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| Suggestions for forums for Vacuum Systems? |
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| TerraHertz:
Does anyone know of an active and informative forum (like eevblog) on vacuum system practices and materials? Googling finds: http://belljar.net/forum/ But registrations are closed, and the posting history reveals it to be a virtually dead forum, and has been for years. Possibly the owner's demand that people register using their real names may have something to do with that - there's no way I'd consider that an acceptable condition. And whhyyyyy would anyone keep a zombie forum online? https://www.physicsforums.com/#physics.9 Only has a few vacuum-related posts now and then. Not suitable. http://www.fusor.net/board/viewforum.php?f=10 Vacuum Technology (& FAQs) Quite active, and interesting. But sadly, they flatly demand real name registration. And I flatly refuse. Surely there must be at least one vacuum-systems forum that is both active and has sensible registration rules? I'm refurbishing an old Edwards Speedivac 2SC20A rotary vacuum pump, and need advice on things like best solvent for final rinse before reassembly, and material for making new oil seals. This is just for practice, before attempting check & clean rebuilds of larger, better rotary vacuum pumps I have. Also I have the user manual and have scanned it, but can't find any service manual online. Possibly the model is so old there wasn't ever such a manual. In fact I have two copies of the user manual (both undated) but the earlier one uses "mm of mercury" for all pressure measurements, while the later one replaces that with Torr (exactly the same unit, just different name.) That would date it, except I don't know when 'Torr' became widely adopted. Mine is the center one in the pictured group. I'm doing a photo-writeup of the refurbishing, and will post when done. |
| amyk:
I thought you were asking for a forum on vacuum cleaners... --- Quote from: TerraHertz on November 25, 2015, 02:59:33 pm ---But sadly, they flatly demand real name registration. And I flatly refuse. --- End quote --- Does it matter? https://fakena.me/ and you're done. ;) |
| calexanian:
I have never rebuilt any of those particular Edwards pumps but most of them are similar enough to the Welch and Kinney type designs that many things hold true for all of them. First of all the actual vacuum pumping seal is made by the oil itself between the vanes or rotor and the inside of the pump wall itself. If both are still smooth you should be fine. Most leaks occur in the exhaust valve seal in those types of pumps, or the shaft seals. Also gas ballast valves can be problematic. Generally there are no seals to speak of between the internal pump wall and the face plates as thees are precision ground surfaces and the oil itself maintains the seal. Generally you can fill the pump with oil. Turn it by hand a few times, then plug the inlet and turn it a few more times by hand. If you hear any gurgling back into the pump you have a leaking exhaust valve. This may be of a reed or ball type and sometimes rarely a tappet valve type. As far as cleaning I just use engine degreaser like if I were cleaning any steel engine component. Berrymans Chem DIp works well for carbon deposits. I also clean with warm soapy water and then just water and then use brake cleaner. Do not touch parts at that point with your fingers or the acid and stuff from your hands can make a dirty or rusty spot down the road. Coat everything in pump oil and re assemble it. Also when its all back together feed a few tablespoons of oil through the pump to help build up the initial film on everything and force it into all the places it needs to go. That's pretty much my procedure for doing Welch pumps and I cannot imagine that Edwards being much different. I already looked and could not find a kit for that one. Its simply too old. Thats why i always stick with Welch because rebuild kits are readily available. Good 1400, 1405, and 1402 pumps can be had fairly often and at reasonable prices. |
| TerraHertz:
calexanian, thanks for the hints. The rebuild is going OK, and I managed to find info on the net that I needed. But practical tips like yours are rare, thanks. The story of that pump is here: http://everist.org/NobLog/20151112_planning_vacuum.htm (Mixed in with random other stuff. Scroll down. Still in progress.) This was useful too: http://vacuumcursus.nl/casussen/Cleaning_Chapter.pdf CLEANING FOR VACUUM SERVICE Btw, can you suggest any possible sources for a cheap turbomolecular pump? I've been looking for one I can afford for years, no luck. Ebay ones are almost invariably too pricey AND missing the controller. Recently a possible source came up, but it's looking like nothing will come of it. Person involved seems to think turbo-pumps may be prohibited exports from the USA to Australia. And proving they are not, given the complexity and incomprehensibility of US gov online red tape, defeats me. Pic of my vac chamber below. Bottom port is intended to connect to the big oil diffusion pump below it, via a gate valve and cold trap. But I _really_ don't want to use the diffusion pump. |
| TerraHertz:
--- Quote from: amyk on November 26, 2015, 04:08:40 am --- --- Quote from: TerraHertz on November 25, 2015, 02:59:33 pm ---But sadly, they flatly demand real name registration. And I flatly refuse. --- End quote --- Does it matter? https://fakena.me/ and you're done. ;) --- End quote --- That could work. But there are two more subtle issues. One being honesty. Nothing wrong with using a nic where that's accepted practice (like here, and *most* net venues.) But when a site demands real names be used, and you fake it, that's dishonest. I'm not willing to do that, regardless of their reasons. Their demand for real names also makes me paranoid, about *why* they want real ID. In the case of Fusor.net I think I have a pretty good idea, and it's not their stated reason. I don't want to touch it with a pole. Not even an 'anonymously' redirected pole. There's no such thing as true anonymity on the net anymore, from eyes that matter. |
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