Greensboro project case “Ethiopia rotary kiln gearbox modification”.

Greensboro project case “Ethiopia rotary kiln gearbox modification”.

Project Location: Ethiopia Horetta Habasha Cement Co.

Owner's requirement: Increase the rotary kiln speed (n1~n2) from 0.396~3.966r/min to 0.46~4.6r/min, so as to respond to the increase of rotary kiln output.

The specification of the existing rotary kiln is Φ4.6×62m, the rotating speed of the rotary kiln is 0.396~3.966r/min, and the parameter of the existing kiln reducer is shown in Figure II.

Greensboro program:

In order to save as much as possible technical transformation investment costs, in communication with the customer, fully understand the actual operation of the site equipment. Developed a technical reform program. The program suggests to take advantage of

The program proposes to take advantage of the existing reducer shell and input and output couplings, and only make technical adjustments to the internal connection shaft and gear structure of the reducer. To ensure that the input and output shafts in the shaft diameter,

distance and center height of the shafts are consistent with the existing reducer. To realize the purpose of adjusting the rotary kiln speed by replacing only the internal structure of the reducer. The advantages of this program are as follows:

1. The kiln stopping time is short, the internal structure of the reducer can be replaced in about 5 days.

2. Low investment cost of the equipment, the main and auxiliary motors and the corresponding couplings and diaphragm couplings can be completely depreciated. The existing reducer housing does not need to be replaced either. Maximum

The existing components are utilized to the maximum extent. No civil engineering work, low total investment cost.

4. The original parameters are customized to ensure the stability of equipment operation.

Calculation is based on the following, in the case of rotary kiln inclination, large and small gear ring, main motor remains unchanged, it is possible to reduce the main speed reducer by

Under the condition that the tilt of the rotary kiln, the size of the gear ring and the main motor remain unchanged, the speed of the rotary kiln can be increased by reducing the speed ratio of the main reducer.

The speed ratios i1, i2 of the old and new reducers and the new and old rotary kiln speeds n1, n2 satisfy the following equation.

Relationship equation:

i1 : i2 = n2 : n1

The speed ratio of the existing gearbox is i1 = 50.985, and the speed of the rotary kiln is n1, n2. The speed ratio of the existing gearbox is i1 = 50.985 and the speed of the rotary kiln is

n1 = 0.396 to 3.396 The rpm of the rotary kiln is n1 = 0.396 ~ 3.966. The rotor speed of the rotary kiln is n1 = 0.396 ~ 3.966 r / m i n .

n2 = 0.46 ~ 4.6 r/min.

Then the speed ratio of reducer: i2=i1*n1/n2=50.985*0.396/0.46=43.89

Or: i2=i1*n1/n2=50.985*3.966/4.6=43.96

Take the speed ratio of reducer: i2=43.94

Required power of main motor after speed up of rotary kiln:

N=K*D2.5*n*L

=0.052*(4.6-2*0.2)2.5*4.6*62

=536(kW)

So choose 560kW.

N = rotary kiln main motor power

K= coefficient (dry kiln K=0.048~0.056)

D= Effective inner diameter of rotary kiln (M)

n= rotary kiln speed (RPM)

L= length of rotary kiln (M)