Ball Valves: Types, Parts, Functions and Benefits

Chapter 1: What is a Ball Valve and How Does It Work?

A ball valve is a type of shut-off valve used to manage the flow of liquids, gases, and vapors within a piping system. It operates by rotating a ball with a central bore that either permits or blocks flow. The ball is positioned between two seats and connected to an operating mechanism via a shaft. When the bore's cross-section is aligned perpendicularly to the flow direction, the valve blocks the fluid. Conversely, when the bore is aligned with the flow, the fluid passes through, with the flow rate determined by the exposed area of the bore.

If you want to learn more, please visit our website.

Ball valves are a type of quarter-turn valve along with plug valves and butterfly valves. They can be operated manually or by using an actuator. The simplest operation of a ball valve is through the use of a wrench or a lever manually turned by an operator. Torque is applied to rotate the lever arm by 900 by either clockwise or counterclockwise to open or close the valve. If the lever arm is parallel to the pipe, it indicates that the valve is open. If the lever arm is perpendicular to the pipe, it indicates that the valve is closed.

Ball valves are available in a range of designs and features to meet diverse industrial requirements. The standards and specifications for these valves can differ based on the specific industry in which they are used.

Chapter 2: What are the parts of a ball valve?

The essential components of a ball valve are as follows:

Valve Housing

The valve housing, or body, encloses all internal components of the ball valve. It provides a secure, sealed environment for the ball, ensuring accurate control of fluid flow through the valve. Typically, the housing includes inlet and outlet ports for pipe connections. It is constructed from durable materials like metal, thermoplastic, or thermoplastic-lined metal to safeguard the internal parts, guaranteeing the valve's longevity and reliability in various industrial settings.

Ball

The ball within a ball valve is a sphere with a central hole known as the bore. The bore serves as the passage for fluid flow when it aligns with the valve's flow path. If the bore is perpendicular to the flow direction, it restricts the flow. Ball valves may feature either solid or hollow balls. A solid ball maintains a consistent opening diameter, promoting smooth and constant fluid flow. Conversely, a hollow ball, with its internal cavity, allows for higher flow rates but can create turbulence and increased velocities. Hollow balls are typically lighter and more cost-effective than solid ones.

Shaft

The shaft connects the ball to the control mechanism, enabling rotation of the ball. This rotation aligns the ball with the flow path to allow fluid passage or positions it perpendicular to block the flow. The shaft includes seals like O-rings and packing rings to prevent fluid leakage around the shaft. It must be robust enough to handle the system's pressure and temperature conditions. The shaft can be manually operated via a lever or handwheel, or it may be actuated electrically, pneumatically, or hydraulically.

Bonnet

The bonnet extends from the valve housing and encases the shaft and its packing, especially in high-pressure and high-temperature applications. It may be welded or bolted to the body and is typically constructed from sturdy metal. The bonnet provides a cover for the shaft connection to the external control mechanism and can be either removable or integral to the valve body, depending on the design.

Seat

Ball valves have two seats, usually made from soft materials such as PTFE (Teflon) or elastomers. These seats create a tight seal around the ball when the valve is closed, preventing leaks by forming a barrier between the ball and the valve body. The upstream seat seals against pressure, while the downstream seat prevents leakage to the atmosphere.

Electric Actuator

Electric actuators, or motorized actuators, enable remote control of ball valves and are ideal for situations where manual operation isn't feasible. These actuators can be designed as either quarter-turn or multi-turn units. Quarter-turn actuators are suited for valves that can be fully opened or closed, while multi-turn actuators provide multiple rotations for more nuanced control.

At the core of an electric actuator is its electric motor, which drives a gear system available in various torque ranges. This gear drive connects to an output drive that operates the valve. All components are housed in a sealed, waterproof enclosure. Electric actuators are remotely controlled and can include features such as adjustable cycle times, duty cycles, and even network or databus connectivity for enhanced functionality.

