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- F.F. Bertinelli, G. Favre, L.M.A. Ferreira, S.J. Mathot, L. Rossi, F. Savary
CERN, Geneva
- E. Boter
CELLS, Bellaterra (Cerdanyola del Vallès)
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The dipole and quadrupole cold masses of the LHC machine require about 1700 heat exchanger tubes (HET). In operation the HET carries a two-phase flow of superfluid helium at sub-atmospheric pressure. The HET consists of an oxygen-free, seamless copper tube equipped with stainless steel ends. After an evaluation of different design alternatives, a design based on the technologies of vacuum brazing and electron beam welding has been adopted. Presence of these multiple technologies at CERN and synergies with the cleaning, handling and transport of other 15-metre components for LHC, motivated CERN to undertake this series fabrication on site. The raw copper tubes are procured in Industry, presenting challenging issues of geometric precision. Organisation of the HET fabrication includes cryomeasurements to validate cleaning procedures, characterization of welding procedures, buckling design by FEA and experimental verification, quality control during series production. The series fabrication of these long, multi-technological components is continuing successfully, respecting the project?s tight budgetary and planning constraints.
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