1.Concerns in operation of pellet mill

Pellet mill is main key equipment for all feed enterprises,pellet mill can operate normally or not, affect the economic profit of enterprise directly,so the right operation is very important.                                                     

Firstly, operators should be conscientious in their work,strictly adhere to operating rules to operate pellet mill, start and stop pellet mill must follow procedures.                                                                   

① Keep steam dry, ０．３－０．４KG pressure enters into the conditioner.           

② Adjust the distance between the die and the roller. Usually is ０．２ｍｍ－０．５ｍｍ， the pressure die can bring the pressure roller to run slightly, not too tight or too loose,too tight can shorten life of pressure die, too loose cause pressure roller to slip.                                                                

③ The raw material moisture is required between １２％－１３％,raw material moisture after conditioning is about １４％－１４．５％, must feed equally.       

④Current controlled by stipulated load,absolutely can't produce in long time with over load, that is the main reason causing pellet mill damage.                                

⑤Notice current fluctuations in normal production,when discover abnormity, stop pellet mill immediately to check.                                                           

⑥ After new pellet mill put into production,the pellet mill gear box continually work 500 hours, engine oil should be changed,according to production situation, usually change engine oil once per ３－６months, change ６８＃ engine oil or １００＃－１２０＃ industrial gear oil.                                                    

⑦ When pellet mill is blocked, pressure roller must be adjusted loose, restart pellet mill untill the inner wall of pressure die is clean. Absolutely prohibit  forced start in the blocked status, use tube spanner to move gear shaft is not allowed. Pellet mill in normal working condition, pressure roller added lubricant grease once per two hours.                                                                   

⑧ Check the worn situation of pellet mill easily damaged parts frequently,avoid sudden fault and ring die cracking.
The reasons of ring die cracking: ａ、worn encircling hoop can't hug ring die tightly, ｂ、worn drive key and pressure die lining make pressure die can't fix position,ｃ、main shaft loose cause pressure roller jumpiness to beat ring die,　            ｄ、foreign matter enters into ring die, ｅ、forced start because of ring die blocked ｆ、the ring die has quality problem

2.Analysis of  pellet mill difficult discharging and low output

① Use new ring die, check ring die compression ratio if matches producing materials firstly,the compression ratio is over big,pressed pellet is hard and low output,so the ring die compression ratio must be changed.                                        

② Check smoothness of ring die inner bore and ring die if out of round,some inferior ring dies with coarse inner bore,ring die is out of round cause pellet is not smooth and equal, difficult discharging and low output, so must use high quality ring die.

③ If ring die has been used in a period of time, must check inner wall taper bore of ring die and pressure roller is worn or not, rework and repair ring die if worn taper bore, which has a great influence on the output, worn pressure roller must be changed.                                                                            

④ Adjust the clearance between ring die and pressure roller accurately, the small clearance makes pressure roller increase weight rubbing ring die, shorten the ring die using time,the over large clearance causes pressure roller to slip,discharging is not smooth and output is reduced.                                                         

⑤ Notice conditioning time and quality of raw material, especially to control raw material moisture before entering pellet mill,raw material moisture before conditioning is usually １２％－１３％，keep moisture about １４％ after conditioning,if raw material moisture is too high,the conditioning temperature will be affected,conditioning efficiency is bad,raw material enters ring die will occur blocking and slipping.                                                          

⑥ Check material distribution in ring die,can't let all material run in one side, if happen this situation, must adjust the position of feeding scraper,let material distribute equally in ring die,not only lengthen the useful life of ring die, but also discharging is smooth.                                                        

⑦ Pellet mill operates with problem, bearing runs in out circle causing pellet mill being powerless in work,unstable current and output is reduced.
3.Analysis of pellet mill large vibration,big noise and operation abnormity.

① Pellet mill operate improperly and operating current brings fluctuations, maybe bearing in some part has problem,so the operating current is too high, please stop pellet mill to check or change bearing.                                                  

② Ring die blocking or just some part of die bore discharging.Foreign matter enters into ring die,ring die is out of round,the clearance of pressure roller and pressure die is too tight,worn pressure roller or bearing damage of pressure roller can't run, all can cause pellet mill to vibrate, please check or change ring die or adjust pressure roller clearance.                                                 

③ Coupling ajustment is not balanced,high and low and left and right has a deviation. Pellet mill vibrates and oil seal of gear shaft is easily damaged,so the coupling should be adjusted in horizontal line.                                            

④ Main shaft is not tight,especially D type or E type pellet mill,loose main shaft causes shaft forward and downward play, pressure roller swings obviously,pellet mill vibrates with big noise and hard discharging,the disc spring and round screw in main shaft tail should be tightened.                                                       

⑤ Worn big and small gears,or change single gear also cause big noise,need running-in duration.                                                                   

⑥ The unequal cutting of conditioner discharging mouth makes operating current  fluctuate wildly,need adjust conditioner blade.                                          

⑦ The new ring die must be equipped with new pressure roller, dispose a proportion of sand and chaff to grind,use the new ring die after polishing,prohibit using inferior ring die.                                                                        

⑧ Strictly control conditioning time and temperature,control entering material moisture at anytime,too dry or wet material can cause abnormal discharging and pellet mill to operate abnormally.                                                            

⑨ Steel-framed structure is not firm, so steel frame vibrates when pellet mill operates normally,pellet mill produces resonance easily, must reinforce steel-framed structure.                                                                

⑩ The tail of conditioner is not fixed or fixed not firmly cause vibration, so the tail of conditioner should be reinforced.                                                 

(11) The reasons of pellet mill oil leakage: worn oil seal, oil level is too high, damaged bearing,unbalanced coupling,body vibration and forced start.