |
Appl. No.: |
12/921639 |
Filed: |
March 3, 2009 |
PCT Filed: |
March 3, 2009 |
PCT NO: |
PCT/US09/35841 |
371 Date: |
September 9, 2010 |
Current U.S.
Class: |
134/56D ;
134/25.2 |
Current CPC
Class: |
A47L 15/0078 20130101;
A47L 15/0005 20130101; A47L 15/0015 20130101; A47L 2601/02
20130101; A47L 2601/04 20130101; A47L 15/4234 20130101 |
Class at
Publication: |
134/56.D ;
134/25.2 |
International
Class: |
A47L 15/42 20060101
A47L015/42 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 11, 2008 |
DE |
10 2008 013 549.6 |
Claims
1. Method for cleaning wash ware in a program-controlled ware
washer having a treatment chamber (2) for accommodating the wash
ware to be cleaned, wherein the method has the following
program-controlled method steps to be executed successively: a wash
phase, in which wash liquid (6) is sprayed from a tank (4) by means
of a wash pump (8) through a wash line system (10) into the
treatment chamber (2) and can flow back into the tank (4) from the
treatment chamber (2) because of the force of gravity; and a rinse
phase, in which rinse fluid is conducted into the treatment chamber
(2), characterized in that the rinse phase is composed of a
fresh-water rinse phase, in which a rinse liquid is sprayed from a
rinse-liquid supply device (14, 21) by means of a rinse pump (12,
13) through a rinse line system (15) into the treatment chamber (2)
and can flow from the treatment chamber (2) into the tank (4)
because of the force of gravity, and of a steam rinse phase, in
which steam is generated by means of a steam generator (20), which
is connected to a fresh-water feed line (28), and is conducted into
the treatment chamber (2), with a total of 0.5 to 2.0 litres of
rinse liquid per unit area of 500 mm.times.500 mm, which is
enclosed by the wall of the treatment chamber (2) in a top view of
the treatment chamber, being sprayed into the treatment chamber (2)
during the fresh-water rinse phase.
2. Method according to claim 1, characterized in that a total water
quantity of 0.05 to 0.25 litre per unit area of 500 mm.times.500
mm, which is enclosed by the wall of the treatment chamber (2) in a
top view of the treatment chamber, is conducted in steam form
during the steam rinse phase into the treatment chamber (2).
3. Method according to claim 2, characterized in that 1.0 to 1.7
litres of rinse liquid per unit area of 500 mm.times.500 mm, which
is enclosed by the wall of the treatment chamber (2) in the top
view of the treatment chamber is sprayed into the treatment chamber
(2) during the fresh-water rinse phase and water quantity of 0.10
to 0.15 litres per unit area of 500 mm.times.500 mm, which is
enclosed by the wall of the treatment chamber (2) in the top view
of the treatment chamber is conducted in steam form during the
steam rinse phase into the treatment chamber (2).
4. Method according to claim 1, characterized in that the steam
rinse phase takes up a period of time of 5 to 60 seconds.
5. Method according to claim 1, characterized in that the steam
rinse phase begins after the fresh-water rinse phase ends.
6. Method according to claim 1, characterized in that the steam
rinse phase and the fresh-water rinse phase at least partially
overlap chronologically.
7. Method according to claim 1, characterized in that the method
furthermore has a condensation and draining phase which is carried
out following the steam rinse phase and lasts for a defined time,
and in which the steam conducted into the treatment chamber (2)
during the steam rinse phase can at least partially condense, drain
and flow into the tank (4) because of the force of gravity.
8. Method according to claim 1, characterized in that clean fresh
water is used as the rinse liquid during the fresh-water rinse
phase, or in that fresh water and the rinse aid which is metered
into the fresh water are used as the rinse liquid during the
fresh-water rinse phase.
9. Method according to claim 1, characterized in that rinse liquid
which is heated or unheated during the fresh-water rinse phase is
sprayed into the treatment chamber (2).
