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Re: [VacuumX] The vacuum tank known as

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  • Gomez Addams
    ... As you say, there s not much He in the atmosphere. Won t it take a rather long time for a significant amount of He to enter the chamber? A surprising
    Message 1 of 15 , Feb 1, 2007
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      On Jan 29, 2007, at 4:00 PM, Thomas Janstrom wrote:

      > James/Gomez,
      >
      > If there is a glass window into the chamber you will end up
      > filling the volume with helium, a nice and hard to pump gas. This
      > is because for helium the glass might as well not be there at all….

      As you say, there's not much He in the atmosphere. Won't it take a
      rather long time for a significant amount of He to enter the chamber?

      A surprising number of chambers seem to have transparent glass
      ports. Very thick ports to be sure. I wonder how they manage to
      achieve good vacuums?
      > Glass isn’t very hydrogen permeable,

      Strange - why would anything be LESS permeable to H than to He?
      After all, He has a denser nucleus than H!

      > but steel is to some extent (mainly in welds and other joints)
      > however this is to a much lower extent that the helium permeability
      > of glass, it’s a good thing that there is so little helium in the
      > atmosphere!

      Yes - about 1:200,000!


      ..............................................
      Railguns, Tesla coils, and computers are easy.
      It's understanding people that is difficult.
    • Anderson, Gordon (Hovensa)
      Helium may permeate more easily than Hydrogen because it does not make bonds as easily as Hydrogen. Gordon ... From: VacuumX@yahoogroups.com
      Message 2 of 15 , Feb 1, 2007
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        Helium may permeate more easily than Hydrogen because it does not make
        bonds as easily as Hydrogen.


        Gordon




        -----Original Message-----
        From: VacuumX@yahoogroups.com [mailto:VacuumX@yahoogroups.com] On Behalf
        Of Gomez Addams
        Sent: Thursday, February 01, 2007 10:42 AM
        To: VacuumX@yahoogroups.com
        Subject: Re: [VacuumX] The vacuum tank known as



        On Jan 29, 2007, at 4:00 PM, Thomas Janstrom wrote:

        > James/Gomez,
        >
        > If there is a glass window into the chamber you will end up
        > filling the volume with helium, a nice and hard to pump gas. This
        > is because for helium the glass might as well not be there at all....

        As you say, there's not much He in the atmosphere. Won't it take a
        rather long time for a significant amount of He to enter the chamber?

        A surprising number of chambers seem to have transparent glass
        ports. Very thick ports to be sure. I wonder how they manage to
        achieve good vacuums?
        > Glass isn't very hydrogen permeable,

        Strange - why would anything be LESS permeable to H than to He?
        After all, He has a denser nucleus than H!

        > but steel is to some extent (mainly in welds and other joints)
        > however this is to a much lower extent that the helium permeability
        > of glass, it's a good thing that there is so little helium in the
        > atmosphere!

        Yes - about 1:200,000!


        ..............................................
        Railguns, Tesla coils, and computers are easy.
        It's understanding people that is difficult.





        Yahoo! Groups Links
      • Aurigema, Andrew N. (KSC)[ASRC AEROSPACE]
        Helium is mono-atomic ( GHe ) in almost all of its free states where as Hydrogen is almost always diatomic ( GH2 ). The volumn of the electron shell of GHe
        Message 3 of 15 , Feb 1, 2007
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          Helium is mono-atomic ( GHe ) in almost all of its free states where as Hydrogen is almost always diatomic  ( GH2 ).  The volumn of the electron shell of GHe is less than the combined GH2 shells.  One of the reasons that He is as screwy a gas as it is.
           
          I pick up baby George the vacuum chamber this Saturday.  It promises to be a very long day with 8 hrs of driving in the loop.   
           
          Andrew  


          From: VacuumX@yahoogroups.com [mailto:VacuumX@yahoogroups.com] On Behalf Of Anderson, Gordon (Hovensa)
          Sent: Thursday, February 01, 2007 11:30 AM
          To: VacuumX@yahoogroups.com
          Subject: RE: [VacuumX] The vacuum tank known as

          Helium may permeate more easily than Hydrogen because it does not make
          bonds as easily as Hydrogen.

          Gordon



          -----Original Message-----
          From: VacuumX@yahoogroups .com [mailto:VacuumX@yahoogroups .com] On Behalf
          Of Gomez Addams
          Sent: Thursday, February 01, 2007 10:42 AM
          To: VacuumX@yahoogroups .com
          Subject: Re: [VacuumX] The vacuum tank known as

          On Jan 29, 2007, at 4:00 PM, Thomas Janstrom wrote:

          > James/Gomez,
          >
          > If there is a
          glass window into the chamber you will end up
          > filling the volume with
          helium, a nice and hard to pump gas. This
          > is because for helium the
          glass might as well not be there at all....

