Relief valve

In an aircraft engine and cabin pressurization system, a pressure relief valve for limiting the compressor discharge pressure to a predetermined maximum value, comprising:

• a. a venturi disposed along a compressor discharge first flow path coupled to the cabin pressurization system
• b. a diaphragm;
• c. a housing cooperating with said diaphragm for defining a chamber;
• d. means for communicating throat pressure from the venturi to the chamber;
• e. a valve member movable with said diaphragm;
• f. means defining a relief port adjacent said valve member for communicating the compressor discharge pressure in a second flow path to said valve member and to said engine so that said diaphragm and valve member respond to the differential between compressor discharge pressure in said second flow path and venturi throat pressure;
• and
• g. spring means for biasing said valve member to close said port until the pressure differential across said diaphragm and valve member exceeds a predetermined value.

A method of limiting the discharge pressure of a compressor to a predetermined value, comprising the steps of:

• a. providing pressure differential responsive valve means for relieving compressor discharge pressure when the pressure differential exceeds a predetermined value;
• b. communicating the compressor discharge pressure in a first flowpath to one side of said valve means and to a first point of use;
• c. passing the compressor discharge through a venturi formed along a compressor discharge pressure second flow path to a second point of use;
• and
• d. communicating the venturi throat pressure with the other side of said valve means so that said means responds to the differential between compressor discharge pressure and venturi throat pressure to relieve compressor discharge pressure.

In an aircraft engine and cabin pressurization system, a method of limiting the compressor discharge pressure to a predetermined maximum value, comprising the steps of:

• a. providing a venturi disposed along a compressor discharge first flow path coupled to the cabin pressurization system
• b. providing a diaphragm and a housing cooperating to form a diaphragm chamber;
• c. communicating throat pressure from the venturi to the chamber;
• d. providing a valve member movable with the diaphragm;
• e. communicating the compressor discharge pressure in a second flow path to said engine and via a relief port in said second flow path to the valve member and thereby to the other side of the diaphragm so that the diaphragm and valve member respond to the differential between compressor discharge pressure in said second flow path and venturi throat pressure;
• and
• f. biasing the valve member to close the port until the pressure differential across the diaphragm and valve member exceeds a predetermined value.

A pressure relief valve for limiting the compressor discharge pressure to a predetermined value, for use in an aircraft engine and cabin pressurization system comprising:

• a. pressure differential responsive means for relieving compressor discharge pressure when the pressure differential exceeds a predetermined value;
• b. first means for forming a first flow path communicating the compressor discharge pressure to one side of said pressure differential responsive means and to a first point of use;
• c. second means for forming a second flow path for compressor discharge pressure to a second point of use and including a venturi along the second flow path;
• and
• d. third means for communicating throat pressure from the venturi to the other side of said pressure differential responsive means so that said pressure differential responsive means responds to the differential between compressor discharge pressure and venturi throat pressure to relieve compressor discharge pressure.