Pneumatic hard seal ball valve is a commonly used control valve, which is widely used in petroleum, chemical, metallurgy, electric power and other industrial fields. It has the advantages of simple structure, good sealing performance, high pressure resistance, corrosion resistance, etc., so it is favored. This article will analyze the pneumatic hard seal ball valve in detail from two aspects: control mode and operation principle.
First, the control mode.
1.Manual control.
Pneumatic hard-seated ball valves can be controlled by a manual device. When the pneumatic system fails or the power fails, the switch of the ball valve can be controlled by a manual device to ensure the normal operation of the equipment. The manual control operation is simple and convenient, and it is suitable for emergency operation in some special situations.
2.Automatic control.
Pneumatic hard-seated ball valves can also be controlled by an automatic control system. The automatic control system can realize the automatic adjustment of the ball valve through the sensor and actuator according to the preset parameters, so as to realize the automatic operation of the equipment. Automatic control can improve production efficiency, reduce manual intervention, and reduce production costs.
Second, the principle of operation.
1.Structural composition.
The pneumatic hard seal ball valve consists of a pneumatic actuator and a ball valve body. The pneumatic actuator includes the cylinder, the pneumatic actuator control system and other parts, and the ball valve is controlled by the compressed air to drive the cylinder. The ball valve body is composed of a ball, a sealing ring, a valve stem and other parts, and the on-off control of the medium is realized by rotating the ball.
2.How it works.
When the air source is fed into the cylinder through the pneumatic actuator control system, the piston in the cylinder moves forward under pressure, pushing the valve stem to rotate the ball to the open or closed position, so as to achieve on-off control of the medium. When the air source stops ** or exhausts, the piston in the cylinder moves backward by the action of the spring force or the pressure of the medium, so that the ball returns to its initial position and the medium stops flowing.
3.Control principle.
The control principle of the pneumatic hard seal ball valve is to control the movement of the cylinder by adjusting the pressure of the air source, so as to realize the on-off control of the ball valve. When the pressure of the air source increases, the piston in the cylinder receives greater thrust, and the rotation angle of the ball increases; When the pressure of the air source decreases, the piston in the cylinder is subjected to less thrust and the rotation angle of the sphere decreases. By adjusting the pressure of the air supply, precise control of the opening and closing angles of the ball valve can be achieved.
To sum up, the pneumatic hard seal ball valve is a simple structure and reliable operation control valve, with a variety of control methods and flexible operating principles. It plays an important role in industrial production and provides reliable media control guarantee for the production process.