          As you say, there's not much He in the atmosphere. Won't it take a
          rather long time for a significant amount of He to enter the chamber?

          A surprising number of chambers seem to have transparent glass
          ports. Very thick ports to be sure. I wonder how they manage to
          achieve good vacuums?
          > Glass isn't very hydrogen
          permeable,

          Strange - why would anything be LESS permeable to H than to He?
          After all, He has a denser nucleus than H!

          > but steel is to
          some extent (mainly in welds and other joints)
          > however this is to a much
          lower extent that the helium permeability
          > of glass, it's a good thing
          that there is so little helium in the
          > atmosphere!

          Yes - about 1:200,000!

          ............ ......... ......... ......... .......
          Railguns, Tesla coils, and computers are easy.
          It's understanding people that is difficult.

          Yahoo! Groups Links

        • Gomez Addams
          On Feb 1, 2007, at 10:14 AM, Aurigema, Andrew N. ((KSC))[ASRC ... DOH! I knew that, once, I just forgot it. I feel like a moron.
          Message 4 of 15 , Feb 1, 2007
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            On Feb 1, 2007, at 10:14 AM, Aurigema, Andrew N. ((KSC))[ASRC
            AEROSPACE] wrote:

            > Helium is mono-atomic ( GHe ) in almost all of its free states
            > where as Hydrogen is almost always diatomic ( GH2 ).

            DOH! I knew that, once, I just forgot it. I feel like a moron.

            ........................................................................
            this message was made possible by: Bill Lemieux, Gomez A.D.D.ams, Arkoff
            Kapacitor, The Mad Scientists Club, The Denver Area Science Fiction
            Association, The National Security Agency, The Defense Advanced Research
            Projects Agency, the Echelon system, the letter 'Q', and the number '7'.
          • dean@electricmist.com
            For a while Varian resold Alcatel vacuum pumps that look just like the one in your picture. The Varian pumps were SD-xx series, where the x refered to the
            Message 5 of 15 , Feb 6, 2007
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              For a while Varian resold Alcatel vacuum pumps that look just like the one in your picture. The Varian pumps were SD-xx series, where the x refered to the model number or capacity.  Varian pumps had a tan paint on the pump and black or brown motors.  Alcatel pumps almost always had orange or black paint on the pump body. Alcatel parts will work for you, but I cannot identify the specific model from the picture.
               
              Dean
               
               
               
              -----Original Message-----
              From: Aurigema, Andrew N. \(KSC\)[ASRC AEROSPACE] [mailto:andrew.n.aurigema@...]
              Sent: Tuesday, February 6, 2007 04:50 AM
              To: VacuumX@yahoogroups.com
              Subject: RE: [VacuumX] The vacuum tank known as " baby George"

              Hi Gang.
               
              The (new to me) baby vacuum chamber is now located at my hanger.  It was a fun weekend moving that thing a few hundred miles but nobody got killed and nothing important got broke.
               
               
              Now I just have to make it hold vacuum.  James and I are thinking of making a vac/melting oven out of it so we can make mirrors from scratch.  
               
              Oh,  can anybody identify this pump ??? http://ph.groups. yahoo.com/ group/VacuumX/ photos/view/ bd69?b=3 
               
              It has a 3 hp motor on it but no identifiers on the vac pump section.  I am going to take it apart and wanted to get a rebuild kit for it.  Any help would be appriciated.
               
              Andrew


              From: VacuumX@yahoogroups .com [mailto:VacuumX@ yahoogroups. com] On Behalf Of James Lerch
              Sent: Friday, January 26, 2007 4:09 PM
              To: VacuumX@yahoogroups .com
              Subject: [VacuumX] The vacuum tank known as "George"

              OH BOY...

              Andrew purchased a vacuum tank, and WOW what a vacuum tank.  Words can't adequately describe the dimensions involved, but I think it is safe to say his itty bitty Welch 1397 17cfm (500L/min) pump ain't gonna cut the mustard :-0

              http://lerch. no-ip.com/ atm/Projects/ Drew_tank/

              So, I'm thinking he's going to need 2 or 3x 1397 pumps in parallel, all being fed by roots type blower to get the CFM up?  Then, where do you find a 20" diameter diffusion pump?  Is there a practical limit for the number of diffusion pumps that can be paralleled?

