Annular blowout preventer

Claim 2

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said other annulus having a lower modulus of elasticity than that of the resilient material of the packer annulus, said housing having a cylinder means therein and guideway means connecting the cylinder means with the recess, piston means longitudinally reciprocable within the cylinder means, means for selectively admitting and exhausting operating fluid to and from the cylinder means on opposite sides of the piston means so as to reciprocate the piston means, a ring having a surface engageable with and substantially radially coextensive with one end of the outer annulus, and means extending sealably through the guideway means and connecting the ring to the piston means, whereby upon movement of the piston means in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer from expanded to constricted position, and upon movement of the piston means in the opposite direction, said ring relieves the compression in said outer annulus to permit its inner circumference to expand and thereby permit said packer to move from constricted to expanded position.

Claim 3

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, having upper and lower sides and an annular space which extends lower than the lower side, a packer comprising an annulus of resilient material mounted in the recess for sliding movement along the upper and lower sides thereof between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having a cylinder means therein and guideway means connecting the cylinder means with the recess, piston means longitudinally reciprocable within the cylinder means, means for selectively admitting and exhausting operating fluid to and from the cylinder means on opposite sides of the piston means so as to reciprocate the piston means, a ring beneath the outer annulus having a surface engageable with and substantially radially coextensive with the lower end of the outer annulus, and means extending sealably through the guideway means and connecting the ring to the piston means, whereby upon movement of the piston means in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference to thereby move said packer from expanded to constricted position, and upon movement of the piston means in the opposite direction, said ring relieves the compression in said outer annulus to permit its inner circumference to expand and thereby permit said packer to move from constricted to expanded position, the lower ends of said ring and outer annulus being disposed within said annular space of the recess when said packer is in expanded position, so that, upon upward movement of the ring, the outer annulus remains in contact with the entire outer circumference of the packer.

Claim 4

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, having upper and lower sides and an annular space which extends lower than the lower side, a packer comprising an annulus of resilient material mounted in the recess for sliding movement along the upper and lower sides thereof between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having a cylinder means therein and guideway means connecting the cylinder means with the recess, piston means longitudinally reciprocable within the cylinder means, means for selectively admitting and exhausting operating fluid to and from the cylinder means on opposite sides of the piston means so as to reciprocate the piston means, a ring beneath the outer annulus having a surface engageable with and substantially radially coextensive with the lower end of the outer annulus, and means extending sealably through the guideway means and connecting the ring to the piston means, whereby upon movement of the piston means in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference to thereby move said packer from expanded to constricted position, and upon movement of the piston means in the opposite direction, said ring relieves the compression in said outer annulus to permit its inner circumference to expand and thereby permit said packer to move from constricted to expanded position, the lower ends of said ring and outer annulus being disposed within said annular space of the recess when said packer is in expanded position, so that, upon upward movement of the ring, the outer annulus remains in contact with the entire outer circumference of the packer.

Claim 5

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having a cylinder means therein and guideway means connecting the cylinder means with the recess, piston means longitudinally reciprocable within the cylinder means, means for selectively admitting and exhausting operating fluid to and from the cylinder means on opposite sides of the piston so as to reciprocate the piston means, a ring having a conically shaped surface engageable with and substantially radially coextensive with a conically shaped end of the outer annulus, and means extending sealably through the guideway means and connecting the ring to the piston means, whereby upon movement of the piston means in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer from expanded to constricted position, and upon movement of the piston means in the opposite direction, said ring relieves the compression in said outer annulus to permit its inner circumference to expand and thereby permit said packer to move from constricted to expanded position.

Claim 6

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having a cylinder means therein and guideway means connecting the cylinder means with the recess, piston means longitudinally reciprocable within the cylinder means, means for selectively admitting and exhausting operating fluid to and from the cylinder means on opposite sides of the piston so as to reciprocate the piston means, a ring having a conically shaped surface engageable with and substantially radially coextensive with a conically shaped end of the outer annulus, and means extending sealably through the guideway means and connecting the ring to the piston means, whereby upon movement of the piston means in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer from expanded to constricted position, and upon movement of the piston means in the opposite direction, said ring relieves the compression in said outer annulus to permit its inner circumference to expand and thereby permit said packer to move from constricted to expanded position.

