Using low pressure water flow to generate low flow enhanced pressure.
Using low pressure water flow to generate low flow enhanced pressure.
(OP)
I have a project where a water supply of less than 0.1 bar and flow rate 5-10 L/min. I would like to use this water flow to produce a 2 bar stream of water at 0.2 L/min. Effectively intensify pressure using the kinetic energy of the flowing water. I have seen systems like hydraulic ram pumps that use river flow to pump small amount of water well above level or river.
http://en.wikipedia.org/wiki/Hydraulic_ram_pump
However these are large and pulse at low frequency (0.5 or less Hz).
Anybody come across a miniature version that pulses at 10 Hz or higher to produce a smoother flow?
I have the system working with a miniature electric pump the performs well but I would like to eliminate the need for external power source.
Application is domestic water.
Thanks
http://en.wikipedia.org/wiki/Hydraulic_ram_pump
However these are large and pulse at low frequency (0.5 or less Hz).
Anybody come across a miniature version that pulses at 10 Hz or higher to produce a smoother flow?
I have the system working with a miniature electric pump the performs well but I would like to eliminate the need for external power source.
Application is domestic water.
Thanks





RE: Using low pressure water flow to generate low flow enhanced pressure.
RE: Using low pressure water flow to generate low flow enhanced pressure.
GPM x 8.33 lbs/gallon x specific gravity = lbs/minute of fluid
x head (ft) = ft-lbs/min
33,000 ft-lbs/min = 1 hp
Sorry for the units, but check your available conditions vs what you want to generate. Make sure you factor in efficiency allowance your device(s.) If you have enough margin on efficiency, you might even be able to use a turbine as a generator for low pressure side, then connect to a motor for the high pressure pump. Battery as a buffer, add solar panel for additional energy?
Maybe some sort of direct drive device if you are cutting it close on efficiency.
RE: Using low pressure water flow to generate low flow enhanced pressure.
RE: Using low pressure water flow to generate low flow enhanced pressure.
http://www.minibooster.com/products/boosters-oil/h...
They are not cheap.
Ted
RE: Using low pressure water flow to generate low flow enhanced pressure.
What velocity does the main stream have or can it be made to achieve?
RE: Using low pressure water flow to generate low flow enhanced pressure.
http://www.haskel.com/corp/details/0,,CLI1_DIV139_...
RE: Using low pressure water flow to generate low flow enhanced pressure.
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Using low pressure water flow to generate low flow enhanced pressure.
The eductors like Dave suggests might also work, but that assumes you have a high flow velocity - not sure that's true here, it's the one piece of information asimpson hasn't given us. If the velocity is high enough for an eductor to generate the required pressure, then even a simple pitot tube would provide the required flow...
RE: Using low pressure water flow to generate low flow enhanced pressure.
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Using low pressure water flow to generate low flow enhanced pressure.
I am not sure how diffuser would work.
I'm afraid I don't want to use any other power source other than the motive power of the water.
The velocity through 1/2" pipe would be 129 f/min or 39 m/min. Given the low pressure supply. In this case about 2 m head of 6 ft. for the supply pressure. Using a nozzle to increase velocity may be ineffective and just result in lower flow rate.
I don't see how an eductor could produce a pressure greater than the supply pressure. I understand how they can pump large volumes of liquid using a small flow supply that has high velocity by jetting it through nozzle under pressure.
Mechanical pressure intensifiers seem to be on a much larger power scale than in my situation and friction losses would probably overcome the whole system. That is why the ram pump seemed like a possible solution. It has virtually no moving parts . But I have seen no examples on the scale I require.
RE: Using low pressure water flow to generate low flow enhanced pressure.
Respectfully, I'm guessing that your schooling was not in ME, or it all would have clicked when you heard "Bernoulli".
For a given stream of constant mass flow, velocity and pressure can be manipulated by changing cross-sectional area.
http://www.learnthermo.com/T1-tutorial/ch05/lesson-C/pg07.php
RE: Using low pressure water flow to generate low flow enhanced pressure.
"I don't want to use any other power source other than the motive power of the water" ... i don't know this equipment but i'd've thought you were doing work on the fluid to increase its pressure (so i think you need external power.
RE: Using low pressure water flow to generate low flow enhanced pressure.
http://www.riferam.com/rams/ramspecs.html
It looks like you'd need a Davey #2
RE: Using low pressure water flow to generate low flow enhanced pressure.
This sounds like a water wheel driving a centrifugal pump kind of application.
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Using low pressure water flow to generate low flow enhanced pressure.
