AU2013245527A1 - Vent - Google Patents

Abstract

A vent with a double acting cylinder for holding the vent in one of an open or a closed condition. ............ .......... ............................. .............-............. ...................... ................... .................. ........................ ...... .... .... .......... ... ......................... ....................... ............ --.......................... ........ .............................. AN .............. ............ ..................... ............................................ ...................................... ................................................... ........................ .............................. ................... ............. .......................... ....................... ........... ................... .................... xx: ........................... ............ ... .................. ............. ........................ ................. ................................ . .............. .............. ..... ..... ..... . ............ .......... ............................ ............ x ............... ................ ............. ............... 'w X .............................. 0 KI\ X ......... AW .. .... .... X': .. ......... ................ ......................... ................................... ............................ ........... ............................. ............................... ........... ............... . ... .... ....... ............... ........ X X XX : .................................... ..... ...... ............................ ............................ ........................ .............. ............ ........... . X ................ ....... ............. .................................... ............. ..................... ................ ......... .

Description

- 1 VENT FIELD OF THE INVENTION [0001] The present invention relates to a vent particularly but not exclusively a vent for rapid ventilation of an enclosure in response to a trigger associated with a dangerous or hazardous event. BACKGROUND OF THE INVENTION [0002] One particular form of fast acting vent is used to rapidly ventilate a factory space in response to a fire or predicted fire, or smoke release. [0003] The vent includes a housing that accommodates a lid and a set of gas struts that act to force the lid open. To prime the vent, a single acting pneumatic cylinder is used to close the lid against the opening force of the struts until a locking device can be engaged to hold the lid closed. [0004] A release mechanism is connected to the locking device to release the lid when an above threshold condition occurs, such as an elevated temperature is reached, indicating a fire or the like. [0005] The release mechanism includes a thermal link, a cantilever arm and a release cable coupled to the locking mechanism. The cantilever arm is normally held in an elevated position in the vent housing but when the thermal link is broken the arm falls and pulls on the release cable, which frees the lid to rapidly open under pressure from the struts.

-2 OBJECT OF THE INVENTION [0006] The present invention seeks to provide an alternative vent. SUMMARY OF THE INVENTION [0007] In accordance with the invention, there is provided a vent with a double acting cylinder for holding the vent in one of an open or a closed condition. [0008] Preferably, the vent further includes a lid and a fulcrum arm for coupling the lid to a piston of the cylinder, with rollers mounted directly to the arm for rolling engagement in a channel of the lid. [0009] Preferably, the lid further includes gas struts connected between a frame of the vent and the lid, either side of the guide, for forced opening of the lid. [0010] Preferably, a seal is provided between a piston and a housing of the cylinder, the seal with positive pressure internally of the cylinder, in order to resist ingress of debris into the cylinder. [0011] In another aspect, there is provided a method of operating the above described, including applying air pressure to the cylinder to hold the vent in one of a closed or an opened condition. [0012] Preferably, the method further includes applying positive air pressure simultaneously to first and second air supply lines of the cylinder. [0013] Preferably, the method includes applying air pressure in order to prevent ingress of debris into the cylinder.

-3 [0014] Preferably, the method includes controlling air pressure applied to the supply lines to move the vent between a closed and opened condition. [0015] Preferably, the method includes allowing struts to force the vent into an open condition, as a failsafe measure, such as during an interruption in pressure supplied to the cylinder. [0016] In another aspect, there is provided a vent operating system including a vent, as described above, a pressure supply for supplying pressure to the cylinder and a control unit to control operation of the vent in accordance with the method described above. BRIEF DESCRIPTION OF THE DRAWINGS [0017] The invention is described in more detail with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic isometric view of a vent; Figure 2 is an exploded isometric view of a frame and cylinder of the vent; and Figure 3 is a diagrammatic isometric view of a vent operating system fitted to an abatement system. DETAILED DESCRIPTION OF THE DRAWINGS [0018] Referring firstly to Figure 1, a vent 1 is shown as including a frame 2 with a lid 3 attached to the frame 2 by hinges 4. Each hinge has an associated hinge plate 5, 6 to provide reinforcement to the lid 3. [0019] The central hinge plate 6 has a channel 7 that provides rolling engagement with an end 8 of a fulcrum arm 9 that is coupled to a cylinder 10.

