Beveridge, DeGrandi, Weilacher & Young
Chain long-stroke oil-well pumping unit
 The invention relates to oil recovery equipment improved from existing chain oil-well pumping units. Double suspending cables, double balance flexible cables and a counterweight structure without inertial load are used in the invention. There are guide buffer devices and a buffer eccentric regulation shaft coupling in the apparatus according to the invention. Consequently, the load distribution and the stressed condition are more reasonable, the structure is simplified and reliable, and power is obviously economized. The invention has the striking strong points mentioned above in recovering condensed oil, high-condensed oil and bathhypelagic oil. 
Oil Production Technology Institute
E F
E21B F04B
inventional inventional
Chaoying Guanggi Xinhua Juanhuan Kaili Quingkun
Shi Gao Li Yang Song Zeng