We tested the air amplifiers by actuating the beam blockers and profile monitors on the T1 and T2 target stations.
The blockers and profile monitors were each actuated (brought up/out and down/in fully) > 5 times and vacuum remained stable throughout (see attached).
The cycle rate of the air amplifiers (time between 'puffs') under steady conditions (target devices kept in the out position) was measured to be between 60-90 seconds, with 90 seconds corresponding to when the 'flow control' ball valve is fully shut and ~60 seconds when the valve is opened (either partly or fully).
When a target device is brought up, a cycle event will occur shortly after the device reaches the out position.
This cycle time is much longer than last reported in 2014 (see elog #119), by a factor of 2-3.
The top amplifier sounds different from the bottom amplifier (cycles between being 'rattly' and 'quite' between cycles).
Seeing how the beam blockers and profile monitors were actuated smoothly with the air amplifiers, we will keep the system running off the lower air amplifier with the 'flow control' ball valve kept open (not shown).
At some point we will look into disassembling the top amplifier to see why it sounds differently between cycle events.
For reference, both amplifiers read 20psi at the regulator and 120 psi to the target station. |