/g/VacuumX

ionization gauges and vibration

mcguire@... (Dave McGuire) — Fri, 24 Jun 2022 10:23:40 -0700

I am putting things together piece by piece, and I'm noticing that the point where I've temporarily installed my ionization gauge tube has quite a bit of vibration from the roughing pump.

Am I correct in assuming that this would be bad for the tube?

Thanks,
-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA

Re: bolts/nuts for conflat flanges?

mcguire@... (Dave McGuire) — Tue, 21 Jun 2022 14:56:35 -0700

Perfect, thank you! Looks like the LDS folks sell kits of hardware too, very nice.

-Dave

Re: bolts/nuts for conflat flanges?

betwys1@... (Brian Whatcott) — Tue, 21 Jun 2022 12:32:39 -0700

This URL has some useful advice on conflat fixings:

Kurt J. Lesker Company

Vacuum Science Is Our Business

Brian W

On Tuesday, June 21, 2022, 12:15:56 PM CDT, Dave McGuire <mcguire@...> wrote:

Hi folks. Is there a standard, or at least a favorite, for the

bolt/nut sets for conflat flanges?

Thanks,

-Dave

Dave McGuire, AK4HZ

New Kensington, PA

bolts/nuts for conflat flanges?

mcguire@... (Dave McGuire) — Tue, 21 Jun 2022 10:16:04 -0700

Hi folks. Is there a standard, or at least a favorite, for the bolt/nut sets for conflat flanges?

Thanks,
-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA

Re: vacuum chamber advice

nickjandrews@... (Nick Andrews) — Fri, 17 Jun 2022 22:19:28 -0700

That's pretty much what I thought. But it came with a Hastings tube and at least one high quality valve, either of which is worth more than I paid for the whole thing.

Re: vacuum chamber advice

johnd@... (John Doran) — Fri, 17 Jun 2022 18:08:16 -0700

Nick,

The sorption pump exploits the ability of certain materials to capture and hold large volumes of gas when taken down to liquid nitrogen temperatures. You hook it up to your system (depending on the size of the system, you may need more than one “pump!�� and immerse it in the LN bath. You “empty�� it again by allowing it to return to room temperature, venting the gas out another valve.

It’s a roughing pump, believe it or not!

It has traditionally been used in environments where absolutely no hydrocarbon contamination can be tolerated. I can’t imagine it would make sense for any amateur-built system (LN is megaspensive, and you need lots of it)��

-John

Re: ionization gauge fittings

mcguire@... (Dave McGuire) — Fri, 17 Jun 2022 16:09:44 -0700

Perfect! I was unaware of these types of fittings. This clears up a lot. I'll be placing an order with the LDS folks soon. Thanks for the tips!

-Dave

Re: vacuum chamber advice

nickjandrews@... (Nick Andrews) — Fri, 17 Jun 2022 15:18:13 -0700

I also acquired a Huntington Cryo Sorption pump really cheap. Not sure how they work or if it even works. Need to research it...

On Thu, Jun 16, 2022 at 7:15 PM Dave McGuire <mcguire@...> wrote:

On 6/16/22 11:18, Nick Andrews wrote:
> Hello Dave, funny you mention this... I finally got my cart (old
> Beckman ultracentrifuge over to TX from NM. Yeah, it's still on the
> trailer, but I have to clean it off to haul back there at the mighty 4th
> to try and finish my move to San Antonio and sell the house (it's only
> been since Aug 2017 that I started moving).

Ugh, moving sucks!

I've long said I'd rather be shot than move. Misery and woe. We hates it forever! This one is worse, with 11 years of accumulation, 8 of which was with ready access to a lot of construction demo and university auction winnings. I moved at least five tons of structural steel here, lathe, milling machine, two dental xray machines, a powder diffraction xray, so, so much high voltage stuff, lasers, boxes and boxes and boxes of books and magazines, Geiger counters and radiation detection stuff. Not quite like the end scene of Raiders, but I could easily solidly pack a 20' cube.

