Double roll crusher is widely used in mining, metallurgy, building materials, chemical industry and many other fields. From the preliminary crushing of various types of ores in mining, for subsequent beneficiation, refining and other processes to provide the appropriate size of raw materials, to the building materials industry, limestone, shale and other materials for the production of cement, bricks and other basic building materials, double roller crusher plays a key role. It is like an important link in the chain of industrial production, connecting the raw material in its original form with the qualified materials needed for production, and guaranteeing the smooth progress of each production link.

The double roll crusher crushes the material into the required size by applying squeezing force and shearing force to the material entering between the two relatively rotating rolls. This unique working principle makes it show good adaptability and high efficiency when dealing with materials of different hardness, humidity and particle size. This article brings you an in-depth understanding of the operating points and maintenance strategy of double roll crusher.

一.Basic knowledge of double roll crusher

The working principle of Double Roll Crusher is based on the crushing of materials by squeezing and friction between two relatively rotating rollers. When the material enters the crusher from the inlet, it is gradually brought into the gap between the two rollers by its own gravity and the friction force on the surface of the rollers. With the continuous rotation of the rollers, the squeezing pressure on the material gradually increases. Under the action of strong extrusion pressure, the internal structure of the material is destroyed, producing cracks and gradually broken.

At the same time, the friction between the roller surface and the material also plays an auxiliary role in the crushing of the material. This friction not only helps the material to move towards the crushing area, but also shears and grinds the material to a certain extent, so that the size of the crushed material is more uniform. For some brittle materials, such as limestone, shale, etc., it is easier to be crushed into smaller particles under the joint action of squeezing force and friction. When the material is crushed to less than the gap between the two rollers, it will be discharged from the discharge port, completing the whole crushing process. By adjusting the gap between the two rollers, the particle size of the crushed material can be precisely controlled to meet the needs of different production processes.

二.Double roll crusher operation guide

1.Preparatory work

Equipment Inspection: Firstly, check whether the connection of the various parts of the equipment is stable, and whether there is any loosening of the various bolts and nuts, especially the connection parts of the key parts such as rollers, transmission devices, and frames. Tighten the bolts by tools such as spanners to ensure the reliability of the connection. Secondly, check whether the lubrication system is normal, whether the amount of lubricant is sufficient, whether the oil quality is good, and whether the oil circuit is smooth. At the same time, check whether there is any abnormality in the electrical system, including the motor, control cabinet, wires and cables, etc., to see whether there is any leakage, short-circuit, loose wiring and other problems, to ensure the safety and reliability of the electrical system.

Material pre-treatment: In order to ensure the normal operation and crushing effect of the double roller crusher, it is necessary to pre-treat the material. First of all, the particle size of the material should be strictly controlled to avoid oversized material entering the crusher. The materials can be pre-screened by vibrating screen, grizzly screen and other equipment to separate the large materials whose particle size does not meet the requirements for further crushing or processing. Secondly, it is necessary to remove the metal impurities in the material, such as iron pieces, iron nails and so on. Metal impurities have high hardness and are difficult to be crushed, and after entering the crusher, they will cause serious scratches and abrasion on the surface of the rollers, reducing the service life of the rollers.

2.Start-up and operation

Start-up process: first of all, start-up with no load, i.e., start the motor with no material in the equipment. Before starting, carry out the disc operation first, rotate the roller by hand, check whether there is any stagnation phenomenon, and make sure that the roller can rotate freely. After confirming that there is no abnormality, press the start button to start the motor. In the process of starting the motor, pay close attention to the starting current, speed and other parameters of the motor, and observe the operating status of the equipment, whether there is any abnormal vibration, sound and so on. If abnormalities are found, the start should be stopped immediately, identify the cause and remove the fault before restarting. After the motor reaches the normal speed, then gradually load the material, slowly increase the amount of feed, so that the equipment gradually enter the normal working state.

Operation monitoring: During the operation of the double roller crusher, it is necessary to monitor the operation status of the equipment in real time, and find and deal with the abnormal situation in time, so as to ensure the safe and stable operation of the equipment and the smooth progress of the production. It is necessary to pay close attention to the temperature changes of the equipment, including the temperature of bearings, motors, rollers and other components. Excessive temperature may be caused by poor lubrication, overloading, equipment failure, etc., which can lead to component damage, equipment performance degradation or even cause safety accidents. The temperature of each component can be monitored in real time by installing temperature sensors and setting the temperature alarm value, so that when the temperature exceeds the alarm value, the alarm will be issued in time and corresponding measures will be taken to deal with the situation, such as shutting down the machine for inspection, adding lubricant, and adjusting the amount of feeding material. Secondly, pay attention to the vibration of the equipment, the normal operation of the equipment vibration amplitude is small and stable.

