EP0726978A1 - Method of dosing detergent product - Google Patents
Method of dosing detergent productInfo
- Publication number
- EP0726978A1 EP0726978A1 EP94931546A EP94931546A EP0726978A1 EP 0726978 A1 EP0726978 A1 EP 0726978A1 EP 94931546 A EP94931546 A EP 94931546A EP 94931546 A EP94931546 A EP 94931546A EP 0726978 A1 EP0726978 A1 EP 0726978A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- detergent
- measured
- washing solution
- conductivity
- 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.)
- Granted
Links
- 239000003599 detergent Substances 0.000 title claims abstract description 67
- 238000000034 method Methods 0.000 title claims abstract description 28
- 238000005406 washing Methods 0.000 claims abstract description 66
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000000463 material Substances 0.000 claims abstract description 5
- 230000035945 sensitivity Effects 0.000 claims description 6
- 241000331231 Amorphocerini gen. n. 1 DAD-2008 Species 0.000 claims 1
- 230000006870 function Effects 0.000 abstract description 5
- 239000000523 sample Substances 0.000 description 11
- 238000004851 dishwashing Methods 0.000 description 6
- 230000001939 inductive effect Effects 0.000 description 6
- 238000005259 measurement Methods 0.000 description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- GPXCJKUXBIGASD-UHFFFAOYSA-N 1-phosphonobutane-1,2,4-tricarboxylic acid Chemical compound OC(=O)CCC(C(O)=O)C(C(O)=O)P(O)(O)=O GPXCJKUXBIGASD-UHFFFAOYSA-N 0.000 description 1
- 229920002125 Sokalan® Polymers 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000008233 hard water Substances 0.000 description 1
- 239000004584 polyacrylic acid Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 159000000000 sodium salts Chemical class 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
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 deter- gent product into a washing solution present in an in ⁇ dustrial 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 cir- cumstances that the detergent concentration and washing effect are sufficient, i.e. that the detergent con ⁇ centration remains constantly above a predeterminede level. However, it has been observed that the detergent con ⁇ centration in prior art washing systems usually exceeds considerably the threshold level yielding complete clean ⁇ ness. This over-dosage of detergent product may amount to tens of percents, thus causing considerable extra operating costs.
- 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 accep ⁇ table 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 con ⁇ tamination 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 conduc ⁇ tivity of said solution is measured using an inductive measuring system comprising an electrodeless sensor.
- the present invention provides a method of dosing detergent product into a washing solution present in an industrial washing machine, comprising measuring, from a washing solution containing water and detergent material, a proper ⁇ ty which is proportional to the detergent concentration of said washing solution, and adding detergent product to the washing solution if the value of the measured property corresponds to a detergent concentration below a preset threshold value, whereby the measured property is the electroconductivity of the washing solution, said property being measured using a measuring cell including 1 or more electrodes, characterised by 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. Further ⁇ more, 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.
- the mixing time before the conduc ⁇ tivity is measured is as short as possible.
- 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 il ⁇ lustrates 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 conduc ⁇ tivity amplifier/controller (1) measures the electroconduc- tivity of the washing solution between the measuring electrodes (3) and (4) and generates at its output an ac ⁇ tivating signal (AKT) when the measured conductivity drops below a preset threshold value.
- AKT ac ⁇ tivating signal
- This preset value is measured during the beginning of the wash cycle, and subse- quently stored in the memory (3) .
- 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.
- Bayhibit AM Phosphono-1,2,4-butane-tricarboxylic acid
- Norasol LMW 45 N Sodium salt of polyacrylic acid, ex Norsohaas.
Landscapes
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Washing And Drying Of Tableware (AREA)
- Detergent Compositions (AREA)
- Control Of Washing Machine And Dryer (AREA)
Abstract
A method is provided of dosing detergent product into a washing solution present in an industrial washing machine, comprising measuring, from a washing solution containing water and detergent material, a property which is proportional to the detergent concentration of said washing solution, and adding detergent product to the washing solution if the value of the measured property corresponds to a detergent concentration below a preset threshold value, whereby the measured property is the electroconductivity of the washing solution, said property being measured using a measuring cell including one or more electrodes (3, 4) characterised by the steps of: (a) dosing, during filling of the washing machine with clean water, a sufficient amount of detergent product so as to attain present threshold value, followed by mixing of said dosed tetergent product with the water; (b) measuring the conductivity of the thus obtained wash liquor, after a mixing time of less than 2 minutes; and (c) storing said measured conductivity and the detergent concentration value corresponding thereto, as the preset threshold values, in the memory (3) of a controller (1), which is attached to the measuring cell and controls the dosing of detergent product as a function of the conductivity measured.
