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Paper dryer cylinder refers to a machine used in papermaking machinery to continuously dry the paper blank after the pulp is formed. Dozens of drying cylinders are placed crosswise in a paper machine. The paper drying cylinder is a roller-type pressure vessel, with rotatable shafts on the heads at both ends, and the steam for drying paper is passed through the inner hole of the hollow shaft at one end. There is also a bucket containing water in the cylinder to send the condensed water into the hollow shaft at the other end for discharge. The drying cylinder is generally made of cast iron and polished on the outer surface. The paper blank and the cylinder surface can be easily separated from the surface of the cylinder by using the characteristics of multiple graphite flakes in the cast iron, so that the paper will not be stuck when the paper is dried.

The drying cylinder of the paper machine is commonly called the dryer cylinder. The drying cylinder is generally composed of a roller and a supporting shaft. The drying cylinder shaft is usually made of cast iron. In order to facilitate the maintenance of the bearing and the shaft, it can be divided into two categories: expansion fit and taper fit. There are many reasons for wear and tear, and if it is not handled in time, it will have a serious impact on paper products and equipment.

The dryer cylinder is a hollow cylinder made of cast iron with covers at both ends. It consists of a cylinder body and cylinder heads at both ends. The outer diameter is mostly 1000～3000mm. During operation, the conveyed paper will be dried by steaming inside. Burned. Dryer wear problems are very common in industrial equipment.

1. Causes and analysis of the abrasion of the dryer cylinder shaft of the paper machine

(1) The reason for the fit size is mainly caused by the error during machining.

(2) The reason for assembly depends on the assembly process and technical means.

(3) The reason for the use of the bearing is that the temperature of the bearing during use is too high, and it bears the axial force and the radial force at the same time, which leads to the interference size metal fatigue between the shaft and the bearing and the matching clearance. Once the matching clearance occurs, the bearing and the Relative movement between the shafts aggravates wear, and in severe cases, the bearing or dryer shaft is scrapped, causing a vicious event.

(4) Normal metal fatigue wear: The metal itself has certain fatigue characteristics. Long-term torque will lead to normal fatigue wear of the metal. This phenomenon is determined by the characteristics of the metal itself. Therefore, only the shaft production process can extend the metal fatigue by improving the production process. Cycle to increase service life;

(5) Lubricating oil quality problems: lubricating oils generally used are divided into synthetic oils and petroleum-based lubricating oils. Lubricating oil has a certain degree of anti-wear, pressure resistance and viscosity-temperature properties. Therefore, inferior lubricating oil generally cannot adapt to the high temperature environment of the dryer operation during the use process, resulting in the rupture of the lubricating oil film or the inability to form an effective lubricating oil film, resulting in poor bearing lubrication. Therefore, the friction coefficient during the operation of the bearing is large, which causes a large torque force to be formed between the inner ring and the shaft surface, causing damage to the bearing and subsequent shaft wear;

(6) Improper maintenance: Failure to replace the bearings in time or poor lubrication is also one of the main reasons for the wear of the dryer cylinder shaft;

(7) Withdrawal sleeves, adapter sleeves or tightening nuts are loose, resulting in gaps in the mating surfaces, resulting in shaft wear.

The failures that often occur in paper machines include two aspects: one is the inherent production failure downtime.

Paper-making machinery and equipment are carried out on the premise of ensuring product quality and meeting the requirements of the production process, especially the production of cultural paper, but it is relatively simple to handle; the second is equipment downtime. In the production process of paper machines, there are certain particularities and complexities. If the equipment fails, we need to find out the cause and deal with it in time to avoid turning the small problem into a big one. The same is true for paper machines. Let's talk to the editor of Tianyang Paper Machine to learn about the analysis of paper machine equipment failures and how to solve Fu Juan's cracks.

Features of equipment failure shutdown:

1. There are many equipment failure points, often accompanied by equipment failures.

2. The service life of the parts is relatively short, resulting in a high replacement frequency.

3. Management is difficult. There is a gap between the period of failure and the time taken by the repair station.

The main reasons for the failure of papermaking machinery and equipment include:

1. Wear and tear

It mainly includes parts and equipment such as pulp, pulp pump, vacuum box board, desander, calender, press roll and other parts and equipment that have long-term contact with copper mesh, pulp, felt or forming paper. Fault. Another reason is the frequent movement of parts.

