Flange, also known as a flange disc or raised rim. A flange is a component that connects two shafts or serves as a connection point for pipe ends; it is also used at equipment inlets and outlets for connecting two devices, such as a reducer flange. Flange connection or flange joint refers to a detachable joint consisting of a flange, a gasket, and bolts, all interconnected to form a combined sealing structure. Pipe flanges are the flanges used in piping installations; on equipment, they refer to the inlets and outlets of the equipment. Flanges have holes and bolts that secure the two flanges together. They are sealed with a gasket. Flanges come in threaded (screwed) connections, welding flanges, and clamp flanges. Flanges are always used in pairs; low-pressure piping can use threaded flanges, while pressures above four kilograms require welding flanges. Two flange discs are joined with a sealing pad and then bolted together. Flanges of different pressures have different thicknesses and require different bolts. Pumps and valves, when connected to pipes, have corresponding flange shapes for these equipment components, also known as flange connections. Any connection piece that uses bolts to connect two flat surfaces around the perimeter and seals them is generally called a "flange," such as the connection of ventilation pipes. These types of components can be referred to as "flange-like parts." However, such a 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-like part." Smaller components like valves can be referred to as "flange-like parts."