US3403884A - Pilot-operated valve - Google Patents

Description

Oct. 1, 1968 T, E NOAKES ET AL 3,403,884

P ILOT -OPERATED VALVE Filed July 26, 1965 fa. J

I NVENTORS 77-/onAs E. NoAKs BY Onew/N A? GRA/VL Arroz/vins United States Patent O 3,403,884 PILOT-OPERATED VALVE Thomas E. Noakes, Detroit, and Darwin R. Grahl, Lincoln Park, Mich., assignors to American Radiator & Standard Sanitary Corporation, New York, N.Y., a corporation of Delaware Filed July 26, 1965, Ser. No. 474,700 8 Claims. (Cl. 251-30) ABSTRACT OF THE DISCLOSURE The invention described herein involves an electromagnetic pilot-operated valve with the coil or coils of the pilot mounted on the body of the main valve rather than on the valve body cover. The coil is either encapsulated in the plastic valve body or mounted on an exterior surface of the valve body.

This invention relates to pilot-operated valves such as are used for example to control liquid flow in clothes washing machines, dishwashers, and machines for dispensing coffee, soft drinks and other similar liquids.

One conventional pilot-operated valve comprises a plastic valve body having an overlying main diaphragm valve element equipped with a central pilot opening therein. A cup-shaped cover overlies the diaphragm and is pro-vided with a tubular extension which houses a plunger armature. A solenoid coil surrounds the tubular extension for moving the armature toward or away from the pilot opening in the main diaphragm.

One disadvantage of the conventional arrangement resides from the fact that the armature must have a relatively long stroke to accommodate movement of the diaphragm; this entails a relative large and expensive solenoid. To overcome the disadvantages of the conventional arrangement a valve has been proposed wherein the pilot armature operates against a xed pilot opening; with such an arrangement the armature need only have a relatively short movement which can be produced by a small low cost solenoid.

To further reduce the valve cost a valve has ibeen proposed wherein the solenoid coil is encapsulated within a cover which is formed as a plastic molding. Such an arrangement eliminates certain parts which were heretofore formed separately, including separate metal mounting brackets, metal cover elements, magnetic frames, and screws for clamping the frames onto the cover elements. In the case of mixing valves for clothes washing machines both solenoid coils can be encapsulated within a single plastic cover, thus eliminating duplicate brackets, cover elements, and magnetic frames.

The present invention is directed to an arrangement which is in some respects similar to the above-described cover-encapsulated coil arrangement. However, in an effort to further reduce the cost we mount the coil or coils on the valve body rather than on the cover. In one form of the invention We encapsulate the coil or coils directly in the valve body, thereby eliminating one of the moulding operations necessary in the cover-encapsulated coil arrangement. In another form of the invention we mount the coil on an exterior surface of the valve body; such an arrangement permits us to use a relatively low cost stamping for the cover element in place of the plastic molding.

An object of the present invention is to provide an improved low cost pilot-operated valve wherein a solenoid operator for the pilot valve element is carried by the valve body remote from the main valve element, thereby permitting the pilot element to have a short stroke without interfering with movement of the main valve element.

A further object is to provide a pilot-operated valve wherein the solenoid operator is mounted on the valve ICC body rather than on the valve body cover as under previous practice. This feature enables the cover to be formed as a cheap metal stamping, and reduces the number of plastic molding operations involved in forming and mounting the coil or coils.

A general object is to provide a pilot-operated valve wherein the components can be assembled from one side only of the valve body, thereby simplifying the assembly process.

Other objects of this invention will appear from the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

In the drawings:

FIGURE l ls a sectional view taken on line 1-1 of FIG. 3;

FIG. 2 is a sectional view taken on line 2-2 in FIG. 3;

FIG. 3 is a top plan view of the valve shown in FIGS. 1 and 2;

FIG. 4 is la fragmentary view of a valve constituting another embodiment ofthe invention;

FIG. 5 is a fragmentary view of a valve constituting a further embodiment of the invention; and

FIG. 6 is an enlarged view taken in the same plane as FIG. 2.

Before explainnig the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

As shown in FIG. l the invention comprises a molded plastic valve body 10, preferably formed of nylon or polyphenylene-oxide, said body dening an inlet 12 for water of one temperature, an inlet 13 for water of another temperature, and an outlet 16 for mixed temperature water or water of either temperature, depending on which of the diaphragm valve elements 18 and 20 are opened to liquid flow.

Inlet 12 includes an annular inlet chamber 22, a concentrically disposed outlet chamber 23 and an intervening annular valve seat 25 which underlies the central portion of diaphragm 18. As shown in FIG. 6-, wall portion 26 of the valve body is cut away to form a passage 27 for admitting liquid to a porous rod-like strainer 28, formed for example of bonded wool or bonded cellulose acetate. The iilter is arranged within a chamber 29 in the general manner shown in co-pending application, Ser. No. 450,- 086, tiled Apr. 22, 1965.

