How to use the spade and spacer?
The 8-character blind board gets its name because it looks like an 8-character, and is called spectacle blind. Used to isolate or connect piping systems. The figure-eight blind flange is a steel plate with a fixed thickness divided into two discs. The two disks are connected by flat steel, one of which is a solid disk, and the other is a hollow ring, whose inner hole is consistent with the flange.
Spade and spacer are basically similar to 8-shaped blinds, the difference is that the two are not connected.Spade and spacer are used in piping systems that do not require frequent maintenance, or for large diameter pipes. Depending on the pipe diameter and the pressure rating of the pipe, the blind paddle may weigh several hundred pounds. In order to reduce the unnecessary pipeline load, usually not choose the 8-shaped blind plate, but choose two separate parts, namely spade and spacer.
ASME B16.48 covers pressure temperature ratings, materials, dimensions, tolerances, marking and testing from 1/2 “to 24” pipeline blinds. These pipeline blind plates are used in conjunction with ASME B16.5 flanges. Spectacle blind, spade and spacer are manufactured from steel plates or forgings, and are used under license by ASME B31.3. They usually have the same physical and chemical properties as the supporting flange and pipe materials.