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.
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:
| Component | Standard Material Grades | Applicable Specification |
|---|---|---|
| Tubes (smooth / low-finned) | SA-179, SA-213 TP304L/316L, SA-789 UNS S31803, SB-338 Gr.2, SB-163 UNS N06600 | ASTM/ASME tube specification |
| Tubesheet (fixed / floating) | SA-266 Gr.2, SA-182 F304L/F316L, Clad plate (≥3 mm overlay) | ASME SA-266 / SA-182 / clad per ASME VIII-1 UW-13 |
| Baffles & Support Plates | SA-516 Gr.70, SA-387 Gr.11/22 (Cr-Mo for high T) | ASME SA-516 / SA-387 |
| Tie Rods & Spacers | SA-193 Gr.B7 / SA-194 Gr.2H, or alloy equivalent | ASME SA-193 / SA-194 |
| Impingement Plate | Same or compatible with tube material | Per exchanger nozzle location |
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:
| Test / Inspection | Method | Basis / Acceptance |
|---|---|---|
| Tube-to-tubesheet joint | Expanded + seal welded or strength welded | Per ASME VIII-1 App. A; leak test at 1.5× design pressure |
| Tube-side hydrotest | Hydraulic pressure applied to tube pass(es) | Hold per ASME UG-99; no pressure drop |
| Shell-side hydrotest (with test ring for removable bundles) | Hydraulic pressure to shell side | No visible leakage at joint; test ring bolted per API 660 |
| Dimensional check | Measured against approved fabrication drawing | Tube pitch, baffle spacing, orientation, pass partition location |
| NDE - tubes (full length) | Eddy current (ET) or internal rotary UT (IRUT) | Per ASME Section V; acceptance per purchaser spec |
| NDE - tubesheet forging | UT for lamination | Per SA-388 / SA-435 |
| Post-weld heat treatment (PWHT) | Furnace or local, as required by thickness/material | Per ASME VIII-1 UCS-56 / UHT-56 |
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.
| Industry Sector | Process Unit | Tube Bundle Service Conditions |
|---|---|---|
| Petroleum Refining | Crude preheat trains, hydrotreaters, catalytic reformers | 200-450°C; hydrogen/hydrocarbon; up to 20 MPa |
| Petrochemical | Ethylene cracker quench coolers, recycle gas coolers | High-temp hydrocarbon; cyclic operation |
| Chemical Processing | Reactor effluent coolers, distillation reboilers, condensers | Corrosive or fouling fluids; varying pressure |
| Oil & Gas | Gas dehydration, amine regenerators, lean/rich heat exchangers | Wet sour gas; CO₂/H₂S service |
| Power & Industrial | Feedwater heaters, lubrication oil coolers, intercoolers | Clean or moderate-fouling water/oil service |
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.
