Sciencemadness Discussion Board

Small recirculating pump

starman - 16-8-2009 at 17:24

I have been trying to source a small,inexpensive pump for recirculation of catholyte/anolyte in a small cell.Given that it wont be expected to deal with anything too aggressive(dilute acids,dilute ethanolic HCl) I was hoping that something along the lines of a cheap aquarium pump would suffice(I think the innards are mosly HDPE or PP).Unfortunately they all seem to be submersible,not inline connectable.I did find one outlet in the UK,just the right size(flow rate about 800ml/minute)polyacetal impeller and stainless housing and fittings but it was well over my budget.
If any member has come across an appropriate cheap pump or has modification suggestions to something on the market I'd be very happy to hear input.

chemrox - 16-8-2009 at 18:51

Maybe a small peristaltic pump..?

watson.fawkes - 16-8-2009 at 22:22

Quote: Originally posted by starman  
I have been trying to source a small,inexpensive pump for recirculation of catholyte/anolyte in a small cell.
You might be able to use one of those "drill pumps" that have hose connections and a shaft to chuck into an electric drill. The problem you're likely to have is chemical attack of the metal drive shaft. I suspect that you'll have that problem with any inexpensive pump, since chemical resistance just isn't on their list of design criteria.

If your flow rate doesn't need to be very high, you might be able to rig up a bubble pump.

starman - 18-8-2009 at 17:08

Quote: Originally posted by watson.fawkes  
I suspect that you'll have that problem with any inexpensive pump, since chemical resistance just isn't on their list of design criteria.

Yes,probably over optomistic,given that they are construced of the cheapest adequate materials.
@CRX - good idea.Why didn't I think of that?Only ever thought of peristaltic for dosage control.Can't afford a new one,but maybe ebay secondhand or even an entertaining DIY.

jock88 - 22-2-2014 at 15:42


What do you guys think of using these things for pumping in the lab?

http://www.ebay.co.uk/itm/Lot-of-6-IMED-Volumetric-Infusion-...

IrC - 22-2-2014 at 17:30

http://www.goldmine-elec-products.com/products.asp?dept=1215

You might look at these pumps.

macckone - 22-2-2014 at 19:30

You may try a boat store, some of them carry bilge pumps that
are sealed against salt water, that will probably work with mild solutions.

jock88 - 23-2-2014 at 14:05


Those pumps will not handle corrosive fluids. You need (unless you are going to pay big bucks) a peristaltic pump.

macckone - 24-2-2014 at 22:18

Salt water pumps will work with mild chemicals.
10% NaOH, Acetic Acid, things like that.
They will not with stand really strong things like concentrated sulfuric acid.
Depending on the pump it may or may not withstand weak ethanolic HCL.
But generally most of the parts are polypropylene or polyethylene and no
metal parts in direct contact with the water flow (salt water is very corrosive
when flowing with entrained air).
I would actually be more concerned about the seals on the shaft being attacked
by ethanol than direct corrosion.

Peristaltic pumps are necessary for the more concentrated stuff like sulfuric
acid, which will attack most metals and plastics.

jock88 - 25-2-2014 at 11:43


The pump above also has metering capability. You tell it you want to pump so such per hours and it will do it built in. You can also set total amount to pump. It dectects bubbles in pipes (may be a disadvantage but it can be overriden). Batter backed up if power failes and all for cheap.

chemrox - 25-2-2014 at 16:02

I have a small peristaltic pump I was going to use to recirculate cooling water. I could let you have it for $42 + shipping.

jock88 - 25-2-2014 at 16:55


I have a small peristaltic pump for pumping condensate from a air conditioner (its original use).
I think that folks here should make use of the cheap reliable infusion pumps + the other functions they contain.
Cheers

ZIGZIGLAR - 25-2-2014 at 18:36

Peristaltic pumps are great. The medium only ever comes into contact with the hosing, so you can spend less over all then you would have to on a pump with chemical resistant casing and internals. It also simplifies cleaning and minimises or eliminates common issues with other pumps like (re)priming, air entering the system, damage from running dry, total disassembly of pump body for cleaning etc. If all you are doing is moving potentially corrosive liquid from A to B, Peristaltic is the goods.

EDIT: I should add - if the stuff you're recirculating isn't particularly viscous or corrosive, you can find really cheap inline pumps on ebay and the like. I believe their alias is "little brown pump". They are usually 12v and come with no power supply, but are easy enough to solder up to an adapter. I use one of these to recirculate water in a hot water supply kettle, to ensure consistent heating. The flow rate is sufficient even with half inch hose. Priming is the biggest issue with these, but easily dealt with if addressed correctly.

[Edited on 26-2-2014 by ZIGZIGLAR]