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{"title":"Heat Exchanger (ASME \/ TEMA \/ABS) High-Efficiency, Test-Certified Heat Transfer","imgUrl":"https:\/\/img.chinax.com\/nimg\/61\/72\/e139e3396f4cf6c32ab7c45cf092-200x200-1\/heat_exchanger_28asme_2f_tema_2fabs_29_high_efficiency_2c_test_certified_heat_transfer_for_industrial_26_marine_applications.jpg","attrs":{"Brand Name":"YUHONG","Model Number":"SHELL AND TUBE HEAT EXCHANGER","Certification":"ASME \/ TEMA \/ABS","Place of Origin":"CHINA"}}
{"title":"Carbon Steel Shell & Tube Heat Exchanger with Fixed Tubesheet Floating Head and","imgUrl":"https:\/\/img.chinax.com\/nimg\/72\/09\/fed86c184df0c30c4ef93e397c89-200x200-1\/carbon_steel_shell_26_tube_heat_exchanger_with_fixed_tubesheet_floating_head_and_u_tube_designs_for_refinery_power_hvac.jpg","attrs":{"Brand Name":"YUHONG","Model Number":"ASME SA179","Certification":"ASME, ABS, DNV-GL , BV, LR , KR, CCS, PED, TUV, ISO9001, AD2000","Place of Origin":"CHINA"}}
{"title":"SA213 T2 Crude Oil Top P.A. Heat Exchanger for Crude Oil Distillation Unit with","imgUrl":"https:\/\/img.chinax.com\/nimg\/fb\/d9\/a0d5744a597130c9d4127715fe12-200x200-1\/sa213_t2_crude_oil_top_p_a_heat_exchanger_for_crude_oil_distillation_unit_with_lpg_unit.jpg","attrs":{"Brand Name":"YUHONG","Model Number":"SHELL AND TUBE HEAT EXCHANGER","Certification":"ASME VIII Div. 1, PED\/97\/23\/CE, TEMA R, TEMA C, TEMA B","Place of Origin":"CHINA"}}
Materials: CS/304/316L/Ti | Design Temp -40°C to +500°C | Applications: High ΔT Services / Vaporizing / Gas Heating | Manufactured per TEMA or ASME VIII-1
Technical Advantage Overview
The hairpin heat exchanger (also known as a double-pipe or multitube hairpin) is engineered for services where thermal expansion differential between the tube and shell fluids exceeds the practical limit of a fixed tube sheet design. Unlike conventional straight-shell exchangers, the hairpin construction incorporates a U-shaped tube bundle enclosed within a return-bend shell, creating a true countercurrent flow path in a single pass.
Key Differentiator - True Countercurrent Flow in Compact Footprint
In a hairpin heat exchanger, the shell-side fluid and tube-side fluid flow in opposite directions for the entire length of the exchanger. This yields a log mean temperature difference (LMTD) correction factor F = 1.0 for all services, unlike shell-and-tube exchangers with multiple passes where F drops below 1.0. The result is either:
Reduced surface area requirement for the same duty (typically 15-25% less than a 1-2 shell-and-tube configuration), or
Achievable approach temperatures as low as 3°C to 5°C without requiring a larger unit.
Parameter-Based Construction Features
Tube Bundle Configuration
Single pass only - each tube makes one U-turn inside the return bend housing
Tube diameters: Common range Ø12mm to Ø38mm (3/8" to 1.5" OD)
Tube length (straight section): 2.0m to 12.0m per leg
Number of tubes per bundle: Single tube (double pipe) or multitube (from 4 to 200+ tubes)
Shell Construction (Hairpin Body)
Shell nominal diameter: DN80 to DN600 (3" to 24")
Return bend housing: Removable bolted cover or welded cap with inspection opening
Shell-side flow: Single pass, true countercurrent
Baffle type (if multitube): Segmental baffles or full support plates with baffle spacing determined by unsupported tube length per TEMA RCB-4.2 (max unsupported length ≤ 36× tube OD for carbon steel, ≤ 30× tube OD for stainless steel)
Thermal Expansion Management - No Expansion Joint Required
The hairpin design inherently accommodates differential thermal expansion without requiring an expansion joint or a floating head. The U-bundle is fixed at the front tubesheet (statically bolted to the shell flange) and free at the return end within the housing. Allowable temperature differential ΔT between tube and shell sides is limited only by material stress allowables, not by a mechanical expansion device. For carbon steel tubes with stainless steel shell (or vice versa), differential design up to 150°C is achievable without exceeding ASME VIII-1 thermal stress limits.
Key Operating Parameters: Tube side 400°C to 500°C, shell side 200°C to 350°C, ΔT up to 200°C
Construction Selection: Multitube hairpin, no baffles (full support plates only) to avoid vibration in low-density gas
Design Note: For gas-side pressure drop < 5 kPa, specify low-fin tubes (19 fpi, fin height 1.5mm) to increase surface area without adding tube rows.
