An Improved Simple Hydraulic Ram Pump




Introduction: An Improved Simple Hydraulic Ram Pump

About: general bloke type of tinkering

Based largely on the BreurRam pump developed by Gert Breur, my version features an alternate component layout.
The simplicity of the original design is due to incorporating the air reservoir, which absorbs the hydraulic shock, into the outlet tubing, with only 2 check valves being used, one of which needs to be modified.

The hydraulic ram uses pressure pulses from the closing of the waste valve to pump a small amount of water out of the discharge/outlet check valve.

My question is, can the pulses be better managed for increased efficiency?

The following documents my ram pump build and subsequent testing.

Step 1: Theory and Method

The traditional ram pump has the inlet opposite the outlet valve with the vertical waste valve connected via a T piece in between. A typical setup is the Clemson University version, in the numbered diagram the inlet is at the right at #1, waste valve at #4 and one way outlet check valve at #5 with #15 depicting the air reservoir. During the working cycle it can be seen that the pressure pulse will be reflected by the closing valve into the bottom of the T-piece and dispersed equally back upstream to the inlet as well as downstream to the outlet valve.

I suspected that directing the pressure pulses in a more focused manner toward the outlet check valve might result in better pumping efficiency.

My method of achieving this was to place the outlet opposite the waste valve so as to receive the pressure pulses more directly. One solution was to place the waste valve at the end opposite the outlet and have the inlet between the two, entering either from above or the side, I settled on a side inlet for device stability. The pulses from the waste valve would be reflected via a modified 90 degree elbow fitting to the outlet.

I built two 25mm (3/4") devices, a traditional config and my custom one, using interchangeable check valves reduced build variations which could affect results as well as keeping costs down.

Bench tests were conducted in the garden with a 5 litre container on a 50cm length of 25mm dia pipe. The outlet was hooked over a carport beam 190cm high, simply because I have no river, stream or any other similar type of environment suitable for field tests.

Step 2: Parts

Initally I used two 3/4" check valves, but after some testing I found that a 1" valve worked far better for the waste gate than the smaller one. I used a 1" connector from the valve to a 1" to 3/4" adapter to the original 3/4" connector.

Common parts

  • 1" barrel connector
  • 1" to 3/4" adapter
  • 3/4" barrel connector
  • 2 SS hose clamps
  • a 70 cm length of 20mm vinyl hose
  • straight barb fitting 20mm to 10mm
  • elbow 3/4" threaded to 20mm barb
  • 3 metres 10mm vinyl hose
  • 25mm pvc ball valve on the inlet for convenience

My custom pump body config uses:

  • 3/4" 90 deg elbow
  • 3/4" T piece solvent
  • 2 x 25mm to 20mm solvent connector

The traditional config uses:

  • 3/4" T piece, solvent on the ends and 3/4" threaded on the top
  • 1 x 25mm to 20mm solvent connector

Step 3: The Modified Check Valve

Threading the valve stem will allow varying the length of the valve stroke to fine tune it for field use.

The 1" spring check valve was opened, spring removed and valve stem threaded M6 to accommodate a M6 coupling nut for fine tune weights. I tapped the thread too far down the stem and it did occasionally bind, the top 5mm of the stem would be sufficient.

The 3/4" spring loaded brass check valve which I modified by taking out the spring and threading the brass spindle to allow for an adjustable valve to seat distance. The valve body needs to be dismantled to modify the innards, a bit of heat to the body assists in breaking the sealant on the threads, wedge the rubber seal off the seat to protect it from the hot brass. I then found the valve to be too light and discovered there weren’t any M5 coupling nuts so I tried the spring down force mod, which was very sensitive and I couldn't get consistent results.

Step 4: PVC 90 Degree Elbow Mod

This is just a standard 90 bend that has an internal 45 degree slope to transmit the pulses from the waste gate valve to the outlet check valve.

The 45 slope was created with super glue and fine glass bead sandblasting media which doesn't reflect laser beams. i.e. camera safe, but don’t take a chance with your eyes, rather wear some sort of protection if you use this method. I figured a 45 degree surface would show a centred beam in the exit part of the elbow.

Step 5: Testing and Results

I held a measuring jug under the outlet to collect the discharged water for comparison checking. I experimented with a "snifter" port to add additional water via a check valve, but it was unsuccessful so I blocked it off during testing.

During the custom config test, 5 litres was finished in 30 seconds, while the traditional config used 25 seconds for the same amount. The waste valve was fine-tuned with the M6 coupling nut to give 4mm of travel on the custom config for approx 200 pulses per minute and that setting was untouched when used on the traditional config.

