EP0726978B1 - Method of dosing detergent product - Google Patents

Method of dosing detergent product Download PDF

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Publication number
EP0726978B1
EP0726978B1 EP94931546A EP94931546A EP0726978B1 EP 0726978 B1 EP0726978 B1 EP 0726978B1 EP 94931546 A EP94931546 A EP 94931546A EP 94931546 A EP94931546 A EP 94931546A EP 0726978 B1 EP0726978 B1 EP 0726978B1
Authority
EP
European Patent Office
Prior art keywords
conductivity
detergent
washing solution
measured
detergent product
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP94931546A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0726978A1 (en
Inventor
Klaas Der Kinderen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Unilever PLC
Unilever NV
Original Assignee
Unilever PLC
Unilever NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Unilever PLC, Unilever NV filed Critical Unilever PLC
Priority to EP94931546A priority Critical patent/EP0726978B1/en
Publication of EP0726978A1 publication Critical patent/EP0726978A1/en
Application granted granted Critical
Publication of EP0726978B1 publication Critical patent/EP0726978B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F34/00—Details of control systems for washing machines, washer-dryers or laundry dryers
    • D06F34/14—Arrangements for detecting or measuring specific parameters
    • D06F34/22—Condition of the washing liquid, e.g. turbidity
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F2103/00—Parameters monitored or detected for the control of domestic laundry washing machines, washer-dryers or laundry dryers
    • D06F2103/20—Washing liquid condition, e.g. turbidity
    • D06F2103/22—Content of detergent or additives
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F2105/00—Systems or parameters controlled or affected by the control systems of washing machines, washer-dryers or laundry dryers
    • D06F2105/42—Detergent or additive supply
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F2105/00—Systems or parameters controlled or affected by the control systems of washing machines, washer-dryers or laundry dryers
    • D06F2105/58—Indications or alarms to the control system or to the user
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F2105/00—Systems or parameters controlled or affected by the control systems of washing machines, washer-dryers or laundry dryers
    • D06F2105/58—Indications or alarms to the control system or to the user
    • D06F2105/60—Audible signals

