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Hello guys! I have finally built together a small simple high vacuum system with a diffusionpump and the vacuum only goes up from little under 1 milliTorr to 1.2 Torr in 2 days when all valves are shut and that is fine with me so it is holding the vacuum ok as i see it, might also be some degas involved. I want to test the diffusionpump ASAP so i can start making small mirrors but i dont know if the shutdown procedure i think of is right to do without a gatevalve. The diffusionpump is connected directly to the chamber the rest is built with one valve to its discharge and one valve to the chamber and these two are then connected to a tee and then the this is connected to the backing pump with a bellow tube and thats it. To start it all is of course very easy but to shut it down with only two valves is something i want to be sure on if it works as i think of to do so without getting oil into the chamber or anything. This is what i think might happen and/or will work and when i shut it down it all has to do with the diffusionpump as i see it: As long as it is hot it pumps and thus must have the backing pump going all the time i guess or could the discharge valve be closed right away or as soon as it is only a little cooler? The very small amount of air in the bottom wont cause any oil to go into the chamber since this air will try to go up into the chamber and draw any oil from the oil curtain with it? Or should i carefully monitor the discharge pressure and as soon as it starts to go down i shut the valve since i then see this to indicate that the dp is so cool that it cant hold down the air in the bottom anymore so air is then starting to be sucked back through the pump into the chamber from the discharge? Will any of these scenarios work or will it pull back oil into the chamber or doesnt it matter since there might be so little air in the lower part of the diffusionspump that there wont be any problems at all no matter what i choose to do? Im very concern of this so it wont go south very quickly all of a sudden, so any help with this would be highly appreciated so i know if this might work with only 2 valves and no gatevalve to the DP. Thanks a lot! Regards Henry

Hello... I need to make vacuum in range 5 to 10 mBar. What device to use for that. I need to evacuate aprox 5 litre box but I do not have electricity on place where I need to do that. What options I have? Thanks

How often do you experts clean out and replace the oil in a roughing pump? How about in a diffusion pump? We did the Diff pump about 10 years ago, and found all kinds of interesting stuff had fallen into the trap. The roughing pump (a Welch, IIRC) probably hasn't been cleaned out in over 20 years. Guy

Finally, the penny drops! In the last forty years the structure of even the simplest zeolite (A) has been investigated and its uses as adsorption and catalytic surfaces has been investigated. Here is a straightforward paper on the topic http://engineering.ucsb.edu/~yuen/references/ref-2.pdf Recently people have been interested in zeolites as heat exchangers. This is a demo model of the kind I expect that triggered this thread. http://www.rexresearch.com/zeolite/maier.htm Zeolite (etymology "boiling rock", for its exothermal behavior in adsorbing up to 30% by weight of water) is an interesting material. Zeolites are ideally heated to 250degC to desorb the attached water again. But lower temps can release a fair proportion of the water. Now having got those facts out of the way, its time to mention something else interesting: If a dry zeolite is pumped down in the presence of water vapor, the zeolite will self-pump down further. An attractive primitive pump down method presents itself: given a side water reservoir and an air reservoir connected with taps, the classical method of steaming out the air reservoir and chilling it down with waste water, then connecting to the chiller system, several times will pull the chiller pressure down enough for the zeolite to work its magic, given three gas taps are plumbed in to give the desired evacuation sequence. A suitable scavenged container might be provided by a used propane cylinder or two, which can take the vacuum easily. Brian Whatcott Altus Oklahoma

Esteemed list members: I have just acquired an Ametek / Dycor M100 RGA system (in 4 pieces from three different sellers) Does anyone have available the operation and service manuals to sell, copy, or scan? Thanks, Dave

Hi All, I am in urgent need to sale vacuum chamber: Leybold A700, framed, with installed gate valve, LN2 trap, two-ways roughing valve, transformer for resistive evaporators, water and compressed air communications. Chamber is clean, painted, gate/valve reassembled and cleaned, no visual defects obtained. Plus some other small staff (feedthroughs, tooling, etc) available. Plus diffusion pump DIP3000 for that chamber - Leybold brand produced in Russia, brand new in manufacturer's not opened package (no oil filled and no heater cartridges installed!). Picture and more detailed information on request. Thanks, Vladimir Chutko

LinkedIn I'd like to add you to my professional network on LinkedIn. - Christian Christian Oertli Independent Research Professional United States Confirm that you know Christian ? 2011, LinkedIn Corporation

Hi All, Because I didn't get reaction and I anyway searched a solution. I found a patent which is an improved diffusion pump description. It gives me answers to my question and gives ideas how to improve the speed of my diffusion pump. If anybody interested, I uploaded the patent pdf in the files section. Regards Attila The Hun

Hello, This email message is a notification to let you know that a file has been uploaded to the Files area of the VacuumX group. File : /US3363830.pdf Uploaded by : schneyolo <schneyolo@...> Description : Diffusion pump patent You can access this file at the URL: http://groups.yahoo.com/group/VacuumX/files/US3363830.pdf To learn more about file sharing for your group, please visit: http://help.yahoo.com/l/us/yahoo/groups/original/members/web/index.html Regards, schneyolo <schneyolo@...>

Hi All, I have a question to diffusion pump, pumping speed. Is there any equation or math to calculate the pumping speed? Or what factors are important to determine the pumping speed. I ask this, because I have a BAlZERS diff. pump wich has a 160mm throat. And it is capable to make 250L/s speed. But I just found the Varian VHS-6, wich has a 6" inlet and capable to 1550L/s pumping speed. The Varian needs the same backing pump capacity like mine Balzers 29cubik meter/hr. At first glance the main difference between mine and the Varian , the Varian has a bulk on the upper quarter. I read somewhere this bulk feature improves the pumping capaicty. If it is tru than why does it. Any idea? Regards Attila The Hun