Description
METHOD OF DOSING DETERGENT PRODUCT
FIELD OF THE INVENTION
The present invention relates to a method of dosing deter- gent product into a washing solution present in an in¬ dustrial washing machine, in particular an institutional mechanical ware washing machine.
BACKGROUND OF THE INVENTION In prior art washing systems, 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. In this respect, electroconductivity can be simply defined as the ability of a solution to pass an electrical current. In a conventional conductivity sensor 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 cir- cumstances that the detergent concentration and washing effect are sufficient, i.e. that the detergent con¬ centration remains constantly above a predeterminede level.
However, it has been observed that the detergent con¬ centration in prior art washing systems usually exceeds considerably the threshold level yielding complete clean¬ ness. This over-dosage of detergent product may amount to tens of percents, thus causing considerable extra operating costs.
In GB-A-2,217,050, this problem related to the usually applied overdosage of detergent material, has been recog- nised. Consequently, this document discloses a method for reducing this overdosage, wherein the detergent product is periodically added in small dosages and allowed to mix with and dissolve in the washing solution for a pre-determined period of time after each dosage, thus ensuring that no undissolved detergent material affecting the measuring result is left in the washing solution at the start of the next dosing period, and that the conductivity then measured very accurately corresponds to the actual detergent con¬ centration of the washing solution.
It is known that systems for controlling the detergent concentration in a washing solution, in which a pair of electrodes immersed in the washing solution are used, pos¬ sess shortcomings. For example, 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 accep¬ table conductivity level may be indicated when in fact the conductivity, and therefore the detergent concentration of the washing solution, is unacceptably high. Furthermore, food soil in the washing solution is likely to cause con¬ tamination of the electrodes which may have a detrimental effect on the accuracy of the conductivity measurement. Finally, 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.
Since the mentioned conditions leading to erroneous measurements (i.e. scumming, contamination and scale build¬ up) occur at the interface between washing solution and electrode, so-called inductive measuring systems comprising electrodeless conductivity measuring sensors have been developed. 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 conduc¬ tivity of said solution is measured using an inductive measuring system comprising an electrodeless sensor.
However, the commercially available inductive measuring systems suitable for monitoring the electroconductivity and thus the detergent concentration of the washing soluton, are up till now extremely expensive. Furthermore, con¬ tamination of the coils with food soil can prevent the prolonged establishment of a homogeneous distribution of the detergent product in the washing solution, particularly near the coils. Other drawbacks of inductive measuring systems are the following:
(i) in view of the inductive measuring technique, a certain minimum distance between the coils and the internal wall of the container for holding the washing solution to be monitored, is required. So, this measuring technique is not applicable in containers or pipes of reduced size; (ii) because the signal produced in the coils is weak, the length of the cables between coils and conductivity amplifier needs to be restricted.
It is, therefore, an object of the present invention to provide a method for controlling the detergent con¬ centration 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 con¬ centration of a washing solution, whereby the detergent consumption is minimised and a constant cleaning perfor¬ mance is achieved.
It has now surprisingly been found that these and other objects can be accomplished by carrying out the method of the present invention, whereby the conductivity of the washing solution to be monitored is measured with a measuring cell containing electrodes.
DEFINITION OF THE INVENTION
The present invention provides a method of dosing detergent product into a washing solution present in an industrial washing machine, comprising measuring, from a washing solution containing water and detergent material, a proper¬ ty which is proportional to the detergent concentration of said washing solution, and adding detergent product to the washing solution if the value of the measured property corresponds to a detergent concentration below a preset threshold value, whereby the measured property is the electroconductivity of the washing solution, said property being measured using a measuring cell including 1 or more electrodes, characterised by the steps of:
(a) dosing, during filling of the washing machine with clean water, a sufficient amount of detergent product so as to attain said preset threshhold value, followed by mixing of said dosed detergent product with the water;
(b) measuring the conductivity of the thus obtained wash liquor, after a mixing time of less than 2 minutes; and
(c) storing said measured conductivity and the detergent concentration value corresponding thereto, as the preset threshold values, in the memory of a controller, which is attached to the measuring cell and controlls the dosing of detergent product as a function of the conductivity measured.
DETAILED DESCRIPTION OF THE INVENTION
As a result of the method according to the present inven¬ tion, the problems related to the use of electrodes are largely overcome. This is achieved by measuring the conduc¬ tivity of the wash solution in the beginning of a washing cycle for obtaining a preset threshold value for the deter¬ gent concentration of the solution.
As a consequence of the early measurement of the conduc¬ tivity, contamination, scale buildup and scumming of the electrodes which has accumulated during the previous washing cycles, cannot negatively influence the detergent concentration control of the washing solution. This ac¬ cumulation of fouling of the electrodes may stretch out over a period of months depending on the frequency of service intervals of the installation concerned.
