Early in my career I did tensile testing on adhesive coupons. I was running an experiment to simulate heating and cooling cycles on a bond. I had a nice big thermal chamber from the 1960’s, lined with heating elements (and undoubtedly asbestos), a big old dewar of liquid nitrogen, some thermocouples, and a PID controller the size of a German Shepherd.
Problem is, cold air sinks. My samples are sitting on the bottom of this huge chamber and their temperature is fluctuating wildly every time a bit of LN2 is added. The ancient PID controller cannot cope with my shitty test setup, it’s trying to turn on the damned heaters to control the temperature when I’m trying to go cold and this is a multi-hour test and I just want to go home.
But… I have a cardboard box. Nice, insulative cardboard, just the right height to get my samples off the floor of the chamber and into a zone where the temperature is more stable. I am brilliant! Cardboard box deployed, I can finally begin my thermal cycling.
I learned a few things that day:
thermal cycles include both hot and cold phases
the floor of the thermal chamber has much less temperature stability while cooling AND while heating
specifically the floor contains a heating element and gets ridiculously hot
cardboard combusts at a temperature much lower than you might expect
opening the door of a smoking thermal chamber to investigate allows in a rush of oxygen
rapid introduction of oxygen to a smoldering cardboard box leads to very large exciting pretty flames
fire extinguishers leave a fine dust of particles all over everything that you will be cleaning up for MONTHS
Sounds like my first internship. Huge, multi-million dollar test loop for compressor validation. Shortly after I left one day a 1/4 inch tube fitting on top of the compressor, part of the oil system, sheared off during a test. While I dont remember the oil pressure I do remember the video a coworker took of the incident.
Oil geysering all the way to the 40ft high ceiling. For 45 minutes.
I get back the next day and the whole test loop is covered in oil. Footprint-wise think two semi trailers next to each other. Oil on the floor, oil in the (water only) trench drains which they had dammed quickly, oil on thousands of feet of piping.
Let me reiterate; I was the intern. Aka, my job description now included “waste oil remediation.” It took a week-ish for your boots to stop sticking as you walked and far longer than that to clean the piping.
To top things off this happened in winter and the oil viscosity reflected the cold conditions. Thus as spring and summer rolled in and the temperature increased the pipes started…dripping. Honestly this was years ago and I suspect they’re still wiping oil up here and there.
Early in my career I did tensile testing on adhesive coupons. I was running an experiment to simulate heating and cooling cycles on a bond. I had a nice big thermal chamber from the 1960’s, lined with heating elements (and undoubtedly asbestos), a big old dewar of liquid nitrogen, some thermocouples, and a PID controller the size of a German Shepherd.
Problem is, cold air sinks. My samples are sitting on the bottom of this huge chamber and their temperature is fluctuating wildly every time a bit of LN2 is added. The ancient PID controller cannot cope with my shitty test setup, it’s trying to turn on the damned heaters to control the temperature when I’m trying to go cold and this is a multi-hour test and I just want to go home.
But… I have a cardboard box. Nice, insulative cardboard, just the right height to get my samples off the floor of the chamber and into a zone where the temperature is more stable. I am brilliant! Cardboard box deployed, I can finally begin my thermal cycling.
I learned a few things that day:
Could you have extinguished the fire with the LN2? Not that I would have reacted any better in the moment.
Maybe… it was a big enough fire that I was worried about triggering the sprinklers / fire alarm so I wasn’t in any mood to experiment further.
Sounds like my first internship. Huge, multi-million dollar test loop for compressor validation. Shortly after I left one day a 1/4 inch tube fitting on top of the compressor, part of the oil system, sheared off during a test. While I dont remember the oil pressure I do remember the video a coworker took of the incident.
Oil geysering all the way to the 40ft high ceiling. For 45 minutes.
I get back the next day and the whole test loop is covered in oil. Footprint-wise think two semi trailers next to each other. Oil on the floor, oil in the (water only) trench drains which they had dammed quickly, oil on thousands of feet of piping.
Let me reiterate; I was the intern. Aka, my job description now included “waste oil remediation.” It took a week-ish for your boots to stop sticking as you walked and far longer than that to clean the piping.
To top things off this happened in winter and the oil viscosity reflected the cold conditions. Thus as spring and summer rolled in and the temperature increased the pipes started…dripping. Honestly this was years ago and I suspect they’re still wiping oil up here and there.
Brutal, oil spills are the worst, even in really small volumes. That stuff will crawl straight up a wall.
Brilliant writing, funny story told well, 10/10, would set my experiment on fire for.