The Trunnion mounted ball valve has adequate backing for the ball. The support is in shape similar to a shaft, and it’s called a trunnion. The Trunnion soaks up any additional pressure coming from the flow, thereby lowering the pressure on the valve seat and the ball. Trunnion mounted ball valve finds their use in large-scale implementations that require low operating torque.

Trunnion mounted ball valve structure introduction

Trunnion mounted ball valve is a new generation of high-performance ball valve, suitable for long - distance pipeline and general industrial pipeline, its strength, safety, environmental resistance and other special considerations in the design, Trunnion mounted ball valve is suitable for a variety of corrosive and non-corrosive media.Compared with the floating ball valve, the fluid pressure in front of the sphere of all is passed to the bearing force, Trunnion mounted ball valve will not make a sphere to the seat to move, so the seat of Trunnion mounted ball valve will not bear too much pressure, so Trunnion mounted ball valve torque is small, the seat of the small deformation, stable sealing performance, long service life, applicable to high pressure, large diameter.Advanced spring-loaded pre-seat assembly with self-tightening features for upstream sealing.Each valve has two seats and can be sealed in each direction, so the installation has no flow restriction and is bidirectional.

Trunnion mounted ball valve has two block type and three block type body structure, the middle flange is bolted, the seal is made of reinforced teflon inset into the stainless steel ring, there is no spring at the back of the ring to ensure the seat is close to the ball, keep the seal.There is no PTFE bearing on the upper and lower stem to reduce friction and save effort in operation. There is no adjusting plate at the bottom of the shaft to ensure the connection between ball and seal ring.Full size: Trunnion mounted ball valve flow aperture is the same as the pipeline diameter for cleaning.
 
Suitable medium: water, gas, oil, natural gas and caustic medium.
Applicable temperature: -196 ~ 350℃
Driving mode: manual, pneumatic, electric, hydraulic, etc.
Nominal diameter: DN25-800,1" ~ 32"

How does a Trunnion mounted ball valve work?

The ball of Trunnion mounted ball valve is fixed and supported by two fixed shafts connected to the ball.When Trunnion mounted ball valve closed, there is no displacement of the ball due to the pressure of the medium. The upper and lower shafts connected with the ball are usually equipped with rolling bearings or sliding bearings.In order to reduce the opening and closing of the journal friction.Reduce operating torque.Trunnion mounted ball valve is suitable for large diameter ball valves.The ball of hard sealed Trunnion mounted ball valve is fixed by upper and lower stem.During operation, the fluid pressure will not cause the ball to move towards the seat, and the seat will not be subjected to excessive pressure and deformation.The stem is provided with self-lubricated bearing to reduce friction, the switch has small twist distance, and both seats are pretightened with spring.The sealing is made of polytetrafluoroethylene inserted into the steel solid, and the rear of the steel ring is provided with a spring to ensure that the seat is closely attached to the ball.When the pressure in the valve chamber rises abnormally beyond the spring jacking force, the Trunnion mounted ball valve seat falls back away from the ball to achieve automatic pressure relief effect, and the seat is automatically restored after pressure.The advanced structure makes the sealing performance of Trunnion mounted ball valve stable and labor-saving, and the service life is long. Trunnion mounted ball valve is extremely suitable for the long transmission pipeline and the general
pipeline.

Trunnion Mounted Ball Valve Structure Introduction

The Trunnion mounted ball valve has a structure similar to the traditional ball valves seen around. The difference it brings is that the ball valves have more mechanical anchors to support the ball. The ball is given solid support from the two ends on its x-axis. It holds it in place and makes it very easy to control.

In the trunnion mounted ball valve, the design comes with dismal tended shafts at its top and bottom, which are mechanically supported. With this, it is made suitable for larger diameters and higher pressure. In the Trunnion mounted design, the ball is kept in position by compressing the seat rings at the two ends.

The ball, for its flexibility, enables a good measure of movement. While in use, it floats moderately downstream towards the seat ring to make a sealing. If the loads on the floating ball are much higher, the seat rings won’t be able to give the needed support to the ball. This is when the power of the trunnion comes in. In a trunnion design, the seat rings are the parts floating against the traditional design where the ball floats.