In addition to electric actuators, pneumatic actuators are available and perform similar functions. These rely on an air supply, which can limit their applicability compared to electric actuators. While electric actuators tend to be more expensive, they offer greater versatility and can be adapted to a wider range of applications.

Motorized Ball Valves

Motorized ball valves provide automated control by using an electric motor to open or close the valve. These valves feature an electric actuator mounted to the valve body, which rotates 90° to control the valve's position. The actuator responds to electrical signals that dictate whether the valve should be opened or closed.

For applications requiring precise valve positioning based on flow conditions, a digital position sensor may be employed. This sensor, coupled with a microprocessor, compares the actual valve position with the desired position using feedback from an output system. The actuator adjusts accordingly to align with the input signals.

Motorized ball valves are commonly used in remote locations to control the flow of materials. They are designed to accommodate various applications and can be located at significant distances from the control point. These valves offer a practical and efficient solution for valve control, significantly reducing labor and enhancing material handling processes.

Pneumatic or Air Actuated Ball Valves

Pneumatic actuators function similarly to electric actuators but use compressed air to control ball valves. These actuators feature a housing with horizontal pistons connected to a rack and pinion mechanism, which converts the pistons' linear motion into rotary motion. The pistons are driven by compressed air, making the system straightforward, reliable, and more cost-effective compared to electric actuators.

Like electric actuator systems, pneumatic actuators have specialized mounts for easy valve installation. They operate by receiving controlled bursts of air. A solenoid, mounted on the actuator and connected via an air line, is energized by an electric current. This current moves a plunger that opens ports on the actuator, allowing air to actuate the valve.

Air actuated ball valves come with features similar to those found in electric actuated valves, including positioners, limit switches, gear operations, and speed control. While pneumatic actuators are robust and dependable, they require proximity to an air supply, making them suitable for environments where access to compressed air is readily available.

Leading Manufacturers and Suppliers

Chapter 3: What are the different types of ball valves?

Ball valves can be categorized based on their housing assembly, ball design, and bore profile.

Housing Assembly

One-Piece Ball Valve

A one-piece ball valve features a single, cast body that encases all internal components, minimizing the risk of fluid leakage. These valves are the most cost-effective and typically have a reduced bore. Welded one-piece ball valves are common but are not designed for disassembly, making them unsuitable for applications where cleaning or repair might be necessary. They are best used in environments where particle accumulation is minimal and sanitation is not a primary concern. In contrast, screwed one-piece ball valves can be cleaned, serviced, and repaired, though disassembly requires specialized tools.

Split Body Ball Valves

Split body ball valves are designed with their bodies assembled around the ball. These valves can be categorized as either two-piece or three-piece configurations:

Two-Piece Ball Valve

A two-piece ball valve features a housing divided into two sections that are assembled together. One section houses the ball and provides a connection at one end, while the other section contains the internal components and connects at the opposite end. This design is the most prevalent among ball valves. Although the two sections can be separated for cleaning, maintenance, and inspection, this process requires removing the valve from the pipe.

Three-Piece Ball Valve

A three-piece ball valve comprises a housing that encloses the internal components, with the housing sections connected and secured by bolts at each end. These ends are typically threaded or welded to the main pipe.

Three-piece ball valves are ideal for applications requiring easy cleaning and maintenance. The design allows for the replacement of seats and seals without removing the entire valve from the pipeline, which is particularly beneficial in industries such as food and beverage and pharmaceuticals, where cleanliness and product safety are critical.

Top Entry Ball Valve

A top entry ball valve provides access to its internal components by removing the bonnet from the top of the valve. This design facilitates in-line maintenance activities'such as disassembly, cleaning, inspection, and repair'without the need to remove the valve from the pipeline.

Ball Design

Floating Ball Valves

The floating ball is a prevalent design used in ball valves. In this design, the ball is suspended within the valve and can move laterally when the valve is closed. It is positioned between two seats that secure and support the ball. The ball is connected to the shaft at one end via a slot, while the other end remains free. When the valve is open, the shaft's connection at the top of the ball keeps it from moving laterally.