2. Lubrication

With rotating rolls and hundreds of different types of bearings in paper machines, lubrication management is necessary, especially under the influence of water, heavy loads and high temperatures. Lubricating oil is easy to evaporate, lose and age, causing damage and wear of the shaft head bearing, so it is necessary to check and refuel regularly.

3. Fatigue

The heavy load and continuous operation of papermaking machinery and equipment are easy to cause fatigue damage. In the paper machine, due to the limitations of the mechanical structure and working principle, the parts cannot have too strong design strength to avoid damage. It can be solved by maintenance and technical transformation.

How to solve paper machine rewinding cracks:

1. The uneven hardness or moisture content of paper rolls in papermaking machinery should be improved.

2. Whether the setting of the stretching device is normal.

3. Remove pulp lumps on the dryer cylinder, draw roll or spreader roll.

4. Before installing the paper core on the rewinder, check to make sure that the size of the paper core is the same as that of the shaft end.

5. Check the longitudinal knife.

6. Reduce the blowing pressure on the whole side to prevent edge cracks caused by excessive blowing on the whole side.

7. Replace or regrind damaged slitting knives.

8. If the vertical knife setting is shallow, lift the vertical knife cutting handle.

9. The roll paper is too tight.

Our country’s paper machine branch transmission equipment used SCR DC speed regulation in the past. Due to the existence of slip rings and carbon brushes, the reliability and accuracy of the paper machine are not high, which leads to the backwardness of the paper machine machinery and the speed is only about 200m/min, which is difficult. Compared with foreign high-speed paper machines of 1000m/min. From this point of view, the frequency conversion of the paper machine branch transmission machinery is the general trend.

Divisional transmission involves many transmission points such as the wire section, press section, front dryer, rear press, rear dryer, calender, etc. of the paper machine. Because the paper has the shortcomings of thinness and fragility, in order to prevent the paper from breaking , Curl, wrinkle, indentation, high-precision speed control must be carried out on each transmission point, and the paper must be stretched according to the stretch rate limited by the direction of the paper. In other words, in the whole process from sizing to winding, the paper web must be cascaded at a certain speed, so that there is tension.

It is the frequency conversion control based on the sub-drive that emphasizes the on-line stepless speed regulation and synchronous following performance of each transmission point. Therefore, the frequency converter used in the sub-drive must have the following characteristics:

1. The speed range is wide, and the efficiency must be above 90% in the full speed range.

2. The power factor is higher than 0.9.

3. The total distortion of the input harmonic current is less than 3%.

4. Adopt standard IGBT with high reliability and mature technology.

5. It can reduce the output harmonic components and effectively reduce the effect of dv/dt noise and torque ripple.

6. Use the communication function to realize high-speed serial transmission of data.

For example, the power of the 4 branch transmission points of a 1092 tipping paper machine in a paper mill is 11kw for pressing, 11kw for main cylinder, 7.5kw for group cylinder, and 5.5kw for roll paper. Another example is the 2820 kraft boxboard paper machine of a certain factory. The frequency converter adopts the American AB company 1336 type high-function frequency converter, the PLC adopts the AB company SLC500 series, and the operation interface adopts a touch screen. The upper computer controls the storage of operating parameters, the automatic generation of data tables, the automatic printing of production reports, and the analysis of fault alarm status. The network communication adopts the international PROFIBUS DP communication network. The motor adopts AC variable frequency motor, and uses magnetic flux vector closed-loop control. In addition, the load distribution of each transmission point can be controlled by calculating the actual power used by each transmission point, and in the production process, local tension and relaxation can be performed without affecting the speed chain by inching.

The above two examples are more typically applied to the control principle of the divisional frequency conversion control. The control principle of the divisional transmission is to maintain the speed cascade and high-speed transmission. The former uses the upper computer (PLC or industrial computer) to calculate the speed cascade. The latter is achieved through the high-speed serial communication capability of the inverter itself. In this way, the entire system has simple wiring, high degree of automation, rich information and compatible interfaces, which facilitates the integration of FA and management and control.

The result of the speed cascade is to form a series of speed chains for the main transmission points of the paper machine subsection transmission. As long as the speed of one of the points is adjusted, each subsequent transmission point is also adjusted quickly. In the actual paper machine control, it is often necessary to add a specific transmission control method according to a specific position, especially the important parameter load ratio control.

