GB2391290A

GB2391290A - Gas relief valve

Info

Publication number: GB2391290A
Application number: GB0309698A
Authority: GB
Inventors: Anthony Cowan
Original assignee: G&K Valve Services Ltd
Current assignee: G&K Valve Services Ltd
Priority date: 2002-05-11
Filing date: 2003-04-29
Publication date: 2004-02-04
Also published as: GB0210803D0; GB0309698D0

Abstract

A gas relief valve comprises only a single chamber and float which allows for the escape of gas from a large orifice during emptying or filling of the fluid system, and from a smaller orifice during normal operation. The gas relief valve 10 has a float 30 located within a chamber 14, the float 30 being made up of two members 31, 32 slidably connected together. The first member 31 is adapted to slide between an upper and a lower position relative to the second member 32. The second 32 member includes a vent port 42 connected to an outlet 22 such that gas may pass between the two members 31, 32 and exit the chamber 14 via the vent port 42 when the first member 31 is in the lower position.

Description

2391 290

1 Gas Relief Valve 3 The present invention relates to valves. More 4 particularly, the invention relates to gas relief 5 valves.

7 It is known to utilize gas relief valves to allow 8 the escape of the gas that is present, or can 9 accumulate, in a system containing a fluid. The gas 10 may be air which becomes trapped in the system and 11 can then inhibit the flow of the fluid.

12 Alternatively, the gas may be produced within a 13 sewage system as the sewage decomposes. As a 14 further alternative, the gas may be present in a two 15 phase flow system where the extraction of the gas is 16 required. The fluid may be water, or another 17 liquid, or it may be sewage. The valves are 18 typically connected to the pipe-work of the system 19 at a relatively high position where the gas will 20 accumulate.

1 The gas relief valves may be actuated manually, or 2 they may be actuated by an internal float that opens 3 the outlet of the valve when the level of fluid in a 4 chamber of the valve decreases to a predetermined 5 level. In the latter case, it is typical to have 6 two chambers within the valve with a float 7 positioned in each chamber. A first float opens and 8 closes a first outlet that is relatively large in 9 diameter and is operated when the system is being 10 filled or emptied. On such occasions, the first 11 outlet will be open when the fluid is at a low level 12 in the system and so air locks or vacuums are 13 avoided. A second float opens and closes a second 14 outlet that has a lesser diameter during normal 15 operation of the system. The second float is 16 generally pivotally connected to a valve seating of 17 the second outlet. Known air relief valves that 18 incorporate two chambers and floats incur a greater 19 cost and complexity of manufacturing.

21 According to the present invention, there is 22 provided a gas relief valve comprising: 23 a housing defining a chamber, the chamber 24 having an outlet; and 25 a float located within the chamber and having 26 first and second members slidably connected by at 27 least one connecting member, wherein 28 the first member is adapted to slide between an 29 upper and a lower position relative to the second 30 member; and 31 the second member includes a vent port in 32 communication with the outlet such that gas may pass

( 3 1 between the first and second members and exit the 2 chamber via the vent port when the first member is 3 in the lower position.

5 Preferably the or each connecting member is 6 substantially vertical. Preferably the or each 7 connecting member includes an end stop to limit the 8 travel of the first member. Preferably the first 9 and second members are connected by three connecting lo members.

12 Preferably a seal is provided between the first and 13 second members. Preferably the seal is provided at 14 the vent port. Preferably the seal is connected to 15 the first member and extends by a predetermined 16 distance into the vent port such that the first 17 member is in the lower position when the first 18 member is at a distance from the second member 19 greater than the predetermined distance.

21 Alternatively a nozzle is provided at the vent port.

22 Preferably the nozzle extends from the second member 23 into a recess provided at the first member for a 24 predetermined distance such that the first member is 25 in the lower position when the first member is at a 26 distance from the second member greater than the 27 predetermined distance.

29 Preferably the first member comprises a head portion 30 integral with a buoyant portion. Alternatively the 31 first member comprises a head portion located at a 32 distance from a buoyant portion, the head portion

1 and the buoyant portion connected by a connecting 2 rod. One or more guide members may be interposed 3 between the head portion and the buoyant portion to 4 guide the float in a substantially vertical 5 direction. The or each guide member may include 6 filter means.

8 Preferably the float is initially positioned 9 proximal to the base of the chamber. Preferably the 10 second member is adapted to resiliently deform when 11 forced against the outlet as the level of fluid in 12 the chamber rises such that the second member 13 remains at the outlet when the level of fluid in the 14 chamber decreases.

16 Preferably the chamber includes an inlet provided 17 proximal to the base of the chamber and the air 18 relief valve includes connecting means such that the 19 valve may be connected to a portion of a fluid 20 system and the chamber inlet is in fluid 21 communication with the fluid system.

23 Embodiments of the present invention will now be 24 described, by way of example only, with reference to 25 the accompanying drawings, in which: 27 Fig. 1 is a sectional side view of a gas relief 28 valve along line I I of Fig. 2 according to a 29 first embodiment of the present invention; 31 Fig. 2 is a plan view of the gas relief valve of 32 Fig. 1; and

i ( 5 2 Fig. 3 is a sectional side view of a gas relief 3 valve according to a second embodiment of the 4 present invention.

