Overview of pneumatic knife gate valve
Pneumatic knife gate valve is a valve driven by compressed air. To put it simply, the pneumatic knife gate valve uses a pneumatic actuator to control the valve, thus realizing the opening and closing of the valve. It can be divided into two parts: the upper part is a pneumatic actuator, and the lower part is a valve. Such valves shall generally be installed horizontally in the pipeline.
1、 Product features
The opening and closing part of the pneumatic knife gate valve is the ram, and the movement direction of the ram is perpendicular to the fluid direction. The manual knife gate valve can only be fully opened and closed, and cannot be adjusted and throttled. The gate has two sealing surfaces. The two sealing surfaces of the common mode gate valve form a wedge shape. The wedge angle varies depending on the valve parameters and is usually 50. The gate of wedge-shaped knife gate can be made into a whole, which is called rigid gate; It can also be made into a gate that can produce slight deformation to improve its technological performance and make up for the deviation of sealing angle during processing. When this kind of gate is called elastic gate, the sealing surface can only be sealed by medium pressure. That is, the sealing surface of the ram is pressed on the valve seat on the other side by the medium pressure to ensure the sealing of the cover, i.e. self sealing Most knife gate valves adopt forced sealing, that is, when the valve is closed, the gate plate shall be pressed into the valve seat by external force to ensure the sealing of electric knife gate valve, pneumatic knife gate valve and American standard knife gate valve products. Precautions and characteristics: the opening and closing part of knife gate valve is the gate plate, and the movement direction of the gate plate is perpendicular to the fluid direction. The knife gate valve can only be fully opened and closed, and cannot adjust the flow. The gate has two sealing surfaces. The two sealing surfaces of the commonly used mode gate valve form a wedge shape, and the wedge angle varies with the valve parameters, usually 50. The gate of the wedge knife gate valve can be made into a whole, called a rigid gate; It can also be made into a ram that can produce slight deformation to improve its processability and compensate for the deviation of the angle of the sealing surface during processing. This ram is called an elastic ram. When the knife gate valve is closed, the sealing surface can be sealed only by the medium pressure
2、 Development and application
He entered China in the 1980s. In less than 20 years, its scope of use has expanded from ordinary fields to a wider range of industries. Coal preparation, gangue discharge and slag discharge from mining power plants. From general industrial pipelines to specialized pipeline systems for food, sanitation, medicine, etc., to urban sewage treatment. The ultra-thin knife gate valve, with its advantages of small volume, small flow resistance, light weight, easy installation and disassembly, completely solves the difficult problems of large flow resistance, large weight, difficult installation and large floor area of ordinary gate valve, flat gate valve, ball valve, globe valve, regulating valve, butterfly valve and other valves. After the appearance of knife gate valve, it has replaced a large number of universal shut-off valves and regulating valves. Today, the United States and Japan are the largest consumers of knife gate valves in the world.
3、 Working performance
Working performance and installation of pneumatic knife gate valve:
The pneumatic knife gate valve has the advantages of simple and compact structure, reasonable design, light material saving, reliable sealing, flexible operation, small volume, smooth passage, small resistance, light weight, convenient installation and disassembly. 0MPa-2.5MPa, and the operating temperature is - 29-65 ℃. The gate plate of the knife gate valve has a shearing function, which can scrape the adhesive on the sealing surface and automatically remove impurities. The stainless steel gate plate can prevent corrosion caused by seal leakage.
4、 Installation and use
1. Before installation, check the valve chamber and sealing surface to ensure that no dirt or sand particles are attached;
2. The bolts of all connecting parts shall be tightened evenly;
3. Check the packing position to ensure the tightness of the packing and the flexible opening of the ram;
4. Before installing the valve, the user must check the valve model and connection size, pay attention to the medium flow direction, and ensure that it is consistent with the valve requirements;
5. When installing the valve, the user must reserve the necessary valve driving space;
6. The wiring of the drive device must be carried out according to the circuit diagram;
7. The pneumatic knife gate valve must be maintained regularly and cannot be collided and squeezed at will to avoid affecting the sealing.