The so-called load ratio control means that in order to maintain the tightness and reasonableness of the contact between the two intermeshing rollers, the load distribution of the two rollers is required to achieve the best effect. In the control of the engagement rollers of the press section of the paper machine, the calender, etc., according to technological requirements, when the paper web breaks, the two engaged rollers are in the disengaged position, and the two rollers are in the closed position when the paper web passes. Among them, in the meshing roller closing, in order to maintain the close contact between the two rollers on the machine maple and meet the meshing requirements, a load ratio control method is required.

The main drive of the meshing roll of the paper machine still adopts the speed cascade control mode, and the secondary drive adopts the load ratio control mode. In this load ratio control, the speed closed-loop setting value is added to the main drive setting value (V setting), and the speed is increased by 5%. In this case, the output value of the speed loop is that of the current loop. The set input value (M setting) will increase, and then the output value of the main drive speed loop is multiplied by the load ratio percentage value to limit the set input value (M setting) of the secondary drive current loop, and it will be tight. Keeping up with the main drive makes the meshing degree of the two rollers closer and closer.

Many domestic paper mills often encounter the phenomenon of drying cylinder sticking in the production process. This phenomenon may cause the paper surface to be not smooth enough, the wrinkles to be uneven in thickness, and in severe cases, it will cause holes or opaque spots, and sometimes have to stop. deal with. There are many and complex reasons for paper sticking to the cylinder. The main reasons include:

1. The slurry is not clean.

2. Dispersing agent, wet strength agent and dry strength cutting agent are not used properly.

3. The specific pressure is too large during refining, and the temperature rise is too high.

4. When the paper material is put on the Internet or on the tank, if the pH is greater than or equal to 7. O.

5. The structure of the dryer is not strict, the surface is not smooth, and even there are many tiny pores, which will also cause the paper to be difficult to scrape off after being loaded into the cylinder.

The headbox is the heart of papermaking and is essential for obtaining high-quality paper. We provide headboxes with excellent performance, low energy consumption and low prices for paper mills. The following is the detailed information about the 2700mm headbox.

Lips: 2700mm

1. Its basic configuration is a square cone tube, stepped orifice plate cloth slurry, double-homogeneous roller rectification, vertical lip with sizing device lip, etc.

2. The surface of the headbox and the contact part of the headbox is mirror-polished. The cotton ball is used to reach the suspended yarn with a roughness of 0.4mm.

3. The defoaming device with stainless steel nozzle is above the liquid surface.

4. The headbox support is an oblong hole structure, which is easy to adjust.

Misleading properties of dehydration elements

(1) Purity

Given this characteristic, it is often mistakenly assumed that many of the operational benefits are obtained from 100% pure ceramics. But in many cases, the opposite is true. The performance of engineering ceramics can be improved by utilizing catalysts, binders and other trace elements. However, this does not apply to alumina and some other ceramic materials (eg silicon nitride). Some of these vitreous additions are chemically attacked, making the surface porous and rough. While higher purity ceramic materials are more resistant to chemical attack, other mechanical properties such as toughness may be sacrificed.

(2) Hardness

The surface hardness of a ceramic, which can be measured by its ability to resist scratching by another material, affects ceramic wear resistance to some extent, but cannot predict the rate at which the forming wire wears. Due to the complexity of ceramic crystal structure and hardness testing, caution is required when applying hardness values to predict wear resistance or impact on forming wire life. Actual reference information and empirical data are important.

(3) Grain size

The average value, main value and range of ceramic particle size can reflect the internal structure of ceramics, but cannot be used as a basis for predicting the performance of ceramic components in the paper machine.

(4) Friction coefficient

The coefficient of static or kinetic friction generated when the forming wire slides on the ceramic surface is very sensitive to the contact conditions, so no single data can be used. The drive load fluctuates wildly with factors such as ceramic structure, contact pressure, and amount of lubricating water. When the lubrication effect is poor, the wear of the forming wire is related to friction.

