Understanding joints, connections and the most common flange types used in the oil and gas industry is a core requirement to keep these levels of safety and attitudes the same. To ensure your always familiar with these, here are 6 of the most common flange types and a description of what they are best used for:
Weld-neck Flange
Complete with a tapered hub, these flanges are recognisable and used in high pressure environments. The flange is particularly useful under repeat bending conditions.
Slip-on Flange
A flange which is slipped over the pipe and welded both inside and outside to increase strength and prevent leakage. A favourite for engineers compared to the weld-neck due to their lower cost.
Lap-joint Flange
Used in conjunction with a lap joint stub end, the flange is slipped over the pipe but not fastened, unlike the slip-on. Instead the flange is held in place by the pressure transmitted to the gasket by the flange pressure against the back of the pipe lap.
Threaded Flange
Used in special circumstances, the threaded flange can be attached to the pipe without being welded. These are usually positioned on pipes with a deep wall thickness, used to create the internal thread.
Blind Flange
Manufactured without a bore, these flanges are used to blank off the end of piping, valves and pressure vessel openings. They are also most suitable for high pressure temperature applications.
Socket-weld Flange
With a static strength equal to the Slip-on flange, the Socket-weld is connected with the pipe with 1 fillet weld on the outside of the flange. Due to corrosion issues, some processes do not allow this flange.
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)
