U.S. patent application number 17/430200 was filed with the patent office on 2022-05-26 for a method for washing laundry in a laundry washing machine and laundry washing machine implementing the method.
This patent application is currently assigned to Electrolux Appliances Aktiebolag. The applicant listed for this patent is Electrolux Appliances Aktiebolag. Invention is credited to Martino Bondi, Andrea Zattin.
Application Number | 20220162790 17/430200 |
Document ID | / |
Family ID | 1000006181243 |
Filed Date | 2022-05-26 |
United States Patent
Application |
20220162790 |
Kind Code |
A1 |
Zattin; Andrea ; et
al. |
May 26, 2022 |
A METHOD FOR WASHING LAUNDRY IN A LAUNDRY WASHING MACHINE AND
LAUNDRY WASHING MACHINE IMPLEMENTING THE METHOD
Abstract
A method for washing laundry in a laundry washing machine
comprising a washing tub external to a washing drum and an
electrical conductivity detecting device. The method comprises the
steps of comparing a first measured conductivity with a first
threshold and comparing a second measured conductivity with a
second threshold for performing one or more actions based on the
result of said first comparison step and/or said second comparison
step. The value of said second threshold is lower than the value of
said first threshold.
Inventors: |
Zattin; Andrea; (Porcia,
IT) ; Bondi; Martino; (Porcia, IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Electrolux Appliances Aktiebolag |
Stockholm |
|
SE |
|
|
Assignee: |
Electrolux Appliances
Aktiebolag
Stockholm
SE
|
Family ID: |
1000006181243 |
Appl. No.: |
17/430200 |
Filed: |
February 27, 2019 |
PCT Filed: |
February 27, 2019 |
PCT NO: |
PCT/EP2019/054857 |
371 Date: |
August 11, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D06F 39/02 20130101;
D06F 2105/52 20200201; D06F 2103/02 20200201; D06F 34/22 20200201;
D06F 2103/20 20200201; D06F 33/38 20200201; D06F 33/36 20200201;
D06F 23/02 20130101 |
International
Class: |
D06F 33/38 20060101
D06F033/38; D06F 34/22 20060101 D06F034/22; D06F 39/02 20060101
D06F039/02; D06F 33/36 20060101 D06F033/36; D06F 23/02 20060101
D06F023/02 |
Claims
1. A method for washing laundry in a laundry washing machine
comprising: a washing drum; a washing tub external to said washing
drum and configured to receive the laundry to be washed; a water
supply system configured to convey water to said washing tub; a
treating agents dispenser configured to supply at least one
treating agent into said washing tub, one of said at least one
treating agent comprising a detergent; a liquid outlet circuit
configured to withdraw liquid from a bottom region of said washing
tub and draining said liquid to an outside of said washing tub; an
electrical conductivity detecting device configured to measure a
conductivity of the liquid flowing therethrough; wherein the method
comprises: performing one or more treating phases for treating said
laundry and performing the washing of said laundry; measuring a
first conductivity of said liquid through said electrical
conductivity detecting device during said one or more treating
phases; comparing said first conductivity with a first threshold;
measuring a second conductivity of said liquid through said
electrical conductivity detecting device during said one or more
treating phases after said first measurement; comparing said second
conductivity with a second threshold; and performing one or more
actions based on the result of said first comparison step and/or
said second comparison step; wherein a value of said second
threshold is lower than a value of said first threshold.
2. The method according to claim 1, wherein: measuring said first
conductivity is performed after introducing water and detergent
into said washing tub and before a draining liquid to the outside
of said washing tub; the method further comprises determining
whether said detergent is a powder detergent or a liquid detergent
by said step of comparing said first conductivity with said first
threshold; and measuring said second conductivity is performed
during a further treating phase.
3. The method according to claim 2, wherein: said further treating
phase is a first rinsing phase; and the method further comprises
determining whether at least one additional rinsing phase is
required by said step of comparing said second conductivity with
said second threshold.
4. The method according to claim 2, further comprising determining
that said detergent is a powder detergent upon determining that
said first measured conductivity is higher than said first
threshold, or determining that said detergent is a liquid detergent
upon determining that said first measured conductivity is not
higher than said first threshold.
5. The method according to claim 3, further comprising determining
that at least one additional rinsing phase is required upon
determining that the second conductivity is higher than said second
threshold.
6. The method according to claim 2, wherein said laundry washing
machine further comprises a turbidity detecting device and the
method further comprises, upon determining that said detergent is
said liquid detergent: determining a soil level of said laundry by
operating said turbidity device to measure a turbidity of said
liquid; and performing at least one soil removal phase before said
first rinsing phase.
7. The method according to claim 6, further comprising determining
that said soil level is above a predetermined value upon
determining that said turbidity is lower than a predetermined
threshold.
8. The method according to claim 6, wherein said at least one soil
removal phase comprises introducing water into said washing tub,
tumbling the laundry and draining liquid to the outside of the
washing tub.
9. The method according to claim 1, wherein: measuring said first
conductivity and comparing said first conductivity with said first
threshold is performed during a first rinsing phase to determine if
at least one additional rinsing phase is required; and comparing
said second measured conductivity with said second threshold is
performed to determine if at least one further additional rinsing
phase is required.
10. The method according to claim 1, further comprising introducing
a waiting period before at least one of measuring said first
conductivity and measuring said second conductivity, the waiting
period being selected to allow said liquid to obtain a
substantially steady state.
11. The method according to claim 1, wherein: comparing said first
conductivity with said first threshold comprises calculating a
difference between a current measured value of conductivity of the
liquid containing the detergent and a conductivity reference value
which refers to the conductivity of clean water, or substantially
clean water, and comparing said difference with said first
threshold; or comparing said second conductivity with said second
threshold comprises calculating a difference between a current
measured value of conductivity of the liquid containing the
detergent and a conductivity reference value which refers to the
conductivity of clean water, or substantially clean water, and
comparing said difference with said second threshold.
12. The method according to claim 11, it further comprising said
conductivity reference value.
13. The method according to claim 1, wherein: comparing said first
conductivity with said first threshold comprises comparing directly
a current measured value of conductivity with said first threshold;
or comparing said second conductivity with said second threshold
comprises comparing directly a current measured value of
conductivity with said second threshold.
14. The method according to claim 3, wherein said rinsing phase
comprises adding clean water to the laundry and draining said
liquid to the outside of the washing tub.
15. A laundry washing machine comprising a washing drum; a washing
tub external to said washing drum and configured to receive the
laundry to be washed; a water supply system configured to convey
water to said washing tub; a treating agents dispenser configured
to supply at least one treating agent into said washing tub, one of
said at least one treating agent comprising a detergent; a liquid
outlet circuit configured to withdraw liquid from a bottom region
of said washing tub and draining said liquid to an outside of said
washing tub; an electrical conductivity detecting device configured
to measure a conductivity of the liquid flowing therethrough; and a
control unit configured to: perform one or more treating phases for
treating said laundry and performing the washing of said laundry;
measure a first conductivity of said liquid through said electrical
conductivity detecting device during said one or more treating
phases; compare said first conductivity with a first threshold;
measure a second conductivity of said liquid through said
electrical conductivity detecting device during said one or more
treating phases after said first measurement; compare said second
conductivity with a second threshold; and perform one or more
actions based on the result of said first comparison step and/or
said second comparison step; wherein a value of said second
threshold is lower than a value of said first threshold.
Description
[0001] The present invention concerns the field of laundry washing
techniques.
[0002] Specifically, the invention relates to a method for washing
laundry in a laundry washing machine equipped with a sensor
unit.
BACKGROUND ART
[0003] Nowadays the use of laundry washing machines, both "simple"
laundry washing machines (i.e. laundry washing machines which can
only wash and rinse laundry) and laundry washing-drying machines
(i.e. laundry washing machines which can also dry laundry), is
widespread.
[0004] In the present description, the term "laundry washing
machine" will refer to both a simple laundry washing machine and a
laundry washing-drying machine.
[0005] Laundry washing machines generally comprise an external
casing, or cabinet, provided with a washing tub which contains a
rotatable perforated washing drum where the laundry is placed. A
loading/unloading door ensures access to the washing drum.
[0006] Laundry washing machines typically comprise a water supply
unit and a treating agents dispenser, preferably equipped with a
drawer, for the introduction of water and washing/rinsing products
(i.e. detergent, softener, rinse conditioner, etc.) into the
washing tub.
