The non ring stem gate valve is one of the structural forms of the gate valve, corresponding to the ring stem gate valve. The biggest difference between the two is the appearance and structural features. The structural characteristics of the non ring stem gate valve is that its stem and nut are inside the valve body and will directly contact the fluid medium, which also makes the stem of the non ring stem gate valve easily corroded.
The open and close parts of the non ring stem gate valve are gate plates. The gate plate moves up and down around the valve stem to open and close the valve. The direction of movement of the gate and the direction of flow of the medium in the pipeline are perpendicular to each other. As with other types of gate valves, the non ring stem gate valve can only be fully opened and fully closed and cannot be used for flow regulation. When the gate is fully open, the resistance of the medium flowing through the passage of the valve body is minimal.
The working principle of the non ring stem gate valve: As the stem moves up and down in a straight line, the valve stem is threaded. When the valve stem is turned, under the action of the nut on the top of the valve and the guide groove above the valve body, the valve stem will do a straight up and down movement, the valve stem drives the gate to move at the same time. The direction of movement of the gate is perpendicular to the direction of flow of the medium in the pipeline.
Because the stem thread is inside the valve body, the non ring stem gate valve cannot be opened in the same way as the open stem gate valve.In general, non-rising stem gate valve open/close status to turn stem so far, but consider the special situation, valve lock condition, in order to ensure the safety of pipeline production, non-rising stem gate in to turn the valve stem not move, then return 1 ~ 2 times.
The overall height of the non ring stem gate valve will not change in the working process, so the non ring stem gate valve occupies less space when installing, which is more suitable for indoor and other limited space environment.
There are many kinds of driving methods of the non ring stem gate valve, such as manual, gear transmission, pneumatic, electric, etc. We can choose the corresponding driving method according to the characteristics and requirements of our operating conditions.