TG-550 TC vac gauge tube

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Rex Allers
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TG-550 TC vac gauge tube

Post by Rex Allers » Mon May 11, 2015 6:21 am

I recently acquired a bunch of surplus parts. Among them is a vacuum thermocouple tube, Anelva TG-550. This stuff is probably circa 1990.

I looked for data and found this page with just basic info for the current TG-550C version:
https://www.canon-anelva.co.jp/english/ ... ail16.html

If I translate from Pa right, it should be for about 1x10-3 to 1.5 Torr. But there is no helpful information that I could find, like which pins are for what, heater current, or V to pressure output.

It looks like most common TC tubes with an octal base but it only has 4 pins: 1,3,5,7. I measured it with an ohm meter and between any two pins I see around 200 ohms, so the 4 all seem to be connected.

Does anyone know of a more useful set of specs or data for these things? I'd like to try to use it but it is hard to guess how to make a meter for it without better info.
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Richard Hull
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Re: TG-550 TC vac gauge tube

Post by Richard Hull » Mon May 11, 2015 5:02 pm

There were a number of spec's posted in a 1990's article in the Bell Jar for many tubes. The pins are probably common to many other TC gauge tubes.

Call Duniway or Lesker and ask to speak to their technical dept. They may be able to cross that number it to a common tube.

Richard Hull
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Re: TG-550 TC vac gauge tube

Post by Richard Hester » Tue May 12, 2015 3:36 am

Unless this tube crosses to something as simple-minded as a Hastings DV-6, I wouldn't bother. The Anelva controller that interfaces to this tube looks pricey., and nothing is decipherable as to the actual range of the tube, as the controller/gauge uses an LED bargraph display. It may clone to something as awful as a Varian 531 (or worse).
The Hastings DV-6 tube is the most commonly cloned in existence. These with associated controllers are widely available, and have the low-end resolution that makes fusor work easier.
If you can't find an appropriate cross, put the tube on Ebay, and use the funds to get something more common.

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Re: TG-550 TC vac gauge tube

Post by Rex Allers » Tue May 12, 2015 10:12 am

Thanks for the replies. I do have a copy of a Bell Jar article that gives some details on DV-6M, 531 and 6343. Good info and helpful overview. I also have a Teledyne Hastings table that gives pins, heater current and general parameters for 7 of their tubes.

Maybe the phone calls are a good idea.

In reply to Richard Hester:

Wow, pretty negative on this TC sensor.

I've been slowly accumulating parts for years. Eventually I hope to build a fusor but I'm not in a rush. So far little steps with wide inactive times. Too many projects.

I do already have other sensors that I can use. I just like to try and find a way to use things that fall into my lap. In this general class of vacuum sensing device, I have three MKS HPS 325 Moducell Pirani sensors. I'll probably use one of those for basic roughing vacuum, though the output is not very linear. Ways around that with a micro, I think. I also have a couple better sensors for the real fusor action-level measurements.

Now back to the TG-550... As I said in the original post, from the link page, this one is supposed to be for 10-1 to 200 Pa or (my math) 1x10-3 to 1.5 Torr, so I would think that is, "decipherable as to the actual range of the tube". I have no plans to buy a meter that was made to go with it. The technology to put some current in and measure voltage out is not daunting. I was hoping someone might have some details to save me experiments that may start with bad assumptions or fail.

I do have a Varian 531 too. Looking into the vacuum tube end they look very similar. Two perpendicular crossed wires that look to be welded at the intersection. I'd guess the wires are different materials, making the weld spot form the thermocouple action. I'll assume they may be similar in parameters and do some experiments as I find time. If I learn anything I'll post the results. (Not that many people are likely to have one of these TG-550's but maybe I'll let someone else have this one if I get any useful results.)

