PRESSURE TANK SAFETY VENT SYSTEM

• US 3,845,876 A
• Filed: 10/01/1973
• Issued: 11/05/1974
• Est. Priority Date: 10/01/1973
• Status: Expired due to Term

• Current Assignee: ACF Industries Holding Corporation (Icahn Associates Holding LLC)
• Original Assignee: Dwaine G. Souchek, Robert F. Needham
• Inventors: Needham, Robert F., Souchek, Dwaine G.
• Primary Examiner(s): Petrakes, John
• Application Number:
  US05/402,523
• Time in Patent Office: 400 Days
• Field of Search: 220/44R,44D,89A,27 137/494,514.3,514.5,514.7,68,70,71,117,505.11,514
• US Class Current: 220/203.29
• CPC Class Codes: B65D 90/34 Venting means vehicle fuel tanks characterised by venting means B60K15/035
• CPC Class Codes: F16K 24/04 for venting only F16K24/02 takes precedence
• CPC Class Codes: Y10T 137/1789 Having pressure responsive valve
• CPC Class Codes: Y10T 137/7781 With separate connected fluid reactor surface
• CPC Class Codes: Y10T 137/785 With retarder or dashpot
• CPC Class Codes: Y10T 137/7852 End of valve moves inside dashpot chamber

Abstract

In accordance with the present invention a pressure tank safety vent system is provided comprising a vent member mounted in a fixed housing. The vent member is hollow and is in fluid communication with the tank. It has at least one port adapted to vent the tank pressure. A resilient assembly is provided which restrains movement of the vent member within the fixed housing. The resilient assembly includes at least two chambers, at least one of which contains a vent controlling fluid. The chambers are in fluid communication by means of at least one vent controlling channel. In the event that pressure build-up within the tank lasts sufficiently long to transport at least a portion of the fluid from one chamber to the other chamber, the vent member will move sufficiently within the fixed housing to vent the tank pressure. In the event that an insufficient amount of fluid is transferred, such as during a surge in the tank, for example, caused by coupling impacts on a railway tank car, the vent member will not vent the system and in a preferred embodiment will return to generally its original position due to the spring constant of the resilient means and/or gravity and the fluid will return to the original chamber. The flow of fluid from one chamber to the other determines the time lapse between pressure build-up and venting. The time may be controlled by the viscosity of the fluid and the cross sectional area of the vent controlling channel. The spring constant of the resilient means, viscosity of the fluid, the size of the channel and the volume and pressure within the chambers may be varied to meet different pressure and/or surge conditions encountered in different applications. A piston and cylinder arrangement may be used to define the vent controlling channel. Displacement of the vent member can be controlled by providing a tapered piston, or providing ports between said first and second chambers which are closed off by a portion of the moving vent member. In one embodiment the vent member may vent the pressure build-up into a vent chamber and a burst disk is provided between the vent chamber and the atmosphere. In venting to atmosphere appropriate means, such as a cap, may be provided to direct the vented material away from personnel which may be in the area of the pressure tank.

Claims

1. A pressure tank safety vent system comprising:

a hollow housing adapted to be in communication with an opening in said pressure tank;

a vent member mounted within the hollow portion of said housing;

said vent member having a vent opening therein in communication with the opening in said housing, and having at least one port in communication with said vent opening;

said vent member being movable within said hollow portion between first and second positions, in said first position said housing preventing said port from venting said pressure tank and a second position wherein said port is adapted to vent said pressure tank;

said housing further having mounted therein a resilient assembly comprising;

resilient means biased into an extended position;

first and second chambers at least one of which contains a vent controlling fluid, said chambers being in fluid communication by means of at least one vent controlling channel;

said resilient assembly being in mechanical engagement with at least a portion of said housing;

whereby during a pressure build-up in said pressure tank, the tank pressure is applied to said resilient assembly and said vent controlling fluid will pass through said vent controlling channel, and in the event the pressure build-up continues for a time sufficient to transfer a substantial portion of said fluid from said first channel to said second channel, said vent member will move into said second position and vent said pressure tank.

