Flanges, also known as flange discs or raised rings, are components used to connect shafts to shafts, typically for pipe ends. They are also used at equipment inlets and outlets, such as on reducers. Flange connections or flange joints refer to removable joints made up of flanges, gaskets, and bolts that form a combined sealing structure. Pipe flanges are those used in piping installations, while those on equipment refer to the equipment's inlet and outlet flanges. Flanges have holes, and bolts secure them together. Gaskets are used to seal between flanges. Flanges come in threaded (screwed) connections, welding flanges, and clamp flanges. Flanges are always used in pairs; low-pressure pipelines can use threaded flanges, while those over four kilograms of pressure use welding flanges. Two flange discs are joined with a sealing gasket and then bolted together. Flanges of different pressures have varying thicknesses and require different bolts. When connecting equipment like pumps and valves to pipelines, these devices often have localized法兰-shaped connections, also known as flange joints. Any connection piece that uses bolts to join two flat surfaces around the circumference and is sealed is generally called a "flange," such as in ventilation pipe connections. These components can be referred to as "flange-type parts." However, such connections are only part of a device, like the connection between a flange and a pump, so it's not advisable to call the pump a "flange-type part." Smaller components like valves can be referred to as "flange-type parts."