Could this be used to pump a small portion of water say 10% to a tank higher than the header tank feeding the main flow? Just like a hydraulic ram pump.
RE: Using low pressure water flow to generate low flow enhanced pressure.
RE: Using low pressure water flow to generate low flow enhanced pressure.
One of two things must happen:
1.) outside energy input
2.) energy transfered from one portion of the flow to another (e.g. turbine pump).
I thought there might be a way to do this without a pump, but I'm not geting there.
RE: Using low pressure water flow to generate low flow enhanced pressure.
rmw
RE: Using low pressure water flow to generate low flow enhanced pressure.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Using low pressure water flow to generate low flow enhanced pressure.
RE: Using low pressure water flow to generate low flow enhanced pressure.
All the ramp pumps on the market seem a bit "agricultural", no offense intended. I need something a bit smaller. Guess I'll have to do some work and try to build one to my specification. Should be interesting.
RE: Using low pressure water flow to generate low flow enhanced pressure.
RE: Using low pressure water flow to generate low flow enhanced pressure.
Ted
RE: Using low pressure water flow to generate low flow enhanced pressure.
and Dave, I hate to nitpick especially somebody like you who is pretty sharp all around, but this statement is incomplete:
"You can get the velocity you want/need by picking the right pipe. "
- I would add: "but only if you have the source pressure (head) to drive that velocity", which was why I kept bugging asimpson to spec his source pressure. I know you stated you missed the low source pressure in a later post, but that comment just bugged me, seemed like you were saying "duh" to my earlier post.
RE: Using low pressure water flow to generate low flow enhanced pressure.
I misread data on Davy #2 and I will look back at it. However so far it is the only system available close to what I require
RE: Using low pressure water flow to generate low flow enhanced pressure.
I think most feasible is turbine (or waterwheel) driven generator used to charge a battery, which drives an electric motor centrifugal pump.
Low end of supply flow and not enough power? Add another turbine/waterwheel to the system, or other "free" power source (solar.) Or if it is a temporary reduction in flow, just ride it out on battery power.
Don't know how consistent you need the high pressure flow to be, but I think you will have to go electrical here.
RE: Using low pressure water flow to generate low flow enhanced pressure.
(*) A standard hydraulic cylinder with a big honkin' weight on the piston rod.
RE: Using low pressure water flow to generate low flow enhanced pressure.
Sparkies don't believe in conservation of energy. Strange religion, EE is.
RE: Using low pressure water flow to generate low flow enhanced pressure.
more sites regarding ram pumps:
http://journeytoforever.org/at_waterpump.html - lots of how-to type info.
This one says they have a pump that operates on as little as 2 ft. of fall, might be worth a closer look:
http://www.gravi-chek.com/html/about.html
RE: Using low pressure water flow to generate low flow enhanced pressure.
Pretty sure ways to convert rotary to linear motion are well understood so why not a simple reciprocating positive displacement pump or some such.
Again an accumulator or simple header tank system or similar could be incorporated as required to smooth flow.
Or if you want to stick to rotary motion maybe an archemdies screw or some such but then you'd probably be looking at gearing again.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Using low pressure water flow to generate low flow enhanced pressure.
Friction is almost non-existent with diaphragm sealed pistons.
Combine the principle of an air operated double diaphragm pump (AODD using water pressure rather than air pressure) with pressure booster. Another way to look at it is that a hydraulic piston motor with a large piston area drives a hydraulic piston pump with a smaller piston, and it is double acting so pumping occurs while stroking both ways.
RE: Using low pressure water flow to generate low flow enhanced pressure.
Not talking about "magic", overunity, or perpetual motion. As I mentioned earlier, acquiring energy from part of the stream to deliver smaller part to a higher altidude.
RE: Using low pressure water flow to generate low flow enhanced pressure.
RE: Using low pressure water flow to generate low flow enhanced pressure.
Maybe, using magneto-fluid-dynamic pumps/turbines? But I coubt there is enough efficiency in current MFD tech to make this particular application work.
RE: Using low pressure water flow to generate low flow enhanced pressure.
As a black box you seem to be wanting to convert a large supply of hugh entropy fluid into a small supply of low entropy fluid and the remainder at even higher entropy.
At first sight this is perilously close to a Maxwell's Demon situation, but given that a hydraulic ram, or a generator/pump, actually achieves this, obviously 2LE is not broken. The reason is that you do have reservoirs at different entropies, whereas the demon is more concerned with creating reservoirs from a uniform mush.
Perhaps one way you could do it with no moving parts is with a series of hydraulic jumps and overflows, to build gravitational PE.
Cheers
Greg Locock
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