Perhosventtiili

Perhosventtiili, known in English as a butterfly valve, is a type of quarter-turn valve used to regulate or isolate flow. Its primary component is a disc mounted on a central rod. When the valve is in the open position, the disc is rotated 90 degrees so it is parallel to the flow stream, allowing for minimal obstruction. In the closed position, the disc is rotated 90 degrees to be perpendicular to the flow, blocking the passage.

Butterfly valves are characterized by their simplicity, compact size, and light weight, making them suitable for large pipe diameters. They offer a relatively low pressure drop when fully open. The mechanism of operation involves a stem passing through the valve body, with a disc attached to its end. Rotation of the stem, often via a handle, lever, gearbox, or actuator, turns the disc.

Due to their design, butterfly valves are not always ideal for applications requiring a bubble-tight seal or precise flow control at very low flow rates. However, their ease of operation and cost-effectiveness make them a popular choice for many industrial applications, including water treatment, HVAC systems, and chemical processing, where they are used for on-off service or throttling. Materials for butterfly valves vary widely, from cast iron and stainless steel to specialized alloys, depending on the service conditions and the fluid being handled.