GB2166501A - Sealing member - Google Patents

Abstract

An annular Sealing Member comprising a portion (21) which is part circular in cross section with a lip (22) extending therefrom. The lip seats in a groove of one of two members to be sealed and prevents the sealing ring from being blown out by fluid pressure. <IMAGE>

Description

SPECIFICATION Sealing member This invention relates to a sealing member.

According to the present invention a sealing member comprises a portion which is part circular in cross section with a lip extending therefrom. Preferably the member is generally annular.

Preferably the lip extends laterally from the part circular portion, and the lip is shaped on its inner side with a concave portion adjoining the part circular portion and a convex portion adjoining the concave portion.

Conveniently the outerside of the lip extends rearwardly and substantially tangentially. The part circular portion may extend over approximately 280 with the lip extending from the remaining 90 .

The invention may be performed in various ways and one specific embodiment will now be described in more detail with reference to the accompanying drawings in which: Figure 1 is a view of a conventional 0 ring assembly.

Figure 2 is a cross section through a sealing member according to the present invention.

Figure 3 is a view of a part of a sealing member according to the present invention in a groove and Figure 4 is a conventional self sealing valve assembly and with which a sealing member according to the present invention can be used.

In the valve assembly according to Fig. 4 there is shown a self sealing coupling, the operation of which is conventional and will not be described in detail, but only those parts relevant to an understanding of the present invention will be referred to.

The self sealing coupling comprises a left hand member 10 and a right hand member 11. On joining the two members the end face 12 of the left hand member 10 is abutted against a dirt excluder ring 14 of the right hand member. On pushing the two members together the dirt excluder ring assembly 14 on right hand member 11 is pushed rearwardly whilst a mushroom valve assembly 15 then pushes a piston 12A to the left past an O ring seal 18 until dirt excluder ring 14 abuts against abutment 16 which then causes sleeve 5 to move rearwardly opening an annular flow path with the head of mushroom valve 15 to a point where flow can take place between the two members of the coupling. In the left hand member 10 as mentioned there is an O ring seal with a conventional Teflon backing member 20.

When the members are uncoupled and whilst fluid is flowing there is a tendency for the flow of fluid to cause the 0 ring 18 to blow out of position.

If reference is now made to Fig. 1 which is an enlarged view of the 0 ring 18 it can be seen that as the piston 21A closes a drop of pressure occurs in the zone marked A. whilst pressure remains hihg in the zone marked B.

This has the effect of creating a pressure behind the 0 ring and it is believed that it is this pressure differential which causes the 0 ring to blow out.

If reference is now made to Figs. 2 and 3 it will be seen that there is shown a sealing member of a different shape. This member is in the form of an 0 ring indicated generally at 21 with a laterally extending lip 22. The lip is shaped on its inner face to have a radiussed concave portion 23 which then extends into a convex portion 24 and then a generally radially directed portion 25.

If reference is now made to Fig. 3 it will be seen that when this sealing member 21 is placed in position and the piston 12A is being closed, whilst there is still a depression in the zone marked A the zone this time referred to as C above the lip and which has higher pressure exerted on it will in this case tend to force the lip into engagement with the groove in which it sits. In Fig. 3 will be seen a number of arrows showing the direction of the applied pressure. In practice the lip is made such as to be an interference fit in the groove, and assumes the shape shown in Fig.

3.

Thus with the present invention it is possible to avoid the difficult6y of the sealing member being inadvertentely blown out.

Although the member has been described as annular it will be appreciated that in particular circumstances members of other shapes i.e. straight or whatever shape may be required can be provided, a lip being provided and which may also be of the desired shape.

1. A Sealing Member comprising a portion which is part circular in cross section with a lip extending therefrom.

2. A sealing member as claimed in claim 1 which is generally annular.

3. A sealing member as claimed in claim 2 in which the lip extends laterally from the part circular portion.

4. A sealing member as claimed in claim 3 in which the lip is shaped on its inner side with a concave portion adjoining the part circular portion and a convex portion adjoining the concave portion.

5. A sealing member as claimed in claim 4 in which the outer side of the lip extends rearwardly and generally tangentially.

6. A sealing member as claimed in any one of claims 1 to 5 in which the part annular portion extends over approximately 270 with the lip extending from the remaining 90 .