Claim 7

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having an annular cylinder therein and an annular guideway connecting the cylinder with the recess adjacent the outer circumference of the outer annulus, an annular piston longitudinally reciprocable within the cylinder, means for selectively admitting and exhausting operating fluid from and to the cylinder on opposite sides of the piston so as to reciprocate the piston therein, a sleeve connected to the piston and extending through the guideway to surround the outer annulus within the recess, annular seal means carried by the housing at the inner and outer circumferences of the annular guideway and arranged to seal with the sleeve on substantially the same horizontal level, a ring extending radially inwardly from the sleeve and having a surface engageable with and substantially coextensive with one end of the outer annulus, whereby upon movement of the piston in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer to constricted position, and upon movement of the piston in the opposite direction, said ring relieves the compression in said outer annulus so as to permit its inner circumference to expand and thereby permit said packer to move from constricted to retracted position.

Claim 8

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having an annular cylinder therein and an annular guideway connecting the cylinder with the recess adjacent the outer circumference of the outer annulus, an annular piston longitudinally reciprocable within the cylinder, means for selectively admitting and exhausting operating fluid from and to the cylinder on opposite sides of the piston so as to reciprocate the piston therein, a sleeve connected to the piston and extending through the guideway to surround the outer annulus within the recess, annular seal means carried by the housing at the inner and outer circumferences of the annular guideway and arranged to seal with the sleeve on substantially the same horizontal level, a ring extending radially inwardly from the sleeve and having a surface engageable with and substantially coextensive with one end of the outer annulus, whereby upon movement of the piston in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer to constricted position, and upon movement of the piston in the opposite direction, said ring relieves the compression in said outer annulus so as to permit its inner circumference to expand and thereby permit said packer to move from constricted to retracted position.

Claim 9

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, the resilient material of the outer annulus having a lower modulus of elasticity than that of the resilient material of the packer annulus, said housing having an annular cylinder therein and an annular guideway connecting the cylinder with the recess adjacent the outer circumference of the outer annulus, an annular piston longitudinally reciprocable within the cylinder, means for selectively admitting and exhausting operating fluid from and to the cylinder on opposite sides of the piston so as to reciprocate the piston therein, a sleeve connected to the piston and extending sealably through the guideway to surround the outer annulus within the recess, a ring extending radially inwardly from the sleeve and having a surface engageable with and substantially coextensive with one end of the outer annulus, whereby upon movement of the piston in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer to constricted position, and upon moement of the piston in the opposite direction, said ring relieves the compression in said outer annulus so as to permit its inner circumference to expand and thereby permit said packer to move from constricted to retracted position.

Claim 10

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, the resilient material of the outer annulus having a lower modulus of elasticity than that of the resilient material of the packer annulus, said housing having an annular cylinder therein and an annular guideway connecting the cylinder with the recess adjacent the outer circumference of the outer annulus, an annular piston longitudinally reciprocable within the cylinder, means for selectively admitting and exhausting operating fluid from and to the cylinder on opposite sides of the piston so as to reciprocate the piston therein, a sleeve connected to the piston and extending sealably through the guideway to surround the outer annulus within the recess, a ring extending radially inwardly from the sleeve and having a surface engageable with and substantially coextensive with one end of the outer annulus, whereby upon movement of the piston in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer to constricted position, and upon moement of the piston in the opposite direction, said ring relieves the compression in said outer annulus so as to permit its inner circumference to expand and thereby permit said packer to move from constricted to retracted position.

Claim 11

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having an annular cylinder therein and an annular guideway connecting the cylinder with the recess adjacent the outer circumference of the outer annulus, an annular piston longitudinally reciprocable within the cylinder, means for selectively admitting and exhausting operating fluid from and to the cylinder on opposite sides of the piston so as to reciprocate the piston therein, a sleeve connected to the piston and extending sealably through the guideway to surround the outer annulus within the recess, a ring extending radially inwardly from the sleeve and having a conically shaped surface engageable with and substantially coextensive with a conically shaped end of the outer annulus, whereby upon movement of the piston in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer to constricted position, and upon movement of the piston in the opposite direction, said ring relieves the compression in said outer annulus so as to permit its inner circumference to expand and thereby permit said packer to move from constricted to retracted position.

