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groups:mg:experiment:vacuum [2018/08/13 12:40] – [How to evacuate the vacuum chamber] wfriesengroups:mg:experiment:vacuum [2018/11/01 10:25] (current) – [Oil change of the pre-vacuum pump] fim
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   * Beforeyou close the vaccum chamber, disconnect the protective gas and the cable of the vent valve, to avoid overpressure in the chamber.   * Beforeyou close the vaccum chamber, disconnect the protective gas and the cable of the vent valve, to avoid overpressure in the chamber.
   * Chack if all Viewports are assembled.   * Chack if all Viewports are assembled.
-  * Open (only!) the pneumatic magnetic valve of the small Turbo pump. Disconnect the plug for the pneumatic magnetic valve of the big turbo pump at the power extension board, which is located on top of the flowbox.+  * Open (only!) the pneumatic magnetic valve of the small Turbo pump. Disconnect the plug for the pneumatic magnetic valve of the big turbo pump at the power extension board, which is located on top of the flowbox. After doing so plug in the yellow plug near the door and press 'reset'.
   * Gently open the yellow hand valve at the small Turbo pump. This will pump down the chamber to the pre-vacuum level. Opening the valve will worse the pre-vacuum. Don't let the needle hit the end of the scale at the measuring device for the pre-vacuum.   * Gently open the yellow hand valve at the small Turbo pump. This will pump down the chamber to the pre-vacuum level. Opening the valve will worse the pre-vacuum. Don't let the needle hit the end of the scale at the measuring device for the pre-vacuum.
   * Wait until the pre-vacuum reach <10^1 mbar.   * Wait until the pre-vacuum reach <10^1 mbar.
   * Open the pneumatic magnetic valve at the big Turbo pump.   * Open the pneumatic magnetic valve at the big Turbo pump.
   * Turn on both Turbo pumps and wait untill both have reached nominal speed.   * Turn on both Turbo pumps and wait untill both have reached nominal speed.
-  * Open the valve under the table at the big Turbo pump.+  * Open the valve under the table of the big Turbo pump by connecting the plug at the power extension board.
   * Switch on the cold-cathod measuring device when the pressure in the main chamber is below 10^-3 mbar.   * Switch on the cold-cathod measuring device when the pressure in the main chamber is below 10^-3 mbar.
   * Turn on the IGP when the pressure has reached 10^-6 mbar. Initially this will cause the pressure to rise again.   * Turn on the IGP when the pressure has reached 10^-6 mbar. Initially this will cause the pressure to rise again.
 +
 +===== How to refill magnesium in the oven =====
 +  * For opening the oven, at least two people are required.
 +  * The Oven is attached to the chamber with a CF 63 flange. So keep a fresh CF63 copper gasket ready for replacement.
 +  * Pump down the vacuuum chamber following the same procedure as above.
 +  * Open the CF 63 flange connecting oven to the vacuum chamber.
 +  * Oven is extended lengthwise into the vacuum chamber. Gently pull out the tube without hitting the walls of the chamber.
 +  * The oven nozzle is connected in the end of the tube with a nut. Open this nut to take out the nozzle.
 +  * Clean the nozzle as well as the inside of the oven with acetone. Make sure that acetone is fresh and does not contain any water. 
 +  * Also clean any other tools (spoons etc) that you will use to pour magnesium flakes into the oven.
 +  * Now fill the oven to the top and again fix back the nut with the nozzle on it.
 +  * Reconnect the oven flange to the vacuum chamber with a fresh copper gasket. Make sure that the vent gas is turned off before fixing the screws to avoid overpressure in the chamber.
 +
 +{{:groups:mg:experiment:oven_1.jpg?400 |}} {{:groups:mg:experiment:oven_2.jpg?400 |}} {{:groups:mg:experiment:oven_nozzle.jpg?400 |}}
 +
  
 ===== Heating the pumps (usefull for low 10^-9 pressures and below and after opening the vacuum) ===== ===== Heating the pumps (usefull for low 10^-9 pressures and below and after opening the vacuum) =====
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 *Turbomolekularpumpe TMU 260: {{:groups:mg:experiment:turbopump_tmh_tmu_260a.pdf|}}  *Turbomolekularpumpe TMU 260: {{:groups:mg:experiment:turbopump_tmh_tmu_260a.pdf|}} 
 #*In Betrieb seit XY #*In Betrieb seit XY
 +
 +
 +
 +====== Oil change of the pre-vacuum pump ======
 +
 +The oil has to be changed **every third year** approximately. 
 +
 +  -  First, close the big yellow vent at the source chamber. Second, close the pneumatik vents via the knob at the orange power outlet (close to the door) and check if both are really closed. 
 +  -  CLose the black vent of the pump which is placed close to the on/off switch. 
 +  -  Open the drain screw (No. 8 in manul) labed as "Ablaßschraube"  in order to let the oil out. Than close the screw, let the pump run for 10 sec and open it again in order to let out the remainings. You can refill the oil **Pfeiffer Oil P3** when opening the screw no. 6 until you reach a max level at the inspection window. 
 +  -  Open the vents once the preassure at the pump is the same as at the source chamber.
 +
 +Manual: {{ :groups:mg:experiment:pk115bn_part1.pdf |}}
 +
 +Last changes: nov 2018
 +