The paper sizing and coating machineneeds to do a good job in all aspects of maintenance work, not only to ensure that the equipment is safer during use, but also to reduce the occurrence of failures, and it can also better extend the service life. Today, Jinan easttai editor Share with you the maintenance knowledge of the coating machine: how to do the daily maintenance work, and what are some specific methods?
To do a good job in daily maintenance of paper sizing and coating machine, we should:
1. Check the different screws on the equipment regularly to see if there is any looseness. A correct understanding of some specific situations and a proper understanding of the corresponding requirements will be guaranteed for the subsequent use, so everyone should really pay attention to this aspect.
2. Do a good job of basic cleaning, especially every time you stop using the equipment, you must do a good job in all aspects of cleaning, so as to ensure that the equipment is not corroded, and it can also ensure the effect in the application process. If the performance is not well done, sometimes there will be greater errors, and the effect is difficult to guarantee.
3. Lubricating oil should be applied to key parts frequently to avoid rusting of key parts due to temperature and other reasons, and excessive friction of parts will affect the normal use of equipment.
Correctly do the daily maintenance and maintenance of the paper sizing and coating machine, and check some aspects of the machine every once in a while to see some conditions of the equipment, especially the problem of loose screws. In the process of maintenance, we should also do a good job in cleaning, and we can do a good job in these aspects. After the entire cleaning work is done better, then there will be more for our next applications. It’s a guarantee, so be sure to do these things in advance.
The development of the dryer section of the paper machine:
1. Single dry blanket drying device of paper machine
The drying section of a traditional multi-cylinder paper machine is equipped with two upper and lower drying cylinders with double blankets. In order to effectively exhaust the moist air in the drying section and obtain good ventilation effect, a dry blanket with high air permeability should be used. However, this kind of high air permeability dry blanket can effectively exhaust the moist air while also bringing the strong airflow into the bag area, which causes the problem of paper jitter in the production of low-quantity high-speed paper machines, that is, the paper sheets in the upper and lower cylinders without supporting sections. Fluctuations and flapping occur, wrinkles and paper breaks occur at the edges of the paper. The wet paper at the wet end of the drying section is very fragile and easy to break. The higher the speed, the more severe the jitter, and the easier it is to break. A more effective way to solve this problem is to use a single dry blanket configuration. As shown in Figure 6-2, the lower dry blanket is cancelled, and the upper dry blanket takes paper sheets around the upper and lower drying cylinders. Therefore, in the traction part between the upper and lower drying cylinders, the dry blanket also supports the paper sheet, and the paper sheet is not affected by the traction force, thereby reducing the shaking, wrinkling and breaking of the paper sheet. At the same time, air pockets are eliminated, the moisture in the horizontal direction of the paper is even, the drying cylinder can be approached without the need for the blanket roll; the paper is dried without traction, avoiding the longitudinal stretching and the horizontal when being dried by the traction. Excessive shrinkage can improve the quality of the finished paper.
2. Paper machine single-row dryer drying device (SymRun drying)
The above-mentioned single-dry blanket drying device can effectively control the shaking of the paper sheet and reduce the breakage for the medium and low speed paper machine with a vehicle speed of 500m/min or less. However, when the vehicle speed is further increased, its effect is greatly reduced, and the lower row of dryers has little effect on drying, resulting in a SymRun drying device with a single row of dryers and a single blanket configuration.
3. Paper machine opti drying device
The main shortcoming of the single-row drying cylinder drying device is that the drying device is longer. In order to overcome this shortcoming, many R&D workers began to develop a new and reliable drying method many years ago. The main purpose is to improve the drying unit. Length of drying efficiency, running stability and obtaining excellent paper quality. The Opti drying device is a new type of drying device that integrates excellent operational stability, maximum drying capacity and best paper quality. At the same time, the length of the drying section is about 25% shorter than that of a single-row dryer.
