Vacuum dryer mechanical maintenance methods: vacuum dryer operation, first open the stirrer, add the material to be dried, and the feeding port closed. At the same time through the steam heating, heating steam pressure is generally 0.2 ~ 0.4Mpa (gauge pressure). Use vacuum pump to pump out water vapor and non-condensable gas, general material drying, the vacuum degree is about 700mmHg. The moisture evaporation intensity of this dryer varies with the nature of the material, humidity, heating steam pressure and vacuum degree and so on. For example, in the vacuum degree of 700mmHg, heating steam pressure of 0.2Mpa (gauge pressure), the potato starch from the initial moisture of 40% dry to 20%, the dryer's moisture evaporation intensity of 5~7 kg/m2-h.
Vacuum dryer operation than the box dryer labor intensity is low, can be recovered in the material of the wet usefulness of the operating conditions are good, the management of the more convenient. Its disadvantages are low production capacity, equipment structure is more complex, the agitator blade is easy to damage and so on. This kind of dryer is more used in dyestuff and pharmaceutical industry. For example, drying of reduced dye intermediates, anthraquinone sulfonic acid, reduced olive green R, salicylic acid intermediates, capron polymer, diamino anthraquinone and other materials. Vacuum harrow dryer equipment structure.