Patent GB-780298-A (GB)
Title: Pipe suspensions and sealing means
IPC: E21B33/04
Filed: 1956-01-13
Abstract: 780,298. Well casing heads. BUTLER, G. A. Jan. 13. 1956 [April 4, 1955], No. 1266/56. Class 85 A pipe suspension and seal apparatus includes a well or casing head 30 having upper and lower seats 55, 43, and a pipe hanger 40 provided with upper and lower shoulders 54, 42 respectively adapted to engage the seats, the axial distance between the seats being different from that between the shoulders when a pipe is not disposed in the hanger whereby when the latter is initially placed in the head without pipe load only one of the shoulders 54 engages the corresponding seat 55. Sealing means 52 for sealing between the hanger and well head are disposed in the connection between the parts of the hanger, and the latter is provided with means to engage a pipe to transfer weight to the part of the hanger having the shoulder 42 that is not initially engaged on the seat 43, the sealing means shortening axially when pipe load is transmitted thereto until the shoulder 42 is seated. As shown in Fig. 1, the head 30 is secured to the upper end of a casing 31, and a pipe 32 supported by the head extends into and is sealed to the lower -portion of a head 33. The hanger 40, Figs. 7 and 8, is in halves pivotally connected together by a spring hinge 45 located in a channel 47, a snap latch 48 being arranged oppositely of the hinge; a dowel pin 49<SP>1</SP> maintains, alignment of the halves of the hanger. The top portion of the hanger is formed by a compression ring 51 and a support ring 50, both rings being in halves, and disposed between those rings is a split sealing ring 52 of neoprene; the three rings are held together by and are slidable on a number of screws 53 engaged in the lower part 41 of the hanger. The conical shoulder 54 is formed on the ring 50, and the shoulder 42, also conical, is provided on the part 41. The latter has an internal conical recess 60 within which are disposed a number of slips 61 each provided with a tapped recess 62 which can be aligned with one of a number of holes 63 in the hanger whereby a screw retains each slip in a retracted position as shown in Fig. 2A, those screws being removed after the hanger is placed around the pipe 32 and before the latter is lowered into the head; the slips are maintained in vertical alignment by the engagement of a pin, secured to one side of each slip, with a groove in the adjacent slip. Each slip is formed internally with a number of upwardlydirected teeth 66 of modified buttressthread cross-section and, externally, with a number of downwardly-directed teeth 67 also of buttress-thread cross-section and having flat crests 68. In operation, when the hanger is placed in the head 30 the top of the part 41 of the hanger is in contact with the ring 50, Fig. 2A, and the hanger is seated on the shoulder 55 of the. head. Lowering of the pipe 32 causes the slips to move downwardly in the recess 60 and the hanger to seat on the shoulder 43, the screws 53 consequently drawing the ring 51 down to radially expand the ring 52 against the head and the pipe. Where that portion of the weight of the pipe transferred to the screws is insufficient to cause the ring 52 to form a good seal, additional pressure is placed upon the ring by screws 57 extending through a flange of the head 30 and engaging a bevel on the ring 51. The slips are hardened so that the teeth 66 and 67 respectively bite into the surfaces of the pipe and recess 60.