Full automatic liquid-gas control workover crown block safety device

The utility model discloses a fully automatic hydraulic and pneumatic control well work over crown block security device, which belongs to a security device for the oil extraction well working over operation in the petroleum industry. The security device aims at disposing the problem that an idle car collides onto the crown block when a tubing string is raised up form a well or is dropped down to the well in the operation process of well working over. Under the circumstance without changing the original operating machine operation system, the device arranges two sensors respectively on the left side and the right side of a wheel hub of a roller for the operating machine, and enables the two sides to be connected with the two bidirectional pulse counting mechanisms arranged onto the two ends of the roller. The signal output terminals of the bidirectional pulse counting mechanisms are respectively connected with the signal input terminals of an alarming control cabinet arrange inside the operating room of the operating machine. The two signal output terminals of the alarming control cabinet are respectively connected with an electric control air valve and a solenoid directional control valve. The electric control air valve is arranged before the original double though air valve switch. A hole is drilled on the upper top bar of the original hydraulic augmenter, and the outlet is provided the solenoid directional control valve and an oil bath so as to form an outlet oil line. The utility model has the advantages of simple structure, reliable safety, high automatic level and high economic benefits as well as high value of generalization and application.