[Illustration:  Fig. 63.]

Fig. 63 is a perspective view of H.R.  Worthington’s Duplex Steam Pump.  The prominent peculiarity of this pump is its valve motion.  As seen in the cut, two steam pumps are placed side by side (or end to end, if desired).  Each pump, by a rock shaft connected with its piston rod, gives a constant and easy motion to the steam valve of the other.  Each pump therefore gives steam to and starts its neighbor, and then finishes its own stroke, pausing an instant till its own steam valve, being opened by the other pump, allows it to make the return stroke.

This combined action produces a perfectly positive valve motion without dead points, great regularity and ease of motion, and entire absence of noise or shock of any kind.  Both kinds of pumps are made by Mr. Worthington, of various size according to the requirements, the duplex being used for boiler feed and for the supply of cities with water.

Fig. 64 is a side elevation of the Woodward Steam Pump.  The pump is direct acting.  The steam and water piston being on the same rod, but momentum is obtained to throw the valves by means of a fly wheel, placed beyond the pump, and connected with the piston rod by a cross head and a yoke.  The machine is simple in its construction and action, and is extensively used.

Giffard’s Injector, both in Europe and this country, is quite extensively used to supply the place of a pump, as independent feed for all classes of boilers.  It is represented in elevation and section, figs. 65 and 66.

[Illustration:  Fig. 64.]

[Illustration:  Fig. 65.]

[Illustration:  Fig. 66.]

A, steam pipe leading from the boiler. B, a perforated tube or cylinder, through which the steam passes into the space b. C screwed rod for regulating the passage of steam through the annular conical space c, and worked by the handle d/. E, suction pipe, leading from the tank or hot well to small chamber m. F, annular conical opening or discharge pipe, the size of which is regulated by the movement of the tube or cylinder B. G, hand wheel for actuating the cylinder B. H, opening, in connection with the atmosphere, intervening between discharge pipe F and the receiving pipe through which the water is forced. I, tube through which the water passes to the boiler. K, valve for preventing the return of the water from the boiler when the injector is not working. L, waste or overflow pipe. M, nut to tighten the packing rings g and upper packing i in cylinder B. N, lock nut to hold M.

The pipe A is connected with the steam space of the boiler at its highest part, to obtain as dry steam as possible.  The passage of the steam into A is controlled by a cock, as is also the feed pipe to the boiler.  In working, both are opened, the steam passes through A into the space b, and issuing through the nozzle c with the pressure due to its head, and a partial vacuum by its contact with the feed water, it drives this water in connection with the jet through the pipe F into the pipe I in connection with the water space of the boiler.