Safety valves for wells

Claim 3

A device in accordance with claim 1 including a control fluid conduit connected with said device for directing control fluid pressure from a surface positioned fluid control system to said pressure responsiVe means for operating said device from the surface end of a well.

Claim 4

A device in accordance with claim 1 wherein said means for biasing said operator means in a direction to hold said valve means closed includes means defining a dome gas chamber adapted to be charged to a predetermined pressure to apply a gas pressure to said operator means and a spring engaged between said housing and said operator means for applying a force to said operator means.

Claim 5

A device in accordance with claim 3 including first chamber means provided at a first end of said dome chamber on the opposite side of said pressure responsive means from said dome chamber adapted to be sealed at a predetermined pressure lower than the pressure in said dome chamber; said pressure responsive means being exposed to the pressure in said first chamber means; second chamber means provided at the other end of said dome chamber; a slidable safety piston disposed in said second chamber means; seal means between said piston and said operator means and said housing, said piston and said second chamber means being sized to permit sealing said second end of said dome chamber by said piston at a first position of said piston and providing communication around said piston into said second end of said dome chamber at a second position of said piston; and said housing having means communicating with said second chamber means on the opposite side of said piston from said dome chamber whereby said piston is exposed to pressure for displacing said piston toward said dome chamber responsive to a predetermined pressure differential between a pressure applied exterior of and the pressure within said dome chamber.

Claim 6

A device in accordance with claim 3 including piston means on said operator means defining a first end of said dome gas chamber; means defining a first control chamber at said first end of said dome gas chamber on the opposite side of said piston means from said dome gas chamber, said first control chamber being sealed at a pressure below the pressure in said dome gas chamber; seal means between said housing and said operator means sealing an opposite second end of said dome gas chamber; means defining a second control chamber between said operator means and said housing at said second end of and separate from said dome gas chamber; a pair of coengaged first and second pistons in said second control chamber, said first piston being movable toward said second end of said dome chamber; an operating flange on said operator means within said second control chamber and engageable by said first piston for moving said operator means to close said valve responsive to movement of said first piston toward said dome gas chamber; said second piston being movable away from said dome gas chamber and being engageable with said operator means for moving said operator means in a direction to open said valve; releasable coupling means between said second piston and said operator means for releasing said operator means from said second piston to permit said operator means to move in a direction to close said valve independently of said second piston; said housing having flow passage means into said second control chamber between said first and second pistons for applying a control pressure against said second piston to bias said valve toward an open position at a pressure above a predetermined minimum and for urging said first piston in a direction away from said second piston for moving said operator means in a direction to close said valve responsive to a control pressure in excess of a predetermined maximum.

Claim 7

A device in accordance with claim 3 wherein a portion of said pressure responsive means exposed to said control fluid pressure at a first end of said dome chamber is smaller in area than another portion of said pressure responsive means exposed to the pressure in said dome chamber whereby the pressure in said dome chamber may be maintained at a minimum; chamber means defined at a second end of said dome chambEr between said operator means and said housing; said housing being provided with passage means into said chamber means; and piston means movably disposed in said chamber means for sealing said chamber means at a first position of said piston means and for communicating said second end of said dome gas chamber through said chamber means to said passage means at a second position of said piston means when said piston means is disposed to said second position by pressure applied through passage means.

Claim 8

A device in accordance with claim 6 including releasable means between said piston means and said housing for holding said piston means at said first sealing position until the pressure applied through said flow passage means exceeds a predetermined level.

Claim 9

A device in accordance with claim 6 including means defining a pressure chargeable chamber around said annular piston between a head portion and a skirt portion of said piston defined between a sealed area of said head portion and a sealed area of said skirt portion whereby the operating characteristics of said piston are varied by changes in the pressure within said chamber.

Claim 10

A device in accordance with claim 3 wherein said operator means includes a piston forming a movable closure at a first end of said dome gas chamber and the second end of said dome gas chamber is closed by seal means exposed on one side to the pressure of gas in said dome chamber; said housing is provided with passage means communicating with the other side of said seal means at said second end of said dome chamber; and at least one of said piston and said seal means includes said deactivating means for effecting closure of said valve means responsive to said second higher control pressure.

