A Detailed Explanation of the Functions, Installation Essentials, and Application Fields of Duct Flanges

 

I. Functions and Structural Characteristics of Duct Flanges

A duct flange (English: Duct Flange) is a flat metal connecting component used to tightly fasten multiple sections of ducts to form a sealed and stable piping system. Its core functions include:

1.Sealing Assurance: Through the cooperation of bolt tightening and sealing gaskets, it effectively prevents the leakage of gases or liquids.

2.Structural Support: It enhances the pressure - bearing capacity of the duct connections, ensuring the stability of the system under high - pressure or vibrating environments.

3.Convenient Maintenance: The modular design facilitates partial disassembly and overhaul, reducing the maintenance cost of the overall system.

 

II. Material Selection and Common Types

Duct flanges usually use metal materials to meet the corrosion - resistance and strength requirements of different scenarios:

-Stainless Steel: Suitable for high - humidity and highly corrosive environments, such as chemical workshops or coastal areas.

-Galvanized Iron Sheet: Economical and practical, widely used in ordinary building ventilation systems.

-Aluminum Alloy: Lightweight and oxidation - resistant, suitable for projects sensitive to weight.

 

According to the connection method and pressure grade, they are mainly divided into the following types:

-Weld - neck Flange: Low in cost, suitable for medium - and low - pressure pipelines.

-Butt - weld Flange: High in weld strength, mostly used in high - pressure or high - temperature systems.

-Common Plate Flange: Integrally formed from duct plates, with high construction efficiency, commonly used for rectangular duct connections.

-Angle Steel Flange: Reinforced with angle steel, used for large - sized ducts with a side length exceeding 2000mm, with better stability.

 

III. Standardized Installation Process and Precautions

1.Pre - installation Preparation:

    - Clean the duct ports, remove burrs and impurities, and ensure the contact surface is flat.

    - Check whether the flange and bolt specifications match to avoid air leakage caused by dimensional errors.

2.Sealing Gasket Installation:

    - Select rubber or silicone gaskets with temperature and corrosion resistance, and place them evenly along the edge of the flange.

    - It is prohibited to reuse aged or deformed gaskets to prevent sealing failure.

3.Flange Alignment and Tightening:

    - Accurately align the two flanges, insert the bolts, and gradually tighten them in a diagonal sequence to avoid uneven stress.

    - Use a torque wrench to control the force and ensure that the bolt pre - tightening force complies with the technical specifications.

4.Quality Acceptance:

    - Detect the parallelism and concentricity of the flanges, and the error should be controlled within ±1mm.

    - Verify the sealing effect through air - tightness tests (such as leak detection with soapy water).

 

IV. Typical Application Scenarios and Industries

Duct flanges play an irreplaceable role in the following fields:

-HVAC (Heating, Ventilation, and Air Conditioning) Systems: Connect supply and return air ducts to ensure the efficiency of indoor air circulation.

-Industrial Waste Gas Treatment: Used for smoke exhaust pipes in chemical plants and power stations, resistant to high temperatures and corrosive gases.

-Clean Rooms: Cooperate with high - efficiency filters to maintain positive - pressure sealing in a dust - free environment.

-Food and Pharmaceutical Industries: Stainless steel flanges are used to meet hygienic standards and anti - pollution requirements.

 

V. Maintenance and Upkeep Specifications

1.Regular Inspections: Check the tightness of the bolts quarterly, and re - tighten or replace broken parts in time.

2.Anti - corrosion Treatment: Spray anti - rust coatings on flanges in humid environments to extend their service life.

3.Emergency Handling: When gasket aging or flange deformation is found, stop the machine to replace the components. It is strictly prohibited to operate with faults.

 

Through scientific selection, standardized installation, and systematic maintenance, duct flanges can significantly improve the reliability of piping systems, reduce operation and maintenance risks, and are indispensable key components in the construction and industrial fields.