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. Further¬ more, 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.
It is desirable that the mixing time before the conduc¬ tivity is measured, is as short as possible. When the method of the invention is applied for monitoring the detergent concentration in washing solutions in multi- tank ware washing machines, this mixing time is generally less than 2 minutes, preferably less than 1 minute. Alternatively, when the method of the invention is applied for monitoring the detergent concentration in washing solutions in single tank ware washing machines, 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.
For obtaining optimal detergent consumption, the steps according to the present invention are preferably repeated every time the washing machine is filled with clean water. For dosing 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.
In the method of the invention, 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.
The invention will now be further explained by way of the following preferred embodiment and with reference to the accompanying drawing in which figure 1 schematically il¬ lustrates 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 conduc¬ tivity amplifier/controller (1) measures the electroconduc- tivity of the washing solution between the measuring electrodes (3) and (4) and generates at its output an ac¬ tivating signal (AKT) when the measured conductivity drops below a preset threshold value. This preset value is measured during the beginning of the wash cycle, and subse- quently stored in the memory (3) .
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.
The invention is illustrated by way of the following non- limiting Examples.
Examples 1, 2, 3. Comparative Examples A, B, C A detergent product having the following composition was tested in an industrial mechanical dishwashing machine containing a measuring cell including a pair of conduc¬ tivity 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 :
(1) Bayhibit AM : Phosphono-1,2,4-butane-tricarboxylic acid
(50%) , ex Bayer
(2) Norasol LMW 45 N : Sodium salt of polyacrylic acid, ex Norsohaas.
First, three mechanical dishwashing cycles were carried out with a clean conductivity probe at various dosing levels, to obtain an indicated detergent product level of respec- tively 1.5 g/1, 2.0 g/1, and 3.5 g/1. Subsequently, at each of these dosing levels two mechanical dishwashing cycles were carried out with a scaled conductivity probe: one cycle whereby a pre-set threshold value according to the method of the present invention was used, and a second comparative cycle whereby said pre-set threshold value was
not used. In other words: during the mechanical dishwashing cycles according to the invention the scaling effect of the probe was compensated, whereas said compensation was not carried out during the comparative cycles. During all dishwashing cycles, the actual detergent level in the wash liquor was measured.
The following actual product concentrations in the mechanical dishwashing liquors (in g/1) were found:
Example
Indicated detergent Clean Scaled probe product level probe Compensated Uncompensted
1.5 g/1 1.5 1.5 2.2
Example 2 B
Indicated detergent Clean Scaled probe product level probe Compensated Uncompensted
2.0 g/1 2.0 2.0 2.8
Example
Indicated detergent Clean Scaled probe product level probe Compensated Uncompensted
3.5 g/1 3.5 3.5 4.3
It can be noted that at all dosing levels tested more detergent product was actually applied than indicated, when uncompensated scaled conductivity probes were used. On the other hand, the actual detergent product concentration in the wash liquor was found to be equal to the indicated product level when compensated scaled probes were applied.
Claims
1. A method of dosing detergent product into a washing solution present in an industrial washing machine, comprising measuring, from a washing solution containing water and detergent material, a property which is propor¬ tional to the detergent concentration of said washing solution, and adding detergent product to the washing solution if the value of the measured property corresponds to a detergent concentration below a preset threshhold value, whereby the measured property is the electroconduc¬ tivity of the washing solution, said property being measured using a measuring cell including one or more electrodes, characterised by the steps of:
(a) dosing, during filling of the washing machine with clean water, a sufficient amount of detergent product so as to attain said preset threshhold value, followed by mixing of said dosed detergent product with the water; (b) measuring the conductivity of the thus obtained wash liquor, after a mixing time of less than 2 minute; and (c) storing said measured conductivity and the detergent concentration value corresponding thereto, as the preset threshold values, in the memory of a controller, which is attached to the measuring cell and controlls the dosing of detergent product as a function of the conductivity measured.
2. The method according to claim 1, wherein the measuring cell contains 2 electrodes.
3. The method according to claim 1 or 2, wherein the con¬ ductivity of the wash liquor is measured after a mixing time of less than 1 minute.
4. The method according to any of the preceding claims, wherein the steps mentioned in claim 1 are repeated whenever the washing machine is filled with clean water.
5. The method according to any of the preceding claims, wherein the amount of detergent product to be dosed for obtaining the preset threshhold concentration value is calculated by determining the internal water volume of the washing machine.
6. The method according to any of the preceding claims, whereby said method is carried out in an industrial ware washing machine.
7. The method according to any of the preceding claims, wherein an alarm element is applied which indicates when the sensitivity of the electrodes has reduced to a level in the range of 50-70% of the sensitivity at the start of their oparting life.
