GB1571449A

GB1571449A - Vent/relief valve for a sewage system

Info

Publication number: GB1571449A
Application number: GB3438277A
Authority: GB
Original assignee: Adams Hydraulics Ltd
Current assignee: Adams Hydraulics Ltd
Priority date: 1978-05-16
Filing date: 1978-05-16
Publication date: 1980-07-16

Description

(54) VENT/RELIEF VALVE FOR A SEWAGE SYSTEM (71) We. ADAMS-HYDRAULICS LI MITED, a British Company of Peaseholme Green, York, Yorkshire, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a combined vent and relief valve for use with conduits along which a liquid is pumped, and specifically, but not exclusively, to such a valve for use in ventilating and relieving pressure in a sewer main.

In sewer mains along which sewage is pumped periodically it is desirable to allow large volumes of air to flow into and out of the main during filling and emtpying of the main and to permit the escape of small quantities of gas which can accumulate in the main during pumping. When the main is pressurized, during pumping, the ventilation means must be closed to prevent sewage being pumped therethrough but at the same time it is necessary to allow any accumulation of gas pressure in the main to be relieved.

In a rising main along which liquid is pumped. when the pump is stopped the liquid in the main initially continues to flow along the main due to momentum and a vacuum is created between the pump and the liquid. The column of liquid after losing momentum then reverses direction and due to the vacuum flows back towards the pump and the column of liquid tends to oscillate in the conduit, which is undesirable.

The present invention aims to provide a combined vent and air relief valve which will allow large volumes of air to flow into a conduit when a conduit is being emptied to prevent the formation of a vacuum and will also relieve gas pressure in the conduit.

According to the present invention there is provided a combined vent and relief valve for use in ventilating and relieving pressure in a conduit along which a liquid is pumped, comprising a casing defining a chamber having an inlet which can be connected to a said conduit and an outlet connecting the chamber to the atmosphere, a float located within the chamber, a rod connected to the float for movement therewith, a valve closure member axially movable mounted on the end portion ot said rod remote from the float for opening and closing said outlet, said valve closure member having an axial passage therein which extends through the valve closure member and which can be closed by a portion of the rod.

In one use of the valve according to the present invention the valve closure member is moved by said float and rod into a position in which it closes said outlet when liquid enters the chamber from said conduit, any gas then collecting in the chamber being vented to atmosphere through the axial passage in the valve closure member and through said outlet by said rod being moved by the float relative to said valve closure member to open said passage.

Preferably the outlet is provided with a valve seat formed of rubber and the valve closure member is formed of metal, such as stainless steel.

The axial passage in the valve closure member preferably comprises a stepped bore, the larger diameter portion receiving a reduced diameter portion of the rod which is of less diameter than that of the larger diameter portion of the bore.

Preferably the rod is axially guided in the casing by extending through a bush carried by the casing.

Two embodiments of the present invention will now be described, by way of examples. with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section through one embodiment of a combined vent and relief valve according to the present invention, and Figure 2 is a longitudinal section through the upper part of a combined vent and relief valve according to the present invention for use in a rising main.

The valve shown in Figure 1 comprises a casing 10 preferably formed of metal, such as iron, which defines a float chamber 11.

At the bottom of the casing 10 is an inlet 12 having a flange 13 to enable the casing 10 to be connected to a rising main via an isolating valve (now shown). The float chamber 11 has a hemi-spherical base portion to prevent the retention of solid matter within the float chamber 11 when the chamber is emptied. Disposed in the float chamber 11 is a float 14 which is connected to the lower end of a rod 15 which is slidably received in a bush 16 mounted in a cover 17 provided with air passages 17' and which is fastened to an upper flange 18 on the casing 10. A sealing member 19 is interposed between the flange 18 and the cover 17.

Mounted on the cover 17 is a cylindrical member 20 which at its upper end is provided with a flange 21 to which is fastened a plate 22 provided with an outlet orifice 23. Surround the outlet orifice 23 is a valve seat 24 formed of rubber or similar resilient material. such as a plastics mate rial. Secured to the flange 21 by means of bolts 25 and spacer members 26 is a cover plate 27 to prevent rain and debris entering the outlet orifice 23 but beneath which air can flow to and from the orifice 23.