[0007] Known laundry washing machines are typically provided with a
water outlet circuit suitable for withdrawing liquid, for example
dirty water, from the bottom of the washing tub to the outside.
Laundry washing machines are also typically provided with one or
more recirculation circuits.
[0008] Water outlet circuit and recirculation circuits are
opportunely operated during washing cycle to wash dirty
clothes.
[0009] Aim of laundry washing machines is to carry out a washing
cycle in order to wash clothes in the best way possible. Laundry
washing machine manufacturers are therefore used to find solutions
to carry out the best washing cycle possible and keeping the
manufacturing costs as low as possible.
[0010] It is an object of the present invention to optimize the
washing cycle in a laundry washing machine and keeping the
manufacturing costs of the machine as low as possible.
[0011] It is another object of the present invention to propose a
laundry washing machine that controls the soil levels on clothes
and performs the proper washing cycle.
[0012] It is a further object of the present invention to propose a
laundry washing machine and a washing cycle that increases cleaning
of the soiled clothes compared to known system.
[0013] It is another object of the present invention to propose a
laundry washing machine that automatically determines the soil
levels on clothes during a washing cycle.
[0014] It is a further object of the present invention to propose a
laundry washing machine and a washing cycle that improves
efficiency of the rinse cycle to remove from the clothes residual
detergent and/or dirty particles.
[0015] It is another object of the present invention to propose a
laundry washing machine that automatically determines the number of
rinsing phases during a rinse cycle.
DISCLOSURE OF INVENTION
[0016] Applicant has found that by providing a laundry washing
machine comprising a washing tub external to a washing drum and an
electrical conductivity detecting device and by performing one or
more actions based on the comparison of values measured through
said device with decreasing thresholds, it is possible to reach the
mentioned objects.
[0017] In a first aspect thereof the present invention relates,
therefore, to a method for washing laundry in a laundry washing
machine comprising: [0018] a washing tub external to a washing drum
suited to receive the laundry to be washed; [0019] a water supply
system suitable to convey water to said washing tub; [0020] a
treating agents dispenser to supply at least one treating agent
into said washing tub, one of said at least one treating agent
comprising a detergent; [0021] a liquid outlet circuit suitable for
withdrawing liquid from a bottom region of said washing tub and
draining said liquid to the outside; [0022] an electrical
conductivity detecting device that measures the conductivity of the
liquid flowing therethrough;
[0023] the method comprising one or more treating phases for
treating said laundry and performing the washing of said
laundry;
[0024] wherein the method comprises the steps of: [0025] performing
a first measurement of conductivity of said liquid through said
electrical conductivity detecting device during said one or more
treating phases; [0026] comparing said first measured conductivity
with a first threshold; [0027] performing a second measurement of
conductivity of said liquid through said electrical conductivity
detecting device during said one or more treating phases after said
first measurement; [0028] comparing said second measured
conductivity with a second threshold; [0029] performing one or more
actions based on the result of said first comparison step and/or
said second comparison step;
[0030] wherein the value of said second threshold is lower than the
value of said first threshold.
[0031] In a preferred embodiment of the invention, said first
measurement of conductivity is carried out after introduction of
water and detergent into the washing is tub and before a draining
step wherein liquid is drained to the outside from the washing tub,
wherein the comparison of said first measured conductivity with a
first threshold is apt to determine if the detergent is a powder
detergent or a liquid detergent and said second measurement of
conductivity is carried out during a further treating phase.
[0032] Preferably, said further treating phase is a first rinsing
phase and wherein said comparison of said second measured
conductivity with a second threshold is apt to determine if at
least one additional rinsing phase is required.
[0033] According to a preferred embodiment of the invention, if
said first measured conductivity is higher than the first threshold
then the detergent is a powder detergent otherwise is a liquid
detergent.
[0034] According to a preferred embodiment of the invention, if
said second measured conductivity is higher than the second
threshold then at least one additional rinsing phase is
required.
[0035] In a preferred embodiment of the invention, the laundry
washing machine further comprises a turbidity detecting device and
if after said first comparison it has determined that said
detergent is a liquid detergent then the method further comprises
the steps of: [0036] determining the soil level of the laundry by
means of measurement of turbidity through said turbidity detecting
device; [0037] performing at least one soil removal phase before
said first rinsing phase.
[0038] Preferably, the soil level is high if said measurement of
turbidity is lower than a predetermined threshold.
[0039] According to a preferred embodiment of the invention, said
at least one soil removal phase comprises introducing water into
the washing tub, tumbling the laundry and draining liquid to the
outside.
[0040] In a preferred embodiment of the invention, the first
measurement of conductivity is carried out during a first rinsing
phase wherein the comparison of said first measured conductivity
with a first threshold is apt to determine if at least one
additional rinsing phase is required and wherein the comparison of
said second measured conductivity with a second threshold is apt to
determine if at least one further additional rinsing phase is
required.
[0041] Preferably, the method comprises a step of introducing a
waiting period before said conductivity measurement so that the
liquid is brought in a substantially steady state for said
measurement.
[0042] Preferably, the method comprises a step of introducing a
waiting period before said turbidity measurement so that the liquid
is brought in a substantially steady state for said
measurement.
[0043] According to a preferred embodiment of the invention, the
step of comparing the first measured conductivity with a first
threshold comprises calculating the difference between the current
measured value of conductivity of the liquid containing the
detergent and a conductivity reference value which refers to the
conductivity of clean water, or substantially clean water, and
comparing the difference with the first threshold and/or the step
of comparing the second measured conductivity with a second
threshold comprises calculating the difference between the current
measured value of conductivity of the liquid containing the
detergent and a conductivity reference value which refers to the
conductivity of clean water, or substantially clean water, and
comparing the difference with the second threshold.
[0044] In a preferred embodiment of the invention, the method
comprises a step of setting the conductivity reference value.
[0045] According to a further preferred embodiment of the
invention, the step of comparing the first measured conductivity
with a first threshold comprises comparing directly the current
measured value of conductivity with the first threshold and/or the
step of comparing the second measured comprises comparing directly
the current measured value of conductivity with the second
threshold.
[0046] Preferably, the rinsing phase comprises adding clean water
to the laundry and draining liquid to the outside.
[0047] Preferably, the rinsing phase further comprises tumbling the
laundry.
[0048] In a preferred embodiment of the invention, the laundry
washing machine comprises a recirculation circuit apt to drain
liquid from the bottom of the washing tub and to re-admit such
liquid into a first region of the washing tub.
[0049] Preferably, the electrical conductivity detecting device is
arranged along the recirculation circuit and/or the turbidity
detecting device is arranged along the recirculation circuit.
[0050] In a second aspect thereof, the present invention concerns a
laundry washing machine suited to implement the method of the
invention described above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0051] Further characteristics and advantages of the present
invention will be highlighted in greater detail in the following
detailed description of some of its preferred embodiments, provided
with reference to the enclosed drawings. In the drawings,
corresponding characteristics and/or components are identified by
the same reference numbers. In particular:
[0052] FIG. 1 shows a perspective view of a laundry washing machine
where a method according to a first preferred embodiment of the
invention is implemented;
[0053] FIG. 2 shows a schematic view of the laundry washing machine
of FIG. 1;
[0054] FIG. 3 is a flow chart of the operations of the method for
washing laundry in the laundry washing machine of FIG. 1 according
to a first preferred embodiment of the invention;
[0055] FIG. 4 shows operations of a processing step of the flow
chart of FIG. 3 according to a first preferred embodiment of the
invention;
[0056] FIG. 5 shows operations of a processing step of the flow
chart of FIG. 3 according to a second preferred embodiment of the
invention;
[0057] FIG. 6 is a flow chart of the operations of the method for
washing laundry in the laundry washing machine of FIG. 1 according
to a second preferred embodiment of the invention;
[0058] FIG. 6A shows operations of a processing step of the flow
chart of FIG. 6 according to a preferred embodiment of the
invention;
[0059] FIG. 7 is a flow chart of the operations of the method for
washing laundry in the laundry washing machine of FIG. 1 according
to a third preferred embodiment of the invention;
[0060] FIG. 8 shows operations of a processing step of the flow
chart of FIG. 7 according to a first preferred embodiment of the
invention;
[0061] FIG. 9 is a flow chart of some operations of the method for
washing laundry in the laundry washing machine of FIG. 1 according
to a further preferred embodiment of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMETS OF THE INVENTION
[0062] The present invention has proved to be particularly
advantageous when applied to laundry washing machines, as described
below. It should in any case be underlined that the present
invention is not limited to laundry washing machines. On the
contrary, the present invention can be conveniently applied to
laundry washing-drying machines (i.e. laundry washing machines
which can also dry laundry).
