Introduce the structure of the plug valve.

Release time:

2022-04-12

The slide gate valve is primarily composed of components such as a frame, gate plate, screw rod, and nut. By manually turning the handwheel, the screw rod drives the screw-nut assembly and the gate plate to reciprocate horizontally, thereby achieving the opening and closing of the gate. Pneumatic slide gate valves are widely used in fields such as metallurgy, mining, building materials, grain processing, and chemical industry. Pneumatic slide gate valve technical standards.

　　For slide valves with non-metallic sealing pairs, the shell and sealing tests shall be conducted using water (containing an anti-corrosion agent), kerosene, or other suitable liquids with a viscosity no greater than that of water. The requirements and procedures for the shell sealing test shall follow the relevant grading regulations. For slide valves with metallic sealing pairs, if sealing performance is required, the leakage rate in the sealing test shall be calculated as 1 × DN mm/s; if no sealing performance is required, this test need not be performed.

　　The plug valve driven by electric, hydraulic, or pneumatic actuators shall undergo three consecutive shell and sealing tests after the closing position has been adjusted, in accordance with requirements 1 and 3. The cleanliness requirements for the plug valve shall comply with the provisions of JB/T7748. A hydrostatic endurance test shall also be conducted. The number of cycles for the plug valve’s hydrostatic endurance test shall follow the specified regulations; other technical requirements shall adhere to the provisions of JB/Z 234.

　　The pneumatic slide valve is a key control device used for regulating the flow rate or conveying capacity of powders, granular materials, pellets, and small-sized bulk solids. It is widely employed in industries such as metallurgy, mining, building materials, grain processing, and chemical engineering to control flow variations or achieve rapid shut-off. The pneumatic slide valve offers several advantages: it features a simple structure, flexible operation, lightweight design, and no sticking or jamming. It is particularly well-suited for handling various solid materials as well as chunky or agglomerated materials measuring around 50 mm in size, and its flow regulation is highly effective. Installation is not restricted by orientation, operation is convenient, and the valve’s specifications can be adjusted at any time.

The vast majority of stainless steel knife gate valves employ forced sealing: that is, when the valve is closed, an external force is applied to forcibly press the gate against the high-pressure valve seat, thereby ensuring a tight seal on the sealing surfaces. Some gates can also be designed to undergo slight deformation, which helps improve their manufacturability and compensate for any misalignment in the sealing surface angles that may occur during the manufacturing process. Such gates are referred to as flexible gates. The majority of knife gate valves rely on forced sealing—meaning that when the valve is closed, an external force is used to press the gate firmly against the high-pressure valve seat, thus guaranteeing a secure seal on the sealing surfaces. Valves of this type are generally installed horizontally in pipelines.

2023-05-11

Next, let’s talk about several operating procedures for knife gate valves.

When a gate valve is closed, the sealing surfaces rely solely on the pressure of the medium to achieve a seal—specifically, the sealing surface of the gate is pressed against the valve seat on the opposite side by the medium’s pressure, thereby ensuring a tight seal. This type of sealing is known as self-sealing. In contrast, most gate valves employ forced sealing: when the valve is closed, an external force must be applied to press the gate against the valve seat in order to guarantee the sealing performance of the sealing surfaces. Such valves should be installed vertically in the pipeline.

2023-05-11

Next, let’s talk about whether knife gate valves have fire-resistant and anti-static requirements.

When an electrostatic knife gate valve is opened or closed, the sphere and the valve seat experience mutual friction. The static electricity generated by this friction tends to accumulate on the sphere—something that is unacceptable for ball valves used in gas, fuel, and chemical pipelines, as it could potentially lead to pipeline explosions. Ball valves with antistatic designs are equipped with static discharge devices.

2023-05-11

Next, let’s talk about some important considerations for the installation, operation, and maintenance of pneumatic knife gate valves.

Pneumatic knife gate valves have a wide range of applications, spanning from ordinary fields to more diverse industries—from coal preparation, gangue removal, and slag discharge in coal-fired power plants to urban wastewater treatment; from general industrial pipelines to pipeline systems used in food, sanitation, and pharmaceutical industries. So, what are the key considerations when installing, using, and maintaining pneumatic knife gate valves?

2023-05-11

Slurry Valve Manufacturer: How are stainless steel knife gate valves good?