10. (canceled)
11. Dishwasher (1) in the form of a program-controlled ware washer,
having: a program-control device (50) for executing at least one
cleaning program; a treatment chamber (2) into which wash ware can
be manually inserted and from which said wash ware can be manually
removed; a tank (4) down into which liquid from the treatment
chamber (2) can flow because of the force of gravity; a wash system
(7, 8, 9, 10) with a wash pump (8) and a wash line system (10) for
conveying wash liquid (6) from the tank (4) through wash nozzles
(7, 9) into the treatment chamber (2) during a wash phase; a
fresh-water rinse system (12, 13, 15a, 15b, 33, 34) with at least
one rinse pump (12, 13) and at least one rinse line system (15a,
15b) for conveying rinse liquid from a fresh-water supply device
(14, 21) through rinse nozzles (33, 34) into the treatment chamber
(2) during a fresh-water rinse phase; and a steam rinse system (20,
32) with a steam generator (20), which is connected to a
fresh-water feed line (28), for generating steam and conducting the
steam via a steam line (32) into the treatment chamber (2) during a
steam rinse phase, wherein the program-control device (50) is
designed in such a manner that first the wash phase, then the
fresh-water rinse phase and thereafter the steam rinse phase are
executed, characterized in that the program-control device (50) and
the fresh-water rinse system (12, 13, 15a, 15b, 33, 34) controlled
by it are designed to spray a total of 0.5 to 2.0 litres of rinse
liquid per unit area of 500 mm.times.500 mm, which is enclosed by
the wall of the treatment chamber (2) in a top view of the
treatment chamber, into the treatment chamber (2) during the
fresh-water rinse phase.
12. Dishwasher according to claim 11, characterized in that the
program-control device (50) and the steam rinse system (20, 32)
controlled by it are designed to conduct a total water quantity of
0.05 to 0.25 litre per unit area of 500 mm.times.500 mm, which is
enclosed by the wall of the treatment chamber (2) in a top view of
the treatment chamber, in steam form into the treatment chamber (2)
during the steam rinse phase.
13. Dishwasher according to claim 12, characterized in that 1.0 to
1.7 litres of rinse liquid per unit area of 500 mm.times.500 mm,
which is enclosed by the wall of the treatment chamber (2) in the
top view of the treatment chamber is sprayed into the treatment
chamber (2) during the fresh-water rinse phase and water quantity
of 0.10 to 0.15 litres per unit area of 500 mm.times.500 mm, which
is enclosed by the wall of the treatment chamber (2) in the top
view of the treatment chamber is conducted in steam form during the
steam rinse phase into the treatment chamber (2).
14. Dishwasher according to claim 11, characterized in that the
treatment chamber (2) is designed to accommodate at least one
basket of 500 mm.times.500 mm.
15. Dishwasher according to claim 11, characterized in that the
fresh-water supply device (21) for heating the rinse liquid to be
conveyed into the treatment chamber (2) during the fresh-water
rinse phase has a boiler (21) which is connected to a fresh-water
feed line (28) and the outlet (35) of which is connected to the
intake side of a first rinse pump (12), of which there is at least
one.
16. Dishwasher according to claim 11, characterized in that the
fresh-water supply device (14) has a fresh-water tank (14) which is
connected to a fresh-water line (31) and the outlet (36) of which
is connected to the intake side of a second rinse pump (13), of
which there is at least one.
17. Dishwasher according to claim 11, characterized in that the
steam generator (20) is integrated in the boiler (21); and a steam
outlet (23) of the steam generator (20) is connected to the
treatment chamber (2) via a steam line (32), which is separate from
the rinse line system (15) and the wash line system (10), at a
location (37) which is higher than the tank (4).
18. (canceled)
19. Dishwasher according to claim 11, characterized in that the
program-control device (50) is designed to execute a condensation
and draining phase which follows the steam rinse phase and which
lasts for a defined time during which steam which has condensed in
the treatment chamber (2) can flow down into the tank (4) after the
steam rinse phase, before the end of the program is reached.
20. Dishwasher according to claim 11, characterized in that a
rinse-aid metering device is provided for metering rinse aid into
the fresh water of the rinse liquid.
21. Dishwasher according to claim 11, characterized by a
return-prevention means (16) via which the intake end of the at
least one rinse pump (12, 13) is connected to a fresh-water feed
line (17), with the back flow-prevention means (16) being designed
to prevent liquid from flowing back into the fresh-water feed line
(17) in the direction from the at least one rinse pump (12,
13).