Claim 11

A device in accordance with claim 3 wherein said deactivating means comprises means responsive to a predetermined high pressure for displacing seal means to non-sealing portions on at least one of said piston and said seal means at said second end of said dome chamber for equalizing the pressures on opposite sides of said piston to permit said spring to move said operator means to close said valve when said pressure is applied to said one of said seal means.

Claim 12

A device in accordance with claim 10 including seal means between said valve operator means and said housing on the opposite side of said piston from said dome chamber and seal means between said valve operator means and said housing on the opposite side from said dome chamber of said passage means communicating with said seal means at said second end of said dome gas chamber.

Claim 13

A device in accordance with claim 9 wherein a side of said piston opposite said dome chamber and said passage means at said second end of said dome chamber are adapted to communicate directly with the tubing-casing annulus of a well when said device is in operating position in said well.

Claim 14

A device in accordance with claim 9 including conduit means connected with said device communicating with a side of said piston opposite said dome chamber and said passage means at said second end of said dome chamber for conducting control fluid under pressure from a surface system independently of the tubing-casing annulus of a well when said device is in operating position in said well.

Claim 15

A device in accordance with claim 9 including conduit means connected with said device communicating with a side of said piston opposite said dome chamber for conducting control fluid under pressure from a surface control system to said piston when said device is in operating position in said well and said passage means at said second end of said dome chamber communicates directly with the tubing-casing annulus of said well when said device is in said operating position in said well.

Claim 16

A safety valve for a well tubing string comprising: a tubular outer housing member adapted to be operatively connected with said tubing string, said housing member having a longitudinal flow passage disposed coincident with the flOw passage through said tubing string when said valve is operatively connected with said tubing string; a tubular valve operator longitudinally movably mounted in said housing member; a valve in said housing member operatively connected with said valve operator to be opened and closed responsive to longitudinal movement of said valve operator for controlling flow along said longitudinal passage of said housing member; means in said housing member biasing said valve operator longitudinally to close said valve comprising a chamber for a fixed predetermined charge of gas under pressure acting upon said valve operator; spring means between said housing member and said valve operator to move said valve operator to close said valve upon occurrence of a predetermined low pressure condition communicated to said valve housing member, said pressure condition opposing the forces of said spring and said charge of gaseous pressure; and deactivating means between said valve operator and said housing member for rendering inoperative said pressure condition opposing the forces of said spring and said charge of gaseous pressure whereby said opposing pressure condition is ineffective to bias said valve open whereby said valve is closed responsive to a predetermined high pressure condition communicated to said valve.

Claim 17

A safety valve for a well tubing string comprising: a tubular outer housing member adapted to be operatively connected with said tubing string, said housing member having a longitudinal flow passage disposed coincident with the flOw passage through said tubing string when said valve is operatively connected with said tubing string; a tubular valve operator longitudinally movably mounted in said housing member; a valve in said housing member operatively connected with said valve operator to be opened and closed responsive to longitudinal movement of said valve operator for controlling flow along said longitudinal passage of said housing member; means in said housing member biasing said valve operator longitudinally to close said valve comprising a chamber for a fixed predetermined charge of gas under pressure acting upon said valve operator; spring means between said housing member and said valve operator to move said valve operator to close said valve upon occurrence of a predetermined low pressure condition communicated to said valve housing member, said pressure condition opposing the forces of said spring and said charge of gaseous pressure; and deactivating means between said valve operator and said housing member for rendering inoperative said pressure condition opposing the forces of said spring and said charge of gaseous pressure whereby said opposing pressure condition is ineffective to bias said valve open whereby said valve is closed responsive to a predetermined high pressure condition communicated to said valve.

