Large cement mill and raw material mill hot spot coolingDate: 2019-07-10 Views:
Cement mill and raw material mill because of different grinding materials, its hot spots are also different.Cement grinding because of grinding clinker temperature is generally higher (especially in summer), hot spots are grinding tail spindle tile and main reducer shaft tile;Due to the use of hot air from the humidifying tower at the end of kiln as the drying heat source, the hot spots are the sliding shoe bearing bush (grinding head) and the main reducer bearing bush.
In view of the above hot spots, we have adopted different cooling measures, received a good effect, improve the cement mill, the original axle bush operating temperature in summer.
1, cement grinding hot spot cooling
Our factory is equipped with cement grinding model of Ф 4 m x 13 m ball mill, 2 800 kW power, USES the center drive, the main reducer JS140 - A, its rare gas station model is XYZ - 350, so the heat exchange area of 21 m2;The type of thin oil station equipped with the mill's main bearing bush is xgo-a2.5/40, with a heat exchange area of 5 m2.In summer, due to the influence of external temperature, the temperature of grinding end spindle bush and main reducer shaft bush is often around 60 ~ 62 ℃, usually the normal temperature range required to control is < 60 ℃ (grinding head spindle bush is 5 ~ 6 ℃ lower than the grinding end).
1.1 cooling improvement measures
We are in the cement mill main reducer thin oil station and grinding end spindle tile thin oil station cooler, respectively in series 1 tube cooler, in order to achieve the purpose of effective control, designed a number of valves, in order to achieve different seasons, different heating temperature temperature control.
1.2 effect after improvement
The cooling device of cement mill thin oil station has been improved in series since 2004. It is easy to control the temperature of hot spots. Even in hot summer, the heating temperature of each lubrication point is below the safe value.Js140-a reducer for cement grinding has two bearings, 10 bearing pads, 12 temperature measuring points, and two temperature measuring points for grinding tail main shaft tiles.The temperature comparison before and after improvement is shown in the table
2, the original heat drop
My factory use original Ф is 4.6 m * (3 +) 10 m drying in discharge mill, use among slipper support, with the main reduction of maxhine JS150 - B, center drive, power 550 kW.For the hot sliding shoe bearing shell and main reducer bearing shell, we adopt the method of air-cooled sliding shoe and water-cooled thin oil station to achieve the purpose of cooling down.
2.1 cooling of original sliding shoe bearing bush
Using compressed air to cool the inside surface of sliding shoe can effectively reduce the temperature of bearing bush of sliding shoe.Air cooling device with Ф 25 mm steel pipe, welded into a "C" shape framework, fixed on the outside of the slipper seal cover.
The C "frame wraps the slide shoe inside the outer edge of the mill barrel.Two endpoints of a framework, along the inside of the width of the slipper, respectively have four open Ф 8 mm holes, the position of the holes are on the slipper.One end of the frame is connected to the compressed air pipe and a valve is installed to control the air flow.
When the original sliding shoe temperature reaches 60℃, open the valve to cool the sliding shoe, and adjust the valve opening to the appropriate degree according to the temperature of the bearing bush of the sliding shoe.In hot summer, the device can be kept on, so that the maximum temperature measuring point of sliding shoe can be controlled at 55 ~ 57 ℃.
2.2 cooling of axle bush of original main reducer
The main reducer js150-b has a large body and a large heat dissipation area.The main reducer in operation, only a few bearing bushes exist high temperature phenomenon, for its cooling, the use of water cooling thin oil station.
2.2.1 cooling measures for axle bush of main reducer
The heating hole of xpz-400p thin oil station is used for cooling.The thin oil station is equipped with a very distinctive heating device, which is a jacketed heating device. The heating wire of the heater is in a closed sleeve and does not come into direct contact with the lubricating oil.We will use this special device, the heater removed, and then homemade water inlet and outlet pipes, water cooling.Among them, the length of the inlet pipe should be longer, 50 mm from the bottom edge of the sleeve is advisable, and the length of the outlet pipe should be shorter and controlled at 100 mm.The inlet and outlet pipes are welded to the flange at the same time. The size of the flange is the same as that of the end face of the heater.Before fastening the bolts, put a 2 mm rubber pad under the flange to prevent the flange from leaking.Finally, connect the water pipes with rubber pipes, and tie the joints of rubber pipes with iron wires.
2.2.2 matters needing attention
Attention should be paid to this measure: the original design of thin oil station pipelines are all seamless steel pipe, flange connection, argon arc welding, so that there is no leakage.But for the sake of safety, before using water cooling, the heater jacket to do the hydraulic test, with the water pressure test of 0.4MPa must not have the phenomenon of water seepage.After the cooling water is connected, the water pressure is controlled below 0.2mpa.In winter, the heating device should be restored, and the jacket should be air-dried before recovery, and the heating wire should be tightened after the inner hole of the jacket is dried.
2.2.3 water cooling effect
The thin oil terminal has six coordinate HRY sheathed type electric heater, sheath size: Ф 110 mm x 1200 mm, after changing water cooling device, the interior of the equivalent of dilute oil station, added a cooler surface area is 2.54 m2.In the summer of 2005, we first carried out an experiment on line #1, and the cooling effect was very obvious.In the summer of 2006, we expanded to line 2.The original main reducer is the same as the cement mill main reducer. It has two bearings, 10 bearing tiles and 12 temperature measuring points.The temperature of each axle bush of the main reducer before and after improvement is also shown in the table
3. The conclusion
(1) the cooling of large cement mill and primary lubrication hot spots is very important in production. If the cooling measures are not timely, it will not only affect the normal operation of the mill, but also may cause tile burning accidents.
(2) summer is the production and sales season, the cement mill operation rate is relatively high, cement sales demand, the main shaft tile cooling is very important.We adopt the measures of tandem cooler is more appropriate, the investment is only about 20,000 yuan.Compared with the original cement mill operation rate is lower, and grinding material temperature is not high, using air-cooled slide shoes and water-cooled thin oil station can meet the cooling requirements.Of course, if the original use of series cooler cooling method is also ok.