Shell and Tube Heat Exchanger Tube Bundle with Fixed U-Tube Floating Head Design

The tube bundle is the removable or fixed core assembly within a shell and tube heat exchanger, comprising tubes, tube sheets, baffles, tie rods, and spacers. This assembly is the primary heat transfer interface between two fluid streams - one flowing inside the tubes (tube side) and the other across the external tube surfaces (shell side).

The tube bundle is designed and manufactured per TEMA Class C (commercial), B (chemical), or R (refinery), ASME Section VIII Division 1 or Division 2, and GB/T 151 for domestic applications. This product is supplied as a replacement bundle, a spare bundle, or as part of a new heat exchanger assembly.

• Tubes are expanded or welded into tube sheets at both ends
• Shell and tube sheets are integrally welded or bolted to the shell
• Thermal expansion is accommodated by an expansion joint installed on the shell when ΔT between tube and shell exceeds the allowable for the material combination
• Applicable for: Clean shell-side fluids, temperature differential ≤ 60°C (carbon steel) / ≤ 40°C (stainless steel) without expansion joint; non-fouling services

• Tubes are bent into a U-shape, with both ends fixed to a single tube sheet
• Each tube is free to expand independently, accommodating large temperature differentials without requiring a shell expansion joint
• Applicable for: High thermal differential (ΔT up to 200°C), high-pressure gas service, hydrogen service, thermal shock conditions
• Limitation: Individual tube cleaning is not possible - only chemical cleaning; U-bend radius ≥ 2* tube OD per TEMA RCB-4.52

• One tube sheet is fixed (stationary) and the other is floating, allowing the bundle to expand independently from the shell
• Rear head is removable, enabling bundle extraction for mechanical cleaning
• Applicable for: Severe fouling services where mechanical cleaning is required, large ΔT, high shell-side fouling factor (> 0.0005 m²*K/W per TEMA table)
• Limitation: Higher cost, more flange joints, greater tube sheet thickness requirement

• Carbon steel SA-516 Gr.70 - for non-corrosive tube-side fluids
• Stainless clad (304L/316L over CS) - for corrosive tube-side fluids with high pressure (cladding thickness min. 3mm per ASME VIII-1 UW-13)
• Solid stainless 304L / 316L - for fully corrosive service
• Duplex / Titanium - for offshore and seawater service
• Alloy overlay (Inconel 625 weld overlay, min. 3mm) - for severe sour or chloride service

When ordering a replacement bundle, provide:

1. Original bundle drawing number (if available)
2. TEMA type (L / M / N / U / P / S / T / W)
3. Shell ID, tube OD and wall thickness, tube length, tube pitch, tube arrangement
4. Tube sheet thickness and material
5. Baffle type, baffle spacing, number of baffles
6. Tube-to-tubesheet joint type (expanded / welded / combined)
7. Design pressure and temperature (tube and shell sides)
8. Fluid composition (tube and shell sides) - to verify material compatibility
9. Nozzle orientation (if applicable) - for inlet/outlet alignment with existing piping
10. Required corrosion allowance (tube and tube sheet) - for remaining life extension

1. Define TEMA type based on thermal expansion and cleaning requirements:
   • Fixed tubesheet (L/M/N) - for clean shell side, ΔT ≤ 60°C
   • U-tube (U) - for large ΔT, hydrogen service, high pressure
   • Floating head (P/S/T/W) - for severe fouling, mechanical cleaning
2. Select tube material based on tube-side fluid corrosivity and temperature.
3. Select tube sheet material based on shell-side and tube-side fluid compatibility (clad or solid).
4. Select tube OD, wall thickness, pitch, and arrangement:
   • Triangular pitch for max surface area
   • Square pitch for mechanical cleaning access (rod/brush)
5. Specify baffle type and spacing - based on shell-side allowable ΔP and vibration criteria.
6. Specify joint type - expanded (low cost), welded (gas/hydrogen), or combined (cyclic service).
7. Provide design pressure and temperature for hydrotest and material grade selection.
8. Specify whether a spare bundle is required for service rotation (reduce downtime during cleaning).