The role of the powder cleaning machine in the milling process

At present, the competition in the milling industry is becoming increasingly fierce, forcing flour processing enterprises to improve the milling process, in order to produce more and better flour under the same raw grain conditions, which is also an effective way for enterprises to obtain more economic benefits. In the perfect milling process, the correct application of the powder cleaning machine also plays a very important role.

First, the status of the powder machine in the powder road

At present, the domestic milling technology is developing vertically and horizontally on the basis of previous processes, especially in the horizontal development, which plays a more realistic role in grinding high-grade flour. The longitudinal hair extension suit is mainly for improving the powder extraction rate, and the horizontal development is mainly for improving the processing precision of the flour. Generally, the longitudinal length is five skins, eight to ten hearts, two slags and two tails. The horizontal development is mainly through the auxiliary equipment such as powder cleaning machine, grading sieve and pine powder impact machine. The skin, slag and heart powder are fully separated, and the purification is carried out in the product classification and grinding, so as to achieve the purpose of powdering out the powder. The cleaning machine combines the functions of sieving, vibration and airflow to automatically classify the mixture containing slag core powder, fully separate it, and focus on extracting the pure wheat heart to the heart mill to provide good conditions for grinding low-ash flour. It can be said that The powder cleaning machine is the key equipment for the horizontal development and purification of the milling process, reflecting the main role and status of the powder cleaning machine in the milling process.

Second, the correct use of the powder machine

1. Incoming material and attribute of the powder cleaning machine The incoming material of the powder cleaning machine is the skin, slag and heart mixture which are not separated by the anterior dermabrasion sieve, the slag mill sieve, the grading sieve and the anterior core mill sieve. The feed size of the anterior skin mill (1B, 2B) is 18W/36W or 36W/58W, containing skin, slag, carelessness and a small amount of powder. The difference between their capacity and suspension speed is most obvious. Under the appropriate flow rate, the separation and purification are carried out. The effect of clearing powder is most obvious. The slag grinding and middle road grinding (3B) have a similar particle size of 48W/68GG, and the quality is similar. It also contains smaller skin, slag, heart and a small amount of powder. Their bulk density and suspension speed are different from those of the previous road. It is smaller, but still has more obvious separation. The front grading sieve and the anterior core grinding sieve have a feed size of 58 mesh/72 mesh, and the quality is similar, and contains small skin, slag, heart and a small amount of powder. Their difference in bulk density and suspension speed is small, and their powder cleaning effect is worse than the former two.

2. Control of incoming flow and quality of the cleaning machine

First, according to the distribution of the flow rate of each system to the cleaning machine during the process design, the number of the powder cleaning machine is equipped. Secondly, through the operation of the mill and the adjustment of the mesh size of the high-screen sieve, the flow quality of each system to the powder cleaning machine is controlled, so that the materials with similar particle size and ash are entered into the same powder cleaning machine as much as possible. Flow control standard per warehouse: coarse slag 700 ~ 1400kg / h fine slag 300 ~ 700kg / h

3. Equipment and operation of the cleaning machine screen

(1) Screen selection principle: the same layer is dense and dense, and the same section is dense and dense. Due to the action of the ascending airflow, the sieve holes should be significantly larger than the particle size of the specified sieve.

(2) Screen selection method: The aperture of the first stage of the lower layer is the average of the aperture of the all-pass screen of the timing material and the aperture of the retained screen. The fourth section of the screen number is the material full screen number, and the middle two sections are evenly distributed according to the difference between the two sections before and after the screen. If the difference is small, the same screen number can be used for the adjacent two sections. Going to the upper level, the principle is thinner on the 2nd.

(3) The above is the design and theoretical equipment. In the actual production debugging, it should be adjusted according to the soft and hard proportion of the raw materials, the particle size of the incoming materials, and the water level. When the scattering is good, the mesh can be slightly encrypted, and vice versa. The small-grain particles are sensitive and delicate, and the change in mesh size should not be too large, as close as possible. In short, the final result should be adjusted to the correct fit of the airflow. From front to back, the number of sieves in each section should be reduced evenly, and the quality of the sieves should be more and more secondary; . The quality is getting worse. The quality of the underlying screen is slightly better than that of the upper screen. Each section of material can press the corresponding airflow on the screen surface, and no obvious air leakage section can occur.

(4) To achieve the above cleaning effect, not only must there be reasonable screen equipment, reasonable material flow, but also reasonable airflow operation. The cleaning machine has two air volume operation adjustment positions in each warehouse, one is the warehouse top total damper, and the other is the suction chamber adjusting knob. According to the characteristics of the air inlet form and shape of the suction chamber, the adjustment knob is adjusted from the feeding to the discharging direction according to three parts of different sizes. The feed section is enlarged and smaller, the middle section is smaller, the outlet section is smaller and smaller, and the total damper is gradually opened until the sieve material is slightly boiling, and the bran flakes are floated and sucked out to the optimum state. Adjust the wind adjustment knob back and forth so that the material on the entire sieve surface is slightly boiling from front to back, and the state is uniform.

(5) According to the quality and flow rate of the undersize material, adjust the lower bucket to be sent to each grinding port reasonably.

(6) Installation and debugging points: Ensure that the screen surface is horizontal and all cleaning brushes can clean the screen surface back and forth. The above is a summary of the experience after installing and debugging my flour mill, for the reference of colleagues. In short, the effectiveness of the cleaning machine is determined by many factors. Only by fully recognizing the importance of the powder cleaning machine in the milling process, and seriously solving the problems in each link, and repeatedly adjusting, can fully play the powder. The important role of the machine.