What Is the Lap Joint Flange with Welding Neck Collar?

Lap joint flanges can be mainly divided into four types: loose plate steel pipe flanges with weld-on collar, loose plate steel pipe flanges with welding neck collar, lap joint flanges with welding neck collar and lap joint flanges with welding neck collar.
 
The roles of lap joint flanges
Lap joint flanges mainly play the roles of connecting equipment or flanges such as the flanges on the water pumps or the valves. Lap joint flanges have the following two obvious features.
 
1. Lap joint flanges are easy to be installed. For example, if the equipment has not arrived at the construction site, but the pipelines have already been arranged, the lap joint flanges can be used under this condition. When the equipment arrives, it is simple to install the lap joint flanges on the equipment because the lap joint flanges are flexible and movable, and the problem that the bolt can not fit the blot hole will never happen.
 
2. It is convenient to change the material of the pipelines if the lap joint flanges are adopted, for example, changing the stainless steel pipes to the carbon steel pipes. When the stainless steel pipes have to be changed to the carbon steel pipes in engineering, in order to save the costs for the construction, the flanges can be made of stainless steel while the welding necks can be made of carbon steel, which will form a perfect transformation. Actually, such a case usually happens in engineering for the purpose of saving materials and money.
 
Loose plate flanges with welding neck collar
Loose plate flanges with welding neck collar consist of the slip-on flanges and the butt welding nozzles. The appearance of the butt welding nozzle almost the same as the welding neck flange's, but the outer diameter of the butt welding nozzle is smaller than that of the welding neck flange. The butt welding nozzle does not have the bolt hole so as to make itself easily welded to the pipes and make the slip-on flanges flexible and movable. The slip-on flanges can always be connected with the pipes no matter what conditions the bolt hole are under.
 
The manufacturing standard of loose plate flanges with welding neck collar:
1. GB/T9120-2010
2. JB/T84-2015
3. ISO 7005-1-2011
4. BS 4504-3.1
5. DIN EN 1092-1-2008