The blind flange is a kind of flange widely used in piping applications. This blog will cover the basic definition of blind flanges, how it works, how to measure them, etc.
In plumbing, a blind flange is a type of flange that is used to block off the end of a pipe. Blind flanges are not used with pipes that have been cut to length, but instead, they are welded onto the end of a pipe that has been extruded or cast.
After the blind flange has been welded, it is machined to create a smooth, finished surface. Blind flanges are used in various applications, including food, chemical, and water treatment. While they are available in different sizes and material grades, the most common blind flange is made from carbon steel.
Now we know the basic definition of a blind flange. Many people may ask how many types of blind flanges are there. In fact, the most commonly used ones are raised face(RF) or flat face (FF).
If the flange is RF, it is typically recommended to use a standard ring gasket. However, if the flange is FF, it is usually best to use a full face gasket, as the flat surface can better resist the bending forces that can occur when using a ring gasket or RF flange against an FF flange.
In addition, it is important to note that blind flanges are not designed to be opened and closed like traditional pipe flanges. As such, they should only be used in applications requiring a permanent connection.
Why is it called a blind flange?
A blind flange is a type of flange that is used to seal the end of a pipeline. It is called a “blind” flange because it does not have a hole in the center, which allows it to be welded shut.
Blind flanges are often used in situations where the flow of fluid needs to be stopped or redirected, such as at the end of a pipeline or in an emergency situation. They are also used to seal off the ends of pressure vessels and storage tanks. Blind flanges are available in a variety of materials, including stainless steel, carbon steel, and aluminum.
How does a blind flange work?
As we mentioned previously, a blind flange is a type of pipe flange that is used to seal off the end of a piping system. It is designed to be bolted onto the end of a pipeline and has a raised face that helps prevent leaks.
Blind flanges are also used when it is impossible to attach a screw-on type of flange, such as when two pipes need to be joined in an offset configuration. In order to install a blind flange, the pipes must first be cut to the correct length and then cleaned so that there is no debris present.
The blind flange is then placed over the end of the pipe and bolted into place. Once installed, the blind flange will provide a tight seal that will help to prevent leaks.
Does a blind flange need a gasket?
In general, it is recommended to use a gasket for blind flanges. Blind flanges are often used in high-pressure applications, so the gasket must be able to withstand extreme temperatures and pressures. In addition, the gasket must be able to form a seal against the surface of the flange, without leaking.
For these reasons, it is generally best to use a standard gasket for blind flanges. Standard gaskets are made from a variety of materials, including asbestos, PTFE, and rubber.
Asbestos gaskets are particularly well-suited for high-pressure applications, but they can be difficult to work with and are not always safe to use. PTFE gaskets are less durable than asbestos gaskets, but they are easier to work with and are safer to use.
Rubber gaskets are the most common type of gasket used in blind flanges, as they are durable and easy to work with. However, rubber gaskets are not suitable for all applications, so it is important to choose the right material for the job.
What is the difference between blank flange and blind flange?
People sometimes are confused by blank flange and blind flange. In general, both the blank flange and blind flange serve the same purpose of blocking off the end of a pipe, but they differ in terms of thickness and design.
A blank flange is a thin plate slipped between pipe flanges in a pipeline. This type of flange is often used when repairing or modifying a pipeline since it is relatively easy to install and remove. In contrast, a blind flange is thick with bolt holes but no hole in the middle.
This type of flange is typically used to permanently seal off the end of a pipe. Blind flanges are more difficult to install than blank flanges but provide a more secure seal.
How do you measure a blind flange?
There are a few different ways to measure a blind flange.
- The first is to measure the inside diameter (ID) of the flange. This is the distance from the inside edge of the flange to the center of the bolt hole.
- The second way to measure a blind flange is to measure the outside diameter (OD) of the flange. This is the distance from the outside edge of the flange to the center of the bolt hole.
- Finally, you can measure the thickness of the flange. This is the distance from the top of the flange to the bottom of the bolt hole.
Summary
A blind flange is a type of pipe fitting that allows you to connect two pipes without having to weld them together. This can be helpful if you need to make changes or repairs to the piping system later on. The fittings are also relatively easy to use, so they’re a good option for inexperienced pipefitters.
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