What types of flanges are there?

How many types of flanges are there? How are they classified? What are the manifestations of flanges? Types of flanges
1. According to the classification of national standard flanges: integral flanges, threaded flanges, butt welding flanges, flat welding flanges with necks, socket welding flanges with necks, butt welding ring loose flanges with necks, plate flat flanges Welding flanges, butt-welding ring plate loose flanges, flat welding ring plate loose flanges, flanged ring plate loose flanges, flange covers.
2. According to the classification of standard flanges in the chemical industry: integral flange (IF), threaded flange (Th), plate flat welding flange (PL), butt welding flange with neck
(WN ​​), flat welding flange with neck (SO), socket welding flange (SW), butt welding ring loose flange (PJ/SE), flat welding ring loose flange (P/RJ), lining Flange cover (BL (S)), flange cover (BL).
3. According to the classification of standard flanges in the petrochemical industry: threaded flanges (PT), butt welding flanges (WN), flat welding flanges (SO), socket welding flanges (SW), loose flanges (LJ) , Flange cover.
4. According to the classification of the standard flanges of the machinery industry: integral flanges, butt welding flanges, plate flat welding flanges, butt welding ring plate loose flanges, flat welding ring plate loose flanges, flanged ring plate loose flanges Flange, flange cover.