Platinum Resistance Element

[pgm]

Hi all

I am back after a long time nothing has changed here. Hope everyone is doing good.

I have come across some Platinum Resistance Elements. I have some pics to show you and maybe someone can shed some light for me what the spec should be. Pt100 pt500 pt1000

I have done some research and these item have been produced by bush beach engineering ltd. some of the probes are very long 4.6meters.

Might even get out the lab equipment and do a test run.

 

[Platdigger]

Before you do any test runs, these should be worth more than there pt scrap value.
Assuming serviceability of course.

 

[pgm]

very true but i am having trouble sourcing the correct person who would buy these

if you know anyone who wants them let me know..i have a few

 

[Lou]

The platinum isn't the whole way through. These are Pt100 temperature probes.

 

[pgm]

The platinum isn't the whole way through. These are Pt100 temperature probes.

I might open one up and have a look at the insides.

Will document with pics and upload them. This should help anyone who finds them with no label

 

[pgm]

Ok opened one up today

this was 3.67 meters long

do not know what the white powder is

the wire is in the white wire 4 wires are in it

I hope LOU or anyone else can help explain more about this probe

here are the pics

 

[butcher]

The white sand is most likely just silica sand.

If these are temperature probes thermocouples, they normally work on the principle where two dissimilar metals are joined together they will generate a small current when heated (a few milliamps of current), many different types of metals can be twisted together at on end (two dissimilar metals) and will generate a current when heated with a flame, some metals (and combinations of two dissimilar metals work better for this effect). if that is what these are, if they are Platinum I would suspect it to be one of those metals, it may not be part of the lead wire, but would be one of the metal wires where the two dissimilar metals meet either twisted together or welded wit a small bead at the end of the junction.

I would not expect the can on the end of a thermocouple, although some can have them.

http://en.wikipedia.org/wiki/Thermocouple

 

[Lou]

Those are likely resistance thermometers. They are not as valuable on a scrap basis as thermocouple wire, which often has large runs (like what is used in big probes in glass manufacturing) of Pt and Pt/Rh alloy joined at a welded bead junction.

There are several types of resistance thermometers.

I refer you to:

http://en.wikipedia.org/wiki/Resistance_thermometer

I use similar probes for the temperature measurement in our hydrolysis reactors while refining, humorously enough, platinum. They are pretty darn accurate.

 

[pgm]

Thank you to butcher and LOU for your help.

I will now take the wire from the one probe i am doing the test and weight the total wire and do an XRF on it.

Will add more pictures this should help others who come across these probes.

 

[butcher]

RTD (resistance temperature detector)
That makes more sense, than the thermocouple, that would explain the can case.

 

[pgm]

Thanks butcher for the diagram

I have seen this but was trying to work out the pt content in terms of weight and a break down of the rest of the elements in the tube.

will update soon on the content

 

[anarxi]

I'll bring up the topic.platinum thermometers from the Soviet era.
however, physics has not changed since then.
the element itself is the finest platinum wire.findings from a glass capsule, platinum-rhodium alloy 30%.
The dark parts are where the copper wire is soldered.
after dissolution in nitric acid
only platinum and rhodium will remain......

 

[anarxi]

Sorry, I was a little misleading.These sensors contain platinum-iridium 10 alloy.This is what the spectrometer showed.

 

[anarxi]

platinum-rhodium 30% in such sensors

 

[hoytSmith]

Definitely worth more as an rtd, even if it takes you a few years to find a buyer. Weigh the pm wire after you dissolve the solder (assuming that’s the join method) — rtd’s are very, very fine so as to be resistive to small currents. If you refine, or even just recover and sell them, you’ll likely pay yourself very little for your time & effort in the end.

RTD’s are expensive because they're precise and less prone to externalities (induced currents in conductors) and calibration drift than thermocouples. They’re not used at refractory temperatures, they mostly have application in chemical processing.

 

[anarxi]

Definitely worth more as an rtd, even if it takes you a few years to find a buyer. Weigh the pm wire after you dissolve the solder (assuming that’s the join method) — rtd’s are very, very fine so as to be resistive to small currents. If you refine, or even just recover and sell them, you’ll likely pay yourself very little for your time & effort in the end.

RTD’s are expensive because they're precise and less prone to externalities (induced currents in conductors) and calibration drift than thermocouples. They’re not used at refractory temperatures, they mostly have application in chemical processing.

Thank you, I understand that as a product they are much more expensive.

but most likely these glass caps (there are about 150 of them) are not thermometers.
Most likely this is part of some kind of catalysis installation or other chemical process.
I assume that the installation itself was dismantled long ago and the person who knew what it was took them for himself.
then he died, and his legacy, not knowing what it was, was put up for sale at a flea market.
A very common story.

 

[anarxi]

Yes, it's still a resistance thermometer.
At an ambient temperature of about 15 degrees, the resistance shows 20 Ohms.

If you heat the sensor with an electric hair dryer, the resistance increases very smoothly.