Adaptor Flange

Flange connection is the two pipes, pipe fittings or equipment, first fixed on a flange, and then between the two flanges with flange pad, and finally with bolts to pull the two flanges tightly together a detachable joint. Connections can be made between stationary pipes and rotating or reciprocating equipment.

Flange connection can be generally divided into five kinds: flat welding, butt welding, socket welding, loose sleeve, thread.

Here are the four kinds of detailed elaboration:

1. Flat welding: only welding the outer layer, do not need to weld the inner layer; Generally used in medium and low pressure pipelines, the nominal pressure of the pipeline is less than 0.25mpa. There are three kinds of sealing surface of flat welding flange, namely smooth type, concave and convex type and tenon groove type, among which smooth type is the most widely used, and affordable, cost-effective.

2. Butt welding: the inner and outer layers of the flange should be welded. It is generally used for medium and high pressure pipelines, and the nominal pressure of the pipeline is between 0.25 and 2.5MPa. The sealing surface of butt welding flange connection is concave-convex, installation is more complex, so the labor cost, installation method and auxiliary material cost are relatively high.

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

4. Loose sleeve: generally used for the pressure is not high but the medium is more corrosive in the pipeline, so this kind of flange has strong corrosion resistance, the material is mainly stainless steel.

This kind of connection is mainly used for the connection of cast iron pipe, rubber lining pipe, non-iron metal pipe and flange valve, etc., the connection of process equipment and flange is also used flange connection.

Flange connection process is as follows:

First, the connection of flange and pipeline should meet the following requirements:

1. The center of the pipe and flange should be on the same level.

2. The sealing surface of the pipe center and flange is 90 degrees vertical.

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

Second, gasket flange gasket, the requirements are as follows:

1. in the same pipe, the flange with the same pressure should choose the same gasket, so as to facilitate mutual exchange in the future.

2. for the use of rubber sheet pipe, gasket is also the best choice of rubber, such as water pipeline.

3. the selection principle of gasket is: as close as possible to small width selection, this is to determine the premise of gasket will not be crushed should follow the principle.

Third, connect the flange

1. check whether flange, bolt and gasket specifications meet the requirements.

2. the sealing surface should be kept smooth and neat, without burrs.

3. bolt thread to complete, can not have defects, chimerism to natural.

4. gasket texture should be flexible, not easy to aging, no damage, wrinkles, scratches and other defects on the surface.

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

Fourth, assembly flange

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

2. Bolts of the same specifications shall be installed in the same direction.

3. The flange installation position on the branch pipe should be more than 100 mm away from the outer wall of the riser, and the distance from the wall of the building should be more than 200 mm.

4. do not bury the flange directly in the ground, easy to be corroded, if you must be buried in the ground, it is necessary to do a good job of anti-corrosion treatment.

Flange connection is an important connection mode in pipeline construction.

Flange types, according to the flange and pipe fixed way into thread flange, welding flange, loose flange; According to the sealing surface form, can be divided into smooth type, concave and convex type, tenon groove type, lens type and trapezoidal groove type.

General low pressure small diameter with wire flange, high pressure and low pressure large diameter with welding flange, flange thickness and connecting bolt diameter and number of different pressure is different.

According to the different pressure levels, flange gaskets are also made of different materials, from low pressure asbestos gaskets, high pressure asbestos gaskets and tetrafluoron gaskets to metal gaskets.

Flange connection is easy to use and can withstand large pressure.

In the industrial pipeline, flange connection is widely used, such as in the indoor fire hydrant water supply system, butterfly valve, gate valve, check valve and other types of valve and pipeline connection.

The main characteristics of flange connection are easy to disassemble, high strength and good sealing performance. When installing flanges, the two flanges should be parallel. The sealing surface of the flanges should not be damaged and should be cleaned up. Flange gaskets should be selected according to design requirements.