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RTPBurnsville
07-10-2009, 11:30 PM
Just wondering if anyone knows where one could find a drawing to build a small peristaltic pump. I would like to pump between 0.05 to 1.0 ml/minute. It looks to be fairly straight forward project using a eccentric with a roller such as a small bearing. I have a variety of step and dc motors to drive the pump at variable speed rates.
Thanks,

Rustybolt
07-10-2009, 11:49 PM
The ones we use have two bearings on a cross bar that is run by a DC motor through a gear reduction, the eccentric is in the cast housing that the bearing run in. The hose is just vinyl tubing. My boss pays 1200.00 dollars for ours and they look dead simple to build. As a matter of fact you can buy all the components from McMaster Carr and build one for about 600.00 dollars.

barts
07-11-2009, 12:18 AM
http://en.wikipedia.org/wiki/File:Eccentric_pump.gif

That one looks really simple and cheap to make....

- Bart

andy_b
07-11-2009, 12:37 AM
if this isn't in some NASA-certified cleanroom or some medical situation, just use one of these:

http://www.omega.com/ppt/pptsc.asp?ref=FPU100&Nav=grel07

i think i have the FP106 to dose chemicals into a saltwater fishtank i have. i am not using it right now, but at one point it ran for about 3 years and all i did was replace the tubing a couple of times and oil the bushing in it. $78 is a HECK of a lot cheaper than $1200.

andy b.

darryl
07-11-2009, 02:49 AM
For that low of a volume you could salvage the ink pump from a scrap printer. The last one I salvaged was a complete unit by itself, so it would be easy enough to mount and hook up.

ptjw7uk
07-11-2009, 04:42 AM
I thought all perstaltic pumps used silicone tubing as vinyl would tend to loose its plastisiser to whatever it was pumping.

Peter

Evan
07-11-2009, 08:09 AM
Vinyl isn't suitable for a pump as it is too stiff. Silicone tubing is the material of choice.

You should be able to figure out how to build one from these pictures.

http://ixian.ca/pics6/ppump1.jpg

http://ixian.ca/pics6/ppump2.jpg

Weston Bye
07-11-2009, 08:11 AM
I once had a requirement for a drip-feed of lubricant during a durability test of a product. The test had to run continuously for a couple of weeks. None of the off-the-shelf peristalic pumps would have survived or had the fluid compatibility (ATF). Any other pump I could find provided just too much volume.

I ended up building my own piston pump. The pump was similar to a wobbler steam engine, the piston and cylinder with check valves submerged near the bottom of the fluid reservoir, a long connecting rod to a 40-50 rpm gearmotor driven crank. No rings or seals were fitted to the piston, just a close fit to the cylinder. The pump only had to lift the oil 3-4' and no pressure was involved. Bore was 1/4" stroke was 3/8". Oil from the test was collected in a sump and drained back to the reservoir.

I can post photo & drawing next week if any intrest.

Rustybolt
07-11-2009, 09:56 AM
I thought all perstaltic pumps used silicone tubing as vinyl would tend to loose its plastisiser to whatever it was pumping.

Peter


We use them to pump special Locktite products and Scotchgrip(registered trademark). One is water based and the other petroleum solvent based, acetone, I think. The secret ingredient in both is diotomacious earth. The tubing is usually replaced after a couple of runs, depending on the volume. Silicone rubber just won't stand up. It all depends on what you're pumping.

spkrman15
07-11-2009, 10:05 AM
Hey Wes,

I am curious about your design.

Rob :)

Circlip
07-11-2009, 01:10 PM
Have a look at the mechanical lubricator for a model steam loco Rob, basically an inverted "Wobbler", the "Flywheel" has ratchet teeth cut onto it and is turned by a rocking lever.

Regards Ian.

Weston Bye
07-11-2009, 04:31 PM
Hey Wes,

I am curious about your design.

Rob :)
Photo and drawing(I hope) Monday or Tuesday.

MikeHenry
07-11-2009, 05:54 PM
Vinyl isn't suitable for a pump as it is too stiff. Silicone tubing is the material of choice.


