Why top-entry construction matters
Top entry describes body access, not the ball support system. A top-entry valve may use trunnion-mounted construction. When reviewing an RFQ, specify both requirements independently.
Maintenance and access
Confirm clearance above the valve, cover removal method, isolation requirements and serviceability of the seat system. “In-line maintenance” depends on the actual design and safe operating procedures.
Technical selection
Body and cover material, fastening, sealing, bore, temperature and pressure class should be specified. Review total valve weight, vertical envelope and access clearance on the GA drawing.
Supplier documentation
Request drawings with maintenance envelope, seat construction, torque, installation orientation and test plan for technical evaluation.
Frequently asked questions
Does top entry mean trunnion mounted?
Not necessarily. Top entry refers to access through a top cover; trunnion mounted refers to ball support.
Can the valve be serviced without removing it from the pipe?
Some top-entry designs permit certain in-line maintenance activities, subject to isolation and the manufacturer’s instructions.