Service 2: Liquid Vaporization (Thermosiphon or Kettle-Type Equivalent)
Typical Media (Tube/Shell): Process fluid boiling / Steam or hot oil on shell side
Tube Material: Carbon steel or 316L (depending on fluid corrosivity)
Shell Material: Carbon steel
Key Operating Parameters: Shell side steam at 0.3 to 1.0 MPa (133°C to 184°C), tube side boiling at 80°C to 150°C
Construction Selection: Single-tube hairpin (double pipe) for vaporization of clean fluids; multitube hairpin with vertical orientation for larger duties
Design Note: Vertical orientation (tubes vertical, return bend at top or bottom) provides natural circulation thermosiphon effect. Minimum submergence height = 1.5× heated tube length to avoid dry-out.
Service 3: High-Pressure Hydraulic Oil Cooling (Offshore / Industrial Hydraulics)
Typical Media (Tube/Shell): High-pressure oil (up to 20 MPa) / Seawater or cooling water
Tube Material: Seamless 316L (corrosion resistant, no weld seam in pressure boundary)
Shell Material: 316L or titanium (for seawater shell side)
Key Operating Parameters: Tube side oil at 15 MPa to 20 MPa, 40°C to 80°C; shell side water at 5°C to 30°C
Design Note: For oil cooler duties with < 5 m² surface area, single-tube hairpin provides simpler pressure boundary certification compared to multitube bundles.
Service 4: Cryogenic Fluid Vaporization (LNG / Liquid Nitrogen)
Typical Media (Tube/Shell): Cryogenic liquid (-196°C to -40°C) warming to gas / Ambient air or warm water
Tube Material: 304 or 316L (retains impact toughness down to -196°C per ASTM E23 - Charpy V-notch ≥ 27J average)
Shell Material: 304 (no carbon steel at cryogenic temperatures due to embrittlement)
Key Operating Parameters: Tube side inlet -196°C to -40°C, outlet +5°C to +30°C; shell side ambient air or water at +20°C
Construction Selection: Multitube hairpin with extended shell-side fins (aluminum or copper) for air-heated vaporizers; bare tube for water-heated designs
Design Note: For air-heated ambient vaporizers, minimum fin density 4 fins per inch, fin height 12mm to 16mm to maintain heat transfer rate above 30 W/m²*K under frost conditions.
Manufacturing & Quality Controls
Tube-to-Tubesheet Joint Integrity
Welded-only for high-pressure or toxic service: Full penetration GTAW, 100% radiography (RT) per ASME VIII-1 UW-51
Expanded-only for non-hazardous service: Hydraulic expansion at 180 to 220 MPa, pull-out test to ≥ 25 MPa on first-article bundle
Weld + expand for cyclic or thermal shock service: Seal weld (1.5mm fillet) + hydraulic expansion at 160-200 MPa
Return Bend Housing Inspection
Dye penetrant (PT) on all internal fillet welds of return bend cover (if welded cap design)
Borescope inspection of internal tube support alignment - tube pass-through verification (no blocked tubes)
Hydrostatic Testing (per bundle, before shell closure)
Tube side: 1.3 × design pressure, hold 30 minutes, zero drop
Shell side (after final assembly): 1.3 × design pressure, hold 30 minutes, zero drop
Selection Quick Reference
If your process requires... → Specify hairpin instead of standard shell-and-tube when:
Temperature difference between tube and shell side > 80°C (avoid expansion joint)
Approach temperature required < 10°C (true countercurrent provides LMTD F=1.0)
Vaporizing or condensing in a single pass without flow maldistribution
Space is constrained - hairpin footprint is typically 40-50% of equivalent straight-shell length
Future capacity increase possible - hairpin exchangers can be installed in series (multiple hairpins with interconnected piping)
Limitation Statement
The hairpin design is not optimal for the following services:
Very high shell-side flow rates (> 500 kg/s) - pressure drop becomes excessive due to single shell-side pass
Severe fouling shell-side fluids without chemical cleaning access - return bend housing may restrict mechanical cleaning compared to a pull-through floating head bundle
Note: All performance statements above (e.g., F=1.0, ΔT differential up to 200°C, approach temperature 3-5°C, surface area reduction 15-25%) are derived from TEMA 10th edition design equations and ASME VIII-1 thermal stress calculations. No field performance percentage improvements are claimed without test data.
For a specific duty datasheet and preliminary sizing, provide: tube-side fluid, shell-side fluid, hot side inlet/outlet temperatures, cold side inlet/outlet temperatures, allowable pressure drops (tube and shell), and operating pressures.
