Ram Pump Help

[Kevin Mckee]

ok, I've been researching ram pumps on and off for a couple of years now,(more off than on) and am thinking about them again. here is my problem most designs I have found are for higher flow, low drop situations, 1 gpm min.  here is what I have to work with. the cabin is on a hillside.

1/2 gpm year round from a spring at cabin level.  25 foot drop to bottom of the hill.

tank at the top of the hill, 40 feet above the cabin, or 65 feet above the bottom of the hill.  is this workable with a ram pump?  i know it won't deliver much water, but I

don't need much, and am away a lot, giving the tank time to fill.

ps, current system is a shurflo that will serve as a backup for the new system.

[stephent]

http://www.i4at.org/lib2/hydrpump.htm

seems do-able to me.

[Nando]

Your problem is the Ram Pump losses, which for you, is about 8 to 12.

So for each gallon in the upper tank you will need about 8 to 12 gallon from the spring.

I think that you have the best arrangement right now, of course, you have a good electric pump and if you have two tanks, one at the spring and the upper tank with a level detector in the lower tank to turn the pump when full, if the upper tank needs filling.

Also, how to solve the low water volume available for proper ram pump, which in this case You can put a tank at the spring to fill, like a 55 gallon tank, then you use a siphon to start the water going down to the ram pump to operate until the tank is empty when the siphon does not work anymore.

The ram needs to be small and well made.

A preferable system would be a dual bi-directional pump set up, which operates without the need of a tank or siphon and may pump once a minute when enough water is in the pump pipe.

Nando

[Kevin Mckee]

Im not to concerned with the ram pump losses.  1/2 gpm = 30 gph, if my losses are 12 to one that is still over 2 gph 24/7, i dont go through 50 gp day, more like 20 - 30, and i have a 250 gallon tank up in the shop.  the spring has a 50 gallon tank. ive thought about emptying the tank at a higher rate, instead of letting it overflow down the drive pipe, but that means starting and stoping the ram a lot.  most of the plans i've seen describe a startup process requiring some one holding open the clack valve.  

what is this bi-directional pump?

[Flux]

You are at the very bottom limit for a ram pump. I suspect it will work, I have got them to work at that flow with lower heads and the higher head may be in your favour.

The 3:1 ratio of heads should be to your advantage, perhaps you may have to artificially increase the delivery head a little.

I have never been able to get small commercial rams to work down to this flow level with rubber disc valves but decent metal seat beat valves seem to do better. For the low head I had to spring bias the valve open, you may have to do the same.

Don't try too large a drive pipe, I used 1" at 3ft head, you will likely need smaller, I think I would try 3/4" first.

If all else fails you can run it intermittently as Nando suggested, I have never tried it but it has been done.

Flux

[Nando]

Kevin:

A bi-directional pump is the equivalent to a ram pump.

The unit does not behave like a ram pump, as a principle, it has two pistons, with an area ratio high enough to raise the water to the upper tank.

25 feet drop and 65 feet raising, the ratio is 65/25 = 2.6 and to correct for frictions this ratio is increased like 4 to 1, but due to how the water is fed to the pushing tank the volume becomes 5 to 1, one (1) for pushing and four (4) for pressure that goes down hill to the ground, if the system is using the same flow for pressure and pushing.

So the pressure piston, which is filed by the spring, is 4 times larger area than the raisin piston to bring the water to the tank.

The pressure pipe fills and when with enough head, the water in the second pushing piston feeds the pipe going to the upper tank, in this case the water volume delivered would be 1/4 of the water available.

Bi-directional pumping for easier mechanical set up, which is done by the piston's position to change the water direction feed in the pressure piston, the pushing piston has 4 one way valves to allow flow in/out automatically.

The critical part is the directional water valve feeding the two sides of the pressure pipe in sequence for proper directional pressure cycling.

Nando

[Kevin Mckee]

are plans for bi-directional pumps floating around on line any where? or would it have to be a commercial unit. i googled it without success.  i can sort of visualize how one would work, but not well enough to build one.  the ram caught my attention because its something i can build my self, but i do have access to a foundry and machine shop for something a little more complex.

[Julio]

Try de Develpment of Technology Unit (College of Engineering)of Warwick University. They have plans, calculations and other things that may suit you.

Julio.