In Praise of Ultrasonic Leak Detectors

[awemawson]

I've been chasing leaks on my compressed air distribution system. Nothing massive but enough for the compressor to cut in a few times during the day even when no air is being used.

My air distribution system spans six buildings, uses blue MDPE water distribution pipe, and probably has upwards of 100 joints in the form of elbows, tees etc.

Now I've always kept a 'leak detector bottle' - just a hand spray with diluted washing up liquid - and that's been adequate, but recently it's failed me - I've been unable to pinpoint the leak / leaks. They are obviously very small but need rectifying.

Recently watching a YouTube video extolling the virtues of Ultrasonic Leak Detectors, but finding that the model they used was north of £400 got me thinking that just maybe the cheap Chinese knockoffs on eBay and Amazon might be worth experimenting with. To cut a long story short I bought the cheapest on UK eBay for £26.99 and it was delivered this morning.

So - wack a battery in and see if it works. YES - in the first 5 minutes I found three minor leaks that the soapy water hadn't revealed - and that was just on a cursory test rushing as I was late for lunch !

Would I recommend it - certainly. Perhaps not up to professional robustness, but for my sort of use it's ideal.

This is the one I bought: https://www.ebay.co.uk/itm/394090785284

[Brass_Machine]

That's pretty cool. Something I would have never thought of. Will be plumbing the shop for air, I can see that it migh tbe a worthwhile spend.

Thanks!

[awemawson]

Eric this was triggered by my push to reduce electricity consumption - no point in have a compressor running unnecessarily but the convenience  of having air on tap everywhere is a great benefit.
 
I've been round the system once more this time tightening detected leaky joints, and fingers crossed all are air tight. The leaks were absolutely tiny but never the less causing issues.

I'd have given my eye teeth for this back in the mid 1970's when I was working on Burroughs 'head per track' disks.  (All of 2 Mbyte but fast access) They had 100 heads on each side of a 20" platter, each aerodynamic  head 'flown' on air and pressed onto the surface by a 60 psi piston arrangement. As you can imagine leaks were rampant, and as the heads were inside the ultra clean enclosure any opening up to find leaks required many hours of purging the enclosure through a special 'absolute filter' which was fine enough to remove viruses we were told !

[Brass_Machine]

...

I'd have given my eye teeth for this back in the mid 1970's when I was working on Burroughs 'head per track' disks.  (All of 2 Mbyte but fast access) They had 100 heads on each side of a 20" platter, each aerodynamic  head 'flown' on air and pressed onto the surface by a 60 psi piston arrangement. As you can imagine leaks were rampant, and as the heads were inside the ultra clean enclosure any opening up to find leaks required many hours of purging the enclosure through a special 'absolute filter' which was fine enough to remove viruses we were told !

Reminds me of working on Vacuum Tape drives back in the 90s... Sometimes it felt like I was more of a mechanic, then an IT guy. Chasing down leaks. Replacing vanes in the pump...

[awemawson]

Yes been there as well - Ampex TM7 & TM9 vacuum column tape drives - superb set of three nested control loops (two columns and the capstan) - great fun. We had proper computers that LOOKED like a computer in those days 

[Spurry]

Thanks for the tip Andrew. It sounds very much like an EGHSHO item.  , so have ordered one.
(Every Good Home Should Have One)

[Sea.dog]

Me too. You never know when it might come in handy, do you? 

[awemawson]

Well this morning i altered a bit of my air plumbing so that I could bring it up to pressure, close lever ball valves to isolate it from the compressor and yet still have a pressure gauge connected to monitor the pressure.

Pumped it up to 100 psi and left it to sit. Still bang on where it started so it's looking good on the 'cured leak' front ! I'll leave it over night before opening the Champagne and firing off the rockets 

 

[David Jupp]

Ultrasound leak detectors can be very sensitive - I've used an old one to locate leaks on car air-con system.