Blind flanges: What they are and what they are used for

The purposes and needs of different engineering projects dictate the designs of the different types of existing flanges. They exist mainly to join up various components of a piping system, and to facilitate the cleaning, inspection and modification of the pipeline. In this post, we will tell you everything you need to know about blind flanges.

What are blind flanges?

Blind flanges are circular pieces with the usual bolt holes around the perimeter, but their defining characteristic is that they do not have the usual hole through the center. As they are “blind” (solid), they totally block the flow of a line and allow easy access to the interior of the line when it has been closed and needs to be reopened.

Another feature is that they can withstand more extreme conditions than other flanges. They are often used when the temperature or the type of product at the closures is an important factor, or where there might also be variable or cyclical forces applied.

The composition of the flanges can differ, always depending on the environmental conditions and stress that they will need to withstand.

  • Carbon steels, for moderate temperatures
  • Alloy steels, to withstand extreme temperatures and pressure
  • Nickel, chromium and molybdenum, when the material is in contact with corrosive liquids or gases

What are blind flanges used for?

Their use and characteristics are very specific and different from those of other flanges.  Blind flanges are designed to close and seal off the ends of pipes or pressure vessels. They are mainly used in high pressure applications, to prevent the flow of liquid or gases.

From a technical point of view, this type of flange, particularly if large in size, needs to withstand much more severe working conditions since the stress caused by the traction of the bolts is added to that produced by the pressure in the pipe itself.

For this type of flange, specialists recommend that the line be closed by coupling together collared and blind flanges.

Application of blind flanges in industry

Blind flanges have multiple uses in industry and are becoming increasingly popular because of their safety and reliability in sealing pipes.

Among the industries where they are most popular are petrochemicals, solar plants, pharmaceuticals, food and wastewater treatment.

Forged flanges from ULMA Advanced Forged Solutions

At ULMA Advanced Forged Solutions you will find a wide variety of forged flanges. If you dive into our catalog you will see parts with a huge range of sizes (from 1/2 to 102 inches), different pressure ranges, and many different alloys.

Each engineering project has very specific needs. Therefore, although we have a wide variety of parts, we also design, calculate and produce custom-made flanges based on the specific needs of each situation.

All the forged flanges from ULMA Advanced Forged Solutions follow ASME B16, ASME B16.47 or MSS SP-44 standards, so their functionality is guaranteed and replacement is made easier when necessary.