Spray granulation drying equipment is PTC thermistor ceramics production process of important equipment, the higher equipment prices, the composition of complex, difficult to use and maintain. The good operation of the drying equipment not only ensures the normal production of PTC thermal ceramics, but also prolongs the service life of the equipment and reduces the production cost. Therefore, it is necessary to properly operate the equipment and strengthen the maintenance.
In the daily production process, the necessary preparations should be carried out before starting the drying equipment. First check whether the joints of the bearing and sealing parts of each device are loose, the condition of the lubricating oil of each mechanical component, and whether the water, wind, and slurry valve ports are in the desired positions. Then turn on the power to check whether the voltage and the meter are normal. Finally, check the amount and concentration of the slurry in the slurry mixing tank. If there is any problem, it should be eliminated in time.
Then, the blower and the exhaust fan are sequentially turned on, and then the heating switch is turned on to start the temperature rise. When the outlet temperature reaches the set temperature (generally around 130 °C), start the material pump and dust removal system. When the pump pressure reaches 2 MPa, the spray gun is turned on to start granulation. After the equipment is running, the atomization and the working condition of the pump should be observed in time. If there is a gun blocking phenomenon, the nozzle should be cleaned or replaced immediately. After the equipment is in normal operation, it should also regularly collect materials, regularly check the operation of each system, record the process parameters, and pay attention to clean the vibration filter screen.
At the end of the granulation, the heating device should be shut down first to stop the gas engine operation. Then close the gun valve, replace the gun, unscrew the nozzle and rinse. When the inlet temperature is reduced below 100 °C, the operation of the blower and the blower can be stopped.
Then clean the remaining materials in the drying tower and the precipitator, turn off the dust collector and the air hammer, and finally turn off the main power supply to complete the production operation.
In case of emergency, the equipment must be shut down immediately. The blower and feed pump should be shut down first. If there is a sudden power outage, the gas engine should be pulled out to cool the tower naturally, then the drain valve is opened, the slurry in the slurry pipeline is drained, and the equipment is cleaned.
3 Maintenance and care
Granulation is an important part of the PTC production process. Maintaining the normal operation of the equipment is a necessary condition to ensure the stability of PTC production. Regular cleaning, maintenance and maintenance help to identify problems, resolve potential failures, reduce downtime, and ensure normal production.
If the drying equipment runs for a long time or is improperly operated, aggregates will appear in some equipments and affect normal operation. At this time, it is necessary to stop working for cleaning. For the cleaning of the aggregate in the drying tower, the cleaning door should be opened, the funnel-shaped bottom aggregate should be removed with a long broom, the discharge valve should be opened, and the tower should be washed with tap water. The removal of dust in the cyclone also requires opening the cyclone, sweeping the aggregate with a broom and, if necessary, flushing with water. For the cleaning of the bag filter, open the control switch, tap continuously, then open the cleaning door, hit the bag filter, and finally replace the filter bag. For the cleaning of the slurry pipeline system, the sewage valve of the two-way filter should be opened, the filter screen and the pipeline should be cleaned, and then the material pump should be opened to replace the pump tube, the pressure regulator package and the pipeline with water. After a period of time (usually about 600h), it is necessary to carry out the necessary inspection and maintenance of the spray granulation drying equipment. For the feeding system, check the filter, pipe, valve, nozzle, etc. to see if there is any blockage, regular cleaning, check the nozzle wear condition for timely replacement.