[0063] With reference to FIGS. 1 and 2 a preferred embodiment of a
laundry washing machine 1, in which a method according to a
preferred embodiment of the invention is implemented, is shown.
[0064] The laundry washing machine 1 preferably comprises an
external casing or cabinet 2, a washing tub 3, a container 4,
preferably a perforated washing drum 4, where the laundry to be
treated can be loaded.
[0065] The washing tub 3 and the washing drum 4 both preferably
have a substantially cylindrical shape.
[0066] The washing tub 3 is preferably connected to the cabinet 2
by means of an elastic bellows, not shown.
[0067] The cabinet 2 is provided with a loading/unloading door 8
which allows access to the washing drum 4.
[0068] The washing drum 4 is advantageously rotated by an electric
motor, not illustrated, which preferably transmits the rotating
motion to the shaft of the washing drum 4, advantageously by means
of a belt/pulley system. In a different embodiment of the
invention, the motor can be directly associated with the shaft of
the washing drum 4.
[0069] The washing drum 4 is advantageously provided with holes
which allow the liquid flowing therethrough. Said holes are
typically and preferably homogeneously distributed on the
cylindrical side wall of the washing drum 4.
[0070] The bottom region 3a of the washing tub 3 preferably
comprises a seat 15, or sump, suitable for receiving a heating
device 10. The heating device 10, when activated, heats the liquid
inside the sump 15.
[0071] In different embodiments, nevertheless, the bottom region of
the washing tub may be configured differently. For example, the
bottom region of the washing tub may not comprise a seat for the
heating device. The heating device may be advantageously placed in
the annular gap between the washing tub and the washing drum.
[0072] Preferably, the laundry washing machine 1 comprises a device
19 suited to detect the liquid level inside the washing tub 3.
[0073] The sensor device 19 preferably comprises a pressure sensor
which senses the pressure in the washing tub 3. From the values
sensed by the sensor device 19 it is possible to determine the
liquid level of the liquid inside the washing tub 3. In another
embodiment, not illustrated, laundry washing machine may preferably
comprise (in addition to or as a replacement of the pressure
sensor) a level sensor (for example mechanical, electro-mechanical,
optical, etc.) adapted to detect the liquid level inside the
washing tub 3.
[0074] A water supply circuit 5 is preferably arranged in the upper
part of the laundry washing machine 1 and is suited to supply water
into the washing tub 3 from an external water supply line E. The
water supply circuit 5 preferably comprises a controlled supply
valve 5a which is properly controlled, opened and closed, during
the washing cycle. The water supply circuit of a laundry washing
machine is well known in the art, and therefore it will not be
described in detail.
[0075] The laundry washing machine 1 advantageously comprises a
treating agents dispenser 14 to supply one or more treating agents
into the washing tub 3 during a washing cycle. Treating agents may
comprise, for example, detergents D, rinse additives, fabric
softeners or fabric conditioners, waterproofing agents, fabric
enhancers, rinse sanitization additives, chlorine-based additives,
etc.
[0076] Preferably, the treating agents dispenser 14 comprises a
removable drawer 6 provided with various compartments suited to be
filled with treating agents.
[0077] In a preferred embodiment, not illustrated, the treating
agents dispenser may comprise a pump suitable to convey one or more
of said agents from the dispenser to the washing tub.
[0078] In the preferred embodiment here illustrated, the water is
supplied into the washing tub 3 from the water supply circuit 5 by
making it flow through the treating agents dispenser 14 and then
through a supply pipe 18.
[0079] In an alternative embodiment of the invention, a further
separate water supply pipe can be provided, which supplies
exclusively clean water into the washing tub from the external
water supply line.
[0080] Laundry washing machine 1 preferably comprises a water
outlet circuit 25 suitable for withdrawing liquid from the bottom
region 3a of the washing tub 3.
[0081] The water outlet circuit 25 preferably comprises a main pipe
17, a draining pump 27 and an outlet pipe 28 ending outside the
cabinet 2.
[0082] The water outlet circuit 25 preferably further comprises a
filtering device 12 arranged between the main pipe 17 and the
draining pump 27. The filtering device 12 is adapted to retain all
the undesirable bodies (for example buttons that have come off the
laundry, coins erroneously introduced into the laundry washing
machine, etc.). The filtering device 12 can preferably be removed,
and then cleaned, through a gate 13 placed advantageously on the
front wall of the cabinet 2 of the laundry washing machine 1, as
illustrated in FIG. 1.
[0083] The main pipe 17 connects the bottom region 3a of the
washing tub 3 to the filtering device 12.
[0084] In a further embodiment, not illustrated, the filtering
device 12 may be provided directly in the washing tub 3, preferably
obtained in a single piece construction with the latter. In this
case, the filtering device 12 is fluidly connected to the outlet of
the washing tub 3, in such a way that water and washing liquid
drained from the washing tub 3 enters the filtering device 12.
[0085] Activation of the draining pump 27 drains the liquid, i.e.
dirty water or water mixed with washing and/or rinsing products,
from the washing tub 3 to the outside.
[0086] The laundry washing machine 1 preferably comprises a
recirculation circuit 30 which is adapted to drain liquid from the
bottom region 3a of the washing tub 3 and to re-admit such a liquid
into a first region 3b of the washing tub 3, as better described
below.
[0087] Preferably, the first region 3b of the washing tub 3
substantially corresponds to an upper region 3b of the washing tub
3. The liquid is preferably re-admitted to the upper region 3b of
the washing tub 3 in order to improve wetting/soaking of the
laundry inside the washing drum 4.
[0088] This action is preferably carried out at the beginning of
the washing cycle when the laundry needs to be completely soaked.
Furthermore, this action is also preferably carried out during
rinsing phases in successive steps of the washing cycle.
[0089] The recirculation circuit 30 preferably comprises a first
duct 33 terminating at said first region 3b, preferably ending at
the bellows. The first duct 33 is preferably provided with a
terminal nozzle 33a.
[0090] The recirculation circuit 30 preferably comprises a
recirculation pump 22 having an outlet 26 connected to the first
duct 33.
[0091] The recirculation pump 22 preferably comprises a pump
chamber, not shown, having an inlet 24 connected to the bottom 3a
of the washing tub 3. Inlet 24 of the recirculation pump 22 is
preferably connected to the bottom 3a of the washing tub 3 through
a suction pipe 32 preferably connected to the filtering device
12.
[0092] The pump chamber of the recirculation pump 22 then
communicates with the outlet 26 for conveying liquid, as said
above, to the first duct 33.
[0093] Laundry washing machine 1 advantageously comprises an
interface unit 16, connected to a control unit, accessible to the
user and by means of which the user may select and set the washing
parameters, like for example a desired washing cycle. Usually,
other parameters can optionally be inserted by the user, for
example the washing temperature, the spinning speed, the load in
terms of weight of the laundry to be washed, etc.
[0094] Based on the parameters acquired by said interface unit 16,
the control unit sets and controls the various parts of the laundry
washing machine 1 in order to carry out the desired washing
cycle.
[0095] According to an advantageous aspect of the invention, the
laundry washing machine 1 preferably comprises a sensor unit
50.
[0096] The sensor unit 50 is preferably arranged along the suction
pipe 32 of the recirculation circuit 30, more preferably at the
inlet 24 of the recirculation pump 22.
[0097] In a preferred embodiment, the sensor unit 50 preferably
comprises a turbidity detecting device 52, in the following simple
indicated as "turbidimeter", and an electrical conductivity
detecting device 54, in the following simple indicated as "EC
meter".
[0098] The turbidimeter 52 preferably comprises an optical
turbidimeter that measures the turbidity of the liquid flowing
through the suction pipe 32. In a preferred embodiment of the
invention the turbidimeter detecting device 52 preferably comprises
a light emitting device and a light receiving device placed in the
suction pipe 32. Output of the turbidimeter 52 gives indication of
the turbidity of the liquid and variations thereof.
