Stress Distribution And Plastic Deformation Of Safety Valve Seats With The Effect Of Re-Seat Impact

Pressure relief valve is an important safety protection device in pressure systems, which need to be maintained good sealing performance as an important technical indicator. However, in reality, the sealing surface of the safety valve often fails to meet sealing requirements due to the defects of processing and the large deformation caused by the impact of Re-seat According to the requirements, this paper studies the stress distribution and plastic deformation on valve seat by computational simulation and experimental investigation using finite-element simulations, neutron diffraction measurement technology and three coordinate measurement technology. The main contents and conclusions of the study are as follows:(1) This study used Alembert principle to analysis calculate the impact time of Re-seat, and studies the effects of the size, structure of valve clack and the impact speed on the impact time. It can be found that the impact time was mainly related to size and rigidity of the contacting body.(2) The sealing performance of safety valve and the cushioning effect for Re-seat impact were studied by finite-element simulations with different valve clacks. It can be found that valve with smaller rigidity has a better sealing performance, and elastic valve clack can effectively reduce the impact stress.(3) The stress distribution and plastic deformation on valve seat were investigated using finite-element simulations, neutron diffraction measurement technology and three coordinate measurement technology. It can be found that the pre-impact at3ms-1speed between4and10times can to reduce the original residual tensile stress to a minimum to improve the life time of the relief valve. The plastic deformation of sealing surface and valve seat after impacting600times is small that it can be ignored the effect on the sealing performance and set-pressure of safety valve. A principle that a pre-impact can improve the structural integrity of the safety valve seat was proposed.