> Super heavy duty cart.
> Even after I removed the reefer unit and drive motor assembly (bearing
> had failed and leaked oil all over), roughing pump, diff pump, control
> panel/top, top sliding door plate assembly, electronics, the thing still
> weighs over 400#. I think I am going to try to block off the hole in
> the bottom of the chamber and reassemble it to use as a vacuum chamber.
> The outer ring has a Hastings type TC gauge in it already. Probably
> don't need the 1.5" thick explosion shield ring that sits inside that
> but until I need it for something else I think it will be just fine
> where it sits now. I plan to reinstall the Welch Duo-Seal (1 of 3 I
> have) as the roughing pump or use the Edwards RV one I have, and then
> use a small turbo setup I picked up off ebay (if it works). Have a
> couple of MKS Loadlock pressure sensors for the system, and a few KF25
> valves.

Very interesting; I don't know much about centrifuges. They're
mostly used for medical stuff, which I don't get into. So these big
ones have vacuum systems in them?? I wasn't aware of that.

These type are used in lab work all over. An ultracentrifuge can spin at over 100,000rpm and several people have died from rotor explosions at universities. Part of why it has that massive steel ring, to contain the shrapnel. There is a cooling coil around the white inner tub that the refrigeration unit circulated and cooled. The vacuum is to remove air resistance and decrease heat buildup. Pretty crazy, right?

> I bought (I think) a nice TC gauge with a bunch of tubes at auction from
> Bentley's in Albuquerque along with a ~30L dewar, about fifty 5C collets
> and around 50 slitting saws. A friend picked them up for me and I plan
> to drive up there from Las Cruces week of the 4th to pick it all up.

Nice! Take pics!

I will, assuming he bid on the right lot for me! It was cheap if not. Hope the dewar is good, as I need it to transport LN2 to the house to cool my HPGE detector.

> Diff pump was assembled to the housing with a flange and o-ring with
> thumb screws which I will need to adapt to the ISO63 (?) flange on the
> turbo. Was looking at a cross that is ISO/KF63 straight through and a
> couple of KF25 on the side. But there is no window in the top plate,
> which I'd like to have but might interfere with being able to use the
> slide mechanism to open and close it (assuming I am able to reassemble
> what I took apart before).

Have you seen the pricing on diffusion pump oil lately? Ugh. :-(

No, and I probably don't want to! Aiming to use the little turbo if it all works, but I do have 2 or 3 diff pumps. I'd like to try building a LN2 generator at some point...

> I mostly want a system to pump down tubes for lasers, neon and maybe in
> some crazy time try my hand at vac tubes or nixies. And eventually
> maybe a fusor. Still need to test the newer mill, Bridgeport 2J2 but I
> now have a horizontal attachment for it.

Sounds somewhat similar to what I want to do.

I'll at least have the equipment for it. Whether I actually get there or not will remain to be seen.

> What I've been advised is to go with KF type fittings using centering
> rings and o-rings instead of conflat, as they are reusable versus the
> conflat copper washers.

The single-use washers do seem like a pain, but they're not THAT
expensive if you aren't changing things around a lot.

Famous last words...

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA

Re: ionization gauge fittings

johnd@... (John Doran) — Thu, 16 Jun 2022 20:49:42 -0700

Dave,

Follow-up. Yes, these adapters will work with tubing sizes ranging from 1/16 inch to 1 1/8 inch (not the same part, obviously!).

You could use one to hook up your laser tube.

-John

Re: ionization gauge fittings

johnd@... (John Doran) — Thu, 16 Jun 2022 20:45:31 -0700

Dave,

LDS Vacuum (a relatively inexpensive outfit!) has a big selection of KF to "quick coupling" adapters. A KF25 to 1-inch quick coupling compression adapter is their NW25-Q100. $71.

-John

https://www.ldsvacuumshopper.com/nwtoquiccoup1.html

Nick's potential vacuum station starting point

nickjandrews@... (Nick Andrews) — Thu, 16 Jun 2022 19:59:25 -0700

There's also a bucket with the other bolts, some serious steel bars, other fasteners and odds and ends, and the 1/2" thick steel top door plate that used to slide to the side to access the rotor and such. The electronics mount to inside the front doors at the bottom. The Welch 1402 slides on some rails at the bottom. Like I said, it's... dirty... from sitting outside in the NM sun for the last 7 or 8 years.

