Patent Document ID: 20090187356
Application ID: 12347860
Patent Flag: 0

Claim One:
1. A system for continuously monitoring performance of a rotary-type gas flow meter, the system comprising: a pressure sensor module for measuring a differential pressure in a rotary-type gas flow meter that includes a volume output port to output a gas volume signal indicative of a volume of a gas that flows through the meter in response to the gas flowing from an inlet of the meter to an outlet of the meter, the pressure sensor module comprising a first input port to be put in fluid communication with the inlet of the meter, a second input port to be put in fluid communication with the outlet of the meter, and an output configured to generate a differential pressure (dP) signal indicative of a measured differential pressure across the meter based on a difference between a gas pressure at the first input port and a gas pressure at the second input port; a processor module configured to receive and process the gas volume signal, the dP signal, and at least one additional parameter measured in the meter to diagnose a status of the meter; a data store storing a first set of instructions that, when executed by the processor, cause the processor module to perform a first set of operations to develop a first baseline dP characteristic over a first period of time, development of the first baseline dP characteristic being based upon the dP signal, the at least one additional parameter, and the gas volume signal over the first period of time, the first set of operations comprising: a) store values corresponding to the gas volume signal, the dP signal, and the at least one additional parameter measured during the first period; b) apply a predetermined functional relationship to the values stored in step a) to calculate a coefficient; c) update a set of coefficient values that define the first baseline dP characteristic based on the calculated coefficient; and, d) repeat steps a)-c) during the first period to develop the first baseline dP characteristic; and, a data store storing a second set of instructions that, when executed by the processor, cause the processor module to perform a second set of operations to develop a second baseline dP characteristic over a second period of time, development of the second baseline dP characteristic being based upon the first baseline dP characteristic, the dP signal, the at least one additional parameter, and the gas volume signal over the second period of time, wherein the second period of time is substantially longer than the first period of time, the second set of operations comprising: e) store values corresponding to the gas volume signal, the dP signal, and at least one additional parameter measured during the second period; f) apply a predetermined functional relationship to the values stored in step e) to calculate a coefficient; g) update a set of coefficient values that define the second baseline dP characteristic based on the calculate coefficient; and, h) repeat steps e)-g) during the second period to develop the second baseline dP characteristic; and, i) calculate an expected dP value by applying the predetermined functional relationship from step b) to the values corresponding to the gas volume signal and the at least one additional parameter stored in step e) and to a coefficient of the first baseline dP characteristic that corresponds to the values stored in step e); j) compare the dP signal stored in step e) to the expected dP value calculated in step i); and, k) generate an electronic notification signal upon determining that the dP signal exceeds the calculated expected dP value by more than a predetermined amount.