1. Working principle of roller press
Roller presses operate on the principle of low-energy high-pressure material-bed comminution, applying individual-particle crushing collectively to a bed of particles. Compression of brittle material in the high-pressure zone rapidly reduces particle size. Fine powder <0.08mm accounts for 20%–30%, and material <2mm accounts for more than 70%. Numerous cracks remain on the surfaces of all compressed material, markedly improving grindability. This substantially reduces the energy required for grinding in the next process, delivering major gains in output and energy savings.
Key points:
1, The roller press consists of two rollers with equal speed and relatively slow rotation. One roller is fixed and the other roller can move in the horizontal direction to control the gap between the two rollers.
2 relies on the hydraulic system to act on the movable roller, forming a high pressure between the two rollers. The pressure range is 50 ~ 300 MPa.
3 and roller press are designed based on the mechanism of material bed crushing. The prerequisite for material bed crushing is that there should be a dense layer of material between the double rollers.
4, after the material passes through the roller press: the particle size decreases; the particle cracks increase, and the grindability improves.
2. Roller press structure
3. Inspection and maintenance of roller press
1, inspection and maintenance of mechanical parts
1) Inspection and maintenance of the shafting part
The 4 bearings of the grinding roller spindle are double row tapered roller bearings with a tapered inner hole. During the production process, the grinding roller bearing will move outward and become loose after being stressed. Therefore, during the production process and after shutdown, be sure to check whether the fastening bolts of the inner and outer ring end covers of the bearing are loose.
Inspection: (1) Visually check whether the hexagonal head of the bolt is loose. If you see obvious gaps in the spring washers, you can conclude that the bolt is loose; (2) Use a suitable wrench to tighten the hexagonal head of the bolt to check whether the bolt is loose;
Maintenance: Tighten all bolts of the inner and outer ring glands of 4 bearings.
2) Inspection of water cooling system
The water cooling system is used to reduce the operating temperature of the spindle and bearings. During the start-up process of each shift, the first thing to do is to check whether there is any water leakage in the water cooling system. If there is excessive water leakage, it must be reported to the superior and cannot be disassembled by oneself. The second thing is to check the temperature difference between the inlet and outlet water to determine the cooling effect.
3) Main rack inspection
The main frame is the foundation of the entire extrusion crusher, and it bears the extrusion and crushing force. Check all fastening bolts and nuts every shift to see if they are loose. You can check with the clearance of the spring pad or with a wrench. Check whether the positioning pin is loose and moved out. If it is moved out, drive it into place in time.
4) Inspection of feeding device and roller surface
After each shutdown, check whether the feed inlet, support frame, side baffles and side baffle tightening devices are abnormally damaged, whether the connecting bolts are loose or severely worn, whether the gap between the side baffles and the end face of the grinding roller is too large (exceeding 3mm), and whether the adjustment device still works. Check the wear of the "diamond" pattern on the roller surface. If there is local peeling or excessive wear (the wear height of the wear-resistant layer reaches 7mm), repair welding in time.
The above inspections can only be carried out by entering the roller press through the inspection door.
5) Inspection of the transmission part
After stopping the machine, check whether the bolts of the shrink sleeve coupling are loose, visually or with a wrench.
After stopping the machine, check whether all the connecting bolts between the reducer and the torque support plate are loose. Check visually or with a wrench.
Check whether the connecting bolts of the universal drive shaft are loose. If they are loose, stop the machine in time.
Check whether the connecting bolts of the torque support plate are tight and whether the spherical bearing is abnormal.
2, inspection and maintenance of hydraulic system
1) The appearance of some equipment in the hydraulic system must be kept clean.
2) Check each oil pipe interface or joint to see if there is oil dripping. If so, tighten it in time.
3) Check whether the left and right pressure gauge pointers of the pressure maintaining system change (swing) following the movement of the moving roller. If there is no change, check whether the pressure gauge is damaged.
4) Check whether the automatic pressure relief is normal. At this stage, the pressure holding setting is 10.5MPa. If the pressure gauge pointer exceeds this pressure, the pressure will be automatically relieved. If there is no such action, feedback must be given to the superior in time for prompt processing.
5) Central control personnel should promptly check whether the shutdown is protected in time when the pressure exceeds 1 2MPa.
6) Check whether the pressure increase and decrease is working normally. The oil pump will automatically pressurize when the system pressure is lower than 7.5MPa, and automatically stop pressurizing when the system pressure reaches 8.5MPa. If the pressure increase and decrease is not working properly, please provide timely feedback and deal with it.
7) Check whether the hydraulic oil level at the oil station is normal. If the oil level is too low, add 46# anti-wear hydraulic oil in time.
8) Check whether the sound of the 2 oil pump is normal when it is working and whether the pressure gauge indication is normal.
9) Each time the machine is shut down, it is necessary to detect whether the pressure of the 4 accumulator is within the normal value of 5.5~6.0 MPa. If the pressure is too low, add nitrogen in time.
10) Frequently check whether the movement of the moving roller is flexible and whether there are changes in the hydraulic system.
3, inspection and maintenance of lubrication system
1) Check the main reducer lubricating oil flow and oil color to see if it is normal. Check whether the temperature difference between the inlet and outlet oil pipes of the cooler is normal. If it is abnormal, find out the cause and deal with it in time. Check whether the oil level of the main reducer is in the middle of the lens. If the oil is low, add it in time. Check the oil pipe joints for oil leakage. If there is oil leakage, deal with it in time.
2) Check whether the inlet and outlet water temperature of the water cooling system is normal. Generally, the inlet water temperature is lower than the outlet water temperature, which can be felt by touching it with your hands. If it is abnormal, it should be dealt with in time.
3) The central controller should frequently check the temperature of the main reducer bearings. The system temperature is set to alarm at 70 and trip and stop at 75.
4) Check whether the dry oil pump is operating normally and whether the oil quality has deteriorated.
(Source: cement information)