Body

The trunnion mounted ball valve’s body is the casing that holds it in place and offers support to the interior of the ball valve. The material for this design can be made of different products depending on the type of application it is used for. Some of the commonly used materials are carbon steel, low-temperature carbon steel, stainless steel, duplex, Inconel, and super duplex.

Ball

This is a sphere ball shaped disk through which it rotates to stop or start flow in a solid rotational motion. It is connected to the Trunnion at one end and the stem at the other end. The ball is fixed in a position while it rotates. The trunnion ball valve’s seats are often in contact with this ball, which reduces the torque.

Seat

The seat of the Trunnion ball valve is a design feature that surrounds the ball. When the actuator gets turned on, the seats keep the ball tightly in place, blocking off access. There are two types i.e. metal or soft (Teflon). This makes it move in the direction of the ball.

Trunnion

There is an extra shaft in the trunnion ball valve that grips the ball in position from beneath. This simple shaft is the Trunnion. Its function is to keep the ball firmly attached. Sometimes, the Trunnion is an extension of the spherical ball, whereas, in other trunnion mounted ball valves, it is attached to the spherical ball disk via welded joints.

Stem

The stem of the trunnion ball valve helps connect the ball and the actuator together. It is connected to the ball an additional shaft that helps secures the ball in place. Also, it regulates the ball’s movement. Trunnion mounted ball valves have strengthened anti-blowout stems, which is why they are able to handle pressurized and intense temperatures without causing any damage.

Injection

Injection fittings are designed in the seat and stem area. When sealing is compromised, and leakage is caused, the grease can be injected via a sealant injection fitting. The injected sealant functions as a partial seal to stop further leakage.However, it must be noted that the sealant injection fittings are for emergency purposes only.

Trunnion Mounted Ball Valve Structure Feature

1. Unique seat sealing structure
Trunnion mounted ball valve seat is designed with a front seal design, which has a two-way seal and an automatic pressure relief function in the middle chamber.The sealing seat inlaid with sealing material is floating and it is made of shells Spring loading ensures that the sealing surface is in close contact with the ball at all times to ensure that the valve can achieve leakage sealing under high and low pressure differences.
2. Automatic pressure relief structure
When the pressure in the middle cavity rises abnormally, the Trunnion mounted ball valve with single sealing structure has the automatic pressure relief function, while the ball valve with double sealing structure has the additional on the body Pressure relief device to relieve pressure.
3. Sealed emergency rescue function
Trunnion mounted ball valve is designed with an auxiliary seat emergency sealing system.Once the sealing surface is damaged, the corresponding sealant can be injected through the auxiliary sealing system for emergency rescue, the seat area can also be washed and lubricated through the auxiliary system if necessary.
4. Anti-static device
When operating Trunnion mounted ball valve, electrostatic charges are generated and accumulate in the ball row due to friction between the ball seats.In order to prevent the generation of electrostatic sparks, especially on the Trunnion mounted ball valve Set anti - static device, the generated static export (please contact our salesman for details).
5. Fire safe structure
Trunnion mounted ball valve seat with a unique structure, in case of fire, non-metallic sealing material burned, the metal ring with the spring of the spring to push the seat Seal with sphere to prevent fire spread and media outflow.(fire resistant structures are designed in accordance with API607, JB/T6899 and BS755)
6. Full bore structure and reduced bore structure
In order to meet the needs of customers, we has full bore Trunnion mounted ball valve series and reduced bore Trunnion mounted ball valve  series, full bore ball valve pipe diameter and pipe diameter consistent, easy to clean, etc.Reduced bore ball valve is light weight, its fluid resistance is only a part of the same diameter globe valve, the prospect is relatively broad.
7. Relief device of ball valve body
Discharge valves can be installed on the body of the ball valve according to the requirements of customer installations.Once both ends of the valve are closed, the overstock in the Trunnion mounted ball valve chamber is vented through the valve body's drain valve.
8. Extended stem device (optional)
For the buried Trunnion mounted ball valve, the extension device can be provided, including stem, grease valve, discharge valve, etc.Extension height (length generally refers to the distance from the center of the Trunnion mounted ball valve passage to the center of the operating device)