4. Opti drying device with pre-drying device for paper machine
In Opticoncept's entire technology, the opti drying device with pre-drying device is an ideal drying form. The goal of Opti drying with pre-drying is to significantly improve the control and running performance of the paper, especially at the beginning of the dryer section. The Opti drying device with pre-drying is an efficient drying method following OptiPress. The paper web is transferred from the press section to the pre-drying section through a fully enclosed dry blanket. Therefore, when the paper enters the first drying cylinder of the drying section , It has obtained a higher temperature and dryness, which greatly improves the running performance of the paper web in the first drying cylinder of the drying section, which is a key part, and also obtains a higher drying capacity.
5. Condebelt drying device for paper machine
The double-steel belt drying device is currently mainly suitable for the drying of cardboard. The vehicle speed can reach 850m/min and the cutting width can reach 4.6m. According to reports, the double-steel belt drying technology not only has high drying efficiency, saves raw materials, and has great potential for heat recovery, but also can be significant Improve the quality of cardboard. This is mainly because it can increase the tightness of the cardboard by 10%-40%, thereby greatly increasing the bonding force between the fibers and increasing the strength; if the strength is maintained, the basis weight can be reduced by 20%-30%, which saves a lot of fiber raw materials. Can use waste paper pulp to produce box board and kraft box board equivalent to virgin fiber pulp.
Installation of slitting rewinder After opening the box, the slitting rewinder should check the integrity of the machine, check whether there is any damage during transportation, etc., and then install the correction level on a flat and solid foundation after the inspection is not damaged. When we all operate and use the slitter rewinder, what are the factors that cause the rewinder to stain paper?
1: The speed ratio is different. In order to save costs, some manufacturers adopt the processing method of fine-grained surface and large-grained interlayer, which also caused the paper sticking problem of the rewinder.
2: The raw materials are not good enough. Use the cheap half-wood pulp shaft. Due to the large amount of impurities, the phenomenon of paper sticking is easy to occur during use.
The lifting mechanism of the rewinder should rise and fall steadily and rise and fall in parallel. The bottom knife roller and the upper knife axis should be parallel to the bottom roller, the distance to the bottom roller should be accurate, and the rotation should be flexible. After the slitter rewinder is installed and calibrated, check whether all the parts are intact, whether the connecting bolts are tightened reliably, and whether the movable parts are flexible, and then fill the lubrication parts with corresponding lubricating oil. Clean, clean, check and refuel. It can be turned on after confirming that it is correct.
The net trough structure of the cylinder paper machine is usually made of wood, and the main part of the trough ring is sometimes lined with metal (usually stainless steel), and sometimes also made of plastic. The so-called mesh groove ring refers to the annular gap between the surface of the mesh cage and the semicircular body. The ring of the mesh slot must be carefully constructed, and its shape must be symmetrical and smooth.
There are many forms of paper machine mesh slots. The longest used form is the downstream mesh trough and the countercurrent mesh trough. At present, the most widely used in our country is the movable arc-shaped plate type mesh groove, as well as the dry type mesh groove, the rotary former and the drum vacuum former, etc., in the more advanced paper machine, the suction type cylinder is used.
The structure of the paper machine's slot has a great influence on the output and quality of paper. Various net slots have certain characteristics. These characteristics may be advantages for the production of one paper grade, but may not be important for another paper grade. The mesh slot should be designed or selected according to specific production requirements. The general requirements for the design of the mesh tank structure are: the fibers of the pulp in the mesh tank are evenly dispersed without agglomeration; the pulp in the mesh tank has a uniform flow rate across the width; the pulp channels of the mesh tank are smooth and straight, and the corners should be smooth. Transition to prevent slurry hanging and sedimentation; easy to clean and repair.
There are mainly the following types of online slots for paper machines:
1. Ordinary downstream network slot
The fiber flow direction in the ring of the mesh groove is the same as the rotation direction of the mesh cage. The slurry flow enters the mesh trough through the branch spreader or the cone spreader and other slurry distribution devices. First, it is fully mixed in the flow part (head turning box) to promote the uniform dispersion of the fibers and remove the foam, and then overflows the spray plate and flows into the mesh. Inside the cage. The distance between the spray plate and the mesh surface of the mesh cage can be adjusted to control the flow rate of slurry entering the mesh tank. Lip cloth (also called skirt cloth) is a piece of rubber with a thickness of 1-2mm, which can prevent the slurry flow from directly rushing to the surface of the forming wire, and make the slurry flow change direction and flow down along the arc-shaped bottom of the mesh groove. The height of the adjustment lip cloth position is adjustable to control the position where the paper web begins to form.