22. Dishwasher according to claim 11, characterized by a
water-softening device (39) for conditioning the fresh water for
the fresh-water rinse system (12, 13, 15a, 15b, 33, 34) and the
fresh water for the steam rinse system (20, 32).
Description
[0001] The invention relates to a dishwasher and to a method for
cleaning wash ware in a dishwasher.
[0002] The invention relates, in particular, to a method for
cleaning wash ware in a dishwasher, in particular a commercial
dishwasher, which is in the form of a program-controlled ware
washer. Furthermore, the invention relates to a dishwasher, in
particular a commercial dishwasher, in the form of a
program-controlled ware washer.
[0003] Programme-controlled ware washers are dishwashers which can
be manually loaded and unloaded. Programme-controlled ware washers
(called box-type ware washers or even batch dishwashers) may be
called hood-type dishwashers or even hood-type ware washers or may
be front loader dishwashers (front loader ware washers). Front
loader dishwashers may be under-counter machines, top-counter
machines or else free-standing front loaders.
[0004] Examples of wash ware include plates, cups, pots, trays,
knives, forks, spoons, glasses and other kitchen utensils.
[0005] WO 2006/037447 A1 discloses a dishwasher in the form of a
program-controlled ware washer, in which the following method steps
are run through successively: a wash phase, in which wash liquid is
sprayed from a tank by means of wash pump through a wash line
system into a treatment chamber and can flow back from the
treatment chamber into the tank because of the force of gravity; a
rinse phase, in which heated fresh water as the rinse liquid is
sprayed from a fresh-water feed line by means of a rinse pump
through a rinse line system into the treatment chamber and can flow
from the treatment chamber into the tank because of the force of
gravity; a steam phase, in which steam is generated from heated
fresh water from a fresh-water feed line by means of a steam
generator and is conducted into the treatment chamber by the rinse
line system. Provision is optionally made for the wash ware to be
dried after the steam phase by air being blown in or to be cooled
by letting water in. A booster can alternatively be used to heat up
the fresh water for the rinsing or for steam generation.
[0006] EP 1 738 677 A2 discloses a domestic dishwasher which is
designed for the following procedure: a wash phase, during which
wash liquid is sprayed by means of a pump from a sump via spray
nozzles into a washing chamber which is designed to accommodate
wash ware. Wash liquid is then pumped away, and the sump is filled
with fresh water which is then conveyed by the same pump as the
wash liquid previously to the same spray nozzles as the wash liquid
previously. The transition from the sump to the pump contains a
heater for heating the wash liquid, with it being possible for the
rinse liquid to be heated or left unheated during the rinse phase.
The rinse phase is followed by a steam phase, in which fresh water
from the sump is evaporated by means of the heater and is conducted
via the said spray nozzles into the treatment chamber. The steam
phase may be followed by a drying phase, in which the heated wash
ware dries.
[0007] Commercial dishwashers require water, detergent, rinse aid
and energy in order to clean wash ware. The consumption of
detergent and rinse aid is proportionally dependant on the water
consumption per wash cycle. This is also true of the heating energy
at a constant water admission temperature.
[0008] A commercial dishwasher usually has two water circuits which
are completely separate from each other. These two water circuits
comprise a circuit which is responsible for washing and through
which used water from the wash tank is conducted, and a fresh-water
circuit which is responsible for rinsing and uses fresh water from
a boiler.
[0009] The main object of the rinse phase is to remove the
wash-liquid residues (lye) which are found on the wash ware. The
rinse liquid (pure fresh water or fresh water mixed with rinse aid)
which is sprayed during the rinse phase flows into the wash tank
and then also serves to regenerate the wash liquid.
[0010] Before new rinse liquid is conducted into the wash tank
during the rinse phase, the same quantity of wash liquid is pumped
out of the wash tank.
[0011] At the basis of conventional dishwashers which are known
from the prior art and are in the form of program-controlled ware
washers is a fresh-water or rinse-liquid consumption of 2.4 to 3.5
litres per wash cycle.
[0012] The object to be achieved by the invention is to provide a
way of reducing the quantity of fresh water and quantity of rinse
liquid required for cleaning wash ware, without the efficiency of
the cleaning of the wash ware being adversely affected.
