1. How to connect flanges and pipes?

The installation of flanges and pipelines not only affects the strength and tightness of the connection but also affects the eccentricity of the entire pipeline. Therefore, to assemble flanges on the pipeline, the following basic requirements must be met:

(1) The centers of the flange and the pipe are on the same line

(2) The flange sealing surface should be perpendicular to the center of the pipe

(3) The position of the screw holes of the flanges at both ends of the  pipe should be the same, and coincide with the positions of the screw holes on the matched equipment or fittings

2. Installation of flat welding flange and pipe

When assembling the flange and the pipe, first sleeve the flange into the pipe end, leaving a certain distance between the pipe mouth and the flange sealing surface (usually 1.5 times the pipe wall thickness). Spot welding can be performed on either side of the pipe. Use a flange curve ruler or square to correct the opposite side of the spot welding, and look for the right spot welding. Rotate the pipe by 90° to make the spot welding point located at the top and bottom, and then use a curved ruler to align the left and right sides of the pipe end, and then spot welding can be done on the left and right sides.

The flange connection should be kept coaxial, and the deviation of the bolt hole center is generally not more than 5% of the hole diameter to ensure the penetration of the bolt.Flange connection should use bolts of the same specification, and the installation direction is the same (nuts are on the same side).