Design of an auto-rotational centralizer based on the liquid hydrodynamic lubrication structure

With the increasing problems about eccentric wear of the pumping rod and tube getting more and more intensely, the study on the mechanical properties of the rod’s up and down stroke has been took, and a new type of centralizer preventing the eccentric wear between the rod and tub has been designed. The centralizer consists of centralizer shaft, centralizer cover, coupling, spring washer and positioning block. Depending on the dynamic pressure lubrication effect and the rotating of the centralizer cover by itself, this equipment transfers the dry friction, boundary friction and the sides wear into the boundary friction, liquid friction and the uniform wear between the rod and the tube. And then the service lifespan of the sucker rod increased greatly. The performance of centralizer was tested by applied to self-designed pumping system, and the results show that the hydrodynamic lubrication film will form when the motor speed reaches up to 75 rounds per minutes, and the eccentric wear of the pumping rod and tube is alleviated significantly. The technology will increases the service lifespan of sucker rod and tube and also expands the guarantee period of the well, which provide a technological support for oilfield’s anti-eccentrically worn investigation.