U.S. patent application number 12/106303 was filed with the patent office on 2009-04-23 for method and apparatus for the wet treatment of laundry articles.
Invention is credited to Wilhelm Bringewatt, Engelbert Heinz.
Application Number | 20090100607 12/106303 |
Document ID | / |
Family ID | 39673400 |
Filed Date | 2009-04-23 |
United States Patent
Application |
20090100607 |
Kind Code |
A1 |
Bringewatt; Wilhelm ; et
al. |
April 23, 2009 |
METHOD AND APPARATUS FOR THE WET TREATMENT OF LAUNDRY ARTICLES
Abstract
In the washing and drainage of laundry articles, treatment
liquid which contains still unspent wash-active substances occurs
at the end of the washing operation. These substances have hitherto
been conducted, if appropriate after neutralization, into the
discharge together with the treatment liquid. This known procedure
has an adverse effect on the efficiency of the washing operation.
According to the invention, spent wash-active substances are
removed from the treatment liquid separated from the laundry
articles after the washing operation. This takes place by means of
precision filtration, in which only the spent wash-active
substances which are larger due to the absorption of dirt from the
washing operation are filtered out of the treatment liquid, but not
the unspent wash-active substances having a smaller particle size.
These can be reused, together with the treatment liquid, for a
subsequent washing operation.
Inventors: |
Bringewatt; Wilhelm; (Porta
Westfalica, DE) ; Heinz; Engelbert; (Vlotho,
DE) |
Correspondence
Address: |
SMITH, GAMBRELL & RUSSELL
SUITE 3100, PROMENADE II, 1230 PEACHTREE STREET, N.E.
ATLANTA
GA
30309-3592
US
|
Family ID: |
39673400 |
Appl. No.: |
12/106303 |
Filed: |
April 20, 2008 |
Current U.S.
Class: |
8/158 ;
68/12.13 |
Current CPC
Class: |
D06F 39/006 20130101;
D06F 31/005 20130101; D06F 2105/06 20200201; D06F 2105/52 20200201;
D06F 2103/22 20200201; D06F 34/22 20200201; D06F 33/46 20200201;
D06F 2105/02 20200201 |
Class at
Publication: |
8/158 ;
68/12.13 |
International
Class: |
D06F 39/10 20060101
D06F039/10 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 20, 2007 |
DE |
102007019193.8 |
Claims
1. Method for the wet treatment of laundry articles, the laundry
articles being at least washed in a treatment liquid containing at
least one wash-active substance, and thereafter the treatment
liquid being at least partially separated from the treated laundry
articles, wherein spent wash-active substances are removed at least
for the most part from the treatment liquid separated from the
laundry articles.
2. Method according to claim 1, wherein at least one spent
wash-active substance is removed at least for the most part from
the treatment liquid after different treatment steps.
3. Method according to claim 1, wherein the at least one spent
wash-active substance is removed at least for the most part from
the treatment liquid after at least one pre-wash.
4. Method according to claim 1, wherein the at least one spent
wash-active substance is removed at least for the most part from
the treatment liquid a plurality of times.
5. Method according to claim 1, wherein, during a rinsing of the
washed laundry articles in a drainage device, at least one spent
wash-active substance is removed at least for the most part from
the treatment liquid separated from the laundry articles after
washing and also from the treatment liquid separated from the
laundry articles before rinsing in the drainage device.
6. Method according to claim 1, wherein the at least one spent
wash-active substance is separated at least for the most part from
the treatment liquid by filtration.
7. Method according to claim 6, wherein pre-filtration is carried
out before at least one spent wash-active substance is filtered out
of the treatment liquid.
8. Method according to claim 6, wherein the filtering-out of at
least a large part of at least one spent wash-active substance from
the treatment liquid takes place by means of micro-filtration.
9. Method according to claim 6, wherein, during filtration, spent
wash-active substances with a particle size of 0.005 .mu.m to 10
.mu.m are removed at least for the most part from the treatment
liquid.
10. Method for the wet treatment of laundry articles, the laundry
articles being at least washed in a treatment liquid containing at
least one wash-active substance, and thereafter the treatment
liquid being separated at least partially from the laundry
articles, wherein, during treatment, the content of the at least
one wash-active substance still contained in the treatment liquid
is determined.
11. Method according to claim 10, wherein, after the removal of at
least a large part of spent wash-active substances from the
treatment liquid, the content of at least one wash-active substance
still contained in the treatment liquid is determined.
12. Method according to claim 10, wherein the measured content of
the at least one wash-active substance still contained in the
treatment liquid is compared with a desired content of the
respective wash-active substance in the treatment liquid, and, if
the desired content is undershot, a corresponding quantity of at
least one wash-active substance is added to the treatment
liquid.
13. Apparatus for the wet treatment of laundry articles, with a
washing machine having a drum (13) drivable in rotation and with a
drainage device following the washing machine, wherein at least one
filter (52, 57) for removing at least one spent wash-active
substance in the treatment liquid is assigned to an outflow line,
returned to the start of a washing zone (47, 48) for the treatment
liquid from the drum (13) and to an outflow line, returned to the
start of the washing zone (47, 48) from the drainage device.
