Dynamic Stability Criterion for Reed Valves in Refrigerant Compressors

Abstract

One of the most significant vibration sources of higher-frequency noises in refrigerant compressors used for air conditioners or refrigerators is the reed valve which controls the refrigerant gas flow from the discharge port. In order to examine the higher-frequency vibrations of the reed valve exposed to compressed gas flow, we conducted a vibration test for a simple axisymmetrical model consisting of a valve, valve plate, cylinder and piston. First, compressed air entered the flow chamber through a capillary tube at the piston center, and the valve was excited to induce a forced vibration over as wide a frequency range as possible. Then, the fluid pressure in the flow chamber was measured for different cylinder volumes to determine the amplitude and the phase lag relative to the valve vibration, thus making it possible to obtain a dynamic stability criterion for self-excited vibration of the reed valve. Secondly, a free vibration test was performed on the reed valve to verify that the reed valve actually experiences self-excited vibration when the dynamic stability criterion obtained from the forced vibration test is not satisfied. In addition, the vibration frequency and self-excitation level of the reed valve were examined.