Installation and Usage Instructions for Knife Gate Valves

Release time:

2021-08-30

Gate Valve Maintenance 1. The handwheel, handle, and actuator mechanism must not be used for lifting purposes, and collision is strictly prohibited. 2. Double-disc gate valves should be installed vertically (i.e., the valve stem should be in a vertical position, with the handwheel at the top). 3. For gate valves equipped with a bypass valve, the bypass valve should be opened first before opening the main valve (to balance the pressure difference between the inlet and outlet and reduce the opening force). 4. For gate valves with an actuator mechanism, install them according to the instructions provided in the product manual. 5. If the valve is frequently opened and closed, lubricate it at least once a month.

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Installation and Usage Instructions for Knife Gate Valves

1. Before installing the knife gate valve, it is essential to inspect the valve cavity and sealing surfaces for any contaminants or sand particles; such impurities are not permitted.

2. The bolts at all connection points must be tightened evenly.

3. The packing area must be tightly compressed to ensure both the sealing performance of the packing and the smooth operation of the gate valve.

4. Before installing the valve, users must verify the valve model, connection dimensions, and pay attention to the flow direction of the medium to ensure consistency with the valve’s requirements.

5. When installing the valve, users must reserve sufficient space for the valve actuator.

6. The wiring of the drive unit must be carried out according to the wiring diagram.

7. Gate valves must be regularly maintained and should not be subjected to random impacts or compression, as this could compromise the seal.

Knife Gate Valve Maintenance

1. The handwheel, handle, and transmission mechanism must not be used for lifting purposes, and collisions are strictly prohibited.

2. A double-disc gate valve should be installed vertically (i.e., the valve stem is in a vertical position, and the handwheel is at the top).

3. Before opening a gate valve equipped with a bypass valve, the bypass valve should be opened first (to balance the pressure difference between the inlet and outlet and reduce the opening force).

4. Install the gate valve with belt drive mechanism according to the instructions provided in the product manual.

5. If the valve is frequently opened and closed, lubricate it at least once a month.

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?