ASME Blind Flanges

The formal name of blind disk is Flange cover, and some are also called blind flange or pipe plug. It is a flange without a hole in the middle and is used to seal the pipe opening. The function is the same as that of the head and cap, except that the blind seal is a removable sealing device, and the seal of the head is not ready to be opened again. There are many types of sealing surfaces, including plane, convex, concave and convex surface, tenon and groove surface and ring connection surface. The materials are carbon steel, stainless steel, alloy steel, copper, aluminum, PVC and PPR.

From the appearance of the blind plate, it is generally divided into plate type flat blind plate, figure 8 blind plate, plug board, and gasket ring (plug board and gasket ring are blind to each other). The blind plate plays the role of isolation and cutting, and the role of the head, pipe cap and welding plug is the same. Due to its good sealing performance, it is generally used as a reliable means of isolation for systems that require complete isolation. A flat plate blind is a solid circle with a handle that is used in systems that are normally isolated. The figure-8 blind plate is shaped like a figure-8, one end is a blind plate, and the other end is a throttle ring, but the diameter is the same as the diameter of the pipe, and it does not play a throttling role. The figure-8 blind plate is easy to use, when it needs to be isolated, the blind plate end is used, and when normal operation is required, the throttle ring end is used, and it can also be used to fill the installation gap of the blind plate on the pipeline. Another feature is that it is clearly marked and easy to identify the installation status.

Production process

Generally, there are four types: forging, casting and forging, medium plate cutting, and casting. Among them, the price of forging products is the highest, followed by medium plates, and casting and forging is the lowest. Casting is the most advanced process. The quality is good for forging and middle plates, and the casting and forging are slightly worse.

Where the blind plate is applied

1. In the original start-up preparation stage, when the strength test or tightness test of the pipeline cannot be carried out at the same time as the connected equipment (such as turbines, compressors, gasifiers, reactors, etc.), a blind plate should be set at the connection between the equipment and the pipeline.

2. When the device is stopped, if the pipeline is still in operation, a blind plate is set at the shut-off valve.

3. When the device is multi-series, the main pipeline from outside the boundary area is divided into thousands of pipes to enter each series, and a plate is set at the shut-off valve of each sub-pipeline.

4. When the devices need to be regularly maintained, inspected or switched with each other, and the equipment involved needs to be completely isolated, a blind plate is set at the shut-off valve.

5. When the process pipeline of the pressurized pipeline and the displacement gas pipeline (such as nitrogen pipeline and compressed air pipeline) is connected to the equipment, a plate is set at the shut-off valve.

6. If the process medium needs to be concentrated in a unified collection system, a blind plate should be set up behind the shut-off valve.

7. The exhaust pipe, liquid discharge pipe and sampling pipe of equipment and pipeline should be provided with blind plate or plug behind the valve. Except for materials that are non-toxic, non-hazardous to health and non-explosive hazards.

8. When the device is constructed in stages, the interconnected pipelines are set up at the shut-off valve to facilitate the subsequent construction of the project.

9. When the device is in normal production, some auxiliary pipelines that need to be completely cut off should generally be set up with blind plates.