U.S. patent application number 13/527721 was filed with the patent office on 2012-10-18 for method for the wet-treatment of items of laundry.
This patent application is currently assigned to Herbert Kannegiesser GmbH. Invention is credited to Wilhelm Bringewatt, Engelbert Heinz.
Application Number | 20120260434 13/527721 |
Document ID | / |
Family ID | 39712660 |
Filed Date | 2012-10-18 |
United States Patent
Application |
20120260434 |
Kind Code |
A1 |
Bringewatt; Wilhelm ; et
al. |
October 18, 2012 |
METHOD FOR THE WET-TREATMENT OF ITEMS OF LAUNDRY
Abstract
The invention makes provision for the final wash liquid from the
washing device to be separated from the items of laundry in a
water-removal device, specifically together with a large portion of
the final wash liquid bound in the items of laundry. The items of
laundry are then rinsed in the water-removal device. Following
this, the rinse liquid is routed away from the items of laundry.
The final wash liquid and the rinse liquid are temporarily stored
in separate storage tanks and returned to the subsequent wash
process in a deliberate manner. A mixture of at least a portion of
the final wash liquid and the rinse liquid is fed particularly to
the prewash zone in order to prewash the next batch of items of
laundry.
Inventors: |
Bringewatt; Wilhelm; (Porta
Westfalica, DE) ; Heinz; Engelbert; (Vlotho,
DE) |
Assignee: |
Herbert Kannegiesser GmbH
Vlotho
DE
|
Family ID: |
39712660 |
Appl. No.: |
13/527721 |
Filed: |
June 20, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12123523 |
May 20, 2008 |
8225445 |
|
|
13527721 |
|
|
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Current U.S.
Class: |
8/137 |
Current CPC
Class: |
D06F 31/005 20130101;
D06F 35/006 20130101 |
Class at
Publication: |
8/137 |
International
Class: |
D06L 1/16 20060101
D06L001/16 |
Foreign Application Data
Date |
Code |
Application Number |
May 21, 2007 |
DE |
102007023801.2 |
Claims
1. A method for the wet-treatment of items of laundry, with the
items of laundry being washed in a washing device and having water
removed from them and being rinsed in at least one downstream
water-removal device, wherein a mixture of final wash liquid, which
is removed from the items of laundry by the at least one
water-removal device, and rinse liquid is returned to the washing
device.
2. The method according to claim 1, wherein the mixture of final
wash liquid, which is removed from the items of laundry in the
water-removal device, and rinse liquid is used to prewash a next
batch of items of laundry.
3. The method according to claim 1, wherein all the final wash
liquid, which is removed from the items of laundry in the region of
the water-removal device, and rinse liquid are returned to a final
wash zone (17) and to a prewash zone (16) of the washing
device.
4. The method according to claim 3, wherein at least a portion of
the temporarily stored final wash liquid and the rinse liquid,
which is separately temporarily stored, is returned to the prewash
zone (16) of the washing device.
5. The method according to claim 3, wherein a portion of the final
wash liquid which is removed from the items of laundry in the
water-removal device is returned to the final wash zone (17).
6. The method according to claim 5, wherein such a portion of the
final wash liquid which is removed from the items of laundry in the
water-removal device and has not been fed to the prewash zone (16)
is returned to the final wash zone (17).
7. The method according to claim 1, wherein fresh water is fed only
to the water-removal device.
8. The method according to claim 7, wherein fresh water is fed to
the water-removal device only before rinsing of the items of
laundry in the water-removal device, after the free liquor in the
final wash liquid and a large portion of the bound liquor in the
final wash liquid have been removed from the items of laundry in
the water-removal device.
Description
STATEMENT OF RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 12/123,523 having a filing date of 20 May 2008, which is
based on and claims convention priority under 35 USC 119 on German
Patent Application No. 10 2007 023 801.2 having a filing date of 21
May 2007 and which is incorporated herein by this reference in its
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The invention relates to a method for the wet treatment of
items of laundry, with the items of laundry being washed in a
washing device and having water removed from them and being rinsed
in at least one downstream water-removal device.
[0004] 2. Prior Art
[0005] Laundry is subjected to wet-treatment in several stages,
specifically by washing, rinsing and water-removal. Washing is
performed by a prewash operation and a subsequent final wash
operation. The treatment liquid is replaced between at least some
treatment stages. Fresh water is used for rinsing purposes, at
least for the most part.
