Abstract: A method of, and apparatus for, determining leakage in a valve or the like which is not dependent on bulk modulus of the fluid is described. The test apparatus includes a pressure transducer which measures the change in pressure along a length of pipe (XY) from the valve under test to a second valve for a period of time. The effect of bulk modulus of the test fluid is eliminated by placing a volume of gas between the pressure transducer and the section XY of pipe. Leakage is determined by measuring the change in pressure at the transducer over a period of time after the valve under test is closed.

Abstract: A leakage detection system and method for measuring pressure leaks from pressure vessels, containers, or the like which hold or exclude fluids. A sealed test fixture or bell jar surrounds the container or part under test and is connected to a reference pressurized reservoir. A reference bias flow is introduced into the bell jar to establish a "floor" or offset wherein any deviation measured from introduced bias flow indicates an anomaly. The test part is pressurized. The flow between the bell jar and the reference pressurized reservoir is measured by a mass flow leak sensor. The measured flow is used to determine the leakage of the test part by taking into account the previously introduced reference bias flow. The present invention provides accurate measurement of leaks having low flow rates occurring over short periods of time.

Abstract: A leak detector calibration device for generating a leak standard and for calibrating leak detecting instruments. The leak detector calibration device includes a flow control valve, a transducer, an amplifier module, and a display module, all operating from a 9 volt supply. This configuration is a compact, hand-held instrument for use in a manufacturing environment. The device is highly accurate and uses a mass flow sensor sensitive to measurement of low flow rates. The need for fragile glass orifices or clumsy soap film flowmeters present used to calibrate leak detecting instruments is eliminated. In addition, the device can be used not only to generate a leak standard to calibrate positive flow leak detectors, but can also be used to generate a leak standard for negative flow or vacuum type leak detectors.

Abstract: A fluid flow sensing apparatus for measuring very low fluid flows comprising a fluid mass flow sensor for measuring the mass flow rate of a fluid from a temperature differential between predefined points within the sensor; a fluid flow channeling element for accepting the fluid at an input temperature and pressure and directing the fluid across the sensor, and wherein the input temperature and pressure about the sensor is maintained; and a fluid flow dampening element for providing an average fluid flow to the sensor.