              Since Drew is looking to coat 40inch mirrors, I'm thinking the first thing we need to do is break out the plasma cutter and knock 4 or 5 feet off the length of that chamber!

              Like I said, OH BOY.

              -- 
              Take Care,
              James Lerch
              http://lerch. no-ip.com/ atm (My telescope construction, testing, and coating site)
              http://lerch. no-ip.com/ ChangFa_Gen (My 15KW generator project)
              
              "Anything that can happen, will happen" -Stephen Pollock from:
              "Particle Physics for Non-Physicists: A Tour of the Microcosmos"
              
              " Press on: nothing in the world can take the place of perseverance.
              Talent will not; nothing is more common than unsuccessful men with talent.
              Genius will not; unrewarded genius is almost a proverb.
              Education will not; the world is full of educated derelicts.
              Persistence and determination alone are omnipotent. " 

            • Aurigema, Andrew N. (KSC)[ASRC AEROSPACE]
              Dean, Thanks. With that info I was able to determine that the pump is a Alcatel 2063 that has a strange paint job. I found repair parts for it and now can
              Message 6 of 15 , Feb 7, 2007
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                Dean,
                 
                Thanks. 
                 
                With that info I was able to determine that the pump is a Alcatel 2063 that has a strange paint job.  I found repair parts for it and now can open it up and find out what is what on the inside.  The motor runs fine but the vacuum pump was not making vacuum ( acording to the guy that had it ).  We shall see.  
                 
                Before I can test it i have to power it.  It is a 3 phase motor and I only have single phase so I am thinking that a I have to make a 3-phase converter also.  Just have to find somebody that has done this and survived.  If not, I got a buddy with an industrial building with 3 phase.  I can take it there and run it up. 
                 
                Andrew


                From: VacuumX@yahoogroups.com [mailto:VacuumX@yahoogroups.com] On Behalf Of dean@...
                Sent: Tuesday, February 06, 2007 9:30 PM
                To: VacuumX@yahoogroups.com
                Subject: Re: [VacuumX] The vacuum tank known as

                For a while Varian resold Alcatel vacuum pumps that look just like the one in your picture. The Varian pumps were SD-xx series, where the x refered to the model number or capacity.  Varian pumps had a tan paint on the pump and black or brown motors.  Alcatel pumps almost always had orange or black paint on the pump body. Alcatel parts will work for you, but I cannot identify the specific model from the picture.
                 
                Dean
                 
                 
                 
                -----Original Message-----
                From: Aurigema, Andrew N. \(KSC\)[ASRC AEROSPACE] [mailto:andrew. n.aurigema@ nasa.gov]
                Sent: Tuesday, February 6, 2007 04:50 AM
                To: VacuumX@yahoogroups .com
                Subject: RE: [VacuumX] The vacuum tank known as " baby George"

                Hi Gang.
                 
                The (new to me) baby vacuum chamber is now located at my hanger.  It was a fun weekend moving that thing a few hundred miles but nobody got killed and nothing important got broke.
                 
                 
                Now I just have to make it hold vacuum.  James and I are thinking of making a vac/melting oven out of it so we can make mirrors from scratch.  
                 
                Oh,  can anybody identify this pump ??? http://ph.groups. yahoo.com/ group/VacuumX/ photos/view/ bd69?b=3 
                 
                It has a 3 hp motor on it but no identifiers on the vac pump section.  I am going to take it apart and wanted to get a rebuild kit for it.  Any help would be appriciated.
                 
                Andrew


                From: VacuumX@yahoogroups .com [mailto:VacuumX@ yahoogroups. com] On Behalf Of James Lerch
                Sent: Friday, January 26, 2007 4:09 PM
                To: VacuumX@yahoogroups .com
                Subject: [VacuumX] The vacuum tank known as "George"

                OH BOY...

                Andrew purchased a vacuum tank, and WOW what a vacuum tank.  Words can't adequately describe the dimensions involved, but I think it is safe to say his itty bitty Welch 1397 17cfm (500L/min) pump ain't gonna cut the mustard :-0

                http://lerch. no-ip.com/ atm/Projects/ Drew_tank/

                So, I'm thinking he's going to need 2 or 3x 1397 pumps in parallel, all being fed by roots type blower to get the CFM up?  Then, where do you find a 20" diameter diffusion pump?  Is there a practical limit for the number of diffusion pumps that can be paralleled?

