OT: Miniature Fluid Pumps

[DigiTan]

Sorry, if these mechanical questions are a little off the subject, but I'm in search of a miniture water pump and so far I've done nothing but tread water.

Basically, this is for a circuit etching tank. I need at least three fluid pumps to fill/drain the etching tank with water, developer, and etchant. The problem is that since the etchant is involved, it can't contain any metal or soluable adhesives.

The device I had in mind was something like this centrifugal design, but maybe smaller. I tried a **broken link removed** using solenoids, but I couldn't get the power I wanted out of it. You might say the efficiency 'sucked.' :lol: Anyway, any device that can drain 1 quart in less than a minute would be useful. I'm not picky about power requirements.

And I've already tried some aquarium stores but they only sell those open 'waterfall' type pumps. I need a sealed design because of the Cl gas. Any suggestions?

 

[bmcculla]

Certain medical pumps use a rubber tube and a wheel with little rollers along its edge to pump fluid with no contact between the fluid and the pump mecanics. The rubber tube is in a U shaped cutout that the wheel spins in. The rollers along the edge of the wheel roll along the tube compressing against the U and forcing the fluid through the tube.

 

[mechie]

Peristaltic Pumps

The pump that bmcculla is describing is a rotary Peristaltic pump.
I have seen pumps built this way for metering tiny flow rates (ul/min) upto big gallons/min jobbies driven by 3 phase motors.

You need to find a tube capable of surviving the repeated crushing it gets from the rollers - we use Tygon(tm) which gives several months of continuous use before it splits and messes the cabinet up- in industrial chemical analysers.
You also need to fabricate a rotor with spring-loaded rollers or you could build a linear Peristaltic pump - a straight tube and a series of five or so 'fingers' that sequentially push against the tube, maybe cam-driven.

 

[FRIED]

**broken link removed**

 

[chemelec]

Try This Company, They have a Wide Variety of Pumps and they are pretty good Quality. Some are Magnetic Driven for Corrosive Chemicals.

https://www.littlegiant.com/

I was Quite Pleased with the one I bought.
Hope it Helps........Gary

 

[JimB]

Try the windscreen washer pump from a car.

JimB

 

[DigiTan]

Thanks. There are few medical supply stores in the area so hopefully I can I find a useful retailer. Does little giant have miniturized versions of their magnetic pumps? The ones I saw are very large and run off mains. Also, I was thinking of using a wiper fluid pump but I wasn't certain of whether those were able to handle ferric chloride. Are those designs also non-corrosive?