1. Core Working Principle
Pressure-Enhanced Sealing Mechanism
When closing, media enters from the high-pressure side, pushing the gate toward the low-pressure side. This simultaneously compresses the flexible sealing element (such as a graphite ring or metal seal) at the junction of the bonnet and valve body.
The greater the media pressure, the more pronounced the sealing element deformation, automatically filling the gap between the sealing surfaces, achieving a zero-leakage seal.
2. Key Structural Design
Valve Body Assembly
Self-sealing ring: Made of flexible graphite or alloy, it plastically deforms to fill gaps under pressure.
Bidirectional pressure-bearing gate: Provides a seal regardless of the direction of flow.
Forged steel body: Enhanced pressure-bearing capacity (e.g., A105, F11).
Operating Characteristics
Low opening resistance: When the valve opens, media pressure is released, and the seal rebounds.
No friction loss: Non-contact sealing between the gate and seat extends service life.
3. Performance Advantages and Limitations
| Advantages | Limitation |
|---|---|
| High-pressure zero leakage: Leakage rate meets ANSI Class VI standards under 42MPa working conditions | Sensitive to granular media: solid impurities may damage the seal |
| High temperature resistance: -20°C to 550°C (steam/oil and gas working conditions) | Higher cost: complex forging process |
| Easy maintenance: The sealing ring can be replaced without disassembling the valve body | Small diameter limit: DN15~DN200 (large diameter needs to be customized) |
4.Typical Application Scenarios
Ultra-High-Pressure Systems
Power Plant Main Steam Pipeline (PN420);
Petroleum Cracking Unit (2500LB Class);
High-Temperature Corrosive Environments
Chemical Reactor High-Temperature Media Shutoff (316L Valve Body);
Geothermal Energy Pipeline (Sulfur Corrosion-Resistant Seals)