Claim 18

A well valve in accordance with claim 15 wherein said means for closing said valve responsive to said predetermined high pressure include a pair of telescopically coengaged annular pistons between said valve operator and said housing member, a first of said annular pistons releasably engaging said valve operator for holding said valve operator at a position at which said valve is open responsive to control pressure communicated to said valve, said first piston opposing the force of said spring means and said fixed predetermined charge of gas, and said second annular piston being engageable with said valve operator for releasing said valve operator from said first annular piston to deactivate said first piston and forcing said valve operator in a direction to close said valve independently of said spring and said charge of gas responsive to said predetermined high pressure.

Claim 19

A well valve in accordance with claim 15 wherein said deactivating means for closing said valve responsive to said predetermined high pressure comprises displaceable seal means confining said charge of gas in said chamber and adapted to be moved ina a non-sealing relation for equalizing the pressure in said chamber with the pressure communicated to said valve from exterior of said housing member to permit said spring to move said valve operator to a position to close said valve.

Claim 20

A well valve in accordance with claim 17 wherein said deactivating means for closing said valve responsive to said high predetermined pressure includes an annular piston between said valve operator and said housing member at one end of said chamber for said charge of gas, said annular piston being responsive to said pressure communicated to said valve from exterior of said tubular housing and being movable from a first sealing relationship between said housing member and said valve operator to a second non-sealing relationship between said valve operator and said housing member at which said chamber is communicated with said pressure exterior of said housing member.

Claim 21

A flow control device for a well tubing string comprising: a tubular housing adapted to be operatively connected with said tubing string and having a longitudinal flow passage disposed coincident with a flow passage through said tubing string when said housing is so associated with said tubing string; a tubular valve operator concentrically positioned within said housing for movement between a valve-open position and a valve-closed position, said valve operator having a longitudinal flow passage coincident with said flow passage through said housing; valve means within said housing movable between open and closed positions for controlling fluid floW in said housing into said valve operator; said valve operator being concentrically spaced within said housing; said valve operator and said housing having means dividing the annular space between said housing and said valve operator along the length of said operator into a first upper annular chamber, a second intermediate annular chamber, and a third lower annular chamber; a seal between said housing and an upper end portion of said valve operator sealing at a location between said upper chamber and said flow passage through said housing; said housing having a port communicating with said first upper annular chamber; said valve operator having an annular piston dividing said upper and said second intermediate annular chamber for biasing said operator downwardly responsive to a fluid pressure communicated to said first side port into said upper chamber and biasing said operator upwardly responsive to pressure in said second chamber; side port and port closure means in said housing into said second intermediate chamber for injecting gas into said chamber to pressurize said chamber to a predetermined value for biasing said valve operator upwardly; a spring between said housing and said valve operator biasing said valve operator upwardly; seal means between said housing and said valve operator at the lower end of said second chamber separating said second chamber from said third chamber; said housing being provided with a second side port communicating with said third lower annular chamber; seal means between said valve operator and said housing below said second lateral port sealing between said housing and said valve operator at a location between said longitudinal passage through said housing and said third lower annular chamber; and means between said valve operator and said housing for effecting pressure equalization across said annular piston on said valve operator for closure of said valve responsive to a predetermined high pressure around said tubular housing.

Claim 22

A flow control device for a well tubing string comprising: a tubular housing adapted to be operatively connected with said tubing string and having a longitudinal flow passage disposed coincident with a flow passage through said tubing string when said housing is so associated with said tubing string; a tubular valve operator concentrically positioned within said housing for movement between a valve-open position and a valve-closed position, said valve operator having a longitudinal flow passage coincident with said flow passage through said housing; valve means within said housing movable between open and closed positions for controlling fluid floW in said housing into said valve operator; said valve operator being concentrically spaced within said housing; said valve operator and said housing having means dividing the annular space between said housing and said valve operator along the length of said operator into a first upper annular chamber, a second intermediate annular chamber, and a third lower annular chamber; a seal between said housing and an upper end portion of said valve operator sealing at a location between said upper chamber and said flow passage through said housing; said housing having a port communicating with said first upper annular chamber; said valve operator having an annular piston dividing said upper and said second intermediate annular chamber for biasing said operator downwardly responsive to a fluid pressure communicated to said first side port into said upper chamber and biasing said operator upwardly responsive to pressure in said second chamber; side port and port closure means in said housing into said second intermediate chamber for injecting gas into said chamber to pressurize said chamber to a predetermined value for biasing said valve operator upwardly; a spring between said housing and said valve operator biasing said valve operator upwardly; seal means between said housing and said valve operator at the lower end of said second chamber separating said second chamber from said third chamber; said housing being provided with a second side port communicating with said third lower annular chamber; seal means between said valve operator and said housing below said second lateral port sealing between said housing and said valve operator at a location between said longitudinal passage through said housing and said third lower annular chamber; and means between said valve operator and said housing for effecting pressure equalization across said annular piston on said valve operator for closure of said valve responsive to a predetermined high pressure around said tubular housing.

