GB446657A - Improvements relating to casing head equipment for bore holes or wells - Google Patents

Abstract

446,657. Boreholes and wells. SEAMARK, L. M. C., Elmwood House, Petersfield, Hampshire. July 30, 1934, Nos. 17766 and 26724. [Class 85] A casing head equipment for boreholes and wells comprises a casing containing a massive sleeve of rubber &c. through which drill stems, casing tubes &c. may pass, and a piston and cylinder or equivalent device actuated by fluid pressure to effect axial compression and consequent inward contraction of the sleeve. In Fig. 1, a massive elastic sleeve f is moulded in one piece or formed of superposed rings or parts thereof; the superposed rings may have interlocking ribs and recesses and may be slit, slits of adjoining rings being out of line, while the bore of the rings may have curved &c. walls. An annular piston a is mounted on or engaged with the sleeve f and is depressed by fluid from the well or from a hydraulic accumulator &c. admitted through passage d<6> to contract the inner diameter of the sleeve. A tube b extends upward from the piston and the weight of the drill stem &c. may be applied thereto to act on the sleeve f. The cylinder cap d may be secured by bayonet joints or by a threaded joint and locked by a member d<5> engaging recesses. An air release plug j is provided and passages d<1> formed in the cylinder or in the tube b and provided with similar plugs permit escape of fluid leaking past the piston. In Fig. 7, the sleeve f, piston a and cylinder g are rotatably supported in an outer casing c by ball bearings p, p<1>, the fluid supply passing through an apertured ring q<2> bearing on packing and adjusted by screws q. Below the sleeve f, a packer l may be provided for contraction by external pressure as described in Specifications 358,419 and 389,513 ; such packer is preferably formed of oil-proof synthetic rubber. A flexible diaphragm may replace the piston a.