There are many fluctuations and complex contact conditions that need to be considered when analyzing the coefficient of static or dynamic friction of a forming mesh as it slides on a ceramic surface, so there is not yet a good description to define the friction conditions in this application area. The main concern of papermakers is the wear and transmission load of the forming wire, which varies greatly due to factors such as ceramic structure, contact pressure during application, amount of lubricating water, and type of forming wire. Selection of suitable wear resistant ceramic materials, regular grinding and maintenance of the ceramic edges will improve low friction operation.

Working principle of water centrifugal pump.

Working principle: Fill with water before starting. When the motor drives the water pump impeller to rotate at high speed, the water in the impeller also rotates. Due to the centrifugal force, the water rushes into the inlet and outlet pipes along the tangential direction of the impeller's circumferential rotation. After the water is discharged A vacuum is formed near the rotating shaft in the pump casing. The water in the inlet pipe is pressed into the pump to fill the vacuum under the action of external pressure, so as long as the impeller keeps rotating, water will continuously enter the pump from the inlet pipe.

The basic structure of water centrifugal pump:

The impeller is the core part of the centrifugal pump. It has a high speed and a large output. The blades on the impeller play a major role. The impeller must pass a static balance experiment before assembly. The inner and outer surfaces of the impeller are required to be smooth to reduce the friction loss of the water flow.

The pump body is also called the pump housing, which is the main body of the pump. Play a supporting and fixing role, and connect with the bracket for mounting the bearing.

The role of the pump shaft is to connect the motor with the coupling, and transmit the torque of the motor to the impeller, so it is the main part of the transmission of mechanical energy.

The sliding bearing uses transparent oil as lubricant, add oil to the oil level line. Too much oil will seep out along the pump shaft, and too little bearing will overheat and burn out causing accidents! During the operation of the pump, the temperature of the bearing is up to 85°C, and it generally runs around 60°C.

The sealing ring is also called the leakage reducing ring.

The stuffing box is mainly composed of packing, water seal ring, packing tube, packing gland and water seal pipe. The function of the stuffing box is mainly to close the gap between the pump casing and the pump shaft, and prevent the water flow in the pump from flowing outside and the outside air from entering the pump. Always maintain the vacuum in the pump! When the pump shaft and the packing friction generate heat, the water seal pipes the water to the water seal ring to cool the packing! Maintain the normal operation of the pump. Therefore, special attention should be paid to the inspection of the stuffing box during the itinerant inspection of the pump operation! The packing should be replaced after 600 hours of operation.

Papermaking equipment dewatering device, papermaking machine is the general name of the complete set of equipment that makes the pulp form the web of the linkage, including the headbox, wire section, press section, drying section, calender, roll machine and transmission section, etc. Main machine and auxiliary systems such as steam, water, vacuum, lubrication and heat recovery.

Transmission system

Connect the various parts of the paper machine to run synchronously, so that the machine and electricity are integrated. It is composed of mechanical deceleration device, speed regulating and speed stabilizing device, branch transmission device, etc., and all use electric power as the power source.

White water system is a recycling, processing and recycling system for the dewatering of the forming section of the paper machine. Including white water collection, transportation, filtration or sedimentation, air floatation and other equipment to separate and recycle fiber and filler for reuse, as well as the entire system for recycling clean white water in the papermaking process.

Pipe cutting machine What should I do if something happens in the trachea and airways? The correct way to deal with this failure is critical!

1, gas system failure repairThe gas line system can be checked frequently. There are two main aspects of common gas line maintenance. When leaks are found and parts that cannot be used normally, they should be disposed of in a timely manner to ensure that the air path is unobstructed; dust and debris on the air path should also be wiped away frequently to prevent premature aging of the air path.

2, Maintenance of pressure reducing valveAdjust the pressure gauge to the required pressure. For the maintenance of the pressure reducing valve, the pressure reducer should be adjusted first. During the adjustment, the pressure should be from small to large to ensure that the pressure reducer can be continuously adjusted. If the regulator cannot be continuously adjusted or the gas leaks from the safety valve, a new pressure reducer must be replaced. Folding the components of the gas pressure reducer by yourself will cause equipment damage and even severe personal injury.

3. Maintenance of Tempering PreventerAccording to the requirements of the safety part, the flashback preventer is an important part to ensure safety. It is strictly forbidden to dismantle the tempering arrester. Therefore, the gas barrier of the flashback preventer after a long period of use cannot guarantee the gas flow rate or leakage, so please ask professional staff to replace it.

