US3625245A

US3625245A - Tip for valve member and method of assembling same

Info

Publication number: US3625245A
Authority: US
Inventors: William A Biermann
Original assignee: Controls Company of America
Current assignee: Eaton Corp
Priority date: 1969-11-13
Filing date: 1969-11-13
Publication date: 1971-12-07
Anticipated expiration: 1988-12-07
Also published as: NL7015189A; FR2069207A5

Abstract

The needle valve stem of a float-controlled valve is provided with a tip made of resilient material such as a fluoroelastomer. The end of the valve stem includes a cylindrical bore and the resilient tip has a cylindrical portion disposed in that bore which has a relaxed diameter greater than the diameter of the bore. The tip is inserted in the bore by stretching its cylindrical portion axially to reduce the diameter of the cylindrical portion. Once in the bore, the stretching force is released whereupon the tip tends to return to its relaxed state and in doing so creates an inherent bias which acts against the bore walls to hold the tip on the valve stem. The tip includes an annular, convex in transverse cross section projection which engages an unobstructed surface surrounding the valve orifice through which flow occurs. The tip closes the orifice to flow and does so without protruding into the orifice.

Description

United States Patent [72] Inventor William A. Biermann Brooktield, Wis. [21] Appl. No. 876,532 [22] Filed Nov. 13, 1969 [45] Patented Dec. 7, 1971 [73] Assignee Controls Company of America Melrose Park, Ill.

[54] TIP FOR VALVE MEMBER AND METHOD OF ASSEMBLING SAME 6 Claims, 4 Drawing Figs.

[52] U.S. Cl 137/434, 251/357 [5]] 1nt.C1 Fl6k 31/26 [50] Field ol Search 137/409, 410, 315, 434; 25 1/333, 334, 356, 357, 358; 29/157.1, 156.7 A, 450

[56] References Cited UNITED STATES PATENTS 2,558,589 6/1951 Skolfield 29/450 X 2,654,560 10/1953 251/357 X 2,687,277 8/1954 251/357 X 2,693,929 11/1954 251/357X 3,213,524 10/1965 Pratheretal. 3,381,351 5/1968 Szwargulski ABSTRACT: The needle valve stem of a float-controlled valve is provided with a tip made of resilient material such as a fluoroelastomer. The end of the valve stem includes a cylindrical bore and the resilient tip has a cylindrical portion disposed in that bore which has a relaxed diameter greater than the diameter of the bore. The tip is inserted in the bore by stretching its cylindrical portion axially to reduce the diameter of the cylindrical portion. Once in the bore, the stretching force is released whereupon the tip tends to return it its relaxed state and in doing so creates an inherent bias which acts against the bore walls to hold the tip on the valve stem. The tip includes an annular, convex in transverse cross section projection which engages an unobstructed surface surrounding the valve orifice through which flow occurs. The tip closes the orifice to flow and does so without protruding into the ori- ,PATENIEMEB 71971 3625245 Jm errtor BACKGROUND OF INVENTION This invention relates to valves and to resilient tips for movable valve members and, more particularly, to the connection of the tip to the valve stem, the manner of making that connection, and the closure of the. fixed orifice to flow by the resilient tip.

Resilient tips have been used in valves to achieve valve closure. Various types of connections have been proposed for mounting the tips on the valve stem, these have generally taken the form of bonding, mechanical fasteners, mechanical interlocks, etc. For the most part these methods of attachment have not been entirely satisfactory for a number of reasons among which are that they have been relatively difficult to assemble, complex in construction, and not completely reliable.

This invention is concerned with providing a resilient tip on a movable valve member and connecting that tip to the valve member.

SUMMARY OF INVENTION Among the general objects of this invention are to provide an improved and simplified connection of a resilient tip on a movable valve member and one which facilitates the assembly of the tip to the valve member; and, furthermore, to achieve an improved closure of a valve orifice with the resilient tip.