[0006] It is customary to reuse the treatment liquid which is
produced at least after some treatment stages. In many cases, a
sufficient quantity of the treatment liquid to be reused is not
available at the correct time. It is then necessary to feed in more
fresh water as required. This produces unnecessary costs.
BRIEF SUMMARY OF THE INVENTION
[0007] Taking the above as a starting point, the invention is based
on the object of providing a method for the wet-treatment of
laundry, which method operates more economically than conventional
methods.
[0008] A method for achieving this object is a method for the
wet-treatment of items of laundry, with the items of laundry being
washed in a washing device and having water removed from them and
being rinsed in at least one downstream water-removal device,
characterized in that the items of laundry are separated from at
least a large portion of the bound liquor before being rinsed by
the water-removal device. On account of at least a large portion of
the treatment liquid bound in the items of laundry, specifically
so-called bound liquor, being removed before the items of laundry
are rinsed in the at least one water-removal device, there is only
a small residual quantity of bound liquor in the items of laundry.
The bound liquor is preferably final wash liquid. As a result, the
residual quantity of final wash liquid bound in the items of
laundry is minimized. Therefore, a large portion of separated bound
liquor is available for reuse in the wash process. The quantity of
fresh water required is reduced as a result. Since the items of
laundry contain only a minimal amount of bound treatment liquid
before rinsing, only very little treatment liquid from the final
wash operation (final wash liquid) has to be rinsed out from the
items of laundry. This also reduces the quantity of fresh water
required for rinsing purposes.
[0009] Provision is also made for the free liquor to likewise be
separated from the items of laundry in the water-removal device,
before a large portion of the bound liquor is removed from the
items of laundry in the at least one water-removal device.
Therefore, almost all the final wash liquid, to be precise both the
final wash liquid which is bound in the items of laundry and
unbound final wash liquid, is separated from the items of laundry
before rinsing. This large portion of final wash liquid is again
available for washing a subsequent batch laundry before the
beginning of the rinse process and only a small residual quantity
of final wash liquid has to be rinsed out of the laundry in the
rinse process.
[0010] According to a preferred development of the method,
provision is made for the free liquor, which is removed from the
items of laundry by the at least one water-removal device or in the
water-removal device, and a large portion of the bound liquor to be
temporarily stored. This temporary storage leads to a sufficiently
large supply of reusable treatment liquid always being available
and the treatment liquid not having to be returned to the washing
device immediately after being removed from the washed laundry.
[0011] According to a particularly advantageous refinement of the
method according to the invention, provision is made for the rinse
liquid which is produced in the region of the water-removal device
to also be temporarily stored. The rinse liquid is preferably
stored separately from the liquid removed from the wash process, in
particular final wash liquid, which is removed from the items of
laundry before rinsing. Since the final wash liquid is usually at a
higher temperature than the rinse liquid which is relatively cold,
relatively warm final wash liquid and relatively cold rinse liquid
are available in the different storage containers. In addition, the
rinse liquid is less contaminated than the final wash liquid
because a relatively small fraction of residual final wash liquid
is rinsed out of the items of laundry using the rinse liquid and
fresh water is used as rinse liquid, so that the residual quantity
of final wash liquid present in the rinse liquid is relatively
highly diluted. The separate temporary storage of the rinse liquid
on the one hand and the final wash liquid on the other hand permits
the final wash liquid to be used partly at any time in a different
location to the rinse liquid. However, it is primarily possible to
mix the rinse liquid and the separately temporarily stored final
wash liquid as desired, to be precise particularly in such a way
that the mixture comprising a corresponding quantity of rinse
liquid and final wash liquid is at a temperature which is suitable
for the intended reuse of the mixture comprising final wash liquid
and rinse liquid.
[0012] Provision is made for a portion of the temporarily stored
final rinse liquid, and also only this, to be returned to the final
wash zone of the washing device. The final wash liquid is
preferably fed to the start of the final wash zone. Since the final
wash liquid is at a higher temperature than the rinse liquid and
the final wash operation is carried out with the treatment liquid
at a higher temperature than during the prewash operation, the
temporarily stored final wash liquid is particularly suitable for
reuse in the final wash zone. The final wash liquid which has a
relatively high temperature therefore does not need to be reheated
or may need to be reheated only slightly, in order to be reused in
the final wash zone.