[0013] The invention achieves this object by means of a method for
cleaning wash ware in a dishwasher, in particular in a commercial
dishwasher, which is in the form of a program-controlled ware
washer and has a treatment chamber for accommodating the wash ware
which is to be cleaned, wherein the method has the following
program-controlled method steps which are to be executed
successively: a wash phase, in which wash liquid is sprayed from a
tank (wash tank) by means of a wash pump through a wash line system
into the treatment chamber and can flow back into the tank from the
treatment chamber because of the force of gravity; and a rinse
phase, in which rinse fluid is conducted into the treatment
chamber.
[0014] The term "rinse fluid" used here is to be understood as
meaning any gaseous or vaporous or liquid substance which is
sprayed into the treatment chamber of the dishwasher during the
rinse phase or is supplied to the treatment chamber of the
dishwasher in some other way, with the aim of removing the
wash-liquid residues (lye) which are to be found on the wash ware
after the wash phase.
[0015] With regard to the method for cleaning wash ware, the
present invention is characterized in that the rinse phase is
composed of a fresh-water rinse phase and a steam rinse phase.
During the fresh-water rinse phase, a rinse liquid is sprayed from
a rinse-liquid supply device by means of a rinse pump through a
rinse line system into the treatment chamber of the dishwasher. The
rinse liquid sprayed into the treatment chamber during the
fresh-water rinse phase can subsequently flow into the wash tank of
the dishwasher because of the force of gravity. A suitable
rinse-liquid supply device, from which the rinse liquid is removed
during the fresh-water rinse phase, is, in particular, a
fresh-water tank, in which fresh water and, if appropriate, rinse
aid which is metered into the fresh water are stored, or a boiler,
in which the rinse liquid (i.e. the fresh water and the rinse aid
which, if appropriate, is metered into the fresh water) can
optionally be heated.
[0016] During the steam rinse phase, rinse liquid (i.e. pure fresh
water or fresh water with rinse aid metered in) is evaporated with
the aid of a steam generator connected to a fresh-water feed line,
and the steam generated in such a manner is conducted into the
treatment chamber of the dishwasher.
[0017] It is provided here, as being particularly essential to the
invention, that a total of 0.5 to 2.0 litres of rinse liquid per
unit area of 500 mm.times.500 mm, which is enclosed by the wall of
the treatment chamber in a top view of the treatment chamber, and
preferably a total of 1.0 to 1.7 litres of rinse liquid per unit
area of 500 mm.times.500 mm, which is enclosed by the wall of the
treatment chamber in a top view of the treatment chamber, are
sprayed into the treatment chamber of the dishwasher during the
fresh-water rinse phase.
[0018] The abovementioned rinse-liquid quantities are each based on
a unit area of 500 mm.times.500 mm, since the accommodating
capacity of a dishwasher in the form of a program-controlled ware
washer is usually described or can be described with the aid of the
unit area size of 500 mm.times.500 mm. This unit area size is
derived from the area of a utensil basket customarily used in a
dishwasher.
[0019] As a rule, the area of a utensil basket used for inserting
the wash ware into the treatment chamber of the dishwasher is 500
mm.times.500 mm. A dishwasher, the treatment chamber of which is
designed for accommodating a single utensil basket, is therefore
approximately 500 mm.times.500 mm in size in a top view of the
treatment chamber. A dishwasher which is designed for
simultaneously accommodating two utensil baskets therefore has a
treatment chamber which has, in a top view of the treatment
chamber, an area which is enclosed by the wall of the treatment
chamber and corresponds to two unit areas of 500 mm.times.500
mm.
[0020] The present invention is based on the finding that the steam
conducted into the treatment chamber during the steam rinse phase
can be used for removing residue wash liquid, in particular lye,
from the surfaces of the wash ware. Accordingly, it is possible for
only some of the wash-liquid residues remaining on the surfaces of
the wash ware after the wash phase to be rinsed off during the
fresh-water rinse phase, by the rinse liquid being sprayed into the
treatment chamber of the dishwasher. The remaining amount of
wash-liquid residues is removed with the aid of the steam conducted
into the treatment chamber of the dishwasher during the steam rinse
phase.
[0021] Owing to the fact that, according to the invention, the
rinse phase is composed, firstly, of a fresh-water rinse phase and,
secondly, of a steam rinse phase, the total water consumption per
cleaning cycle can be reduced, with the energy to be applied per
cleaning cycle and the chemical costs being reduced at the same
time.
