Ratheon Liquid Time Tubes???
Added 2024-02-05 23:29:10 +0000 UTCDid they exist? Did anyone use them? Who knows? I certainly have no idea. But it's a cool topic...
Comments
In one of my previous lives, I repaired Tektronix oscilloscopes for a living and those would sometimes be fitted with an elapsed time indicator like this https://w140.com/tekwiki/wiki/Elapsed_time_meter
Gordo
2024-03-16 19:13:16 +0000 UTChttps://www.mavin.com/pdf/Curtis%20Coulometer.pdf
adrian
2024-02-06 21:43:20 +0000 UTCI've seen one from RS components. I might even still have it. There were both wire-ended and fuse-format versions, the fuse could be flipped around to measure the next session.
adrian
2024-02-06 21:43:16 +0000 UTCAs I recall, they were in theory reversible. But there were practical limitations. On being that once there was a bubble within the mercury in the capillary line part of the 'thread' of mercury became immobile. But the other problem, in the example of projection lamps, is that if you replace the lamp before the mercury had run all the way through, the reversal only gave an indication until the amount of time that the first lamp had been in use.
Michael F Barushok
2024-02-06 05:22:22 +0000 UTChttps://www.bulbamerica.com/products/ushio-uxr-mt-mercury-timer
Donald J Arndt
2024-02-06 04:53:15 +0000 UTCSeems to me I remember the mercury ones were reversible by running the current back through again by flipping it making it reusable.
Donald J Arndt
2024-02-06 04:49:46 +0000 UTCI used to see the little capillary tube hour meters on deuterium lamps for UV/Vis HPLC detectors, I always wondered if it was actually mercury because I'd have thought by the mid-90s people wouldn't be putting mercury in anything anymore but probably it was also a holdover from older designs. I guess it helped diagnose lamp problems by telling you that the lamp was super old so don't be surprised it died but I suppose the real reason for them was for warranty purposes, so they could tell you it had enough hours to be out of warranty! This tube might have been intended for that, just to indicate something had enough hours on it to be out of warranty.
Michaela Pereckas
2024-02-06 01:42:19 +0000 UTCIf I saw it at a trade show I'd ask the Raytheon rep "How do I know the time if it's all just subjective, slow color fading?" There were already electromechanical time totalizers available that were super-easy to read by the thousands on the outer scale and 100s on the inner scale. While far more expensive than a glass tube full of fading liquid, if time were critical, as on military and avionics, to replace parts at specific hours, this fading tube color doesn't make much sense. As Michael mentioned above, I too still see those mercury tube elapsed time indicators on various larger aircraft instruments. There's no way that I know of to reverse the mercury to make it reset or run backwards. The hermetically sealed mechanical Airpax time totalizers that I still see used in military and avionics equipment today cannot be rolled backwards either. They are useless after 9999 hours. But, interestingly enough, when I looked up the actual MIL specs on a 3 axis "8-ball" attitude director indicator, the useful life of the instrument was specified specifically at 5000 hours. But I've seen them with their built-in time totalizers going way past 7500 hours, so they either were built better than expected, or, more likely, were repaired long after their 5000 hour mark. One has to take into account the fragility of a glass tube full of liquid. I've seen curved mercury switches on gyros that help cage it to the correct orientation by just using gravity to center the mercury in the tube that had wire sensors built into the glass. I've seen some gyros where the tube of mercury fractured and literally made the whole gyro unusable. Mercury makes a mess when just splattered all over precision mechanical stuff as used in physically spinning gyros. Cool idea, though practicality seems questionable. Thanks for sharing the old ads. They're great historical documents!
Matt Wietlispach
2024-02-06 01:33:04 +0000 UTCI think you are on the right track. It's cumulative so maybe it tells you when you have used the entire capacity of a battery or other consumable?
Curtis Onstott
2024-02-06 01:23:34 +0000 UTCI’ve certainly seen the Hg capillary tubes in standard glass tube form factor- but something like that?! Crazy. Cool advert :)
Fred Niell
2024-02-06 01:21:55 +0000 UTCI've never seen that product other than in the old advertisement. I have seen a similar one that's liquid mercury in a capillary tube. Either seems likely to be irreversible and therefore would need to be replaced when reaching full scale. The likely uses would be in equipment that requires an overhaul after a certain number of hours and the replacement would be supplied as part an overhaul kit.
Michael F Barushok
2024-02-05 23:52:50 +0000 UTC
