GUQ-A series pneumatic vacuum (pressure) ball valves are suitable for connecting or cutting off medium flow in pipelines in vacuum systems. The valve is powered by compressed air and changes the direction of the air circuit by controlling the pneumatic components, driving the mechanical movement of the piston rack and gear, and outputting torque through angular stroke to drive the ball valve for opening and closing motion. The valve is a straight through type, sealed by a spherical surface, which can be used in both vacuum and low-pressure conditions, and can be installed in any position. The cylinders are divided into double acting and single acting (spring return), and can be equipped with feedback signal devices and electrical valve positioners. The applicable working medium is gas or liquid with acid or alkaline content.