Structure of a Plug Valve
The structure primarily consists of the following core components:
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Valve Body
The housing providing the medium flow channel, designed with a groove-free structure to prevent medium jamming. The body of an inclined plug valve features the plug plate angled relative to the vertical direction to avoid material accumulation.
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Plug Plate (Gate Blade)
The key moving component, typically featuring a knife-gate or wedge-shaped structure. Its surface has a circular or square opening matching the pipe bore. Linear translation controls channel opening/closing. The inclined design further resolves material buildup issues.
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Sealing Structure
- Soft Seal / Hard Seal: Selected based on medium characteristics, featuring a floating valve seat design with automatic wear compensation.
- Special Sealing Materials: E.g., flue gas valves use diamond-shaped composite plates, combined with a seal air system for zero leakage.
- Wedge Sealing Surface: Electric plug valves employ a 50° wedge angle to form a self-locking seal.
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Actuating Mechanism
Consists of the valve stem and operating components (manual, electric, or hydraulic). The stem transmits force to move the plug plate vertically or at an incline. Hydraulic actuation is suitable for high-temperature flue gas environments, providing greater thrust.
Working Principle
The plug valve controls medium flow via the linear displacement of the plug plate:
- Open State: The actuating mechanism raises the plug plate, aligning its opening with the pipe bore for unimpeded medium flow.
- Closed State: The plug plate lowers, misaligning its opening with the pipe. The sealing surface presses tightly against the seat, cutting off the medium flow.
Inclined plug valves can additionally utilize the seal air system during operation to clear accumulated material, ensuring long-term reliability.
Classification and Characteristics
Type | Key Features | Application Scenarios |
Manual Knife Gate Valve | Full-bore design, anti-jamming; Soft/hard seal options available | Powder & granular conveying systems |
Inclined Plug Valve | Angled plug plate minimizes material accumulation; Temperature resistant up to 350℃ | High-temperature dust/pneumatic conveying |
Electric Plug Valve | Wedge self-locking seal; Bore sizes DN50-DN500 | Material control in metallurgy, building materials industries |


