What exactly are butterfly valves?
Butterfly valves are made up of a pipe wall seal, a round disc or plate, and a control lever. When the lever is turned, the valve’s disc rotates ninety degrees. The valve is open when the disc is parallel to the flow of water; when the handle is turned, the disc rotates around to a position parallel to the flow of water. It fits snugly into the seal and completely prevents all flow through the pipe. Butterfly valve manufacturers have a variety of material options when producing butterfly valves. Stainless steel butterfly valves are the most commonly used because they are naturally corrosion-resistant, efficient, and highly sanitary, and they require less maintenance than other materials.
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These valves are commonly found in water distribution pipes as well as chemical service vehicles. Cast iron butterfly valves are another material-based style that is known for its strength and durability; however, even when it is the primary material for a valve, stainless steel or aluminum is used for the gasket because it requires a light and flexible metal. Plastic butterfly valves are less expensive to manufacture but are not as common as metal valves, owing to the corrosion factor that is a common problem in piping. When compared to other types of flow devices, butterfly valves have both advantages and disadvantages. They are effective at blocking flow and do not cause leakage, but they are difficult to thoroughly clean and are thus unsuitable for sterile applications, such as those in the food or medical industries; however, sterile metals, such as stainless steel, are occasionally used. The majority of industrial companies that use butterfly valves are in the manufacturing, chemical, and water-based industries, as well as anything to do with pipes. Manufacturers can modify the butterfly valve design based on the size and shape of the pipe where the butterfly valve will be installed. Specific types of butterfly valves, as well as different types of piping connections, will be used depending on whether the environment will be high or low pressure. Flanged butterfly valves have winged and raised edges that allow them to be attached between pipes, creating a leak-resistant seal, whereas triple offset valves seal the pipe in three different places, ensuring no leak occurs. Whatever your piping requirements are, there is a butterfly valve to meet them. Butterfly Valves manufacturer Lucky6s is a Butterfly Valves manufacturer brand that produces high-quality butterfly valves in a variety of materials and configurations. Butterfly valves are rotational valves with a 90-degree turn that are useful for stopping, regulating, and starting flow. They are simple and quick to open because the quarter rotation allows the valves to close and open completely. They are a popular choice due to the thin space between the flanges, which makes them lightweight and inexpensive. Most large butterfly valves come with a “gearbox,” which makes the valve’s application simple. However, this will slow down the operation. When you buy Butterfly Valves from Lucky6s, you can be confident that you will only receive the best butterfly valves for your projects. Butterfly valves serve as control or shut-off valves. They use a quarter-turn rotational motion to regulate, start, and stop the flow of fluid. They can limit the flow by being partially open or completely closed. Butterfly valves are ideal for shutting down and throttling processes. Butterfly valves are used to regulate the flow of a fluid. The type of fluid depends on the materials used to make butterfly valves. Chemically neutral fluids, pharmaceutical fluids, and even corrosive fluids can be used. Butterfly valves have a good sealing system that makes them suitable for use in heating circuits. A disc mounted on a rotating shaft is used in butterfly valves. When the valve opens, the disc forms a right angle to the flow of the fluid. When the valve is fully closed, the disc completely blocks the line, causing the flow to be disrupted. Butterfly valves help to reduce pressure in a system by controlling the flow of fluid. When thehigh performance butterfly valves manufacturersWhen the flow of fluid through the valve’s opening is restricted, the pressure further down the pipeline drops significantly. Some butterfly valves, such as PVC butterfly valves, have a handle that stops and locks at any position as it fully opens or closes to precisely control the flow of the fluid.Some butterfly valves have flanges, which means they cannot be connected to piping right away. They are necessary in pressure drop because the valve disc is always present in the flow. Butterfly valves are used in a variety of fluid services as well as slurry applications. These valves are ideal for cooling water, gas, air, and fire protection systems, as well as vacuum and steam services.
What Are the Different Parts of a Butterfly Valve?
Body
Butterfly valves have bodies that fit between two flanges, and the most common designs are lug and wafer. The lug body uses protruding legs to provide bolts that match those in the pipe flange, whereas the wafer body is positioned between two flanges using nuts and studs or bolts. The wafer body, unlike the lug body, does not have protruding legs and is less expensive in terms of initial and installation costs.
Stem
The design of a butterfly valve stem varies. It can be a split shaft, a one-piece shaft, or a two-piece shaft. The stem provides the necessary strength to unseat or seat the disc, so its position should be precise. The stem should be compatible with the fluid because it is in close contact with it.
