1. Definition of long high neck flange

Long high neck flange refers to a type of flange whose flange neck is longer than that of ordinary flange. This long neck is usually used to strengthen the connection between the flange and the pipe to prevent deformation or leakage at the flange connection due to internal pressure or external force.

2. Structural characteristics of long high neck flange

Long high neck flange has the following main structural characteristics:

Long neck: Compared with standard flanges, the flange neck of long high neck flange is significantly longer. The function of the long neck is to strengthen the connection between the flange and the pipe, especially for occasions that need to withstand higher pressure or temperature.

Flange: Similar to ordinary flanges, there are multiple holes on the flange for bolting other flanges or pipeline components.

Sealing surface: The sealing surface part of the flange adopts different sealing designs, such as flat seal, convex seal or other forms, to ensure that there is no leakage at the connection.

Strengthened design: Due to the long high neck design, the overall strength of the flange is higher and can withstand greater pressure and mechanical loads.

3. Technical parameters

4. Advantages of long high neck flange

Enhance strength and stability: The long high neck design provides better support and bearing capacity, suitable for high-pressure and high-temperature pipeline systems, and avoids leakage due to uneven force on the pipeline.

Improve sealing performance: The long high neck flange can better avoid leakage caused by high pressure or vibration, and is suitable for high-pressure fluid and gas transmission.

Adapt to complex working conditions: In some special working conditions, the long high neck flange can reduce stress concentration and increase the durability of the connection part.

Corrosion resistance and high temperature resistance: Depending on the material, the long high neck flange can choose high temperature resistant and corrosion resistant materials to meet various industrial needs.

5. Application of long high neck flange

Long high neck flange is suitable for fluid systems with high pressure, high temperature or strong corrosiveness. Common applications include:

Oil and gas industry: Long high neck flange is often used in oil and natural gas transportation pipelines, which withstand high pressure and harsh environmental conditions.

Chemical industry: Used in high temperature and high pressure chemical reaction pipelines to prevent corrosion and leakage.

Nuclear and power industry: In the pipeline systems of nuclear power and power stations, the high strength and high temperature resistance of the long high neck flange meet these special needs.

Marine engineering: Suitable for pipeline connections on offshore platforms, which can effectively cope with corrosion and extreme temperatures in marine environments.

6. Common standards for long high neck flanges

Long high neck flanges can be divided into many types according to international standards. Common standards include:

ANSI B16.5: Applicable to American national standards, suitable for long high neck flanges with pressure levels of 150LB, 300LB, 600LB, etc.

DIN 2630/2631: Applicable to high neck flanges of German DIN standards, commonly used for industrial pipeline connections.

JIS B2220: Applicable to long high neck flanges of Japanese standards, widely used in domestic industrial systems in Japan.

ASME B16.47: Applicable to large long high neck flanges, commonly used for large-sized high-pressure pipelines.

7. Material of long high neck flanges

The material of long high neck flanges is usually selected according to different application scenarios. Common materials include:

Carbon steel: Suitable for regular working environments and occasions with medium pressure requirements, such as 150LB, 300LB and other pressure levels in the ANSI standard.

Stainless steel: For environments that require higher corrosion resistance and high temperature resistance, such as chemical industry, marine engineering and other occasions, stainless steel materials are usually selected.

Alloy steel: Suitable for extreme environments, such as special working conditions such as high temperature and high pressure. Alloy steel has good mechanical properties and corrosion resistance.

8. Installation of long high neck flange

The installation steps of long high neck flange are similar to those of ordinary flanges, but due to its special long neck design, the following points should be noted during installation:

Pipeline preparation: Make sure the pipe end is flat, the sealing surface is not damaged, and the inside and outside of the pipe are clean.

Flange matching: Select a long high neck flange of appropriate size and pressure level to ensure that the flange matches the pipe.

Installing the flange: Align the flange with the end of the pipe to ensure that the flange sealing surface is in good contact.

Tightening the bolts: Tighten the bolts with appropriate tools to ensure that the flange connection is stable and avoid loosening or leakage.

9. Precautions for long high neck flanges

Sealing check: After installation, be sure to check the sealing of the flange connection to ensure there is no leakage.

Force distribution: The design of the long high neck flange can provide better force distribution, but it is still necessary to pay attention to the impact of pressure and temperature changes on the flange under high pressure environment.

Material selection: Select the appropriate material according to the medium and working environment transported by the pipeline to prevent failure due to corrosion or fatigue.

Regular inspection and maintenance: Regularly inspect the long high neck flange, especially in high temperature and high pressure systems, to ensure the reliability of the flange connection.

10. Summary:

The long high neck flange, with its unique design, provides stronger support and sealing than ordinary flanges, and is widely used in high pressure, high temperature, and highly corrosive pipeline systems. Selecting the appropriate standards, materials and installation methods is the key to ensuring the long high neck flange's long-term reliable operation.