Patent GB-839338-A (GB)
Title: Valve apparatus for controlling fluid flow
IPC: E21B33/06
Filed: 1957-08-27
Abstract: 839,338. Wells &c. CAMERON IRON WORKS Inc. Aug. 27, 1957 [July 22, 1957], No. 26988/57. Class 85 [Also in Group XXIX] An oil or gas-well blow-out preventer comprises a forged body 20, Fig. 1, with a fluid conveying throughbore 21. Fig. 7. and a pair of oppositely disposed substantially oval guideways 22 leading therefrom, the outer ends of which are normally closed by hinged bonnets 23, Fig. 1, secured by bolts 25. Slidable within each guideway 22, Fig. 7, is a ram 27 to open or close the bore, in the latter position the inner ram ends are in abutment; each ram is provided with sealing means consisting of a resilient e.g. rubber member 28 across its inner face and an upper member 31. When a pipe runs coaxially through the bore 21 -the engaging face 29 of each member 28 is grooved to fit the pipe otherwise the faces 29 are flat. The rams 27 are moved by rollers 37 disposed in ram slots 38, the rollers being connected by a crank 36 to one or two shafts 35, one at each side of the bore 21, each crank 36 is pivotable in a recess 34 that also serves to admit well fluid from within the bore 21 to the outer ram ends thus urging the rams to the closed position. To facilitate removal of the rams from the guideways each recess is relieved 41, the lowr side of each ram embodies a slot 42 extending from each slot 38 and each guideway is relieved 42a to permit the insertion of a tool and to provide additional clearance. The sides of slots 38 may be' straight, though not necessarily parallel, or curved so long as a large force is available at each end of the ram movement and that such movement is effected at high speed; the slots also ensure that the rams are urged away from the upper parts of the guideways during opening movement to reduce friction. Each shaft 35 is journalled and sealed in the body 20, the bearings being held in position by pins which also serve for the supply of lubricant thereto: externally of the body 20 each shaft is fitted with a crank 55 connected to an actuator 59, Fig. 1. The cranks 55 may lag the interior cranks and the right hand crank 55, Fig. 11, is longer than the other one so that the torque applied thereto is proportionately greater: one crank 55 is connected to the actuator piston 59 whilst the other crank is attached to the actuator cylinder 60. A screw 72 and co-operating part 75a may be used to hold the rams in the closed position when the piston 59 and cylinder 60 are retracted and to enable the rams to be closed manually should the actuator hydraulic supply fail. Each ram consists of upper and lower plates 77, 78, Fig. 14, the upper plate incorporating a groove 79 for housing the seal 31 whilst the lower plate embodies the slot 38. The seal 28, Fig. 7, is made up of parts 29, 30 inserted between the plates, the bottom plate being recessed 80a, Fig. 14, to accommodate the ends of seal 31. The plates are held against relative longitudinal movement by a projection 81 and a groove 82 whilst pins 84 enter slots 85, 86 and retain the seal 28 in place; the latter projects beyond the associated faces of the plates and is prevented from flowing between the plates by members 87. When the rams are in abutment the seals 31 are forced into engagement with guideways, the pins 84 moving rearwardly -in slots 85, 86. The faces of the plates and members 87 form oppositely disposed angles whilst the faces of sealing portions 29 are skewed to guide the pipe in the bore 21, Fig. 7, should it be initially out of alignment in the bore. In a modification, each ram is made as a one-piece body with slots for the seals. The blow-out preventer may be provided with one ram only. Specification 839,339 is referred to.