GB451825A - A method of and apparatus for taking cores from a drill hole - Google Patents

Abstract

451,825. Boring earth or rock. NAAMLOOZE VENNOOTSCHAP BATAAFSCHE PETROLEUM MAATSCHAPPIJ, 30, Carel van Bylandtlaan, The Hague. Dec. 27, 1935, No. 35846. Convention date, Jan. 23. [Class 85] In core-drilling wherein the drilled core is lifted through the drill pipe by the aid of the flushing liquid, while drilling the flushing liquid is passed down through and up around the drill pipe and for lifting the core, the direction of flow is reversed. In Fig. 1, the core barrel 4 is threaded into position and the bevelled upper end-carries a flap valve 5 opening upwards to permit the passage of the core. An annular valve 10, pressed by a spring 11, permits downward passage of the flushing liquid during drilling, but prevents upward passage of the liquid around the core barrel when raising the core. In Figs. 2a and 2b, the core barrel fits loosely within a guide tube 20 around which the valve 10 is arranged ; the head 21 of the core barrel carries a spring-pressed pawl 26 which engages a shoulder 27 in the drill pipe to hold the barrel during drilling. After drilling, the pawl is released by lowering a cylindrical member 32 which forces inwards the upper end of the pawl and engages below a lip 31 ; the flow of the flushing fluid is then reversed to raise the core and barrel together. The member 32 has a non-return valve 34 for upward passage of fluid and may also have a downwardly opening spring-loaded valve permitting cleaning of the member by the flushing liquid.