EP0008819B1 - Improvement to dishwashing machine operation - Google Patents
Improvement to dishwashing machine operation Download PDFInfo
- Publication number
- EP0008819B1 EP0008819B1 EP19790200419 EP79200419A EP0008819B1 EP 0008819 B1 EP0008819 B1 EP 0008819B1 EP 19790200419 EP19790200419 EP 19790200419 EP 79200419 A EP79200419 A EP 79200419A EP 0008819 B1 EP0008819 B1 EP 0008819B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- water
- anion
- exchange resin
- dishwashing machine
- exchange
- 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
Links
- 238000004851 dishwashing Methods 0.000 title claims description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
- 239000003957 anion exchange resin Substances 0.000 claims description 12
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 claims description 9
- 239000003729 cation exchange resin Substances 0.000 claims description 9
- 238000005406 washing Methods 0.000 claims description 7
- -1 bicarbonate anions Chemical class 0.000 claims description 6
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 4
- 150000001768 cations Chemical class 0.000 claims description 3
- 239000003456 ion exchange resin Substances 0.000 claims description 3
- 229920003303 ion-exchange polymer Polymers 0.000 claims description 3
- 238000000034 method Methods 0.000 claims description 3
- 239000011780 sodium chloride Substances 0.000 claims description 2
- 239000000047 product Substances 0.000 description 14
- 239000004115 Sodium Silicate Substances 0.000 description 8
- 239000003599 detergent Substances 0.000 description 8
- 235000019795 sodium metasilicate Nutrition 0.000 description 8
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 8
- 229910052911 sodium silicate Inorganic materials 0.000 description 8
- 239000011347 resin Substances 0.000 description 6
- 229920005989 resin Polymers 0.000 description 6
- 230000008929 regeneration Effects 0.000 description 5
- 238000011069 regeneration method Methods 0.000 description 5
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 4
- 238000005349 anion exchange Methods 0.000 description 4
- 238000005342 ion exchange Methods 0.000 description 4
- 108091006522 Anion exchangers Proteins 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000001172 regenerating effect Effects 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- HWGNBUXHKFFFIH-UHFFFAOYSA-I pentasodium;[oxido(phosphonatooxy)phosphoryl] phosphate Chemical compound [Na+].[Na+].[Na+].[Na+].[Na+].[O-]P([O-])(=O)OP([O-])(=O)OP([O-])([O-])=O HWGNBUXHKFFFIH-UHFFFAOYSA-I 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 229910052938 sodium sulfate Inorganic materials 0.000 description 2
- 235000011152 sodium sulphate Nutrition 0.000 description 2
- 235000019832 sodium triphosphate Nutrition 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000008399 tap water Substances 0.000 description 2
- 235000020679 tap water Nutrition 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 241000543379 Cobaea scandens Species 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 239000007844 bleaching agent Substances 0.000 description 1
- 238000005341 cation exchange Methods 0.000 description 1
- 229940023913 cation exchange resins Drugs 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 235000017168 chlorine Nutrition 0.000 description 1
- 239000013065 commercial product Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000002736 nonionic surfactant Substances 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
Images
Classifications
-
- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
- A47L15/00—Washing or rinsing machines for crockery or tableware
- A47L15/42—Details
- A47L15/4229—Water softening arrangements
Definitions
- the invention relates to a method for improving the dishwashing machine operation.
- the present invention is not concerned with the basic mechanics of such washing machines, but proposes to improve the dishwashing machine operation in that it allows the use of detergents with a lower content of alkaline ingredients.
- the operation of a dishwashing machine is based on the combination of three distinct actions, viz.
- Current detergent powders or liquids for use in dishwashing machines are generally highly alkaline products comprising essentially nonionic surfactant, sodium triphosphate, sodium metasilicate and chlorine bleach.
- All dishwashing machines are provided with a water-softening device, operating on the principle of removing the water-hardness cations, viz Ca2+ and Mg 2+ ions, from tap water by ion-exchange, using a cation-exchange resin which is capable of exchanging Ca2+ and Mg 2+ ions.
- a water-softening device operating on the principle of removing the water-hardness cations, viz Ca2+ and Mg 2+ ions, from tap water by ion-exchange, using a cation-exchange resin which is capable of exchanging Ca2+ and Mg 2+ ions.
- Such a device generally comprises a column containing a cation-exchange resin, through which the intake water is passed before entering the machine.
- Many natural waters also contain bicarbonate anions (HC03 which form the so-called temporary hardness of the water. These ions are not removed by the water-softening device containing a cation-exchange resin.
- the invention now provides a method for improving the dishwashing machine operation in that it enables the use of detergent products of lower alkaline content, comprising the removal of both the water-hardness cations as well as the bicarbonate anions from the intake water entering the machine during the washing programme by passing the intake water through a cation exchange resin and an anion exchange resin, characterised in that both ion exchange resins are regenerated with sodium chloride.
- the dishwashing machine is operated with an additional ion-exchange device in the intake water line comprising a column containing an anion-exchange resin for removing said bicarbonate anions from the water in conjunction with a water-softening device.
