The ability of the Yonker hood to dry the paper sheet is affirmed. in order to better improve the drying capacity and drying speed of the paper machine, the paper machine needs to be equipped with a more efficient air hood-high temperature Yonker hood. This kind of air cover is mainly made of thermal insulation material to prevent its own temperature from spreading to the outside, better ensure dryness, and improve the quality of the paper.
The quality of toilet paper can be improved in the following aspects:
1.) adding short fiber, coating and chemical toilet paper to the original pulp has good softness;
2) in the press part of the paper machine, lower pressure load and lower inlet dryness are used to improve the loose thickness of toilet paper;
3.) the sanitary paper sheet dries less on the Yonker dryer and more on the Yonker gas hood, and the softness and loose thickness of the paper sheet are further improved.
What is the reason for the improvement of toilet paper?
In the production operation, the high-speed and high-temperature Yanke hood sprays high-temperature air on the surface of the paper to dry, which is a problem that moisture transfers heat and quality in an extremely complex form.When the wet paper is introduced into the pressing area, the drying operation occurs at the moment when the paper is in contact with the cylinder, and then the paper is affixed to the surface of the cylinder, and the heat transfer between them dominates the drying process.
When the moisture in the paper turns into water vapor, it flows from the closed space of the wet paper to its surface, migrates out in the form of liquid, fills all the gaps, and then spreads out to the external environment.
When the paper is dry, the evaporation rate of water is at a constant stage, and its surface is always in a wet state, at this time, only in the fiber cover / exposure, the air in other places can not enter the paper structure. Under the joint action of the fiber capillary force and the surface tension of the moisture itself, the moisture in the paper sheet is led close to the surface of the drying cylinder, and the micro-gap on the cylinder surface is filled with evaporated water. At this time, if only relying on the heat energy released by the steam inside the drying cylinder, drying the paper without the hot air cover to strengthen it, the moisture on the open surface of the paper is still subject to fiber capillary force and water stress. Pull back to the closed space near the side of the paper sheet on the surface of the drying cylinder, causing the pulp fibers to accumulate tightly and low on the surface of the cylinder, resulting in a dry sheet of paper.
In the process of paper drying, if a new high-temperature Yonker hood is used to work the paper sheet together, the wet paper transfer heat energy in the drying cylinder body and the high-temperature Yonker hood by means of conduction and convection respectively, that is, the drying rate is accelerated, at the same time, the fiber structure of the paper sheet is improved, and a good effect is achieved. The water evaporation rate of the open surface of the paper is fast, which urges the water vapor in the internal semi-enclosed space to migrate to the open surface. The high temperature air spray on the open surface of the paper can easily occupy the space near it and keep it open. The moisture of the paper existing in the enclosed space is changed into water vapor due to the heating of the surface of the dryer, which is easy to migrate outward to the open surface. At this time, the moisture / water vapor existing in the closed space of the paper, in the drying process, migrates to two heat sources at the same time, so that the structure of the paper has a good open performance.
Increase the temperature of the air in the hot air dryer cover, reduce the internal steam pressure of the Yonker dryer, and the loose thickness of the paper increases by about 1% when the hot air temperature of the hood is increased by 10 ℃ and the steam pressure of the dryer is reduced by 0.5 Pa.
Nowadays, for many large paper machines, the requirement for drying is also increasing day by day. With the continuous improvement of the quality of life, the demand for the quality of paper is also getting higher and higher. The high temperature Yonker hood and Yonker drying produced by our Yonker hood factory work together in the whole drying process. Better results can be achieved in a shorter time.