What is loose flange or lap joint flange?

Flanges can be divided into five basic types according to their connection with pipes:flat welded flange,butt welded flange,threaded flange,socket welded flange and loose flange.There are many types of flange sealing surface,such as protruding surface (RF),concave surface (FM),convex surface (M),tenon surface (T),groove surface (G), full plane (FF) and ring connection surface (RJ).

Slip on ring lap joint flange

Among them,the loose flange is actually equivalent to the combination of two flanges,as shown in the below figure:

Commonly used as a connection is a change of material.

Loose flange is to use flanges,steel rings to cover the flange on the end of the pipe,the flange can move on the end of the pipe.Steel rings or flanges are sealing surfaces, and flanges are used to compress them.It can be seen that the loose sleeve flange is not in contact with the medium because it is blocked by the steel ring or flanging.

Loose flange is suitable for the connection of non-ferrous metals such as steel,aluminium and stainless acid-resistant steel containers and corrosion-resistant pipelines.

Loose flange is movable flange,which is usually matched with water supply and drainage fittings (expansion joint is the most common).When the manufacturer leaves the factory,there is one flange at both ends of expansion joint,which is directly connected with the bolts of pipelines and equipment in the project.

It’s the kind of flange with loopers.Usually used in pipes,in that case,loosening bolts can rotate the pipes on both sides,and then tighten.It is convenient to disassemble and assemble pipelines.Loose flange is also called lap joint flange.

Haihao Group can manufacture all types flange products,which according to standard:ANSI/ASME B16.5,B16.36,B16.47,B16.48,AWWA C207,BS 10,BS 4504,DIN,EN 1092-1,JIS,GOST,SANS 1123,UNI etc.If you want to know more about our products,please email us:sales@haihaogroup.com