Progress on my fusor

Current images of fusor efforts, components, etc. Try to continuously update from your name, a current photo using edit function. Title post with your name once only. Change image and text as needed. See first posting for details.
MatthewL
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Re: Progress on my fusor

Post by MatthewL » Thu Aug 03, 2017 12:04 am

Before I had gotten either of these responses I had decided to change the oil. I have already done one oil change before when I disassembled the pump to clean it. When I did the first oil change, the oil was black (It was light yellow when I had originally put it in). The black color of the oil and the fact that the pump was not working is what drove me to disassemble the pump to clean it. The inside of the pump was very dirty and all I had done was wipe down most of the black residue that was covering a lot of the pump with a cloth. I then reassembled the pump filled it with new oil and that is how I have been using it up to now. Before I had gotten the responses I drained some of the oil to see what color it was, and it was the same black color as before. I thought maybe I did not clean the pump well enough, so I did some searching on the internet and read some websites on rebuilding rotary vane vacuum pumps and realized that I other people where using a solvent like acetone or petroleum ether and wire brushes and steal wool to get all of the parts very clean. So I just spent yesterday completely disassembling my pump and thoroughly cleaning it. I didn't have quite enough oil left to test it so I ordered some more and it should be here on the fourth. August 4th also happens to be my birthday so I will not be achieving fusion as a fourteen year old as I had wanted to (although it was not very important to me). I cleaned the pump as if I was doing a rebuild, but I did not have a rebuild kit to replace any O-rings or gaskets. I would like to do a rebuild at some point in the future, but I can't find a rebuild kit for this model in particular (Edward's EDM12). In fact I can't find much information of any kind on this pump besides the few for sale on eBay and LabX. If any one knows anything about it or knows of a rebuild kit for it I would be interested knowing about it. If there is no rebuild kit for this model I would still like to change the main gasket that seals the oil within the body of the pump, as the gasket is fragile and very slowly will leak a couple drops of oil. The gasket appears to made out of cork, but before I order a sheet of cork gasket material and cut out the correct shape I am curious if maybe it is a particular kind of cork for these pumps, or if maybe there is a completely different material that is even better?
This is the oil that I have been using: https://www.duniway.com/part/mpo-190-1. I chose this one mainly because it was the least expensive, but there where some other options. If there is a better oil to use, and it is not the ridiculously expensive oil like fomblin, I might want to switch.

Thanks,
-Matthew

Rex Allers
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Re: Progress on my fusor

Post by Rex Allers » Thu Aug 03, 2017 9:51 am

Matthew,

When I read that you had an Edwards EDM12 I thought it might be a typo. I have an E2M12 pump. With a bit of web searching I see that the EDM is an older version. Looking at the Edwards site I don't see my E2M12 being sold now but there is no mention of the EDM. One link I found was this one, which seems to indicate parts for EDM pumps are hard to find...
http://vacuumandlowpressure.com/oldEdwardsParts.html

So, my Edwards E2M12 had major problems when I got it that started with not very good vacuum and moved to a pump that wouldn't spin. I managed to get most of my purchase price back and used it to buy a total rebuild kit. A lot of work followed. I know that there is a small score on one of the rotors now but it does pump down to ~5-10 mTorr.

Problem came because it was used to pump for fiberglass molding and sucked many bad things through it. Actually this was second pump with this bad life... 1st yet to be saved, maybe never.

So it is unlikely that you can find parts to rebuild yours. Hopefully any problems can be fixed with the cleaning or something simple. If not, I don't think I'd try to get into the internal pump unit without documentation or rebuild parts. That may make a marginal pump a boat anchor.

So, on your first questions, I think the oil you used was fine. Part of the blackening of the replaced oil may be what was still in the pump mechanism itself. Hope things are better on your second pass. Duniway does sell a flushing liquid that is cheaper than the real oil if it comes to that, but probably not worth it if 2nd try is still bad.

So more important, I think, is that the symptoms you described earlier sound odd.