Sealing in a floating ball valve relies solely on fluid pressure. When the valve operates, the inlet fluid pressure pushes the ball against the outlet seat, preventing any leakage from the valve body. The fluid pressure exerted on the ball and seats is higher when the valve is closed.

Floating ball valves are known for their simple design and are typically used in smaller diameters for handling liquids and gases under low to moderate pressures. Their application is constrained by the pressure tolerance of the seats. At higher pressures, the seats may deform due to the force exerted by the ball, potentially compromising the valve's sealing ability at lower pressures. Additionally, the torque required to turn the shaft is influenced by the force needed to overcome the fluid pressure acting on the ball and seats.

Trunnion Ball Valves

In a trunnion ball valve, the ball is supported by an additional shaft at the bottom known as the trunnion. This design stabilizes the ball and restricts its movement to the axis of the valve. The ball's movement is controlled by the rotation of the valve shaft. Trunnion ball valves also include spring-loaded seats. The inlet fluid pressure compresses the springs towards the ball, creating a secure seal.

Trunnion ball valves come in a range of sizes from small to large but are generally more costly than floating ball valves. They are well-suited for high-pressure applications because they efficiently handle a wide range of pressures. The fluid pressure is distributed to both the trunnion and the seat springs, resulting in lower operating torque and enabling the use of smaller actuators.

Vented Ball Valve

A vented ball valve operates similarly to a standard ball valve, with the key difference being that the vented ball has small orifices drilled into its side. When the valve is closed, these orifices align with the outlet side of the valve. The purpose of these drilled holes is to release trapped gases that can accumulate and build up internal pressure. This feature helps prevent leaks, valve failure, and potential explosions.

Vented ball valves are commonly used in applications involving compressed air systems, cryogenic processing, and the handling of volatile liquids. They are sometimes referred to as "cryogenic valves" due to their effectiveness in cryogenic environments.

Bore Profile

Full Bore Ball Valve

A full bore ball valve features a bore diameter that matches the pipe diameter, ensuring that the flow area remains consistent. This design results in minimal flow resistance and low frictional losses, which translates to a lower pressure drop. Such low pressure drop reduces the difficulty of pumping within the system. However, because the bore diameter must match the pipe size, full bore valves require larger ball sizes and housings, making them more expensive than reduced bore valves.

Full bore ball valves are also easier to maintain and clean. In pipeline systems, a process called pigging is used for maintenance and inspection. This involves using spherical or cylindrical devices known as pigs to travel through the pipes, detecting and removing build-ups without disrupting the fluid flow. This process is facilitated by the larger diameter of full bore ball valves.

Additionally, full bore ball valves are well-suited for handling liquids with mixed solids. They help prevent the accumulation of particles that could otherwise cause blockages or separation of the mixture as it flows through the system.

Goto ERA to know more.

Reduced Bore Ball Valve

A reduced bore ball valve features a bore diameter that is smaller than the pipe diameter by one pipe size. The exact reduction is specified based on the agreement between the manufacturer and the customer. This design narrows the flow area at the outlet, which introduces frictional losses and results in a pressure drop. As the flow area decreases, the velocity of the fluid increases to maintain the same flow rate.

Reduced bore ball valves are more commonly used than full bore ball valves, particularly in applications where flow rate and turbulence are not critical concerns, and where particle build-up is unlikely. They are generally less expensive than full bore valves due to the smaller ball size and housing required. Additionally, reduced bore ball valves typically experience a smaller pressure drop compared to other types of valves.

Segmented Ball Valve

A segmented ball valve features a V-shaped notch on the ball, which provides precise flow rate control based on the ball's rotation. This design also ensures effective shut-off capability. The flow characteristics of a segmented ball valve are designed to approximate an equal percentage flow curve, meaning that the flow rate increases exponentially as the ball nears the fully open position.

