The Technical Exploration Of The Cold Drawing Of The Rotator Of Progressing Cavity Pump

Progressing cavity pump lifting technique was developed in 1980s last century. As a new drilling oil equipment, it is smaller, lighter, simpler, and more efficient in energy-saving than beam pumping well. This equipment is suitable for drilling oil in sticky oil field and can efficiently overcome sand and air problem. So it has unique advantage than other oil drilling equipment and can replace heavy pumping unit in recent years.This type of pump transfers fluid by means of the progress, through the pump, of a sequence of small, fixed shape, discrete cavities, as its rotors turned.It has relatively high requirements for machining and assembly. Until now, it is commonly made by shaping cutting and shaping milling, but this way of manufacturing screw is based on the shape of cutting or milling tools and it is very difficult to make this kind of tools, so it has poor efficiency in production. Moreover it is hard to satisfy the straightness of the pump screw. The ideal way of solving this problem is stretching the screw to satisfy the straightness.The screw of this pump is usually made by alloy steel. For the purpose of improving efficiency, the hardness of the surface of the screw is not high.The common way of improving the surface hardness is nitridation process. As the hardness of the essential material is relatively low, the result of the method is not good. If we can stretch the screw in cold condition, the mechanical property and surface hardness can be efficiently improved. Based on the two points, we try to design a new screw stretching machine to improve the abrasion resistance and the life span of the pump.In the procedure of the cold drawing of this rotator, we have deduced the expression of relationship of diameter and length changing, in the case of the reduction of the coordinated precision. For the purpose of drawing the rotator, we need two fluid cylinders to afford huge tensile strength. We have built the mathematic model of the two fluid cylinders and established the controlling parameters in order to ensure the synchronization of the two cylinders. We also have built the finite element model of the draw frame, which could guarantee the reliability of precision in our designing.Around the idea of the issues arising by this method, the article has made a detailed discussion.1) I have conceived a new type of rotor stretcher.2) This article has fitted a formula based on an experiment. We could forecast the law of diameter's changement of the slender rod which is in the state of yield.3) This article has conceived a solution of cylinder synchronization, and has built a module of this system. According to this module, we have deduced the parameters of the regulated time and Maximum error.4) With the software of ANSYS, we have calculated the stress and deformation of components of this stretcher.