Flange blind plate is also called blind flange, real name blind plate. It's a connection form of a flange. One of its functions is to block the end of the pipeline, and the other is to facilitate the removal of debris in the pipeline during maintenance. As far as the sealing effect is concerned, it has the same effect as the head and tube cap. But there is no way to disassemble the head, and the flange blind plate is fixed with bolts, very convenient disassembly. Flange blind plate quality is carbon steel, alloy steel, stainless steel, plastic and so on. The flange blind plate is used to seal the end of the pipeline, including the welded flange blind plate and the flange cover (the flange cover is bolted). The flange cover is the flange blind plate, and the flange blind plate is not only the flange cover form, but also the welded flange blind plate, the clamping flange blind plate and so on.

In the design of flange blind flange, there are several key points that need to be paid attention to in the design: reasonable design of flange, that is, proper design of alloy flange cone neck and flange ring ratio, make the flange torque as small as possible, in order to reduce the stress index of the flange; According to the working condition, reasonable selection of gasket material and reasonable design of gasket width, reduce the bolt preload and operating force; Reasonable selection of bolt material, bolt diameter and bolt number, and the value of bolt center circle diameter as small as possible; Reasonable selection of flange materials, flange overall design should be as far as possible to achieve full stress design, to achieve both safety and cost saving purposes.
With the rapid development of domestic pipeline construction, pipeline pressure test has become an essential link. Before and after pressure test, each section of pipeline must be swept by the ball, the number of times is generally 4 ~ 5. Especially after pressure test, it is difficult to clean the water stored in the pipeline, so the cleaning times will be more.