1. Working principle

Rotary kiln is the main equipment of cement production.

The raw meal powder is fed into the kiln barrel from the bottom of the high end of the kiln tail barrel. Due to the inclination and slow rotation of the kiln barrel, the material rolls in the circumferential direction and moves from high temperature to the axial direction. The composite motion of the low-end movement, the raw meal passes through the process of decomposition and sintering in the kiln, and after sintering the cement clinker, it is discharged from the bottom end of the kiln cylinder and enters the cooler.

The fuel is injected from the kiln head and burned in the kiln, and the heat emitted heats the raw meal, so that the raw meal is calcined into clinker. The chimney vents into the atmosphere.

2. Structural characteristics

Rotary kiln is mainly composed of kiln shell, transmission device, support device, blocking wheel device, kiln head sealing device, kiln tail sealing device, kiln head cover and so on.

1. The kiln barrel part

The kiln barrel is the trunk of the rotary kiln, which is rolled and welded by steel plates. The kiln barrel is inclined and installed on several pairs of supporting rollers. The bottom end of the kiln barrel is equipped with a high temperature and wear-resistant kiln mouth guard plate. A sleeve space is formed, and a special fan is provided to cool the kiln mouth. There are several rectangular belts along the length of the kiln shell, which bear the weight of all rotating parts such as the kiln shell, kiln lining, materials, etc., and transmit the weight to the supporting device. Adjust or replace according to the clearance after operation to obtain the best clearance. The backing plate can increase the rigidity of the kiln shell, avoid the wear of the kiln shell due to the relative sliding between the wheel belt and the kiln shell in the circumferential direction, and reduce the internal and external wear of the wheel belt. The effect of surface temperature difference.

2. Large ring gear device

A large ring gear is fixed near the end of the kiln barrel to transmit torque, and the large ring gear is connected to the kiln barrel through a tangential spring plate. There is enough space for heat dissipation between the cylinders, which can reduce the influence of the bending and deformation of the kiln cylinder on the meshing accuracy, and also has a certain shock absorption and buffering effect, which is beneficial to prolong the life of the kiln lining.

3. Transmission

⑴ Transmission type:

a. Single drive

The transmission system adopts single transmission, which is driven by a main transmission motor.

The main drive system is composed of the main motor, the main reducer pinion, etc. At the same time, a combined elastic coupling is used to improve the stability of the transmission. The tail of the main motor is equipped with a tachogenerator to provide power for the instrument that displays the kiln speed.

In order to ensure that the kiln can still be operated when the main power supply is interrupted, to prevent the bending and deformation of the kiln cylinder, and to facilitate the maintenance of the kiln, an auxiliary transmission device is provided. It consists of electric motor, reducer and so on. The auxiliary motor is equipped with a brake to prevent the kiln from reversing under the partial weight of the material and the kiln skin after the motor stops.

b. Double drive

The transmission system adopts dual transmissions, which are driven by two main transmission motors respectively. The synchronization of the two transmission systems is realized by adjusting the electrical equipment, so as to ensure the uniform force of the two systems. Stagger the configuration of the 1/2 week section.

⑵ motor

Except the small rotary kiln can use Z2 series small DC motor, the others all use ZSN4 DC motor specially for rotary kiln, which is a special product manufactured on the basis of Z4 series motor and according to the working conditions of the main drive of cement rotary kiln.

⑶ reducer

The reducer generally adopts the hard tooth surface reducer, which has advanced technology, small size and light weight.

⑷ Combined elastic coupling

A combined elastic coupling is used between the pinion device and the main reducer, which has good elasticity, can absorb part of the impact, and can compensate for large radial deviation and axial expansion.

4. Supporting device

The support device is an important part of the rotary kiln. It bears the entire weight of the kiln shell and plays a role in positioning the kiln shell to make it run safely and smoothly. The support device is a self-aligning sliding bearing structure. Compact and lightweight. And equipped with lubricating oil automatic heating and temperature control device and temperature measurement device, reliable operation and strong adaptability.

5. Blocking wheel device

According to its force and action principle, the retaining wheel can be divided into two types: mechanical retaining wheel and hydraulic retaining wheel.

The mechanical stop wheels are installed in pairs on both sides of the large ring gear adjacent to the wheel belt, and play the role of limiting the axial movement of the kiln cylinder.

hydraulic wheel

The hydraulic blocking wheel is arranged near the underside of the large ring gear adjacent to the belt. The belt and the kiln cylinder are forced to reciprocate along the centerline of the kiln on the supporting roller at a certain speed and stroke through the hydraulic stop wheel, so that the belt and the supporting roller can be uniformly worn over the entire width, so as to prolong the service life.

5. Kiln head sealing device

The kiln head sealing device adopts either SM type (graphite block type) kiln head sealing device or GP type (steel sheet type) kiln head sealing device to meet different working conditions and user needs:

The SM type kiln head sealing device adopts the graphite block radial contact type + labyrinth type sealing form, which can automatically compensate the deflection of the kiln cylinder during operation and the reciprocating movement along the axial direction during operation. Good sealing performance.

The GP type kiln head sealing device adopts the sealing form of steel sheet radial contact type, which can automatically compensate the deflection of the kiln cylinder during operation and the reciprocating movement along the axial direction during operation, and has good sealing performance.

7. Kiln tail sealing device

The QD kiln tail sealing device adopts the cylinder pressing end face contact type, the entire sealing ring is uniformly stressed and can eliminate the adverse effects caused by the installation and the deflection of the kiln shell. In addition, the grease is injected into the contact surface of the friction ring by the electric dry oil pump for lubrication, the friction resistance and wear are small, and the sealing effect is good.

8. Kiln hood

The kiln head cover is a cover shape made of welded steel plates. It sits on the kiln head operating platform through the legs on both sides, and the lower part is connected to the interface of the cooler. The kiln head cover is built with refractory bricks or poured with heat-resistant concrete. There are two suspended movable kiln doors on the front and outer end faces of the hood, so as to enter the kiln for maintenance and kiln lining construction.