Contact person: Manager Hu
Mobile phone: 13306731296
Seat plane: 0573-86055560
Address: Xu Youche Village, Guantang, Haiyan County, Jiaxing City, Zhejiang Province
(1) Flange connections shall be maintained on the same axis, and the center deviation of bolt holes shall generally not exceed 5% of the hole diameter, and bolts shall be guaranteed to penetrate freely. The connecting bolts of flanges should be of the same specification, the installation direction should be the same, and the bolts should be tightened symmetrically and evenly.
(2) Inclined gaskets of varying thickness shall not be used to compensate for the non-parallelism of flanges. Double washers shall not be used. When large caliber gaskets need to be spliced, they should not be butted with flat caliber, but with oblique lap or labyrinth.
(3) In order to facilitate the installation and removal of flanges and fasten bolts, the distance between the flange plane and the support and the wall should not be less than 200 mm.
(4) When tightening the bolt, it should be carried out symmetrically and crosswise in order to ensure that the gasket bears uniform force.
(5) Bolts and nuts shall be coated with molybdenum disulfide, graphite oil or graphite powder to facilitate future disassembly if:
(6) Stainless steel, alloy steel bolts and nuts; Pipeline design temperature is higher than 100 C or lower than 0 C; Open-air device; Atmospheric corrosion or corrosive medium.
(7) The metal gaskets such as copper, aluminium and mild steel should be annealed before installation.
(8) Flange bolts for high-temperature or low-temperature pipelines shall be hot or cold-tightened in accordance with the following provisions during trial operation;
(9) Hot-tightening or cold-tightening should be carried out after 24 hours of keeping working temperature; 2) When fastening pipe bolts, the maximum internal pressure of the pipe should be determined according to the design pressure. When the design pressure is less than 6 MPa, the maximum internal pressure of hot-tightening is 0.3 MPa; when the design pressure is greater than 6 MPa, the maximum internal pressure of hot-tightening is 0.5 MPa. Cold tightening should generally be carried out under pressure relief. Hot and cold tightening should be moderate, and safety measures should be taken.
(10) Flange connections are not allowed to be buried directly. Inspection wells should be installed at the flange joints of buried pipelines. If buried, anti-corrosion measures should be taken