- This device can be installed either as a separate device connected in series with the water-softening device either before or after it, or in parallel therewith, or it can form an integral part of a combined water-softening and decarbonating system.
- the ion-exchange resin column contains a mixture of cation-exchange resin and anion-exchange resin.
- the water entering the dishwashing machine will be substantially free from Ca2+, Mg 2+ and HC0 3 - ions.
- anion-exchange resins which can be used in the present invention are known in the art and various types are commercially available, ranging from the very basic types to the slightly acid types. "Lewatit"@ anion-exchange resins, supplied by the Bayer Company, Leverkusen, Germany, are typical examples of readily available commercial products.
- anion-exchange resins are those which can be regenerated with a solution of NaCI, such resins will be regeneratable with the same regeneration salt as that normally used for regenerating the water-softening resin. Regeneration may then take place simultaneously for both water-softening resin and the anion-exchange resin without any special measures.
- An example of such resin is the commercial product "Lewatit M 600", supplied by the Bayer Company.
- FIG. 1 An example of a combined ion-exchange device according to the invention for installing in a dishwashing machine is shown schematically in the attached Figure 1.
- the figure shows a column (1) containing a mixture of anion- and cation-exchange resins and a container (2) for the regenerating salt.
- water is taken in via line (3) and passes through the ion-exchange column, where it is softened and decarbonated at the same time before entering the machine at point (4).
- all or part of the water stream can be passed through the regenerating salt vessel (2) via line (5).
- a column containing the anion-exchange resin "Lewatit M 600" was installed in the water intake line of a Flandria dishwashing machine type R12 before the water-softening device.
- Fig. 2 is a graph showing the evolution of HC0 3 - concentration in a dishwashing machine with and without an anion-exchanger column containing "Lewatit M 600", which was regenerated after each cycle with NaCI.
- the upper curve shows HC0 3 - concentration in the machine without an anion exchange device.
- the lower curve shows HC0 3 - concentration in the machine provided with an anion-exchange device.
- the machine was operated according to a programme including the regeneration of the resins, using the following detergent products.
Landscapes
- Detergent Compositions (AREA)
- Treatment Of Water By Ion Exchange (AREA)
Description
- The invention relates to a method for improving the dishwashing machine operation.
- Industrial and household dishwashing machines of various types and designs are known in the art. The present invention is not concerned with the basic mechanics of such washing machines, but proposes to improve the dishwashing machine operation in that it allows the use of detergents with a lower content of alkaline ingredients.
- The operation of a dishwashing machine is based on the combination of three distinct actions, viz.
- 1) mechanical action exerted by water-spray,
- 2) thermal action exerted by heating,
- 3) physico-chemical action exerted by the added detergent.
- Current detergent powders or liquids for use in dishwashing machines are generally highly alkaline products comprising essentially nonionic surfactant, sodium triphosphate, sodium metasilicate and chlorine bleach.
- Lowering the alkaline content of such detergent products for machine-dishwashing without affecting their physico-chemical performance could be an important step towards milder products and environmental consequences.
- All dishwashing machines are provided with a water-softening device, operating on the principle of removing the water-hardness cations, viz Ca2+ and Mg2+ ions, from tap water by ion-exchange, using a cation-exchange resin which is capable of exchanging Ca2+ and Mg2+ ions. Such a device generally comprises a column containing a cation-exchange resin, through which the intake water is passed before entering the machine. Many natural waters also contain bicarbonate anions (HC03 which form the so-called temporary hardness of the water. These ions are not removed by the water-softening device containing a cation-exchange resin.
- It is known from GB-A-1233488 to treat water, which is used in dishwashing machines, with a cation exchange resin in the hydrogen form and an anion exchange resin in the hydroxide form. These resins require a strong acid and a strong alkali as regenerants and hence are not suitable for domestic use.
- The invention now provides a method for improving the dishwashing machine operation in that it enables the use of detergent products of lower alkaline content, comprising the removal of both the water-hardness cations as well as the bicarbonate anions from the intake water entering the machine during the washing programme by passing the intake water through a cation exchange resin and an anion exchange resin, characterised in that both ion exchange resins are regenerated with sodium chloride.
- According to the invention the dishwashing machine is operated with an additional ion-exchange device in the intake water line comprising a column containing an anion-exchange resin for removing said bicarbonate anions from the water in conjunction with a water-softening device.
- This device can be installed either as a separate device connected in series with the water-softening device either before or after it, or in parallel therewith, or it can form an integral part of a combined water-softening and decarbonating system. In the latter case the ion-exchange resin column contains a mixture of cation-exchange resin and anion-exchange resin.
- In this manner the water entering the dishwashing machine will be substantially free from Ca2+, Mg2+ and HC03- ions.
- It has been found that with such water washing can be accomplished with equally good results using a detergent product having a significantly lower alkaline content than the conventional products. Good washing results have been observed with a dishwashing machine modified according to the invention, using a product containing 30% sodium metasilicate, whereas in a conventional dishwashing machine the same results were only obtainable with products containing 49-50% sodium metasilicate.