The upper end of the rod 15 is provided with a reduced diameter portion 28 which extends upwardly from a frusto-conical por tion 29. Slideably mounted on the upper end portion 28 is a valve closure member 30 formed of metal. such as stainless steel. The valve closure member 30 has a part spherical head portion 31 and is provided with an axial passage in the form of a stepped bore 32 the axial bore portion 33 having a diameter larger than that of the rod portion 28. Secured to the lower end of the valve closure member 30 is an annular sealing member 34 formed of rubber or similar material, such as plastics material, which when the valve closure member 30 is in the position shown in the drawing seals against the frusto-conical portion 29 to close the end of the axial bore portion 33 of the bore 32.

Provided on the cover 17 are lifting eyes 35 and the casing 10 is provided with an opening closed by a plug 36. When the plug 36 is removed access can be had to the float chamber 11 through the opening.

The rod 15 is provided with a flange 37 which can co-operate with the upper end of the bush 16 to form a stop to limit the downward movement of the rod 15 to ensure that in its lowermost position the float 14 does not obstruct the inlet 12.

The valve can be connected to a conduit to act as a vent/pressure relief valve and operates as follows. When there is no flow in the conduit the float 14 will be in its lowest position with the flange 37 resting on the bush 16. In this position the orifice 23 is open allowing atmospheric air to flow through the valve to the conduit and to allow any gases in the main to flow through the valve to atmosphere. In this position the annular sealing member 34 of the valve closure member 30 seals against the frustoconical portion 29.

When liquid, such as sewage effluent, is pumped through the conduit air/gas is initially allowed to exhaust freely through the valve and out of the orifice 23. When all air/gas has been expelled, liquid will enter the float chamber 11 through the inlet 12 and the float 14 and rod 15 will rise bringing the valve closure member 30 into sealing engagement with the valve seat 24 thus closing off the orifice 23. The sealing member 34 will still contact the frusto-conical portion 29. The exhaust of air/gas now ceases and the flow of liquid into the float chamber 11 is virtually stopped. The remaining air/gas in the valve is compressed until the maximum working pressure in the conduit is reached.

When the pressure in the conduit reduces, such as when pumping is stopped, the liquid will leave the float chamber 11 through the inlet 12 and the float 14 and rod 15 move down to move the valve closure member 30 away from the valve seat 24 thus opening the orifice 23 to allow air to re-enter the conduit and to allow any gases in the conduit above atmospheric pressure to escape.

Under certain conditions when the orifice 23 is closed by the valve closure member 30 any gas/air entrained in the liquid in the conduit can collect in the valve above the liquid level therein. This gas/air can buildup in pressure and acts on the float 14 causing it to move downwards a distance sufficient to move the frusto-conical portion 29 out of sealing engagement with the sealing member 34 to open the orifice formed by the passage 32 and bore 33. The gas/air pressure maintains the valve closure member 30 in sealing contact with the valve seat 24. The gas/air then flows out of the valve through the passage 32, bore 33 and orifice 23 whilst the orifice 23 remains closed by the valve closure member 30 which is held against the valve seat 24 by gas/air pressure in the valve . As the gas/air escapes the level of liquid will rise causing the float 14 to rise and bring the frustoconical portion 29 back into sealing engagement with the sealing member 34.

The valve is suitable for use with pumping mains where frequent filling and emptying of the main occurs and where it is important to prevent syphoning taking place.

Figure 2 shows a valve which is similar to that of Figure 1 and which can be connected to a rising main along which liquid is pumped. The parts of the valve not shown in Figure 2 are identical to those shown in Figure 1. The orifice plate 22 of the valve of Figure 2 is provided with a cylindrical portion 38 closed by an end wall 39 to form a chamber 40. The cylindrical portion 38 is provided with large apertures 41 and the end wall 39 is provided with an aperture 42 containing a bush 43 whose bore 44 is suitablv calibrated. Movable in the chamber 40 is a light-weight piston 45 having a plurality of apertures 46 and a small central aperture 47 in its end wall, the hole 47 being aligned with the bore 44 of bush 43.When the pump is stopped the liquid will be withdrawn from the chamber 11 and consequently the float 14 will be lowered and the valve member 30 will be moved awav from the valve seat 24. The piston 45 will move downwardly to allow a large volume of air to flow into the valve through the apertures 41.