[0099] The EC meter 54 preferably measures the conductivity of the
liquid flowing through the suction pipe 32. In a preferred
embodiment of the invention the EC meter 54 preferably comprises a
pair of electrodes in the suction pipe 32 that measures the
electrical conductivity between the electrodes. Output of the EC
meter 54 gives indication of the conductivity of the liquid and
variations thereof.
[0100] A first embodiment of the washing method according to the
invention is described here below with reference to flow chart of
FIGS. 3 and FIG. 4.
[0101] The laundry to be washed is first placed inside the washing
drum 4 (block 100 of FIG. 3).
[0102] The user fills the compailinents of the drawer 6 with the
products needed for treatment of the laundry, for example liquid or
powder detergent D, softener S, etc.
[0103] By operating on the interface unit 16 the user selects the
desired washing cycle (block 110). Furthermore, as said above, in a
preferred embodiment it is possible for the user to insert some
parameters directly by the interface unit 16, for example the value
of the washing temperature, the rotating speed of the washing drum
4 in the spinning phase, the duration of the washing cycle,
etc.
[0104] Once the user has selected the desired washing cycle, the
control unit sets the laundry washing machine 1 so that it starts
the washing cycle.
[0105] In a further embodiment, the selection of the desired
washing cycle (block 110) may be performed before placing the
laundry into the washing drum 4 (block 100).
[0106] In a successive phase (block 120) water and detergent D is
introduced into the washing tub 3, preferably making the water flow
through the detergent compailinent of the treating agents dispenser
14 and then through the supply pipe 18.
[0107] The laundry is preferably tumbled by rotation of the washing
drum 4 and liquid in the washing tub 3 is preferably heated at a
proper temperature by means of the heating device 10 (block 130).
In further preferred embodiments, the heating phase (block 130) may
be omitted.
[0108] In a successive phase the recirculation circuit 30 is
activated (block 150), preferably after a waiting time (block 140),
for example after 10 seconds.
[0109] Wetting/soaking of the laundry inside the washing drum 4 is
thus enhanced.
[0110] The recirculation circuit 30 is activated for a
predetermined period, for example 14 seconds (block 150), by
switching on the recirculation pump 22.
[0111] The recirculation circuit 30 is then deactivated (block
160), by switching off the recirculation pump 22.
[0112] As described above, wetting/soaking of the laundry inside
the washing drum 4 is preferably obtained through activation of the
recirculation circuit 30.
[0113] In different embodiments, nevertheless, wetting/soaking of
the laundry inside the washing drum 4 may be obtained differently.
For example, wetting/soaking of the laundry inside the washing drum
4 may be obtained by introducing a proper quantity of water inside
the washing tub 3 so that the water enters the washing drum 4 and
wet/soak the laundry. In such a case, the laundry washing machine
may be even not equipped with any recirculation circuit.
[0114] According to an aspect of the invention, the type of
detergent used to wash the laundry, i.e. liquid or powder, is
determined (block 172). The type of detergent is preferably
determined on the base of the values of the conductivity of the
liquid used to wet/soak the laundry, or wash liquor, measured by
the EC meter 54.
[0115] The liquid conductivity is preferably measured by means of
the EC meter 54 along the suction pipe 32.
[0116] According to the invention, the current measured value of
conductivity is used to determine if the detergent is a liquid
detergent or a powder detergent (comparing block 172).
[0117] In the preferred embodiments of the invention hereinafter
described, the comparison is not carried out using directly the
current measured value of conductivity Cc but rather using the
parameter .DELTA.C=Cc-C0, wherein C0 is a water conductivity
reference value which refers to the conductivity of the clean
water, also indicate as the parameter ZeroConductivity. The value
of the parameter ZeroConductivity C0 is preferably set in a phase
of the washing cycle wherein the liquid inside the washing tub 3
may be considered clean, or substantially clean, as better
described later.
[0118] Throughout the description, therefore, the parameter
.DELTA.C=Cc-C0 is always preferably used to carry out comparisons
with predetermined thresholds. In different preferred embodiments,
nevertheless, current measured value of conductivity Cc could be
directly used for the comparison with predetermined ad hoc
thresholds.
[0119] Preferably, in block 172 the difference .DELTA.C between the
current measured value of conductivity Cc and the ZeroConductivity
value C0, i.e. .DELTA.C=Cc-C0, is compared with a predetermined
first threshold .DELTA.C1 to determine if the detergent is a liquid
detergent or a powder detergent.
[0120] Preferably, if .DELTA.C is not higher than the predetermined
first threshold .DELTA.C (output "No" of block 172), for example
not higher than .DELTA.C1=500 .mu.S/cm, the detergent is considered
to be a liquid detergent and a parameter LIQUID is preferably set
to 1 (block 174).
[0121] The parameter LIQUID is set to 0 before the comparing block
172. Preferably, the parameter LIQUID is automatically set to 0 at
the beginning of the washing cycle.
[0122] Preferably, if .DELTA.C is higher than the predetermined
first threshold .DELTA.C1 (output "Yes" of block 172), for example
higher than 500 .mu.S/cm, the detergent is considered to be a
powder detergent and a parameter POWDER is preferably set to 1
(block 176).
[0123] The parameter POWDER is set to 0 before the comparing block
172. Preferably, the parameter POWDER is automatically set to 0 at
the beginning of the washing cycle.
[0124] Once the determination of the type of detergent has been
completed, a washing maintenance phase is preferably performed
(block 200).
[0125] In this phase the laundry is preferably tumbled by rotation
of the washing drum 4 for a predetermined maintenance time so that
the laundry is subject to mechanical action and the detergent D has
time to react with the dirty laundry.
[0126] At the end of the maintenance phase (block 200), the wash
liquor is drained to the outside by activating the draining pump 27
of the water outlet circuit 25 (block 210).
[0127] In a successive step of the method, the washing cycle
preferably comprises a spinning phase to extract wash liquor from
the laundry (block 240) and a draining phase for draining the wash
liquor to the outside by activating the draining pump 27 of the
water outlet circuit 25 (block 250).
[0128] The washing cycle then preferably proceeds with further
phases, globally indicated with block 260, to terminate the washing
cycle. Final phases (block 260) preferably comprise a rinse cycle
(block 400 or block 400') and a final spinning phase (block
900).
[0129] A rinse cycle (block 400) according a first preferred
embodiment of the invention is shown and described with reference
to the flow chart of FIG. 4.
[0130] As known, the rinse cycle preferably comprises one or more
rinsing phases wherein clean water is added to the laundry and then
drained to the outside to remove from the laundry the residual
detergent D and/or dirty particles.
[0131] According to an aspect of the invention, the number of
rinsing phases after a first mandatory rinsing phase is evaluated
automatically according to the values detected by the EC meter 54.
Furthermore, evaluation of the values detected by the EC meter 54
depends on the detergent type previously determined through the EC
meter 54 or, in other words, the values detected by the EC meter 54
are treated differently if the detergent is a liquid detergent or a
powder detergent.
[0132] The rinse cycle (block 400) starts with a water loading
(block 410) for the first mandatory rinsing phase wherein water is
introduced into the washing tub 3.
[0133] In a successive step it is checked the type of detergent
used (block 430).
[0134] Check of the detergent type is carried out by controlling
the value of the parameter POWDER previously determined. Namely, if
the parameter POWDER is 1 then the detergent is a powder detergent
(output "Yes" of block 430) otherwise the detergent is a liquid
detergent (output "No" of block 430).
[0135] In a different embodiment, check of the detergent type may
be analogously carried out by controlling the value of the
parameter LIQUID previously determined.
[0136] If the detergent is a powder detergent (output "Yes" of
block 430), the current measured value of conductivity Cc is
compared with the value of ZeroConductivity C0. Preferably, in
block 440 the difference .DELTA.C=Cc-C0 between the current
measured value of conductivity Cc and the ZeroConductivity value C0
is compared with a predetermined second threshold .DELTA.C11, for
example .DELTA.C11=300 .mu.S/cm. According to an aspect of the
invention, the second threshold .DELTA.C11 is set lower than the
first threshold .DELTA.C1.
[0137] Preferably, if .DELTA.C is higher than the predetermined
second threshold .DELTA.C11 (output "Yes" of block 440) then the
amount of residual powder detergent D still present in the liquid
is considered too high. For this reason, and according to an aspect
of the invention, it is considered that the washing cycle will need
an additional rinsing phase. At this purpose, the value of a
parameter RinseCount is incremented by 1 (block 450).
