Do Pumps Create Pressure or Flow?

Explaining how pumps produce both pressure and flow with some fun water demonstrations.

There’s a popular and persistent saying that pumps only create flow in a fluid, and resistance to that flow is what creates the pressure in a pipe. This video goes into some details about how two kinds of pumps work: centrifugal pumps and positive displacement pumps.

Practical Engineering is a YouTube channel about infrastructure and the human-made world around us. Hosted, written, and produced by Grady Hillhouse. We have new videos posted regularly, so please subscribe for updates. If you enjoyed the video, hit that ‘like’ button, give us a comment, or watch another of our videos!

CONNECT WITH ME
____________________________________

SPONSORSHIP INQUIRIES
____________________________________

DISCLAIMER
____________________________________
This is not engineering advice. Everything here is for informational and entertainment purposes only. Contact an engineer licensed to practice in your area if you need professional advice or services. All non-licensed clips used for fair use commentary, criticism, and educational purposes.

SPECIAL THANKS
____________________________________
This video is sponsored by Nebula.
Stock video and imagery provided by Getty Images, Shutterstock, Pond5, and Videoblocks.
Tonic and Energy by Elexive is licensed under a Creative Commons Attribution License
Producer/Host: Grady Hillhouse
Assistant Producer: Wesley Crump

[PracticalEngineeringChannel]

💧 Give me your best pump mantras. I'll meditate on the best one.

[JahLuvzU]

A good rule of thumb is: "If you want an accurate one-liner saying, don`t get involved in hydrodynamics".

[jakebrodskype]

As a professional engineer who worked at a water and waste-water utility for over 30 years, let me congratulate you for an excellent presentation. I would really like to see a future presentation on cavitation.

[dragonatorul]

"This isn't rocket science". I'm not a rocket surgeon, but I'm pretty sure pumps and fluid dynamics are a big part of at least designing rocket engines and fuel tanks.

[idatum]

This video operates where my interest curve and the supply curve intersect.

[jonas]

It actually is rocket science too. The big boy rockets all use pumps for propellant flow and thrust control :)) 0:32

[dralexmclean]

As a retired mechanical engineer, indeed pump selection for industrial applications is far from a simple task. Great video

[Exentity]

I’m a certified fluid power hydraulic specialist (CFPHS), and I really liked how you tackled this topic. Definitely showing it to my friends

[bartzrt]

"Not a great catchphrase, but it _is_ accurate." Spoken like a true engineer.

[JamesSimmons]

I'm an electrician. Everytime I hear it's not the voltage that kills you, it's the current, I slap them in the face and tell them it wasn't the velocity of my hand that hurt them, but the weight of it. Of course the real answer is it's the MOMENTUM of the hand i.e POWER that hurts you.

[shortstack]

Even though this is aimed a lot more at civil engineering concepts, for me who is studying chemical engineering, this channel is so informative to conceptualize and understand physical setups of a bunch of engineering concepts.
Thank you for the content!

[NickShabazz]

This was a really great video, thanks! Loved the graphs!

[krisb]

I work for a pump company, and I want to show this to all our customers who I swear don't understand pumps. Well done. I look forward to your future pump videos!

[HATECELL]

This is basically the hydraulic version of the discussion whether an electric source provides current or voltage. And as my university teacher likes to say: "what they have taught you in school might not be wrong, but the full story is a lot more complicated".

[t_c]

Your new vs old pump mantra is like the "money doesn't buy happiness" one. I revised that phrase to say "money can't directly purchase happiness or friends because they aren't purchasable items, but it can however make your life easier and facilitate many things that do make you happy and will overall improve your happiness versus your position if you didn't have it."

[miketrissel]

Boy do I wish we had an engineer like you, 20 years ago. I was an electrician that seemed to have absorbed/dumped into the water system where I worked. (Now retired) They had 4 vertical 1000 gallon / minute Deming pumps that outputted through 8” ID pipe, into a 14” header/collector pipe, sending water from a settling pond, ¼ mile back to the main plant. They kept adding more and more equipment, that needed cooling water, so the engineer kept adding pumps. No matter what he did, the pressure and the volume, ¼ mile away never increased. (Eventually up to 8 pumps) I tried to show him the folly of forcing more water through that same 14” pipe was futile, with an impeller driven pump, but the engineer looked at me as if I was a moron, till he finally got to see the amperage going down on each pump motor as other pumps were manually turned on. (Took 4 clamp-on's at once to visualize it)
If you would, show how an ammeter is a good tool to check and set up pumps, check wear on impellers, and the need to set the pumps at 100% load (rather than 70-80%), to get the best balance out of multiple pump systems. Some of the newer people to the field would benefit. Most people see pump curves, and just shrug their shoulders. Setting them up is fascinating though, especially when the mechanic foreman comes to you, with his budget for the year, and asks, which pump is showing the least efficiency, and you can show him with an ammeter, and a pressure gauges, which impellers are wearing the most, in parallel multi-pump systems. I’d be glad to feed you my notes, but it sounds like you have all you need.
Thanks,
Mike

[poisonpotato]

When I was in college I understood it as, pumps create pressure which gives fluid energy, difference in pressure causes velocity/flow.

[HobbyPackRat]

"this is the first of 2 videos... let me know if you want to see more". Grady, i'd watch a video on anything that you passionately explain. You explain complex topics simply with great demonstrations. Any subject is interesting in your videos. Keep up the great work.

[FowlerAskew]

Rewatching this video after measuring I-V curves for lots of small solar panels is really making the similarities between water and electricity stand out. Photovoltaic output is incredibly load-dependant (that's why we use MPPT controllers for all but the most basic solar setups) and the curve describing the output naturally looks a lot like the pressure vs flow rate graphs you showed of the pumps.

[andrewdaumueller]

Excellent video. It would have been nice to have this kind of thing when I was in college for civil engineering. Fluid mechanics was one of the harder classes for me to grasp. I doubt current students recognize how blessed they are to have access to content like this, bridging the gap between the academic concepts and how they manifest is reality. How about this for a catch phrase: "pumps don't create anything, but rather transfer energy into the system, which manifests in the form of flow and/or pressure".