Other Types of Ball Valve

Cavity-Filled Ball Valve

A cavity-filled ball valve features a seat design that fills the gap between the ball and the valve body, preventing the accumulation of trapped media or particles that could lead to contamination or blockages. This design makes cavity-filled ball valves easier to clean and maintain.

These valves are particularly valuable in industries where hygiene is critical, such as the food, pharmaceutical, and bioprocessing sectors. They are well-suited for handling solid-liquid mixtures, such as slurries, due to their effective design.

Multi-Port Ball Valve

Multi-port ball valves are designed to manage multiple fluid streams, allowing for diversion, combination, splitting, or shutting off of flows. They achieve this through a ball with either an L-shaped or T-shaped bore. While these valves can direct flow from a single inlet to multiple outlets, they do not regulate the flow rates to each outlet stream. Multi-port ball valves are versatile in combining several streams into one or redirecting flow as needed. The schematic diagram below illustrates the various flow configurations for L-shaped and T-shaped multi-port ball valves.

3-Way Ball Valve

Three-way ball valves feature three ports for capturing and directing fluid flow. The valve's core component is a metal ball with internal passages that regulate the flow of fluid or gas. As the fluid enters the valve, a mechanism rotates the ball to direct the flow through the desired port. Three-way ball valves are available in designs with either two outlet ports and one inlet port or two inlet ports and one outlet port.

These valves can be configured in L or T shapes and are capable of various functions such as switching flow direction, mixing flows, diverting streams, and stopping flow while allowing other flows to continue. When used for mixing, the valve allows fluid to enter from multiple directions and combine within the valve body.

3-Way Ball Valve

Three-way ball valves are equipped with three ports for controlling fluid flow. They feature a central metal ball with internal passages designed to manage the direction of the fluid. As fluid or gas flows into the valve, a rotating mechanism adjusts the ball to direct the flow through the appropriate port. Three-way ball valves come in configurations with either two outlet ports and one inlet port or two inlet ports and one outlet port.

Similar to multi-port valves, three-way ball valves can be configured in either an L-shaped or T-shaped arrangement. They are versatile and can perform various functions such as switching the direction of flow, mixing different flows, diverting flow, and blocking flow from multiple directions. When mixing materials, the valve allows fluids to enter from multiple directions and blend within the valve body.

Sanitary Ball Valves

Sanitary ball valves are designed to adhere to stringent cleanliness and hygiene standards, making them suitable for applications in the food, beverage, medical, and pharmaceutical industries. These valves are engineered to meet health and safety regulations that require strict control over microbial contamination, ensuring the purity of substances during processing.

The body of sanitary ball valves is typically constructed from series 304 or series 316 stainless steel. Series 304 is commonly used in hospitals and food processing due to its smooth surface and durability, which allows for repeated cleaning without significant wear. Sanitary ball valves are designed for frequent assembly, disassembly, cleaning, and reassembly to prevent microbial growth and contamination.

These valves are engineered to mitigate risks associated with biological, chemical, or physical hazards. To ensure easy cleaning and avoid contamination, sanitary ball valves avoid threaded connections. Instead, they use seals, O-rings, and seats made from inert, abrasion-resistant materials such as polytetrafluoroethylene (PTFE or Teflon).

Sanitary ball valves address the typical issue of dead spots between the ball and the seat where bacteria can grow by employing cavity-filled ball seats. These seats fill the dead space with PTFE, reducing the risk of contamination. Additionally, the surfaces of sanitary ball valves are polished to a high finish with roughness average (Ra) values ranging from 8 to 32 to eliminate peaks and imperfections that could harbor contaminants.

Chapter 4: What materials are commonly used in the construction of ball valves?

