Bert> By the way, specifically what were you using
Bert> one of these device for? [Thromp Pump]

For many years I lived in a deep valley with a large creek flowing in my front yard. I was trying to run a generator. There was lots of volume of water but no head, so I was fiddling with getting the water higher, since I could pump it for "Free" using the thromp. Never really did work out, the Thromp got washed a way to many times when the creek flooded.

Noisy beasts. Now I remember what was missing from that drawing. There is a air cylinder, that I made out of 3" schedule-80 pipe about 3 feet long. This creates the water hammer effect. Also some times the air cylinder gets water logged. If you have this problem, a way around this is to put a very small hole at the bottom, with a bobbie pin in it. The pin vibrates and keeps the hole from pluging up with sand and such. Make sure your input is well filter, but not so well filtered that it reduces the velocity of the water much.

Heres a corrected drawing: [need to work on this]

Because this is not 3-D it is not exactly right. The cylinder stands vertically, while ever thing else is layed out on some horizontal fixed object, like a cement pad.

It works like this: The input water forces the clack valve closed. This cause pressure to build in the air chamber. At some point the air will reach a point that it won't compress any more, and "kick back" [Or explode on your first few attempts. :-< ]. This "kick back" provides the energy to open the check valve, and push the water up the output pipe to where you want it. As the "kick back" dissipates a small vacuum is created that cause the clack valve to open, then the cycle repeats, until you A) Run out of water, B) Break a spring, C) Suck in a frog [yuck] ect.

You can make these any size you want depending on your available input flow, and how much you want to get out of it. For example 1" in 1/2" out. I just used the parts that where available to me.

It took a while to figure out how to make a Clack Valve. I discovered that the check valves that I had could be taken apart, and put together backwards (move the spring). Make sure you have extra springs on hand as they are the week link.

I learned to have lots of respect for compressed air and flowing water from these experiments. Almost had my head caved in by a pipe that broke lose when I opened a valve to release "just a little bit of trapped air in the line". It started flopping around like a angry serpent, it took off my hat, it was so close to my head. Also almost lost all of the fingers of my right hand when I accidentally created a vacuum trying to cap the input end of a flowing pipe to stop the water from going in.

"Its only water" and "Its only air" just don't have the same meaning as before....