Compressed / dry air


  • Dry air must be flushed in the detector SiPM cold boxes and inside the cooling manifold to avoid condensation/frost.
  • According to the specification, the compressed air distributed in the LHC tunnel is good for this application. The dew point is -40 C.
  • An outlet of the compressed air distribution line was installed next to the BGV (Jan 2015)
  • The air distribution chain was installed and put into exploitation in September 2015 (TS2)

Air distribution chain

  • The BGV air distribution system was developed together with EN-CV
  • The layout was designed and the system components were chosen together with Francisco Josa (EN-CV-DOW)
  • The functional specification are given in separate section below


  • All components are from FESTO. The order, made by Francisco, can be seen here
  • Purchase order on EDH:
  • Tubes and fittings
    • Tubes connecting the detector modules to the manifold: PUN-H-6X1-SW from FESTO (OD/ID=6/4 mm), non-transparent (e.g. black)
    • Fittings on the detector modules: QS-6 ("Union QS") from FESTO, used instead of the initially planned NPQP-D-Q6-E which are transparent


Components from left to right:
      ? Manually operated on-off valve with
      silencer (type MS6-EM1)
      ? Filter (type MS6-LF)
      ? Pressure regulator (type MS6-LRP)
      ? Flowmeter (type SFAB)
      ? Manifold

pdf file
step file

Tunnel photos

The mapping between the Air manifold valves and the Detector modules is given in the Section "Operational aspects" below.

Functional specification

  • This document discusses the requirements (e.g. the needed flow of air)
  • Initially considered layout:
  • The air inputs of the detector modules and manifold are shown in the models below
    • The detector drawing below is outdated -- in practice there is no serial connection between modules, meaning that each module has 2 independent supply lines
  • The direction of flow is important. For details, see the document above.


Operational aspects

  • As discussed in the document above, the needed air flow is:
    • 20 l/hour = 0.33 l/min per SiPM array (i.e. half module)
    • 400 l/hour = 7 l/min for the cooling manifold
    • 720 l/hour = 12 l/min in total (16*20 + 400 l/hour)
  • 20+1 individual valves allow to adjust the flow through each output of the air manifold
  • The total flow going out of the manifold can be adjusted by rotating the cylinder located at the bottom of the pressure regulator (the third element on the plate)

  • Flow settings 14-10-2015 (Bernd)
    • Total flow: 30 l/min
    • Flow into cooling manifold: ~10 l/min (two tubes)
    • Flow for all 16 SiPM arrays: ~20 l/min (test done opening only one valve at the same time: about 1 l/min)

Flowmeter interlock and wiring

Interlock for the cooling chiller

  • The user manual of the air flowmeter provides detailed and clear instructions how to configure the flowmeter switch/TOR outputs
  • Current settings (Sept 2015):
    • Using digital output A
    • Switch setting: NO (normally open)
    • Switching Threshold: 10 l/min, Hysteresis: 5 l/min. In practical terms:
      • Increasing the flow from 0 l/min, the interlock will switch-on when the flow goes above 10 l/min
      • Then, if the flow goes down, the interlock will switch-off when the flow goes below 5 l/min (i.e. below Threshold - Hysteresis)

Cabling and wiring schemes

  • Cabling chain for the air flowmeter and the chiller PT100 probe
    • Info about the cables used and the nodes along the chain
  • Wiring for the flowmeter
    • Info about the wires used to provide 24 V to the flowmeter and the acquisition of the interlock signal
  • Connector wiring
    • Info about the junction box used to transit from a 5-pole connector to an RJ45 connector

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf BGV_Compressed_Air_v1r3.pdf r1 manage 843.9 K 2015-09-09 - 11:24 PlamenHopchev  
JPEGjpg BGV_GAZ_DETECTOR.JPG r1 manage 343.0 K 2015-03-13 - 09:28 PlamenHopchev  
JPEGjpg BGV_GAZ_MANIFOLD.JPG r1 manage 288.5 K 2015-03-13 - 09:33 PlamenHopchev  
Unknown file formatxlsx BGV_air_tube_distributor.xlsx r1 manage 10.2 K 2015-11-13 - 11:34 PlamenHopchev  
PDFpdf CS.1466985.01.A.PDF r1 manage 184.6 K 2015-06-22 - 12:06 PlamenHopchev  
Unknown file formatstep CS.1466985.01.A.STEP r1 manage 8992.8 K 2015-06-22 - 12:06 PlamenHopchev  
PNGpng CS.1466985.01.A.png r1 manage 569.3 K 2015-06-22 - 12:06 PlamenHopchev  
PDFpdf Cable_Flowmeter_5poleM12_RJ45.pdf r1 manage 69.7 K 2015-09-09 - 15:18 PlamenHopchev  
PDFpdf Connection_Chain_Chiller_Signals.pdf r1 manage 16.6 K 2015-09-09 - 15:18 PlamenHopchev  
PDFpdf Debitmetre_User_Manual.pdf r1 manage 307.3 K 2015-09-09 - 14:28 PlamenHopchev  
PDFpdf FESTO_Offer_2015_05_01_2070047285.pdf r1 manage 259.7 K 2015-09-09 - 13:27 PlamenHopchev  
PDFpdf Flowmeter_Signal_Routing.pdf r1 manage 10.6 K 2015-09-09 - 15:18 PlamenHopchev  
JPEGjpg IMG_9664.JPG r1 manage 3071.0 K 2015-11-13 - 11:23 PlamenHopchev  
JPEGjpg IMG_9665.JPG r1 manage 2533.4 K 2015-11-13 - 11:23 PlamenHopchev  
PNGpng scheme_v3.png r1 manage 64.7 K 2015-03-13 - 16:53 PlamenHopchev  
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