GB2210140A

GB2210140A - A non-return valve

Info

Publication number: GB2210140A
Application number: GB8807558A
Authority: GB
Inventors: Michele Barberi
Original assignee: BARBERI ALDO
Current assignee: BARBERI ALDO
Priority date: 1987-09-24
Filing date: 1988-03-30
Publication date: 1989-06-01
Anticipated expiration: 2008-03-30
Also published as: IT8722419V0; GB8807558D0; IT211836Z2; GB2210140B

Abstract

A non-return valve comprising a valve body (10) defining a main fluid passage having an inlet end (26) and an outlet end (28) and provided with first and second discharge outlets (12, 20) and first and second valve members (34, 36) movable on coaxial annular support means (24, 30, 32) between open and closed positions to open or block the main fluid flow passage. The valve members (34, 36) are urged towards their closed positions by spring means (42, 44) the spring force of which is overcome by fluid passing through the main fluid flow passage from the inlet end to the outlet end thereof. <IMAGE>

Description

A NON-RETURN VALVE This invention relates to a non-return valve cf the type used in particular for domestic or industrial hydraulic plumbing.

It is known that the primary function of an hydraulic non-return valve is to regulate the direction of the flow of fluid passing through it so as to provide minimum resistance to the passage of fluid in one direction and te impede fluid flow in the opposite direction. In domestic and industrial plumbing this function is of primary importance as it prevents the return into the water supply of any polluted or contaminated liquids which may be present in the hydraulic system due to a drop in pressure.

Non-return valves which carry cut this function are technically known. For example one known type of nonreturn valve is provided with double closing in that the valve has two valve members. However these valve members are arranged to open in a different direction in respect of the entry and exit flow of the liquid giving rise in use to high and undesired pressure losses due to the twisting passage through which the liquid has to pass.

Other types of non-return valve are also known in which the opening of the valve members is n the same direction as the liquid flow through the valve and so do not have the inconvenience of loss of pressure when the valves are opened. However the valve members travel on (i.e. are movably guided by) tracks formed, for example, from reliefs on the internal wall of the valve body, and are easily subject to jamming during travel.

Both types of known non-return valve described above are equipped with a discharge outlet on the valve body to enable minimum amounts of liquid to be obtained, for analysis purposes, even when the hydraulic system is in use. However neither of these known non-return valves is fitted with a discharge outlet having a sealing plug to allow emptying of the system with the aim, for example, of preventing freezing of the liquid in the pipes and the consequent bursting of the same.

The present invention seeks to obviate the abovementioned inconveniences by providing a non-return valve with double closing in which the loss of fluid pressure in use is minimised and in which it is possible both to remove minimum quantities of liquid, even when the system is in use, and, if necessary, to empty completely the system with the valve members closed.

According to the present invention a non-return valve comprises a valve body defining a main fluid flow passage having an inlet end and an outlet end, the valve body being provided with first and second discharge outlets opening into the said main fluid flow passage and first annular support means within the said main fluid flow passage, a fluid flow inlet member connected to the said inlet end of the main fluid flow passage and including second annular support means, a fluid flow outlet member connected to the said outlet end of the main fluid flow passage and including third annular support means, the said annular support means being coaxial with each other, first and second valve members movably supported by the said annular support means within said main fluid flow passage for movement between a passage-blocking closed position and an open position, and first and second spring means associated with said first and second valve members, respectively, and arranged to provide valve closing forces which are overcome in use by the passage of fluid through the valve passage from said inlet end to said outlet end.

The positioning of the valve members enables operation without risk of jamming and the design of the valve minimises the pressure loss of the liquid flowing through the valve.

Conveniently the first discharge outlet is closed by a screw-threaded plug having a conical end, unscrewing of the plug enabling minimum quantities of liquid to be discharged even when the system is in operation. The second discharge outlet is conveniently closed by a sealing plug, also accessible outwardly of the valve body and suitably positioned downstream of the second valve member, in respect of the direction of flow, to enable the hydraulic system to be emptied when the valve members are in their closed positions.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawing, the single figure of which shows an axial sectional view of a non-return valve according to the present invention.

The non-return valve illustrated in the enclosed drawing includes a valve body 10 comprising a single metal alloy block formed by casting or hot pressing in the form of a substantially hollow cylinder.

The valve body 10 is equipped with an outwardly opening first discharge outlet 12 which is closed by a screw-threaded plug 14 having a conical end portion. The plug 12 has a transverse channel 16 rearwardly of its conical end portion and which typically extends diametrically from side to side of the plug and a longitudinal channel 18, typically extending axially of the plug 12, which communicated at its front end with the transverse channel 16 and which extends to the rear end of the plug.

The plug is unscrewable to allow a minimum amount of liquid to be discharged through the plug 14 via the channels 16 and 18 even during use of the hydraulic system. An outwardly opening second discharge outlet 20 is closed by an unscrewable sealing plug 22, unscrewing of the plug 22 enabling emptying of the fluid present in the system even with the valve closed.

