Device and process for controlling the pressure and delivery of a fuel feed to a servovalve unit

In a fuel supply circuit of an aircraft engine including fuel injectors and a plurality of servovalves, a low pressure pump for raising the pressure of fuel from a tank from a pressure Pca to a pressure Pb, and a high pressure pump and filter for further raising the pressure of the fuel to a pressure Psf at the outlet of said filter, a device for controlling the pressure and delivery of fuel to said plurality of servovalves comprising:

• a compartment divided in a sealed manner to define a first end chamber, an intermediate chamber, and a second end chamber;
• a spool movable in said compartment and having first and second end portions and an intermediate portion;
• said first end portion being engaged in a sealed manner in said first end chamber;
• said intermediate portion including a piston dividing said intermediate chamber in a fluid tight manner into first and second half-chambers;
• means for communicating said first end chamber with fuel at the pressure Pca;
• means for communicating said second end chamber with fuel at the pressure Pb;
• a first outlet port in said intermediate chamber in communication with fuel at said pressure Pb;
• resilient means disposed in said first half-chamber and acting to urge said spool in the direction of said second end chamber;
• diaphragm means having an inlet and an outlet;
• said inlet being connected to receive fuel at the pressure Psf and also being connected to said first half-chamber;
• said outlet being connected to a fuel feed line to said servovalves and also being connected to said second half-chamber;
• said spool being movable in said compartment in response to forces exerted on said spool by said resilient means and the fuel pressures applied to said first and second end chambers and to said first and second half-chambers to cause said piston to vary the opening of said first outlet port.