Overlying chamber 29 and valve seat 25 is an elastomeric element 30 which defines the aforementioned diaphragm 18 and a flat sealing portion 32, said portion having a flow aperture 33 therethrough for conducting pilot liquid from strainer 28 into a. groove-like recess 35 formed in the underside of a metal cover 36. Cover 36 has a central portion thereof spaced from diaphragm 18 to dene a control chamber 38. When liquid is trapped in control chamber 38, as by the pilot-valve means to be described hereinafter, the liquid pressure therein is sufficient to depress diaphragm 18 to its illustrated position closed against main valve seat 25. When the pilot valve means is operated to open chamber 38 the pressure in inlet chamber 22 is suiiicient to raise diaphragm 18 away from seat 25.

Aforemeutioned elastomeric element 30 includes a ii-at extension 50 which overlies an extension 52 formed integrally with the valve body 10, said extension having a cavity therein defining an exhaust chamber 53 for the pilot liquid previously trapped in control chamber 3S. Elastomeric portion 50 defines an inlet port 55 for charnber 53, said inlet port receiving its supply of liquid from a groove-like recess 56 formed in the underside of cover element 36. To reinforce the elastomeric element there may be provided an annular metal disc 57. Liquid flowing into chamber 53 can flow freely into a groove 58 which communicates with a vertical duct 71 (FIG. 1).

The previously referred-to pilot valve means comprises a solenoid-armature means wherein the solenoid portion thereof includes a di-electric spool 59 having a tubular portion 60 and radiating end walls 61 and 63. Trained about spool 59 is an electrical winding 65, the ends thereof being suitably connected to spade-type terminals 66 which have their ends inserted into slots in the spool end wall 61 in a conventional manner. The armature portion of the solenoid-armature means comprises a `cylindrical armature plunger 68 fioatably slidably positioned within spool 59 and urged upwardly by a compression spring 70, said spring having its lower end positioned against a shoulder formed on the rod portion of a rivet-like pole piece 72.

The solenoid (comprising spool 59, windings 65 and terminals 66) is formed Ias a sub-assembly separate from valve body 10. Preparatory to the process of molding valve body 10, pole piece 72 and the solenoid sub-assembly are positioned as an insert in the mold cavity, after which the valve body is molded to its illustrated configuration, with the solenoid coil being automatically encapsulated into the valve body as part of the valve body molding operation. The mold preferably includes 21 hexagonal pin element which fits within a hexagonal bore in spool 59 to maintain a hexagonal guide surface for the plunger 68. After the solenoid and valve body have been molded together, filter 28, spring 70, plunger 68 and plate 57 are inserted into their cooperating chambers, and elastomeric element 30 is installed thereabove, after which cover element 36 is clamped onto the valve body by screws 75.

FIG. 2 is a sectional view taken through the passage structure which handles the liquid admitted to inlet 12. It will be understood that a similar passage structure is provided to handle the liquid admitted to inlet 13, both liquids being discharged into the common outlet 16.

In some instances it is desirable to equip the valve with mechanism for providing a substantially const-ant volumetric fiow through the valve in spite of substantial variations in inlet supply pressures. In the illustrated valve this flow control means takes the form of a resilient fiow control annulus 79 formed for example `as shown in U.S. Patent i 2,775,984, and disposed within a pocket 88 which is closed by a portion 82 of the aforementioned elastomeric element 30.

During service a small portion of the liquid admitted to inlet 12 is directed through passage 27 to filter element 28, the filtered liquid then passing through port 33 and passage 35 to the control chamber 38. In the event that solenoid winding 65 is de-energized, spring 70 will urge the pilot valve element 68 to its illustrated closed position, whereupon the liquid pressure in chamber 38 will close the diaphragm 18 against seat 25. Energization of winding 65 causes element 68 to move downwardly toward pole piece 72, whereupon liquid in chamber 38 is exhausted therefrom through a passage system comprising passage 56, port 55, chamber 53, groove 58 and duct 71. The valve can of course be used in an inverted position if desired.

It will be noted that plunger 68 has a very limited travel which can be produced lby a coil having a relatively small number of electrical turns. The plunger is remote from the diaphragm 18 such that the diaphragm can enjoy a relatively long stroke without interference from the plunger. The coil is encapsulated and mounted by the act of form'- ing the valve body, which reduces the number of parts and number of assembly operations. Cover 36 can be a relatively low cost stamping.

The `arrangement fragmentarily shown in FIG. 4 is similar to the FIG. 2 arrangement, except for the way in which the solenoid means is constructed and mounted. In the FIG. 4 arrangement the slab-like valve body extension 52a is provided with a hollow tubular portion 83 which flotatably guides the hexagonally cross sectioned plunger 85. Surrounding tubular portions 83 is a solenoid means comprising a di-electric spool 59 having radial end anges 61 and 63, said spool having an electrical winding trained therearound, the ends thereof being secured to spade-type terminals 66. The solenoid is encapsulated within a plastic encapsulation 87, after which the tubular pole pieces 88 and 89 are inserted therein preparatory to assembly of the solenoid onto tubular portion 83. Preferably each pole piece is formed as an extrusion from a horizontal leg of an L-shaped magnetic frame, the vertical legs thereof not being visible in FIG. 4. The two L- shaped frames are assembled onto the encapsulated coil with the vertical leg of each L-shaped member engaging or interlocking with an end area of the horizontal leg of the other frame member, thus completing the magnetic circuit. After assembly of the coil and magnetic frames onto the valve body the entire assembly is secured in place with a spring retainer or the like 92..