Trunnion Mounted Ball Valve Material For Different Parts

Typical materials for trunnion mounted ball valve design include:

A. Body/Closures – F304L, A105, A182 F304, F316, F51, F316L, F53, A350 LF2, LF3, Inconel, Monel, Hastelloy(Forging), A351 CF3, A351 CF8, A216 WCB, A351 CF3M, A351 CF8M, A890 4A/ 5A, A352 LCC/ LCB (Casting)

B. Ball- CS+ENP, F304L, F316, A182 F304, F316L, F51, CS+TCC, CS+Ni60, F53

C. Seat retainer- A182 F304, CS+ENP, F304L, F316, F51, F53, F316L, CS+Ni55, CS+TCC

D. Stem – A182 F51, A182 F6a, A182 F316, 17-4PH

E. Packing- RPTFE, Graphite, PTFE
 

SEAT MATERIAL

PTFE: Virgin PTFE is by far the most commonly used sealing material of exceptional quality. It has attributes suitable for most services. It’s of outstanding chemical resistance across the valve and also has low friction coefficient.

RPTFE: RPTFE (known as Reinforced PTFE) is usually created by adding 15 percent of fiberglass to virgin PTFE. It has improved pressure-temperature capabilities than the virgin PTFE and comes with enhanced wear resistance. It is effective against deformation when on load.

PCTFE: PCTFE is a chlorotrifluoroethylene homopolymer with high tensile stress and have a low deformation when on load.

Nylon 6: Nylon is a rising seat material for Valves of Class 600. It is extremely robust and can be useful in oil, air, and other media. It is appropriate for strong oxidizing agents.

Devlon: Devlon is a strong molecular weight polyamide especially suited to high temperature and pressure applications in the gas and oil industry. In addition, it is a minimal moisture absorption material.

PEEK: PEEK is an advanced high-performance thermoplastic. It is really good at continuous exposure to hot water and chemicals owing to its high resistance.

PPL: PPL(Polyparaphenylene) is an exceptional seat material which has a low coefficient of friction. It can withstand extreme pressure and also temperature resistant.

TFM: TFM (modified PTFE) is an improved chemical-modified PTFE design with improved properties whilst retaining the proven benefits of conventional PTFE.

Metal: Metal (typically stellite) seats are employed in situations of hydraulic shock, flashing abrasive media, and in extreme situations.
 

O-RINGS MATERIAL

NBR Buna-N: NBR Buna-N (NBR) is a durable and all-purpose polymer of hard water, oil, solvent, and hydraulic fluids.

HNBR: HNBR (Hydrogenated NBR) can be compared to NBR in terms of media stability but comes with much better oxidation and heat stability.

Viton: Viton (fluorocarbon) is an elastomer of fluorocarbons that is compliant with a wide variety of chemical Substances. It produces strong performance in mineral acids, chlorinated hydrocarbons, salt solutions, and petroleum oil.

EPDM: EPDM has good resistance to abrasion and tear, with outstanding chemical resistance to a range of alkaline and acids. This is susceptible to oil, strong acids, and strong alkaline and should not be applied in compressed airlines.

FVMQ Fluorosilcione: FVMQ Fluorosilcione is a fluorinated side-chain silicone polymer chain for better oil resistance. The physical and mechanical properties closely mimic those of silicone.
 

These and many more some of the typical materials used for the design of the trunnion mounted ball valve.

Trunnion Mounted Ball Valve Classification

Based on Body Configuration

The body configuration features tell how a ball valve can be used and the ease of repairs and maintenance. Based on these parameters, three types of trunnion ball valves will be examined:

Side Entry Trunnion Ball Valve

This type of design is also referred to as the split body trunnion mounted ball valve. It assembles its ball from the side. They are often made out of forged metal. In this design, the body is often divided into three or two pieces that are joined together like extensions. A piece of the body is most often bigger than the rest of the design. This larger piece holds the stuffing that winds around the ball and the ball itself. For this design, they are easily repairable and can be inspected as the smaller piece can be pulled out to access the valve.