- The anion-exchange resins which can be used in the present invention are known in the art and various types are commercially available, ranging from the very basic types to the slightly acid types. "Lewatit"@ anion-exchange resins, supplied by the Bayer Company, Leverkusen, Germany, are typical examples of readily available commercial products.
- Since the anion-exchange resins are those which can be regenerated with a solution of NaCI, such resins will be regeneratable with the same regeneration salt as that normally used for regenerating the water-softening resin. Regeneration may then take place simultaneously for both water-softening resin and the anion-exchange resin without any special measures. An example of such resin is the commercial product "Lewatit M 600", supplied by the Bayer Company.
- An example of a combined ion-exchange device according to the invention for installing in a dishwashing machine is shown schematically in the attached Figure 1. The figure shows a column (1) containing a mixture of anion- and cation-exchange resins and a container (2) for the regenerating salt. In operation water is taken in via line (3) and passes through the ion-exchange column, where it is softened and decarbonated at the same time before entering the machine at point (4). For regeneration, all or part of the water stream can be passed through the regenerating salt vessel (2) via line (5).
- In practice the whole water stream during the wash programme needs softening, but only the water stream for the main wash will need passing through the anion-exchanger for decarbonation. In the above embodiment, decarbonation of the water takes place during the whole wash programme, since the water stream cannot be by-passed from the anion-exchanger during pre-washing and rinsing. This by-passing is possible using an embodiment wherein the anion-exchange device is installed separately from the water-softening device, either in series or in parallel.
- A column containing the anion-exchange resin "Lewatit M 600" was installed in the water intake line of a Flandria dishwashing machine type R12 before the water-softening device.
- The tap water initially contained (64-78) 10-4 mole/I of HCO3-. After the water passed through the anion-exchange resin column, the concentration of bicarbonate ions was markedly reduced (max. 14. 10-4 mole/I). Fig. 2 is a graph showing the evolution of HC03- concentration in a dishwashing machine with and without an anion-exchanger column containing "Lewatit M 600", which was regenerated after each cycle with NaCI.
- The upper curve shows HC03- concentration in the machine without an anion exchange device.
- The lower curve shows HC03- concentration in the machine provided with an anion-exchange device.
- The regeneration efficiency of NaCI is clearly seen from the lower curve, since a low amount of HC03- was found after each cycle at point R.
- Washing experiments were made, using a Flandria type R 12 machine wherein a combined anion/cation-exchange device, as shown in Figure 1, is installed. The column had a capacity of 6 litres and contained 2 litres of cation-exchange resin "Lewatit S 100" ex Bayer Company and 4 litres of anion-exchange resin "Lewatit M 600" ex Bayer Company.
- The machine was operated according to a programme including the regeneration of the resins, using the following detergent products.
- (A) A standard machine dishwashing powder of the following nominal composition:
- 2% nonionic surface-active agent
- 37% sodium triphosphate
- 50% sodium metasilicate
- 5% sodium carbonate
- 1.5% K-dichloro cyanuric acid.
- (B) Experimental product similar to standard but containing 25% sodium metasilicate and 25% sodium sulphate.
- (C) Experimental product similar to standard but containing 30% sodium metasilicate and 20% sodium sulphate.
- The results were rated as follows:
- Coffee stains on cups and saucers A=C=B.
- The general conclusion can be made that using the device of the invention, the effectiveness of detergent products containing 30% sodium metasilicate is comparable with that of a product containing 50% sodium metasilicate.
Claims (1)
- A method for improving dishwashing machine operation comprising the removal of both water hardness cations and bicarbonate anions from the intake water entering the machine during the washing programme, by passing the intake water through a cation exchange resin and an anion exchange resin, characterised in that both ion-exchange resins are regenerated with sodium chloride.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7832016 | 1978-08-02 | ||
| GB3201678 | 1978-08-02 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0008819A1 EP0008819A1 (en) | 1980-03-19 |
| EP0008819B1 true EP0008819B1 (en) | 1983-05-11 |
Family
ID=10498818
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP19790200419 Expired EP0008819B1 (en) | 1978-08-02 | 1979-07-27 | Improvement to dishwashing machine operation |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0008819B1 (en) |
| DE (1) | DE2965369D1 (en) |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL207088A (en) * | 1955-05-12 | |||
| DE1628560A1 (en) * | 1967-01-18 | 1971-10-28 | Candy Spa | Device for descaling water in washing machines and dishwashers, in particular dishwashers |
| US3492159A (en) * | 1968-10-18 | 1970-01-27 | Economics Lab | Water conditioning |
| FR2026297A1 (en) * | 1968-12-16 | 1970-09-18 | Crane Co | Water demineralisation using an excharge - resins |
| DE2312126C2 (en) * | 1973-03-10 | 1983-02-24 | Bosch-Siemens Hausgeräte GmbH, 7000 Stuttgart | Dishwasher with a rinsing container and an ion exchanger for softening fresh water |
-
1979
- 1979-07-27 DE DE7979200419T patent/DE2965369D1/en not_active Expired
- 1979-07-27 EP EP19790200419 patent/EP0008819B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| EP0008819A1 (en) | 1980-03-19 |
| DE2965369D1 (en) | 1983-06-16 |
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