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Spectacle Blind Flanges – Uses, Dimensions, Types

Spectacle Blind Flanges

Spectacle blind flanges, also known as figure 8 blinds, are essential in many industrial piping systems. These flanges are used to block or isolate a part of the piping system during maintenance operations and provide a strong seal when closed. Understanding the different types, uses and welding techniques of spectacle blind flanges is critical for anyone working with industrial pipes.

What is Spectacle Blind Flanges?

A spectacle blind flange is a crucial component in industrial pipelines, comprising two metal discs connected by a central hinge. One disc is solid, while the other features a central hole. This design enables the blind to be rotated, effectively either blocking flow entirely or allowing it to pass through. This versatility makes spectacle blind flanges indispensable for isolating pipeline sections during maintenance or repair operations.

Spectacle Blind Flanges Uses

Spectacle blind flanges are mainly used in industries like petrochemicals, oil & gas plants, chemical refineries and pulp & paper mills. They are used to separate sections of a pipeline while performing maintenance or repairs on one part without having to shut down the entire system. This saves time and money by allowing operators to quickly and efficiently perform routine maintenance operations on their plants without disrupting production.

Spectacle Blind Flanges Welding

Spectacle blind flanges must be welded correctly to provide an effective seal and prevent any leakage from occurring. The welding process for spectacle blind flange is quite simple; it involves welding both ends together using either TIG (Tungsten Inert Gas) or MIG (Metal Inert Gas) welding methods. The most important thing to remember when welding spectacle blind flange is that the weld should be done with high-quality materials, as any imperfections can cause leakage or other problems down the line.

Spectacle Blind Flanges Types

There are two main types of spectacle blind flanges available; solid body and split body models. Solid-body models are made from one piece of material, making them stronger than split-body models, which consist of two pieces held together with bolts or clamps. It’s essential to choose the right type for your application based on factors such as pressure rating and material compatibility.

Spectacle Blind Flanges Dimensions

Spectacle Blind Flanges Dimesnions

Size in Inch Size in MM Internal Dia. Outer Dia. Center to Center Thick. Web Width Web Thick. Hole Dia Spec. Blind Weight in Kg Paddle Blank Weight in kg Paddle Spacer Blank Weight in kg
1/2 15 16 45 60 3 38 2 15.875 0.07 0.03 0.03
3/4 20 21 54 70 3 38 2 15.875 0.1 0.05 0.04
1 25 27 64 80 3 38 2 15.875 0.14 0.07 0.06
1 1/4 32 42 73 90 6.4 38 4 15.875 0.35 0.21 0.14
1 1/2 40 48 83 100 6.4 38 4 15.875 0.46 0.27 0.18
2 50 61 102 120 6.4 51 4 19.05 0.68 0.41 0.26
2 1/2 65 73 107 140 6.4 51 4 19.05 0.7 0.46 0.24
3 80 89 133 150 6.4 64 4 19.05 1.1 0.71 0.39
3 1/2 90 102 159 175 9.7 64 5 19.05 2.44 1.54 0.9
4 100 114 172 190 9.7 64 5 19.05 2.81 1.8 1.01
5 130 141 194 215 9.7 76 5 22.225 3.37 2.29 1.08
6 150 168 219 240 12.7 76 7 22.225 5.39 3.82 1.57
8 200 219 276 300 12.7 76 10 22.225 8.32 6.07 2.25
10 250 273 337 360 15.7 102 12 25.4 15.04 11.19 3.84
12 300 324 406 430 19.1 102 15 25.4 26.95 19.77 7.18
14 350 356 448 475 19.1 108 15 28.575 32.94 24.07 8.87
16 400 406 511 540 22.4 108 17 28.575 50.27 36.73 13.54
18 450 457 546 580 25.4 114 20 31.75 61.79 47.55 14.23
20 500 508 603 635 28.4 121 22 31.75 83.67 64.85 18.82
24 600 610 714 750 31.8 140 24 34.925 129.3 101.8 27.49

Conclusion

Spectacle blind flanges are essential in many industrial piping systems due to their ability to quickly isolate pipeline parts during maintenance operations without shutting down the entire system. When choosing a type of spectacle blind flange, it’s essential to consider factors such as pressure rating and material compatibility to ensure that you get the best results possible from your setup. Additionally, proper welding techniques must be observed when installing spectacle blinds to ensure that they form an airtight seal that prevents leaks from occurring during operation. By understanding how these components work, you can make sure that your industrial piping system runs smoothly and efficiently over time!

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