Who has seen a flange with six bolt holes?
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The equipment outlet has a DN150 size, and the flange surface features six bolt holes; the sealing type is full flat (FF). Which standard is it compliant with? This post was last edited by Stepbystep on 2009-4-20 15:05]
Atmospheric pressure outlet, or vent outlet?
Vacuum (air pressure) and vent ports.
General standards specify that the number of circular holes on the flange surface should be a multiple of 4; I have never seen 6 circular holes.
I think the number of bolts is calculated based on the clamping force required for the pipe.
This is a non-standard flange, custom-made.
Mm-hm. Agree with what was said above. Generally, it is a multiple of 4. This way, the force distribution is more even: D
Yes, the holes for flange bolts are always multiples of 4; I’ve never seen any with 6 bolt holes. It must be a mistake, or it’s a non-standard design.
Standard flanges should be used as much as possible; if non-standard flanges are required due to process needs, they can be designed and manufactured. However, the fittings that match this flange should also use non-standard holes. Design standards for commonly used pressure pipeline equipment 1) GB50316-2000 \"Code for Design of Industrial Metal Piping\" ； 2) GB50251-94 \"Code for Design of Gas Pipeline Engineering\" ； 3) GB50253-94 \"Code for Design of Oil Pipeline Engineering\" ； 4) GB50028-93 \"Code for Design of Urban Gas\" (1998 edition) (with partial revisions in 2002) ； 5) GB50030-91 \"Code for Design of Oxygen Stations\" ； 6) SH3059-2001 \"General Rules for the Selection of Materials for Petrochemical Pipeline Design\" ； 7) SH3064-1994 \"Selection, Inspection, and Acceptance of General Steel Valves for Petrochemical Industry\" ； 8) HG/T20646 \"Specifications for the Design of Pipeline Materials in Chemical Plant Equipment\".
For non-standard cases, engineering piping is a real hassle! There’s no place to buy it either.
Some have flanges with 6 holes; some threaded flanges also have 6 holes. I’ve never seen ones with such a large diameter
Many of the device connections are not standard; a 6-hole FF flange with DN150 is likely used only under atmospheric pressure or very low pressures. We commonly use flanges that comply with the hg20593 standard
The flanges of non-metallic containers are all of the FF type; those with six holes are also available
A few days ago, a customer from outside the province came here and brought a flange similar to the one you described. The DN150 version has 6 holes, and it’s painted black. I checked the GB, HG, and ASME API 6A standards – all of them require at least 8 holes; I couldn’t find any standard version with 6 holes. Additionally, the outer diameter of this flange doesn’t conform to any standard either. It seems it was custom-made to have 6 holes; if that’s the case, the only option is to order it customly
It must have been done by oneself; it’s not standard