Method and apparatus for detecting leaks in the ullage of a liquid storage tank
US5295391A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 11, 1992 |
| Grant date | Mar 22, 1994 |
| Priority date | — |
| Expiry date | Feb 11, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01M3/3254
- WIPO fieldMeasurement
- WIPO sectorInstruments
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. Temperature, deflection, and other effects on leak rate detection are compensated for by prescribing waiting periods, filling times, and multiple and repeat threshold exceedance criteria. Flow rate, temperature and pressure can be reached manually or fed to a suit…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.