The KFTE Trunnion Ball Valve is the ball valve of choice for larger sizes and higher pressure applications, particularly in pipelines and critical process systems. Such products are widely used in heavy-duty industrial flow control environments where safety and reliability are essential.These valves incorporate advanced trunnion ball valve design features, including a built-in cavity relief mechanism, anti-static capability, and an intrinsic double block and bleed function. Additionally, all KFTE Trunnion Ball Valves undergo fire-safe testing in compliance with API 607/API 6FA standards.
KFTE Trunnion Ball Valves are designed for high-pressure and demanding industrial flow control applications, particularly in pipelines and critical process systems. Unlike floating ball valves, the ball is mechanically supported by upper and lower trunnions, which absorb line-pressure forces and reduce the load transferred to the valve seats.
This fixed-ball design helps achieve lower operating torque, stable ball alignment, and reliable sealing under demanding operating conditions. KFTE Trunnion Ball Valves are available in cast and forged configurations and can be selected according to application requirements, pressure conditions, materials, and installation needs.
The design also incorporates features such as cavity pressure relief, anti-static protection, blow-out proof stem construction, and double block and bleed capability. KFTE Trunnion Ball Valves are fire-safe tested in accordance with API 607 / API 6FA requirements.
A trunnion ball valve is a quarter-turn ball valve in which the ball is fixed in position by mechanical supports called trunnions. Unlike a floating ball valve, the ball does not move freely toward the downstream seat when line pressure increases.
The upper and lower trunnions support the ball and absorb a significant portion of the hydraulic thrust generated by the fluid. This reduces the force acting directly between the ball and seats and allows the valve to operate with relatively low torque even in demanding pressure conditions.
This construction makes trunnion mounted ball valves particularly suitable for pipelines, process systems, and other applications where reliable isolation and controlled operating torque are important.
A trunnion ball valve controls fluid flow by rotating the ball through approximately 90 degrees.
When the ball passage is aligned with the pipeline, the valve is open and fluid can pass through the flow path. When the ball is rotated so that the passage is perpendicular to the pipeline, the ball blocks the flow and the valve is closed.
The trunnion support system plays an important role during operation:
Ball support
Upper and lower trunnions hold the ball in a fixed position.
Pressure absorption
Line pressure generates hydraulic thrust on the ball. The trunnions absorb much of this force rather than transferring it directly to the seats.
Reduced seat loading
Because the ball remains mechanically supported, the seating force can be controlled through the seat design rather than relying only on downstream line pressure.
Low operating torque
Reduced friction between the ball and seats helps lower the torque required to operate the valve.
Reliable shut-off
Spring-loaded or pressure-energized seats maintain contact with the ball to provide sealing under different operating conditions.
Trunnion ball valves excel in high-pressure, high-reliability applications due to their fixed ball design, robust sealing, and low torque operation. Their versatility in actuation, maintenance-friendly ball valve design, and compliance with stringent safety standards make the trunnion style ball valve the top selection for critical industrial installations.
1. Design and Construction:
Trunnion-Mounted Ball: The ball is fixed and supported by upper and lower trunnions (shafts), providing stability and reducing mechanical stress.
Fixed Ball Design: The ball does not displace under pressure, unlike floating ball valves, ensuring consistent alignment.
Seat Mechanism: Spring-loaded or pressure-energized seats maintain contact with the ball, enhancing sealing reliability, available in soft seat or metal seated trunnion ball valve configurations.
2. Pressure Handling:
High-Pressure Suitability: Ideal for applications exceeding Class 600 ratings– the hallmark of high-performance industrial valves. Trunnions absorb thrust from line pressure, minimizing seat deformation.
Bidirectional Pressure Resistance: Capable of sealing against pressure from either direction due to robust seat design.
3. Safety Features:
Fire-Safe Design: Secondary metal seats and graphite seals prevent leakage during fire exposure (API 607/6FA compliant).
Anti-Static Device: Prevents spark risk from static buildup.
Blow-Out Proof Stem: Ensures stem integrity under high pressure.
The design of a trunnion style ball valve combines a fixed ball, trunnion supports, valve seats, stem, body, and sealing components into a pressure-resistant flow-control system.
The ball is mechanically supported by upper and lower trunnions rather than floating between the seats. This fixed arrangement helps maintain ball alignment during operation and reduces the mechanical load placed on the seats.
KFTE trunnion ball valves can use spring-loaded or pressure-energized seat mechanisms. Seat springs help maintain contact between the seat and ball, including conditions where line pressure is low or absent.
Depending on the valve design, soft seat and metal-seated configurations can be selected for different service requirements.
Excess pressure can potentially accumulate inside the valve body cavity when the valve is closed. A cavity pressure relief mechanism helps control excessive cavity pressure and supports the integrity of the valve sealing system.
