Hydraulic-pneumatic power transfer unit

A hydraulically powered pneumatic intensifier for supplying compressed air from a gas turbine engine comprising:

• a block like housing;
• two first stage air chambers contained within said housing and arranged along a first common longitudinal axis, each chamber in communication with a source of air to be compressed and each in communication with a first stage air transfer pipe;
• check valves between each of said air chambers and the source of air, adapted to allow air to enter but not leave said chambers;
• a pair of first stage air pistons, one in each of said chambers, connected together by a first link and adapted to reciprocate within said chambers along said common longitudinal axis;
• a second stage air chamber and a third stage air chamber contained within said housing and located along a second common longitudinal axis;
• said second axis being parallel to said first axis so that all of the chambers lie in a common plane;
• said second stage air chamber in communication with said first stage air transfer pipe and also in communication with a second stage air transfer pipe;
• said third stage air chamber in communication with said second stage air transfer pipe and also in communication with a third stage air delivery pipe;
• a second stage air piston with said second stage air chamber and adapted to reciprocate therein;
• a third stage air piston within said third stage air chamber and adapted to reciprocate therein;
• a second link connecting said second and third stage air pistons so that they reciprocate as a pair;
• and hydraulic means for moving said pair of first stage air pistons alternately with said pair of second and third stage air pistons so that air is forced through each of said air chambers and is compressed therein to above its initial pressure;
• wherein said hydraulic means includes:
• a swash plate hydraulic pump having at least four pumping cylinders located remotely from said block like housing and adapted to be driven by the turbine engine to produce a sequence of pulses of pressurized oil, and
• conduit means for transferring the pulses of pressurized oil from each of said remote pumping cylinders directly to and from a corresponding one of said air pistons within said block like housing to cause said pistons to reciprocate under the influence of hydraulic pressure.