Bleeding air regulator control pneumatic circuit, leakage detection system for testing a device under test, and method of testing for leaks in a device under test
The present invention is a bleeding air regulator control pneumatic circuit for supplying air to a leakage detection system for testing a device under test for leakage. The bleeding air regulator control pneumatic circuit includes an air supply source having an outlet port for supplying compressed air to the leakage detection system; an air relay having a first port in fluid communication with the outlet port of the air supply source and a second port in fluid communication with an inlet of the leakage detection system; a pressure regulator having an inlet port in fluid communication with and connected at a point between the outlet port of the air supply source and the first port of the air relay, and an outlet port in fluid communication with and connected to a third port of the air relay; a bleed valve having a first port in fluid communication with a fourth port of the air relay and a second bleed port; and a flow control valve positioned between and in fluid communication with the air relay and the bleed valve.
1. A method of testing for leaks in a device under test by measuring the rate of leakage of a gas from the device under test, said method of testing for leaks comprising the steps of:
a. filling the device under test by:
i. opening a fill valve having a first port in fluid communication with a second port of an air relay, and a second port in fluid communication with the device under test;
ii. opening a bleed valve having a first port in fluid communication with a fourth port of the air relay; and
iii. filling the device under test slightly above a final setpoint pressure for a programmed period of time with air from an air supply source having an outlet port for supplying compressed air to the device through the air relay and fill valve;
b. stabilizing the device under test by:
i. closing the bleed valve and slightly lowering the air pressure delivered to the device under test through the air relay;
ii. opening a test valve having a first port in fluid communication with the second port of the air relay, and a second port in fluid communication with the device under test which allows an alternative flow path through a mass flow sensor in fluid communication with and positioned between the test valve and the second port of the air relay;
c. testing the device under test by:
i. closing the fill valve while the test valve remains open such that all test air is being delivered through the test valve and the mass flow sensor for a programmed period of time;
ii. measuring the air flow through the mass flow sensor to maintain the setpoint pressure; and
iii. determining the leakage by measuring the air flow;
d. venting the device under test by:
i. closing the test valve; and
ii. opening a vent valve having a first port in fluid communication with the device under test and a second port open to a vent to the surrounding atmosphere allowing the device under test to vent to atmospheric pressure for a programmed period of time.
2. The method of testing for leaks in a device under test according to claim 1 , wherein step of opening a bleed valve further comprises the step of opening a flow control valve positioned between and in fluid communication with the air relay and the bleed valve.
3. The method of testing for leaks in a device according to claim 2 , wherein the step of opening a bleed valve further comprises opening the flow control valve positioned between and in fluid communication with the air relay and the bleed valve to a desired flow rate.
4. The method of testing for leaks in a device according to claim 3 , wherein the bleed valve is normally open.