Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3677820 A
Publication typeGrant
Publication dateJul 18, 1972
Filing dateMay 28, 1970
Priority dateMay 28, 1970
Publication numberUS 3677820 A, US 3677820A, US-A-3677820, US3677820 A, US3677820A
InventorsRutkowski Beverly J
Original AssigneeWhirlpool Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method to prevent glassware etching in a dishwasher
US 3677820 A
Images(1)
Previous page
Next page
Description  (OCR text may contain errors)

July 18, 1972 u ws 3,677,820

METHOD TO PREVENT GLASSWARE E'ITCHING IN A DISHWASHER Filed Ma 28, 1970 INVENTOR BEVERLY J. RUTKOWSKI ATTORNEYS United States Patent 3,677,820 METHOD TO PREVENT GLASSWARE ETCHNG IN A DISHWASHER Beverly J. Rntkowski, Benton Harbor, Mich., assignor to Whirlpool Corporation Filed May 28, 1970, Ser. No. 41,186 Int. Cl. A471 /00; B08b 3/02 US. Cl. 134-25 A 8 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION In washing glassware particularly in mechanical dishwashers of the household type the detergent used to produce the washing solution is quite alkaline with the result that over a period of time the surfaces of the glassware are attacked by the washing solution to produce a permanent cloudy efiect due to the corrosion or etching of the glassware surface by the alkaline solution. This glassware etching or corrosion problem is particularly common in soft water areas, but the problem is not limited to such areas. There have been methods and apparatus proposed in the past for preventing such glassware etching or corrosion but these previously proposed methods and apparatus have depended on a galvanic action involving a sacrificial electrode or adding a corrosion inhibiting salt or oxide to the detergent solution.

SUMMARY OF THE INVENTION In the present invention the corroding or etching of the glassware in a mechanical dishwasher is substantially prevented by contacting the washing solution with a metal comprising either metallic zinc, metallic magnesium or a mixture thereof simultaneously with the applying of a detergent solution to the glassware in the washing portion of the cycle. Although this invention is not limited to any theory of operation it appears that the inhibiting effect of the metal is not the result of a galvanic action and the metallic zinc or magnesium or mixtures thereof does not function as a sacrificial electrode. What appears to be the case is that the washing solution slowly dissolves the metal and deposits it as a protective barrier layer on the glass surface. Because the metal is slowly dissolved it is of course necessary after a period of time to replace the used metal with a fresh metal structure.

One of the features of this invention therefore is to provide an improved method of substantially preventing corrosion of glassware during washing thereof by contacting the washing solution with metallic zinc, metallic magnesium or mixtures thereof.

Another feature of the invention is to provide a mechanical dishwasher for washing glassware which would ordinarily be subjected to corrosive conditions therein by including in the tub in which the glassware is retained during Washing a supply of metallic zinc, metallic magnesium or a mixture of these in position to be contacted by the washing liquid.

BRIEF DESCRIPTION OF THE DRAWINGS In the single figure of the drawing there is illustrated a mechanical dishwasher of the household type embodying Patented July 18, 1972 the apparatus of this invention with which the method of the invention is practiced.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the illustrated embodiment of the drawing the dishwasher disclosed is of the type described and claimed in the prior patent to J. B. Lyman No. 3,444,870 assigned to the same assignee as the present application. Thus, the dishwasher 10 is of the household type that comprises a cabinet 11 enclosing a tub 12 that contains a rack 13 for retaining glassware 14 as illustrated by the single glass held by the rack 13.

In order to circulate washing solution over the rack 13 and dishes including glassware 14 retained therein the bottom of the tub 12 is recessed to form a sump 15 in which is located a motor pump unit 16 that not only draws liquid from the sump 15 for circulation over the rack 13 but which also rotates the customary spray arm 17 through which the washing liquid is forced in sprays to contact articles held in the racks 13. As can be seen the arm 17 is positioned above the top 18 of the sump 15.

In order to prevent substantial corrosion of the glassware 14 by the washing liquid there is mounted on the side of the basket or rack 13 an elongated strip 20 comprising the metal of this invention. This metal may be either zinc, magnesium or a mixture of these and when mounted in this postiion is contacted by the circulating washing liquid substantially simultaneously with its contacting with the glassware 4. Preferably this mass or strip of metal has an exposed surface area of about sixty square inches with a thickness of at least inch.

In practicing the method of this invention it was noted that with the use of ordinary dishwasher detergent and particularly those containing sequestering materials such as polyphosphates the corroding of the glassware began almost immediately and after relatively few washings the cloudy effect produced on the glassware became quite noticeable. Because this is the result of etching the surface of the glassware and not due to a foreign deposit it was of course impossible as a practical matter to remove it.

