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Technical transformation of raising production and reducing


1 reconstruction background


1.1 equipment status

(1) cement grinding specifications for Φ 3.8 m x 13 m center driving mill, roller press is chengdu lijun CLF140-65, configuration N2500 efficient classifier, initial roll 1 400 mm diameter roller press, roller surface width is 650 mm, design materials with capacity of 235 ~ 335 t/h, mill production is 110 t/h of the design, in the operation of the bread is expected to improve the mechanical and electrical current of 180 ~ 200 A.
The roller press was put into use at the beginning of 2010 and was used for 6 years in 2016. With the extension of the service time, uneven wear appeared on the roller, which was manifested as light wear at both ends and heavy wear in the middle. Before replacing the roller, the left and right ends of the roller were measured at 100 mm and the middle position respectively.
It can be seen that there is a difference of 53.5 mm from the maximum diameter of the initial roller.
(2) this roller press was changed from ordinary roller to composite wear-resistant roller in January 2010, and has been in use for 6 years till the end of 2015.
In the middle, although the roller diameter and one word grain have been welded for many times, the overall size of the roller diameter becomes smaller, the extrusion effect of the roller press is not ideal, and the roller of the roller press has reached the replacement time limit.
(3) as the roller has been used for 6 years, the material on the surface of the roller appears fatigue damage, and the surface of the roller cannot be surfacing again (the welding patch is easy to remove the material of the surface of the roller due to the large welding stress).
If the roll surface by carbon arc air gouging, tearing up again after polishing required for welding wire, high maintenance cost (two roll need wire about 1 000 kg, 180 yuan per kg wire, plus other material maintenance down to about 200000 yuan), and long maintenance period (24 h a day construction about 15 d) and only 8, 000 h, the service life of the price is too low.
(4) as the roller diameter of the roller press becomes smaller, materials cannot support the roller of the roller press, resulting in smaller gap of the roller press during operation, low working pressure and poor extrusion effect of materials.
For this reason, we changed the thickness of the middle pad between the moving roll and the fixed roll from 80 mm to 50 mm (after each change, the pressure of the roller press should be added to the working pressure before starting the machine, and the manual disk moves the moving roll and the fixed roll for one week to ensure that there is no friction between the moving roll and the fixed roll and between the roller and the roller cover).
For moving forward roll as a whole, in order to avoid the hydraulic cylinder stroke is not enough (hydraulic cylinder stroke 50 mm), in the front moving roller hydraulic cylinder on the roof padded a 20 mm thick steel plate, to prevent the hydraulic cylinder after fully extended no top to the roof and damage (, shall be in accordance with the rolling roller overall moved forward after the machine instructions to move to roll and roll motor, to ensure the safe operation of the roller press).

1.2 process status

(1) as can be seen from table 1, uneven wear occurs at both ends of the roll, causing the intermediate material to pass through the roll without extrusion or small extrusion pressure. In order to ensure the feed volume of the mill, only increase the air volume of the circulating fan, causing the large particle material to be pulled away.
(2) performance on A rolling machine to run the current low, rolling machine is configured with two 500 kW, 10, 000 V high voltage motor, rated current is 36 A, the actual running current is 18 ~ 22 A, only 50% to 61% of the rated current, small motor actual power, and cause mill production is low, power consumption is high, the loss of the roller press and cement mill combined the advantages of grinding.

2. Determination of transformation scheme

Before replacing the roller, our company investigated other manufacturers and communicated with the technical department of the roller press manufacturer, and determined the following two schemes:
(1) our company Φ 3.8 m x 13 m cement grinding the original configuration of 140-65 type roller pause slants small, can't give full play to the advantages of combined grinding, then Φ 3.8 m x 13 m cement mill roller press, 150-100 are configuration, output capacity of 220 t/h.
In view of this, a new set of 150-100 roller press can increase the output and reduce power consumption, the disadvantages are high cost, long construction cycle.
(2) without changing the reducer, motor, upper and lower frame and hydraulic control device of the roller press, the width of the roller is widened from the original 650 mm to 750 mm, so as to increase the capacity of materials passing through the roller press and increase the work efficiency of the roller press.
The ideal operating current of the roller press should be 70%~85% of the rated current. Operating in this range can not only ensure the safe and stable operation of the equipment, but also give full play to the maximum capacity of the roller press.
The running current of the new roller of our company does not exceed 25a. After calculation and verification by the technical department of the roller press factory, it is considered that the original motor and reducer can meet the requirements of safe operation after the widening of the roller surface.
After considering various factors, our company decided to adopt the plan of widening roller surface.

3. Transformation measures

(1) the roller is replaced by the roller press. The roller surface is adjusted from 650 mm to 750 mm, and the diameter of the roller remains unchanged.
(2) the feeding device has been modified
The roller press is originally configured as a single feed device, which USES handwheel, lead screw and connecting rod to connect the feed plate, and controls the feed quantity by shaking the handwheel to control the opening of the feed plate.
In the actual work, because the mechanical device adjustment is laborious, and because the adjustment plate is a plate, its adjustable range is small, so by adjusting the flow adjustment plate to change the roller press running current and the effect of roll opening is very limited.
In this technical reform, our company changed the original single feeding device into double feeding device. The principle is that two feeding plates open to adjust, and the adjustable range is greatly increased. The adjustment mode is changed from the original manual adjustment to electric actuator adjustment.
The central control operator can adjust the scale of feed plate at any time according to the running current of the motor and the opening of the roll.
Feed plate opening becomes larger, running current and roll gap become larger, and vice versa.
(3) increase the height of the weighing stable flow bin and increase the material pressure of the roller press
The feeding slip height between the cone of the original weighing stable flow bin and the feeding device of the roller press is 2m, and the part of the roller press is pressed down to reduce the work done by the roller press.
This technical reform, our company moved the whole weighing stable flow bin up by 1.5m, making the cone feed slip height reach 3.5m, increasing the material pressure of the roller press, increasing the material of the roller press per unit time, and improving the work efficiency of the roller press.
(4) the breaking lattice of v-type separator was modified
First of all, the serious wear of the broken lattice was replaced, followed by a technical reform of the V classifier feeding chute, changed the original feeding bias phenomenon, so that the material can be evenly into the V classifier, avoid the mass of materials into the V classifier into the weighing warehouse.
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