Sucker-rod pump plant operation is accompanied by inertial and shock loads, affecting the fatigue strength of sucker rods, and causing possible accidents. Sucker-rod string protection from extra load will increase the sucker-rod pump plant efficiency and save on additional costs in general. This work proposes the original design of a shock absorber of a sucker rod string. The peculiarity of the proposed design is usage of annular thin plate packages as a bearing elastic element of the shock absorber. This approach to the elastic element’ design provides the shock absorber to be easy to manufacture and operate.

We construct a mechanical model of the working link as the package of two annular thin plates without cross-links and friction between the plates. Each of them is deformed as the separate plate, which has its own neutral surface. The load on the package of plates is distributed between the plates in proportion to their stiffness in bending. The shock absorber can have packages of plates with different rigidity. They are installed with the possibility to exclude from the work of separate packages of plates during overloads. This fact expands the range of operating loads for which the elastic suspension can effectively perform its functions.

Let's describes the operation of the packages of annular thin plates as elastic elements for shock absorbers of sucker rod strings. When the sucker rod string moves, the lower and upper traverses load the elastic member (Fig.1). In this case, the shock absorber gets certain submersion, what is determined by deflection of one package, which is increased on times, where  is total number of plate packages. Note the useful length of the plunger stroke is reduced by the amount of submersion of the shock absorber and this fact must be taken into account at the design stage.

Consequently, during loading of the shock absorber its working links (there are plate packages) change their shape and accumulate the potential energy of elastic deformation. When the axial load is reduced, the moving parts of the elastic suspension are returned to the original position due to the energy accumulated by the plates. The gaps between the plate packages are designed so that at overload the plate is excluded from the work. Thus, at the certain shock absorber characteristic the nature of application and the value of maximum and minimum forces acting on the sucker rod string are varied, the effect of the vibrational, inertial and shock loads are reduced.

The flexibility of the elastic suspension can be easily adjusted, to change the number of working links in the elastic element, or to vary the thickness of the plate package. To extend the load range at which the device works efficiently, the working links of different thicknesses can be used, and if it is necessary for increasing the working capacity of the elastic suspension, it is a constructive possibility to include the working links in parallel operation.

Thus, presented herein work proposes a new design of the plate shock absorber of the sucker rod string. The proposed design’s peculiarity is the annular thin plate package usage as the main bearing element of the device.