The spiral screener is a new type of screening equipment that is suitable for coal screening operations in coal mine preparation plants. It has good application effects and can improve production efficiency and increase economic benefits. The spiral classification screen is suitable for coal mining enterprises, coal preparation plants, and power plants. It is used for screening and classifying dry and wet coal. It has a high screening rate, wet sticky coal does not block the screen holes, fast advancement speed, and large processing capacity (larger than vibrating screen). 2 times), when used in power plants, fully enclosed products can better protect the production environment of the coal loading system.
The screen surface of the spiral screen is composed of a row of parallel spiral shafts. The screw is divided into two types: large lead right-hand thread and left-hand thread, each accounting for half of the screen surface.
Working principle of spiral screening machine, structural characteristics of spiral screening machine, spiral screening machine
Working principle of spiral screening machine
The spiral screening machine is composed of two or three sections of screening machines with the same structure connected in series. The screening units in each section are arranged in a ladder shape and can be interchanged. They are connected by a transition plate in the middle. Each section of the screening unit is composed of a frame, It consists of a transmission box, an electric motor, and a row of spiral rollers with left-hand threads and right-hand threads. The spiral roller is installed between the front support and the rear support, and the two supports are fixed on the frame. The rear end of the spiral roller is connected with a rigid coupling and a transmission box. A motor is installed on the screening machine frame, which drives the transmission device through a triangle belt, so that the spiral roller obtains power to rotate for screening operations. The tail ends of all spiral rollers are equipped with gears. The previous roller is transmitted from the gear to the next spiral roller through rolling bearings and intermediate gears. The transmission box is equipped with a spiral shaft that operates synchronously. In addition, in order to prevent the screen from overloading, an electromechanical safety protection device is installed to effectively ensure the safety. If three or more levels of units with different specifications are used for combination, a variety of screening products with different specifications can be obtained, thereby simplifying the screening process.
Structural features of spiral screening machine:
1. Wearing parts such as screen shafts and screen plates are easy to replace; the screen plates adopt plum blossom-shaped screen plates and are arranged in a staggered manner, which not only facilitates the transportation of coal materials, but also reduces the dead angle formed by adjacent screen shafts and avoids jamming. Suitable for bituminous coal, anthracite, lignite, coal gangue and other materials.
2. Each screen shaft is driven independently by a motor reducer, that is, each set of screen shafts is equipped with a set of driving devices; the reducer and the roller screen coupling are connected by an elastic pin coupling; any set of screen shafts When a fault occurs, the coal fired can be pushed by the previous screen shaft and continue to move forward over the faulty screen shaft, and the equipment can still operate. Each screen shaft rotates in the same direction and at the same speed and has overload capacity. Each rotating part rotates flexibly without jamming.
3. The screen shafts are reasonably arranged at multiple angles. The angle between the screen shaft and the horizontal is 15° in the entrance section of the equipment, and the angle between the screen shaft and the horizontal in the outlet section is 5°, so that the coal materials entering the equipment will be initially coarsely screened and then subjected to secondary screening. Sub-fine screen can effectively improve screening efficiency and prevent coal blockage.
4. There are wear-resistant lining plates on both sides of the equipment box to avoid direct contact between the material and the box body, greatly extending the service life of the equipment; and the wear-resistant lining plate and the box body are connected with bolts, making replacement easy.
5. There is a baffle switched by an electric (liquid) push rod at the entrance of the machine, which allows the coal material to directly enter the lower belt during maintenance of the roller screen without affecting the operation of the system; the coal baffle is placed at the feed inlet. Below, when the equipment is in working condition, the baffle is in the position of state I; when the coal particle size is ≤30mm and does not need to be screened or the equipment fails and the coal conveying line cannot be shut down, the electric (liquid) push rod can be started to rotate the coal baffle. At the position of state II, the coal flow can directly fall into the downstream conveyor belt. The baffle is made of wear-resistant steel plate and has a uniform distribution function, so that the coal material can be spread evenly on the entire screen surface to achieve a better screening effect.
6. The surface of the screen is fully processed to improve its surface smoothness to prevent coal sticking, and there is a heat-treated "blade"-shaped cleaning plate under the screen shaft, which can remove coal sticking on the sides and roots of the screen, effectively preventing coal blocking. happened.
7. The two ends of the screen shaft adopt a wear-resistant lining plate-wrapped disc structure, which completely solves the problem of large blocks stuck on both sides of the box and the screen, ensuring the normal operation of the equipment.
8. The output shaft end cover of the screen shaft is double sealed with a rubber sealing gasket and an O-shaped felt ring to ensure that the box is tight and does not leak coal powder; the bearing seat adopts a split type, and the bearings are lubricated with calcium-based grease instead of thin oil. , easy for maintenance and repair, the bearing seal is labyrinth sealed to ensure no grease leakage; the bearing temperature rise is generally not greater than 40°C, and the bearing temperature does not exceed 70°C.
9. The entire equipment is made of steel plates with a thickness δ ≥ 10mm to ensure that the box and base have sufficient rigidity; the welding surface is smooth and flat, without defects such as pores, slag inclusions, welding nodules, cracks, etc., and the main welds are still intact. Carry out flaw detection inspection.
10. Each screen shaft of the roller screen is equipped with mechanical and electrical dual protection. When the equipment is overloaded, the nylon safety pin of the coupling will be sheared to mechanically protect the reducer. In addition, when the screen shaft is blocked, When the motor rotates, the motor current becomes larger. Contact number +8613383841555 (same as WeChat) If it exceeds the critical value, an alarm signal will be sent out, thus providing electrical protection.
11. The roller screen adopts sequential start, that is, the first screen shaft at the outlet starts first, and then starts in sequence upwards, so that the equipment can be started with load when there is coal on the screen surface.
12. The screen shaft and screen plates have sufficient mechanical strength and rigidity, and can meet the requirements of starting operation under load.