Acetal (POM) Water Valve

Abstract

An acetal co-polymer valve body and/or spin ring in a solenoid operated dishwasher or washing machine valve has been found to reduce a likelihood of breaking when subjected to freezing and thawing conditions over the polypropylene and glass filled nylon components normally employed in the marketplace.

Claims

1. A residential appliance valve comprising: a valve body having an inlet and an outlet; an armature moving relative to a guide tube, said armature having an armature tip connected to a diaphragm insert which selectively seals against a diaphragm on the valve body to thereby provided a closed configuration preventing flow from the inlet to the outlet; said armature movable to unseat the diaphragm insert from the diaphragm to permit flow through the diaphragm in an open configuration; wherein the valve body is formed of acetal co-polymer.

2. The residential appliance valve of claim 1 wherein the valve is located within one of a dishwasher and a washing machine.

3. The residential appliance valve of claim 2 further comprising a spin ring connecting the guide tube to the valve body.

4. The residential appliance valve of claim 3 wherein the spin ring is formed of acetal co-polymer.

5. The residential appliance valve of claim 1 wherein the armature is spring biased with a spring.

6. The residential appliance valve of claim 5 wherein the valve fails shut upon failure to receive sufficient voltage to maintain the armature and valve in an open configuration.

7. A residential appliance valve comprising: a valve body having an inlet and an outlet; an armature moving relative to a guide tube, said armature having an armature tip connected to a diaphragm insert which selectively seals against a diaphragm on the valve body to thereby provided a closed configuration preventing flow from the inlet to the outlet; said armature movable to unseat the diaphragm insert from the diaphragm to permit flow through the diaphragm in an open configuration; and a spin ring retaining the guide tube to the valve body; wherein the spin ring is formed of acetal co-polymer.

8. The residential appliance valve of claim 7 wherein the valve is located within one of a dishwasher and a washing machine.

9. The residential appliance valve of claim 8 wherein the armature is spring biased with a spring.

10. The residential appliance valve of claim 9 wherein the valve fails shut upon failure to receive sufficient voltage to maintain the armature and valve in an open configuration.

11. The residential appliance valve of claim 10 wherein the spin ring is formed of acetal co-polymer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The FIGURE is an exploded view of a water valve such as commonly utilized in a dishwasher or washing machine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0016] The FIGURE shows an exploded view of a water valve 20 which can be a dishwasher valve or a washing machine valve. Often washing machine valves have pairs of valves connected together to receive hot and cold water inlets. Dishwashers typically have a single water inlet. While there are many parts in a valve 20 normally there is a coil assembly 12 housing a solenoid configured to operate on an armature 8 which moves relative to a guide tube 10 to move an armature tip 7 and diaphragm insert 6 up and down so as to selectively seal against diaphragm 5. The armature 8 may be spring biased such as with spring 9 so that the valve 20 fails in a shut or off configuration and/or shuts when the voltage is not high enough to hold the armature 8 (and through the valve 20) in the open position. The diaphragm 5 may be set within a valve body 1 having an inlet 22 and an outlet 24. The inlet 22 may be equipped with a screen 4, a flow washer 3, a flow regulator 2 and/or other components.

[0017] While prior art designs have manufactured the water housing, or valve body 1, the solenoid housing, the spin ring 11, and possibly other components out of polypropylene or glass filled nylon, such components have a tendency to become brittle after repeated flexing when subjected to freezing temperatures and after thawing out either during the freezing step or when thawing. Accordingly, the applicant is providing the valve body 1 and spin ring 11 as acetal co-polymer components which is not believed to have ever been done before with residential appliances, particularly for dishwashers and washing machines. Other embodiments of valves 20 may have different constructions but those components containing water (which may freeze or have increased pressure due to freezing) may be acetal copolymer.

[0018] Acetal co-polymer would not normally be the first material which comes to mind to replace polypropylene or glass filled nylon. Acetal is subject to UV degradation and can be sensitive to non-uniform part geometry as it may have excess of shrink, warp and voids. Acetal can also be flammable at a high temperature and be difficult to bond. Normal moldings can endure hot temperatures but defective ones can crack. These disadvantages have apparently led manufacturers to rely on the polypropylene and glass-filled nylon construction for valve bodies and spin rings.

[0019] While most dishwashers and washing machines have hot water therein, normally not over 110° F. in washing machines but potentially higher in dishwashers, the water valves providing input water do not normally provide water at temperatures above 120° Fahrenheit. They are also somewhat spaced apart from any higher temperatures that may be experienced other than the normal temperature of hot water which does not normally exceed 120° Fahrenheit in residential applications. For laundry valves the cold water in washing machines would normally be less than 80° Fahrenheit.

[0020] Accordingly, one of ordinary skill in the art would not be motivated to use acetal co-polymers as pressured components of the valve because most dishwashers and washing machines are not normally subjected to temperatures below −30° Fahrenheit. Polypropylene and glass-filled nylon components such as for the valve bodies 1 and spin ring 11 or other components subjected to pressure function more than satisfactory at those temperatures.

[0021] A problem arises in the cycling between freezing and thawing, for which at least one manufacturer has a rather stringent new test which consistently fails the applicant's polypropylene and glass-filled nylon options currently provided in the market. The acetal co-polymer based water valve body 1 and spin ring 11 have found to operate more than satisfactory when made of acetal co-polymers. In fact, these components, and the valve 20, survived two times the testing requirement cycle number of the applicant's customer's test while none of the applicant's glass-filled nylon or polypropylene components manufactured out of the exact same molds have been able to survive the tests.

[0022] Numerous alterations of the structure herein disclosed will present themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to the preferred embodiment of the invention which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.