WO1982003259A1

WO1982003259A1 - Spring-loaded valve

Info

Publication number: WO1982003259A1
Application number: PCT/US1982/000326
Authority: WO
Inventors: Devices Inc Control; Michael J Purvis
Original assignee: Control Devices LLC
Current assignee: Control Devices LLC
Priority date: 1981-03-23
Filing date: 1982-03-15
Publication date: 1982-09-30
Anticipated expiration: 1983-09-23
Also published as: JPS58500373A; CA1187379A; IT8220277A0; FR2502282B3; IT1150710B; GB2107832A; FR2502282A1; GB2107832B

Abstract

This invention relates to the field of spring-loaded check valves. Prior check valves have required a great number of parts and thus complicated assembly steps were required; this rendered inspection of the check valve more difficult. This invention comprises a check valve which has a minimum number of parts, which is easy to assemble and whose valve member and seat are readily inspected without disassembly of the valve. The check valve includes a coil spring (29) which functions not only to bias the valve member (33) toward its seat (25) but also to retain the valve member in assembly with the valve.

Description

SPRING-LOADED VALVE

Background of the Invention

This invention relates to valves, and more par¬ ticularly to spring-loaded air valves. The invention is concerned, in one aspect, with a check valve which^" in use is connected between an air compressor and a storage tank for compressed air received from the compressor to check the return of air from the tank back to the compressor. Commonly, the outlet end of the check valve is threaded into the inlet of the tank, an air line being interconnected between the air com¬ pressor and the valve inlet. A valve of this invention is especially suited to this type of use, that is, where the outlet end of the valve is threaded into an inlet of a tank. In another aspect, the invention is concerned with a safety valve for venting air from means holding air under pressure when the pressure rises above a pre¬ determined level.

Summary of the Invention

Among the several objects of this invention may be noted the provision of an improved spring-loaded valve, e.g., a check valve or a safety valve, of simpli¬ fied and economical construction; the provision of such a valve which has a minimum number of parts and which is easy to assemble; the provision of such a check valve whose valve member and its seat are readily inspected without disassembly of the valve; the provision of such a

OMPI check valve in which the moving parts are mounted unen¬ closed at the outlet end of the valve for low cost; and the provision of such a check valve which may be in¬ stalled with its unenclosed moving parts projecting into an enclosed, protected space, such as the inlet of a com¬ pressed air storage tank or the like; and the provision of such a safety valve which may be initially readily adjusted as to the opening pressure and then protected against change in adjustment.^" Briefly summarized, a valve of this invention comprises a valve body having a passage extending there¬ through to an outlet end. A coil spring is secured to the outside of the valve body at its outlet end and ex¬ tends endwise from the body. A valve member is disposed within the spring and is adapted to close the outlet end of the passage, there being means at the downstream end of the spring for engaging the valve member and confining it within the spring. The spring is in tension and the stated means for engaging and confining the spring normally seats the valve member against the valve body to close the outlet end of the passage, with the valve member being adapted to open against the bias of the spring.

Other objects and features will be in part ap- parent and in part pointed out hereinafter.

Brief Description of the Drawings

Fig. 1 is a longitudinal section of a check valve of the present invention installed in a tapped hole such as the inlet of a compressed air tank, shown with the valve closed; Fig. 2 is a section similar to Fig. 1 showing the Fig. 1 valve open;

Fig. 3 is an end view of the outlet end of the Fig. 1 valve; Fig. 4 is a longitudinal section of a safety valve of the present invention, showing the valve closed; and

Fig. 5 is a transverse section on line 5—5 of Fig. 4. Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Description of the Preferred Embodiment

Referring first to Figs. 1-3 of the drawings, a check valve of this invention, designated in its entirety by the numeral 1, is shown installed in a tapped hole such as the threaded inlet 3 in the wall 5 of a storage tank, such as a storage tank for compressed air supplied from an air compressor via the check valve 1. The in- terior surface of the storage tank wall is designated 7 and the exterior surface is designated 9.