46 and 47 and thus into the conduit to prevent the formation of a vacuum in the conduits between the pump and the liquid.

When the column of liquid reverses direction after losing its momentum it will compress the air and force the piston 45 up to the top of the cvlinder 38. The apertures 46 will be closed bv the end wall 39 and the apertures 41 will be closed by the skirt portion of the piston 45. The aperture 47 is placed in communication with the bore 44 of bush 43 and the air will escape only slowly from the valve unit through the bore 44 and this allows the air in the svstem to dampen the oscillations of the column of liquid in the rising main. In this use of the valee unit.

large volumes of air are admitted to the conduit when pumping is stopped. to prevent a vacuum being maintained in the conduit. and this air is discharged gradually when pressurized by the return flow of liquid.

The valve is specificallv intended for use with sewage mains but it can be used for any installation where a liquid has to be pumped along a conduit. such as water mains or liquid chemical conveying conduits.

WHAT WE CLAIM IS:- I. A combined vent and relief valve for use in ventilating and relieving pressure in a conduit along which a liquid is pumped, comprising a casing defining a chamber having an inlet which can be connected to a said conduit and an outlet connecting the chamber to the atmosphere. a float located within the chamber. a rod connected to the float for movement therewith. a valve closure member axially movably mounted on the end of said rod remote from the float for opening and closing said outlet, said valve closure member having an axial passage therein which extends through the valve closure member and which can be closed by a porton of the rod.

2. A valve as claimed in claim 1, in which the outlet is provided with a resilient valve seat and the valve closure member is formed of metal.

3. A valve as claimed in claim 2, in which the valve seat is formed of rubber.

4. A valve as claimed in any preceding claim, in which the portion of the rod which can close the axial passage comprises a frusto-conical portion of the rod.

5. A valve as claimed in any preceding claim, in which the axial passage in the valve closure member comprises a stepped bore, the larger diameter portion receiving a reduced diameter portion of the rod which is of less diameter than that of the larger diameter portion of the bore.

6. A valve as claimed in claim 5, in which the open end of the larger diameter portion of the stepped bore is provided with a resilient sealing member against which said portion of the rod can be brought into sealing engagement.

7. A valve as claimed in claim 6, in which the sealing member comprises an annular resilient member secured to the end of the valve closure member.

8. A valve as claimed in any preceding claim, in which the rod extends through a guide bush carried by the casing.

9. A valve as claimed in any preceding claim. in which the portion of the valve closure member which controls the outlet is part-spherical.

10. A valve as claimed in any preceding claim, in which stop means are provided to prevent the float obstructing the inlet when the float is in its lowermost position.

11. A valve as claimed in any preceding claim, in which the inlet is located at the bottom of the chamber and the bottom wall of the chamber is hemi-spherical.

12. A valve as claimed in any preceding claim, in which the outlet communicates with a chamber formed above the outlet, said chamber being formed by an annular wall portion and an end wall, said wall portion being provided with apertures and said end wall being provided with a central aperture a piston axially movable in said chamber, said piston having an end wall provided with apertures and a central aperture aligned with said central aperture in the end wall, said piston when in its lowermost position enabling air to flow into the valve through the apertures in the annular wall portion and through the apertures in the piston and said piston when in its uppermost

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

The valve is suitable for use with pumping mains where frequent filling and emptying of the main occurs and where it is important to prevent syphoning taking place.

Figure 2 shows a valve which is similar to that of Figure 1 and which can be connected to a rising main along which liquid is pumped. The parts of the valve not shown in Figure 2 are identical to those shown in Figure 1. The orifice plate 22 of the valve of Figure 2 is provided with a cylindrical portion 38 closed by an end wall 39 to form a chamber 40. The cylindrical portion 38 is provided with large apertures 41 and the end wall 39 is provided with an aperture 42 containing a bush 43 whose bore 44 is suitablv calibrated. Movable in the chamber 40 is a light-weight piston 45 having a plurality of apertures 46 and a small central aperture 47 in its end wall, the hole 47 being aligned with the bore 44 of bush 43.When the pump is stopped the liquid will be withdrawn from the chamber 11 and consequently the float 14 will be lowered and the valve member 30 will be moved awav from the valve seat 24. The piston 45 will move downwardly to allow a large volume of air to flow into the valve through the apertures 41.

