What changes inside the valve?
In a floating design, the ball can move slightly under line pressure and load the downstream seat. In a trunnion-mounted design, the ball is supported by a stem and lower trunnion; the seat arrangement provides the sealing action against the supported ball.
These are construction principles, not interchangeable model names. A two-piece or three-piece body describes how the pressure-containing body is assembled; it does not, by itself, identify how the ball is supported.
Compare the requirements that affect your order
| Selection point | Floating ball | Trunnion-mounted ball |
|---|---|---|
| Ball support | Limited movement allows pressure loading against a seat. | The supported ball works with the specified seat design. |
| Size and pressure | Check the available combination for the selected series. | Check the available combination for the selected series. |
| Operating torque | Confirm torque at the specified differential pressure. | Confirm torque for the selected seats and operating conditions. |
| Isolation requirements | Confirm sealing direction and acceptance criteria. | Confirm seat function, cavity relief and any required isolation arrangement. |
| Automation | Match the actuator to valve torque and the available supply. | Match the actuator to valve torque and the available supply. |
Which NTK series should you review?
For floating construction, review the YQ uni-body, EQ two-piece and SQ three-piece families. The BTQ / STQ page covers trunnion-mounted configurations. Top-entry and metal-seated requirements have their own product pages.
Use each series page to identify a starting configuration. The quotation should then state the exact size, pressure class, materials, seat arrangement, ends and operation. A catalogue family is not a substitute for an approved project data sheet.
What should accompany the enquiry?
- Medium, composition and any solids or contamination.
- Nominal size, pressure class, design temperature and normal operating conditions.
- Maximum operating differential pressure and cycling frequency.
- Body, ball, stem, seat and seal requirements, if specified.
- End connections, installation limits, operation and fail-position requirements.
- Quantity, required documents and delivery destination.
If the support arrangement has not been selected, say so. NTK can review the known conditions with you before confirming a configuration. Final selection needs the product-specific pressure–temperature limits, drawings and inspection requirements.
Send your requirements to NTK
Share the known conditions or attach your requirements when contacting our sales team.
Prepare an enquiry