[0138] Throughout the description, the value of the parameter
RinseCount indicates the number of an additional rinsing phases
needed.
[0139] The parameter RinseCount is set to 0 before the comparing
block 440. Preferably, the parameter RinseCount is automatically
set to 0 at the beginning of the washing cycle.
[0140] If .DELTA.C is not higher than the predetermined second
threshold .DELTA.C11 (output "No" of block 440) then the amount of
residual powder detergent D still present in the liquid is
considered acceptable. At this purpose, the value of the parameter
RinseCount remains unchanged and therefore it is considered that
the washing cycle will not need any additional rinsing phase.
[0141] In order to enhance measurement of the conductivity through
the EC meter 54 in a substantially steady state of the liquid, a
waiting period (block 420) is preferably introduced before
measurement, for example 30 seconds.
[0142] Analogously, if the detergent is a liquid detergent (output
"No" of block 430), the current measured value of conductivity Cc
is compared with the value of ZeroConductivity C0. Preferably, in
block 460 the difference .DELTA.C=Cc-C0 between the current
measured value of conductivity Cc and the ZeroConductivity value C0
is compared with a predetermined third threshold .DELTA.C21, for
example .DELTA.C21=20 .mu.S/cm. According to an aspect of the
invention, the third threshold .DELTA.C21 is set lower than the
first threshold .DELTA.C1.
[0143] Preferably, if .DELTA.C is higher than the predetermined
third threshold .DELTA.C21 (output "Yes" of block 460) then the
amount of residual liquid detergent D still present in the liquid
is considered too high. For this reason, and according to an aspect
of the invention, it is considered that the washing cycle will need
an additional rinsing phase. At this purpose, the value of the
parameter RinseCount is incremented by 1 (block 470).
[0144] If .DELTA.C is not higher than the predetermined third
threshold .DELTA.C21 (output "No" of block 460) then the amount of
residual liquid detergent D still present in the liquid is
considered acceptable. At this purpose, the value of the parameter
RinseCount remains unchanged and therefore it is considered that
the washing cycle will not need any additional rinsing phase.
[0145] It has to be noted that the values of second and third
thresholds .DELTA.C11, .DELTA.C21 are opportunely chosen taking
into account the fact that the conductivity of the wash liquor
comprising powder detergent is higher than the conductivity of the
wash liquor is comprising liquid detergent. Therefore, the second
threshold .DELTA.C11 is higher than the third threshold
.DELTA.C21.
[0146] In a successive step of the rinse cycle it is checked the
value of the parameter RinseCount (block 500).
[0147] If the parameter RinseCount is 0 (output "No" of block 500)
then it is considered that the first mandatory rinsing phase is
enough, and the rinse cycle (block 400) can terminate with a
draining phase (block 530) wherein the liquid is drained to the
outside by activating the draining pump 27.
[0148] Preferably, before the draining phase (block 530) the
parameter ZeroConductivity C0 is set with the current measured
value of conductivity Cc (block 520). In fact, at this point of the
washing cycle, the liquid inside the washing tub 3 may be
considered clean, or substantially clean. The parameter
ZeroConductivity C0 set herein is then used in the next washing
cycle.
[0149] Here again, preferably, in order to enhance measurement of
the conductivity through the EC meter 54 in a substantially steady
state of the liquid, a waiting period (block 510) is preferably
introduced before measurement, for example 30 seconds.
[0150] Conversely, if the parameter RinseCount is higher than 0
(output "Yes" of block 500) then it is considered that an
additional (second) rinsing phase is necessary.
[0151] In a successive step, a draining phase is carried out (block
540) wherein the liquid is drained to the outside by activating the
draining pump 27. This draining phase (block 540) coincides with
the end of the first mandatory rinsing phase.
[0152] It follows a water loading (block 550) for starting the
additional (second) rinsing phase wherein water is introduced into
the washing tub 3.
[0153] An optional intermediate spinning phase is preferably
carried out (block 560).
[0154] The value of the parameter RinseCount is finally decremented
by 1 (block 570).
[0155] The method then back to the step of checking the RinseCount
value (block 500).
[0156] Therefore, according to the preferred embodiment of the
rinse cycle here described with reference to flow chart FIG. 4
(block 400), the value detected by the EC meter 54, block 440 for
powder detergent or block 460 for liquid detergent, is used to
eventually perform an additional (second) rinsing phase further to
the first mandatory rinsing phase by incrementing by 1 the
RinseCount parameter.
[0157] In a further preferred embodiment, the method could provide
for a greater number of rinsing phases after the first one,
preferably by incrementing the RinseCount parameter by a respective
value. For example, the RinseCount parameter can be incremented by
3 in block 450 or 470 and the rinsing steps from 540 to 570 are
carried out three times accordingly.
[0158] A rinse cycle (block 400') according a second preferred
embodiment of the invention is shown and described with reference
to flow chart of FIG. 5.
[0159] In the flow chart of FIG. 5, blocks having the same
reference numbers of the flow chart of FIG. 4 identify the same
features as previously described.
[0160] This embodiment differs from that previously described with
reference to FIG. 4 in that the rinse cycle comprises two mandatory
rinsing phases, instead of one.
[0161] The number of additional rinsing phases after the two
mandatory rinsing phases is then evaluated automatically according
to the values detected by the EC meter 54. Preferably, the values
detected by the EC meter 54 are treated differently if the
detergent is a liquid detergent or a powder detergent.
[0162] The rinse cycle (block 400') starts with a water loading
(block 410) for the first mandatory rinsing phase wherein water is
introduced into the washing tub 3.
[0163] In a successive step it is checked the type of detergent
used (block 430).
[0164] Check of the detergent type is carried out by controlling
the value of the parameter POWDER previously determined. Namely, if
the parameter POWDER is 1 then the detergent is a powder detergent
(output "Yes" of block 430) otherwise the detergent is a liquid
detergent (output "No" of block 430).
[0165] In a different embodiment, check of the detergent type may
be analogously carried out by controlling the value of the
parameter LIQUID previously determined.
[0166] If the detergent is a powder detergent (output "Yes" of
block 430), the current measured value of conductivity Cc is
compared with the value of ZeroConductivity C0. Preferably, in
block 440 the difference .DELTA.C=Cc-C0 between the current
measured value of conductivity Cc and the ZeroConductivity value C0
is compared with a predetermined second threshold .DELTA.C11, for
example .DELTA.C11=300 .mu.S/cm. As said above, and according to an
aspect of the present invention, the second threshold .DELTA.C11 is
set lower than the first threshold .DELTA.C1.
[0167] Preferably, if .DELTA.C is higher than the predetermined
second threshold .DELTA.C11 (output "Yes" of block 440) then the
amount of residual powder detergent D still present in the liquid
is considered too high. For this reason, and according to an aspect
of the invention, it is considered that the washing cycle will need
at least one additional rinsing phase. At this purpose, the value
of a parameter RinseCount is incremented by 1 (block 450).
[0168] The parameter RinseCount is set to 0 before the comparing
block 440. Preferably, the parameter RinseCount is automatically
set to 0 at the beginning of the washing cycle.
[0169] If .DELTA.C is not higher than the predetermined second
threshold .DELTA.C11 (output "No" of block 440) then the amount of
residual powder detergent D still present in the liquid is
considered not too high. At this purpose, the value of the
parameter RinseCount remains unchanged.
[0170] In order to enhance measurement of the conductivity through
the EC meter 54 in a substantially steady state of the liquid, a
waiting period (block 420) is preferably introduced before
measurement, for example 30 seconds.
[0171] Analogously, if the detergent is a liquid detergent (output
"No" of block 430), the current measured value of conductivity Cc
is compared with the value of ZeroConductivity C0. Preferably, in
block 460 the difference .DELTA.C=Cc-C0 between the current
measured value of conductivity Cc and the ZeroConductivity value C0
is compared with a predetermined third threshold .DELTA.C21, for
example .DELTA.C21=20 .mu.S/cm. As said above, and according to an
aspect of the present invention, the third threshold .DELTA.C21 is
set lower than the first threshold .DELTA.C1.
[0172] Preferably, if .DELTA.C is higher than the predetermined
third threshold .DELTA.C21 (output "Yes" of block 460) then the
amount of residual liquid detergent D still present in the liquid
is considered too high. For this reason, and according to an aspect
of the invention, it is considered that the washing cycle will need
at least one additional rinsing phase. At this purpose, the value
of the parameter RinseCount is incremented by 1 (block 470).
