windscreen washer pumps

I know some of you use these - my question is can they be left running for some time or will they burn out?

Windscreen washer pump will pump litres/minute at 12 V and they get warm quite quickly. I run mine at about 2-3 volts to have a constant dribble of coolant. At this voltage the pump hardly gets warm even after extended running.

At 12V the pumps are designed for intermittent use but at lower voltages they can be run continuously.

Mike

thanks - im intending to make a water fed torch for my tig set - flow can be fairly slow so it might just work

There are plenty of small 12V pumps available that are designed to run continuously for not a lot of money and may be better suited to this application. The pump unit on my TIG set not only includes a tank and pump it also has a cooler and fan.

Bob

Some time ago I made a hydroponics set-up for a horticultural trial (growing lettuce, for the suspicious among you!) using four of the cheapest screen washer pumps Ebay could find - Vauxhall Astra IIRC but not sure. Anyway, they ran for just over a month continuously (24hrs) at approx 5V (so a lot slower than full speed) and there were no failures and no noticeable degradation in any of them. So for e.g coolant I'd imagine they should give decent life unless you're on your machine all day, every day...

any idea what the current draw is?

Hi Fizzy,

The pump I use draws about 400 mA at 9V. At 12 volts the current draw will be a little higher and at a guess around 600 ma.

Mike

I have used the washer pumps as a cheap coolant system but have replaced the pump 3 times in the last 2 years.because of failures. They work but are not a long time solution.

Paul.

Another couple of ways to do it, both car fuel pumps, one an electric pump, or two a mechanical pump, you would need an electric motor with a cam on the shaft, there was an article in ME a few years back, but it wouldn't take much imagination to devise something. I was just looking at a pump yesterday, and thinking I ought to use it, I think that the pump I have I should put a lighter spring on the plunger.

Ian S C

There seem to be two types of washer pump. The one I have been using intermittently for about ten years has Tufnol (or similar) gears. Some of them use plastic gears that can be attacked by the soluble oil, they are inclined to swell and the increased friction overloads the motor.

I don't remember if there is any external difference but it shouldn't be too difficult to make new gears if necessary. Before using one I would dismantle it and see which type of gears it uses.

Russell.

I'm using a facet 12v fuel pump feeding neat cutting fluid, works fine for me.

Paul

Ian et al - I thought you couldn't use a fuel pump for water as there is no lubrication? Otherwise this might be what im looking for.

A fuel pump for an older car (<1990) will rely on a rubber diaphragm and metal flap valves, so the only problem with water is going to be corrosion.

Why not put a tank (eg plastic) on a high shelf and just run a tube to your device, collecting the (warmed) water below for re-use?

Cheers, tim

I've got a fuel pump left over from bike racing days, I like it because when I close the tap, it shuts off automatically. It's a pretty standard Kawasaki ZX pump, obviously it's not submersible and I don't think it's self priming but it seems to get on just fine.

If you choose to use an electric motor driving an eccentric for a mechanical fuel pump, usually they only deliver about 2 psi for a petrol version, or 5 -7 psi for one intended to feed the rotary injection pump on a diesel engine. (In Line injection pumps are often fed at about 10 -15 psi). You are not really interested in pressure, more in delivery volume, so anything should be OK.

My coolant (cutting lubricant) system uses a gravity feed, with about a two foot head to a needle valve (which spends most of its life nearly closed) and a 1/16 jet, so no great pressure is essential.

The inlet and outlet valves are usually Tufnol, so the only parts at risk of corrosion are the alloy parts of the pump body, or the brass gauze present under the steel top cap (if one is fitted)

An electric feed pump, of the SU type will run off 12 volts continuously, as it does in a car with a carburretor.

Got to be worth a try

The feed pump, usually tank mounted , in a petrol with fuel injection, operates at a much higher pressure, maybe upto 60 psi, so probably not such a good idea.

Best of luck!

Howard