Spectacle Blind Flange Figure 8 flange

A Spectacle Blind Flange(also called Figure 8 flange) is a pressure-retaining
plate with one solid end and one open end connected with a web or tie bar.
Size: 1/2″ to 96″
Pressure class: Class 150 to Class 2,500, PN 2.5 to PN 250
Facing: RF / RTJ

Spectacle flanges, also known as spectacle blind flanges or Figure 8 flanges,
are most commonly used on piping systems that need to be separated regularly or
where the flow through the systems is regularly stopped. One end of the
spectacle flange is solid, while the other end has a hole in the center. The
spectacle flange can be rotated to place either the solid or hollow end within
the pipe system, thereby opening or closing the flow.

Spectacle blind flanges types:
There are three types of spectacle blinds:
1. Flat face spectacle blind (FF) flange
Similar to a flat face flange, the surface of the disc is flat (suited for flat
face gaskets, for low-pressure applications).

2. Raised face spectacle blind (RF) flange
likewise raised face flanges, there is an additional thickness on the surface
of the disc. This type fits semi-metallic gaskets, as the spiral wound type.

3. Ring joint face spectacle blind (RTJ) flange
a groove is inscribed on the surface of the disc. This type is used in
conjunction with ring joint gaskets.

Functions: Blind flange VS. spectacle blind flange

The function of the blind flange is the same as that of the head and the pipe
cap, except that the seal of the blind plate is a detachable sealing device,
and the seal of the head is not ready to be opened again. There are many types
of sealing surfaces, including plane, convex, concave, convex, mortise and
groove surfaces, and ring connection surfaces. Materials are carbon steel,
stainless steel, alloy steel, copper, aluminum, PVC, and PPR.


The spectacle blind plate is commonly used for the pipeline flange, which needs
to change the process. The material mainly includes carbon steel, stainless
steel, and alloy. It can be selected according to the pipeline pressure grade
and pipeline medium.

Minimum Order: 10 sets

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