-4 [0020] The cylinder 10 is mounted transversely of the frame 2, between cross beams 11. The fulcrum arm 9 is also mounted on an pin 12 that extends between the cross beams 11 so that extension or retraction of the cylinder causes the arm 9 to rotate on the pin 12 and drive the lid between a closed condition and an open condition, which is shown. [0021] Struts 13 are connected between the beams 11 and an upper mount 14 positioned either side of the channel 7. The struts 13 are pneumatic struts designed to urge the lid 3 into the open condition. [0022] During normal operation, the cylinder 10 is effective to counteract the force of the struts 13 and hold the lid 3 in a closed position such that the periphery 15 of the lid 3 abuts a seal 16 around the opening 17. The side sections 18 of the frame 2 are ramped so that, in the closed condition, the lid 3 is angled to allow for water run-off. [0023] A channel 19 allows for water run off along the centre of the frame 2. The vent 1 includes a second lid 3 for redundancy, positioned on an opposite side of the channel 18 with a mirror image arrangement of an associated cylinder 10 and struts 13. [0024] Both cylinders 10 are pneumatic and are powered by a common first line 22 and a common second line 23. [0025] The manner in which the cylinders 10 are operatively mounted to the beams 11 is described in further detail with reference to Figure 2. The cross beams 11 form a centre frame 24 constructed of and end plate 25 spanning between each of the beams 11. The centre frame 24 supports the struts 13, the fulcrum arm pin 12 and the cylinders 10, although only one of the cylinders will be described below, for the purposes of clarity. [0026] The cylinder 10 has a rear clevis 26 that receives a clevis pin 27 to pivotally couple the cylinder 10 to the beams 11. Spacers 28 are provided to distance the cylinder 10 from the beams 11 to avoid contact or interference from the beams as the cylinder 10 -5 pivots during use. The pin 27 is mounted in through holes 29 and a thrust bush 30 and circlip 31 secure the pin 27 in place. [0027] The fulcrum arm 9 is connected to a piston rod clevis 32 at a tail end 33 via thrust bushes 34. The pin 12 is in turn mounted through thrust bushes 35 into holes 36 in each beam 11 and held in place by a thrust bush 37 and circlip 38. [0028] The struts 13 are each mounted to the centre frame 24 by a gas strut nipple 39 that is fixed through the beam 11 by a nut 40. Each gas strut is mounted to the associated upper mount 14 by another nipple 41 and nut 42. [0029] The end 8 is connected into the channel by roller bearings 43 that are mounted directly to the arm 9 by a roller pin 44. The arm 9 and the roller bearings 43 are separated by a series of bushes 45. [0030] In use of the vent 1, the cylinder 10 is operated to move a piston 46 between a retracted and an extended position. This causes the fulcrum arm 4 to pivot about pin 12 and draw the associated lid 3 into a closed position. [0031] The cylinder is double acting so pressure can be applied through both lines 22, 23 in order to allow the cylinder to provide controlled movement of the lid back to the open position, if needed. The gas struts 13 are designed to automatically open the lid when the closing pressure provided by line 22 is reduced or terminated and multiple gas struts are provided for redundancy. However, the ability to open the lid using the cylinder 10 as well adds another layer of redundancy to the vent 1. [0032] When the piston is extended and working against the opening force of the gas struts, air pressure, such as in the order of 5 bar, may be applied to line 22, to hold the lid 3 closed. Additional air may then be supplied along line 23, at about 1 bar, to maintain a positive pressure inside the cylinder housing. This positive pressure provides a safety function that inhibits ingress of contaminants into the cylinder that might otherwise -6 interfere with proper operation of the cylinder 10. [0033] This is especially important in environments where there is regular dirt or fouling material, such as in a gaseous remediation system, as shown in Figure 3. [0034] Referring now to Figure 3, a gaseous (or volatile mixture or mixture ratio) abatement system 50 is shown as including a conduit 51 for feeding gaseous flow 52 typically (but not restricted to) from a mine (not shown), through the conduit 51 to a burner (exit or treatment system) 54. To prevent undesirable conditions at 54 and to have desirable control of substance mixture, various protection mechanisms are provided. One such mechanism is a fire curtain 55 that restricts the gas flow through the system 50. Another mechanism is a series of vents 1 in the roof 56 of the system 50 that allows the substance mixture to be dumped to atmosphere. [0035] Yet another mechanism is the use of one or more louvre assemblies 57, installed in a side wall 58 of the conduit 50, to modulate the air mix in the gas flow through the system 50 to thereby vary the methane/air mix delivered to the burner 54, as required. [0036] In the event of a catastrophic failure in the system 50, the various protection mechanisms are designed to fail in a manner to stop the flow of gas flow to the burner 54. The curtains 55 are designed to fail closed. The vents 1 are designed to fail open and the louver assemblies 57 are designed to fail open. It should be noted, however, that if required, the vents 1 and louvre assemblies 57 may instead be designed to fail closed instead, depending on operational requirements. [0037] To ensure appropriate fail safe operation, a vent operating system 60 is provided with a testing and control unit 61, a first air supply unit 62 for supplying high pressure air (in the order to 5 bar) and a second air supply unit 63 for supplying low pressure or default air (in the order of 1 bar). The low pressure air is used to supply air to the second line 23 and maintain a positive pressure in each cylinder 10 to keep the seals clear of debris.

