A Spectacle Blind Flange – also known as a figure-8 blind flange – 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. They are generally installed as a permanent device to separate process piping systems.
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Spectacle Blind Flange Definition:
Spectacle blind flange (spectacle flange) is also called figure-8 blind flange, it is made of two pieces metal discs which are joint together by a part of steel handle. The spectacle blind flange is a safety device used to isolate a section of pipeline or equipment when they need to be inspected or removed from piping system. It is not like a valve,the spectacle blind flange is a permanent or long term isolation block.
Parts of the spectacle blind flange:
One piece disc of the spectacle flange is a blind without any hole on it, is could block the flow fluid when working, another piece disc is a blind which have an opening to allow the fluid run through the pipe when working. The spectacle blind flange shape is like a pair of glasses, so it is also called glasses flange. The spectacle flange can be rotated to place either the blind or hollow end within a piping system, thereby the system could be opening or closing.
The sealing face of spectacle flange:
The spectacle blind flange is used between two flanges, the two sides of the spectacle should be touched with the sealing face of two flanges, so the flanges should have sealing face to match with the flanges face. Commonly,the spectacle flange face should be same with the pipe flanges, it could be raised face(RF), flat face(FF) or ring type joint face(RTJ). The face dimensions should have same specification with the pipe flanges.
Spacer and Spader blind:
The two parts of the spectacle blind flange could be separated to be used,the blind part of the spectacle flange is called spader or paddle, it is used to block the flow fluid in the piping system. The opening part of spectacle flange is called spacer or ring spacer, when it is worked in the two flanges, it will not block the fluid running. Commonly the spader or spacer should have a section of steel handle for control easily.
Red Earth Steels is experienced and professional in the designing and production of the spectacle blind flange, if you have any request for the spectacle blind flange, welcome to contact us for quotation or technical data sheet.