Spectacle Blind Thickness
Spectacle blinds should be made from a plate or forging specification approved for use by asme b31 3 of essentially the same chemical composition as the mating flanges and piping involved.
Spectacle blind thickness. The thickness of the spectacle blind is specified based on the line pressure and pipe size. Spectacle blinds are generally applied to permanently separating pipesystems or just to connect with each other. Asme b16 48 standard that covers line blanks.
The two discs are attached to each other by section of steel similar to the nose piece of a pair of glasses. Click on the link to learn about the chemical and mechanical properties and the selection criteria of these common spectacle blind grades which are the same as. A spectacle blind is used in piping for positive isolation of the section of a line or equipment during maintenance and shutdown.
A line blank conforming to this standard will be marked in the following way. The specification that determines the dimensions of a spectacle blinds is asme b16 48 line blanks. A spectacle blind is a steel plate cut into two discs of a certain thickness.
Spectacle blind spades and spacers are also known as figure 8 paddle blank slip blind and spacer. Mixed material joints asme b16 48 specifies that should either the two flanges or the line blank in a flanged line blank assembly not have the same pressure temperature rating the rating of the assembled joint at any temperature shall be the lower of the flange or line blank rating at that temperature. These are three different components that used in piping for positive isolation of the section of a line or equipment during maintenance and shutdown.
The two discs are attached to each other by section of steel similar to the nose piece of a pair of glasses. In practice these dimensions have been rounded round off upwards. An 8 blind or a spectacle blind is a piping fitting that is used for providing positive isolation.
A spectacle blind is a steel plate cut into two discs of a certain thickness. Wt thickness of the web or tie bar should be 6 mm minimum or equal to thickness t if less than 6 mm. One is solid disc and the other is hollowed.
Nominal pipe size nps. Spectacle blinds are available in standard sizes up to 24 inches and in forged material grades like astm a105 high temperature carbon a350 low temperature carbon and various astm a182 grades alloy stainless steel duplex. A spectacle blind is basically made up of two metal discs attached to each other by a metal strip as shown in the figure.
