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Flange common sense

First, what is loose flanges , loose flanges used in any place and in what tube ?
Loose flanges that can be active flange, generally supporting the drainage accessories ( expansion joint is the most common ) , the manufacturers factory expansion joints have a flange on both ends directly with the project pipeline , device with bolts .
Second, how and pipe flanges are connected together
What parts welded ?
Flange Classification lot . Usually with a flat flange , welded flange ( long-necked flanges ) , Loose flanges , etc.
. Flat welding flange for low pressure , the use of plug welding , both sides of welding, welding depth from flange sealing surface 2-5mm,
Can be directly butt welded flange , loose flange bolts without welding .
Third, the flange mean ?
The flange is a link member for connecting the valve and the pipe , and pipe is connected to the valve when the connections are connected by bolts , so the valve two end faces with N is a uniform flange bolt holes .
1 , flange : flange is flange transliteration , meaning flanged things, parts, this part may be a separate , that is, the flange can also be a combination of type, such as pipes with one or both ends flange , the flange on top of a number of through holes for mounting screws , some bearing outer ring having a flange , the flange can have holes , holes can not only be used for the positioning wall .
2 , flange type : valve with connecting piping or equipment is used in flange connection, this connection is known as a flange .
Fourth, what is the flange ?
Flange is a disk-shaped parts, the most common projects in the pipeline , flanges are used in pairs . In the pipeline project , mainly used for pipe flange connections. The need to connect pipes, various mounting a flange, you can use low-pressure pipe thread flange, 4 kg more pressure on the use of welding flanges. With two sealing points between the flange and fastening with bolts . Different pressures have different flange thickness and a different bolt . Pumps and valves, and piping connections , these local facilities and equipment , but also made ​​the corresponding flange shape , also known as the flange connection. Any use of the two planes in the surrounding bolted connections simultaneously closed parts, generally known as the " flange " , such as ventilation pipe connections , this type of parts can be called a " flange parts ." But this is only one device connected to a local , such as flanges and pump connections, bad water pump called the " flange parts ." Relatively small, such as valves , etc., can be called " flange parts ."
Fifth, the flange is how a connection ?
Flanged pipeline construction is an important connection.
That the two flanged pipes, fittings or equipment , each fixed in a first flange , between two flanges , with flange gasket , fastened together with bolts , to complete the connection. Some fittings and equipment already comes with flange, also belongs to the flange connection.
Flange screw connection ( wire tapping ) flange and welded flanges. Small- diameter wire pressure flange, high pressure and low pressure large diameter welded flanges are used , different pressures and the thickness of the flange diameter and the number of connecting bolts are different .
According to different pressure levels, there are different materials, flange gaskets , asbestos mat from the low pressure , high pressure to the metal pads are asbestos mat .
Flanged easy to use, able to withstand greater pressure.
In industrial pipe , flange connection to use very extensive. The family , the pipe diameter is small, and a low-voltage , see the flange connection. If a boiler room or a production site, everywhere flanged pipes and equipment.
That the two flanged pipes, fittings or equipment , each fixed in a first flange , between two flanges , with flange gasket , fastened together with bolts , to complete the connection. Some fittings and equipment already comes with flange, also belongs to the flange connection.
Note that when connecting bolts , especially when all you want to do the same bolts tight .
Sixth, what is the usefulness of the flange ?
Flange is used to locate the .
For example there is a fuel tank mounting flange is called , is such a symmetrical rectangular four weeks to play four holes in the middle there is a big hole and the cylinder diameter identical to the rectangular cover on the cylinder between them can be soldered after the other are fixed together , cylinders and other things that rely on this connection is around four rectangular hole connections , this can be called a rectangular flange .
Seven , orifice flange connection flange and ordinary differ ?
That the two pipes, fittings or equipment , each fixed in a first flange , between two flanges , with flange gasket , fastened together with bolts , to complete the connection.
Admiral is the orifice flowmeter orifice flange plate connection ( orifice flowmeter measurement section ) to the pipe , flange on both sides in the middle of the plate fixed by flanges to take pressure point , lead to differential the transmitter to measure flow .
Eight , to ensure the mounting flange does not leak oil, on the installation, pay attention to what issues ?
1, the flange should have sufficient strength , fastening shall not deformed. Flange sealing surface should be smooth and clean , the installation should carefully cleaning the grease and rust .
2 , the gasket should have good oil and anti-aging properties , as well as good flexibility and mechanical strength. Installation should be chosen according to the shape of the junction of different sections and sizes gasket and placed correctly .
3 , flange clamping force should be uniform , the amount of compression pads should be controlled in 1/ 3 left there .
Nine , butt welding flange flange peace What is the difference ?
Welded flange is the interface with the end of the pipe diameter and wall thickness of the pipe to be welded , as the same on the two tubes welded together .
