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Determination of adjustable basic parameters of roller press

Date:2019-07-04 16:32 Source:未知Views:

The roller press is the same as the roller crusher, but its function is different, and there is an essential difference. It was introduced from Europe in the 1980s and has been widely used in cement companies. It has already dominated cement grinding. Here is a brief introduction to the main parameters combined with personal understanding.

How the roller press works


The roller press consists of two rollers (ie moving roller, fixed roller), frame, reducer, torque support, motor, pressurizing system and feeding and discharging device. When the two rollers are driven in the opposite direction by the power, the material from the upper part is pulled into the gap between the two rollers, and then the hydraulic cylinder installed on the rear side of the moving roller starts to pressurize, and the driving piston advances, and Push the moving roller to apply pressure to the material. As the two rolls continuously pull the material into the roll gap and carry out compaction and crushing, and the cake is discharged, the finished cake is broken into the grinding or storage, and the unqualified product is returned to continue to be crushed, so that the powder is finally obtained. mill.

The pressure of the roller press is a key parameter related to the efficiency of the work, and should not be underestimated. The yield of the finely ground fine powder is almost determined by the pressure. According to relevant information, Schneider's experimental data is: when the pressure is 60MPa, the pass rate of 32 micron fine powder is about 20%, if the fine powder content is increased to 30%, the pressure needs to reach 100---300MPa. At the same time, experiments show that when the pressure is high, the increase of fine powder yield is not obvious, but the power consumption is multiplied. At the same time, because the pressure is increased, the cake is not easy to be broken, and the tube grinding power consumption will also increase. The experimental conclusion on the small roller press is that when the pass rate of 45 micrometers is 36.1%, the required working pressure is 205 MPa, and it can be seen that the pass rate of 80 micrometers is higher. Domestic data show that the average roll pressure of 120-150 MPa, 0.08 fine powder yield can reach 50%.

From the domestic and international data, combined with the actual situation, the average rolling pressure should be greater than 60MPa, if it can reach 100MPa or more, so that not only the fine powder yield is high, the roller press has high work efficiency, but also reduces the cyclic load, conveying equipment. The energy consumption will also be reduced, which will help reduce the system power consumption.
It must be reminded that, due to the large difference in material of each unit, it is recommended that the lowest average rolling pressure should not be less than the strength of the highest strength material in the material, preferably about 1.5 times or more. The cylinder pressure can be estimated in this way.

P=1.5DB/dd

In the formula:

P is the cylinder pressure MPa

D is the roller diameter m

B is the roller width m

d is the cylinder diameter m

In general, the final P selection depends on the strength of the reference material. If you want to accurately set the P value, you can filter the cake by 0.08 sieve, measure the fine powder content, and then determine. Simply judge whether the pressure is appropriate, you can hand the cake, so that it can be opened.

2. Control of feed particle size


The feed size of the roller press can be determined by 3.5% of the roll diameter. Under suitable pressure, the operation is stable and should not be too large. The data show that when the particle size is 7.0% of the roll diameter, the current fluctuation of the roll press will increase. Several times, it is not conducive to stable operation.

3. Choice of roll gap


The roll gap is also one of the important parameters of the roll press, typically 2.0% of the roll diameter. The original roll gap is generally about 10 mm. Here, it is necessary to remind that before setting the original roll gap, the radial detection of the roll radial run is required, and the most prominent positions of the two rolls are respectively turned to the opposite horizontal positions, and then the limit is fixed. The block has a gap of about 10 mm and the two axes are parallel.

4. Installed power of the roller press


The data show that when the average roll pressure is 60MPa, the power consumption of the ton material is 2.4KW, but the actual pressure will be around 1.5. The experimental data proves that it takes 3.5KWH to crush one ton of clinker and 3.0 for one ton of limestone. KWH, slag 6.0KWH, then the installed power should be greater than this value.

5. Selection of roll gap displacement


The roll gap of the roller press is best stabilized, but in actual operation, due to the change of particle size, oil compressibility, vibration, etc., the change will inevitably occur, but the roll gap is not allowed to expand indefinitely, and one must be set. A reasonable displacement, if the displacement is too large, will exceed the self-positioning angle of the bearing and damage the bearing, so it must be limited. The general offset is controlled at 3 to 5 mm, but it is best calculated by the allowable rotation angle of the bearing. It not only ensures the safety of the bearings, but also guarantees the extrusion effect.

6. Roller line speed


The linear velocity of the roller is closely related to the yield, but the experiment proves that the linear velocity relationship is linear with the yield when the linear velocity is 0.2---1.5m/s; the relationship between the yield and the velocity when the linear velocity is 1.5--1.8m/s. The drop indicates that the ability of the roller to bite the material is decreasing. Therefore, the linear speed of the roller press should be below 1.8m/s.

7. Production of roller press


The output of the roller press is measured by the throughput, and is related to the roll speed, the weight of the cake and the thickness, and the width of the roll. which is

G=3600BVSp(t/h)

In the formula:

G station hours / hour

B roller width meter

V roller line speed m/s

The thickness of the S cake is about 2.25% of the diameter of the roll.

The weight of the p cake is about 2.4 tons/m3.

Conclusion:


In fact, after the roller press is installed and used, the structural parameters can not be changed. Only the pressure, the offset of the roll gap, the size of the material, and the amount of circulating materials can be adjusted. The pressure is the most critical data, which directly affects the work efficiency and fine powder yield; the difference of roll gap affects both the bearing installation and the rolling effect; the grain size involves the stability of operation; the amount of circulation also involves the compactness of the incoming material. In the case, too much fine powder or too much granular material will cause excessive air to enter, which is not conducive to stability and the like. At the same time, the reader is reminded that due to the limited level of the author, it is inevitable that mistakes will occur, so please criticize and correct. Thank you!

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