6 Fig. 1 shows a first embodiment of a gas relief 7 valve 10 in accordance with the present invention.

8 The valve 10 may be provided in different sizes to 9 accommodate different pressure ratings, such as 6, 10 10, 16 or 25 bar.

12 The valve 10 has an outer housing 12 that defines an 13 inner chamber 14. The housing 12 is typically 14 manufactured from cast iron. An inlet 16 is 15 provided at the base of the chamber 14. A flange 18 16 is provided at the base of the housing 12. The 17 valve 10 is adapted to be connected to pipework of a 18 fluid system (not shown) in a conventional manner, 19 such as screwed connection, welding or bolting.

21 The top portion 20 of the housing 12 is an annular 22 plate bolted to the valve body. The top portion 20 23 has an aperture which defines an outlet 22 through 24 which the gas may escape from the chamber 14. The 25 top portion 20 is preferably constructed from cast 26 iron.

28 Within the chamber 14 there is provided a float 30 29 which comprises a first member 31 and a second 30 member 32. The first member 31 consists of a head 31 portion 34 integrally formed with a buoyant portion 32 36. The mass of the float 30 is adapted for correct

( 6 1 operation. The float 30 may include weights at the 2 base or the float may be partially filled with sand.

3 Typically a float 30 with a mass of 1.6 kg is used 4 for a valve having any pressure rating. The second 5 member 32 is preferably constructed from an 6 elastomer material.

8 Rubber O rings 24 are provided at the top portion 20 9 to seal the outlet 22 when the float 30 is 10 positioned at the outlet 22. A seal (not shown) may 11 be provided between the first and second members 31, 12 32.

14 The head portion 34 of the first member 31 includes 15 a number of connecting members, or pins 40, which 16 extend into a recess 35 provided at the second 17 member 32. Thus the first member 31 and the second 18 member 32 are slideably connected. The connecting 19 pins 40 include a pin head 41 and the recess 35 of 20 the second member 32 is stepped such that the pin 21 head 41 contacts the step of the recess 35 after 22 sufficient separation of the first member 31 from 23 the second member 32. The step of the recess 35 24 therefore provides an end stop to prevent the first 25 and second members 31, 32 from separating by more 26 than a predetermined distance. A typical maximum 27 distance is 3 mm.

29 The second member 32 also includes a vent port 42.

30 The diameter of the vent port 42 is dependent on the 31 pressure rating of the valve. Typically, the 32 diameter is 3 mm for a valve having a pressure

( 7 1 rating of 10 bar. The vent port includes a steel 2 insert (not shown) for increased stiffness and 3 strength. A seal 44 is provided on the head portion 4 34 and the seal 44 extends into the vent port 42.

6 Fig. 2 shows a plan view of the gas relief valve 10.

7 It can be seen that three connecting pins 40 are provided which are arranged equidistantly about the 9 centre of the valve 10 and from each other. The O 10 vent port 42 is provided at the centre of the valve 11 10.

13 It should be noted that the size of the chamber 14, 14 outlet 22 and, in particular, the vent port 42 may -

15 vary according to the pressure rating used for the = 16 fluid system.

17 3 18 In use, the float 30 is initially positioned at the 19 base of the chamber 14. As the fluid system is 20 filled, and fluid enters the chamber 14, the float 21 rises under the action of buoyancy. During this = 22 time, the outlet 22 would be open to atmosphere, or 23 connected another system for collecting the gas. -

24 This prevents the existence of any airlocks or the 25 creation of vacuums when the system is subsequently -

26 emptied. 28 When the level of fluid in the chamber 14 is 29 sufficiently high, the second member 32 of the float = 30 30 contacts the outlet 22 and the upwards force = 31 causes the second member 32 to deform and be -

( 1 retained at the outlet 22. The outlet 22 is 2 therefore sealed.

4 Gas accumulating in the system will tend to 5 accumulate at the highest point of the system which 6 will be the uppermost part of the chamber 14 of the 7 valve 10. Accumulating gas will cause the level of 8 fluid in the chamber 14 to decrease and the first 9 member 31 of the float 30 will move towards the base lo of the chamber 14 while the second member 32 remains 11 at the sealed outlet 22 under the pressure of the 12 gas.

13: 14 Separation of the first member 31 from the second 15 member 32 allows the gas to pass between the first 16 and second members 31, 32. When the distance is 17 sufficient, the seal 44 becomes free of the vent 18 port 42 and gas may pass into the vent port 42 and 19 escape from the chamber 14. The release of gas will 20 cause the level of fluid in the chamber 14 to again 21 rise and the first member 31 of the float will rise 22 towards the second member 32 and thus close off the 23 vent port 42.