In contrast, when metallic Zinc or magnesium was present such as by mounting the strip 20 in the tub 12 of the dishwasher and using the same detergent having a high polyphosphate content etching or corroding of the glassware could not be detected even after repeated washings of the glassware. Furthermore, the dissolution of the zinc or magnesium was so slow that it did not have to be replaced until after greatly extended periods of time.

The block of metal used in this invention may of course be any shape desired and is not limited to the illustrated elongated strip. Similarly, it may be mounted at any desired area in the liquid circuit where there is space available and where it will not materially interfere with the liquid flow.

Having described my invention as related to the embodiment shown in the accompanying drawing, it is my intention that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the appended claims.

The embodiment of the invention in which an exclusive property or privilege is claimed is defined as follows:

1. The method of substantially preventing corrosion of glassware during washing thereof with an alkaline detergent in a mechanical dishwasher comprising contacting an alkaline detergent solution With a solid piece of metal of the class consisting of zinc and magnesium and with said glassware for cleaning of said glassware.

2. The method of claim 1 wherein said metal comprises z1nc.

3. The method of claim 1 wherein said metal comprises magnesium.

4. The method of claim 1 wherein said contacting is accomplished by circulating said solution over both said glassware and said metal.

5. A mechanical dishwasher for washing glassware while substantially preventing corrosion thereof by a washing liquid, comprising: a tub in which said glassware is retained during said washing thereof; a solid piece of zinc in said tub, said metal having an exposed surface area of about sixty square inches with a thickness of at least A inch; and means for circulating said washing liquid in contact with said metal and with the glassware to prevent substantial corrosion of said glassware by said washing liquid.

6. The dishwasher of claim 5 wherein said metal comprises zinc.

7. The dishwasher of claim 5 wherein said means for contacting said liquid with said metal comprises means for mounting said metal in said tub and means for simultaneously circulating said liquid over said glassware and said metal in said tub.

8. A mechanical dishwasher for washing glass-ware while substantially preventing corrosion thereof by a washing liquid, comprising: a tub in which said glassware is retained during said washing thereof; a solid piece of zinc in said tub; and means for circulating said washing liquid in contact with said zinc and with the glassware to prevent substantial corrosion of said glassware by said Washing liquid.

References Cited UNITED STATES PATENTS 2,447,297 8/1948 Wegst et a1 252-156 X 3,278,446 10/1966 Irani 252156 X 2,957,813 10/ 1960 Reincrt l3429 X 3,444,870 5/1969 Lyman 134-179 MORRIS O. WOLK, Primary Examiner D. G. MILLMAN, Assistant Examiner US. Cl. X.R.

