The Mechanism of Metal Sealing Valve
The sphere of metal sealing valve is a combination valve. There is a wedge-shaped cone in the center. Two 5-degree slopes are on both sides, which have two spherical valve flaps with slopes. The spherical valve flap and the cone are connected by dovetail groove or T-slot. They can slide against each other. There are limit ring and adjustment pad at the upper and lower part of the spherical valve flap respectively, so that it can’t rise or fall with the wedge-shaped cone, but can only be moved horizontally or rotated with the wedge-shaped cone in a horizontal space. The lower end of the valve stem is fixated with the wedge-shaped cone through threads and pins. At the upper end of the valve stem, the trapezoidal thread works with the valve stem nut. The rotation of the stem nut is actuated by hand wheel, bevel gear, electric or pneumatic device. There is a track pin in the middle of the valve stem. At both ends of the pin are installed rollers. The rollers can roll inside the guide groove of the bracket. The movement path of the valve stem is limited by the guide groove.
When the valve needs to be closed, turn the hand wheel clockwise to drive the stem nut to rotate. The stem nut drives the stem and wedge-shaped cone to rotate 90 degrees to the closing position of the valve before extending horizontally towards both sides and moving towards the sealing surface of the valve body, achieving the closing of the valve. When the valve needs to be opened, turn the hand wheel counterclockwise to drive the stem nut and stem to move up the wedge-shaped cone, which makes the valve flap shrink to the center and leave the sealing surface of the valve body. Then, the wedge-shaped cone drives the valve flap to rotate 90 degrees to open the valve.
The movement path of metal sealing valve has the characteristics of both gate valve (multi-turn) and sanitary ball valve (90-degree turn), so its performance has the advantages of both gate valve and ball valve. The structures of metal sealing valve and ball valve have both similarities and differences.