[0013] The quantity of temporarily stored final wash liquid which
is returned to the final wash zone corresponds approximately to the
quantity of final wash liquid removed from the items of laundry
before the final wash operation. In this way, the final wash liquid
removed before the final wash operation is again replaced by
reusable final wash liquid from the preceding wash process.
[0014] A further method for achieving the object cited in the
introduction is a method for the wet-treatment of items of laundry,
with the items of laundry being washed in a washing device and
having water removed from them and being rinsed in at least one
downstream water-removal device, characterized in that a mixture of
final wash liquid, which is removed from the items of laundry by
the at least one water-removal device, and rinse liquid is returned
to the washing device. In this case, said method may be a preferred
development of the above-described method. According to this
method, which may represent an independent invention, as per
characterized in that a portion of the temporarily stored final
wash liquid is returned to the final wash zone of the washing
device, provision is made for the final wash liquid which is
produced in the water-removal device and rinse liquid to be at
least partially mixed. Provision is preferably made for final wash
liquid on the one hand and rinse liquid on the other hand, which
liquids are stored in different storage containers, to be mixed in
accordance with requirements, to be precise particularly with
regard to the required quantity and/or temperature. In this case,
the bound liquor of which a large portion is removed from the items
of laundry in the water-removal device before rinsing, that is to
say final wash liquid, is also admixed.
[0015] Provision is also made for all the final wash liquid which
is removed from the laundry in the region of the water-removal
device before rinsing, in particular the major portion of bound
final wash liquid, to be returned partly to the prewash zone and
partly to the final wash zone of the washing device. Only
relatively warm final wash liquid, including the major portion of
bound final wash liquid which is removed from the items of laundry
in the water-removal device, that is to say no rinse liquid, is
preferably fed to the final wash zone. This separation of rinse
liquid and final wash liquid is possible on account of the separate
storage of the final wash liquid and the rinse liquid. In contrast,
a mixture of separately temporarily stored rinse liquid and a
portion of the final wash liquid which is not required in the final
wash zone, including the bound final wash liquid from the preceding
wash process, is returned to the prewash zone. By mixing final wash
liquid and rinse liquid, the liquid mixture is provided with a
temperature which is lower than the temperature of the final wash
liquid, so that the temperature of the mixture, which is fed to the
prewash zone, comprising final wash liquid and rinse liquid from
the preceding batch of laundry is relatively low, specifically does
not exceed the maximum permissible temperature. In particular, a
temperature which does not lead to protein flecks in the items of
laundry can be set by mixing the different treatment liquids from
the final wash zone and the rinse process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Preferred exemplary embodiments of the invention are
explained in greater detail below with reference to the drawing, in
which:
[0017] FIG. 1 shows a side view of an apparatus for carrying out
the methods according to the invention.
[0018] FIG. 2 shows a schematic side view of the apparatus for
carrying out the method with consumption of treatment liquid and
fresh water using the example of cotton.
[0019] FIG. 3 shows a view which is analogous to FIG. 2, using the
example of terry toweling.
[0020] FIG. 4 shows an illustration which is analogous to FIG. 2,
using the example of workwear.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0021] The apparatus shown here represents an example of an inline
washing system for the wet-treatment of items of laundry as per the
methods according to the invention. The items of laundry may be any
type of laundry, for example bed linen, table linen, items of
clothing, items of workwear, floor mats or the like. The items of
laundry are washed, rinsed and have water removed from them in the
apparatus. The apparatus has a pass-through washing machine 10 and
at least one downstream water-removal device. The water-removal
device is a spin dryer 11 or laundry centrifuge, it also being
possible for the water-removal device to be formed from a plurality
of spin dryers 11 or laundry centrifuges. However, as an
alternative, the water-removal device can also be formed by at
least one water-removal press.
[0022] The pass-through washing machine 10 has a drum 12 which can
be driven in rotation about a preferably horizontal axis of
rotation. In the drum 12, a plurality of chambers 15 which follow
one another in the passage direction 14 of the items of laundry
(not shown) through the drum 12 are formed by transverse partition
walls 13. The chambers 15 may be of the same size but may also be
of different sizes. The pass-through washing machine 10 shown here
has four successive chambers 15, a first chamber 15 forming the
prewash zone, while the three following chambers 15 form a final
wash zone 17. The pass-through washing machine 10 does not have a
rinse chamber. In the apparatus shown here, the items of laundry
are rinsed in the at least one spin dryer 11 (laundry centrifuge),
which is arranged downstream of the pass-through washing machine
10, or alternatively in the at least one water-removal press.