212; l3457 D, 58 D

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4443270 *Jul 12, 1982Apr 17, 1984The Procter & Gamble CompanyRinse aid composition
US4908148 *Feb 13, 1989Mar 13, 1990The Procter & Gamble CompanyLow foaming polyoxyalkylene nonionic surfactant, inorganic insoluble zinc compound, solvent
US4933101 *Feb 13, 1989Jun 12, 1990The Procter & Gamble CompanyImproved inhibition of glassware corrosion
US5624892 *May 19, 1995Apr 29, 1997Lever Brothers Company, Division Of Conopco, Inc.Process for incorporating aluminum salts into an automatic dishwashing composition
US6622736 *Dec 29, 1999Sep 23, 2003Reckitt Benckiser N.V.With P2O5
US6806245Sep 3, 2002Oct 19, 2004Reckitt Benckiser N.V.Ceramic compound releases an active agent (oxides of zinc, aluminum, tin, magnesium, calcium, strontium, silicon, titanium, zirconium, manganese, and lanthanum) to protect glassware from corrosion during washing and/or rinsing cycles
US6992052Dec 17, 2003Jan 31, 2006The Procter & Gamble Companyreacting zinc oxide with an organic or inorganic acid to form a zinc salt for use as a base or additive as a dishwashing rinse aid; cost effective, corrosion resistance
US7135448Jul 2, 2003Nov 14, 2006Ecolab Inc.Warewashing composition for use in automatic dishwashing machines, comprising a mixture of aluminum and zinc ions
US7153816Feb 17, 2004Dec 26, 2006Henkel Kommanditgesellschaft Auf Aktien (Henkel Kgaa)Dishwasher detergent with improved protection against glass corrosion
US7179776May 18, 2004Feb 20, 2007Reckitt Benckiser, N.V.Ceramic dishwashing composition for inhibiting corrosion of glassware
US7196044Jun 25, 2004Mar 27, 2007Ecolab, Inc.detergents including cleaning compounds, an alkaline source, and corrosion inhibitors, used for cleaning utensils and kitchenware in dishwahers
US7196045Feb 2, 2006Mar 27, 2007Ecolab Inc.Warewashing composition comprising a corrosion inhibitor with Al and Zn ions
US7276470Dec 19, 2002Oct 2, 2007Reckitt Benckiser N.V.Water soluble zinc-containing glass or ceramic and surfactant(s)
US7361632 *Jul 25, 2005Apr 22, 2008Reckitt Benckiser N.V.Contacting glassware with water soluble glass comprising zinc oxide, phosphoric anhydride, sulfur trioxide, and alkali and/or alkaline earth metal oxides; transparency
US7452853Aug 7, 2006Nov 18, 2008Ecolab Inc.detergents including cleaning compounds, an alkaline source, and corrosion inhibitors, used for cleaning utensils and kitchenware in dishwahers
US7456142 *Jul 11, 2007Nov 25, 2008Reckitt Benckiser N.V.washing the glassware with a composition comprising P2O5, Li2O or Na2O, SO3 and ZnO; keeping transparency
US7524803Jan 30, 2007Apr 28, 2009Ecolab Inc.Warewashing composition for use in automatic dishwashing machines comprising an aluminum/zinc ion mixture
US7638473Oct 13, 2008Dec 29, 2009Ecolab Inc.Warewashing composition for use in automatic dishwashing machines, and methods for manufacturing and using
US7741236 *May 29, 2009Jun 22, 2010Reckitt Benckiser N.V.Water-soluble glass composition
US7759299Jul 24, 2006Jul 20, 2010Ecolab Inc.Warewashing composition for use in automatic dishwashing machines
US7829516Nov 12, 2009Nov 9, 2010Ecolab Usa Inc.Warewashing composition comprising a Zn/Al corrosion inhibitor for use in automatic dishwashing machines
US7858574Jun 8, 2010Dec 28, 2010Ecolab Usa Inc.Diluting a corrosion resistant washing detergent with water containing a cleaning agent containing a surfactant, alkaline source, a corrosion inhibitor for reducing corrosion of a glass, sorce of water soluble aluminum ions, source of water soluble calcium or magnesium ions; zinc-free; washing glass
US7939483 *Mar 31, 2010May 10, 2011Reckitt Benckiser N.V.Water-soluble glass as corrosion protector in dishwashing machines
US8097576 *Jan 24, 2011Jan 17, 2012Reckitt Benckiser N.V.Composition for the protection of glassware in a dishwashing process
US8216990 *Jan 24, 2011Jul 10, 2012Reckitt Benckiser N.V.Composition for protection of glassware in dishwasher
DE10010209A1 *Mar 2, 2000Sep 13, 2001Reckitt Benckiser NvUse of ceramic dishwashing composition for protection of glassware from corrosion, involves using ceramic composition comprising at least one compound which releases active agent to protect glassware
EP0070587A1 *Jul 1, 1982Jan 26, 1983THE PROCTER & GAMBLE COMPANYRinse aid composition
EP0383480A1 *Feb 7, 1990Aug 22, 1990THE PROCTER & GAMBLE COMPANYRinse additive compositions providing glassware protection
EP0383482A2 *Feb 7, 1990Aug 22, 1990THE PROCTER & GAMBLE COMPANYGranular automatic dishwasher detergent composition providing glassware protection
EP0387997A2 *Feb 7, 1990Sep 19, 1990THE PROCTER & GAMBLE COMPANYLiquid automatic dishwashing compositons providing glassware protection
EP1961803A1May 19, 2004Aug 27, 2008Reckitt Benckiser N.V.Composition for the protection of glassware in a dishwashing process
EP2194115A2May 19, 2004Jun 9, 2010Reckitt Benckiser N.V.Composition for the protection of glassware in a dishwashing process
EP2263980A1 *Jun 16, 2010Dec 22, 2010Innovent e.V. TechnologieentwicklungCorrosion protection agent for glass
EP2767580A2May 19, 2004Aug 20, 2014Reckitt Benckiser N.V.Composition for the protection of glassware in a dishwashing process
WO2001064823A1 *Mar 2, 2001Sep 7, 2001Karlheinz Ulrich Gerhard HahnCeramic dishwashing composition
WO2012140438A1Apr 13, 2012Oct 18, 2012Revolymer LimitedNovel composite
WO2012140442A1Apr 13, 2012Oct 18, 2012Revolymer LimitedParticles with hydroxyl vinylic copolymer coating sensitive to ionic strength
WO2012153143A2May 11, 2012Nov 15, 2012Reckitt & Colman (Overseas) LimitedImproved composition
Classifications
U.S. Classification134/25.2, 134/58.00D, 134/57.00D, 422/40
International ClassificationA47L15/00
Cooperative ClassificationA47L15/0049, A47L15/0002, A47L2601/02
European ClassificationA47L15/00A