GB2231391A

GB2231391A - A one way air admittance valve

Info

Publication number: GB2231391A
Application number: GB9007884A
Authority: GB
Inventors: Patrick Daniel Frawley
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-04-07
Filing date: 1990-04-06
Publication date: 1990-11-14
Anticipated expiration: 2010-04-06
Also published as: GB2231391B; GB9007884D0

Abstract

A one way air admittance valve for admitting air into a pipe (3), e.g. a soil or waste pipe, comprises a body portion (4) for fitting to the pipe (3), at least one air inlet port (6) in the body portion (4), and closure means (8) which is longitudinally movable between a first position in which it seals the air inlet port (6) and a second position in which the air inlet port (6) is open for the admittance of air into the pipe (3), the same closure means (8) acting to close all of the air inlet ports (6), and the closure means (8) being such that it seals at two separate areas (10, 12) which are longitudinally spaced apart. The valve may open automatically on negative pressure in the pipe. The closure means (8) has a guide rod (30) or may cooperate with a guide rod on the body (4). Seals (18, 20) may be provided at the areas (10, 12), on either the body (4) or the closure means (8). <IMAGE>

Description

A ONE WAY AIR ADMITTANCE VALVE This invention relates to a one way air admittance valve and, more especially, this invention relates to a one way air admittance valve for admitting air into a pipe.

One way air admittance valves for admitting air into pipes are known. It is an aim of the present invention to provide a one way air admittance valve which is of a different construction to the known valves.

Accordingly, this invention provides a one way air admittance valve for admitting air into a pipe, which valve comprises a bod-portion for fitting to the pipe, at least one air inlet port in the body portion, and sealing means which is longitudinally movable between a first position in which it seals the air inlet port and a second position in which the air inlet port is open for the admittance of air into the pipe, the valve being such that there is only one sealing means for all of the air inlet ports, and the sealing means being such that it seals at two separate areas which are longitudinally spaced apart.

The valve of the present invention may be used on a soil pipe for a water closet, or a waste pipe for a sink or a bath. As the waste material passes along the soil pipe or the water passes along the waste pipe, a vacuum tends to be created which could suck the water from the pipetrap at the bottom of the toilet bowl of the water closet or at the underneath of the sink or the bath. With the valve of the present invention, air is appropriately admitted to stop the sealing water from being sucked out of the water trap, thereby to avoid odours creeping back up the soil pipe or the waste pipe. With a soil pipe, the valve can be used to cap the soil pipe in a bathroom or a loft, and the valve avoids the need to continue the soil pipe upwardly above the roof of the house, flat, office or other structure.

The valve may be one in which there are four of the inlet ports. Any appropriate and desired number of the inlet ports may be employed0 The inlet ports may be formed between web parts of the body portion.

The sealing means preferably comprises a sealing piston.

The sealing piston may engage with a pair of seals which are mounted in the body portion and which are longitudinally spaced apart, whereby the sealing piston effects a seal at the two separate areas.

In one embodiment of the invention, the valve is one in which the sealing piston has a top lip and a bottom wall, and in which the top lip and the bottom wall engage the pair of seals. The pair of seals may each be a lip seal which fits in a groove in the body portion and which projects from the groove inwardly into the body portion.

In another embodiment of the invention, the valve is one in which the sealing piston is frustoconical so that it has a sloping side wall, and in which the pair of seals engage over two spaced apart portions of the sloping side wall. The pair of seals may each be a lip seal which fits over a flange and which projects from the flange for engagement with the sloping side wall.

In either of the above mentioned two embodiments of the invention, the seals are stationary and the sealing piston moves. In alternative constructions, a seal or seals could be mounted on the sealing piston. Thus, for example, the valve may be one in which the sealing piston supports a single seal having an outwardly extending top flange and an inwardly extending bottom flange.

The sealing means may include a guide member for guiding the longitudinal movement of the sealing piston.

The guide member may be a guide rod which extends from the sealing piston and which runs in an aperture formed in a transverse part of the body portion. Alternatively, the guide member may be a guide rod which extends from the body portion and which extends into a guide bore in the sealing piston.