KFTE's cast and forged trunnion ball valve designs include self-relieving seat configurations. The applicable product designs specify automatic cavity pressure relief when cavity pressure exceeds 133% of the pressure rating, with double piston seat available as an option.
The stem is designed to prevent the stem from being ejected from the valve body under internal pressure. This provides an additional safety feature for high-pressure industrial service.
An anti-static device provides electrical continuity between metallic components of the valve, helping reduce the risk associated with static charge accumulation during operation.
KFTE Trunnion Ball Valves are designed and tested for fire-safe performance in accordance with API 607 / API 6FA requirements. The valve design incorporates secondary sealing elements to help maintain isolation if the primary resilient sealing components are affected by fire.
Sealing performance is one of the key considerations when selecting a trunnion mounted ball valve.
KFTE's cast and forged trunnion ball valve designs use soft seat configurations as standard. Seat inserts such as RTFE, Devlon, or PEEK can be installed within a metal seat ring according to the product configuration.
At low or zero line pressure, seat springs help maintain sealing contact between the ball and seats. Under operating pressure, the seat design works together with the pressure conditions inside the valve to maintain reliable isolation.
For applications requiring a different sealing arrangement, a double piston seat design can also be provided as an option on applicable KFTE trunnion ball valve configurations.
1. Ball Support Mechanism
Trunnion Ball Valve:
The ball is fixed and supported by upper and lower trunnions (shafts).
The ball does not move under pressure; trunnions absorb mechanical and hydraulic forces.
Floating Ball Valve:
The ball is not anchored and “floats” between the seats.
Line pressure pushes the ball against the downstream seat to create a seal.
2. Pressure Handling
Trunnion Ball Valve:
High-pressure applications (Class 600 and above).
Trunnion mounted ball valves prevent seat deformation by absorbing thrust from the line pressure.
Suitable for bidirectional sealing (pressure from either direction).
Floating Ball Valve:
Low to moderate pressure (up to Class 300 typically).
Relies on line pressure to force the ball against the seat, limiting effectiveness at very high pressures.
Generally unidirectional sealing (seals against pressure from one direction).
Sealing Mechanism
Trunnion Ball Valve:
Uses spring-loaded or pressure-energized seats to maintain contact with the ball.
Sealing is active even at zero pressure due to pre-loaded seats.
Often uses dual-sealing systems (e.g., soft + metal seats) for fire-safe compliance.
Floating Ball Valve:
Sealing depends on line pressure pushing the ball against the seat.
At low or no pressure, sealing may weaken.
Typically uses soft seats (e.g., PTFE) for tight shut-off.
| Feature | Trunnion Ball Valve | Floating Ball Valve |
| Ball support | Fixed by upper and lower trunnions | Ball is not mechanically fixed |
| Ball movement | Remains mechanically supported | Moves toward the downstream seat under pressure |
| Pressure loading | Trunnions absorb line-pressure thrust | Pressure contributes directly to seat loading |
| Operating torque | Reduced by the fixed-ball arrangement | Generally increases as ball-to-seat loading increases |
| Typical application | Higher-pressure and demanding industrial service | Lower and moderate-pressure applications |
| Seat mechanism | Spring-loaded or pressure-energized seats | Commonly relies on ball movement and line pressure |
| Application focus | Pipelines, critical process systems, heavy-duty flow control | General industrial and process flow control |
For applications requiring higher pressure capability, lower operating torque, and stable ball support, the trunnion-mounted design provides a different operating mechanism from a floating ball valve. KFTE specifically positions its trunnion ball valves for higher sizes and pressure ratings and critical process applications.
Upper and lower trunnions mechanically support the ball, helping maintain stable alignment and reduce seat loading.
The trunnion design reduces friction and hydraulic loading between the ball and seats, helping lower the torque required for valve operation.
Trunnion ball valves are designed for demanding pressure conditions and are particularly suited to applications exceeding Class 600 ratings according to KFTE's current product description.
The trunnion ball valve design can provide double block and bleed functionality, allowing isolation of the pipeline and controlled release of trapped fluid where the applicable valve configuration supports this function.
The seat design incorporates a self-relieving function to help prevent excessive pressure buildup inside the valve body cavity.
An anti-static device provides electrical continuity between metallic valve components.
The stem construction helps prevent stem ejection under internal pressure.
KFTE Trunnion Ball Valves are fire-safe tested in accordance with API 607 / API 6FA requirements.
The applicable design and testing standards depend on the specific cast or forged trunnion ball valve configuration.
