Mechanical seal for kettle Maintenance methods

The service life of the mechanical seal for kettle varies with the conditions and environment, and is closely related to the working temperature, working pressure, materials in the kettle, rotating speed, sealing liquid medium, deviation, vibration and movement of the mixing shaft. Therefore, careful operation and maintenance are very important to improve the service life of mechanical seals.

1. It should be noted that when starting the stirring equipment for the kettle, the pressure of the circulating protection system must be slowly increased first, and then the pressure in the kettle can be slowly increased. The pressure of the circulating protection system should always be 0.05~0.10MPa higher than the pressure in the kettle (at least not lower than the pressure in the kettle).

2. When stopping the machine, stop the mixing drive system first, and then close the circulating system and cooling water after the temperature and pressure in the kettle are reduced to normal temperature and pressure.

3. During the mechanical seal operation, pay attention to maintaining the liquid level specified in the lubrication tank or circulating system. Any position lower than the specified position shall be supplemented to prevent dry grinding (except for 202F type), and the seal leakage outlet shall be kept unblocked.

4. When driving, if there is slight leakage at the seal, you can wait for a period of time to make it automatically run and adjust, and gradually reduce with the extension of the running time, indicating that it can be eliminated with continuous operation.

5. In case of sudden and continuous leakage, it usually indicates that the auxiliary seal ring is damaged or foreign matters enter the sealing surface. If the sealing surface is damaged, it should be treated.

6. If whistling is found, it means that the sealing surface is in the state of insufficient liquid supply and dry grinding occurs, and the sealing fluid flow of the circulating system should be checked immediately, but not all dry grinding will have whistling.

7. The inlet and outlet temperature of sealing fluid shall meet the requirements of Article 3 of the selection principle of isolating fluid (sealing fluid); The cooling water outlet shall meet the requirements of point 3 of Article 2 for cooling and lubrication of mechanical seal for kettle.

8. When the leakage exceeds the allowable value, check and analyze the cause of leakage:

1) Whether the sealing fluid contains scale, rust and other solid impurities;

2) Whether the axial movement and radial swing of the shaft exceed the specified value;

3) Whether the speed, temperature, pressure and other conditions exceed the standard;

4) Whether the circulating system works normally and whether the pressure meets the requirements;

5) Whether the cooling water is unblocked and plays a cooling role;

6) The leaked liquid is turbid and black, indicating that the graphite ring is severely worn.

9. In general, the mechanical seal for kettle should not be dismantled easily. Except when absolutely necessary, it can be dismantled for inspection and maintenance, but it should be carried out by maintenance personnel with certain technical skills.

10. The disassembly and assembly of various types of mechanical seals shall be carried out according to the structural drawings, as follows:

1) The disassembled parts shall be cleaned and inspected;

2) Check the wear of moving ring and stationary ring. The general height of the stationary ring (soft ring) step is 3mm, and new parts must be replaced when the wear is less than 1mm;

3) The rotating and stationary rings can still be used after inspection, but the sealing face must be reground. The flatness after grinding shall reach 0.0009mm, the roughness Ra of hard ring shall be ≤ 0.2mm, and that of soft ring shall be ≤ 0.2mm

4) For all auxiliary sealing rings (including oil seals), all aged, expanded, damaged and worn bearings shall be replaced with new ones;

5) The mechanical seal after repair and assembly shall be installed according to the installation procedures and key points of various types of mechanical seals in this manual.