Performance and application of pneumatic downward expansion discharge valve: easy to operate, no flow resistance when opened; The valve disc assembly and maintenance are simple, the sealing structure is reasonable, and the sealing ring replacement is convenient and practical.

Pneumatic downward expansion discharge valve is a valve controlled by pneumatic actuator. The pneumatic downward expansion structure mainly consists of valve body, valve disc, sealing ring, valve stem, bracket, valve cover, pneumatic actuator, flange, nut, positioning screw and other parts.

1. The pneumatic discharge valve is suitable for media such as water, acetone, alcohol, ammonia, barium carbonate, and benzene (the low temperature of WCB material is -29 ℃, and the high temperature is 425 ℃).

2. Use media such as particles, oil, pulp, carbon dioxide, and gas (stainless steel material has a low operating temperature of -100 ℃ and a high operating temperature of 232 ℃).

3. It is strictly prohibited to use fluorine-containing ionic liquids (such as HF), as well as strong bases and phosphoric acid (temperature>150 ℃, concentration>30%).

(1) The sealing surface is evenly worn and lightly scratched, with good sealing performance

The disc and stem of the upward and downward discharge valves are connected as a whole, with good rigidity, uniform wear, reliable sealing performance, and long continuous service life.

(2) The opening and closing stroke is different, and the installation size varies

The opening and closing stroke of the upward and downward discharge valves is small, and the installation height is small.

The plunger type discharge valve is divided into two structural forms: lifting rod and rotating rod according to the plunger structure and movement mode. The lifting rod structure requires a large installation space, but the opening and closing and position of the valve can be intuitively judged based on the plunger movement mode and position. The installation height of the rotating rod structure is small, and the plunger only rotates during the opening and closing process. It needs to determine the opening and closing and position of the valve based on the opening and closing position indicator.

(3) Different opening and closing torques

The upward sliding discharge valve is a valve that opens when the valve disc moves upward. When opening, the valve needs to overcome the force of the medium, and the opening torque is greater than the closing torque.

The downward sliding and plunger type discharge valves open by the downward movement of the valve disc (plunger). When opened, the direction of movement is the same as the medium force, so the opening torque is smaller than the closing torque.

The discharge valve is mainly composed of a valve body, a valve disc (plunger), a valve stem, a sealing packing, and a driving mechanism. The valve disc is the opening and closing member of the upward expansion discharge valve, generally in the shape of a disc or column, and it forms a sealing pair with the valve body and seat. The discharge valve is divided into three types: upward expansion type, downward expansion type, and plunger type. Its valve disc is available in conical and spherical shapes, as well as soft seals and metal metal hard seals.

The discharge valve is widely used in various fields such as chemical, petrochemical, petroleum, papermaking, mining, electricity, liquefied gas, food, pharmaceuticals, water supply and drainage, municipal, mechanical equipment supporting, electronic industry, urban construction, etc.