[LB063370], Letter from Thomas Alva Edison to William Lawrence Saunders, Ingersoll-Sergeant Drill Co, March 3rd, 1899
https://edisondigital.rutgers.edu/document/LB063370
Transcription
Mar 3, 1899. Mr. W. L. Saunder’s % Ingersoll-Sergeant Drill Co., 26 Cortlandt St., New York. Dear Sir: My man reports as follows on the testing scheme presented to us. Sources of Error in Air Reheater Testing Plant as advised by the Ingeroll-Sergeant Drill CO. The pump must be run at a pressure lower than that of the receiver to obtain regulation of receiver pressure. When the speed of the pump is increased by putting on the heater, the pressure on which the pump works, must be increased owing to the inertia of water, friction in pipes, valves etc. Working under higher pressure, in this manner more air will be exhausted per stroke and work will be done by the air which is not credited to it. One of the advantages of reheating the air, is the increased expansion that can be allowed in an engine without too great chilling of the air. This can not be shown in a pump where there is no expansion.