When there's no flow, water is allowed to freely run out the waste valve, as the flow increases at some point it pushes the waste valve closed which slams shut very quickly. All the water in the feed pipe has to stop, and that makes the pressure spike, pushing a little bit of water past a check valve on the high pressure side. Then when the water has stopped flowing, a weight on the waste valve pushes it open again until the water is moving fast enough to slam it closed, repeating the cycle.
The down side is that you only can possibly pump as high as the fraction you waste with perfect efficiency. So 2 meters of head pressure pumping up a 10 meter hill, with 50 percent real world efficiency means dumping 10 gallons for ever gallon pumped.
Well, ironically you'd need a powered pump to get it back into the system. Essentially, you're using energy from some of the water flow to do the work to pump the other water.
Practical Engineering has a video about it
I can't get enough of these videos.
Ha I was going to say "no way send it to Grady at practical engineering!" But I guess the man's ahead of the game as usual
Farmcraft101 on YouTube did a fantastic job explaining this style of pump.
Glad there are a few videos explaining it, I can't wrap my head around it!
When there's no flow, water is allowed to freely run out the waste valve, as the flow increases at some point it pushes the waste valve closed which slams shut very quickly. All the water in the feed pipe has to stop, and that makes the pressure spike, pushing a little bit of water past a check valve on the high pressure side. Then when the water has stopped flowing, a weight on the waste valve pushes it open again until the water is moving fast enough to slam it closed, repeating the cycle.
The down side is that you only can possibly pump as high as the fraction you waste with perfect efficiency. So 2 meters of head pressure pumping up a 10 meter hill, with 50 percent real world efficiency means dumping 10 gallons for ever gallon pumped.
Inefficient for sure, but a great choice if pump speed isn't an issue, and water source is something effectively limitless like a river.
Cool. But last line ruined the entire video.
Remember, I love you.
Could have some sort of bunding/grate to collect the unused water and put it back into the system? Very cool though!
Well, ironically you'd need a powered pump to get it back into the system. Essentially, you're using energy from some of the water flow to do the work to pump the other water.
He said "ram" pump, right? It's a ram pump..
I'm not clever enough to know how that works
Easy to understand graphic here: Hydraulic ram - Wikipedia
It uses moving water (with the water hammer effect) converted into air pressure to operate two check valves.
One has been running in Estonia since 1938 only stopped for replacement of seals from time to time
“There is nothing powering this, except water pressure”
So true