Seat
The disc seals against an elastomeric seat in most butterfly valves. The seat uses an interference fit connected to the disc edge to provide shutoff. The flow of fluid is stopped when the disc is sealed against a seat inside the valve body. The seat can be locked in place or pressed against the body. A line-energized seat design or an interference-fit design can provide the shutoff in high-performance designs. These designs raise the pressure in the pipeline, increasing interference between the disc edge and the seat. The temperature and compatibility of the seat vary depending on the material used in its construction.
Disc
The disc, like the ball in a ball valve, the plug in a plug valve, and the gate in a gate valve, is designed to close the valve and stop the flow of liquid. Furthermore, the disc regulates fluids such as water and chemicals. The alignment of the disc with the stem improves fluid flow, sealing, and operating torque. Through a 90-degree rotation, the disc closes or opens the valve.
What Are the Different Types of Butterfly Valves?
Butterfly Valves Classified by Valve Body Material
Carbon Steel
Carbon steel is an iron alloy in which carbon is the primary element. Carbon steel butterfly valves are inexpensive and useful for low-pressure applications. These valves are ideal for use in the food, oil and gas, chemical, and pharmaceutical industries.There are several grades of carbon steel butterfly valves. These grades are cast grades ASTM A216 WCB or Weldable Cast B-grade, which are ideal for high-temperature applications, and LCC or Low Carbon Content steels, which are best suited for low or sub-zero temperatures.
Stainless Steel
Stainless steel is an iron-nickel alloy with 10.5 percent chromium content. The addition of chromium creates a self-healing layer of oxide on the material, preventing it from rusting. The most common stainless steel classifications are ferritic, martensitic, precipitation hardenable, duplex, and austenitic. However, when it comes to valve construction, duplex and austenitic stainless steels are the most commonly used materials.When the surface of stainless steel butterfly valves is scratched, the chromium reacts with oxygen, preventing the surface from reacting with iron and rusting. As a result, stainless steel butterfly valves are highly recommended in applications requiring high corrosion resistance, such as water systems.
Nickel Alloy Steel
In terms of temperature, pressure, and fluid, nickel alloy steel butterfly valves are frequently used in severe and harsh conditions. They are designed to withstand highly corrosive environments, which are not recommended for lower grade steels, such as stainless steel materials. Extreme corrosive environments may erode the protective oxide layer that stainless steel valves have.
Titanium and Titanium Alloys
Titanium butterfly valves are well-known for their outstanding corrosion resistance and strength. Titanium alloys have the highest strength-to-weight ratio of any metal. These materials also have a protective oxide layer, which is found in stainless steel valves and protects the valves from rust.Titanium butterfly valves are highly durable because they can withstand corrosive environments such as seawater and industries that use hypochlorite.
Nickel Aluminum Bronze
Nickel aluminum bronze butterfly valves are made from a copper alloy that contains about 5% nickel, 5% iron, and 10% aluminum. They are highly corrosion resistant and thus ideal for seawater applications. These nickel aluminum bronze butterfly valves can prevent biofilm from forming, which is one of the causes of corrosion problems in stainless steel.
Ductile Iron
Ductile iron butterfly valves are made from a modern iron alloy containing nodule-shaped graphite. These valves have high ductility, which means they do not easily break when bent. Ductile iron butterfly valves are notable for their high tensile and yield strength, as well as their resistance to corrosion. Ductile iron butterfly valves have a high structural integrity, which means they can withstand high temperatures and pressures without flinching. Because of their ductile nature, these valves do not crack easily even when bent.
Cast Iron
Cast iron butterfly valves are made from a type of metal that has been used for hundreds of years. These valves are made from an alloy of small amounts of silicone, 2 to 4% carbon, and 96 to 98 percent iron, which gives cast iron butterfly valves their impressive temperature tolerance. Cast iron butterfly valves are remarkably strong because they usually remain undamaged even after being subjected to intense vibrations during operations. When compared to other plastic valves, these can withstand higher pressures.
Butterfly Valves Classified by End Connection Type
Wafer Type
Wafer type butterfly valves are installed with two or more centering holes and are frequently regarded as the lightest and cheapest option when selecting butterfly valves. Wafer butterfly valves are built with a seal to protect the valve from a dual-directional pressure differential in the fluid flow. To simplify matters, wafer butterfly valves prevent backflow in systems by maintaining a tight seal that prevents the bidirectional pressure differential from entering the valve. To protect the systems from the bidirectional pressure differential, a tightly fitted seal, such as a gasket or precision machined O-ring, is used, as well as a flat valve face on the upstream and downstream areas of the valve.
