Flange, also known as a flange disc or raised rim. A flange is a component used for connecting shafts to each other, serving as a connection between pipe ends; there are also flanges used at equipment inlets and outlets for connecting two devices, such as reducer flanges. Flange connection or flange joint refers to a detachable connection consisting of a flange, a gasket, and bolts, forming a combined sealing structure. Pipe flanges are flanges used for piping in pipeline installations; when used on equipment, they refer to the equipment's inlet and outlet flanges. Flanges have holes for bolts to securely connect two flanges. They are sealed with a gasket. Flanges come in threaded (screwed) connections,焊接 flanges, and clamp flanges. Flanges are always used in pairs; low-pressure pipelines can use threaded flanges, while those above four kilograms of pressure require焊接 flanges. Two flange disks are joined with a sealing pad and then bolted together. Flanges of different pressures have different thicknesses and require different bolts. When pumps and valves connect to pipelines, these equipment components are also made in corresponding flange shapes, also known as flange connections. Any connection piece that uses bolts to connect two flat surfaces around the circumference and is sealed simultaneously is generally called a "flange," such as the connection of ventilation pipes. Such components can be referred to as "flange-type parts." However, this type of connection is only a part of a device, like the connection between a flange and a pump, so it's not appropriate to call the pump a "flange-type part." Smaller components like valves can be called "flange-type parts."