Claim 12

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having an annular cylinder therein and an annular guideway connecting the cylinder with the recess adjacent the outer circumference of the outer annulus, an annular piston longitudinally reciprocable within the cylinder, means for selectively admitting and exhausting operating fluid from and to the cylinder on opposite sides of the piston so as to reciprocate the piston therein, a sleeve connected to the piston and extending sealably through the guideway to surround the outer annulus within the recess, a ring extending radially inwardly from the sleeve and having a conically shaped surface engageable with and substantially coextensive with a conically shaped end of the outer annulus, whereby upon movement of the piston in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer to constricted position, and upon movement of the piston in the opposite direction, said ring relieves the compression in said outer annulus so as to permit its inner circumference to expand and thereby permit said packer to move from constricted to retracted position.

Claim 13

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, having upper and lower sides and an annular space which extends lower than the lower side, a packer comprising an annulus of resilient material mounted in the recess for sliding movement along the upper and lower sides thereof between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having an annular cylinder therein and an annular guideway connecting the cylinder with the recess adjacent the outer circumference of the outer annulus, an annular piston longitudinally reciprocable within the cylinder, means for selectively admitting and exhausting operating fluid from and to the cylinder on opposite sides of the piston so as to reciprocate the piston therein, a sleeve connected to the piston and extending sealably through the guideway to surround the outer annulus within the recess, a ring beneath the outer annulus extending radially inwardly from the sleeve and having a surface engageable with and substantially coextensive with the lower end of the outer annulus, whereby upon movement of the piston in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer to constricted position, and upon movement of the piston in the opposite direction, said ring relieves the compression in said outer annulus so as to permit its inner circumference to expand and thereby permit said packer to move from constricted to retracted position, the lower ends of said ring and outer annulus being disposed within said annular space when said packer is in expanded position, so that, upon upward movement of the ring, the outer annulus remains in contact with the entire outer circumference of the packer.

Claim 14

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, having upper and lower sides and an annular space which extends lower than the lower side, a packer comprising an annulus of resilient material mounted in the recess for sliding movement along the upper and lower sides thereof between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having an annular cylinder therein and an annular guideway connecting the cylinder with the recess adjacent the outer circumference of the outer annulus, an annular piston longitudinally reciprocable within the cylinder, means for selectively admitting and exhausting operating fluid from and to the cylinder on opposite sides of the piston so as to reciprocate the piston therein, a sleeve connected to the piston and extending sealably through the guideway to surround the outer annulus within the recess, a ring beneath the outer annulus extending radially inwardly from the sleeve and having a surface engageable with and substantially coextensive with the lower end of the outer annulus, whereby upon movement of the piston in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer to constricted position, and upon movement of the piston in the opposite direction, said ring relieves the compression in said outer annulus so as to permit its inner circumference to expand and thereby permit said packer to move from constricted to retracted position, the lower ends of said ring and outer annulus being disposed within said annular space when said packer is in expanded position, so that, upon upward movement of the ring, the outer annulus remains in contact with the entire outer circumference of the packer.

Claim 15

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer with the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having a cylinder means therein and guideway means connecting the cylinder means with the recess, piston means longitudinally reciprocable within the cylinder means, means for selectively admitting and exhausting operating fluid to and from the cylinder means on opposite sides of the piston means so as to reciprocate the piston means, a ring having a surface engageable with and substantially radially coextensive with one end of the outer annulus, means extending sealably through the guideway means and connecting the ring to the piston means, whereby upon movement of the piston means in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer from expanded to constricted position, and upon movement of the piston means in the opposite direction, said ring relieves the compression in said outer annulus to permit its inner circumference to expand and thereby permit said packer to move from constricted to expanded position, and means fluidly communicating the housing bore beneath the packer with said recess on the opposite surface of said ring, whereby a force due to the pressure of well fluid acting upon said outer annulus assists the force due to said operating fluid in moving the packer to and maintaining the packer in constricted position.

