{"id":606,"date":"2015-02-21T07:36:41","date_gmt":"2015-02-21T15:36:41","guid":{"rendered":"http:\/\/www.rbdinstruments.com\/blog\/?p=606"},"modified":"2024-10-14T11:37:25","modified_gmt":"2024-10-14T18:37:25","slug":"tnbx-ion-pump","status":"publish","type":"post","link":"https:\/\/www.rbdinstruments.com\/blog\/tnbx-ion-pump\/","title":{"rendered":"Servicing a P-E TNBX Ion Pump Well"},"content":{"rendered":"

RBD Instruments provides all of the parts that you need to rebuild these TNBX ion pump wells.\u00a0 Contact us for more information<\/a>.\u00a0 For best results, read this entire post and then look at the pictures at the bottom of the post.<\/p>\n

The P-E (Perkin Elmer) TNBX style of Ion Pump well is found on most of the older PHI AES and ESCA systems. It is 12 inches in diameter and houses 8 ion pump elements. There is also a poppet valve that allows you to isolate the ion pump elements, keeping them under vacuum while venting the upper part of the chamber for maintenance. In this blog post we will show you how to access the ion pump elements for replacement or rebuild. The process includes instructions for disassembling and removing the poppet valve assembly, and removing all shielding and the TSP flange.<\/p>\n

Important: Read through all procedures before beginning work to ensure you have the necessary equipment, personnel, and tools to complete the process.<\/b><\/p>\n

Step 1: Remove the upper half of the chamber.<\/b><\/p>\n

Equipment required: Chain hoist or engine hoist<\/b><\/p>\n

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  1. Turn off all controls and allow the ion gauge filament and the ion pump elements time to cool down.<\/li>\n
  2. While the ion pump elements cool, remove all cables from the system.<\/li>\n
  3. Prepare a space large enough to for the top half of the chamber. We recommend a piece of cardboard on the floor covered with UHV grade foil<\/a>.<\/li>\n
  4. Vent the chamber completely.<\/li>\n
  5. Move the equipment you are going to use to remove the top of half of the system safely so that it\u2019s within range of the chamber. We often use the chain hoist that we have at RBD Instruments. An engine hoist has proven to be a suitable alternative. Additional personnel may be helpful.<\/li>\n
  6. Connect the chains from the equipment to the eyelets on the chamber and remove all bolts that hold the two halves together.<\/li>\n
  7. Use the equipment to remove the upper half of the chamber. Additional personnel may be helpful to help guide the upper half of the chamber away from the bottom half.<\/li>\n
  8. Place the upper half of the chamber in the space you created earlier. It will remain there while you are working on the pumps.<\/li>\n<\/ol>\n

    Step 2: Remove the Poppet valve to access the shielding.<\/b><\/p>\n

    Tools required: Two 7\/16\u201d wrenches.<\/b><\/p>\n

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    1. You should be able to look down into the chamber and see the poppet valve. You will likely see that the ion gauge that protrudes into the chamber above the poppet valve.<\/li>\n
    2. Remove the ion gauge so that you do not damage it while you working inside of the pump well.<\/li>\n
    3. Turn the poppet crank so that the poppet valve is all the way up.<\/li>\n
    4. Grab hold of the poppet valve and rotate it counter-clockwise to unscrew it from the scissor jack.<\/li>\n
    5. Rotate the poppet crank handle <\/b>all of the way counter-clockwise. This crank handle is located on the side of the ion pump well.<\/li>\n
    6. Remove the bolts that mount the poppet crank handle to the flange and rotate the crank handle and the crank housing together, counter-clockwise, until you can remove it from the scissor jack.<\/li>\n
    7. Using two 7\/16\u201d wrenches, loosen and remove the mounting hardware for the scissor jack.<\/li>\n
    8. With the mounting hardware out and the scissor jack free, work the scissor jack out of the ion pump well. This may take some maneuvering, but it will come out.<\/li>\n<\/ol>\n

      Step 3: Remove the TSP (Titanium Sublimation Pump) assembly and lower shielding.<\/b><\/p>\n

