Trunnion Type Ball Valve – API 6D High Pressure Pipeline Valve

Description

For high-pressure, large-diameter pipeline systems in the oil, natural gas, and chemical industries, the selection of valves directly impacts the safety and efficiency of the entire process. Compared with traditional floating ball valves, which rely on fluid pressure to push the ball against the downstream seat, the trunnion type ball valve achieves a fundamental breakthrough in structural design.

The trunnion type ball valve uses fixed shafts (Trunnions) at both the upper and lower ends of the ball for support, and is equipped with load‑bearing bearings. This design fixes the ball in position, so that under high‑pressure conditions, the ball does not displace downstream. The seats are spring‑loaded and floating, maintaining constant contact with the ball surface.

This mechanical advantage brings two direct results: operating torque is significantly reduced (typically by 60%‑70%), allowing easy manual or electric operation even in large‑diameter pipelines; at the same time, high‑pressure sealing performance is substantially improved, making it particularly suitable for extremely high differential pressure environments.

Product Technical Parameters

Components and Precision Design

For critical positions in high‑pressure natural gas pipelines or long‑distance transmission lines, valves must offer extremely high reliability and emergency response capability.

Our trunnion mounted valve is strictly designed in accordance with API 6D, and comes standard with a blowout‑proof stem and anti‑static device. An optional emergency sealant injection system is also available, ensuring that temporary sealing can be achieved by injecting sealant in the event of accidental seat damage, thus meeting emergency repair requirements for long‑distance pipelines.

Regarding the bidirectional sealing capability of the API 6D trunnion ball valve, the design allows the valve body to incorporate double block and bleed (DBB) functionality, meaning that cavity pressure can be safely relieved to prevent over‑pressure risks due to thermal expansion of the medium. This has become a standard requirement for international long‑distance pipeline projects.

Application Scenarios and Industry Selection

Unlike the floating ball valve vs trunnion principle, where sealing relies on medium pressure to push the ball, the mechanical stability of the trunnion‑mounted ball valve makes it the preferred choice for high‑pressure and large‑diameter applications.

• Long‑distance pipelines and gathering systems: Suitable for long‑distance transport of crude oil, refined products, and natural gas, especially where frequent on‑off or emergency shutdown operations are required, using the gear operated trunnion ball valve mode.

• City gate stations and gas storage facilities: Used for receiving, metering, and pressure‑regulating skid equipment for high‑pressure gas.

• Petrochemical and chemical plants: For high‑temperature, high‑pressure steam or fluids containing particulates, the metal seated ball valve hard‑sealing configuration can be selected. Combined with the online maintenance capability of the top entry trunnion ball valve (allowing internal seat replacement without removing the valve body from the pipeline), this greatly reduces downtime maintenance costs.

Packaging and Shipping

All large‑diameter and high‑pressure trunnion type ball valves are securely packed in fumigation‑free solid wooden crates or heavy‑duty steel frames. Before leaving the factory, each valve undergoes a high‑pressure dry nitrogen test, with both ends sealed by engineering plastic end caps and desiccant placed inside to prevent corrosion during transit.

The outer packaging clearly marks the center of gravity, as well as moisture‑proof and fragile symbols. Each shipment includes a complete set of quality inspection documents (including material certificates, hydrostatic/pneumatic test reports, and torque test records).