GB2233429A

GB2233429A - Fluid control valves

Info

Publication number: GB2233429A
Application number: GB9014281A
Authority: GB
Inventors: Robert Stewart Dougan; Alan Donald Burgess
Original assignee: SUNVIC CONTROLS Ltd
Current assignee: SUNVIC CONTROLS Ltd
Priority date: 1989-06-30
Filing date: 1990-06-27
Publication date: 1991-01-09
Anticipated expiration: 2010-06-27
Also published as: GB8915058D0; GB9014281D0; GB2233429B

Abstract

A fluid control valve is provided with a rotatable shoe member (44). The shoe member is provided with a centrally located triangular hump (52) and a single thin sealing rim (54). The hump is provided to move the valve shoe radially inwards against the action of a compression spring (50) when the valve shoe is rotated to the open position of the valve in order to lift the sealing rim clear of the wall of the valve housing. In an alternative embodiment, the shoe member includes a pair of humps and is attached to a rotatable shaft via a leaf spring. <IMAGE>

Description

"IMPROVEMENTS IN FLUID CONTROL VALVES" The present invention relates to fluid control valves, more particularly of the type used in domestic central heating systems.

One known type of fluid control valve is shown in Fig. 1 of the accompanying drawings. The valve shown is of the T-junction type having one inlet 10 and two diametrically opposite outlets 12 and 14. The valve member itself is in the form of a segmented shoe member 16 having a part cylindrical surface 18 adapted to match the inner cylindrical surface of the valve housing 20. Each outlet 12 and 14 has a respective port 22 and 24 in the cylindrical wall of the housing 20 which can be completely closed by the cylindrical surface 18 of the valve member 16.The valve shoe member 16 is coupled to an operating shaft 26 for rotation therewith via a shaft 28 provided with a compression spring 30, the valve shoe member 16 being arranged to be urged in a radially outward direction with respect to the operating shaft 26, so that its cylindrical surface 18 makes good contact with the inner cylindrical wall of the housing 20 and also seals either one of the outlet ports 22 and 24 against escape of fluid when in position.

The disadvantage of the above described type of fluid control valve is that sometimes extraneous particles in the fluid get trapped between the cylindrical surface 18 and the inner cylindrical wall 20 of the housing. This can then cause a certain seepage of fluid to an outlet when that outlet is supposed to be shut.

Moreover, if abrasive materials get trapped, they can seriously damage the cylindrical surface of both the valve member 16 and the inner wall of the housing 20.

It is therefore an object of the present invention to partially or wholly overcome the above mentioned disadvantages.

According to the present invention there is provided a fluid control valve having a housing, an inlet port and at least one outlet port, and a valve shoe rotatable within the housing between at least two positions, one of which closes said at least one outlet port, wherein said valve shoe has peripheral sealing means for sealing against the inner wall of the valve housing, and means for lifting said sealing means away from the wall of the valve housing when the valve shoe is moved from a position where it closes an outlet port to a position where the outlet port is open.

Said lifting means may be a centrally located triangular hump or pair of pyramidal humps provided on the sealing surface of the valve shoe.

The present invention will now be described in greater detail by way of example with reference to the remaining figures of the accompanying drawings, wherein: Fig. 2 is a diagrammatic plan view of a fluid control valve having a valve shoe constructed in accordance with the present invention; Fig. 3 is a perspective view of the valve shoe shown in Fig 2; Fig. 4 is a perspective view of an alternative form of valve shoe; and Fig. 5 is a front view of the valve shoe shown in Fig. 4.

Referring first to Figs. 2 and 3, the fluid control valve disclosed has outlet ports 40 and 42. The inlet port is not shown being underneath as shown in Fig.

1. A valve shoe member 44 is slidably located on a rod 46 fixed to an operating shaft 48, rotatable through 90C so that the valve shoe member 44 is either in the closed position shown in full lines or in the open position shown in dotted lines. The valve shoe member 44 is urged radially outwards with respect to the operating shaft 48 by means of a compression spring 50.

