Reports until 12:11, Tuesday 27 March 2018
LHO VE
chandra.romel@LIGO.ORG - posted 12:11, Tuesday 27 March 2018 - last comment - 17:03, Wednesday 28 March 2018(41163)
assembled first LHO IP chevron baffle

Stephen A., Chandra R.

This morning Stephen helped/instructed me on assembly of the first LHO chevron baffle. Baffle SN 001 was installed in nipple housing SN 001. We iterated several times on bending the louvers to securely set them in place and ended with an N2 "top gun" blow off before bolting the two baffle halves together and fastening to the nipple housing. The eight bolts that secure the baffle to the housing still need to be torqued. We placed the two 16.5" Cu gaskets on knife edges and wrapped with Al foil for temporary storage in VPW until we can install on IP11 at EY later this week. Stephen will post pictures later.

Refer to LLO aLOG for more detail on steps of installation. https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=38375

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stephen.appert@LIGO.ORG - 17:03, Wednesday 28 March 2018 (41179)
Link

Assembly procedure is E1800067 (still needs updates based on lessons learned in assembly work at LLO and LHO). One key feature of this assembly effort - we only had 2 people, so we took the following approach to placing the D1600409 louver cell within the D1600410 nipple:

  • We left the nipple resting on the table and (leaving enough room for a person's hand to support some of the weight of the louver cell) gently lowered the louver cell into the nipple.
    • rather than using one person to hold the nipple with central axis horizontal as previously done at LLO
  • The nipple mounting ring/retainer was underneath the louver cell, meaning the bolts were added by a person from underneath
  • The clocking was a little tricky (could be improved using class B 8-32 set screws) but manageable, with one person sighting from underneath
  • This procedure felt relatively safe and stable, and also seemed more efficient. This will be adopted as the preferred approach, as it is quicker, just as reliable, and more stable than holding the nipple horizontal.

This assembly that we built is on ICS as ASSY-D1600431-001

I have attached photos of various stages - see below descriptions:

  • IMG_4785 - one louver article noticed with small reflective specs visible in coating, not noticed previously. No particulate from wiping, so no defect record and this louver was used.
  • IMG_4788 - one half louver cell before tune-up. No obvious particulate visible. Time to tune up!
  • IMG_4791 - after a chattering louver is identified, the louver is removed and the slot is used as a forming surface. This sub-procedure is known as tuning up the louver.
  • IMG_4792 - pressure setting of THIS top gun for THIS application, before pulling the trigger. Actual flow comes at ~10% lower pressure. Note that top gun flow rate is dependent on a range of parameters, including input pressure, plumbing geometry, etc.
  • IMG_4793 - top gun setup used
  • IMG_4794 - Fully assembled Unit ASSY-D1600431-001, with copper CF gaskets in place to protect knife edge.
  • IMG_4796 - Foil used to retain copper CF gasket and protect assembly from particulate
  • IMG_4799 - Work completed for the day
Images attached to this comment