Axial flow fan quality appraisal

axial flow fan uses the core principle of impeller rotation to promote air flow along the axial direction, and is widely used in ventilation, air conditioning systems, industrial heat dissipation and other scenarios. In the construction field, it provides efficient ventilation for underground garages and shopping malls; in the power industry, it undertakes the heat dissipation task of power station equipment; in chemical companies, it is used for the safe transportation of flammable and explosive gases. Compared with centrifugal fans and mixed-flow fans, axial flow fans occupy a dominant position in medium and low-pressure ventilation systems due to their large air volume, low energy consumption, and compact structure. They are important equipment to ensure the comfort of industrial production and public environments.

As the application scenarios of axial flow fans expand, quality dispute cases are gradually increasing. Judicial disputes focus on: whether the equipment meets the performance indicators such as air volume, wind pressure, and noise stipulated in the contract; whether there is excessive vibration or structural damage caused by impeller imbalance and insufficient material strength; whether the control system is stable and reliable; and the correlation between quality problems, production accidents, and energy waste, etc. In such cases, the quality appraisal of axial flow fans uses technical means such as performance testing and vibration analysis to provide a scientific basis for the court to determine liability and loss compensation, and promote the standardized development of the industry.

Zhongke Testing is a product quality appraisal service organization registered with the court. It can provide axial flow fan quality appraisal services. It has a professional appraisal team and advanced instruments and equipment to provide fair and accurate appraisal results for axial flow fan quality appraisal.

Axial flow fan quality appraisal technical methods include:

1, appearance and structural inspection

Check whether the impeller and casing materials (such as aluminum alloy, fiberglass) meet the corrosion resistance requirements, and whether there are cracks or deformations on the surface. Check whether the installation angle of the blades is consistent, whether the connection between the hub and the main shaft is firm, and whether the sealing performance meets the standard.

2, performance parameter test

use anemometer and pressure sensor to measure the actual air volume and wind pressure to verify whether the design value is reached (such as air volume deviation ≤ ±5%). Test motor input power, calculate fan efficiency, and evaluate energy consumption levels.

0 conduct continuous running fatigue tests to record the bearing temperature rise and motor winding temperature change curves. Simulate extreme working conditions (such as high temperature and high humidity environments) to test equipment reliability.

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26, control system verification

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4 detects whether the functions such as frequency conversion speed regulation and overload protection are normal, and evaluates the rationality of the control logic. Verify sensor accuracy (such as temperature and pressure sensor error ≤ ±1%).

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67, on-site installation and environmental assessment

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8Verify the flatness of the installation foundation and the effectiveness of shock absorption measures to avoid the impact of resonance. Analyze the effects of pipeline resistance and air intake conditions on fan performance.

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A chemical company of the applicant signed an Industrial Axial Flow Fan Procurement Contract with a fan manufacturing company of the respondent, agreeing to purchase 50 axial flow fans of model DE-1000 for workshop ventilation. After the equipment was put into use, many fans experienced severe vibrations, excessive noise, and motor burnout. The chemical company believed that the fan had a design defect and demanded compensation for the loss caused by the production shutdown. The wind turbine company argued that the problem was caused by improper installation or overloaded operation, and both parties went to court. The court entrusted a third-party appraisal agency to conduct quality appraisal of the wind turbine involved in the case.

Identification analysis results:

The quality analysis expert group discussed and comprehensively analyzed the relevant information of the "axial flow fan", contract technical agreement, on-site investigation case materials and other data, and made the following quality analysis opinions:

1. The thickness of the impeller blades of the axial flow fan involved in the case was uneven (maximum deviation 0.5mm), resulting in dynamic balance imbalance. The gap between the casing and the impeller is too large (design value 2mm, actual measurement 4-6mm), causing air flow turbulence.

2, the measured air volume of the axial flow fan involved in the case was only 75% of the rated value, and the wind pressure dropped by 30%, which was unable to meet the ventilation needs. The operating current of the motor exceeds the rated value by 20%, causing the winding to overheat and burn.

Axial flow fan quality appraisal report should include the following content:

1. Information about the appraisal client and the appraised party.

2. Testing items, sampling methods, testing methods and equipment.

3. Test results and analysis.

4. Quality evaluation conclusion.