Will be in line with the paper requirements of the pulp water suspension by the screen dehydration forming, mechanical extrusion dehydration and drying process and copied into paper machine. The papermaking machine includes three main parts of the forming, pressing and drying of the above process, and equipped with the necessary finishing, coiling and transmission, as well as slurry, slurry and white water circulation, vacuum, ventilation exhaust Paper handling and lubrication, automatic control and other auxiliary systems. The specifications of the paper machine are often expressed in terms of the width of the paper, the width of the copper mesh and the preferred working speed. Modern large paper machine copy width of up to 11m, the working speed of more than 1000m / min, Nissan paper amounted to hundreds of tons, the weight of the whole machinery more than 1,000 tons, up to 100 meters.

According to the needs of the papermaking process, the paper machine structure in various forms, generally by the flow, forming, pressing, drying, finishing, coiling and transmission components and auxiliary systems and other ancillary equipment.

Forming part

From the headbox, chest roll, forming the network, the suction box and the roll and other components. The slurry tanker dispensers the slurry sent by the delivery system evenly to the forming wire, and the pulp speed and the speed should be matched. Control of pulp speed and speed is the main factor in the selection of the headbox box type. The fully enclosed hydraulic headbox is used to adjust the pulp pressure to adjust the pulp pressure, suitable for high-speed paper machine; air-cushion headbox is to adjust the air cushion pressure to speed, and open high-level headbox Then adjust the tank height to adjust the speed, suitable for medium speed paper machine; open compartment headbox is suitable for low-speed paper machine. Forming the network for the endless ring network, between the chest roll and the frontal roller, forming a horizontal or slightly inclined flat mesh surface, as the pulp dehydration work section, used to call it a net case, which is called long network. If the endless forming network placed on a circular cage, the arc of the deformation of the working section, known as the rotary screen. If the drill hole with a steel mesh drum, suction from the shaft end of the vacuum to speed up the forming of the mesh surface of the pulp is called vacuum rotary vacuum or vacuum forming network. If the pulp is in the two long net clamping, the two networks at the same time for dehydration is called the folder forming machine (Figure 2). These formers use different forms of dewatering elements to accelerate the dewatering of the pulp on the web. Components are divided into static, rotating and both. Static components such as dewatering boards, arc vacuum boxes, etc., rotating components such as roller, vacuum forming roll and so on. In addition to the use of a single form of forming a long line of paper machine, round paper machine, folder paper machine, but also with a long net, multi-round net, multi-folder network and a variety of forms of circular rotary forming a combination of forming The

Press the press

The wet sheet after forming is further dewatered in a pressurized manner. It consists of a roll of hard and soft rollers, such as stone roller and roller to form a group of presses. The press section consists of the same or different forms of press packs, which also conventionally include a vacuum suction device. Squeeze, with appropriate specifications of the wool supporting the paper, it can be uniform pressure and take part of the pressure squeezed out of the water, and can increase the pressure of pressure to improve the pressure of the press. Low-speed paper machine using 20 ~ 60kN / m line pressure, high-speed paper machine with up to 210kN / m line pressure, when using high-pressure squeeze, such as wet press machine press up to 350kN / m line pressure; Into the vacuum pressure roller, groove pressure roller, lining pressure roller, blind hole pressure roller, etc., in order to more effectively squeeze the water from the nip, which are since the 1950s to improve the efficiency of the new technology to improve the pressure. And then use the compound press structure to form a closed paper. It is composed of two or three sets of presses, the vacuum paper is peeled from the forming wire by the vacuum suction roller, fed into the composite press with the felt, and then the paper is conveyed between the press rolls, thereby eliminating the past Squeeze between the weight and other factors caused by the traction caused by the phenomenon of decapitation. Since the 1980s, there has been a wide nip press technology, a tough rubber band or a rubber roller, deformed at a strong pressure, and thus has a pressure of up to 750 kN / m and a wide contact surface with a significantly prolonged dewatering time Greatly improving the ability of pressing dehydration, high-speed paper machine on the effect is more prominent. Now squeeze the paper dryness from the past 30 to 37% to 43 to 45%, and some even up to 50%. The number of times the sheet touches the smooth hard roll surface or the number of rough surfaces and the amount of dewatering on each side can affect the surface quality of the sheet. Reasonable processing can significantly reduce the smoothness of the difference between the two sides of the page, and vice versa can also cause differences in the smoothness of the two sides increase.

Drying Department

By a gear drive or by the felting drive a number of dryer for a group, a number of dryers constitute a dryer. The linear velocity of each cylinder can be adjusted separately to maintain the differential speed between the cylinders to compensate for the shrinkage of the sheet during drying. Drying of the paper dryness is generally about 92 ~ 94%. In the end of the dryer, usually with a cold cylinder, so that water can be condensed in the cold cylinder surface. The condensate can wet the surface of the paper to facilitate better surface smoothness in the finish. The diameter of the dryer is preferably 1.5m. Single-sided light paper can be used by high hardness, high degree of clean cylinder large diameter dryer and get a high single-sided gloss, large diameter dryer diameter generally used 3 ~ 7.5m.

Surface finishes

With multiple processes to achieve good surface quality. Most of the paper in the paper machine after a mechanical calendering machine calendering, so that the paper flat. The mechanical calender consists of a number of chilled iron rolls, which are flattened with the weight of the rollers or by pressing. If you need a higher surface smoothness will use super calender pressure. It is usually composed of paper roll and chilled iron roll. Depending on the requirements, some varieties are subject to surface sizing to improve the surface quality; some are subjected to surface coating to improve the appearance quality or print quality. Surface sizing, coating can be used in paper outside the paper machine through the sizing machine and coating machine for processing, can also be sizing machine and coating equipment combined in the machine for machine processing.

Transmission system

The paper machine to connect the various parts of the synchronous operation, so that mechanical electrical integration. By the mechanical slowdown device, speed control speed devices, sub-transmission devices, etc., are used as power source.

White water system

It is a system for the recovery, treatment and reuse of the paper machine forming section. Including white water collection, transportation, filtration or precipitation, air flotation and other equipment to separate the recovery of fiber and filler reuse, and clean white water in the papermaking process of recycling the entire system.

auxiliary system

It is composed of electrical system, vacuum system, lubrication system, workshop exhaust system, paper disposal, compressed air system, steam supply and drainage system and so on.