Rake tooth structure and precautions for rake dryers

Rake Tooth Structure

 

The rake tooth device of the dryer consists of two sets of rake teeth, one facing left and one right, mounted at opposite angles on either side of the drive shaft. Each rake tooth has a square hole at its head to mate with the drive shaft, with adjacent rake teeth positioned 90° apart during assembly. The ends of the rake teeth come in two shapes: one flat and paddle-shaped, and the other also flat but irregularly shaped. Both are at a certain angle to the drive shaft's centerline (i.e., left and right). The paddle-shaped rake teeth are used in the middle of the equipment, while the irregularly shaped rake teeth are used at the ends of the dryer to fit the inner wall surface. The rake teeth are installed on one side, and the right-hand rake teeth on the other. Therefore, when material is added, the rotation of the rake teeth causes the material to move to both sides and then back to the center, resulting in uniform mixing. This prevents overheating when the material contacts the inner wall of the shell and also achieves a pulverizing effect, increasing the aeration surface and promoting the drying process.

 

In addition, within each of the four quadrants of the rake teeth, a seamless steel pipe, parallel to the main shaft and closed at both ends, is placed for striking the walls of the rake, which helps in cleaning and crushing materials. The rake teeth are generally made of cast steel. The drive shaft bears torque and bending moment during operation. Besides meeting certain strength requirements, the drive shaft must also have sufficient rigidity to prevent it from jamming against the inner surface of the casing. The drive shaft is generally made of grade steel.

 

8 Important Precautions for Rake Dryers

 

1. Heating or cooling the dryer should be done slowly. Users should choose appropriate heating and cooling rates according to the situation.

 

2. During equipment operation, sampling should be performed according to the standard procedure. After sampling, the machine should be restarted.

 

3. Rolling bearings should use MOS2 composite grease (ZFG-IE) with a maximum temperature of 150 degrees Celsius. Check at least once a month. Replace with new grease when it dries out.

 

4. Maintenance of the cylindrical gear reducer should be performed according to its instruction manual. 5. After each drying cycle, the filter inside the tank should be cleaned of adsorbed powder to ensure unobstructed filtration.

 

6. The mechanical seal or packing seal between the main shaft and the tank body should be inspected regularly. If leakage is found, repair or replace the seal immediately.

 

7. The equipment should be inspected and repaired every six months to one year. During maintenance, the original assembly method and tolerance requirements must not be altered, and appropriate lubricating oil should be added as specified.

 

8. Special note: The equipment must be reliably grounded from the time of installation and use.