The belt conveyor is the main equipment for coal transportation in thermal power plants. It is relayed through various belt conveyors to form the entire chain coal transportation system from the coal storage yard to the coal bunker. Belt deviation is a common fault in the coal conveying system. It refers to the phenomenon that the belt deviates from the center line of the belt conveyor and deflects to one side under the action of lateral force during operation. The deviation of the coal conveying belt will affect the normal operation of the entire coal conveying system, and its hazards include scattered coal, reduced belt output, belt damage, edge damage, reduced service life, and over-limit shutdown. In severe cases, it may even cause major accidents such as coal flow, blockage, and belt tearing. Because the coal transportation system is a chain structure, once a problem occurs in a certain section, the entire line will be shut down, which will seriously affect the production and operation of the power plant.

Causes of deviation of coal conveyor belt

a. The axis of the belt head and tail drum is not perpendicular to the center line of the belt conveyor. This situation may be due to installation problems or improper adjustments, or it may be caused by the loosening of the fixing bolts and limit adjustment bolts of the roller bearing seat during operation. The axis of the drum is not perpendicular to the center line of the belt conveyor, which can directly cause the belt sides to loosen and tighten, and the longitudinal tension is different.

b. There are too many failures of the roller on the same side of the belt conveyor. Within a certain length of the belt conveyor, there are too many faulty rollers on the same side. For example, the roller bearing is damaged or the roller does not rotate, the roller bracket is damaged or deformed, etc., which increases the resistance between the belt and the roller or even slips. The side friction and side force increase. It not only causes the belt to deviate, but also seriously damages the belt. This type of failure is more common in operation sites.

c. The coal drop point deviates from the center line of the conveyor. Due to the large difference in coal type, particle size and humidity, the reserves also fluctuate, causing the coal drop point to deviate from the belt conveyor's longitudinal centerline, and the impact force is directly converted into belt lateral force, and at the same time, an eccentric load is formed, and even the entire belt Wandering across the board.

d. The joint of the coal conveying belt is not correct. The seam of the belt vulcanized joint is not perpendicular to its longitudinal centerline, which directly leads to uneven tightness on both sides of the belt, causing lateral force and deviation during operation.

e. Other comprehensive factors. Belt deviation is sometimes caused by individual or combined factors at individual points. For example, individual rollers, coal deposits on rollers, rubber lining and surface damage, poor working conditions of cleaners, and irregular angles and positions, etc., can cause unequal longitudinal tension on both sides of the belt and cause deviation.

Due to structural reasons, after the deviation belt is reset, the corner of the adjustable center roller group cannot be adjusted back in time, causing the belt to circulate left and right. This is a drawback of some deviation correction devices. In addition, the correction device is relatively complicated, high in cost, poor on-site operating conditions, and strong corrosiveness of coal powder, resulting in component failures and idler deflection failures. The forward-inclined idler group is the same as the ordinary trough-shaped idler group, which is fixed on the conveyor frame by the idler bracket. The two side idlers are inclined 2°-3° to the belt running direction, and the lateral force can restrict the belt running Partial. However, due to the small forward tilt angle and limited lateral force, it needs to be installed at intervals of 3:7 ratio. The forward tilting roller runs stably and reliably, but the forward tilt of the roller can increase the running resistance, which should be taken into consideration when using it.

Take comprehensive measures

There are advantages and disadvantages to the use of correction devices. Based on years of experience, we should not only focus on how to correct deviations, but take the initiative to prevent belt deviations. According to the actual conditions and equipment conditions of each section of coal conveying, comprehensive measures should be taken for the cause of belt deviation to find and eliminate hidden dangers as soon as possible, and control from the source is often effective.

a. Arrange special personnel to be responsible for the head and tail rollers of each section of the belt conveyor, and combine regular inspections with uninterrupted inspections to ensure the verticality of the roller axis and the longitudinal centerline of the conveyor to ensure that the roller bearing seat is fixed and the limit adjustment bolts are tight. Solid and reliable.

b. The overhaul and maintenance of the belt conveyor roller is managed by sections, problems are found in time, dealt with in time, sufficient spare parts are reserved, random replacement and regular replacement are combined to ensure trouble-free operation of the roller as far as possible. The adjustment baffle of the important part of the coal falling pipe is modified, the shaft sleeve is changed to a fully sealed bearing, and the adjustment part is made of 304 stainless steel, so that the adjustment baffle can rotate flexibly and adjust freely. At the same time, pay attention to the maintenance and repair of other coal drop point adjustment baffles to ensure that each coal drop point can be controlled and adjusted at any time.

When installing the roller bearing seat, pay attention to matching with the roller, and meet the requirements at high temperature and high speed. Therefore, the following two points should be considered when considering its cooperation:

1. What is the change in size and hardness when it rises from normal temperature to high temperature.

2. A series of mechanical changes and shape changes caused by centrifugal force at high speeds.

All in all, under the conditions of high speed and high temperature, it is necessary to maintain the precision and working performance of the stamping bearing seat in cooperation with the roller, and this is indeed difficult. Therefore, in order to ensure that the raceway deformation of the stamped bearing seat after installation is small, the amount of interference of the interference fit must not be too large, and the centrifugal force at high speed and the thermal expansion caused by high temperature can also offset it. Back pressure on the surface. If the mating surface of the stamped bearing housing is loose, then the interference should be carefully calculated under the premise of considering the above two situations, and the interference at room temperature and normal speed can be invalid for the stamped bearing housing. .

The wear of the bearing housing of stamping rollers and the wear of the bearing housing are two common problems. On-site, the method of avoiding machining saves a lot of downtime for the company and creates a huge production value. Traditional methods generally use machining after surfacing, and surfacing will cause the surface of the component to reach a high temperature, causing deformation or cracking of the component, and obtaining the size through machining will greatly extend the downtime. However, the use of Fuschlan polymer composite material for the site has no thermal influence, and the thickness is not limited. The product has the characteristics of the product and the retreat that the metal material does not have. It ensures 100% contact and coordination of the parts and reduces the impact and vibration of the equipment. , To avoid the possibility of wear.

Stamped bearing housing is a more representative stamped bearing. It has a wide range of uses and can accept radial load and bidirectional axial load; it is suitable for high-speed rotation and occasions requiring low noise and low vibration; with steel plate dust cover or rubber sealing ring Sealed bearings are pre-filled with appropriate grease; bearings with a stop ring or flange on the outer ring are simple to locate in the axial direction and facilitate installation in the housing; bearings with larger loads have the same dimensions as standard bearings, but There is a filling groove in the inner and outer ring, which increases the number of balls and increases the extra load.

The device of stamping bearing seat can effectively reduce the bearing pressure of the bearing, and the stamping bearing seat is a supporting part of the bearing. So, what are the common functions of stamped bearing housings?

1. The stamped bearing housing has low friction resistance, low power consumption and improved mechanical efficiency.

2. The stamped bearing seat has high precision, fast speed, but low wear and long service life.

3. The dimensions of the stamped bearing housings are unified, interchangeable, easy to disassemble, and easy to maintain.

Fourth, the quality of stamping bearing housing is stable and reliable, and the production efficiency is high, which can be used for mass production.

5. The stamped bearing housing has a compact layout, light weight and reduced axial size.

6. Stamped bearing housings generally have the function of active centering.