(19)
(11) EP 0 719 978 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
02.05.1997 Bulletin 1997/18

(43) Date of publication A2:
03.07.1996 Bulletin 1996/27

(21) Application number: 95402914.6

(22) Date of filing: 22.12.1995
(51) International Patent Classification (IPC)6F17C 9/00
(84) Designated Contracting States:
DE FR GB IT NL

(30) Priority: 30.12.1994 US 366468
25.07.1995 US 506867

(71) Applicant: L'AIR LIQUIDE, SOCIETE ANONYME POUR L'ETUDE ET L'EXPLOITATION DES PROCEDES GEORGES CLAUDE
F-75321 Paris Cédex 07 (FR)

(72) Inventors:
  • Kimura, Masao
    Tsuchiura-shi, Ibaraki 300 (JP)
  • Tsukamoto, Toshiyuki
    Ushiki-shi, Ibaraki-Pref.300-12 (JP)
  • Tarutani, Kohei
    Tsukuba-shi, Ibaraki 305 (JP)
  • Friedt, Jean-Marie
    Chuo-ku, Tokyo 104 (JP)

(74) Representative: Vesin, Jacques et al
L'AIR LIQUIDE, S.A., Service Propriété Industrielle, 75 quai d'Orsay
F-75321 Paris Cédex 07
F-75321 Paris Cédex 07 (FR)

   


(54) A process for distributing ultra high purity gases with minimized corrosion


(57) A process for reducing corrosion in a gas distribution network of ultra high purity gas or any part of said distribution network, comprising:

(a) Wet cleaning the gas distribution network or at least one part thereof with a wet cleaning agent,

(b) Liquid drying said gas distribution network or said at least one part thereof with an H2O desorbing liquid drying agent selected from the group consisting of acetone dimethylacetal DMP, 2.2 dichloropropane DCP or 2.2 dibromopropane DBP, mixtures thereof and any equivalent thereof,

(c) purging said gas distribution network or any said part thereof with a dry high purity gas comprising less than 1 ppm of any impurity, and

(d) evacuating said gas distribution network or any said part thereof at a pressure which is lower than 5x104 Pascal

(e) exposing said gas distribution network or said any part thereof to an atmosphere comprising an ultra high purity corrosive gas or air.







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