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Old 06-09-2018, 10:45 AM
Chip Chester Chip Chester is offline
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Trash or treasure?

Found the item below in the weeds while cleaning up back lot at ETF.
Looks like a cam for a timer switch, or maybe an emoji stencil. Or perhaps I've found Nemo.
It was in the area where CRT ovens were scrapped out (by others).
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Old 06-09-2018, 06:42 PM
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MadMan MadMan is offline
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It looks about 3 inch in diameter, that right? Looks like a miniature painter's palette. Possibly an electrical insulator for something. Is it flimsy or solid?
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Old 06-09-2018, 07:05 PM
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Celt Celt is offline
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It's a ghost of Pac Man...

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Old 06-09-2018, 09:51 PM
Chip Chester Chip Chester is offline
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5.5" at widest point; approx. 1/16" plexi. 1/2" hole. Stiff, not flimsy.
Celt, you may be close, but it doesn't make any 'wocka-wocka' sounds. At least not yet.
I'd be happy to put it back inside the warehouse, but I'll wait until someone chooses a specific destination, so it doesn't get lost.
That destination could well be the dumpster, of course...
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Old 06-12-2018, 10:49 PM
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ohohyodafarted ohohyodafarted is offline
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The item you are looking at is the special cam that was used in the controller for processing the long 6 hour pump down for 15GP22 crt's. It goes in the Partlow chart recorder temperature controller timer that controlled Hawkeye's oven temperature ramp up and cool down cycle.

The Partlow ramp controller has a clock timer that does 1 revolution per 3 hours. The cam rotates with a cam follower on the edge of the cam. AS the cam follower rides further and further away from the center of the cam, the temperature increases. At the 3 hour mark, the cam is removed and flipped over, and the cycle reverses. The second 3 hour period eventually goes into a cool down period toward the end of the cycle.

The Partlow ramp controller had a temperature sensing element consisting of a long stainless steel tube with a metal reservoir bulb at the end which sat inside the oven to sense the actual temperature. The stainles steel bulb and the tubing were filled with mercury. The end of the temperature sensor that was connected to the bottom of the Partlow ramp controller had a piston inside it. AS the temperature increased in the oven, the mercury expanded which pushed against the piston in the end connected to the Partlow controller. The moving piston pushed against a mechanism that compared the position of the cam follower, to the temperature that was being sensed by the mercury element. If the cam follower said we should be at 300 degrees and the sensor detected only 290 degrees, the Partlow controller would trip a micro switch which energized the gas valve and the gas burners would ignite. Similarly when the temperature was higher than the cam follower wanted, the micro switch would open and the burners would extinguish.

By plotting the ramp of the cam, you could control the rise and fall of the temperature of the oven as fast or slow as you wanted. IN addition there was a circular chart recorder in the Partlow ramp controller that actually had a pen that tracked the actual course of the temperature over the 3 hour period.

It was old school, but it is what we had back in the day and it worked very well. Sad to here that the Hawkey oven has been scrapped. There was a lot of good usable (although old) technology in that oven. I hope at least the usable components were saved.

This photo shows the Partlow processing controller with one of the plastic cams installed.
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Last edited by ohohyodafarted; 06-20-2018 at 11:52 PM.
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