The "8" type blind plate is named because it looks like an "8" type blind plate. Used to isolate or connect piping systems. The spectacle blind is a steel plate with fixed thickness divided into two discs. Two discs are connected by flat steel, one of which is a solid disc, the other is a hollow ring, and its inner diameter is the same as that of the flange.
The spectacle blind is a kind of pipe part, which is mainly used to facilitate maintenance. For specific shape, you can paint the upper part of "8" black. It is half blind plate and half iron ring. It is commonly used for pipeline flanges that need to change the process. The materials mainly include carbon steel, stainless steel and alloy, which can be selected according to the pipeline pressure grade and pipeline medium.
The spectacle blind is usually required to be isolated from other facilities or devices in the pipeline system. Normally, the spectacle blind is in the open position so that the fluid can pass through the pipe. When the spectacle blind is in the closed position, the pipe is closed and the fluid is blocked.
The maintenance of the piping system was one of the reasons why the spectacle blind was rotated to the closed position. There is a drill hole in the connecting web of the spectacle blind plate. Loosen and disassemble some bolts. The spectacle blind plate can rotate between flanges. After the gasket is replaced, the bolts can be reassembled and fastened.
Meaning: It is usually used on pipelines with large pipe diameters. At ordinary times, one end of the flange occupies the space to keep the pipeline unblocked. If necessary, it is replaced with a blind plate with the same thickness at the other end to cut off the pipeline. Avoid the forced expansion of pipelines due to temporary replacement of other blind plates, which will affect the whole system.