Line leak test apparatus measuring rate of pressure change in a liquid storage and dispensing system
First Claim
1. A line leak test probe for use in a liquid storage and dispensing system, said probe comprising:
- pressure transducer means for providing a pressure signal representative of the pressure in a liquid conduit;
timing means for providing a timing signal; and
leak test means responsive to said pressure signal and said timing signal to establish an initial pressure and compare said initial pressure against a current pressure to establish a pressure rate of change and said initial pressure is compared against predetermined pressure values over a period of time to determine if said system is leaking wherein;
said leak test means comprises first test means for leak testing said system over a first time period and second test means for leak testing said system over a second time period that is longer than said first time period.
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Abstract
A line leak test probe for use on a liquid conduit. A pressure transducer is mounted in mechanical contact with the liquid in the conduit and a temperature transducer is mounted in thermal contact with the liquid. The transducers provide signals to a microprocessor-based circuit which includes a timer. Software stored in the microprocessor analyzes the time rate of change of the pressure to determine if there is a leak. Normally a sequence of three tests are performed: a catastrophic test, a gross test, and a precision test. The catastrophic test exits to the gross test if the rate of change of the pressure is less than a first rate, and the gross test exits to the precision test if the rate of change is less than a second rate which is less than the first rate. The precision test normally cycles until the pressure drops below 4 psi, and then outputs a leak signal if the pressure drops to below 3 psi in 12 minutes or less. If the temperature change during the test is sufficient to account for the pressure change, or the temperature is out of a range where it can be measured, the test aborts without outputting a leak signal.
79 Citations
14 Claims
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1. A line leak test probe for use in a liquid storage and dispensing system, said probe comprising:
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pressure transducer means for providing a pressure signal representative of the pressure in a liquid conduit; timing means for providing a timing signal; and leak test means responsive to said pressure signal and said timing signal to establish an initial pressure and compare said initial pressure against a current pressure to establish a pressure rate of change and said initial pressure is compared against predetermined pressure values over a period of time to determine if said system is leaking wherein; said leak test means comprises first test means for leak testing said system over a first time period and second test means for leak testing said system over a second time period that is longer than said first time period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification