How many types of flange connection methods are there?

How many types of flange connection methods are there?

Currently, many people do not know what flanges are. Flanges are actually quite common in pipelines. So, how many flange connection methods are there?

How many types of flange connection methods are there?

1. Flat welding: only weld the outer layer, not the inner layer; There are three types of sealing surfaces commonly used for welding flanges in medium and low pressure pipelines with nominal pressures below 0.25 MPa, namely smooth surface, concave convex surface, and tongue and groove surface. Among them, smooth surface is widely used, affordable, and cost-effective.

2. Butt welding: Both the inner and outer layers of the flange need to be welded, usually used for medium and high pressure pipelines. The nominal pressure of the pipeline is between 0.25 and 2.5 megapascals. The sealing surface of the welded flange connection is uneven, the installation is complex, and the labor cost, installation method, and auxiliary material cost are relatively high.

3. Socket welding: generally used for pipelines with nominal pressure less than or equal to 10.0MPa and nominal diameter less than or equal to 40mm.

4. Loose sleeve: Generally used on pipelines with low pressure but corrosive media, this flange has strong corrosion resistance and is mainly made of stainless steel.

This type of connection is mainly used for connecting cast iron pipes, lined rubber pipes, non-ferrous metal pipelines, flange valves, etc. Flange connection is also used for the connection between process equipment and flanges.

What is the process of flange connection?

Firstly, the connection between the flange and the pipeline should meet the following requirements:

The center of the pipeline and flange should be on the same horizontal plane.

2. The center of the pipeline is perpendicular to the flange sealing surface at a 90 degree angle.

3. The position of flange bolts on the pipeline should be consistent.

What are the requirements for flange gaskets?

1. The flange gaskets for the same pipe and pressure should be the same and can be exchanged with each other in the future.

2. For pipes with rubber sheets, choose rubber gaskets, such as water pipes.

The principle of gasket selection is to choose gaskets with a smaller width as much as possible, and follow the premise that the gasket will not be crushed.

What is the flange connection flange like?

1. Check if the specifications of flanges, bolts, and gaskets meet the requirements.

2. The sealing surface should be kept smooth, clean, and free of burrs.

3. The thread of the bolt should be intact and naturally embedded.

4. The material of the gasket should be flexible, not easily aged, and the surface should be free of defects such as damage, wrinkles, scratches, etc.

5. Before assembling the flange, clean the flange, remove oil stains, dust, rust, and other debris, and remove the sealing line.

How to assemble flanges?

1. The flange sealing surface is perpendicular to the center of the pipeline.

2. The installation direction of bolts with the same specifications is the same.

3. The flange installation position on the branch pipe should be at least 100mm away from the outer wall of the riser and 200mm away from the building wall.

4. Do not bury the flange directly underground as it is prone to corrosion. If buried underground, anti-corrosion treatment should be carried out.