Improved pneumatic high vacuum butterfly valve

The utility model relates to an improved air-operated high vacuum butterfly valve. The utility model aims at providing a simple structural improved air-operated high vacuum butterfly valve, when the system is suddenly circuit broken, which can be closed fast, when the power supply system is recovered the power supply, the air-operated high vacuum butterfly valve can open slowly again. The utility model comprises a magnetic valve, an air inlet and outlet, a cylinder, a piston, a connector, a valve and a flange. One end of the two air inlets and outlets of the cylinder are both connected with the magnetic valve, the external of the piston is contacted with the flange, the valve is connected with the flange, characterized in that one of the air inlets and outlets is in series connected with an air inlet and outlet regulating valve, which has the advantage that when the system is circuit broken, the working air-operated high vacuum butterfly valve close fast, the close speed is adjustable between 0.5-1seconds, when the system recovering the power supply, which can open slowly again, the open speed is adjustable between 3-8seconds, the vacuum degree of the freeze-dried box is controlled not as far as rapid change and cause the product flying powder.