Flanges are used to connect two pipes or to connect a pipe to a fitting or equipment. Flanges are typically made of steel, stainless steel, or cast iron, and they are held together by bolts and a gasket. The gasket provides a seal between the flanges to prevent leaks.
Flanges – Reliable Connectors in Piping Systems
Flanges are essential mechanical components designed to connect pipes, valves, pumps, and other equipment within a piping system. They provide a robust joint that can be easily assembled or disassembled, making them a preferred choice in industries where regular maintenance, inspection, or system modification is required.
These connectors are typically circular discs with bolt holes and a central opening that matches the pipe’s diameter. When paired with gaskets and fasteners, flanges create a secure and leak-resistant seal, ensuring the safe transport of fluids and gases under a wide range of pressures and temperatures.
One of the major advantages of flanges is their versatility. They are available in various materials, such as carbon steel, stainless steel, alloy steel, and even non-metallic options, to suit different environmental and operational needs. Industries like oil and gas, chemical processing, power generation, marine, and water treatment rely heavily on flange technology to maintain system efficiency and safety.
Types of flange
Slip-On Flange : – The Slip-on type flange is attached by welding inside as well as outside. These flanges are of forged construction
Socket Weld Flange: – The Socket Weld flange is welded on one side only. These are used for small bore lines only.
Screwed Flange : – The Screwed flange is used on pipe lines where welding cannot be carried out.
Lap Joint. Flange: – The Lap Joint flange is used with stub ends. The stub ends are welded with pipes & flanges are kept loose over the same.
Weld Neck Flange : – The Welding neck flanges are attached by butt welding to the pipe. These are used mainly for critical services where the weld joints need radiographic inspection.
Blind Flange: – The Blind flanges are used to close the ends which need to be reopened for modification, servicing or extending the header length for increasing the capacity.
Reducing Flange : – The reducing flanges are used to connect between larger and smaller sizes without using a reducer. In case of reducing flange, the thickness of flange should be that of the higher diameter.
Integral Flange : – Integral flanges are those, which are cast along with the piping Component or equipment.
Pressure temperature rating of Flange
- #150
- #300
- #400
- #600
- #900
- #1500
- #2500
Pressure temperature rating carts in the standard ASME16.5 specify the non-shock working gauge pressure to which the flange can be subjected to at a particular temperature.
Types of facing of flanges
- Flat face. (FF)
- Raised face. (R/F)
- Tongue and groove. (T/G)
- Male and female. (M/F)
- Ring type joint. (RTJ)
FAQ
1. What is the main purpose of a flange in a piping system?
A flange is used to connect pipes, valves, pumps, and other equipment, allowing for easy assembly, disassembly, and maintenance while providing a leak-tight seal.
2. What materials are flanges commonly made from?
Flanges can be manufactured from carbon steel, stainless steel, alloy steel, cast iron, aluminum, brass, and even plastic, depending on the application and environment.
3. How do flanges prevent leaks?
When bolted together with a gasket in between, flanges create a tight seal that prevents fluid or gas leakage under pressure.
4. What are the main types of flanges?
The most common types include weld neck, slip-on, blind, socket weld, lap joint, and threaded flanges, each designed for specific operating conditions.
5. What standards are used for flanges?
Flanges are manufactured according to standards such as ASME, ANSI, DIN, JIS, and BS to ensure compatibility, safety, and quality.
6. How do you select the right flange for an application?
Selection depends on factors such as pressure rating, temperature, pipe size, fluid type, and material compatibility.
7. What is the role of a gasket in a flanged joint?
A gasket fills the microscopic gaps between two flange faces, ensuring a tight and reliable seal.
8. Can flanges be reused?
Yes, flanges can be reused if they are free from damage, corrosion, or deformation, though gaskets should always be replaced.
9. What is a flange pressure class?
The pressure class (e.g., 150, 300, 600) indicates the maximum pressure the flange can handle at a given temperature.
10. Why are blind flanges used?
Blind flanges are used to close the end of a pipeline or isolate a section for maintenance or future expansion.
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