US Patent 10053936 Thermal compensating tubing anchor for a pumpjack well

Apparatus and method for limiting the expansion and contraction of a production tubular within a pumpjack oil well includes an anchor having a hydraulic dampening chamber and an expansion joint. A piston is attached to the tubular and position within the hydraulic dampening chamber so that axial expansion and contraction of the tubular caused by thermal and loading forces is resisted by the constrained movement of the piston within the hydraulic chamber.