Pump Engineering Novice... Looking For Help

[EnquiringMind]

Hi there,

My name is Michael, and I am looking to have a fluid pump engineered for a specific application.

I really don't know where to begin, as I am not familiar with this field, at all.

What I am looking for is someone to look over a concept I have for a fluid pump.... look at all the numbers... and tell me if my design is feasible or not.

I would like to have my concept created on computer, with numbers crunched, to prove the pump will work as I want.

My question is... who do I seek out to help me do this? And how much would something like this (in general) cost me?

I was hoping to find someone in Connecticut that I could work with, but I'm not sure where to look.

I would appreciate any help you folks could provide.

Thanks!

 

[BigInch]

Can you give any more details about the specific application?

I'd suggest you contact a mechanical engineer in your area and ask for his help, or if he knows of anybody nearby with pump design knowledge. He should review and evaluate your concept before you attempt fabrication of a prototype.

Cost estimates are impossible w/o knowing anything about the type of pump and the intended service and the specific application. Its best to have somebody look at what you have done so far to see how much more work remains and to tell you what that might include.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[offonoff]

If you could describe the mechanism we could probably point you in a more specific direction. Is it a pump based on changing the volume of a space, like a piston or a scroll compressor? or is it a fluid dynamic thing like a turbine or a molecular pump?

there's different people you would talk to depending on the filed of physics involved in studying its behavior.

also, your pump may already exist. its a big world.

 

[EnquiringMind]

Let me back up a second here, because my original post makes it sound like I'm trying to create a new pump.

I am not. What I want already exists. I just can't seem to find it anywhere.

Here is an example of what I want.

http://www.fluid-flow-control.com/plunger-piston/plunger-piston.html

See the pump in motion on the right? That's all I want... except the wheel would be on the bottom... so that the piston is being driven up and down... with those same inlet and outlet check valves.

I see pictures like that when someone is describing a force/piston pump... yet when I go to these manufacturer websites, all the pumps look so foreign compared to what I want. They look like huge cast iron tanks with all kind of knobs and tubes and other stuff... instead of the simple pump in the link above.

I have contacted a few manufacturers, and they are of little help. I guess I will try some more, but if anyone in here can help me find what I want, even better.

Now that you know the type of pump I want, the key for me is to know how much water it can pump with one single stroke of the piston.

I am not using the pump in a high RPM way... just a couple strokes per minute.

The holy grail for me would be to find out this type of pump I want can be made out of PVC Pipe/Plastic and other cheap materials.

Sorry for the rant.

I just want to be able to find the type of pump I showed above. I can work out the details with a manufacturer afterwards.

 

[offonoff]

We'd need more information still to direct you. For instance, fluid refers to both gas and liquid, and there are different requirements for each in a pump (sealing purposes).

You can determine the volume per stroke of a pump with its RPM and gallon per minute figures (if you were buying an off the shelf pump). Or, if you know the cross sectional area of the bore and the stroke length (if you were building it).

A pump can be built from pvc, depends on the pressures and forces involved. The cylinder should have a bursting pressure well above the maximum pressure. The shaft must be more than capable of not bending under a force of the maximum pressure times the cross sectional area of the piston (so a pvc shaft probably wont work).

here:

http://www.virtualplacebo.com/halloween/props/pneumatic_piston.htm

not a pump, but its the basic piston design that could be run backwards as a pump. check valves could take care of your valving with no electronic control.

Depending on your requirements, a simple hand water pump or a piston type compressor from a car's AC (call a wrecking yard and you can get one for 10 bucks) are both available items that could be run from a prime mover of your choice (electric motor, bicycle, etc.)

basic physics will be enough to model your pump, you don't need finite element analysis (or a computer).

 

[EnquiringMind]

Just assume I am pumping water. Fluid was probably the wrong term. I should have said Liquid. Sorry.

I see what you are saying. I have seen those type of homemade pumps while doing research.

Ideally, I want something that is "fatter" and shorter instead of long and thin (like the one in your picture).

Why? Because I am concerned about the intake being that high up. I would have to run a tube/pipe from the intake down at least a couple feet into a pool of liquid. I assume the downstroke of the piston would open the check valve and draw water up the tube/pipe and into the chamber.... but wouldn't there be some problems associated with this?

I have assumed all along that I want the intake to be lower that that... because I intend it to be submerged in liquid. Try to imagine the intake part going into the side wall of a swimming pool.

Wouldn't that be better than having a tall pump (with a high intake point) that has a hose/pipe running down into the middle of the swimming pool?

I don't know the answer to that... perhaps you might?


Just for reference... I am looking to pump between half a gallon to a gallon of liquid with each piston stroke.

 

[EnquiringMind]

P.S. Thank you for your help thusfar. I appreciate it.

