In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.
Subject: TC gauge ranges
Date: Dec 13, 9:19 am
Poster: Richard Hull
On Dec 13, 9:19 am, Richard Hull wrote:
Check out the 1999 duniway catalog page #40 and you will see the two analog gauges. They have succeeded is mis-labeling the top image "TCG-531/2NT" It is actually "TCG06M/2-NT"
Notice the mid scale is about 50 microns and the 10 micron point has plenty of room to the left before zero with easily discernable graduations. The 1518 is just a wee bit more expanded than this!
Compare this to the photo just below of the true TCG-MTR-531. The 10 is a scrunched up at the left end of the scale and mid range is in the 160 micron area!
We must not deceive ourselves though. No matter what tube we use, they are pretty hairy to calibrate at the low end as they are near the point where they total fail to work the thermocouple at all. They are accurate only for air and air alone! They would have to be recal'd for any other gas. Then they would not be good for air roughing any more. That's why I maintain several gauges with the cal marked on them. Thee plug into the same tube in most cases.
Those interested in details on how to make and cal your own TC gauge, and who aren't afraid of a little minor electronic work, should check out the Bell Jar website of Steve Hansen where an online article about this is avaialble.