                Since Drew is looking to coat 40inch mirrors, I'm thinking the first thing we need to do is break out the plasma cutter and knock 4 or 5 feet off the length of that chamber!

                Like I said, OH BOY.

                -- 
                Take Care,
                James Lerch
                http://lerch. no-ip.com/ atm (My telescope construction, testing, and coating site)
                http://lerch. no-ip.com/ ChangFa_Gen (My 15KW generator project)
                
                "Anything that can happen, will happen" -Stephen Pollock from:
                "Particle Physics for Non-Physicists: A Tour of the Microcosmos"
                
                " Press on: nothing in the world can take the place of perseverance.
                Talent will not; nothing is more common than unsuccessful men with talent.
                Genius will not; unrewarded genius is almost a proverb.
                Education will not; the world is full of educated derelicts.
                Persistence and determination alone are omnipotent. " 

              • Anderson, Gordon (Hovensa)
                Some Variable frequency drives will convert single phase to three phase. Though it might be cheaper to get the power company to hook you up. Gordon ... From:
                Message 7 of 15 , Feb 7, 2007
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                  Message
                  Some Variable frequency drives will convert single phase to three phase.  Though it might be cheaper to get the power company to hook you up. 
                   
                   
                   
                  Gordon
                   
                   
                  -----Original Message-----
                  From: VacuumX@yahoogroups.com [mailto:VacuumX@yahoogroups.com] On Behalf Of Aurigema, Andrew N. (KSC)[ASRC AEROSPACE]
                  Sent: Wednesday, February 07, 2007 10:08 AM
                  To: VacuumX@yahoogroups.com
                  Subject: RE: [VacuumX] The vacuum tank known as baby George

                  Dean,
                   
                  Thanks. 
                   
                  With that info I was able to determine that the pump is a Alcatel 2063 that has a strange paint job.  I found repair parts for it and now can open it up and find out what is what on the inside.  The motor runs fine but the vacuum pump was not making vacuum ( acording to the guy that had it ).  We shall see.  
                   
                  Before I can test it i have to power it.  It is a 3 phase motor and I only have single phase so I am thinking that a I have to make a 3-phase converter also.  Just have to find somebody that has done this and survived.  If not, I got a buddy with an industrial building with 3 phase.  I can take it there and run it up. 
                   
                  Andrew


                  From: VacuumX@yahoogroups .com [mailto:VacuumX@ yahoogroups. com] On Behalf Of dean@electricmist. com
                  Sent: Tuesday, February 06, 2007 9:30 PM
                  To: VacuumX@yahoogroups .com
                  Subject: Re: [VacuumX] The vacuum tank known as

                  For a while Varian resold Alcatel vacuum pumps that look just like the one in your picture. The Varian pumps were SD-xx series, where the x refered to the model number or capacity.  Varian pumps had a tan paint on the pump and black or brown motors.  Alcatel pumps almost always had orange or black paint on the pump body. Alcatel parts will work for you, but I cannot identify the specific model from the picture.
                   
                  Dean
                   
                   
                   
                  -----Original Message-----
                  From: Aurigema, Andrew N. \(KSC\)[ASRC AEROSPACE] [mailto:andrew. n.aurigema@ nasa.gov]
                  Sent: Tuesday, February 6, 2007 04:50 AM
                  To: VacuumX@yahoogroups .com
                  Subject: RE: [VacuumX] The vacuum tank known as " baby George"

                  Hi Gang.
                   
                  The (new to me) baby vacuum chamber is now located at my hanger.  It was a fun weekend moving that thing a few hundred miles but nobody got killed and nothing important got broke.
                   
                   
                  Now I just have to make it hold vacuum.  James and I are thinking of making a vac/melting oven out of it so we can make mirrors from scratch.  
                   
                  Oh,  can anybody identify this pump ??? http://ph.groups. yahoo.com/ group/VacuumX/ photos/view/ bd69?b=3 
                   
                  It has a 3 hp motor on it but no identifiers on the vac pump section.  I am going to take it apart and wanted to get a rebuild kit for it.  Any help would be appriciated.
                   
                  Andrew


                  From: VacuumX@yahoogroups .com [mailto:VacuumX@ yahoogroups. com] On Behalf Of James Lerch
                  Sent: Friday, January 26, 2007 4:09 PM
                  To: VacuumX@yahoogroups .com
                  Subject: [VacuumX] The vacuum tank known as "George"

                  OH BOY...

