A tight closure was not always a vital requirement for butterfly valves, making them dissimilar to other valves in that sense. The introduction of elastomeric and rubber seat materials resulted in improved sealing during shut-off, transforming the butterfly valve’s role in commercial and industrial applications.
Water supply is an obvious industry utilizing these valves, but butterfly valves are also an essential component in wastewater treatment, petroleum, chemical, food and beverage applications. These valves are particularly useful in areas with limited space. They can be used in fully closed or open 90° positions, or in increments thereof to regulate flow, offering the operator a high degree of versatility.
Butterfly Valve Functionality
What is a butterfly valve?
In simple terms, it is a valve of few parts that makes a quarter-turn rotational movement to either start, regulate, or stop the flow of gas or liquid substances. These valves can be composed of metal or nonmetallic materials depending on the application and the environment in which they are installed. Butterfly valves range in size from small and lightweight to exceptionally large.
How does a butterfly valve work?
A disc, with a connected rod or stem, is mounted inside the valve body. The rod or stem connects to an external actuator which manages disc movement. When in the closed position, the disc inside the valve body is aligned perpendicular to the product flow. With a one-quarter turn, the disc moves into a parallel position, making it fully open for product flow. As the disc remains in the product flow, any movement of the disc leads to a pressure change, altering the flow through a pipe. Throttling, or managing the volume and speed of material flow, rather than having only open/close capabilities, is a particular advantage to this valve type.
Butterfly valves are operated manually using a lever, wheel, wrench, or gearing mechanism. Semi-automatic or automatic actuators are available with electric, hydraulic, and pneumatic control options.
Butterfly Valve Features
The main components of a butterfly valve are:
- Disc. The disc works as a gate that regulates or stops product flow. Butterfly valve discs have different orientations, material compositions and design variations to improve sealing, operating torque, and product flow.
- Seat. The seat provides shut-off by creating a seal between it and the disc’s edge. The disc seats and unseats to allow flow based on the movement of the stem.
- Stem. This one- or two-piece rod connects the disc to the valve actuator. The stem’s material composition varies based on the strength needed for the seat to create the seal and if the stem will immerse in the flow material.
- Actuator. Manual, semi-automatic or automatic, the actuator moves the stem for flow control.
- Valve body. The body fits in between two flanges, frequently in wafer body or lug body styles.
These features are crucial to the functions of the butterfly valve, and they ensure the following advantages:
- Easy operation for fast opening and closing
- Durability throughout frequent operational use
- Good throttling capabilities
- Simple design with few parts, resulting in cost-effectiveness
- Low fluid resistance
Butterfly Valve Applications
How are butterfly valves used? In most cases, large-volume water and slurry applications utilize these valves. You can find them in the agricultural sector for water supply. Ships also use them in large-capacity piping, including suction lines for aft ocean water.
Other common application areas are:
- Compressed gas and air services
- Processes for cooling air, gases, and water
- Vacuum operations
- Water and steam applications accompanied by high temperatures and pressures
Lumaco Betterfly Valves
As butterfly valves are easy to position and offer simple, cost-effective designs, they are a beneficial choice for multiple industries. At Lumaco, our innovative Betterfly valves are available with a variety of durable seats for full leak protection and multi-position handles for better regulation performance. Lumaco Betterfly valves are available in manual and air-actuated models; options such as electropolish and microswitch units further customize this valve to your application.