Title
Well-head polish-rod sealer capable of regulating bias
Application Number
200620113028
Publication Number
2895715
Application Date
April 21, 2006
Publication Date
May 2, 2007
Inventor
Liu Defa
Lu Keqin
Guo Shengli
Liu Ruixian
Zhang Xuechen
Ge Shaojun
Agent
liyu meng
Assignee
China Petroleum &Amp Natural Gas
IPC
E21B 33/03