The body portion may have an open top which is closed by a lid. In this case, the lid may be provided with a- guide rod for locating in the bore in the piston, the guide rod forming the guide member.

Preferably, the lid is a screw lid which screws to the body portion. Usually, the screw lid will screw over the outside of the body portion but the screw lid may screw to the inside of the body portion if desired.

Preferably, the lid has sloping sides.

The lid may have first and second frusto-conical portions arranged one on top of the other.

The lid and the body portion may define therebetween an annular air inlet passage leading to the or each air inlet port.

The body portion and the lid may be made of a plastics material. The plastics material enables the body portion and the lid easily to be moulded. The sealing means may similarly be made from a plastics material. The actual seals are preferably made from a rubber material. The rubber material may be that used in known valves.

The valve will usually be such that the body portion fits over the pipe. If desired however the body portion may fit inside the pipe. The body portion will usually fit to the pipe with a push fit.

The valve may include cover means for covering at least a part of the valve. Thus the cover means may cover a top part of the valve.

The cover means may be made from a foamed plastics material. The foamed plastics material may be polystyrene. The foamed plastics material or other material from which the cover means is made may give thermal insulation to the valve and thus stop the sealing means from icing up in freezing conditions due to condensation being present in the valve.

The valve may be made in any desired sizes for fitting to various sized pipes. Thus, for example, the body portion may be made to fit to pipes which are 1.25, 1.5, 2, 3 or 4 inches in diameter. These pipe diameter sizes correspond to 38mm, 43mm, 50-55mm, 70-82mm and llOmm pipe diameter sizes. The pipe diameter sizes of 38mm and 43mm may be produced in ranges which extend to either side of these stated values.

Embodiments of the invention will now be described solely by way of example and with reference to the accompanying drawings in which: Figure 1 is a longitudinal section through a first one way air admittance valve; Figure 2 is a perspective view showing a piston employed in the valve shown in Figure 1; and Figure 3 is a longitudinal section through a second one way air admittance valve; Figure 4 is a longitudinal section through a third one-bay air admittance valve; and Figure 5 is a longitudinal section through a fourth one way air admittance valve.

Referring to Figures 1 and 2, there is shown a one way air admittance valve 2 for admitting air into a pipe 3. The valve 2 comprises a body portion 4 for fitting to the pipe 3 as shown. The valve 2 also comprises a number of air inlet ports 6 in the body portion 4. There may be one, two, three, four or more of the inlet ports 6 as may be desired.

The valve 2 further comprises sealing means 8 which is longitudinally movable between a first position which is shown in Figure 1 and in which the sealing means 8 seals the inlet ports 6, and a second position in which the inlet ports 6 are open for the admittance of air into the pipe. The valve 2 is such that only one sealing means 8 is employed for sealing all of the inlet ports 6. The sealing means 8 is such that it seals at two separate areas 10,12. These two separate areas 10,12 are longitudinally spaced apart.

The inlet ports 6 are formed between web parts 14 of the body portion 4.

The sealing means 8 comprises a sealing piston 16. The piston 16 engages with a pair of seals 18,20 which are mounted in the body portion 4 and which are longitudinally spaced apart, whereby the piston 16 effects a seal at the two separate areas 10,12. More specifically, the piston 16 has a top lip 22 and a bottom wall 24. The top lip 22 and the bottom wall 24 engage the seals 18,20 respectively.

The seals 18,20 are circular lip seals as shown and they each fit in a groove 26 in the body portion. The seals 18,20 each project from their groove 26 inwardly into the body portion 4 as shown in Figure 1.

The piston 16 has a side wall 28 which tapers slightly as shown. The bottom wall 24 of the piston 16 has a guide member in the form of a guide rod 30. The guide rod 30 extends into an aperture 32 formed in a transverse part 54 of the body portion 4. The transverse part 34 may be formed by a spoke arrangement similar to the spoke arrangement 36 which forms part of the bottom wall 24 of the piston 8.

