Hey gang,
We have a couple older baghouses that we suspect have significant air leaks. Could these leaks be located with ultrasonics? Max dp around 10psi.

Alternatives? Thinking of soap bubbles but don't want to suggest something silly.

Thanks in advance.

Absolutely, go for it. Not only because I have done it, but when you think that airborne ultrasound can typically hear 5psi from .050" @ 50 feet, you should be able to hear it and locate the source.
I would like to hear back about your success, photos, as well, it would make a good article for our UPTIME Magazine readers as well.
Don't forget the duct work as well. As high volume air is moving through the ducting whethers it is being sucked or pushed through the ducting it creates at any opening, loose flange fittings, bolts, or rust hole...."IN-LEAKAGE".
Check out the JUNE/JULY issue of UPTIME Magazine. You will not see the actual bags, in the article pictures just the duct work. But, in some instances depending upon the configuration you can walk into the bag houses and scan the actual bags for leaks.
Jim Hall, Co-ed: UPTIME Magazine (ultrasound)
Ultra-Sound Technologies
(770) 517-8747
"vendor-neutral"

Hi Keith,

Without any doubt, if you already have ultrasound testing at your disposal you should try that before trying soap bubbles. Soap will be simply too time consuming, and there is no way you can test every potential leak site.

For ultrasound inspection to work there needs to be enough pressure in the system to create turbulent flow. As Jim Hall suggests, at 5 PSI pressure there is ample system pressure to produce some turbulent flow in most leaks. I suspect that with your system pressure of 10 PSI this will also be the case. You need to remember that at this low pressure the turbulent flow will be minimal, so while it may be possible, as Jim suggests, to hear 5 PSI leaks from 50', I doubt that those numbers were cultivated in a noisy baghouse environment. You will be faced with a lot of spurious and competitive ultrasounds which means that any leak in your 10 PSI system will be masked at 50'. More realistically, be prepared to do a thorough inspection of your baghouse from a distance of several inches. There are several advanced techniques for finding leaks in competing environments including shielding/positioning/blocking. Some of these are discussed at the "tips" section of our website. http://sdtnorthamerica.com/apps/tips.htm

Be sure that your headphones are rated for the noisy environment (not a walkman style, but an over-the-ear style) and can block out the competing audible noise of your plant.

Allan Rienstra
SDT North America
1-800-667-LEAK (5325)
"Vendor AND Customer Driven"

Thanks for the input guys. We'll give it a shot.

Allan, we're using your equipment...think the headphones are up to snuff?