Spectacle Blind

QS Flange: Jiaxing Spectacle Blind

A516 Gr.70 spectacle blind per ASME B16.48, 1/2 to 24 inch, Class 150-2500 LB, RF/FF, for positive isolation of piping sections.

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One-Minute Overview

Figure-8 isolation plate rolled from A516 Gr.70 pressure vessel steel plate.
ASME B16.48 dimensions, 1/2 to 24 inch, Class 150 to 2500 LB.
RF or FF faces to match the mating flange gasket arrangement.
Swing between the solid blind and the open ring at each shutdown.

This spectacle blind is cut and rolled from A516 Gr.70 plate, a carbon steel grade used for pressure vessel and structural plate work. The figure-8 shape joins a solid blind end to an open ring end with a steel web, so the line can be switched between blocked and open simply by swinging the plate between the flange faces.

Name: Spectacle Blind
Material: A516 GR.70+S5
Manufacture Standard: ASME B16.48
Face: RF/FF
Size: 1/2 to 24 inch
Class: 150 to 2500 LB

Dimensions follow ASME B16.48 so the blind drops into standard flange joints across the 1/2 to 24 inch range. RF and FF faces cover both raised-face steel flanges and flat-face joints. Spectacle blinds give a visible, positive isolation point for maintenance and tie-in work in oil, gas and petrochemical piping.

FAQ

Q1. Why is A516 Gr.70 plate used for this spectacle blind?

A516 Gr.70 is a carbon steel grade used for pressure vessel and structural plate work, so the rolled plate keeps the toughness a repeatedly swung isolation plate needs. The figure-8 is cut and rolled from that plate, with the solid blind end and the open ring end joined by a steel web.

Q2. How does it make shutdown isolation easier?

Swing the plate between the flange faces and the line is blocked; swing it back and the line is open. The position is visible from the floor, so every shutdown gets a positive isolation point you can point at — no guessing whether that spool is really empty before the crew opens it.

Q3. Which face should I choose, RF or FF?

Match the mating flange gasket arrangement: RF faces cover raised-face steel flanges and FF faces cover flat-face joints. The plate itself follows ASME B16.48 across 1/2 to 24 inch and Class 150 to 2500 LB, so the face choice is really about the gasket scheme of the joint it drops into.

Q4. What's the smallest order I can place?

Standard flange insulation gasket kits start at one set, and standard gaskets, studs, washers and sleeves start at one piece. Blinds cut to your drawing or to a non-standard size are quoted individually, because the minimum really depends on the material and the tooling involved.

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