Polish rod compression type casing air recycling and dosing device

The invention discloses a polish rod compression type casing air recycling and dosing device. The polish rod compression type casing air recycling and dosing device comprises an air collecting cylinder body mechanism, a dosing mechanism, a driving cylinder body mechanism and a pressure arm, wherein the upper end of the driving cylinder body mechanism is connected with a polish rod in a well mouth through the pressure arm, and the lower end of the driving cylinder body mechanism is fixed to a large flange of a well mouth four-way through a fixing mechanism; the air collecting cylinder body mechanism and the dosing mechanism both communicate with the driving cylinder body mechanism through pipelines correspondingly. On one hand, the device can be conveniently, safely and quickly installed on the ground, meanwhile, the polish rod compression type casing air recycling and dosing device has heat dissipation and lubrication functions, air collection is achieved, meanwhile, under-pressure dosing of an oil well casin