[0022] Tests have shown that steam which condenses on the surfaces
of wash ware has extremely good rinsing-off effects. The steam
introduced into the treatment chamber of the dishwasher during the
steam rinse phase is distributed uniformly in the treatment chamber
in accordance with the second fundamental law of thermodynamics,
and therefore said steam which is introduced into the treatment
chamber in particular even reaches wash-ware shadow zones which may
possibly be present, i.e. surfaces of the wash ware which are not
directly reachable by the spray jet. Put another way, this means
that the steam introduced into the treatment chamber of the
dishwasher during the steam rinse phase reaches every surface of
the wash ware within the treatment chamber irrespective of the
position and the orientation of the surface of the wash ware and
can be deposited substantially in equal parts (uniformly) on the
surfaces of the wash ware. This advantageous effect cannot be
achieved in the case of a rinse phase which merely comprises a
fresh-water rinse phase, in which rinse liquid rather than any
steam is sprayed into the treatment chamber.
[0023] Surfaces of wash ware, which, on account of their
geometrical shape, do not permit fluid to flow off from them
because of gravity, i.e. do not permit liquid to flow off from them
because of the force of gravity, provide restrictions with regard
to the use of steam as a rinsing medium. These restrictions may
occur, for example, in the case of wash ware having depressions in
the base, such as, for example, in the case of small bowls or
glasses, if said wash ware is correspondingly positioned in the
treatment chamber of the dishwasher and the orientation of at least
some of the surfaces of the wash ware does not permit liquid to
flow off from them in a gravity-induced manner.
[0024] The restriction discussed above means that a steam rinse
phase alone is, under some circumstances, not sufficient as a rinse
phase to achieve a good cleaning result. For this reason, according
to the present invention, the rinse phase used for rinsing off the
wash-liquid residues remaining on the surfaces of the wash ware
after the wash phase is composed of the steam rinse phase and the
fresh-water rinse phase. It has been shown that only the
combination of a fresh-water rinse phase and a steam rinse phase
supplies a thoroughly satisfactory cleaning result.
[0025] In comparison to a rinse phase carried out in a conventional
dishwasher known from the prior art, with the solution according to
the invention, in which the fresh-water rinse phase is employed in
conjunction with the steam rinse phase, the quantity of fresh water
used in total during the rinse phase can be significantly
reduced.
[0026] In a preferred realization of the method according to the
invention, it is provided that a standard wash phase is followed by
the previously described fresh-water rinse phase carried out with a
reduced quantity of fresh water of 0.5 to 2.0 litres, and
preferably with a reduced quantity of fresh water of 1.0 to 1.7
litres. This fresh-water rinse phase is followed by the steam rinse
phase, in which the wash-liquid residues still remaining on the
surfaces of the wash ware after the fresh-water rinse phase are
completely rinsed off with the aid of the steam introduced into the
treatment chamber of the dishwasher. This steam rinse phase employs
a total quantity of fresh water of 0.05 to 0.25 litre, and
preferably a quantity of fresh water of 0.10 to 0.15 litre in steam
form. The quantities of fresh water stated for this preferred
realization of the solution according to the invention are always
based on a dishwasher in the form of a program-controlled ware
washer, the treatment chamber of which is designed for a utensil
basket of 500 mm.times.500 mm, and therefore a unit area of 500
mm.times.500 mm is enclosed by the wall of the treatment chamber in
a top view of the treatment chamber.
[0027] In the abovementioned, preferred realization of the solution
according to the invention, the steam rinse phase lasts for a total
of approximately 5 to 60 seconds, and preferably for a total of
approximately 10 to 30 seconds.
[0028] Following the steam rinse phase, a condensation and draining
phase is then carried out, which phase lasts for a defined time,
and in which the steam conducted into the treatment chamber of the
dishwasher during the steam rinse phase can at least partially
condense on the surfaces of the wash ware, can drain and flow into
the wash tank because of the force of gravity. The abovementioned
condensation and draining phase preferably lasts for approximately
10 to 60 seconds, and even more preferably approximately 20 to 30
seconds.