25 The above operation will be repeated as gas 26 accumulates within, and then escapes from, the valve 27 10.

29 Fig.3 shows a second embodiment of the gas relief 30 valve 10. The valve 10 is similar in operation to 31 the valve of the first embodiment. However, the! 32 head portion 34 of the float 30 is separated from

( 9 1 the buoyant portion 36. The head portion 34 and the 2 buoyant portion 36 are connected by a connecting rod 3 50. 5 Two flange plates 52 are positioned between the head 6 portion 34 and the buoyant portion 36. The 7 connecting rod 50 is slideably mounted within a 8 guide member in the form of a central mounting block: 9 54 that is positioned within the upper flange plate 10 52. The mounting block 54 includes two apertures 56 2 11 to allow the flow of gas from the lower region 62 of 12 the chamber 14 to the upper region 62 of the chamber 13 14. Positioned above and below the mounting block: 14 54 are spider guides 58 to further guide the float I 15 30 within the chamber 14.: 17 The volume of the lower region 62 of the chamber 14 18 is calculated for the particular pressure rating of 19 the fluid system being used such that the fluid will 20 not reach a sufficient level so as to enter the 21 upper region 60 of the chamber 14. This embodiment I 22 of the present invention is therefore more suited to 23 applications where the fluid must not exit the 24 outlet 22, such as in applications involving sewage.

26 Fig. 3 shows the float 30 at an intermediate 27 position between the base and the top of the chamber 28 14. The float 30 may be in this position while the 29 fluid system (not shown) is being filled or emptied.

30 Once the second member 32 reaches the outlet 22, the 31 valve 10 will function as described for the first! 32 embodiment.

2 It can be appreciated that the present invention 3 comprises a gas relief valve 10 having only a single 4 chamber 14 and float 30. Nevertheless, the valve lo 5 allows for the escape of air from a large orifice 6 during emptying or filling of the fluid system, and 7 from a smaller orifice during normal operation.

9 Various modifications and improvements can be made 10 without departing from the scope of the present 11 invention. For example, a nozzle may be provided 12 between the first and second members 31, 32 at the 13 vent port instead of the seal. The nozzle extends 14 from the second member 32 into a recess provided at 15 the first member 31 for a predetermined distance 16 such that the first member 31 is in the lower 17 position when the first member 31 is at a distance 18 from the second member 32 greater than the lo predetermined distance.

Claims

1 Claims

3 1. A gas relief valve comprising 4 a housing defining a chamber, said chamber 5 having an outlet; and 6 a float located within said chamber and having 7 first and second members slidably connected to one 8 another by at least one connecting member, wherein 9 said first member is adapted to slide between 10 an upper and a lower position relative to said 11 second member; and 12 said second member includes a vent port in 13 communication with said outlet, wherein said float 14 is adapted such that the vent port moves between 15 closed and open states when the first member moves 16 between the upper and lower positions.

18

2. The gas relief valve as claimed in Claim 1 or 19 2, wherein the, or each, connecting member includes 20 an end stop to limit the travel of the first member.

22

3. The gas relief valve as claimed in any 23 preceding claim, wherein the first and second; 24 members are connected by three connecting members.

26

4. The gas relief valve as claimed in any 27 preceding claim, wherein a seal is provided between 28 the first and second members.

30

5. The gas relief valve as claimed in Claim 4, 31 wherein the seal is provided at the vent port.

1

6. The gas relief valve as claimed in Claim 5, 2 wherein the seal is connected to the first member 3 and extends by a predetermined distance into the 4 vent port such that the vent port remains in the 5 closed state until the first member is at a greater 6 distance from the second member than the 7 predetermined distance.

9

7. The gas relief valve as claimed in any of 10 Claims 1 to 3, wherein a nozzle is provided between 11 the first and second members.

13

8. A gas relief valve as claimed in Claim 7, 14 wherein the nozzle is provided at the vent port. I 16

9. A gas relief valve as claimed in Claim 7 or 8, 17 wherein the nozzle extends from the second member 18 into a recess provided in the first member for a 19 predetermined distance such that the vent port 20 remains in the closed state until the first member 21 is at a greater distance from the second member than I 22 the predetermined distance.

24

10. A gas relief valve as claimed in any preceding 25 claim, wherein the first member comprises a head 26 portion integral with a buoyant portion.

28

11. A gas relief valve as claimed in any of Claims 29 1 to 9, wherein the first member comprises a head 30 portion located at a distance from a buoyant 31 portion, the head portion and the buoyant portion 32 connected by a connecting rod.

( 2

12. A gas relief valve as claimed in Claim 11, 3 wherein one or more guide members are provided in 4 the chamber in order to guide the connecting rod in 5 a substantially vertical direction.

7

13. A gas relief valve as claimed in any preceding 8 claim, wherein the second member is adapted to 9 resiliently deform when forced against the outlet.

11

14. A gas relief valve as claimed in any preceding 12 claim, wherein the chamber includes an inlet 13 provided proximal to the base of the chamber.

15

15. A gas relief valve as claimed in Claim 14, 16 wherein the gas relief valve includes connecting 17 means such that the valve may be connected to a 18 portion of a fluid system and the chamber inlet is 19 in fluidic communication with the fluid system.

21

16. A gas relief valve as herein described with 22 reference to the accompanying drawings.