The main types of gate valves include rising stem gate valves and concealed stem gate valves. The valve stem thread and nut of the rising stem gate valve do not contact the medium, are not affected by the medium temperature and corrosion, and the degree of opening is obvious and easy to see, so it is widely used; while the valve stem thread and nut of the concealed stem gate valve are in contact with the medium, affected by the medium temperature and corrosion, but the height of the valve is small, suitable for non-corrosive media and occasions with poor external environmental conditions.
In addition, gate valves can also be divided into reduced diameter gate valves and equal diameter gate valves according to whether the diameter of the channel in the valve body is consistent. The diameter of the valve seat of the reduced diameter gate valve is smaller than the diameter of the flange connection, and the diameter of the valve seat of the equal diameter gate valve is consistent with the diameter of the flange connection. The reduced diameter design can reduce the size of the parts and reduce the force required for opening and closing, but it will increase the fluid resistance loss.