API 660 Compliant ASME Section VIII Div. 1 Tube Bundle for Removable Installatio

Yuhong Group Co., Ltd. manufactures shell & tube heat exchanger tube bundles in accordance with API 660 and TEMA Class R requirements. Our facility is qualified for ASME Section VIII Div. 1 pressure vessel construction, with NDE and heat treatment capabilities covering carbon steel, alloy steel, stainless steel, duplex, and nickel-base materials.

This tube bundle is the core heat transfer component of a shell & tube heat exchanger, designed for removable or fixed installation within a cylindrical shell. The bundle consists of a tubesheet at one or both ends, a predetermined number of tubes arranged in a specified layout pattern (triangular, square, or rotated square), baffle plates to direct shell-side flow and support the tubes, tie rods with spacers to secure the baffle stack, and optional impingement plate at the inlet nozzle.

• Fixed tubesheet - tubesheet welded or bolted to the shell; no differential thermal expansion accommodation; suitable for moderate temperature differences
• Heat Exchanger tube - each tube, allowing free thermal expansion; fitted with floating head, no expansion joint; removable bundle
• Floating head - one tubesheet fixed, the other free to move axially; accommodates large thermal differentials and permits full tube cleaning

Each bundle is engineered per the purchaser's process data sheet, with tube count, pass arrangement, baffle spacing, and material selection calculated to meet specified heat duty, pressure drop, and allowable tube vibration margin.

All materials are specified per ASME Section II and conform to API 660 supplementary requirements. Typical selections are listed below:

Tube pitch, baffle thickness, and unsupported tube span are calculated per TEMA and API 660 vibration avoidance guidelines, with baffle spacing limited to maintain tube natural frequency above excitation frequencies.

Each tube bundle is subject to the following inspection and test sequence. Additional NDE (RT, MT, PT, UT) is available per purchaser specification:

Fixed tubesheet bundles additionally require shell-side hydrotest with the shell assembled. For U-tube and floating head bundles, the test ring method is employed to verify joint integrity before installation.

The API 660 tube bundle is specified for critical services where reliability, maintainability, and code compliance are mandatory.

Every material component is mill-tested and traceable to ASME Section II. Welding procedures are qualified per ASME Section IX, with welders certified for each material group.

Tube layout, baffle cut orientation, and pass arrangement are optimized using thermal-hydraulic calculations (e.g., HTRI) to match the required duty within allowable pressure drop limits. For fouling services, wider tube pitch and removable bundles are recommended.

Tube holes are drilled and/or reamed to within tolerance per TEMA standards. Tube ends are expanded and optionally seal-welded to the tubesheet, with expansion depth and torque controlled to prevent tube thinning and ensure consistent joint strength.

• Low-finned tubes for increased surface area in gas-phase or viscous-fluid duty
• Bimetallic tubes for corrosion resistance with cost-effective base material
• NACE-compliant materials and PWHT for wet sour service
• Critical service NDE (100% RT of tube-to-tubesheet welds, helium leak testing)
• Replacement bundles dimensioned to match existing shells with no shell modification