Comprehensive Guide to Rotary Dryer Alignment

Rotary dryers are indispensable industrial equipment in various industries, widely used in mining, building materials, chemical, food, medicine and other fields, responsible for drying a variety of granular, lumpy and powdery materials. For plant managers pursuing efficient production, it is vital to extend the service life and reliability of rotary dryers. Alignment is an often overlooked but critical aspect of this.

Alignment is the key to rotary dryer maintenance, ensuring that the cylinder is in the correct position on its base to avoid misalignment. Neglecting alignment can lead to a range of serious consequences, leading to safety hazards and ultimately unnecessary damage to the plant.

Rotary kiln dryers for industrial production

Why is rotary dryer cylinder alignment critical?

The alignment of a rotary dryer is critical to its performance and longevity for several reasons.

Ensure structural stability: Correct alignment ensures that the rotating drum remains structurally stable and is not subjected to excessive mechanical stresses due to uneven load distribution.

Reduces mechanical stress: Good alignment reduces unnecessary mechanical stress due to constant motion and thermal stress, which is particularly important for rotating drums that are subjected to long periods of high temperatures.

Prevents component damage: Misalignment can lead to rapid wear or damage to mechanical components (e.g. bearings, gears, etc.) and drum shells, which is a common cause of premature equipment failure.

Improved operating efficiency: Properly aligned rotating drums allow for more efficient heat transfer and material handling, resulting in increased drying efficiency.

Extended equipment life: Correct alignment can significantly extend the life of a rotating drum by reducing unnecessary wear and stress.

Rotary Dryer Maintenance

Causes of misalignment

Dryer misalignment is when the dryer cylinder is not in the correct position on its base, resulting in deflection or misalignment between the cylinder and the base. Misalignment will lead to increased wear and tear of the dryer and components, shorten the service life of the equipment, reduce operational efficiency, increase maintenance costs, and even cause hidden safety hazards.

Although rotary dryers are always (or should be) correctly aligned during commissioning, after a period of time many factors can cause the dryer to become misaligned and thus require re-alignment.

Why does misalignment occur?

Common causes of misalignment include:

  • Settling of the base
  • Tyre and/or bearing seat wear/smooth finish exceeding 10% of its original diameter
  • Changes in process conditions (feed, capacity, temperature, material characteristics, etc.)
  • The drum has undergone any major repairs or parts replacement
  • Failure to properly maintain proper “float” between thrust rolls
  • Excessive tilting or shimming of the bearing housing
  • Wet operating conditions
  • Poor maintenance hygiene or excessive dust, especially in and around the bearing housing pits

Signs of rotating drum misalignment

Misalignment can manifest itself in a number of ways. Common signs of drum misalignment include:

  • Abnormal chattering, grinding or other unusual sounds
  • Visual wear or damage to tyres and/or support wheels
  • Visual wear or damage to gears and/or rings
  • Visual wear or damage to thrust rollers
  • Poor contact between the tyre and the support wheel, at the gear meshing point or around the thrust roller

It is therefore recommended that a rotary dryer audit is carried out by the OEM or a qualified service provider to identify any potential problems. Not only will they be able to identify the problem, but they will also be able to determine the root cause so that misalignment can be avoided again after the drum has been realigned. As misalignment can have a variety of causes, it is vital that the root cause is identified.

fertilizer production line rotary drum dryer

Alignment method of rotary dryer

At present, there are two main methods for rotary drying cylinder alignment: manual alignment and laser alignment.

Manual alignment

Manual alignment is a traditional alignment method, which is done manually by trained technicians using measuring tools and calculators. The specific steps are as follows:

  • Measure the points of the cylinder to determine their coordinates relative to the axis of correct alignment.
  • Calculate from the coordinates the base adjustment required to bring the cylinder back into alignment.
  • Adjust the base to bring the cylinder into alignment.

The advantages of the manual alignment method are low cost and ease of operation. The disadvantages are lower accuracy, time-consuming and labour-intensive, and easily affected by human factors.

Laser alignment

Laser alignment is a modern alignment method that uses a laser tracking system to measure various points of the cylinder and computer software to calculate the base adjustments required for alignment. The steps are as follows:

  • Place the laser tracking system at various points on the barrel.
  • Measuring the coordinates of the barrel, the diameters and end profiles of the tyres and bearing housings using the laser tracking system.
  • Calculate the datum adjustment required for alignment using computer software.
  • The datum is adjusted to bring the barrel into alignment.

The advantages of the laser alignment method are high accuracy, speed, efficiency and independence from human factors. The disadvantage is that it is costly and requires specialised equipment and technicians.

Suggestions for selecting the method

In practical application, the appropriate alignment method should be selected according to the specific situation. If the budget is limited and the requirement for accuracy is not high, the manual alignment method can be chosen. If the requirements for accuracy and efficiency are high, the laser alignment method can be chosen.

Rotary Kiln Dryer Manufacturer

What does the alignment process involve?

The alignment process consists of three steps – inspection, adjustment and maintenance – designed to ensure that the barrel is correctly aligned with the base and to eliminate any potential problems.

The main elements of the calibration include:

  1. Checking the operation of the barrel to confirm that there are no misalignment issues.
  2. Measuring the coordinates of the barrel using a laser tracking system and calculating the required adjustments.
  3. Adjusting the base and trunnion bearings to bring the barrel into correct alignment.
  4. Check the float between the thrust rollers and make any necessary adjustments.

Calibration is a specialised task and needs to be carried out by trained technicians. Regular calibration can effectively improve the operating efficiency of the drying cylinder, extend its service life and reduce maintenance costs.

How to prevent misalignment?

In order to prevent misalignment of the dryer, the following should be noted:

  1. Select a soil base with sufficient load-bearing capacity and regularly check the settlement of the base.
  2. Regularly check the wear and tear of tyres and/or bearing housings and replace or repair them in time.
  3. The position of the cylinder should be readjusted when process conditions change.
  4. When repairing or replacing parts, it should be carried out in strict accordance with the operating procedures and the position of the cylinder should be adjusted with professional measuring tools.
  5. During the operation of the dryer, impact or other accidental shocks should be avoided.

Regular inspection and maintenance of the dryer alignment is vital to effectively extend its service life, improve operational efficiency, reduce maintenance costs, and ensure safety.

Conclusions

Correct alignment is essential to maximise the life of your rotary dryer and minimise unnecessary maintenance costs and downtime. Choosing an experienced service provider for alignment and other rotary dryer services will ensure that your dryer remains in optimum operating condition.

TONGLI has many years of technical accumulation and production experience, and is committed to providing customers with high quality rotary dryer products and services.

Not only can we provide high quality standard products, TONGLI can also provide customised services including size, logo and packaging to meet the diversified needs of customers.

Whether it is product manufacturing, customised service or maintenance support, TONGLI can provide a full range of solutions and become a reliable partner in the field of rotary dryers.

When you choose TONGLI, you choose professionalism and reliability. Contact TONGLI today for professional rotary dryer service and support!