Patent ID: 8061184

Claim:
A method of monitoring or detecting small gas or liquid leaks in a gas or liquid supply system comprising a pipe and having a pilot light comprising: i) at a time when the system is leak-free, undertaking a valve open-valve closed test to determine whether there is a flow in the pipe other than due to the pilot light; ii) if there is no flow in the pipe other than due to the pilot light, obtaining a signature of the flow in the pipe due to the pilot light by closing the valve in the supply line for a period short enough not to extinguish the pilot light, opening the valve and measuring the fluid flow signature due to the pilot light; iii) storing the signature of the flow due to the pilot light in memory; iv) later when it is desired to test for leaks, conducting a valve open-valve closed test to determine whether there is a flow in the pipe other than due to the pilot light; v) if there is no flow in the pipe other than due to the pilot light, obtaining a measurement of the flow in the pipe by closing the valve in the supply line for a period short enough not to extinguish the pilot light, and then opening the valve and measuring the fluid flow; vi) comparing the measured flow to the stored pilot signature flow to determine if a leak exists.