On my OK working E2M12, here's how it works. As I start it up it gurgles a bit as it pulls down a vacuum. When the vacuum is settling in the pump itself is pretty quiet. The motor obviously makes noise but I'm talking about sounds out off the pump section. Let's say I have a vacuum gauge on the pump and it gets to 20 mTorr at lowest. Now I might open the ballast a bit. This lets air into the pumping chain in the pump. While the ballast is open the sound will be gurgling a bit and the exhaust will have more oil vapor. The vacuum gauge will go up a bit (less vacuum) while the ballast is open. Normally you would run with the ballast open for a long time, then close it. Pump should stop gurgling. If the ballast cleaned anything out of the oil, the pressure should go lower than before.

Your description of what your ballast valve is doing does not sound right. You said your maximum vacuum was with the ballast open. That's not normal. You said with the ballast closed the pressure went up and you could hear the ballast drawing air. Both of those are wrong indications. Can you provide any info on the sounds (gurgling, quiet, etc.)?

Not sure how the ballast works on this thing. Can you unscrew it entirely out of the pump and try to figure out how it should work? Maybe something is not sealing or who knows what.

If I remember right from my work on the E2M12, the ballast led to a tube that allowed air into the 2nd pump (lower vacuum side rotor) just for reference of how it might connect.

I wouldn't mess with the case gasket until you decide if this pump is worth more effort. If it is and you can't find one to buy, I'd go to the auto parts store and buy a roll of gasket material. I'd go for one like thick paper rather than cork. With the pump case open, lay the case on the gasket (on a flat surface) and trace around it with a pencil. Measure thicknesses of the case lip and transfer to draw inside lines on the gasket.
Pressing the gasket onto the parts with your fingers may help to find hole locations. Cut with scissors, exacto knives, paper hole punches, or whatever. On the holes, you can make one punch (too small) and then eat it out with more punches or an exacto while on the part. Some ideas. Use your own creativity as you go if it comes to this.

Good luck. Hope your pump is not a basket case. I'd start with trying to figure out why the ballast valve seems weird. Here's a link to what it is supposed to do.
http://www.edwardsvacuum.com/asia/newsl ... sk_en.html
Rex Allers

John Futter
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Re: Progress on my fusor

Post by John Futter » Thu Aug 03, 2017 10:12 am

We have two of these at work and 4 years ago we did manage to get rebuild kits from Edwards

warning after dissassembly you have to put a little oil down the inlet or you run the risk of seizing the rotors -- we did this once --gets expensive with a second recon kit

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Richard Hull
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Re: Progress on my fusor

Post by Richard Hull » Thu Aug 03, 2017 3:19 pm

I hear a lot of horror stories here about mechanical pumps. I guess I have been lucky. The worst pump I ever bought struggled to hit 25 microns after a good 3 oil change, run for hours, change oil, run for hours, etc.. It was a well worn Welch 1200 which is kind of whimpy to start with. (1CFM). I will admit, I have bought 100% of my pumps locally, finding most of them for sale in our local 7-11 distributed rag, "The Trading Post".
I took a little battery operated, CVC TC gauge with me before I gave up the bread. That helped a lot.

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.

MatthewL
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Real name: Matthew Lallinger
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Re: Progress on my fusor

Post by MatthewL » Sat Aug 19, 2017 3:47 pm

After I cleaned the pump I began to reassemble it. After it was fully reassembled I went to turn the motor on, but it wouldn't spin. The motor is definitely working but it is the shaft for the actual pump which won't turn.
IMG_0235.JPG
IMG_0236.JPG
I included an exploded view of the pump so it is easier to understand what I am taking about.
I thought about what could be the problem for awhile, and after disassembling the pump again and trying to spin the shaft with various parts attached, I determined that the resistance is where the shaft (number 5, 12, 13 in exploded view) meets with the area labeled 80 on exploded view. I realized that this resistance is only present only when the bolts are fully tightened.
IMG_0231.JPG
in this photo the bolt is tightened (there are six bolts that go around to hold it in place, I only show one but the same affect happens with all six) and the shaft can not be turned barely at all.
IMG_0232.JPG
I then loosen the bolt a few turns
IMG_0233.JPG
now I can spin the shaft by hand, but there is still a lot of resistance. Oddly, as I spin the shaft it is easier to spin for most of a revolution but at one point per that revolution it becomes even my difficult to turn, and then it goes back to being easier until it reaches that point again.
IMG_0234.JPG
I thought it might have been the shaft seals that where to old so I emailed the person behind the website that Rex provided, vacuumandlowpressure.com, and he sent me a rebuild kit for my pump that also included the manual that had this exploded parts view. I just completed doing a full rebuild of the pump last night and the same problem is still encountered. Also I coat all of the parts in a little pump oil before I reassemble it.
I know that what I am trying to explain is pretty tedious so if something needs to be clarified just ask.
If anyone knows why this problem might be happening I'de appreciate the help.

