At present, rotary kiln plays a vital role in metallurgy, building materials, minerals, and other industries. As large calcination equipment, a rotary kiln is composed of many components, which we called rotary kiln parts, including kiln shell(cylinder), kiln support roller, kiln thrust roller, girth gear and pinion, rotary kiln lamella or graphite seals at inlet and outlet.
As a professional rotary kiln manufacturer, we introduce all rotary kiln parts in detail.
Kiln shell
The shape of the rotary kiln shell includes straight cylinder, hot end enlarged type, cold end enlarged type, and both ends enlarged (dumb ling) type.
The kiln shell is generally made of Q235 (A3) steel plates of different thicknesses, usually 18, 20, 25, 28, 29, 32 mm and other specifications. In addition to the thick steel plate at the supporting kiln tyre ring, dozens of evenly distributed backing plates are installed on the circumference of the kiln shell, so that the force of the kiln shell is more uniform and the kiln shell is prevented from being worn by the kiln tyre. The body provides better heat dissipation conditions.
The kiln shell plays an important role in the whole rotary kiln. Although its surface is rough, it can reduce the flow speed of the powder and prolong the reaction time of the material in the kiln. The specific functions are as follows:
- The kiln shell can effectively reduce the heat dissipation loss of the kiln shell of the rotary kiln, play a good role in storing thermal energy, and greatly improve the thermal efficiency of the lime kiln.
- During calcination, the kiln shell attached to the refractory brick can act as a heat transfer medium. Because the kiln shell is in contact with the high-temperature air, it can absorb a large amount of heat in the air by means of radiation and convection, and then form full contact with the material at the lower part, and quickly transfer the heat to the calcined raw meal, thereby promoting the high-temperature environment in the rotary kiln equipment. The formation, the calcination effect, and speed of the tower-high material in the kiln.
- Under the action of long-term high-temperature calcination, the cylinder of the rotary kiln will inevitably be damaged to varying degrees. With the prolongation of material calcination time and the continuous increase of equipment processing capacity, the service life of the rotary kiln will gradually shorten. The kiln shell can protect the refractory bricks well, reduce the burning of the refractory bricks at high temperature, and prolong the service life of the refractory bricks.
Support device
The supporting device is composed of a kiln tyre ring, a supporting roller set, and a thrust roller set.
Kiln tyre ring
Rotary kiln tyre is also called rolling ring, its function is to transfer all the gravity of the cylinder (including the gravity of refractory bricks, internal devices and materials, etc.) to the supporting roller, so that the cylinder can rotate smoothly on the supporting roller, so the kiln tyre should have sufficient strength and durability. At the same time, the kiln tyre ring is a part that strengthens the radial rigidity of the cylinder, and should have sufficient rigidity.
Support roller set
The supporting roller set consists of a support roller, a roller shaft, and a bearing.
It is required that each pair of supporting rollers be installed in the symmetrical position of the center line of the kiln cylinder section, and the distance is equal to the sum of the radius of the supporting roller and the kiln tyre ring. At this time, the included angle between the center of the supporting roller and the center of the cylinder section is equal to 60°. When the supporting roller is installed in this way, the stability of the cylinder can be ensured without moving to both sides, and it will not be squeezed by the supporting roller. And it is required that each supporting roller shaft is parallel to the center line of the kiln to ensure that the kiln tyre ring and the surface of the supporting roller are in uniform contact.
Thrust roller set
The function of the thrust roller device is to indicate the axial movement of the kiln body (signal thrust roller) or control the axial movement of the kiln body (thrust block roller and hydraulic block roller).
The hydraulic working system of the hydraulic block roller is composed of an oil cylinder, an oil pump station, etc.
Working principle: When the kiln is started, the oil pump motor is started, so that the oil is sucked out from the oil tank, and enters the oil cylinder through the accumulator to push the piston to move the kiln body and the kiln tyre upward. When the wheel block of the block roller moves to the upper limit switch, the oil pump will be stopped, the power supply of the electromagnetic reversing valve will be connected, and the oil return circuit will be connected, and the oil in the hydraulic cylinder will adjust its downward channeling speed through the throttle valve. When the wheel block of the roller moves to the lower limit, the power supply of the solenoid valve is cut off, and the oil return oil circuit is also cut off, and at the same time, the oil supply pump motor starts and supplies oil to the oil cylinder.
Transmission device
The transmission device is one of the main components of the rotary kiln. In order to ensure the long-term safe operation of the rotary kiln, in addition to effectively ensuring the requirements of the “horizontal steel and longitudinal flexibility” of the kiln body and the reliability of the supporting device, stable and reliable transmission is also an important condition.
Components: SCR rectifier, DC motor speed regulation, main reducer, auxiliary transmission device, girth gears, and pinion.
The large girth gear (large ring gear) is installed on the rotary kiln cylinder, and transmits the power of the transmission part to the cylinder. It is one of the largest stressed components in the rotary kiln equipment. It is installed near the part of the supporting roller and thrust roller, the large girth gear and the kiln shell are connected by a welded spring plate or a pin-type spring plate, which can play a buffer role to protect the gear and the gearbox.
Sealing device
The sealing device is also one of the important components of the rotary kiln. The sealing performance of the kiln sealing has a great relationship with the normal operation of the rotary kiln.
Because the rotary kiln operates under negative pressure. If the kiln head and the kiln head cover are not well sealed, the external cold air will enter the kiln, and the certain proportional relationship between the amount of material, fuel and air in the kiln will be affected. Reducing the air volume of the secondary air entering the kiln from the grate cooler, reducing the temperature of the secondary air, increasing the heat consumption, and not good for the cooling of the clinker.
If the sealing between the kiln tail and the smoke chamber is not good, the negative pressure at this place is higher than that at the kiln head, it is easy to inhale a large amount of cold air, and it is difficult for the gas in the kiln to be discharged, so that the combustion of pulverized coal is incomplete, thereby increasing coal consumption and increasing The load of the large kiln tail fan.
Form of sealing device:
- Labyrinth type; the seals do not contact each other;
- Contact type: the seals are in contact with each other;
- Stuffing box type: rely on packing for sealing;
- Air-sealed type: rely on a small amount of external gas to form an air curtain for sealing.
