Flange, also known as a flange collar or rim. A flange is a component that connects two shafts, used for joining pipe ends; there are also flanges used at equipment inlets and outlets for connecting two pieces of equipment, such as a reducer flange. Flange connection or flange joint refers to the removable connection formed by the combination of flange, gasket, and bolt. Pipe flanges are flanges used in piping systems within equipment, referring to the inlets and outlets of the equipment. Flanges have holes, and bolts secure the two flanges together. Gaskets are used to seal between the flanges. Flanges come in threaded (screwed) connections,焊接 (welded) flanges, and clamp flanges. Flanges are used in pairs; low-pressure pipelines can use threaded flanges, while pipelines over four kilograms of pressure require焊接 flanges. A sealant pad is placed between two flange disks, then secured with bolts. Flange thickness and bolt types vary depending on pressure ratings. Equipment like pumps and valves, when connected to pipes, have corresponding flange shapes, also known as flange joints. Any connection component that uses bolts to join two flat surfaces and seal them is generally called a "flange," such as the connection of ventilation pipes. These components can be referred to as "flange-type parts." However, such connections are only a part of a single piece of equipment, 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."