When in the production of corrugated board, first of all, place the base paper in the size of cylinder on the non-shaftframe, and gradually unrolled under the tension control, the paper web goes into the corrugated machine through preheater, and produce flute to glue with inner linerboard, forming a single-side corrugated board; Secondly, the single-sided cardboard is transported to the gluing machine for applying, and gluing with linerboard, and then sent to the dryer; Finally, cardboard of various of specifications according to the requirements of scoring, longitudinal cutting, crosscut are exported through stacking output and corrugated board production completed.
The preheater is mainly composed of drying cylinder, paper guide roller, angle adjustment roller and steam system (rotary joint, siphon, etc.), electrical control system. In the production process of corrugated board, the role of preheater is to provide heat to the paper web, through preheating paper web, so that the water content of the paper to meet the corresponding requirements, to facilitate corrugated forming, and energy saving.
A preheater is usually heated by saturated steam. The surface temperature of the dryer is generally about 160 degrees (if it is high-speed tile line, the surface temperature of the dryer to achieve 180 degrees), the preheater work mainly by adjusting the paper web on the dryer package angle, in order to change the contact area, to adjust the water contentand temperature of the paper.
If the paper web is not preheated, the following problems may occur:
1.Paper web is too wet. Water will affect the paper fiber absorption adhesive, resulting in the process of paperboard degumming cracking.
2.The paper is too dry. Paper fiber will absorb a lot of water adhesive, adhesivecan not be very good penetration and stay in the paper surface, adhesive partis small and shallow, easy to cause poor adhesion.
3.Uneven water content of paper. One layer of paper moisture is high, while another layer of paper moisture is low, resulting in corrugated board warping.
When purchasing equipment, the following five aspects should be considered for preheater:
1) Angle range (200-270 degrees), the preheater should be able to adjust the maximum angle;
2) What kind of angle control system being used to effectively control paper temperature;
3) What kind of steam control system is adopted to save energy;
4) Whether it is able to control tension;
5) Whether it has the humidification capacity of the preprocessor.