Centrifugal pump flow rate selection
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The process design specifies Q=3 m3/h. Since pumps with such a low flow rate are difficult to find, is it acceptable to use a centrifugal pump with Q=10 m3/h as a substitute?
The flow rate is not small; the key question is what the head is? ? What medium is being transported
That flow rate is quite high; it depends on what medium you’re using and what the head pressure is.
There are countless pumps with flow rates much lower than this. What medium are you transporting, and under what operating conditions? For centrifugal pumps, use pumps with a DN25 diameter, an operating speed of 2900 rpm, and a flow rate of around 3 cubic meters.
Room-temperature acidic wastewater, 30 m head
We temporarily need such a pump, but it’s not convenient to purchase just this one unit; therefore we will use the old pump instead. The old pump has a flow rate of 10 m3 and a head of 30 m. What needs to be discussed now is this: if we use a pump with a flow rate of 10 m3 in a system designed for 3 m3, what problems might arise due to the inappropriate flow rate (which is too high)? These issues could affect the equipment used in the system as well as the achievement of the process objectives
Why not turn down the outlet valve a bit? It’s also a hassle to add a return pipe
If the valve is closed more tightly, the head increases, which is not good either for the pump’s operation
If the process design calls for 3 cubic meters, in practice a little over 2 cubic meters are actually used; with 10 cubic meters, there is significant waste, and the additional energy consumption is likely enough to cover the cost of buying a new pump in one or two years. 10 liters is certainly usable; it’s better to install a return line, otherwise the pump is prone to damage.
Sure, add a traffic pipe between the import and export sides.