Definitions

  • the present invention relates to a method of dosing detergent product into a washing solution present in an industrial washing machine, in particular an institutional mechanical ware washing machine.
  • the detergent concentration of the washing solution is usually observed by measuring the electroconductivity of the washing solution between at least two electric electrodes immersed in the washing solution.
  • electroconductivity can be simply defined as the ability of a solution to pass an electrical current.
  • contact to the solution is made by two or more electrodes, and a small alternating current is passed between them. This current is related to the solution conductivity.
  • the conductivity measurement is generally carried out by means of the above-described electrodes and a conductivity amplifier which activates a detergent dosing pump whenever the electroconductivity of the washing solution (and, as a consequence, the detergent concentration) drops below a predetermined threshold value, until the theshold level has been regained. Since the conductivity amplifier may operate up to a high accuracy, it can be ensured under all circumstances that the detergent concentration and washing effect are sufficient, i.e. that the detergent concentration remains constantly above a predetermined level.
  • the electrodes present in the measuring cell are subject to scumming. That is, the electrodes may be coated by a film when they are used to monitor a hard water solution, and, as a result, an acceptable conductivity level may be indicated when in fact the conductivity, and therefore the detergent concentration of the washing solution, is unacceptably high.
  • food soil in the washing solution is likely to cause contamination of the electrodes which may have a detrimental effect on the accuracy of the conductivity measurement.
  • the electrodes have been found to be sensitive to scale build-up resulting in erroneous measurements and, as a consequence, increasing product consumption and operating costs.
  • inductive measuring systems comprising electrodeless conductivity measuring sensors.
  • the type of sensor applied in these inductive systems usually comprises two toroidally wound coils, and when these sensors are immersed in the washing solution to be monitored, said solution provides an electrical coupling between the coils.
  • US-A-4,733,798 discloses an apparatus for controlling the concentration of a washing solution, wherein the conductivity of said solution is measured using an inductive measuring system comprising an electrodeless sensor.
  • an object of the present invention to provide a method for controlling the detergent concentration of a washing solution, whereby a cheap and simple measuring system is applied and which does not have the above drawbacks. It is also an object of the invention to provide a method for controlling the detergent concentration of a washing solution, whereby the detergent consumption is minimised and a constant cleaning performance is achieved.
  • the present invention provides a method of dosing detergent product into a washing solution present in an industrial washing machine, comprising measuring, using a measuring cell including 1 or more electrodes, the conductivity of a washing solution containing water and detergent material, said conductivity being proportional to the detergent concentration of said washing solution, and adding detergent product to the washing solution if the value of the measured conductivity falls below a threshold conductivity value which corresponds to a preset threshold concentration value of said detergent material in said washing solution, said method including the steps of:
  • the method of the invention As a result of the method of the invention, a constant detergent concentration throughout the operating life of the electrodes and at a minimised detergent consumption could be attained. Further advantages of the method of the invention are guaranteed constant cleaning performance using a relatively cheap system including measurement cells containing one or more electrodes, and improved reliability resulting in a reduced number of service calls. Furthermore, the applied system is usually fully automatised. In order to reduce hardware and installation costs, a measuring cell containing only one electrode is preferably applied. In that case, the other "counter" electrode is constituted by the internal wall of the container holding the washing solution to be monitored.
  • this mixing time is generally less than 2 minutes, preferably less than 1 minute.
  • this mixing time is generally less than 1 minute, preferably less than 30 seconds, a mixing time of from 5 to 15 seconds being pre-ferred.
  • the steps according to the present invention are preferably repeated every time the washing machine is filled with clean water.
  • the correct amount of detergent product when filling the washing machine with clean water it is desirable to calculate this amount by determining the internal water volume of the washing machine to be applied.
  • the method of the invention turned out to be particularly suitable for controlling the detergent concentration of washing solutions present in institutional ware washing machines.
  • an alarm function can be included, indicating that the electrodes applied have been contaminated to such extent and that, consequently, their sensitivity has deteriorated so much, that suitable operation of these electrodes is not possible anymore.
  • This alarm function is usually adjustable such that it gives a visual or audible signal when the sensitivity of the electrodes has reduced to a level in the range of 50-70 % of the sensitivity value at the start of their operating life.
  • the specific adjustment of the alarm function depends on the accuracy of the concentration control required: when a higher accuracy is required the alarm will be adjusted to a higher percentage of the initial sensitivity. In other words: in that case, less fouling of the electrodes will be tolerated.
  • figure 1 schematically illustrates a system for carrying out the method of the invention.
  • This figure shows a block diagram of this system, including a conductivity amplifier/controller (1) which is connected to measuring electrodes (3) and (4), one of which may be the internal wall of a container holding a washing solution to be monitored by said system.. These electrodes are immersed in the washing solution at a suitable location. This location is not critical; however, a measuring point positioned close to the detergent feeding point detects the effect of fed detergent product more rapidly.
  • the conductivity amplifier/controller (1) measures the electroconductivity of the washing solution between the measuring electrodes (3) and (4) and generates at its output an activating signal (AKT) when the measured conductivity drops below a preset threshold conductivity value. This preset value is measured during the beginning of the wash cycle, and subsequently stored in the memory (3).
  • AKT activating signal
  • the output of the conductivity amplifier/controller (1) is connected to a control input of a control unit (2) for a detergent dosing pump.
  • This control unit (2) switches on the dosing pump only if the signal AKT is generated.
  • a detergent product having the following composition was tested in an industrial mechanical dishwashing machine containing a measuring cell including a pair of conductivity electrodes: Component Parts by weight Sodium hydroxide (50%) 35.5 Bayhibit AM (1) 3.0 Norasol LMW 45 N (2) 3.0 Demineralised water 58.8 wherein :
  • Example 1 A Indicated detergent product level Clean probe Scaled probe Compensated Uncompensted 1.5 g/l 1.5 1.5 2.2
  • Example 2 B Indicated detergent product level Clean probe Scaled probe Compensated Uncompensted 2.0 g/l 2.0 2.0 2.8
  • Example 3 C Indicated detergent product level Clean probe Scaled probe Compensated Uncompensted 3.5 g/l 3.5 3.5 4.3
EP94931546A 1993-11-02 1994-10-24 Method of dosing detergent product Expired - Lifetime EP0726978B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP94931546A EP0726978B1 (en) 1993-11-02 1994-10-24 Method of dosing detergent product

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
EP93203065 1993-11-02
EP93203065 1993-11-02
PCT/EP1994/003493 WO1995012704A1 (en) 1993-11-02 1994-10-24 Method of dosing detergent product
EP94931546A EP0726978B1 (en) 1993-11-02 1994-10-24 Method of dosing detergent product

Publications (2)