For the achievement of these and other objects, this invention proposes an arrangement wherein a movable valve member is provided with a bore in the end thereof. A resilient tip is supported in the bore. To connect the tip to the movable valve member the bore is provided with opposed wall portions which are spaced a preselected distance apart. The resilient tip includes a portion which projects outwardly from the movable valve member and a second portion adapted to extend into the bore of the movable valve member. When the resilient tip is relaxed, the second portion has a transverse dimension which is greater than the preselected distance between the opposed bore wall portions. To assemble the tip onto the movable valve member, the second portion of the tip is stretched so that it becomes elongated and its transverse dimension is reduced sufficiently for insertion into the bore. Once in the bore, the stretching force on the second portion of the tip is released and, due to its resiliency, that portion tends to return to its relaxed position. This provides an inherent bias which maintains engagement between the tip and the opposed walls of the bore thereby securely holding the tip assembled on the movable valve member.

Preferably, the resilient tip also includes a bore extending into the second portion thereof. This bore facilitates stretching the second portion of the tip and moreover, permits a suitable elongated tool to be inserted into the tip. The tip can be stretched on the tool and the tool provides the instrument by which the tip is inserted in the valve member bore.

Also it is preferred that the projecting portion of the tip is annular and also is convex in transverse cross section. The resilient tip is movable to close a fixed orifice of the valve to flow through the valve. The fixed orifice is surrounded by an unobstructed surface and the annular portion of the tip engages the unobstructed surface. The movable valve member has generally unobstructed movement toward the unobstructed surface generally throughout the extent of the projecting portion of the tip. Throughout this movement of the movable valve member is a valve closing or sealing direction, the annular projection does not protrude into the fixed orifice.

DESCRIPTION OF DRAWINGS FIG. 1 is a view of a float-controlled oil valve in which this invention is embodied;

FIG. 2 is an enlarged section view of a portion of an assembled valve stem and resilient tip together with the fixed orifice illustrating the cooperation between the tip and orifice to close the valve to flow;

FIG. 3 is an exploded view of the tip and a portion of the valve stem illustrating the relationship between the relaxed resilient tip and the bore of the valve stem; and

FIG. 4 illustrates a step in assembling the tip.

DESCRIPTION OF PREFERRED EMBODIMENT The invention is illustrated as embodied in a float-actuated oil flow control valve 10. However, the invention is specifically concerned with the resilient tip used on the valve stem and the manner of connecting that tip to the valve stem and, in its more specific aspects, to the manner in which closure of the valve to flow is achieved. Accordingly, the invention has application broadly to valves and is not necessarily limited to any particular type of valve or valve usage.

In valve 10 flow occurs from inlet 14 through passage 12 into float reservoir 16. The construction and arrangement of needle valve stem 18, float 20, and the connection between float 20 and the needle valve stem can take any generally accepted form. The valve can also be provided with a safety cutotf float 21 and a cutoff actuator 24. The construction and arrangement illustrated is generally that disclosed and claimed in US. Pat. No. 2,547,995 of William A. Biermann et al., entitled Fluid Flow Control Mechanism" and assigned to the assignee of this application. Reliance is placed on this patent for a more complete description of the valve structure should such a description become necessary. As alluded to briefly above, the amount of flow through valve I0 is controlled by the valve element which control flow spicifically through passage I2 from inlet 14 to valve chamber 16. Needle valve stem 18 opens and closes passage 12 by moving axially with respect to passage l2 to close fixed orifice 26 provided in that passage.

Particular reference will now be made to FIG. 2-4 for a description of resilient tip 28 and its connection to valve stem 18. End 30 of the valve stem is provided with a cylindrical bore 32. Tip 28 is engaged in the bore and is held on the valve stem solely by the frictional engagement between the tip and the bore walls.

More specifically, tip 28 includes a portion 34 which, when the tip is assembled on the valve stem, projects axially from the end of the valve stem and is the part of the tip which cooperates in closing orifice 26 to flow. The tip also includes a cylindrical portion 36 which fits into bore 32. Tip 28 is made of a suitable resilient material, such as a fluoroelastomer, so that the tip is deformable but will tend to return to a normal relaxed state when the deforming force is released. The relaxed state of the tip is illustrated in FIG. 3 and in this state portion 36 has a diameter which is greater than the diameter of bore 32. The tip being resilient can be deformed, specifically it can be stretched along the axial extension of portion 36 to reduce the diameter of that extension for insertion into the valve stem bore. In the stretched condition the tip is inserted into the bore and released. Upon release the tip tends to return to its normal state. However, since the bore diameter is less than the relaxed diameter of portion 36, that tip portion cannot return fully to its relaxed state. Consequently, an inherent biasing force is provided urging the tip into engagement with the bore walls to hold the tip on the valve stem.

