Basic introduction of flange
Pipe flanges and their gaskets and fasteners are collectively referred to as flange joints.
Application:
Flange joint is a kind of component widely used in engineering design. It is an essential part of piping design, pipe fittings and valves, and also an essential component of equipment and equipment parts (such as manhole, sight glass level gauge, etc.). In addition, flange joints are often used in other disciplines, such as industrial furnaces, thermal engineering, water supply and drainage, heating and ventilation, automatic control, etc.
Texture of material:
Forged steel, WCB carbon steel, stainless steel, 316L, 316, 304L, 304, 321, chrome-molybdenum steel, chrome-molybdenum-vanadium steel, molybdenum titanium, rubber lining, fluorine lining materials.
Classification:
Flat welding flange, neck flange, butt welding flange, ring connecting flange, socket flange, and blind plate, etc.
Executive standard:
There are GB series (national standard), JB series (mechanical department), HG series (chemical department), ASME B16.5 (American standard), BS4504 (British standard), DIN (German standard), JIS (Japanese standard).
International pipe flange standard system:
There are two main international pipe flange standards, namely the European pipe flange system represented by German DIN (including the former Soviet Union) and the American pipe flange system represented by American ANSI pipe flange.
1. Plate type flat welding flange
advantage:
It is convenient to obtain materials, simple to manufacture, low in cost and widely used.
Disadvantages:
Due to its poor rigidity, it should not be used in chemical process piping systems with requirements of supply and demand, flammability, explosiveness and high vacuum degree, and in highly hazardous situations.
The sealing surface type has flat and convex surfaces.
2. Flat welding flange with neck
The slip-on welding flange with neck belongs to the national standard flange standard system. It is one form of national standard flange (also known as GB flange) and one of the flanges commonly used on equipment or pipeline.
advantage:
The on-site installation is convenient, and the process of welding seam rubbing can be omitted
Disadvantages:
The neck height of the slip-on welding flange with neck is low, which improves the rigidity and bearing capacity of the flange. Compared with the butt welding flange, the welding workload is large, the consumption of welding rod is high, and it can not withstand high temperature and high pressure, repeated bending and temperature fluctuation.
3. Neck butt welding flange
The sealing surface forms of the neck butt welding flange include:
RF, FM, M, T, G, FF.
advantage:
The connection is not easy to deform, the sealing effect is good, and it is widely used. It is suitable for pipelines with large fluctuations in temperature or pressure, high temperature, high pressure and low temperature, and also for pipelines transporting expensive media, flammable and explosive media, and toxic gases.
Disadvantages:
The neck butt-welding flange is bulky, bulky, expensive, and difficult to install and locate. Therefore, it is easier to bump during transportation.
4. Socket welding flange
Socket welding flange is a flange welded with steel pipe at one end and bolted at the other end.
Sealing surface type:
Raised face (RF), concave and convex face (MFM), tenon and groove face (TG), ring joint face (RJ)
Scope of application:
Boiler and pressure vessel, petroleum, chemical, shipbuilding, pharmaceutical, metallurgy, machinery, stamping elbow food and other industries.
Commonly used in pipelines with PN ≤ 10.0MPa and DN ≤ 40.
5. Threaded flange
The threaded flange is a non-welded flange, which processes the inner hole of the flange into pipe thread and connects with the threaded pipe.
advantage:
Compared with flat welding flange or butt welding flange, threaded flange has the characteristics of convenient installation and maintenance, and can be used on some pipelines that are not allowed to be welded on site. Alloy steel flange has sufficient strength, but it is not easy to weld, or the welding performance is not good, threaded flange can also be selected.
Disadvantages:
When the temperature of the pipeline changes sharply or the temperature is higher than 260 ℃ and lower than - 45 ℃, it is recommended not to use threaded flange to avoid leakage.
6. Blind flange
Also known as flange cover and blind plate. It is a flange without holes in the middle for sealing the pipe plug.
The function is the same as that of welded head and threaded pipe cap, except that blind flange and threaded pipe cap can be removed at any time, while welded head cannot.
Flange cover sealing surface:
Flat (FF), raised face (RF), concave and convex face (MFM), tenon and groove face (TG), ring joint face (RJ)
Post time: Feb-28-2023