We use Cole-Parmer peristaltic pumps at work quite a bit and generally use Tygon (PVC) or most often Norprene. The latter is stiffer than Tygon but has a longer lifetime. The pumps we use have 3 rollers inside of an acryilc or polycarbonate housing with the tubing between the two. The rollers pinch the tubing against the inside of the housing so the stiffness isn't a major issue as it may be with the pump you pictured.

spkrman15
07-11-2009, 09:25 PM
No rush Wes, It is just for my curiousity :)
Rob :)

gunbuilder
07-11-2009, 11:46 PM
Or do like the IV infusion system, build it with about 10 solenoids and fire them in sequence.

From the ones I have seen.

Thanks,
Paul

snowman
07-12-2009, 09:10 AM
Those aren't solenoids, they are just followers riding on a camshaft.

Lew Hartswick
07-12-2009, 09:22 AM
We use Cole-Parmer peristaltic pumps at work quite a bit and generally use Tygon (PVC) or most often Norprene. The latter is stiffer than Tygon but has a longer lifetime. The pumps we use have 3 rollers inside of an acryilc or polycarbonate housing with the tubing between the two. The rollers pinch the tubing against the inside of the housing so the stiffness isn't a major issue as it may be with the pump you pictured.
I worked on a bunch of those in the chem. and bio. departments at Penn State
I think the ones there had more than 3 rollers but it's been 20 yrs
since I was there. But they worked fine down to microliters per min.
And yes Tygon etc was the tubing of choice. The problem was mostly
electronics failure. :-)
...lew...

RTPBurnsville
07-12-2009, 12:07 PM
Thanks everyone for all the comments.... I saw the wiki photo and that is what prompted my question here in that the pump looked very simple for the price most places ask.

Wes - I would be interested to see a photo of your mechanical pump as well.

The omega site is not a place I would have thought to look. That looks like a source for reasonable pumps should I decide to buy something. However, I would like to make something or modify something that is already build just for fun.

The idea on using solenoids was very cool as was the thought of finding an old inkjet printer. I'll have to check craigslist to see if there are any local freebees.

BTW: I want to build a micro-drop style coolant setup for my Tormach CNC. The trico and acculube systems look great for the homeshop but for a grand, get real!!! The micro-drop concept appeals to me as it appears you get many of the benefits of flood cooling without the mess. I don't really care for the mist type systems as my shop is in my basement and having mist throught my house does not excite me.

Someone on one of these forum mentioned using an airbrush for coolant. I bought a HF version last week and I think if one combined the airbrush with a pump to produce micro-drops it would be a neat system for us homeshop guys to put together. The airbush by itself appears to be more of a mist type of application, much as one would expect.

Thanks Again,
Robert

Evan
07-12-2009, 12:20 PM
Someone on one of these forum mentioned using an airbrush for coolant. I bought a HF version last week and I think if one combined the airbrush with a pump to produce micro-drops it would be a neat system for us homeshop guys to put together. The airbush by itself appears to be more of a mist type of application, much as one would expect.


I use it to apply an ethanol mist when high speed cutting aluminum as it gives the best finish. Here is an example while CNC turning a parabolic metal mirror on my CNC mill using the high speed 4th axis attachment.

http://metalshopborealis.ca/pics3/8inch1.jpg

Weston Bye
07-13-2009, 08:34 PM
Here is my oil pump. The gearmotor turrns a short-throw crank, more like an eccentric. The rod bearing is bigger than necessary but I have plenty of them. The rod also serves as the piston, riding in a bore in the cylinder block. The cylinder block has the check valves built in, and pivots on a shoulder bolt. The cylinder and the end of the rod are submerged in the reservoir, a soup can, and the pump assembly rests on top of the can and is held in place by threaded rods and wingnuts. THe bore is 1/4" (edit) the stroke is 1/2".

http://img.photobucket.com/albums/0803/Weston/Oilpump4.jpg

http://img.photobucket.com/albums/0803/Weston/Oilpump1.jpg

http://img.photobucket.com/albums/0803/Weston/Oilpump2.jpg

http://img.photobucket.com/albums/0803/Weston/Oilpump3.jpg