井下工具拆装架主钳转矩测量方法及误差分析

Analysis of Torque Measurement Error and Method of Major Power Tongs for Downhole Tool Hydraulic Torque Equipment

液压拆装架用于井下工具螺纹的上紧和卸扣,转矩的测量和控制是通过主钳来完成。力臂式主钳是由液缸推动传力杆产生转矩,力臂的长度随转角而变,实际测量转矩时是取定长力臂进行计算,因此误差较大。齿轮齿条式主钳是由液缸推动齿条,齿条带动拧扣大齿轮产生转矩,力臂是拧扣大齿轮的节园半径,因此转矩测量误差仅与仪表精度有关。齿轮齿条式主钳实现了转矩的实时测量和控制,测量精度高。

The downhole tools to making-up and breakout using hydraulic device and torque meas- urement and control are implemented with main tong. Force arm tong is driven by hydraulic torque, with the length of force arm changing with turning angle. The calculation of the force arm is done by using actual measuremem of torque,which produces error. The gear rack is pushed by hydraulic cylinder in type of gear wheel and gear wheel tong. The torque is built when gear rack driving gear wheel. The force to turn gear wheel is by wheel radius,so the measurement error by the torque is something related to the instrument precision. The new type of gear wheel and rack tong gives real-time measure and control,and the accurate measurement is obtained.