Abstract: The problem of abnormal forward opening of the check valve of gas water heater is studied. Through the analysis of dismantling parts, the components due to impurities jamming, material abnormalities and other factors, it is determined that the root cause of the problem is that the contact force between the valve stem and the rubber gasket is too large, resulting in excessive pushback resistance. Based on the theory of contact mechanics and frictional resistance, the two-dimensional axisymmetric finite element analysis method is used to simulate the existing check valve structure, and the situation of excessive contact force is clarified. Then, an optimization scheme for adjusting the cross-sectional shape of the rubber gasket is proposed, and the contact force and contact pressure are significantly reduced after optimization, which meets the design requirements. This scheme can effectively solve the problem of abnormal forward opening, and provides a reference for improving the performance of gas water heaters and reducing the failure rate of products.

Key words: Gas water heater, Check valve, Abnormal function, Structural optimization