Ans. The steam pipe should be short to reduce the loss of heat between engine and boiler to a minimum, and both short and direct to avoid undue friction and consequent drop in pressure of the steam in passing through the pipe to the engine.
Entirely too little attention is given to this matter on the part of designers and it cannot be too strongly emphasized that, for economy, the steam pipe between an engine and boiler should be as short and direct as possible, having regard of course, for proper piping methods.
Ques. What should be provided for the steam pipe?
Ans. A heavy covering of approved material should be placed around the pipe to reduce the loss of heat by radiation. For this purpose hair felt, mineral wool and asbestos are used.
Fig. 2,724.—View of engine and condenser, showing how to arrange the piping to secure good vacuum. Locate the condenser as near the engine as possible; use easy bends instead of elbows; place the pump below bottom of condenser so the water will drain to pump. At A is a relief valve, for protection in case the condenser become flooded through failure of the pump, and at B is a gate valve to shut off condenser in case atmospheric exhaust is desired to permit repairs to be made to condenser during operation. A water seal should be maintained on the relief valve and special attention should be given to the stuffing box of the gate valve to prevent air leakage. The discharge valve of the pump should be water sealed.
Ques. How should the piping be arranged between the engine and condenser, and why?
Ans. It should be as short and direct as possible; especially should elbows be avoided so that the back pressure on the engine piston will be reduced as near as can be to that of the condenser.
That is to say, in order to get nearly the full effect of the vacuum in the condenser the frictional resistance of the piping should be reduced to a minimum.