Lug Type
Lug type butterfly valves are attached to pipe flanges with a separate set of bolts for each flange. These valves are designed in the manner of a three-piece ball valve, which means that removing one end of the line has no effect on the opposite side of the line. The removal of downstream piping or dead-end service is possible with lug butterfly valves.
Butt Welded Type
Butt-welded butterfly valves are specially designed to avoid scratches and galling between the metal disc and metal seat. When the valve is completely closed, the seal only comes into contact with the seat once. Welded type butterfly valves are commonly used in applications requiring extremely high pressures and bi-directional tight shutoff, such as the petroleum, chemical, and power generation industries. These valves are also intended to prevent extrusion in contaminated or heavy oil.
Butterfly Valves Classified by Seat Type
Butterfly Valve with a Metal Seat
Butt-welded butterfly valves are specially designed to avoid scratches and galling between the metal disc and metal seat. When the valve is completely closed, the seal only comes into contact with the seat once. Welded type butterfly valves are commonly used in applications requiring extremely high pressures and bi-directional tight shutoff, such as the petroleum, chemical, and power generation industries. These valves are also intended to prevent extrusion in contaminated or heavy oil.
Soft or Resilient Seated Butterfly Valve
Soft or resilient seated butterfly valves are ideal for low pressure and non-critical applications such as the food and pharmaceutical industries. They are primarily used to regulate, stop, and start the flow of fluid in pipelines. Gears, handles, or actuators can be used to operate these valves. The stem of this type of valve is located in the center of the valve disc, which is located in the center of the pipe bore. Butterfly valves with resilient seats move the valve disc into the optimal position to close or open the valve completely. These valves typically have a rubber or resilient seat that relies heavily on contact between the disc and the seat to provide a tight seal, which typically occurs at around 85 degrees during a quarter-turn rotation.
Soft or resilient seated butterfly valves are ideal for low pressure and non-critical applications such as the food and pharmaceutical industries. They are primarily used to regulate, stop, and start the flow of fluid in pipelines. Gears, handles, or actuators can be used to operate these valves. The stem of this type of valve is located in the center of the valve disc, which is located in the center of the pipe bore. Butterfly valves with resilient seats move the valve disc into the optimal position to close or open the valve completely. These valves typically have a rubber or resilient seat that relies heavily on contact between the disc and the seat to provide a tight seal, which typically occurs at around 85 degrees during a quarter-turn rotation.
Butterfly Valves Classified by Valve Operation
Manual Butterfly Valve
Manual actuators close or open the valve by turning a crank or a handwheel. These actuators allow the user to position the valve as needed. Manually operated butterfly valves are ideal for remote systems that do not have access to power. On smaller valves, manual actuators are preferable. The handwheel on manual actuated butterfly valves is attached to a stem or hammer, allowing the valve to be pounded closed or open as needed. Gear heads are added to increase open and close speed for added mechanical advantage.
Lever Handle
Lever handle actuators are commonly used in small butterfly valves. These actuators have the ability to lock valves in an open, partially open, or closed position.
Automatic Butterfly Valve
Automatic actuators are used to remotely control valves. Larger valves can be operated quickly with the help of these actuators. Power operated actuators are designed to fail-open or stay open when the actuator fails, fail-close or stay closed when the actuator fails, and often include a manual actuation method when the actuator fails. Electric, pneumatic, and hydraulic actuators are the three types of automatic actuators.
Pneumatic Actuated Butterfly Valve
Semi-automatic and automatic pneumatically actuated butterfly valves are available. Through the air pressure in a diaphragm or piston connected to the stem, they convert an air signal into valve stem motion. Because they are fast-acting valves, pneumatic butterfly valves are ideal for open-close positioning and throttling operations.
Electric Actuated Butterfly Valve
Electric actuated butterfly valves can be operated automatically, semi-automatically, or manually. Electric actuators are one of the most commonly used types of actuators in butterfly valves because they are low-maintenance and dependable. These actuators enable remote control of electric actuated butterfly valves. Electric actuated butterfly valves, which are usually reversible, use a high-speed motor to close and open the valve. A gear train connects the electric actuators. They increase torque by slowing down the motor. The torque of the motor or the position of the valve operate electric actuated butterfly valves. A limit switch can be used to prevent the valve from fully opening or closing on its own.