The custom config pumped:

  1. 350ml
  2. 380ml
  3. 360ml
  4. 360ml
  5. 370ml
  6. 360ml
  7. 360ml

Discarding the highest and lowest readings gives an average of 362ml pumped water out of 5 litres.

The traditional config pumped:

  1. 260ml
  2. 300ml
  3. 330ml
  4. 300ml
  5. 300ml
  6. 310ml
  7. 310ml

Discarding the highest and lowest readings gives an average of 304ml pumped water out of 5 litres.

Step 6: In Conclusion

Although it seems to be a tiny difference of almost 60ml in 30seconds, that difference translates to approx 170 litres in a 24hr period, which is largely due to the more focused and directed pressure pulses.

The video shows the smoothed output due to the air resevoir in the outlet tube which cushions the hydraulic shock.

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    Question 2 years ago

    I have never seen an air reservoir set inline with the outlet hose did you come up with this yourself or did you see this somewhere else? Id love to see more information on this specific method.


    4 years ago

    Your instructions are easy to follow and your subject matter is interesting, but your instructable varied from the premise of the article: "can the pulses be better managed for increased efficiency?" Specifically, a comparison was made between a modified BreurRam to a "typical" ram when to answer the question the comparison should have been made between your modified BreurRam and a BreurRam in order to ascertain if the pulses from your modification increased efficiency of the BreurRam.


    6 years ago on Introduction

    I don't understand what I'm doing wrong. I tried to duplicate your instructable, with no luck on results. I think maybe my test setup is wrong (I use a tall abs pipe with a hose at the end for the feed in my test; the connection isn't sealed). The only thing I did differently was use galvanized steel pipe instead of abs pipe. I thought maybe I had a check valve reversed, but I seem to be using the check valves in the same direction as your diagram. Can you confirm the directions for me?

    My pump is only letting water out of the waste valve. It is not going through my hose (though it is a rather long hose). Not much water is coming out the end when the hose is off. The waste valve also doesn't "pulse" like yours.


    Reply 6 years ago on Introduction

    Initally the water will gush out of the waste valve causing the flap to slam shut.
    This sudden buildup of pressure must go somewhere and that is out the outlet pipe.
    If the water just continues to flow out the waste valve then your valve flap is too heavy.
    I had to tweak things to get just the right amount of weight using nuts on the center spindle.


    Reply 6 years ago on Introduction

    If I go back to the stock check valve (but without the spring), it still seems to be too heavy... maybe I'll try a 3/4" check valve. Thanks!


    Reply 5 years ago

    Grant Thompson shows how to make a very simple check valve eloquently.


    Reply 6 years ago on Introduction

    Or maybe I should put the spring back in?

    "I have no river, stream or any other similar type of environment suitable for field tests."

    It appears that your test emplooys a garden hose or similar 'closed system' for input.

    In the 'real world' applications, the inlet accepts a portion of whatever water may be flowing toward the inlet. Thus, the pressure at the inlet is neither assured nor constant.

    In a 'real world' application, the inlet pipe is often a long, large diameter pipe inclined toward the RAM PUMP with a screened inlet opening (debris must be kept out of the system!) that collects a portion of the brook, stream or spring water and effectively collects a significant volume of water to present to the RAM PUMP inlet.

    Thus the pressure at the RAM PUMP inlet is dependant upon the 'head' or volume of water collected in the inlet pipe - thus would not be (as) constant as the water exiting one's garden hose.

    I would suggest your test attempt to replicate the 'real world' application by using a longer, larger diameter open-ended inlet pipe at various elevations and allowing the garden hose to fill the inlet pipe without sealing a connection between the garden hose and that inlet pipe so as to acheive a more realistic test.


    7 years ago on Introduction

    Nicely done. I was going to make the original design just to try it out with all the extra bits but will make this one now. You have saved me maybe $100. I also like the idea of the waste water adding pressure to the outlet valve. I'll see how the build goes.


    7 years ago on Introduction

    Hi there,

    In attempting to copy what you have made I think I may have come up with an improvement to simplify this instructable even further. Instead of adding weight to the waste valve by tapping and threading on bolts, why not at add coupling to the end of the modified valve and extend it up to the desired length with some straight piping. This way the water which is usually wasted will function as additional weight. Different lengths of piping on the end of this valve would give you different weights. Instead all you'd have to do to modify this check valve is remove the spring.

    Just food for thought.

    Another way to improve this would to have the pipe extending the modified waste valve to be threaded up the entirety of its length, then you could thread another pipe over this pipe so you can fine tune the height of the waste valve to some extent. There is probably a better way to be able to adjust the height but that's all I can think of at the moment apart from cutting lots of different lengths for testing.