STATIONARY ENGINES.

injection valve. Besides the ordinary steam and exhaust valves,there is a valve worked by hand for regulating the descent of the

Fig. 117.—Overhead-beam Pumping Engine. End Elevation.

piston, and placed at the bottom of the passage leading to the topof the cylinder. The feed pump is of the plunger type, workeddirectly off the overhead beam; the suction valve is placed at the