[0023] The pass-through washing machine 10 permits bath exchange in
the first chamber 15 of the final wash zone 17, for which reason
the chamber 15 which is second as seen in the passage direction 14
has an associated outer drum 18 which is used to discharge prewash
liquid. The prewash liquid may also be discharged at the end of the
prewash zone 16, that is to say in the chamber 15 for forming the
prewash zone 16. In this case, the said (first) chamber 15 has an
associated outer drum 18. It is also feasible for one or each
further chamber 15 of the final wash zone 17 to have an associated
outer drum, in particular when the pass-through washing machine 10
operates in accordance with the countercurrent principle.
[0024] The spin dryer 11 has a collection tank 19 which can be
formed, for example, from the base of the spin dryer 11. Two
separate storage tanks 20, 21 are also provided. Each storage tank
20, 21 is connected to the collection tank 19 of the spin dryer 11
via a supply line 22. The supply line 22 can be shut off by a
dedicated valve 23 upstream of each storage tank 20, 21.
[0025] An outflow line 24 leads from the storage tank 20 to the
first chamber 15 of the pass-through washing machine 10, that is to
say to the single chamber 15 of the prewash zone 16. In the
exemplary embodiment shown, the outflow line 24 leads to a feed
funnel 26 of the pass-through washing machine 10. The items of
laundry to be washed pass from the feed funnel 26 to the first
chamber 15 which forms the prewash zone 16. A second outflow line
27 leads from the storage tank 20 to the first chamber 15 of the
final wash zone 17, that is to say to the second chamber 15 of the
pass-through washing machine 10 shown here.
[0026] Only one outflow line 28 leads from the second storage tank
21 to the supply funnel 26 upstream of the first chamber 15 of the
prewash zone 16. The outflow lines 24, 27 and 28 each have an
associated valve 29.
[0027] Various exemplary embodiments of the method according to the
invention are explained in greater detail below with reference to
FIGS. 2 to 4:
[0028] According to the invention, provision is made for not only
the free final wash liquor but also at least a large portion of the
bound final wash liquor to be separated from the items of laundry
by the at least one spin dryer 11 or another water-removal device,
for example a water-removal press, before rinsing. A large portion
of the bound final wash liquor which is removed from the items of
laundry before rinsing means that the items of laundry are
separated from such a large portion of the free liquor, which is
also removed from the items of laundry by the least one spin dryer
11 or a laundry press after rinsing, before said items of laundry
are dried in the dryer. The items of laundry are therefore
"dryer-dry" when, as per the method according to the invention, a
large portion of the bound liquor, that is to say a large portion
of the bound final wash liquid, has been removed from the items of
laundry by the least one spin dryer 11 or another water-removal
device before rinsing.
[0029] The treatment liquid which is separated from the items of
laundry by the least one spin dryer 11 or another water-removal
device, to be precise both final wash liquor and also the rinse
liquor, including a large portion of the bound final wash liquor or
rinse liquor, which is produced during rinsing is separately
temporarily stored in the storage tanks 20, 21. The storage tank 20
is provided for the final wash liquid, including a large portion of
the bound liquor, which is removed from the items of laundry by the
respective water-removal device before rinsing. The rinse liquid,
including the bound liquor, is separately temporarily stored in the
second storage tank 21. The final wash liquid, to be precise the
free liquor and a large portion of the bound liquor, is fed from
the storage tank 20 partly to the final wash operation, to be
precise into the first chamber 15 of the final wash zone 17, and
partly is conducted to the prewash zone 16, preferably into the
feed funnel 26 in order to wash items of laundry to be washed into
the pass-through washing machine 10. The rinse liquor, that is to
say all the free rinse liquid and a large portion of the bound
rinse liquid, from the at least one spin dryer 11 or another
water-removal device, for example a water-removal press, is used
only to wash in washed items of laundry, that is to say is fed to
the prewash zone 16, to be precise, in accordance with the
invention, with the remaining portion of the final wash liquid
which is also separated from the items of laundry by the at least
one water-removal device.