Thanks,
-Matthew

Bruce Meagher
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Re: Progress on my fusor

Post by Bruce Meagher » Sun Aug 20, 2017 1:42 am

Have you tried removing the vanes (labeled 29 on the parts list) and retightened the bolts to see if they are the cause? Since the pump was working previously maybe you just reinstalled the vanes incorrectly.

MatthewL
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Real name: Matthew Lallinger
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Re: Progress on my fusor

Post by MatthewL » Wed Aug 23, 2017 1:41 am

The vanes did appear to be adding some to the resistance. It turns out that one of the vanes was in backwards. There is a groove on the first stage vanes that is supposed to face in the direction of rotation and one of the vanes was not. After fixing that problem, adding even more oil as lubrication, and removing the cam from the shaft all of the resistance disappeared. When the cam is on the shaft, it causes the issue that I had talked about that is increased resistance in only in one place as the shaft is turned. With the cam it is only this intermittent resistance. I believe that I either need to flip the cam around in the cam housing (or oil pump) or I need to prime the pump as per the manual's instructions by placing my finger over the outlet of the pump for a few seconds intermittently to help increase internal pressure thus pushing more oil into the oil pump. I will try those things this weekend. If I still can't get the pump to pump correctly I do have a backup plan for my pump it is a Sargent Welch "Sarvac 8804" pump which I bought brand new with an oil mist filter and a foreline oil trap for a great deal on Ebay. The only downside of the pump is that it is small and can only pump at .9 CFM and will overheat if on for extensive periods of time, but it is two stage.
Also Edward's finally shipped me my dipstick and oil drain plug for my diffstack.
IMG_1031.JPG
They aren't what I had expected as they do not have threads. Do any Edward's Diffstack owners know if this is supposed to have another part with it? Possibly a threaded part that goes over it to hold them in place. I do have my lathe now so I luckily will be able to machine a threaded part to hold them in place if necessary.

Thanks,
-Matthew

John Futter
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Re: Progress on my fusor

Post by John Futter » Wed Aug 23, 2017 5:29 am

Yep a knurled hollow nut that clamps down on that larger diameter bit

MatthewL
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Real name: Matthew Lallinger
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Re: Progress on my fusor

Post by MatthewL » Fri Sep 01, 2017 10:09 pm

I have a lot of extra time because there will be no school until Tuesday (due to Hurricane Harvey). I spent some of that time working on my first lathe project that was not just practice. I turned two of the hollow nuts for my diffstack oil drain and dipstick and they helped very slightly for any very minimal leaking I already had. I also got a chance to do a first test of the diffstack which was successful. I pumped down my system to the point where my pirani gauge was bottomed out (well bellow 1 micron). Because I still can't get my EDM12 to work properly I had to use my Welch Sarvac 8804 pump which worked fine. I have a hot cathode ion gauge but it doesn't seem to work. I have to do some testing to see where the problem is exactly, but from the minimal testing I have done so far I believe it is only the LCD screen on the controller which won't turn on, so it should hopefully be an easy fix. Now that I have my vacuum system working I should be able to achieve real fusion after I complete only a few minor things with other parts of the system. I should hopefully be posting on my working fusion reactor in the next couple of days, if no other problems arise.
I appreciate all of the help I have gotten on this thread.

Regards,
-Matthew

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