The deep well fire pump is a vertical multi-stage centrifugal pump that can lift water from deep wells. As the groundwater level drops, deep well fire pumps are used more extensively than general centrifugal pumps. However, due to improper selection, some users have problems such as failure to install, insufficient water output, failure to pump water, and even damage to the well. So, how do users choose deep-well fire pumps?
1. Preliminarily determine the water pump type based on the well diameter and water quality.
Different types of deep well fire pumps have certain requirements for the diameter of the well hole. The maximum external size of the water pump should be 25~50mm smaller than the well diameter. If the wellbore is skewed, the maximum overall size of the pump should be smaller. In short, the pump body part cannot be close to the inner wall of the well to prevent the vibration of the deep well fire pump from damaging the well.
2. Select the flow rate of the deep well fire pump according to the water output of the well.
The flow rate of the deep well fire pump should be equal to or less than the water output when the well water level drops to half the well water depth. When the water pumping volume is greater than the water output of the well, it will cause the well wall to collapse and siltate, affecting the service life of the well; if the water pumping volume is too small, the benefits of the well will not be fully utilized. Therefore, the best way is to conduct a pumping test on the well and select the deep well fire pump based on the maximum water output that the well may provide.
3. Deep well fire pumps should not be installed and used in wells where the sand content in the well water exceeds one ten-thousandth.
Because the sand content in well water is too high, if it exceeds 0.1%, it will accelerate the wear of the rubber bearings, cause the water pump to vibrate, and shorten the life of the water pump.
4. Determine the actual lift required for the deep well fire pump based on the depth of drop in the well water level and the head loss in the water pipeline. It is equal to the vertical distance from the water level to the water surface of the outlet pool plus the loss lift. The loss head is usually 6~9% of the net head, 1~2m. The water entry depth of the lowermost impeller of the water pump should be 1~1.5m. The total length of the underground part of the water pump tube should not exceed the maximum length specified in the water pump manual.