[0173] If .DELTA.C is not higher than the predetermined third
threshold .DELTA.C21 (output "No" of block 460) then the amount of
residual liquid detergent D still present in the liquid is
considered not too high. At this purpose, the value of the
parameter RinseCount remains unchanged.
[0174] It has to be noted that the values of second and third
thresholds .DELTA.C11, .DELTA.C21 are opportunely chosen taking
into account the fact that the conductivity of the wash liquor
comprising powder detergent is higher than the conductivity of the
wash liquor comprising liquid detergent. Therefore, the second
threshold .DELTA.C11 is higher than the third threshold
.DELTA.C21.
[0175] In a successive step, a draining phase is carried out (block
472) wherein the liquid is drained to the outside by activating the
draining pump 27. This draining phase (block 472) coincides with
the end of the first mandatory rinsing phase.
[0176] An optional intermediate spinning phase is then preferably
carried out (block 474).
[0177] It follows a water loading (block 476) for starting the
second mandatory rinsing phase wherein water is introduced into the
washing tub 3.
[0178] In a successive step of the rinse cycle it is checked again
the type of detergent used (block 480).
[0179] If the detergent is a powder detergent (output "Yes" of
block 480), the current measured value of conductivity Cc is
compared with the value of ZeroConductivity C0. Preferably, in
block 482 the difference .DELTA.C=Cc-C0 between the current
measured value of conductivity Cc and the ZeroConductivity value C0
is compared with a predetermined fourth threshold .DELTA.C12, for
example .DELTA.C12=40 .mu.S/cm.
[0180] According to an aspect of the present invention, the fourth
threshold .DELTA.C12 is set lower than the second threshold
.DELTA.C11.
[0181] Preferably, if .DELTA.C is higher than the predetermined
fourth threshold .DELTA.C12 (output "Yes" of block 482) then the
amount of residual powder detergent D present in the liquid is
still considered too high. For this reason, and according to an
aspect of the invention, it is considered that the washing cycle
will need at least one additional rinsing phase. At this purpose,
the value of the parameter RinseCount is incremented by 1 (block
484).
[0182] If .DELTA.C is not higher than the predetermined fourth
threshold .DELTA.C12 (output "No" of block 482) then the amount of
residual powder detergent D still present in the liquid is
considered not too high. At this purpose, the value of the
parameter RinseCount remains unchanged.
[0183] In a further preferred embodiment, instead, the value of the
parameter RinseCount is set to 0 indicating that no additional
rinsing phases are needed.
[0184] In order to enhance measurement of the conductivity through
the EC meter 54 in a substantially steady state of the liquid, a
waiting period (block 478) is preferably introduced before
measurement, for example 30 seconds.
[0185] Analogously, if the detergent is a liquid detergent (output
"No" of block 480), the current measured value of conductivity Cc
is compared with the value of ZeroConductivity C0. Preferably, in
block 486 the difference .DELTA.C=Cc-C0 between the current
measured value of conductivity Cc and the ZeroConductivity value C0
is compared with a predetermined fifth threshold .DELTA.C22, for
example .DELTA.C22=5 .mu.S/cm. According to an aspect of the
present invention, the fifth threshold .DELTA.C22 is set lower than
the third threshold .DELTA.C21.
[0186] Preferably, if .DELTA.C is higher than the predetermined
fifth threshold .DELTA.C22 (output "Yes" of block 486) then the
amount of residual liquid detergent D still present in the is
liquid is considered too high. For this reason, and according to an
aspect of the invention, it is considered that the washing cycle
will need at least one additional rinsing phase. At this purpose,
the value of the parameter RinseCount is incremented by 1 (block
488).
[0187] If .DELTA.C is not higher than the predetermined fifth
threshold .DELTA.C22 (output "No" of block 486) then the amount of
residual liquid detergent D still present in the liquid is
considered acceptable. At this purpose, the value of the parameter
RinseCount remains unchanged.
[0188] In a further preferred embodiment, instead, the value of the
parameter RinseCount is set to 0 indicating that no additional
rinsing phases are needed.
[0189] In a successive step of the rinse cycle it is checked the
value of the parameter RinseCount (block 500).
[0190] If the parameter RinseCount is 0 (output "No" of block 500)
then it is considered that the two mandatory rinsing phases are
enough, and the rinse cycle (block 400') can terminate with a
draining phase (block 530) wherein the liquid is drained to the
outside by activating the draining pump 27.
[0191] Preferably, before the draining phase (block 530) the
parameter ZeroConductivity C0 is set with the current measured
value of conductivity Cc (block 520). The parameter
ZeroConductivity C0 set herein is then used in the next washing
cycle.
[0192] Here again, preferably, in order to enhance measurement of
the conductivity through the EC meter 54 in a substantially steady
state of the liquid, a waiting period (block 510) is preferably
introduced before measurement, for example 30 seconds.
[0193] Conversely, if the parameter RinseCount is higher than 0
(output "Yes" of block 500) then it is considered that a further
rinsing phase is necessary.
[0194] In a successive step, a draining phase is carried out (block
540) wherein the liquid is drained to the outside by activating the
draining pump 27. This draining phase (block 540) coincides with
the end of the second mandatory rinsing phase.
[0195] It follows a water loading (block 550) for starting the
additional (third) rinsing phase wherein water is introduced into
the washing tub 3.
[0196] An optional intermediate spinning phase is preferably
carried out (block 560).
[0197] The value of the parameter RinseCount is finally decremented
by 1 (block 570).
[0198] The method then back to the step of checking the RinseCount
value (block 500).
[0199] Therefore, according to the preferred embodiment of the
rinse cycle here described with reference to flow chart FIG. 5
(block 400'), the values detected by the EC meter 54, blocks 440
and 482 for powder detergent or blocks 460 and 486 for liquid
detergent, are used to eventually perform additional third and/or a
fourth rinsing phases further to the two mandatory rinsing phases
by incrementing the RinseCount parameter.
[0200] A further embodiment of the washing cycle according to the
invention is described with reference to flow charts of FIGS. 6 and
6A.
[0201] The method according to the flow chart of FIG. 6 differs
from the method previously described with reference to FIGS. 3 in
that it comprises a soil level determination step and, in case, it
performs a corresponding soil removal phase, as better explained
below.
[0202] Preferably, determination of the soil level and respective
removal phase is carried out only if it is determined that the
detergent is a liquid detergent. Conversely, if it is determined
that the detergent is a power detergent, the soil level is not
considered.
[0203] In the flow chart of FIG. 6, blocks having the same
reference numbers of the flow chart of FIG. 3 identify the same
features as previously described.
[0204] The method therefore preferably comprises the above
described steps of: [0205] placing laundry inside the washing drum
4 (block 100); [0206] filling the compartments of the drawer 6 with
the products needed for treatment of the laundry, for example
liquid or powder detergent D, softener S, etc.; [0207] selecting
the desired washing cycle (block 110); [0208] introducing water and
detergent D into the washing tub 3 (block 120); [0209] optionally
heating the wash liquor in the washing tub 3 (block 130); [0210]
waiting some seconds (block 140); [0211] activating the
recirculation circuit 30 (block 150) for a predetermined period and
deactivating the recirculation circuit 30 (block 160); [0212]
waiting some seconds so that wash liquor is brought to a
substantially steady state (block 170).
[0213] The type of detergent used to wash the laundry, i.e. liquid
or powder, is then determined (block 172).
[0214] The current measured value of conductivity Cc is compared
with the ZeroConductivity value C0.
[0215] Preferably, in block 172 the difference .DELTA.C between the
current measured value of conductivity Cc and the ZeroConductivity
value C0, i.e. .DELTA.C=Cc-C0, is compared with a predetermined
first threshold .DELTA.C1 to determine if the detergent is a liquid
detergent or a powder detergent.
[0216] Preferably, if .DELTA.C is not higher than the predetermined
first threshold .DELTA.C (output "No" of block 172), for example
not higher than .DELTA.C1=500 .mu.S/cm, the detergent is considered
to be a liquid detergent and a parameter LIQUID is preferably set
to 1 (block 174).
[0217] The parameter LIQUID is set to 0 before the comparing block
172. Preferably, the parameter LIQUID is automatically set to 0 at
the beginning of the washing cycle.