Advantages
The design reduces defects commonly associated with a casting design
They are simple and easy to construct
They are easy to repair
Their trim mechanisms are very easy to align
They offer the advantage of reliable performance, compact envelope, and a cost-effective solution.
They are widely used and so should be readily available

Disadvantages
Could be hard to clean
Throttling causes the partially exposed seat to rust

Top Entry Trunnion Ball Valve

This trunnion valve is a unique design that assembles the ball from the top. They are mostly made from casting metal.

The ball valve is designed with a removable bonnet cover atop the ball valve. The interior parts can be accessed easily by removing the bonnet. The valves are easy to disassemble and assemble. The maintenance and repair of the trunnion ball valve can easily be done by pulling it out from the pipeline.
Advantages
The construction requires minimal thread connection
Offers an easy structure
Comes with a small volume
It is lightweight design
Offers reliable sealing
Offers easy maintenance
Gives easy access to other internals of the valve
It minimizes leak paths

Disadvantages
Possess poor regulating and throttling capabilities due to its design for shutoff and not flow modulation.
It is prone to cavitation

Welded body trunnion mounted ball valve

This design is mainly an application for the transmission of gas in buried pipelines. They are larger sizes of about up to 60 inches. They have medium pressure classes as much as ASME 900 psi. The RAM material for the design can either be centrifugal casting or forgings. They are made of a variety of materials, including martensitic SS and carbon steels. The valves major technical features include anti-blowout stem and a valve seat design accessible in three various design patterns of:

• DPE (Double Piston Effect): here, the seat may be energized by either upstream pressure or via body cavity pressure.
• SPE (Single Piston Effect): In this design, the seat can be energized by upstream pressure and no other.
• DUAL (SPE upstream and DPE downstream): It combines the two-seat designs described above. A double blockade can be guaranteed in case of failure of seat sealing.

Advantages
Has compact built and lesser weight
Has fewer leak paths

Disadvantages
Hard to carry out maintenance for the valve where installed

Based On Bore

A bore in a ball valve is the hole present in the ball’s center. There are two types of this design for trunnion ball valves based bore size.
 

Full Bore Trunnion Mounted Ball Valve

In the case of full bore trunnion ball valves design, the diameter of the bore aligns with the connected pipeline. When the valve gets opened, the medium could flow with no hindrance from the bore. They are useful in areas or plants where pigging is needed.

Advantages
They are smaller size designs
They minimize pressure drop resulting from reduced port valves

Disadvantages
They are heavier
They are more expensive

Reduced Bore Trunnion Mounted Ball Valve

A reduced bore valve is a design that has a bore size lesser than the connected pipeline’s diameter. The flow path of the channel is limited and results in greater energy loss. They are applicable to the gas and oil industry.

Advantages
They create a pressure drop in a pipe
Are smaller in size
Have a low cost

Disadvantage
The hollow ball can trap fluid when in a closed position.

Based on Sealing Material

A ball valve comprises two styles of the seat, soft seated, and the metal seated. Soft seat trunnion ball valves are seated using a thermoplastic material such as PTFE and Devlon. Metal seated ball valves make use of metals as seat material like Inconel and Hastelloy. The type of ball valve seat has its own feature and thus has its own advantages and disadvantages.
 

Soft Seat Trunnion Mounted Ball Valve

Soft seats are typically constructed of thermoplastic substances such as PTFE. They are great for environments where chemical compatibility is necessary and the environment where the tightest seal is essential.

Nevertheless, soft seats should not be used in dirty or abrasive liquids. Under such conditions, soft seats may break down, leading the valve to leakage.

Advantages
Good for clean fluid services

Disadvantages
Not suitable for abrasive media

Metal Seat Trunnion Mounted Ball Valve

The main difference between metal seated valves as against the soft seated trunnion ball valves is its ability to survive high temperatures and harsh service conditions. They can withstand severe hydraulic shock, flashing, abrasive process fluid, and higher temperatures up to and above 1,000 ° F. They are also suitable for use in high corrosion or erosion applications.

