CALCULATION OF SEALING PRESSURES OF SHUT-OFF VALVES

The proposed algorithm for calculating the sealing pressures of the shut-off valve allows one to take into account the structural features of its parts and their elements that affect the amount of sealing pressures.  These parts are divided into fastening system and sealing system. Analytical dependencies for determining the forces acting in these systems allow us to determine the force values when fastening components are tightened, during pressure rise and release, and also when exposed to temperatures. When calculating the specific structure of the shut-off valve, it is shown that the forces in its sealing system and fastening system exceed the values determined by known methods of calculation, respectively, 1.4 and 1.2 times. The magnitude of these discrepancies for different structures of shut-off valves may differ from those indicated and depends on the number of parts included in the stop valve station. In this regard, the proposed calculation method allows determining not only the forces in the shut-off valve, but also the optimal number of parts and connections that will ensure safe operating conditions. It is shown that the method of calculating forces in the stop valve station used in practice is a special case in which the stiffness coefficient of the stop valve station a = 1. The proposed calculation method makes it possible to more accurately determine the forces acting in the shut-off valve, the sealing conditions and the stress--strain state of the parts.  The introduction of the developed calculation method is connected with the development of a regulatory document on its basis to replace the existing methods of calculating the stop valve station in shut-off valves.