The arc-shaped bottom of the mesh trough and the surface of the mesh cage form a horn-shaped pulp channel. The size and shape of the horns have a great influence on the quality of the paper. Usually, the distance between the curved bottom and the net cage is 130-140mm at the entrance of the slurry; then it is gradually reduced to 100-110mm at the bottom of the net trough; it is 70-80mm at the front of the overflow box. If the horn channel is too small, the pulp flow speed is too fast, which is easy to bring in air and form bubbles; when the horn channel is too large, the pulp speed is too slow, increasing the friction between the pulp and the wet paper web already formed on the mesh cage , Affect the evenness of the paper.
There is an overflow box at the end of the horn channel to eliminate the settlement of the fibers in the mesh groove and avoid the occurrence of excessively concentrated pulp mass. The width of the overflow box is 100-200mm and the depth is 200-300mm.
Downstream mesh tanks are characterized by a large dewatering arc length, and can use low-concentration pulp. The finished paper has better uniformity, greater tightness, and smoother. Its structure is relatively simple, it can be adjusted appropriately by spray plate and lip cloth, and it is easy to clean. It is suitable for papermaking of various cultural paper, general thin paper, base paper, paper string paper, oil-sealed paper, etc.
2. Counter-current mesh trough
The basic components of the countercurrent mesh trough are the same as the downstream mesh trough, but the direction of rotation of the slurry flow and the mesh cage is opposite. The pulp concentration is greatest where the paper web begins to take shape. The rotation of the net cage has some stirring effect on the pulp, causing some intertwining of the fibers, so the ratio of the vertical and horizontal tensile strength of the finished paper is small; the wet paper formed by it is looser, and the surface has upright fibers, which makes the paper layer and paper It is easy to combine the layers, so the counter-flow mesh groove is often used for making thick paper, pulp board or cardboard with multi-cylinder net.
The feature of the counter-current mesh tank is that the requirements for pulp are not strict, and the same structure of the mesh tank can be used for pulp with very different properties, which is easy to operate and control. The mesh trough has a simple structure, no overflow and lip cloth, and is easy to clean. The disadvantage is that the evenness of the finished paper is low and the speed cannot be too high.
Downstream mesh troughs have better uniformity than countercurrent mesh troughs, while countercurrent mesh troughs can take a higher quantitative. Therefore, in practice, the downstream mesh grooves are often used to produce the outer paper web, and the countercurrent mesh grooves are used to produce the middle layer paper web.
3. Movable curved plate mesh slot
In the head turning box part of the movable arc-shaped plate type mesh tank, a bubble grid (or called an exhaust grid) is arranged near the arc-shaped plate to discharge the air in the slurry. The pulp first enters the directional pulp channel of the pulp flow from the tip box. The directional pulp channel is composed of a fixed arc groove bottom at the bottom of the mesh groove, a lip cloth and the lower arc of the movable arc plate, which is used to control the direction of the pulp on the net and stabilize the pulp flow. Subsequently, the pulp enters the fixed-speed pulp channel of the mesh trough, that is, the pulp channel composed of the movable arc-shaped plate and the mesh cage. The curved surface of the movable arc plate is a circular arc made with the center of the cage moving down 20-40mm, and the radius of the cage larger than the radius of 40-60mm. There is a movable pivot in the middle of the movable arc plate, which can be pushed by screws for horizontal translation to adjust the distance between the movable arc plate and the surface of the net cage, so as to control the flow rate of the pulp and meet the requirements of vehicle speed and paper web basis weight. . At the same time, the movable arc-shaped plate can also use the screw on the upper edge of the mesh groove to rotate around the movable pivot, thereby changing the shape of the pulp channel, that is, changing the size of the entrance and outflow end of the pulp channel to adapt to the nature of the pulp and the overflow rate. size. The overflow groove of the pulp is arranged at the upper end of the movable arc plate.
