Neles Series 6D API 6D Trunnion Ball Valve

Overview

Neles Series 6D is an API 6D certified full bore trunnion ball valve that the manufacturer lists under certificate number 6D-2173. It is a soft seated, piggable isolation valve for upstream and midstream oil and gas, pipelines, refineries and petrochemical plants, with a modular body, ball and seat arrangement that lets the buyer choose materials and operators to suit the application. The Neles Series 6D datasheet emphasises long-lasting isolation performance and compliance with current industry requirements for safety and emissions.

Seven Star LLC supplies the Neles Series 6D to project teams in Oman and the GCC with engineering support in Muscat, including help with actuator selection and documentation review. The valve complements the Neles Series X2 modular ball valve by covering pipeline-class full bore duty at higher pressure classes, up to ASME Class 1500, where a piggable bore and double block and bleed sealing are mandatory.

Sealing Principle

The sealing system of the Neles Series 6D is built around a spring-loaded single piston effect seat with a double block and bleed design. Inconel X-750 helical springs behind each seat keep uniform contact between seat and ball even at low line pressure, while line pressure adds to the sealing force in service. In the closed position the body cavity can be vented, which allows the seats to be tested in place and gives verified isolation for maintenance work on adjacent equipment.

Seat tightness is bubble tight with no visible leakage under full differential pressure, in line with API 6D, API 598 and ISO 5208 Rate A, and the valve is suitable for vacuum service. A self-relieving primary soft, secondary metal seat design combines double barrier O-ring or lip seals with a graphite seal for Fire-Tite performance, so that sealing continues if the soft elements are lost in a fire. The dual body seal with a primary O-ring and a secondary graphite gasket withstands thermal shocks and pressure excursions during service.

Engineering Design of the Neles Series 6D

The Neles Series 6D uses a one-piece solid, mirror-finished ball and a cylindrical full bore flow path with low resistance, so it is fully piggable and meets API 6D flow requirements. The body is made with 3 mm of added wall thickness as standard for longevity and corrosion protection, and the body and bolting comply with ASME Section VIII and ASME B16.34. Dowel pins keep bolts free of combined torsional and bending loads in the body, stem housing, trunnion and stuffing box, and a cavity vent and bottom drain port are standard.

The stem is a single-piece, internal-entry, blow-out-proof design guided by polymer and graphite thrust washers and internal bushings that handle side loading. A multi-layer stem seal gives low emission levels, and the off-centre body joint prevents pipeline bending forces from reaching the gland packing. Engineered mounting hardware with a high-strength coupler transmits torque to gear operators or actuators, with optional API 6DX compliance, and a lifting hook with a mounting stand supports safe handling. Sizes run from NPS 2 to NPS 24 (DN 50 to DN 600).

Key Features

The Neles Series 6D brings together pipeline-grade isolation features:

• API 6D certification and bubble-tight shut-off to API 598 and ISO 5208 Rate A give confidence for custody and pipeline isolation.
• Full bore, piggable design provides maximum flow capacity for each nominal size and lets cleaning and inspection pigs pass through.
• Double block and bleed seats with cavity venting allow in-line seat testing and positive isolation.
• Fire-Tite performance is achieved through a primary soft, secondary metal seat design with graphite sealing, tested to API 607 and ISO 10497.
• ISO 15848 Class AH fugitive emission performance is supported by a multi-layer stem seal and online gland packing replacement.
• Pressure classes from ASME 150 to 1500 cover everything from refinery isolation to high-pressure gas transmission.
• Emergency seat and stem sealant injection options and an anti-static arrangement between ball, stem and body support safe operation in hydrocarbon service.
• SIL 3 capable design allows use in emergency shutdown, ESV and HIPPS loops when combined with a suitable actuator and control package.

Industrial Applications

Typical applications named in the catalogue are hydrocarbons, upstream and midstream oil and gas, pipelines, refinery and petrochemical plants, emergency valves for ESD, ESV and HIPPS, and other general process industries. In Oman these correspond to wellhead and gathering line isolation in the interior, export pipelines to the coast, tank farm and terminal isolation in Sohar and Duqm, and gas-handling plants in the Salalah region where a valve must be piggable and fire safe.

Seven Star LLC supports operators and EPC contractors by checking the Neles Series 6D against the line specification, confirming the pressure-temperature rating of the selected seat and body materials, and coordinating actuator and positioner selection. Buyers who also need a heavier trunnion valve for control or high-cycle duty can compare it with the Argus FK76M trunnion mounted ball valve or request the Neles Series 6D datasheet, or look at the Velan Memoryseal cryogenic top-entry ball valve for low-temperature duty, to review materials, port types and seat codes alongside the project piping class.

Technical Specifications

Core data for the Neles Series 6D is summarised below from the manufacturer catalogue. Temperature limits depend on the sealing material and pressure class selected.

Request a Quote for Neles Series 6D

To request a quotation for the Neles Series 6D, send Seven Star LLC the line size, pressure class, body material, design temperature, fluid, sour service requirement and the intended operator. We supply the Neles Series 6D with engineering support in Muscat and can share the Neles Series 6D datasheet and certification documents with engineering and procurement teams in Oman and the GCC.