Claim 16

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer with the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having a cylinder means therein and guideway means connecting the cylinder means with the recess, piston means longitudinally reciprocable within the cylinder means, means for selectively admitting and exhausting operating fluid to and from the cylinder means on opposite sides of the piston means so as to reciprocate the piston means, a ring having a surface engageable with and substantially radially coextensive with one end of the outer annulus, means extending sealably through the guideway means and connecting the ring to the piston means, whereby upon movement of the piston means in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer from expanded to constricted position, and upon movement of the piston means in the opposite direction, said ring relieves the compression in said outer annulus to permit its inner circumference to expand and thereby permit said packer to move from constricted to expanded position, and means fluidly communicating the housing bore beneath the packer with said recess on the opposite surface of said ring, whereby a force due to the pressure of well fluid acting upon said outer annulus assists the force due to said operating fluid in moving the packer to and maintaining the packer in constricted position.

Claim 17

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having a cylinder means therein and guideway means concerning the cylinder means with the recess, piston means longitudinally reciprocable within the cylinder means, means for selectively admitting and exhausting operating fluid to and from the cylinder means on opposite sides of the piston means so as to reciprocate the piston means, a ring arranged lower than the piston means and having a surface engageable with and substantially radially coextensive with one end of the outer annulus, and means extending sealably through the guideway means and connecting the ring to the piston means, whereby upon movement of the piston means in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer from expanded to constricted position, and upon movement of the piston means in the opposite direcion, said ring relieves the compression in said outer annulus to permit its inner circumference to expand and thereby permit said packer to move from constricted to expanded position.

Claim 18

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having a cylinder means therein and guideway means concerning the cylinder means with the recess, piston means longitudinally reciprocable within the cylinder means, means for selectively admitting and exhausting operating fluid to and from the cylinder means on opposite sides of the piston means so as to reciprocate the piston means, a ring arranged lower than the piston means and having a surface engageable with and substantially radially coextensive with one end of the outer annulus, and means extending sealably through the guideway means and connecting the ring to the piston means, whereby upon movement of the piston means in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer from expanded to constricted position, and upon movement of the piston means in the opposite direcion, said ring relieves the compression in said outer annulus to permit its inner circumference to expand and thereby permit said packer to move from constricted to expanded position.

Claim 19

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the annulus, said housing having a cylinder means therein and guideway connecting the cylinder means with the recess, piston means longitudinally reciprocable within the cylinder means, means for selectively admitting and exhausting operating fluid to and from the cylinder means on opposite sides of the piston means so as to reciprocate the piston means, a ring having an upper surface engageable with and substantially radially coextensive with the lower end of the outer annulus, and means extending sealably through the guideway means and connecting the ring to the piston means, whereby upon movement of the piston means in one direction, the upper surface of the ring moves upwardly against the lower end of the outer annulus to longitudinally compress said outer annulus so as to constrict its inner circumference and thereby move said packer from expanded to constricted position, and upon movement of the piston means in the opposite direction, said ring relieves the compression in said outer annulus to permit its inner circumference to expand and thereby permit said packer to move from constricted to expanded position.

Claim 20

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the annulus, said housing having a cylinder means therein and guideway connecting the cylinder means with the recess, piston means longitudinally reciprocable within the cylinder means, means for selectively admitting and exhausting operating fluid to and from the cylinder means on opposite sides of the piston means so as to reciprocate the piston means, a ring having an upper surface engageable with and substantially radially coextensive with the lower end of the outer annulus, and means extending sealably through the guideway means and connecting the ring to the piston means, whereby upon movement of the piston means in one direction, the upper surface of the ring moves upwardly against the lower end of the outer annulus to longitudinally compress said outer annulus so as to constrict its inner circumference and thereby move said packer from expanded to constricted position, and upon movement of the piston means in the opposite direction, said ring relieves the compression in said outer annulus to permit its inner circumference to expand and thereby permit said packer to move from constricted to expanded position.

Claim 21

An annular blowout preventer of the character defined in claim 10, wherein the piston means is higher than the ring so as to lift the ring to compress the outer annulus.