The body portion 4 has an open top 38 which is closed by a lid 40. The lid 40 is a screw lid which screws to the top 38 of the body portion 4. More specifically, the lid 40 screws over the outside of the top 38 by virtue of the illustrated mating screw threads 42. As the lid 40 is screwed down, it engages a seal 44 to effect a good seal at this point. The seal 44 may be a ring seal located in a groove 46 in the lid 40.

The lid 40 has sloping sides. More specifically, the lid 40 has a first frustoconical portion 48 and a second frustoconical portion 50. The first and the second frustoconical portions 48,50 are arranged one on top of the other as shown in Figure 1.

The lid 40 and the body portion 4 define therebetween an annular air inlet passage 52 leading to the inlet ports 6. The passage of air is shown by the arrows 54.

The body portion 4, the piston 16 and the lid 40 may be moulded from plastics material. The seals 18,20 are made from plastics materials of the type usually used in one way air admittance valves for admitting air into pipes.

The valve 2 shown in Figures 1 and 2 operates such that when flushing of a water closet has not occurred, there will be a positive pressure in the pipe 3. The piston 16 will then be in its sealing position as shown in the left hand half of Figure 1.

When the water closet is flushed, a negative pressure or vacuum will occur in the pipe 3 and this might drag water from the sealing trap beneath the toilet bowl in the water closet. This is prevented by air entering the pipe 3 as shown by the arrows 54. Thus the air passes through the inlet passage 52, through the inlet ports 6 and through apertures 56 formed in the transverse part 34 of the body portion 4. When the flushing ceases, the negative pressure ceases and the piston 6 then returns to its sealing position to stop the escape of unpleasant odours that might otherwise pass up the pipe 3 and escape via the valve 2.

Referring now to Figure 3, there is shown a second valve 2. Similar parts as in Figures 1 and 2 have been given the same reference numerals for ease of comparison and understanding, and their precise construction and operation will not again be given.

In Figure 3, it will be seen that the piston 16 is slightly different and also that the seals 18,20 are slightly different. More specifically, the seals 18,20 are lip seals. Each lip seal 18,20 fits over a flange 58 and the seal 18,20 projects from the flange 58 as shown for engagement with the sloping side wall 28 of the piston 16. It will be seen that the sloping side wall 28 in Figure 3 tapers more acutely than in Figure 1.

In Figure 3, the guide rod 30 extends from the lid 40 and into a guide bore 60 in the piston 16.

Referring now to Figure 4, there is shown a third valve 2. Similar parts as in Figures 1 and 2 have been given the same reference numerals for ease of comparison and understanding. In Figure 4, there is shown a single seal 62. This seal 62 has a bottom flange 64 and a top flange 66. The seal 62 fits over the piston 16. The piston 16 is provided with a shoulder 68 against which the seal 62 abuts. As can be seen from Figure 4, the seal 62 is in the form of a cylinder.

The piston 16 slides up and down on a guide rod 30 which extends upwardly as shown and which is connected to the body portion 4 by a connecting part 70.

The lid 40 shown in Figure 4 is different from the lid 40 shown in Figures 1 to 3, but, generally, any shape of lid may be employed.

The construction shown in Figure 4 is easy to assemble. The seal 62 also operates well and, in this connection, it will be noted that the bottom flange 64 and the top flange 66 are made of relatively thin material which is free to move up and down. This is because the bottom flange 64 is spaced from the adjacent part of the piston 16 by a bead 72. Similarly, the top flange 66 is spaced apart from the top part of the piston 66 by virtue of the shoulder 68.

Referring now to Figure 5, there is shown a fourth valve 2 which is like the third valve 2 shown in Figure 4 and in which similar parts have been given the same reference numerals. In Figure 5 it will be seen that the body portion 4 and the lid 40 are shaped differently than in Figure 4.

Also the seal 46 is located at a different position.

Further, three guide rods 30 are employed, the guide rods 30 being mounted on the body portion 4.

