GB2233737A

GB2233737A - Non-return valve

Info

Publication number: GB2233737A
Application number: GB8916249A
Authority: GB
Inventors: Albert Fletcher Wigley
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-07-15
Filing date: 1989-07-15
Publication date: 1991-01-16
Also published as: GB8916249D0

Abstract

A non-return valve is composed of four parts, viz an inlet body 10 with a mounting flange 11 and an internal venturi surface; the body 10 interlocking through dimples at 39 with another part in the form of an outlet cage 34 which supports a third part in the form of a spring 30 biassing the final part, a valve member 20. The inlet body has external surfaces to eliminate turbulence. The valve member 20 is finned at 21 and has two valve faces, one solid and one provided by an elastomeric ring 24, to seat on respective faces 15, 16 of the inlet body. The valve may be included as one valve of an anti-siphonage valve arrangement. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO FLUID CONTROL VALVES This invention relates to a non-return valve sub-assembly when incorporated in a valve body and installed in a fluid flow line allows the fluid to flow in one direction only and in particular for the prevention of backflow and backsyphonage in drinking and domestic water supplies.

In view of the public attention that is now given to the maintenance of a potable and wholesome water supply from public water mains it is selfevident that rigid precautions and testing standards must be observed where contamination from harmful substances can take place, whether pumped into or discharged from connections to public water mains or where drinking water from any source of supply is drawn from a discharge outlet.

Water Byelaws now define that a double check valve is the minimum requirement that can be accepted at discharge points and in certain cases a double check valve is an insufficient safeguard.

It is in the public interest that devices dealing with backflow and backsyphonage in water supplies used for drinking and domestic consumption should not be described in the generic term of check valves which invariably deals with circulating systems and the maintenance of pressure and volume once the liquid has passed through the check valve and no damage or harm is caused if the fluid leaks back through the check valve providing the quality and material content remains the same.

A non-return valve should be as stated - leak-proof and fail-safe if possible.

According to the invention there is provided a non-return valve assembly comprised of four parts with the first part being a valve body with an external flange for incorporating in a valve body or casing having pipe connectors, the flanged body having an upper external part for eliminating turbulent areas in the valve casing and a venturi inlet for increasing the velocity of flow at the minor bore diameter to overcome the resistance of an obturator, the flanged body having an internal angled seating at the base of the bore for a solid valve face and below this valve a second valve seating for a flexible valve.

The second part of the assembly is an oscillating valve with guide fins operating within the bore of a flanged body and guide surfaces at the base.

The body has an elastomeric '0' ring valve for the first sealing with a solid valve face at the base of the guide fins for a secondary valve sealing.

A compression spring (part 3) housed in the base of the oscillating valve rests on the base of a guide cage (part 4) with vertical legs and a matching flange to the body (part 1). External dimples on part 1 locate in a dimple recess on part 4 and locks-the units together during assembly. To avoid valve adherence at high temperature and pressures, the body part 1 can be made in various materials with differing lengths and internal diameters to suit alternative inlet bores, and pipe sizes.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1. shows a vertical cross connection of a non-return valve sub-assembly in a closed position within a guide cage.

Figure 2. illustrates the valve in the open position and the flow areas between the guide legs.

Figure 3. shows a section of a flanged body and Venturi inlet as part 1 of an exploded view of the sub-assembly.

Figure 4. shows a section of an oscillating valve body with elastomeric '0' ring valve as part 2.

Figure 5. shows a compression ring as part 3.

Figure 6. shows a cross section through the guide cage and buffer stop part 4.

