Abstract: Based on a study on the motion equation of 1D spring oscillator and the work characteristics of the check valve, it is concluded that the flutter of the spool of valve is the main reason for the check valve producing humming noise; According to the mechanism of the humming noise of the check valve, the optimization of spool inlet flow field, spool guiding structure and spring stiffness of the check valve are considered to be the main ways for designing low noise check valve; The low noise check valve is designed by the optimization of spool inlet flow field and spool guiding structure, some analysis and tests are performed and the new check valve noise improvement is verified. The test results show that the new check valve noise is improved by about 3dB on the whole unit, which is improved by 7dB at the key peak frequency band of 160Hz, and the sound quality of unit improved significantly.

Key words: A flutter of valve, Self-excited vibration, Double guiding structure, Velocity vortex