The transcript of the video is listed below and covers how to install temperature probe into a thermowell - in this instance for a brewery.
Hi, I'm Matt Nowick, founder and president of Brew Data and Nowick Sensors.
I'm on location at Cedar Rapids newest brewery, The Quarterbarrel.
The topic of today's video is how to install a temperature probe into a thermowell.
A common complain that I hear from brewers is that one of their temperature probes isn't reading the correct temperature.
This might be due to a calibration issue or a wiring problem, especially for RTD's. But the most common reason that I've seen is that the temperature probe is not installed correctly inside the thermowell.
Here we have a typical thermowell, welded into the side of a fermentor. It protrudes inside of the brewery fermentation tank far enough so that the end of the thermowell is at the same temperature as the liquid that surrounds it.
Here is a temperature probe, in this case its a Nowick Sensors solid state probe.
The sensing element is at the tip of the probe, so the end of the probe must be in good thermal contact with the bottom of the thermowell.
This particular temperature probe features a spring loaded fitting that helps to hold the tip of the temperature probe against the bottom of the thermowell.
You can see it moving about 1/2” or so.
In order to accurately measure the temperature inside of the tank, the temperature probe must be in firm contact with the bottom of the thermowell. A gap of even a millimeter can cause an inaccurate reading.
Thermowells generally come in standard lengths, so in theory if one uses a standard length probe and a standard length thermowell everything will work.
But that's theory. In the real world this often isn't the case. Sometimes the thermowells might be metric or they might have an extra coupler attached. The best way to make sure that the temperature probe is going to fit is to measure the inside length of the thermowell.
An easy way to do this is to use a skinny measuring tape or some stiff wire.
So let's measure this thermowell......
So this thermowell measures 9 1/2 inches to the end of the coupler.
So lets compare this with our probes....
Some sensors, like ours, can be extended or trimmed in the field, but most cannot.
There is one more thing that I want to tell you about.
There is a substance commonly called heat sink or thermal compound that is designed to fill very small gaps like 1mil. In other words to smooth out surface roughness. Don't use it to try to fix a probe that's too short. You will make a great big mess and it won't fix the problem. Just buy a new probe.
So that's it. If you measure the depth of the thermowell before you purchase your temperature probe you can make sure that the sensor will be compatible and the temperature reading will be accurate.
Thank you for watching. If you want more information you can find it at nowicksensors.com or brew-data.com.
21 июн 2015