-7 [0038] If a trigger or threshold event is registered that requires the vent to be opened, the control unit 61 can reduce the high pressure air delivered along line 22 or, alternatively, the control unit can divert high pressure air to the second line 23 in order to open the vent and/or allow the struts to open the vent. [0039] In the event of power failure and loss of high pressure air, the pressure applied by the cylinder 10 to keep the vent 1 closed will be removed, which will allow the struts 13 to open the vent automatically so that the vents failsafe open. [0040] By using a double acting cylinder, the invention provides a reliable failsafe measure that avoids the comparatively complicated locking device and release mechanism of the prior art. [0041] It should be noted various components of the vent 1, such as the frame 2, cylinder 10, arm 4 and struts 13 are preferably made of a metal construction (such as galvanized steel, aluminium, stainless steel or zincalum) and may be finished in Colorbond, anodized or powder coated finishes, or other typical roofing or walling material. Since the vent 1 is intended to operate in a gaseous and potentially volatile environment, it is important that any metal-on-metal contact or static charge build-up be avoided. For that purpose, all the various bushes associated with mounting the component parts to the frame 2 and the lid 3 are preferably formed of Teflon (or other anti-static material) insulators. The seal 16 likewise prevents any metal-on-metal contact between the components of the vent 1. As a result, the vent 1 is ideal for use in the gaseous abatement system 50 and is suitable for use in any other ventilation application where spark resistance is required. [0042] The invention has been described by way of non-limiting example only and many modification and variations may be made without departing from the spirit and scope of the invention described.

LIST OF PARTS 1. Vent 2. Frame 3. Lid 4. Hinges 5. Hinge plate 6. Hinge plate 7. Channel 8. End 9. Fulcrum arm 10. Cylinder 11. Cross beam 12. Pin 13. Struts 14. Upper mount 15. Periphery 16. Seal 17. Opening 18. Side section 19. Channel 20. 21. 22. First line 23. Second line 24. Centre frame 25. End plate 26. Rear clevis 27. Clevis pin 28. Spacers 29. Holes -9 30. Thrust bush 31. Circlip 32. Piston rod clevis 33. Tail end 34. Thrust bush 35. Thrust bush 36. Holes 37. Thrust bush 38. Circlip 39. Gas strut nipple 40. Nut 41. Nipple 42. Nut 43. Roller bearings 44. Roller pin 45. Bushes 46. Piston 47. 48. 49. 50. Abatement system 51. Conduit 52. Flow 53. 54. Burner 55. Fire curtain 56. Roof 57. Louvre assemblies 58. Side wall 59. 60. Vent operating system - 10 61. Testing unit 62. Air supply unit 63. Air supply unit

Claims (10)

1. A vent with a double acting cylinder for holding the vent in one of an open or a closed condition.

2. The vent of claim 1, further including a lid and a fulcrum arm for coupling the lid to a piston of the cylinder, with rollers mounted directly to the arm for rolling engagement in a channel of the lid.

3. The vent of claim 2, further including gas struts connected between a frame of the vent and the lid, either side of the guide, for forced opening of the lid.

4. The vent of claim 3, wherein a seal is provided between a piston and a housing of the cylinder, the seal with positive pressure internally of the cylinder, in order to resist ingress of debris into the cylinder.

5. A method of operating the vent of any one of claims 1 to 4, including applying air pressure to the cylinder to hold the vent in one of a closed or an opened condition.

6. The method of claim 5, further including applying positive air pressure simultaneously to both first and second air supply lines of the cylinder.

7. The method of claim 6, wherein the method includes applying air pressure in order to prevent ingress of debris into the cylinder.

8. The method of claim 7, wherein the method includes controlling air pressure applied to the supply lines to move the vent between a closed and opened condition. - 12

9. The method of claim 8, wherein the method includes allowing struts to force the vent into an open condition, as a failsafe measure, such as during an interruption in pressure supplied to the cylinder.

10. A vent operating system including a vent, as defined in any one of claims 1 to 4, a pressure supply for supplying pressure to the cylinder and a control unit to control operation of the vent in accordance with the method defined in any one of claims 5 to 9.