SELLERS INJECTOR.
When the Giffard injector was first introduced into this country, by William Sellers & Co., Philadelphia, it was a very defective boiler-feeder; but that firm effected great improvements, and led the way for making the injector the popular boiler-feeder it is to-day. They made the instrument self-adjusting, and improved its design, so that it would automatically feed, however much the pressure of the boiler varied. After numerous changes, the injector of 1876 was produced, which is shown by a sectional view in [Fig. 2]. The Sellers injector of to-day remains substantially the same as it was when exhibited at the Centennial Exposition.
Fig. 2.
Referring to [Fig. 2], A is the receiving-tube, which will be closed to the admission of steam by the valve X. A hollow spindle passing through the receiving-tube into the combining-tube, is secured to the rod B; and the valve X is fitted to this spindle in such a way, that the latter can be moved a slight distance (until the stop shown in the figure engages with valve X) without raising the valve X from its seat. A second valve, W, secured to the rod B, has its seat in the upper side of the valve X, so that it can be opened (thus admitting steam to the center of the spindle) without raising the valve X from its seat, if the rod B is not drawn out any farther, after the stop on the hollow spindle comes in contact with the valve X. D is the delivery-tube, O an overflow opening into space C, K the check-valve in delivery-pipe, and P R the waste-valve. The upper end of the combining-tube has a piston N N attached to it, capable of moving freely in a cylindrical portion of the shell M M; and the lower end of the combining-tube slides in a cylindrical guide formed in the upper end of the delivery-tube.
The rod B is connected to a cross-head, which is fitted over the guide-rod J; and a lever H is secured to the cross-head. A rod L, attached to a lever on the top end of the screw waste-valve, passes through an eye that is secured to the lever H; and stops T, Q, control the motion of this rod, so that the waste-valve is closed when the lever H has its extreme outward throw, and is opened when the lever is thrown in so as to close the steam-valve X; while the lever can be moved between the positions of the stops P, Q, without affecting the waste-valve. A latch V is thrown into action with teeth cut in the upper side of the guide-rod J, when the lever H is drawn out to its full extent, and then moved back; and this click is raised out of action as soon as it has been moved in far enough to pass the last tooth on the rod J. An air-vessel is arranged in the body of the instrument, as shown in the figure, for the purpose of securing a continuous jet when the injector and its connections are exposed to shocks, especially such as occur in the use of the instrument on locomotives.
The manipulation required to start the injector is exceedingly simple,—much more so in practice, indeed, than it can be rendered in description. Moving the lever H until contact takes place between valve X and stop on hollow spindle, which can be felt by the hand upon the lever, steam is admitted to the center of the spindle, and, expanding as it passes into the delivery-tube D and waste-orifice P, lifts the water through the supply-pipe into the combining-tube around the hollow spindle, acting after the manner of an ejector or steam-siphon. As soon as solid water issues through the waste-orifice P, the handle H may be drawn out to its full extent, opening the steam-valve X, and closing the waste-valve, when the action of the injector will be continuous as long as steam and water are supplied to it.