GB2147667A

GB2147667A - An annular sealing element

Info

Publication number: GB2147667A
Application number: GB08420255A
Authority: GB
Inventors: Luc Joly
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-10-03
Filing date: 1984-08-09
Publication date: 1985-05-15
Also published as: FR2552839B3; FR2552839A1; GB8420255D0

Abstract

An annular sealing element, intended to be clamped between two parallel surfaces, comprises two branches (2) disposed in a V shape. The branches (2) terminate at contact surfaces (3) which are rounded. <IMAGE>

Description

SPECIFICATION An annular sealing element This invention relates to an annular sealing element which is intended to be clamped between two parallel surfaces to provide a sealed enclosure for high or low temperature fluids.

Known sealing elements for this purpose have two branches disposed in the shape of a V. The parts of the free ends of the two branches which are to come into contact with the two surfaces between which there must be sealing tightness are in the form of two plane faces which, when the element is clamped, are parallel. These faces, like the two surfaces with which they are to come into contact, must be polished with a high degree of precision in order to achieve good surface contact.

In view of this surface contact, it is necessary, in order to achieve a required contact pressure to establish sealing, to apply a great clamping force to the element between the two surfaces. In order to be able to apply this clamping force without excessive deflection of the sealing element, it is necessary to make the element relatively rigid.

Nevertheless, this rigidity must be limited in order for the element to have some degree of flexibility which is necessary to compensate for any differences or variations of the distance between the two surfaces between which the element must seal. These differences or variations may be due, for example, to manufacturing tolerances or to thermal expansions. Now, in the event of deflection of the element, the two plane opposing faces of the free ends of the branches of the V do not maintain their parallel position, which gives rise to excessive pressures on the edges, resulting in a risk of damage to the surfaces in contact and sealing problems.

It would appear, therefore, that the compromise solution hitherto advocated in order to satisfy the contradictory requirements relating to known Vshaped sealing elements is not satisfactory.

According to the present invention there is provided a sealing element which, in use, is clamped between two parallel surfaces, the element having two branches which are each provided with rounded contact surfaces at their free ends for engagement, respectively, with the parallel surfaces.

Thanks to the rounded contact surfaces, linear contact is established between the sealing element and the two surfaces between which it must seal.

A contact pressure which endures sealing may thus be established by a clamping force which is less than is required in the case of surface contact.

This linear contact does not require, for the surfaces which are in contact, a precision which is as great as surface contact. Finally the linear contact between the rounded contact surfaces and the adjacent plane surfaces is also maintained in the event of any variation in the deflection of the element, the rounded surfaces rolling on the adjacent plane surfaces. This characteristic and also the possibility of establishing sufficient contact pressure with a reduced clamping force on the element allows a less rigid, for example less solid, element to be used.

An embodiment in accordance with the present invention thus provides a sealing element which can be distinguished from known elements of the same type by a reduced cost price, by improved sealing in spite of a reduced clamping force, and by maintaining this tightness in the event of any variation in the distance separating the two surfaces between which the element must ensure sealing For a better understanding of the present invention and to show how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a cross section of a sealing element; and Figure 2 is an enlarged fragmentary view of part of the sealing element.

The annular sealing element 1 illustrated in Figure 1 is in the form of a diabolo, having two branches 2 defining a V and converging at an angle of, for example, 60 towards the axis of the element 1.

The element is to be clamped axially between two parallel surfaces, with the free outer ends of the two branches 2 of the V then being in contact with the two surfaces.

As shown in Figure 2 for one of the two branches 2, each branch 2 of the V has a rounded face 3 at that part of its free end which is to come into contact with the adjacent plane surface 4 indicated by a dot-and-dash line in Figure 2.

A linear contact is therefore established between the rounded face 3 and the plane surface 4 over the total circumference of the element 1.

This linear contact is not affected by variations in the inclination of the branches 2 relative to the surfaces 4. Such variations can result, for example, from an increase or reduction in the deflection of the joint (i.e. an increase or reduction in the angle at which the two branches 2 are inclined to each other) under the influence of variations in the distance between the two surfaces 4, for example in response to temperature changes. The rounded faces 3 are capable of rolling on the faces 4.

Preferably, the radius of curvature of the rounded faces 3 equals or exceeds the external diameter of the element.

The sealing element may be made from any material having a sufficient hardness so as not to be crushed under the clamping force applied, and having an elasticity which is such that the element can be bent at least in part elastically under this clamping force. In the example shown, the element is illustrated as being of metal, which is particularly advantageous in the event of very high or very low temperatures. It might alternatively be made, for example, of plastics material or of metal coated with plastics material.

Moreover, instead of having the illustrated shape where the apex of the V profile is inwardly directed, which is preferable for the case where the internal pressure is less than the external pressure, the element may have the reverse profile, i.e. the apex of the V profile may be outwardly directed, a preferabie solution when the internal pressure exceeds the external pressure.

Claims

1. An annular sealing element which, in use, is clamped between two parallel surfaces, the element having two branches which are each provided with rounded contact surfaces at their free ends for engagement, respectively, with the parallel surfaces.

2. A sealing element as claimed in claim 1, in which the branches are disposed in the form of a V.

3. A sealing element as claimed in claim 1 or 2, in which the contact faces have a radius of curvature which is not less than the external diameter of the element.

4. An annular sealing element substantially as described herein with reference to, and as shown in, the accompanying drawings.