[0029] In comparison to the currently customary cleaning methods
used in dishwashers--in the case of the abovementioned preferred
realization of the method according to the invention, approx. 1
litre of fresh water and a corresponding quantity of detergent and
rinse aid and approx. 50 to 200 kJ of energy can be saved per wash
or rinsing cycle.
[0030] The object on which the invention is based is achieved with
regard to the apparatus by means of a dishwasher, in particular by
means of a commercial dishwasher, in the form of a
program-controlled ware washer which is designed for executing the
above-described method according to the invention. In this case,
the dishwasher has a program-control device for executing at least
one cleaning program; a treatment chamber into which wash ware can
be manually inserted and from which said wash ware can be removed;
a tank (wash tank) down into which liquid from the treatment
chamber can flow because of the force of gravity; a wash system
with a wash pump and a wash line system for conveying wash liquid
from the wash tank through wash nozzles into the treatment chamber
during a wash phase; a fresh-water rinse system with at least one
rinse pump and at least one rinse line system for conveying rinse
liquid from a fresh-water supply device through rinse nozzles into
the treatment chamber during a fresh-water rinse phase; and a steam
rinse system with a steam generator, which is connected to a
fresh-water feed line, for generating steam and for conducting the
steam via a steam line into the treatment chamber during a steam
rinse phase. In this case, the program-control device is designed
in such a manner that first the wash phase, then the fresh-water
rinse phase and thereafter the steam rinse phase are executed.
[0031] The dishwasher according to the invention is distinguished
in that the program-control device and the fresh-water rinse system
controlled by it are designed to spray a total of 0.5 to 2.0 litres
of rinse liquid per unit area of 500 mm.times.500 mm, which is
enclosed by the wall of the treatment chamber in a top view of the
treatment chamber, and preferably a total of 1.0 to 1.7 litres of
rinse liquid per unit area of 500 mm.times.500 mm, which is
enclosed by the wall of the treatment chamber in a top view of the
treatment chamber, during the fresh-water rinse phase.
[0032] The invention is described below using preferred embodiments
of the dishwasher according to the invention with reference to the
attached drawings, in which
[0033] FIG. 1 schematically shows a dishwasher, in particular a
commercial dishwasher, in the form of a program-controlled ware
washer, according to a first embodiment; and
[0034] FIG. 2 schematically shows a dishwasher, in particular a
commercial dishwasher, in the form of a program-controlled ware
washer, according to a second embodiment.
[0035] The dishwasher 1 according to the invention contains a
treatment chamber 2 for cleaning wash ware (not illustrated). A
wash tank 4 in which liquid can flow back out of the cleaning
chamber 2 because of the force of gravity is arranged under the
treatment chamber 2. The wash tank 4 can be covered at the
transition to the treatment chamber 2 with the aid of a strainer
(not illustrated). The wash tank 4 contains wash liquid 6, which is
usually water, to which detergent can optionally be automatically
supplied by a detergent-metering apparatus (not illustrated). The
wash liquid 6 can be conveyed by a wash pump 8 via a wash line
system 10 to wash nozzles 7 and 9 and can be sprayed through said
wash nozzles 7, 9 in the treatment chamber 2 onto the wash ware to
be cleaned. The sprayed wash liquid 6 subsequently flows back into
the wash tank 4. A discharge line 3 with a discharge pump 11 can be
connected to the lower end 5 of the wash tank for the purpose of
emptying the wash tank 4, if the need arises.
[0036] In the embodiment, illustrated in FIG. 1, of the dishwasher
1 according to the invention, the intake side of a first rinse pump
12 is connected to an outlet 35 of a boiler 21. The boiler 21
furthermore has an inlet 22 which is connected to a fresh-water
feed line 28 and via which either fresh water or fresh water with
rinse aid metered into it is supplied to the boiler 21. In the
boiler 21, the liquid (pure fresh water or fresh water with rinse
aid metered into it) which is supplied via the inlet 22 is heated
up in accordance with the stipulations of a process sequence. Via
the first rinse pump 12, the intake side of which is connected to
the boiler outlet 35, the rinse liquid which is heated up in the
boiler 21 can be supplied, for example during a fresh-water rinse
phase, via a rinse line system 15, 15a to rinse nozzles 33 and 34,
respectively. The rinse nozzles 33 and 34 are arranged in the
treatment chamber 2 in order to spray the rinse liquid heated in
the boiler 21 onto the wash ware in the treatment chamber 2. Of
course, however, it is also conceivable for the boiler 21 to be
supplied via the inlet 22 and the fresh-water feed line 28 with
pure fresh water into which a rinse aid is metered after the fresh
water has been heated in the boiler 21.
