May I ask that the water from 3 pumps is combined into one main pipe, which then splits into 4 branch pipes?
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Three pumps (2 in use and 1 as a backup, with variable frequency drive) supply water to a single main pipe, which in turn divides into 4 branches. Each branch requires its own flow rate to be adjusted (regulating valves and flow meters are installed in each branch). The 4 branches do not need water at the same time, which leads to fluctuations in flow rate and pressure; even if just one branch is turned on or off, it affects the flow rate of the other 3 branches. How can flow rate stability be achieved? ?
Weren’t those 3 pumps of yours equipped with variable-frequency motors? Frequency conversion and pressure interlock are sufficient; maintaining a stable pressure is all that’s needed. The pipeline ensures pressure, which in turn ensures flow rate. The instantaneous disconnection of one branch certainly has an impact on the other branches, but through frequency conversion regulation, a new supply balance can be established. Moreover, in a centrifugal pump, pressure and flow rate are related to each other.
For 2 variable-frequency pumps, one should be operated at a fixed load while the other has its frequency adjusted according to pressure; this approach should result in greater stability. If both pumps use variable frequency control, it adds an additional variable, which instead leads to instability. Of course, this assumes that the demand does not fluctuate too greatly – for example, a drop from 100% to 30% in a short period of time still results in some level of fluctuation. In such cases, it is better to restructure the system, such as by using 3 pumps with two sets of outlets (any one of the 3 pumps can supply fluid to both sets of outlets), which may reduce fluctuations by minimizing the number of variables involved
A pressure tank is connected in parallel to the outlet main pipe of the water pump; the pressure of this outlet main pipe is then monitored, and the speed of the variable-frequency water pump is controlled based on that pressure in order to maintain the desired outlet pressure. In this way, no matter how many branches there are at the outlet, they do not affect each other. For the selection and design of a pressure water tank, you can find a manufacturer on your own to get a quote.
I think adding a large return pipe would work, but it would waste energy
It’s possible to set a variable frequency, but I wonder why two large pumps aren’t used, one in operation and one as a backup.
There are too many variables, making it difficult to control.
Normal usage requirements can be easily met; extremely extreme and demanding levels of stability are not achievable
To be precise, the manufacturing process isn’t likely to be that advanced at the moment