Hi, This is my first post in the group. I want to know the tolerance in thickness variation (in nm) of Aluminium coating, acceptable and expected from professional and amateur coaters. Mr Jan van Gastel in interferometry group has finished a mirror accurate to <5nm. So I think coating error introduced in 100 nm film thickness would be less than 1 nm. Is such precision achieved routinely by coaters in this group? Thanks and with regards, Deepak Ahmedabad, India

I have just added another moderator to the VacuumX Group. David McGuire, located in Florida USA, has expressed an interest in keeping the Group running smoothly. Currently Thomas Janstrom in Australia is a co-owner of the Group with myself. I am moving on this summer if all goes well, Thomas is returning to studies at University and will be busily engaged there so please welcome Dave in his efforts to help keep the Group going. So far we've been able to keep the group on-track and keep the bad guys out. I thank everyone for their participation, information, and being there to help those in need by answering questions etc... Great bunch of guys here! Ken - KB7H

As Javaguy mentioned, I have sold the diffusion pump stacks, roughing pumps, baseplate and misc other items. Will be delivering it all to him in a couple of weeks. I have listed several small items on eBay that are not part of this sale and will be listing some more misc items and junk to clean out the barn. Once it's gone, I will be out of the vacuum hobby. It's been a nice run and I'm glad I've had a chance to meet you guys. I'll be turning over the reigns to VacuumX once I get the remaining items I have sold or given away, whatever the case. Anone that might want to take over the ownership of the Group, contact me privately. There seems to still be a lot of (though mostly silent) interest in keeping the Group open. I don't know what my Internet options will be when we relocate to Costa Rica so it would be prudent to make some arrangements ahead of time. Thanks guys... Ken - KB7H

Still have the diffusion and roughing pumps, valves, etc for sale - What no offers? Ken Hunter

Hi Ken what kind of diffusion pump do you have and how much.thanks ed edsworkshp

I stumbled upon this group when I was searching for MgF2 coating service suppliers. The whole vacuum coating technology is amazing, I hope I can experiment on this one day. Here is my question: any members of this group provide a MgF2 coating service? I've got a badly damaged camera lens with various coating damages on internal lens surfaces. Would anybody be interested in coating bare lenses with MgF2 if I prepare (clean, strip, polish) and send them? How much would you charge for lets say 5-6 lenses, and one of them is cemented, would this cause issues? Kind regards, and sorry if this is an odd question, please ignore if it is! Koray

Hi Guys, I recently retired and find that I not have the resources to continue living in Illinois due to several factors. Among them are continuing medical expenses incurred a few years ago when Rose came down with cancer. At that time I had to sell my 26.5 inch mirror, grinding machine, tools, HAM Radio equipment, etc to pay some of the bills. In all, the recent economic downturn, lack of sufficient savings, increase in the cost of living coupled with lower than expected retirement income is causing us to rethink our futire. One sad story among many I believe. Because of this, we are hoping to relocate to Costa Rica. In order to do this, we are going to sell our home. Sell, give or throw away EVERYTHING we have left that we don't anticipate we will take down to Costa Rica with us. I still have many books, a 10 inch refractor lens assembly with fiberglass OTA, 2 ea 20X3 inch Fused Quartz octagonal shaped disks to be generated round, Vacuum deposition equipment, Telescope making and HAM Radio parts, Tools, etc... much too too much to list individually here in the time we have left before departure. I have saved this stuff over many years with intentions of doing something with it. These are my treasures and are too good to throw away but I know that I will not be able to move it all individually on Craigslist or eBay and really don't relish the thought of parting it out to strangers. I have had to come to the realization that this stuff is just that... just stuff. So... If you have a truck, a few dollars and a plan, get in touch, make an offer. For the larger items that sell, I might be enticed to deliver as long as it's not a negative cash flow for me. If you want specific information regarding what I might have for sale or to give away and are interested in picking it up or having it delivered, please contact me directly. Thanks Ken Hunter atm_ken_hunter@... (217) 445-2023

Granville-Phillips Vacuum controller and Gauges have been SOLD and are headed to Andrew in Sunny Florida. Still have the 6 inch Diffusion pump stack of equipment seen on page 2. Looking for offer, if none received, I'll put it on eBay next week. Willing to work on shipping and possibly meet half way or ??? Ken - KB7H

Hey gang, I finally got around to putting a water chiller on my coolant loop for the diffusion pumps and it made a big difference. I now have to insulate the water jackets because they get so cold they sweat. The water in the jacket is like 32 degrees now. The pump down time with the heaters on went from 4+ hours to about 45 minutes and the overall vacuum seems devoid of oil vapor. I saw no soot on the windows for the first time ever. I only have the one run to judge by ( using the new coolant system ) but it really looks like it makes a huge difference in the chamber’s abilities. Drew in smoky FLA

Just looked and there is a wide variance in price for vacuum pump oil. Probably the best deal was 4 Gallons of Robinaire Premium Hagh Vacuum pump oil for $71.99... That's only 18 per gallon. Also say same item for $110.00 shipped free. Wait until you spring for a gallon of Dow 704. It's like buying a good insecticide. Cheaper to vacuum coat the bugs. Have fun. Ken - KB7H