CS259298B1 - The method of drying the passport of paper, cardboard and cardboard - Google Patents

Abstract

The solution falls into the field of paper, cardboard and board (PCB) production on paper machines. It reduces heat consumption and intensifies the drying process of the PCB strip by using a cooled cylindrical surface, located on the opposite side of the dried material from the heated dried material strip. On the surface of the cooled surface, condensation of evaporated water vapor occurs and the released droplets adhere. The condensed water vapor and droplets are led away from the dried material on the cooled surface and are removed from it. The solution can be used in the drying of paper, cardboard and board.

Description

259298

SUMMARY OF THE INVENTION The present invention provides a method for drying a paper, cardboard, and paperboard paste in which water is desirable from the dried material, particularly in the papermaking process, in the papermaking process. -renskom machine.

The prior art in the drying of paper and paperboard in their wet process on a paper machine is carried out in a number of ways, which are often combined with one another. The basic method remains the heating of the strip of dried material successively from both sides by means of cylindrical surfaces fumed by natechnologically needed temperature, by almost water vapor. In the first stages of the drying process on a papermaking machine, the paper or paperboard is pressed against the rollers by the so-called felt.

Depending on the needs of the dried paper, cardboard or paperboard, the necessary number of heated rollers are used, which have temperature caps. This basic method of drying practically always combines with drying caps with the blowing of the dried material with warm air, in order to intensify the drying process. In addition, other methods such as so-called vacuum drying are used. Drying methods are described in detail in, for example, V. Hnětkovský: Paper Handbook. In this literature, structural solutions and methods of drying a variety of foreign companies are described, such as Voith, Beloit and others.

Said drying methods require a large amount of energy consumption, and consumables such as kraft paper, about 2.5 to 3 tons of steam per tonne of dried paper are envisaged.

In addition, the drying device is investment-intensive and is minimized in weight. 60% of the total weight of the paper machine.

The aforementioned drawbacks are eliminated by the drying method according to the invention, the principle of which is that the dried web is first heated to one temperature by the desired process and cooled to a temperature of 30 ° C, the condensed vapor and water droplet after heating the other side. they drain off the dried flat material to the dried flat material.

By utilizing the cooled surface, the vaporizing force is increased by the increased vapor pressure difference between the two sides of the dried web. The boundary layer that resists evaporation of water from the surface is reduced. Furthermore, the design of the cooling rollers is simplified compared to the current steam heated roll design, the need for complicated additional hot air blowers and the like is partially eliminated. It is possible to carry out the drying process at lower enthalpy of water and water vapor, thereby saving heat. Further heat savings are the reduction of the overall size of the heated surfaces and thus the reduction of heat loss by radiation and convection heat convection. Drying processes are likely to be extended by the micro-distillation drying process, which means great heat savings.

In the accompanying drawing, three examples of embodiments of the method of drying the tape-like materials according to the invention are shown, wherein FIG. 1 is a system for short-term contact of a cooled material with a cooled roll at its passage between the heated roll VI and the cooled roll V2. The roller V3 serves to introduce the stripped material onto the roll VI and allows it to vary the size of its wrapping with the dried material. Fig. 2 shows a drying system in which the heated dried material contacts the flatter cooling roller. Figure 3 is an example of a drying arrangement for a web of paper, cardboard and paperboard, using a web of paper, paperboard or board to be pressed by felt. Rollers V4 serve to introduce felt on rolls VI and V2. EXAMPLE Three embodiments are illustrated in the accompanying drawings, which may be realized by drying paper, cardboard or paper machine. In each embodiment, at least two cylindrical surfaces (V1 and V2j rollers, of which V1 is fumed, to heat the stripped material, and V2 to be cooled with water, are shown in FIG. 1). between the rolls VI and V2 and the condensation of the evaporated water to the cooling flat cylinder V2 occurs at the point of contact. A water layer is adhered to the surface of the dried web of the material in contact with the cooled surface. 2, the difference is that both cylinders may not be in contact with the strip of dried material, but the basic difference is that the dried strip is in contact with the cooled cylinder surface V2 In the embodiment of the invention shown in Fig. 3, the embodiment is bonded to the use of felt for pressing a web of paper, paperboard, fumigated pouch VI, possibly cooled. The process of the present invention requires the removal of clumping water on the cooled surfaces of the cylinder V2.

