Issues regarding the flange flanging stub of the loop
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Regarding the issue of the lap-joint or slip-on flange stub end used for the loop flange. The flanged short section is divided into Long or Short types; it is inappropriate to require suppliers to deviate from the standard markings for pressure ratings The reason is as follows: The flanged stub does not fall under the scope of ASME B16.5 (flanges), but rather under the scope of ASME B16.9 (fittings) ； ² The marking methods specified in the ASME B16.9 (fittings) standard or the MSS SP-43 standard do not provide specific details regarding pressure ratings; they only require that the fitting’s size designation (SCH) be marked ； ² A flanged stub with the same pipe designation (SCH) may meet the requirements of both 150# and 300# pressure classes ； ² The MSS SP-43 standard (where MSS is the acronym for the Valve and Fitting Manufacturers’ Standardization Association) is the procurement standard commonly used by general enterprises (the majority of items in existing warehouses are short flanged splices) ； ² MSS SP-43 only includes the short-type flanged fittings; the flanged fittings specified in ASME B16.9 or GB12459-2005 include both short-type and long-type versions ； ² Even the length of the long-type flanged stubs may sometimes not meet the required specifications; it is necessary to specify the desired length when placing an order ； Everyone is welcome to share their opinions. Learn together*, improve together!
It can save a lot of valuable stainless steel material!
We often use loop flange flanged splices to save material.
We use them frequently, especially for the interface flanges of stainless steel pipes and equipment.
Flanged ends are in minimal contact. I would like to ask the original poster: what criteria are used to choose between the long and short versions of flanged splices? Furthermore, flanged edges can only be used in low-pressure applications. If the diameter is not very large, replacing standard stainless steel flanges with carbon steel flanged edges does not result in significant cost savings; however, it introduces the risk of intergranular corrosion and pipeline contamination, as well as increasing the complexity of design, procurement, installation, and maintenance. If it’s just to save costs, I personally don’t think it makes much sense. Purely my personal opinion; feel free to criticize, no need to be polite:D
As long as it is feasible to use them, the cost of flanged + CS LJ flanges is definitely lower than that of WN flanges. Moreover, on-site construction with WN flanges is also simple.
We often use loop flange flanged splices, which helps save material and has not caused any problems
Our company has used flanged swivel flange flanged bends in situations where the medium temperature and pressure are not high but the medium is highly corrosive, and no problems have occurred; moreover, this approach allows for material savings.
We have only done flanging, but the intended use is not so clear. They’re pretty thin anyway. Not used very much
Some people say that \"flanged edges\" can only be used at low pressures – I wonder what era this view comes from? Everyone should study carefully the new **standard GB12459-2005 \"Steel Butt-Welded Seamless Fittings\"**, which contains detailed explanations. We often use it on pipes with a pressure of 1500# (260 Bar) and a diameter of DN100, and there are no issues at all. It is rather the flanging of low-pressure loop flanges that presents problems, especially in pipes subject to water hammer. The main reason is that the quality produced by small factories is too poor!
We are a coal chemical enterprise. Flanged flanges are generally used in: 1. Pipelines with relatively low pressure, <1.6 MPa； 2. Pipes that are frequently disassembled and require cleaning ； 3. Pipelines carrying corrosive media or acidic media. Based on the usage in our factory, no standard was found!