Re: ionization gauge fittings

nickjandrews@... (Nick Andrews) — Thu, 16 Jun 2022 19:54:15 -0700

Oof...

Re: vacuum chamber advice

mcguire@... (Dave McGuire) — Thu, 16 Jun 2022 18:26:47 -0700

On 6/16/22 13:44, eosraptor1 wrote:

I think I like that one better. you can always use a camera inside to see what is going on if you dont have a view port handy. I run 3 USB cameras in my warp drive test chamber.

That's a damn fine idea!

8" UHV plates will be pricy even used on EBAY. Let me look to see if I can spare one for you.

Ok I'm definitely looking for those now; I got that other chamber. (the simpler one) If you can find them, let me know what you want for them. I'm gettin' excited over here! :-)

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA

Re: ionization gauge fittings

mcguire@... (Dave McGuire) — Thu, 16 Jun 2022 18:16:10 -0700

On 6/16/22 21:10, eosraptor1 wrote:

My suggestion is take a big gulp of air and get your checkbook out and buy this :
Leskers 1.00 EA SKU0323572 cost $ 1,700.00 USD
KJLC392-CF-US
KJLC 392 PACKAGE WITH DN35CF-DN40CF FLANGES,
INCLUDING KJLC 392, 2X CONVECTION GAUGES, 10 FT.
INTERCONNECTOR CABLES, AND US POWER SUPPLY
This works. It will tell you exactly what your chamber pressure is and exactly what your backing pressure is. You should not turn your turbo on till your chamber pressure is below 2 or 3 torr ( I dont turn mine on till below 1 torr ) and you need a backing pump that can get down to 10 millitorr or better.

I'm right there with you on that. But what I've got my hands on is a molecular drag pump, not quite as fancy but a lot more forgiving. I'm trying to make use of what I have, rather than buy all new.

Doing it that way is a lot more hassle, especially for me being a bit new at vacuum work, but the financial limitations here are severe. My business has been all but destroyed by the supply chain shortages; I'm sitting on orders here that I cannot fill until next year.

I know it is expensive but Leskers stuff is tough and it stays working.

Ahh, yeah. It's not an unwillingness to spend the money, it's the lack of existence of the money. ;)

Don't feel that I don't appreciate your suggestion; I honestly do.

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA

Re: ionization gauge fittings

eosraptor@... (eosraptor1) — Thu, 16 Jun 2022 18:11:32 -0700

Dave,

I dont know what that thing is.

My suggestion is take a big gulp of air and get your checkbook out and buy this :

Leskers 1.00 EA SKU0323572 cost $ 1,700.00 USD

KJLC392-CF-US
KJLC 392 PACKAGE WITH DN35CF-DN40CF FLANGES,
INCLUDING KJLC 392, 2X CONVECTION GAUGES, 10 FT.
INTERCONNECTOR CABLES, AND US POWER SUPPLY

This works. It will tell you exactly what your chamber pressure is and exactly what your backing pressure is. You should not turn your turbo on till your chamber pressure is below 2 or 3 torr ( I dont turn mine on till below 1 torr ) and you need a backing pump that can get down to 10 millitorr or better.

I know it is expensive but Leskers stuff is tough and it stays working.

Drew

Re: ionization gauge fittings

mcguire@... (Dave McGuire) — Thu, 16 Jun 2022 17:24:45 -0700

Ahhhhh, I see, thank you for the explanation. So if I wanted to connect such a gauge to a port that has a KF flange, there would be an adapter with a KF flange on one end and one of these compression fittings on the other?

Separately, I am hoping to do some evacuation of glassware, etc using this system eventually; are these types of compression fittings what I'd use for that as well, to temporarily connect glass tubing, evacuate, and then seal off?