14. Apparatus for the wet treatment of laundry articles with a
washing machine having a drum (13) drivable in rotation and with a
drainage device following the washing machine, wherein at least one
filter (26, 32) for the removal of at least one spent wash-active
substance from the treatment liquid is assigned to at least one
outflow line, returned to the start of the washing zone (17, 18)
for treatment liquid from the drum (13).
15. Apparatus according to claim 13, wherein at least one
pre-filter (25, 31, 51, 56) is arranged upstream of the filter (26,
32, 52, 57) for removing at least one spent wash-active substance
from the treatment liquid.
16. Apparatus according to claim 15, wherein the filter (26, 32,
52, 57) is designed as a micro-filter.
17. Apparatus according to claim 15, wherein the filter (26, 32,
52, 57) is designed as a membrane filter.
18. Apparatus according to claim 17, wherein the membrane filter is
assigned at least one supporting body.
19. Apparatus according to claim 14, wherein at least one
pre-filter (25, 31, 51, 56) is arranged upstream of the filter (26,
32, 52, 57) for removing at least one spent wash-active substance
from the treatment liquid.
20. Apparatus according to claim 19, wherein the filter (26, 32,
52, 57) is designed as a micro-filter.
21. Apparatus according to claim 19, wherein the filter (26, 32,
52, 57) is designed as a membrane filter.
22. Apparatus according to claim 21, wherein the membrane filter is
assigned at least one supporting body.
Description
STATEMENT OF RELATED APPLICATIONS
[0001] This patent application is based on and claims convention
priority on German Patent Application No. 10 2007 019 193.8 having
a filing date of 20 Apr. 2007, which is incorporated herein by this
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The invention relates to methods for the wet treatment of
laundry articles, in particular for the at least washing, of
laundry articles, the laundry articles being at least washed in a
treatment liquid containing at least one wash-active substance, and
thereafter the treatment liquid being at least partially separated
from the treated laundry articles. The invention relates,
furthermore, to apparatuses for the wet treatment of laundry
articles, in particular for the at least washing of laundry
articles, with a washing machine having a drum drivable in rotation
and with a drainage device following the washing machine.
[0004] 2. Prior Art
[0005] In the wet treatment, in particular washing, of laundry
articles, which may be all types of articles to be washed,
treatment liquid containing wash-active substances are used. After
washing, the treatment liquid not bound in the laundry articles,
what is known as the free liquor, is separated from the laundry
articles. The treatment liquid then contains spent wash-active
substances which have absorbed the dirt from the laundry articles,
but also still unspent wash-active substances.
[0006] It has hitherto been customary to discharge the used
treatment of liquid at least partially as sewage. The unspent
wash-active substances are consequently lost. Depending on the type
of wash-active substances, it may be necessary to neutralize them
before they are discharged into, for example, a sewage conduit.
Finally, the discharge of the used treatment liquid makes it
necessary to employ fresh water again for the next washing
operation. For the reasons mentioned, the previous discharge of the
used treatment liquid is inefficient.
BRIEF SUMMARY OF THE INVENTION
[0007] Proceeding from the above, the object on which the invention
is based is to provide methods and apparatuses for the wet
treatment of laundry, which have higher efficiency, as compared
with known methods and apparatuses.
[0008] A method for achieving this object is a method for the wet
treatment, in particular for the at least washing, of laundry
articles, the laundry articles being at least washed in a treatment
liquid containing at least one wash-active substance, and
thereafter the treatment liquid being at least partially separated
from the treated laundry articles, characterized in that spent
wash-active substances are removed at least for the most part from
the treatment liquid separated from the laundry articles.
Accordingly, spent wash-active substances are removed from the
treatment liquid separated from the laundry articles. The spent
wash-active substances bind the dirt which the treatment liquid has
entrained from the previous washing operation. Thus, by the spent
wash-active substances being removed, the dirt is removed at least
for the most part from the treatment liquid. The treatment liquid
having the remaining unspent wash-active substances can then be
reused for a subsequent washing operation. As a result, unspent
wash-active substances are not lost, and they do not have to be
neutralized even for the discharge of the treatment liquid into the
sewage system. Above all, by virtue of the method according to the
invention, the consumption of fresh water can be reduced, because
the treatment liquid, together with the unspent wash-active
substances, can be implemented anew for washing the laundry
articles.
[0009] There is provision, furthermore, for removing the spent
wash-active substances from the treatment liquid after various
treatment steps of the laundry articles, for example after the
pre-wash and after the clear wash. Thus, the entire treatment
liquid occurring during a multi-stage washing operation, together
with the wash-active substances still contained in it, can be
reused.