[0030] FIG. 2 shows the consumption of treatment liquid, including
fresh water, using the example of items of cotton laundry. In this
case, 4.9 kg of treatment liquid, namely prewash liquid, is used
per kilogram of laundry for the prewash operation. The prewash
liquid is formed from a mixture of the rinse liquid originating
from the at least one spin dryer 11 and final wash liquid from the
storage tanks 20 and 21. In concrete terms, all the rinse liquid,
specifically 3.1 l per kilogram of laundry, and a portion of the
final wash liquid, specifically 1.8 l per kilogram of laundry, is
mixed to form the prewash liquid.
[0031] After the prewash operation in the first chamber 15, 2.4 l
of free prewash liquid per kilogram of laundry is discharged in the
second chamber 15, which is the first chamber 15 of the final wash
zone 17, via the outer drum 18. For final washing purposes, 2 l of
final wash liquid per kilogram of laundry is filled, to be precise
of the final wash liquor temporarily stored in the storage tank 20,
with which the preceding batch of laundry has been treated. This
final wash liquor, that is to say free final wash liquor and a
large portion of the bound final wash liquor from the water-removal
device, is also approximately at the temperature which is required
for final washing purposes, specifically is warmer than the
temperature of the treatment liquid in the prewash zone 16. As a
result of 2.4 l of treatment liquid being discharged from the
prewashed laundry and only 2 l of final wash liquid per kilogram of
laundry being fed in, the final wash operation with 4.5 kg of final
wash liquor per kilogram of laundry takes place in the final wash
zone 17.
[0032] After final washing, the items of laundry leave the
pass-through washing machine 10 via a discharge chute 30 which is
at the rear as seen in the passage direction 14. From said
discharge chute, the laundry together with all the final wash
liquor enters the at least one spin dryer 11 or another
water-removal device. The free final wash liquor immediately drains
into the centrifuge and is collected in the collection tank 19 of
the spin dryer 11. The items of laundry are now spun in the spin
dryer 11 and in the process freed from a large portion of the
liquor which is bound in the items of laundry, specifically the
bound final wash liquor. The items of laundry then contain only a
residual amount of moisture which corresponds almost to that which
remains in the items of laundry after these have left the spin
dryer 11 in order to be dried in a downstream dryer, preferably
around approximately 0.1 l per kilogram of laundry. In the example
of cotton, only approximately 0.7 kg of final wash liquor per
kilogram of laundry is contained in the items of laundry after
removal of the large portion of the bound final wash liquor. As a
result, 3.8 l of final wash liquor per kilogram of laundry, to be
precise free liquor and a large portion of the bound liquor, all of
which final wash liquor is then conducted into the storage tank 20,
have collected in the collection tank 19.
[0033] For subsequent rinsing of the items of laundry in the at
least one spin dryer 11 or another laundry-treatment device, the
spin dryer 11 is now fed with 3 l of fresh water per kilogram of
laundry. Therefore, the items of laundry are rinsed in the spin
dryer 11. After rinsing, the free rinse liquid and a large portion
of the rinse liquid bound in the items of laundry are removed from
the items of laundry by the at least one spin dryer 11 or another
water-removal device. So much rinse liquid is removed from the
items of laundry in the spin dryer 11 that each kilogram of laundry
contains only approximately 0.6 l of rinse liquid. All the rinse
liquor, specifically the free rinse liquid and a large portion of
the bound rinse liquid, is first combined in the collection tank 19
and from there conducted to the storage tank 21, where the rinse
liquor is temporarily stored separately from the final wash liquor
which is located in storage tank 20. Therefore, 3.1 kg of rinse
liquid per kilogram of laundry enters the storage tank.
[0034] The method according to the invention requires only 3 l of
fresh water per kilogram of washed laundry to wash a respective
batch of laundry. These 3 l per kilogram of laundry are expelled by
the discharge of 2.4 l of prewash water per kilogram of laundry at
the start of the final wash zone 17 and as residual bound rinse
liquid into the items of laundry, which amounts to 0.6 l of water
per kilogram of laundry.
