Flange, also known as a flange hub or rim. A flange is a component that connects shafts to each other and is used for connecting pipe ends; there are also flanges used at equipment inlets and outlets for connecting two pieces of equipment, such as reducer flanges. Flange connection or flange joint refers to a removable joint made up of the flange, gasket, and bolts working together as a combination sealing structure. Pipe flanges refer to flanges used in piping installations, and when used on equipment, they refer to the equipment's inlet and outlet flanges. Flanges have holes, and bolts secure the two flanges together. Flanges are sealed with gaskets. Flanges are divided into threaded (screwed) flanges,焊接 flanges, and clamp flanges. Flanges are always used in pairs; low-pressure pipelines can use threaded flanges, while pipelines over four kilograms of pressure use焊接 flanges. Two flange discs are fitted with a sealing gasket and then secured with bolts. Flanges of different pressure ratings have varying thicknesses, and different bolts are used for them. When pumps and valves are connected to pipes, the local parts of these equipment pieces are also made into corresponding flange shapes, also known as flange joints. Any connection piece that uses bolts to connect two flat surfaces and seal them is generally called a "flange," such as the connection of ventilation pipes. These types of components can be called "flange-type parts." However, such a connection is just 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 items like valves can be called "flange-type parts."