U-Tube Shell & Tube Heat Exchanger | ASME SA179 Tubes & SA266 Gr.2 Tubesheet | U-Tube Bundle Design for High ΔT Service – ASME/TEMA Fabrication
Product Description
Yuhong Group: Complete Heat Exchanger Solutions – From Components to Full Equipment
Yuhong Group Co., Ltd. designs and manufactures a comprehensive range of thermal equipment for global industries. Our core offerings include shell and tube heat exchangers, pressure vessels, air coolers, and a complete supply of critical components: finned tube bundles, U-tube bundles, heat exchanger tubesheets, and all related parts – ensuring full support for new projects and maintenance.
Product Focus: U-Tube Shell & Tube Heat Exchanger – Engineered for High Thermal Differential
Based on the attached photographs, this is a U-tube shell & tube heat exchanger – one of the most versatile and reliable designs for applications involving large temperature differences between shell-side and tube-side fluids.
The photographs show the following key features:
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Tube material: ASME SA179 (seamless carbon steel tubes) – providing excellent thermal conductivity and formability for U-bending
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Tubesheet material: ASME SA266 Gr.2 (forged carbon steel) – offering high strength and dimensional stability
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Flange material: ASME SA105 (forged carbon steel) – ensuring reliable bolted connections
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Design type: U-tube (single tubesheet, tubes can expand freely)
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Construction: Full ASME/TEMA compliance with hydrostatic testing and NDE
Key Components & Their Functions in This U-Tube Heat Exchanger
| Component |
Material (from photos) |
Role in Equipment Performance |
| U-Tube Bundle |
ASME SA179 (carbon steel) |
Carries tube-side fluid; U-bend allows free thermal expansion without stressing tubesheet. Eliminates need for expansion joint. |
| Heat Exchanger Tubesheet |
ASME SA266 Gr.2 (forged) |
Anchors U-tubes at the inlet end; separates shell side from tube side. Forged carbon steel provides excellent strength and toughness. |
| Shell |
Carbon steel (SA516 Gr.70 typical) |
Contains shell-side fluid; designed for pressure containment. |
| Channel / Bonnet |
Carbon steel (with SA105 flanges) |
Distributes fluid to the U-tube bundle; flanged connection allows access for bundle inspection and cleaning. |
| Baffles |
Carbon steel (SA516 Gr.70 typical) |
Support U-tubes; direct shell-side flow for optimal heat transfer. |
| Flanges |
ASME SA105 (forged) |
Provide leak-tight connections between channel, shell, and piping. Forged construction ensures reliable sealing. |
| Finned Tube Bundle (optional) |
Tube + aluminum/SS fins |
Not present in this unit – but we offer finned tube bundles as upgrades for air-cooling or gas-cooling applications. |
Why U-Tube Design? – Key Advantages Over Fixed Tubesheet
| Feature |
U-Tube Heat Exchanger |
Fixed Tubesheet Heat Exchanger |
| Thermal expansion |
Handled naturally by U-bend – no expansion joint |
Requires expansion joint or floating head |
| Tubesheet count |
Single tubesheet – simpler and more economical |
Two tubesheets – more complex |
| Tube replacement |
Individual tubes can be replaced (straight sections) |
Tube replacement possible but more limited |
| Heat transfer area |
Slightly reduced in U-bend region |
Full straight length area |
| Mechanical cleaning (tube inside) |
Tube cleaning accessible from one end only |
Tubes accessible from both ends |
| Cost |
Lower than floating head; higher than fixed tubesheet |
Most economical for low ΔT |
When to Specify a U-Tube Heat Exchanger:
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Thermal differential > 50°C – U-bend handles expansion without expansion joint
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High tube-side pressure – single tubesheet design handles pressure efficiently
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Shell-side cleaning is sufficient – cleaning of U-bend internal surfaces is limited
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Need for cost-effective thermal expansion solution – U-tube is more economical than floating head
Technical Highlights of Our U-Tube Heat Exchanger
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ASME SA179 seamless tubes: Cold-drawn, low-carbon steel provides excellent thermal conductivity, formability for U-bending, and consistent wall thickness for reliable tube-to-tubesheet joints.
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ASME SA266 Gr.2 forged tubesheet: Forged carbon steel offers superior mechanical properties compared to rolled plate – particularly in the through-thickness direction. This is critical for high-pressure tube-side service and long-term tube joint integrity.
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ASME SA105 forged flanges: Forged carbon steel flanges provide reliable sealing and resistance to galling during bolt-up – essential for maintaining leak-tight joints over multiple maintenance cycles.