The movable arc-shaped mesh trough is characterized by greater adjustability and is suitable for variable production varieties; the pulp sizing head is larger, and correspondingly has a larger dewatering capacity; but the white water concentration is large, and the fiber loss is more. The side of the paper against the net is rough. The movable arc-shaped mesh slot can be used in the production of printing paper, letterpress paper, writing paper, general thin paper, toilet paper, packaging paper and other products. It is a widely used mesh slot structure type at present.
4. Suction type rotary screen and pressure type mesh trough
(1) Aspiration type rotary screen
The various mesh slots mentioned above can generally only adapt to lower vehicle speeds. When the vehicle speed is increased, the phenomenon of pulp shuffling and slipping is prone to occur, and it is difficult to ensure the quality of the finished paper. The use of aspirated rotary screen is beneficial to increase the speed of the rotary screen.
Close the two side boxes (that is, the ear boxes) of the downstream mesh trough, block both ends of the mesh cage (white water in the mesh is drained by the water legs), and seal the part of the mesh cage that exposes the slurry surface with a rubber cloth to make the mesh cage The inside and outside of the cage are basically isolated; a low vacuum of 0.8~1kPa is created in the cage with an exhaust fan.
The use of this kind of mesh groove enhances the water filtering capacity of the mesh cage, increases the adhesion of the pulp on the mesh surface, and reduces the influence of centrifugal force, thereby creating favorable conditions for increasing the speed of the circular mesh. In addition, the suction type mesh groove can improve the uniformity of the paper, reduce the moisture when the wet paper web enters the flat roller, and reduce the phenomenon of water and pulp flutter from the flat roller. The transparent spots often found on the paper made by the rotary screen are mainly caused when the wet paper web leaves the pulp surface. The air-exhausting mesh groove can eliminate this paper defect.
(2) Pressure type mesh trough
The mechanism is to cover the forming part of the mesh trough on the basis of the common downstream mesh trough, and use a blower to send in 400-500Pa air of up to 1kPa for pressurization. The main purpose of this former is to improve the forming of the paper web to improve the evenness of the paper, at the same time to increase the speed of the car, increase the output, and also to eliminate the phenomenon of pulp rejection caused by high speed.
There are two types of pressurized rotary screen: BF type and BO type.
The BF type is a mesh trough similar to the movable arc-shaped plate in our country. It uses multiple pipes to feed the slurry, then enter the diffusion mixing chamber, and then go online through a homogenizing roller. The forming part is covered and closed by air and pressurized. It is used for papermaking tissue paper, the design speed is 300m/min, and the papermaking basis weight is less than 30g/m2. When the vehicle speed exceeds 200m/min, the inside of the cage needs to be exhausted.
The BO type is a downstream mesh tank, which also uses multiple pipes to feed the slurry, then enter the diffusion mixing chamber, and then enter the arc-shaped channel through the homogenization roller to go online. The forming part is covered and closed by air and pressurized. Used for papermaking of multi-layer paperboard, the speed of high-grade white paperboard is 122m/min, and the general paperboard can reach 160m/min. The papermaking weight of each net is more than 30g/m2. The bottom net is 8-12 mesh stainless steel net when producing paperboard. The surface mesh is 55 mesh copper mesh or stainless steel mesh. The sizing concentration is about 0.2%.
The characteristic of the pressurized cylinder is large dewatering capacity; the interlayer of the paper produced is well combined and is not easy to peel off; because the forming part has a small positive pressure, the paper web is formed with a filtering property. Compared with the vacuum cylinder, the paper There is less loss of fine fibers on the web surface, and the two-sidedness of the paper is small; the evenness of the finished paper is better than that of the ordinary cylinder; the lateral basis weight difference of the paper web is better than that of the paper copied by the ordinary cylinder; the speed of the paper can be increased.