[0035] The rinse tank 21 contains rinse liquor which is colder than
the final wash liquor. When washing cotton, the rinse liquor is at
a temperature of around 29.degree. C., whereas the final wash
liquor is at a higher temperature of approximately 68.degree. C. So
that the temperature of the prewash liquid in the prewash zone 16
is not too high, final wash liquor and rinse liquor from the
water-removal stage are mixed, according to the invention, to form
the prewash liquid which is conducted out of the two collection
tanks 20, 21 upstream of the prewash zone 16. In the exemplary
embodiment shown, all the rinse liquor of 3.1 l of rinse liquid per
kilogram is conducted upstream of the prewash zone 16 to wash-in a
new batch of laundry, to be precise together with a portion of the
final wash liquor contained in the collection tank 20. In the
exemplary embodiment shown, this is approximately 1.8 l of final
wash liquor per kilogram of laundry in order to achieve a stable
liquid balance in the pass-through washing machine 10 and in the
spin dryer 11 and create a sufficiently low temperature.
[0036] FIG. 3 shows the treatment of, specifically the washing and
rinsing of and removal of water from, terry toweling. In principle,
the same method as described above in connection with cotton
laundry is followed. The only difference is in the quantities of
liquid on account of the larger amount of bound liquor in terry
toweling laundry.
[0037] After prewashing, approximately 3.3 l of prewash liquid per
kilogram of laundry are discharged from the drum 12 which is second
as seen in the passage direction 14, specifically with the aid of
the outer drum 18 of the second chamber 15, at the start of the
final wash zone 17. 2 l of final wash liquor per kilogram of
laundry are supplied from the collection tank 20 for the final wash
liquor at the start of the final wash zone 17, so that 5.5 kg of
final wash liquid per kilogram of terry toweling laundry are
available for final washing purposes.
[0038] Before the items of laundry are rinsed, 4.7 l of final wash
liquor per kilogram of laundry are separated in the spin dryer 11
and conducted to the storage tank 20. The final wash liquor in the
storage tank 20 is made up of the free final wash liquor and a
large portion of the bound final wash liquor. The bound final wash
liquor is removed from the terry toweling laundry by the spin dryer
11 to such an extent that only a relatively small portion of bound
final wash liquor of approximately 0.8 l per kilogram of laundry
remains in the terry toweling and has to be rinsed.
[0039] For rinsing purposes, 4 l of fresh water per kilogram of
laundry are fed to the terry toweling laundry. After rinsing, the
rinse liquid, to be precise the free rinse liquid and a large
portion of the bound rinse liquid, is fed to the separate storage
tank 21 for the rinse liquor. This rinse liquor amounts to 4.1 l
per kilogram of terry toweling laundry, specifically the 4 l per
kilogram of fresh water and 0.1 l per kilogram of bound liquor
which has been additionally pressed out of the terry toweling
laundry after the rinse process rather than before the rinse
process.
[0040] In the exemplary embodiment shown, the rinse liquor in the
storage tank 21 is at approximately 27.degree. C., whereas the
final wash liquor in the storage tank 20 is at a temperature of
approximately 68.degree. C.
[0041] In order to wash a new batch of laundry into the first
chamber 15 of the pass-through washing machine 10, a mixture of 2.7
l of final wash liquor per kilogram of laundry from the storage
tank 20 and 4.1 l of rinse liquor from the storage tank 21 are
transported upstream of the first chamber 15 of the pass-through
washing machine 10. This rinse liquor is all the rinse liquor from
the storage tank 21. Therefore, a total of 6.8 l of final wash
liquor and rinse liquor per kilogram of laundry are fed from the
storage tanks 20 and 21 to the prewash zone 16.
[0042] After 3.3 l of prewash water per kilogram of terry toweling
laundry is discharged from the first chamber 15 of the final wash
zone 17, 2 l of final wash liquor per kilogram of terry toweling
laundry are fed from the storage tank 20 for the final wash liquor
to the first chamber 15 of the final wash zone 17, so that 5.5 kg
of final wash liquid per kg of terry toweling laundry are available
here.
[0043] FIG. 4 shows the method according to the invention using the
example of workwear. In this case, the prewash operation is carried
out with 4.6 kg of prewash liquid per kilogram of workwear. The
prewash liquid is at a temperature of approximately 38.degree. C.
