The butterfly valve’s design helps advance processes in many industries. This article will teach you what a butterfly valve is, its design, and how it works.
Butterfly valves are a line of quarter-turn rotational valves used to shut off flow.
In other words, a butterfly valve is a tool that regulates the flow of materials in a large pipe by rotating a disc. They are used in various techniques, media, water supply, and pumping stations. Butterfly valves have critical advantages over other valve types: lighter weights, & lower cost.
A rod feeds through the disc center and is connected to an actuator. The disc position is either perpendicular or parallel to the flow of media. The disc is always in the flow, causing a pressure difference for any valve. So, in this way, the butterfly valve differs from other valves.
What Are The Characteristics Of A Butterfly Valve?
Butterfly valves have a feature in most applications, with 25% and 50%of valve travel. At low travel, they usually have a very high gain. High gain means they have a minimal change in the input signal and a huge change in output.
When operated for modulating benefit, the following are aspects of butterfly valves. A valve’s unique features may deliver an installed element due to its link with the system. Linear – Liner flow aspect means the flow rate is proportional to the amount of disk journey.
An equal flow aspect means that an exact valve journey creates similar changes in flow rate. The quick opening flow aspect implies that the flow rate by the valve is raised rapidly when the valve position is almost closed. When the valve position nears full open, the flow-rate changes lower in valve travel.
Here are some advantages of butterfly valves.
- Small fluid resistance
- Good regulating performance.
- Simple structure, small size, and lightweight
- Good sealing can be gained under lower pressure.
- Quick opening and closing
- It can be frequently operated.
- It can send mud and has the least amount of liquid accumulated at the outlet of the pipeline.
Working of Butterfly Valve
Butterfly valves work identically to other quarter-turn valves. Understanding the working way of the butterfly valve is nicely simple. It can assist you in knowing more about the elements of valves.
Butterfly valves are created with several elements. They contain the disk, body, packing, resilient seat, stem, and actuator. The resilient core is present on the body of the butterfly valve to give the proper seal. The filling offers an extra seal, even if the resilient seat is damaged.
The first or essential element is the metal disc. The metal disc is commonly known as the butterfly. When the valve is closed, the butterfly is positioned on a rod and blocks fluid passage. The butterfly rotates a quarter turn when the valve is entirely open. The path is unrestricted and helps the air or liquids to pass.
The working of the butterfly valve is very like a ball valve. The butterfly valves are most common because they are lightweight and have a quick operation. The metal disk is always in the flow because it raises the pressure drop.
You can use an actuator or handwheel to turn this disk. The valve disk receives a signal by rotating the stem to open or close the fluid flow.
Method
The working of a butterfly valve is explained by the following method:
- When the valve operator rotates the handle clockwise up to 90°, the handle shifts its rotation to the stem.
- As the stem accepts the motion of the handle, it rotates the valve disk.
- As the disk obtains clockwise rotation, it shifts and sits between the valve seats. As a result, the disc makes a perpendicular angle to the flow; due to that, it entirely stops the fluid flow.
- To open the valve fully, you must turn the handle in an anticlockwise direction up to 90°.
- As the disk goes to anticlockwise motion by the handle, it shifts or rotates away from the valve seat. As a result, a parallel angle formed the fluid flow and helped the fluid to flow.
- You turn the disc in half-open and close conditions for throttle flow.
Butterfly valves can also be utilized in motorcars or other systems. For example, you will see the butterfly valve inside the carburetor of an auto or other car. In this condition, the valve controls the airflow to the car’s engine. It can half open and close to adjust the amount of air passing through.
What is a Butterfly Valve Used For?
A butterfly valve controls flow by starting, stopping, or slowing, media. The disk opens and closes with a small-torque rotation of 90 ° and works for any application. Butterfly valves are favored over other types because they are lighter and cost less.
The butterfly valve resists extreme heat or extreme cold. Sealing retention is critical for high-stakes energy production and petroleum processing applications.
Common Butterfly Valve Applications
Some procedures need wear-resistant and tolerant valves with unique features. Some typical practical applications rely on the particular mechanisms of a butterfly valve.
Shut-Off Valves
As a general shutoff valve above, a butterfly valve is often the proper selection. Valves’ unique or simple design help to take up less weight and space than other valves. So, butterfly valves provide a tighter seal than a different globe valve. When closed, it is helpful to stop the fluid flow as it prevents any fluid from passing through the pipe.
Food Processing
High durability, simple design, and low care adjust fluid flow in any piping system. So, the butterfly valves help in food processing applications.
Refineries
The butterfly valve is additionally found in refineries. These would typically use the more “high end” High-Performance valve with Steel bodies and bubble tight. Many systems involving water use the resiliently seated version.
Ship Building
Butterfly valves are often used in ships where ABS-approved materials are selected because of their high durability in salt water. This type of valve makes a water-tight shutoff in the piping system of a boat to avoid any flow in the pipe. The small size of butterfly valves enables them to be used in tight spaces that are common aboard the ship.
How to Choose Correct Butterfly Valves?
The selection of the appropriate butterfly valve depends on the system’s conditions. Because of several factors, a complete system analysis is required to check correctness.
To ensure you have the suitable butterfly valve for your system, view the following factors:
Material
Butterfly valves are made of different materials, and notice how they function in your system. Valves can be metallic or non-metallic. The most typical materials for valves are carbon steel or ductile iron. But these aren’t good for erosion, so you should opt for stainless steel butterfly valves. The cost of stainless steel may be more, but it’s resistant to high temperatures and corrosion. A valve made of alloys is needed when pressure drops are extensive.
Body style
Butterfly valves can come in different styles for the requirements of piping systems. Some valves are needed to be sandwiched between two adjacent pipe flanges along the middle of a process line. These non-threaded butterfly valves are lightweight.
Type of media
Before choosing valves, it’s essential to know what fluid travels through your system: a gas, liquid, or slurry. The type of media will influence how good the valve’s seal is. Gas system butterfly valves need the lowest leakage at active temperature and pressure. Valves for liquids need a tight seal to prevent liquids from leaking.
But, the valves for solids must have a seal that contains flush within the pipe to prevent the blocking of the flow. Solids are also used to wear down the valve seat faster, making larger valves more useful for solids.
Pressure drop
Pressure drop is the change in fluid pressure between the outlet or inlet of the valve. When choosing the size of the butterfly valve needed, it is necessary to consider it. For flow regulating applications, the valve control if the pressure drop is significant. In this case, you should select a valve with a smaller opening.
Speed of orientation
Consider your working speed and system requirements before buying butterfly valves. A fast-acting actuator on your butterfly valve is needed if your system must be fast isolated or stopped. Hydraulic actuators can supply immediate action in a mixture with a solenoid valve. When the motor speed of the actuator is high, electrical actuators can also give fast actuation. Fast-acting valves are not appropriate for adjusting the flow of fluids.
If you do not need fast isolation elements, a slow-acting actuator on your butterfly valve will suit your application.
Summary
Butterfly valves are common types of valves that are lightweight and low-cost. They are the best choice for many applications and come in various styles and sizes. Hopefully, this article has guided you about the type and needs of your butterfly valves. So, you can choose the most suitable valve for your system by above mention guide.
