Good afternoon, dear guests and subscribers of the "Build for Myself" channel!
In this article I would like to describe how to choose the right surface-type automatic pumping station to supply water to the point of water intake from a well or from a well.
The market offers a lot of pumping stations, but you should understand which one will satisfy your needs. The station includes an automatic pump on / off switch, a pump, a hydraulic accumulator and a pressure sensor.
All that is required of the owner is to bring the pipe from the well and connect the pipe leading to the water supply system.
But, it is important to know the following rule for all stations: surface-type station raises water from a depth to its installation site by no more than 8-9 meters. This is due to atmospheric pressure. When the pump is turned on, the station displaces the available water from the pump chamber (snail) and a vacuum is created at the inlet, thus Thus, water intake occurs by self-ascent to the pump due to vacuum (at the inlet, the pressure becomes lower than in well). And, if the lift height from the mirror is more than 8-9 m, water will not be supplied to the pump, there will simply not be enough pressure.
By the way, every 10 meters of rise is equivalent to 1 atm., But 10 meters are ideal conditions without pipe resistance. Considering this factor, the station is able to take water only from a depth of ~ 8-9 m.
So, for the choice, you need to evaluate the following conditions:
1. Know the height of the water rise before and after the pump.
2. Know the required working pressure (for irrigation, up to 1 bar is allowed, for the operation of household appliances - at least 2 bar).
3. Know the length of the horizontal section of the water supply.
Each pumping station has its own capacity and from the factory is completed with a product passport, which illustrates a graph of pressure-flow characteristics. The capacity of the station must ensure the total flow rate of the simultaneously switched on points of water intake, which are presented in the plate below (l / s. can be converted to l / min for convenience. multiplying the value by 60):
Below is an example of a flow-pressure graph, where the Y-axis is the head, the X-axis is the flow (as an example, 3 curves are shown for 3 pumps of different capacities):
Example
The pumping station is located 5 meters from the well (L = 5m.). The lifting height from the well is 4 m, i.e. according to the figure H = 4 m. According to the rules of hydraulics, every 10 m of the horizontal section of the pipeline is equal to 1 m of rise due to the resistance of the pipeline.
Thus, the total lifting height is H + L / 10 = 4 + 5/10 = 4.5 m. Those. the condition that the height should not exceed 8-9 meters, - performed!
Important!
If the pumping station is installed in the house on the upper floors, then the height from ground level to the station is also added to this formula.
With the input sorted out, now there is a question of providing the necessary pressure for domestic needs.
Imagine that we need to provide sufficient pressure to the water supply system for several points of water intake, presented in the plate above. I have added up the values of the first two cbm / h positions. and received 1.4 cubic meters / hour. Thus, we need to choose a pump that will provide a productivity of ~ 1.5 cubic meters / hour at a pressure of at least 2 atm.
Referring to the graph of pressure-flow characteristics. Let me remind you that this graph is drawn on the pump tag or in the product passport. As it turned out above, we want to get 1.5 cubic meters / hour from the pump, so we plot this value along the X-axis in the form of a vertical axis and lead to the intersection with the pump curve (green line).
Next, project this point onto the Y-axis (blue lines). We get the head of the first pump 15 m, the second 22 m, the third 28 m, so the pressure created by the pumping stations will be 1.5, 2.2, 2.8 atm. accordingly, with our requests for a productivity of 1.5 cubic meters / hour.
What's important here? This pressure will be at the pump outlet, but we also need to transport water to the sources of consumption. Therefore, every 10 m. Of water rise, 1 atm will be subtracted from the obtained value. For example, we have chosen the second unit, which gives us 2.2 atm. and we supply water to the second floor, which is about 3.5 - 4 m. From the value of 2.2 we subtract 0.4 and we get 1.8 atm.
Consequently, the second pumping station is also not suitable for us, since the optimal pressure for domestic needs is 2 atm, so there is only one choice - option No. 3.
Author's advice
Before you go to buy a pump, in the hope that the seller is not stupid and will certainly help with the calculation and with the choice of the station, then no - it is better to do it yourself calculate the performance in advance and choose a product line using the Internet in order to go already aiming at purchasing with luggage knowledge. Fortunately, all pressure-flow characteristics are already presented on the network.
I hope this article was useful to you. Thanks for attention!
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