Superformer Design and Application

The essence of the so-called high-speed super-former is the use of several sets of short long nets in series forming a combination of the Ministry. As far back as the 1960s, Japanese paper machine manufacturers developed a new molding device based on the former. With continuous research and development, the High Speed ​​Ultra Former (High Speed ​​Ultra Former referred to as HSUF) was the most widely used in the 1980s; the speed was up to 350 meters per minute. To date, high-speed superformers have been developed that can reach speeds of up to 600 meters per minute. After 85 years, China has introduced several sets of high-speed superplasticizers from Japan, mainly used for copying kraft linerboard and coated whiteboard paper; two 32OO paper machines at Shanghai Shihong Paper Co., Ltd. and Tianjin Banban Paper Factory. For copying kraft linerboard. Two Taiwanese 2400 paper machines were used in papermaking whiteboard paper in Ningbo Zhonghua Paper and Shandong Huazhong Paper. Recently, Guangdong Liwen Paper Mill introduced a 600-meter high-speed supermolder per minute.
It is well known in the comprehensive institute that the rotary screen forming section has the advantages of low power consumption, convenient multi-layer forming and compounding, and a wide range of adaptability to raw material combinations and varieties of products, but the main disadvantage is that due to the short formation section, it is suitable for The speed is very low (usually below 8M/min), which directly affects the output increase. Followed by the poor quality of forming, the fibers are arranged in the longitudinal direction, resulting in the paper's vertical and horizontal pull ratio is too large. With the increase of the width, the lateral quantitative difference is more difficult to control. In particular, the quality of the noodle layer is poor; it wastes the high-quality raw materials of the noodle and affects the apparent quality of the paper. As early as 1986, we carried out on-site technical surveys of Shanghai Super Solids Paper Co., Ltd. (formerly Shanghai Hongwen Paper Mill) imported from Japan. Through digestion and absorption and analysis, we believe that: An improved shaper designed to address the disadvantages of Parker Molders. It retains the advantages of the series combination of the forming section of the garden net, and draws on the characteristics of long netting and net forming. It uses components such as headboxes, breast rollers, forming panels, dehydration boxes (or case rollers), and vacuum suction boxes. .
Different from the long net device, the forming device is provided with a forming roller, a sheet type net cage, a couch roll, a vacuum trowel, and a suction vacuum box. The short section of the HSUF network is the initial forming section. The length of the forming section is determined according to the process requirements and changes accordingly. The vacuum suction boxes and web cages are vacuum dewatering and pressure dewatering sections. In the vacuum suction box section, there is no obvious waterline like a long web machine, and then the wet pulp with a dryness of 3-4% enters. A net and blankets are compounded and dewatered while being dehydrated and recombined. At this time, the kinetic energy of the dewatering of the wet pulp comes from the original tension of the blanket. We notice that this basis is very similar to the formation of the net, ie the wet pulp is Dehydration will not cause fiber movement due to turbulence. When the wet web enters the web basket section, filtration dewatering is performed. Because, in the dehydration direction of the wet paper web, there is a two-layer filter net. The surface of the web cage is an 8 mesh lining mesh; the outside of the lining mesh is a 60 mesh short length mesh; the dewatering of such a double layer mesh is advantageous for retaining short fibers. When the wet web leaves the web basket section, mechanical dewatering is performed. This is an important process for dewatering and increasing the bond between layers. In this nip, although the applied "line pressure" is not very high, it is generally not more than SKN/cm. However, due to the very low hardness of the roller coated rubber, the contact between the contact roller and the web cage is not in line contact but forms a face contact; this ensures effective dewatering and protects the wet web from Damage, while also maintaining the peelability of the wet web relative to the short web.
The key problem to be solved first in the mechanical dewatering zone is that the wet web after the nip is not wetted. The mechanical dewatering device of the super-former differs from the mechanical dewatering of ordinary presses; it allows the liquid to have a low-pressure flow area in three directions, and the re-wetting is mainly the flow of water squeezed above the couch roller. Therefore, This squat-shaped area is equipped with a quick drainage device - vacuum trowel. The vacuum boring device is equivalent to a vacuum suction box with a suction mouth; the main point of the mechanical design is how to strengthen the sealing; the extrusion water above the roller can be quickly eliminated; because this dehydration zone is the last of a single set of superformers. A dehydration process.
All in all, the web dewatering of the supermolder and the mechanical dewatering under the chip cage are the two important dewatering areas of the former. The forming section of a papermaking machine that uses a superformer generally has a combination of several sets of forming machines. It is mainly based on the quantitative range of the product to configure the number of superplasticizers; the low-quantity multi-layer composite paper for special needs is based on the number of layers required to configure the number of superplasticizers. After multiple sets of super-molders are combined in series, the connotation of dehydration has a qualitative change. In the case of five sets of molding units combined in series, the bottom pulp will pass through five superformers including itself; thus the bottom pulp will obtain five mechanical dewaterings. In the same way, the bottom lining is mechanically dewatered four times, and the core slurry is three times decelerated mechanically. It is easy to understand that this composite method can greatly improve the bond between the layers of the board.
In addition, because the super-former is based on a short-long net, it also has the characteristics of a long net. The slurry is sizing by using a headbox on the Internet. Generally, a step orifice board is used to make the fibers longitudinally and evenly arranged so as to achieve the longitudinal and transverse pull ratio required for paper production. In terms of overall arrangement, the running connection of multiple sets of superformers in series is a forming blanket. Therefore, the wet paper web is always attached to the felt during the forming and dewatering process until it is fed into the press section. The first open area of ​​the wet paper web is after the secondary press. The amount of stretch after fiber interweaving is very small in Russia. To ensure that the physical indicators of paper laid the foundation, which is the advantages of the long paper machine does not have! Another feature of the forming section formed by the combination of the super-shapers is to save power. Taking the example of five sets of series forming units, the net width is 3N0mm, the working speed is m0, and the main equipment power of the forming part is 110KW (the transmission power of each superplastic configuration is 22KW). Molders include the use of mechanical dewatering; this is extremely advantageous for reducing the unit cost of finished paper and enhancing the competitiveness of the product in the market.
The advantages of the HSUF forming department can be summarized as follows:
1. The types of papermaking are various and flexible, and it is convenient to change the varieties.
2, high-speed copying, high productivity.
3. The difficulty of art operation is lower than that of other forming parts; the product rate of paper making is improved.
4, to adapt to the extent of free change.
5, copied out of the paper board physical properties, longitudinal and horizontal pull ratio is small.
6, the combination of layers of the board is good.
7, equipment maintenance and convenient and low cost.
8, power consumption is lower than other forming parts.
There are also some problems in the instance of superplasticizers being put into use. The main problem is that the length of the 8 mesh lining of the web cage is relatively short. The reason is that in the initial design, it is more convenient to consider the thermal shrinkage of the polyester network. In actual use, the stainless steel lining is replaced with a 12-point stainless steel net, and its life cycle is greatly extended.
HSUF is mainly used for the production of coated whiteboard paper; kraft linerboard; corrugated base paper, hanging panel paper, etc. This molding part with oriental characteristics has a wide application prospect in China. At present, China's own design and manufacture of HSUF equipment has been put into use, and the upgraded system of the HSUF system has also entered substantive development and development in digestion.