As shown, the check valve 1 comprises an e- longate valve body 11 of metal, such as brass, having an axial passage 13 extending therethrough from its inlet end 15 to its outlet end 17. The inlet end of the body has external threads 19 for connection of a line from an air compressor, for example, and has a hexagonal head 21 downstream of threads 19 which will accept a wrench. Downstream of the hexagonal head, the body has an externally-threaded cylindric portion or shank 23 for threading into inlet 3 of the storage tank. At its outlet end, downstream of threaded cylindric portion 23, the valve body has a reduced-diameter cylindric extension 25 of lesser diameter than inlet 3. The extension has a relatively coarse external screw thread 27 providing a circumferential groove.

A coil spring 29 of cylindrical form is secured to the outside of the reduced-diameter extension 25 of the valve body and extends endwise from the body (down¬ stream therefrom) coaxial with the body. The diameter of the spring is less than that of the storage tank inlet 3 and large enough snugly to fit over extension 25 and interengage with its screw thread.27. The diameter of the spring wire forming the spring is relatively small, whereby the coils of the spring are relatively deeply engaged in the thread 27 firmly to secure the spring to the valve body. As shown in Fig. 3, the spring has an inwardly spiraling convolution 31 at its downstream end generally in a transverse plane of the spring forming a radially inwardly extending portion of the spring which partially closes its outer (downstream) end.

A valve member 33, preferably though not neces¬ sarily of a suitable plastic, such as glass-fiber-filled polytetrafluoroethylene, for example, is disposed concen¬ trically within the spring between the end 17 of the ex¬ tension 25 of the valve body, which constitutes the valve seat of the check valve, and the inwardly spiraling convolution 31 of the spring, being confined within the spring by the convolution. The valve member is shown in the drawings as a relatively thick disc, but members of

^0s_l other shapes may be used, for example a ball. The spring is of such length that, as assembled with the valve body with the valve member within the spring between the seat 17 and the spring end convolution 31, the spring is placed in tension by the presence of the valve member. Convolution 31 engages the outside (the downstream side) of the valve member and, as shown in Fig. 1, normally seats the valve member against the outlet end or valve seat 17 of the valve body, closing the outlet end of passage 13. As shown in Fig. 2, the valve member 33 opens against the bias of the spring when the pressure upstream of the valve member (within passge 13) exceeds the pressure downstream of the valve member by an amount which exceeds the spring tension. The check valve of this invention as described above is inexpensive and easy to assemble, having a mini¬ mum number of parts (three parts - the body, spring and valve member) . Because the moving parts of the valve (spring 29 and valve member 33) are not enclosed by the valve body, they are readily inspected without disas¬ sembly of the valve. The valve is especially suited to uses in which the outlet end of the valve is threaded into an inlet in a storage tank or other enclosed space, the moving parts being protected (by being enclosed in the tank) against dirt and damage. It also appears that the valve is characterized by lower pressure losses thereacross in comparison with prior valves having a spring retainer.

Referring to Figs. 4 and 5 of the drawings, a safety valve of this invention, designated in its en¬ tirety by the numeral 35, comprises an elongate tubular valve body 37 of metal, such as brass, having an axial passage 39 therethrough from its inlet end 41 to its outlet end 43. The body has a hexagonal head 45 inter¬ mediate its ends for application of a wrench to turn the valve. Upstream of the head, the body has a first externally-threaded portion or shank 47. Downstream of the head, the body has a second cylindric portion 49 having an annular external flange 51 spaced closely adjacent the head and external threads 53 downstream of the flange. At its outer end, cylindric portion 49 is formed with a circular internal recess 55 having a valve seat 57 projecting downstream within the recess. The downstream end of seat 57 is upstream of the downstream end of cylindric portion 49. A coil spring 59 of cylindrical form is threaded on the screw thread 53 on the outside of cy¬ lindric portion 49 and extends endwise (downstream) therefrom coaxial with the body. The diameter of the spring wire forming the spring is relatively small, whereby the coils of the spring are relatively deeply engaged in the thread 53. As shown in Fig. 5, the spring has an inwardly spiraling convolution 61 forming a radi¬ ally inwardly extending portion of the spring at its downstream end generally in a plane transverse of the spring, constituting means for engaging and confining a valve member, generally designated 63, within the spring. Valve member 63 is comprised of a valve disc 65 having a central reduced-diameter cylindric portion 67 on its upstream side engageable in recess 55 on the outlet end of the valve body. Cylindric portion 67 has a central circular recess 69 in which is secured a disc¬ shaped resilient seal 71 (of a suitable elastomeric material) engageable with valve seat 57. The valve member has a stem 73 projecting downstream from valve disc 65 through the spring's end convolution 61. Stem 73 has a transverse hole 75 at its downstream end through which a ring pull 77 is looped.

