newbie needs help!!ram pump question

[alibaba]

With the use of a self contained air compartment installed in the air tank and a closed air supply in form of a pipe to the sniffer hole then can the entire unit be submerged and continue to operate? Except the sniffer pipe....

[jimovonz]

I'm not sure what you mean by 'self contained air compartment'. I have made a number of ram pumps using sealed bladders in the expansion tank. This does away with the requirement for a sniffer hole. Another option is to uses a length of flexible rubber hose on the delivery line (expands and contracts inline as the pump output pulses). You can see one of the pumps I made along with other helpful info here in this post: http://www.fieldlines.com/story/2005/6/21/152654/398. Unlike most ram pumps, I have contained the 'waste' water and directed it to a tank for other use (backup electric pump). Containing the waste water like I have reduces the efficiency of the pump somewhat by increasing outlet resistance of the clack valve. This pump has infact operated quite hapily while under water during a flood.

[cr8zy1van]

Im sure the pump can work underwater, but it will drop the efficiency. Simply because the escaping water needs to go somewhere. When it has to force its way into water, as opposed to air, it will steal some of the force that would normaly be going into pumping water. If your not looking for the greatest performance, just to get water up to a point, your plan will work just fine.

[Oso]

Placing the waste or clack valve underwater does not steal some force, it steals a lot of force. It does not allow the water to accellerate thru the ram at maximum rate, slowing the cycle time. The clack valve must also work againsst the water density, slowing its opening and closing. This reduces the pressure spikes and further impacts the cycle time.

In many cases the total reduction is so great that the ram will not operate.

My opinion is that you should never, never put the ram under water.

[jimovonz]

If the ram pump works and does something useful with a naturally available resource that would go to waste otherwise, why would you not do it? Surely as you say, there is a decrease in efficiency when operating underwater, but the ram pump is only ~50% efficient at best in any case - did you let that put you off too? "Oh, ram pumps waste 50% of the available energy, you should't bother about using them"? If it can supply a useful amount of water reliably while under water, does efficiency matter? One of my rams is effectively under about 1ft of water all the time (because I catch the waste spill). It has performed without failure for comming up two years, pumping 1500l/day up to a height of 50m using a head of 1.8m. Hardly a waste of my effort considering it consists of approx $100 worth of plumbing parts.

[TomW]

Jim;

Yeah, one mans waste is another mans water supply. It just seems to me that efficiency in a no cost of use resource is a moot point. If it is free of cost and works to do what you need who cares if it is 100% efficient or 5%. Kind of a common thing lately trying to squeeze that last couple % out of something. Seems like folks spend 90% of the effort getting 2% more.

To me its overthinking the plumbing but it keeps some of these folks busy I guess.

Its not what some folks know that worries me it's what they know that just ain't so.

Catch you on IRC soon.

Cheers.

TomW

[alibaba]

lots of helpful replies! thanks.

A. can the scenario displayed in drwaing A be achieved ?

B. having seen jim's pics i would like to know if the height of the waste tube can be extended with a longer pipe piece but with smaller diameter in that way increasing the height at which the waste water is disposed of and pipes away as shown in drwaing B. what vertical orientation does the black pipe that is shown orientated? does it go to a lower level than the pump or is there some lift?

has the water been higher than 1 foot above the pump?

[jimovonz]

alibaba, my waste pipe contains approx 1' head. The flood water has only ever been slightly over this. Although the pump continued to operate, the system was potentially contaminated (the 2500 gal tank recieving the waste water was over-topped). For the system you have illustrated, I would still go with a relatively large waste outlet pipe to minimise backpressure. Consider using a somewhat flexable pipe with the end connected to a tethered float to keep it clear of the floodwater, but still allow good efficiency otherwise. Does the flood water at the pump site sit in a basin or flow away somewhere? Having the waste contained like I have makes it not so easy to start the pump as you have to disconnect the pipe to depress the valve. Re-attaching the pipe needs to be done carefully as it is easy to disrupt the cycle - in your case may not even be possible until the flood water receeds.

[alibaba]

the waste water sits in the basin and it takes a long time to drain away, but it is pure spring water so contamination is not a problem at all ( having that in mind will there be a change in the configuration ).the basin is huge so the pump's waste water will hardly lead to an increase of the flood level in any way.

since i am in the starting stage of my pump configuration i will be more than grateful for any ideas (modifications) that might be able to solve the problem..

[Flux]

Alibaba

Having seen your diagram I suspect you will have trouble. The conventional ram doesn't like working much under water. The Decoers type can be mounted above water level and works with a suction tube much like a reaction turbine, but this will not solve your problem of reduced drive head in times of flood.

You show a dam at 4 ft and flood level at 3 ft. This only gives a 1 ft drive head and although it is not impossible to work a ram at this head, to put it mildly it will be touchy and needs lots of attention.

I think you may do better to site the ram at 2 ft level, work with 2 ft drive head and accept that it is going to stop in times of severe flood.

Flux

[alibaba]

thanks. ok, one last idea i wish to share before i totally quit the entire ram pump thing:))

check the image

what will the effect be if i was to isolate the pump in a concrete or other tuogh material so to make sure there is no water around it and to maintain my 4ft of head which must be available in order to achieve the 15ft lift. the only problem remains the waste water as you can see i nees it out of the isolator tank, and that would either mean a higher lift for the waste water or a a pipe or something..but i think  backpressure might be a serious problem...any ideas

by the way any links to a Decoer type suction pump? google could not help much.

[jimovonz]

This setup does not improve your situation. The amount of energy available to use is proportional to the difference between the drive pipe inlet and waste outlet head. After telling you that the ram will potentially work underwater, I think in your situation the flood level is such a significant proportion of the drive height that there is little chance of it working. In my situation 1' of flooding represents ~1/10 of the drive height. In your situation your looking at up to 3/4. As Flux has pointed out, you are already working with a minimal drive head.

[alibaba]

allright, i guess that wont work in anyway.

i have found a new site with much higher head - 12ft. the floodeing problem still stands though.  

how about this setup- will the backpressure on the waste pipe be too big and make it inefficient?the waste pipe will have 3ft fall by the time it re-enters the dam.

[jimovonz]

I'm not sure if I understand your new set up. Are you proposing to take water and then return it to the same? i.e. the inlet pipe and waste pipe are at the same head of pressure (and consequently will not flow...)?

[Flux]

I don't follow it either, he seems to have no idea of the concept of head.

The only hope on that site is to find a point where the supply head is at least 2 ft above the flood level, mount the ram there and work with that. From another post that vanished I find that there is plenty of flow. There should be no problem supplying a lift of 15 ft from a 2 ft drive head but it may need a slightly unorthodox beat valve with spring bias. I would even attempt it with 1ft 6" drive head but you wouldn't do it with a commercial ram with standard valves.

Any attempt to consider trying to use heads below the flood level are doomed to failure. It may be possible to use a larger head and accept that it will stop during certain periods.

If there is significant flow in the flood water it may be possible to have a spiral pump to take over at times when the ram is flooded but there is far too little real information to decide what is going on.

Flux