Patent ID: 8366402

Claim:
A method, comprising: monitoring a pump chamber pressure in a pump chamber of a positive displacement pump; detecting a plunger position within the pump chamber of the positive displacement pump; determining at least one of a suction lag corresponding to a suction valve and a discharge lag corresponding to a discharge valve; measuring a discharge pressure of the positive displacement pump; determining the at least one of the suction lag in response to at least one of D 1 and A 1 , wherein D 1 reflects a time difference between an event marking the detection of a bottom-dead-center plunger position and a subsequent event marking the pump chamber pressure being equal to at least one-half of the discharge pressure, and wherein A 1 reflects a time difference between the event marking the detection of a bottom-dead-center plunger position and another event marking the detection of closing the suction valve; outputting at least one of the suction lag and the discharge lag to a control system and accumulating data relating to said pump chamber pressure, said plunger position, and said at least one of the suction lag and the discharge lag over consecutive operations of the positive displacement pump; and, running a regression program on said accumulated data to provide an estimated time to failure for one of the suction valve and the discharge valve.