Analysis of flange knowledge points

Analysis of flange knowledge points

Flange has a wide range of applications. It is not only a common part of the industrial field, but also plays an important role in the construction, light industry, heavy industry, plumbing, electric power and other industries. This paper analyzes the related concepts and knowledge points of flange in detail to help you understand and understand the flange in more detail.

1、 Classification of flanges

If the flange is classified according to the industry standard, there are generally four kinds: chemical industry standard, petrochemical industry standard, machinery industry standard and national standard. As the first three categories are highly professional, they are used to the national standard (GB) as the general standard in the market. According to the national standards, there are eleven types: integral flange, threaded flange, plate type flat welding flange, butt welding flange, neck flat welding flange, socket welding flange with neck, neck loose sleeve flange with butt welding ring and plate loose sleeve with butt welding ring

Flange, slip on ring plate loose flange, flanged ring plate loose sleeve flange, and flange cover.

2、 Concept of nominal pressure and nominal diameter of flange

The flange with different pressure has different thickness and matching bolts. In order to facilitate communication and understanding, two concepts of nominal pressure and nominal diameter are proposed.

1. Nominal pressure (PN): it is the standardized pressure level of pressure vessels or pipelines, which generally refers to the working pressure under the specified temperature, and the pressure level after standardization. The nominal pressure of flange is usually similar to the design pressure and slightly higher. There are two systems for international nominal pressure rating: European system (represented by DIN standard) and American system (represented by asmeb16.5 and b16.47). In the same system, the standards of pipe flange in different countries can basically match each other (referring to the size of connection and sealing surface), but the flange between the two systems can not be matched with each other.

2. Nominal diameter (DN): it is the size series after pipe standardization to facilitate the mutual matching of fittings, which is stipulated by national standards. The nominal diameter of pipe flange refers to the nominal diameter, which is a value close to the inner diameter of the pipe. The outer diameter of steel pipe with the same nominal diameter is the same, but the thickness is variable, so the inner diameter is also variable. For example, there are p108 × 4, p108 × 4.5, p108 × 5 and so on.

3、 Concept and function of flange

Flange, which is called the flange plate or flange by a few people, refers to the connecting parts that are connected by bolts in the periphery of two planes, that is, the parts connecting shafts with each other. It is also an important connection mode of pipeline construction. Because of the need to be closely connected with the device, the flange has holes, which can make the bolt tighten the flange. It is not only convenient for dry installation, but also for dry pulling and unloading. It is an indispensable part in the construction, light and light T industry, water heating, free force and other industries