Knowledge of the use and maintenance of vacuum dryers in the chemical industry

Vacuum rake dryer is widely used in organic semi-finished products and fuel drying operations in the chemical industry. It is a novel horizontal intermittent vacuum drying equipment. The wet material is evaporated by conduction, and the hot surface is continuously removed by a scraper agitator. The material on the container is moved in the container to form a circulating flow, and the water is evaporated and then pumped out by a vacuum pump. What are the disadvantages of structurally using vacuum rake dryers? Using latent heat to heat materials, the amount of steam consumed per kilogram of finished products is relatively small, generally 1.3-1.8kg of steam, and the water vapor pressure on the surface of the dried materials is much higher than that of vacuum rake dryers. The water vapor pressure in the evaporation space in the shell, the material to be dried can be slurry, paste, granular, powder, or fibrous. The main disadvantages of vacuum rake drying are: complex structure and high cost.

Due to the intermittent operation, the drying time is long and the stock output is low; and because it is not easy to clear the material, it is not suitable for the production of frequent replacement of varieties. At the same time, in order to ensure the vacuum degree, the vacuum device must be maintained and overhauled frequently.
Maintenance and maintenance of vacuum rake dryer:
1. Start the motor. When the vacuum pump is running normally, open the outlet pressure gauge and the inlet vacuum pump. After seeing the appropriate pressure, open the gate valve gradually, and check the load of the motor at the same time.


2. Jog the motor to see if the direction of the motor is correct.
3. Check the oil level position frequently, and adjust it to meet the requirements if it does not meet the requirements. When the vacuum pump of the vacuum rake dryer is running, the oil level should reach the center of the oil standard.

Frequently check the oil quality, and replace the new oil in time if the oil is found to be deteriorated, so as to ensure that the vacuum pump of the vacuum rake dryer works normally. Add bearing lubricating oil to 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 replenished in time.
4. Close the gate valve, outlet pressure gauge and inlet vacuum gauge of the water outlet pipeline.


5. Check whether the vacuum pump pipeline and joints are loose. Turn the vacuum pump by hand to see if the vacuum pump is flexible. Under normal circumstances, the vacuum pump should be overhauled after working for 2000 hours, check the aging degree of the rubber seal, check whether the exhaust valve is cracked, and clean up the dirt deposited on the valve and exhaust valve seat.

Clean the parts in the entire vacuum pump cavity, such as rotors, rotary vanes, springs, etc. Generally, it is cleaned with gasoline and dried. After cleaning the rubber parts, wipe them dry with a dry cloth.

When cleaning the assembly, handle it with care and be careful not to scratch it. Clean up the tube if possible to ensure the smooth flow of the pipeline.
6. The oil change period is determined by the user according to the actual use conditions and whether the performance requirements can be met.

Generally, when a new vacuum pump pumps out clean and dry gas, it is recommended to change the oil every 100 hours or so. After no black metal powder can be seen in the oil, the oil change period can be extended appropriately in the future.
7. Unscrew the water diversion screw plug of the vacuum pump body, and pour water (or slurry).

After reassembly, a trial run should be carried out. Generally, it must be run dry for 2 hours and the oil should be changed twice. Because there will be a certain amount of volatile matter in the vacuum pump during cleaning, it will be put into normal work after it runs normally.