Technical Comparison: Hairpin vs Conventional Shell-and-Tube
Parameter
Hairpin Heat Exchanger
Conventional Straight Shell-and-Tube (1-2 Pass or U-Tube)
Parameter-Based Justification
Flow arrangement
True countercurrent (single pass both sides)
Mixed / cross-countercurrent (F factor < 1.0 for 1-2 or 2-4 pass)
Hairpin LMTD correction factor F = 1.0 per TEMA. For 1-2 shell-and-tube, F ≥ 0.8 required; below 0.8 requires multiple shells in series.
Thermal approach (hot outlet vs cold inlet)
Achievable approach ΔT = 3°C to 5°C
Achievable approach ΔT = 10°C to 15°C (single unit)
Hairpin F=1.0 allows approach limited only by NTU. For shell-and-tube with F=0.85, required NTU increases by 18% for same approach.
Differential thermal expansion (tube vs shell)
Accommodated inherently by U-bundle free end
Fixed tube sheet requires expansion joint when ΔT > 60°C (CS/CS) or > 40°C (CS/SS)
Per TEMA RCB-4.3: fixed tubesheet without expansion joint limited to differential expansion stress ≤ 55 MPa. Hairpin has no such limit below material creep range.
Maximum ΔT (tube side to shell side inlet)
Up to 200°C (within ASME VIII-1 stress allowables)
≤ 60°C (carbon steel fixed tubesheet without expansion joint)
Based on thermal stress calculation per ASME VIII-1 UG-23(c): for CS with E=200 GPa, α=12×10⁻⁶ /°C, ΔT=200°C yields σ=α×E×ΔT/2 = 240 MPa - exceeds 138 MPa allowable. Hairpin avoids this by free-end U-bundle.
Single-unit surface area range
1 m² to 500 m² (multitube)
5 m² to 2,500 m²
Hairpin limited by bundle pull-through weight (max bundle mass ~10,000 kg for vertical pull). Straight-shell limited by shell diameter (typically ≤ 2.5m ID) and transport limits.
Shell-side pressure drop (single pass)
ΔP = f × (L/D_h) × (ρv²/2) with L = total hairpin developed length (2× straight leg + return bend)
ΔP per TEMA for E-shell (single pass shell)
For identical duty and shell-side mass velocity, hairpin pressure drop is approximately 40-60% higher than straight E-shell due to return bend losses (experimental correlation from HTRI).
Mechanical cleaning access (shell side)
Limited - return bend housing restricts access
Full access for floating head or pull-through bundle (U-tube)
Hairpin shell side cannot accommodate a pull-through bundle. Fixed bundle requires chemical cleaning. Shell-side fouling factor > 0.0005 m²*K/W is not recommended for hairpin without chemical cleaning capability.
Tube-side cleaning (mechanical)
Full access - U-bend radius ≥ 2× OD allows standard tube wiper
U-tube: accessible (same bend radius rule). Fixed tubesheet: full access.
Per TEMA RCB-4.52: minimum U-bend radius = 2× tube OD for mechanical cleaning. Both designs comply.
Footprint (installed length for equivalent duty)
Straight leg length L (2L total developed length but stacked or side-by-side)
Straight length L_shell (usually 1.2× to 1.5× hairpin leg length for same surface area)
Hairpin multitube typically requires 40-50% less linear space because surface area is distributed over two legs in parallel. Actual layout dependent on headroom and tube count.
Typical maximum design pressure (tube side)
Up to 35 MPa (single tube hairpin / double pipe)
Up to 20 MPa (multitube bundle with welded tubesheet)
Per ASME VIII-1 and VIII-2: seamless tube in double-pipe hairpin eliminates tubesheet ligament stress concentration. Multitube bundle limited by tubesheet hole deformation (ASME VIII-1 UG-34).
Standard manufacturing code
TEMA C / B / R + ASME VIII-1 or VIII-2
TEMA C / B / R + ASME VIII-1
Both designs follow same TEMA and ASME sections. Hairpin return bend cover requires additional UW-13 weld detail.
Company Details
Bronze Gleitlager
,
Bronze Sleeve Bushings
and
Graphite Plugged Bushings
from Quality China Factory
Business Type:
Manufacturer,Exporter,Trading Company,Seller
Year Established:
1990
Total Annual:
50M-75M
Employee Number:
50~850
Ecer Certification：
Verified Supplier
Yuhong Holding Group equipments production base at Jiangsu Jiangyin City, Jinjiang City and Yancheng City. Total production area around 184000 square meters, main products : Heat Exchanger, Condenser, Pressure Vessel , Fired Heater, Economizer, Columns, Reactor.
... Yuhong Holding Group equipments production base at Jiangsu Jiangyin City, Jinjiang City and Yancheng City. Total production area around 184000 square meters, main products : Heat Exchanger, Condenser, Pressure Vessel , Fired Heater, Economizer, Columns, Reactor.
...
