1. According to the chemical industry (HG) industry standard: integral flange (IF), threaded flange (Th), plate flat welding flange (PL), necked butt welding flange (WN), necked flat welding flange (SO), socket welding flange (SW), butt welding ring loose sleeve flange (PJ / SE), flat welding ring loose sleeve flange (PJ / RJ), lining flange cover (BL (S)), Flange cover (BL) [2].
2. According to the petrochemical (SH) industry standard: threaded flange (PT), butt welding flange (WN), flat welding flange (SO), socket welding flange (SW), loose sleeve flange (LJ) Flange cover (not shown).
3. According to the mechanical (JB) industry standard: integral flange, butt welding flange, plate flat welding flange, butt welding ring plate loose sleeve flange, flat welding ring plate loose sleeve flange, flange ring plate loose sleeve Flange, flange cover.
4. According to national (GB) standards: integral flanges, threaded flanges, butt welding flanges, flat welding flanges with necks, socket welding flanges with necks, butt flanges with neck loose sleeves, plate flat Welding flange, butt welding ring plate loose sleeve flange, flat welding ring plate loose sleeve flange, flange ring plate loose sleeve flange, flange cover