It is to be noted that all the three types of embodiments are the basic elements of the PKL drying system in the drying machine and the individual sections of the drying section are constructed, the entire drying section being able to contain a plurality of sections. If there is any other type of cylinder uptake than is currently the case, the use of the proposed

Claims (1)

259298 5 6 reindeer drying forming of sciences. It is not a condition for individual sections to be left out of the elements of a single element. Other types of basic transformations are shown in Figures 4 to 8 for the individual homogeneous sections. We are able to convert the fumigated and cooled chilled rollers to alternate, and in this section, the hot strip is heated on the fumed rollers from one side of the strip and the other side of the chill. Do not touch the cooling surfaces! fumigated metal sheets as well as diameters of V1 and V2 may differ from each other. Fig. 5 shows the basic conversion of Fig. 4, in which a cooling roller V2 is provided downstream of several (2a more) fumed rolls VI. FIGS. 6a) and 6b) show a basic embodiment by rotating the fumed rolls VIa and the cooling cylinder V2, and the dried PKL strip pressed by the cooled cylinder on either side of the smoked roll (FIG. 5a) ), or unilateral (Fig. 5b). The linear pressure size should be adjustable. Just like in the conversion. 4, some of the cooling rollers V2 can be omitted, as well as the diameters of the rollers VI and V2s can differ from each other. FIG. No. 7a) discloses a basic embodiment in which a portion of the fumed roll VI, which has the required larger diameter, is used to heat the PKL belt under the pressure of the plunger. Roller cylinder knows. it is used for the straightening of a dried web with multiple cooling rollers V2 of smaller diameter than V1. FIG. No. 7b) discloses a basic embodiment in which the dried PKL strip on the fumed roll VI is of larger diameter and is the second side in direct contact successively with multiple cooling rollers V2 without using the felt to press the PKL belt onto the roll VI. FIG. 8 shows a basic embodiment of the PKL belt heating without the use of a press felt, whereby, as in the embodiment of FIG. 7b), the individual cooling rollers V2 essentially retain this function. The difference is that the fumed rollers VI have the dimensions of the current drying rollers and the cooled rollers V2, thus allowing a smaller number to be pressed against the fumed roll. The basic embodiment mentioned above can be extended in most practical embodiments by elements which do not relate to the present invention. These elements are, in particular: - controllable wrapping of the cooled rollers by a PKL strip, which is schematically shown in Fig. 9a, by means of a roll V5 which is movable around the roll V2. - Controllable pressing of the PKL-dried strip on cylinder V2 by means of a roller V8 (both fumigated and non-heated), as shown in Figure 9b). If, in view of the quality of the PKL sheet, it is necessary to prevent permanent one-sided drying over PKL thickness, it is believed that in some drying sections or at least in the last drying section, the cooked and cooled areas (sides) of the PKL dried belt, such as schematically shown in Fig. 10, the principle of the desired solution being retained. For the practical application of the invention according to the invention, this drying method can also be used to dry cellulose and felt. The importance of the drying process is to increase the drying intensity, in particular to save heat and to reduce investment costs, both in the reconstruction of existing paper machines and in the construction of new paper machines. According to the results of laboratory tests, it is possible to use a new method with the success especially in the production and drying of acartone paper on flat and wavy layers of corrugated board. Limited use is made of low basis weight, high moisture and low porous paper. SUBJECT MATERIALS A method of drying a web of paper or paperboard, characterized in that the dried web is heated from one side to the temperature required by the ynAlez process and the temperature is lowered to below 30 ° C on the other side, the condensed vapor and water droplets are led to cool flat material outside the dried material. 6 sheets drawing