Gate valves are stop valves and do not seal as well as globe valves. Gate valve main 'duty' is 'cut off', as well as the minimum resistance. Gate valve in the full open the entire flow path straight through, the media running at this time the minimum pressure loss, its main advantage is the fluid flow resistance is small, ordinary gate valve flow resistance coefficient of about 0.08 ~ 0.12, gate valve is usually applicable to do not need to open and close often, and to keep the gate fully open or fully closed conditions, is not suitable for regulating, throttling, such as long-term use for regulating, the sealing surface is easy to be flushed by the media wear and tear, affecting the sealing performance. Sealing performance.
Gate valve medium temperature, pressure, reliability of use should be noted.
Gate valve in the opening and closing of the spool and seat sealing surface is always in contact with each other and friction, so the sealing surface is easy to wear, especially in the valve is close to the closed state, the spool before and after the pressure difference is very large, the sealing surface wear is more serious; gate valve sealing surface has a certain degree of self-sealing ability, its spool rely on the media pressure to tightly with the seat sealing surface contact to achieve a tight leakage. Wedge gate valve spool slope is generally 3 ~ 6 degrees, when the forced closure of excessive or large temperature changes in the spool is easy to jam. Therefore, high temperature, high pressure wedge gate valve, in the structure have taken certain measures to prevent the spool jammed.
Gate valve in the fully open when the entire flow path straight through, at this time the medium of the operation of the minimum pressure loss, its main advantage is the fluid flow resistance is small, the flow resistance coefficient of the ordinary gate valve is about 0.08 ~ 0.12, the gate valve is usually applicable to the valve does not need to be opened and closed frequently, and to keep the gate fully open or fully closed conditions, is not suitable for regulating, throttling use.