2. A pressure tank safety vent system according to claim 1 wherein in the event that said pressure build-up is of a sufficiently short duration as to transfer an insufficient amount of fluid from said first chamber to said second chamber to move said vent member to said second position, said vent member will return to approximately its original position.

3. A pressure tank safety vent system according to claim 2 wherein said resilient means comprises a bellows.

4. A pressure tank safety vent system according to claim 2 wherein said fluid is a liquid having a viscosity of 500 to 2,000 centistokes.

5. A pressure tank safety vent system According to claim 4 wherein the total area of said channels is from about 0.01 to about 1 square inch.

6. A pressure tank safety vent system according to claim 5 wherein the total area of said opening is from about 0.02 to about 0.1 square inch.

7. A pressure tank safety vent system according to claim 6 wherein said liquid has a viscosity of from about 750 to about 1, 500 centistokes.

8. A pressure tank safety vent system according to claim 7 wherein said liquid is silicone oil.

9. A pressure tank safety vent system according to claim 2 wherein said resilient means comprises an elastomeric housing.

10. A pressure tank safety vent system according to claim 2 wherein a bushing is provided in said housing and wherein said piston is movable along said bushing.

11. A pressure tank safety vent system according to claim 2 wherein said channel is defined by clearance between a piston and a portion of said first chamber.

12. A pressure tank safety vent system according to claim 11 wherein said first chamber and said piston are movable with respect to the other.

13. A pressure tank safety vent system according to claim 11 wherein said first and second chambers are located within said resilient means.

14. A pressure tank safety vent system according to claim 11 wherein said piston is fixed and said first chamber is movable with respect thereto.

15. A pressure tank safety vent system according to claim 11 wherein said piston is tapered.

16. A pressure tank safety vent system according to claim 11 wherein check valve ports are provided between said first chamber and said second chamber.

17. A pressure tank safety vent system according to claim 11 wherein a plurality of ports are provided between said first and second chambers and wherein selected ports are closed off as said vent member moves toward said second position.

18. A pressure tank safety vent system according to claim 17 wherein said piston is hollow and is provided with a plurality of ports and wherein as said first chamber rises it closes off selected ones of said ports.

19. A pressure tank safety vent system according to claim 17 wherein a greater force is required to move said vent member a given additional distance as additional ports are closed off.

20. A pressure tank safety vent system according to claim 11 wherein a third chamber is defined between said first and second chambers.

21. A pressure tank safety vent system according to claim 20 wherein said third chamber is defined by a cap mounted upon said first chamber.

22. A pressure tank safety vent system according to claim 21 wherein said piston is tapered in the vicinity of said third chamber and wherein a constant force is required to move said first chamber with respect to said piston but a greater force is required to move said third chamber with respect to said piston.

23. A pressure tank safety vent system according to claim 1 wherein a plurality of vent controlling channels are provided between said first and second channels.

24. A pressure tank safety vent system comprising:

a hollow housing adapted to be in communication with an opening in said pressure tank;

a vent member mounted within the hollow portion of said housing;

said vent member having a vent opening therein in communication with the opening in said housing, and having at least one port in communication with said vent opening;

said vent member being movable within said hollow portion between first and second positions, in said first position said housing preventing said port from venting said pressure tank and a second position wherein said port is adapted to vent said pressure tank to the atmosphere;

said housing further having mounted therein a resilient assembly comprising;

resilient means biased into an extended position;

first and second chambers at least one of which contains a vent controlling fluid, said chambers being in fluid communication by means of at least one vent controlLing channel;

said resilient assembly being in mechanical engagement with at least a portion of said housing;

whereby during a pressure build-up in said pressure tank, the tank pressure is applied to said resilient assembly and said vent controlling fluid will pass through said vent controlling channel, and in the event the pressure build-up continues for a time sufficient to transfer a substantial portion of said fluid from said first channel to said second channel, said vent member will move into said second position and vent said pressure tank to the atmosphere.

25. A pressure tank safety vent system according to claim 24 wherein in the event that said pressure build-up is of a sufficiently short duration as to transfer an insufficient amount of fluid from said first chamber to said second chamber to move said vent member to said second position, said vent member will return to approximately its original position.

