Spectacle Blind Flange

QS Flange: Xiame Spectacle Blind Flange

Spectacle blind flange per ASME B16.48 and API 590, 1/2 to 56 inch, Class 150-2500, FF/RF, in carbon, stainless, alloy and duplex steel for line isolation.

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One-Minute Overview

Figure-8 plate that switches a flange joint between open and fully blocked.
One end is a solid blind, the other an open ring, joined by a steel web.
ASME B16.48 and API 590, sizes 1/2 to 56 inch, Class 150 to 2500.
FF or RF faces in carbon, stainless, alloy and duplex steel.

A spectacle blind flange lets operators change a flange joint from open to blocked without breaking the bolting twice: the figure-8 plate is swung so either the solid blind or the open ring sits between the flange faces. This series is dimensioned to ASME B16.48 and API 590, covering sizes 1/2 to 56 inch and pressure classes 150 to 2500.

Name: Spectacle Blind Flange
Size: 1/2"-56"
Pressure: Class 150 - Class 2500
Flange Face: FF/RF
Material: Carbon Steel, Stainless Steel, Alloy Steel, Duplex Steel
Standard: ASME, ANSI B16.48, API 590

Use the solid end when the section must be positively isolated for maintenance or tie-in work; swing to the open end when the line returns to service. FF and RF faces cover the usual gasket arrangements, and carbon, stainless, alloy or duplex bodies let the blind match the pipe metallurgy. Spectacle blinds are common in oil, gas and petrochemical piping where sections are opened at each shutdown.

FAQ

Q1. What standards does this spectacle blind follow?

The figure-8 plate is dimensioned to ASME B16.48 and API 590, covering sizes from 1/2 to 56 inch and pressure classes from Class 150 to Class 2500. Those standards fix the plate geometry and clearances, so the blind swings freely between standard flange faces of the matching size and class.

Q2. So how does the open-and-shut trick actually work?

The plate is a figure-8: one end is a solid blind, the other an open ring, joined by a steel web. Swing the solid end between the flange faces and the line is positively blocked; swing the open ring in and flow resumes. The bolting is broken once, not twice as with a plain blind.

Q3. When should the solid end face the line?

Use the solid end whenever the section must be positively isolated — maintenance, tie-in work, or any job where probably closed is not good enough. Swing to the open end when the line returns to service. The visible plate position also tells everyone on site at a glance whether that section is open or blocked.

Q4. What payment terms do you accept?

T/T, L/C at sight and other internationally accepted terms. The exact terms are agreed with you before production starts, because the payment schedule has to match the order value, the shipping method and the delivery schedule you need — which is also why we confirm them up front rather than after shipment.

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