GB819160A - Fluid-operated well-drilling mechanism - Google Patents

Abstract

819,160. Liquid-pressure engines. GULF RESEARCH & DEVELOPMENT CO. Jan. 6, 1958 [May 16, 1957], No. 398/58. Class 69 (2). [Also in Group XXI] A liquid-operated percussive drilling mechanism comprises a tubular housing 3, 10, an inverted cup 55 mounted in the housing above a constriction 8, a bit 25 slidable in the housing below the constriction, a hammer 33 within the housing and having sliding contact with the constriction, and a valve 44 slidable within the cup and having a larger diameter than that of the constriction. The drill, comprising a drill string from which the mechanism depends, is run into the hole with the valve, hammer and bit in their lowermost positions relative to the housing so that drilling liquid supplied through openings 7 passes through holes 53 to discharge through the central passages in the valve, hammer and bit. The drill is lowered until the bit touches the bottom of the hole, the mechanism taking up the positions shown in Fig. 5. As the holes 53 are blocked, the liquid pressure raises the valve and hammer until the valve head 48 is about to enter the cup (Fig. 6). From this position the valve accelerates upwardly and the seal 47 between the valve and hammer is broken. The valve and hammer rise to their uppermost positions (Fig. 8) and then fall to the positions shown in Fig. 5 in readiness for a further operational cycle of the mechanism. Springs (not shown) may be respectively mounted in the cup and below the constriction to assist the downward movement of the valve and hammer, and a shoulder may be provided on the hammer neck 36 to cooperate with the constriction to prevent the hammer jamming in its uppermost position. The juncture between bit and housing is formed to transmit torque so that the bit may also be rotated.