A Study On The Rational Interference Fit Between Rotor And Stator Of Progressing Cavity Pump

A Study on the rational interference fit between rotor and stator of progressing cavity pump has been carried out by rational design of initial interference fit,thermal expansion amount and swelling value and other interference fit. On the basis of mastering the physical properties of the stator, especially mastering the thermal expansion and swelling behavior. The related methods include adjusting one or more parameters and to ensure the value of interference fit to keep in a rational arrange that can get steady load characteristic of progressing cavity pump and realize low energy consumption and long life on the premise of effective displacement and lifting capacity.The rotor's characteristics of motion in the bush of stator and the influence on the interference fit by the shaped conductor's variation have been analyzed and discussed in three aspects of the structural mechanics,thermodynamics and hydromechanics. The results show that the interference contact force on the potted line can be reduced by diminishing section diameter of rotor or eccentricity of rotor respectively. The reduction of diameter of section circle of rotor can diminish maximum interference contact force rapidly and the reduction of eccentricity of rotor can make even sealing ability on the potted line. Considering thermal expansion and swelling of stator rubber under the actual conditions, the method of modifying section diameter of rotor and eccentricity is applied to assure sealing ability and to reduce friction torque between rotor and stator of progressing cavity pump.It is confirmed that the matching of imported rubber is better than home-made rubber by the comparative analysis between them and by the analysis of domestic rubber's medium resistance. Due to rigorous and complex working conditions such as high temperature,high pressure and saline and alkali oil and gas in the oil well, the application of rubber in different block should fully consider the service performance of different hardness in different working condition. In order to satisfy actual conditions, comprehensive evaluation has been produced to specific medium resistance, and simulation has been made under to the condition and medium of the down hole. The application effect can be influenced by the characteristics of rubber under working condition; therefore the application characteristic of progressing cavity pump is sure to be affected. The working conditions should be considered sufficiently during evaluating the performance of different rubber.The method of adjusting rotor's diameter and eccentricity has been produced in this article. The heterogeneity of the rubber's expansion has been fully considered and the matching status between the rotor and the stator has been improved, which enhance the working performance of progressing cavity pump.