[0010] According to a further preferred refinement of the method,
there is provision for removing the spent wash-active substances
from the treatment liquid a plurality of times. Preferably, during
the rinsing of the washed laundry articles in a drainage device,
there is provision for removing spent wash-active substances from
the treatment liquid separated from the laundry articles after
washing and also from the treatment liquid separated from the
drainage device before rinsing in the drainage device. This
two-stage removal of the spent wash-active substances from the
treatment liquid optimally makes available treatment liquid freed
of spent wash-active substances and containing essentially only
unspent wash-active substances present in it, for a subsequent
washing operation, specifically, in particular, for a washing
operation with a separate pre-wash and clear wash. The fresh-water
requirement therefore amounts to only a fraction of the treatment
liquid required for the subsequent washing operation, and, if
necessary, only the wash-active substances actually spent have to
be replaced.
[0011] In the preferred method, the spent wash-active substances
are separated from the treatment liquid by filtration, preferably
precision filtration. Since, due to dirt absorption, spent
wash-active substances have a particle size which overshoots the
particle size of unspent wash-active substances, separation between
the unspent and the spent wash-active substances can take place by
filtration. Since the particle sizes differ from one another only
slightly, above all lie only in the micrometer range, precision
filtration is suitable particularly for the effective removal of at
least a large part of the spent wash-active substances from the
treatment liquid.
[0012] An advantageous development of the method provides for
carrying out pre-filtration before spent wash-active substances are
filtered out of the treatment liquid. During this pre-filtration,
larger dirt particles are eliminated which, during the subsequent
filtering-out of spent wash-active substances, in particular by
precision filtration, can no longer have a disturbing effect by
loading or even clogging the sensitive filters for precision
filtration. After pre-filtration, therefore, a particularly
effective and reliable filtration of at least a large part of the
smaller spent wash-active substances is possible.
[0013] The removal of spent wash-active substances from the
treatment liquid expediently takes place by means of micro- and/or
ultra-filtration. Spent wash-active substances can thereby be
removed from the treatment liquid in a directed manner. These are
preferably particles with a size of between 10 .mu.m and 0.005
.mu.m, preferably 1 .mu.m to 0.5 .mu.m. This is the typical
particle size of spent wash-active substances, so that at least a
large part of the spent wash-active substances is removed in this
way, but not the smaller unspent wash-active substances.
[0014] A further method for achieving the object mentioned in the
introduction, which may also be a preferred development of the
method described above, is a method for the wet treatment, in
particular for the at least washing, of laundry articles, the
laundry articles being at least washed in a treatment liquid
containing at least one wash-active substance, and thereafter the
treatment liquid being separated at least partially from the
laundry articles, characterized in that, during treatment, the
content of the at least one wash-active substance still contained
in the treatment liquid is determined. Accordingly, there is
provision, after the removal of spent wash-active substances from
the treatment liquid, for determining the content of the spent
wash-active substances still contained in it. This may take place,
for example, by means of what is known as a bubble tensometer, for
example an H.sub.2O.sub.2 sensor or a Cl sensor. Other measuring
methods or sensors suitable for the particle size of unspent
wash-active substances may also be considered.
[0015] A further refinement of the method provides for comparing
the measured content of the unspent wash-active substances still
present in the treatment liquid with a desired content of
wash-active substances in the treatment liquid. If it is in this
case established that the measured content of the unspent
wash-active substances still contained in the treatment liquid lies
below the desired content, fresh wash-active substances are added
to the treatment liquid in a directed manner. This secondary
metering takes place to an extent such that the treatment liquid
again has a content of unspent wash-active substances which
corresponds to the desired content of unspent wash-active
substances in the treatment liquid or lies somewhat above it,
preferably within an excess range selected in a directed
manner.
[0016] An apparatus for achieving the object mentioned in the
introduction, having a washing machine, in particular
continuous-flow washing machine, having a drum drivable in
rotation, and a drainage device, for example a drainage press or a
laundry centrifuge, is an apparatus for the wet treatment of
laundry articles, in particular for the at least washing of laundry
articles, with a washing machine having a drum drivable in rotation
and with a drainage device following the washing machine,
characterized in that at least one filter for removing at least one
spent wash-active substance in the treatment liquid is assigned to
an outflow line, returned to the start of a washing zone for the
treatment liquid from the drum and to an outflow line, returned to
the start of the washing zone from the drainage device.
Accordingly, there is provision for assigning a filter for the
removal of spent wash-active substances from the treatment liquid
in each case to an outflow line, returned to the drum, for the
treatment liquid from the drum and to an outflow line, returned to
the drum, for the treatment liquid from the drainage device. Thus,
the spent wash-active substances are to be filtered out wherever
used treatment liquid not found in laundry articles and having both
unspent and spent wash-active substances occurs. As a result, both
the treatment liquid discharged in the washing machine and the
treatment liquid occurring in the region of the drainage press are
prepared for reuse. Since the treatment liquid from the washing
machine and from the drainage device is prepared, prepared
treatment liquid without spent wash-active substances occurs at
various points and can be supplied again to different points in the
washing machine in a directed manner, in particular to the pre-wash
and clear wash. The invention is therefore suitable particularly
for apparatuses for the washing, rinsing and drainage of laundry
articles in which rinsing takes place in the drainage device.
