. Model engine construction, with practical instructions to artificers and amateurs. ece of brass, and depends on the length of the stemabove the valve face. To insure success, make thedelivery- and suction-pipes as short as possible, orin other words, have both tank and pump as nearthe boiler as convenient. Action.—The plunger works in and out of thebarrel, leaving a space behind it when drawn out,which is supplied with water through the suction-pipe and lower valve, and this water, not being ableto get past the lower valve, when the plunger ispushed inwards, must force its way past thedelive
. Model engine construction, with practical instructions to artificers and amateurs. ece of brass, and depends on the length of the stemabove the valve face. To insure success, make thedelivery- and suction-pipes as short as possible, orin other words, have both tank and pump as nearthe boiler as convenient. Action.—The plunger works in and out of thebarrel, leaving a space behind it when drawn out,which is supplied with water through the suction-pipe and lower valve, and this water, not being ableto get past the lower valve, when the plunger ispushed inwards, must force its way past thedelivery-valve, and through the delivery-pipe to theboiler. A check-valve ought to be placed at themouth of the delivery-pipe, where it enters theboiler. The injector (see Fig. 24) is an instrument forsupplying a boiler with water, and is used insteadof a pump. It is made from a casting, and is very THE BOILERS AND THEIR FITTINGS. 75 difficult to fit up. A small model does not workwell; there is difficulty with the nozzles, and thesteam is of a low pressure: it does best with high- w. pressure steam. For these reasons we pass it by,except giving a sectional drawing of one, and a shortdescription of how it acts. Steam from the boiler 76 MODEL ENGINE CONSTRUCTION is admitted by pipe S into the injector and passesthrough the nozzle N; this passage is opened andshut, and the amount of steam admitted throughit controlled, by the spindle ; the steam thenruns along the passage D, and past a check-valveinto the boiler. By the suctional action of thecurrent of steam, water is drawn in from the water-tank through the pipe W, and is carried with thepartly-condensed steam through D into the supply of water is regulated by the hand-wheelWRW; O is the overflow-pipe. The valve-spindleV passes through a stuffing-box at the upper partof the injector. Fuel. Small engines should be heated by meansof methylated spirits of wine, or a and ordinary coal are out of the q
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectmachinery, bookyear18
