1. Working principle
→
raw materials → → → → extract concentration → → → → → vacuum dry
In chemical process industries, we are faced with difficulties in drying materials due to high toxic contents,hygroscopic in nature, heat sensitive.
To solve the above problems, vacuum dryers are used where the boiling point of the materials to be dried is brought down and the entire system is in a closed loop. No contamination occurs, due to the closed arrangement. Any vapours evolved during the drying process is cooled down through a connected Heat Exchanger and collected in a reciever.
Our YZG/FZG vacuum dryer is basically a tray dryer working under vacuum conditions. It dries on the conduction principle. There are a number of shelves inside the dryer on which the product laden trays are placed. The steam / hot water starts circulating inside the shelves in a serpentine manner. Due to this configuration, the heat transfer from the shelves to the trays is quite fast. The heat is transferred to the product from the shelf on which it is placed due to conduction and from the shelf above due to radiation. The boiling point of the product is brought down considerably due to vacuum.
1.Characteristics of Microwave Vacuum Dryer:
Ⅰ.Compared with conventional microwave equipment:
1)Low temperature:under one atmospheric pressure (101.3 kpa), the boiling point of water is 100 °C.But under 0.073 of one atmospheric pressure(7.37 kpa), the boiling point of water is only 40 °C.It is on negative pressure condition when using microwave vacuum device,material can be processed under low temperature.So the quality of the material can be guaranteed tremendously. The machine is especially suitable for drying material which need to dry in the low temperature, such as herbal extract,ginseng,ect.
2)Pressure:In negative pressure environment with microwave vacuum device,moisture evaporates faster in the lower temperature.
Ⅱ.Compared with conventional vacuum drying equipment:
1)Penetration:because it is in vacuum situation when using conventional vacuum drying equipment,heat cann't transfer in the form of convection and can only conduct.So the heating speed is slow,drying time is long and the energy consumption is excesive.However,Microwave vacuum drying equipment adopts radiation way to transfere energy and it heat wholly without any medium.Itavoids the above shortcomings.
2)Evenly:microwave heating is in and outside of the material at the same time,the temperature difference is very small in and outside of the material.So it is more evenly when drying materials,and the heating efficiency is greatly increased.
3)Quickly:because of the penetration of the microwave and the radiation way to transfere energy, materials is heated inside and outside at the same time.Thus the drying speed is greatly improvedl.
2.Technical parameters:
Description/Specification | YZG-600 | YZG-1000 | YZG-1400 | FZG-15 |
internal size of drying cabinet(mm) | φ600×976 | φ1000×1527 | φ1400×2054 | 1500×1400×1220 |
external size of drying cabinet(mm) | 1153×810×1020 | 1693×1190×1500 | 2386×1657×1920 | 1513×1924×2060 |
layers of drying holder | 4 | 6 | 8 | 8 |
layer distance(mm) | 81 | 102 | 102 | 122 |
size of drying pallet(mm) | 310×600×45 | 460×640×45 | 460×640×45 | 460×640×45 |
numbers of drying pallet | 4 | 12 | 32 | 32 |
pressure inside the drying pipe(MPa) | ≤0.784 | ≤0.784 | ≤0.784 | ≤0.784 |