What are different types of flanges?

Flanges are used in piping systems to connect pipes with various other equipment such as valves that allows easy assembly / disassembly and maintenance of the system. Various types of flanges are available as per ASME B16.5 and B16.47 standard. In this article we will discuss various types of flanges with pictures. We suggest you also read this article on various types of check valves their working and applications.

Types of Flanges

Various types of flanges in various materials (Stainless steel, monel etc. ) are used for various applications. Here is the list of various types of flanges:

  1. Welding Neck Flange
  2. Blind Flange
  3. Threaded Flange
  4. Socket Weld Flange
  5. Lap Joint Flange
  6. Slip-on Flange
Welding Neck Flange
this image shows a welding neck flanges

The welding neck flanges consist of a long tapered hub that goes inside the pipe to be fitted and at the end butt welding is required to join flange with the pipe or pipe fittings. They are used in High temperature and pressure applications.

Blind Flange
this image show a blind type of flange

Blind flanges do not consist of any bore. They are used to terminate the flow of the liquid. As shown in the above image, blind flange is used at the end and connected with another flange using nuts and bolts and gaskets.

Threaded Flange
this image shows a threaded flange used in piping system.

Threaded flanges consist of threads inside the bore of the flange. The pipe or other fitting with threads similar to flange are connected with flange using screw joint. Therefore welding is not required to join the flange with pipe. But in some cases welding is done at some points to increase connection strength.

Socket Weld Flange
this image shows a Socket Weld Flange

In Socket weld flanges, firstly the pipe is inserted inside the socket of the flange while maintaining the required gap between socket end and the pipe. Afterwards pipe and flange are  fillet welded to create the joint. They are used with smaller pipe diameters and low temperature & pressure conditions.

Lap Joint Flange
this image shows a Lap Joint Flange

Lap joint Flange consists of parts : stub end and lap joint ring flange. Stub end is placed over the lap joint flange. To create the joint, the stub end is butt welded to the pipe and the flange ring is aligned with the mating ring.

Slip-on Flange
This image shows a Slip-on Flange

In Slip-on flanges, firstly pipe to be connected is slid inside the flange. Afterwards two fillet welds (inside and outside the flange cavity) are used to connect pipe and pipe fittings to the flange.

Selection of Flanges

Following points shall be considered during the selection of various types of flanges.

  1. Required type of flange
  2. Pressure Rating
  3. Applicable Standard (ASME or DIN)
  4. Flange Facing
  5. Flange Material
  6. Size of the Flange
  7. Flange Tolerance
  8. Wall thickness of the flange.

We will keep adding more information on the Various types of Flanges with pictures used in piping system. Please add your comments or questions on the various types of Flanges in the comment box. We suggest you also read this article on various types of valves used in piping system and their applications.

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