Claim 23

A valve for controlling flow through a tubing string of a well comprising: a tubular housing having a longitudinal flow passage therethrough and adapted to be operatively associated with said tubing string, said flow passage being coincident with the flow passage along said tubing string when said housing is so associated; a tubular valve operator having a longitudinal flow passage therethrough operatively associated in concentric relationship within said housing, said flow passage of said operator being coincident with said flow passage of said housing, said operator being movable between valve-open and valve-closed positions; a valve supported in said housing and operatively connected with said valve operator for controlling flow through said flow passages of said housing and said valve operator, said valve being opened and closed by said valve operator; said valve operator in said housing being concentrically arranged to define therebetween a first upper annular chamber, a second intermediate annular chamber, and a third lower annular chamber; seal means between an upper end portion of said valve operator and said housing above said first upper annular chamber sealing between said valve operator and said housing at a location between said flow passage through said housing and said first upper annular chamber; means providing a side port and a closure member for said port in a wall portion of said housing leading to said first upper annular chamber whereby said chamber may be sealed at a pressure less than the pressure in said second intermediate annular chamber; a seal between said housing and said valve operator sealing between said housing and said valve operator between said first and second annular chambers; said housing having a lateral port leading to said second annular chamber below said seal between said first and second annular chambers; said operator having an annular piston separating said second annular chamber and said third annular chamber, said piston having a seal for sealing beTween said piston and said housing; a stop shoulder provided within said third annular chamber on said housing spaced below said operator piston; a spring confined in said third annular chamber between said stop shoulder and said annular piston on said valve operator for biasing said valve operator in a direction to close said valve; said housing having a side port and closure means leading to said third annular chamber for charging said chamber with a gas to provide a pressure therein of a predetermined value for applying a gas pressure force to said operator piston for biasing said valve operator in a direction to close said valve; an annular piston disposed in said third annular chamber below said stop shoulder therein, said piston having a head portion and a reduced skirt portion; seal means sealing between said annular piston and said valve operator and housing whereby the lower end portion of said third annular chamber is sealed at a first position of said annular piston and said seal means are moved with said piston into a larger portion of said third annular chamber at a second position of said annular piston for communicating said third annular chamber below said piston with said chamber above said piston; said housing having a lateral port communicating with said reduced portion of said third annular chamber below said annular piston for applying a pressure to said annular piston from exterior of said housing for forcing said piston upwardly to permit communication past said piston into said third annular chamber above said piston to permit said valve to close under predetermined high pressure conditions around said valve; and a seal within said housing around said valve operator below said side port into said third annular chamber for sealing between said housing and said valve operator at a location between said third annular chamber and said longitudinal flow passage through said housing, said latter seal engaging said valve operator around a line of sealing engagement with said valve operator of the same diameter as a line of sealing engagement between said seal at the upper end of said first upper annular chamber with said valve operator at the upper end thereof whereby said valve operator is non-responsive to pressure conditions through said longitudinal flow passage of said housing.