Flat welding flanges are machined at the interface slightly larger than the outer diameter of the tube with a cavity in Taiwan , inserted inside the pipe welding .
Butt welding performance is good , corrosion is relatively small.
And butt weld flanges and pipe connections are when welding , flat welding flange welding only one side welding without weld pipe and flange connections inside the mouth , butt welding flange mounting flange pair needs surface welding. So flat welding flange generally used for low and medium pressure pipe , welded flange for medium and high-pressure pipe connections , welded flange is generally at least PN2.5MPa, using the butt is to reduce the stress concentration , the general mostly with welded flange neck flange also called nipple flange .
So welded flange mounting costs, labor costs , and auxiliary fees are high , because the more a process .
Welded flange not all need to double welded inside and outside , there are no special requirements are generally just outside welding a never seen 1/ 2 of it :) welded flange , flat weld is better weld friends because a good pair of vertical pipes and flanges , pipes will not ramp .
Ten , flanges and valves difference ?
Faucet valves are the same thing , or that the tap is a valve . Can be unscrewed , water, or gas can flow out ; can be closed , the water will not flow .
Home tap is screwed on the pipe , but with some of the factory pipes inside the water or gas , the pressure is very high, with a threaded connection too strong, welded on directly or use other methods to connect . Is one of the flange connection method .
Eleven , flange marking and marking example
A national standard markup : flange DN should , nominal pressure , the sealing surface in the form code , equipped with steel pipe series code ( equipped with metric tube codenamed " Series 2 " , equipped with inch pipe is not marked ) and standard number labeled .
Tag example : nominal diameter 80mm, nominal pressure 4.0MPa (25bar) convex welded steel pipe flange ( equipped with metric pipe )
Flange DN80-PN40 M ( Series 2) GB/T9115.2-2000, DN 100mm, nominal pressure 5.0MPa (25bar) projecting face with a neck flat welding steel pipe flanges ( equipped with BSP ) Flanges DN100-PN50 RF GB/T9116.1-2000.
2, the machinery of the standard tags :
Tag example : DN 500mm, nominal pressure 1.6MPa, Series 2 projecting surface flat welding steel pipe flanges
Flange 500-16 JB/T81-94
DN 300mm, nominal pressure 6.4MPa, Series 1 concave welded steel pipe flange
Flange 300-64B ( Series 1) JB/T82.2-94
( Note: The machinery of the standard default pipe diameter for the series 2 , welded flange Category : A type convex , B- concave , C-type tenon surface , D- groove surface )
3, the Ministry of Chemical Industry Standard Tag : Flange following shall mark ( recommend the use of such labeling method )
a, Standard Number : all types of pipe flanges are standard number of this standard uniform mark : HG20592.
b, flange type code specified in Table 5.0.1 .
Threaded flange according to GB/T7306 stipulated taper pipe threads, marked as "Th (Rc)" or "Th (Rp)";
Threaded flange according to GB/T12716 prescribed taper pipe threads, marked as "Th (NPT)";
Threaded flange without marking thread code , compared to Rp (GB/T7306.1).
c, flange DN DN (mm) diameter steel pipe with the applicable Series:
Integral flange , flange cover, liner flange , threaded flange for pipe diameter range of tags can be omitted ;
For International General Series Pipe ( commonly known as BSP ) flanges, mark "DN (A)";
Follow the series for the domestic steel ( commonly known as the metric pipe ) flanges, marked as "DN (B)".
d, flange nominal pressure PN, MPa.
e, the sealing surface in the form in Table 6.0.1 of the Code provisions , such as car manufacturing face flange dense grain waterline is marked as "RF (A)".
f, by user-supplied pipe wall thickness .
Weld neck flanges , welding neck collar loose flange pipe wall thickness should be marked .
g, material grades .
h, other . Adopt inconsistent with the provisions of this standard requirements or additional requirements, such as the sealing surface of the surface roughness .
Tag example :
DN 1200mm, nominal pressure 0.6MPa, equipped with metric tube protruding panel flat welded steel pipe flanges, material Q235A
HG20592 flange PL1200 (B) -0.6 RF Q235A
DN 300mm, nominal pressure 2.5MPa, equipped with a convex inch pipe with neck flat welding steel pipe flanges , the material is 20 steel
HG20592 flange SO300 (A) -2.5 M 20
DN 150mm, nominal pressure 16.0MPa, equipped with ring joint face inch pipe welded steel pipe flanges with neck , the material is 16Mn, pipe wall thickness of 10mm
HG20592 flange WN150 (A) -16.0 RJ S = 10mm 16Mn
Nominal diameter of 200mm, nominal pressure 1.0MPa, equipped with metric pipe weld raised face ring loose steel pipe flanges , material : flange 20 welded ring 316 , pipe wall thickness of 4mm
HG20592 flange PJ/SE200 (B) -1.0 RF S = 4mm 20/316

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