[0218] According to an aspect of the invention, the turbidity of
wash liquor used to wet/soak the laundry, i.e. water and liquid
detergent D, is detected (block 180), preferably by means of the
turbidimeter 52. The liquid turbidity is preferably detected by
means of the turbidimeter 52 along the suction pipe 32. Measurement
of turbidity through the turbidimeter 52 is preferably carried in a
substantially steady state of the wash liquor thanks to the waiting
period previously introduced (block 170).
[0219] According to the invention, the measured turbidity is
compared with a predetermined threshold T1 (comparing block 180) to
determine if the laundry is excessively soiled and to set a
corresponding soil level parameter "SOIL" (block 190).
[0220] Preferably, if the measured turbidity is lower than the
predetermined threshold T1 (block 180), then the laundry is
considered excessively soiled and the parameter SOIL is set to 1
(block 190).
[0221] More preferably, if the measured turbidity is lower than 40%
with respect to the value measured through the clean water, then
the laundry is considered excessively soiled and the parameter SOIL
is set to 1 (block 190). Here, the predetermined threshold T1 is
preferably defined as a percentage with respect to the ideal
situation in which totally clean water flows through the
turbidimeter 52. In a preferred embodiment of the invention,
therefore, the turbidimeter 52 is advantageously calibrated in
advance by the manufacturer so that its measurement for totally
clean water corresponds to value 100. Any measured value lower than
100 gives an indication of turbidity, the lower is the measured
value the higher is the turbidity.
[0222] It has to be noted that the parameter SOIL is set to 0
before the comparing block 180. Preferably, the parameter SOIL is
automatically set to 0 at the beginning of the washing cycle.
[0223] The predetermined threshold T1 is preferably determined by
experimental trials.
[0224] Once the soil level determination of the wash liquor has
been completed, a washing maintenance phase is preferably performed
(block 200).
[0225] In this phase the laundry is preferably tumbled by rotation
of the washing drum 4 for a predetermined maintenance time so that
the laundry is subject to mechanical action and the detergent D has
time to react with the dirty laundry.
[0226] Preferably, if .DELTA.C is higher than the predetermined
first threshold .DELTA.C1 (output "Yes" of block 172), for example
higher than 500 .mu.S/cm, the detergent is considered to be a
powder detergent and a parameter POWDER is preferably set to 1
(block 176).
[0227] The parameter POWDER is set to 0 before the comparing block
172. Preferably, the parameter POWDER is automatically set to 0 at
the beginning of the washing cycle.
[0228] Once the parameter POWDER is set to 1 (block 176), a washing
maintenance phase is preferably performed (block 200).
[0229] It has to be noted that the soil level is not determined in
case the detergent is a powder detergent. In fact, in case a powder
detergent is used, the turbidity of the liquid is negatively
affected by the powder detergent itself and therefore the turbidity
measurement may not be actually the indication of the soil level of
wash liquor.
[0230] At the end of the maintenance phase (block 200), the wash
liquor is drained to the outside by activating the draining pump 27
of the water outlet circuit 25 (block 210).
[0231] After the draining phase (block 210) and according to an
aspect of the invention, the method preferably performs a soil
removal phase (block 230) if the laundry has been previously
considered excessively soiled.
[0232] In particular, if the parameter SOIL is equal to 1 (exit
branch "Yes" of block 220), the soil removal phase is performed
(block 230).
[0233] The soil removal phase (block 230) according to a preferred
embodiment of the invention is shown in FIG. 6A.
[0234] The soil removal phase (block 230) preferably comprises a
water load step (block 310) wherein clean water is introduced into
the washing tub 3 by the water supply circuit 5, a washing movement
phase (block 320) wherein the laundry is preferably tumbled by
rotation of the washing drum 4 and subject to mechanical action and
a draining phase (block 330) wherein the wash liquor is preferably
drained to the outside by activating the draining pump 27 of the
water outlet circuit 25.
[0235] In different preferred embodiments, the soil removal phase
may comprise a plurality of washing movement phases and/or a
plurality of draining phases.
[0236] According to an advantageous aspect of the invention, the
soil removal phase (block 230) increases cleaning of the soiled
laundry. Furthermore, and according to a further advantageous
aspect of the invention, the soil removal phase (block 230) is
performed after the high-level soil of the wash liquor has been
automatically determined through the turbidimeter 52 (block
180).
[0237] In a successive step of the method, the washing cycle
preferably comprises a spinning phase to extract wash liquor from
the laundry (block 240) and a draining phase for draining the wash
liquor to the outside by activating the draining pump 27 of the
water outlet circuit 25 (block 250).
[0238] The washing cycle then preferably proceeds with further
phases (block 260) to terminate the washing cycle. Such phases
preferably comprise a rinse cycle (block 400 or 400') and a final
spinning phase (block 900), ad described above.
[0239] A further embodiment of the washing cycle according to the
invention is described with reference to flow charts of FIGS. 7 and
8.
[0240] The method according to the flow chart of FIG. 7 refers to a
preferred standard washing cycle that can be carried out in the
laundry washing machine of FIGS. 1 and 2.
[0241] According to an advantageous aspect of this preferred
embodiment, the method comprises a new rinse cycle (block 400'')
better described with reference to FIG. 8.
[0242] The method according to this preferred embodiment is
correctly carried out if the detergent used and introduced into the
drawer is exclusively a power detergent.
[0243] In a further preferred embodiment, as better explained
later, the method can be easily modified to be correctly carried
out if the detergent used and introduced into the drawer is
exclusively a liquid detergent.
[0244] In the flow chart of FIG. 7, blocks having the same
reference numbers of the flow chart of FIG. 3 identify the same
features as previously described.
[0245] The method therefore preferably comprises the above
described steps of: [0246] placing laundry inside the washing drum
4 (block 100); [0247] filling the compartments of the drawer 6 with
the products needed for treatment of the laundry, namely powder
detergent D and other products, for example softener S, etc.,
[0248] selecting the desired washing cycle (block 110); [0249]
introducing water and powder detergent D into the washing tub 3
(block 120); [0250] optionally heating the wash liquor in the
washing tub 3 (block 130); [0251] waiting some seconds (block 140);
[0252] activating the recirculation circuit 30 (block 150) for a
predetermined period and deactivating the recirculation circuit 30
(block 160); [0253] performing a washing maintenance phase (block
200); [0254] performing a draining phase (block 210) wherein the
wash liquor is drained to the outside by activating the draining
pump 27 of the water outlet circuit 25; [0255] performing a
spinning phase to extract wash liquor from the laundry (block 240)
and a draining phase for draining the wash liquor to the outside by
activating the draining pump 27 of the water outlet circuit 25
(block 250).
[0256] The washing cycle then preferably proceeds with final phases
(block 260) preferably comprising a rinse cycle (block 400'') and a
final spinning phase (block 900).
[0257] A rinse cycle (block 400'') according a preferred embodiment
of the invention is shown and described with reference to flow
chart of FIG. 8.
[0258] In the flow chart of FIG. 8, blocks having the same
reference numbers of the flow chart of FIG. 5 identify the same
features as previously described.
[0259] This embodiment differs from that previously described with
reference to FIG. 5 in that the step of checking the type of
detergent used is omitted. As said above it assumed that detergent
used and introduced into the drawer 6 is exclusively a power
detergent D.
[0260] The rinse cycle (block 400'') starts with a water loading
(block 410) for the first mandatory rinsing phase wherein water is
introduced into the washing tub 3.
[0261] In a successive step, the difference .DELTA.C=Cc-C0 between
the current measured value of conductivity Cc and the
ZeroConductivity value C0 is compared with a predetermined first
threshold .DELTA.C31 (block 440), for example .DELTA.C31=300
.mu.S/cm.
[0262] Preferably, if .DELTA.C is higher than the predetermined
first threshold .DELTA.C31 (output "Yes" of block 440) then the
amount of residual powder detergent D still present in the liquid
is considered too high. For this reason, and according to an aspect
of the invention, it is considered that the washing cycle will need
at least one additional rinsing phase. At this purpose, the value
of a parameter RinseCount is incremented by 1 (block 450).
[0263] The parameter RinseCount is set to 0 before the comparing
block 440. Preferably, the parameter RinseCount is automatically
set to 0 at the beginning of the washing cycle.
[0264] If .DELTA.C is not higher than the predetermined first
threshold .DELTA.C31 (output "No" of block 440) then the amount of
residual powder detergent D still present in the liquid is
considered not too high. At this purpose, the value of the
parameter RinseCount remains unchanged.
