1, the flange of the piping and piping center line of the verticality and flange bolt hole error should be in the range of allowable values. The valve and piping centerline are to be made consistent after the installation.

2, in fastening bolts, to use the matching nut with the wrench, when the use of oil pressure, pneumatic tools for fastening, pay attention to not exceeding the specified torque.

3, the connection of two flange, the first to make the flange sealing surface and gasket uniform pressure, thereby ensuring the same bolt stress on the flange connection.

4, flange fastening to avoid the uneven force, should be in accordance with symmetrical, the direction of the meaning of the order of rotation tight.

5, after the installation of the flange, to ensure that all the bolts and nuts are evenly fastened.

6, bolt and nut fastening, in order to prevent vibration caused by loosening, to use washers. In order to avoid high temperature adhesion between the thread, the installation of thread parts should be coated with anti-adhesion agent.

7, for more than 300 ℃ high temperature valve, in the temperature rise, the flange connecting bolts, bonnet fastening bolts, pressure seals and packing gland bolts again tightened.

8, Low-temperature valve when installed in the atmosphere at the temperature of the state, due to the formation of temperature difference, flanges, gaskets, bolts and nuts and other shrinkage, and because of the different materials of these parts

9, the respective linear expansion coefficient is also different, forming a very easy to leak environmental conditions. From this objective situation, when fastening bolts at ambient temperature, it is necessary to adopt the torque of the shrinkage factor of each component when the temperature is low.