DIY Ram Pump Obeys the Laws of Physics

Despite the claims of “free energy” on the title of the video below, this is not yet another wacky perpetual motion story. We here at Hackaday fully support the laws of thermodynamics, and we think you should too. But you have to admit that a pump that works without any apparent energy inputs looks kind of shady at first glance.

The apparatus in question is a ram pump, a technology dating back all the way to the 18th century. The version that [Junkyard – Origin of Creativity] built uses commonly available materials like PVC pipes and fittings. About the only things on the BOM that might be hard to scratch up are the brass check valves, which should probably be flap valves rather than the easier to find spring valves. And the only custom part is an adapter to thread the plastic soda bottle that’s used as an air chamber to the PVC, which a 3D printer could take care of if you choose not to hack a bottle cap like [Junkyard] did. The video below shows the impressive lift achieved just by tapping the kinetic energy of the incoming flow.

There, the Second Law of Thermodynamics remains inviolate. But if you still think you can get something for nothing, check out our roundup of perpetual motion and Overunity quackery.

44 thoughts on “DIY Ram Pump Obeys the Laws of Physics

  1. I expect that “free energy” does not mean in the perpetual motion definition, but rather that you don’t have to pay a power company or anyone else to put it the stream. Of course, someone will no doubt point out that it’s not truly free if you had to invest any money for any of the components for the pump and if your time is worth any money at all.

  2. There are lots of videos of very good pumps like this made for farmers/off grid homes where you have a stream of constant water lower than you want it and you need an easy way to pump a steady amount of water up to tanks.
    Your not wasting any water, as it’s water that would be going down the stream anyway. Your just tapping off the energy, to, for free, push the water up to where you want, often hundreds of meters.
    The full commercial ones are very reasonably priced and once set up, require little more than cleaning of screens and a yearly check. With modern polyurithane seals they also require no parts for something like 10 years.
    Plus they look cool!


    And Wranglerstar has a series on them showing install and setup.

    1. More than 12 minutes of something that could be shown in 30 seconds, and not a skerrick of useful info. Where is the feed line, and what head is it. Don’t waste your time watching this – you’ll get nothing (fortunately, I wasted only a minute thanks to being able to skip though it).

    2. The village I grew up in (in the UK) used one of these to pump spring water up to the nearby farm.
      I used to think that it provided the whole village, but now I think about it, that might not be true.

  3. Warning! Watching the “free energy” video posted above will result in sudden and unavoidable recommendations for more “free energy” videos for months. Viewer discretion is advised.

      1. You can block channels from showing up in your YouTube, but it can take a while to get most of them. I did the flat-earthers last week and that took at least an hour.

  4. I build one of these to get water up to my camp from a spring. I made the mistake of using the cheaper plastic 1 way valves.. They work for a while but end up sticking.
    I’ll be replacing them soon with metal ones.

      1. No. It works on static momentum and dynamic pressure wont work. It’s like the 5 ball newtons cradle. The basic principle is that both momentum and energy must be conserved.

  5. It’s simple enough in construction that I wonder if anyone ever built one in ancient times. Crafting the pipe and pressure vessel might be tricky, but not too bad compared to, say, Hero’s steam engine.

    Even as a one-off someone could have had themselves a wonder-of-the-world class magical fountain.

  6. Just a minor correction – the video appears to show SWING valves (ie, flap valves), not SPRING valves. So yeah. Although I can’t help but think they would be more efficient if they were laying flat, with the flap hanging, rather than upright.

    1. They need to be inefficient lol

      They let the water accelerate up to a fixed speed before they close. This is to gradually convert potential energy to momentum while the valve is open.

      When the valve closes the potential energy remains the same but the now moving water has momentum and the conservation of that momentum means the water has to go somewhere so it goes through the other valve because there is air in that chamber and it is much easier to compress air than it is to compress water.

      Once it is in the other chamber it is trapped by the second valve and it increases the pressure in that chamber. The pressure in the chamber increases incrementally until it forces the water up the output hose.

  7. It think the author of the video just made a mistake in titling the video. I think that they meant that this is an “electricity free” pump not a “Free Energy” pump. If you ready the description of the video, unless it was later changed, they write that this pump uses no Electricity or Motor, and it is clearly stated that it uses 4 cubic meters of water to pump 2 cubic meters to higher ground.

    1. He must have used a bonding agent because if he didn’t it would simply fall apart under the pressure. He probably just did a ‘dry’ run for the sake of the video.

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