Trong hệ thống đường ống công nghiệp, mặt bích đường kính lớn are critical components that enable the connection of oversized pipes, van, tàu thuyền, và thiết bị. Những mặt bích này được sử dụng phổ biến trong các nhà máy điện, cơ sở xử lý hóa chất, nhà máy lọc dầu, nhà máy xử lý nước, nền tảng ngoài khơi, and large-scale infrastructure. Due to their size, cân nặng, and operating conditions, cái assembly of large diameter flanges involves more complexity and higher safety requirements than standard flange connections.

This article explains the principle requirements for large diameter flange assembly, including preparation, căn chỉnh, điều khiển mô-men xoắn, niêm phong toàn vẹn, safety precautions, và kiểm tra. Whether you are a piping contractor, plant operator, hoặc kỹ thuật viên bảo trì, understanding these requirements is essential for achieving a secure, không bị rò rỉ, and durable flange connection.

As a trusted flange manufacturer and supplier, sasa thuôn dài offers high-quality large diameter flanges with full compliance to ASME, EN, and custom specifications, as well as technical support for field assembly and installation.

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What Are Large Diameter Flanges?

Mặt bích đường kính lớn typically refer to flanges with nominal diameters of 24 inch trở lên, extending up to 2000 mm (hoặc 80 inch) or more. These flanges are found in:

• Large pipelines for water, dầu, khí đốt, or chemicals

• Pressure vessels and heat exchangers

• Storage tanks and silos

• Offshore and subsea installations

• Cooling towers and desalination systems

They are usually manufactured as cổ hàn, mù, khớp nối, or custom flanges bằng thép cacbon, thép không gỉ, or alloy steel, depending on the operating conditions.

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Principle Requirements for Large Diameter Flange Assembly

Proper assembly of large flanges is vital to ensure tính toàn vẹn cấu trúc, ngăn chặn áp lực, và độ tin cậy lâu dài. Below are the key principles to follow:

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1. Preparation of Components

Before starting the flange assembly process, all parts must be thoroughly inspected and prepared.

Làm sạch bề mặt

• Clean the gasket seating faces, lỗ bu lông, and flange surfaces using solvents or degreasing agents

• Remove bụi, dầu, rỉ sét, and old gasket residues

Kiểm tra trực quan

• Check flanges for độ phẳng, bề mặt hoàn thiện, Và machining defects

• Inspect for vết nứt, burrs, vết lõm, or out-of-round conditions

Bolt and Gasket Verification

• Confirm that bu lông, quả hạch, và vòng đệm meet the torque and material requirements

• Use the correct gasket type and size (vết thương xoắn ốc, RTJ, soft gasket, vân vân.)

sasa thuôn dài provides large flanges with machined faces, bevels, and standard markings for easy identification and pre-assembly checks.

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2. Proper Alignment

Misalignment can cause bolt bending, gasket failure, flange deformation, or even leakage. Accurate alignment is critical.

Use of Lifting Equipment

• Large flanges require cranes, slings, spreader bars, or hydraulic manipulators for safe handling

• Never force flanges into place using bolts

Pipe Support

• Sử dụng temporary pipe supports or jacks to maintain correct elevation and axial alignment

• Avoid sagging or torsional stress on the flange joint

Radial and Angular Tolerances

• Đảm bảo radial runout and face parallelism fall within acceptable limits as per ASME B31.3 hoặc VN 1591-1

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3. Lắp đặt miếng đệm

The gasket is a key sealing component and must be installed carefully:

• Check gasket for damage or warping

• Đảm bảo centered placement between flanges without protrusion

• Do not reuse gaskets or apply lubricants unless specified

• Keep gasket dry and clean during handling

Large diameter gaskets often require multiple installers or vacuum lifting tools for proper positioning.

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4. Bolt Tightening Sequence and Torque Control

Due to the number of bolts and the size of the flange, even distribution of load is crucial to prevent leakage and maintain sealing.