[0017] A further apparatus for the at least washing of laundry
articles, which serves for achieving the object mentioned in the
introduction, is an apparatus for the wet treatment of laundry
articles, in particular for the at least washing of laundry
articles, with a washing machine having a drum drivable in rotation
and with a drainage device following the washing machine,
characterized in that at least one filter for the removal of at
least one spent wash-active substance from the treatment liquid is
assigned to at least one outflow line, returned to the start of the
washing zone for treatment liquid from the drum. In this apparatus,
there is provision for assigning a filter for the removal of spent
wash-active substances from the treatment liquid to at least one
outflow line, returned to the start of the drum, for the treatment
liquid from the drum. Thus, the entire treatment liquid which
occurs during the washing of the laundry articles can be freed of
spent wash-active substances before the rinsing of the laundry
articles. Preferably, treatment liquid occurs after the pre-wash
and the clear wash. The spent wash-active substances are then
removed from these separately occurring treatment liquids before
the treatment liquid is employed anew for washing. The treatment
liquids freed at least for the most part of spent wash-active
substances can be supplied, as required, to the laundry articles
before the pre-wash and/or before the clear wash. For example, the
treatment liquid, having higher temperatures, from the preceding
clear wash can be supplied with a renewed clear wash after the
separation of spent wash-active substances, while the treatment
liquid from the pre-wash is supplied for the pre-wash again. Thus,
no appreciable energy needs to be supplied to the respective
treatment liquids in order to use them again. In particular, the
cold treatment liquid from the pre-wash does not have to be heated
in order to be supplied to the clear-wash.
[0018] In a preferred refinement of the apparatus, filters for the
separation of spent wash-active substances from the treatment
liquid are used, which are designed as micro- and/or ultra-filters.
Above all, membrane filters may be considered as such filters.
These membrane filters are preferably provided with supporting
bodies, and these may be ceramic supporting bodies. The filters may
be designed as what are known as cross-flow filters or as dead-end
filters.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Preferred exemplary embodiments of the invention are
explained in more detail below with reference to the drawing in
which:
[0020] FIG. 1 shows a diagrammatic side view of the apparatus
according to a first exemplary embodiment of the invention.
[0021] FIG. 2 shows a diagrammatic side view of the apparatus
according to a second exemplary embodiment of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0022] The apparatuses shown here form a washing line for the wet
treatment of laundry articles. The wet treatment is washing,
rinsing and drainage. All textile articles normally to be washed
are considered as laundry articles, specifically, in particular,
clothing, including occupational clothing, table laundry, bed
laundry, foot mats, entry mats and the like.
[0023] The apparatuses illustrated in the figures have a
continuous-flow washing machine and a drainage device. The drainage
device may be a centrifuge or a drainage press shown in the
figures.
[0024] The continuous-flow washing machine 10 of FIG. 1 has a
cylindrical drum 13 driveable in rotation about a preferably
horizontal axis of rotation 12. In the drum 13, a plurality of
chambers 16 succeeding one another in the flow direction 15 of the
laundry articles, not shown, through the drum 13 are formed by
transversely directed partitions 14.
[0025] In the drum 13 of the continuous-flow washing machine 10 of
the exemplary embodiment of FIG. 1, essentially three treatment
zones are located, specifically a pre-washing zone 17, a following
clear-washing zone 18 and, finally, a rinsing zone 19 arranged at
the end of the drum 13. In the continuous-flow washing machine 10
of FIG. 1, both the pre-washing zone 17 and the clear-washing zone
18 have two successive chambers 16. By contrast, the rinsing zone
19 has only a single chamber 16. Overall, therefore, the
continuous-flow washing machine 10 has five chambers 16. However,
the invention is not restricted to this. Instead, the number of
chambers 16 may deviate from the exemplary embodiment shown. Above
all, the pre-washing zone 17, the clear-washing zone 18 and the
rinsing zone 19 may have a larger or smaller number of chambers
than illustrated in FIG. 1.
[0026] The continuous-flow washing machine 10 is arranged
downstream of the drainage press 16, as seen in the flow direction
15. The wash and rinsed laundry articles pass out of the
continuous-flow washing machine 10 via the unloading chute 20,
arranged at the end of the latter, into the drainage press 11. The
drainage press 11 is designed in a basically known way. Thus, the
drainage press 11 has a press housing open at the top and at the
bottom, preferably a cylindrical press basket 21 with a
liquid-impermeable cylindrical surface area, and a press plunger 22
which is movable up and down in the press basket 21 and which is
illustrated merely in passing (by dashes) in FIG. 1. The press
plunger 22 can be moved up by means of a hydraulic cylinder to an
extent such that, particularly for loading the drainage press 11,
it is located above the press basket 21 and consequently completely
releases an upper orifice of the press basket 21. To drain the
laundry articles, the press plunger 22 can be pressed into the
press basket 21, the press plunger 22 being sealed off, essentially
liquid-tight, inside the surface area of the press basket 21. Below
the press basket 21 is located a collecting tank 23 or another
device for intercepting the treatment liquid pressed out of the
laundry articles.