A cover 79 is provided for the downstream end of valve 35 in the form of a cylindrical cap surrounding and spaced from cylindrical portion 49 of valve body 37, spring 59 and valve disc 65. ^' The cover is secured at its upstream end to the valve body by crimping its rim 81 under flange 51 between the flange and hexagonal head 45. The cover has a number of fluid (air) exit openings or ports 83 (e.g., four such ports) through its side wall and has a central opening 85 in its downstream end through which stem 73 projects.

In use, the safety valve 35 is threaded into a tapped hole in communication with a pressurized space and operates to limit the pressure of fluid within the space. As shown in Fig. 4, spring 59 normally biases valve disc 65 against valve seat 57. Valve member 63 opens against the bias of spring 59 when the pressure upstream of the valve disc exceeds atmospheric pressure (the pressure downstream of the valve disc) by an amount which exceeds the spring force. Pressurized fluid then escapes past the valve disc and through ports 83. In the manufacture of the valve, the spring 59 is initially threaded on the screwthread 53, before application of the cover or cap 79, to the point where the bias of the spring on the valve member 63 corresponds to the desired blow-off pressure. The spring holds itself in its

O PI adjusted position, thereby to maintain the pre-set blow- off pressure. The cover or cap is then applied, and functions to prevent tampering with the spring. The valve may be manually opened at any time by pulling on the ring 77.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying draw¬ ings shall be interpreted as illustrative and not in a limiting sense.

Claims

ClaimsWHAT IS CLAIMED IS:

1. A valve comprising a valve body having a passage extending therethrough to an outlet end, a coil spring secured to the outside of the valve body at said outlet end and extending endwise from the body, a valve member disposed within the spring adapted to close the outlet end of the passage, and means at the outer end of the spring engaging the valve member and confining it within the spring, the spring being in tension and said means acting to seat the valve member against the valve body to close, the outlet end of the passage, the valve member being adapted to open against the bias of the spring.

2. A valve as set forth in claim 1 wherein the coil spring is secured in a substantially circumferential groove in the outside of the valve body.

3. A valve as set forth in claim 2 wherein the substantially circumerential groove is formed by a screw thread.

4. A valve as set forth in claim 1 wherein the valve member comprises a member of circular outline dis¬ posed concentrically within the coil spring.

5. A valve as set forth in claim 1 wherein the valve member engaging and confining means comprises a radially inwardly extending portion of the spring at its outer end.

6. A valve as set forth in claim 1 wherein the valve member engaging and confining means comprises an inwardly-spiraling convolution of the spring at the outer end of the spring which partially closes that end of the spring.

7. A valve as set forth in claim 1 wherein the valve body has a cylindric portion having a reduced- diameter extension at its outlet end and wherein the coil spring is secured to the outside of said extension.

8. A valve as set forth in claim 7 wherein the cylindric portion of the valve body is externally threaded, whereby the valve body may be threaded into a tapped hole with the coil spring and valve member re- ceived in the hole.