[0037] Furthermore, in the embodiment, illustrated in FIG. 1, of
the dishwasher 1 according to the invention, a second rinse pump 13
is provided, the intake side of which is connected to a fresh-water
tank 14 and the delivery side of which is connected to a rinse line
system 15, 15b. The rinse line system 15b which extends from the
delivery side of the second rinse pump 13, and the rinse line
system 15a which extends from the delivery side of the first rinse
pump 12 merge into a common rinse line system 15. By means of the
second rinse pump 13 which is connected to the fresh water tank 14,
unheated rinse liquid can be conveyed to the rinse nozzles 33 and
34 arranged in the treatment chamber 2 in order to spray unheated
rinse liquid onto the wash ware, if the need arises.
[0038] The fresh-water tank 14 has an inlet 37 which is connected
to a fresh-water feed line 31. Either pure fresh water or fresh
water with rinse aid metered into it is supplied via this
fresh-water feed line 31 to the fresh-water tank 14. Of course,
however, it is also conceivable to arrange, downstream of the
outlet 36 of the fresh-water tank 14, a metering device, not
illustrated in FIG. 1, for the metering in of rinse aid.
[0039] The wash nozzles 7, 9 and the rinse nozzles 33, 34 are
respectively preferably arranged above and below the wash ware
region and directed towards the wash ware region of the treatment
chamber 2. In the embodiment, illustrated in FIG. 1, of the
dishwasher 1 according to the invention, an upper wash-nozzle
system and an upper rinse-nozzle system formed separately
therefrom, and a lower wash-nozzle system and a lower rinse-nozzle
system formed separately therefrom are provided. Of course,
however, it would also be conceivable to provide an upper and a
lower wash-nozzle system which together serve to spray wash liquid
and to spray rinse liquid. Instead of being arranged at the bottom
and top, the wash nozzles 7, 9 and/or the rinse nozzles 33, 34 may
also be arranged only at the top or only at the bottom, or instead
or in addition, also on one side of the treatment chamber 2 and
directed into the wash ware region transversely with respect to the
treatment chamber 2.
[0040] In the embodiment, illustrated in FIG. 1, of the dishwasher
1 according to the invention, both the boiler 21 and the
fresh-water tank 14 are connected via fresh-water feed lines 24,
26, 28, 29 and 31 to a return-prevention means 16. The
return-prevention means 16 serves to prevent fresh water from being
able to sucked back into a fresh-water feed line 17 from the intake
side of the first rinse pump 12 and/or from the intake side of the
second rinse pump 13.
[0041] The return-prevention means 16 has an outlet 40 which is
connected via fresh-water feed lines 24 and 41 to a water-softening
device 39. The water-softening device 39 has, firstly, a salt
container 42 which is connected to the fresh-water feed line 41
and, secondly, first and second water softeners 39a, 39b which are
arranged parallel to each other. The two water softeners 39a, 39b
which are arranged parallel to each other are connected via a
corresponding fresh-water line system and the fresh-water feed line
24 to the outlet 40 of the return-prevention means 16. The water
softeners 39a, 39b of the water-softening device 39 can be operated
alternately by suitable activation of the valves 43, in order to
soften the fresh water supplied to the boiler 21 via the
fresh-water feed lines 26 and 28 and to soften the fresh water
supplied to the fresh-water tank 14 via the fresh-water feed lines
26, 29 and 31.
[0042] The salt container 42 belonging to the water-softening
device 39 contains a suitable salt or a suitable chemical with
which, when the need arises, a water-softening agent metered in via
the water softeners 39a and 39b or a decomposition product produced
when a water-softening agent is metered in can be suitably
regenerated. The salt container 42 can be topped up with the salt
or the chemical from the treatment chamber 2 of the dishwasher 1
via an opening which can be closed by a cover 44.