7. A sealing member substantially as described herein with reference to and as shown in Figs. 2 to 4 of the accompanying drawings.

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

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Sealing member This invention relates to a sealing member. According to the present invention a sealing member comprises a portion which is part circular in cross section with a lip extending therefrom. Preferably the member is generally annular. Preferably the lip extends laterally from the part circular portion, and the lip is shaped on its inner side with a concave portion adjoining the part circular portion and a convex portion adjoining the concave portion. Conveniently the outerside of the lip extends rearwardly and substantially tangentially. The part circular portion may extend over approximately 280 with the lip extending from the remaining 90 . The invention may be performed in various ways and one specific embodiment will now be described in more detail with reference to the accompanying drawings in which: Figure 1 is a view of a conventional 0 ring assembly. Figure 2 is a cross section through a sealing member according to the present invention. Figure 3 is a view of a part of a sealing member according to the present invention in a groove and Figure 4 is a conventional self sealing valve assembly and with which a sealing member according to the present invention can be used. In the valve assembly according to Fig. 4 there is shown a self sealing coupling, the operation of which is conventional and will not be described in detail, but only those parts relevant to an understanding of the present invention will be referred to. The self sealing coupling comprises a left hand member 10 and a right hand member 11. On joining the two members the end face 12 of the left hand member 10 is abutted against a dirt excluder ring 14 of the right hand member. On pushing the two members together the dirt excluder ring assembly 14 on right hand member 11 is pushed rearwardly whilst a mushroom valve assembly 15 then pushes a piston 12A to the left past an O ring seal 18 until dirt excluder ring 14 abuts against abutment 16 which then causes sleeve 5 to move rearwardly opening an annular flow path with the head of mushroom valve 15 to a point where flow can take place between the two members of the coupling. In the left hand member 10 as mentioned there is an O ring seal with a conventional Teflon backing member 20. When the members are uncoupled and whilst fluid is flowing there is a tendency for the flow of fluid to cause the 0 ring 18 to blow out of position. If reference is now made to Fig. 1 which is an enlarged view of the 0 ring 18 it can be seen that as the piston 21A closes a drop of pressure occurs in the zone marked A. whilst pressure remains hihg in the zone marked B. This has the effect of creating a pressure behind the 0 ring and it is believed that it is this pressure differential which causes the 0 ring to blow out. If reference is now made to Figs. 2 and 3 it will be seen that there is shown a sealing member of a different shape. This member is in the form of an 0 ring indicated generally at 21 with a laterally extending lip 22. The lip is shaped on its inner face to have a radiussed concave portion 23 which then extends into a convex portion 24 and then a generally radially directed portion 25. If reference is now made to Fig. 3 it will be seen that when this sealing member 21 is placed in position and the piston 12A is being closed, whilst there is still a depression in the zone marked A the zone this time referred to as C above the lip and which has higher pressure exerted on it will in this case tend to force the lip into engagement with the groove in which it sits. In Fig. 3 will be seen a number of arrows showing the direction of the applied pressure. In practice the lip is made such as to be an interference fit in the groove, and assumes the shape shown in Fig. 3. Thus with the present invention it is possible to avoid the difficult6y of the sealing member being inadvertentely blown out. Although the member has been described as annular it will be appreciated that in particular circumstances members of other shapes i.e. straight or whatever shape may be required can be provided, a lip being provided and which may also be of the desired shape. CLAIMS

1. A Sealing Member comprising a portion which is part circular in cross section with a lip extending therefrom.

2. A sealing member as claimed in claim 1 which is generally annular.

3. A sealing member as claimed in claim 2 in which the lip extends laterally from the part circular portion.

4. A sealing member as claimed in claim 3 in which the lip is shaped on its inner side with a concave portion adjoining the part circular portion and a convex portion adjoining the concave portion.

5. A sealing member as claimed in claim 4 in which the outer side of the lip extends rearwardly and generally tangentially.

6. A sealing member as claimed in any one of claims 1 to 5 in which the part annular portion extends over approximately 270 with the lip extending from the remaining 90 .

7. A sealing member substantially as described herein with reference to and as shown in Figs. 2 to 4 of the accompanying drawings.

8. A coupling including a sealing member as claimed in any one of the preceding claims.