Sometimes events defy logic, and you just have to go with the flow.

We noticed recently that our video of a spectacle blind was hugely popular on our YouTube Video Channel.

It’s a cool video, but apparently more interesting than even we realised. Sure Flow Equipment sells lots of these, so it never hurts to ‘go with the flow’ (which is appropriate in the strainer business) and do a review of this product line which includes spectacle blinds, paddle blinds and paddle spacers.

spectacle blind paddle blind and paddle spacer

Spectacle Blinds

spectacle blind is a simple safety device that installs between two pipe flanges. During normal operation the open end is installed as a spacer to allow uninterrupted flow. To stop the flow in the pipeline, the blind end is rotated into place between the flanges. This positively isolates the downstream piping and equipment.

Spectacle Blinds are generally installed as a permanent device. Having one end open and one end closed gives a quick visual indication to its orientation and whether or not it is safe to begin downstream work. If you can see the closed half, it means the half that is active in the pipeline is allowing fluids through. If the open side is visible it means fluids are not flowing through.

12 inch spectacle blind

Paddle Blinds

Paddle Blind is basically the solid half of a Spectacle Blind. A Paddle Blind is often made from one solid metal disc and will usually have a thin length of metal attached to one end to be used as a handle. A finished assembly will resemble the shape of a paddle, hence the name. Generally, these types of blinds are applied in piping systems that do not require constant maintenance. The Paddle Blind is used more as a temporary blocking device to stop flow in a process piping system.

paddle blind

Paddle Spacer

A Paddle Spacer is the open half of a Spectacle Blind. It is often made from one solid metal disc and will usually have a thin length of metal attached to one end to be used as a handle. A finished assembly will resemble the shape of a paddle with an opening through its center. The Paddle Spacer is used in place of a Paddle Blind when the piping system is to be put back into operation.

paddle spacer

Sure Flow Line Blinds thicknesses are based on ASME B16.48 specifications and are designed to withstand any pressure – temperature combination that an ASME flange will withstand.

For Paddle Spacers, the hole diameter in the handle is 1/2” for 1” wide handles, and 3/4” for 1 1/2” wide handles. ASME B16.48 prohibits the use of indicator or bolt holes in the handles of Paddle Blinds. However, this option is available if required by purchaser.

On Sure Flow Line Blinds one coat of standard shop primer will be applied to all carbon steel Line Blinds unless specified differently. Mill finish is standard but other surface finishes are available.

Standard materials for our line blinds are SA516 Gr.70, 304 Stainless Steel, or 316 Stainless Steel.  Other alloys can be furnished upon request.

Sure Flow Equipment Line Blinds are produced in strict accordance with the following codes of practice: ASME B16.48 • ASME B16.5 • ASME B16.20 • ASME B16.47 (For larger diameter flanges)

Obviously with these many options in materials and sizes, it’s always good to give us a bit of a heads up if you think you may require some of these for an upcoming project.

Since we hyped how popular the spectacle blind video is, we’d thought we should provide the link. It’s at the bottom this page.