Linear vibrating screen is generally composed of vibrator, screen box, support or suspension device, transmission device and other parts, and is mainly used in mining, coal, smelting, building materials and other industries. The working conditions of the linear vibrating screen are relatively harsh, and various failures often occur during operation. In response to these problems, the vibrating screen manufacturer gave us the following detailed explanations on the key points of operation and maintenance of the main components of the linear vibrating screen.
1. Adjustment of the eccentric block of the exciter
1) The size of the exciting force is closely related to the movement of the screen machine. There are 8 adjustment holes between the main block and the counterweight block of the eccentric block,which are equally divided by 15°, so it can be adjusted according to 8 positions at different angles. After being adjusted to different positions, the centrifugal force changes, and the vibration amplitude of the screen machine is changed accordingly.
When adjusting, each vibrator needs to be adjusted synchronously. If the adjustment position is different, the exciting force generated is different, and the material on the screen surface will jump irregularly. Therefore, correct adjustments must be made, especially when the exciter is replaced. When using the vibrator, the position of the adjustment hole must be consistent.
2) Inspection after adjustment, it is required that the two symmetrical points on both sides of the screen have the same amplitude and direction. If there is a slight difference in the amplitude of the two sides of the screen machine, no more than 0.5mm is allowed, because the movement track of the material is related to the uniformity of the material on the screen surface, and it is necessary to adjust the distribution of the incoming material in time.
The vibration exciters on both sides of the screen machine are connected by universal couplings. When replacing them, attention should be paid to the straightness of the joint surface of the universal couplings. The universal coupling has been dynamically balanced before leaving the factory, and the straightness of the coupling is directly related to the vibration amplitude of the screen machine.
When replacing, use the method of natural sagging of the eccentric block of the exciter, and then connect and fix the universal coupling with the coupling of the exciter. The difference in screw hole position is adjusted by adjusting the position of the spline. One thing to note is that the length dimension of the coupling and the length dimension of the spline should be selected reasonably to avoid insufficient coupling length or spline jamming.
3. Rubber buffer spring
Each rubber buffer spring can be used for about 15 to 20 months, and the size varies with the model of the screen machine. The temperature of the equipment cannot exceed 45°C when it is running. When replacing the rubber spring, attention should be paid to the elastic coefficient, that is, the height of the rubber spring at the inlet of the screen machine is similar to that of the outlet, so that the buffer rubber spring can be used reasonably and not easily damaged.
Also, when replacing the rubber springs, it should be noted that the rubber springs on the front and rear parallel lines should be replaced at the same time to avoid amplitude changes due to inconsistent aging of the rubber springs.
4. Support screen side
When a crack is found, it cannot be repaired simply by welding. Instead, it should be drilled and covered with a layer of steel plate, and fixed with screws. The main reason is that the stress and material of the screen side will change due to local heating during welding, making it more fragile.
5. Fastening of bolts
The connecting screws of each part are easy to loose due to long-term vibration, and must be inspected after the shutdown. The screws used should be high-strength bolts and high-strength locknuts, and should be coated with anti-loosening liquid. Anti-loosening disc springs should also be used for reinforcement for better results. In order to prevent the wear of the sieve plate bolts, polyurethane rubber sleeves can be used to cover the easy-wear parts of the bolts to avoid contact and wear with the material.
6. Screen support beam
The seamless steel pipe is used as the beam, and the dovetail groove slideway of the fixed screen plate is welded on it, and the round flanges welded at both ends are connected with the screen side by high-strength bolts. The beam needs to be annealed in the later stage of processing to eliminate internal stress and improve the strength of the beam and the screen. machine life. The crossbeam of the screen machine must be inspected after each shutdown, focusing on checking whether the support beam of the screen machine is severely worn and aged, and whether there is any damage such as cracks.
7. Sieve plate
The material of the sieve surface of the sieve plate used in the screen machine of some mineral processing plants is stainless steel 1Cr18Ni9Ti. Although the input cost is high, the use effect is better, especially in terms of abrasion resistance. At the entrance of the sieve machine, a blind sieve plate bonded with stainless steel and polyurethane is used, which has high strength.
The wavy and striped screens are used in raw material classification. The wavy screen has better penetration rate and is not easy to be blocked, but the disadvantage is that the screen bars are easily broken by large pieces of raw coal, so that large particles enter the next-level system. Repairs or replacements must be carried out promptly after each shutdown.
8. Additional facilities of the screening machine
1) The screening effect of the sieve machine is related to the thickness of the material on the screen surface and the distribution on the screen surface, so a material distribution plate that can adjust the angle can be installed at the feed port of the screen machine, according to the particle size of the raw coal and the feed material The amount of adjustment angle is used to adjust the uniformity of the material on the screen surface.
2) Install several water spray pipes above the sieve surface of the sieve machine, and use the pressure of water to improve the sieving rate and grading effect of the classification, and remove the impurities attached to the coal. The use of pressurized water on the media removal screen can improve the media removal effect and significantly reduce the consumption of media.
9. Screen lubrication
1) Lubrication of the exciter
Due to the high-speed rotation of the vibration exciter of the screen machine, axial deviation and torsion effect will occur during the operation, so the lubrication of the vibration exciter is particularly important for the maintenance of the screen machine. According to the running time, it is generally oiled once a week, and the amount of oil added is generally 300-600mL. Use 2# lithium base grease in winter and 3# lithium base grease in summer.
Since many equipments are still lubricated with calcium-based grease, you must pay attention to distinguishing when lubricating the exciter of the screen machine. The exciter cannot use calcium-based grease, otherwise the exciter will heat up and lock up during operation, resulting in accidents . Generally, the exciter is used for about three months, and the inside of the exciter is cleaned with an oil pump, and lubricating grease is added after cleaning.
2) Lubrication of the coupling
Since the coupling is splined, the vibration exciter produces shaft strings during operation, and the splines need to be well lubricated. Generally, oil is injected every 1200 hours of operation.
The above is a detailed explanation of the operation of the common components of the linear vibrating screen. Because of its high efficiency, low energy consumption, low noise, and stable work, the linear vibrating screen is widely used in the process of automatic operation of the assembly line. Because of the structure of double motors, the driving force is relatively large, the output is relatively high, and its screening efficiency is also relatively high, so the linear vibrating screen is the most efficient among all screening equipment, and its application is relatively wide.