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 manholes, liquid level gauge of visual mirror, etc.). In addition, other professional if industrial furnace, heat engineering, water supply and drainage, heating and ventilation, automatic control, also often use flange joint.
Forged steel, WCB carbon steel, stainless steel, 316L, 316, 304L, 304, 321, chromium-molybdenum steel, chromium-molybdenum-vanadium steel, molybdenum titanium, rubber lining, fluorine lining material.
10 flange types and features
1, plate type flat welding flange
Plate welding flange (chemical standard HG/T20592, national standard GB/T9119, mechanical JB/T81).
It is convenient to draw materials, simple to manufacture, low cost and widely used.
Rigid poor, therefore must not be used in supply and demand, flammable, explosive and high vacuum requirements of chemical process piping system and high, extremely harmful occasions.
2, with neck flat welding flange
Flange with neck flat welding belongs to the GB flange standard system, is one of the manifestations of GB flange (also known as GB flange), is one of the commonly used flanges on equipment or pipelines.
Field installation is more convenient, can omit welding patting kneading process.
The neck height of flat welded flange with neck is lower, which improves the rigidity and bearing capacity of flange. Compared with butt-welding flanges, welding workload is large, welding rod consumption is high, can not withstand high temperature and pressure and repeated bending and temperature fluctuations.
3, with neck butt welding flange
The connection is not easy to be deformed, the sealing effect is good, the application is widespread, is suitable for the temperature or the pressure big fluctuation pipeline or the high temperature, the high pressure and the low temperature pipeline, also USES in the transportation price expensive medium, the flammable explosive medium, the toxic gas pipeline.
Flange with neck butt welding is bulky, bulky, expensive and difficult to install and locate, so it is easier to bump in transit
4. Integral flange
The integral flange is a type of flange connection. It is also a kind of pipe flange with neck butt welding steel. Material has carbon steel, stainless steel, alloy steel and so on.
In various domestic standards, the use of IF to express the overall flange. It is mainly used in high pressure pipelines, and the production process is generally casting.
In the flange type is a "IF" to represent the type of the whole flange. Generally for the face (RF), if in the flammable, explosive, high and extremely dangerous service conditions, you can choose in addition to RF face convex concave surface (MFM) and tenon groove surface (TG) form of the sealing surface.
5. Socket welding flange
Socket welding flange is a flange with one end welded to the steel pipe and the other end bolted.
Boiler and pressure vessel, petroleum, chemical industry, shipbuilding, pharmacy, metallurgy, machinery, food and other industries.
PN 10.0MPa, DN 40 pipe.
6. Thread flange
Threaded flange is a kind of non-welding flange, which processes the inner hole of the flange into pipe thread and connects it with the pipe with thread.
Compared with flat or butt welding flanges, thread flanges are easy to install and maintain and can be used in some pipelines where welding is not allowed on site. Alloy steel flange has enough strength, but not easy to weld, or welding performance is not good, can also choose thread flange.
In the pipe temperature changes or sharply temperature higher than 260 ℃ below - 45 ℃ under the condition of threaded flanges are not recommended, so as to avoid leakage.
7. Loosen the sleeve flange of the butt welding ring
The loose sleeve flange of the welding ring is a movable flange piece, which is usually matched with the water supply and drainage fittings. When the factory leaves the factory, both ends of the telescopic joint have a piece of flange, which is directly connected with the pipe and equipment in the project with bolts.
The purpose of loose sleeve flange with butt welding ring is generally to save materials. The structure is divided into two parts, one end of the pipe is connected to the pipe, and the other end is made into butt welding ring. The flange is made of low grade material, while the pipe part is made of the same material as the pipe, so as to save materials.
Cost saving, when the pipe material is special and expensive, the cost of welding flange of the same material is high.
Not convenient for welding or processing or required strength, such as plastic pipe, glass pipe and so on.
Convenient for construction, such as connecting flange bolt hole is not easy to align or prevent future replacement equipment flange bolt hole changes.
Low pressure and low strength at the welding ring (especially when the thickness is less than 3mm)
8. Flush the ring and loosen the sleeve flange
The flanges are movable flanges, which are directly connected with the bolts used for pipes and equipment in engineering.
The purpose of using flat welding ring loose sleeve flange is generally to save data. Its structure is divided into two parts, one end of the pipe is connected with the pipe, one end is made into flanging, and the flange part is covered on the flanging.
It is convenient for welding or processing or requires high strength, such as plastic pipe, glass pipe and so on.
Convenient for construction, such as connecting flange bolt hole corresponding to convenient alignment or prevent future replacement equipment flange bolt hole changes.
When the price is high, save your money. When the pipe material is special, the cost of welding the flange of the same material is high.
Accept low pressure.
Low strength (especially when the thickness is less than 3mm) at the welding ring.
9. Flange cover
Also called blind flange, blind plate, is the middle without hole flange, for sealing pipe plug. The function is the same as that of the welded head and the threaded cap, except that the blind flange and the threaded cap can be removed at any time, while the welded head is not.
10. Lining flange cover
The lining flange cover is a blind flange that comes close to the side of the medium for surfacing stainless steel as a whole. The lining flange cover is used as the blind plate on the pipeline with corrosive medium.