[0027] An outflow line 24 branches off from the end of the
pre-washing zone 17. The outflow line 24 leads to a pre-filter 25
and from this to a filter 26 for separating spent wash-active
substances from the treatment liquid discharged out of the
pre-washing zone 17 through the outflow line 24. The outflow line
24 issues from the filter 26 into a branch point 27. A return line
28 leads from the branch point 27 to the start of the
continuous-flow washing machine 10, to be precise, in the exemplary
embodiment shown, to an inflow funnel 29, by means of which the
laundry articles to be washed can be supplied to the drum 13.
[0028] At the end of the clear-washing zone 18 is arranged a
further outflow line 30 which again leads to a pre-filter 31 and
thereafter to a filter 32 for separating spent wash-active
substances from the treatment liquid. The outflow line 30 leads
from the filter 32 further on to a branch point 33. The filtered
treatment liquid, together with remaining unspent wash-active
substances, but filtered-off spent wash-active substances, can be
supplied from the branch point 33 via a connecting line 34 to the
branch point 27, from where the filtered treatment liquid coming
from the clear-washing zone 18 can be supplied via the return line
28 to the inflow funnel 29 upstream of the drum 13 of the
continuous-flow washing machine 10.
[0029] A second line, to be precise a return line 35, branches off
from the filter 32. This return line 35 leads via a further branch
point 36 to the return line 37, from which the filtered treatment
liquid, without spent wash-active substances, but still with a
residue of unspent wash-active substances, can be returned to the
start of the clear-washing zone 18.
[0030] The rinsing zone 19 has an overflow 38 which leads to a
collecting tank 39. An intermediate line 40 branches off from the
collecting tank 39 and leads to the branch point 36 in the return
line 37.
[0031] Two return lines 41 and 42 branch off from the collecting
tank 23 of the drainage press 11. The return line 41 leads to the
branch point 33, from where the treatment liquid can be supplied
from the collecting tank 23 to the inflow funnel 29 upstream of the
drum 13. The return line 42 from the collecting tank 23 is led back
to the rinsing zone 19, that is to say to the last chamber 16 of
the continuous-flow washing machine 10.
[0032] The filters 26 and 32 are designed in a special way. These
may be the same filters which allow a precision filtration of the
treatment liquid originating from the pre-washing zone 17 and the
clear-washing zone 18. This treatment liquid is washing water which
is enriched with wash-active substances, some of which are spent as
a result of dirt absorption, while some excess wash-active
substances are still unspent even after the pre-wash and
clear-wash. The filters 26 and 32 separate only spent wash-active
substances from the treatment liquid, but no unspent wash-active
substances having a lower particle size. For this purpose, the
filters 26 and 32 are designed as micro- and/or ultra-filters which
are suitable for filtering out particles of the size of the spent
wash-active substances from the liquid. Such filters 26 and 32 make
it possible to filter out from the treatment liquid particles with
a size of 0.005 .mu.m to 10 .mu.m, preferably 0.5 .mu.m to 1
.mu.m.
[0033] The filters 26 and 32 are preferably membrane filters.
However, other filters may also be considered which are suitable
for carrying out precision filtration, above all micro- and/or
ultra-filtration, in particular for filtering out particles of the
abovementioned size ranges from the treatment liquid. The membrane
filters are preferably designed as wound filters and/or are
provided with supporting bodies. The supporting bodies are
primarily ceramic supporting bodies.
[0034] The filters 26 and 32 may operate according to the
cross-flow principle, but also according to the dead-end
principle.
[0035] The method according to the invention proceeds, by means of
the above-described apparatus according to FIG. 1, as follows:
[0036] The laundry articles to be washed pass via the inflow funnel
29 into the entry-side end of the drum 13 of the continuous-flow
washing machine 10. The laundry articles are in this case flushed
through with filtered treatment liquid both from the pre-washing
zone 17 and the clear-washing zone 18 and from the drainage press
11. The treatment liquid is, as a rule, water which has a certain
content of wash-active substances, as a rule washing agents,
surfactants and the like. The dirt occurring particularly during
the washing of the laundry articles is bound by the wash-active
substances, with the result that these increase in size. Such
wash-active substances are spent as a result of the binding of
dirt. The water for forming the treatment liquid usually contains
excess wash-active substances, so that, after the washing of the
laundry, the treatment liquid contains not only spent wash-active
substances which have bound the dirt, but also still unspent
wash-active substances.