It is to be appreciated that the embodiments of the invention described above with reference to the accompanying drawings have been given by way of example only and that modifications may be effected. Thus, for example, the valves 2 may be made in any desired sizes for fitting to appropriately sized pipes. The pipe 3 need not be a soil pipe and it may be for example, a waste pipe from a sink, bathroom or other area. Generally, the valves 2 may be fitted to any pipe in which it is required to allow the one way admittance of air.

If desired, the valves 2 may be provided with cover means (not shown). The cover means may cover a top part of the valves 2 and the cover means may be made from a fbamed plastics material such for example as polystyrene.

The cover means may give thermal insulation/protection in order to help to stop the pistons 16 freezing up in freezing conditions due to condensation forming in the valve 2 and then freezing.

Claims

1. A one way air admittance valve for admitting air into a pipe, which valve comprises a body portion for fitting to the pipe, at least one air inlet port in the body portion, and sealing means which is longitudinally movable between a first position in which it seals the air inlet port and a second position in which the air inlet port is open for the admittance of air into the pipe, the valve being such that there is only one sealing means for all of the air inlet ports, and the sealing means being such that it seals at two separate areas which are longitudinally spaced apart.

2. A one way air admittance valve according to claim 1 in which there are four of the inlet ports.

3. A one way air admittance valve according to claim 2 in which the air inlet ports are formed between web parts of the body portion.

4. A one way air admittance valve according to any one of the preceding claims in which the sealing means comprises a sealing piston.

5. A one way air admittance valve according to claim 4 in which the sealing piston engages with a pair of seals which are mounted in the body portion and which are longitudinally spaced apart, whereby the sealing piston effects a seal at the two separate areas.

6. A one way air admittance valve according to claim 5 in which the sealing piston has a top lip and a bottom wall, and in which the top lip and the bottom wall engage the pair of seals.

7. A one way air admittance valve according to claim 6 in which the pair of seals are each a lip seal which fits in a groove in the body portion and which projects from the groove inwardly into the body portion.

8. A one way air admittance valve according to any one of claims 1 to 5 in which the sealing piston is frusto-conical so that it has a sloping side wall, and in which the pair of seals engage over two spaced apart portions of the sloping side wall.

9. A one way air admittance valve according to claim 8 in which the pair of seals are each a lip seal which fits over a flange and which projects from the flange for engagement with the sloping side wall.

10. A one way air admittance valve according to any one of claims I - 4 in which the sealing piston supports a single seal having an outwardly extending top flange and an inwardly extending bottom flange.

II. A one way air admittance valve according to claim 4 or to claim 4 and any claim when appendent to claim 4 in which the sealing means includes a guide member for guiding the longitudinal movement of the sealing piston.

12. A one way air admittance valve according to claim 71 in which the guide member is a guide rod which extends from the sealing piston and which runs in an aperture formed in a transverse part of the body portion.

13. A one way air admittance valve according to claim 11 in which the side member is a guide rod which extends from.

the body portion and which extends into a guide bore in the sealing piston.

14. A one way air admittance valve according to any one of the preceding claims in which the body portion has an open top which is closed by a lid.

15. A one way air admittance valve according to any one of claims 1 - II and 14 in which the lid is provided with a guide rod for locating in the bore in the piston, the guide rod forming the guide member.

16. A one way air admittance valve according to claim 14 or 15 in which the lid is a screw lid which screws to the body portion.

17. A one way air admittance valve according to any one of claims 14 - 16 in which the lid has sloping sides.

18. A one way air admittance valve according to any one of claims 14 - 17 in which the lid has first and second frustoconical portions arranged one on top of the other.

19. A one way air admittance valve according to any one of claims 14 - 18 in which the lid and the body portion define therebetween an annular inlet passage leading to the or each air inlet port.

20. A one way air admittance valve according to any one of the preceding claims and including cover means for covering at least a part of the valve.

21. A one way air admittance valve according to claim 20 in which the cover means covers a top part of the valve.

22. A one way air admittance valve according to claim 20 or claim 21 in which the cover means is made of a foamed plastics material.

23. A one way air admittance valve substantially as herein described with reference to the accompanying drawings.