With this arrangement it will be noted that opposed portions of the walls of bore 32 define a transverse dimension (e.g., a diameter) and this transverse dimension is less than a corresponding transverse dimension (e.g., a diameter) of tip portion 36 in its relaxed state. Friction engagement is then provided between the tip and the bore walls to securely hold the tip on the valve stem.

Preferably, tip 28 is provided with an interior bore 38. This bore will accommodate a suitable tool such as rod 40 upon which the tip can be stretched in an axial direction to reduce the diameter of the cylindrical portion, this is illustrated by the full line of FIG. 4. Rod 40 also facilitates insertion of the tip into bore 32 while the tip is in a stretched condition. That is, rod 40 is inserted into bore 38 and the tip is stretched over the rod to reduce the diameter of tip portion 36 to less than that of bore 32 whereupon the tip is inserted in bore 32. Rod 40 is then removed releasing tip portion 36 and allowing it to expand into engagement with the walls of bore 32 as described above.

This arrangement provides a simplified and effective manner of mounting a resilient tip onto a valve stem.

A further problem encountered in the use of resilient valve tips to close an orifice is the problem of the tip protruding into the orifice, in this instance orifice 26. When such protrusion occurs, the sealing surface of the tip is indented and after continued use the tip indentation may take a relatively permanent set. Any such set can eventually interfere with proper seal off at the orifice since there is no assurance that the tip will engage in the orifice in the same manner upon each operation. To achieve effective seal off at orifice 26, portion 34 of tip 28 is generally annular and is provided with a convex outer surface, i.e., the annular tip portion has a convex configuration in transverse cross section as seen in FIGS. 2 and 3. Surface 42 immediately surrounding orifice 26 is planar and unobstructed and it is on this surface thattip 28 makes sealing engagement. The valve stem is positioned so that the annular projection 34 engages surface 42 but at areas spaced laterally from the walls of orifice 26. It will be noted that the valve stem is capable of unobstructed movement toward orifice 46 in pressing tip 28 into sealing engagement with surface 42. The valve stem and portion 34 of the valve tip are so constructed and arranged that through out this unobstructed sealing movement of the valve stem toward surface 42, the valve tip remains laterally spaced from the orifice and does not protrude into the orifice. This arrangement provides an effective seal at the orifice even through extended usage and does not require close tolerance to be held either in manufacturing or assembly of the valve elements.

I claim:

1. A flow control valve comprising, in combination,

a valve member including a fixed orifice through which flow occurs,

a movable valve member having an end,

a generally resilient tip carried on said end and movable with said valve member,

means for moving said valve member relative to said orifice to move said tip selectively into and out of closing engagement with said orifice,

means defining a bore in said end of said movable valve member with said bore having generally opposed wall portions defining a transverse dimension,

said tip including a first portion projecting from said end and a second portion having a transverse dimension and an extension generally normal to said transverse dimension thereof, said tip characterized by having a normal relaxed state wherein said transverse dimension thereof is greater than said transverse dimension of said bore and said tip being stretchable along its extension to reduce the tip transverse dimension and tending to return to its normal relaxed state from said stretched state when released whereby stretching of said tip extension reduces said transverse tip dimension for insertion in said bore and release of said tip causes said tip to expand in the direction of its transverse dimension to engage said wall portions,

means defining an interior bore in said resilient tip extending through said first tip portion into said second tip portion,

and said second tip portion disposed in said movable valve member bore and having an extension dimension greater than its relaxed extension dimension and a transverse dimension less than its relaxed transverse dimension so that said tip securely engages said wall portions due to said second tip portions's tendency to return toward its normal state.

2. The valve of claim 1 wherein said first tip portion is generally annular and has a convex transverse cross section, wherein sard fixed orifice rs surrounded by an unobstructed surface,

and wherein said first tip portion engages said unobstructed surface around said fixed orifice to close said orifice to flow and said movable member has generally unobstructed movement toward said orifice substantially throughout the extent of the projection of said first tip portion, the entire sealing engagement between said tip and said unobstructed surface being spaced from said orifice so that the closure of said orifice is effected throughout said range of unobstructed movement without said first tip portion protruding into said orifice.

3. The valve of claim 2 wherein said bore and second tip portions are cylindrical and said transverse dimensions are diameters.

