Archive for category Temperature

How do you keep production going when a control thermocouple burns out?

There’s no such thing as a fail-proof thermocouple. Over time, thermocouples fail. To compensate for that, a temperature controller will normally go into upscale burnout mode, and drive the furnace burner to low fire or turn down the SCRs.  But then, you have to deal with the downtime, rework, or even the potential of losing product.

Not long ago, a plant operator called to see if there we had a way to work around this burnout mode, so he wasn’t wasting time and materials.

His heat treat load had almost finished its final soak when the control thermocouple broke open. The controller, as expected, drove the furnace burner to low fire. The operator then popped the controller into manual mode, so he could nurse the load through the remainder of its soak cycle. He used the temperature reading on a recorder, fed from a second, unbroken thermocouple in the protection tube as temperature indication for the load.

If the situation had happened in the middle of the night, it may not have been handled with the same attention the day-shift operator had provided.

So, he asked if there was any way to have the controller automatically “fail over” to a second thermocouple. 

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Who wrote the book on pressure and temperature measurement?

Ever hear the expression, “They’re the guys who wrote the book”? 

When you hear who it is that “wrote the book”, they immediately gain authority over the rest of the “guys in the field”. It means they’ve taken the time to pull the fundamentals and inner workings into a centralized place, and they have the confidence in their works to share it with the world.

When it comes to pressure gauges and temperature measurement instrumentation…

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Are thermocouple heads and transmitters interchangeable between brands?

Ever wonder if you can mix brands of thermocouple heads, transmitters, or junction blocks?  The other day, I was trying to figure out if I could, and I ran into a spec I didn’t understand – DIN Form B. So, what exactly is DIN Form B, and how does it relate to thermocouple heads, transmitters and junction blocks?

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