Two Pumps on one system flow question

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Discussion Overview

The discussion revolves around the flow characteristics of a hydraulic system utilizing two positive displacement pumps, each rated at 22.5 gpm. Participants explore whether the combined flow rate of the pumps would be 45 gpm or remain at 22.5 gpm, considering the system's configuration and operational parameters.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether the flow rate from two pumps in a parallel configuration would double from 22.5 gpm to 45 gpm or remain at 22.5 gpm.
  • Another participant confirms that the pumps are positive displacement and self-compensating, capable of producing 22.5 gpm each at maximum demand.
  • A participant inquires about the controlling element that dictates the demand signal for the pumps, suggesting that pressure drop in the system prompts the pumps to compensate for increased demand.
  • It is proposed that running the pumps in parallel would yield a greater flow than 22.5 gpm, provided they operate at the same pressure of 3,000 psi.
  • Another participant asserts that the two pumps can deliver a combined maximum flow of 45 gpm at the specified pressure.

Areas of Agreement / Disagreement

Participants express differing views on the flow rate, with some asserting that the flow will indeed double to 45 gpm while others maintain that it may not. The discussion remains unresolved regarding the definitive flow characteristics of the system.

Contextual Notes

Participants reference the need to consider system components such as valves, restrictors, and pipe sizing, which may influence the actual flow rate. The discussion does not resolve the implications of these factors.

Who May Find This Useful

Individuals interested in hydraulic systems, pump configurations, and fluid dynamics may find this discussion relevant.

J_Rob
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I am hoping this is the right place to post this.
I have a hydraulic system that uses two pumps. Each pump is capable of producing 22.5 gpm. With out taking into account the different valves, restrictors, and pipe sizing, my question is, does my gpm double to 45 gpm or stay at 22.5? the pumps are not in line with each other, just provide fluid flow and pressure to the same system.
the way I was taught was I only have the 22.5, recently some guys have been saying we have 45. I can't find any laws or theories to explain this. thank you for all the help
 
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These are positive displacement pumps ?
 
Nidum said:
These are positive displacement pumps ?
Yes positive displacement. the pumps are self compensating, variable volume. at max demand each pump can produce 22.5 gpm
 
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What is the controlling element (i.e. flow, discharge pressure etc) that provides the demand signal to each pump?
 
JBA said:
What is the controlling element (i.e. flow, discharge pressure etc) that provides the demand signal to each pump?
As the pressure drops in the system the pump will self-compensate for the increased demand.
I think I have found my answer to the original post. Running the pumps in parallel is going to give me a greater flow than just 22.5 gpm as long as they are operating at the same pressure. which in this systems both pumps operate at 3,000 psi. any additional thought would still be appreciated.
This website really helped.
http://www.engineeringtoolbox.com/pumps-parallel-serial-d_636.html
 
Basically, the two pumps will act in concert to deliver up to a combined maximum 45 gpm @ 3000 psi system delivery demand level.
 
J_Rob said:
This website really helped.
Yes, that's an excellent site...
Another good one is... here .

ps:
I've always considered it somewhat strange, that anybody would want a pump or motor that was... bent !

Just kidding... :oldwink:
 
Last edited:

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