 

[Apakrat]

Dependent upon the elevation above mean sea level, and a few other factors, most every piston pump will lift a liquid such as water several feet.

The pump linked byoffonoff, will probably work just as well laying flat, with the inlet elbow looking down, with a nipple extending into Your water surface.

Therefore, the piston pump does not have to be submerged!

You could put a pipe into the wall of the swimming pool where You want it, run pipe to a pump somewhere higher, suitably fitting Your working area aesthetics.

Most pump manufacturers will provide "lift capability" for their pumps.


At 74th year working on IR-One2 PhD from UHK - - -

 

[EnquiringMind]

Apakrat,

I do not want the whole pump submerged. I just want the intake to be well below the "water line".

Why?

Because I don't have anywhere near the same downforce on the piston as I do upforce on the piston. (I'm not gonna bother trying to explain why).

The less work required to draw the water into the chamber, the better. That is why I would prefer a shorter, fatter pump with an intake below "sea level" than a taller, thinner pump with an intake above sea level that needs to draw up water (which requires work on the downforce of the piston).

Does that make sense?

 

[hydtools]

Here are piston pumps by Dayton:

http://www.drillspot.com/products/73538/Dayton_3YB50_Twin_Piston_Pump

Ted

 

[offonoff]

The force needed to suck water into the chamber above "sea level" (water level) is the psi vacuum needed times the cross sectional area of the piston. IE: to lift water 10 feet, 5 psi vaccum is needed (1 atm=15psi=30 ft water), with a 2 square inch piston thats 10 pounds, plus some pounds for friction. A bigger piston requires more force, but over a shorter distance for same volume, just like a gear ratio.

hydtools pump is a simple pump as you've described, with no extra nozzles or ports. Is there a reason you need to engineer something from scratch? if you know your head and flow requirements and can describe the capabilities of your power source (sounds like its kids on a see saw or something unusual), then a previously manufactured pump can likely be found.

also, check valves work on pressure differential. the piston moving one way will cause one valve to close and the other to open, moving the piston the other way causes them to switch again. i dont think there are any problems associated with that.

 

[EnquiringMind]

Let's go back to this... because this is perhaps the most important factor.

I need to pump 1 gallon of liquid with every stroke of the piston.

Anything more would be great. Anything less than that I can compromise a little (say down to 1/2 gallon per stroke).

I'm sure there are pumps that can do this... do you know where to find them?

All these piston pumps are "max 3gpm at max 4800rpm" for example. I'm a pump novice, but that sounds like a very small amount of liquid being pumped per piston stroke.

Those pumps seem to be designed to do the work I want with lots of piston strokes (rpm). I am trying to do the same amount of work with minimal piston strokes (like 2 strokes per minute).

I cannot even consider a pump that will do less than 1/4 gallon per piston stroke.

I would bet that would narrow down the field considerably... but hopefully I am wrong.

That is probably the criteria to start with... because it will (I assume) immediately remove a large % of the pumps on the market.

 

[EnquiringMind]

I think I could work with a diaphragm pump. They seem to be much higher capacity, and I think I could adapt it to my power source.

 

[offonoff]

If you need the low rpm because of the output you want (gushes of liquid every 30 sec), then a simple toilet like accumulator could do that from a common pump.

few power sources give any decent power with any reasonable efficiency at low rpm. also, smaller cylinders being filled and emptied quicker makes for a smaller pump. I dont know of any existing market that uses extremely low rpms, nor single 2000 gpm pumps (that at 2 rpm would give just a gallon per minute). maybe there is an industry, but i dont know of it.

gearing your power source to suit a higher rpm pump is the usual solution.

are you sure your power source can move such a large volume without being geared?

A hydraulic machinist could put a piston in nearly any diameter cylinder you want, and seal it well. but a machinist would need drawings and specs, someone to engineer the thing. hopefully someone here knows where those engineers (and the pumps they've designed) are.

good luck

 

[EnquiringMind]

offonoff,

Check out this diaphragm pump. 1 gallon per stroke.

http://www.edsonintl.com/pumpstore/index.php?main_page=index&cPath=86

I just wish it were about 1/20th the price. It appears these pumps are about $700 or so a pop.


Yeah... I need to get alot of work done each time my power source fires. There are some odd limitations that can't be worked around.

The issue is finding the pump to match, given that my power source can only fire vertically (which is why I initially focused piston pumps, and now diaphragm pumps).

I still haven't found a pump that can use a vertical power source, pump out what I need, and not cost a fortune.

I'd like to think there is something out there that can fit my limitations and still satisfy all my criteria... but I'm not finding it. Too bad that pump linked above is so expensive.

 

[b30715sq]

I hope you have find the right books for you.I am a greenhand in this area and hope to mutual prompt with you all.

 

[hydtools]

Make your own like this homemade bilge pump.

http://www.geocities.com/shawnkayak/pvcpump/

Ted