Claim 24

A valve for controlling flow through a tubing string of a well comprising: a tubular housing having a longitudinal flow passage therethrough and adapted to be operatively associated with said tubing string, said flow passage being coincident with the flow passage along said tubing string when said housing is so associated; a tubular valve operator having a longitudinal flow passage therethrough operatively associated in concentric relationship within said housing, said flow passage of said operator being coincident with said flow passage of said housing, said operator being movable between valve-open and valve-closed positions; a valve supported in said housing and operatively connected with said valve operator for controlling flow through said flow passages of said housing and said valve operator, said valve being opened and closed by said valve operator; said valve operator in said housing being concentrically arranged to define therebetween a first upper annular chamber, a second intermediate annular chamber, and a third lower annular chamber; seal means between an upper end portion of said valve operator and said housing above said first upper annular chamber sealing between said valve operator and said housing at a location between said flow passage through said housing and said first upper annular chamber; means providing a side port and a closure member for said port in a wall portion of said housing leading to said first upper annular chamber whereby said chamber may be sealed at a pressure less than the pressure in said second intermediate annular chamber; a seal between said housing and said valve operator sealing between said housing and said valve operator between said first and second annular chambers; said housing having a lateral port leading to said second annular chamber below said seal between said first and second annular chambers; said operator having an annular piston separating said second annular chamber and said third annular chamber, said piston having a seal for sealing beTween said piston and said housing; a stop shoulder provided within said third annular chamber on said housing spaced below said operator piston; a spring confined in said third annular chamber between said stop shoulder and said annular piston on said valve operator for biasing said valve operator in a direction to close said valve; said housing having a side port and closure means leading to said third annular chamber for charging said chamber with a gas to provide a pressure therein of a predetermined value for applying a gas pressure force to said operator piston for biasing said valve operator in a direction to close said valve; an annular piston disposed in said third annular chamber below said stop shoulder therein, said piston having a head portion and a reduced skirt portion; seal means sealing between said annular piston and said valve operator and housing whereby the lower end portion of said third annular chamber is sealed at a first position of said annular piston and said seal means are moved with said piston into a larger portion of said third annular chamber at a second position of said annular piston for communicating said third annular chamber below said piston with said chamber above said piston; said housing having a lateral port communicating with said reduced portion of said third annular chamber below said annular piston for applying a pressure to said annular piston from exterior of said housing for forcing said piston upwardly to permit communication past said piston into said third annular chamber above said piston to permit said valve to close under predetermined high pressure conditions around said valve; and a seal within said housing around said valve operator below said side port into said third annular chamber for sealing between said housing and said valve operator at a location between said third annular chamber and said longitudinal flow passage through said housing, said latter seal engaging said valve operator around a line of sealing engagement with said valve operator of the same diameter as a line of sealing engagement between said seal at the upper end of said first upper annular chamber with said valve operator at the upper end thereof whereby said valve operator is non-responsive to pressure conditions through said longitudinal flow passage of said housing.

Claim 25

A valve for flow control through a tubing string of a well comprising: a tubular valve housing adapted to be operatively associated with said tubing string and having a longitudinal flow passage coincident with a flow passage through said tubing string when said housing is so associated; a tubular valve operator having a longitudinal flow passage disposed for longitudinal movement within said housing; a valve operatively connected in said housing and coupled with said valve operator, said valve being opened and closed by longitudinal movement of said valve operator; said valve operator and said housing being concentrically spaced to define upper and lower annular chambers therebetween; a seal between said housing and an upper end portion of said valve operator at the upper end of said upper chamber for sealing between said valve operator and said housing at a location between said longitudinal flow passage through said housing and said upper chamber; said valve operator having an external annular operator piston dividing said upper annular chamber said said lower annular chamber; said housing having an internal stop flange along said lower annular chamber spaced from said operator piston; a spring disposed within said lower annular chamber between said operator piston and said stop flange for biasing said valve operator in a direction to close said valve; a lower portion of said lower annular chamber being incrementally reduced in radial thickness by variations in wall thickness of said valve operator and said housing along said lower portion of said lower annular chamber; an annular relief piston disposed within said lower portion of said lower annular chamber and having Seals around inner and outer wall portions of a head portion thereof for sealing with said valve housing and said valve operator to close said lower annular chamber along said lower portion thereof for defining within said chamber between said piston and said operator piston a dome chamber for containing a gas under predetermined pressure for applying a force to said operator piston to bias said valve operator in a direction to CLOSE SAID VALVE: A SIDE PORT AND CLOSURE MEANS PROVIDED IN SAID HOUSING INTO SAID LOWER ANNULAR CHAMBER ABOVE SAID annular piston for charging said dome chamber to a predetermined gas pressure, said upper annular chamber having a cross-sectional area less than the cross-sectional area of said dome chamber for reducing the value of the pressure to which said dome chamber is charged under predetermined well conditions; said annular relief piston having a lower reduced skirt portion extending into a reduced lower end portion of said lower annular chamber; seal means within said lower reduced portion of said lower annular chamber sealing within said chamber portion below a lower end of said relief piston skirt portion; said annular relief piston being movable upwardly from lower reduced portions of said lower annular chamber to a position out of sealing engagement between said valve operator and said housing to communicate past said piston into the lower end of said portion of said lower annular chamber defining said dome chamber; said housing having a side port communicating with said lower end portion of said lower annular chamber below said packing at the lower end of said relief piston skirt portion for communication with a pressure source exterior of said valve housing; and a seal between said valve operator and said housing at the lower end of said lower annular chamber below said port in said housing leading to said chamber for sealing between said valve operator and said housing at a location between the longitudinal flow passage through said housing and the lower end of said lower annular chamber, said latter seal effecting a seal between said operator and said housing around a line of sealing engagement equal to a line of sealing engagement between said operator at the upper end thereof in said housing by said seal at the upper end of said upper first annular chamber whereby said valve operator is nonresponsive to pressure conditions within said longitudinal flow passage of said housing.

