The lower amplifier for the T2 target station air supply was removed for teardown, inspection, and rebuild.
The goal of this operation is to understand wear development in the air amplifier over ~13 years of operation, and potentially determine a recommeded service interval.
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The T2 volume was vented for an unrelated maintenance operation during this time.
During testing, prior to removing the lower amplifier, both regulators were set to ~20 psi.
The upper air amplifier resulted in ~125 psi at the outlet while the lower air amplifier resulted in ~120 psi at the outlet.
The upper air amplifier had more audible air flowing out from the muffler than the lower amplifier.
'Scratching' sounds in both amplifiers were comparable.
The following cycle times were recorded with the M20 BB raised/out (min:sec):
UPPER: 1:22 / 1:00 / 2:06
LOWER: 2:30 / 1:46 / 2:12
The following times were recorded to raise the M20 BB (sec):
UPPER: 8.36 / 8.76
LOWER: 8.56 / 9.10
These times will be compared against after completing the teardown and rebuild of the lower amplifier, at which point this ELOG will be updated.
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UPDATE (Feb 23, 2024):
The lower air amplifier was serviced (photos in 'S:\Albert Kong\Shutdown Files\2024\Feb20 T2 Lower Amplifier Cleanup'):
- Full assembly cleaning.
- Piston and barrel was cleaned and lubricated, o-rings and plastic components replaced (with new lubricated ones).
- Pilot valve components replaced (except plug).
- Check valves (4x) cleaned and plastic/rubber components replaced (with new lubricated ones).
- Muffler cleaned (blown out with compressed air).
- Spool and sleeve assembly cleaned, o-rings replaced (with new lubricated ones), and rubber stopper replaced.
- Clamping rods tightened to ~17 ft-lbs.
Note: the piston o-rings were difficult to seat on the piston body/teflon ring. During assembly, we instead seated the o-ring in the barrel on the piston plates (see picture), which allowed the oring to be seated properly, before placing the piston body onto the piston rod.
After servicing, the amplifier was returned to the station, air connections reconnected, and tested.
Note: it is recommended to do torque-ing of the clamping rods as a final step to simplify mounting of the amplilfier and re-doing connections to the rest of the compressed air system.
The first observation we made was how silently the lower amplifier now operates when cycled: only the exhaust sound from the muffler can be heard.
Note that the piston's motion can be heard when listening ~5cm away from the amplifier barrel.
The following times were recorded to raise the M20 BB (sec):
UPPER: ~8.5
LOWER: ~7.7s
The following cycle times were recorded with the M20 BB in the out/raised position (min:sec):
UPPER: 1:05 / 1:04
LOWER: 1.22 / 1:45
The outlet pressure from the amplifier registers 120 psi with the regulator set only to 15 psi (improvement from previous performance as well as the upper air amplifier's performance).
We will check in on the amplifier next week to see if it still operates silently and can actuate the beam blockers/profile monitor without issue, at which point this ELOG will be updated.
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UPDATE (Feb 26, 2024):
The lower amplifier was inspected this morning, higher volume sound could be heard from the drum in concert with the motion of the piston, but still much quieter than before servicing.
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