Welding fume extractor problems

filtering.

advice?

Chris, are you sure that the high voltage power supply is doing it's stuff? Sounds to me that (assuming you have airflow through it) the plates aren't at a high enough potential. Electrostatic precipitation certainly works. CEGB (or whoever they are these days) have just installed vast ones on the DRAX coal burning power station making it one of the worlds cleanest coal stations. Also you only have to look inside a TV that's been in a house with smokers to see the crud they accumulate.

AWEM

I'd try giving the entire high-voltage part a thorough cleaning. Most likely, the weld fumes have totally gunked up all the insulators until the power supply is overloaded, and you get little to no electrostatic precipitation. You may have to scrub the insulator material with a toothbrush and something like formula 409 cleaner, then wash the whole thing off with a garden hose, and allow it to dry before trying it out again.

If you have access to something that can measure high voltage DC, you might then check to make sure it is really charging up. It needs to be at least 7000 volts to do much.

My solution to the problem was to get a TIG welder and ditch the stick process entirely. My sinuses are very sensitive to the welding flux.

Jon

As noted, check (carefully) the output of the power supply to the EP. EPs certainly can be very effective and should work fine in this application.

Possibly that "spare" slot for an extra filter is intended to have a filter in it and without this flow restriction the blower is moving the air too fast for the EP to be fully effective.

Are you sure Secomak is the manufacturer of the complete unit, not just the blower? Looking at their site it appears as though they might just make the blower.

Pete C.

From the look of the picture, this should be an excellent unit for your needs. Sounds like you have two different issues: air flow and filtering.

If the unit does not suck all the fumes in, something is amiss. With 1 hp and 6" duct, you should be looking at something on the order of

800-900 cfm. If the duct is within 6 to 12 inches of the arc, ALL the fumes should go into the unit. Tear the blower unit down, look for obstructions in the duct or blower. Make sure it is running at full speed (voltage correct?).

Electrostatic cleaners are very common in weld shops and bars (pubs). They will take out the airborne particulates very nicely. They are so effective that they are always dirty. I'd expect a used one to be filthy. A lot of the smaller units are designed so you can pull the plate assembly out completely, run it in an automatic dishwasher. Absent that, you may need to soak it in a very hot alkaline bath. Rind a suitable container, run as hot a water as you can get, add some boiling water from the teapot, disolve some (lot) automatic dishwasher soap, and let it soak. As others mentioned, look for cracked insulators, gunked over insulators, etc.

There are usally some extremely fine ionization wires (.010" to .015" nichrome)on the lead in side. If one of these is broken, it will short out the supply. Just pull the offending wire out, let it run, replace later.

A mildy dirty unit will give a high voltage crackle every now and then to tell you it is > Hi folks,

That's more machine than you probably need.

For most of us, "extraction" is just that. You suck it up and blow it out of the workshop. This machine is for portable use _inside_ a large building where it's important that the exhaust is "clean" because what you're blowing out is what the next poor sod along is having to breathe in.

As others have said, it's frighteningly high voltages and although there's always a user-serviceable part inside everything short of kidneys, you'd better know what you're about before you approach it. If in doubt, isolate things and just use it as a blower to the outside world -- cheap, and it'll do what you probably need most from it.

Whut Roy said -- except that if the ionizer isn't working the collector plates won't collect much. Try running the cleaner without the blower running. You should smell a faint ozone odor if the ionizer is working.

There'll be a high voltage diode in there somewhere. Those sometimes fail. Places that service electrostatic aircleaners should have replacements, and they can also sometimes be found in TV sets, microwave ovens and computer monitors. Some possible sources:

Makers of electrostatic cleaners include Honeywell and Trion in the U.S., don't know about in the UK.

Getting zapped by an air cleaner supply is not usually lethal, but it definitely hurts. I know a number of guys that have been bit by them, none that were buried as a result. Always keep one hand in your pocket when working with HV stuff.

That's so most of the HV will go directly to your family jewels - and help you to remember not to do that stupid trick again... Ken.

