Flange, also known as a flanged disk or rim. A flange is a component used to connect shafts together or to join pipe ends; it's also used at equipment inlets and outlets, such as a reducer flange. Flange connection or flange joint refers to a removable joint consisting of a flange, gasket, and bolts, forming a combined sealing structure. Pipe flanges are the flanges used in piping installations; on equipment, they refer to the equipment's inlet and outlet flanges. Flanges have holes, and bolts secure them tightly together. They are sealed with a gasket. Flanges are available in threaded (screwed) connections, welding connections, and clamp connections. Flanges are always used in pairs; low-pressure piping can use threaded flanges, while above four kilograms of pressure requires welding flanges. Two flange disks are joined with a sealing pad and then bolted together. Flange thickness and bolt types vary depending on the pressure. Pumps and valves, when connected to pipes, have corresponding flange shapes for these equipment parts, also known as flange joints. Any connection piece that uses bolts to join two flat surfaces around the perimeter and seal them is generally called a "flange," such as in ventilation pipe connections, these parts can be referred to as "flange-type components." However, this type of connection is only a part of a device, such as the connection between a flange and a pump, so it's not appropriate to call the pump a "flange-type component." Smaller items like valves can be called "flange-type components."