Kaye 140-4 Ice Point Reference

[beanflying]

Not so much as a teardown but a post sludge removal reassembly and hopefully powering up. Part of the use of these Calibrators is the wells are partially filled with mineral oil and the users appear to have used a bucket to slop it all over the unit and missed the wells. Sludge removal was about 500ml of Sugar Soap, brushes and cloths for a few hours.

These devices have one purpose and one set point only 0 degrees C or nothing. Stability of 0.01C typical, Guaranteed 0.025C. A triple point Cell would be more accurate but I have no wish to carry the other bits to make it work.

https://www.kayeinstruments.com/en/thermocouple-references/kaye-ice-point-references/k140#specifications

Manual https://www.scribd.com/document/344032113/Kaye-K140-K150-K170-Ice-Point-Op-Manual

This one is a US 115V and I was hoping for a simple conversion to 240V with maybe a new fan but at this stage no luck. Not the end of the world I already have a transformer up to the job but it would have been better long term.

The main block is interesting and if anyone knows what is inside it let me know? My best guess is it is water filled and works on the expansion of Ice to push out the piston shown into the switch and turn off the Peltier Cooler? Very simple with screws to adjust the degree of expansion needed to trip the switch. The screws are accessible from outside the case and remnants of Cal stickers are visible that would have covered them.

It arrived with a couple of missing feet and a smashed fuse holder so as of yet not powered it up. Tomorrow job. The main control block seems to be filled with pitch or epoxy and is in a soldered box 

[Kean]

Very interesting.  Have been thinking of building something similar to this, but obviously not with that level of accuracy in mind.

[beanflying]

Very interesting.  Have been thinking of building something similar to this, but obviously not with that level of accuracy in mind.

I have been playing around with the design for a homebrew bath and peltier design, Based on a twin walled Bento Box and a few of these Booze Flasks for wells. Still a figment of my imagination in spite of having all the bits to get going on it. Anyone got 'spare time' 

Basic plan is a bath with mineral oil and heater/cooler/pump, tubes filled with mineral oil or dry as needed but isolated from the bath. Aiming for -20-30C and up to 50C+ (possible additional non peltier elements for this). This combined with my Sika 18600E and now this Zero Point is more or less my Temperature Cal gear sorted.

https://www.aliexpress.com/item/Portable-3-Layer-Double-Layer-Stainless-Steel-Thermal-Lunch-Boxs-Thermal-Bento-Box-Leak-Proof-Seal/32825032029.html?spm=a2g0s.9042311.0.0.27424c4dGhBJON

https://www.aliexpress.com/item/Creating-lifestyle-Grade-304-Stainless-Steel-Hip-Flask-Like-Cigar-Long-Round-Bottom-Mirror-Polished/32806212172.html?spm=a2g0s.9042311.0.0.27424c4dPbhn2X

Back onto the toy at hand and it seems I have a winner. New Feet printed to replace the crumbled mess, new fuse holder. Plugged it into my transformer and took some 5 minute interval Temperatures. Seems it will be around 30 minutes to get to about zero and it seemed to have a slowly decaying hysteresis and was much more settled after another 30 minutes.

My Agilents are still stuck in between Keysights moving house and getting their Calibration done and I have a Fluke 5616 coming from HighVoltage later in the month so some accurate testing and recalibration if needed then.

Things of note the fan is NOISY and some sort of change may happen. Other than that it is boring and the $200 USD landed gamble paid off 

[beanflying]

So Keysight is 'partially' forgiven random unannounced freight delivered my 34401 and 34461A's back to their proper place late in the day. I have roughed into place the best current 4W RTD I have in stock and left the R₀ set at 100 Ohms. Seems it may be running a touch under but sitting nice and stable so next thing to do is wait for the Fluke Probe to travel from Germany.

The little Elitech in spite of it's price I know is within 0.1-0.2 @ 0C as a sanity check. The earlier spot check with the K type thermocouple and 121GW are well within the combined spec for both.

[beanflying]

Data from the last 16+ hours. Ambient was 14C when I started dropping to 3C and back up to just over 20C. Seems the Kaye is holding steady and I suspect the 34461A is the variable device. Worst Case it shows about +-0.005C for a 15 degree swing in ambient between them.

Some more data to come over the next month. First job recalibrate my two 34970 loggers and run a proper test with several RTD's. Ambient temps etc and the more accurate RTD in the DUT.

EDIT: Took the cover off to look at reducing the fan noise or getting another. Shot shows the piston from the block now in close contact with the switch for temperature setting.