46 and 47 and thus into the conduit to prevent the formation of a vacuum in the conduits between the pump and the liquid.

When the column of liquid reverses direction after losing its momentum it will compress the air and force the piston 45 up to the top of the cvlinder 38. The apertures 46 will be closed bv the end wall 39 and the apertures 41 will be closed by the skirt portion of the piston 45. The aperture 47 is placed in communication with the bore 44 of bush 43 and the air will escape only slowly from the valve unit through the bore 44 and this allows the air in the svstem to dampen the oscillations of the column of liquid in the rising main. In this use of the valee unit.

large volumes of air are admitted to the conduit when pumping is stopped. to prevent a vacuum being maintained in the conduit. and this air is discharged gradually when pressurized by the return flow of liquid.

The valve is specificallv intended for use with sewage mains but it can be used for any installation where a liquid has to be pumped along a conduit. such as water mains or liquid chemical conveying conduits.

WHAT WE CLAIM IS:- I. A combined vent and relief valve for use in ventilating and relieving pressure in a conduit along which a liquid is pumped, comprising a casing defining a chamber having an inlet which can be connected to a said conduit and an outlet connecting the chamber to the atmosphere. a float located within the chamber. a rod connected to the float for movement therewith. a valve closure member axially movably mounted on the end of said rod remote from the float for opening and closing said outlet, said valve closure member having an axial passage therein which extends through the valve closure member and which can be closed by a porton of the rod.
2. A valve as claimed in claim 1, in which the outlet is provided with a resilient valve seat and the valve closure member is formed of metal.
3. A valve as claimed in claim 2, in which the valve seat is formed of rubber.
4. A valve as claimed in any preceding claim, in which the portion of the rod which can close the axial passage comprises a frusto-conical portion of the rod.
5. A valve as claimed in any preceding claim, in which the axial passage in the valve closure member comprises a stepped bore, the larger diameter portion receiving a reduced diameter portion of the rod which is of less diameter than that of the larger diameter portion of the bore.
6. A valve as claimed in claim 5, in which the open end of the larger diameter portion of the stepped bore is provided with a resilient sealing member against which said portion of the rod can be brought into sealing engagement.
7. A valve as claimed in claim 6, in which the sealing member comprises an annular resilient member secured to the end of the valve closure member.
8. A valve as claimed in any preceding claim, in which the rod extends through a guide bush carried by the casing.
9. A valve as claimed in any preceding claim. in which the portion of the valve closure member which controls the outlet is part-spherical.
10. A valve as claimed in any preceding claim, in which stop means are provided to prevent the float obstructing the inlet when the float is in its lowermost position.
11. A valve as claimed in any preceding claim, in which the inlet is located at the bottom of the chamber and the bottom wall of the chamber is hemi-spherical.
12. A valve as claimed in any preceding claim, in which the outlet communicates with a chamber formed above the outlet, said chamber being formed by an annular wall portion and an end wall, said wall portion being provided with apertures and said end wall being provided with a central aperture a piston axially movable in said chamber, said piston having an end wall provided with apertures and a central aperture aligned with said central aperture in the end wall, said piston when in its lowermost position enabling air to flow into the valve through the apertures in the annular wall portion and through the apertures in the piston and said piston when in its uppermost

position allowing air to flow out of the valve only through the aligned central apertures.
13. A valve as claimed in claim 12, in which the central aperture in the end wall is formed in a bush.
14. A combined vent and relief valve for use in ventilating and relieving pressure in a conduit along which a liquid is pumped, substantially as herein before described with reference to and as illustrated in Figure 1 or Figure 2 of the accompanying drawings.
15. A valve as claimed in any preceding claim connected to a conduit along which liquid can be pumped.
16. A valve as claimed in claim 15, in whch the conduit comprises a rising main.