What's the flange connection?

       Introduction

Before answer the question that what"s flange connection, I would like to ask you a question——what's flange? The flange is a kind of accessory that can be connected with bolts. Usually, it looks like this:

                                           

In addition, we connect it with a pipe, then connect two flanges so as to connect the two pipes. This kind of connection means flange connection.

 

The connection of flange and pipe has different types, but the connection between flanges is the same. According to the way flange connected with pipe, flange has thread, weld and loose three kinds.

1. Thread flange. This flange has the characteristics of convenient installation and maintenance. Besides, when we have to deal with the pipe which can not be easily welded, thread flange is also a good idea. But if the temperature of the material changes rapidly, or the temperature is too high(>=260℃)  or too low(<=-45℃), we can not use thread flange. 

2. Weld flange. This flange has flat welding, butt welding, and socket welding three types. A flat welding flange is suitable for low and medium-pressure pipelines. Butt welding is fine with medium and high-pressure pipelines. Socket welding flange is suitable for pressure from 1mpa to 10mpa.

3. Loose flange. The loose flange has strong corrosion resistance, but can't afford pressure.

 

How to connect two flanges?

1. The center of pipes should be the same as the center of flanges, and the pipes should be perpendicular to the connection surface of the flanges. What's more, the position of the round holes should correspond to the same.

2. It would be easy to exchange the tubes if use the same seals in the pipes that pressure are the same. And as for rubber slabs, the seals should also be made from rubber. 

3. The connection surface of the flanges should keep clean and smooth without burrs. The nut which is used to connect should be complete without any defects, and the fitting should be natural. Then the seals should be flexible and without damage or scratches. Before connecting the flanges, we should clean the flanges first.

4.The flange installation position on the branch pipe should be more than 100 mm from the outer wall of the riser, and the distance from the wall of the building should be 200 mm or more. And the nuts should be installed in the same direction. Whats' more, don't put the flange underground, or you should do anti-corrosion treatment.