Butterfly valves

A butterfly valve is

a fitting used to control the flow of a fluid in a pipeline. To enable this process, the flow is changed by a rotatable disc in the flow cross-section. When the butterfly valve is fully open, the disc is parallel to the direction of flow. The disc is rotated by a manually operated lever in the case of smaller nominal diameters, and by a hand crank with gearbox in the case of larger nominal diameters. Translated with www.DeepL.com/Translator (free version)