Claim 26

A valve for flow control through a tubing string of a well comprising: a tubular valve housing adapted to be operatively associated with said tubing string and having a longitudinal flow passage coincident with a flow passage through said tubing string when said housing is so associated; a tubular valve operator having a longitudinal flow passage disposed for longitudinal movement within said housing; a valve operatively connected in said housing and coupled with said valve operator, said valve being opened and closed by longitudinal movement of said valve operator; said valve operator and said housing being concentrically spaced to define upper and lower annular chambers therebetween; a seal between said housing and an upper end portion of said valve operator at the upper end of said upper chamber for sealing between said valve operator and said housing at a location between said longitudinal flow passage through said housing and said upper chamber; said valve operator having an external annular operator piston dividing said upper annular chamber said said lower annular chamber; said housing having an internal stop flange along said lower annular chamber spaced from said operator piston; a spring disposed within said lower annular chamber between said operator piston and said stop flange for biasing said valve operator in a direction to close said valve; a lower portion of said lower annular chamber being incrementally reduced in radial thickness by variations in wall thickness of said valve operator and said housing along said lower portion of said lower annular chamber; an annular relief piston disposed within said lower portion of said lower annular chamber and having Seals around inner and outer wall portions of a head portion thereof for sealing with said valve housing and said valve operator to close said lower annular chamber along said lower portion thereof for defining within said chamber between said piston and said operator piston a dome chamber for containing a gas under predetermined pressure for applying a force to said operator piston to bias said valve operator in a direction to CLOSE SAID VALVE: A SIDE PORT AND CLOSURE MEANS PROVIDED IN SAID HOUSING INTO SAID LOWER ANNULAR CHAMBER ABOVE SAID annular piston for charging said dome chamber to a predetermined gas pressure, said upper annular chamber having a cross-sectional area less than the cross-sectional area of said dome chamber for reducing the value of the pressure to which said dome chamber is charged under predetermined well conditions; said annular relief piston having a lower reduced skirt portion extending into a reduced lower end portion of said lower annular chamber; seal means within said lower reduced portion of said lower annular chamber sealing within said chamber portion below a lower end of said relief piston skirt portion; said annular relief piston being movable upwardly from lower reduced portions of said lower annular chamber to a position out of sealing engagement between said valve operator and said housing to communicate past said piston into the lower end of said portion of said lower annular chamber defining said dome chamber; said housing having a side port communicating with said lower end portion of said lower annular chamber below said packing at the lower end of said relief piston skirt portion for communication with a pressure source exterior of said valve housing; and a seal between said valve operator and said housing at the lower end of said lower annular chamber below said port in said housing leading to said chamber for sealing between said valve operator and said housing at a location between the longitudinal flow passage through said housing and the lower end of said lower annular chamber, said latter seal effecting a seal between said operator and said housing around a line of sealing engagement equal to a line of sealing engagement between said operator at the upper end thereof in said housing by said seal at the upper end of said upper first annular chamber whereby said valve operator is nonresponsive to pressure conditions within said longitudinal flow passage of said housing.

