This 14" 4500LB F91 pressure seal gate valve is designed for high-temperature and high-pressure power plant boiler service. It features ASTM A182 F91 Type 2 material, a pressure seal bonnet, parallel double disc structure, BW ends, AOX electric actuator, and bypass valve for pressure equalization.
Payment:
30% when order confirmed, 70% before shipmentProduct Origin:
chinaColor:
CustomizationShipping Port:
Shanghai, ChinaLead Time:
30~60 days Ex Works after order confirmationMaterial:
ASTM A182 F91 Type 2Method of Operation:
AOX Electric Actuator
This 14" Class 4500 F91 pressure seal gate valve is designed for high-temperature and high-pressure power plant boiler service, combining a pressure seal bonnet structure with forged high-temperature alloy steel construction.
The valve adopts a parallel double disc, rising stem, full-bore design with BW ends, electric actuation, and a bypass valve for pressure equalization. This configuration is suitable for severe steam and boiler pipeline isolation where pressure class, material strength, sealing reliability, and controlled operation are critical.
Constructed from ASTM A182 F91 Type 2, the valve provides high-temperature strength for service conditions with a design temperature of 649 deg C. The BW connection according to ASME B16.25 helps reduce flange leakage risk in severe service pipelines, while API 598 testing verifies pressure-containing and sealing performance before shipment.
This Class 4500 configuration is suitable for power plants, boiler systems, high-temperature steam pipelines, and other severe high-pressure isolation applications.
|
Type |
Pressure Seal Gate Valve |
|
Size |
14" / DN350 |
|
Pressure Rating |
Class 4500 / 4500LB |
|
Structure |
Parallel Double Disc, Rising Stem, Full Bore |
|
Connection |
BW |
|
Operation |
AOX Electric Actuator |
|
Body / Bonnet Material |
ASTM A182 F91 Type 2 |
|
Disc / Seat |
F91 + STL |
|
Stem |
F6A 2 + N |
|
Trim |
#5 |
|
Design Standard |
ASME B16.34 |
|
End Connection Standard |
ASME B16.25 |
1. Pressure Seal Bonnet for Class 4500 Service
The pressure seal bonnet is suitable for high-pressure boiler and steam pipeline applications. As internal pressure increases, the bonnet sealing effect is strengthened, helping improve sealing reliability under severe pressure conditions.
2. ASTM A182 F91 Type 2 High-Temperature Material
F91 high-temperature alloy steel provides better high-temperature strength and creep resistance than ordinary carbon steel. It is commonly selected for power plant boiler and high-temperature steam service.
3. Parallel Double Disc, Rising Stem Design
The parallel double disc structure supports stable shut-off performance in high-pressure service. The rising stem design also helps operators confirm valve position during operation and maintenance.
4. BW Ends for Severe Pipeline Connection
The valve uses butt-weld ends according to ASME B16.25. BW connection is suitable for high-temperature and high-pressure pipelines where a welded connection is preferred to reduce potential leakage points.
5. Electric Actuated Operation
The AOX electric actuator supports controlled opening and closing, which is useful for a 14 inch Class 4500 valve where manual operation may be difficult due to high torque and severe service conditions.
6. Bypass Valve for Pressure Equalization
The bypass valve helps equalize pressure before the main valve is operated. This reduces operating load, protects the actuator, and improves operation stability under high differential pressure.
7. Tested to API 598
The valve is tested according to API 598. The specified shell test pressure is 116.4 MPa, and the seat test pressure is 47.4 MPa, supporting reliable pressure and sealing verification before delivery.
Tailored Configurations for High-Temperature and High-Pressure Applications
Beyond the base configuration, this pressure seal gate valve can be customized according to power plant and boiler pipeline requirements. Available options include electric or gear operation, bypass valve arrangement, drain and vent connections, extended stem, special trim, hardfacing, actuator accessories, and customized testing or documentation.
For applications involving severe thermal cycling, high-pressure steam, or thick-wall butt-weld piping, material selection, pressure class, trim design, welding end preparation, actuator torque, and testing requirements should be confirmed before production.

For a large-size Class 4500 gate valve, high differential pressure across the disc can increase operating torque and create additional load during opening. The bypass valve allows pressure to be balanced before the main valve is operated.
This design helps improve operation safety and stability in high-pressure boiler service, especially during start-up, shutdown, or maintenance preparation.
Each valve can be inspected and tested before shipment according to API 598 and project-specific requirements. For this 14 inch Class 4500 pressure seal gate valve, the specified shell test pressure is 116.4 MPa and the seat test pressure is 47.4 MPa.
Recommended inspection items include material certificate review, dimensional inspection, visual inspection, shell test, seat leakage test, actuator function test, bypass valve inspection, nameplate verification, painting inspection, packing inspection, and final document review.




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