GB2287085A

GB2287085A - Non-return valve

Info

Publication number: GB2287085A
Application number: GB9404269A
Authority: GB
Inventors: Allan Grainger
Original assignee: Actis SARL
Current assignee: Actis SARL
Priority date: 1994-03-05
Filing date: 1994-03-05
Publication date: 1995-09-06
Also published as: GB9404269D0

Abstract

A non-return, valve, in particular for use in pumping and dosing apparatus in the food-processing industry, comprises a valve chamber (1) having a fluid inlet (5) and a fluid outlet (7). A guide (8) is fixedly disposed within the chamber (1) and permits movement of a valve closure member (9) between a valve closing position in which the closure member (9) sealingly engages the inlet (5) and a valve opened position in which the closure member (9) is displaced from the inlet (5). The guide (8) includes an abutment (81) which carries a plastics cushion (10) for limiting movement of the closure member (9) away from the inlet (5). <IMAGE>

Description

Title - Valve This invention relates to a stop valve, in particular to a stop valve suitable for applications in which the valve is repeatedly opened and shut.

In many applications, fluids are dosed into receptacles. An example is the food-processing industry in which aliquots of liquid, for instance brine, are dosed into cans of, say, soup or vegetables. The pumping and dosing apparatus used normally incorporates a stop valve. Such a stop valve conventionally comprises a valve member which is urged into engagement with a valve seat by a compression spring. The valve is opened by the pressure of fluid acting on the valve member, against the action of the spring, when the pump is actuated.

Known valves of this type suffer from a number of disadvantages. The valve member is subject to considerable wear, and may become misaligned. This results in the valve becoming ineffective.

There has now been devised an improved form of mechanical stop valve which overcomes or substantially mitigates the abovementioned disadvantages.

According to the invention, there is provided a valve comprising a valve chamber having a fluid inlet and a fluid outlet formed therein, on a fluid flow axis, guide means fixedly disposed within said chamber so as to define a fluid flow path between the wall of said chamber and said guide means, said guide means permitting movement of a valve closure member along said fluid flow axis between a valve closing position in which said valve closure member sealingly engages said fluid inlet and a valve-opened position in which said valve closure member is displaced from said fluid inlet and said fluid inlet and said fluid outlet are in fluid communication along said fluid flow path.

The valve according to the invention is advantageous primarily in that it is of relatively simple construction, and is reliable in use.

The valve chamber is preferably generally cylindrical, the fluid inlet and fluid outlet being located, normally centrally, in the end faces of the cylinder.

The valve closure member is preferably a ball, and the guide means is preferably a cylindrical tube of internal diameter slightly greater than the diameter of the ball. The cylindrical tube preferably depends from the end of the valve chamber which includes the fluid outlet, and preferably terminates a short distance (less than the diameter of the ball) above the fluid inlet.

The cylindrical tube preferably includes an internal rib or other projection to limit displacement of the ball from the fluid inlet. Upstream of the rib or other projection, the cylindrical tube is preferably provided with one or more apertures, eg slots, which permit flow of fluid to the fluid outlet. The fluid flow path thus comprises the spacing between the fluid inlet and the cylindrical tube, the space between the cylindrical tube and the wall of the chamber, and the apertures in the cylindrical tube.

The fluid inlet (which constitutes the valve seat) is preferably provided with a valve seal of plastics material.

This improves the effectiveness of the seal between the ball and the fluid inlet, and also reduces or eliminates the sound generated by engagement of the ball with the fluid inlet.

Likewise, the rib or other projection which limits displacement of the ball is preferably provided with a plastics cushion. In use, the ball thus reciprocates between engagement with the plastics valve seal and the plastics cushion, and is virtually silent in operation.

The plastics valve seal preferably provided on the fluid inlet, and the plastics cushion preferably provided on the displacement-limiting projection within the cylindrical guide tube, both preferably have a simple clip fitting.

According to a particularly preferred aspect of the invention, there is thus provided a valve comprising a generally cylindrical chamber, a fluid inlet and a fluid outlet being formed coaxially in respective opposite first and second end faces thereof, a cylindrical guide tube depending from said second end face, said cylindrical guide tube enclosing a freely moveable ball, the cylindrical guide tube terminating a distance less than the diameter of the ball from the first end face and being provided with an annular internal rib such that the ball may reciprocate freely between the fluid inlet and the annular internal rib, and the cylindrical guide tube being provided, upstream of said annular internal rib, with one or more apertures such that, in use, fluid may flow from the fluid inlet, externally of the cylindrical guide tube and through said apertures to said fluid outlet.

As explained above, the fluid inlet and the annular rib are each preferably provided with a plastics seal or cushion.

The invention will now be described in greater detail, by way of illustration only, with reference to the accompanying drawings, in which Figure 1 is a sectional side view of a valve according to the invention; and Figure 2 is a sectional view along line II-II in Figure 1.