Ball valves are typically made from a range of materials for both the ball and the housing, including:

Brass

Brass, an alloy primarily composed of copper and zinc, is easily recognized by its dull yellowish to reddish hue, which varies based on zinc content. It is a popular choice for ball valves due to its strength, durability, and ability to handle high temperatures and pressures. Brass also boasts antimicrobial properties thanks to its copper content, which helps prevent microbial growth on its surface. It offers good resistance to chemicals, corrosion, and biofouling. However, brass can be susceptible to dezincification when exposed to high chlorine levels, which can lead to the loss of zinc and weaken the alloy's structure.

Brass ball valves are not difficult to fabricate because of their malleability, and they are also easy to cast and weld. They are lighter and cheaper than steel ball valves. They are also easy to assemble in the piping system. Common applications of brass ball valves are in food, chemical, and oil and gas processing, and in conveying gaseous fluids. It is also safe to use in the delivery of potable drinking water.

Stainless Steel

Stainless steel is a high-strength alloy known for its excellent corrosion resistance, achieved through its high chromium content and, in many cases, nickel. It maintains its strength and durability even under high temperatures and pressures, making it a reliable material for demanding applications.

Common grades of stainless steel used in ball valves are 304 and 316. Type 304 stainless steel contains 18% chromium and 8% nickel, while 316 stainless steel includes 18% chromium, 10% nickel, and trace amounts of molybdenum. The addition of molybdenum in 316 stainless steel enhances its resistance to chlorides and other corrosive agents.

Stainless steel ball valves are particularly advantageous in several applications. They are commonly used in swimming pools to manage chlorinated water, in industrial settings such as desalination and petroleum refining where they handle corrosive chemicals at high temperatures and pressures, and in breweries for processing wort, a reactive liquid produced during mashing.

Polyvinyl Chloride (PVC)

PVC (Polyvinyl Chloride) is a tough, rigid plastic material known for its durability and affordability compared to brass and stainless steel. While it generally has lower strength and a lower temperature and pressure rating (up to 150 psi and 140°F, respectively), PVC is resistant to corrosion and most acids, bases, and salt solutions. However, it is not resistant to aromatic compounds and hydrocarbons. PVC ball valves are commonly used in plumbing, irrigation, and water distribution systems.

Chlorinated PVC (CPVC) is a modified form of PVC that has been chlorinated through a free radical reaction initiated by UV light. This chlorination enhances CPVC's temperature resistance, allowing CPVC ball valves to handle temperatures up to 200°F. CPVC ball valves are suitable for applications requiring higher temperature tolerance than standard PVC.

Polypropylene Ball Valve (PP)

Polypropylene (PP) is a versatile, resilient, and lightweight thermoplastic derived from propylene monomer. It is known for its high resistance to many acids and bases, although its compatibility with organic compounds and solvents is somewhat limited. The material's chemical resistance diminishes at elevated temperatures, with a maximum service temperature of 82°C. PP ball valves are effective for managing the flow of various fluids, including those with different viscosities. These valves are commonly utilized in industries such as sugar production, fertilizers, chemicals, and paper manufacturing.

Glass Fiber-Reinforced Polypropylene Ball Valve (GFPP)

Glass-fiber-reinforced polypropylene (GFPP) incorporates glass fibers into polypropylene to enhance its dimensional stability, rigidity, and chemical resistance, while also reducing its thermal expansion coefficient. With a 40% glass fiber composition, the heat deflection temperature can reach up to 150°C at 264 psi. The addition of glass fibers improves the material's cost-effectiveness and enables it to withstand more demanding and severe applications.

Polyvinylidene Difluoride Ball Valve (PVDF)

PVDF (Polyvinylidene Fluoride) is a high-purity, robust thermoplastic fluoropolymer with a high molecular weight. It is produced through the free-radical polymerization of vinylidene fluoride gas. Additionally, PVDF is known for its resistance to abrasion.