5. Dry-type net troughs and restricted net troughs
(1) Dry net trough
A simple sealing device is installed in the mesh groove ring to confine the slurry suspension to a shorter area of the mesh groove ring. Due to the reduced length of papermaking, the degree of uncontrolled turbulence in the forming area is reduced; at the same time, white water can enter the net cage smoothly to avoid accumulation in the net cage. The width of the whole machine is more uniform in dewatering, which improves the quantitative distribution of the banner accordingly. The scouring effect of the countercurrent and downstream mesh grooves is greatly reduced, while the overall forming capacity is not reduced.
(2) Restrictive mesh slot (half mesh slot)
It is actually a dry mesh tank with "empty" semi-dewatering.
The above is the type of the network slot of the cylinder paper machine.
Analysis of the factors that interfere with the accuracy of the width of the rewinder
1. During the operation of the rewinder equipment, if the tool has a problem of lateral swing, it will cause a bad size, such as the lateral swing of the tool and the difference in the outer diameter of the tool. Because the tool's lateral oscillation value cannot be zero. Generally, the lateral swing value of its load is about 0.03-0.05mm. The reason is the accuracy error of knife thickness, inner diameter, spacer width, etc., and the warpage caused by the lateral stress when the thick plate is sheared.
2. During the production of the rewinder equipment, due to the problem of lateral warpage of the steel plate, the width dimension is not good. This is because the product cut under the lateral warping state is larger than the set value of the knife.
3. Due to the production and operation of the rewinder equipment, there are corresponding matching errors in the spacer sleeves and cutters. Normally, the thickness accuracy of spacer sleeves and cutters is 0.005. When the number of blades is large, the accumulated error becomes larger. This is because the upper tolerance setting is not good. It should be understood that the width of the product cut by the rewinder is always slightly lower than the size of the product side with the knife. Therefore, it is necessary to predict the degree of this drop in advance. When arranging the knife on the product side, refer to the size of the spacer sleeve when confirming it.
The rewinder is a special equipment for papermaking. The purpose is to sequentially rewind the paper rolls (called base paper rolls) produced by the paper machine. After the paper passes through the rewinder, it is made into finished paper and leaves the factory. At present, the use of AC drives in rewinders instead of DC drives has become a development trend in the tissue processing equipment industry.
The rewinding machine is mainly used to convert large toilet paper from a single-layer rewinding and slitting machine to a single-layer, two-layer or three-layer specification for folding paper towels, napkins, boxed facial tissues, etc. This rewinder adopts well-known factory blades, vacuum suction edge, fixed upper knife angle, neat cutting, stable operation, and is an ideal supporting equipment for paper mills or paper mills.
When using a rewinder, you will encounter a rewinder failure. The maintenance of the rewinder is as follows:
1. The transmission of the rewinder, such as the gear chain, needs to be lubricated for a period of time.
2. Rewinders usually do not cause problems. The wearing parts are nothing but pinions. If one is added, the printing knife can easily break. After one and a half years of use, the wool roller will become thinner. It needs to be sent back to the factory for repair. If you need to change the embossing pattern on the steel roll embossing device, you need to transport the steel roll back to the original factory for modification, and the cost is not high.
The pipe cutting machine is based on the environment where the pipe is curved outside. The reason should be carefully elaborated. At first, the pipe should be covered with a fine heat treatment punishment. The welded seam of the steel pipe is not subject to the stress of F1 and F2. Bias, that is, do not face the clamping die and bending wheel die; the boost and push rates are determined according to the actual environment of the pipe cutting, so that it is in a room that is opposite to the speed of the pipe cutting machine. At the same time, it should be checked whether the advancement of mandrel placement is appropriate and the necessary mediation must not be held at that time. After removing the factors of the pipe, check whether the pressure of the compaction die is too large, and adjust to make the pressure appropriate.
To deal with the newly used mandrel, check whether the diameter is too large. When the diameter is too large, it is necessary to carry out the necessary grinding and ensure that the mandrel and the inner wall of the pipe are well lubricated to eliminate the resistance of the bend and the friction between the inner wall of the pipe and the mandrel. At the same time, accept the proper steps to stop the machine from shaking. If the post-cut point is wrinkled, an anti-wrinkle block should be installed, and the position of the anti-wrinkle block should be accurate, and it can be attached to the pipe cutting machine mold, and the pressure of the compacting die (wheel) must be adjusted to make the pressure appropriate. To cope with wrinkling inside the arc, the corresponding step should be accepted according to the wrinkling position. If the front cut point is wrinkled, the position of the mandrel should be adjusted forward so that the mandrel is properly measured in advance to support the pipe when it reaches the bend.