The valve body 10 is fitted internally with a first annular support 24 in the form of a spider. Fluid flow inlet and outlet members, in the form of pipe couplings 26 and 28 are connected to the inlet and outlet ends, respectively, of the valve body 10. By way of example (and as shown) the pipe couplings 26 and 28 are threadedly connected to the valve body and enable the valve to be connected upstream and downstream with a water system and an hydraulic plant. The pipe couplings 26 and 28 are fitted internally with second and third annular supports 30 and 32, each in the form of spiders and both being coaxial with the first annular support 24. Each spider-like support 24 (30,32) conveniently has four equally spaced apart supporting legs 24a (30at32~) and a cylindrical guide 24b (30b,32b).

Two valve members 34 and 36 are axially mounted within the valve, the annular supports 24, 30 and 32 serving to guide axial movements of these valve members 34 and 36.

Each valve member comprises a central disc carrying an annular sealing member, e.g. in the form of a rubber ring or gasket, and axially extending stems 38 and 40 on either side of the central disc. As shown the stems of the valve member 34 are slidably received in the annular supports 24 and 30 and the stems of the valve member 36 are slidably received in the annular supports 24 and 32. Thus each valve member 34, 36 is movable between an open position and a passage-blocking or closed position. In the closed position, the sealing member of valve member 34 seats against an annular, axially facing seating surface of the pipe coupling 26 and the sealing member of the valve member 36 seats against an annular, axially facing seating surface formed internally in the valve body 10. A spiral spring 42 is positioned between the central disc of the valve member 34 and the annular support 24. A second spiral spring 44 is positioned between the central disc of the valve member 36 and the annular support 32. These springs 42 and 44 are used to ensure the return of the valve members 34, 36 to their closed positions when the pressure of the fluid coming from the water system ceases and are designed to create a minimum pressure to be overcome by the fluid passing through the valve in the direction indicated by the arrow.

From the above it will be clear that the desired aims of the invention are achieved by the following features or characteristics of the valve: (a) the two valve members operate at the same time but separately thus giving a greater operating guarantee of the non-return valve since, in the case of wear of one of the valve members, the other one will continue to ensure the operation of the valve.

(b) The coaxial assembly of the valve members and their opening in the direction of the entry and exit of the flow of fluid (as indicated by the arrow) ensures a reduction of the loss of pressure of the fluid itself thus giving an improved pressure efficiency.

(c) The sliding movement of the valve members inside the annular supports is free of problems thus avoiding any possibly jamming.

(d) The presence of the discharge outlet 12 closed by the plug 14 allows minimum quantities of fluid to be taken from the hydraulic system when in use for analysis purposes, either with the valve members in their open or closed positions.

(e) The presence of the discharge outlet 20 with a sealing plug 22 placed downstream from the second valve member 36 in respect of the direction of the fluid allows the liquid contained in the pipes of the hydraulic plant to be discharged with the valve closed whenever required to avoid freezing.

Claims

1. A non-return valve comprising a valve body defining a main fluid flow passage having an inlet end and an outlet end, the valve body being provided with first and second discharge outlets opening into the said main fluid flow passage and first annular support means within the said main fluid flow passage, a fluid flow inlet member connected to the said inlet end of the main fluid flow passage and including second annular support means, a fluid flow outlet member connected to the said outlet end of the main fluid flow passage and including third annular support means, the said annular support means being coaxial with each other, first and second valve members movably -supported by the said annular support means within said main fluid flow passage for movement between a passageblocking closed position and an open position, and first and second spring means associated with said first and second valve members, respectively, and arranged to provide valve closing forces which are overcome in use by the passage of fluid through the valve passage from said inlet end to said outlet end.

2. A valve according to claim 1, in which the first valve member is movably supported by the first and second annular support means and the second valve member is movably supported by the said first and third annular support means.

3. A valve according to claim 1 or 2, in which the said annular support means comprise spider guides.

4. A valve according to any one of claims 1 to 3, in which the fluid flow inlet member has a first valve seat for seating the first valve member when the latter is in its closed position and in which the valve body has a second valve seat for seating the second valve member when the latter is in its closed position.

5. A valve according to any one of the preceding claims, in which each valve member comprises a head carrying a gasket and stems extending on opposite sides of the head, the stems being received within said annular supports to slidably guide the valve members during movement of the valve members between their open and closed positions.

6. A valve according to claim 4 and 5, in which said first and second valve members carry, respectively, first and second sealing gaskets arranged to seal against the first and second valve seats, respectively, when the valve members are in their closed positions.

7. A valve according to any one of the preceding claims, in which the said first discharge outlet is closed by a screw-threaded first plug having a conical front end for sealing against a part of the discharge outlet when the plug is fully screwed in, the plug also having a discharge channel with a transverse first portion and a longitudinal second portion.

8. A valve according to any one of the preceding claims, in which the said second discharge outlet is closed by a screw-threaded second plug.

9. A valve according to claim 4 or 6 or claim 7 or 8 when dependent on claim 4 or 6, in which the said second discharge outlet is arranged downstream of the said second valve seat with respect to the intended direction of fluid flow through the valve passage.

10. A valve according to any one of the preceding claims, in which the said first spring is positioned between the first valve member and the first annular support means.

11. A valve according to any one of the preceding claims, in which the said second spring is positioned between the second valve member and the third annular support means.

12. A valve according to any one of the preceding claims, in which the valve body comprises a block of metal alloy of hollow substantially cylindrical form.

13. A non-return valve constructed and arranged substantially as herein described with reference to, and as illustrated in, the accompanying drawing.