Vacuum Pump in Paper Industry
Everyone is familiar with and unfamiliar with the paper industry. Familiar with this industry is to guide the use of vacuum pumps. What is unfamiliar is that we do not know which paper mills can use what type of vacuum pumps.
II. Introduction of Technology
Paper application in society is mainly divided into domestic paper and industrial paper. Domestic paper mainly refers to toilet paper. Industrial paper mainly refers to corrugated paper, kraft paper and so on.
The domestic high-grade toilet paper machine is mainly imported from abroad. According to the difference of forming methods, there are mainly two types: crescent type and vacuum circular net type. The main suppliers of crescent toilet paper machine are: Andritz of Austria, Mei Tables of Finland, Jinglong of South Korea of Arceli of Italy, using manufacturers such as Heng'an, APP Jinyehong, Gui Sugar, Yongfengyu, Vida, Jinbaili, Qianli, Prince Nifei, Meijie, Zhongshun, etc. The main suppliers of vacuum circular net toilet paper machine are Kawakawa River of Japan, using manufacturers such as Weida, Zhongshun, Dongguan, Zhongshun, etc. Nanning Phoenix, Jiangmen Renke, Shandong Zhongshun, Dongguan Yongzhao, Weifang Henglian, etc. Its advantages and disadvantages are as follows:
The most outstanding advantages of crescent toilet paper machine are high speed, large capacity and good paper quality. It is generally suitable for large toilet paper mills. Judging from the quality indexes such as softness and loose thickness of products, the crescent-shaped toilet paper machine, especially the model with double-layer headbox structure, has advantages over the BF paper machine, and is more suitable for producing high-grade tissue paper. However, because of its high speed, the ability of the dry and restless parts behind it is required to use hot air hood (gas or fuel oil), which consumes more energy, and also because of a single machine. The capacity of paper machine is large, and it is not as flexible as BF toilet paper machine in variety change. After the new paper machine is put into production, the pressure of product marketing is also great, especially the logistics cost of domestic paper products is high, which is not suitable for long-distance transportation.
Paper machines for industrial paper use different types of paper and different types of machines. However, due to the large output of industrial paper, the speed required is higher.
III. Use of Vacuum Pumps
In papermaking machine, there are many processes using vacuum pump. The most common processes using our equipment are the forming part and the pressing part. The vacuum system of the forming part is set up for dehydration and moulding of paper sheet, and the vacuum system of the pressing part provides a vacuum environment for vacuum suction rollers and vacuum press rollers for sheet transfer, as well as for washing and dehydration transfer of wool cloth. The vacuum degree of the vacuum system of the pressing part is higher than that of the moulding part.
After the air and water mixture from the vacuum system of paper machine passes through the front air-water separator, most of the water is discharged from the lower part of the air-water separator. The air containing a small amount of water is discharged to the back air-water separator through the vacuum pump, and then separated by the back air-water separator. The liquid water is discharged into the collection tank, and the air is discharged into the atmosphere. In practical use, the vacuum system of the forming part and the pressing part generally share a vacuum pump.
Which paper machines can be used for Roots vacuum pumps and which paper machines can be used for water ring vacuum pumps?
When the speed of paper-making locomotive exceeds 1000m/min, water-ring vacuum pump is needed; when the speed of paper-making locomotive is less than 1000m/min, Roots vacuum pump is more used. In the above introduction, the crescent papermaking machine for toilet paper production and the papermaking machine for industrial paper have a speed of more than 1000 m/min, which requires more liquid water to be pumped out in a unit time. This requires a higher vacuum. Generally, the vacuum is above - 60KPa, so most of them use liquid ring vacuum pump; while the speed of circular net BF papermaking machine is about 1000 m/min, and it is taking off. In the water process, the vacuum required is low, generally below - 40KPa, so most of the roots vacuum pumps are used. Round-mesh BF papermaking machine is developed and manufactured by Kawakawa River Paper Machine Co., Ltd. of Japan. Our country has imported it since 1980s. The vacuum pumps used are all wet roots vacuum pumps equipped by Ito Company of Japan, so there are more than 100 sets of Roots vacuum pumps in China. More than 100 Roots vacuum pumps are running on BF paper machines, which need to be replaced.
In the selection of Roots vacuum pump, we must choose wet vacuum pump, do not configure imported muffler and sealing water nozzle, can not use air-cooled tank, as far as possible to reduce the field piping. At low vacuum, recommend Roots wet vacuum pump to users as far as possible. Compared with liquid ring vacuum pump, Roots wet vacuum pump has low energy consumption, stable operation and long service life.