blind flange

What is blind flange?

Blind flange is one of the most practical high pressure connections used in popping. Blind flange is used to block fluid flow along lines and equipment. This type of connection is made according to customer needs in different dimensions and sizes. In the future, stay with Alborz Part Jahan to learn more about blind flanges, structure and more. . . know.

Blind flange structure

Blind flange, as its name suggests, is used to temporarily or permanently block the passage of fluids in popping. This flange is called BL for short. This piece, like other flanges, is a circular disc-shaped plate with holes around it. Its structure is such that there is no place for fluids to pass. As a result, using it leads to blocking the path. Like other flanges, the blind flange is connected to other flanges by means of bolts and nuts through the holes built around it. Also, a gasket washer is used between two flanges to prevent leakage of passing fluid.

Technical specifications and application of blind flange

Blind flange is used to block the end of the work or the nozzles of the tanks. In addition to blocking, this type of flange is also used in pressure testing. It is not bad to know that due to the blocking property of this type of flange, more pressure is exerted on the blind flange than other flanges. Also, the tension in the blind flange is higher in its center than in other places. These points show its high status against pressures and tensions. The blind flange production standard is ASME B16.5.

Application

The blind flange is actually one of the most important industrial connections, especially during piping route repairs. Imagine that we need to temporarily stop the fluid flow to repair a part of the pipes. Or looking to add a valve in the middle of the pipeline. In any case, we must use a blind flange to temporarily stop the fluid flow. Therefore, it can be said that the use of this piece makes work and industrial operations easier. With these explanations, it seems that the application of the blind flange is as follows:

Block a pipeline
Part of piping repairs
Pipeline expansion

It is important to remember that the use of blind flanges in various industries is of considerable importance. But to use a blind flange, you will also need a throat flange. Because it is not possible to use blind flange alone.

Types of blind flanges

Blind flanges are produced according to the needs of the customer and the place of use. Alborz Part Jahan company also produces different types of blind flanges with high quality and in different pressure classes.

Therefore, blind flange types are divided as follows:

metallic
Carbon steel
cast iron

Among all these cases, the carbon steel blind flange is one of the most widely used flanges. It is not bad to know that iron (cast iron) flanges are also used in pipelines with low pressures.

Also, the blind flange is divided into three models based on the surface:

Smooth surfaces
Raised surfaces
Grooved

In the following, we will describe the details of blind flange types:

Blind steel flange

Blind steel flange is produced from the best raw materials according to the standards of the world. A steel disk-like plate used to block the passage of liquids. One of the most important advantages of this high pressure steel piece is its relatively high pressure tolerance.

Carbon steel blind flange

Carbon steel blind flange is one of the most widely used types in the important petrochemical industries of oil and gas, water and sewage, etc. . . is used In terms of the material used in its construction, carbon steel is under more pressure than other flanges. For this reason, in the carbon steel flange, the stress value is selected more than other blind flanges. This flange is available in gold, black and silver colors.

Cast iron blind flange

Cast iron blind flange or iron blind flange is another type of blind flange in terms of its material. The working pressure in these flanges is 10 atmospheres.

Blind flange standards

As we mentioned above, the blind flange is made according to the customer’s needs. But the basis of production is in accordance with global standards. For example, blind flanges can be produced and marketed based on standard dimensions from 1.2 inches to 120 inches. Therefore, you will not have a problem in meeting your needs when buying a blind flange. Also, this piece is divided into different classes based on pressure and temperature. But it is not bad to know that the blind flange can withstand pressure up to twice the nominal class in which it is located.

ASNI and DIN standards are considered for blind flange classification.

Dimensional standard

Blind flanges are produced based on standard dimensions from 1.2 to 24 inches. This production is based on ASME B16.5 standard. It is produced in dimensions of 26 inches and above in two Aseries and Bseries models and is based on the ASTM A182 standard.

Class 150 blind flange

Blind flange 150 is produced from 1.2 to 24 mm in diameter and from 9.6 to 1.46 mm in thickness. Also, class 150 is made from 0.9 kg to 196 kg, and in class 150, the number of screws is from 4 to 20. Read more about class 150 blind flange here.

Class 300 blind flange

In blind flange 300, the nominal diameter of pipes can be produced from 1.2 to 24. In this class, the flange thickness ranges from 7/12 in the lowest diameter to 3/68 in the highest diameter. Also, the number of screws in class 300 blind flange starts from 4 and reaches 24. The weight of class 300 starts from 1.4 kg and reaches up to 359 kg in blind flange 300 with a nominal pipe diameter of 24. Learn more about class 300 blind flange here.

Class 600 blind flange

The nominal diameter of class 600 blind flange is 1.2 to 24, like 300 and 150 blind flange. The thickness of this piece in class 600 is the same as blind flange 300.

Advantages of blind flange

As we briefly mentioned above, the use of blind flanges has several advantages for piping. In summary, the advantages of blind flange can be as follows:

Ease of operation
Ability to repair
Long life
High pressure resistance
High heat resistance
Ability to open and close along the pipeline route
Method of production

The blind flange is produced in two ways, which are:

Casting

In this method, molten steel is poured into a mold and after forming, drilling, turning and painting are done on it.

forge

In this method, the blind flange is heated through a steel piece and reaches the melting point. Then it is made into one piece using the matrix process.