                  Andrew purchased a vacuum tank, and WOW what a vacuum tank.  Words can't adequately describe the dimensions involved, but I think it is safe to say his itty bitty Welch 1397 17cfm (500L/min) pump ain't gonna cut the mustard :-0

                  http://lerch. no-ip.com/ atm/Projects/ Drew_tank/

                  So, I'm thinking he's going to need 2 or 3x 1397 pumps in parallel, all being fed by roots type blower to get the CFM up?  Then, where do you find a 20" diameter diffusion pump?  Is there a practical limit for the number of diffusion pumps that can be paralleled?

                  Since Drew is looking to coat 40inch mirrors, I'm thinking the first thing we need to do is break out the plasma cutter and knock 4 or 5 feet off the length of that chamber!

                  Like I said, OH BOY.

                  -- 
                  Take Care,
                  James Lerch
                  http://lerch. no-ip.com/ atm (My telescope construction, testing, and coating site)
                  http://lerch. no-ip.com/ ChangFa_Gen (My 15KW generator project)
                  
                  "Anything that can happen, will happen" -Stephen Pollock from:
                  "Particle Physics for Non-Physicists: A Tour of the Microcosmos"
                  
                  " Press on: nothing in the world can take the place of perseverance.
                  Talent will not; nothing is more common than unsuccessful men with talent.
                  Genius will not; unrewarded genius is almost a proverb.
                  Education will not; the world is full of educated derelicts.
                  Persistence and determination alone are omnipotent. " 

                • Darald Bantel
                  ... snip Just to give some perspective. Got a quote last summer on getting a three phase service outside Edmonton AB Canada. Well it was minimum $70k and then
                  Message 8 of 15 , Feb 7, 2007
                  • 0 Attachment
                    On Wed, 2007-02-07 at 12:09 -0400, Anderson, Gordon (Hovensa) wrote:
                    > Some Variable frequency drives will convert single phase to three
                    > phase. Though it might be cheaper to get the power company to hook
                    > you up.

                    snip

                    Just to give some perspective. Got a quote last summer on getting a
                    three phase service outside Edmonton AB Canada. Well it was minimum $70k
                    and then the power services after (and they are definitely NOT cheap!).
                    This really made me look at getting off-grid and making my own power!

                    Darald
                  • Jim RabidWolf
                    Andrew - you ll probably find the puppy suffers from the same problem my Savant VP100 did - it was left full of oil and just sat in a closet for 10 years. I
                    Message 9 of 15 , Feb 7, 2007
                    • 0 Attachment
                      Andrew - you'll probably find the puppy suffers from the same problem my Savant VP100 did - it was left full of oil and just sat in a closet for 10 years. I ended up stripping and completely rebuilding due to the rust (got the kit from Precision - everything but the vanes, the just needed a slight touchup where they were rusted to the bores). The bores of both stages had very tiny pits in them - I cured that with a brake hone, using medium, then fine stones (I know you're not supposed to do that, but I did), I then ran the living snot of out the pump until the vanes eventually polished them glass smooth, I tried a number of other ways, but cheap vacuum oil (I can get yellow jacket wholesale for about $14USD AFAIR) - eventually, it began to pull a vacuum, got better every time I ran it pulled harder and harder. Now, it pulls a 6x10 inch bell jar down to 2.5x10^-4 in just about 15 minutes take about 40 for my 10x18.
                       
                      Unless the bore is severly pitted, you should be able to rebuild without a lot of problems. If it is badly pitted, not all hope is lost - if you know someone with a mill and a boring head, provided they are a relatively competent machinist, they can bore it out for you. Given that most vanes have better tha .75 inches of "slack" to them - that's how much is riding inside the shaft - you can take quite a bit off and still not have problems. Worst case, I can bore it out and you can hand finish it (I did mine in the mill, but a drill press will work and HF sells one that'll do the job for $40USD - or you can build a frame for a hand drill to do it).
                       
                      If you bore it out, you actually pick up extra benefit in the form of vacuum - you have a large bore and your're going to up the flow thru.
                       
                      If the backing plate for the pump is slightly pitted - us a piece of plate glass with a sheet of finer and finer grades of wet/dry emery and hand lap it out.
                       
                      So - there's a quick run down - who knows - you might find the seals a good and it's just gooped up and needs a good cleaning (there was an inch of oil/water sludge in the bottom of my oil box - that should give you an idea.
                       
                      Anytime a pump sits for a while, it need to be run til it's warmed up to drive the moisture out - and it should NEVER be left open with oil in it (and never just left open) - never leave it sitting too long without running it.
                       
