Calculation of Spindle of Pipeline Fittings on the Longitudinal Stability

The paper discusses the features of the rational design of a spindle with screwing motion of pipeline valve as the hinged rod with a step of change in stiffness, which takes into calculating the availability of both threaded and non-threaded parts and with the intermediate linear-elastic support to simulate the effect of supporting the glandsealing. A method of estimating the longitudinal stability of the spindle, which allows to consider heterogeneous components of its design individually and to determine the total value of the maximum load for the structure as a whole is offered. The method of calculating the effect of glandsealing supporting, taking into account the impact of its characteristics on the parameters of spindle's stability was developed.