Patent ID: 7621179

Claim:
A diagnostic system for a check valve of a positive displacement pump having a solid-borne sound sensor, comprising: a calculating device configured to calculate a first operative sound level of a first value of a first operative sound signal recorded in a first state of the valve induced during operation of the pump and to determine a second operative sound level of a second value of a second operative sound signal recorded in a second state of the valve induced during operation of the pump, wherein the first sound value is determined based on a current sound signal recorded in the first state of the valve and the second sound value is determined based on a last sound signal recorded in the second state of the valve, the last sound signal being a half period delayed and stored; a determining device configured to determine a relevant state of the valve via an auto correlation; and a signal output that displays a fault if a deviation between the first sound level determined for the first state of the valve and the second sound level determined for the second state of the valve exceeds a pre-determinable threshold value, wherein the sensor measures solid borne sound and records the sound signals.