What are the classification, production processes and applications of blind flanges?

The blind plate is mainly used to completely isolate the production medium to prevent the lax closing of the shut-off valve from affecting production or even causing accidents. The blind plate should be installed in the parts that require isolation, such as the equipment connection port, the front and rear of the shut-off valve, or between two flanges. It is often recommended to use an 8-shaped blind plate; inserts can also be used for one-time use parts such as pressing and purging. Plate (round blind plate).

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The function and classification of blind plates

From the appearance point of view, blind plates are generally divided into flat plate blind plates, figure 8 blind plates, insert plates, and gasket rings (the insert plates and gasket rings are blind to each other). The blind plate plays the role of isolation and cutting, which is the same as the function of the head, pipe cap and welding plug. Due to its good sealing performance, it is generally used as a reliable isolation method for systems that require complete isolation. The plate blind plate is a solid circle with a handle, which is used for 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 throttling ring, but the diameter is the same as the diameter of the pipe and does not play a throttling role. The figure 8 blind plate is easy to use. When isolation is required, use the blind plate end. When normal operation is required, use the throttle ring end. It can also be used to fill the installation gap of the blind plate on the pipeline. Another feature is that the markings are obvious, making it easy to identify the installation status.

Production Process:

Generally divided into four types: forging, casting and forging, medium plate cutting, and casting. Among them, forged products have the highest price, followed by medium plates, and cast and forged products have the lowest price. Casting is the last craft. The quality is better for forged and medium plates, but slightly worse for cast and forged ones.

Application parts:
1. In the initial 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.), the equipment must be A blind plate is provided at the connection with the pipe.
2. For various process material pipelines outside the boundary area that are connected to the boundary area, when the device is stopped, if the pipeline is still running, a blind plate should be installed at the cut-off valve.
3. When the installation is multi-series, the main pipeline from outside the boundary area is divided into thousands of pipes entering each series, and blind plates are installed at the cut-off valves of each branch pipe.
4. When the device needs to be regularly maintained, inspected or switched between each other, and when the equipment involved needs to be completely isolated, a blind plate should be installed at the cut-off valve.
5. When pressurized pipelines, replacement gas pipelines (such as nitrogen pipelines, compressed air pipelines) and process pipelines are connected to equipment, a blind plate is installed at the cut-off valve.
6. Drain the low points of equipment and pipelines. If the process medium needs to be concentrated into a unified collection system, set a blind plate after the cut-off valve.
7. The exhaust pipes, drain pipes, and sampling pipes of equipment and pipelines should be equipped with blind plates or plugs after the valves. Materials that are non-toxic, non-hazardous to health and non-explosive hazards are excluded.
8. When the device is constructed in phases, a backing plate should be installed at the cut-off valve for interconnected pipelines to facilitate subsequent construction.
9. When the device is in normal production, some auxiliary pipes that need to be completely cut off should generally be equipped with blind plates.

Maria Yang

Post time: Jan-26-2024