the correct operation and use of new die of pellet mill cpm7726制粒机用环模

1. adjustment after installation of new die

1）      adjustment after installation of pellet mill

in order to make the overload device of pellet mill function, you can move with hand the limit switch by the side of rear shear pin flange housing and observe if main machine can stop while it is running. the rotational direction should be correct（die rotates clockwise） , feeder and mixer should not feed materials reversely, and feeding controller should be able to control the materials flow freely.

after the normal racing of new pellet mill, do not be eager to feed materials for pelleting, the other parts of pellet mill should also .be adjusted. first of all, open the operating door of pellet chamber to check if main shaft moves axially. if so, you should adjust the lock nut at the rear of main shaft until no movement. but lock nut cannot be too tightened to avoid too high temperature rising on the head of main shaft after the starting of machine. secondly, check two rollers. roller should rotate flexibly without any axial movement. if so, you should adjust the lock nut of roller shaft until the good conditions. besides, lock washer should be well locked to avoid the looseness of lock nut. and grease should be added enough to avoid the damage of bearing due to too high temperature rising and lack of grease.

2）        correct control of clearance between rollers and die

too small clearance will result in the easy wear of die and rollers and big noise, and too big clearance will affect the output. generally the clearance should be controlled to 0.05-0.30mm in accordance with the die hole size. when adjusting plug rule can be used to measure, estimation with eyes is feasible without plug rule. taking new die and rollers for example, it is better through estimation with eyes that die just touches rollers and die cannot drive rollers without materials, and it is especially emphasized that smaller clearance of new die would be better- when adjusting the rollers direction should be consistent, adverse adjustment for two rollers is not allowed, otherwise uneven clearance will result there from so that die moves up and .down greatly. after adjustment all fasteners should be tightened so as not to fall down and damage the machine. feeding wiper should be well adjusted, otherwise it is difficult for materials to enter between rollers and die fully, part of materials come out of the feed cone. forming small pellet with high powderization rate.

the adjustment result should be that feeding scraper between curve of the upper edge of wiper and die and feed cone is basically controlled to 2-3mm, the front end of wiper should not stretch into die beyond the groove of die inner hole.

2. procedures for use and test of new die

after adjustment of pelleting system, the machine can be normally started for pelleting. when starting the machine, the outer discharging door on the operating door should be opened, if outer discharging door is not available, you can open the operating door. first start the main machine, then start mixer and feeder after normal running. feeding should be slow at first, open the steam valve at the same time when materials enter the mixer. the applicable saturation steam pressure should be 0.2-0.4 mpa. generally the moisture of materials is about 12% before pelleting and it is up to about 15% after the addition of steam with the temperature reaching 80℃.too high moisture will make materials agglomerate on the surface of die and be difficult for pelleting and block the die holes;too low moisture and insufficient softening of materials will result in the increase of pelleting resistance and decrease of capacity, simultaneously easy production of high temperature so that materials are burnt with smoke until pellet cannot be produced. generally the moisture content of a batch of materials would provided be tested quickly in order to correctly control the steam volume. during the actual operation, the steam volume is controlled generally by means of experience and feel. when materials into which steam is added come from the mixer, extraction some at first, then snatch at materials for observing: it is good that materials can be matched into a ball with a light snatch and spread with a touch after hand looses, if materials cannot be snatched into a ball, that means moisture is too low and pelleting requirement is not reached; if ball cannot spread, that means moisture is too high. of course different formulation materials require different steam volume. operator should try to find out the laws, constantly accumulate the experience in practice and grasp and use by means of feel and eyesight.

after being conditioned, materials can enter the pellet chamber. the speed is from slow to fast and materials flow increase gradually. after materials enter the pellet chamber, first observe if there are pellet coming out of die holes and carefully pay attention to the current change. if pellets can come out of die holes normally, current fluctuates within a narrow range and the rated current is not reached, you can increase the materials flow and appropriate steam volume until the rated current is reached, in case materials can enter the pellet chamber, but there is no pellets coming out of die holes and current keeps rising in the meantime, you should open the outer discharging door and observe if current dr-ops down and a few pellets come out of die holes, you can close the outer discharging door for continuous pelleting, in the event current doesn"t dr-op down yet with the stoppage of feeding and even keeps rising, you should stop the machine and check the reasons. open the operating door, get rid of the remainder in the pellet chamber, again start the machine in accordance with the above method until the normal pelleting. before stopping the machine and after stopping the feeding, shut off the steam, mixer and feeder, and adjust the feeding controller to zero. finally make main machine finish pelleting the original materials in the pellet chamber, then feed with hands the oily materials （e.g rice and fine bran） from the top of operating door to extrude the materials inside the die and let oily materials fill up die holes. after 1-2 minutes of contineous running, stop the main machine and get rid of the remainder in the pellet chamber in preparation for next starting. the purpose of filling with oily materials inside the die is to prevent materials in the die holes from hardening so that pellets can easily come out of die holes next time. attention please, new die would better be equipped with new rollers for easier pelleting.

3. main reasons of die holes blockage and cleaning method besides the insufficient finish owing to the manufacture, there are still many reasons causing mew dies not to produce pellets. for example, die is laid aside for a longer time after its purchase, causing rust on the surface of die holes. taking other examples, the fineness of materials not consistent with die holes, the moisture of materials is beyond or lower than that required for pelleting, and so on.. of course the reason of unskilled operation is included, if you have not grasped the operation essentials and features, it is difficult, especially for customers who use the pellet mill for the first time, to made die produce pellets normally. generally speaking, if the fineness of new die is not sufficient indeed, oily materials should be used firstly for trial production and added with appropriate emery （if emery is not available, sand can replace）, about 30%, but it should be mixed evenly. then start the main machine. after the main machine runs normally. feed with hands from the top of operating door and observe the current change. feed the materials from less to more and produce the pellets repeatedly. during the production, keep observing the pellet fineness and current change, and stop the machine in time for checking and removing when finding abnormal conditions. when testing new die, if it is found that pellets are becoming harder and harder, powder is becoming more and more, temperature is becoming higher and higher, thus oily materials should be added with appropriate oil and moisture after some time of test（about 30 minutes）,if materials of the same quantity are fed into the pellet chamber, current is greatly lower than that at the time of initial feeding, and most of die holes have produced pellets, then you can stop the machine, open the operating door and observe the pelleting circumstances. generally it is not bad that pelleting rate is more than 90%. otherwise, again prolong the test time in accordance with the above method until the requirements are reached.

when new die is blocked or die is reused after a longer time of idle and cannot produce pellets, the general method to be used is to drill the materials out with drill bit or beat them out with iron nail. but it is not easy to deal with die holes below 2.5mm, drilling with hand drill has various unfavourable factors. first of all, drilling with vertical degree not in conformity to requirements will damage the original finish easily and cause easy break of drill bit and die holes blockage. being such a case, the method is to boil die with engine oil. the concrete method is: put waste engine oil to an iron tray, and put in the blocked die to make it fully sink into engine oil. then heat the bottom of tray until the materials in die holes crack, thus die can be taken out and reused after cooling. after adjustment start the machine pertaining to previous operation method, thus the materials blocking the die holes can be quickly cleared away, and the original finish of die will not be damaged, if you boil the second die as soon as you will have finished the boiling of the first one, generally 15 minutes will be enough. the first blocked die needs a longer tune due to low oil temperature at the beginning. cpm7726制粒机用环模

generally speaking, new dies should be purchased from the specialized manufacturer. that will benefit the users.