9. A check valve for mounting in a threaded inlet of a storage tank or the like, comprising a valve body having a passage extending therethrough to an outlet end, a cylindric portion having a reduced-diameter ex- tension at the outlet end of the valve body, said cy¬ lindric portion being externally threaded for being threaded into said inlet with the extension received in the inlet and projecting into the storage tank, a coil spring of smaller diameter than said inlet secured to the outside of said reduced-diameter portion and extending endwise therefrom, the spring having an inwardly- spiraling convolution at its outer end which partially closes that end of the spring, and a valve member adapted to close the outlet end of the passage disposed within (continuing claim 9)

the spring between the downstream end of said extension and said inwardly-spiraling convolution, said convolution engaging said valve member and the spring being in ten¬ sion to bias the valve member against the downstream end of said extension to close the passage, the valve member being adapted to open against the bias of the spring.

10. A check valve as set forth in claim 9 wherein the valve member comprises a member of circular outline disposed concentrically within the coil spring.

11. A check valve as set forth in claim 9 wherein the coil spring is secured in a substantially circumferential groove in the outside of said extension.

12. A check valve as set forth in claim 11 wherein the substantially circumferential groove is formed by a screw thread.

13. A safety valve comprising a valve body having a passage extending therethrough to an outlet end and an externally screw-threaded cylindric portion at its outlet end, a coil spring threaded on the screw thread on said cylindric portion and extending endwise therefrom, a valve member disposed -within the spring adapted to close the outlet end of the passage, means at the outer end of the spring engaging the valve member and confining it within the spring, the spring being in tension and said means acting to seat the valve member against the valve body to close the outlet end of the passage, the valve member being adapted to open against the bias of the spring, and a cover for the spring secured to the valve body having at least one exit opening.

14. A safety valve as set forth in claim 13 wherein the valve member comprises a member of circular outline disposed concentrically within the coil spring.

15. A safety valve as set forth in claim 13 wherein the valve member engaging and confining means comprises a radially inwardly extending portion of the spring at its outer end.

16. A .safety valve as set forth in claim 15 wherein the valve member engaging and confining means comprises an inwardly-spiraling convolution of the spring at the outer end of the spring which partially closes that end of the spring.

17. A safety valve as set forth in claim 13 wherein the cover is in the form of a cap surrounding and spaced from said cylindric portion and spring and secured at its rim to the valve body.

18. A safety valve as set forth in claim 17 wherein said cylindric portion is formed at said outlet end with a recess receiving the valve member and with a valve seat projecting into the recess engageable by the valve member, and the valve member has a stem projecting out through said engaging and confining means and said cap. i

19. A safety valve comprising an elongate tubular valve body having a head intermediate its ends for application of a wrench, a first externally screw- threaded portion upstream of the head and a second cy- lindric portion downstream of the head, said cylindric (continuing claim 19) portion having an annular flange adjacent the head and being externally screw-threaded downstream of the flange, the valve body, being tubular, thereby having a passage therethrough from the outer end of said first portion to

10 the outer end of said cylindric portion, a coil spring threaded on the screw thread on said cylindric portion and extending endwise therefrom, a valve member disposed within the spring adapted to xylose the outlet end of the passage, the spring having an inwardly-spiraling convo- •15 lution at its outer end which partially closes that end of the spring and engages the valve member to confine it within the spring, the spring being in tension and said convolution acting to seat the valve member against the valve body to close the outlet end of the passage, the

20 valve member being adapted to open against the bias of the spring, a cap surrounding and spaced from said cy¬ lindric portion and from the spring, secured at its rim to said annular flange, the cap having at least one exit opening, and the valve member having a stem projecting

25 out through said convolution and said cap.

20. A safety valve as set forth in claim 19 further comprising a ring at the outer end of said stem downstream of the cap by means of which the valve member may be manually pulled to open the valve.

21. A safety valve as set forth in claim 19 wherein said cylindric portion is formed at said outlet end with a recess receiving the valve member and a valve seat projecting into the recess engageable by the valve

5 membe .

OMPI

22. A safety valve as set forth in claim 21 wherein said valve member has a central resilient seal engageable with said valve seat.

23. A safety valve as set forth in claim 19 wherein the cover is secured to the annular flange by crimping its rim under the flange .between the flange and the head.