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Precision U-bending: Our U-tubes are bent with controlled radius to avoid wall thinning or ovality – ensuring consistent tube life and predictable thermal expansion behavior.
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Tube-to-tubesheet joint: Precision rolling (and optional seal welding) creates leak-tight joints that withstand thermal cycling and pressure fluctuations.
Knowledge Module: U-Tube vs. Floating Head vs. Fixed Tubesheet – Which to Choose?
| Operating Condition |
Recommended Design |
Rationale |
| ΔT < 50°C, clean service |
Fixed tubesheet |
Most economical, simple construction |
| ΔT > 50°C, moderate fouling |
U-tube |
Handles thermal expansion without expansion joint; lower cost than floating head |
| ΔT > 50°C, heavy fouling |
Floating head |
Bundle removable for mechanical cleaning; U-tube not suitable for heavy tube-side fouling |
| High tube-side pressure |
U-tube |
Single tubesheet design handles high pressure efficiently |
| Frequent thermal cycling |
U-tube or floating head |
U-bend or floating head accommodates expansion and contraction |
Typical Applications for U-Tube Heat Exchangers
| Industry |
Application |
Why U-Tube |
| Petrochemical / Refinery |
Crude preheaters, gas coolers, feed/effluent exchangers |
Handles large temperature differentials in process service |
| Power generation |
Lube oil coolers, generator coolers, feedwater heaters |
Reliable thermal expansion management |
| Chemical processing |
Reactor temperature control, solvent heating/cooling |
Adaptable to varying process conditions |
| HVAC / district heating |
Steam converters, hot water generators |
Cost-effective thermal expansion solution |
| Compressor stations |
Intercoolers, aftercoolers |
High-pressure capability; U-bend design handles cyclic service |
Component-Only Supply – We Also Provide for Maintenance & Spares
If your existing U-tube heat exchanger needs replacement parts, we supply individual components without ordering a complete new exchanger:
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U-tube bundles – direct replacement for existing shells – built to your drawing
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Finned tube bundles – for air cooler retrofits and gas-cooling applications
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Heat exchanger tubes – ASME SA179, stainless steel, alloy – cut to length, bent, and end-prepared
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Heat exchanger tubesheet – SA266 Gr.2, forged, drilled and grooved per your pattern
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Flanges – SA105, SA350 LF2, stainless – any facing type
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Baffles, tie rods, spacers – machined to your dimensions
How to Specify a Replacement U-Tube Bundle Correctly
To avoid mismatches, we need the following information (send any of these):
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Original bundle drawing – best option. We duplicate tube count, U-bend radius, tube length, and baffle spacing exactly.
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Old bundle (physical sample) – we can measure and reverse-engineer a perfect match.
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Shell internal dimensions – shell ID, tubesheet groove dimensions, bolt circle.
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Service conditions – temperature, pressure, fluids – to confirm material selection is appropriate.
Typical Materials for U-Tube Heat Exchangers
| Component |
Carbon Steel Option |
Stainless Steel Option |
Alloy Option |
| Tubes |
SA179 |
SA213 TP304/316L |
Monel, Inconel, titanium |
| Tubesheet |
SA266 Gr.2 |
SA182 F304/316L |
Alloy forgings |
| Flanges |
SA105 |
SA182 F304/316L |
Alloy forgings |
| Shell |
SA516 Gr.70 |
SA240 304/316L |
Alloy plate |
Quality Assurance & Documentation
Every U-tube shell & tube heat exchanger we fabricate includes:
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ASME Code compliance – per ASME Section VIII, Division 1
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TEMA standards – design, fabrication, and inspection per TEMA requirements
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Material Test Certificates (MTC) per EN 10204 3.1 – full traceability
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NDE reports – RT, UT, MT, PT as required
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Hydrostatic test report – shell side and tube side
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PMI (Positive Material Identification) – available on request
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Third-party inspection (SGS, BV, TÜV) – at buyer’s request
Get a Quotation for Your U-Tube Heat Exchanger
To quote a U-tube shell & tube heat exchanger like the one in your photographs, send the following to jimmy@steelseamlesspipe.com:
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Process data sheet (flow rates, inlet/outlet temperatures, pressures)
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Fluid composition (corrosivity, fouling tendency)
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Tube material preference (SA179 carbon steel as shown – or stainless steel, alloy)
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Required code compliance (ASME, TEMA)
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Drawing (PDF, scan, or hand sketch) if available
Our engineers will respond with a technical proposal, general arrangement drawing, and competitive price – typically within 48 hours.
