The definition of the paper machine industry refers to machinery that includes raw material preparation, pulping, paper making, until finished rolls or flat sheets, and paper and paperboard. For more details, the following is a small paperwork definition and classification of the paper machinery industry.
Paper machine types:
The paper machine has a long net multi-cylinder paper machine, a rotary paper machine, etc., and the types of paper machines used according to different paper products are also different.
Material preparation equipment
It is a equipment for pretreatment and processing of papermaking raw materials before cooking or refining according to the requirements of cooking or refining process, and is divided into non-wood fiber preparation equipment and wood fiber preparation equipment. The former has a lawn mower, a cutting machine and a sugar cane refining machine, and the latter has a peeling machine, a chipper and the like.
The chipper is a machine that cuts the logs needed to produce wood pulp into a certain size of wood chips. It is divided into two types: disc type and drum type. The digester dissolves the lignin in the papermaking material into the cooking liquid to separate the papermaking materials. The equipment for fiber is divided into two types: batch type and continuous type; the wood grinder is a kind of equipment for producing ground wood pulp. It can be divided into two types according to the production mode: batch type and continuous type. Hydraulic pressure type and mechanical pressure type;
It is the equipment used to separate the plant material into fibers. The pulping method can be divided into chemical method, mechanical method and chemical mechanical method, and the corresponding pulping equipment includes a digester, a wood grinder, a hot mill, a washer, a bleacher, a beater and a waste liquid recovery device.
After the wood chips are preheated by steam, the slurry which is ground in the high pressure state is called hot wood chip ground wood pulp. The machine for making hot wood chips ground wood pulp is a heat mill. The heat mill consumes a large amount of electricity, so it is sufficient. The use of heat energy in the refining process is a key issue in the hot mill; the washer is a mechanical device that separates the cooked pulp from the black liquor. According to the black liquor extraction rate, there are two categories of high concentration and low concentration extraction.
The purpose of pulp bleaching is to remove the residual lignin and pigment in the slurry after cooking, to improve the whiteness of the slurry, and to make the pulp have a white color. The bleaching machine is a bleaching device commonly used, which is composed of a bleaching tank auger, a washing drum and the like. The slurry and bleach are placed in the tank and the washing water is continuously added, and the flow is circulated in the pool by the action of the auger to complete the mixing and chemical reaction process. The water with bleaching product and residual bleach is discharged through the drum cavity to the white pulp.
It is a complete set of equipment for making the pulp form a part of the paper web, including the headbox, the net part, the press part, the drying part, the calender, the reel, and the main part of the transmission part, and steam, water, vacuum, lubrication. , auxiliary systems such as heat recovery. The net portion forming the wet paper web is the core of the paper machine, so the paper machine can be further divided into a long net paper machine, a net paper machine and a cylinder paper machine according to the structure of the net portion.
The headbox is a device that uniformly and stably delivers the appropriate concentration of slurry to the net through a cloth, a rectifying device, a sump, a stern nozzle, etc., also known as a headbox; the slurry is sprayed from the headbox to the copper. After the net, a wet paper sheet is formed on the net portion and dehydrated; followed by pressing, that is, mechanically extruding the moisture of the wet paper sheet coming out of the net portion, improving the dryness of the paper sheet, and improving the surface properties of the paper sheet. Eliminate the net marks and increase the smoothness, tightness and strength; then enter the drying section to further dehydrate the pressed wet paper sheet, shrink the paper, tightly bond the fibers and increase the strength.
After the paper sheet from the drying section is calendered by the calender, the smoothness, gloss and tightness of the sheet can be improved, the thickness of the sheet can be uniform, and the air permeability can be reduced. Finally, the web of the paper machine is used. Rolling into a paper roll completes the main process of papermaking. In order to meet the different needs in the future, a supercalender, a winder, a paper cutter and the like are also arranged after the paper machine.
The paper industry consumes large amounts of raw materials, water, electricity, and chemicals, and produces large amounts of wastewater and waste. Therefore, the future of papermaking machinery will be developed to use a wide range of papermaking materials, reduce materials and energy consumption in the papermaking process, and reduce environmental pollution. For more information on the paper machinery industry, please refer to the “2015-2020 China Paper Machinery Industry Development Forecast Report” published by the China Report Hall.