Every coal mine is inseparable from the mining and construction production of drainage equipment. The task of the mine drainage equipment installed in the underground mine is to discharge the mineral water to the ground in time, creating a good working environment for underground production and ensuring the safety of underground workers. And the good operation of machinery and electrical equipment. Therefore, the selection of the main drainage equipment, especially the drainage pump, must comply with certain regulations.
The capacity of the main drainage equipment pumping station for mines shall meet the following requirements:
1. The main drainage pump station for mines must be equipped with three drainage pumps, one for work, one for standby and one for maintenance and repair. A spare drain pump is used to ensure replacement and maintenance in the event of an accident. At the same time, it must also meet the needs of eliminating the maximum gushing water.
2. The capacity of the working mine drainage pump should be able to discharge the normal water inflow of 24 hours in the mine within 20 hours. The capacity of the standby water pump should not be less than 70% of the capacity of the working mine drainage pump. The total capacity of the working water pump and the standby water pump should be able to discharge the maximum water inflow of the mine day and night within 20 hours. The capacity of overhauling the water pump should not be less than 25% of the capacity of the working water pump. For mines with complex hydrogeological conditions, a place for additional pumps must be reserved in the main pump room. Two water pipes must be equipped, the passing capacity of which is adapted to the working water pump and the standby water pump respectively, so that the two water pumps can be started at the same time to ensure drainage in the rainy season.
3. The main drainage equipment should work at the highest possible efficiency. The main drainage equipment must work safely, reliably and economically to ensure safe production in the mine.
4. For mines with complex hydrogeology and danger of water inrush, wear-resistant drainage pumps for mines can be added according to the situation, or a place for installing water pumps can be reserved in the pumping station.
5. The calculation of the capacity of the mine drainage pump should be based on the working displacement of the pump when the spare pipeline is not put into use and the working pipeline has been silted; the calculation of the total capacity of the working and spare pumps should be based on all the pipelines being put into use, and The displacement of the pump under the condition that the pipeline has been siltated shall prevail; the additional drag coefficient caused by the pipeline siltation can be taken as 1.7.
6. When calculating the capacity of the pumping station, if the inner diameter of the pipeline is different, the resistance loss should be calculated in sections.
The selection of wear-resistant mine drainage pumps should meet the following requirements:
1. Mine drainage pumps should be selected from certified high-efficiency and energy-saving products of the same model and manufacturer, and wear-resistant multi-stage centrifugal pumps should be selected.
2. The working condition of the water pump during the whole operation period should be in the high-efficiency zone, and the efficiency should not be lower than 70%.
3. The suction centrifugal pump should make the installation height of the pump conform to the following formula:
Hz≤Hsmax (4.1.2-1)
Hsmax=(pa'-pv')/γ-【△h】-【△hs】
Where Hz—the installation height from the center line of the pump shaft to the bottom of the sump (m);
Hsmax—the maximum suction height allowed by the pump (m);
pa'—Atmospheric pressure at the installation location of the pump (Pa);
pv'—the saturated vapor pressure of the actual water temperature at the installation location of the pump (Pa);
γ—The gravity of mine water (N/m³), 10x10³N/m³ can be taken when there is no actual data;
【△h】—The resistance loss of the suction pipe (m);
【△hs】—The necessary cavitation allowance for water pump samples (m);
When the sand content exceeds 5-10kg/m³, the water absorption height should be appropriately reduced or the calculated weight of the mine water should be increased.
The calculation and selection of the motor capacity of the multi-stage pump for mining shall meet the following requirements:
The motor capacity should be calculated by the following formula;
Where N—calculated capacity of the motor (kW);
Hw--the pump head when the pipeline is not siltated (m);
Qw—The pump working condition flow rate when the pipeline is not siltated (m³/h);
ηw—The efficiency of the pump working condition when the pipeline is not siltated (%);
ηm—mechanical transmission efficiency, the coupling can be 0.98;
K—The surplus coefficient of the motor. When the shaft power of the multi-stage pump for mining is greater than 100KW, it can be 1.1; when the shaft power of the water pump is less than or equal to 100KW, it can be 1.1~1.2.
The motor selection should comply with the relevant regulations in Chapter 6 of this code, and should be able to withstand a reverse rotation speed 1.2 times the rated speed, and last for 2 minutes without harmful deformation.
