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VIS (BS)
fabian.arellano - 15:19 Monday 26 October 2020 (15322) Print this report
Buoyancy effect in Type-B suspensions GAS Filters.

When the suspensions are brought back to atmospheric pressure, the bodies are subject to a bouyancy force that moves the GAS Filter keystones upwards. Such displacements are shown below.

  • Venting began on Thursday  22nd of October in the morning.
  • Venting finished on Monday 26th of October just before 12 o'clock.
  • The temperature remained constant throughout the process.

The values below are particularly important for BS and SR3, whose ballast masses will be adjusted soon.

Beam splitter

BS GAS Filter Initial (µm) Final (µm) Buoyancy effect (µm)
F0 122 1374 1,252
F1 356 568 212
BF -7.4 356 363
Temperature 23.6 °C 23.6 °C  

 

SR2 suspension

SR2 GAS Filter Initial (µm) Final (µm) Buoyancy effect (µm)
F0 -1070 -888 182
F1 33 834 801
BF 19 336 317
Temperature 23.8 °C 23.8 °C  

 

SR3 suspension

SR3 GAS Filter Initial (µm) Final (µm) Buoyancy effect (µm)
F0 -799 -511 288
F1 -417 44 461
BF -211 100 311
Temperature 23.3 °C 23.3 °C  

 

SRM suspension

SRM GAS Filter Initial (µm) Final (µm) Buoyancy effect (µm)
F0 -1,596 -1,466 130
F1 -67 349 416
BF 119 454 335
Temperature 23.0 °C 23.0 °C  



 

Comments to this report:
fabian.arellano - 16:47 Wednesday 14 September 2022 (22096) Print this report

The tables below show the values of the buoyancy effect for all the GAS filters in Type-B.

  • For the purposes of comparison, the values measured on the 26th of October 2020 are also shown (klog 15322).
  • The temperature values given are from the ondotori (see Fig. 5).
  • The pressure went from 100,000 to 4.4e-3 Pa (see Fig. 1).

 

Beam splitter

26-10-2020

14-09-2022

BS GAS Filter Initial (µm) Final (µm) Buoyancy effect (µm) Initial (µm) Final (µm) Buoyancy effect (µm)
F0 122 1374 1,252 306 -1,126 1,433
F1 356 568 212 152 -105 258
BF -7.4 356 363 82 -325 407
Temperature 23.6°C 23.6°C   22.8°C 22.9°C  

 

 

SR2 suspension

26-10-2020

14-09-2022

SR2 GAS Filter Initial (µm) Final (µm) Buoyancy effect (µm) Initial (µm) Final (µm) Buoyancy effect (µm)
F0 -1070 -888 182 82 -155 237
F1 33 834 801 576 -188 763
BF 19 336 317 130 -155 285
Temperature 23.8 °C 23.8 °C   23.0°C 23.1°C  

 

 

SR3 suspension

26-10-2020

14-09-2022

SR3 GAS Filter Initial (µm) Final (µm) Buoyancy effect (µm) Initial (µm) Final (µm) Buoyancy effect (µm)
F0 -799 -511 288 -43 -273 230
F1 -417 44 461 724 291 432
BF -211 100 311 447 153 294
Temperature 23.3 °C 23.3 °C   22.6°C 22.6°C  

 

 

SRM suspension

26-10-2020

14-09-2022

SRM GAS Filter Initial (µm) Final (µm) Buoyancy effect (µm) Initial (µm) Final (µm) Buoyancy effect (µm)
F0 -1,596 -1,466 130 97 -40 138
F1 -67 349 416 -22 -368 346
BF 119 454 335 267 -8 275
Temperature 23.0 °C 23.0 °C   22.4°C 22.5°C  

 

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tomotada.akutsu - 23:08 Wednesday 14 September 2022 (22108) Print this report

K1:VAC-PRESSURE_CS_BS seems around 0.2 Pa just now, after a strange "recovery" of the pressure. It had been 4e-3 Pa once... a strange behavior of the vacuum gauge read? Or something relevant incidents happened???

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