Advantages
Excellent corrosion and wear resistance.
Lower torque rate.
Tight shut-off and smooth control.
Stability under pressure and wide range of temperature and pressure.
Can withstand harsh and slurry liquids

Disadvantages
Not field repairable
Heavy design
Have a high leakage rate.

Based on Body Structure

The valve body of a trunnion ball valve can have one or more pieces joined together through welded joints. There are two kinds of trunnion ball valves based on its number of pieces.
 

Two Pieces Split Trunnion Mounnted Ball Valve

This valve comes with two pieces of the casing that are attached to each other via threaded connections. One piece of the casing can be easily opened to reach the valve for repair or cleaning. However, the valve must be separated from the pipeline; then, the covering can be installed.

Three Pieces Split Trunnion Mounted Ball Valve

The three-piece trunnion ball valves are a step ahead of its two-piece version. They’ve got three bits of the casing that are bolted together. You should remove one section to access the inside of the valve for maintenance and repair. However, there is no need to disconnect the valve from its pipeline to remove it for maintenance.

Based on Body Material

Forged Trunnion Mounted Ball Valve

Forged steel trunnion mounted ball valve is made using a ‘forging’ process. Forging is based on thermal energy being applied to solid steel blocks and then using mechanical forces to further process the steel into a finished product. This method is used to produce extremely solid and hard-wearing valves. SIO Forged Steel Valves, for example, are used in mining and mining processing, agriculture and livestock handling, aeronautics, automotive industry, brickworks, stormwater plants, rendering plants, asphalt plants, power and water industries, pharmaceuticals, chemical industry, cosmetics industry and more.

Advantages
Have uniform dimensional tolerance and thickness
Have high intensity and integrity
Have acceptable directional flow path

Disadvantage
Comes with a higher cost

Casting Trunnion Mounted Ball Valve

Casting is a kind of molding by injection, pouring molten liquid metal into the prepared mold. After refrigeration, it shapes castings. Technically, casting can be categorized into sand casting, pressure casting, investment casting, shell casting, casting without a cavity, casting with low pressure, casting with gravity, etc.

Valve casting means that the parts, including frame, and bonnet are cast. Unlike forging, casting makes use of liquid metal to produce valves. Casting is effective in making valves with complex sizes, patterns, and shapes.

Advantages
Are easy to manufacture in complex designs
Comes in lower cost than forged valves

Disadvantages
Susceptible to inter granular corrosion
Have Porosity issues
Suffer sand pockets defects
Suffer stress weakness in high proportion

Top Trunnion Mounted Ball Valve Manufacturer and Supplier

Burkert Fluid Control Systems, headquartered in Ingelfingen, Germany, is one of the world's leading  Trunnion mounted ball valve manufacturers of measurement and control systems for liquids and gases. Their product portfolio includes a number of process and control valves including ball valves.

Cameron – Schlumberger is a global Trunnion mounted ball valve manufacturer serving the oil & gas industry and offers pressure control products, rig equipment, measurement instruments, and valve products such as ball valves, butterfly valves, check valves, and gate valves. They are headquartered in Houston, TX.

Crane Co., headquartered in Stamford, CT, is a global Trunnion mounted ball valve manufacturer that operates in fluid handling, payment & merchandising technologies, aerospace & electronics, and engineered materials. Crane’s Fluid Handling segment is a global provider of industrial fluid control products and systems, including valves, pumps, lined pipe, and instrumentation.

Emerson is a global Trunnion mounted ball valve manufacturer whose automated solutions division offers a variety of valves, actuators, regulators, and fluid control & pneumatic products. The company is headquartered in St. Louis, MO.

Flowserve, located in Irving, TX, is a global Trunnion mounted ball valve manufacturer of fluid motion control solutions for industries such as Oil & Gas, Chemicals, Power, Water, and general industrial uses. Their valve products include ball valves, butterfly valves, gate valves, globe valves, check valves, plug valves, as well as linear and rotary control valves.

Kitz Corporation, headquartered in Chiba, Chiba, Japan, is a global Trunnion mounted ball valve manufacturer of valve products including Gate, Globe, Check, Butterfly, Ball Valves and Strainers, as well as Pneumatic and Electric Actuators for Valves.