We are starting to think about creating "steam trap" rounds. Initially, it was thought that Thermography might be the best choice for this. But I'm wondering if Ultrasonic might be a better choice, especially for those traps that are accessable without ladders.

I would be interested in your experiences with either or both of these technologies use on steam traps.

Thanks You.

Don,

I would be interested in hearing what others have found, but my experience has been better with ultrasound. Temperature is of course a very quick and easy indication of plugged traps, but it can be challenging to determine if a trap is blowing through or simply responding to a lot of condensate in the system using temperature. Also, with insulated pipes, it is more practical to put a small hole in the insulation to insert the ultrasonic probe than to remove insulation for an IR scan (and have to worry about he "e" value). There are also expensive analyzers made specifically for steam traps. But we were very successful using an IR gun to check for cold pipes (plugged trap) and an ultrasonic gun to listen to the traps.

I have lots of experience with steam trap inspections and found that the best way to inspect traps is by using a combination of both IR & UT.

Also, you should have good knowledge of how each particular trap operates and their failure modes.

You can see an example of a good and bad disc type steam trap on my web site's show and tell section:

http://www.tdlir.com/show001.html

Hope this helps.

Regards

Don K
I agree with the previous comments about using both technologies for inspection of steam traps. But to use an IR gun is a little different than using a thermograph imager. The IR Gun is less visual than the imager. As AlanH2 used the IR Gun on cold pipes is a good application, but when looking at the steam traps and lines, as they blow, the visual from a thermograph imager is much more conclusive as you see at Sonny's tdlir web site. I have also used ultrasonics and depending on service conditions ultrasonics could be a better application than thermographs. These two technologies really work well together and if you have a choice get both and you will not regret the decision. For me, it would be a hard decision to chose one over the other. Allot of other factors would have to be looked at for that decision.

Another thing we considered - ultrasound is better, when you can get to a trap, but we have many traps which would require a lift or ladder to access. For the time saved, we used thermography on poor access traps.

I consider both to be a must in steam trap inspections. I have detected Problems with ultrasound on good looking traps thermally, and what sounded like a normal operating trap found not functioning properly with IR. It really does tell the whole story using both.

Craig

I am more familiar with ultrasonics, having trained on it for the past 8 years to various organizations for numerous applications including steam trap testing. In one service organization ultrasound is used to monitor 10,000 traps on the Canadian pipeline. Each trap is tested in contact with a solid probe to verify its operation 4 times per year...that's 40,000 tests. Speed and ease of use for testing as well as performance make ultrasound the tool of choice in this case.

With regard to the original post about using ultrasound and infrared together, from what I hear in industry and from service providers is that combining these two technologies has become the standard for steam system inspections. Craig Casler's posted response is a great example, and a thermographic image provided to me BY Craig is posted at SDT's website here:

http://www.sdtnorthamerica.com/apps/steam.htm

Regarding Stan Riddle's post, he states that Ultrasound is not practical for steam traps that are out of reach. Agreed, this was a problem, but I received a success story from Nestle Plant in Wisconsin. They are using SDT 170 with Laser Sighting on Parabolic Dish to do Ultrasonic testing on steam traps at distances of 20' and more. As soon as I find his write up I'll post it.

Parabolic Disc? for steam traps huh..?

Do not know, the SDT but probably the laser is for aiming.

The parabolic concentror is used for airborne ultasound detection. Great for high voltage line (corona), steam/gas/fluid/air leaks in piping etc.. If they are detecting on a trap somewhere in the air, it is already too late, they are localizing the leak

When testing steamtraps the sensor is mounted on a stick, which comes in contact with the metal. Compare it with the doctor using a stetoscope.

Allan, the parabolic dish with laser sighting sounds like something Jack Bauer would use on "24"!

Actually, it would be a GREAT idea. My only concern would be where we have banks of traps together. It might be hard to differentiate, but thermography or a contact ultrasonic would be fine.

It is a good place to start. Please post if you find that information.

Thanks,
Stan Riddle

A parabolic dish like the CTRL PowerBeam 300 uses a laser to pinpoint the direction of reception. The receiver's microphone is used to detect ultrasound produced by steam traps, corona discharge, etc. The PowerBeam detects ultrasound within 1 degree from center of the direction aimed. Therefore, pinpointing a particular steam trap from 20 feet or even 40 feet (depending upon sensitivity of sensor and interfering ultrasounds) is possible.

I would be surprised if the parabolic reflector would work in most cases. I've looked at quite a few traps in Infrared and with Ultrasound. I agree that these technologies used together are very effective. Ultrasonic monitoring is done in the contact mode, since the source of ultrasonic energy is the turbulence due to the steam flow and velocity. This ultrasound does not propagate well through multiple media, such as from steam to pipe wall to air. Using airborne ultrasound (whether standing next to the trap, or aiming at a distance with a parabolic reflector) will not be very effective. In most cases, I rely on the IR primarily, and will use a contact extension rod or removable contact probe on the end of a stick.

It is worth the extra effort to get close enough to contact the trap when a leak is suspected, to positively identify the malfunctioning trap. This is especially true when there are multiple traps discharging into a common header, and the leaking trap backfeeds the drain lines, making them all look hot. In those cases, Ultrasound may be necessary to figure which one is actively leaking, and which ones are being backfed steam.

Rich Wurzbach
rwurzbach@mrgcorp.comMaintenance Reliability Group