What is the basic function of butterfly valve?

A butterfly valve is a type of quarter-turn valve that regulates or isolates the flow of a fluid (liquid or gas) within a piping system. Its basic function is to control the flow by rotating a disk, known as the "butterfly," within the valve body. Here's how it works and its basic functions:

1. Flow Regulation: The primary function of a butterfly valve is to regulate the flow of fluid through a pipeline. By turning the valve handle or actuator, the butterfly disk can be rotated to either allow or restrict the passage of fluid.

2. Isolation: Butterfly valves can also be used for isolation purposes, meaning they can completely shut off the flow of fluid in a pipeline when fully closed. This is particularly useful during maintenance or repair activities.

3. Quick Operation: Butterfly valves can be operated quickly with a quarter-turn of the valve handle or actuator. This allows for rapid adjustment of flow rates, making them suitable for applications where fast response times are required.

4. Low Pressure Drop: Butterfly valves typically have a low-pressure drop across the valve when fully open, meaning they minimize the resistance to flow and maintain efficient fluid transfer through the pipeline.

5. Simple Design: Butterfly valves have a relatively simple design compared to other types of valves, consisting of few parts such as the valve body, butterfly disk, stem, and actuator. This simplicity often results in lower maintenance requirements and costs.

6. Cost-Effectiveness: Due to their simple design and ease of operation, butterfly valves are often more cost-effective compared to other types of valves, especially for large-diameter applications.

Butterfly valves find widespread use in various industries, including water treatment, HVAC systems, chemical processing, oil and gas, and many others, where they offer reliable flow control and isolation capabilities.