What does a dry ball mill rely on to discharge materials? Analyze structure and working principle
Dry ball mill is a grinding equipment widely used in mining, building materials, chemical and other industries. Its discharge method directly affects production efficiency and product quality. This article will combine the technical discussions on hot topics on the Internet in the past 10 days to analyze the discharging mechanism of the dry ball mill from the perspective of structure, principle and data.
1. The core components of dry ball mill discharging
The discharging system of the dry ball mill mainly consists of the following structures:
| Part name | Function description | Technical parameter reference |
|---|---|---|
| Discharge end cover | Connect the cylinder and discharge device to withstand mechanical stress | Material: ZG270-500, thickness ≥50mm |
| grate board | Control the particle size of materials passing through and prevent the loss of steel balls | Grate width 5-15mm, opening rate 20-35% |
| Lifting board | Improve the discharge of qualified fine powder | Installation angle 45-60°, quantity 8-12 pieces |
| Discharge spiral | Forced conveying of materials (configuration of some models) | Pitch 200-400mm, speed 2-8r/min |
2. Working principle and discharging process
The discharging process of dry ball mill can be divided into three stages:
1.hierarchical screening stage: The material moves with the airflow after grinding. The fine particles pass through the gaps in the grate plate, and the coarse particles are bounced back to the grinding area.
2.Pneumatic conveying stage(Air-swept mill): High-speed airflow (0.5-3m/s) carries qualified fine powder into the separator. According to industry data, the production capacity of air-swept mills is 15-30% higher than that of ordinary mills.
3.Mechanical discharge stage: For center discharge mills, materials are discharged through the spiral channel in the hollow shaft. Typical parameters are as follows:
| Mill specifications | Discharge port diameter (mm) | Processing capacity (t/h) | Discharge particle size (μm) |
|---|---|---|---|
| Φ1.5×3m | 300-400 | 2-5 | 45-150 |
| Φ2.4×4.5m | 500-600 | 12-28 | 30-120 |
| Φ3.0×6.5m | 800-1000 | 45-75 | 20-80 |
3. Key factors affecting discharging efficiency
According to recent technical discussions in industry forums, discharging efficiency is mainly affected by the following parameters:
| Influencing factors | Optimization scope | Effect comparison |
|---|---|---|
| Grate plate opening rate | 25-30% | Every 5% increase in porosity increases output by 8-12% |
| Ventilation speed | 1.2-1.8m/s | When the wind speed exceeds 2m/s, the fineness decreases by 15% |
| Grinding body gradation | Φ30-90mm mixed | Reasonable grading can shorten the discharging time by 20% |
4. Latest technology trends (hot spots in the past 10 days)
1.Intelligent control system: A brand’s newly launched AI adjustment system can adjust the grate plate gap in real time according to the discharging particle size. It is said to reduce energy consumption by 18%.
2.Composite grate material: A new type of grate plate made of high chromium alloy (Cr ≥ 26%) has a service life extended to more than 8,000 hours and has become the focus of recent industry exhibitions.
3.Environmentally friendly renovation plan: The pulse dust removal and discharging system promoted by many companies reduces the dust emission concentration to less than 15mg/m³, which complies with the latest environmental protection standards.
5. Maintenance points
According to the maintenance data provided by the equipment manufacturer:
| maintenance items | cycle | Things to note |
|---|---|---|
| Grate inspection | every 500 hours | The grate seam wear exceeds 3mm and needs to be replaced. |
| Discharge end bearing | every 3000 hours | Grease filling amount does not exceed 70% |
| Air system | daily | Wind pressure fluctuation should be <5% |
Conclusion: The discharging system of the dry ball mill is the key to the efficient operation of the equipment and needs to be comprehensively designed based on parameters such as material characteristics and product fineness. With the advancement of intelligent control and wear-resistant materials, the discharging efficiency of modern ball mills has been significantly improved, which has also become an important direction for the recent industry technology upgrade.
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