Patent ID: 9341169
Filing Date: 2016-05-17
CPC Classification: F04B,F15B,G01S

Claim Text:
1. A method for determining a piston position in a positive displacement pump of a downhole tool, comprising: providing a transducer in the downhole tool, wherein the positive displacement pump has a piston used to create a vacuum for the downhole tool; contacting a surface of the piston with a fluid disposed within a fluid chamber of the positive displacement pump; providing a transducer tone burst of acoustic energy across the fluid chamber and toward the surface of the piston; reflecting the transducer tone burst by the surface of the piston; receiving the transducer tone burst at a receiver; calculating time of flight for the transducer tone burst; and determining the piston position in the positive displacement pump based upon the calculated time of flight of the transducer tone burst.