Cleaning/Repairing Edwards E2M5

Every fusor and fusion system seems to need a vacuum. This area is for detailed discussion of vacuum systems, materials, gauging, etc. related to fusor or fusion research.
Chris Mullins
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Re: Cleaning/Repairing Edwards E2M5

Post by Chris Mullins » Fri Jan 04, 2019 1:03 am

A gauge that's been used by several here (I have two) is the MKS 901p, good from atmosphere down to 1E-5 Torr, with log analog output and serial interface. Here are a couple of discussions about it:

General discussion: viewtopic.php?f=10&t=11533

RS-232 interface board: viewtopic.php?f=10&t=11730

You can usually find them (used) on ebay for around $35-$45 with KF16 flange.

Bruce Meagher
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Re: Cleaning/Repairing Edwards E2M5

Post by Bruce Meagher » Mon Jan 07, 2019 8:32 pm

Ameen Aydan wrote:
Thu Jan 03, 2019 11:50 pm
... I still need to find a proper inlet valve for gauging. I can't find anything so far for a good price. I need it to be a KF flange which is the biggest problem. Any recommendations?
You could try <https://www.ebay.com/itm/292158415411> for $12.50 shipped. The image below is what I received. It doesn't have the proper lip for an o-ring seal, but those on a budget can make it work. How to get a proper seal with these large BSP threads without an o-ring is an exercise left to the reader.

Bruce
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MBSP_KF25.JPG

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Dennis P Brown
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Re: Cleaning/Repairing Edwards E2M5

Post by Dennis P Brown » Mon Jan 07, 2019 11:41 pm

On a mechanical pump, teflon tape will seal it very well. I've had success even with 10^-5 torr in my chamber but I don't recommend it generally for those high vac applications.

Ameen Aydan
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Re: Cleaning/Repairing Edwards E2M5

Post by Ameen Aydan » Tue Jan 08, 2019 12:04 am

Hello

Thank you all so much for your suggestions, I can't say enough thanks in a life time. I just took a look and will purchase it soon. Since I'm from Canada, the price of shipping is $16 dollars... So as soon as I get that all worked out I should be able to purchase it. I also purchased an MKS 901P. The seller says the product is already calibrated and works perfectly! I purchased it long before the previous update, just forgot to mention it. Oh, and It was sold to me for $35 but the shipping was (as to be expected) $15. I hate it but I have to live with it... Oh well. An update on my pump will be coming soon. I just have to finish some useless homework first.

Ameen Aydan

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Re: Cleaning/Repairing Edwards E2M5

Post by Ameen Aydan » Thu Feb 14, 2019 3:41 pm

Hi all,

I finally programmed my MKS 901P using python and got it reading pressures and stuff. I will detail the whole procedure later. I also finally got the necessary adaptors and clamps for testing so I got right to it.

Because the pics are really big in size i kept them in a separate google drive file. It's better to open them in a separate tab as I will be referring to them based on the number of the pic. I will use this system now and on. Here is the link to my results --> https://drive.google.com/drive/folders/ ... _cKYdHM7dh

So first I took out a little of the disgusting oil the was already in the pump (1). It was a viscous mess and I don't even know how beat this pump was.

Next, I put in about 3 quarters of FF into the pump and ran it for 6 hours total. Following that I decanted the oil and it was off colour but still had the original red colour. This clearly meant that something was being cleaning out! By now I hadn't gotten my gauge so I I couldn't do anything. 2 is the pic of the decanted oil.

Now, I added the little bit of FF I had so that the oil line was slightly above minimum. I was distracted with school and exams and the whole mess made me forget about it for month. I came back to it yesterday and I let the pump run for about 2 hours to let the oil warm up. The oil I decanted in pic 3 was very concerning. This was because of how dirty it was! I didn't expect it to look anything like that and so it was a complete surprise. This clearly meant that even though I used FF I should have left it for a bit longer! It also goes to show how frigin' dirty it is, and how much might be left.

So after that I out about a quarter of my normal vacuum oil into the pump, again, just above the minimum line, and let the run for 2 hours. It came out slightly less dirty than the FF I mentioned. Again, very concerning. Now I would also like to mention that even though I used a little bit of the oil, when I connected the gauge and I gave a good pump down, I reached 13 micron in about 3 minutes. It's not good but not bad either. So I tried doing it again, and again, and again. Every single time after that I only managed to get 10 Torr. I will put a video up soon, it'll be named 4.

OK so, I was pretty annoyed. So I just decanted the oil and added the rest of my bottle until there was enough oil that it was slightly bellow the max on the oil metre. I gave the same pump down and had everything connected properly. Again, I only achieved 10 Torr.

I'm still here and I don't know what to do. Here are my assumptions. I'm using the recommended teflon the Dennis told me about. I think that there is probably some really big leaking going on. I want to get the proper inlet but its too expensive. I might try welding a lip so I can get the proper o-ring seal. The second thing that I think is wrong is the gauge. When set to factory default the gauge reads 769 Torr at normal pressure. When I pumped it down and got to 13 microns, it displayed 740 Torr at normal pressure. So I set it back to factory default and got the 760 Torr again.

