läppäventtiile

Lappaventtiile, often translated as butterfly valves, are a type of quarter-turn valve used to regulate or isolate flow. They consist of a disc mounted on a rod, which rotates on a shaft. When the valve is open, the disc is perpendicular to the flow of fluid, allowing for minimal restriction. When the valve is closed, the disc is turned 90 degrees, blocking the flow.

These valves are characterized by their simple design and relatively low cost. They are suitable for a wide range of applications, including water supply, wastewater treatment, chemical processing, and HVAC systems. Butterfly valves can handle both liquids and gases, and are available in various materials to suit different media and operating conditions. Common materials include cast iron, stainless steel, and various plastics.

The sealing mechanism in a butterfly valve can vary. In some designs, the disc may directly seal against a seat within the valve body. In others, a resilient liner or seat is incorporated into the body, providing a tighter seal when the disc is closed. Their quarter-turn operation makes them quick and easy to operate, either manually with a lever or handwheel, or automatically using actuators. Despite their simplicity, butterfly valves offer good control over flow, especially in applications where some throttling is acceptable. They are generally not recommended for applications requiring extremely precise flow control or the handling of highly viscous fluids or slurries that could impede the disc's rotation.