Do Pumps Create Pressure or Flow?

544K weergaven257

    Explaining how pumps produce both pressure and flow with some fun water demonstrations.
    📺 For a LIMITED TIME get CuriosityStream AND Nebula for 26% OFF!

    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 NLname 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!

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    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.

    This video is sponsored by CuriosityStream.
    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

    Gepubliceerd op Maand geleden


    1. Practical Engineering

      💧 Give me your best pump mantras. I'll meditate on the best one. 📺 Don't forget to jump on this great Nebula/CuriosityStream deal.

      1. Deeksha Rathour

        Please make more videos on different types of pumps

      2. greenspiraldragon

        It won't work without water.

      3. electric

        The amount of flow a pump creates is based of the conditions in which it is placed

      4. Blake Lonsdale-Cook

        Primed pumps promptly provide persistent pressure, persistent pressure permitted to propagate provides pouring particles.

      5. Nathan keller

        Pumps create flow that becomes pressure

    2. Harith Za'im

      hi. im developing an agriculture irrigation system. how can graph the system? do i need several pressure gauges at different locations?

    3. HeerYanus

      Wisdom taught me when doing work in the process and energy department of my university: If your setup doesn't leak, its a bad setup. Some very good setups in this video :)

    4. Jacob Strutner

      Every pump has flow at a given pressure. Even common rail diesel technology is this way at 28,000+ psi

    5. Ben Simpson

      I am a firefighter and I have been really enjoying your pump and hydrodynamics videos. Helping me understand some fundamental concepts that inform my pump ops training.

    6. Carlos Raúl Gómez

      Pumps impart kinetic and potential energy, how much of each depends on the system

    7. peep39

      "Do pumps create pressure or flow?" "Yes"

    8. EssJay1095

      I've always said that an energy difference (pressure, voltage, temperature) drives a transfer of energy (flow, current, heat) while there is a resistance to the flow. Then I just look at the extremes of total resistance (pressure max, flow 0), and zero resistance (flow max, pressure equalizes/voltage collapses to 0). So with that said, I guess it only makes sense that whether it creates pressure or flow depends only on resistance.

    9. Lizard King

      Hmm.. assuming a curve from 3 data points is a bold assumption

    10. Super Hiro

      One mantra I have to tell customers is “do not mix metals!” because of leeching. Of course this is in elemental analyzers.

    11. Petair23

      I love your work. If I was a TV exec, you'd be the next Mike Rowe. Your voice and manner of speech are so welcoming and very pleasing. Not to mention, you're super smart and have a gift for explaining whatev in such an understandable and factual way. Plus, you're covering topics that, for me, just hit home in such a good way. I'm curious about the world I'm living in, and you give a whole lotta answers. Please keep up the fabulous work! Do you have a Patreon or Merch?

    12. spelunkerd

      When vehicles age it is common for oil pressure to sag, and then comes the inevitable question, is the pump clogged or failing. More often than not, the cause is reduced peripheral resistance from engine wear. Flow is increased, not decreased. Too bad it is so difficult to practically measure the volume of flow, it would make diagnostics on cooling systems, sprinkler systems, and oil delivery so much more interesting.

    13. Anthony Nichols

      Forgive my painting with overly colorful language, but this channel is pretty much nerd-porn... Fascinating subject matter, and you do a great job of breaking down the concepts you're explaining. Thank you sir!

    14. teenflon

      Makes sense, similar to electronics, a battery doesn't produce a fixed current, it depends what resistance its connected to as to how many electrons will flow

    15. Ken More

      Well, that notion is stupid because how can a pump create flow without creating pressure?

    16. Kevin A.

      What is crazy for many to see is that if you put a pressure gauge between the pump outlet and gate valve, as you close the gate valve the pressure goes up. Okay, that is normal but look at the amp meter! It goes down! It's because the work the pump is doing is moving water, but when you stop the flow, you're also stopping the work. The pump impeller is just free-spinning without a load. I've won many bets on that one! The normal thinking is that if the pressure goes up so does the amps. Just like the fans, take their work away, you take their load away.

    17. Brad McEachern

      As soon as i saw the VSD, i knew this was going to be good =)

    18. Misael Moreno Luna

      I enjoy watching your videos, I find them very informative! I came here to watch the video, and in the process, I just signed up for a year of Curiosity Stream😂😌🙂🧐

    19. Kyle Alexander

      I wanna know how the pumps change when theyre pumping into a 95% full 495k gallon tank. Specifically 25 hp pumps.