[0043] In the illustrated and preferred embodiment of the
dishwasher 1 according to the invention, the boiler 21 has an
integrated steam generator 20. A corresponding steam outlet 23 of
the steam generator 20 is formed on the upper region of the boiler
21. The steam outlet 23 of the steam generator 20 is connected via
a steam line 32 to the treatment chamber 2 at a location 37 above
the wash tank 4 in order, when the need arises, to conduct the
steam generated in the steam generator 20 into said treatment
chamber. The outlet opening of the steam line 32 is preferably
located between the upper nozzles 7, 33 and the lower nozzles 9, 34
of the wash line system 10 and of the rinse line system 15. Of
course, however, other positions are also possible.
[0044] The boiler 21, which serves not only to heat the rinse
liquid but also to generate steam, contains a heater 45.
Furthermore, a level sensor 46 which controls, for example, a valve
19 of the fresh-water line 17 may be arranged in or on the
boiler.
[0045] In the preferred embodiment, illustrated in FIG. 1, of the
dishwasher 1 according to the invention, it is optionally possible,
by means of the provision of the fresh-water tank 14 and the second
rinse pump 13, also to supply non-heated rinse liquid via the rinse
line system 15b and 15 to the rinse nozzles 33 and 34,
respectively. Accordingly, it is possible, by means of suitable
activation, for example of the rinse pumps 12, 13, and/or by means
of suitable activation, for example of the valves 19, 27 and 30
arranged in the fresh-water feed lines to the fresh-water tank 14
and the boiler 21, to supply non-heated or heated rinse liquid to
the treatment chamber 2.
[0046] A program-control device 50 for controlling at least one
cleaning program is designed in such a manner and is connected to
the controllable components of the dishwasher, for example to the
valves 19, 27 and 30, to the wash pump 8, to the first rinse pump
12, to the second rinse pump 13, and/or to a heater control circuit
for controlling the heater 45, in order to realize a cleaning
method (cleaning cycle) with the following steps (phases) to be
executed successively: [0047] 1. A wash phase, in which wash liquid
is sprayed from the wash tank 4 by means of the wash pump 8 through
the wash line system 10 into the treatment chamber 2 and can then
flow back into the wash tank 4 from the treatment chamber 2 because
of the force of gravity; [0048] 2. A fresh-water rinse phase, in
which heated or unheated fresh water or fresh water with rinse aid
metered into it, as the rinse liquid, is sprayed by means of the
first rinse pump 12 and the second rinse pump 13 into the treatment
chamber 2 and can then flow into the wash tank 4 from the treatment
chamber 2 because of the force of gravity; and [0049] 3. A steam
rinse phase, which follows the fresh-water rinse phase and in which
steam generated by the steam generator 20 is introduced into the
treatment chamber 2 via the steam line 32, which is formed
separately from the wash line system 10 and separately from the
rinse line system 15.
[0050] Furthermore, the program controller 50 is preferably
designed in such a manner that a condensation and draining phase is
executed for a specific period of time in a program-controlled
manner following the steam rinse phase, during which period of time
steam introduced into the treatment chamber 2 during the steam
rinse phase can condense and can drain from the treatment chamber 2
into the wash tank 4, before the end of the program is reached.
[0051] FIG. 2 schematically provides a dishwasher, in particular a
commercial dishwasher, in the form of a program-controlled ware
washer according to the second preferred embodiment of the solution
according to the invention. In contrast to the first embodiment
illustrated in FIG. 1, the dishwasher 1 illustrated in FIG. 2 does
not have a fresh-water tank and therefore also does not have a
second rinse pump via which--as illustrated in FIG. 1--unheated
rinse liquid can be supplied via a rinse line system to the rinse
nozzle. Otherwise, the dishwasher 1 illustrated in FIG. 2 is
identical in a structural and functional regard with the dishwasher
described previously with reference to FIG. 1.
[0052] Of course, it is conceivable that the heater control circuit
(not illustrated explicitly) can correspondingly activate the
heater 45 of the boiler 21 or of the steam generator 20 in order to
provide rinse liquid which is heated to a greater or lesser
extent.
[0053] The invention is not restricted to the embodiments of the
dishwasher 1 that are shown by way of example in the drawings. On
the contrary, the invention arises from an expert overall
consideration of the patent claims and the description of the
exemplary embodiments.
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