Claim 22

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having an annular cylinder therein and an annular guideway connecting the cylinder with the recess adjacent the outer circumference of the outer annulus, an annular piston longitudinally reciprocable within the cylinder, means for selectively admitting and exhausting operating fluid from and to the cylinder on opposite sides of the piston so as to reciprocate the piston therein, a sleeve connected to the piston and extending sealably through the guideway to surround the outer annulus within the recess, a ring extending radially inwardly from the sleeve and having a surface engageable with and substantially coextensive with one end of the outer annulus, whereby upon movement of the piston in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer to constricted position, and upon movement of the piston in the opposite direction, said ring relieves the compression in said outer annulus so as to permit its inner circumference to expand and thereby permit said packer to move from constricted to retracted position, and means fluidly communicating the housing bore beneath the packer with said recess on the opposite surface of said ring, whereby a force due to the well fluid acting upon said outer annulus assist the force due to said operating fluid in moving the packer to and maintaining the packer in constricted position.

Claim 23

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having an annular cylinder therein and an annular guideway connecting the cylinder with the recess adjacent the outer circumference of the outer annulus, an annular piston longitudinally reciprocable within the cylinder, means for selectively admitting and exhausting operating fluid from and to the cylinder on opposite sides of the piston so as to reciprocate the piston therein, a sleeve connected to the piston and extending sealably through the guideway to surround the outer annulus within the recess, a ring extending radially inwardly from the sleeve and having a surface engageable with and substantially coextensive with one end of the outer annulus, whereby upon movement of the piston in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer to constricted position, and upon movement of the piston in the opposite direction, said ring relieves the compression in said outer annulus so as to permit its inner circumference to expand and thereby permit said packer to move from constricted to retracted position, and means fluidly communicating the housing bore beneath the packer with said recess on the opposite surface of said ring, whereby a force due to the well fluid acting upon said outer annulus assist the force due to said operating fluid in moving the packer to and maintaining the packer in constricted position.

Claim 24

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having an annular cylinder therein and an annular guideway connecting the cylinder with the recess adjacent the outer circumference of the outer annulus, an annular piston longitudinally reciprocable within the cylinder, means for selectively admitting and exhausting operating fluid from and to the cylinder on opposite sides of the piston so as to reciprocate the piston therein, a sleeve connected to the piston and extending sealably through the guideway to surround the outer annulus within the recess, a ring arranged lower than the piston and extending radially inwardly from the sleeve and having a surface engageable with and substantially coextensive with one end of the outer annulus, whereby upon movement of the piston in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer to constricted position, and upon movement of the piston in the opposite direction, said ring relieves the compression in said outer annulus so as to permit its inner circumference to expand and thereby permit said packer to move from constricted to retracted position.

Claim 25

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having an annular cylinder therein and an annular guideway connecting the cylinder with the recess adjacent the outer circumference of the outer annulus, an annular piston longitudinally reciprocable within the cylinder, means for selectively admitting and exhausting operating fluid from and to the cylinder on opposite sides of the piston so as to reciprocate the piston therein, a sleeve connected to the piston and extending sealably through the guideway to surround the outer annulus within the recess, a ring arranged lower than the piston and extending radially inwardly from the sleeve and having a surface engageable with and substantially coextensive with one end of the outer annulus, whereby upon movement of the piston in one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer to constricted position, and upon movement of the piston in the opposite direction, said ring relieves the compression in said outer annulus so as to permit its inner circumference to expand and thereby permit said packer to move from constricted to retracted position.

Claim 26

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having an annular cylinder therein and an annular guideway connecting the cylinder with the recess adjacent the outer circumference of the outer annulus, an annular piston longitudinally reciprocable within the cylinder, means for selectively admitting and exhausting operating fluid from and to the cylinder on opposite sides of the piston so as to reciprocate the piston therein, a sleeve connected to the piston and extending sealably through the guideway to surround the outer annulus within the recess, a ring extending radially inwardly from the sleeve and having an upper surface engageable with and substantially coextensive with the lower end of the outer annulus, whereby upon movement of the piston in one direction, the upper surface of the ring moves upwardly against the lower end of the outer annulus to longitudinally compress said outer annulus so as to constrict its inner circumference and thereby move said packer to constricted position, and upon movement of the piston in the opposite direction, said ring relieves the compression in said outer annulus so as to permit its inner circumference to expand and thereby permit said packer to move from constricted to retracted position.

