Regarding 8-character blind plates
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In the current HG/T 21547-2016 standard, the 8-character blind flanges do not come with an RF (raised surface) design. I would like to ask whether RF flanges can be used in conjunction with the FF (flat surface) 8-character blind flanges specified in this standard, for a pressure level of PN16 and a diameter of DN80
According to the standard HG/T 21547-2016 \"Steel Pipe Flanges (European Series)\", if an 8-shaped blind flange is available only in the flat (FF) type and not in the raised face (RF) type, it is generally not recommended to use such a flat 8-shaped blind flange in conjunction with an RF flange. A raised face (RF) flange has a protruding sealing surface, while a flat face (FF) flange has a flat sealing surface. They have different sealing principles and are designed for various sealing and installation conditions. If the planar 8-digit dial is directly connected to an RF flange, it may not ensure a good sealing effect, especially when used at higher pressure levels. Regarding the situation you mentioned, with a pressure rating of PN16 and a diameter of DN80, if standard 8-character flange plugs in the RF style are not available, it is recommended that you contact specialized manufacturers of flange plugs to see whether there are products that meet your requirements, or whether it is possible to have RF-style 8-character flange plugs customized. When in use, it is necessary to ensure that the flange matches the type of blind plate, pressure rating, and dimensions, etc., to guarantee the safety and sealing of the system. If the sealing requirements in your application are not particularly high, it is possible to compensate for any mismatches in the sealing surfaces by using appropriate gaskets and sealing materials; however, this usually requires a professional assessment to determine whether it is feasible based on the actual conditions of use. It is recommended that you consult a professional piping engineer or flange blind plate manufacturer before making a final decision, to ensure safe and reliable fitting. .
The 8-character blind flange of the BLF80-PN16-FF-S31603/HG/T21547-2016 series is selected.
It is not recommended to use different types of flanges together
Obviously, there is no problem; the 8-character blind flanges we design have FF faces, while the flanges have RF faces.
There are no issues with actual operation, provided that the gasket is installed properly
Both theory and practice are acceptable; note that concave flanges do not match flat eight-shaped blind plates, and this issue persists even when internal gasket rings are used.