A complete ventilation system is a prerequisite for safe production in mines. Due to the difference in manufacturing and installation quality, many additional devices (such as diffusers, mufflers, etc.) have been added to the actual production mines, and the performance of the ventilators is constantly changing due to operational wear, rust, and maintenance.
In addition, in order to ensure safe production, according to the requirements of 5 regulations 6, the production mines with service years of more than 5 years must be mechanically ventilated, and at the same time, 2 sets of ventilators (including electric motors) of the same capacity must be equipped, one of which is reserved. .
However, in some production mines, the backup fan and the running fan share a set of anti-wind system, so that it can not use the anti-wind channel to form an independent short-circuit air intake system when measuring the standby fan, so that the backup fan cannot be measured; Ancillary facilities of the ground ventilator system, such as wind rafts, diffusers, maintenance doors, etc., in order to ensure no air leakage and durability, generally have certain requirements in terms of material selection, thickness and strength. It is very difficult to brush the large inspection door, and it will also damage the integrity of the ground ventilator. After the measurement is completed, it is difficult to restore the original condition, so the method is generally not easy to adopt. Through the above analysis, when the performance of the standby ventilator cannot be measured by a conventional method, it is necessary to develop a method for how to safely and reliably measure the performance of the operating ventilator.
Determination of the measurement plan According to the specific conditions of the site, there are three kinds of solutions that can be used for reference: (1) the fan is short-circuited by the anti-wind door; (2) the large inspection door area is used to measure the standby fan; (3) the explosion-proof door is used. The sidewalk damper and the plate resistance method are combined with the adjustment working conditions to determine the running fan.
Comparison: Option 1 needs to stop production; Option 2 needs to brush the large inspection door to a sufficient area. Because the inspection door is reinforced concrete pouring, the construction is very difficult; the first working condition and the last working condition point in Scheme 3 will be different. The degree of influence on the downhole flow (about 68min). Considering that the mine is a low-gas mine and is not a single-wind work, it will not bring unsafe factors to the well in a short period of time, and in addition to the strict / ventilator performance The safety technical measures were determined, and it was finally determined that the measurement was carried out using the scheme 3.
Specific practice: the first working point will open the explosion-proof door and the sidewalk damper to maximize the air volume; the second operating point will be measured after the explosion-proof door is closed; then the sidewalk damper will be closed to measure the third working point. At this time, the fan is actually in a normal downhole load operation state. From the fourth operating point point and afterwards, each working condition point is adjusted by the plate resistance method. The working condition adjustment is arranged in the wind raft, and the section is the static pressure section.
The individual characteristics of the NQ and GQ fans. At the same time, the sample characteristic curve of the fan is also drawn to verify the reliability and correctness of the actual measurement. The curve is the measured HQ characteristic curve. Through the comparison of the two curves, the change trend is consistent, and the measured fan pressure curve conforms to the variation law of the axial flow fan pressure.
The operating point with the downhole network load is basically on the measured wind pressure-air volume characteristic curve. It can be shown that the measurement result is reliable. The characteristic curve can be used to analyze the operating condition of the fan and to circulate the reasonable use in the future. The machine has realistic guiding significance.
Conclusion Through the performance measurement of the test fan of No. 2 wind turbine of No. 3 wind shaft of Qianqi Coal Mine of Yima Mining Bureau, through calculation and drawing analysis, the following experiences are obtained: (1) Compared with the brush inspection door, It has the convenience of measurement and does not damage the integrity of the fan device; (2) The preparation work before the method is small, saving money; (3) The accuracy of the measurement can meet the production needs, and can correctly analyze the actual operation of the fan. The role of the state; (4) during the entire measurement process, does not substantially affect the normal production of the mine, especially suitable for low gas mines that cannot directly determine the performance of the standby ventilator.
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