is a kind of special equipment for handling materials with strong impact and relatively large load. It has the advantages of slow running speed, strong impact resistance, strong continuous work and low maintenance cost.
Power refers to the amount of work done by an object in unit time, that is, power is a physical quantity describing the speed at which work is done. There is a certain amount of work, and the shorter the time, the greater the power value. The formula for power is power = work/time. A physical quantity representing the speed at which work is done. The work done in unit time is called power and is expressed in terms of Pesos power is equal to the scalar product of the acting force and the velocity at the point where the object is acting.
In large - scale mining, the transport of materials is mainly divided into belt transport and apron feeder transport. Because the belt is easy to be cut by ore and stone, the service life is short, the average is one month. Sometimes three to five days to replace, each change needs to stop production for half a day to a day, resulting in the suspension of maintenance. The feeding speed of belt conveyor is too fast, the ore bin is often emptied, the material is easy to break the roller, so that the damage of belt conveyor is intensified. In conclusion, it can be seen that the maintenance of the belt conveyor is large and valiant. Apron feeder is a steel structure with 16Mn wear-resistant contact surface with materials, which is not easy to be worn and cut by materials. Its operation characteristics are low speed and heavy load, with strong compressive resistance. To sum up, apron feeder is generally selected under the silo above the vibrating screen and crusher. Then how to correctly choose the power of the driving motor of the apron feeder according to the known conditions, so that the power can be effectively utilized, and the power should be sufficient and not wasted. The power definition and calculation method are described in detail and illustrated with examples
The various resistances of plate feed affect the mechanical selection of these powers
(1) Operation resistance of heavy-duty apron feeder
The operating resistance of heavy-duty apron feeders is divided into two categories according to the causes: friction and ramp resistance. The friction includes: the friction resistance caused by the dead weight of the moving parts of the apron feeder, the friction resistance caused by the positive pressure of materials, the friction resistance of transporting materials and apron, the friction resistance of the feeding device and additional resistance.
Friction resistance of moving parts
The frictional force of moving parts includes the frictional resistance of the upper and lower branch support wheel and the chain track groove plate in the supporting device. Although the upper and lower branch support wheel and chain rail groove plate are not uniformly distributed within the center distance. But in the calculation can be approximated as the uniform load in the range of center distance.
The friction resistance caused by the positive pressure of the material
The thickness of material on the groove plate is basically uniform. Then the positive pressure exerted by the weight of the material on the trough plate is even. The resulting pressure ultimately ACTS on the upper branch supporting idlers.
(3) The friction resistance of conveying materials and apron
The material flow between the groove plate and skirt plate will form a material flow with approximately rectangular cross section. It has side pressure on the skirt board, when the material is running with the groove board. Friction resistance will be generated between the material and the apron.
The friction resistance of the guide device
In general. Heavy-duty apron feeders
are installed below the silo, which exerts a certain pressure on the running parts. This creates frictional resistance. Also known as the resistance of the guide device.
The main pressure P acting on the apron feeder is related to the nature of the material, the depth of the material in the bin and the structural form of the bin. Usually according to the depth and hydraulic radius of the silo is divided into shallow silo and deep silo two cases. When the silo depth is greater than l0 hydraulic radius. For the deep bin, otherwise for the shallow bindles materials have certain fluid properties. At the same time due to the internal friction between the loose materials. When the material is piled up in the silo, the pressure of the loose material to the outlet cannot be calculated completely according to the static pressure of the fluid. It is also not possible to calculate the weight of the loose material. It is necessary to calculate the difference between the depth and depth of the silo according to the height of the silo and the hydraulic radius of the loose material. In a relatively stationary material, the forces exerted on the material unit cancel each other out. Get rid of the counteracting forces. The material is mainly affected by the four forces shown in the figure. Gravity and support force are a pair of action and reaction, and traction and friction force are a pair of action and reaction.
According to the resistance and load the material and capacity to determine the power of apron feeder power, the power of choice is essential to the apron feeder, because too much power to choose corresponding facilities will also corresponding price is too high, utilization is insufficient, will cause the waste of resources, if the power choice is too small, can lead to related facilities cannot meet the needs of processing. So in the power of the choice must be reasonable and scientific selection, buy the appropriate apron feeder.