Lubrication/cooling system having an independent auxiliary backup reservoir

摘要

A lubricating and cooling system 2, 3 for a mechanical assembly, such as a helicopter transmission gear box 1, comprises (i) a primary device 2 which circulates a stream of lubricant/coolant liquid such as oil in a closed-loop circuit 4 from a main tank 9 to the mechanical assembly 1 at a relatively high pressure, (ii) an auxiliary backup device 3 which can be manually or automatically operated when the primary device 2 becomes defective further comprises (iii) at least one lubricant/coolant liquid reservoir 10 which is independent of the primary device, (iv) at least one source of pressurised gas 11, (v) at least one spray nozzle 17, 18 which is fed with pressurised gas and with liquid from the reservoir 10 at a maximum pressure of 2 x 105 Pa (2 bar), and which is able to spray a mist of the liquid on to the mechanical assembly 1 when the primary device 2 is rendered defective. This pressure is significantly lower than that of the main device and as such allows efficient and prolonged used of the backup device when necessary. Operation of backup device 3 may commence via manually operating valve 13 or by the activation of control valve 13 by pressure sensor 29. The primary device 2 also incorporates a pump 5, a liquid introducer 6, a liquid collector 7 and a filter 8. The backup device 3 furthermore includes filters 12, 24 and 27, a cooler 14, non-return valves 23 and 26, a flow limiter 25 and nozzle feed devices 20 and 21.