OS&Y metal seated gate valve:
Closed status:
The gate is fully lowered to the lowest position under the drive of the valve stem.
The metal sealing surface of the gate is tightly pressed against the metal valve seat sealing surface of the valve body.
This forms a rigid seal between metals. The initial sealing force comes from the operating force (rotating the handwheel or actuator action). After the system pressure is established, the medium pressure will further act on the bottom of the gate, strengthening the sealing surface's pressing force and achieving reliable cutting. Metal seals can withstand high temperatures, pressures, wear, and erosion.

Opening process:
Rotate the handwheel or drive actuator clockwise (or according to the valve design direction).
The handwheel/actuator drives the valve stem nut to rotate.
Due to the valve stem nut being fixed on the bracket/valve cover, the rotating valve stem nut will drive the engaged valve stem to make upward linear motion.
The valve stem drives the bottom gate, overcoming the pressure of the medium (if the valve is under pressure) and the frictional force of the sealing pair, and vertically upward moves away from the sealing surface of the valve seat.
As the gate is raised, the passage inside the valve body gradually opens.
The valve stem moves upward, and its end gradually rises and extends relative to the valve cover. The operator can clearly see the upward movement of the valve stem, thus intuitively judging that the valve is opening. When the gate is raised to the fully open position (usually at a height equal to or slightly greater than the valve diameter), the channel is completely unobstructed with minimal flow resistance (close to a straight pipe).

The main advantages of the rising stem metal sealed gate valve are:
Intuitive indication: The valve stem position clearly displays the valve opening and closing status and approximate opening degree, making operation and maintenance convenient.
Low flow resistance: When fully open, the flow channel is almost unobstructed with minimal pressure drop.
Tight metal seal: suitable for media with high temperature, high pressure, corrosion, and strong wear resistance, with reliable sealing.
Durable and sturdy structure: The metal hard sealing pair has a long service life.
Dual flow: Usually designed as a bi-directional seal, fluid can enter from either side of the gate in any direction.