Specification for the installation and use of metal gasket
In the pipeline pressure and temperature of medium little change conditions, such as industrial water supply and drainage pipeline, industrial gas pipeline can choose basic model of the flexible graphite spiral wound gasket, but when installation should pay attention to two points:
①The pre-tightening force must be moderate, not too small nor too much, can't appear visible bias phenomenon;
②The gasket shall not be deflected to ensure that the sealing medium does not directly flush the inner ring of the gasket.
Under the working condition that the pressure and temperature of pipeline conveying medium vary greatly, such as the pipeline of thermal system, for the convex and concave flange, the gasket flexible graphite metal winding with inner reinforcing ring should be selected.For flat flanges, flexible graphite metal winding pads with inner and outer reinforcing rings should be selected.
1.The inner diameter of the inner reinforcement ring is about 12mm larger than the size, and the outer diameter of the concave flange is 0.5~1mm straight to ensure that the sealing medium will not be strong ring.
2.When installing the inner and outer reinforcing ring metal winding pad, the inner diameter of the inner reinforcing ring should be 1~2mm larger than the diameter
And pay attention to the alignment, to ensure that the sealing medium will not flush the inner reinforcing ring
1.The winding part of the gasket must be between the flange sealing surface, and the width of the winding part cannot be widened at will, which is bound to affect the bolt compression force, thus affecting the sealing performance of the gasket
2.It is better not to use the basic gasket on the concave and convex surface flange, because the basic gasket in the flange axial compression force, gasket inner ring welding spot is easy to open, resulting in gasket failure.
3.Under the harsh working conditions such as high temperature, deep cold or frequent alternating heat and cold, large vibration and strong corrosive medium, the gaskets for plane flange and convex flange had better be equipped with inner rings of reasonable materials.
4.Never use low material gasket to replace high material artifact to avoid material corrosion, abrasion or other causes of gasket failure.
5.Before installation, carefully check the quality of flange, bolt, nut and gasket, carefully check the installation of flange or interface, there are unbiased opening, wrong opening, opening, wrong hole and other defects.
6.Flange or sealing surface must be cleaned, gasket surface and bolts, threads are not allowed to adhere to mechanical impurities.Gasket can not be installed out of alignment, should ensure uniform compression.
7.Apply uniform force to the nut. The bolt should be rotated symmetrically and evenly for 2 to 3 times to make the gasket pressure even.