Combination air valve

The main purpose of the research was to investigate a combination air valve, it's sketch can be seen above. The experiments were performed in our laboratory, where visual acces was available to the pipeline, and they revealed that if the pressure drops below the ambient the valve opens quickly then air enters the system and increases the inner pressure. Pressure data was recorded with high frequency (10kHz) at multiple locations of the system. The measurements pointed out the air valve is capable of preventing the vacuum, but additional loading appers with high amplitude for a short time, see figures below.