The surface-condenser is cleared by a single-acting air-pump, inside the frame, at T.
The piston will, therefore, be pressed downwards by the action of the steam above it, as in the single-acting engine.
A chain from the piston-rod to the arch head, as described in the single-acting engine, would fail to transmit this force.
The piston P is accurately fitted in the steam cylinder C by packing, as already described in the single-acting engine.
By single-acting is meant that the air cylinders compress their respective volumes of air once every revolution.
As single-acting pumps give an intermittent discharge three are generally used on cranks at 120.
The small engine drives a single-acting air pump of the ordinary type by a crank, not shown in the drawing.
The engine, it will be seen, is single-acting, and no compression of the explosive charge is employed.
single-acting cylinders are cylinders in which the steam expands on only one side of the piston.
Each sliding platform was actuated by two single-acting rams, 3½ in.