This polymer offers exceptional chemical resistance, making it ideal for handling aggressive liquids and gases such as sulfuric acid, hydrochloric acid, nitric acid, hydrocarbons, fuels, and both aromatic and aliphatic halogenated solvents. It is widely used in ball valves across various industries, including water purification, wastewater treatment, and food and pharmaceutical processing, due to its resistance to biofouling and microbial film growth. PVDF is also stable when exposed to sunlight and UV radiation. The maximum operational temperature for PVDF is approximately 115°C.

Polyethylene (PE)

Polyethylene (PE) is a versatile, resilient, and lightweight thermoplastic that is the most widely used plastic. It exhibits compatibility with a range of substances, including strong acids and bases, as well as some organic compounds like oils and alcohols. As PE's crystallinity and density increase, its chemical resistance improves. PE ball valves are utilized in various manufacturing processes and are also effective in water purification and wastewater treatment. The maximum operational temperature for PE is about 60°C.

The seat in a valve is typically made from elastomeric materials, plastics, or metals to ensure a secure seal with the ball. An ideal seat material should also exhibit the following qualities:

• A low coefficient of friction
• High compression strength
• Creep resistance
• High corrosion and chemical resistance
• Compatibility with the flowing media

Common materials used for ball valve seats include:

• Polytetrafluoroethylene (PTFE), or also known as Teflon TM
• TFM
• Polyamide (Nylon)
• Polyether ether ketone (PEEK)
• UHMW Polyethylene
• Acetal
• Metals

Metal-seated ball valves are capable of enduring higher temperatures and hydraulic pressures. They are also more resistant to abrasive and corrosive fluids.

Chapter 5: What are the advantages and limitations of ball valves?

Ball valves provide numerous advantages in a range of applications, thanks to their design and operational features. Key benefits of using ball valves include:

• Quick and Easy Operation: Ball valves have a simple design, typically consisting of a handle or lever and a spherical ball with a hole through it. This design allows for quick and easy operation, making them ideal for applications where rapid shut-off or control is required.
• Reliable Shut-Off: Ball valves provide a reliable and tight shut-off when fully closed. The spherical ball with a hole aligns perfectly with the flow path when closed, minimizing the chances of leakage.
• Minimal Pressure Drop: Ball valves typically have a low pressure drop across the valve when fully open. This ensures that the flow of fluid or gas through the valve is not significantly restricted, which is important in high-flow applications.
• Durability: Ball valves are generally durable and can withstand a wide range of temperatures and pressures. They are often made from materials such as stainless steel, brass, or PVC, which resist corrosion and wear.
• Versatility: Ball valves are suitable for a wide range of fluids and gases, including water, oil, gas, steam, and corrosive chemicals. They are commonly used in industries such as petrochemical, water treatment, HVAC, and pharmaceuticals.
• Low Maintenance: Ball valves require minimal maintenance because of their simple design. With proper installation and operation, they can last for a long time without needing frequent repairs or replacement.
• Bi-Directional Flow: Ball valves are typically designed for bi-directional flow, meaning they can be used for both forward and reverse flow applications.
• Precision Control: Some ball valves are designed for precise flow control by using a V-port or characterized ball. These specialized ball valves are used in applications where accurate control of flow rates is critical.
• Reduced Friction: Ball valves have low friction compared to other types of valves, such as globe valves. This can result in less wear and energy savings in some applications.
• Fire-Safe Design: Certain ball valve designs incorporate fire-safe features, making them suitable for use in fire protection systems and other critical applications.

Users should be aware of certain limitations to maintain the optimal performance of ball valves:

• Throttling is possible in standard ball valves, but it should be sustained for a long time. When the ball valve is in a throttling position (i.e., not in a fully closed or fully opened position), the surface area of the soft seats are exposed to the hydraulic pressure during fluid flow. This hydraulic pressure causes the soft seats to erode. Hence, utilizing standard ball valves for throttling applications is not recommended.

  Standard ball valves may be used in throttling low pressure gases. Segmented ball valves may be used in limited throttling applications.

