NEWS CENTER

Flange connection is to fix two pipes, pipe fittings or equipment on a flange plate, between the two flanges, and add flange pads (on-site flange repair) to fasten together with bolts to complete the connection. Some pipe fittings and equipment have their own flanges, which are also flange connections. Flange connection is an important connection mode in pipeline construction. The flange connection is easy to use and can withstand greater pressure. In industrial pipelines, in the home, the pipe diameter is small, and it is low pressure, and the flange connection is not visible. If in a boiler room or production site, there are flanged pipes and equipment everywhere.

Flange bolt fastening method-pressure vessel flange sealing surface repair manufacturers to explain for everyone

1. No torque ring wrench or hammer wrench: suitable for general equipment and pipeline flange fastening, according to the bolt size and flange pressure level.
The fastening requirements are as follows:

1) Position the gasket with 4 bolts at positions 1 , 2 , 3 and 4 to ensure that the center of the wound gasket is within the flange edge.

2) Tighten the positioning bolt by hand, then insert other stud bolts and balance the load by hand, ensuring that at least 2 threads are exposed at each end of the nut.

3) According to the field equipment and flange, the fastening times and the hammering load of each fastening shall be reasonably determined according to the calculation of one fastening circle. The fastening hammering load shall be fastened from small to large in sequence. The unloadable load shall be too fast and too large to prevent the gasket seal from failing.

4) Each tightening sequence of torque-free ring wrench or hammer wrench: tighten two diametrically opposite bolts to the established hammering load of the bolts; tighten another pair of bolts about 90 degrees away from the previous two bolts along the circumference; continue to tighten until all other bolts are tightened to the established hammering load.

5) Finally, tighten all bolts clockwise or counterclockwise according to 100% hammer load.

2. Torque wrench: suitable for high temperature and high pressure, flammable and explosive and other important equipment and pipeline flange.
The fastening requirements are as follows:

1) The maintenance unit shall formulate a fastening scheme and appropriate torque, and carry out design review according to the bolt strength, the initial sealing specific pressure of the gasket (flange repair in chemical plant), the working sealing specific pressure, the medium pressure and other parameters to prevent the bolt from breaking and the gasket from losing elasticity due to excessive pressing force, resulting in seal failure.

2) Position the gasket with 4 bolts at positions 1 , 2 , 3 and 4 to ensure that the center of the wound gasket is within the flange edge.

3) Tighten the positioning bolt by hand, then insert other stud bolts and tighten them by hand to balance the load, ensuring that at least 2 threads are exposed at each end of the nut.

4) According to the field equipment and flange, the fastening times and each fastening torque shall be reasonably determined according to the calculation of one fastening circle. The fastening torque shall be tightened from small to large, and the non-loadable load shall be too fast and too large to prevent gasket sealing failure.

5) The sequence of each tightening of the torque wrench: tighten two diametrically opposite bolts to the predetermined torque of the bolt; tighten another pair of bolts about 90 degrees apart from the previous two bolts along the circumference; continue to tighten until all other bolts are tightened to the predetermined torque.

6) Finally, tighten all bolts clockwise or counterclockwise according to the torque value of 100% (on-site flange processing).

7) Record the torque value for reference in future maintenance.

3 Bolt Tensioner:
Applicable to high temperature and high pressure, flammable and explosive and other important equipment and pipeline flange. The fastening requirements are as follows:

1) The maintenance unit shall formulate the fastening scheme, formulate the appropriate tensile force, and carry out design review according to the bolt strength, the initial sealing specific pressure of the gasket, the working sealing specific pressure, the medium pressure and other parameters to prevent the bolt from breaking and the gasket from losing elasticity due to excessive pressing force, resulting in seal failure.

2) When a bolt tensioner is used to tighten a single bolt, it shall be tightened according to the principle of uniformity of bolt tightening and refer to the tightening sequence of torque wrench.

3) During the stretching and fastening process of the bolt tensioner, the number of stretching and fastening times shall be reasonably determined. The pressurization shall be carried out in turn from small to large, and uniform pressurization shall be carried out. For each increase of a certain pressure, the pressure shall be stabilized and then increased to avoid excessive impact tension and affect the pre-tightening effect of the bolt.