Claim 27

A well flow control valve in accordance with claim 21 wherein said valve operator and said valve housing are shaped along a portion of the lower end portion of said lower annular chamber at a first lower position of said annular piston to provide annular space between the piston head of said relief piston and the sealed lower reduced skirt portion of said piston, which space is sealed during assembly of said valve at a pressure below the pressure in said dome chamber during normal operation of said valve, and side port and shear pin means disposed laterally through said valve housing into said reduced skirt portion of said relief piston for sealing said lower portion of said lower annular chamber along said reduced piston skirt portion at a desired pressure and said shear pin being adapted to hold said piston against upward movement until a predetermined pressure is applied through said side port below said skirt portion.

Claim 28

A valve for controlling fluid flow through a tubing string of a well comprising: a tubular housing adapted to be operatively associated with said tubing string and having a longitudinal flow passage coincident with the flow passage through said tubing string when so associated; a tubular valve operator concentrically disposed within said valve housing and having a longitudinal flow passage coincident with said flow passage of said housing and longitudinally movable for opening and closing said valve; a valve within said housing coupled with said valve operator and adapted to be opened and closed responsive to longitudinal movemEnt of said valve operator; said valve operator being concentrically spaced within said housing and said housing and said valve operator being shaped to define upper, intermediate, and lower annular chambers between said operator and said housing; a seal between said valve operator along an upper end thereof and said housing at the upper end of said first upper annular chamber for sealing between said housing and said operator at a location between said first chamber and said flow passage through said housing; a side port and closure means in said housing opening to said first annular chamber for sealing said chamber at a desired pressure; said operator having an annular operator piston thereon and having seal means therein for sealing between said piston and said housing separating said first annular chamber and said second annular chamber, said second annular chamber comprising a dome chamber adapted to be pressurized to a predetermined level for providing a gas pressure within said dome chamber for applying a force to said operator piston for biasing said valve operator in a direction to close said valve; said housing having an internal flange and seal means thereon between said valve operator and said housing defining a lower end of said dome chamber; a spring within said dome chamber confined between said operator piston and said internal flange of said housing for biasing said valve operator in a direction to close said valve; said port means having closure means in said housing opening into said dome chamber to permit said chamber to be pressured with a gaseous medium to a desired level; said housing having an internal flange and seal means engaging said valve operator defining a lower end of said lower annular chamber between said valve operator and said housing; a pair of telescopically related annular pistons slidably disposed in said lower annular chamber, each of said pistons having a had portion and reduced skirt portion, the skirt portions of said pistons being intermeshed in telescopic relationship; said housing having a side port opening into said lower annular chamber between said annular pistons, whereby said annular pistons are urged in opposite directions responsive to pressure communicated into said chamber through said side port; said valve operator having an external annular operating flange disposed in said lower annular chamber above said upper annular piston whereby upward movement of said upper piston lifts said valve operator to close said valve; shear means releasably securing said upper piston with said valve housing at a first lower position at which said valve operator is permitted to move longitudinally between upper and lower end positions; shearable means releasably coupling said lower piston with said valve operator whereby said lower piston is adapted to hold said valve operator at a lower end position for holding said valve open responsive to a pressure applied from exterior of said housing through side port into said lower annular chamber between said annular pistons when said pressure is of a value sufficient to overcome the pressure in said dome chamber and the force of said spring against said annular operator piston; an internal annular flange in said housing defining a lower end of said lower annular chamber and providing a lower stop shoulder for said lower annular piston positioning said piston at a lower end position for holding said valve operator at a position at which said valve is open; and a seal in said flange at the lower end of said lower annular chamber sealing between said flange and said valve operator for sealing between said housing and said valve operator at a location between said longitudinal flow passage through said housing and a lower end of said lower annular chamber, said seals in said lower housing flange and at the end of said upper annular chamber sealing along lines of engagement with said valve operator of equal diameter whereby said valve operator is non-responsive to pressure conditions in said lOngitudinal flow passage through said housing.

