短语词组短语valve plate type piston pump 阀板式活塞泵;闸板式活塞泵valve box type piston pump 阀室式活塞泵;阀箱式活塞泵valve pot type piston pump 阀室式活塞泵;阀箱式活塞泵valve type piston pump coupling 阀形活塞泵联轴器 返回 valve type piston pump