[0037] After the pre-wash of the laundry articles, at the end of
the pre-washing zone 17 the treatment liquid is first pre-filtered
at the pre-filter 25 by the outflow line 24. In this case,
particles which are larger than the particles of spent and unspent
wash-active substances are removed. Subsequently, the treatment
liquid is freed in the filter 26, at least for the most part, of
spent wash-active substances which are enriched with dirt from the
pre-washing zone 17. Only spent wash-active substances are
separated from the treatment liquid in the filter 26, but no
unspent wash-active substances. Since the unspent wash-active
substances have not absorbed any dirt and therefore are smaller
than the spent wash-active substances, the filter 26 leaves the
still unspent wash-active substances in the treatment liquid. The
larger particles filtered off by the pre-filter 25 and the spent
wash-active substances separated from the treatment liquid by the
filter 26 are discharged respectively at the pre-filter 25 and at
the filter 26. Treatment liquid containing only or essentially only
still unspent wash-active substances leaves the filter 26. This
treatment liquid is supplied via the branch point 27 and the return
line 28 to the inflow funnel 29 upstream of the continuous-flow
washing machine 10, in order to flush through laundry articles
which are to be washed by the continuous-flow washing machine 10 in
the next washing cycle.
[0038] The treatment liquid is separated from the washed laundry
articles also at the end of the clear-washing zone 18. This
treatment liquid passes via the outflow line 30 to the filter 31
and thereafter to the filter 32. At the pre-filter 31, in the same
way as at the pre-filter 25, larger particles are filtered off as
spent wash-active substances, while the filter 32, again in the
same way as the filter 26, separates spent wash-active substances
from the treatment liquid. Treatment liquid leaving this filter 32
and having essentially only unspent wash-active substances passes,
as required, either via the branch point 33, the connecting line 34
and the return line 28 to the inflow funnel 29 upstream of the drum
13 or via the return line 35, the branch point 36 and the return
line 37 to the start of the clear-washing zone 18. By means of a
corresponding valve, not shown, and a control assigned to the
latter, treatment liquid containing essentially only unspent
wash-active substances is conducted in a directed manner to the
inflow funnel 29 or to the start of the clear-washing zone 18.
[0039] Excess rinsing liquid passes from the overflow 38 of the
rinsing zone 19 into the collecting tank 39. The rinsing water may
be conducted from the collecting tank 39, as required, via the
intermediate line 40 and the branch point 36 through the return
line 37 to the start of the clear-washing zone 18.
[0040] Rinsing liquid pressed out by the drainage press 11 passes
from the collecting tank 23 of the drainage press 11 either via the
return line 41 to the branch point 33 and from there via the
connecting line 34, the branch point 27 and the return line 28 to
the inflow funnel 29 upstream of the drum 13 or via the return line
42 back to the rinsing zone 19. The rinsing water from the
collecting tank 23 below the drainage press 11 may be conducted, as
required, either to the inflow funnel 29 or to the rinsing zone 19
by means of corresponding valves, not shown.
[0041] The method described makes it possible for treatment liquid
freed of spent wash-active substances, in particular spent
surfactants, to be returned from the pre-washing zone 17 and the
clear-washing zone 18 to the inflow funnel 29 upstream of the
continuous-flow washing machine 10, so that this treatment liquid
freed of spent wash-active substances can be reused for washing a
subsequent batch of laundry articles.
[0042] According to a method which constitutes a specific invention
and which preferably advantageously supplements the method
described above, unspent wash-active substances in the filtered
treatment liquid are measured during the operation of the
apparatus, preferably continuously, for example by means of a
bubble tensometer, an H.sub.2O.sub.2 sensor, a Cl sensor or the
like. The measured concentration of unspent wash-active substances
is then compared with a desired concentration of wash-active
substances in the treatment liquid. If it is established from this
comparison that the concentration of the remaining wash-active
substances still present in the treatment liquid lies below the
desired concentration, fresh wash-active substances are admixed to
the treatment liquid, specifically preferably in the region of the
return line 28. This admixing of new wash-active substances takes
place to the extent such that the desired concentration of
wash-active substances is produced again in the returned treatment
liquid or is overshot preferably within a defined range.
[0043] By virtue of the methods according to the invention, still
unspent wash-active substances in the treatment liquid are not
lost; instead, they can be spent virtually completely.
Consequently, no treatment liquid with unspent wash-active
substances is conducted into the discharge. Above all, remaining
wash-active substances in the treatment liquid do not need to be
neutralized before being led away into the discharge. Moreover, the
fresh-water requirement can be lowered considerably due to the
reuse of the treatment liquid still containing a residue of unspent
wash-active substances. Since the fresh-water requirement is thus
reduced as a result of the methods according to the invention and
all unspent wash-active substances are fully utilized, the
efficiency of the washing process is markedly increased.
[0044] FIG. 2 shows an apparatus according to a second exemplary
embodiment of the invention. This apparatus also has a
continuous-flow washing machine 45 and a drainage press 46 or
another drainage device, for example a laundry centrifuge. The
continuous-flow washing machine 45 is designed, in principle, in
the same way as the continuous-flow washing machine 10. The same
reference numerals are therefore used for identical parts. In the
exemplary embodiment shown, the continuous-flow washing machine 45
also has five chambers 16 succeeding one another in the flow
direction 15. However, the five chambers 16 in the continuous-flow
washing machine 45 form only a pre-washing zone 47 consisting of
two chambers 16 and a clear-washing zone 48 consisting of three
chambers 16. However, the number of chambers of the pre-washing
zone 47 and of the clear-washing zone 48 may deviate from the
exemplary embodiment shown, to be precise may be both larger and
smaller. As a rule, however, the clear-washing zone 48 has a larger
number of chambers than the pre-washing zone 47.