  However, advanced ball valves with modified designs or seats made from engineered materials that are suitable for throttling applications are commercially available.

  If you are looking for more details, kindly visit PE Ball Valve.

• Application is limited by the maximum allowable working temperature of the seats. For higher temperatures, metal or ceramic seats are an alternative.
• Suspended particles may build up between the body and ball, causing leakage, erosion, and valve failure. Hence, it is advised to do frequent maintenance on ball valves handling slurries and suspensions.

Conclusion

• Ball valves are shut-off valves used to allow or obstruct the flow of fluids by rotating the ball having a bore inside it by 900. They can be operated manually or by an actuator.
• Ball valves consist of the ball, shaft, and seat which are contained in the valve housing. The ball is placed between two seats and has a stem that connects it to the operating mechanism.
• Types of ball valves are classified according to their housing assembly, ball design, and bore profile. Ball valves come in many designs and features to satisfy the needs of a specific industry.
• As the housing is divided into many pieces, the cleaning and maintenance of the ball valves get easier but more expensive to acquire.
• There are different types of ball design to select from, depending on the working pressure it will be installed to.
• A smaller bore diameter has a larger pressure drop across the valve, which makes pumping difficult and more expensive. The ball may have a multiport bore which can be used for splitting and combining flow rates and diverting flow directions.
• The material for ball valves must be hard, tough, and rigid. The seats must have a low coefficient of friction, high compressive strength, and compatibility with the working fluid. However, the application of ball valves is limited by the working temperature of the seats.
• Ball valves are easy to operate and activated and offer minimal risk of leakage.
• Throttling is not advisable for ball valves.
• Proper maintenance must be done to avoid particle build-up between the ball and the body.

Who can give me a hand? I received a inquiry from UK, the content is below:

3/4" Ball valve(800#,full bore,PE×FNPT)

I know PE×FNPT is connection type,
FNPT stand for Female NPT(National standard pipe taper thread),however I don't know what's mean of PE. Who knows the abbreviate PE. Maybe they mean one end of the valve has the thread and the other end is plain end for socket welding.
This is then a drain or vent valve. Don´t know exactly, but I think it´s like a valvolet(gatevalve)with a straight piece of pipe on one side and fem.thread on the other side(for a plug) Hi,

PE stands for Plain End, which means that the end connection is a straight part (e.g. by means of a welded in Nipple or integral machined to forged body) with straight end, so no bevel machined to it.

This type of end connection specified for socket weld piping systems.

FNPT is indeed Female NPT on the other end.

Your valve is most probably a block valve before an instrument device.

Good Luck.

Hi FKE,

Thank you very much for the answer
I haven't seen this type before.
Please confirm whether is attached type.

Thanks a lot.

Kirby
KCYST VALVE  http://files.engineering.com/getfile.aspx?folder=c1-782a--bf0c-e8dec72ceefa&file=BALL_VALVE.bmp
Hi,

Yes the sketch shows the correct type. Note that the PE part must have sufficient length in order to avoid melting of the soft seats/seals and to enable execution of welding.
Normally a minimum length of 75 to 100mm will be applied.

Success. Typically I see the designation PEBFW (Plain End, beveled for weld). In the picture that was posted it just showed a plain end without a bevel. Does anyone know what someone would do for a valve with a plain end that close to the body?

David Just a guess here, but from that diagram, it looks like one can"

- tap the PE?
- undo the top bolts and swing the body down while welding?

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums? I worked in a plant that had all the small valves welded on the process end. The valve body had as part of the forging a piece about 6 pipe diameters long that was beveled for welding to a weldolet on the line. The other end was threaded for connect to instruments and such. A 1" valve was about 10" long. Dcasto,
I've seen those too, but I just can't see a use for the plain end on the picture.

Ashereng,
That may be right, but WHAT A PAIN.

David We see some of these in sour service, where the requirement is for welds off of the pipe, but NPT after that.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?