Patent ID: 8281866

Claim:
A tubing drain valve for incorporation between a production tubing string and a pump, the tubing drain valve comprising: a housing having an uphole end for connection to the production tubing string above the pump and a downhole end for connection to the pump, downhole of the housing, the housing having a valve bore in communication with fluid in the tubing string and the pump; one or more drain ports in the housing communicating with the valve bore; a sleeve fit to the valve bore and being axially moveable in a reciprocating action in the valve bore, the sleeve having a central bore therethrough; a first check valve positioned downhole of the sleeve for sealing the central bore at a downhole end of the sleeve for forming a downhole piston face, fluid from the pump acting thereat to lift the sleeve uphole to block the one or more drain ports in a production position; and unsealing from the central bore for permitting fluid to flow therethrough in the production position; a second check valve positioned above the sleeve for unsealing from the central bore at an uphole end of the sleeve for permitting fluid to flow therethrough in the production position; and sealing the central bore for forming an uphole piston face, fluid in the production tubing string thereabove acting thereat to move the sleeve downhole to open the one or more drain ports in a drain position for draining fluid from the production tubing string therethrough.