Spectacle Blind Flange–also known as a figure-8 blind–is generally a piece of metal that is cut to fit between two pipe flanges and usually sandwiched between two gaskets.
A spectacle blind is often made from two metal discs that are attached to each other by a small section of steel. The shape is similar to a pair of glasses or “spectacles” – hence the name spectacle blind. One end of the blind will have an opening to allow flow through the pipe during operation and the other end is solid to block flow during maintenance.
|Size||Weld neck flange:1/4″-160″
Class 150 ,Class 300, Class 600, Class 900A ,Class 1500,Class 2500.
|Flange Facing Types||
Flat face(FF),Raised face(RF),Tongue(T),Groove(G),Female(F),Male(M),Ring type joints face(RJ/RTJ)
Type A(Flat Face),Type B(Raised Face),Type C(Tongue),Type D(Groove),Type E(Spigot),Type F(Recess),Type G(O-Ring Spigot),Type H(O-Ring Groove)
ASTM A105,ASTM A105N,GB 20,C22.8.
Alloy steel: ASTM/ASME A234 WP 1-WP 12-WP 11-WP 22-WP 5-WP
ASTM/ASME A403 WP 304-304L-304H-304LN-304N
ASTM/ASME A403 WP 316-316L-316H-316LN-316N-316Ti
ASTM/ASME A403 WP 321-321H ASTM/ASME A403 WP 347-347H
ASTM/ASME A402 WPL 3-WPL 6
ASTM/ASME A860 WPHY 42-46-52-60-65-70
|Standards||ASME ANSI B16.5,ASME ANSI B16.47.
API 605,API 6L.
MSS SP 44
BS1560,BS 4504,BS 10.
AFNOR NF E29-200-1
UNI 2276. UNI 2277.UNI 2278 .UNI 6089 .UNI 6090
|Industrial Processes||Die forging,Machining.|
|Application for weld neck flanges||Natural gas,chemical,petroleum,ship building,marine,paper making, metallurgy, electric, power, boiler , etc.|