This coal plant is a mine type steam coal preparation plant with an annual design capacity of 1.5Mt/a. After secondary screening of raw coal, the material under the screen is sold directly to the power plant as a product. The material on the screen of secondary screening and the crushed product of the material on the screen of primary screening together enter the jigging coal separation. Here secondary screening plays a crucial role. With the improvement of mine production capacity, our factory now handles 2.6 million tons of raw coal annually. The secondary screening machine adopts the common F-type coal banana screen, which has good use effect.
2.1 Structural coal banana screen is composed of screen box, vibrator, transmission device and supporting device: screen box is composed of screen frame, screen surface and tensioning device, etc. Screen frame is a space metal structure with riveted connection, and the lower beam group is arranged in line shape and divided into 5 sections. The vibrator adopts two box type vibrator, one of the drive shaft of the vibrator and the transmission device is connected by a universal coupling, the other end of the drive shaft of the vibrator and the other end of the relative shaft of the vibrator with a soft connection. The transmission device is composed of a drive shaft, a bearing and a bearing seat with a belt wheel. The supporting device is connected with the bottom frame by 12 groups of steel spring supporting devices.
2.2 Working Principle
For the ordinary linear vibrating screen, the thickness of the material layer on the screen surface is gradually decreasing from the feeding end to the discharging end, the speed of the material on the screen surface is basically the same, and the screen surface to give the acceleration of the material is smaller, the material on the screen surface layering effect is poor, resulting in low screening efficiency. XF type coal banana screen application of equal thickness screening principle, the screen surface into a concave arc, the overall shape is similar to fruit banana, starting from the inlet, screen surface dip Angle decreases in turn, the last section of the discharge screen surface is basically about 10°, the maximum dip Angle is 36°, forming a smooth transition concave arc. Material from the inlet rapidly sliding stratification, material layer quickly thinning, into the next section of the screen surface, due to the screen surface dip Angle in decreasing, the speed of movement of the material is also gradually slowed down, the material layer basically each section is the same thickness, then the material in the rapid operation process to get effective screening, because large material quickly through the steep slope, this earlier stratification, The fine particles get closer to the screen surface faster, and can pass through the screen gap relatively unhindered, so the banana-shaped linear vibrating screen has a very high screening efficiency and 1.52 times higher production capacity than the same type of traditional grading screen.
The main technical characteristics of 3coal banana screen (1) the production capacity of the unit area is large, the material content under the screen accounts for more than 50%, compared with the same type of vibrating screen, improve the production capacity of about 1.5~2 times (2) the screen plate adopts the bar stainless steel screen, has the characteristics of high strength, wear resistance and high opening rate, The whole screen surface is composed of 25 pieces of screen plate, according to the actual needs of the production of flexible adjustment screen size, bar bar sieve sieve with vibration and rotation, making the material is not easy to plug, greatly improve the screening efficiency. (3) The screen frame and each member (rectangular support beam) reasonable arrangement, uniform force, with high reliability, long service life. Beautiful shape, simple structure, easy to maintain, occupy relatively small space. (4) The unique structure of the side plate, all adopt cold riveting connection, reinforcement according to the distribution of stress point configuration, no weld, no stress concentration, no deformation and tear, greater strength, higher reliability. (5) Advanced vibration parameters (K= 4.0-4.87), stable performance, stable operation, low noise (80-85dB). (6) The vibrator adopts new "eccentric block external integral box type" structure vibrator, bevel gear drive, safe and reliable, lubrication, sealing superior, maintenance, replacement, convenient amplitude adjustment. (7) The feed box and discharge port are equipped with wear-resistant and replaceable lining plates to protect the impact and wear of the beam in the blind hole area. (8) The blind plate of the feeding box and the rear screen surface form two angles to buffer the impact of large materials on the screen surface and slow down the speed of the material, and play the role of distributing materials to the feeder. (9) The transmission system is simple. The transmission system is driven by a 45KW motor through the triangle belt to the universal connecting shaft, and the connecting wheel of the universal connecting shaft is connected with the shaker, so as to eliminate the connection length and axis Angle changes caused by the vibration of the vibrating screen.
This coal preparing plant installed and used a ZXF3055/5 type coal banana screen in 2006, replacing the original double-jointed vibrating screen, to solve the problem of resonance when the original vibrating screen works. The application shows that XF type coal banana screen runs smoothly and reliably, has the characteristics of small failure rate, small vibration, low noise, large processing capacity and high screening efficiency. According to the quality changes of raw coal in the coal preparation plant and the needs of the market for product requirements, the lower limit of separation particle size can be adjusted between 10~20m by replacing the sieve plate, which can fully meet the screening requirements of the coal preparation plant.