      Tools required: <\/b>#1 flat head screw driver, #1 Phillip\u2019s screw driver; 11\/32, 3\/8, 5\/16 and \u00bc wrenches. <\/b><\/p>\n

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      1. Remove the TSP cable from the TSP flange. If you\u2019re lucky there is a screw-on connector for removing the TSP cable. The less convenient version has cap-head screws that fasten the wires to the flange feedthru\u2019s. If you need to remove the wires, make sure that you mark the center \u201ccommon\u201d wire. <\/b>This is the only wire that has a specific post that it must go to.<\/li>\n
      2. With the wires removed you can now safely remove the TSP assembly.<\/li>\n
      3. Remove the first piece of shielding. It is the shield that blocks titanium from the upper chamber and the poppet valve. The shielding is removed by loosening the mounting hardware. All shields and mounting hardware should be stored on a clean surface.<\/li>\n
      4. Remove the circular cryo shield. This comes apart in sections for easier removal.<\/li>\n
      5. You can now reach the high voltage conductor that runs from the high voltage feedthru to each of the ion pump elements.<\/li>\n<\/ol>\n

        Step 4: Ion Pump Element removal.<\/b><\/p>\n

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        1. Remove the high voltage conductor. It can either be one solid piece of ribbon or it can come in sections that can be removed one at a time. This conductor can be attached using a variety of different hardware, so be prepared with a variety of screw drivers and wrenches.<\/li>\n
        2. Remove all of the ion pump elements once you\u2019ve removed the high voltage conductor.<\/li>\n
        3. We recommend that you remove the high voltage feedthru flange for inspection. It can sometimes get coated, and you also may find titanium flakes have worked their way up inside the flange. Once everything is removed and out of the way, you can clean the ion pump well.<\/li>\n<\/ol>\n

          Step 5: Cleaning and replacement of ion pump well and associated parts.<\/b><\/p>\n

          Equipment and tools required: Wire brush, shop vacuum<\/b><\/p>\n

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          1. Brush the walls, nooks, and crannies of the ion pump well to remove any build up titanium flakes.<\/li>\n
          2. Vacuum out the ion pump well with a shop vacuum. Wrap the end of the hose in foil to prevent smearing the plastic hose with whatever might be on the ion pump well walls. It also prevents transferring whatever might be on the hose onto the walls of the ion pump well.<\/li>\n
          3. Use isopropanol and Kim wipes to clean the inside of the ion pump well.<\/li>\n
          4. Install the newly rebuilt or brand new ion pumps.<\/li>\n
          5. Vacuum out the high voltage feedthru. If it\u2019s obviously coated with titanium you will want to clean off the titanium using a sand blaster or some form of chemical etching process to prevent leakage current to ground.<\/li>\n
          6. For the TSP assembly, RBD Instruments sells a variety of products to rebuild this assembly or you can even buy a complete assembly with or without exchange.<\/li>\n
          7. Clean the shields using the above process described for cleaning the ion pump well (using the wire brush, vacuum, and isopropanol).<\/li>\n
          8. Change the ion gauge filament, or if it\u2019s in bad condition, replace the entire ion gauge. Keep in mind that RBD Instruments, Inc. sells ion gauge filaments and brand new assemblies as well.<\/li>\n<\/ol>\n

            Step 6: Reassembly <\/b><\/p>\n

            Tools required: 100 ft\/lbs torque wrench<\/b><\/p>\n

            New parts required: New copper gaskets for all conflate flanges.<\/b><\/p>\n

            Note:\u00a0\u00a0\u00a0 <\/b>You can get the TNBX gasket here –<\/p>\n

            For Bolt Type Wire Seal Flanges, the wire diameter is 0.080\u201d.<\/span><\/span><\/div>\n
            \u00a0<\/span><\/span><\/div>\n
            The smallest diameter we offer is Thermionics WSG Model #GW-140 (bolt type), ~12.962\u201d I.D. <\/span><\/span><\/div>\n
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            <\/div>\n
            3118 Depot Road, Hayward, CA 94545<\/span><\/span><\/div>\n
            thermionics.com<\/span><\/a> | <\/span>tmpi.us\u00a0<\/span><\/a><\/span><\/div>\n