Double Coil Barrel Heat Exchanger — Stainless Steel Coil Tube (Coiltube) Technical Specification
1. Product Overview
The Double Coil Barrel Heat Exchanger (双盘管桶式换热器) represents a highly efficient thermal exchange apparatus engineered around two concentric stainless steel coil tubes (盘管/Coiltube) housed within a cylindrical pressure vessel. This design maximizes the heat transfer surface area within a compact footprint, making it ideal for industrial fluid-to-fluid and fluid-to-gas thermal management applications. The coil tube geometry facilitates turbulent flow conditions even at relatively low Reynolds numbers, thereby enhancing convective heat transfer coefficients and overall thermal performance.
Wenzhou Jixing Metal Materials Co., Ltd (温州继兴金属材料有限公司) supplies precision-manufactured stainless steel coil tubes specifically designed for integration into double coil barrel heat exchanger assemblies. The product catalog designation (Serial No. 862) corresponds to a standardized coil tube configuration optimized for multi-pass thermal cycling under demanding process conditions.
2. Material & Properties
The coil tubes are fabricated from austenitic stainless steel grades selected for superior corrosion resistance, mechanical integrity, and thermal stability. The primary material specifications are as follows:
- Grade 304 (UNS S30400 / 06Cr19Ni10): Chromium-Nickel austenitic stainless steel with excellent general corrosion resistance, weldability, and formability. Suitable for food-grade, pharmaceutical, and chemical processing environments.
- Grade 316 (UNS S31600 / 022Cr17Ni12Mo2): Molybdenum-enhanced austenitic stainless steel offering superior resistance to pitting and crevice corrosion in chloride-containing environments. Preferred for marine, desalination, and aggressive chemical service.
- Grade 316L (UNS S31603 / 022Cr17Ni12Mo2): Low-carbon variant of Grade 316 providing enhanced weldability and resistance to intergranular corrosion (IGC) in sensitization-prone service temperatures.
Key Mechanical Properties (Austenitic Stainless Steel Coil Tube)
| Property | Grade 304 | Grade 316 | Grade 316L |
|---|---|---|---|
| Tensile Strength (MPa) | ≥ 520 | ≥ 515 | ≥ 485 |
| Yield Strength (MPa) | ≥ 205 | ≥ 205 | ≥ 170 |
| Elongation (% min.) | ≥ 40 | ≥ 40 | ≥ 45 |
| Thermal Conductivity (W/m·K) @ 100°C | 16.3 | 14.6 | 14.6 |
| Operating Temperature Range (°C) | −196 to +870 | −196 to +870 | −196 to +870 |
| Corrosion Resistance (pH tolerance) | Neutral to mildly acidic | Chloride-resistant | Chloride-resistant (welded) |
3. Specifications
| Parameter | Specification |
|---|---|
| Product Designation | Coiltube — Double Coil Barrel Heat Exchanger (Serial No. 862) |
| Coil Tube Outer Diameter (OD) | Φ 12 mm – Φ 51 mm (customizable) |
| Coil Tube Wall Thickness | 0.5 mm – 3.0 mm |
| Coil Pitch (Spacing) | 15 mm – 60 mm |
| Coil Diameter (Helical) | Φ 150 mm – Φ 800 mm |
| Number of Turns | 8 – 40 (configurable per thermal duty) |
| Barrel (Shell) Diameter | Φ 400 mm – Φ 1200 mm |
| Barrel Length | 600 mm – 2400 mm |
| Design Pressure | Up to 2.5 MPa (adjustable) |
| Design Temperature | −40°C to +250°C (standard); up to +450°C (special order) |
| Surface Finish | 2B / No.4 Hairline / Electropolished (Ra ≤ 0.4 μm) |
| End Connection | Threaded (BSP/NPT), Flanged (ANSI/EN), or Welded (TIG/Orbital) |
| Heat Transfer Efficiency | U-value: 800 – 2,500 W/m²·K (depending on fluid pair and flow regime) |
| Standard Compliance | ASTM A213 / A269, GB/T 12771, EN 10216-5, ASME B31.3 |
4. Manufacturing Process
The production of precision stainless steel coil tubes for double coil barrel heat exchangers follows a rigorous, multi-stage manufacturing protocol:
- Material Selection & Inspection: Virgin stainless steel strip or seamless tubing is sourced from certified mills. Incoming material undergoes spectroscopic analysis (PMI — Positive Material Identification) to verify chemical composition compliance with ASTM/GB standards.
- Coiling Forming: Cold bending or hot forming processes are employed to create the helical coil geometry. CNC-controlled coiling machines ensure uniform pitch, consistent coil diameter, and minimal residual stress. For tight tolerance requirements, precision die-forming is utilized.
- Heat Treatment: Solution annealing at 1050–1150°C followed by rapid water quenching restores full austenitic microstructure, eliminates residual stresses, and maximizes corrosion resistance. Stress-relief annealing at 300–400°C may be applied post-forming to prevent cold-work hardening.
