Abstract: An apparatus for measuring liquid levels and leak rates in a storage tank, using an acoustic transducer and a quasi-static reference device that positions an acoustic target within a predetermined distance range below the surface of the liquid.

Abstract: The piston displacement apparatus and method for detection of leaks in pressurized pipelines disclosed herein measures volume changes at different pressures to determine thermally compensated leak rates. The apparatus uses a piston displacement apparatus to precisely determine volume changes.

Abstract: The gas pressure control apparatus and method for detection of leaks in pressurized pipelines disclosed herein measures thermally compensated leak rates. The apparatus uses a pressure vessel and gas pressure control system to precisely determine leak rates.

Abstract: The improved device for measuring liquid-level changes in storage tanks uses a float to track vertical displacement of the surface of a liquid and a linear variable differential transducer (LVDT) sensor positioned below the surface of the liquid to measure changes in the surface level. The center of gravity of the device is located below the center of buoyancy, thereby minimizing instability of the LVDT sensor.

Abstract: Methods for measuring liquid levels and leak rates in a storage tank, using an acoustic transducer and a quasi-static reference device that positions an acoustic target within a predetermined distance range below the surface of the liquid. A method for measuring the height of the surface of a liquid, i.e., liquid level.

Abstract: The positive-displacement pump apparatus and method for detection of leaks in pressurized pipelines disclosed herein measures volume changes at different pressures to determine thermally compensated leak rates. The apparatus uses a positive-displacement pump apparatus to precisely determine volume changes.

Abstract: A method of determining the presence and temperature compensated volumetric flow rate of leaks in fluid pressurized pipelines. The pipeline is maintained at a first pressure and the fluid volume change per unit time is calculated. The pressure is then maintained at a second different pressure and a second fluid volume change per unit time is calculated. The system is then maintained at the first pressure while a third fluid volume change per unit time is calculated. The first and third rates are combined with the second rate to obtain a temperature compensated leak volumetric flow rate.

Abstract: A tube vertically disposed in a liquid storage tank, in which the tube has a cross-sectional area which changes with height in proportion to the variation in the tank's cross-sectional area. The tube is filled through an open valve near the bottom of the tube and the valve is closed for the remainder of the test. Other valves above the liquid level are kept open to maintain equal vapor pressures in the tank and the tube. A first sensor measures the fluid level in the tank, while a second sensor measures the differences in fluid levels between tank and tube over a period of time. Ambient height changes are identical for liquid in both tank and tube, whereas leak related height changes occur only in the tank. A second identical tube may be provided when levels are affected by the tube or sensor, or when the tube is required to hold the sensor and is open to the tank.