I put the gauge strait on the inlet so I think that when I pump down some of the pump oil got on the gauge and damaged the sensor. I wouldn't know if that's true because i'm not getting any red lights (indicate that the sensor is faulty). I know that when I swiped the inner part of the gauge it felt a bit oily, but I could never see any actual oil. Maybe it was just a placebo?!?

Anyways I have a lot more to show but I will leave it out for later. For now I just want to know if my pump is just garbage. I spent too much time and money on this so it would be disappointing to just throw it out. Is there anything wrong with my gauge? I don't know what steps to take at this point.

Ameen Aydan
Last edited by Ameen Aydan on Thu Feb 14, 2019 4:04 pm, edited 1 time in total.

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Dennis P Brown
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Re: Cleaning/Repairing Edwards E2M5

Post by Dennis P Brown » Thu Feb 14, 2019 4:00 pm

Sorry the pump is still making your oil so dirty. By the way, I can only see one pic when I open the link you included - a pic of your tools and teflon tape. Is there only that pic?

You cleaned the inside case but did you dis-assemble the actual pump stages? I did this with my pump and cleaned it. That made a huge difference. Consider the amount of dirt/corrosion in your case, the inside of the pump chamber is likely bad, too. Hopefully, none of the critical surfaces are damaged. That those areas are contaminated might explain your failure o get down to a few microns. Your pump oil should stay clean when running the pump so likely the internal mechanism does need cleaning as well.

Ameen Aydan
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Re: Cleaning/Repairing Edwards E2M5

Post by Ameen Aydan » Thu Feb 14, 2019 4:10 pm

Hello,

Thanks for your reply. I only cleaning the case and not the stages. Richard advised me not to do so until I tested the pump. I don't want to spend more money so i'm afraid of opening up the stages as that would require me to change the o-rings. I remember someone saying that the orings can only be used once...

I can do it but I think a confirmation would be better. I would also like to be 100% sure the gauge is not damaged. Do you think I should go ahead?

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Dennis P Brown
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Re: Cleaning/Repairing Edwards E2M5

Post by Dennis P Brown » Thu Feb 14, 2019 5:08 pm

Gauges can always mislead. So, confirming that it is accurate is very important.

As for my pump, the dis-assembly of the actual internal vacuum pump assembly was done without a kit. I did damage a flat gasket but silicon sealant fixed that. I reused the o-rings but that could be hit or miss - one did look really flat but I simply reused it (again, a little silicon sealant.) The pump works fine and gets me down to under 2 microns (guess I got lucky.)

I really did need to do it since I found issues with some internal parts that did need serious cleaning - springs, balls and some linking sections.

Doing this type of rebuild is a judgement call. I'd suggest first checking the gauge, of course.

Still, your oil is coming out dirty simply by normal operation and that is certainly an issue and will have to be addressed in all likelihood (and is costly to keep replacing.) Getting a rebuild kit might be worth the cost but as you said, you've put enough money into it.

Then it comes down to deciding how much another pump would cost. If the pump can't get down to a few microns (via a properly working gauge), then frankly, at that point, you have nothing to lose and a further break down would appear worthwhile. Failure and maybe just get rid of the pump. Success and you have the pump and at an acceptable cost. Of course, you could still buy a rebuild kit if you decide to keep it after discovering the o-rings are a once use only. Your call.

If you do decide to dis-assemble the vacuum stages (at some point), remember to take photo's to reference for re-assembly and keep the order correct for all stages during cleaning. They need to be re-assembled as they were originally.

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Re: Cleaning/Repairing Edwards E2M5

Post by Ameen Aydan » Thu Feb 14, 2019 5:40 pm

Hello,

I think I will just go ahead with that route. I have seen people do it on these forums in the past so why not give it a go. If it doesn't go well and this thing is a peice of trash, then at least I know that I got my money back on it. I told the seller about the condition this pump and he refunded me all the money. I only spent money on the oil and gasket. About $100 as of now.

As for the gauge, the seller told me it was calibrated and in working condition. If that's the case then my pump is infact shitty. Maybe it's the Teflon seal? I dunno.

I will go ahead and disassemble the pump. Because i just put in the new oil yesterday I will just reuse it and filter it.

Do you know by any chance how long it took you? Do you think I can reuse the oil if it's that new, and unused? And last but not least, what is that silicon thing you were talking about? You don't have to answer the questions.

I fixed the Google drive link

I'll send an update soon.

Ameen Aydan

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Re: Cleaning/Repairing Edwards E2M5

Post by Bruce Meagher » Thu Feb 14, 2019 6:09 pm

Before you disassemble your pump are your sure you don't have a leak around the BSP threads on the intake flange? I know I steered you to the inexpensive intake flange, and as I mentioned this cheap version does not have a proper o-ring seal. The BSP threads are straight making it a little more difficult to seal. Are you just using a few wraps of teflon tape? You could try adding vacuum sealing tape, melt some beeswax around the fitting interface, use liquid teflon, or even try a few drops of vacuum oil at the interface to see if you have a leak here.

edit: I didn't read your post closely enough. I see you reached 13 mtorr previously, but now are only getting to 10 Torr. Something doesn't make sense. I think you have either created a leak between runs or your gauge is fouled.

Bruce
Last edited by Bruce Meagher on Fri Feb 15, 2019 12:59 am, edited 2 times in total.

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