ENSURING CONTINUOUS HYSTERESIS OF SPROAD ACTION VALVE SAFETY VALVES

Abstract

In the article principles of construction and design of spring valve units are considered, which allow to obtain a given dynamic quality to ensure constant hysteresis of spool safety valves of direct action. The analysis of efficiency of devices of correction of dynamic quality of spring valve units for ensuring their working capacity at variation of external operating factors by purposeful management of kinematic and force parameters of elastic-damping elements, and also the reasons influencing hysteresis It is noted that one of the reasons for the increase in hysteresis is damage to the rubber seals of the spool safety valves of direct action. Identifying the main causes of damage to rubber seals: constant friction of the edge of the radial holes of the spool on the seal ring; reverse the direction of the operating pressure; the pressure drop created by the axial hole of the spool when the valve is fully open. A spool spring valve with a mechanical spring having high throughput and low hysteresis is proposed. This characteristic was achieved through the use of high quality materials, which allowed to have a high throughput with minimal dimensions; optimization of geometrical characteristics of the flowing part of the valve; reducing the seal tension and, as a consequence, reducing the hysteresis. It is noted that the absence of contact of the radial holes of the spool with the rubber seal in the extreme off position protects the seal from plastic deformation during reverse flow. The prospect of further research in obtaining experimental dependences of the influence of spool speed, rubber stiffness, geometrical characteristics of the contact gap and pressure on the change of the valve hysteresis is revealed.