The structure and working principle of the machine are mainly composed of the working parts such as the feeding part, the feeding part, the barrel part and the discharging part, and the transmission parts such as the uranium bearing part, the transmission part, the reducer and the coupling. The cylinder is welded with steel plates, and the two ends are respectively connected with the hollow shafts of the inlet and outlet by bolts, and horizontally supported on the two bearings, and the bushings are replaced inside the hollow journals of the inlet and outlet. And use him as a passage for feeding and discharging. Simplified inner wall with a high manganese steel backing plate and white iron. The cylinder contains a certain amount of grinding media (steel balls) and materials to be ground. When the simplified body rotates around the horizontal axis at the correct speed selected, the centrifugal force acts to raise the particle point of the mixture to a certain height in the cylinder body, and then breaks away from the inner wall of the cylinder and falls along the trajectory of the throwing line. Grinding, on the one hand, is broken by the impact of the heavy medium falling on the object. On the other hand, the material is crushed between the medium and the medium and the inner wall of the medium and the body, and the material is rolled and ground in the simplified body. Grinding machine, the material to be ground is continuously and continuously given from the feeding end of the mill, and the finely-grounded product is boosted by continuous feeding of materials, hydraulic (wet production) or wind (dry production) and lifting of the grid plate. The action is discharged from the other end of the mill.
1. Use of ball mill
(1) Preparation before starting:
1. Check if the lubricating oil at each lubrication point is properly oiled. If it is not enough, add it.
2. Check if the ball filling rate in the ball mill meets the requirements.
3. Check whether the bolts on the grinding body lining bolts, the grinding head and the barrel connecting bolts are loose and securely tightened.
4. Secure the manhole cover securely and tightly.
5. Check for leaks in the simplified bolt holes and manholes and remove them.
6. When starting the test for the first time or after stopping for a long time, firstly put a small amount of lubricating oil on the hollow bearings at both ends, and grind it with a manual disc for one week, or “jog†for one revolution to confirm that there is no abnormality.
7. Contact the relevant work positions before and after, and get the signal to allow the start to start the mill.
(2) The order of starting:
1. Start the powder output device.
2. Start the ball mill.
3. Start the feeder.
(3) The sequence of shutdown:
1. Stop the feeder.
2. Stop the ball mill. Long-term stop grinding should empty the steel balls and materials.
3. The conveyor continues to run until the material on the machine has been discharged and then stopped.
4. The ball mill should pay attention to the phenomenon:
The important parameters that the operator must master to adjust the mouth frequently are the important content that directly reflects the operation level of the ball mill and the utilization rate of the grinding. Mainly: the size of the water supply of the ball mill and the size of the flushing at the discharge port of the ball mill. Give the amount of minerals.
Ball mill bulging: It has a great relationship with the quality of the ball mill produced by the manufacturer and the length of the ball mill used by the user. The harbinger of the ball mill is: the first one is to see if the ball mill gives the mine mouth, and the other is to listen to the ball mill sound. The ball mill is swollen, the sound becomes small and boring. The third is to look at the ball mill current control cabinet. In particular, if the ball mill is swollen, its current value becomes smaller. The principle is: the ball mill is swollen, because the mine in the ball mill There are many sites, the steel ball and the ore are running together with the barrel of the ball mill, and the ore size of the ball mill discharge port becomes thicker. At this time, the ball mill does less work, and the electric energy is converted into kinetic energy, and the electric energy is correspondingly smaller. When the voltage is constant, the electric energy becomes small, and the change is caused by the current value becoming smaller.
3. The practical application of the ball mill
3.1 Ball mill grinding control difficulty:
1) The existing ball mill has a significant variation in terms of its operating characteristics. It is based on the amount of material in the mill. However, due to the complicated operating environment in the ball mill and the large measurement error. Therefore, the program may have certain limitations.
2) The ball powder control system of the ball mill is actually a time-varying system with multiple inputs, multiple outputs, multi-variable, strong coupling, large inertia and large delay. Using the commonly used PID control to forcibly split the relationship between the variables, not only does not get good results, but also easily cause system instability.
3) The milling control of the ball mill, in addition to the amount of controlled parameter feeding, the disturbance of the supply air volume. It is also affected by the amount of steel balls, the particle size of the materials, and the water content.
3.2 Process of existing milling system:
3.2.1 Operation of the general milling system The first is to use the pressure difference between the inlet and outlet of the ball mill as the control parameter; the second is to use manual operation and rely on the operator's experience for control. These two methods have low control precision, and the milling powder yield and quality are difficult to control, which has a great impact on the quality of the product.
