Flange assembly, gasket materials and fasteners
Flange assembly
1. Before assembling the flange, the flange surface, especially the sealing surface, must be cleaned.
2. When assembling slip-on flange, the pipe end should be inserted into two third of the inner diameter of the flange, and then the flange and the pipe are spot welded in one place. If it is a horizontal pipe, it should be spot welded from above, and then use an angle square to check and calibrate the position of the flange from different directions, so that the sealing surface is perpendicular to the centerline of the pipe. If there is no mistake, weld the second spot.
3. Correct the position of the flange from the left and right directions with an angle square. After correcting, weld the third and fourth spots, and the spot welding process is completed.
4. For companion flanges, the bolt holes of the flanges to be mounted should be aligned and parallel with the corresponding bolt holes of the already fixed flanges. The deviation should not be greater than 1.5‰ of the outer diameter of the flange, and no more than 2mm.
5. When selecting the flanges for the equipment or valve parts, it should be noted that the size of the flanges for the original equipment or valve parts are the same as that of the flanges used for the pipes.
Common rubber gasket materials
Rubber sheets and rubber asbestos sheets are the most commonly used flanged gasket materials.
1. Industrial rubber sheet - It is also called an industrial vulcanized rubber sheet or a rubber sheet.
2. Rubber asbestos sheet - It is generally used as a gasket for equipment and pipe flange connection sealing surface. The medium can be water, steam, air, various gas, ammonia, lye, and oil.
Flange fasteners
Flange fasteners refer to bolts, nuts, and washers used to connect flanges. Hex head bolts are usually used for low pressure pipes while stud bolts are used for medium and high pressure pipes. The nuts that are matched with the bolts are divided into two types - The first type nuts are rounded on one side of the hexagon, the other side is flat. And the second type is rounded on both sides. The hardness of the nut should be less than that of the bolt or stud so as to avoid the nut breaking the thread on the bolt, and reduce the fastness after a long period of time.
For better disassembly and repair, the protruding length of the nut should be within 5 mm after the flange is tightened, and not more than twice the pitch. Washers do not have to be added if there are flange connecting bolts. When the thread on the screw is slightly shorter, a washer can be added as the length compensation to leave room for the subsequent secondary tightening. But it is strictly forbidden to use the superimposed washer to compensate for the shortage of the thread length. The number and diameter of bolt holes on the flange and the specifications of the connecting bolts are specified in the relevant flange standards. The flange bolt holes are generally 2 to 3 mm larger than the bolt or stud diameter.
1. Before assembling the flange, the flange surface, especially the sealing surface, must be cleaned.
2. When assembling slip-on flange, the pipe end should be inserted into two third of the inner diameter of the flange, and then the flange and the pipe are spot welded in one place. If it is a horizontal pipe, it should be spot welded from above, and then use an angle square to check and calibrate the position of the flange from different directions, so that the sealing surface is perpendicular to the centerline of the pipe. If there is no mistake, weld the second spot.
3. Correct the position of the flange from the left and right directions with an angle square. After correcting, weld the third and fourth spots, and the spot welding process is completed.
4. For companion flanges, the bolt holes of the flanges to be mounted should be aligned and parallel with the corresponding bolt holes of the already fixed flanges. The deviation should not be greater than 1.5‰ of the outer diameter of the flange, and no more than 2mm.
5. When selecting the flanges for the equipment or valve parts, it should be noted that the size of the flanges for the original equipment or valve parts are the same as that of the flanges used for the pipes.
Common rubber gasket materials
Rubber sheets and rubber asbestos sheets are the most commonly used flanged gasket materials.
1. Industrial rubber sheet - It is also called an industrial vulcanized rubber sheet or a rubber sheet.
2. Rubber asbestos sheet - It is generally used as a gasket for equipment and pipe flange connection sealing surface. The medium can be water, steam, air, various gas, ammonia, lye, and oil.
Flange fasteners
Flange fasteners refer to bolts, nuts, and washers used to connect flanges. Hex head bolts are usually used for low pressure pipes while stud bolts are used for medium and high pressure pipes. The nuts that are matched with the bolts are divided into two types - The first type nuts are rounded on one side of the hexagon, the other side is flat. And the second type is rounded on both sides. The hardness of the nut should be less than that of the bolt or stud so as to avoid the nut breaking the thread on the bolt, and reduce the fastness after a long period of time.
For better disassembly and repair, the protruding length of the nut should be within 5 mm after the flange is tightened, and not more than twice the pitch. Washers do not have to be added if there are flange connecting bolts. When the thread on the screw is slightly shorter, a washer can be added as the length compensation to leave room for the subsequent secondary tightening. But it is strictly forbidden to use the superimposed washer to compensate for the shortage of the thread length. The number and diameter of bolt holes on the flange and the specifications of the connecting bolts are specified in the relevant flange standards. The flange bolt holes are generally 2 to 3 mm larger than the bolt or stud diameter.