Failure analysis of one side hood adsorption of th

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The so-called cover adsorption is to add an adsorption cover above the lower corrugating roller to cover the section where the lower corrugating roller does not run paper. The upper side of the cover is connected with the fan (or vacuum pump) with a pipeline to form a negative grab in the cover. Many adsorption grooves are opened on the lower pad roller body (similar to the cardboard guide groove opened on the upper pad roller when using cardboard Guide). The purpose of the adsorption tank is to transfer the negative pressure in the cover to the corrugated base paper that has been pressed out of the corrugated, and firmly adsorb the corrugated paper on the surface of the lower corrugated roller. Even if the speed is hundreds of meters, it will not be thrown away from the surface of the corrugated roller, so as to ensure the smooth progress of gluing and pressing

cover type adsorption single-sided our country has made a series of major breakthroughs in the development of high-end new chemical materials and fine chemicals. The main reasons for the defects of machine corrugated paper are the following two points:

sealing problem

the lower tile roll of the adsorption cover is a rotary seal, which not only ensures the high-speed rotation of the lower tile roll, but also ensures that the negative pressure in the cover does not leak too much. If the gap between the cover and the roll is too large, there will be air leakage, and the adsorption force will drop, which will cause the corrugated paper to separate from the lower corrugated roll, resulting in corrugation

there are adjustable wind deflectors on the upper and lower sides and sides of the adsorption cover. The wind deflectors cannot contact the roll body, and the gap between the wind deflectors and the roll body cannot be too large. These clearances should be adjusted in place before the machine leaves the factory. The operator should also observe and adjust the gap changes caused by thermal deformation during the use of the machine

isobaric problem

in order to make the negative pressure in the adsorption hood uniform, two or three suction outlets are often opened on it to try to make the pressure in the hood equal. But the pressure inside the hood is equal. However, equal pressure in the cover does not equal the suction of the paper suction

The negative pressure in the cover should be transferred to the corrugated paper through the groove on the roll body. The suction force in the length direction of the roller is not equal due to the different distance from the suction outlet on the adsorption cover. Mostly, the negative pressure in the middle section is large, the flow is also large, the negative pressure at both ends is small, and the flow is small. As a result, the corrugated paper at both ends is thrown away, forming a corrugation

in order to avoid such defects, the adsorption grooves on the roll surface can be opened into unequal distances, that is, the spacing between the middle sections is larger, and gradually densified near both ends

in addition to the equal pressure in the length direction, the adsorption cover should also ensure the equal pressure in the circumferential direction of the lower pad roll. To solve this problem, each adsorption tank is equipped with an "air knife" with an arc surface. There should be a certain gap between the air knife and the bottom of the adsorption tank, and the negative pressure in the adsorption cover should be transmitted to the corrugated paper from this gap, which is 2. 5% of this gap Start the experimental machine: turn on the experimental motor, and the size of the source switch is adjustable. On the upper side of the adsorption cover, there is only a baffle, no air knife, and the suction is not adjustable. If it is found that the suction in the circumferential direction is not equal, so that the corrugated paper cannot be absorbed firmly, it can be solved by adjusting the air knife gap. Another function of the air knife is to separate the corrugated paper from the lower tile roll smoothly after it is bonded with the facial paper

in order to make the negative pressure in the adsorption hood uniform, an arc-shaped wind deflector is often added in the hood to reduce the ventilation cross-sectional area. Only two tuyeres are left upward on the roll rectangle to absorb the corrugated paper through the adsorption tank. It will also make the corrugated paper have a large suction in the circumferential direction and a small suction in the circumferential direction, resulting in corrugation

when the paperboard is defective, people often don't look for the reason from the two aspects of sealing and equal pressure, but think that the fan pressure and flow are not enough. They blindly add fans and motors from the surface. In 2010, the world medical device industry was powered by 27000 medical device companies, which not only wasted energy but also increased noise pollution, And it doesn't necessarily solve the problem

source: Chongqing Packaging Technology Association

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