3.Shutdown operation

Normal shutdown: When the double-roll crusher needs normal shutdown, it should stop feeding first, let the equipment continue to run for a period of time, and finish all the residual materials in the equipment. This can avoid the accumulation of materials in the equipment, which will affect the next startup and the normal operation of the equipment. After stopping feeding, pay close attention to the operation of the equipment and observe whether the material is completely discharged. When it is confirmed that the material in the equipment has been fully processed, then turn off the motor of the equipment. After turning off the motor, the inertia of the equipment will make the roller continue to rotate for a period of time, during this period, do not carry out any operation on the equipment to avoid danger. After the roller completely stops rotating, then shut down the other ancillary equipment of the equipment, such as lubrication system, cooling system, etc.. Finally, clean up and inspect the equipment, clean up the materials, dust and other debris on the surface of the equipment and around it, and check whether the parts of the equipment are damaged, loose, etc., so as to prepare for the next use.

四.Double roll crusher maintenance points

1.Routine maintenance

Cleaning and maintenance: Regularly clean the dust and materials on the surface and inside of the equipment to keep the equipment clean is an important part of the daily maintenance of the double-roll crusher. When cleaning the surface of the equipment, use tools such as clean rags, brooms or hoovers to remove dust and debris from the surface. For cleaning the inside of the equipment, special attention should be paid to avoid the accumulation of materials in the crushing chamber, transmission parts and other parts. You can open the observation window or access door after the equipment stops, and use compressed air, brushes and other tools to clean up. Pay attention to safety when cleaning to avoid damage to the equipment. At the same time, it is also necessary to regularly clean the inlet and outlet of the equipment to prevent material blockage and ensure the normal entry and exit of materials .

Lubrication management: According to the requirements of the equipment, add or replace the lubricant regularly to ensure that the components are well lubricated. Good lubrication can reduce the friction between parts, reduce wear and prolong the service life of the equipment, and also reduce the noise and energy consumption of the equipment. When adding or replacing lubricant, operate in strict accordance with the requirements of the equipment instruction manual, and select the appropriate lubricant varieties and specifications. Different parts may require the use of different types of lubricants.

2.Regular maintenance

Component inspection: checking the wear and tear of rollers, transmission devices, bearings and other components, and timely replacement of badly worn components are the key contents of regular maintenance of double-roll crusher. As a part directly involved in material crushing, the rollers are susceptible to abrasion, scratches and spalling as their surfaces are subject to strong friction and impact of materials in the long-term working process. When the rollers are worn to a certain degree, it will affect the crushing effect and the uniformity of product size, at this time it is necessary to replace the rollers in time. Belts, chains, gears and other components in the transmission device, in the process of transmitting power will also be worn, such as belt slack, chain elongation, gear tooth wear, etc. These problems will lead to transmission efficiency, equipment vibration increases, and even slippage, off the chain and other faults, affecting the normal operation of the equipment. Therefore, it is necessary to regularly check the components of the transmission device and make timely adjustment, replacement or repair according to the wear and tear. Bearing is an important part to support the rotation of roller and transmission parts, its working conditions are relatively harsh, easy to be affected by high temperature, high pressure, wear and corrosion and other factors. Regularly check the wear of the bearings, the size of the clearance, the lubrication condition and temperature changes, etc. If you find serious wear of the bearings, excessive clearance, high temperature or abnormal sound, etc., the bearings should be replaced in a timely manner to ensure the smooth operation of the equipment .

3.Replacement of wearing parts

Roller replacement: When the roller is worn to a certain degree and cannot meet the crushing requirements, it needs to be replaced. When replacing the rollers, first of all, do a good job of safety measures to ensure that the equipment stops and cuts off the power supply to prevent accidental startup. Then, the lubrication pump is depressurised, the belt head is cleaned of pumice and other debris, and the parts related to the rollers are removed, such as inlet guards, outlet parts, drive connections, etc. The lifting process needs to be directed by a special person, and the lifting operating procedures should be strictly adhered to. When dismantling the old roller, if it is difficult to remove the liner, it can be cut by gas welding. When installing the new roller, make sure that the installation position of the roller is accurate, the connection with the transmission device is firm, and the gap between the components meets the requirements. After the installation is completed, carry out trial operation, no-load running for a period of time, check whether the equipment has abnormal noise, vibration, temperature is too high and so on, to confirm that everything is normal, and then gradually loaded with materials into production.

Other wearing parts: Besides the rollers, the seals and drive belt of the double roller crusher are also wearing parts, which need to be checked and replaced regularly. The function of seals is to prevent dust and materials from entering into the equipment, and to protect bearings and transmission parts from pollution and damage. If the seals are worn or aging, the sealing performance decreases, which will lead to dust and materials entering the inside of the equipment, accelerating the wear and tear of the parts and affecting the normal operation of the equipment. Therefore, it is necessary to check the wear and tear of the seals regularly, and once the seals are found to be aging, deformed, ruptured or with poor sealing effect, they should be replaced in a timely manner.

As an indispensable equipment in industrial production, double roll crusher, in terms of operation, rigorous and meticulous preparatory work is the premise of normal startup and operation of the equipment, strictly follow the startup process and operation monitoring points, as well as the correct implementation of the shutdown operation, each link is closely linked to each other, and the negligence of any one of the links may lead to equipment failures and safety accidents. In terms of maintenance, cleaning and lubrication management in routine maintenance, component inspection and adjustment and calibration in regular maintenance, as well as timely replacement of wearing parts, these measures can effectively prolong the service life of the equipment to maintain the good performance of the equipment.