WO2018027270A1

WO2018027270A1 - Pressure relief valve

Info

Publication number: WO2018027270A1
Application number: PCT/AU2017/050841
Authority: WO
Inventors: Hercules Lourens
Original assignee: Elube Pty Ltd
Priority date: 2016-08-11
Filing date: 2017-08-10
Publication date: 2018-02-15
Also published as: AU2017309818A1

Abstract

The present invention is directed broadly to a pressure relief valve (10) for a centralised lubrication system. The pressure relief valve (10) includes a valve body (11) having a first through passage (12), and a second passage (15) extending from the first passage (12). The second passage (15) includes a valve seat (18), and a first narrow portion (19) located between the valve seat (18) and the first passage (12). The second passage (15) also includes an enlarged fluid chamber (20) adjacent the valve seat (18). The valve body (11) includes an elongate bore (21) and slidably mounted in the bore (21) is a moveable valve member (17). The valve member (17) includes a valve head (22) that seats with the valve seat (18) to prevent the flow of the pressurised through the narrow portion (19). Attached to the end of the valve member (17) is a cam member (31) formed integral with a handle (29). The cam member (31) is pivotally attached to the moveable member (17) so that when the handle (29) is manually moved angularly toward the valve body (11) the moveable valve member (17) is unseated from the valve seat (18). This provides pressure relief wherein fluid can flow through the narrow portion (19) to be delivered to a vent opening (38) via the fluid chamber (20) and a vent passage (28).

Description

PRESSURE RELIEF VALVE

Technical Field

[0001 ] The present invention relates broadly to pressure relief valves and relates more particularly, although not exclusively, to manually operable pressure relief valves for lubricants.

Background of Invention

[0002] Centralised grease lubrication systems are set up to relieve pressure should pressure become excessive, and to ensure that the system is not left pressurised. However, these centralised grease lubrication systems have the disadvantage that frequently the components fail, leaving the system pressurised, and not relieving excessive pressure.

Summary of Invention

[0003] According to the present invention there is provided a manually operable pressure relief valve comprising:

a valve body including a first passage extending between inlet and outlet openings in the valve body, the first passage adapted to receive a pressurised fluid;

a second passage extending from the first passage to a vent opening in the valve body, the second passage including a valve seat;

a moveable valve member operatively coupled to the valve body for movement between a closed position wherein said valve member seats with the valve seat to prevent flow of the pressurised fluid through the second passage, and an open position wherein said valve member unseats from the valve seat permitting the flow of said fluid through the second passage to the vent opening;

biasing means operatively coupled to the moveable valve member to bias it into the closed position; and

a cam member operatively coupled to the moveable valve member whereby manual actuation of the cam member effects movement of the moveable valve member toward the open position permitting the flow of the pressurised fluid through the second passage to the vent opening. [0004] Preferably the pressure relief valve includes a handle integral with the cam, the handle adapted to be manually actuated for opening of the moveable valve member. More preferably the cam member is pivotally coupled to the moveable valve member about a cam pivot axis. Still more preferably the moveable valve member has a longitudinal axis, and the cam pivot axis is disposed transverse relative to said longitudinal axis.

[0005] Preferably the cam member includes a cam surface extending angularly about the cam pivot axis between a first angular position and a second angular position, the cam surface increasing in its radial separation from the cam pivot axis from the closed position to the open position.

[0006] Preferably the second passage includes a fluid chamber located adjacent the valve seat, said fluid chamber designed to receive the pressurised fluid from the first passage on opening of the moveable valve member.

[0007] Preferably the biasing means is a spring designed to maintain closure of the valve member in its closed position up to a predetermined pressure of the pressurised fluid in the first passage. More preferably the spring is designed on manual actuation of the cam member to release the moveable valve member from the closed position into which it is biased toward the open position.