The composition of papermaking waste residue is complex. To realize resource recovery, it must be sorted and removed. However, the amount of slag is large and the sorting is difficult. The original equipment on the market only uses the traditional washing and rinsing method to sort out a small part of the recycled granulation. The rest of the burial method is used badly, which brings pollution hazards to the soil and harms future generations.
The papermaking waste recycling technology equipment combines the characteristics of papermaking wastes, draws on the technical characteristics of related equipment at home and abroad, and according to the different components of papermaking residues, on the basis of selecting suitable disposal processes, each technical problem is solved one by one. After repeated tests and improvements, a unique comprehensive utilization equipment for papermaking waste residues has finally been formed. Through screening, flotation, magnetic separation, wind separation, dehydration and supplemented by necessary candidates, the scientific classification of papermaking waste is realized, and the separated scrap metal, broken glass, sand and gravel, pulp, rags, grass The residues such as rope are directly recycled and reused and incinerated to generate electricity, which opens up a new way for the harmless, standardized disposal and resource utilization of papermaking waste.
There are many factors affecting the forming of a paper machine, some of which are factors affecting dehydration, and some factors are "congenital" to the forming process, such as the characteristics of fibers in the pulp, the ratio of pulp, etc. Some factors are Due to the characteristics of the former, such as shaking, double-sided dehydration of the mesh, etc., some factors can be adjusted during the production process. The editor of Zibo Tianyang Paper Machinery Co., Ltd. will share the following
1) Pulp concentration
Low pulp concentration can increase the mobility of the fibers. When the turbulence and shear disappear, the time required for the fibers to form a flocculated state in low-concentration pulp is also longer than that in high-concentration pulp. Groundwood pulp with shorter fibers Fiber as an example, when the concentration is 1%, the flocculation time is about 100 milliseconds after the influence of disturbance disappears, only 1 millisecond when the concentration is 4%, and about 500 milliseconds when the concentration is 0.5%, so the low concentration has Conducive to better dispersion of fibers.
The reduction of pulp concentration on the Internet also enhances the activity of fine substances, and the loss of fine substances also increases when the initial water discharge is fast. , forming a net.
During the deposition process, the higher the content of fine fibers and fine substances in the laminate near the mesh surface, the better the surface of the laminate and the undulations and concavities of the mesh surface, that is, the clearer the net marks reflected by the laminate. , the net marks are strengthened. It can be seen from the above situation that when the pulp concentration on the net is low, the opportunities for fine fibers and fine substances to move to the net surface increase, so the net marks also tend to be strengthened.
2) Dewatering speed of paper machine
The influence of dewatering speed on the forming process and forming quality is multi-faceted. The initial dewatering speed of pulp feeding on the web is very different from the speed of dewatering of the free suspension above the layup in the later stage of the forming process through the formed layup.
When the initial dewatering speed is high, the defects in the fiber distribution caused by the flow section will be quickly fixed, the loss of fibers and fine particles will increase, and the web marks of the wet paper web will be enhanced. The result of passing through the layers.
Except for some thin papers, measures are usually taken to slow down the initial dehydration speed, so that the dehydration in the early stage of the forming process is relatively gentle, and at a relatively gentle initial dehydration speed, the orientation of the fibers in the lower part of the laminate can be easily controlled. , reducing the tendency of fibers to be arranged in the direction perpendicular to the forming mesh surface, which is conducive to better dispersion of fibers in the drainage.
3) Speed difference of pulp wire of paper machine
The speed difference of the pulp web is a measure to apply directional shearing. The speed difference of the pulp web is large, the directional shearing in the longitudinal direction is also large, and the orientation of the fibers in the longitudinal direction is also strong. The further away from the forming wire, the weaker it is.
