The Research And Development Of Octg Thread Atomatic Measuring Instrument

Oil tubular goods, which include OCTG and oil & gas transmission pipe, has an important role in the petroleum industries. OCTG thread connection is the weakest part of OCTG. The low quality of thread connection will lead to failure accident, such as breakout, leak, thread gluing etc., even malignant accident, and cause great economic loss and serious consequence. The qualities and properties of OCTG thread connection have been related with the safety reliability and serviceable life of oil and gas well. Enhancing quality control of OCTG thread connection has great engineering signification.Based on the current situation and development trend of OCTG thread measuring technique, the paper combines the advanced computer control technique with three-dimensional scanning, and presents a new system of automatic OCTG thread measuring.The paper describes the control theory and system of automatic OCTG thread measuring instrument, and investigates deeply multi-axis motion controller which adopted the advanced DSP as its core, and control system, and built the opening digital control system "PC + motion controller". The paper describes the basic control arithmetic of the probe-point position detect in detail. On the foundation of it, the continuous scan control arithmetic has been studied, and the OCTG thread measurement is solved successfully.The paper built the arithmetical module and evaluation method of OCTG thread measurement, and achieves the automatic measurement and evaluation of thread diameter, taper, pitch, and carries out the assessment and verification of measurement uncertainty according to the " Guide of evaluation for measurement uncertainty" . Abundant experimental data is well applied to the relation between thread standoff and diameter measurement, and the necessities of direct measurement of thread parameter such as diameter are illustrated in this paper.To the traceability of the measurement and calibration of OCTG premium connection, the study has very important referenced value.