Solution: If the preheating roller of the rotary steamer is used, if the temperature is low or the temperature difference between the two ends is more than 5°C, it indicates that the suction pipe is damaged or the mounting position is incorrect, and it should be opened for maintenance.

The water volume of the water delivery valve is 2 to 3 times that of the condensate. If the water volume is insufficient, the water transfer valve should be replaced.

Check the discharge valve of the water delivery valve every week and clean it if it is blocked.

The quality of the paste, the size of the water, and the thickness have a great influence on the water content of the board.

If the paste has a large amount of water, a thin paste, a fast penetration, the water content of the cardboard is high. Conversely, the water content is small.

The solution is: strictly follow the times and ratio of the paste water and the mixing time to paste, master the viscosity of the paste. The viscosity of a general single-sided machine is 50 to 60 seconds, and that of a double-sided coating machine is about 100 seconds, and the double-sided coating machine should use the fresh paste made on the day. Only the production of good paste can produce qualified cardboard.

The amount of top paste affects the moisture content of the board

When the paste is the largest, the water content of the board is large, and the amount of water on the top of the board is small.

The processing method is as follows: For a single-sided machine, adjust the gap between the rubber roller and the rubber roller, the rubber roller and the main corrugating roller. Under normal circumstances, the gap between the rubber roller and the rubber roller is 0.2 to 0.25 mm, and the gap between the rubber roller and the main corrugating roller is generally 0.1 to 0.2 mm.

The gap between the scraper and the top roller of the double-sided gluing machine is 0.2 to 0.25 mm. The gap between the press roll and the top roll should be 0.05 to 0.1 mm lower than the height of the single-sided corrugated cardboard that is passed. The measurement method is to use a feeler gauge to measure the data at both ends. Whether it is a single-sided machine or a double-sided gluing machine, the width of the corrugated cardboard glue line produced is generally 1.5 to 2 mm.

As the above roller roller surface damage or foreign body caused uneven sizing, affecting the cardboard water content is uneven.

The solution is: if the roller surface is worn or damaged, replace the rubber roller as soon as possible. If there is any foreign matter, it should be stopped immediately. All the rollers need to be cleaned every day after work, and foreign objects should be removed with a soft brush.

If the conveyor belt is poor in breathability, or if water is sprayed onto the conveyor belt, the water content of the board can be large.

The solution is: to analyze the reasons for the poor air permeability of the conveyor belt. If there is waste paper sticking up, it is necessary to immediately stop and remove it. If the large belt is used for a long time, the new belt must be replaced. Do not spray water on the conveyor belt during use.

If there are too many single-sided paperboards on the conveyor belts of the single-sided machines on the flyover, the time will be long and the water will disperse more, which will cause the water content of the board to be less.

The solution is: All operating stations across the board should always contact each other and take care of each other. The speed of operation should generally be unified. The storage capacity of the single machine board on the conveyor belts of each single-sided machine on the flyover can best account for 2/3 or 3/4 of the length of the conveyor belt.

Climate and environment will also have an effect on the moisture content of the board

In the high temperature and rainy season, the relative humidity is high, the flowability of the winter paste is poor, and the amount of upper paste is small, which will affect the moisture content of the cardboard.

The solution is: In the season with high temperature, increase the thermal area, reduce the spray, reduce the moisture content of the paste, increase the temperature, and make full use of the preheat roll to adjust the moisture content.

In short, there are many factors that affect the moisture content of the board, which requires operators to strengthen their sense of responsibility, careful observation, careful adjustment, in order to produce qualified corrugated board.
(author/Kang Xiong)

Information Source <China Packaging News>