    20. Kyle Alexander

      As someone who has moved a pretty large volume of wine and juice for wine i can tell u this is all true. If u suck air u lose pressure

    21. Michael Verde

      Booster pump systems will run and then shut off based off of pressure readings. When the pumps shut off, no ones using water and all components are working right, the pressure will remain in the system. Pumps made that pressure baby

    22. KeijoAmbersson

      If we go to machinery hydraulic systems, we start to get variable displacement pumps that actually do determine how much flow they provide at any given time. But the displacement of them in given moment is usually controlled by the system pressure. Certain pressure threshold is reached, and pump displacement is lowered to lower the flow, and in turn lower the pressure. The pump is controlling itself, within the system parameters. I sometimes scratch my head and wonder what kind of person originally came up with this. It's brilliant and kind of silly at the same time.

    23. greenspiraldragon

      More videos about pumps.

    24. Austin Schwebel

      I'm upset you didn't bring up the huge change in pump flow if you change RPM from 2/4/6 pole and along with impeller trim relative to the pump curve.

    25. Dallas Arnold

      I have to argue the point. How much pressure is there at the point of discharge from the pump ? Well you can not measure that without creating some type of restriction or resistance which is actually where the pressure is created. If the fluid discharges into a pipe it is already incurring a restriction.

    26. Park Nelson

      You just summed up ME 460 in 10 minutes.

    27. Mr. Kips

      As an electrician, I laugh when someone says “ It’s not the voltage that kills you, it’s the current”. ElectroBOOM has also covered this subject.

    28. sandesh honmane

      If the motor RPM can be varied then positive displacement pumps can also deliver variable flow.

    29. Al To

      Creo que la tecnología de los taladros de aire podría mejorar las motocicletas pues desde ser mejores y más fuertes explosiones a usar hidrógeno en explosiones de combustible, sino el principio de motores de aire por compresión y no contaminantes, junto de eléctrico a aire comprimido o de esa tecnología a ser en vez de taladro para concreto también en motocicletas y transferencias de energía, eléctrica a neumática o usar como cámaras que soporten hidrógeno de combustible, según quieran opciones de tecnología sugerencia.

      1. Al To

        Las cadenas de transición que usan bicicletas y motocicletas, creo que se puede mejorar, con diseño de ciertos animales vertebrados como representar en una cadena de metal y engranes, la tecnología de hecho de engranajes imposibles aplicada a cadenas de transición que permita poco desgaste y fricción en cadenas que parecen engranajes alien, pues casi no fricción an dientes sino empujan como los videos de engranajes de cubos de rugbik con engranes, engranes no convencionales y hasta de formas de óvalos y no círculos para ser más dientes del engranaje y empujar más que friccionar y desgastar en circular, incluso las orugas de tanques servirían en parte en cadenas de transmición, también la tecnología de rotulas de caderas o huesos por forma de sus uniones en serie asemejando dientes de engranajes, sugerencia.

    30. John Morgan

      Ok, the experiment at 2:52 is such a wonderous experimental demonstration to be able to find with ease. Bless your heart. Now, what happens when the experiment is done using different gauges of tubing? Or just someone tell me what would happen?

    31. Renegade50deuce

      Pumps create neither pressure or flow, they provide energy. Pressure and flow being a consequence of that energy.

    32. bassamatic

      the pump creates a pressure DIFFERENTIAL, creating flow from high pressure to low pressure.

    33. Alexander Wlad

      If this video reaches 40k likes Grady will shoot a video on him doing 100 chest pumps

    34. Tonic Artos

      If you want to remove the pressure from the equation, don't you to separate it into positive flow and negative flow? As in, you have a degree of slip (negative flow) in the centrifugal pump dependent on the potential in the body of water in the output.

    35. Amit Borkar

      Make demonstration of multiple pump how effective it is.. Will increase flow or head with same head pump if placed in parallel or series

    36. Sagan The Khajiit

      "It's not the voltage that kills you, it's the current" kinda sounds like "it's not falling that kills you, it's hitting the ground"

    37. Ticked Off Sheikh

      Great video. I love the subject myself. Can you do a comparison between centrifugal pumps vs Archimedean screw type pumps? I have seen a drainage centrifugal pump with a bore of 60 inches delivering 600 tons per minute. Which is more efficient for drainage applications? Thank you in advance.

