. The Locomotive. osing, but the percentage in use is very small. The valves are fittedin various ways,— sometimes directly into the boilerplate, more com-monly into water columns of cast iron or those improvised fromordinary pipe and fittings. The openings to receive the valves shouldbe parallel and threaded an equal depth, so that when the valvesthemselves are screwed in position the sockets in them for the recep-tion of the glass will be in a direct line. Both top and bottom valveshave these sockets bored out to a considerable depth. If the eyecannot detect the valves out of line, the glass
. The Locomotive. osing, but the percentage in use is very small. The valves are fittedin various ways,— sometimes directly into the boilerplate, more com-monly into water columns of cast iron or those improvised fromordinary pipe and fittings. The openings to receive the valves shouldbe parallel and threaded an equal depth, so that when the valvesthemselves are screwed in position the sockets in them for the recep-tion of the glass will be in a direct line. Both top and bottom valveshave these sockets bored out to a considerable depth. If the eyecannot detect the valves out of line, the glass should be inserted inthem, to more clearly determine whether the valves are in true align-ment or not. The glass should be cut to the greatest length that willpermit its insertion, one cock or valve usually admitting it to a greaterdepth than the other. In the selection of a glass, one should be used that will freelyenter the valve receptacle and leave a little space around it when in 8 THE LOCOMOTIVE [January,. position, and the nuts or glands for compressing the gaskets shouldbe large enough not to touch the glass when screwed up. Only fresh,pure rubber gaskets or washers cut by machine, uniform in size, andprepared for such purpose should be used. After inserting the glassin the valves, it should be shifted so the washers will be at an equaldistance from its ends. This is very important, for the writer inhis investigations of boiler explosions has found two instances wherea washer softened by the heat, under pressure of the gland, hassqueezed out under the glass and closed the opening, thus permitting a false indication of the water level.[Editors Xote — Fig. 3 illustratessuch an obstruction which recentlycame to the attention of the Bureauof Locomotive Inspection of the In-terstate Commerce Commission.]The glands should first be screwedby hand, each a little in turn untilthey can no longer be moved by thefingers. Then a small wrench maybe used on them alternately, unti
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Keywords: ., bookauthorhartfordsteamboilerin, bookcentury1800, bookdecade1860
