Vacuum dryer is composed of refrigeration system, vacuum system, heating system and electrical instrument control system. The main components are drying oven, condenser, refrigeration unit, vacuum pump, heating / cooling device, etc. Its working principle is to freeze the dried articles to below the three-phase temperature, and then sublimate the solid water (ice) in the articles into steam directly under the vacuum condition, and then drain the dry articles. After pretreatment, the materials are sent to the quick freezing bin for freezing, and then sent to the drying bin for sublimation and dehydration, and then packaged in the post-processing workshop. The vacuum system establishes a low pressure condition for the sublimation drying bin, the heating system provides sublimation latent heat to the material, and the refrigeration system provides the required cooling capacity to the cold trap and drying chamber. To obtain high-quality products, in addition to the need to know the theory and technology of freeze-drying, but also to the vacuum dryer vacuum pump use precautions to have a comprehensive understanding, let's take a look at it!

1. Check the oil level frequently. If it does not meet the requirements, it must be adjusted to meet the requirements. When the vacuum pump is running, the oil level to the center of the oil mark shall prevail.

2. Check the oil quality regularly and replace the new oil in time in case of oil deterioration to ensure the normal operation of vacuum pump.

3. The oil change period shall be considered according to the actual service conditions and whether it can meet the performance requirements, etc., and is determined by the user at his discretion. General new vacuum pump, when pumping clean and dry gas, it is recommended to change oil once every 100 hours. After the black metal powder is not seen in the oil, the oil change period can be appropriately extended in the future.

4. Generally, the vacuum pump of vacuum dryer should be overhauled after working for 2000 hours. Check the aging degree of rubber seal, check whether the exhaust valve plate is cracked, and clean the dirt deposited on the valve plate and exhaust valve seat. Clean the whole vacuum pump cavity parts, such as rotor, rotor, spring, etc. It is usually cleaned with gasoline and dried. After cleaning rubber parts, dry them with dry cloth. When cleaning and assembling, handle with care to avoid bumping.

5. If possible, clean the vacuum dryer tube to ensure that the pipeline is smooth.

6. After the re assembly, it should be put into trial operation. Generally, it is necessary to run for 2 hours without load and change the oil twice. Because there will be a certain amount of volatile matter left in the vacuum pump during cleaning, it can be put into normal operation after the operation is normal.

7. Check whether the pipeline and joint of vacuum pump of vacuum dryer are loose. Turn the vacuum pump by hand to see if it is flexible.

8. Add the bearing lubricating oil into the bearing body, observe that the oil level should be at the center line of the oil mark, and the lubricating oil should be replaced or supplemented in time.

9. Screw off the water diversion plug of the vacuum pump body of the vacuum dryer and pour water (or slurry).

10. Close the gate valve of water outlet pipeline, outlet pressure gauge and inlet vacuum gauge.

11. Jog the motor to see if the rotation direction of the motor is correct.

12. Start the motor. After the vacuum pump runs normally, open the outlet pressure gauge and the inlet vacuum pump. Gradually open the gate valve and check the load of the motor after it shows the appropriate pressure.

13. The flow and head of the vacuum pump of the vacuum dryer should be controlled within the range indicated on the label, so as to ensure that the vacuum pump operates at the highest efficiency point, so as to obtain the maximum energy-saving effect.

14. During the operation of vacuum pump of vacuum dryer, the bearing temperature shall not exceed 35C of ambient temperature and the maximum temperature shall not exceed 80C.

15. If the vacuum pump of vacuum dryer has abnormal sound, stop the machine immediately to check the cause.

16. When the vacuum pump of vacuum dryer is to stop using, close the gate valve and pressure gauge first, and then stop the motor.

17. In the first month of operation, the vacuum pump of the vacuum dryer changes the lubricating oil for 100 hours, and then changes the oil once every 500 hours.

18. The packing gland should be adjusted regularly to ensure that the leakage in the packing chamber is normal.

19. Regularly check the wear of the shaft sleeve, and replace it in time if the wear is large.

20. When the vacuum pump of vacuum dryer is used in cold winter season, after shutdown, it is necessary to screw off the drain plug at the lower part of the pump body to drain the medium completely. Prevent frost cracking.

21. The vacuum pump of the vacuum dryer is out of service for a long time. All the pumps should be disassembled to dry the water. The rotating parts and joints should be coated with grease, and properly kept.