| http://www.w3.org/ns/prov#value | - An oil pump assembly having an adjustable production rate and capable of long stroke, low stroke per minute pumping rates, comprising a reciprocating pumping rod in a well hole, a counterbalancing mechanism for reducing the power needed to pump oil by the pumping rod, a driving mechanism to drive the reciprocating pumping rod and the counterbalancing mechanism, including a first cable and a second
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