As shown in Fig. 3 the valve shoe member 44 has a centrally located hump 52 which is triangular shaped as shown and a single thin sealing rim 54 provided around the periphery of the shoe member. The sealing rim 54 may be either formed with the same plastic material as the shoe or may be a rubber based material which is affixed to the shoe member by suitable adhesive, or over-moulded.

The purpose of the central hump 52 is to move the valve shoe 44 radially inwards towards the operating shaft 48 against the action of the compression spring 50, when the valve shoe is rotated from the closed position as shown in full lines to the open position as shown in dotted lines, this action being achieved by the apex of the hump 52 contacting the inner circumferential wall of the valve housing 41. As a result the sealing rim 54 of the valve shoe 44 is lifted clear of the wall of the valve housing which will release any dirt or grit which has become trapped between the rim 54 and the inner wall of the valve housing 41. It also ensures that scuffing wear is minimized and that fluid flow washes any particles which may become stuck to the sealing rim 54.

It should also be noted in this construction that the sealing contact area of the rim 54 is smaller than with the conventional construction shown in Fig. 1, so that in any case it is less liable to trap dirt or grit. Moreover, the seal force per unit contact area is substantially increased thus improving the effective seal of the control valve.

Referring now to the modified construction of valve shoe shown in Figs. 4 and 5, a valve shoe member 64 is fixed to an operating shaft 68 by means of a flexible strip 66 in the form of a leaf spring the centre part of which is sandwiched between two washers 67 and stake rivetted to secure to the bottom of the shaft 68.

As shown in Fig. 5, the valve shoe member 64 has a pair of centrally located humps 72 and 73 which are substantially pyramidal in shape and a single thin sealing ring 74 provided around the periphery of the shoe member.

The sealing ring 74 may either be of the same construction as in the previous embodiment or it may be constituted by a softer material than the two humps 72 and 73 of the shoe member.

Securing lugs 75 are provided on either side of the shoe member 64 to enable it to be secured to the flexible strip 66. It can conveniently be detached for cleaning or replacement when required.

The operation is the same as that of the first embodiment except that the resiliency of the leaf spring acts as the spring 50, to urge the shoe member to make sealing contact with the inner wall of the valve.

Although the above examples relate to a three port construction as shown in Fig. 1 other configurations are possible, e.g. a two port construction where the inlet and outlet ports are diametrically opposite one another.

The invention is also applicable to a three port construction where the inlet port is at right angles to both outlet ports in the same plane thereof. Furthermore, the shaft 48 or 68 of the two embodiments can be adapted to carry a second shoe member at 90O to the first one, so that in the case of a three port construction flow can be directed to either one of the outlet ports, or both ports simultaneously.

The above described constructions are applicable to control valves controlling the flow of either gases or liquids. In particular the above constructions are applicable to control valves for domestic central heating systems.

The novel constructions of the peripheral seal and centrally located hump or pair of humps thus ensures the control valve has a longer trouble free life, than the conventional construction of valve shoe shown in Fig. 1.

Claims

CLAIMS:

1. A fluid control valve having a housing, an inlet port and at least one outlet port, and a valve shoe rotatable within the housing between at least two positions, one of which closes said at least one outlet port, wherein said valve shoe has peripheral sealing means for sealing against the inner wall of the valve housing, and means for lifting said sealing means away from the wall of the valve housing when the valve shoe is moved from a position where it closes an outlet port to a position where the outlet port is open.

2. A fluid control valve according to claim 1, wherein said lifting means is a centrally located triangular hump provided on the sealing surface of the valve shoe.

3. A fluid control valve according to claim 1; wherein said lifting means is a pair of centrally located pyramidal humps provided on the sealing surface of the valve shoe.

4. A fluid control valve according to any one of the preceding claims, wherein said sealing means is a single thin sealing rim provided around the periphery of the shoe member.

5. A fluid control valve according to claim 4, wherein the sealing rim is made of the same material as the shoe member.

6. A fluid control valve according to claim 5, wherein said material is a plastics material.

7. A fluid control valve according to claim 4, wherein the sealing rim is made of a rubber based material or other material which is softer than the material of the shoe member.

8. A fluid control valve constructed substantially as herein described with reference to and as illustrated in Figs. 2 and 3, or Fig. 2 as modified by the construction of the shoe member shown in Figs. 4 and 5.