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Hello,

There are quite a few people who are interested in building ram pumps for different reasons so I am writing up this follow up post with my design and rationale and a few links that I found useful.

To start, I want to raise water about 16' from a creek that flows throughout the summer to a 275 gallon tank that I can use for irrigation purposes. The creek does not have much fall to it so I had to do a small amount of damning with some field stone, though far less than my local beaver friend. I have been looking at building ram pumps for probably two years and have spent probably 40 hours or more online looking at different models/designs and watching Youtube videos. There is a lot of good information out there.

Here is a quick summary of the basic concept of a ram pump. Water flows down a drive line and out the waste water valve. After enough pressure builds up the waste water valve slams shut and the sudden block creates a "water ram" which is a shockwave of pressure that runs back into the drive line. The air filled pressure tank compresses much easier than the water filled drive line and so water is forced past the check valve and into the delivery line. After the pressure is released, the waster water valve fall back open and the process repeats itself. (See attached pictures)

There are two basic configurations that differ by where the waste water valve (or impeller valve) is located. One configuration places the waste water valve on an elbow at the very end of the drive line right after a T that goes to the pressure tank. The option is to locate the waste water valve on a T before the check valve that leads to the pressure tank. I spent many hours trying to figure out which was the most efficient system and finally came across one research paper that said that at least at a small scale it doesn't make much difference. I decided to go with the waste water valve at the end of the system because the concept behind the water ram is to create the largest possible shockwave when the waste water valve closes. With the waste water valve at end of the system there is no back flow from the water hitting the check valve to slow down the water coming in from the drive line. 

The sizing of my ram pump with a 1" intake/drive line comes mostly from cost and because I don't need to move that much water. The largest cost for the pump were the 1 1/4 inch foot valve and the 1 inch check valve. I used a slightly large foot valve than the rest of the system because in my research I had heard that by allowing more water to move quickly out of the system through an enlarged waste water valve it is possible to create a larger shockwave when the valve closes. I also chose foot valves and check valves instead of swing valves because it is possible to alter how quickly they close by adding spacers or weights to them. I also chose a foot valve instead of a check valve for the waste water valve because they are inexplicably cheaper.  I chose brass instead of plastic for longevity and system control. I used a 1" PVC drive line instead of plastic irrigation pipe because the rigidity of the PVC is suppose to help push the shockwave of the water ram into the pressure tank instead of the drive line just expanding under pressure. It also keeps air pockets out of the drive line which can make the system not function as well. I have seen videos of many systems that use black plastic irrigation line to run much longer distances and they work quite well so it really just depends on the system begin designed. If you use irrigation line you just have to be sure there are no air pockets in the line.

I built my own pressure tank using a 2 inch PVC tube that I already had on hand and fitted it with a 2 inch cleanout on top. I was concerned that the cleanout would not hold air, which it did not, but it does allow me to access the pressure tank without taking it off the pump. The pump actually did run even though the cleanout bled all the air out of the pressure tank, it just did not move very much water. So I put an inflatable ball in the 2 inch pipe and now the system is working much better. I think that I can get to be even more efficiency with a different kind of air bladder in the pressure tank. I think the ball is too small and has too much pressure. I need something that fills the 2 inch pipe with more air and creates a better pressure balance. The idea is that the air is there to be easily compressed by the shockwave created by the water ram. So too much air pressure is actually detrimental to the efficiency of the system.

The check valve and the foot valve both had to be modified by taking the spring off the valves, which hold them closed. I didn't initially take the spring off the check valve that went to the pressure tank but even the slight amount of added pressure by the spring greatly decreased the water going to the delivery line because my system is so small. I also had to add an overly large nut, essentially as a thick washer, on the foot valve to decrease how far  it can "open" because there wasn't enough pressure coming from the water in the delivery line to close the system without it. If I had two washers it would work better because right now the ramming action happens a little too quickly and I think I am losing some potential shockwave power.

I bought the check valve and foot valve at Tractor Supply and the rest of the parts at Paris Farmer Union. My local Tractor Supply did not have all the irrigations connectors which is why I used different stores. All told I spend about $100 on the pump not including the 275 gallon tank which I bought off craigslist for $75 (what a find!) and the 3/4 inch irrigation line that runs to the tank. It is possible to make the same size system for significantly less by using PVC pieces that are glued together instead of screwed together and by buying valves through other sources. I just saw that Brookdale Farm in NH has very good prices on valves! I chose to screw it all together incase I want to alter the design at all. It is possible to find everything you need at your local hardware store though it may be slightly more expensive. I did also look at buying everything online but it was actually incredibly difficult to find all of the connectors I needed this way.

Here is a link to a Youtube video by Bohumir Stehlik where he describes how to build a similar sized ram pump: 1'' RAM PUMP - almost 5000L per day - DO IT YOURSELF, step by step - YouTube

I found his videos to be extremely informative and easy to understand. He also has one that compares check valves, foot valves (he calls them something else), and his homemade valve for waste water. The homemade one works the best though I think the foot valve we can buy here is practically the same design as his homemade one so that is what I ended up going with. I think his videos on ram pumps are some of the best ones I found. He also is a classical pianist so if you enjoy piano music, he is also worth watching.

The NRCS also has a lot of information on ram pumps. Here is just one link:
Hydraulic Ram Pumps (usda.gov)

And finally, I am attaching a few pictures that show the system that I built.

I hope this information is useful for people who are interested in ram pumps. I have built all of one but I did a lot of research on them and am happy to answer more questions if people have them. Probably my best advice if you are thinking about building one is just buy the parts you think you need and build it. They are a surprisingly simple and power free way to raise water.

Thanks,

Nathan Hammer
Firefly Fields
802-522-4261