Claim 29

A valve for controlling fluid flow through a tubing string of a well comprising: a tubular housing adapted to be operatively associated with said tubing string and having a longitudinal flow passage coincident with the flow passage through said tubing string when so associated; a tubular valve operator concentrically disposed within said valve housing and having a longitudinal flow passage coincident with said flow passage of said housing and longitudinally movable for opening and closing said valve; a valve within said housing coupled with said valve operator and adapted to be opened and closed responsive to longitudinal movemEnt of said valve operator; said valve operator being concentrically spaced within said housing and said housing and said valve operator being shaped to define upper, intermediate, and lower annular chambers between said operator and said housing; a seal between said valve operator along an upper end thereof and said housing at the upper end of said first upper annular chamber for sealing between said housing and said operator at a location between said first chamber and said flow passage through said housing; a side port and closure means in said housing opening to said first annular chamber for sealing said chamber at a desired pressure; said operator having an annular operator piston thereon and having seal means therein for sealing between said piston and said housing separating said first annular chamber and said second annular chamber, said second annular chamber comprising a dome chamber adapted to be pressurized to a predetermined level for providing a gas pressure within said dome chamber for applying a force to said operator piston for biasing said valve operator in a direction to close said valve; said housing having an internal flange and seal means thereon between said valve operator and said housing defining a lower end of said dome chamber; a spring within said dome chamber confined between said operator piston and said internal flange of said housing for biasing said valve operator in a direction to close said valve; said port means having closure means in said housing opening into said dome chamber to permit said chamber to be pressured with a gaseous medium to a desired level; said housing having an internal flange and seal means engaging said valve operator defining a lower end of said lower annular chamber between said valve operator and said housing; a pair of telescopically related annular pistons slidably disposed in said lower annular chamber, each of said pistons having a had portion and reduced skirt portion, the skirt portions of said pistons being intermeshed in telescopic relationship; said housing having a side port opening into said lower annular chamber between said annular pistons, whereby said annular pistons are urged in opposite directions responsive to pressure communicated into said chamber through said side port; said valve operator having an external annular operating flange disposed in said lower annular chamber above said upper annular piston whereby upward movement of said upper piston lifts said valve operator to close said valve; shear means releasably securing said upper piston with said valve housing at a first lower position at which said valve operator is permitted to move longitudinally between upper and lower end positions; shearable means releasably coupling said lower piston with said valve operator whereby said lower piston is adapted to hold said valve operator at a lower end position for holding said valve open responsive to a pressure applied from exterior of said housing through side port into said lower annular chamber between said annular pistons when said pressure is of a value sufficient to overcome the pressure in said dome chamber and the force of said spring against said annular operator piston; an internal annular flange in said housing defining a lower end of said lower annular chamber and providing a lower stop shoulder for said lower annular piston positioning said piston at a lower end position for holding said valve operator at a position at which said valve is open; and a seal in said flange at the lower end of said lower annular chamber sealing between said flange and said valve operator for sealing between said housing and said valve operator at a location between said longitudinal flow passage through said housing and a lower end of said lower annular chamber, said seals in said lower housing flange and at the end of said upper annular chamber sealing along lines of engagement with said valve operator of equal diameter whereby said valve operator is non-responsive to pressure conditions in said lOngitudinal flow passage through said housing.

Claim 32

A device as set forth in claim 24, wherein: the means for conducting pressure to said pressure-responsive actuating means is at least one lateral port extending through the wall of the valve housing.

Claim 35

A device as set forth in claim 26, wherein: said confining means is at least one sealing means rendered inoperative responsive to said control pressure above a predetermined value and positioned with respect to the pressure-responsive actuating means to effect an equalization of pressure across the actuating means when said sealing means is rendered inoperative.