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Equipment/High Vacuum Station: Difference between revisions

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Equipment/High Vacuum Station (view source)

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==Proposed Uses==
==Proposed Uses==


* Resin degassing (backing pump ONLY - separate degassing chamber)
* Creating x-ray sources, CRTs & other electron-beam experiments
* Creating x-ray sources, CRTs & other electron-beam experiments
* Vacuum glasswork (EG; thermionic valve making/repair)
* Vacuum glasswork (EG; thermionic valve making/repair)
* Surface coatings (optical coatings, photocathodes, metalic finishes, titanium oxide coatings)
* Surface coatings (optical coatings, photocathodes, metalic finishes, titanium oxide coatings)
* Electron microscopy
* Electron microscopy
* Outer-space environment test chamber


==Design concept==
==Design concept==


To enable all the uses people are interested in, the system needs to have vacuum access at a number of stages in the pumping system.
To create an ultra-high vacuum source capable of being purposed to a wide range of high-vacuum related tasks.
 
* Combining a resin degassing chamber/line into the design has now been abandoned as there are enough lower-spec rotary pumps available now to build a dedicated station for that purpose.


===Backing/roughing pump===
===Backing/roughing pump===


The backing pump is a rotary pump that should be capable of reaching near 0mbar. On a double valve setup one pump should be able to act as backing pump to the diffusion pump or to directly pump a separate degassing chamber. This should allow the degassing to be used without the worry of contaminating the ultraclean conditions of the High-Vacuum chamber or diffusion pump.
The backing pump is a rotary pump that should be capable of meeting or exceeding the backing pressure and maximum output of the diffusion pump.
 
There is a pledge for a suitable pump, as none offered so far have sufficient ultimate pressure and/or pumping speed.
http://wiki.london.hackspace.org.uk/view/Pledges/Vacuum_Pump
 
===Degassing chamber===
 
The initial chamber is a home-made one made by Sci from an old fire extinguisher and water fittings.
 
Degassing resins allows small air bubbles to expand under low pressure and burst, removing the gas from the liquid. In plain resins this leads to stronger smoother castings, and with filler powders it creates a stronger bond between filler and resin.


As resins can bubble quite a lot in degassing, the vacuum line on the chamber should have a catch-pot fitted for safety. This is an empty vacuum-sealed container with two connections at the top. Any spilt resin or spray that makes its way down the initial vacuum line will be caught in this "dog-leg" and prevented from contaminating or damaging the rotary pump.
<del>There is a pledge for a suitable pump, as none offered so far have sufficient ultimate pressure and/or pumping speed.
http://wiki.london.hackspace.org.uk/view/Pledges/Vacuum_Pump</del> The pledge was successful and a backing pump has been aquired.


If you want to watch marshmallows expand, this is the portion of the system you'll be using.


===Diffusion pump===
===Diffusion pump===
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