GB790455A - Improvements in or relating to expander tools - Google Patents

Abstract

790,455. Tube expanders; sizing and restoring shapes of pipes. LAVAL, C. March 26, 1956, No. 9364/56. Class 83 (4). A tube expander for restoring to shape collapsed portions of oil well pipe comprises means on a housing laterally expansible therefrom to engage the pipe, hydraulic means enclosed within the housing to expand the expansible means and including a pump for the hydraulic fluid driven by an electric motor which can be actuated by means remote from the housing. A tube expander 16 is supported by a cable 14 within an oil well casing 10. The expander housing includes a snap-on top member 24 and an upper section 22 screwed to a boss 26 on a lower section 20. A flat plate 30 supported on the boss 26 carries a hydraulic fluid reservoir 36, an electric motor 38, speed-reducing means 40, a pump 42 for the hydraulic fluid, and an electrically-operated fluid control valve 44. The lower section 20 carries pivoted thereto at 50 expander segments 48 formed with ribs 217. The upper housing section 22 is filled with dielectric fluid to resist external pressures. In operation, a switch 234, at the surface of the well and in supply wires 70 which extend with the cable 14, is closed. This energizes the motor 38 and a solenoid 110 to move a member 102 of the valve 44 against a spring 99 to close an outlet 104 of the valve. Through linkage 78, 80, 82 a piston member 86 of the pump 42 is reciprocated by the motor 38 to force fluid from the reservoir 36 and a reservoir 94 in the pump through a conduit 98 to a chamber 96 in the valve 44. The outlet 104 thereof being closed, fluid passes from the chamber 96 through a conduit 108 to a space above a piston 52, a partially filled gas bag 116 in the reservoir 36 expanding to replace removed fluid. The piston 52 is thus moved down, against a spring 210 to move a further piston 58 loosely linked thereto. The piston 58 moves a rod 56 and head 57 thereon to cause links 224 to expand the segments 48 against springs 220 and 218. To collapse the arms 48, the switch 234 is opened to stop the motor 38 and allow the valve member 102 to move to the position shown in Fig. 3. Thus as the piston 52 is moved up by its spring 210 fluid is forced through the conduit 108, chamber 96, conduit 106, reservoir 94 and conduit 114 to the reservoir 36.