GB / T12224-2005 steel valves - General requirements GB / T12247-1989 steam traps classification GB / T12250-2005 steam traps term, sign, structure length GB / T12712-1991 recovery of condensate from steam heating system and steam trap technology management requirements GB / T12221-2005 metal valve structure length JB / T74-1994 pipe flange technical conditions JB / JB / T8530-1997 valve electric device model preparation method T7928-1999 common valve supply requirements GB / T12230-2005 General Valve Austria martensitic steel castings JB / T5300-2008 industrial valves material selection guidelines JB / T6438-1992 valve sealing surface plasma arc welding technical requirements JB / T7248-2008 valve cryogenic steel castings JB / T7744-1995 valve Plasma arc welding sealing surface alloy powder Shanghai Guanlong Valve Machinery Co., Ltd. Shanghai Guanlong valve Machinery Co., valves, valve out of Hong Kong, the Hong Kong provided by the Dongguan Science and Technology Co., Ltd. with the valve. Valve Co., Ltd., Dongguan Ming Kong (www.gdmgfm.com) strong, credible, butterfly and other industries in Dongguan, Guangdong has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead valve and you work out of Hong Kong into the brilliant, for a better future!