KFTE's cast and forged trunnion ball valve product pages specify the following standards:
| Item | Applicable Standard |
|---|---|
| Basic Design | API 6D, ISO 17292, BS 5351, API 608 |
| Face to Face | ASME B16.10 |
| Flange End | ASME B16.5 |
| Butt Welding End | ASME B16.5 |
| Test and Inspection | API 598 |
| Fire-Safe Test | API 607 / API 6FA |
| Fugitive Emission Test | ISO 15848-2 |
| Pressure & Temperature | ASME B16.34 |
| Sour Service | NACE MR 0175 |
These standards are listed on KFTE's current Cast Trunnion Ball Valve and Forged Trunnion Ball Valve product pages. Specific compliance and available configurations should be confirmed according to the selected valve design and project requirements.
KFTE provides different body and trim material configurations for cast and forged trunnion ball valves.
The current product configurations include carbon steel, low-temperature carbon steel, and stainless steel options. Material specifications vary according to the individual valve construction and component.
For example, KFTE's cast trunnion ball valve material table includes A216 WCB, A352 LCC, A351 CF8/CF8M, A105, A350 LF2, and A182 F304/F316 configurations for different components. The forged trunnion ball valve page similarly lists A105, A350 LF2, A182 F304/F316 and associated component materials.
Material selection should be based on the operating medium, temperature, pressure, corrosion conditions, and applicable project specifications.
Trunnion ball valves are commonly selected for industrial systems where reliable isolation, stable operation, and high-pressure performance are important.
Used for pipeline isolation and flow control in upstream, midstream, and downstream oil and gas systems.
Suitable for process systems requiring dependable shut-off and controlled operation under demanding service conditions.
Used in process pipelines where valve material and sealing configuration need to be matched to the process medium.
Applied in industrial fluid systems where reliable isolation and pressure-resistant valve construction are required.
The fixed-ball design makes trunnion ball valves suitable for pipeline applications where operating torque and reliable isolation are important.
Trunnion mounted ball valves can be selected for applications where fire-safe performance, anti-static protection, cavity pressure relief, and double block and bleed functionality are required.
Selecting the correct trunnion ball valve requires more than simply choosing the nominal valve size. The valve configuration should match the actual operating conditions and project requirements.
Identify the normal and maximum operating pressure of the pipeline. Trunnion ball valves are particularly suitable for demanding pressure applications.
Temperature affects the selection of body, seat, seal, and other valve materials. Confirm the applicable temperature range for the selected configuration.
KFTE provides both cast and forged trunnion ball valve configurations. The appropriate construction depends on the application, pressure requirements, materials, and project specifications.
Soft seat, pressure-energized, spring-loaded, or applicable double piston seat configurations should be selected according to the medium and sealing requirements.
The fluid or gas being handled affects material selection, sealing materials, corrosion resistance, and sour-service requirements.
The valve connection should match the pipeline design, such as flanged or butt-welded configurations where applicable.
For projects requiring API, ASME, ISO, NACE, fire-safe, or fugitive-emission compliance, the applicable standards should be specified before valve selection.
Depending on the application, the valve can be configured for manual or actuated operation. Operating torque and the required actuator should be determined from the actual valve configuration and operating conditions.
Industrial pipeline applications often require valve configurations adapted to specific operating conditions rather than a standard off-the-shelf arrangement.
KFTE can provide customized trunnion ball valve solutions based on project requirements, including:
Valve body construction
Body and trim materials
Seat configuration
Sealing materials
End connection
Pressure and temperature conditions
Sour-service requirements
Fire-safe requirements
Fugitive-emission requirements
Manual or actuated operation
Special project standards
For a customized trunnion mounted ball valve, provide the medium, operating pressure, operating temperature, valve size, connection requirements, material requirements, and applicable project standards so that the appropriate configuration can be evaluated.
KFTE focuses on industrial valve manufacturing and provides ball valve solutions for oil and gas, petrochemical, chemical, power, mining, and other demanding industrial applications.
The company's ball valve range includes floating ball valves, trunnion ball valves, DBB ball valves, top-entry ball valves, full-welded ball valves, side-entry ball valves, and other industrial configurations.
For trunnion ball valve applications, KFTE provides both cast and forged designs, allowing customers to select the appropriate construction according to project requirements.
The manufacturing and product range are supported by established industrial valve standards and testing requirements, while the final configuration can be adapted to application-specific material, sealing, connection, and service requirements.
KFTE Trunnion Ball Valves are fire-safe tested according to API 607 / API 6FA requirements. The applicable valve design uses secondary sealing elements to help maintain isolation during fire exposure.
The trunnions support the ball and absorb hydraulic thrust from the pipeline, reducing the force and friction between the ball and seats. This helps maintain stable operation and reduces operating torque under demanding pressure conditions.
KFTE currently provides two main configurations on this product category: cast trunnion ball valves and forged trunnion ball valves.
KFTE's cast and forged trunnion ball valve designs use soft seats as standard, with seat inserts such as RTFE, Devlon, or PEEK depending on the configuration. Double piston seat designs are also available on applicable products.
Typical applications include oil and gas pipelines, petrochemical and refining systems, chemical processing, power generation, and other critical industrial process systems.
