Choosing a water pump for a private home: specialist advice
Please help me choose the pumping equipment for the water supply of a summer country house (watering the garden is not planned).
The source is a pipe from a spring near the house, water flows by gravity. Made an inch pipe retraction. The house is located on a hill (smooth climb uphill) from the pipe at a distance of 80 meters with a total difference of about 8 meters. There is enough natural pressure in the pipe to raise water through the hose to a distance of 10 meters with a difference of 2 meters (the result of the experiment).
It is advisable to place pumping equipment in the territory of my yard (10 meters from the house, not further).
Water supply via a water station is preferred (if possible).
Michael
Expert Answer
Hello, Michael.
Your task is solved by simple calculation of pressure and flow characteristics of the pump. To obtain data on the minimum head of the unit, it is necessary to calculate the losses in all areas and add a small margin of productivity to this value. In addition, you should determine what water flow rate will satisfy your family's needs per unit of time.
It is best if the pump will be located directly at the source or at a small distance from it. For your conditions, the water supply installation will have to provide a water rise of 16 m, since every 10 m of the horizontal section of the highway is equated to 1 m of vertical supply. If you install the unit at a point where the water reaches by gravity (2 meters up, 10 meters horizontally), then the minimum head can be reduced by 3 m. Therefore, the desired value will decrease to 13 m.
Note that in any case, the pressure value must be multiplied by 1.15 (hydraulic resistance coefficient) and the flow value increased by another 10-15%, otherwise the pump power will be enough only for the water to reach the tap - at best, you can observe a thin stream liquids. And these are only minimal (not to be confused with nominal) indicators. Given the voltage drops in the network, the quality of modern electrical equipment and other factors, we recommend making a two-time supply margin for the pressure characteristic for normal operation of the unit.
As for the flow rate, you should determine how much water your family uses per day and find out the maximum instantaneous consumption. The last value can be calculated based on the number of all consumables in the house. So, up to 10 liters of water passes through the shower faucet per minute, the taps of the washbasin and the kitchen sink “dispense” another 6 liters, and the toilet bowl - about 4 l / min.
Immediately, we note that a flow rate of 25-30 l / min will be quite enough, since cases of simultaneous switching on of all valves are infrequent. In addition, you can provide a margin of productivity with the help of a hydraulic accumulator.
As for the pressure, we recommend choosing a pump designed for lifting water by at least 25 meters, if you decide to install it next to the spring.
If the equipment is installed at a distance of up to 10 m from the house, a pump with a pressure of 10 m will be enough, only normal installations will not work. The thing is that the suction capacity of most pumping stations is limited to a height of 9 m. In your case, the height of the water rise is (8 m + (80 m / 10)) - (1 m + (10 m / 10)) = 14 m, and this is only available for more expensive units with an ejection suction system. However, if you are willing to spend several times a large amount, you can easily pick up equipment with design parameters.