[0008] Preferably the moveable valve member includes an elongate stem at one end having a valve head shaped to seat with the valve seat, and at an opposite end coupled to the cam member. More preferably the elongate stem includes an annular flange proximal said one end, said flange designed to reciprocate within an elongate bore in the valve body on movement of the moveable valve member between the closed and open positions. Still more preferably the spring locates within the elongate bore and bears upon the annular flange in biasing the moveable valve member closed. Brief Description of Drawings

[0009] In order to achieve a better understanding of the nature of the present invention a preferred embodiment of a pressure relief valve will now be described, by way of example, with reference to the accompanying drawings in which:

Figure 1 is a schematic isometric view of a manually operable pressure relief valve for a centralised lubrication system;

Figure 2 is a schematic section side elevation of the pressure relief valve of Figure 1 in a closed position;

Figure 3 is a schematic section side elevation of the pressure relief valve of figures 1 and 2 in an open position; and

Figure 4 is a schematic side elevation of the valve body of the pressure relief valve of the preceding Figures.

Detailed Description

[0010] In the accompanying drawings there is depicted one embodiment of a pressure relieve valve 10 for a centralised lubrication system according to the present invention. The pressure relief valve 10 includes a valve body 1 1 having a first through passage 12. The first passage 12 extends through the valve body 1 1 between body inlet and outlet openings 13 and 14 respectively. Extending from the first passage 12 is a second passage 15, also formed within the valve body 1 1 . The second passage 15 extends from the first passage 12 to a body opening 16 which is threaded. The first passage 12 may include a branch passage 40.

[001 1 ] The second passage 15 includes a valve seat 18. The second passage 15 of this example also includes a first narrow portion 19 located between the valve seat 18 and the first passage 12. The second passage 15 also includes an enlarged fluid chamber 20 adjacent the valve seat 18. The valve body 1 1 includes an elongate bore 21 and slidably mounted in the bore 21 is a moveable valve member 17. The valve member 17 includes a valve head 22 that is tapered to seat with the valve seat 18 to prevent the flow of the pressurised fluid through the narrow portion 19. [0012] The moveable valve member 17 includes an annular flange 23 and an elongate stem 24 that projects through the body opening 16 so as to extend outside the valve body 1 1 . The stem 24 slides within a nut 25 that threadably engages the body opening 16 so as to be fixed to the valve body 1 1 . Seals 26 slidably locate about the external surface of the moveable valve member 17 to seal the nut 25 about the elongate stem 24. Located between the nut 25 and the annular flange 23 is an annular cavity 27 that receives biasing means in the form of a spring 41 . The spring 41 is maintained in a compressed configuration, and bears against the nut 25 and annular flange 23 to urge the moveable valve member 17 into seated engagement with the seat 18.

[0013] As seen in Figure 4, extending from the fluid chamber 20 is a vent passage 28 which extends to a vent opening 38. The fluid chamber 20 is designed on opening of the valve member 17 to receive pressurised fluid from the first passage 12 via the narrow portion 19. The pressurised fluid is reduced in pressure within the relatively large volume fluid chamber 20 prior to its release to the vent opening 38 via the vent passage 28.

[0014] Attached to the end extremity of the moveable valve member 17, most remote from the valve head 22, is a cam member 31 . The cam member 31 is in this example integral with a handle 29 having an elongated lever portion 30 extending from the cam member 31 . The cam member 31 is pivotally attached to the end extremity of the moveable valve member 17 by means of a pivot pin 32. The pivot pin 32 provides a cam pivot axis 33 about which the handle 29 can pivot. The moveable valve member 17 or in this case the elongate stem 24 has a longitudinal axis 34 that is oriented transverse (preferably perpendicular) relative to the cam pivot axis 33.

[0015] The cam member 31 has a cam surface 35 that extends from a first angular position 36 to a second angular position 37. The radial separation of the cam surface 35 from the cam pivot axis 33 increases from the first position 36 to the second position 37. On manual actuation of the cam member 31 via the handle 29, the cam surface 35 bears against the nut 25.