Thanks,
-Dave

Re: vacuum chamber advice

mcguire@... (Dave McGuire) — Thu, 16 Jun 2022 17:15:35 -0700

On 6/16/22 11:18, Nick Andrews wrote:

Hello Dave, funny you mention this... I finally got my cart (old Beckman ultracentrifuge over to TX from NM. Yeah, it's still on the trailer, but I have to clean it off to haul back there at the mighty 4th to try and finish my move to San Antonio and sell the house (it's only been since Aug 2017 that I started moving).

Ugh, moving sucks!

Super heavy duty cart. Even after I removed the reefer unit and drive motor assembly (bearing had failed and leaked oil all over), roughing pump, diff pump, control panel/top, top sliding door plate assembly, electronics, the thing still weighs over 400#. I think I am going to try to block off the hole in the bottom of the chamber and reassemble it to use as a vacuum chamber. The outer ring has a Hastings type TC gauge in it already. Probably don't need the 1.5" thick explosion shield ring that sits inside that but until I need it for something else I think it will be just fine where it sits now. I plan to reinstall the Welch Duo-Seal (1 of 3 I have) as the roughing pump or use the Edwards RV one I have, and then use a small turbo setup I picked up off ebay (if it works). Have a couple of MKS Loadlock pressure sensors for the system, and a few KF25 valves.

Very interesting; I don't know much about centrifuges. They're mostly used for medical stuff, which I don't get into. So these big ones have vacuum systems in them?? I wasn't aware of that.

I bought (I think) a nice TC gauge with a bunch of tubes at auction from Bentley's in Albuquerque along with a ~30L dewar, about fifty 5C collets and around 50 slitting saws. A friend picked them up for me and I plan to drive up there from Las Cruces week of the 4th to pick it all up.

Nice! Take pics!

Diff pump was assembled to the housing with a flange and o-ring with thumb screws which I will need to adapt to the ISO63 (?) flange on the turbo. Was looking at a cross that is ISO/KF63 straight through and a couple of KF25 on the side. But there is no window in the top plate, which I'd like to have but might interfere with being able to use the slide mechanism to open and close it (assuming I am able to reassemble what I took apart before).

Have you seen the pricing on diffusion pump oil lately? Ugh. :-(

I mostly want a system to pump down tubes for lasers, neon and maybe in some crazy time try my hand at vac tubes or nixies. And eventually maybe a fusor. Still need to test the newer mill, Bridgeport 2J2 but I now have a horizontal attachment for it.

Sounds somewhat similar to what I want to do.

What I've been advised is to go with KF type fittings using centering rings and o-rings instead of conflat, as they are reusable versus the conflat copper washers.

The single-use washers do seem like a pain, but they're not THAT expensive if you aren't changing things around a lot.

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA

Re: ionization gauge fittings

johnd@... (John Doran) — Thu, 16 Jun 2022 14:57:23 -0700

Dave,

There are compression fittings that tighten onto the metal (or glass) sidearm tube and seal it with an O-ring; an example is the Kurt Lesker B-110-K but *everybody* makes them, including versions that have flanges on the other end for joining the adapter to the system.

The tube on your ion gauge is made of Kovar so that it may be soldered directly, if desired.

-John

ionization gauge fittings

mcguire@... (Dave McGuire) — Thu, 16 Jun 2022 14:35:30 -0700

Ok, more dumb questions. :) I have a new ionization gauge tube here that I would like to use, if possible, in the system I am constructing. Its connection is a metal tube around 1" in diameter. I see many on the market like this, and many with just glass.

How are these generally connected to systems, is there a type of fitting that somehow attaches to that metal tube?

Thanks,
-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA

Re: vacuum chamber advice

eosraptor@... (eosraptor1) — Thu, 16 Jun 2022 10:45:24 -0700

I think I like that one better. you can always use a camera inside to see what is going on if you dont have a view port handy. I run 3 USB cameras in my warp drive test chamber. 8" UHV plates will be pricy even used on EBAY. Let me look to see if I can spare one for you.

I would mount the turbo pump vertically on top and you can rough pump the chamber right thru the turbo and when it is low enough use the same roughing pump as the backing pump for the turbo.

Drew