GB547065A - Earth boring apparatus of the core drilling type - Google Patents

Abstract

547,065. Borehole apparatus. STANDARD OIL DEVELOPMENT CO. Feb. 10, 1941. No. 1764. Convention date, Feb. 10, 1940. [Class 85] In a core-boring apparatus in which the core is received in a pressure chamber capable of being sealed in a fluid tight manner, a fluid tight expansible member is provided in connection with the chamber whereby the pressure differential is reduced as the core is raised to the surface. In Fig. 1, the drill stem 5 encloses a cylinder 35 connected to a block 36 provided with fluid passages 38, 39, a depending knife edge 53, guide fins 64 and a longitudinal passage 40 controlled by a needle valve 41 and leading to a lateral passage 42 normally closed by a plug 43. Inside cylinder 35, the core barrel depends from a collar 51 carried by a rod 25 passing slidably through block 36 and connected by coupling 24 to a rod 20, the coupling 24 having limited longitudinal movement relative to a sleeve 44 with fins 47 forming a seat for the bevelled edge of a cylinder 7 connected by linkage to the rod 20. An expansible rubber sleeve 101 is held by clamps 102 around an apertured part of cylinder 35. In use, when the core barrel strikes the bottom of the hole, rods 25, 20 are forced upwardly and rod 20 is locked to cylinder 7; the core is then cut, displaced fluid passing through passages 38, 39. Cylinder 7 and rod 20 are then raised to move the core barrel within cylinder 35 to allow a valve to close the lower end of the latter, and resilient material 52 on the collar 51 contacts the knife edge 53 to close the upper end. The core barrel is then raised to the surface, during which movement, the pressure differential is reduced by expansion of the rubber sleeve 101. The plug 43 may then be removed and collecting means connected to passage 42 to receive volatile matter from the core barrel on opening valve 41. In Fig. 2, the rubber sleeve 101 is replaced by a bellows 105 connected by passage 104 with the interior.of cylinder 35; in other forms, the bellows is replaced by a rubber balloon or by a telescoping member.