[0045] The continuous-flow washing machine 45 has no rinsing zone.
Rinsing therefore does not take place in the continuous-flow
washing machine 45. Instead, in the apparatus shown here, rinsing
takes place in the drainage device, that is to say, in the
exemplary embodiment shown, in the draining press 46. This
therefore has two functions, to be precise serves for separating a
larger part of the treatment liquid (clear-washing liquid) from the
clear-washing zone 48 of the continuous-flow washing machine 45 and
for the subsequent rinsing of the laundry articles, for which
purpose fresh water can be supplied to the drainage press 46 via a
supply line 49 shown merely in passing in FIG. 2.
[0046] The continuous-flow washing machine 45 has at the end of the
pre-washing zone 47 an outflow line 50 which leads to a pre-filter
51 and from this to a filter 52 serving particularly for precision
filtration. The pre-filter 51 and the filter 52 are designed in the
same way as the pre-filters 25 and 31 and the filters 26 and 32 of
the first exemplary embodiment and have the same purpose. The
treatment liquid coming from the pre-washing zone 17 and freed of
spent wash-active substances passes from the filter 52 via a branch
point 53 to the return line 54 which leads to the inflow funnel 29
upstream of the continuous-flow washing machine 45.
[0047] An outflow line 55 runs from the collecting tank 23 below
the drainage press 46 to a pre-filter 56 and to a following filter
57. The pre-filter 56 and the filter 57 are designed in the same
way as the pre-filter 51 and the filter 52, to be precise serve
first for separating coarser particles from the treatment liquid
and then separating spent wash-active substances. The treatment
liquid freed at least for the most part of spent wash-active
substances can pass from the filter 57 via a connecting line 58 and
a branch point 59 to the branch point 53 and from there via the
return line 54 to the inflow funnel 29 of the continuous-flow
washing machine 45. Furthermore, an outflow line 60 emanates from
the filter 57 and is led back to the start of the pre-washing zone
17. By means of valves assigned to the connecting line 58 and to
the outflow line 60 at the outlet of the filter 57, the liquid
freed of spent wash-active substances can be conducted via a
corresponding control either upstream of the continuous-flow
washing machine 45 or to the start of the pre-washing zone 47.
[0048] A second connecting line 61 branches off from the collecting
tank 23 below the drainage press 46 and leads to the branch point
59 and from there via the branch point 53 and the return line 54 to
the inflow funnel 29 upstream of the continuous-flow washing
machine 54. The connecting lines 58 and 61 of the collecting tank
23 are also provided with valves, with the result that the outflow
of treatment liquid from the collecting tank 23 can be controlled
in a directed manner, so that the treatment liquid can pass out of
the collecting tank 23, even bypassing the pre-filter 56 and the
filter 57, to upstream of the continuous-flow washing machine
45.
[0049] The method according to the invention is described in more
detail below with reference to the continuous-flow washing machine
45 and to the drainage press 46 following the latter.
[0050] The pre-filters 51 and 56 and the filters 52 and 57 serving
for precision filtration have the same function as the pre-filters
25 and 31 and filters 26 and 32 in the method described further
above in connection with FIG. 1. Accordingly, the pre-filters 51
and 56 serve for separating larger particles from the treatment
liquid before the smaller spent wash-active substances, but not the
even smaller unspent wash-active substances, are separated at least
for the most part from the treatment liquid by the filters 52 and
57.
[0051] The liquid prepared by the pre-filter 51 and by the filter
52 and coming from the end of the pre-washing zone 17 passes via
the return line 54 to the inflow funnel 29 upstream of the
continuous-flow washing machine 45. This treatment liquid
containing essentially only unspent wash-active substances is used
for flushing through laundry articles which are to be treated in a
next washing cycle.
[0052] The washed laundry articles pass out of the clear-washing
zone 48 of the continuous-flow washing machine 45 into the drainage
press 46 downstream of the continuous-flow washing machine 45 or
into another drainage device. The treatment liquid from the
clear-washing zone 48 is first separated by the drainage press 46
from the laundry articles, with the exception of the residual
moisture. The treatment liquid from the clear-washing zone 48,
which contains spent and unspent wash-active substances, is
intercepted in the collecting tank 23 below the drainage press 46
and is first conducted from the said collecting tank through the
outflow line 55 to the pre-filter 56 and is subsequently supplied,
pre-filtered by the latter by the separation of larger particles,
to the filter 57 which at least for the most part removes spent
wash-active substances from the treatment liquid. Thereafter, part
of the prepared treatment liquid, without substantial spent
wash-active substances, is conducted via the connecting line 58 and
the branch point 59 of the return line 54 to the inflow funnel 29.
In this case, the prepared treatment liquid originating from the
pre-washing zone 47 is topped up by the same fraction which was
removed from the treatment liquid from the pre-washing zone 47
during pre-filtration in the pre-filter 51 and in the filter 52.
