• Size Range: 15mm- 1500mm (1/2”- 60”) Ratings 150lb-2500lb as per ASME B16.48 (other standards available)
• Sealing Type: Flat Face, Raised Face, Ring Joint
• Sealing Finish: Spiral Finish 3.2-6.3ra for facings
• Materials: A516 GR70, AS1548 –PT460 (NR), A105, LF2, 304/304L, 316/316L, UNS31803. Other materials on request
• Many sizes ex stock. Custom items: usually 10-20 days.
• Also called: Fig 8 blinds, Spectacle Blanks, Line Blinds

A Spectacle Blind is essentially a simplistic valve which fits in the line between two flanges and is bolted in place. One side of the Spectacle Blind is open (spacer) and the other side of the spectacle blind is blanked (blind or spade).

In the process of changing it from open to closed, all except the pivot bolt are removed and the spectacle blind is rotated on its centre hole so the blind side is in between the flanges. The bolts are then installed again and tightened. The side that hangs out of the pipe is a clear indicator of whether the pipe is open or closed.

A Spectacle Blind is used usually for maintenance when it is required to isolate a section of pipe or isolate a device.  As this is a semi-permanent isolation, it is very safe and safety is often the mentality behind a spectacle blind use in maintenance operations. Compared to a valve they are cheap and robust.

Spectacle Blind Stamping

Typically a Spectacle Blind will have the size, rating, standard, material, heat number, production traceability code and the Caman Engineering Stamp stamped on it. 

We have found that many clients ask to have their own part identification and process traceability stamped on the Spectacle Blind.

Spectacle Blind Standards

The most common standard is ASME B16.48 which provides dimensions to suit ASME B16.5 flanges.  A range of international standards and specific custom drawings dictates the specifications around Spectacle Blinds.  

Spectacle Blinds Sealing Facings

Typically, Spectacle Blinds are produced as a flat face, raised face or ring joint sealing surface depending on the application requirement. The spiral sealing face is a specified finish typically Ra 3.2µm-6.3µm.

Spectacle Blind Materials

As an Australian manufacturer, Caman Engineering are able to manufacture the Spectacle Blinds in a material with the testing as required by the client specification. Typically, Spectacle Blinds will be manufactured from carbon or stainless steels. Typical carbon steel materials are AS1548 460NR, A516 Gr70 or forgings like A105, A350 LF2, A350 LF3. Corrosion resistant materials A240 P316L, A240 P304L, UNS31803 are common. Less common but easily supplied is Super Duplex 2205 and Incoloy 625.

Additionally, we have available specialist finishes such as galvanising, PTFE coatings and linings and various epoxy finishes.

Corrosion Protection and Packaging

A Spectacle Blind will always have 4 sealing faces and this requires significant sealing face protection.

Whether you want the Spectacle Blind protected for 2 weeks or 2 years, Caman Engineering have packing system that ensures that spectacle blinds arrive at the installation in good condition.

We are able to provide even more robust corrosion protection upon request.

Special Spectacle Blinds

Sometimes a specific engineering requirement may dictate the need for special material and construction required to produce the Spectacle Blind. Caman Engineering are a manufacturer with full ISO 9001 certification and are able to produce to your requirements including detailed testing and documentation. All material is traced through the system and ITPs and MDRs are available on request. Your Spectacle Blinds can be packaged according to your engineering or project specification and all this can be done with remarkably short delivery times.