Cross-Bolting Pattern

• Use the star or criss-cross pattern to ensure uniform gasket compression

• Divide bolts into quadrants and tighten in stages

Nhiều đường chuyền

• First pass: 30% mô-men xoắn cuối cùng

• Second pass: 70%

• Final pass: 100% of specified torque

• Optional final rotational pass to ensure bolt tension equalization

Torque Tools

• Sử dụng calibrated torque wrenches, hydraulic bolt tensioners, or pneumatic tools

• Record all torque values during assembly

sasa thuôn dài recommends following ASME PCC-1 guidelines for bolting large diameter flanges to ensure consistent preload and joint integrity.

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5. Flange Face Protection and Handling

Large flanges are heavy and vulnerable to damage during transit and handling.

Protective Measures:

• Sử dụng face protectors during storage and shipping

• Avoid stacking flanges directly on flange faces

• Always lift using designated lifting points or holes

Improper handling may damage sealing surfaces, requiring costly rework or flange replacement.

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6. Thermal and Pressure Considerations

In applications involving temperature fluctuation or pressure cycles, consider the effect on bolt relaxation and gasket stress.

• Sự giãn nở nhiệt may loosen bolts—retighten after initial operation

• Pressure surge can strain the joint—select gaskets with proper recovery and compressibility

• Differential expansion of flange and pipe materials (ví dụ., stainless steel vs carbon steel) must be evaluated

sasa thuôn dài engineers provide technical support for flange selection and installation under thermal and mechanical loading conditions.

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7. Hydrostatic and Pneumatic Testing

Once assembled, the flange connection must be tested for leaks and integrity.

Kiểm tra thủy tĩnh:

• Fill the system with water

• Apply pressure 1.5x the design pressure

• Hold and inspect for pressure drop or visual leaks

Pneumatic Testing:

• Use air or nitrogen at low pressure

• Use bubble solution or leak detection spray

• Exercise extreme caution due to risk of explosive energy release

Document all test results, including pressure levels, khoảng thời gian, and observations.

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8. Documentation and Inspection

Thorough documentation ensures traceability and compliance.

• Torque logs, flange alignment records, and gasket type must be recorded

• Perform visual and dimensional inspections using feeler gauges, calipers, and dial indicators

• Verify material certifications (EN 10204 3.1/3.2) and conformity to drawing requirements

sasa thuôn dài provides MTCs, báo cáo chiều, and customized marking on all large flanges to simplify documentation.

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Safety Considerations During Assembly

• Always wear PPE: găng tay, giày bảo hộ, hard hats, eye protection

• Sử dụng lockout/tagout procedures when working on pressurized lines

• Secure tools, especially when working at height or with suspended flanges

• Never stand under a lifted flange or pipe

• Train personnel in safe rigging, lifting, and torqueing procedures

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Why Choose sasaflange for Large Diameter Flanges?

sasa thuôn dài offers a complete range of large diameter flanges from DN600 to DN2000 and beyond, with key advantages:

• Rèn chính xác và gia công CNC

• Custom manufacturing per drawing and non-standard specs

• Wide material options: thép cacbon, thép không gỉ, hai mặt, hợp kim niken

• Quality assurance: UT, RT, MT, PMI, thử nghiệm thủy tĩnh

• Fast lead times and global delivery

• Technical guidance for safe assembly and maintenance

Our large flanges are used in critical energy and infrastructure projects across the globe, supporting both EPC contractors and end users.

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Phần kết luận

các assembly of large diameter flanges is a complex task that demands careful planning, thực hiện chính xác, and strict adherence to standards. Từ component preparation and alignment to bolting sequences and leak testing, every step must be performed with accuracy to ensure a reliable, leak-free connection.

Whether you’re working on a water pipeline, refinery system, or industrial plant expansion, partnering with an experienced flange supplier like sasa thuôn dài ensures that your large diameter flanges meet the highest standards of sự an toàn, độ bền, và hiệu suất.