1、 Process conditions for rice husks:
The process of grain dehulling generally involves three fundamental steps: kneading, kneading, and peeling. Among them, kneading is the key to dehulling, and the size of kneading depends on two important factors: firstly, the size of frictional force, which in turn depends on the pressure between the two rollers; The second is the length of the relative action time of this reverse friction force on the grain, which depends on the relative speed of the two rollers, i.e. the linear speed difference. It is not difficult to see that the pressure and linear speed difference between rollers are important process parameters for rice hulling. The correct selection of them not only directly affects the hulling rate, but also affects the consumption of rubber rollers.
2、 General criteria for selecting process parameters:
The amount of rice milled by rubber rollers is actually an inductive reflection of the shelling rate and glue consumption, which both interact and constrain each other. The optimal process condition refers to both a high shelling rate and a low glue consumption, which is the overall criterion for selecting various process parameters.
1. Selection of linear speed difference: If the linear speed difference is too large, it can enhance the rubbing and tearing force, improve the shelling rate, but also increase the wear and power consumption of the rubber roller. The difference in linear speed is too small, resulting in low dehulling rate, low dehulling consumption, increased return to rice husking, and low total rice milling volume. Therefore, it is necessary to consider both dehulling rate and rubber consumption when selecting linear speed difference. It is wrong to pursue any one indicator unilaterally. Based on our company's years of experience, it is best to choose a line speed difference of 243 meters per second. When the line speed difference is less than two meters, the shelling rate significantly decreases (the fast roller speed of the rice huller is 1350 revolutions per minute, and the slow roller speed is 1150 revolutions per minute; the speed ratio is 1:1.17). The rubber roller of the rice huller is constantly worn during operation, and the line speed difference is constantly shrinking, especially the fast roller. To ensure a certain process effect, it is necessary to maintain a certain line speed difference, When the diameter of the fast roller is smaller than the diameter of the slow roller, replace the fast roller immediately. Generally, the diameter of the fast roller should be larger than that of the slow roller, with a diameter of 2-10mm. In practical operations, the selection of linear speed difference is based on various factors, such as the type of rice, the thinning of the husk, the compactness, moisture content, and climatic conditions.
2. Selection of pressure between rolls: The pressure between rolls is also one of the key process parameters for the large and small amount of tearing force. In the pressure roller rice husker, the pressure between rolls is adjusted by the weight of the roller, which is easy to light but not heavy, balanced on both sides, and can be appropriately increased as the rubber roller gradually wears out; For manually tightened rice huskers, it is appropriate to keep the spacing width between the rolls flat based on the thickness of the rice grains, generally taking 0.5 (indica rice) and 0.8 (japonica rice) mm. The principle of frequent tightening, less feeding, and parallel feeding should be adhered to.
3、 Methods for improving the service life of the grain knee roller and precautions during chain use:
1. Reasonable selection of rubber rollers: For black, brown, white, with a Shore hardness of 90. and 95 °, reasonable selection should be made based on the type of rice, climate conditions, seasons, and other detailed conditions in the local area. It is best to choose a faster roller with higher hardness and a slower roller with lower hardness, avoiding using a single type of rubber roller.
2. Operating temperature control: The actual operating hardness of the rubber roller during rice milling is 82.86 Shore, which is more suitable. According to the measurement, it is advisable to operate at a temperature below 50 ℃ (when the operating temperature is above 60 ℃, the hardness of the rubber roller decreases by 4-8 degrees).
3. Implementing the replacement of rubber rollers: This method can effectively improve the service life of rubber rollers and the amount of rice milled. Its advantage is that each rubber roller has a working interval, which is conducive to eliminating fatigue stress, restoring the function of the rubber material, facilitating the use of different diameters to adjust the line speed difference, and effectively controlling the operating temperature.
4. Strengthen the storage of rubber rollers: do a good job in anti-aging operations. The effective storage period of the rubber roller is set at one year, and it is necessary to purchase appropriate reserves according to the plan, carefully carry out storage operations, and the detailed storage requirements are as follows:
(1) Direct sunlight and rain and snow erosion should be avoided, and the interval between heating devices should not be less than 15 meters.
(2) Prevent contact with substances such as acids, alkalis, salts, oils, and organic solvents that affect the quality of rubber, and maintain cleanliness.
(3) The temperature of the storage warehouse should be maintained between 10-300 ° C and the relative temperature should be between 50 ° C and 80 ° C.
(4) It should rotate vertically and should not be placed horizontally or piled up with other substances. Do not strike to avoid deformation and damage.
4、 The normal phenomenon and reasons for the occurrence of berries during the use of the armpit roller:
1. Rubber rolling produces large and thin heads:
Reason: 1. Uneven weight of the two ends of the compaction; 2. Improper adjustment of rolling distance;
3. Uneven flow rate of rice or skewed dissipation plate; 4. The axes of the two rollers are not parallel.
2. Insert convex or concave in the middle of the rubber roller:
Reason: 1. Flow layer convergence or unevenness; 2. Uneven elimination plate;
3. Worn or crescent shaped gate; 4. The rubber roller has a large and thin end, only pay attention to the tight end;
3. Deterioration on the surface of the rubber roller:
Reason: 1. Jinggu contains hard impurities; 2. The difference in linear speed is too large,
3. The husker caused a serious stir; 4. When the moisture content of rice is too high or the dehulling rate is low, only pay attention to adjusting the roller pitch without paying attention to adjusting the linear speed difference.
4. The operating temperature of the rubber roller is too high:
Reason: 1. Poor ventilation; 2. The line speed difference is too large, the rolling pressure is too high, and the rolling distance is too small;
3. The roughness of the hulled rice is too high; 4. Two rollers touch directly.
5. The outer surface of the rubber roller has vertical and horizontal cross lines:
Reason: 1. Poor drainage of rice; 2. Improper selection of wire speed difference or rolling distance;
3. Loose rubber roller; 4. Static balance prohibition.
6. Excessive wear of rubber rollers:
Reason: 1. The difference in linear speed between the two rollers is too large, resulting in a high shelling rate; 2. Excessive pressure between rolls and tight rolling distance;
3. Rice contains excessive impurities and moisture; 4. The operating temperature of the rubber roller is too high;
5. The hardness of the rubber roller is too high.
7. Rubber roller deformation:
Reason: 1. Improper placement during storage, local aging or melting; 2. Static balance proofreading is prohibited, and the counterweight position is incorrect;
3. The operating temperature of the rubber roller is too high; 4. When it is difficult to shell rice, the continuous operation time is too long.
8. Foaming and peeling of rubber rollers:
Reason: 1. Poor quality of rubber rollers; 2. Rubber roller aging;
3. The direct friction time between the two rollers is too long:
9. Rubber roller detachment, burst, and cavity collapse:
Reason: 1. Poor quality of rubber rollers; 2. The storage time is too long.
10. Rubber roller edge raising:
Reason: 1. The length of the rubber roller itself is incorrect; 2. The length of the two roller device is not aligned.