Flow control apparatus and method with leak detection

Claim 2

In apparatus having pressure sealing and leak detection means, a sleeve having an inner cylindrical surface and a converging entrant portion at at least one end of the sleeve, means forming liquid enclosing spaces communicating with the ends of the sleeve, a plunger or barrier, means serving to carry the plunger for movements axially of the sleeve, and means for moving the plunger between a retracted position out of the sleeve and a projected position within the sleeve, said plunger comprising two oppositely faced cup-shaped sealing members made of resilient material, each of the sealing members having a rim conforming to a truncated cone when relaxed and having an annular surface at the edge margin of the rim adapted to engage and seal with respect to the inner surface of the sleeve, the diameters of said annular surfaces being substantially greater than the inner diameter of the sleeve when the members are relaxed, the rims of said members being contracted and stressed by flexing when projected into the sleeve, said rims as viewed in section when within the sleeve being at an acute angle to the inner cylindrical surface of the sleeve whereby forces tending to expand the rims serve to urge the edge margins against the sleeve.

Claim 3

Apparatus as in claim 1 in which the space between the sealing members is closed when the plunger is moved to said projected position, the contraction of the rim of one of the sealing members during such movement causing a drop in pressure in the last named space.

Claim 4

Apparatus as in claim 1 in which the liquid enclosing space occupied by the plunger in its retracted position is dimensioned to permit relaxation of the sealing members.

Claim 5

Apparatus as in claim 1 in which there is a convergent entrant portion at each end of the sleeve and the spaces communicating with the ends of the sleeve are dimensioned to permit radial expansion of the rims of the sealing members when the plunger is moved into either one of said spaces.

Claim 6

Apparatus as in claim 1 in which the edge margins of the rims are beveled to facilitate contraction when moved into the sleeve through an entrant portion.

Claim 7

In apparatus having pressure sealing and leak detection means, a sleeve having an inner cylindrical surface and a converging entrant portion at at least one end of the sleeve, means forming liquid enclosing spaces communicating with the ends of the sleeve, a plunger or barrier, means serving to carry the plunger for movements axially of the sleeve, and means for moving the plunger between a retracted position out of the sleeve and a projected position within the sleeve, said plunger comprising two oppositely faced cup-shaped sealing members made of resilient material, each of the sealing members having a rim conforming to a truncated cone when relaxed and having one annular surface near the edge of the rim adapted to engage and seal with respect to the inner surface of the sleeve, the diameters of said annular surfaces being substantially greater than the inner diameter of the sleeve when the members arE relaxed, the rims of said members being contracted and stressed by flexing when projected into the sleeve whereby when the plunger is in its projected position the static pressure in the space between these sealing members is reduced to a level substantially less than the static pressure in the one space from which the plunger was projected, thereby providing a pressure differential between said one space and the space between the sealing members, and leak detection means exterior of the sleeve having a fluid connection with said space between the sealing members and also a fluid connection with one of said enclosing spaces, said leak detection means serving to indicate the presence of said pressure differential and also the reduction of such pressure differential below a predetermined amount.

Claim 8

In apparatus having pressure sealing and leak detection means, a sleeve having an inner cylindrical surface and a converging entrant portion at at least one end of the sleeve, means forming liquid enclosing spaces communicating with the ends of the sleeve, a plunger or barrier, means serving to carry the plunger for movements axially of the sleeve, and means for moving the plunger between a retracted position out of the sleeve and a projected position within the sleeve, said plunger comprising two oppositely faced cup-shaped sealing members made of resilient material, each of the sealing members having a rim conforming to a truncated cone when relaxed and having one annular surface near the edge of the rim adapted to engage and seal with respect to the inner surface of the sleeve, the diameters of said annular surfaces being substantially greater than the inner diameter of the sleeve when the members arE relaxed, the rims of said members being contracted and stressed by flexing when projected into the sleeve whereby when the plunger is in its projected position the static pressure in the space between these sealing members is reduced to a level substantially less than the static pressure in the one space from which the plunger was projected, thereby providing a pressure differential between said one space and the space between the sealing members, and leak detection means exterior of the sleeve having a fluid connection with said space between the sealing members and also a fluid connection with one of said enclosing spaces, said leak detection means serving to indicate the presence of said pressure differential and also the reduction of such pressure differential below a predetermined amount.

Claim 9

Apparatus as in claim 6 in which said leak detection means includes a differential pressure operated switch of the type having closed fluid chambers and a fluid pressure operated member separating the chambers, one of said chambers having a fluid connection with the closed space between the sealing members when the plunger is in its projected position, the other one of said chambers having fluid connection with one of said liquid enclosing spaces whereby said switch is operated in response to pressure differential, electrical circuitry connected to the contacts of said switch, and indicating means included in said circuitry for indicating the presence of a pressure differential greater than a predetermined amount or less than such amount.

Claim 10

In a method for detecting liquid leakage past a plunger which is adapted to be projected into and out of a cylindrical sleeve which connects spaces containing liquid under pressure, the plunger comprising cup-shaped sealing members made of resilient material and oppositely faced, the steps of moving the plunger from a retracted position in one of said spaces to a projected position within the sleeve with contraction and flexing of the rims of the sealing members as they are projected into the sleeve and with drop in pressure in the space between the sealing members to a value substantially less than the static pressure in one of said spaces, and then detecting any leakage past the sealing members by noting any drop in said pressure differential.

Claim 11

In a method for detecting liquid leakage past a plunger which is adapted to be projected into and out of a cylindrical sleeve which connects spaces containing liquid under pressure, the plunger comprising cup-shaped sealing members made of resilient material and oppositely faced, the steps of moving the plunger from a retracted position in one of said spaces to a projected position within the sleeve with contraction and flexing of the rims of the sealing members as they are projected into the sleeve and with drop in pressure in the space between the sealing members to a value substantially less than the static pressure in one of said spaces, and then detecting any leakage past the sealing members by noting any drop in said pressure differential.