Butterfly valves are one of the most useful valves a piping system can have. They give an operator the ability to start, stop, or restrict flow in a system. This can be especially useful if repairs, cleanings, or alterations need to be made to a system and you want to ensure no fluid comes through the pipes.
Despite its name, a butterfly valve doesn't really look much like a butterfly. Butterfly valves are quarter-turn valves, meaning they go from completely open to completely closed in 90 degrees. The "butterfly" name comes from the fact that the disc, or "wings," moves around a central axis, which acts like the body of a butterfly. But there is much more to butterfly valves than the central disc.
Butterfly Valve Components
Butterfly valves are, at their most basic level, made up of a disc, seat, body, and actuator. Most have more parts than those, but they are the necessary components of a butterfly valve. The illustration below shows where each of those parts are located.
Actuator: This part is also called a handle or operator. It controls how far opened or closed the butterfly valve is. It is often a handle that moves 90 degrees, but can also be a spigot-like turning handle. On the valve above, you would squeeze the handle to operate the actuator.
Seat: The seat of a butterfly valve is usually made of some kind of rubber. It ensures that there will be a tight and secure seal when the valve is in the closed position. If a butterfly valve stops operating correctly, there is a good chance the seat has been damaged in some way.
Disc: The disc is what gives a butterfly valve its name. When the disc turns, the valve opens, giving the disc a butterfly-like appearance. The disc is moved by the actuator, and can be fully closed, fully opened, or anything in-between.
Body: The body of a butterfly valve is what enables it to be connected to pipes and fittings. It is everything around the seat of the valve and makes up a good deal of the valve's structure.
What is Actuation and Why is it Important?
Actuate literally means, "to put into action." Therefore, when you actuate a butterfly valve, you are putting it into action. The default state for a butterfly valve is closed; this allows no fluid to pass through. If you want fluid to flow through with hardly any reduction in flow pressure, you turn the handle 90 degrees to fully actuate the butterfly valve.
When people usually talk about actuation in butterfly valves, they are actually talking about automation. When a butterfly valve has to be opened to a very specific degree, you may choose to get an electrically actuated butterfly valve. These can also be helpful if your butterfly valve needs to be opened and closed frequently.
What makes these valves so valuable and different from others is that they have more than two positions. The can be opened anywhere from 0 to 90 degrees. The further they are opened, the more fluid they will let through. While some piping systems have no need for partial flow, many others do.
Gas: When regulating flow of compressed air or other gases, controlling how much gas flows through is often extremely important. Butterfly valves work just as well with gases as they do with liquids. When properly used, these valves can act as dampers to control flow so that only the specified amount passes through.
Liquid: The obvious application for butterfly valves is liquid transfer. In agriculture and manufacturing, regulating the flow of water and other liquids is vital. If you allow too much water through an irrigation system, you could over-water produce, destroying your crops. Butterfly valves allow you to choose how much or how little liquid you want to pass through a system.
In conclusion, butterfly valves have a huge amount of utility and are easy to use, even in industrial applications where specific butterfly valves made of CPVC are required. With a quarter-turn of the handle, they completely shut on or off. They also allow for partial opening, which means the operator has complete control of how much fluid passes through a system! Find this valve and many more online at PVCFittingsOnline.com