Referring to Figure 1, a valve for use in a brine pumping and dosing apparatus for food-processing applications comprises a cylindrical chamber 1. A circular base plate 2 has an interference fit with one end of the chamber 2. In use, the valve is held fixedly between surrounding components (not shown) and the interference fit between the chamber 1 and base plate 2 is sufficient. In other applications other means may be provided for ensuring secure connection of the base plate to the chamber. The opposite end of the chamber 1 is closed by a top plate 3 which is secured by means of a circlip 4.

A fluid inlet 5 is formed centrally in the base plate 2. The fluid inlet receives a valve seal 6 of machined PTFE which defines the valve seat. The seal 6 is held in place by a circumferential rib 61 which locates in a corresponding groove provided in the wall of the fluid inlet 5.

A fluid outlet 7 is formed centrally in the top plate 3.

Depending downwardly from the outlet 7, and formed integrally with the top plate 3 is a cylindrical guide 8. The lower end of the guide 8 surrounds a ball 9 and the guide 8 is provided with an internal annular rib 81 to which is fitted a cushion 10, again of machined PTFE. The ball 9 is thus free to move along the longitudinal axis of the chamber 1 between a valve closing position (shown by the solid outline in Figure 1) in which the ball 9 engages the seal 6 and a valveopen position (shown by the broken outline in Figure 1) in which the ball 9 is displaced upwards.

The guide 8 is provided, at a position between the outlet 7 and the cushion 10, with three arcuate slots 82 (see Figure 2), each of which extends through approximately 80" of arc.

In use, the ball 9 reciprocates between the two positions shown in Figure 1. With the ball 9 initially in the valve closing position (solid line), when a pump (not shown) upstream of the valve is actuated the pressure of fluid on the ball 9 then the ball 9 is displaced into the valve-open position (broken line). Fluid flows through the inlet 5, around the outside of the guide 8, and through the slots 82 to the outlet 7. The lower edge of the guide 8 is rounded to prevent or reduce turbulence in the flow of fluid past it.

When the pressure of fluid is released, the ball 9 returns to the solid line position in Figure 1. This return is effected under the influence of gravity, and is assisted by any back pressure in the system which is applied to the ball 9 through a central bore 101 in the cushion 10.

The seal 6 and the cushion 10 reduce or eliminate the sound of the ball 9 impacting at each end of its travel. The valve is thus virtually silent in operation.

A further important advantage of the valve according to the invention is that it is self-priming. By this is meant that in an apparatus in which the brine header tank is positioned higher than the valve, when the pump is switched off the pressure of brine caused by gravity is sufficient to lift the ball 9 off the seal 6 sufficiently for the chamber 1 to charge with fluid. This is in contrast to known forms of stop valve in which the compression spring does not permit such charging of the valve chamber. The consequence of this is that, after a period of inoperation, eg overnight, the valve must be primed in a separate operation before normal use can resume.

Claims

1. A valve comprising a valve chamber having a fluid inlet and a fluid outlet formed therein, on a fluid flow axis, guide means fixedly disposed within said chamber so as to define a fluid flow path between the wall of said chamber and said guide means, said guide means permitting movement of a valve closure member along said fluid flow axis between a valve closing position in which said valve closure member sealingly engages said fluid inlet and a valve-opened position in which said valve closure member is displaced from said fluid inlet and said fluid inlet and said fluid outlet are in fluid communication along said fluid flow path.

2. A valve as claimed in Claim 1, wherein the valve chamber is generally cylindrical, the fluid inlet and fluid outlet being located in the end faces of the cylinder.

3. A valve as claimed in Claim 1 or Claim 2, wherein the valve closure member is a ball.

4. A valve as claimed in Claim 3, wherein the guide means is a cylindrical tube of internal diameter slightly greater than the diameter of the ball.

5. A valve as claimed in Claim 4, wherein the cylindrical tube depends from the end of the valve chamber which includes the fluid outlet, and terminates a distance less than the diameter of the ball above the fluid inlet.

6. A valve as claimed in Claim 4 or Claim 5, wherein the cylindrical tube includes an internal rib or other projection to limit displacement of the ball from the fluid inlet.

7. A valve as claimed in any one of Claims 4 to 6, wherein the cylindrical tube is provided, upstream of the rib or other projection, with one or more apertures which permit flow of fluid to the fluid outlet.

8. A valve as claimed in any preceding claim, wherein the fluid inlet is provided with a valve seal of plastics material.

9. A valve as claimed in Claim 6, wherein the rib or other projection which limits displacement of the ball is provided with a plastics cushion.

10. A valve as claimed in Claim 1, comprising a generally cylindrical chamber, a fluid inlet and a fluid outlet being formed coaxially in respective opposite first and second end faces thereof, a cylindrical guide tube depending from said second end face, said cylindrical guide tube enclosing a freely moveable ball, the cylindrical guide tube terminating a distance less than the diameter of the ball from the first end face and being provided with an annular internal rib such that the ball may reciprocate freely between the fluid inlet and the annular internal rib, and the cylindrical guide tube being provided, upstream of said annular internal rib, with one or more apertures such that, in use, fluid may flow from the fluid inlet, externally of the cylindrical guide tube and through said apertures to said fluid outlet.

11. A valve substantially as hereinbefore described and as illustrated in the accompanying figures.