    38. Blake Lonsdale-Cook

      Primed pumps promptly provide persistent pressure, persistent pressure permitted to propagate provides pouring particles. If you're willing to give up the alliteration at the end, then instead use: Primed pumps promptly provide persistent pressure, persistent pressure permitted to propagate provides flow.

    39. RenchesAndSords

      por que no los dos

    40. BaronZ

      As an electical engineer this rings a lot of bells. The behavior of diodes/transistors and motors can be characterized through intersecting functions of intrinsic and extrinsic behavior of the system in response to a change in voltage/current.

    41. Riku Lappi

      Please more videoes on pumps! Pleeeeeees! Here in Finland most folks own a fraction of a family summer cottage by a lake or have access to one through friends or access is a fringe benefit provided by your employer. Practically every cottage with electricity has a fixed water pump, often submersible ones for winter when the primary pump and pipes are empty and dryed, consequently inoperable. (I recall people in Texas had pumps and pipes destroyed by freezing water recently😭). The video was great. I will pass it on to my kids. Cars have multiple pumps, aquariums have pumps, an air compressor is a pump. Pumps are cool. However, elementary understanding may save you a lot of money...

    42. meowmeowbobo

      Erm so basically impeller pump obey ohm's law? The flow is depended on the pressure (pump characteristics) and reaistance(pipes)

    43. 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.

    44. Stefs Engineering

      0:30 it isn't rocket science, but a large part of it for sure. Take for example the new SpaceX booster that has to distribute fuel and oxidizer to 29+ engines at quite a significant rate.

    45. warren osborne

      Thank you for your very clear and concise explanation of physical properties without going over the heads of the majority of viewers. I don't think that it would be detrimental to slip in just a bit of math. (gently)

    46. Sylvia Duke

      May father was a steam engineer during WWII and worked for Memphis, TN Light, Gas & Water over 25 years. I got to see him check the plumps every few minutes and walk the plant! He was very careful about this job. He tried to explain it but I was only 7 at the time.

    47. chris thorney

      would a positive displacement pump not slow down as it reaches higher head heights, because it would slow down until the motor driving it stalls out and cant pump against so much head pressure, so thus its flow rate would decrease as head height increases because its pumping against a higher backpressure

      1. Practical Engineering

        Depends on the motor and drive. Many pumps use synchronous motors that can’t slow down

    48. thokim84

      Pumps suck.

    49. MrBabyBitch666

      It is absolutely the voltage that kills you

      1. Blake Lonsdale-Cook

        No, it isn't. It's the wattage that kills you. Wattage is a function of amperage and voltage in accordance with Ohm's Law.

    50. Earl Lighthill

      Where were your safety glasses for this demonstration?

    51. G0sentrick

      "Tide goes in, tide goes out. You can't explain that." - Bill O'Reilly

    52. Kent Freeman

      One way to look at this is if the pump is turned off is there any system pressure?

    53. Ames Doe

      thanks for the graphs about the different curves! i also appreciate the video editing. you're a wonderful resource, Grady.

    54. Steve Clayton

      how about a show on PD pumps? blackmer and corken pumping a pressurized gas like propane and or NH3

    55. mbc1994

      Could you make a video of Water Pressure Regulator Valves, and espceially how they work, in detail.

    56. DJ Deckard Cain

      Grady! Have you thought about doing a video about the Gigapress that Tesla had Idra build for them? That thing's a modern engineering marvel! 430,000 kilonewtons of force!!!!!! That's over 1,300,000 lbs of force!

      1. Blake Lonsdale-Cook

        I'm very curious as to what it's used for now.

    57. A B

      A. What is the best water pump design & motor to use to do the following: 1. Pump water from a lower elevation to a higher elevation using a battery operated pump (e.g. ~7 ft H via .5" ID tubing) 2. Maintain the proper water flow rate based on the user's adjustment of H & C water faucets (e.g. .5 gpm to 3.5 gpm) 3. Minimize battery energy usage at various user defined water flow rates B. What type & size pump would be ideal for such an application? C. Would a one-way check valve reduce energy usage or is that unnecessary? D. Is a variable speed pump ideal or would a less expensive fix speed pump be a better choice? E. What would be be an ideal pump (brand & model) for such an application?