All the prewash liquid is taken from the storage tanks 20 and 21
firstly for final wash liquor and secondly for rinse liquor. This
rinse liquor is all the rinse liquor in the storage tank 21,
specifically 3.1 l per kilogram of laundry at a temperature of
approximately 26.degree. C., and a portion of the final wash liquor
from the storage tank 20, specifically 1.5 l per kilogram of work
laundry. The final wash liquor in the storage tank 20 is at a
temperature of approximately 70.degree. C. Accordingly,
approximately 4.6 l per kilogram of workwear are fed to the prewash
zone 16, to be precise a mixture of final wash liquor and rinse
liquor, as a result of which the warmer final wash liquor is
reduced to a temperature of approximately 38.degree. C.
[0044] After prewashing, a portion of the prewash liquid is
discharged to the start of the final wash zone 17 through the outer
drum 18. In the exemplary embodiment shown, this portion is 2.6 l
of prewash liquid per kilogram of work laundry. At the beginning of
the final wash process, approximately 2 l of final wash liquor per
kilogram of workwear is fed from the storage tank 20 for the final
wash liquor to the first chamber 15 of the final wash zone 17.
Therefore, approximately 4 kg of liquid per kilogram of workwear
are present in the final wash zone 17 for final washing
purposes.
[0045] After final rinsing, the items of laundry containing the
bound and unbound final wash liquid leave the pass-through washing
machine 10 via the discharge chute 30. The items of laundry
containing the free and bound final wash liquid therefore enter the
region of the spin dryer 11. Before the items of laundry are
rinsed, all the free final wash liquid is conducted into the
collection tank 19 in the region of the spin dryer 11. The laundry
is also spun to a great extent by the spin dryer 11 such that a
large portion of the bound final wash liquid is removed. A total of
3.5 l of final wash liquid per kilogram of work laundry then enters
the collection tank 19 of the spin dryer 11. From here, all the
final wash liquor, which is removed in the spin dryer 11, of 3.5 l
per kilogram of work laundry is conducted into the storage tank 20
provided for it and temporarily stored there. Before spinning, the
workwear contains only a small fraction of bound final wash liquor,
to be precise approximately 0.5 l per kilogram of work laundry.
[0046] For rinsing purposes, approximately 3 l of fresh water per
kilogram of workwear is fed to the spin dryer 11. The wash liquor
which is produced during rinsing, specifically all the fresh water
fed in and also 0.1 l of rinse water per kilogram of workwear from
the bound liquor, that is to say a total of 3.1 l of wash liquor
per kilogram of workwear, are temporarily stored in the separate
storage tank 21 separately from the final wash liquid. The storage
tank 20 then contains approximately 3.5 l of final wash liquor per
kilogram of workwear at a temperature of approximately 70.degree.
C., and the second storage tank 21 contains 3.1 l of rinse liquor
per kilogram of workwear at a temperature of approximately
27.degree. C. All the rinse liquor from the storage tank 21 is used
for the prewash operation of the next batch of laundry. In
addition, 1.5 l of final wash liquor from the storage tank 20 per
kilogram of laundry are used for the prewash operation. As a
result, the warmer final wash liquor is cooled from 67.degree. C.
to approximately 38.degree. C., that is to say a temperature which
can be used for the prewash operation without the risk of protein
flecks forming. The residual final wash liquor from the storage
tank 20, specifically 2 l per kilogram of laundry, is used at the
start of the final wash zone 17.
[0047] The method according to the invention permits the process to
manage with a fresh water requirement of 3 l per kilogram of
workwear for each wash cycle. These 3 l replace the 2.6 l of
prewash liquid per kilogram of workwear discharged for each wash
cycle and the bound liquor, which is expelled from the rinsed
workwear, of 0.4 l of rinse water per kilogram of workwear.
LIST OF REFERENCE SYMBOLS
[0048] 10 Pass-through washing machine [0049] 11 Spin dryer [0050]
12 Drum [0051] 13 Partition wall [0052] 14 Passage direction [0053]
15 Chamber [0054] 16 Prewash zone [0055] 17 Final wash zone [0056]
18 Outer drum [0057] 19 Collection tank [0058] 20 Storage tank
[0059] 21 Storage tank [0060] 22 Supply line [0061] 23 Valve [0062]
24 Outflow line [0063] 26 Feed funnel [0064] 27 Outflow line [0065]
28 Outflow line [0066] 29 Valve [0067] 30 Discharge chute
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