Study On Mechanical And Wear Behavior Of Stator Rubber Swelling With Cyclohexane Mixture

With the widespread use of screw pumps in oil extraction engineering,the life and performance of rubber stators have received increasing attention.When the rubber stator is working,it is continuously squeezed by the metal rotor,and is also affected by complicated working conditions such as high temperature,high pressure,corrosive liquid gas and high sand content.The rubber performance and wear resistance are reduced,which affects the life of the entire screw pump system.During operation of the screw pump,the rubber stator is continuously squeezed(stretched and compressed)and rebounded.The multiple effects of stretching and compression will cause changes in the structure of the rubber,which in turn affects its performance.At present,little attention has been paid to the effect of stretching on the swelling and aging of rubber in liquid media,and this will provide theoretical support for the swelling and aging of the stator rubber by the liquid medium during the friction operation.In addition,the wear of the stator rubber is related to the service life and reliability of the screw pump.Many literatures have reported the friction and wear of rubber seals in corrosive liquid media.Although the corrosive liquid media has been accelerated to accelerate rubber wear,the interaction between the two has not been studied in depth.To this end,this paper selects the common rubber of the two kinds of screw pumps of nitrile rubber(NBR)and fluororubber(FPM)as the research object,and uses the mixed solution of cyclohexane and base oil as the medium to make the pre-stretching of the rubber.The fixture device is extended to analyze the effect of stretching on the swelling aging and mechanical properties of the rubber in the solution medium.Based on the swelling test,the friction and wear tests were carried out to find out the relationship between the concentration of cyclohexane,the load and the wear of the stator rubber.The mechanism of rubber wear after swelling and aging was analyzed,focusing on the interaction between swelling and wear.Gives the action mechanism of cyclohexane on the wear of stator rubber.Through the study of the above problems,some main conclusions are obtained: the mass increase of the swollen nitrile rubber is higher than that of the fluororubber,and the performance in terms of hardness and elastic modulus is lower than that of the fluororubber.After the pre-stretched rubber swells and breaks,the tensile strength of the tensile specimen of nitrile rubber shows an upward trend,the value is lower than that of fluororubber,and the elongation at break shows a downward trend.The value is higher than that of fluororubber.The trend of performance changes is the same.The wear and friction coefficients of the two rubbers increased during wear and increased with the increase of load and cyclohexane concentration.The wear surface of nitrile rubber under the same conditions was more serious than that of fluororubber.The research of this subject will provide a theoretical basis for the selection of the rubber pump of the screw pump working in corrosive liquid environment,and it has practical significance for the improvement of the service life of liquid conveying equipment such as submersible screw pump and other working under this condition.At the same time,it will help the improvement and development of the theory of rubber tribology.