dear all,
we are in the market for ultrasound equipment. The 2 we looking at are Holroyd Instrument and the other is the SDT 170MD.Holroyd Instruments claim a "distress" function with trending as well as dB level trending which is "far more advanced" than using dB levels(distress) where as the SDT 170 only trend dB levels.

Could any of you explain how this technoligy work and how and how consistant dB level trending is. Holroyd had a demo at our plant and the technoligy seemed very aquirate. their distress trended steadily where as the dB trending were erratic.

Attached are the sites for the various equipment
http://www.holroyd-instruments.com/
[URL=http://www.reliabilitydirect.com/ultrasoundproducts/SDT-170.htm]

Your input would be greatly appreciated.

Hadrian

I"ve had good success using an Ultraprobe 9000 http://www.uesystems.com/products/9000.htm to compare like machines. I used it as another check to confirm a problem along with vibration. I also found a couple electrical problems with the ultaprobe.

We never really got a baseline/monitoring program going as our organization is very focused on vibration condition monitoring. But there is at least one very reputable outfit I know of that incorporates ultrasonic trending with vibration monitoring and they swear by it.

One thing I would suggest is having some sort of transducing headset to listen to vibration signals as data is taken (CSI has one if you use CSI equipment). I find this very valuable for bearings. If I think something warrents more investigation I go and get the ultraprobe.

Hugh Hackett

I am afraid I don't have any answers for Hadrian but I do have a question for Hugh Hackett. I have been considering buying a set of the transducing headphones you mention and I would like to hear more about them from you. I have to monitor a lot of medium and low speed rolls and I think they might be very helpful. I have to wear hearing protection anyway and it might as well be doing me some good.

Same story here Randle, I have to wear hearing protection so I figure why not wear the headphones. We use CSI 2120A analyzers and the headphone/adapter model number is 649.

I don't claim "amazing results"... to me it's just another tool in the tool box and it lets me feel a little more in touch with the machine.

HH

I'd recommend emailing Liane Harris ( lianesdt@sprint.ca ) She does certified training courses for SDT and is very knowlegeable about ultrasound applications. I believe she will give you un-biased advice.

One typical use for bearing lubrication is to listen via headphones as you grease the bearing - you can hear when it is enough. Then take an RMS dB reading as a baseline. From here, simply trend the ultrasound RMS dB level until you see a 10 dB increase. At this point it is time to grease the bearings again.

Hi Hadrian,

I have been using Holroyd Instruments products, which are quite reliable for bearing monitoring. I generally depend on DISTRESS readings. However, I have seen that DISTRESS is not too dependable for 2-pole & 4-pole machines, demodulation is superior. For 6-pole & slower machines, DISTRESS is better. Holroyd is also excellent for low speed applications. I don't know about SDT but I have had shootouts with the Ultraprobes & Holroyd came on tops each time.

Regards,

Aditya

At what intervals are you doing the ultrasonic testing ( monthly, quarterly, every 6 months)?They are wanting to set up routes and collect data on a certain interval. What would the best interval be? I am thinking quartely. Can you give me some of your ideas and intervals?

Micheal,
I am considering setting up the program to enhance my Vibration programme and to confirm some of my diagnostics.I have the equipment on order and included is a training course. I am also considering to having the various unit foremen using it to trend the deteriation on bearings, specially on critical machinery so to have maximum life from the equipment.

Hi Hadrian,

I can recommend Holdoyds, it is a very reliable monitoring technicue. I am not knowlidgeable about the others mentioned here.
The reason for the erratic dB trending might be because of different speeds of the machines or a veriety of other reasons that generate different dB levels.

Hadrian
UE Systems out of New York is holding a Ultrasound World Top Gun Conference at the Hilton Clearwater Beach Resort in Clearwater, Florida, October 24 - 27, 2004. They will have all their models on display along with the software for trending. There is also 5 free short courses offered. You can find more information on it at their web site www.uesystems.com