Claim 27

An annular blowout preventer, comprising a housing having a bore extending longitudinally therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having an annular cylinder therein and an annular guideway connecting the cylinder with the recess adjacent the outer circumference of the outer annulus, an annular piston longitudinally reciprocable within the cylinder, means for selectively admitting and exhausting operating fluid from and to the cylinder on opposite sides of the piston so as to reciprocate the piston therein, a sleeve connected to the piston and extending sealably through the guideway to surround the outer annulus within the recess, a ring extending radially inwardly from the sleeve and having an upper surface engageable with and substantially coextensive with the lower end of the outer annulus, whereby upon movement of the piston in one direction, the upper surface of the ring moves upwardly against the lower end of the outer annulus to longitudinally compress said outer annulus so as to constrict its inner circumference and thereby move said packer to constricted position, and upon movement of the piston in the opposite direction, said ring relieves the compression in said outer annulus so as to permit its inner circumference to expand and thereby permit said packer to move from constricted to retracted position.

Claim 28

An annular blowout preventer of the character defined in claim 14, wherein the piston is higher than the ring so as to lift the ring to compress the outer annulus.

Claim 29

An annular blowout preventer, comprising a housing having a bore extending vertically therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having a cylinder means therein and guideway means connecting the cylinder means with the recess, piston means vertically reciprocable within the cylinder means, means for selectively admitting operating fluid to the cylinder means on one side of the piston means so as to move said piston means in one direction and exhausting fluid therefrom to permit said piston means to be moved in the opposite direction, a ring having a surface engageable with and substantially radially coextensive with one end of the outer annulus, means extending sealably through the guideway means and connecting the ring to the piston means, whereby upon movement of the piston means in said one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer from expanded to constricted position, and upon movement of the piston means in the opposite direction, said ring relieves the compression in said outer annulus to permit its inner circumference to expand and thereby permit said packer to move from constricted to expanded position, and means fluidly communicating the housing bore beneath the packer with said recess on the opposite surface of said ring, whereby a force due to the pressure of well fluid acting upon said outer annulus assists the force due to said operating fluid in moving the packer to and maintaining the packer in constricted position.

Claim 30

An annular blowout preventer, comprising a housing having a bore extending vertically therethrough and an annular recess about the bore, a packer comprising an annulus of resilient material mounted in the recess for movement between an expanded position to open the bore and a constricted position to seal about a pipe in the bore or upon itself, another annulus of resilient material surrounding the packer within the recess for moving the packer from expanded to constricted position upon constriction of the inner circumference of the outer annulus, said housing having a cylinder means therein and guideway means connecting the cylinder means with the recess, piston means vertically reciprocable within the cylinder means, means for selectively admitting operating fluid to the cylinder means on one side of the piston means so as to move said piston means in one direction and exhausting fluid therefrom to permit said piston means to be moved in the opposite direction, a ring having a surface engageable with and substantially radially coextensive with one end of the outer annulus, means extending sealably through the guideway means and connecting the ring to the piston means, whereby upon movement of the piston means in said one direction, the ring longitudinally compresses the outer annulus so as to constrict its inner circumference and thereby move said packer from expanded to constricted position, and upon movement of the piston means in the opposite direction, said ring relieves the compression in said outer annulus to permit its inner circumference to expand and thereby permit said packer to move from constricted to expanded position, and means fluidly communicating the housing bore beneath the packer with said recess on the opposite surface of said ring, whereby a force due to the pressure of well fluid acting upon said outer annulus assists the force due to said operating fluid in moving the packer to and maintaining the packer in constricted position.

Claim 31

An annular blowout preventer of the character defined in claim 16, wherein the ring is lower than the piston means.

Claim 32

An annular blowout preventer of the character defined in claim 16, wherein the ring is beneath the annulus so that is upper surface moves upwardly against the lower end of the outer annulus to compress it.

Claim 33

An annular blowout preventer of the character defined in claim 18, wherein the piston means is higher than the ring so as to lift the ring to compress the outer annulus.