The remaining part of the treatment liquid, separated from the
laundry articles by the drainage press 46, from the clear-washing
zone 48 in the collecting tank 23 is conducted downstream of the
filter 57 through the outflow line 60 to the start of the
clear-washing zone 48.
[0053] After the drainage press 46 has separated the treatment
liquid from the clear-washing zone 48 out of the laundry articles,
with the exception of the residual moisture, and this treatment
liquid has been removed from the collecting tank 23 and prepared by
means of the pre-filter 56 and the filter 57, the rinsing of the
laundry articles takes place in the drainage press 46. For this
purpose, fresh water is supplied via the supply line 49 to the
drainage press 46 and is pressed through the laundry articles by
the drainage press, rinsing of the laundry articles taking place.
The rinsing liquid pressed out of the laundry articles during
rinsing is then intercepted in the collecting tank 23 and is
conducted via the connecting line 61, without filtration, via the
branch points 53 and 59 through the return line 54 to the inflow
funnel 29 upstream of the continuous-flow washing machine 45.
[0054] There may preferably be arranged in the outflow line 55 at
least one further collecting tank, in which treatment liquid from
the clear-washing zone 48 is intermediately stored until it is
filtered by the pre-filter 56 and the filter 57 and supplied for
further use. As a result, the collecting tank 23 can be emptied of
the laundry articles immediately after the separation of the
treatment liquid from the clear-washing zone 48, so that the
collecting tank 23 is available in a short time for the reception
of rinsing liquid.
[0055] The method according to the invention is particularly
suitable for the apparatus of FIG. 2, in which the continuous-flow
washing machine 45 has only a pre-washing zone 47 and a
clear-washing zone 48, but the rinsing of the laundry articles
takes place in the drainage press 46. Here, treatment liquid from
the clear-washing zone 48 and rinsing liquid from the drainage
press 46 occur briefly in succession, so that prepared treatment
liquid with only unspent wash-active substances is available via
the rinsing liquid at the appropriate time for an operation for
washing a following batch of laundry articles. The fresh-water
requirement in the apparatus of FIG. 2 is thereby reduced to a
minimum. In many instances, no fresh water at all needs to be
supplied, because the liquid discharged by the residual moisture,
together with the ready-rinsed and drained laundry articles, and
the liquid separated at the pre-filters 51 and 56 and at the
filters 52 and 57 with residual particles and spent wash-active
substances can be used by the fresh water supplied to the drainage
press 46 via the supply line 49 for rinsing the laundry articles,
in order to supplement again the discharged or filtered-off
treatment liquid in order to treat the subsequent batch of laundry
articles in the apparatus.
[0056] In the apparatus of FIG. 2, too, the method, constituting an
independent invention, of measuring during the washing process the
concentration of unspent wash-active substances in the treatment
fluid can be employed. In this method, basically in the same way as
was described in connection with the apparatus of FIG. 1, after the
separation of the spent wash-active substances from the treatment
liquid, the concentration of spent wash-active substances in the
treatment liquid downstream of the filters 52 and/or 57 is
determined continuously (in situ) and a corresponding quantity of
new wash-active substances is added to the treatment liquid in a
regulated manner as a function of a desired concentration of the
wash-active substances. The measurement of the concentration of
unspent wash-active substances in the washing liquid takes place by
means of measuring sensors or measuring probes which were referred
to further above in connection with the exemplary embodiment of
FIG. 1.
LIST OF DESIGNATIONS
[0057] 10 Continuous-flow washing machine [0058] 11 Drainage press
[0059] 12 Axis of rotation [0060] 13 drum [0061] 14 partition
[0062] 15 Flow direction [0063] 16 chamber [0064] 17 Pre-washing
zone [0065] 18 Clear-washing zone [0066] 19 Rinsing zone [0067] 20
Unloading chute [0068] 21 Press basket [0069] 22 Press plunger
[0070] 23 Collecting tank [0071] 24 Outflow line [0072] 25
Pre-filter [0073] 26 filter [0074] 27 Branch point [0075] 28 Return
line [0076] 29 Inflow funnel [0077] 30 Outflow line [0078] 31
Pre-filter [0079] 32 filter [0080] 33 Branch point [0081] 34
Connecting line [0082] 35 Return line [0083] 36 Branch point [0084]
37 Return line [0085] 38 overflow [0086] 39 Collecting tank [0087]
40 Intermediate line [0088] 41 Return line [0089] 42 Return line
[0090] 45 Continuous-flow washing machine [0091] 46 Drainage press
[0092] 47 Pre-washing zone [0093] 48 Clear-washing zone [0094] 49
Supply line [0095] 50 Outflow line [0096] 51 Pre-filter [0097] 52
filter [0098] 53 Branch point [0099] 54 Return line [0100] 55
Outflow line [0101] 56 Pre-filter [0102] 57 filter [0103] 58
Connecting line [0104] 59 Branch point [0105] 60 Outflow line
[0106] 61 Connecting line
* * * * *