Design and application of the hottest super shaper

2022-09-23
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Design and application of superplasticizer

to build a national aviation material production base and a national military civilian integration innovation demonstration zone, the essence of the so-called high-speed superplasticizer is to use several sets of short and long series forming parts. As early as the 1960s; Japanese paper machine manufacturers have developed a new forming device, super former, on the basis of circular former. With the continuous development and summary in the future, by the 1980s, the most widely used is the high speed ultra former (hsuf for short); The speed can reach 350 meters per minute. So far, it has developed into a high-speed superplasticizer with a speed of up to 600 meters per minute. After 85 years, China has successively introduced several sets of high-speed superplasticizers from Japan, which are mainly used for making kraft liner paper and coated white board paper; Two 32oo paper machines are located in Shanghai Shihong Paper Co., Ltd. and Tianjin Paperboard Factory respectively; It is used to make Kraft linerboard. Two 2400 paper machines are used to make coated white board base paper in Ningbo Zhonghua paper industry and Shandong Huazhong paper industry respectively. Recently, Guangdong Liwen paper mill introduced a high-speed superplasticizer of 600 meters per minute

as we all know, the circular forming part has the advantages of low power consumption, convenient multi-layer forming and compounding, and wide adaptability to the raw material combination and variety of products, but the main disadvantage is that due to the short forming section, its adaptive speed is very low (generally below 8m/min), which directly affects the increase of output. Secondly, the forming quality is poor, and the fibers are arranged longitudinally, resulting in the excessive vertical and horizontal tension ratio of the paper. With the increase of the width, the horizontal quantitative difference is difficult to control, especially the uniformity quality of the noodle layer is poor; It not only wastes the high-quality raw materials of vermicelli, but also affects the apparent quality of paper. As early as 1986, we conducted on-site technical surveying and mapping of the high-speed superplasticizer imported from Japan by Shanghai Shihong Paper Co., Ltd. (the former Shanghai Hongwen paper mill); Through digestion, absorption and analysis, we believe that the high-speed super former is an improved Cheng 9 Useful elasticity and hysteresis loss: it is molded on the steel wire hydraulic universal experimental machine. It retains the advantages of the series combination of the circular forming part, and absorbs the characteristics of long-term papermaking and pinch forming. First, it uses headbox, chest roll, forming plate, dehydration plate box (or table roll), vacuum suction tank and other components

different from the long device, the former is equipped with forming roller, sheet cage, couch roll, vacuum weir knife, suction vacuum box and other devices. The short and long section of hsuf is the initial forming section, and the length of the initial forming section is determined according to the process requirements and changes accordingly. The vacuum suction tank and chip cage are the vacuum dehydration and pressure dehydration sections. There will be no obvious water line like the long paper machine in the vacuum suction tank section, and then the wet pulp with a dryness of 3-4% enters a clamping area with the blanket for compounding, dehydration and dehydration while compounding, At this time, the kinetic energy of wet pulp dehydration comes from the original tension of the blanket. We note that this basic principle is very similar to pinch forming, that is, wet pulp will not move fibers due to chucking during dehydration. When the wet paper sheet enters the chip cage section, filtration dehydration is implemented. Because there are two layers of water filtering in the dehydration direction of the wet paper web. The surface of the chip cage is lined with 8-purpose liners; Outside the lining is 60 mesh short and long; This double-layer filtration dehydration is beneficial to the retention of short fibers. When the wet paper web is separated from the chip cage section; Mechanical dehydration is implemented. This is an important process of collecting dehydration and increasing interlayer adhesion. In this pressing zone, although the applied "line pressure" is not very high, generally not more than SKN/cm. however, due to the low hardness of the rubber covered by the couch roll, the contact between the couch roll and the sheet cage is not line contact, forming a surface contact; In this way, it can not only ensure effective dehydration, but also protect the wet paper from damage, while maintaining the relatively short and long peeling property of the wet paper

the key problem to be solved in the mechanical dewatering area is that the wet paper that passes through the pressing area is not rewetting. The mechanical dewatering device of the super former is different from that of the ordinary press; It enables the liquid to have a low-pressure flow area in three directions, and the main cause of wetting back is the water flow extruded above the couch roll. Therefore, a rapid drainage device - vacuum weir knife is set in this wedge-shaped area. The vacuum weir knife device is equivalent to a vacuum suction tank with wedge-shaped suction port; The key point of mechanical design is how to strengthen its sealing; The extruded water above the couch roll can be quickly discharged; Because this dehydration area is the last dehydration process of a single set of superplasticizer

in a word, the surface dehydration of the super shaper and the mechanical dehydration under the chip box are the two important dehydration areas of the shaper, such as pulling, pressing, bending, shearing, peeling, tearing, piercing, wearing and so on. The forming part of a paper machine with a super former is generally composed of several sets of shapers. It is mainly based on the quantitative range of products as the basis for configuring the number of super formers; For low weight multi-layer composite paper with special needs, the number of layers required is the basis for configuring the number of super formers. After series combination of multiple sets of super formers; The connotation of dehydration has a qualitative change. Taking five sets of forming parts combined in series as an example, the bottom slurry will pass through five super formers including itself; In this way, the bottom slurry can be dewatered by mechanical reduction for five times. In the same way, the bottom lining slurry obtains four times of mechanical reduction composite dehydration, and the core layer slurry obtains three times of mechanical reduction composite dehydration... It is not difficult to understand that this composite method can greatly improve the interlayer bonding of paperboard

in addition, because the superplasticizer is based on short length, it also has the characteristics of long forming. The headbox is used for sizing, and the stepped orifice is generally used for sizing, so that the vertical and horizontal arrangement of fibers tends to be uniform, so as to achieve the vertical and horizontal tension ratio required by the paper. In terms of the general layout, the running link of the series combination of multiple sets of superplasticizers is the formed blanket. Therefore, during the process of forming and dehydration, the wet paper web always runs on the blanket until it is sent to the press. The first opening of the wet paper web is after the second press, and the stretching amount after fiber interweaving is very small, which lays a foundation for ensuring the physical index of paper, which is an advantage that the long paper machine does not have! Another feature of the forming part formed by the series connection of the super formers is to save power. Taking five sets of forming parts combined in series as an example, the net paper width is 3n0 mm, the working speed is M0 h, and the power of the main equipment of the forming part is 110KW (the transmission power configured for each set of super formers is 22KW), which is because the super formers include mechanical dehydration; This is extremely beneficial to reduce the unit cost of finished paper and enhance the competitiveness of products in the market

The advantages of hsuf forming part can be summarized as follows:

1. The varieties of copying are diverse and flexible, and it is convenient to change varieties

2. It can be copied at high speed and has high productivity

3. The difficulty of operation is lower than that of other molding parts; Improve the yield of finished paper

4. The range of adaptive dissociation is large

5. The printed board has excellent physical properties and small vertical and horizontal tension ratio

6. The interlayer bonding of paperboard is good

7. Equipment maintenance is convenient and low cost

8. The power consumption is lower than that of other forming parts

there are also some improvement problems in the example of putting into use. The main reason is that the service cycle of the 8-mesh lining on the surface of the chip cage is relatively short. The reason is that considering the convenience of the polyester heat shrinkable sleeve in the initial design, it is changed to 12 mesh stainless steel lining in actual use, and its service cycle is greatly extended

hsuf is mainly used to produce Coated Whiteboard; Kraft linerboard; Corrugated base paper, hanging panel paper, etc., this molding part with oriental characteristics, has a wide application prospect in China. At present, hsuf equipment designed and manufactured by China has been put into use, and the upgraded system of hsuf system has also entered substantive development and research

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