Recent content by timsch

3rd party inspection service has done the measurements.

We will test it to 1.5 times its MAOP. I will keep your other recommendations in mind. Thanks for the responses - much appreciated.

We're taking 4 measurements @ 90deg every 3 feet, totaling 168 points (chambers are actually over 100' long). Statistically, I think we should be fairly confident that we have a pretty good picture, but I agree that we likely don't have the absolute minimum thickness. My calculations are...

Thanks for the response. We're measuring from the outside.

I'm running calculations to re-rate our carbon steel hydrotest chambers. I have UT wall thickness measurements. These chambers are very long (4 to 5" pipe, 100' long), so any scale that might be on the ID of the chambers was not removed. Would scale throw off the measurements, or would the...

For high calibration temperatures, the reading is low, for low calibration temperatures, the reading is high. The further from ambient temperature, the greater the deviation, which supports the thermal conduction along the wire hypothesis. Moisture in the MgO is always on our minds...

I agree. That's been my hypothesis. We had issues calibrating at -196C, being off by 5-8C when 1' of wire was immersed. When we immersed the majority of the wire, we were much closer. The further from ambient we've been, the greater the error, and the error has been to the ambient side of...

3-wire with a PT100 wire-wound ceramic element

We use Class A resistors by default in our applications. With our typical 22-26ga extension wire, we rarely have problems meeting class A tolerances and never fall outside class B, with this wire we are having difficulty with class A half the time and are even falling outside of class B...

Does anyone have experience with RTD elements that use heavier gauge extension wire than that which is typically used? I have an application where customer has specified 18 gauge wire where our standard is 22-26 gauge wire. We are having more difficulty with calibration than we typically do...

Thank you everyone for the input. It's been a good education for me, and is much appreciated.

I accidentally hit like when I meant to hit reply. I actually don't like it. While it may be true looking at it from a bean counter perspective, it is a learning opportunity for an engineer. It's been a good use of my time learning about a discipline I had no experience with that hopefully...

Ours is an R&D facility. This is a full scale furnace as used in refineries. Roughly 10 x 8 x 15 ft^3 in the radiant section, which is where we've tapped through the roof for this particular test. The 1-1/2" pipe is part of a test piece only. I mentioned earlier that there is a slight...

I was not looking at the curve correctly. Now I understand that the no-flow condition is at a dead-head condition, and maximum flow at roughly ambient happens because there is no resistance to the flow. Thank you. Yes, this curve is not quite accurate for our conditions. From the...

I apologize if I've misled anyone with wrong terminology. After seeing the drawing, does that change anything with the calculations you've given?