Problems in the original crushing system of the cement plant
The equipment used by the company for crushing limestone is a traditional hammer crusher. This model has a large feed size and can crush the material to the size that can enter the mill at one time. It has high impact efficiency and easy maintenance.
However, in order to meet the requirements of one-time discharge and molding of the equipment, the design spacing of the grate plates of the crusher is narrow, and because of the high content of clay and scraps in the mine raw materials, this part of the clay and scraps are likely to fall on the grate plates after being fed into the crusher. Accumulation is formed, which will cause poor discharge of the hammer crusher and serious hammer head wear.
If the feed volume of the apron feeder increases, the material cannot be broken and discharged in time, which will cause the current of the apron feeder motor to exceed the limit current, and the feed volume has to be reduced, resulting in a serious decline in output. This restricts the discharge capacity of the hammer crusher. The actual output of <50 mm is 500-700 tons/hour.
After the engineers surveyed and mapped the equipment, the solutions proposed are as follows:
- Change the original hammer crusher to a new single-stage hammer crusher.
- Move the center position of the single-stage hammer crusher’s discharge port forward (toward the feeder) on the basis of the original crusher’s center position. After moving forward, the original discharge port of the original crusher can still be used.
- The installation foundation of the original crusher remains basically unchanged. The crusher uses a 300 mm steel structure elevation base to connect with the original foundation anchor bolts. The crusher motor is replaced with a 1250kw motor, and a set of transmission devices are replaced. The position of the adjusting slide rail bolthole of the transmission device is redesigned and the adjusting slide rail is connected with the original anchor bolts.
- Re-make 4 pieces of 400x400mm embedded iron to connect with the shaft extractor.
- The non-standard connecting parts of the hammer crusher port and the plate feeder are re-made according to the site conditions.
Actual operation effect after transformation
|Before improvement||After improvement|
- When starting up: the rotor runs smoothly and the starting current is normal.
- Feeding: uneven incoming materials, maximum 1200 mm.
- Output: when the particle size is large, the content of clay and scrap materials is high (up to 50% in severe cases), and the feed rate of the board feeder reaches the normal production frequency, the production is still smooth, the average output is 1100~1200t/h, the peak value It can reach 1300t/h.
- Discharge: After the screening test, the discharging particle size is below 50 mm, accounting for 90%.
- Current: The power of the board feeder is 55KW, the motor current is stable during use, and the feeding capacity of the board feeder has room for improvement; the motor power of the crusher is 1000KW, the rated current is 69.2A, and the current of the crusher is 45~ 47A, less fluctuation.
The overall condition of this renovation is good. Under the premise that the overall particle size of the material is large, the content of clay and scraps is large, and the output reaches the normal requirement, the equipment is running well, and the effect of increasing production is very significant. And there is a large surplus. When the materials are broken, there is a large production space, and the equipment is easy to replace, the original civil construction foundation is minimally changed, the installation and maintenance are convenient, and the energy consumption is low. This technical transformation also proves the new single-stage the superiority of hammer crusher.