Tubular Perforators.—Mr. Gay has rendered his saw completer by the invention of a tubular perforator for drilling the preliminary well. It is based upon the same principle as the Leschot rotary drill, but differs from that in its extremity being simply of tempered steel instead of being set with black diamonds. A special product, called metallic agglomerate, is used instead of sand for hastening the work.
FIG. 6.—TUBULAR PERFORATOR.
The apparatus, Fig. 6, consists of an iron plate cylinder, A, 27½ inches in diameter, and of variable length, according to the depth to be obtained, and terminating beneath in a steel head, B, of greater thickness. This cylinder is traversed by a shaft, C, to which it is keyed, and which passes through the center of the aperture drilled. This shaft is connected with the cylinder, A, through the intermedium of cross bars, D, and transmits thereto a rapid rotary motion, which is received at the upper part from a telodynamic wire that passes through the channel of the horizontal pulley, P. This latter is supported by a frame consisting of three uprights, Q Q, strengthened by stays, R R, fixed to the ground.
In order that the cylinder, A, may be given a vertical motion, cords, M M, fixed to a piece, S, loose on the hub, D, wind round the drum of a windlass, T, after passing over the pulleys, p p.
The rapid gyratory motion of the cylinder, along with the erosive action of the metallic agglomerate, rapidly wears away the rock, and causes the descent of the perforator. During this operation a core of marble forms in the cylinder. This is detached by lateral pressure, and is capable of being utilized. The tool descends at the rate of from 20 to 24 inches per hour, or from 8 to 10 yards per day in ordinary lime rock.—Le Genie Civil.
PORTABLE PROSPECTING DRILL.
