Top roller embossing hob type top roller embossing machine
After 1996, the China Agricultural Mechanization Research Institute learned from the experience of foreign hob gins and independently developed a domestic hob-type top roller gin, which gradually replaced the punch-knife top roller gin.
The hob-type top roller embossing machine and the punch-type top roller embossing machine are different in structure. It uses a needle roller to replace the conveying loosening roller, an accelerating roller to replace the push plate, a hob to replace the punching knife, and a cotton grid to replace the cotton comb. Structural changes reduce the vibration of the equipment, making the equipment stable, easy to adjust, and more efficient.
(1) Characteristics of hob top roller embossing machine
The main components of hob top roller embossing machine are top rollers, fixed knives and hobs. The surface of the top roller should be rough and elastic. Because the hob-type top roller gin uses the friction between the top rollers on the cotton fibers to exert traction on the cotton fibers, and in the other direction “impacts the cotton with the hob” to exert impact force on the cotton. Under the combined action of friction and impact forces in different directions, the fibers and cotton are separated to complete the ginning work. Since the fibers on the sub-cotton have natural spiral curls, the friction coefficient between the surface of the top roller and the cotton fibers is relatively large. When the cotton fiber contacts the surface of the top roller with a certain pressure, the two will embrace each other and produce friction.
When the friction force on the surface of the top roller against the cotton fibers is large enough, the fibers can run with the surface of the top roller. The fibers on the cotton are entangled with each other, so the cotton fibers can be continuously pulled by the top roller. When the cotton fiber pulled by the top roller reaches the fixed knife edge, it passes through the fixed knife edge with the help of the elasticity of the top roller and the softness of the cotton fiber. Because the fixed knife is close to the surface of the top roller, the cotton is blocked at the fixed knife edge. At this time, the fibers in the fixed blade are straightened and then slide relative to the surface of the top roller. The hob rotates at high speed and continuously impacts the cotton seeds retained at the fixed knife edge. Under the combined action of the movable knife and the fixed knife, the fibers and cotton seeds are separated. The fibers separated from the cotton seeds continue to move forward with the top roller, turn at a certain angle and are sucked away by the airflow, and enter the lint pipe.
From the above principle, it can be seen that increasing the friction between the fixed knife and the surface of the top roller can increase the friction between the surface of the top roller and the fibers, making it easier for the fibers to break away from the cotton. Therefore, if the pressure of the fixed knife on the surface of the top roller is increased, the traction force of the top roller on the cotton fiber will be stronger and the output will be higher.
When the pressure of the fixed knife on the surface of the top roller is too great, the temperature of the surface of the top roller will rise sharply, and the top roller will be easily worn. When the fiber passes through the fixed knife edge, the wax layer on it will be destroyed, and the color of the rolled lint will be dull and dull. , sometimes it is even possible to scrape off the lint and cotton skin on the cotton seeds. If the pressure of the fixed knife edge on the surface of the top roller is too small, the output will decrease, and impurities will easily pass through the fixed knife edge with the lint, causing the lint to contain more impurities and produce more lint heads. Therefore, top roller gin is different from sawtooth gin. The hob top roller gin is easy to produce small flower heads. At the same time, the lint forms flakes after rolling, and the impurities in the cotton are easily pressed into the lint sheets after rolling, making it difficult to clean. In order to solve these problems, the layout of the hob top roller embossing process should be different from the layout of the sawtooth embossing process.
(2) Layout of the hob top roller embossing process
1. Recycling of small flower heads
The design of the hob top roller embossing process must first consider the recycling of small flower heads. Because the hob-type top roller gins currently on the market, whether they are domestic or imported, have in common that they have a lot of small embossing heads (normally about 10%).
If you ignore these little tricks, it will affect the future sorting process and also cause economic losses to the company. In order to solve this problem, a small flower head recovery machine should be configured in the process, so that after the small flower heads are recovered, they can re-enter the cotton distribution auger and enter the top roller gin.
2. Lint cleaning
Traditional sawtooth lint cleaning is to directly enter the loose lint into the sawtooth lint cleaning machine after sawtooth ginning; or first enter the airflow lint cleaning machine, and then enter the sawtooth lint cleaning machine. However, this method is not suitable for cleaning the top roller cotton. Because the top roller cotton is in a sheet shape, the small impurities in the lint are pressed into the lint cotton pieces, making it difficult to clean. The cleaning process of top roller cotton is divided into 3 stages.
(1) The cotton pieces rolled by the hob-type top roller gin are collected into the cotton collecting machine, then enter the long-staple cotton cleaning machine, and then enter the air-flow lint cleaning machine. Since the output of the top roller gin machine is low and there are many small flower heads, multiple units can be used in parallel. Lint cleaning is centralized cleaning, so the flake lint produced by each top roller gin should be merged into the lint collector first. After passing through the lint collector, the lint flakes will be pressed more tightly.
(2) The lint coming out of the cotton collecting machine enters the long-staple cotton cleaning machine. The long-staple cotton cleaning machine does not damage the fiber. The process only uses a roller to gently loosen the sheet lint, and remove the fine powdery impurities and Very small particles are removed.
(3) The loose lint coming out of the long-staple cotton cleaning machine enters the airflow lint cleaning machine. Any large impurities that are difficult to clean can be removed by the airflow lint cleaning machine.
3. Conveying method of cotton seeds
During the conveying process of cotton seeds rolled by the hob-type top roller gin, the inclined auger and station auger should be avoided as much as possible. Because the cotton rolled by the hob-type top roller gin contains about 10% of the florets, these types of augers can easily entangle the cotton fibers on the florets.In the shape of a rope, it is not conducive to the recovery of small flower heads and causes the loss of cotton fibers. Wind suction should be used as much as possible, so that the small flower heads in the cotton will not cause fiber entanglement and loss.
4. Ensure the dryness and cleanness of the compressed gas
Since the key component of the top roller gin machine – the action of the top shaft is controlled by the air circuit, the compressed gas generated from the air compressor must pass through many processes before entering the cylinder. Secondary filtration to ensure the dryness and cleanliness of the gas. Due to the severe cold climate in my country in winter, especially in Xinjiang, the winter temperature is below -20°. The compressed air generated by the air compressor contains water vapor. When it passes through the main pipeline and each branch pipeline, due to the temperature drop of the compressed gas, it will The water vapor in the gas condenses or even freezes, causing the pneumatic components to freeze and cause malfunction or even damage, causing the failure of the entire gas circuit system, thus affecting the normal operation of the equipment in the entire process system and putting the entire process system in a state of paralysis. Dirty compressed air will also cause wear and damage to various pneumatic components, affect the normal operation of the top roller gin machine, and paralyze the entire process system.
At present, a single cotton gin has been added with an automatic flower feeding system, cleaning system, and mechanical, electrical (hydraulic) integrated automatic microcomputer ginning system.
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