A leak detection system for detecting the leakage of fluids from storage tanks uses a reference container, such as a standpipe, having its bottom adjacent the level of the bottom of the tank, which is initialized to the same hydrostatic head pressure as the tank, and then closed off. The differential pressure between the hydrostatic head pressures of the standpipe and the tank is monitored over time in an externally mounted differential pressure gauge in order to detect the leakage of fluid from the storage tank. Shut off of valves are provided in a tank pressure pipe and a reference pressure pipe to isolate both sides of the differential pressure gauge. The very high sensitivity of available differential pressure gauges allows the detection of very small leaks and very low leakage rates. A leak detection system of unitary construction may be provided in which the standpipe is provided with an equalizing valve so that the system may be installed through a single hole in the top of a liquid storage tank. In alternate embodiments the standpipe is mounted internally and external to the tank and in an external extension of the tank. In another embodiment a vacuum system is used to draw fluid equally through the differential pressure gauge from both the tank and the standpipe to develop equal negative pressures on each side of the gauge.

Leak detection system for storage tanks

An apparatus for detecting a change in the amount of liquid in a storage tank. The apparatus comprises a vertical upright standpipe for filling with a liquid to a level that generates a hydrostatic head pressure substantially equivalent to that exerted by the liquid in the storage tank; a sensor for sensing hydrostatic head pressure differential between the liquid in the storage tank and the liquid in the standpipe; a connector for connecting the standpipe to the pressure differential sensor, the standpipe connector being substantially horizontally disposed to the standpipe; and a connector for connecting the storage tank to the pressure differential sensor, the storage tank connector being substantially horizontally disposed to the storage wherein the standpipe connector and the tank connector are in substantial axial alignment with each other. Any change in the liquid pressure in the tank as a result of leakage from the tank will change the differential pressure measured by the pressure transducer. The apparatus is particularly useful in the detection of leaks from storage tanks containing highly volatile liquids, such as gasoline.

Above-ground storage tank liquid leak detector

An expansion gap radiation shield is formed from a flexible container housing a radiation shielding fluid, that is located within a variable gap in permanent shielding. The invention reduces radiation dose rates outside the gap when the radiation sources are located on the opposite side of the gap. The device accommodates varying gap sizes with no loss of shielding capability.

Zhugan Lidiya I

Papers

Hydrostatic level indicator