    58. It Has Been Written

      I’ve had a lot of friends who are engineers, i myself am a mechanic, and I always smile when i see Grady puts little eyeballs on the action pieces knowing full well how special it is for an engineer to humanize things for the rest of us emotional non-Vulcans. It’s a special breed who can bridge that gap. 🖖🏽 And amazing how much of a difference they make! 👀

    59. cesar ortiz

      The cooperative mouth densply trouble because meeting spectacularly happen excluding a embarrassed chick. racial, lying loss

    60. BlueParadise

      I have enjoyed your channel, would you do a video on lifting water. Pulling water up via suction vs pushing water via pressure. single stage lift, vs multi stage lift. 1" pipe vs 4" pipe. Love to see it. Thanks

    61. Grass Geese

      Wow, the comparison to voltage/current was actually very helpful for me!!! I'm learning about electricity at the library lately, and i am shocked (lol) at how similar flow of electrons and flow of water can appear

    62. seasong

      I hate it when I accidentally choose the wrong pump for my city's water supply 😭

    63. Migueldeservantes

      Love the opening statement do pumps create pressure or flow? immediately remind me of the engineering school saying that wings lift a plane creating vacuum that sucks the plane upwards!! then the argument with the other guys saying that its actually higher pressure on the bottom of the wings!! and as you mentioned with current & voltage.. you can't have one without the other....

    64. gaurav rade


    65. William

      Shortened motto, "It depends..."

    66. Hans Ulrich Johner

      The Bernoulli equation describes the relation between pressure and flow nicely!

    67. Duncan Harris


    68. Nick Lewis

      Awesome video! I am a project engineer for a large diameter(54” into 92”) sewer project where we bypass 30MGD. I just went through learning all this and this video does a great job simplifying a complicated topic.

    69. Maggie Jetson

      They are the same thing, pV=nRT.

    70. John Abraham Gargantiel

      i think your float is installed upside down: your flowmeter

    71. roger brandt

      Can’t believe there’s only 2 million likes, guess the people nowadays don’t care about learning.

    72. Andy

      Without watching the video, the answer is simple: Pumps create pressure which causes flow once resistance (friction, gravity, etc) is overcome.

    73. Friday Californiaa

      You have to create a video about water cooling in computers. I feel like there are many mistakes made in this domain about pumps =)

    74. Sander Zewald

      It's not the voltage or current that kills you, it's the Wattage.

    75. stampy Dragon

      I’d make a pump from one way valves using flow from a river to create the operation

    76. LLiC

      Put it in Spanish too, please

    77. Aaron Klein

      Just saying Grady I think we enjoy just about anything you think might be interesting. Loved this one.

    78. rupe53

      To make it simple, pumps create pressure differential. It's the difference between inlet and outlet that causes the fluid to flow. What most don't bother to figure is the plumbing (both distance and size) plus change in head pressure / height also figures into this pressure differential. Longer pipes and smaller pipes have more resistance to flow. Change in height of the inlet or outlet can also change resist or increase flow rates. Bottom line is it's not all about the pump itself. The entire system design is part of the pump's capacity.

    79. pmailkeey

      Grady, feel free to answer this one in a video: Why do people with hydraulic drives refer to them as hydrostatic systems when clearly fluid motion is dynamic.

    80. pmailkeey

      CLEARLY :) 0:09 pumps create pressure. The pressure they create CAN create flow. Next question ? Perhaps one a bit harder ?

    81. Broc Luno

      Would very much appreciate an examination of a Berkeley Jet Pump in a boat. Near zero head, lots of volume, rising pressure curve against a fixed nozzle based on RPM. How to extract maximum boat efficiency? More discharge velocity? More discharge volume? Let's say target RPM is 5,000 - available HP at that RPM is 450, boat is planing hull at anything above 20 mph ... Berkeley Jet Pumps are considered mixed flow pumps, not entirely radial, not entirely axial ... Any ideas ??

    82. Dragon Curve Enthusiast

      Great video as always! Thanks Grady! :-)

    83. Stephen Stromsness

      First video of yours I've watched very informative and well done. Really appreciate it.

