... 3)easy maintenance 4)long servicing API B series Pumping Units is conventional walking beam pumping units, ... Pumping Units” and other relative API standards, acquired the authorization to use Official API Monogram Technical Performances1,High ... herring-bone gearing, work smoothly and reliably.3,the complete machine with light weight, it’s convenient for ... -305,30030,2316,000 API B Series Pumping Units