The directional shear produced by the speed difference between the pulp and the web also has a good effect on the dispersion of the fibers in the undrained free suspension. The pulp speed is slightly faster or slower than the web speed, which reflects the improvement of fiber uniformity during the forming process. The effect of too large speed difference between pulp and web on forming is bad.
4) Paper machine forming wire
The forming wire is an essential element involved in the forming process, and the dewatering of the fiber suspension on the forming wire is related to the effective flow area and mesh size of the forming wire.
The effective circulation area refers to the sum of all mesh areas in the unit forming mesh area, and the mesh size is the specific size of a single mesh. The effective circulation area is related to the number of meshes and the diameter of the warp and weft threads. In a single-woven net, the effective circulation area is usually smaller for those with more meshes, because the warp and weft lines increase. When the effective flow area is more than 80 meshes per inch, the effective flow area usually increases with the increase of the mesh. Under the conditions of the same pressure difference and flow resistance, when the effective flow area is large, the dehydration speed is also higher. The effective flow area is the same but the mesh number is higher. For a long time, it means that the size of the mesh is small, and the dehydration speed will decrease due to the increase of flow resistance.
5) Pulp temperature
The increase of pulp temperature can reduce the viscosity of the water in the suspension and increase the dehydration speed. The fiber suspension is originally a three-phase suspension, because there will inevitably be more or less air in it, increasing the pulp temperature. It is conducive to the rapid escape of the gas phase in the suspension under the condition that the volume increases rapidly, so that the flow conveying part or the attached degassing device has a better degassing effect. However, the increase in pulp temperature also creates favorable conditions for bacterial reproduction, and it is easy to form viscous pulp in the pulp and form fouling in pipes and machines, reducing the quality of pulp or causing secondary waste in paper production. When the white water closed circulation system, the above problems caused by the increase of pulp temperature are more likely to occur.
Advantages and innovations of pipe cutting machine:
1. Greatly improve and mitigate installation safety and fire safety;
2. Precision cutting, both sides of the pipe are flat after cutting, which is convenient for connection
3. The cutting method is simple, fast and saves a lot of working time;
4. Provide a light working method, which can be designed according to the workplace (on-site);
5. High safety, no need to move the pipe by hand when working;
6. It will not produce sparks and dust to the outside when cutting;
7, full-featured, can cut all kinds of built pipelines of the power system;
8, cutting pipes are made of materials such as: steel, stainless steel, cast iron, copper, plastic, multilayer pipes can be cut;
9. No specific requirements for pipe diameter and working platform;
10. Good quality and reasonable price.
The complete part of the paper machine finishing section, the complete set of equipment that links the pulp to the paper web is called the paper machine, which includes the head box, wire section, press section, drying section, calender, roll machine and transmission section. Main machine and auxiliary systems such as steam, water, vacuum, lubrication, heat recovery, etc.
Multi-process treatment to achieve good surface quality. Most papers are calendered by a mechanical calender behind the paper machine to make the paper smooth and consistent. The mechanical calender is made of several cold cast iron rollers, and the paper surface is flattened by the weight of each roller or another pressure. If a higher surface smoothness is required, use a super calender to calender. It is generally composed of pulp rolls and cold cast iron rolls arranged alternately. According to different usage requirements, some varieties need surface sizing to improve surface quality; some have to be surface coated to improve appearance quality or printing quality. Surface sizing and coating can be processed with paper forming outside the paper machine through the sizing machine and coating machine, or the sizing machine and coating equipment can be combined in the paper machine for in-machine processing.
The wastewater treatment method of paper machine should adopt different wastewater treatment methods according to different production processes and different production conditions.
Paper machine's wastewater treatment should focus on increasing the rate of recycling water, while reducing water consumption and wastewater discharge, reducing production costs and decontamination costs in all aspects. Different paper machine production processes can be processed according to local conditions, which can greatly improve the processing efficiency.
When treating paper machine kraft paper wastewater, BOD can be removed by biophysical methods, and wet oxidation can be used to treat sulfite pulp wastewater. Of course, the domestic treatment methods are different. Generally, reverse osmosis, ultrafiltration, and ultrafiltration are used. Wastewater treatment methods such as electrodialysis.