Pressure Seal Bonnet Gate Valves

Pressure-sealed bonnet gate valve is a special structure of the American standard high-pressure gate valve. Its core feature is to use the medium pressure to enhance the sealing of the bonnet. It is mainly used for high-pressure conditions of Class 600 and above.
Structure:
Pressure self-sealing bonnet
It adopts a conical sealing ring + compression bolt structure. The internal medium pressure pushes the sealing ring to expand outward, so that the higher the pressure, the tighter the seal;
It replaces the traditional bolt bonnet to avoid leakage caused by bolt stress relaxation under high pressure.
Elastic wedge gate
There is an annular groove in the middle of the gate, which can be slightly deformed at high temperature to compensate for thermal expansion and prevent jamming;
The sealing surface is welded with cobalt-based cemented carbide (such as STL) to resist erosion and wear.
Double sealing system
Main seal: hard seal between the gate and the valve seat; Upper seal: When the valve stem is fully open, it forms an auxiliary seal with the valve bonnet, allowing the packing to be replaced under pressure.
Extended stem design
High-temperature expansion space is reserved, and the nitriding treatment of the valve stem surface improves the abrasion resistance.

 

Pressure Seal Bonnet Gate Valves

 

 Advantages ‌
‌High-pressure zero leakage‌
The medium pressure drives the sealing ring to tighten, and zero leakage is maintained under Class 2500 (42MPa) working conditions; ‌

Resistant to thermal shock‌
The extended valve cover + elastic gate design adapts to 593℃ severe temperature fluctuations; ‌

Convenient maintenance‌
Replace the packing under pressure (when the upper seal is effective) to avoid system shutdown; ‌

Lightweight and creep-resistant‌
The forged steel valve body is 20% lighter than cast steel and has stronger deformation resistance at high temperatures.

 Applications ‌

Supercritical power generation‌
Main steam pipeline (pressure ≥26MPa, temperature ≥566℃); ‌

Petrochemical hydrogenation unit‌
Hydrogenation reactor inlet and outlet pipelines (Class 1500~2500); ‌

Nuclear power system‌
Primary circuit coolant pipeline (nuclear grade certification requirements); ‌

High-pressure synthesis process‌
Coal-to-liquid, methanol synthesis and other ≥10MPa reaction systems.

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