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pipe flange,flange supplier,valve supplier,

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pipe flange,flange supplier,valve supplier,
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Flange Connection Surface: FF vs RS

Date:2024-06-21View:416Tags:pipe flange,flange supplier,valve supplier,

Flange Connection Surface: FF vs RS


flange


Flange is a part that connects pipes to pipes and valves, and is connected to the pipe end. There are holes on the flange, and bolts make the two flanges tightly connected. Gaskets are used to seal between flanges. Flanges are divided into threaded connection (threaded) flanges, welding flanges and ferrule flanges. Flange sealing surfaces include flat face (FF), raised face (RF), male and female (MF), Tongue (T), groove face (G), and ring joint(RJ).


The sealing surface of the full plane (FF) flange is a smooth plane with a simple structure and convenient processing, which is convenient for the construction of anti-corrosion lining. The FF surface is generally used for flanges with low pressure, or the sealing surface needs to be attached with a stainless steel liner ring sealing surface to play a role in corrosion resistance. It is often used in combination with flat welding to be suitable for relatively mild operating conditions (PNg1.0); it is often used for cast iron flanges or steel flanges connected to cast iron. This flange is suitable for places with low pressure and low temperature. However, due to the large contact area between the sealing surface and the gasket, the required clamping force is large, the gasket is not easy to position during installation, and the gasket is easy to stretch or move to both sides after pre-tightening. Therefore, when using lined flanges or non-metallic flanges for connection, the use of FF face flanges can ensure that the sealing surface is not broken during tightening.


The sealing surface of the raised face (RF) flange has a protruding form and is usually used for pipe connections with medium and low pressures and medium and low temperatures. The characteristics of the RF flange are simple structure and convenient processing, and it is suitable for places where the pressure and temperature are not too high. Although some people believe that there is a possibility of gasket extrusion when used under high pressure, due to its easy installation, the RF flange is the most widely used sealing surface form below PN150.


RF is a convex flange and can be used for PN1.6~PN10MPA. FF is a flat surface, and the sealing is not as good as RF. The pressure is 1.6~2.0MPA (standard GB9113), and other forms such as RTJ and FM use higher pressures.


The gaskets of RF and FF can be used universally.


Summary


FF flanges and RF flanges each have their own characteristics and application scenarios. FF flanges are suitable for occasions with low requirements on sealing performance or mild pressure and temperature conditions due to their smooth sealing surface; while RF flanges are more suitable for medium and low pressure and medium and low temperature pipeline connections due to their prominent sealing surface design, and are widely used due to their easy installation.