| 摘要 |
<p>1525938 Centrifugal pumps; gas turbine engine fuel systems GENERAL ELECTRIC CO 27 Nov 1975 [29 Nov 1974] 48799/75 Headings F1C and F1G Fluid such as fuel for a gas turbine engine is delivered by a system comprising primary and booster pumps 16, 12 (which may be centrifugal) connected by a clutch 20; and a machine 14 (which may be a vane type positive displacement pump) driven as a pump by the primary pump drive-shaft 18, during a first operational mode when the output pressure of the primary pump is less than a predetermined value to pump fluid from the primary pump outlet to the system outlet, the machine 14 acting as a motor during a second operational mode, driven by fluid from the primary pump outlet to drive booster pump 12, when the primary pump output pressure reaches or exceeds the predetermined value. Lines 26, 28, 32 convey the fluid pumped by machine 14 to the system outlet during the first mode, check-valve 36 being open and check-valve 38 closed, the pressure being maintained by a valve 50 which provides a bleed path to the primary pump inlet. Booster pump 12 is driven with machine 14 via clutch 20 and pumps fluid via line 22 to pump 16 to prevent cavitation. When the predetermined pressure is reached, an actuator 48 operated by the primary pump output pressure via control means 46 disengages clutch 20, the output pressure also operating a discharge valve 44 to connect the output of machine 14 to the primary pump input causing a pressure drop across the machine which thereby acts as a motor to drive booster pump 12, valve 36 then being closed and valve 38 open. The flow to machine 14 is regulated by a restriction 55 in line 26.</p> |