**********
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 true EP0726978A1 (en) | 1996-08-21 |
| EP0726978B1 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 (en) |
| AU (1) | AU679281B2 (en) |
| BR (1) | BR9407967A (en) |
| CA (1) | CA2172723C (en) |
| DE (1) | DE69413246T2 (en) |
| ES (1) | ES2123161T3 (en) |
| FI (1) | FI108866B (en) |
| WO (1) | WO1995012704A1 (en) |
| ZA (1) | ZA948468B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| US8388695B2 (en) | 2008-07-01 | 2013-03-05 | Whirlpool Corporation | Apparatus and method for controlling laundering cycle by sensing wash aid concentration |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19938010A1 (en) * | 1999-08-11 | 2001-02-15 | Bsh Bosch Siemens Hausgeraete | Process for controlling, regulating and documenting a cleaning process |
| US6958693B2 (en) | 2002-05-24 | 2005-10-25 | Procter & Gamble Company | Sensor device and methods for using same |
| BRPI0410718B1 (en) * | 2003-05-28 | 2012-04-17 | washing machine and its control method. | |
| BRPI0410728A (en) | 2003-05-28 | 2006-06-20 | Lg Electronics Inc | washing machine control method |
| US7571734B2 (en) | 2005-01-20 | 2009-08-11 | General Electric Company | Fluid dispensing system for a washing device |
| US7581437B2 (en) * | 2006-04-07 | 2009-09-01 | Masco Corporation | Level sensor for granules in water |
| US7802335B2 (en) | 2007-10-12 | 2010-09-28 | General Electric Company | Bulk dispense user adjustable controls |
| US8056374B2 (en) | 2007-10-12 | 2011-11-15 | General Electric Company | Multiple compartments wash additives auto-dispenser in washer or dryer pedestal |
| US8056747B2 (en) | 2007-10-12 | 2011-11-15 | General Electric Company | Removable tank for laundry bulk dispenser system |
| EP3396052B1 (en) * | 2011-12-14 | 2023-12-27 | Ecolab USA Inc. | Optimized dishwashing machine and its use |
Family Cites Families (5)
| 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 (en) * | 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 (en) * | 1988-04-07 | 1990-07-10 | Vesa Hakulinen | FOERFARANDE OCH ANORDNING FOER DOSERING AV TVAETTMEDEL. |
| KR920018284A (en) * | 1991-03-29 | 1992-10-21 | 가나이 쓰도무 | washer |
-
1994
- 1994-10-24 AU AU80599/94A patent/AU679281B2/en not_active Expired
- 1994-10-24 ES ES94931546T patent/ES2123161T3/en not_active Expired - Lifetime
- 1994-10-24 DE DE69413246T patent/DE69413246T2/en not_active Expired - Lifetime
- 1994-10-24 BR BR9407967A patent/BR9407967A/en not_active IP Right Cessation
- 1994-10-24 WO PCT/EP1994/003493 patent/WO1995012704A1/en active IP Right Grant
- 1994-10-24 CA CA002172723A patent/CA2172723C/en not_active Expired - Lifetime
- 1994-10-24 EP EP94931546A patent/EP0726978B1/en not_active Expired - Lifetime
- 1994-10-27 ZA ZA948468A patent/ZA948468B/en unknown
-
1996
- 1996-04-30 FI FI961837A patent/FI108866B/en not_active IP Right Cessation
Non-Patent Citations (1)
| Title |
|---|
| See references of WO9512704A1 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| US8388695B2 (en) | 2008-07-01 | 2013-03-05 | Whirlpool Corporation | Apparatus and method for controlling laundering cycle by sensing wash aid concentration |
| US10066331B2 (en) | 2008-07-01 | 2018-09-04 | Whirlpool Corporation | Apparatus and method for controlling laundering cycle by sensing wash aid concentration |
Also Published As
| Publication number | Publication date |
|---|---|
| BR9407967A (en) | 1996-12-03 |
| WO1995012704A1 (en) | 1995-05-11 |
| AU8059994A (en) | 1995-05-23 |
| AU679281B2 (en) | 1997-06-26 |
| FI108866B (en) | 2002-04-15 |
| DE69413246T2 (en) | 1999-02-18 |
| ES2123161T3 (en) | 1999-01-01 |
| EP0726978B1 (en) | 1998-09-09 |
| FI961837A0 (en) | 1996-04-30 |
| FI961837A (en) | 1996-04-30 |
| ZA948468B (en) | 1996-04-29 |
| CA2172723A1 (en) | 1995-05-11 |
| CA2172723C (en) | 1997-11-25 |
| DE69413246D1 (en) | 1998-10-15 |
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