Thanks for all the advice. I ran a few tests on the machine today. The HV power supply is a potted epoxy unit with two leads emerging from it. So I figured that either one lead is positive and the other negative, or they both provide the same voltage with respect to earth. There's a little switch which turns off the HV power supply when you remove the side panel, so I wedged this closed. I wired up a 15 kV DC panel meter. I tried measuring the voltage between the two wires, and between each wire and earth, and also tried switching the polarity. But I couldn't measure any voltage. I also turned out the lights to see if a corona discharge was visible in the dark, but it wasn't.

I guess this could mean a few things:

1. The panel meter's broken.
2. The PSU is broken.
3. There's a loose connection.
4. There's a short circuit.

I doubt the meter's broken, but I can't be certain as this is the first occasion I've had to use it. I might try testing for a voltage with an ignition timing lamp instead. I can't see any loose connections (the wires certainly haven't fallen off, and they appear to be secure) and I can't see an obvious short circuit.

There's no mesh filter at all in this machine, but there do appear to be runners where something else could be fitted. Do electrostatic precipitators usually have a mesh filter too?

I guess if the worst comes to the worst, I still have a very nice blower which I could use for an extraction hood over my welding bench.

Thanks for the advice.

Best wishes,

Chris

I use this for welding in my garage:

15 ft of 6" dryer duct

a blower/ventilation thingy harbor fuddy dud has some, so does home depot. Its got a 3 position switch on the carrying handle/ round opening, intake... and square output....

I ran the duct to the top screen breather on the garage wall, this goes to the outside.

The air output, rectangle opening, when I am sitting down, welding helmet on, ventilates my face/front of hood. It sits under the welding table, with a 12 inch cover metal sheet, with a square opening, that matches the air output opening on the blower.

The cover metal sheet, keeps the plastic and other parts of the motor, from burns/melts of the slag, sparks, etc...

I have also tried a 36 inch square hood over the top of my welding table, with the dryer duct going to that outside vent. Did not work as well as the above. Still got some mild headaches.

This stuff is all for arc welding....mig and my tig fumes don't seem to bother me much, compared to the arc fumes.

If at all possible, you probably should weld outside in a well vented area with a big fan, that blows the fumes away from your position.

xman

Hi Chris, Forgive the top post but I think I recognise the unit, or at least its style. (I used to sell them many years ago) I believe it to be a Kemper unit. Probably an older model as I can't find one on their current websites. I suggest you find the local Kemper dealer and then find its longest serving salesman. Good luck!

Hi Chris,

Another simple test you could try is to measure the current draw/input for the HV supply. If it isn't drawing anything it probably can't be working (from your description though it didn't sound like it was working).

It doesn't look quite like the Kemper machines I've seen in the UK, although the colour is similar. The Kemper machines I've seen here are a simpler shape: just a plain cube like a washing machine. The Secomak plate isn't on the blower itself: it's by the main power switch. It gives the model number, voltage and current. The motor is made by Brook Crompton which suggests to me that the machine was probably made in the UK. It could be a Kemper though; it isn't clear. Maybe Kemper bought out Secomak's extraction machine division? If anyone knows more, please let me know.

Best wishes,

Chris

My expectation is that diagnosing this machine should be straightforward and should be based on logical analysis with a multimeter and a HV probe. Put it on bench, take it apart and see what works and what does not.

i

grounded.

machine

Chris,

I don't know if you've dabbled in electronics at all, but the main card of almost any non lcd PC monitor has a nice EHT source which could be pressed into service with a bit of ingenuity.

Or there are things like this on UK ebay:

AWEM

I've had power supplies die in every electronic 'furnace' air cleaner I've owned.

Bob

Thanks, Andrew. I'll bear it in mind. I'm not a stranger to electronics so it is an option.

I haven't done anything more with the fume extractor yet. I was a bit disappointed that it didn't work first time. I didn't need another project. Yet if the worst comes to the worst I can always just use the fan for an extraction hood.

Best wishes,

Chris