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From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Preliminary test report on using a Claudel-Hobson air-driven petrol pump as a hotwell pump for evaporatively cooled engines.

Identifier  ExFiles\Box 61\3\  scan0338
Date  24th August 1932
  
X4038 b.

To Rg.{Mr Rowledge} from Hs{Lord Ernest Hives - Chair}/Aln.
c. to Lr.{Mr Ellor}

Hs{Lord Ernest Hives - Chair}/Aln.5/KT.24.8.32.

AIR DRIVEN HOTWELL PUMP.

A preliminary test has been carried out using the Claudel-Hobson air driven petrol pump reported in Hs{Lord Ernest Hives - Chair}/Aln.1/MA.1.4.32., as a hotwell pump, with a view to its application to the evaporatively cooled engines.

The condensate to be handled amounts to about 8 pints per min. with the Kestrel engine, and 12 pints with the Buzzard, temperatures being up to 98°C.

After a few rough trials the pump was arranged 6 ft above a water tank and the suction connected to it. The delivery was taken through a cock and a pressure gauge was attached on the pump side of the cock. An air pressure supply of anything up to 80 lbs per.sq.in. was arranged and an adjustable needle valve was included in the air line in addition to the main cock.

The needle valve was adjusted so that at 30 lbs per.sq.in. of air, the pump would deliver about 8 pints per min. the delivery cock being adjusted to represent about 4 ft. head. With this setting of the needle valve it was found that the pump would self-prime in about 20 secs. It would also continue to run at a moderate speed if it were allowed to draw air instead of water. The water temperature was about 95°C. The possible rate of pumping we found was many times 8 pints per minute.

After a time the rate of pumping began to fall off and eventually it failed altogether although the pump continued to reciprocate faultlessly. On dismantling this appears to be due to hardening of the cup leathers which are fitted to each of the pistons.

The particular construction of this pump in which the air and the liquid are on opposite sides of the same piston is adapted for use with petrol, with object of avoiding glands through which the petrol might leak. This would not be so important in the case of pumping water and probably a construction in which the air and water barrels are separate, and the pistons joined by a rod passing through glands, would be more suitable. The air pistons would then still be fitted with cup leathers, but these would not be subject to water and heat.

Hs{Lord Ernest Hives - Chair}/Aln.
  
  


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