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Types of Flange face

Types of Flange face

AUTHOR : _ _ Date : 3/11/2013 10:37:55 PM

• FLANGE FACES


With
flange Face the form and implementation of the side of a flens are meant, where a sealing ring or gasket will be placed. The most used types are:

1. Raised Face (RF)
2. Flat Face (FF)
3. Ring-Type Joint (RTJ)
4. Male-and-Female (M&F)
5. Tongue-and-Groove (T&G)


RAISED FACE (RF)

The Raised Face type are the most applied flange type, and is easily to identify. It is referred to as a raised face because the gasket surfaces are raised above the bolting circle face.






Diameter and height are in ASME B16.5 defined, by Pressure Class and diameter. The height in Pressure Class up to 300 Lbs is approximately 1.6 mm, and in Pressure Class 400 up to 2500 Lbs the height is approximately 6.4 mm. 

Pressure rating of the flange determines the height of the raised face.

The purpose of a RF flange is to concentrate more pressure on a smaller gasket area and thereby increase the pressure containment capability of the joint.

Raised Face height

For the height measures H and B of all described dimensions of flanges on this website, with exception of the Lap Joint flange, it is important to understand and remember the following:

In Pressure Classes 150 and 300 Lbs, the height of raised face is approximately 1.6 mm (1/16 inch).
In these two Pressure Classes, almost all suppliers of flanges, show in their catalog or brochure, the H and B dimensions including the raised face height. See figure 1 on the image below.




In Pressure Classes 400, 600, 900, 1500 & 2500 Lbs, the height of raised face is approximately 6.4 mm (1/4 inch). In these Pressure Classes, most suppliers show the H and B dimensions excluding the raised face height. See figure 2 on the image above.


FLAT FACE (FF)

The flat face (full face) flange has a gasket surface in the same plane as the bolting circle face. Applications using flat face flanges are frequently those in which the mating flange or flanged fitting is made from a casting.



 

Flat face flanges are never to be bolted to a raised face flange. ASME B31.1 says that when connecting flat face cast iron flanges to carbon steel flanges, the raised face on the carbon steel flange must be removed, and that a full face gasket is required. This is to keep the thin, bittle cast iron flange from being sprung into the gap caused by the raised face of the carbon steel flange.



RING-TYPE JOINT (RTJ)

RTJ flanges have grooves cut into their faces which steel ring gaskets. The flanges seal when tightened bolts compress the gasket between the flanges into the grooves, deforming (or Coining) the gasket to make intimate contact inside the grooves, creating a metal to metal seal.




An RTJ flange may have a raised face with a ring groove machined into it. This raised face does not serve as any part of the sealing means. For RTJ flanges that seal with ring gaskets, the raised faces of the connected and tightened flanges may contact each other. In this case the compressed gasket will not bear additional load beyond the bolt tension, vibration and movement cannot further crush the gasket and lessen the connecting tension.


Ring Type Joint gaskets are metallic sealing rings, suitable for high-pressure and high-temperature applications. They are always applied to special, accompanying flanges which ensure good, reliable sealing with the correct choice of profiles and material.


Ring Type Joint gaskets are designed to seal by "initial line contact" or wedging action between the mating flange and the gasket. By applying pressure on the seal interface through bolt force, the "softer" metal of the gasket flows into the microfine structure of the harder flange material, and creating a very tight and efficient seal.


 

The most applied rings are:
1. Type R-Oval according to ASME B16.20
The original style of metallic ring joint. Used on round bottomed groove flanges though can also be used on later, flat-bottomed groove flanges. Suitable for ASME B16.5 flanges from Class 150 to 2500.
2.
Type R-Octagonal according to ASME B16.20
An improved design over the original Oval design. However these can be used only in flat-bottomed groove flanges. Suitable for ASME B16.5 flanges from Class 150 to 2500.



MALE-AND-FEMALE (M&F)

With this type the flanges must be matched. One flange face has an area that extends beyond the normal flange face (Male). The other flange or mating flange has a matching depression (Female) machined into it′s face.

Custom male and female facings are commonly found on the heat exchanger shell to channel and cover flanges.



TONGUE-AND-GROOVE (T&G)

With this type the flanges also must be matched. One flange face has a raised ring (Tongue) machined onto the flange face while the mating flange has a matching depression (Groove) machined into it′s face.
These facings are commonly found on pump covers and valve bonnets.



General flange faces such as the RTJ, T&G and the F&M shall never be bolted together. The reason for this is that the contact surfaces do not match and there is no gasket that has one type on one side and another type on the other side.

 


• 
Check all kinds of pipe fittings

1. Elbow:
45 degree elbow
45D CS butt weld elbow    45D SS butt weld elbow   45D socket weld elbow   45D threaded elbow
90 degree elbow  
90D CS butt weld elbow    90D SS butt weld elbow   90D socket weld elbow
   90D threaded elbow     street elbow
180 degree elbow  
180D CS butt weld elbow      180D SS butt weld elbow

2. Tee:
CS butt weld straight tee   CS butt weld reducing tee   SS butt weld straight tee  SS butt weld reducing tee  socket weld tee   threaded tee
   Lateral tee:
CS butt weld lateral tee   SS butt weld lateral tee   socket weld lateral tee   threaded lateral tee

3. Cross:
CS butt weld straight cross   CS butt weld reducing cross   SS butt weld straight cross   SS butt weld reducing cross   socket weld cross   threaded cross

4. Reducer:
CS concentric reducer   CS eccentric reducer  SS concentric reducer   SS eccentric reducer

5. Cap:
CS butt weld cap   SS butt weld cap   socket weld cap   threaded cap

6. Stub end:
CS stub end   SS stub end

7. Coupling:
socket weld full coupling   socket weld half coupling   threaded full coupling   threaded half coupling

8. Union:
socket weld union   threaded union

9. Socket insert:
A  B

10. Plug:
hex head plug   square head plug   round head plug

11. Bushing:
hex head bushing   flush bushing 

12. Nipple: 
TBE   PBE   TOE&POE   hex nipple

13. Swaged nipple:
concentric swage nipple   eccentric swage nipple

14. Flange:
Orifice flange   lap joint flange   threaded flange   socket weld flange   weld neck flange   blind flange   slip on flange   long weld neck flange   plate flange   large diameter flange   spectacle blind   square flange   

15. Outolet:
weldolet   socketolet   threadolet  laterolet  coupolet  elolet   nipoflange   nipolet
 







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