- Shaft seal system warming. (a) The shaft seal should be warmed up before supplying steam to the steam feed line so that the hydrophobic drainage is exhausted;
- Coiling in operation. Steam shall be fed to the shaft seal in continuous coiling condition. Hot start should be preceded by sending steam to the shaft seal for supply and followed by evacuation;
- choose the proper time to feed steam. If the steam is supplied to the shaft seal too early before the start, the temperature difference between the upper and lower cylinders will increase or the expansion difference will increase; if it is too late, it will delay the time for vacuum to be established (or increased);
- temperature matching. Pay attention to matching the temperature of the shaft seal vapour to the temperature of the metal. It is best to use a high temperature steam source with the appropriate temperature for hot start, which is conducive to the control of the expansion difference, while it is best to use a low temperature steam source for cold start;
- be careful when switching steam sources. In the high and low temperature shaft seal steam source switch must be careful, switch too quickly not only cause significant changes in expansion difference, and may produce uneven thermal deformation at the shaft seal, resulting in friction, vibration, etc..
