The Principle and Application of Threaded Flanges

Threaded flanges are suitable for low and medium pressure pipelines, commonly used in industrial and civil pipelines such as fire protection, gas, hot and cold water, air pressure, and hydraulic pipelines, especially in situations where welding is not allowed. The usage method is to thread the inner hole of the flange and the pipe of the pipeline, and then connect them by rotating and tightening without welding.

Threaded flanges do not belong to high-pressure flanges, and their applicable pressure range is generally between 0.6~4.0Mpa, with a diameter of DN10~DN150. Despite the relatively high cost of threaded flanges, they are still a popular connection method in many situations due to their ease of installation and maintenance.

The connection principle of threaded flanges is relatively simple, mainly relying on the matching connection between the flange inner hole and the threads made by the pipes on the pipeline. Specifically, it means threading the flange inner hole, then threading the corresponding thread on the pipeline, and finally connecting the two by rotating and tightening. This connection method does not require welding, so it will not cause welding stress and deformation to the pipeline, and the additional torque generated to the cylinder or pipeline is also very small.

However, it should be noted that under conditions of rapid temperature changes in the pipeline or temperatures above 260 ℃ and below -45 ℃, threaded flanges may leak due to thermal expansion and contraction or changes in material properties. Therefore, under these conditions, it is recommended not to use threaded flanges.

Instructions for use

Thread processing: Process pipe threads at the end of the pipeline that needs to be connected, matching the internal hole threads of the threaded flange.

Connecting pipeline: Screw the processed pipeline into the flange.

Tightening connection: The flange is tightly connected to the pipe by rotating and tightening.

Sealing: The threaded connection between flanges and pipelines can achieve preliminary sealing, but in high-pressure or strict requirements, it may be necessary to use sealing gaskets and bolts in conjunction to achieve reliable sealing.