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Flow rate after branch for filtration unit

Flow rate after branch for filtration unit

Flow rate after branch for filtration unit

(OP)
I would like any help in calculating the flow rate after a branch required for a side loop filtration unit. Currently the position for the system take a branch after the oil pumps and loop back into the system with a branch to a return line going to a surge tank.

The system has a 6" header after the pump at about 190 m^3/h (900kPa). After taking a branch of 6" the pipe would need to be reduced to 3" for flanged connection. I would like to be sure that the pressure drop of our design will allow the fluid to flow back into the system at the return line.  

Attached is a very crude sketch which may assist. You may see a better option than the design proposal in question.

Appreciate any help.

RE: Flow rate after branch for filtration unit

You need to have some idea of what the pressure will be over there where it says "return line", in order to figure the flow going in the branch from the pump to the filter.

We will design everything from now on using only S.I. units ... except for the pipe diameter.

RE: Flow rate after branch for filtration unit

(OP)
The pressure in the return line is known downstream at 580kPa. We have since been considering going back to the suction side of the pump or back to the storage tank which are 10kPag.

Will this be a matter of iteration to determine flow at the branch? Thanks.

RE: Flow rate after branch for filtration unit

Anytime you have more than 2 unknowns, of inlet pressure, outlet pressure, or flowrate of a pipe segment then it will be a matter of iteration.

It is likely that, if you want to protect against discharge line surges, going back to the suction is the wrong thing to do.  That simply raises the suction pressure, which will also tend to increase the pump's discharge pressure even more.

We will design everything from now on using only S.I. units ... except for the pipe diameter.  Unk. British engineer

RE: Flow rate after branch for filtration unit

Excess pressures are best vented through a relief valve, or a surge relief valve to some place out (or at least a place somewhat isolated) from the system you are trying to protect, ie. into a specific dedicated surge tank is best, or perhaps back to the tank the pump draws from, provided that is not a pressurized tank, where a flow into that tank will not increase either flow or pressure to the pump directly.

We will design everything from now on using only S.I. units ... except for the pipe diameter.  Unk. British engineer

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