Publication Number Publication Date
EP0726978A1 EP0726978A1 (en) 1996-08-21
EP0726978B1 true EP0726978B1 (en) 1998-09-09

Family

ID=8214155

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94931546A Expired - Lifetime EP0726978B1 (en) 1993-11-02 1994-10-24 Method of dosing detergent product

Country Status (9)

Country Link
EP (1) EP0726978B1 (fi)
AU (1) AU679281B2 (fi)
BR (1) BR9407967A (fi)
CA (1) CA2172723C (fi)
DE (1) DE69413246T2 (fi)
ES (1) ES2123161T3 (fi)
FI (1) FI108866B (fi)
WO (1) WO1995012704A1 (fi)
ZA (1) ZA948468B (fi)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6958693B2 (en) 2002-05-24 2005-10-25 Procter & Gamble Company Sensor device and methods for using same
US7571734B2 (en) 2005-01-20 2009-08-11 General Electric Company Fluid dispensing system for a washing device
US7802335B2 (en) 2007-10-12 2010-09-28 General Electric Company Bulk dispense user adjustable controls
US8056747B2 (en) 2007-10-12 2011-11-15 General Electric Company Removable tank for laundry bulk dispenser system
US8056374B2 (en) 2007-10-12 2011-11-15 General Electric Company Multiple compartments wash additives auto-dispenser in washer or dryer pedestal

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19938010A1 (de) * 1999-08-11 2001-02-15 Bsh Bosch Siemens Hausgeraete Verfahren zur Steuerung, Regelung und Dokumentation eines Reinigungsvorganges
EP1639176B1 (en) * 2003-05-28 2013-07-10 LG Electronics Inc. A control method of a washing machine
WO2004106616A1 (en) * 2003-05-28 2004-12-09 Lg Electronics, Inc. Control method of washing machine
US7581437B2 (en) * 2006-04-07 2009-09-01 Masco Corporation Level sensor for granules in water
US8388695B2 (en) 2008-07-01 2013-03-05 Whirlpool Corporation Apparatus and method for controlling laundering cycle by sensing wash aid concentration
US8266748B2 (en) 2008-07-01 2012-09-18 Whirlpool Corporation Apparatus and method for controlling bulk dispensing of wash aid by sensing wash aid concentration
WO2013087100A1 (en) * 2011-12-14 2013-06-20 Ecolab Usa Inc. Optimized dosing procedure for a washing machine

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3645669A (en) * 1969-02-28 1972-02-29 Gerhard Rausch Method and arrangement for testing the liquid in washing machines
FI773869A (fi) * 1977-12-20 1979-06-21 Asko Upo Oy Foerfarande och anordning foer styrning av skoeljningen i en tvaettmaskin
US4733798A (en) * 1986-02-05 1988-03-29 Ecolab Inc. Method and apparatus for controlling the concentration of a chemical solution
FI80729C (fi) * 1988-04-07 1990-07-10 Vesa Hakulinen Foerfarande och anordning foer dosering av tvaettmedel.
KR920018284A (ko) * 1991-03-29 1992-10-21 가나이 쓰도무 세탁기

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6958693B2 (en) 2002-05-24 2005-10-25 Procter & Gamble Company Sensor device and methods for using same
US7571734B2 (en) 2005-01-20 2009-08-11 General Electric Company Fluid dispensing system for a washing device
US7802335B2 (en) 2007-10-12 2010-09-28 General Electric Company Bulk dispense user adjustable controls
US8056747B2 (en) 2007-10-12 2011-11-15 General Electric Company Removable tank for laundry bulk dispenser system
US8056374B2 (en) 2007-10-12 2011-11-15 General Electric Company Multiple compartments wash additives auto-dispenser in washer or dryer pedestal

Also Published As

Publication number Publication date
AU679281B2 (en) 1997-06-26
DE69413246D1 (de) 1998-10-15
CA2172723A1 (en) 1995-05-11
WO1995012704A1 (en) 1995-05-11
AU8059994A (en) 1995-05-23
FI961837A (fi) 1996-04-30
EP0726978A1 (en) 1996-08-21
ES2123161T3 (es) 1999-01-01
ZA948468B (en) 1996-04-29
FI961837A0 (fi) 1996-04-30
FI108866B (fi) 2002-04-15
BR9407967A (pt) 1996-12-03
DE69413246T2 (de) 1999-02-18
CA2172723C (en) 1997-11-25

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