Seals for gas isolators having multiple bias springs

Details Seals for gas isolators having multiple bias springs Seals for gas isolators having multiple bias springs

1990-06-22

1992-03-31

Cuchlinski, Jr., William A.

Fluid handling

Line condition change responsive valves

Direct response valves

137527, 137857, 251174, 251176, 277236, F16K 1114

Patent

active

050998862

DESCRIPTION:

BRIEF SUMMARY
This invention relates to seals for gas isolators, and in particular relates to an improvement in or modification of the type of seal described in British patent no. GB-2060824 and its equivalent U.S. Pat. No. 4,325,411.
GB-2060824 (U.S. Pat. No. 4,325,411) describes and claims a seal for a gas isolator which comprises a cantilever leaf spring to be attached to a fixed frame or a movable member of the isolator and a bias spring acting on the leaf spring, wherein the leaf spring is bent or curved when unstressed and wherein in the non-sealing position of the seal the bias spring makes only touch contact with the leaf spring, so that the leaf spring is unstressed in the said non-sealing position, whereby in the sealing position of the seal the stress induced in the bias spring will be the same as that induced in the leaf spring where the bias spring and the leaf spring have the same section modulus per unit length of seal.
We have now found that, on seals operating against the gas pressure, the addition of a second similar, but not identical, bias spring permits the reverse pressure sealing performance to be greatly improved.
Accordingly, the present invention provides a seal for a gas isolator which comprises a cantilever leaf spring to be attached to a fixed frame or a movable member of an isolator and a bias spring acting on the leaf spring, and further comprising a second similar, but not identical, bias spring acting on the first bias spring and therethrough on the said leaf spring.
Usually the leaf spring and the two bias springs will be clamped at the same point, and the tips (or free ends) of the bias springs will be so arranged that they act on the leaf spring essentially jointly at the point where the first bias spring bears against the leaf spring.
The bias springs will be, as is conventional, bent at a point along their length, one limb of the dual bias spring combination being clamped and the other limb of the bias spring combination bearing with its free end against the leaf spring. In the construction according to the invention the angle subtended by the two limbs of the additional bias spring will preferably be less than the angle subtended by the two limbs of the original bias spring, while the length of the said other limb of the additional bias spring (i.e. the limb that bears against the end region of the original bias spring that bears against the leaf spring) will preferably be less than the length of the corresponding limb of the original bias spring, the overall length of the two bias springs being substantially the same.
The invention will be further described by way of example only, with reference to the accompanying drawings, in which:
FIG. 1 shows a known gas isolator seal of the type described in GB-2060824 and U.S. Pat. No. 4,325,411;
FIG. 2 shows a preferred embodiment of a gas isolator seal according to the present invention; and
FIGS. 3a and 3b show in detail the original bias spring and the additional bias spring respectively of the seal according to FIG. 2.
The conventional seal illustrated in FIG. 1 is shown in its sealing position and essentially comprises a cantilever leaf spring 1 and a bias spring 2. The leaf spring is arranged to press against a cooperating member 3 which will be a fixed frame or a movable closure member of an isolator when the seal is in the sealing position as shown. The bias spring and the leaf spring are clamped against a support 4 which will be a movable closure member or a fixed frame of an isolator by clamp bars 5 and 6 respectively which in this case are each integral with respective support bars 7.
In this conventional seal a differential pressure effective in the direction of the arrow as shown in FIG. 1 tends to lift the seal off its seating 3, sometimes leading to undesired leakage of high pressure and possibly also corrosive gases.
The seal according to the invention illustrated in FIG. 2 differs from that illustrated in FIG. 1 by the provision of an additional bias spring 12, which is similar but not identical to the bias spring 2. In FI

REFERENCES:
patent: 735912 (1903-08-01), Schrotz
patent: 2000883 (1935-05-01), Cullen et al.
patent: 2196798 (1940-04-01), Horstmann
patent: 3620242 (1971-11-01), Pease
patent: 3698429 (1972-10-01), Lowe et al.
patent: 3794311 (1974-02-01), Rode
patent: 4208044 (1980-06-01), Schoenfeld
patent: 4325411 (1982-04-01), Squirrell
patent: 4334550 (1982-06-01), Connor et al.
patent: 4575099 (1986-03-01), Nash
patent: 4628963 (1986-12-01), Ishijima et al.
patent: 4664154 (1987-05-01), Kamata et al.
patent: 4823836 (1989-04-01), Bachmann et al.

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