Referring to the drawing the non-return valve sub-assembly Figure 1, comprised of four parts with the first part a valve body 10. Figure 3 with an external flange 11 for incorporating in valve bodies or casings Figures 7 and 8. The body 10 having external surfaces that eliminate turbulent areas during flow and a Venturi inlet for increasing velocity and pressure at the obturator 14 has a major diameter 12 and a minor diameter 13, being the internal bore diameter of the valve. Below the bore diameter 14 an angled valveseating transmits high pressure through the flange 11 to the valve casing when an elastomeric '0' ring 24 is compressed against a valve seating 16 until a secondary valve face 22 of an oscillating valve 20 (Part 2, Figure 4) is urged into contact with valve seating 15.On the external face of the body 10 spigot are preformed dimples 18 which secure the assembed parts when located in a dimple recess 39 (Part 4 Figure 6) The oscillating valve 20 has guide fins 21 attached to a domed top which operate within the bore diameter 14 and at the base of the fins 21 is a valve face 22 matching the valve seating 15 of the body 10. Within a recessed groove 23 an elastomeric '0' ring valve 24 is located with the base of the groove extending to act as a guide surface 26 within a guide cage 34 (Part 4 Figure 6). The base of the valve 20 has a shouldered blind aperture 27 in which is housed a compression spring 30 (Part 3 Figure 5), the aperture terminating in an angular buffer stop 28 limiting the travel of the oscillating valve 20.The base of the compression spring 30 is located in a channel 32 of base section 33 of the guide cage 34, the channel surrounding a hollow domed buffer stop 35. Attached to the base section 33 are three or more horizontal legs 36 (according to valve size) which are continued at right angles to the base to form vertical legs 37 terminating in a flange 38 matching the diameter of the body flange 11 with flange 38 having an internal dimple recess 39. In Figure 7 the valve body 10 is shown as a standard part but in Figure 8 the body 10 is shown as a purpose made Venturi PMV part to fit the particular size of the valve casing inlet 42. obliterating crevices creating turbulence and where valve adherence can take place due to high pressures and temperatures the body 10 (Part 1 Figure 3) can be made in differing materials with the fail-safe valve seating 15 for the rigid valve 22 and the valve seating 16 for the flexible valve 24 providing repellent surfaces with the remaining part of the sub-assembly remaining constant. PMV - Purpose Made Venturi.

Claims

1. A non-return valve assembly of four parts when locked together can be integrated in valve casings of various types and configurations with inlet and outlet bores for inclusion in a fluid flow line.

2. A non-return valve assembly-as claimed in Claim 1 wherein the first of four parts being a valve body with an external flange for incorporating in a valve body or casing having pipe connections.

3. A non-return valve assembly as claimed in Claim 1 wherein the first part has an inlet section for the prevention of turbulence in a valve casing and an internal venturi surface with major and minor diameters for increasing flow velocity at the point of impact against and around a valve obstructor.

4. A non-return valve assembly as claimed in Claim 1 wherein the first part has an angled seating at the base of the bore for a solid valve and below this a second valve seating for an elastomeric valve.

5. A non-return valve assembly as claimed in Claim 1 wherein the first part has a spigot on which are a series of external dimples that when impressed into a dimple recess within an internal surface a fourth part locks the units together during assembly.

6. A non-return valve assembly as claimed in Claim 1 wherein the second part of the assembly is an oscillating valve with guide fins for vertical operation within the diameter of the inlet bore of part 1, a solid valve face for secondary sealing, an elastomeric 0 ring valve retained in an annular groove and a solid valve base larger than the diameter of the 0 ring which restricts excessive lateral movement when oscillating between guide legs of part 4, the base having a shouldered blind aperature housing a compression spring.

7. A non-return valve as claimed in Claim 6 wherein the third part is a loaded compression spring housed in the base of oscillating valve part 2 with the opposite end secured within a channel of part 4.

8. A non-return valve as claimed in preceding claims wherein the fourth part is a guide cage with vertical legs, a matching flange to part 1 with an internal dimple recess, a hollow domed buffer stop and channel to house the spring.

9. A non-return valve as claimed in preceding claims wherein the four parts when assembled and worked together as a sub unit assembly can be integrated in single or double valve casings of various configurations but in particular as a replacement sub-assembly in valve casings described in current Patent No 2179121.

10. A non-return valve sub assembly substantially described herein with reference to figures 1 to 8 of the accompanying drawings.