26. A pressure tank safety vent system according to claim 25 wherein said resilient means is provided with a spring to assist the resilient means to return the original position.

27. A pressure safety vent system according to claim 25 wherein said housing is made in at least two parts comprising an upper housing and a lower housing and a sealing means is provided between said housing.

28. A pressure tank safety vent system according to claim 25 wherein said resilient means is mounted upon said vent member and said reservoir is mounted above said resilient means.

29. A pressure tank safety vent system according to claim 25 wherein reservoir is mounted upon said vent member and said resilient means is mounted above said reservoir and wherein said resilient means engages a portion of said housing.

30. A pressure tank safety vent system according to claim 25 wherein a cover is affixed to said vent member to direct the flow of vented material.

31. A pressure tank safety vent system according to claim 25 wherein said vent member is provided with a flange to maintain said resilient assembly.

32. A pressure tank safety vent system according to claim 31 wherein means are also provided on said housing to maintain engagement of said resilient assembly.

33. A pressure tank safety vent system according to claim 32 wherein said means comprise at least one protrusion.

34. A pressure tank safety vent system according to claim 25 wherein sealing means is provided between said vent member and said housing.

35. A pressure tank safety vent system according to claim 34 wherein said sealing means is an O-ring.

36. A pressure tank safety vent system comprising:

a hollow housing adapted to be in communication with an opening in said pressure tank;

a vent member mounted within the hollow portion of said housing;

said vent member having a vent opening therein in communication with the opening in said housing, and having at least one port in communication with said vent opening;

said vent member being movable within said hollow portion between first and second positions, in said first position said housing preventing said port from venting said pressure tank and a second position wherein said port is adapted to vent said pressure tank into a vent chamber;

said housing further having mounted therein a resilient assembly comprising;

resilient means biased into an extended position;

first and second chambers at least one of which contains a vent controlling fluid, said chambers being in fluid communication by means of at least one vent controlling channel;

said resilient assembly being in mechanical engagement with at least a portion of said housing;

a burst disk mounted in said vent chamber adapted upon bursting to vent said vent chamber to the atmosphere;

whereby during a pressure build-up in said pressure tank, the tank pressure is applied to said resilient assembly and said vent controlling fluid will pass through said vent controlling channel, and in the event the pressure build-up continues for a time sufficienT to transfer a substantial portion of said fluid from said first channel to said second channel, said vent member will move into said second position and vent said pressure tank into said vent chamber, and whereby in the event the pressure in said vent chamber exceeds the design pressure of said burst disk, said burst disk will burst and vent said vent chamber to the atmosphere.

37. A pressure tank safety vent system according to claim 36 wherein in the event that said pressure build-up is of a sufficiently short duration as to transfer an insufficient amount of fluid from said first chamber to said second chamber to move said vent member to said second position, said vent member will return to approximately its original position.

38. A pressure tank safety vent system comprising:

vent means connected to said tank and operable by a predetermined pressure within said tank to vent said tank; and

resilient time delay means operatively connected with said vent means, said resilient time delay means comprising at least two chambers separated by a passageway, one of said chambers containing a fluid for delaying opening of said vent means to vent said tank until said predetermined pressure has existed for a predetermined period of time to transfer at least a portion of said fluid from one of said chambers to the other through said passageway, whereby said vent means is not operative to vent said tank by pressure surges of a time duration less than said predetermined period of time.

39. A pressure tank safety vent system according to claim 38 wherein in the event of a pressure surge said resilient time delay means absorb at least some energy from said pressure surge.

40. A pressure tank safety vent system according to claim 39 wherein said resilient time delay means comprises a bellows chamber and a reservoir, and fluid passes from said bellows chamber into said reservoir.

41. A pressure tank safety vent system according to claim 39 wherein in said resilient time delay means at least one of said chambers comprises a cylinder having a piston movable with respect thereto adapted to absorb energy from said surges.

42. A pressure tank safety vent system according to claim 38 wherein said vent means comprises at least one rupturable member.

43. A pressure tank safety vent system according to claim 38 wherein said vent means comprises at least one port.