Abstract: Apparatus and method for detecting leaks within underground or aboveground tanks and their associated piping whether the tank and/or piping is partially filled or empty. The apparatus is partially insulated to minimize temperature effects when injecting a test gas into the tank to be tested. The tank is pressurized to a fill pressure by injecting (bubbling) the test gas through any liquid in the tank. Once stabilized the pressure is reduced to a test pressure while the gas injection continues. The flow rate of gas into the tank is monitored by a flow meter able to measure small flows while the pressure is held constant by a pressure regulator having a high accuracy and the temperature of the ullage is monitored. A tight or leaking tank is determined by evaluating the flow rate of constant pressure against reference criteria which when met identify a tight tank and when not met identify a leaking tank under EPA guidelines.

Abstract: A volumetric leak detector. An overfilled storage tank has at its upper end a fill pipe predetermined surface area. An area converter reservoir is connected at this upper end with the storage tank, so that some liquid from the fill pipe flows into the reservoir. The area converter reservoir has a surface area which is larger than the surface area of the fill pipe. An almost constant minimum level is provided in the area converter reservoir, and the height difference between that minimal level and the actual level of the tank are as determined.

Abstract: Method and apparatus for detecting leaks in underground tanks containing a liquid. The pressure and temperature of the liquid are measured over a predetermining time interval, while simultaneously measuring the liquid level in the tank and the temperature of the liquid therein. From each measuring step the leak rate of the liquid from the tank is calculated and the two calculated leak rates are compared with each other. The temperature at a series of different depths in the tank is measured. Other measurements are made and fed to a suitable computer which computes the leakage rate.

Abstract: A transducer device and a system incorporating said transducer device useful, for example, for measuring a characteristic of particles in a particle flow stream. The transducer device comprises a front surface solid element in which an elastic wave is created, for example, on impact of a particle on an exposed front surface; a liquid medium; a thin piezoelectric sensing element; a solid back surface element; and a housing to hold the front and back surface elements in spaced relation with the liquid medium therebetween. Elastic waves created at the front surface are propagated through the piezoelectric element. The acoustic configuration of the transducer device is such that the electrical output signal of the thin piezoelectric is indicative of some characteristic of the first and the fastest pulse of the elastic wave.

Abstract: A projectile recovery system where projectile speed is progressively reduced as the projectile passes through decelerator tubes. These tubes are precharged to high pressure in front of the projectile to minimize the decelerating distance. Quick opening valves, which separate the deceleration tubes and which seal them for pressurization, are opened as the projectile approaches so they will not be struck by the projectile with resulting damage.