Air volume control valve capable of accurately measuring air volume

An air volume control valve capable of accurately measuring an air volume, comprising a round-shaped valve body, and a valve blade and an orifice plate provided in the round-shaped valve body, wherein

• the orifice plate is located upstream of the valve blade;
• an upstream pressure tapping port and a downstream pressure tapping port are respectively provided upstream and downstream of the orifice plate;
• a distance from both the upstream pressure tapping port and the downstream pressure tapping port to the orifice plate is 0.5 times a valve diameter of the round-shaped valve body;
• and the valve blade is located downstream of the downstream pressure tapping port;
• and
• an inlet side of the round-shaped valve body is provided with a convergent duct fitting;
• and the convergent duct fitting is located at a distance of once the valve diameter upstream of the orifice plate and is tapered along an air flow direction;
• wherein the orifice plate is provided with a circular inner hole;
• and the circular inner hole has a diameter that is 0.2-0.8 times the valve diameter;
• wherein the round-shaped valve body is divided into an air volume measurement section and an air volume regulation section;
• the air volume measurement section is centered on the orifice plate and has a length that is twice the valve diameter;
• and the air volume regulation section is centered on a shaft of the valve blade.