You don't seem to like the Varian 531. I tried to search on 531 in the group but the search function found nothing. Apparently '531' is not long enough or "lettery" enough to be an indexed word. It is a limitation we have to live with. Hence, can you share what characteristics make the 531 so "awful"? I'm not being facetious; why is the DV-6 better than the 531?
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Rich Feldman
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Re: TG-550 TC vac gauge tube

Post by Rich Feldman » Tue May 12, 2015 5:23 pm

Hi Rex. I work in San Jose (until retirement, management willing) and also have some vac. gauges to get running. Please check your Private Messages.
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Richard Hull
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Re: TG-550 TC vac gauge tube

Post by Richard Hull » Wed May 13, 2015 5:07 am

DV-6M is a universal tube and I have several TC gauges that use them. My favorite is the 1518 at about the same price. Its lower range is only slightly better expanded than the DV-6. A single 1.5 volt D cell battery and pot are all that is needed to set the tube up, but the meter and its scale are critical....As are all TC gauge meters. The bell jar article deals with these issues.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
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Re: TG-550 TC vac gauge tube

Post by Richard Hester » Wed May 13, 2015 6:35 am

There was a discussion of fusor - applicable thermocouple gauge tubes way back in the early years of the forum (maybe even as far back as the first "songs" site).
There are basically three thermocouple vacuum gauge tube types that are maximally useful for our efforts here in that they have extended resolution at the low end of the scale, where people here will do their most productive work. These are the afore-mentioned Hastings DV-6 and its many clones (and the easiest of the three to find tubes/gauge heads), the Hastings DV-5 (even more expanded low range), and as mentioned by Mr. Hull, the 1518 tube, sort of a dark horse in that gauge tubes and (especially) meters are not as readily available ( Duniway, Lesker, and LDS Vacuum, among others, sell clones of this tube). You can get the DV-6 or a direct equivalent from pretty much anyone that sells vacuum gear. Used DV-6 gauges are not hard to find on E-pay for a wide range of prices.

The attached link takes you to a pdf data sheet that shows the meter faces of the gauge heads for the DV-6 and DV-5 so that you can see their range of emphasis at the low end of the scale.

http://www.teledyne-hi.com/pdfs/PB-105_ ... -Tubes.pdf

The Varian 531 can be used for fusor applications, but it is less desirable in that its low end scale is bunched up, so there is not a whole lot of resolution. The link below shows a meter face for a 531-based gauge next to one for a DV-6

https://www.duniway.com/images/_pg/manu ... 31-06M.pdf

There are lots of other gauge tubes out there that have very limited utility for us here, in that they show little to no resolution for the 0-20 micron range. Some of them zero out way before our region of interest. These tube/gauges are useful for refrigeration, freeze-drying, resin/oil degassing, etc., but not for fusor work. Do your homework, lest you get saddled with a clunker.

Keep in mind that thermocouple gauges are not all that accurate, and are used for "indication" purposes rather than precise measurements. For more accurate measurements, Convectron gauges are better, and capacitance manometers are the "gold" standard. Keep in mind also that the price goes up with the level of accuracy, and things can get really expensive unless you happen to make a lucky score. A thermocouple gauge is a good starting point, and won't drain your pockets if you shop wisely.

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Re: TG-550 TC vac gauge tube

Post by Richard Hester » Wed May 13, 2015 7:01 am

Here is a picture of a 1518-based gauge (too expensive by far), showing its scale - pretty good.
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1518_gauge.jpg

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Rich Feldman
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Re: TG-550 TC vac gauge tube

Post by Rich Feldman » Wed May 13, 2015 10:03 am

rexa wrote: ... I have three MKS HPS 325 Moducell Pirani sensors. I'll probably use one of those for basic roughing vacuum, though the output is not very linear. Ways around that with a micro, I think. ...
Here's another way people have found a way around that, when standard nonlinear voltage response is tabulated in a manual.
This example is for Mini Convectron 275. The scale is hugely expanded above 1 torr (that's the point of convectrons) but pretty cramped below 10 microns. Richard H's picture links just taught me that DV-6's have better resolution down there.
DSCN1042.JPG
That computer-drawn scale card was discussed here 4 1/2 years ago. The OP uses an outside link, now broken, in place of one image. viewtopic.php?f=10&t=4047&p=21455
All models are wrong; some models are useful. -- George Box

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Richard Hull
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Re: TG-550 TC vac gauge tube

Post by Richard Hull » Wed May 13, 2015 5:44 pm

The 1518 gauge tube is only $55.00 list price from Lesker. Crafting a meter and scale for it might be worth a hack. That expanded lower end might be worth the effort. The typical meter is a 9 or 10 millivolt meter. I think the current set on the heater is on the order of 15ma, far less than the DV-6M.

Remember it only needs one 1.5 volt D cell a pot and a meter and you have a gauge. It should be remembered that it is the tube and not the meter that has the expanded lower end reporting expansion.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

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