Choose a floating ball valve when the line size, pressure, and operating torque are manageable for a ball supported by its seats; choose a trunnion ball valve when a mechanically supported ball is better suited to the project’s pressure, size, or actuation requirements. In a floating design, line pressure pushes the ball against the downstream seat to help create shutoff. In a trunnion design, upper and lower supports hold the ball in place, while the seats move against it. The right choice depends on the complete operating envelope—not on valve type alone.
For more information, please visit our website.
At KAIWEI VALVE, we recommend comparing pressure and temperature, bore size, media, operating frequency, actuator needs, and applicable specifications before requesting a quotation. The guidance below explains the design differences, relative sourcing considerations, and practical steps buyers can use to select a suitable configuration. Exact capabilities depend on the valve’s design, materials, size, and manufacturer documentation.
Both designs are quarter-turn valves: the ball typically rotates 90° between open and closed positions. Their main structural difference is how the ball is supported and how the seats achieve contact. That difference can affect operating torque, seat loading, valve dimensions, and cost, but it does not establish a guaranteed pressure rating or service life by itself.
A floating ball valve holds the ball between two seats without a separate lower support bearing the ball’s operating load. When the valve is closed, upstream pressure can move the ball slightly toward the downstream seat, increasing contact between the ball and seat. This design is comparatively straightforward, but seat loading and operating torque can rise as pressure, size, or other service demands increase. Buyers should confirm the manufacturer’s torque data for the actual valve and operating conditions.
A trunnion ball valve supports the ball at the top and bottom, limiting its movement under line pressure. The seat assemblies, rather than the ball itself, are arranged to maintain sealing contact with the ball. By reducing pressure-driven ball movement, this design can help manage operating torque in applications where load, size, or actuation requirements make torque an important consideration. The exact seat mechanism and any pressure-relief or sealing features must be verified against the selected model’s documentation.
| Selection factor | Floating ball valve | Trunnion ball valve |
|---|---|---|
| Ball support | Ball shifts slightly between seats under pressure. | Ball is supported by trunnions and the stem. |
| Seat loading | Line pressure can increase load on the downstream seat. | Moving seat assemblies maintain contact with the supported ball. |
| Operating torque | Can increase with pressure and seat load; obtain model-specific values. | May be advantageous when torque management matters; confirm actuator sizing data. |
| Common selection context | Often considered for smaller sizes and less demanding operating envelopes. | Often considered for larger sizes or demanding pressure and actuation requirements. |
| Cost considerations | Simpler construction may support a lower initial purchase cost in suitable configurations. | More support components can affect initial cost, depending on size and specification. |
| Key checks | Pressure-temperature limits, seat material, torque, and leakage requirements. | Pressure-temperature limits, seat mechanism, torque, dimensions, and required features. |
This comparison describes common design tendencies, not universal product rules. A well-engineered valve in either category must be selected against the project’s specified service conditions. Do not use a general comparison table as a substitute for a manufacturer’s pressure-temperature rating, materials list, or technical data sheet.
Link to KAIWEI VALVE
A floating ball valve may be appropriate when its available size and pressure range match the line, and the required shutoff and operating torque can be met. Its simpler arrangement can be attractive for buyers seeking a practical shutoff solution without features their process does not require. Before choosing it, confirm the seat material’s compatibility with the process fluid and the valve’s suitability for the expected temperature and pressure. Also check whether the available operator or actuator can handle the documented torque.
A trunnion ball valve is worth evaluating when a project involves larger sizes, significant pressure loads, frequent operation, or powered actuation where torque is a design concern. Its supported ball arrangement may suit these requirements, but the complete valve still needs to meet the project specification. Confirm whether the selected model provides any requested functions, such as a particular seat arrangement or drain and vent connections. These features are configuration-specific, not guaranteed by the term “trunnion.”
Initial price is only one part of the sourcing decision. Compare the quoted scope, including body and trim materials, end connections, actuation, inspection documentation, and any required accessories. A more complex specification may affect manufacturing and delivery planning, but lead time depends on the supplier, configuration, and order conditions. Ask suppliers to state the offered model, deviations, quotation validity, and estimated delivery schedule in writing.
For clarity, a buyer might send an inquiry with an illustrative duty point of DN100, 25 bar, and 120 °C. These figures are example inputs for a quotation request, not a recommended operating limit or a rating for either valve type. The supplier must verify the chosen model against the full pressure-temperature envelope, applicable design requirements, and the process medium. Include both normal and maximum conditions where they differ.
In short, a floating ball valve uses pressure-driven movement of the ball to load the downstream seat, while a trunnion valve supports the ball and uses moving seats to maintain contact. Floating designs are often considered for simpler, smaller, or less demanding applications; trunnion designs are often evaluated where size, pressure loads, or actuator torque make ball support important. These are starting points for comparison, not substitutes for technical verification.
For your next step, prepare a datasheet with line size, pressure and temperature ranges, media, connections, shutoff requirements, and operation method. Send the same specification to suppliers so you can compare equivalent offers and review documented ratings, torque, materials, and delivery scope. KAIWEI VALVE can assist B2B buyers in reviewing these requirements and identifying a suitable floating or trunnion ball valve configuration for quotation. Contact our team with your application details to begin a technical and commercial discussion.
If you are looking for more details, kindly visit Trunnion vs. Floating Ball Valves:.