Flange (Flange) is also called flange or flange flange. Flange is a part that makes the tube and pipe interconnected, connected at the end of the tube. The flange has an eyelet, and the bolt makes two flanges tightly connected. The flange is sealed with a gasket. Flanges are divided into threaded connection (wire connection) flange and welding flange.

A. What is a flange Flange (Flange) is also called flange or flange edge. Flange is to make the tube and pipe interconnected parts, connected at the end of the pipe. Flange with eyelets, bolts so that the two flanges tightly connected. The flange is sealed with a gasket. Flanges are divided into threaded connection (wire connection) flange and welding flange. 　　Flange is a disk-shaped parts, the most common in pipeline engineering, flange are used in pairs. In pipeline engineering, flanges are mainly used for the connection of pipes. In the need to connect the pipeline, a variety of installation of a piece of flange, low-pressure pipeline can use the fillet flange, 4 kg pressure above the use of welding flange. Seal points are added between the two flanges and then fastened with bolts. Different pressure flanges have different thickness and use different bolts. 　　Pumps and valves in the connection with the pipeline, these equipment and equipment local, but also made corresponding flange shape, also known as flange connection. Where the two planes in the periphery of the use of bolts while closed connection parts, generally known as "flange", such as the connection of ventilation ducts, this type of parts can be called "flange parts". But this connection is only a partial equipment, such as flange and pump connection, it is not good to call the pump "flange class parts". Smaller ones, such as valves, can be called "flange parts".  -(3) mechanical industry flange standard JB/T74~86.2-1994; (See: Ministry of Machinery flange standard) (4) petrochemical industry flange standard SH3406-1996. Now take the national standard as an example to illustrate the selection of flange. The national standard flange is divided into two major systems: the European system and the American system. The nominal pressure of the European system flanges are: PN0.25, PN0.6, PN1.0, PN1.6, PN2.5, PN4.0, PN6.3, PN10.0 and PN16.0MPa; the nominal pressure of the American system flanges are: PN2.0, PN5.0, PN11.0, PN15.0, PN26.0 and PN42.0MPa 2. The basis for selecting the flange (1) the nature of the transport medium, general media, special media, toxic media, flammable and explosive media; (2) according to the parameters of the medium, working pressure, working temperature, in the case of the medium is determined, according to the working temperature and working pressure of the medium to determine the nominal pressure of the flange PN. (3) according to the place of use, connection conditions to determine the flange and the pipe connection and sealing surface form. (4) according to the connection object to determine the flange specifications.