The invention as shown in FIG. 2 includes a filter 28 operatively located between linlet chamber 22 and control chamber 38. However, in the event it was decided to do without the filter, the liquid could be conducted directly from chamber 22 to chamber 38, as by means of a small opening in diaphragm portion 39. The small opening is of course not used in the FIG. 2 diaphragm because a pilot fiow path is afforded through filter 28.

FIG. 5 illustrates van arrangement in which the heavy stamping 36 of FIGS. 1 and 2 is replaced by a thinner 0r lighter stamping 36a. Retention of the lighter stamping may be accomplished by means of an annular clamping plate 36h of heavier gage material. This `arrangement would of course save somewhat on material cost, but would necessitate the use of an additional component part with associated assembly cost.

The invention has been described and illustrated by means of specific concrete embodiments, but it will of course be understood that variations and modifications thereof may be utilized as come within the spirit of the invention as encompassed by the appended claims.

What is claimed is:

1. A pilotoperated valve comprising a molded plastic valve body having a face thereof configured to define an annular inlet chamber, an outlet chamber within the inlet chamber and an intervening annular valve seat; an elastomeric diaphragm disposed on said valve body face and overlying the chambers and valve seat; a cover clampingly engaging the diaphragm periphery but spaced from the central portion thereof to permit said central portion to flex toward and away from the valve seat for controlling fluid flow therepast; the space between the cover and diaphragm central portion constituting a control chamber; a valve body extension formed integrally with the plastic valve body and defining a pilot uid exhaust chamber communicating with the aforementioned outlet chamber; said cover having an extension overlying the valve body extension; resilient pilot seat means clamped between the valve Ibody extension and cover extension and defining an inlet port for the exhaust charnber; first pilot fiuid passage means operatively located to conduct iiuid lfrom the aforementioned inlet chamber to the control chamber; second pilot fluid passage means formed by the cover extension and located to conduct fluid from the control chamber to the exhaust chamber inlet port; an armature disposed in the aforementioned exhaust chamber for movement toward and away from the exhaust chamber inlet port to control fiuid fiow therethrough; and a solenoid located on the valve body extension in operative association with the armature to move same -away from the port; said resilient seat means having its armature-engaging surface presented to the exhaust chamber, and said armature comprising van element movable toward said surface to close the exhaust chamber inlet port; the aforementioned solenoid comprising a dielectric spool coaxial with the armature element, the axis of said spool and armature element being parallel to the axis of the aforementioned inlet and outlet chambers.

2. The valve of claim 1 wherein the solenoid spool is encapsulated within the valve body extension.

3. The valve of claim 2 wherein the solenoid cornprises a pole piece having a rod-like portion thereof disposed within an end portion of the spool in registry with the armature; said armature comprising a plunger slidably engaging an inner surface of the spool for reciprocable movement between the aforementioned port and pole piece.

4. The valve of claim 1 wherein the valve body extension comprises a slab-like portion paralleling the aforementioned valve body face and a tubular portion extending right angularly from the slab-like portion, said armature element being floatably positioned within the tubular portion.

5. The valve of claim 4 wherein the solenoid spool surrounds the tubular portion of the valve body extension.

6. The valve of claim 1 wherein the pilot seat means comprises an integral extension of the diaphragm; said diaphragm and its extension being formed as a single elastomeric element.

7. The valve of claim 1 wherein the cover and its extension are formed of a single metal plate of substantially uniform thickness throughout its area, said plate being deformed away from the valve body to provide the aforementioned control chamber and second passage means.

8. The valve of claim 1 wherein the exhaust chamber communicates with the outlet chamber via a passage system which includes a groove in the aforementioned valve body face.

References Cited UNITED STATES PATENTS 926,389 6/ 1909 Collin 251-30 X 1,901,119 3/1933ly Putnam 251-45 X 2,712,324 7/1955 Lund 137-606 2,788,789 4/ 1957 Asplund 251-45 3,022,039 2/1962 Cone et al. 251--46 3,112,094 11/1963 Nees et al 251-30 3,143,131 8/1964 Spencer 251-138 X 3,245,650 4/ 1966 Brennan 251-45 3,249,120 5/ 1966 Kozel 137-606 3,289,697 12/ 1966 Kozel et al 137-606 3,300,175 1/1967 Kozel 251-30 FOREIGN PATENTS 477,129 12/ 1937 Great Britain.

87,392 9/ 1936 Sweden.

M. CARY NELSON, Primary Examiner.

R. C. MILLER, Assistant Examiner.

Images