Hydraulic
Hydraulic actuated butterfly valves can be fully automatic or semi-automatic. They’re made to control the flow of hydraulic fluid in a hydraulic circuit. Hydraulic actuators are frequently used to open a valve that requires a significant amount of force, such as the main steam valve. They can also be used to redirect pressurized fluid or completely close a line. Hydraulic actuated butterfly valves close using a spring force with no fluid flow pressure. As the fluid enters the chamber, it changes the pressure inside the valve. When the valve opens, the piston moves upward to accommodate the hydraulic fluid’s greater force than the spring force. As hydraulic fluid enters one side of the piston, the valve closes, and the other side is bled or drained. Hydraulic actuated valves are inexpensive and widely used in a variety of industries, including the food, pharmaceutical, and chemical industries.
Butterfly Valves Classified by Valve Operation
Zero Offset / Concentric
The most basic types of butterfly valve design are centric or concentric butterfly valves. The center of rotation in concentric butterfly valves is at the centerline of the valve disc, which is located in the center of the bore. The seat is located within the valve body’s diameter periphery. A concentric butterfly valve has a conically designed frictional interference seal between the seat and the center seal. This design works best in soft-seated valves, which rely on the flexibility of the seat rubber to efficiently seal the flow of fluid when the valve is closed. Because the seat is built as a sleeve in the valve body, the media that passes through the valve does not come into contact with the body. When performing a quarter-turn rotation, the disc makes first contact with the seat at around 85 degrees. Butterfly valves with zero offset work best in low-pressure applications.
Double Eccentric / Double Offset
Double eccentric butterfly valves, also known as high-performance butterfly valves, are widely used in the power generation, chemical, HVAC, and oil and gas industries. Double eccentric valves can withstand higher pressure and temperature conditions than zero offset or concentric butterfly valves. The two stems offset from the center of the double offset butterfly valves are responsible for creating a cam action during the application process. The sealing plane of the disc in double offset butterfly valves is offset from the axis of rotation. An annular sealing element can be used in the valve due to the position of the sealing plane, which results in a circular sealing surface on the disc. The disc’s axis of rotation is positioned to the side of the center, allowing it to move freely from the seat and prevent the valve from jamming as it opens and closes.
Triple Offset Butterfly Valve
Triple Offset Butterfly Valve, also known as triple offset butterfly valves, have three offsets. Two of them are in the same place as the double offset butterfly valve. The third offset, on the other hand, is placed geometrically to the seating surface, resulting in a cone-shaped angle of the seat and disc. These three eccentric shaft offsets create a frictionless seal between the disc and the seat. Triple eccentric butterfly valves provide a tight shutoff and consistent sealing. These valves are designed for easier automation at a low cost, and they are an alternative to metal-seated valves. Triple eccentric butterfly valves are best suited for high-temperature gases and oils, as well as high-pressure steam, where a metal seat is required and a 90-degree rotation and tight shutoff are preferred. These valves are required in high-pressure operations such as the petrochemical and power generation industries.
Butterfly Valves Classified by Sealing Material
Butterfly Valves with a Rubber Lining
Rubber lined butterfly valves are intended for use in isolating or regulating flow by utilizing rubber as the sealing material. The closing mechanism is a disc that sits in the center of the valve body and is connected to an actuator or handle via a shaft that runs through the top of the body. In comparison to a ball valve, the disc of a rubber lined butterfly valve causes a pressure drop because it is always in the flow. Rubber-lined butterfly valves, unlike ball valves, can be shut off easily and without requiring too much support because they are lightweight.
Butterfly valves with rubber linings are fully operational in a 90-degree rotation motion. These valves can also be opened incrementally to throttle flow. Manual rubber lined butterfly valves can be used to control flow, but actuated rubber lined butterfly valves provide more precision.
Rubber lined butterfly valves are lightweight valves that offer a low-cost, maintenance-free solution to high-pressure applications such as the pulp and paper industry, fuel handling systems, petrochemical processing, and HVAC operations.
Butterfly Valves with Plastic Lining
Plastic-lined butterfly valves use a plastic sealing material to regulate, stop, and start the flow of fluid. They are excellent for on/off operations, throttling, and control applications in powdery media, liquid, or gaseous service.
Butterfly Valves with Metal Lining
Metal lined butterfly valves have a metal to metal seal, allowing them to withstand high pressure and temperature conditions. Metal-lined butterfly valves are durable and wear-resistant due to their consistent sealing performance. These valves are intended for use in a variety of applications, including operations in the petroleum, fuel, and food industries, as well as systems requiring high fire resistance.
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