| 摘要 |
<p>"OIL WELL DOWNHOLE PUMP" In an oilfield downhole reciprocating pump having a plunger, travelling valve, and standing valve, a urethane seal ring is mounted in each of the plunger surface, travelling valve ring seat surface, and standing valve ring seat surface, to protrude outwardly therefrom and provide the seal with the adjacent surface of the barrel, standing valve ball, and seal ring member respectively.</p> |