[0016] In operation of the described preferred embodiment of the pressure relief valve 10, when the handle or trigger 29 is manually moved angularly in the direction 39 toward the valve body 1 1 about the cam pivot axis 33, the moveable valve member 17 is unseated from the valve seat 18. Accordingly, fluid such as lubricant can flow through the narrow portion 19 to be delivered to the vent opening 38 via the fluid chamber 20 and the vent passage 28. This flow of fluid through the second passage 15 serves to relieve pressure in the first passage 12. The valve 10 is also automatically actuated if pressure in the first passage 12 exceeds a pressure determined by the compression of the spring 41 . The moveable valve member 17 is thus unseated from the valve seat 18, again allowing the release of pressurised fluid from the first passage 12 to the vent opening 38 via the second passage 15. In one embodiment the pressure relief valve 10 is designed to automatically activate at a pressure of around 6,000 to 7,000 psi. It is understood that the size of the narrow passage 19 may need to be increased to achieve this relatively high activation or release pressure. The manual opening of the valve 10 serves as a primary release and the automatic opening at the predetermined pressure functions as a secondary release.

[0017] Now that a preferred embodiment of a pressure relief valve has been described it will be apparent to those skilled in the art that it has the following advantages:

1 . the pressure relief valve provides pressure relief in for example centralised grease lubrication systems by manual activation of the valve;

2. the pressure relief valve maintains closure under normal operating conditions and pressures whilst in the absence of manual activation allowing automatic activation at a predetermined threshold pressure;

3. the pressure relief valve includes flow passages hydraulically designed to permit the safe relief of pressurised fluid on manual opening of the valve;

4. the pressure relief valve including the cam member can be released with relative ease by manual gripping, utilising the mechanical advantage of the cam member.

[0018] Those skilled in the art will appreciate that the invention as described herein is susceptible to variations and modifications other than those specifically described. For example, the relative sizes and orientations of the first and second passages may vary provided the pressure relief valve permits the release of pressure on manual opening of the valve. The cam member may vary in its shape and/or orientation relative to the remainder of the valve provided it permits manual opening for pressure relief with its inherent mechanical advantage. All such variations and modifications are to be considered within the scope of the present invention the nature of which is to be determined from the foregoing description.

Claims

1 . A manually operable pressure relief valve comprising:

a cam member operatively coupled to the moveable valve member whereby manual actuation of the cam member effects movement of the moveable valve member toward the open position permitting the flow of the pressurised fluid through the second passage to the vent opening.

2. A pressure relief valve as claimed in claim 1 including a handle integral with the cam, the handle adapted to be manually actuated for opening of the moveable valve member.

3. A pressure relief valve as claimed in either of claims 1 or 2 wherein the cam member is pivotally coupled to the moveable valve member about a cam pivot axis.

4. A pressure relief valve as claimed in any one of the preceding claims wherein the moveable valve member has a longitudinal axis, and the cam pivot axis is disposed transverse relative to said longitudinal axis.

5. A pressure relief valve as claimed in any one of the preceding claims wherein the cam member includes a cam surface extending angularly about the cam pivot axis between a first angular position and a second angular position, the cam surface increasing in its radial separation from the cam pivot axis from the closed position to the open position.

6. A pressure relief valve as claimed in any one of the preceding claims wherein the second passage includes a fluid chamber located adjacent the valve seat, said fluid chamber designed to receive the pressurised fluid from the first passage on opening of the moveable valve member.

7. A pressure relief valve as claimed in any one of the preceding claims wherein the biasing means is a spring designed to maintain closure of the valve member in its closed position up to a predetermined pressure of the pressurised fluid in the first passage.

8. A pressure relief valve as claimed in claim 7 wherein the spring is designed on manual actuation of the cam member to release the moveable valve member from the closed position into which it is biased toward the open position.

9. A pressure relief valve as claimed in any one of the preceding claims wherein the moveable valve member includes an elongate stem at one end having a valve head shaped to seat with the valve seat, and at an opposite end coupled to the cam member.

10. A pressure relief valve as claimed in claim 9 wherein the elongate stem includes an annular flange proximal said one end, said flange designed to reciprocate within an elongate bore in the valve body on movement of the moveable valve member between the closed and open positions.

1 1 . A pressure relief valve as claimed in claim 10 wherein the spring locates within the elongate bore and bears upon the annular flange in biasing the moveable valve member closed.