When sanitary pneumatic ball valve is closed, the hand wheel is clockwise, the stem began to decline and to leave the seat to rotate a sphere. Continuing to rotate handwheel, stem were embedded in the spiral groove of the guide pin, is abo…

How to select the valve according to the nature of the valve drive1 power driven valvePower driven vacuum valve is commonly used to drive the valve, usually referred to as the form of the drive device for the valve electric device, valve e…