In 1968, give or take a year or two, I was working in
Houston at AMF Tuboscope, a pipe inspection company, developing new technology
for inspecting oil field pipe and pipelines.
We had a sister company in Canada, North American Inspection, that
specialized in field inspection of transmission pipelines. In particular, they were radiographers who
examined the pipe welds between joints of pipe before the pipe was buried in
the ground. To add to their capability,
we took on a project to develop an internal crawler robot that would carry a
radioactive source along inside the pipe and deploy it at each girth weld where
film had been wrapped around the outside of the weld. Upon development of the film, the weld quality
could be determined and cracks, porosity and other defects identified. I was project engineer of this project and
did the electronic design for the control system.
The crawler was a self-contained, autonomous device powered
by an on-board 24 volt battery. It was
driven by a high-torque DC motor connected to a drive wheel. The control system, consisting of discrete
analog and digital IC’s was contained in an aluminum housing about 8-inches on
a side. Control knobs and switches on
the top of the housing permitted set-up of the device. The radioactive source was a cobalt isotope
housed in a 200-lb. holder of spent uranium or lead. When the robot sensed a weld, it stopped and a
separate drive motor would drive the isotope from its holder into position to
expose the film for a preset exposure time then it would be retracted back into
a safe position and the crawler would move to the next weld.
The system was built and checked out in our Houston lab,
then taken to a field site in Louisiana where it was used with North American
radiographers for training before it was shipped to Canada. All went well and the system was turned over
to the North American company office in Calgary. Not unexpectedly, we got a call within the
next few weeks that there were problems with the control system. I bagged up some spare parts, a few tools and
a couple of test instruments and headed to Calgary. As I went through customs, the Canadian
authorities were interested in my little Sony battery powered oscilloscope and
my function generator. I explained the
situation, but they said I could use Canadian instruments and confiscated my
gear. I pled my case to my North
American contact, the office manager there, and he said he would see what he
could do. I told him I need some
electronic workbench space to trouble shoot the system.
He came back later in the day and said, “I’ve found you a
place to work. It is the repair shop at
a TV store. The Earl of TV would close
at 9 PM and I could use his shop all night long.” OK, maybe this won’t be too bad. I showed up at The Earl of TV and sure enough
he had a work bench. I had the
electronics box from the robot and got ready to do my trouble shooting. First problem: The electronics required 24 VDC and the shop
had only a 12 volt supply. I dug around
through everything in the shop, but no luck.
He did have some pliers, though, and fifteen minutes later, the 12 volt
supply, in series with the battery from my rent car gave me the 24 volts I
needed. I thought surely there must be
an audio oscillator or some such generator to produce an AC test signal. Sorry, no oscillator, but I did find, in his junk drawer, a filament
transformer that let me produce at least a 60 Hz sine wave of a low
voltage. His oscilloscope, I will never
forget it, was a Jackson CRO-2. It did
have a display, but no DC coupling. If you
connected the probe to a DC potential, the trace would sail off the screen and
slowly drift back as the input capacitor charged up. I won’t go into the agony of trouble-shooting
digital switching circuits with an AC scope, but it was not fun. To cut to the chase, I did survive the night
and got the box working in time to turn it over to the North American crew the
next day.
One final touch: On
the day I was to return to Houston, I decided to pay a courtesy call to the
Tuboscope Calgary office. They were
doing oil field inspections completely independent of the North American
Inspection Company. When I drove into
the yard at the Tuboscope location, I saw a neat looking van painted in the
company colors. It had a Texas license
plate. I said, “Is someone here from the
home office?” Oh yeah, that’s the
Quality Control van. They are here to
check our equipment. The van had racks
of power supplies, scopes, signal sources, etc. If only I had known. But then I’d never got to meet the Earl of
TV. Over 20 years later, on another trip
to Calgary, I checked a phone book and sure enough The Earl was still
listed. I really doubt that he ever
repaired a TV, though.