- Surface Treatment: Pickling and passivation remove mill scale and form a protective chromium oxide passive film. Electropolishing may be applied for ultra-low surface roughness applications in pharmaceutical or food processing sectors.
- Welding & Assembly: Coil tube ends are joined to the barrel shell using orbital TIG (Tungsten Inert Gas) welding or automatic orbital welding systems. Weld parameters are precisely controlled to prevent sensitization and maintain intergranular corrosion resistance. All welds undergo 100% visual inspection and spot radiographic testing (RT).
- Pressure & Leak Testing: Hydrostatic pressure testing at 1.5× design pressure for a minimum of 30 minutes verifies structural integrity. Helium leak detection (≤ 1×10⁻⁹ mbar·L/s) confirms hermetic sealing for vacuum-critical applications.
- Final Inspection & Certification: Dimensional verification via coordinate measuring machine (CMM), ultrasonic thickness measurement, and material traceability documentation complete the quality assurance cycle.
5. Applications
The Double Coil Barrel Heat Exchanger with stainless steel coil tubes finds extensive application across multiple industrial sectors:
- Chemical Processing: Reactant preheating/cooling, solvent recovery, and thermal management of corrosive process streams (acids, alkalis, halogenated compounds).
- Food & Beverage Industry: Pasteurization, sterilization, milk heating, juice pasteurization, and CIP (Clean-in-Place) compatible thermal processing. 304/316L grades meet FDA and EHEDG hygiene standards.
- Pharmaceutical Manufacturing: Sterile fluid heating, GMP-compliant process vessels, and heat exchangers for aseptic production lines.
- Petrochemical & Oil Refining: Crude oil fractionation, catalyst cooling, and heat recovery in distillation columns. 316/316L grades resist sour gas (H₂S) and chloride environments.
- Marine & Offshore: Seawater cooling loops, bilge water heating, and ballast water treatment systems where chloride-induced pitting is a primary concern.
- Power Generation: Boiler feedwater preheating, condensate recovery, and waste heat recovery systems in combined cycle power plants.
- HVAC & Refrigeration: Chilled water loop heat exchangers, condenser coils, and evaporator assemblies for industrial cooling systems.
- Biotechnology & Wastewater Treatment: Fermentation vessel heating, bioreactor temperature control, and effluent thermal conditioning.
6. Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management infrastructure ensuring product reliability and regulatory compliance:
- ISO 9001:2015 — Quality Management System certification covering the entire supply chain from raw material procurement to final delivery.
- ISO 14001:2015 — Environmental Management System demonstrating sustainable manufacturing practices.
- CE Marking — Conformity with European Pressure Equipment Directive (PED 2014/68/EU) for pressure-containing equipment.
- ASME Stamp (U/U1/U2) — National Board Registration for pressure vessel and heat exchanger components (where applicable).
- ASTM A213 / A269 — Seamless and welded stainless steel tubing specifications for heat exchangers and boiler tubes.
- GB/T 12771 — Chinese national standard for welded stainless steel tubes for general applications.
- EN 10216-5 — European standard for welded stainless steel tubes for heat exchangers.
- ASME B31.3 — Process piping design code compliance for thermal cycling and fatigue resistance.
- NACE MR0175 / ISO 15156 — Material qualification for sour service (H₂S-containing environments).
- 3-A Sanitary Standards — Food-grade equipment certification for dairy and beverage processing applications.
- PED Category II/III — Notified Body inspection and certification for pressure equipment up to specified capacity limits.
7. Unique Selling Points
Superior Thermal Performance: The dual-coil configuration provides approximately 40–60% greater heat transfer surface area compared to single-pass shell-and-tube designs of equivalent volume, resulting in higher U-values and reduced capital expenditure for thermal duty fulfillment.
Compact Footprint: The helical coil geometry within a cylindrical barrel enables high heat exchange capacity in minimal installation space, ideal for retrofit applications and space-constrained facilities.
Corrosion Resilience: Austenitic stainless steel coil tubes deliver 10–25 year service life in aggressive chemical environments without degradation of mechanical properties or surface integrity.
Customization Flexibility: Modular design allows tailoring of coil diameter, pitch, number of turns, and barrel dimensions to match specific thermal load requirements, flow rates, and pressure differentials.
Maintainability: Coil tubes can be individually extracted and replaced without dismantling the entire exchanger, minimizing maintenance downtime and lifecycle cost.
8. Conclusion
The Stainless Steel Coil Tube (Coiltube) product from Wenzhou Jixing Metal Materials Co., Ltd represents a state-of-the-art solution for industrial heat exchange applications demanding high thermal efficiency, corrosion resistance, and long-term reliability. Backed by rigorous manufacturing standards, comprehensive quality certifications, and decades of metallurgical expertise, this product delivers exceptional value across chemical, pharmaceutical, food processing, petrochemical, and energy sectors. The Double Coil Barrel Heat Exchanger architecture, leveraging precision-engineered austenitic stainless steel coil tubes, exemplifies the convergence of materials science and thermal engineering in modern process equipment design.