In my previous life as a manufacturer’s rep, I was asked to travel to Ontario, Canada to work with a well known bus manufacturer. As so many other manufacturers would do, this company assembled a large part of the bus in Canada. Then they would mount the assembly atop a semi-trailer for transport into the United States (North Dakota) to finish the job.

However, certain manufacturing tasks, that had to be performed outdoors, could not be scheduled due to the cold and the amount of snow that might build up during those cold winter months in Canada and North Dakota.

I once visited Sault Ste. Marie, Ontario to train workers, in a steel mill, how to use Ultrasound in February 2006. I remember the bitter cold! I am definitely not a cold weather person. Nor, do I drive well on ice. Lets say I drive on ice about as well as most of you drive on a rain slick highway. This old southern boy will travel to Florida and drive on rain soaked highways and roads rather than to go to the northern states in the winter. In fact, when Atlanta’s weather gets too cold, believe me, I find an excuse to drive south. Brrrrrr! I get cold just thinking about it.

Anyway, bottom line, this company could not perform the wind/water leak tests on the bus chassis during those cold Canadian and North Dakota months.

When I arrived at the bus company, I asked the lead engineer what test they used when looking for wind/water leaks. He told me they used “smoke stick candles”.

Cha-ching! (the sound of a cash register) Wow! This company manufacturers 1000 buses a year! A smoke stick candle would cost them $12.00 each and they used two smoke stick candles per bus. Two smoke sticks per bus? That’s $24,000.00 a year in smoke stick candles alone!

The test they perform, at this point in the manufacturing process, is a preliminary test of the bus cabin, floor boards and wheel wells. They are making sure all rivets are inserted in the floorboards and sealed properly. They would also test around the “hump”, the wheel well area of the bus in which the rear wheels are located. Here, if the metal was not assembled properly, you might receive road noise, water, exhaust fumes as well as dirt particles intruding into the cabin whenever the bus is on the road. A second test would be performed when the bus was in the United States and almost complete.

Other locations to be tested on the bus chassis, early in manufacturing, were the windshield, doors and passenger windows. Testing these areas with components not yet installed, required the technicians to button-up all access doors and windows within the bus with test plugs or test panels. 

I introduced them to Airborne Ultrasound, the receiving hardware and the “tone generator” device used to produce an ultrasonic signal.  I placed a tone generator in my demo-case and latched the lid with the tone generator inside and turned “on”. I then took the rubber focusing cone from my kit and placed it over the scanning module to pick-up the high-frequency sound being emitted from inside the box. I quickly demonstrated how easy it was to find leaks in my equipment case, a Zero-Haliburton Case, with a groove & seal installed in the upper lid of the box. I pointed at the case and detected the sound from the tone generator pouring out of the corners of the box, the combination lock, and a spot on the hinge.

I also mentioned another advantage of using airborne ultrasound, instead of the smoke stick candles, to them. The high-frequency (ultrasound) short wave signal (1/8”-5/8” long) is directional, unlike the smoke stick candle whose smoke will take “the path of least resistance”.

When using the smoke stick candles, the bus would fill with smoke and the technicians would then look for smoke pouring/exiting from the bus at the leak sites. However, during the cold winter months, and, depending upon the height of the snow banks, this procedure or test could not be performed outdoors. Performing this test indoors was not a good idea either due to the smoke. Try explaining the smoke to an over zealous Fire Marshall as the smoke is pouring out of your building.

Airborne ultrasound for this application included the use of a tone generator or multiple tone generators. Simply placing these tone generators inside the bus and turning them on prior to closing up the bus, would send high-frequency sound waves throughout the interior of the bus, flooding the inside with sound that could be heard using the ultrasonic receiver, through the leaks, on the outside of the bus.

I assured the technicians that they would never need to buy another smoke candle if they would simply purchase the airborne ultrasound system. To my surprise, they made a decision to purchase 5 ultrasound devices that day. They spent the equivalent of a year’s worth of “smoke stick candles”. CHA-CHING!

Now, take the time to think about this application. Can you think of other applications that would warrant the use of a tone generator?

Do you need help understanding how to use your ultrasound instrument? Are you missing leaks that you should be detecting? Call me for a quote to come to your site or visit my website and reserve a seat at one of my Ultrasound Workshops or Ultrasound Level I Certification Classes.
Call (770) 517-8747 to reserve your seat.......  Jim Hall, President of Ultra-Sound Technologies is also a Contributing Editor of Uptime Reliability Magazine (ultrasound segment). Ultra-Sound Technologies is available for one, two or three day ultrasound workshops, as well as a Level I & II Ultrasound Certification Class.  Jim has been in the airborne ultrasound industry over 21 years. Jim has provided airborne ultrasound training for many Fortune 500 Companies, including the electrical generation, pulp & paper, petro-chemical, manufacturing and transportation industries.  A 17 year civil service veteran, Jim served as an aerospace engineering technician for Naval Aviation Engineering Service Unit (NAESU) and with the Naval Aviation Depot Jacksonville Florida (NADEP). UST is a Disabled Veteran Owned, Small Business.

Best Regards,
Jim Hall, PresidentUltra-Sound Technologies   Ph:  (770) 517-8747jim.hall@ultra-soundtech.com