초록 ▼

A ram seal element adapted for use with a ram block and ram block holder in a blow out preventer apparatus to provide sealing of drill strings of varying diameters. The ram seal element is a semi-circular elastomer having a diametrical portion and a circumferential portion. The diametrical portion i

A ram seal element adapted for use with a ram block and ram block holder in a blow out preventer apparatus to provide sealing of drill strings of varying diameters. The ram seal element is a semi-circular elastomer having a diametrical portion and a circumferential portion. The diametrical portion includes a center collar section and two side sections with the collar section being adapted for sealing contact with the drill string. The diametrical portion is provided on its outer side surface with a longitudinal channel defining an expansion zone into which the seal can expand uniformly to accommodate drill strings of increasing size.

대표청구항 ▼

1. A ram seal element for use in the ram assembly of a blow out preventer, said ram seal element being adapted to provide sealing of variable diameter drill strings to prevent blow out of well pressure when said drill strings are in use within said well, said ram assembly including a ram block for b

1. A ram seal element for use in the ram assembly of a blow out preventer, said ram seal element being adapted to provide sealing of variable diameter drill strings to prevent blow out of well pressure when said drill strings are in use within said well, said ram assembly including a ram block for biasing said ram seal element against said drill string and a ram block holder for mounting said ram block within said blow out preventer, said ram seal element comprising: a semi-circular elastomer having a diametrical portion and a circumferential portion, said diametrical portion having an inner side sealing surface, top and bottom surfaces and an outer side surface, said diametrical portion further including an elastomer central collar section and two elastomer side sections, said collar section having an inner surface defining an arcuate recess in the sealing surface of said diametrical portion for sealing contact with a drill string, wherein the outer side surface of said diametrical portion is adapted for contact with said ram block, said ram block being movable toward said drill string to bias said diametrical portion against said drill string, said outer surface including a longitudinal channel therein extending substantially the entire length of both said central collar section and side sections of said diametrical portion and being sealed off from said well pressure, said channel defining an expansion zone between said diametrical portion and said ram block when said ram seal element is in sealing portion in said ram assembly, wherein said expansion zone has a sufficient volume to allow uniform expansion of said diametrical portion into said expansion zone when said seal is used to seal drill strings of increasing diameter, said seal element thereby being useful to provide sealing of variable diameter drill strings to prevent blow out of well pressure when said drill strings are in use within said well. 2. A ram seal element according to claim 1 wherein said inner side sealing surface and said outer side surface are substantially parallel. 3. A ram seal element according to claim 1 wherein means associated with said outer side surface are provided for aligning and mounting said seal element relative said ram block. 4. A ram seal element according to claim 1 wherein said diametrical portion of said seal element includes an upper ridge and a lower ridge extending longitudinally across said outer side surface, said upper ridge being adjacent said diametrical portion top surface and said lower ridge being adjacent said diametrical portion bottom surface, said upper ridge having a lower surface and said lower ridge having an upper surface, said ridge upper and lower surfaces defining a bottom and a top of said channel. 5. A ram seal element according to claim 1 wherein said diametrical portion includes anti-extrusion means for preventing deformation of said collar. 6. A ram seal element according to claim 5 wherein said anti-extrusion means include a plurality of rigid bars located at spaced locations along the top and bottom surfaces of said collar portion, said rigid bars having outer surfaces which are mounted flush with the bottom or top surfaces of said collar. 7. A ram seal element according to claim 6 wherein said rigid bars including inner surfaces having dowel pins extending therefrom into said collar to secure said rigid bars to said collar. 8. A ram seal element according to claim 7 wherein said collar is sized to fit smaller diameter drill strings, said collar being sufficiently resilient to expand outward to accommodate larger diameter drill strings. 9. A ram assembly for use in a blow out preventer, said ram assembly being adapted to provide sealing of variable diameter drill strings to prevent blow out of well pressure when said drill strings are in use within said well, said ram assembly comprising: a ram block; a ram block holder for mounting said ram block within said blow out preventer; and two ram seal elements disposed on opposite sides of said drill string, each of said ram seal elements comprising a semi-circular elastomer body having a diametrical portion and a circumferential portion, said diametrical portion having an inner side sealing surface, top and bottom surfaces and an outer side surface, said diametrical portion further including an elastomer central collar section and two elastomer side sections, said collar section having an inner surface defining an arcuate recess in the sealing surface of said diametrical portion for sealing contact with the drill string, wherein the outer side surface of said diametrical portion is adapted for contact with said ram block, said ram block being movable toward said drill string to bias said diametrical portion against said drill string, said outer surface including a longitudinal channel therein extending substantially the entire length of both said central collar section and side sections of said diametrical portion and being sealed off from said well pressure, said channel defining an expansion zone between said diametrical portion and said ram block when said ram seal element is in sealing position in said ram assembly, wherein said expansion zone has a sufficient volume to allow uniform expansion of said diametrical portion into said expansion zone when said seal is used to seal drill strings of increasing diameter, said seal element thereby being useful to provide sealing of variable diameter drill strings to prevent blow out of well pressure when said drill strings are in use within said well. 10. A ram assembly according to claim 9 wherein said inner side sealing surface and said outer side surface are substantially parallel. 11. A ram assembly according to claim 9 wherein means associated with said outer side surface are provided for aligning and mounting said seal element relative said ram block. 12. A ram assembly according to claim 9 wherein said diametrical portion of said seal element includes an upper ridge and a lower ridge extending longitudinally across said outer side surface, said upper ridge being adjacent said diametrical portion top surface and said lower ridge being adjacent said diametrical portion bottom surface, said upper ridge having a lower surface and said lower ridge having an upper surface, said ridge upper and lower surfaces defining a bottom and a top of said channel. 13. A ram assembly according to claim 9 wherein said diametrical portion includes anti-extrusion means for preventing deformation of said collar. 14. A ram seal assembly according to claim 13 wherein said anti-extrusion means includes a plurality of rigid bars located at spaced locations along the top and bottom surfaces of said collar portion, said rigid bars having outer surfaces which are mounted flush with the bottom or top surfaces of said collar. 15. A ram seal comprising two ram seal elements in accordance with claim 1 having their sealing surfaces located adjacent each other with the center collar sections aligned to provide a drill string orifice in which variable sized drill strings are sealed by said ram seal. 16. In a ram seal for use in sealing variable diameter drill strings to prevent blow out of well pressure, wherein said ram seal includes two seal elements each of which comprises a semi-circular elastomer body having a diametrical portion and a circumferential portion, said diametrical portion having an inner side sealing surface, top and bottom surfaces and an outer side surface, said diametrical portion further including an elastomer central collar seciton and two elastomer side sections, said collar section having an inner surface defining an arcuate recess in the sealing surface of said diametrical portion for sealing contact with a drill string, wherein said seal elements are located on opposite sides of the drill string to form a circular ram seal having a central drill string orifice defined by the arcuate recesses in said diametrical portions of the seal elements, said seal elements defining a first small diameter orifice when said seal elements are in an unexpanded position and said seal elements defining a second large diameter orifice when they are in an expanded position, wherein the improvement comprises: providing said outer side surface of each seal element with a longitudinal channel therein extending substantially the entire length of both said central collar section and side sections of said diametrical portion, said channel being sealed off from said well pressure, said channel defining an expansion zone having sufficient volume to allow uniform expansion of said seal elements into said expansion zone when said seal elements are moved from said unexpanded position for sealing to relatively small diameter drill strings to said expanded position for sealing to drill strings relatively large diameters.