6 key factors for selecting plug-in valves

In working conditions such as powder conveying, pneumatic ash removal, metallurgy, electricity, and chemical engineering,slide gate valve(Also known as)Knife Gate Valve）Due to its compact structure, flexible opening and closing, and strong adaptability, it is widely used for opening and closing control of solid particles, slurries, and gas media.

However, different media and operating conditions have different requirements for the structure, sealing, and driving mode of the plug valve. Scientific selection is necessary to ensure the long-term reliable operation of valves and reduce maintenance costs. The following six key points are worth paying attention to in the selection of plug-in valves.

1、 The characteristics of the medium determine the valve structure

The medium is the first starting point for selection.

When dealing with media containing particles or abrasives, it is necessary to choose a blade type plug valve. The blade design can effectively cut off solid particles and prevent the valve plate from getting stuck.

If the medium is prone to adhesion, contains a lot of oil or colloidal substances, anti sticking coatings (such as PTFE, nickel plating or tungsten carbide coating) can be added to the surface of the valve plate or flow channel to reduce material accumulation and improve the smoothness of opening and closing.

For media with high moisture content or in the form of slurry, it is necessary to ensure that the valve chamber has a good self-cleaning structure to avoid liquid accumulation causing loose opening and closing.

2、 Temperature and pressure determine the sealing form

There are significant differences in sealing structure and material selection under different temperature and pressure conditions.

In normal temperature and low-pressure environments (such as ash removal or powder conveying), rubber or polytetrafluoroethylene soft seals can be used, with excellent sealing performance and moderate cost.

When the temperature of the medium exceeds 200 ℃ or there is obvious wear, the soft seal is prone to aging or damage, and should be switched to a metal hard seal structure.

At this time, it is recommended to use 304 stainless steel (CF8) or higher grade material for the valve body to ensure temperature resistance, wear resistance, and corrosion resistance.

3、 Flow direction and installation method

There are also requirements for the installation direction of plug-in valves.

For powder or dust media, vertical pipeline installation is the main choice to avoid material accumulation at the bottom of the valve chamber and reduce the risk of blockage.

If horizontal installation is necessary due to on-site limitations, it is recommended to add a blowing or ash discharge port at the bottom of the valve body, and regularly clean the valve chamber with compressed air or nitrogen to maintain cleanliness.

A reasonable installation method can not only extend the service life, but also ensure the stability of the opening and closing action.

4、 Matching driving mode with control requirements

The selection of the drive mode for the plug-in valve should be determined based on the operating frequency and degree of automation.

Handwheel drive: suitable for maintenance isolation or low-frequency opening and closing occasions, with a simple structure and low cost;

Pneumatic actuator: When the valve operates more than 10 times per hour, it is recommended to use pneumatic control for fast response and easy maintenance;

Electric actuator: Suitable for automation processes that require linkage with DCS systems, it can be configured with variable frequency control to achieve slow opening and closing, effectively preventing water hammer impact.

In continuous operation or remote control systems, it is recommended to choose intelligent electric actuators with position feedback devices for real-time monitoring of valve position status.

5、 Leakage standards and sealing levels

The leakage control of plug-in valves is directly related to process safety.

For gas, toxic gases, or hazardous media, the D-level leakage requirements of GB/T 13927 standard should be implemented to ensure the sealing reliability of the valve in working condition.

If the process requires "zero leakage" and a single valve structure is difficult to fully achieve, double valve series connection or installation of blind plate valves should be used for isolation to ensure dual safety barriers.

6、 Flange standards and interface matching

The flange standard is a crucial but easily overlooked part of the selection process.

Most domestic equipment uses GB/T 9119 standard flanges, with a common pressure rating of PN10.

If the project involves export equipment or requires docking with overseas systems, ANSI 150 flange specifications should be used, and the face-to-face (end face spacing) dimensions should be strictly checked to ensure compliance with ISO 5752 series 20 standards.

Once the flange standards do not match, it will lead to installation deviation or seal failure, increasing the difficulty of on-site rectification.

Conclusion

Although plug-in valves are common isolation devices, their selection is not universal.

From medium characteristics to sealing structures, from drive control to flange matching, every detail directly affects the safety and lifespan of the equipment.

Scientific selection ideas, mature manufacturing processes, and comprehensive application experience are the embodiment of a company's product competitiveness.

For the user unit, sufficient communication of operating conditions and clear parameters in the early stage are key to ensuring stable system operation and reducing maintenance costs;

For valve manufacturing enterprises, continuously optimizing design and refining selection standards are the true technical strength.