                      Let me know if I can help. (I have a full machine and electronics shop) - that goes for the rest of the group - if you need something - yell... barter is my life.
                       
                      Rabid
                       
                      ----- Original Message -----
                      Sent: Wednesday, February 07, 2007 8:07 AM
                      Subject: RE: [VacuumX] The vacuum tank known as baby George

                      Dean,
                       
                      Thanks. 
                       
                      With that info I was able to determine that the pump is a Alcatel 2063 that has a strange paint job.  I found repair parts for it and now can open it up and find out what is what on the inside.  The motor runs fine but the vacuum pump was not making vacuum ( acording to the guy that had it ).  We shall see.  
                       
                      Before I can test it i have to power it.  It is a 3 phase motor and I only have single phase so I am thinking that a I have to make a 3-phase converter also.  Just have to find somebody that has done this and survived.  If not, I got a buddy with an industrial building with 3 phase.  I can take it there and run it up. 
                       
                      Andrew


                      From: VacuumX@yahoogroups.com [mailto:VacuumX@yahoogroups.com] On Behalf Of dean@...
                      Sent: Tuesday, February 06, 2007 9:30 PM
                      To: VacuumX@yahoogroups.com
                      Subject: Re: [VacuumX] The vacuum tank known as

                      For a while Varian resold Alcatel vacuum pumps that look just like the one in your picture. The Varian pumps were SD-xx series, where the x refered to the model number or capacity.  Varian pumps had a tan paint on the pump and black or brown motors.  Alcatel pumps almost always had orange or black paint on the pump body. Alcatel parts will work for you, but I cannot identify the specific model from the picture.
                       
                      Dean
                       
                       
                       
                      -----Original Message-----
                      From: Aurigema, Andrew N. \(KSC\)[ASRC AEROSPACE] [mailto:andrew. n.aurigema@ nasa.gov]
                      Sent: Tuesday, February 6, 2007 04:50 AM
                      To: VacuumX@yahoogroups .com
                      Subject: RE: [VacuumX] The vacuum tank known as " baby George"

                      Hi Gang.
                       
                      The (new to me) baby vacuum chamber is now located at my hanger.  It was a fun weekend moving that thing a few hundred miles but nobody got killed and nothing important got broke.
                       
                       
                      Now I just have to make it hold vacuum.  James and I are thinking of making a vac/melting oven out of it so we can make mirrors from scratch.  
                       
                      Oh,  can anybody identify this pump ??? http://ph.groups. yahoo.com/ group/VacuumX/ photos/view/ bd69?b=3 
                       
                      It has a 3 hp motor on it but no identifiers on the vac pump section.  I am going to take it apart and wanted to get a rebuild kit for it.  Any help would be appriciated.
                       
                      Andrew


                      From: VacuumX@yahoogroups .com [mailto:VacuumX@ yahoogroups. com] On Behalf Of James Lerch
                      Sent: Friday, January 26, 2007 4:09 PM
                      To: VacuumX@yahoogroups .com
                      Subject: [VacuumX] The vacuum tank known as "George"

                      OH BOY...

                      Andrew purchased a vacuum tank, and WOW what a vacuum tank.  Words can't adequately describe the dimensions involved, but I think it is safe to say his itty bitty Welch 1397 17cfm (500L/min) pump ain't gonna cut the mustard :-0

                      http://lerch. no-ip.com/ atm/Projects/ Drew_tank/

                      So, I'm thinking he's going to need 2 or 3x 1397 pumps in parallel, all being fed by roots type blower to get the CFM up?  Then, where do you find a 20" diameter diffusion pump?  Is there a practical limit for the number of diffusion pumps that can be paralleled?

                      Since Drew is looking to coat 40inch mirrors, I'm thinking the first thing we need to do is break out the plasma cutter and knock 4 or 5 feet off the length of that chamber!

                      Like I said, OH BOY.

                      -- 
                      Take Care,
                      James Lerch
                      http://lerch. no-ip.com/ atm (My telescope construction, testing, and coating site)
                      http://lerch. no-ip.com/ ChangFa_Gen (My 15KW generator project)
                      
                      "Anything that can happen, will happen" -Stephen Pollock from:
                      "Particle Physics for Non-Physicists: A Tour of the Microcosmos"
                      
                      " Press on: nothing in the world can take the place of perseverance.
                      Talent will not; nothing is more common than unsuccessful men with talent.
                      Genius will not; unrewarded genius is almost a proverb.
                      Education will not; the world is full of educated derelicts.
                      Persistence and determination alone are omnipotent. " 

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