. Supplement to Spons dictionary of engineering, civil, mechanical, military, and naval. hen riveted, when the holder is lowered to its bearings and the long screwsremoved. This effected, the upper guide rollers are then fixed accurately in their positions. Amanhole is left in the roof, so that after the interior of the holder is painted, the scaffolding can beremoved at that point; it is also intended for the purpose of clearing out any obstruction that mayoccur in the pipe. The telescopic holder, which under some conditions is advisable, is comprised of a single vesselof the ordinary constru
. Supplement to Spons dictionary of engineering, civil, mechanical, military, and naval. hen riveted, when the holder is lowered to its bearings and the long screwsremoved. This effected, the upper guide rollers are then fixed accurately in their positions. Amanhole is left in the roof, so that after the interior of the holder is painted, the scaffolding can beremoved at that point; it is also intended for the purpose of clearing out any obstruction that mayoccur in the pipe. The telescopic holder, which under some conditions is advisable, is comprised of a single vesselof the ordinary construction, guided at the top by rollers working against the guide standards, andsurrounded at its base by an annular cup c, of from 12 in. to 18 in. in depth and from 6 to 9 in. in•width, Fig. 1381. This inner holder is enclosed by a cylinder or outer lift concentric to it, of some-what larger diameter, but about the same depth. To the top of this outer cylinder is attached anannular grip 6 6, corresponding with the cup. Thus, each time that the inner holder is filled when HAMMEES. 687. ascending, it lifts the lower holder, and as the cup is always filled with water when rising, on thegrip being immersed therein a hydraulic joint extending the circumference of the holder is these means, so long as the holder retains its level position, and in the absence of a pressuresuperior to that of the dip, the gas is retained. The rollers c? and a are for the purpose of preventingany unnecessary play, which would be fatal to the action of the apparatus. In telescopic holders of 90 ft. in diameter and under, the upper lift is generally counterbalanced,but when of larger dimensions their great area renders this no longer necessary. The choice of a position for a large gas-holder, where choice can be had, requires careful andjudicious inquiry on the part of the engineer. Eocks and water-springs ought, if possible, to beavoided; the fiist largely increasing the cost of excavations, an
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectenginee, bookyear1879