4. The valve of claim 3 wherein said means for moving said valve member comprises a float mechanism.

5. The valve of claim 1 wherein said bore and second tip portions are cylindrical and said transverse dimensions are diameters.

6. A flow control valve comprising, in combination,

a valve member including a fixed orifice through which flow occurs,

a movable valve member having an end,

said tip including a first portion projecting from said end and a second portion having a transverse dimension and an extension generally normal to said transverse dimension thereof, said transverse dimension being generally uniform along the extension of said tip and said tip characterized by having a normal relaxed state wherein said transverse dimension thereof is greater than said transverse dimension of said bore and said tip being stretchable along its extension to reduce the tip transverse dimension and tending to return to its normal relaxed state from said stretched state when released whereby stretching of said tip extension reduces said transverse tip dimension for insertion in said bore and release of said tip causes said tip to expand in the direction of its transverse dimension to engage said wall portions along the entire extension of said tip in said movable valve member bore,

and said second tip portion disposed in said bore and having an extension dimension greater than its relaxed extension dimension and a transverse dimension less than its relaxed transverse dimension so that said tip securely engages said wall portions due to said second tip portion's tendency to return toward its normal state and generally along the entire extension of said tip in said movable valve member bore.

i t i t

Claims

1. A flow control valve comprising, in combination, a valve member including a fixed orifice through which floW occurs, a movable valve member having an end, a generally resilient tip carried on said end and movable with said valve member, means for moving said valve member relative to said orifice to move said tip selectively into and out of closing engagement with said orifice, means defining a bore in said end of said movable valve member with said bore having generally opposed wall portions defining a transverse dimension, said tip including a first portion projecting from said end and a second portion having a transverse dimension and an extension generally normal to said transverse dimension thereof, said tip characterized by having a normal relaxed state wherein said transverse dimension thereof is greater than said transverse dimension of said bore and said tip being stretchable along its extension to reduce the tip transverse dimension and tending to return to its normal relaxed state from said stretched state when released whereby stretching of said tip extension reduces said transverse tip dimension for insertion in said bore and release of said tip causes said tip to expand in the direction of its transverse dimension to engage said wall portions, means defining an interior bore in said resilient tip extending through said first tip portion into said second tip portion, and said second tip portion disposed in said movable valve member bore and having an extension dimension greater than its relaxed extension dimension and a transverse dimension less than its relaxed transverse dimension so that said tip securely engages said wall portions due to said second tip portions''s tendency to return toward its normal state.

2. The valve of claim 1 wherein said first tip portion is generally annular and has a convex transverse cross section, wherein said fixed orifice is surrounded by an unobstructed surface, and wherein said first tip portion engages said unobstructed surface around said fixed orifice to close said orifice to flow and said movable member has generally unobstructed movement toward said orifice substantially throughout the extent of the projection of said first tip portion, the entire sealing engagement between said tip and said unobstructed surface being spaced from said orifice so that the closure of said orifice is effected throughout said range of unobstructed movement without said first tip portion protruding into said orifice.

6. A flow control valve comprising, in combination, a valve member including a fixed orifice through which flow occurs, a movable valve member having an end, a generally resilient tip carried on said end and movable with said valve member, means for moving said valve member relative to said orifice to move said tip selectively into and out of closing engagement with said orifice, means defining a bore in said end of said movable valve member with said bore having generally opposed wall portions defining a transverse dimension, said tip including a first portion projecting from said end and a second portion having a transverse dimension and an extension generally normal to said transverse dimension thereof, said transverse dimension being generally uniform along the extension of said tip and said tip characterized by having a normal relaxed state wherein said transverse dimension thereof is greater than said transverse dimension of said bore and said tip being stretchable along its extension to reduce the tip transverse dimension and tending to return to its normal relaxed state from said stretched state when released whereby stretching of said tip extension reduces said transverse tip dimensioN for insertion in said bore and release of said tip causes said tip to expand in the direction of its transverse dimension to engage said wall portions along the entire extension of said tip in said movable valve member bore, and said second tip portion disposed in said bore and having an extension dimension greater than its relaxed extension dimension and a transverse dimension less than its relaxed transverse dimension so that said tip securely engages said wall portions due to said second tip portion''s tendency to return toward its normal state and generally along the entire extension of said tip in said movable valve member bore.