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).
Testing a gear type hotwell pump and a hotwell injector for an evaporatively cooled system.
| Identifier | ExFiles\Box 179b\4\ img001 | |
| Date | 1st April 1933 | |
| To R.{Sir Henry Royce} from Ha/Pav. C. Sg.{Arthur F. Sidgreaves - MD} G.{Mr Griffiths - Chief Accountant / Mr Gnapp} Rg.{Mr Rowledge} D.{John DeLooze - Company Secretary} Hy.{Tom Haldenby - Plant Engineer} C. Ir. ORIGINAL. Ha/Pav.1/ET.1.4.33. AERO ENGINES. KESTREL. X2444. HOTWELL PUMPS GEAR TYPE & HOTWELL INJECTORS. OBJECT OF TESTS. To develop a reliable system of dealing with the condensate in an evaporatively cooled system. SUMMARY OF RESULTS. The gear type hotwell pump has been tested over several hundred running hours and has proved itself to be unreliable both from the point of view of wear and from the efficiency point of view, the average life of the pump being 40 hrs. but considerable wear takes place after only 2 hrs. The pump runs at high speed and relies solely on water for lubrication. After a few hours running internal leakage became so great that it would not remain primed and working for more than short periods. It was unsatisfactory when attempting to deal with hot condensate water. Three different hotwell pumps tested on the installation hangars all shewed the same characteristics. Ir. some time ago suggested an injection system. Tests have been made with this. The injector worked very satisfactorily. The system is very simple and contains no moving parts. It should be reliable and cannot go wrong. The injector is mounted on the bottom of the hotwell with a non-return ball or flap valve between it and the hotwell to prevent the condenser being flooded when the machine is left standing. A small pipe (1/4" bore) connects the nozzle of the injector to the horn pipe pressure. The injector nozzle works in the throat of a venturi. The depression in the venturi throat sucks in the hotwell condensate and the venturi delivers through another small pipe (1/2" - 3/4" bore) into the main water pipe below the pump inlet. The only disadvantage of the injector system is that the horn-pipe pressure is not large enough to make it work at tick-over speeds. There are two solutions to this problem which do not need any modifications to the standard water pump. (1) The condensate at tick-over speeds is very small, about 1 gall. in 15 mins. The use of a large hotwell sump on the underslung condenser would enable an aeroplane | ||