3.2.2 The composition of the automatic control system: The control system consists of two parts, software and hardware, which are described as follows:
A. Software composition of the control system:
The software control strategy is intended to adopt a human-like intelligent control scheme. It is based on the principle of intelligent control, mimicking the human mind to intelligently decouple the ball mill to ensure the safe and reliable operation of the ball mill. The core of the software is composed of intelligent logic judger and intelligent algorithm controller.
The design of the intelligent logic judger is based on the operator's operating experience. According to the input quantity error and the amount of change, the corresponding control strategy is formulated. The principle is:
1) Adjust the amount of material to be fed to the disc feeder according to the noise signal from the ball mill. The amount of material is brought to a stable range.
2) Adjust the air volume baffle and control the two circuits to achieve balance. The intelligent algorithm controller divides the controller into three sub-loops according to the coupling condition of the ball mill system. Each loop adopts an intelligent algorithm, and selects the corresponding algorithm according to the change of its input to achieve the purpose of human-like control.
B. Hardware structure of the control system:
The hardware of the control system is composed of .PLC, Renji computer, isolation and converter, frequency converter, noise and conversion device, flow meter, electric flapper valve, electric butterfly valve, negative pressure transmitter and other equipment. The newly constructed control system can comprehensively detect the key parameters of the milling process, and provide sufficient information to the PIC and the computer through the detection of these parameters, so that the control system can perform comprehensive processing and give accurate control signals to enable the milling system to Work according to the pre-control requirements.
3.2.3 Control system control principle:
3.2.3.1 Quantitative blanking control of ball mill:
According to the actual load of the ball mill, the self-control should compare the given amount set by the operator with the PLC, and change the rotation speed of the disc feeder through the inverter to stabilize the feeding amount around the given amount, and finally make the mill work stable. The requirements for the quality of the mill are up to standard.
3.2.3.2 Ball mill air volume control:
The automatic control of the air volume of the ball mill is based on the air volume of the dust collector, the cyclone separator, the air blower, the particle size of the ball mill, and the size of the material to be discharged. According to the setting value of the grinding mill particle size and the amount of blanking, the PLC controls the speed of the blower through the frequency converter, and controls the dust collector air volume baffle and the ball mill population air volume baffle to solve the ball mill wind, the milling particle size and The dynamic balance of the parameters such as the amount of granules is achieved by self-control.
3.3 Ball mill other technical problems to be explained:
The key to the success of the system is the cyclone separator, the blower, the bag filter, the stability of the air volume of the ball mill, and the basic view of the ball mill. The proportional relationship between the parameters is coordinated to achieve dynamic balance. . Through the actual production, the relationship between the particle size-bag type dust collector air volume, the cyclone separator air volume and the ball mill material level is controlled, and the feeding speed of the ball mill is controlled under a certain air volume. Find the best combination between the level of the ball mill and the ball mill speed and the size of the powder.
4. Ball mill maintenance and overhaul considerations
1. All lubricating oil should be completely discharged when the mill is put into continuous operation for one month, thoroughly cleaned and replaced with new oil. In the future, the oil will be changed every 6 months in conjunction with the medium repair.
2. When the mill is running, the temperature rise of the main bearing lubricant does not exceed 55 °C.
3. When the mill is in normal operation, the temperature rise of the transmission bearing and the reducer does not exceed 55 °C, and the maximum does not exceed 60t.
4. The transmission of large and small gears is stable and there is no abnormal noise. If necessary, adjust the gap in time.
5. The motor current should fluctuate abnormally in days.
6. The connecting fasteners are not loose, and the joint surface has no oil leakage, no water leakage and no leakage.
7. The steel ball is added in time according to the wear condition.
8. The mill liner should be replaced when it is worn 70% or has a crack of 70mm length.
9. When the lining bolt is damaged, the lining should be replaced when it is loose.
10. The main bearing should be replaced when it is severely worn.
11. The tweezers of the lattice ball mill should be replaced when it can no longer be repaired.
12. After the gear surface of the large gear is worn to a certain extent, it can be turned over and used.
13. The pinion gear should be replaced if it is severely worn.
14. When the feed and discharge spirals are worn, they should be repaired in time. If they are too worn, they should be replaced.
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Classification:
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Disadvantages:
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Applications:
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Bouquet: no special taste
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Add antistatic agent to the permanent plate, the volume resistance value of 10 to the 6 to 9 power.
Add flame retardant to the flame retardant board from UL 94v-0 to HB combustion grade, and other modification requirements are required to customize various additional properties according to the actual use of the customer.
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