Page:The American Cyclopædia (1879) Volume I.djvu/814

 778 ARTESIAN WELLS and similar in character to the common hoist- ing windlass. Upon each end of this shaft is driven a large pulley called the bull wheel; between these, upon the main shaft, the drill rope, a cable of from li to 11 in. in diameter, is coiled, the outer end passing from it over the pulley on the top of the derrick, and attached to the drilling tools. When these are to be lowered or withdrawn, it is done by means of power applied to the bull wheel. In localities where the rock is some distance below the surface, it is customary to drive down, by the aid of a suitable weight and guideway, a heavy SAND. SINKER |! BIT REAMER PUMP BAR Boring Tools. metal pipe, called the drive pipe ; this is usu- ally of cast iron, from 6 to 8 in. in diameter and an inch in thickness ; it is driven in sec- tions of 10 ft., and great care is needed that it be not bent or deflected, since it is to guide the drilling tools. The engine is BO placed that its drive or balance wheel shall be from 20 to 25 ft. from the centre of the derrick, and at one half this distance is planted the sampson post, a heavy hewn timber from 12 to 18 in. square and 12 ft. high, the top of which is fitted to receive the working beam. This working or walking beam transmits and ap- plies the power to the drills ; it is of wood, 12 or 16 in. square, and of such a length that when balanced upon the sampson post one end may stand directly over and connect, by means of a connecting rod, with a crank attached to the shaft of the drive wheel ; by the revolu- tion of this crank, which has a radius of about 20 in., a reciprocating movement is given to the further end of the working beam ; on this is bolted an iron joint, to which may be at- tached the temper screw when drilling, or the sucker rods when pumping. The drilling tools consist of centre bits, reamers, an auger stem, jar, and sinker bar, with a socket for attach- ing this last to the drill rope. The centre bit is of 2i-inch wrought iron, 3J ft. long, and having a wedge-shaped cutting edge of steel, 3 to 6 in. on the face. The reamer, which follows this and serves to enlarge and trim out the hole, is very similar in shape, though about an inch broader on the face, which is also more blunt ; the average weight of each is about 75 Ibs. The auger stem, into which bits, reamers, and dislodging tools are screwed, is a wrought- iron bar about 20 ft. long. The sinker bar, a heavy rod of iron 10 ft. long, serves to in- crease the force of the blow ; it is separated from the auger stem by an ingenious contriv- ance called a jar, consisting of two links or loops of iron or steel, which slide in upon each other when the drill strikes bottom, thus, by a quick blow upon the top of the auger stem, in- creasing the effect of the fall ; and on the up- ward movement the sudden jerk or jar serves to loosen the tools, in case they become wedged. When connected, these tools weigh from 800 to 1,600 Ibs., as the hardness of the rock re- quires. The drill rope is attached to the work- ing beam by means of a temper screw, sus- pended from it and made fast to the rope by a screw clamp. This temper screw is about 3 ft. long, and is made with a coarse thread that works in a thin frame. At the lower end of this screw is a wheel, by which it is let down after each stroke, whereby the tension is regulated and the drill properly guided. The tools are lifted and dropped by the rocking motion of the working beam, and lowered or withdrawn by aid of the bull wheel and shaft. The sediment and battered rock is removed by means of a sand pump, which is a heavy metal tube, slightly smaller than the well bore, and about 6 ft. long, with the lower end closed by a simple valve opening upward ; this is lowered and withdrawn by a light rope, and the well- man by an examination of its contents is in- formed of the progress and prospects of his work. The pump is used after each drilling of 6 to 12 in. The tubing of a well consists in lowering down a heavy iron pipe in sections, the joints of which are flush both inside and out. At the lower end of the first section lowered down is a simple ball-valve pump, the piston