... BAOJI oilfield machinery co ltd , Sichuan honghua machinery co, ltd,Sichuan Kunlun petroleum equipment manufacturing co ltd ,ZYT petroleum equipment co ltdSichuan honghua petroleum equipment co., ltdF-500F ... mm. 1. In order to reduce the valve liquid in the valve box, Enlarge area of liquid circulating, make ... the pump valve increasing from API-5# to API-6#2. ...