4.Torch cutting nozzle failure and maintenanceIt is recommended that the user should use the original machine provided by the manufacturer, and purchase accessories. During long-term use, the sealing surface of the cutting torch is damaged, and the cutting nozzle is not tightly sealed. It must be repaired with special tools. In addition, the cutting torch also uses the standard fast cutting nozzles produced by professional manufacturers. For new cutting nozzles, they must be inspected before they can be used. The cutting nozzle is contaminated. Special tools are required to clean the preheated flame holes and cut the oxygen channel.

Installation and commissioning of paper machine. Now the paper industry has basically realized automatic mechanical production. For different paper types, many different types of paper machines have appeared. So what are the precautions for the installation and commissioning of paper machines? Today I will introduce to you:

1. Preparations before installing the paper machine:

1. The paper machine needs to be kept properly before installation, and the exposed parts should be coated with anti-rust grease as much as possible to prevent the surface of the machine from being rusted by wind and rain. Maintenance work is required.

2. The workshop should reserve sufficient height and position according to the size of the paper machine. The foundation of the paper machine should be made of high-standard cement and embedded with steel bars, and threading pipes or cable trenches should be reserved.

3. The manufacturer should be equipped with a lifting tool of 1-2 tons to prevent it from being used during installation and maintenance.

4. If the paper machine is not used for more than 6 months after leaving the factory, the equipment must be cleaned and inspected. After cleaning, lubricating oil is added to each part to prevent the parts from rusting and aging.

2. Installation of paper machine:

1. First, fix the transmission device of the equipment, control a certain height, use the level of the end plane, and fix the screws on the transmission equipment at the same time.

2. The main installation of the paper machine equipment follows the detailed steps in the manual.

3. Finally, the location of the steam pipe should be installed in accordance with the general drawing. Do not change and process arbitrarily. Pay attention to whether the pipe connection is sealed to avoid air leakage. After the installation of each component, a test machine is required.

3. Debugging (idling test machine):

1. No-load test machine is required after the paper machine is installed, and the main machine idling test machine time is not less than 1 hour; when the main machine runs smoothly, it can be produced slowly.

2. Each ancillary equipment of the paper machine also needs to be turned on without load to observe the operation effect, whether there is abnormality and noise, etc., it can be used if it is running normally.

3. In the process of empty machine test, ensure that the whole machine has no abnormal noise, and that there is no air leakage at the pipe joints, it can be put into normal use. Before that, the pipe joints need to be tightened again.

Customers fromTurkey visited EASTTAI factory and communicated with the technical engineers about relevant technical issues.The customer said that the products quality of EASTTAI is very good, the production process is very standard and they are very satisfied with EASTTAI service.

Turkey customers hope to continue their long-term cooperation with EASTTAI.

As one of the indispensable equipments for paper processing at present, the paper cutter is easy to use and must pay attention to the use of safety and literature. Many operators tend to ignore safety when operating paper cutter equipment, resulting in unnecessary losses. So what are the factors that affect the safe use of paper cutter products?

1.brakes. In order to save money, many manufacturers adopt the principle of circuit braking, that is, the upper and lower limit sensors cut off the power supply of the cutter motor to brake. This kind of device may cause "slippery knife" in the case of sudden power failure, loose socket, sensor failure, etc. extremely dangerous situation. In order to prevent this from happening, it is necessary to use a motor assembly with a mechanical brake device, so that no matter what circuit failure occurs, the motor is locked to avoid accidents.

2. Double button operation principle. This requires two buttons to be pressed at the same time, otherwise the cutter motor will not act, which can ensure the absolute safety of single-person operation.

3. In the actual use process, two people often cooperate to operate, so the situation becomes very dangerous, which requires the paper cutter to be equipped with front and rear safety covers. When the safety cover is opened, the motor will not operate to ensure safety.

4. The above are the safety factors that affect the use process. Then, when replacing the blade during maintenance and maintenance, use the blade holder to ensure that the blade edge is closed, which not only ensures the safety of people, but also ensures that the blade edge is not damaged.

The development and evolution of the paper cutter

5. In addition, the removed blade must not be put aside at will to avoid hurting people.

Only by operating the paper cutter products safely can the safety factor of the paper cutter be improved. Generally speaking, the use of paper cutters must develop good habits, so as to ensure the safety of the equipment.