Difference: MWardWorkDiary2017Log1 (21 vs. 22)

Revision 2217 Jan 2018 - MarkWard

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META TOPICPARENT name="MarkWard"
-- Public.MarkWard - 27 Sep 2017

Previous Logbook

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17-01-2018

  • Lots of investigation into vessel leaks, investigations done/tests
    • Gas system control testing - Few features/issues/reported to Patrick
      • Valve opening/closing sequences - there are occations where valve changes are made simultaniously, which can be risky for the pump. It is taken care of a little due to volume exchange and that the gas board and lines are lower volume than the cavity infront of the pump. BUT it should be changed such that the pump is isolated for a few moments before other gas board changes are made
      • During pressure changes it appears that the inlet valve for our nitrogen is not being isolated. The vessel is being isolated as expected, but that valve (V3) remains open. Made people aware and to isolate it at the end of pressure changing operations
      • Pressure request is performed in BarA, yet the monitor point is the Relative Gauge, - This has been indicated better on the page now
      • Relative gauge bottoms out at about 0.7 BarA, thus if using adjust pressure to pull vacuum in steps doesn't work as intended. There is no auto switch to the vacuum gauge yet
      • If the vessel is already at some vacuum, the evacuuate vessel appears to not work, it will claim the vessel is already pumped down.
    • Leak Tests
      • Wika gauge unmounted and inspected. It is using a BSPP (British Standard Piping Parallel) adapter that has been welded into a KF flange. The issue is the depth of the fitting used is too shallow for the gauge. It means the seal was being made with lots of teflon (BSPP is not an interference fitting) and mashing the face of the gauge against the adapter end. The actual way would be to use the pre-installed face sealing o-ring on the gauge.
      • Adapted the Wika gauge to seal better via a two face seal gaskets (tip and body) and teflon.
      • Performed bubble tests (see Adriana for pictures) on the burst disks, found leaks
      • Added teflon as a soft seal against the burst disk and the holder. We should concider buying some teflon rings or a sheet of teflon and a punch kit to make some gaskets for use in this purpose.
      • Main flange silicone seal appears to be slowly flowing and rupturing under the compression. I have requested info from Sam, investigating suppliers of gasket cord, We can get Nitrile o-ring material from a university supplier (along with splicing tools) without issue, I am trying to find a supplier that will do different profile cord as the seal we have is square profile.
      • www.polymax.co.uk - Do a range of different material including silicone, though only have square section in Nitrile.
      • http://www.barnwell.co.uk - claim they can do anything... (involving seals)
      • http://www.par-group.co.uk/ - Have a good amount of choice in materials and cross sections
    • Result is that vessel appears to be holding pressure, and is tracking tempterature. (again see Adrianas page)
  • Camera Mounts - Assisting Adriana and searing for bolts etc
    • We have an issue that cryovac supplied camera mounts held together using threaded rod and welded nuts
    • Without making any modifications, we have to find someone to supply us with 110mm M4 bolts, not exactly a standard size
    • http://www.ashheat.co.uk can custom fabricate bolts - Spoke with them, they seem well setup to do that
    • The other option (and to make it more like DMTPC) is to tap and counter sink the holes at the camera mount such that only the hat part needs removal for camera adjustment.
    • Leaving it as it is means any adjustments to the camera are a 2/3 person job due to the weight, and risk of hitting the quartz while trying to unmount/remount.
    • Need to aquire some 140mm M8 bolts for the quartz windows 10mm longer than current as the camera mount ads more length.
    • Cryovac shipped what looks like a CF flange weld-met with each camera mount... without any apparent use, seems like they took the design of the camera mount and didn't make any modifications to it at all compared to the cad.
    • CameraMount.png
    • The Quartz is not light tight in the design.
  • Parts / Duplication
    • Ordered all parts to make a duplicate power box with extra capacity for our valves
    • Placed order with Ian for another netbooter - need to check status of this.
    • Adding longbolt supplier to university system
    • Ordered hard drive replacement for hpdaq.
 

10-01-2018

  • Vessel preparation for insurance inspection was successful
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META FILEATTACHMENT attachment="CameraMount.png" attr="" comment="" date="1516190342" name="CameraMount.png" path="CameraMount.png" size="289892" user="udap005" version="1"
 
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