A few key points about paper machines

The paper machine is the main equipment in the papermaking process.To play well with the paper machine,it is essential to be familiar with the various parts of the paper machine.Today,the editor of Xi'an Weiya Paper Machinery Co.,Ltd.briefly summarized the simple functions of each part of a long mesh paper machine for beginners or newcomers to the papermaking industry who are preparing to use the paper machine

The headbox,also known as the front box,is a crucial part of a paper machine

The function of the headbox is to flow the paper material sent by the upper slurry pump from the pipeline into a uniform,rectangular slurry flow with a width equal to that of the paper machine,and its longitudinal flow rate is uniform and consistent

The evenness and uniformity of paper depend on the uniform distribution of fibers and fillers,and the design and operation of a flow box system is very important for a good papermaking system

The main function of the paper machine mesh is to shape wet paper sheets.The slurry with a concentration of 0.4~1.0%sprayed from the headbox weir plate is gradually dehydrated during operation to form wet paper sheets with a dryness of around 16~20%,and then sent to the pressing section

The performance of the web part,along with the headbox,is an important part in determining the quality of the paper page,and the web part has a significant impact on the loss of fibers and fillers

Therefore,a reasonable mesh structure is crucial for improving paper performance and reducing fiber and filler loss

Although a large amount of moisture has been removed from the wet paper sheet at the web,the paper sheet that comes out from the roller generally still has about 80%moisture

If a wet paper with such a high moisture content is sent to the drying section for drying,on the one hand,due to the poor strength of the wet paper,it is prone to breakage,and on the other hand,it relies solely on evaporation drying,which not only consumes a large amount of steam,but also produces paper that is not compact enough,with a rough surface and low strength

Therefore,it is necessary to further dehydrate and improve the dryness of the wet paper by using mechanical extrusion in the pressing section,while increasing the tightness of the wet paper,eliminating mesh marks,improving smoothness,increasing strength,and reducing breathability and permeability

After being pressed and before drying,the dryness of wet paper is generally only 30-40%.Even in new paper machines with composite pressing,the dryness is only 40-50%.Therefore,it is necessary to use a drying cylinder to evaporate water to meet the moisture requirements for paper production

The drying section of a paper machine consists of one or more drying cylinders,with equipment costs and power consumption accounting for more than half of the entire paper machine.Steam consumption accounts for 5-15%of the production cost

So reasonable design and process are of great significance for improving production capacity,ensuring product quality,and reducing production costs

The main function of the drying section in the papermaking process is to heat the wet paper after pressing,allowing it to evaporate excess moisture,thereby meeting the requirements of product quality.At the same time,it improves the strength of the paper,improves some physical properties of the paper,and completes processes such as sizing and dyeing

Generally,the drying section of a paper machine is equipped with a calender.The purpose is to improve the glossiness,smoothness,and tightness of the paper after being calendered,resulting in a paper with uniform thickness

A regular calender generally consists of 3-8 rollers,each in a vertical line and installed on the same frame.The lower roller is the driving roller,and the other rollers are driven by friction

The number of rollers in a calender is generally determined by the vehicle speed and the type of paper used

The paper rolling machine is located at the end of the paper machine and is used to roll the paper web into paper rolls

In paper production,the key is to produce paper with consistent thickness

But if the thickness is slightly different,controlling the coiling can also make up for the paper.The paper rolling machine can be divided into shaft type and cylindrical type according to the winding principle

The purpose of rewinding is to further process the paper roll to meet the needs of other printing lines

The working principle of rewinding is:the paper roll taken from the paper machine is placed on a paper support frame,and the brake on the paper support frame maintains a certain tension on the paper roll.When the paper roll breaks,it quickly brakes.The paper roll is cut into the required width through the longitudinal cutting mechanism of the paper guide roller,and then rolled into a paper roll according to the required tightness diameter

The main structural parameters of the rewinder are the width of the paper web and the speed it can handle,followed by the diameter of the unwinding coil and the transmission method of the paper cutting method

The types of rewinding machines can be divided into:upper paper rewinding machine,lower paper rewinding machine,single roll rewinding machine,specialized rewinding machine,etc