Trunnion Mounted Ball Valve




The Flow Control Group supply a complete range of Trunnion Mounted Ball Valves for a wide range of applications in the water, wastewater, oil and gas and industrial process sectors.

The specification and selection of a valve and its operating protocols is essential to the optimum performance of any valve. The Flow Control team have the knowledge and expertise to identify the correct valve for the desired application.

Trunnion mounted ball valves provide tight shut-off in larger, critical, high-pressure operations and specialized low-pressure applications. The seats of the valve are always in contact with the ball making for tighter seals that prevent leakages.

Trunnion mounted ball valves are extremely versatile. They are used in many different kinds of industries because of their customizable features. For example, SIO Trunnion Mounted Ball Valve features O-rings and fire-safe stem packaging that prevent leakages. It also comes with stainless steel sealant injection fittings for emergency stem or seat sealing. Trunnion mounted ball valves are used widely in chemical, petrochemical, oil and gas, LNG, hydrocarbon industries. 

They are also used for many different kinds of applications including skids like turbine, compressor, generator, and separator, field gas, polymer, LNG, crude oil, and industrial gas processing plants, tank farms, automated process applications, hydrocarbon processing, and oil refinery feedstock lines. Trunnion mounted ball valves are suitable for both large scale high-pressure applications and compact, low-temperature situations. 

Trunnion mounted ball valves are quarter-turn valves used to stop the flow of medium in pipelines. These valves feature a round or spherical disk in the center that rotates to start or stop the flow. This disk is called a ball and it features a hollow center. Ball valves are extremely versatile and are commonly used in industrial applications where tight shut-off is required.

Trunnion mounted ball valves feature additional support for the ball. This support is in the shape of a shaft and is called a trunnion. The trunnion absorbs any added pressure from the flow, reducing stress on the ball and seats of the valve. Trunnion mounted ball valves are used in high-pressure, large scale applications where low operating torque is required. 

Types of Trunnion Mounted Ball Valves

Trunnion mounted ball valves are available in many different configurations. They are highly customizable so you can choose the size, type, and actuator that suits your needs.

Based on Body Configuration

Body configuration determines how a valve can be accessed for maintenance or repair. There are two types of trunnion mounted ball valves based on body configuration.

Top Entry Trunnion Mounted Ball Valve

This type of ball valve has a removable bonnet cover on the top of the valve. The internal parts of the valve can be easily accessed by removing the bonnet. These valves are easy to assemble and disassemble. You can repair or maintain different parts of the trunnion valve without removing it from the pipeline. 

Side Entry Trunnion Mounted Ball Valve

Side entry ball valves are also known as split body trunnion mounted ball valves. In these valves, the body is divided into two or three pieces that are bolted together like flanges. One piece of the body is always larger than the rest. The larger piece holds the ball as well as the stuffing that goes around the ball. These valves are easier to inspect and repair as the smaller piece can be removed to access the valve. 

Valve Bore

The bore of the valve is the hole that is found in the middle of the disk or ball. Trunnion mounted ball valves have two types based on bore size.

Full Port Trunnion Mounted Ball Valves

In full bore valves, the size of the diameter of the bore matches that of the connected pipeline. When the valve is open, the medium can flow freely without restriction through the bore. This type of ball valve is used in chemical, petrochemical, and refining industries. They are also used in applications where pigging is required. 

Half Port Trunnion Mounted Ball Valve

A half port trunnion valve has a bore size that is a few nominal sizes less than the diameter of the connected pipeline. The flow path of the medium is restricted which results in higher energy losses. Half port valves are mostly used in the oil and gas industry.

Valve Assembly

The body of the valve may have one, two, or three pieces connected together though welded joints. There are two types of trunnion mounted ball valves based on the number of pieces.

Two-Piece Trunnion Mounted Ball Valve

This valve features two pieces of housing that are connected to each other through threaded connections. It is easy to open up one piece of housing to access the valve for cleaning or repair. However, the valve has to be disengaged from the pipeline before the housing can be removed. 

Three-Piece Trunnion Mounted Ball Valve

Three-piece trunnion mounted ball valves go one step ahead of the two-piece design. They have three pieces of housing that are bolted together. You can remove one piece to access the inner parts of the valve for repair and maintenance. But you don’t need to disengage the valve from the pipeline to do so. 

API 6D monogrammed – Class 150 – 2500

Sizes 2″ to 24″ – Full and reduced bore

Flanged and butt welded – Firesafe to BS 6755

Carbon / Stainless Steel – Duplex / exotic alloys

Cryogenic design – Double block and bleed

Soft and metal seated – Side and top entry

Trunion Mounted Ball Valve


    OperatinG Manual



      Unit 1 Mount Street Business Park
      Mount Street Nechells
      West Midlands
      B7 5QU

      Tel: 0121 752 8870

      Oil and Gas Division

      Cooper Drive
      Springwood Industrial Estate
      Braintree Essex
      CM7 2RF

      Tel: 01376 321211

      Industrial Process Division

      Cambridge Mills Cambridge
      Nr Dursley
      GL 2 7AA

      Tel: 01453 826612