I Feed cannot enter the ring die.

Cause

1. Bridged inlet of the feeder  

2. Clogged conditioner    

3. Failure of the feeder’s driving device

Solution

1. Clean the inlet.

2. Clean the conditioner.

3. Check the driving device for feeder.

II Material can enter the ring die, but cannot be pelletized.

Cause

1. Worn-off of press rollers and ring die 

2. Too many die holes are clogged.  

3. The feed formula is changed. 

4. The clearance between the press rollers and ring die is too large. 

5. Improper water content in feed

Solution

1. Replace the press rollers and ring die.

2. Remove the feed and impurity from the die holes.

3. Install the ring die properly for the feed formula to be processed.

4. Readjust the clearance between the press rollers and ring die.

5. Adjust steam amount correctly.

III The pellet mill cannot be started up.

Cause

1. The press rollers and ring die in pelletizing chamber are clogged. 

2. Limit switches cannot touch the brake plate or the operation bar, or have been damaged.

3. Circuit failure

Solution

1. Remove the feed from the pelletizing chamber.

2. Check the limit switches for mounting status.

3. Check the circuit.

IV Load of pellet mill fluctuates unreasonably or the pellet quality is uneven.

Cause

1. Steam supply is not enough or the pressure changes sometime. 

2. Unstable conveying of material

3. Deflecting plate scrapers are worn which causes uneven feeding.

Solution

1. Check the steam pipelines.

2. Adjust the feeding rate.

3. Replace the deflecting plate scraper.

V Pellet mill stops during working

Cause

1. V-belts are not tensioned enough, which makes the speed controller actuate. 

2. The parameter of speed controller is not reasonable. 

3. V-belts are seriously worn off partially or completely or broken.

4. The main shaft rotates and limit switch escapes because of overload or a foreign matter is entrapped between the press rollers and ring die.

5. Circuit failure

Solution

1. Readjust the tension of V-belts or check the pressure value on the pressure gauge of hydraulic system, reset the pressure value if necessary (Be careful when adjusting). 

2. Reset the parameter.

3. Replace the V-belts completely, not partially.

4. Reset the main shaft and limit switch. 

5. Check the circuit.

VI The pellet mill is clogged frequently

Cause

1. Deflecting plate scrapers are worn and material is distributed unevenly. 

2. Press rollers are worn off. 

3. A press roller gets stuck. 

4. The installation positions of the deflecting plate scrapers are incorrect. 

5. The moisture content in feed is too high.

Solution

1. Replace with new deflecting plate scrapers. 

2. Replace with new press rollers. 

3. Check the press rollers. 

4. Reassemble the deflecting plate scrapers.

5. Decrease the moisture content.

VII  Pellet mill is smoking

Cause

1. The scrapers are worn off and there is a layer of hard material formed between the supporting plates of the rotors and the press rollers. 

2. Tension of V-belts is not enough. 

3. Hard material deposited behind the back supporting plate, which makes the main shaft lack of lubrication.

Solution

1. Install a new scraper.

2. Tighten the V-belts.

3. Clear away hard material and lubricate the main shaft till lubricating grease overflows from the back.

VII  Ticks are heard when the pellet mill makes each rotation.

Cause

Tramp metal in the ring die

Solution

Check the inner surface of the ring die and clear away the tramp metal.

IX V-belts are slipping when they are under full loading or overload a bit.

Cause

1. Tension of V-belts is not enough 

2. The length of V-belt in a group is different.

3. V-belt is contaminated by grease.

4. Wrong location of V-belt

5. The external form of V-belt is incorrect

Solution

1. Readjust the tension of V-belts.

2. Replace with a complete set of belts of the same size.

3. Clean the V-belts and pulley.

4. Calibrate the motor and middle pulley.

5. Use qualified V-belts

X  Output of the pellet mill is not enough, while the main motor works under full load.

Cause

1. Too much steam added (only for materials sensitive to temperature and humidity)

2. The ring die is too thick

3. Bad steam quality and too much water content

4. Material is not sufficiently conditioned

5. The clearance between the press roller and ring die is too big

6. The press roller and ring die are over worn

7. Bad formula or too big grinding pellet

Solution

1. Reduce the steam adding amount.

2. Use the ring die with a depth proper for the material to be processed. 

3. Readjust the steam supply system. 

4. Increase the steam amount or the extend the conditioning time. 

5. Readjust the clearance. 

6. Replace the press rollers and ring die.

7. Adjust the formula or replace with a sieve with smaller apertures in the hammer mill.

XI  The ring die is broken when worn to a certain extent.

Cause

1. Foreign matters in the die   

2. Ring die is too thin.   

3. Fixing of the ring die is out of order.

Solution

1. Perfect the material cleaning operation.  

2. Use a thicker ring die with holes with step relieves.

3. Check whether the driving rim of the ring die and the fixing bolts are locked sufficiently or not, and replace the driving rim of the ring die if necessary.

XII  The bearings of the press rollers are vulnerable.

Cause

1. There are hard foreign matters in the feed.

2. The clearance between the press roller sand ring die is too small.

3. Improper lubricating grease is used.

4. Lubricating grease applied for the press rollers is insufficient.

5. Bad bearing end cover and seal ring are used.

6. Unqualified press roller bearings provided by other suppliers are used.

Solution

1. Improving material cleaning performance.

2. Adjust the clearance between the press rollers and ring die.

3. Apply lubricating grease as designated.

4. Apply enough lubricating grease as designated.

5. Replace the end cover of bearing and seal ring.

6. Use the bearings provided by normal manufacturers