[0265] In order to enhance measurement of the conductivity through
the EC meter 54 in a substantially steady state of the liquid, a
waiting period (block 420) is preferably introduced before
measurement, for example 30 seconds.
[0266] In a successive step, a draining phase is carried out (block
472) wherein the liquid is drained to the outside by activating the
draining pump 27. This draining phase (block 472) coincides with
the end of the first mandatory rinsing phase.
[0267] An optional intermediate spinning phase is then preferably
carried out (block 474).
[0268] It follows a water loading (block 476) for starting the
second mandatory rinsing phase wherein water is introduced into the
washing tub 3.
[0269] In a successive step, the current measured value of
conductivity Cc is compared with the value of ZeroConductivity C0.
Preferably, in block 482 the difference .DELTA.C=Cc-C0 between the
current measured value of conductivity Cc and the ZeroConductivity
value C0 is compared with a predetermined second threshold
.DELTA.C32, for example .DELTA.C32=40 .mu.S/cm.
[0270] According to an aspect of the present invention, the second
threshold .DELTA.C32 is set lower than the first threshold
.DELTA.C31.
[0271] Preferably, if .DELTA.C is higher than the predetermined
second threshold .DELTA.C32 (output "Yes" of block 482) then the
amount of residual powder detergent D present in the liquid is
still considered too high. For this reason, and according to an
aspect of the invention, it is considered that the washing cycle
will need at least one additional rinsing phase. At this purpose,
the value of the parameter RinseCount is incremented by 1 (block
484).
[0272] If .DELTA.C is not higher than the predetermined second
threshold .DELTA.C32 (output "No" of block 482) then the amount of
residual powder detergent D still present in the liquid is
considered acceptable. At this purpose, the value of the parameter
RinseCount remains unchanged.
[0273] In a further preferred embodiment, instead, the value of the
parameter RinseCount is set to 0 indicating that no additional
rinsing phases are needed.
[0274] In order to enhance measurement of the conductivity through
the EC meter 54 in a substantially steady state of the liquid, a
waiting period (block 478) is preferably introduced before
measurement, for example 30 seconds.
[0275] In a successive step of the rinse cycle it is checked the
value of the parameter RinseCount (block 500).
[0276] If the parameter RinseCount is 0 (output "No" of block 500)
then it is considered that the two mandatory rinsing phases are
enough, and the rinse cycle (block 400'') can terminate with a
draining phase (block 530) wherein the liquid is drained to the
outside by activating the draining pump 27.
[0277] Preferably, before the draining phase (block 530) the
parameter ZeroConductivity C0 is set with the current measured
value of conductivity Cc (block 520). The parameter
ZeroConductivity C0 set herein is then used in the next washing
cycle.
[0278] Here again, preferably, in order to enhance measurement of
the conductivity through the EC meter 54 in a substantially steady
state of the liquid, a waiting period (block 510) is preferably
introduced before measurement, for example 30 seconds.
[0279] Conversely, if the parameter RinseCount is higher than 0
(output "Yes" of block 500) then it is considered that a further
rinsing phase is necessary.
[0280] In a successive step, a draining phase is carried out (block
540) wherein the liquid is drained to the outside by activating the
draining pump 27. This draining phase (block 540) coincides with
the end of the second mandatory rinsing phase.
[0281] It follows a water loading (block 550) for starting the
additional (third) rinsing phase wherein water is introduced into
the washing tub 3.
[0282] An optional intermediate spinning phase is preferably
carried out (block 560).
[0283] The value of the parameter RinseCount is finally decremented
by 1 (block 570).
[0284] The method then back to the step of checking the RinseCount
value (block 500).
[0285] According to the preferred embodiment of the rinse cycle
here described with reference to flow chart FIG. 8 (block 400''),
the values detected by the EC meter 54, blocks 440 and 482, are
used to eventually perform additional third and/or a fourth rinsing
phases further to the two mandatory rinsing phases by incrementing
the RinseCount parameter.
[0286] As explained above, the method according to flow charts of
FIGS. 7 and 8 is correctly carried out if the detergent used and
introduced into the drawer (block 120) is exclusively a power
detergent D.
[0287] Accordingly, the values of the first threshold .DELTA.C31
and of the second threshold .DELTA.C32 are preferably set as 300
.mu.S/cm and 40 .mu.S/cm, respectively.
[0288] In a further preferred embodiment, the method may be
correctly carried out if the detergent used and introduced into the
drawer is exclusively a liquid detergent, instead of powder
detergent.
[0289] In such a case, the flow chart of FIG. 8 may be adapted by
setting the values of the first threshold .DELTA.C31 and of the
second threshold .DELTA.C32 with proper values, for example
.DELTA.C31=20 .mu.S/cm and .DELTA.C32=5 .mu.S/cm, respectively.
[0290] FIG. 9 shows a flow chart of a further preferred embodiment
of the washing cycle according to the invention. In particular, the
preferred embodiment here illustrated and described allows setting
of the parameter ZeroConductivity C0 since the very beginning of
the washing cycle. Setting of the parameter ZeroConductivity C0
according to the preferred embodiment preferably comprises
preliminary phases carried out the first time the washing machine
performs a washing cycle. Preferably, said preliminary phases are
carried out at the first washing cycle after installation of the
laundry washing machine 1.
[0291] As said above, the value of the parameter ZeroConductivity
C0 is preferably set when the liquid inside the washing tub 3 may
be considered clean, or substantially clean.
[0292] In case of first-time installation, the parameter
ZeroConductivity C0 is previously set to 0 by the manufacture.
[0293] When the washing cycle starts (block 1000), a first amount
of clean water is introduced into the washing tub 3 (block
1010).
[0294] If the parameter ZeroConductivity C0 is equal to 0 (output
"Yes" of block 1020) it is determined that the parameter
ZeroConductivity C0 need to be initialized.
[0295] The parameter ZeroConductivity C0 is therefore set with the
current measured value of conductivity Cc (block 1040).
[0296] Preferably, in order to enhance measurement of the
conductivity through the EC meter 54 in a substantially steady
state of the liquid, a waiting period (block 1030) is preferably
introduced before measurement, for example 50 seconds.
[0297] The washing cycle then will proceed with the remaining
phases, for example phases described with reference to flow chart
of FIG. 3 or 6 or 7: a laundry loading (block 100), a washing cycle
selection (block 110), introduction of detergent and water (block
120), etc.
[0298] Conversely, if the parameter ZeroConductivity C0 is
different from 0 (output "No" of block 1020) then it is not
actually the case of the first washing cycle after installation of
the laundry washing machine but it is assumed that the parameter
ZeroConductivity C0 has been already set in a previous washing
cycle, for example according to phase of block 520 of FIG. 4 or 5
or 8.
[0299] It has thus been shown that the present invention allows all
the set objects to be achieved. In particular, the method according
to the invention optimizes the washing cycle in a laundry washing
machine.
[0300] In the preferred embodiment of the laundry washing machine
above described where the method according to the invention is
implemented, the sensor unit 50 has been arranged along the
recirculation circuit 30, more preferably at the inlet 24 of the
recirculation pump 22. Furthermore, the sensor unit 50 is placed
downstream of the filtering device 12 so that the liquid is at
least partially cleaned.
[0301] Nevertheless, in further preferred embodiments, the sensor
unit 50 may be arranged in different places, like for example in
the sump 15 or at the bottom 3a of the is washing tub 3, etc.
[0302] In the preferred embodiment of the laundry washing machine
above described where the method according to the invention is
implemented, the recirculation circuit 30 is adapted to drain
liquid from the bottom region 3a of the washing tub 3 and to
re-admit such a liquid into an upper region 3b of the washing tub
3.
[0303] Nevertheless, in further preferred embodiments, the
recirculation circuit may be preferably adapted to drain liquid
from the bottom region of the washing tub and to re-admit such a
liquid into another region of the washing tub, for example the same
bottom region of the washing tub.
[0304] Furthermore, as already explained in the description, the
laundry washing machine may be even not equipped with any
recirculation circuit.
[0305] While the present invention has been described with
reference to the particular embodiments shown in the figures, it
should be noted that the present invention is not limited to the
specific embodiments illustrated and described herein; on the
contrary, further variants of the embodiments described herein fall
within the scope of the present invention, which is defined in the
claims.
* * * * *