A solid metal spherical disc, having all of the relevant bot holes but no central hole, is usually called a blind flange. These flanges, are usually used to close off the ends of an open piping system, or to create a pressure vessel opening or sometimes to block off an existing pipeline.
Having mounting holes around its perimeter and a gasket sealing ring, it is easily fixed upon the mating surface. Sometimes blind flanges are also used as a divider to stop the flow between two adjacent pipelines. Once fixed, it permits an easy access to the pipe, in case of any work or repair to be done.
Blind flanges come up in various material grades, specifications, and sizes. Apparently, just like the pipe flanges, two types of blind flanges are used:
- Raised face (RF) blind flange
- Flat face (FF) blind flange
Depending upon the height, material, and specifications of the pipeline. They are manufactured in materials like stainless steel, cast iron, aluminum, brass, bronze, plastic, etc, as per the requirement of the pipe. Often it is of the same material as of the pipe. Likewise, standard gaskets or a full face gasket is used to support the flanges to the pipeline, creating a stop, or a pathway for another pipeline to be attached.
Where are blind flanges found mostly?
Commonly in petrochemical industries, pipeline industries, pipe engineering plants, and water plants, these blind pipe flanges are used for high pressure applications. The flange is used for sealing the ends of an open pipe, making it easy to conduct pressure tests. It is also used for making repairs to a pipeline. The blind flange and its bolts are easily stressed more than any other flanges.
And thus, they are used widely in oil and petrol chemical industries, which deals with liquid cargo. The blind flange allows the stream to disconnect without any spillage or loss and permits it extremely safe to work along. Often when a pipeline is constructed, blind flanges are used as a way of expansion, at the end of the length of the pipe, by simply adding a final flange to it, if needed for further purpose.
Uses of blind flanges
The flanges have allowed the art of constructing pipelines to be way more easy, simple, and accessible. Repairing an ongoing pipeline, without stopping the flow, would affect miles of the pipeline as well as its contents. The blind flange makes it possible for the maintenance of the pipeline, by putting a closure at the earlier valve, and making the process hassle free.
It also makes the task of sectional replacement easier. Sections of pipes can be assembled anywhere as per the need with the installation of a blind flange. To stop an unwanted or unused pipe opening, blind flanges are installed. These can also act as the end valve of a large pipeline, in case it needs sealing.
Also used as a blocker between two pipes, this flange also serves the purpose of an extender. Anytime, the pipeline can be extender or cut-off as per the situational needs. Blind flanges very much serve the work of a valve, but in a much easier and cost efficient way.