    84. Fun Day Sailing

      At 6:30 you added resistance to the system by the way of head. The weight of the water sitting in the head tube was the resistance to flow. Enough so that the pump was unable to overcome the resistance to flow. I get your point that pumps and restrictions are closely related and you need a pump that can overcome the resistance in a given system but the pump is not the source of pressure, especially not in this example - it created flow right up to the point to when it was used beyond its capacity and stalled out, unable to create any more flow against the pressure build up.. You can only have pressure within a container. The pressure in the system was the weight of water contained within the head tube. In this example the pressure and head height are directly related because the pressure is the result of gravity pulling the water back into the container (or pipe).. More head = more pressure and no head = no pressure. If you exchange the pump for a closed valve in this example there is still the same pressure in the system, thus the pump is not creating any pressure. I stand by the saying that pumps create flow not pressure, but I think it would be more accurate to say that pumps impart kinetic energy into a system and it is the resistance within that system that converts the kinetic energy (flow) into potential energy (pressure). For you electricians........A generator (pump) doesn't create light, it creates electricity - it is the light bulb (resistance) that converts the electricity into light. Thoughts?

    85. Greta Thunderer

      Positive displacement pumps don't always have a linear characteristic curve. I work in the healthcare industry and we use positive displacement pumps for our detergents for surgical instrument reprocessing. After installation they must be calibrated because the head and pipe length both have direct impacts on how much detergent is pumped per revolution.

    86. Raymond J

      YES !

    87. Dead Skin Rippers

      By virtue of pressure drop created by the pump rotor blades flow is produced. It's like understanding how u suck water from a straw. Unless there is a pressure difference between atmosphere and suction from ur mouth no flow will take place.

    88. J-max FromOR

      Thanks Grady for interesting video. In summary, sounds like all pumps create pressure, and how much flow, if any and which direction, depends on the input and output systems of pressures, energy losses in pipe friction, valves, and corners, and in other pumps, turbines, etc.

    89. Robert Kesselring

    90. CAD Thunkin

      As a lift station designer, I know the big fail is when the pump is lifting very little, and the pump spins away. (called flooded suction) The power consumption is highest when it spins the fastest. You have to be careful the electrical system can handle that, or it trips and you can't do what seems the simplest thing, lifting water no elevation. So it needs more power when making more flow. Therefore, its a flow machine :)

    91. Ron Masters

      Had a long, confused discussion over lunch one day with a friend who needed to pump water into a very high reservoir, and was trying to arrange multiple pumps. This clarifies the whole problem.

    92. Robin Blom

      Love your vids, keep up the awesome work!

    93. Jim Holmes

      How come the 300,000 volt spark that jumped from the Van de Graff generator didn't kill me?

    94. MalcolmCooks

      "It's not the force of the gun that kills you, it's the speed of the bullets!"

      1. 44R0Ndin

        More correctly, "It's the momentum of the bullet over the short time period of the interaction that delivers a lot of damage to your body". Bullet proof vests allow the interaction between bullet and flesh to happen over a longer period of time without causing permanent damage to the flesh, and ceramic body armor plates allow the bullet to break them in a controlled manner to dissipate the kinetic energy in the incoming projectile entirely before it reaches the flesh.

    95. Jomelle Samuel

      Do more pump vids

    96. Jasper Frith

      As a Civil Engineering student trying to get through my hydraulics modules, please come lecture us, our current lecturer is just obsessed with is postgrad students :/

    97. Rohan Grant-Dawes

      Brilliantly explained. Always love your videos. Left feeling very satisfied. Amazing work

    98. LegitGopnik

      Teachers use water flow as an analogy to teach electricity easier. I don't see anything easier about water.

    99. Nine Horse Hitch

      . . . To be nit picky and technically correct, shouldn't the focus be on how the pump applies a force on the fluid? Centrifugal pump applies a force on to the water by accelerating it outwards from the center of the pump this created a suction on the water in the suction. For a centrifugal it created the flow first. Positive Displacement pump draws the fluid in. It is creating a pressure to suck the fluid in.


      I used to sell Industrial pumps and tanks and ironically we didn't delve much into centrifugal pumps. Positive displacement pumps (namely Viking internal & external gear pumps were our bread and butter) but I'm glad because it's much easier to do one or the other, dealing with both can be quite the headache!