A flange gate valve controls the opening and closing of the valve by lifting and lowering the gate plate. The gate plate is perpendicular to the fluid direction, and changing the relative position between the gate plate and the valve seat can change the channel size.
Characteristics of flange gate valve:
1. The handwheel on the surface of the valve is made of malleable cast iron, designed to match the handle and increase friction appropriately for easy opening. And there are obvious “on” and “off” signs.
2. The valve stem nut is made of high nickel ductile iron, and the thread is matched with the valve stem to transmit torque.
3. There is an oil cup on the valve cover, which can be regularly replenished with solid lubricating oil to maintain easy opening and closing.
4. The packing gland and pressure sleeve are designed separately to ensure the concentricity of the valve stem. Reasonable packing box design ensures that the valve has no leakage and meets environmental requirements.
5. The connecting bolts of the middle flange of the valve are double headed bolts, which are convenient for maintenance and disassembly.
6. The valve stem head is forged as a whole and connected to the valve disc through a groove to ensure strength.
7. The handwheel transmits torque to the valve stem through the valve stem nut, and the valve stem is forged and tempered. In order to reduce the loss of force during transmission, the valve stem nut is made of high nickel ductile iron or copper alloy (high nickel ductile iron has a certain degree of self-lubricating properties), which has a lower hardness than the valve stem.
8. The valve stem head is equipped with an upper sealing surface that is sealed with the valve cover sealing pair. When the medium used is special, it is required that the valve has no leakage when fully opened.
9. The connection between the valve stem head and the gate plate adopts a groove structure, with a certain degree of freedom between the two, allowing the gate plate to smoothly slide into the valve seat along the valve body guide rib.
10. The sealing surface of the gate is wider than the sealing surface of the valve seat by a certain margin, and it is ensured that the bottom line of the sealing surface of the gate is at the same height as the bottom line of the sealing surface of the valve seat before use, so that even if the valve wears out after a certain period of use, the width of the sealing surface that must be guaranteed will not decrease.