selection of 2 pumps working in paralel pipe
selection of 2 pumps working in paralel pipe
(OP)
Hello, I would like to know the procedure for selecting 2 pumps to work in paralel both recirculating half of the total flow.
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selection of 2 pumps working in paralel pipe
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RE: selection of 2 pumps working in paralel pipe
RE: selection of 2 pumps working in paralel pipe
RE: selection of 2 pumps working in paralel pipe
As GMCD mentioned, the flow delivered by the pump is highly system specific.
If one pump alone operates to deliver 100 gpm actual flow ( not the name plate flow), adding another pump in parallel in a high static head system ( such as an over head storage tank) the flow may be 20 to 35% more. If the system resistance is pure flat,i.e. zero friction loss, the new flow can be almost 100% more.
On the other hand, for a friction head predominant system, the increase in flow by adding another pump in parallel can be very small, say 10 to 20% only.
Could you tell us more about your system?
Dinesh
RE: selection of 2 pumps working in paralel pipe
Total system head estimated= 53.5 ftwc
Total flow needed= 960 gpm
I pretend to use 2 vertical in-line pumps (parallel).
RE: selection of 2 pumps working in paralel pipe
respectfully
RE: selection of 2 pumps working in paralel pipe
Get your pump curves for your intended pumps. Plot the system curve on the chart. Plot a parallel pump curve where the flow at any given head is doubled. At the design head and flow, each pump will be supplying half of the flow. If only one pump is operating the flow will be at the intersection of the single pump curve and the system pump curve. This may be in the range of 60% as GMcD said.
You can select pumps online at http://www.bellgossett.com/selectpumps.stm
you must register first however.
RE: selection of 2 pumps working in paralel pipe
Your system is a friction head predominant system, static head in a closed loop system can be assumed to be zero.
From the description, I understand that the resistance offered by the system to a flow of 960 gpm is 53.5 ftWC. If both pumps are going to be operated together, each pump can have the specification of 480 gpm and 53.5 ftWC. Plus some margins.
If you operate only one pump out of this, the flow will be much higher than 480 gpm, say 700 gpm and a pressure of 29 ftWC, depending on the pump curve. This could overload the motor or trip.
RE: selection of 2 pumps working in paralel pipe
I have seen a system similar to that you have described, except the fact that it was intentional heating of water by keeping the pump at shut off. This was a vapour absorption chiller test bed of a manufacturer. The artificial heat load for chiller was provided by the churning of water in the pump.
Dinesh