Relevance. Analysis of technical means and methods of controlling sand entry allows supposing the presence of significant reserves to improve their effectiveness. In particular, it was found that most methods of reducing the influence of mechanical impurities on performance of pumping equipment currently or do not solve the problem fundamentally, or do not have a long-term nature. Hydrodynamic cleaning of submersible equipment, despite its efficiency, is impossible without tripping. The alternative to this method is the device of the valve type. However, their application is constrained because of the unsolved issue of selection of optimal design parameters of these devices. In this relation, there is a need for appropriate theoretical research. The main aim of the research is to carry out a system analysis and to propose a hypothesis of physical pattern of well submersible equipment purification using the upgraded backpressure valve. Methods: systematic analysis of well submersible equipment purification. Results. System analysis of operation of valve-type water treatment plants shows that the parameters of a special purification equipment have the largest number of relations among all the elements of the internal structure. Therefore, further study of the system is related to selection of corresponding subsystem, which determines only purification as well as to determination of this process physical pattern. The authors have proposed the hypothesis of purification physical nature. Taking into account this pattern, you can notice that the main aim of the entire system  is implemented in the subsystem «Operating conditions – constructive and technological parameters of valve performance». Identification of this subsystem allowed in general determining the relationship between purification performance and the main elements of the internal structure of this process. Practical use of the found interrelations is in possibility of informed search for optimal design parameters of the valve type device and purification flow rate through it, depending on the main factors.