The head of two pumps in series.
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The feed pump has a head of 30 meters, a flow rate of 30 cubic meters, and a power rating of 7.5 kW; it is used to supply fluid to the equipment’s feed pump. The equipment’s feed pump has a head of 18 meters, a flow rate of 170 cubic meters, and a power rating of 22 kW. The two pumps are located on the same level, 20 meters apart from each other. The equipment is situated 8 meters above the feed pump, and there are 2 meters of piping inside the equipment. The required pressure is 3 kilograms per square centimeter. What will be the total head when the two pumps are connected in series? Can it meet the equipment’s pressure requirements?
Will the pressure from the feed pump place a load on the circulation pump?
When the flow rates of two pumps are different, the one with a higher flow rate should be placed at the first stage, while the one with a lower flow rate should be placed at the second stage. The difference in flow rates between your two pumps is quite significant; if the first pump is not connected to a bypass, it will operate at a lower flow rate, which can lead to excessive vibration and damage to the equipment. Readjust the flow control of the feed pump for the equipment operating in series; a head of 48m should be no problem.
The flow rates of the two pumps differ too much; it is not suitable to connect them in series
Thank you! The liquid inside the equipment still needs to be circulated using the equipment’s feed pump; can it be fed into the equipment’s pipes through the pump that is not in use? Start the equipment pump only when there is enough liquid inside the device.
The parameters of the two pumps differ too much; it is not recommended to connect them in series, as improper operation can backfire
The feed pump has a flow rate of 170 cubic meters, while the supply pump has a flow rate of 30 cubic meters. Are you sure the feed pump won’t get empty? Putting that aside for now: a pressure of 3 kilograms is required, which corresponds to a distance of 30 meters; the vertical height difference is 8 meters, and each elbow adds 0.5 meters, so in total we have 38.5 meters. Let’s assume a pipe loss of half a meter, giving a total of 39 meters. The head required for the feed pump is 18 meters, while that for the supply pump is 30 meters. The flow rate is 30 cubic meters per second, and the distance between the points is 20 meters – this is the distance over which the fluid needs to be transported to the inlet of the feed pump. The feed pump has a capacity of 170 cubic meters per second; it seems that there won’t be much inlet pressure left. The outlet pressure will probably be around 18 meters, which is not sufficient.