Stainless Steel Coil Tube (Coiltube) — Internal/External Cooling Coil Application
Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered product specifically designed for heat exchange and thermal management applications. This product is primarily employed in low-pressure steam condensate tanks where internal and external coil configurations are utilized to facilitate efficient cooling and condensation processes. The coil tube serves as a critical component in thermal systems, enabling the transfer of heat between process fluids and cooling media through its coiled geometry, which maximizes surface area within a compact footprint.
This product (Catalog No. 243) is categorized under the literature and technical reference division, indicating its association with documented engineering design practices and verified application methodologies in industrial thermal systems.
Material & Properties
The coil tube is fabricated from high-grade stainless steel, offering superior corrosion resistance, thermal conductivity, and mechanical durability. Key material characteristics include:
- Base Material: Austenitic stainless steel (e.g., SUS304 / SUS316 / SUS316L), selected for their excellent resistance to pitting, crevice corrosion, and general chemical attack in condensate and steam environments.
- Thermal Conductivity: Approximately 16.3 W/(m·K) for SUS304 and 16.3 W/(m·K) for SUS316, ensuring efficient heat transfer performance.
- Operating Temperature Range: Suitable for continuous service from cryogenic temperatures up to 800°C (1,472°F), well within the parameters of low-pressure steam systems.
- Mechanical Properties: Minimum yield strength of 205 MPa (SUS304) with elongation ≥ 40%, providing adequate resistance to thermal cycling fatigue.
- Surface Finish: Available in mill finish, electropolished, or passivated surface treatments to minimize biofilm formation and facilitate cleaning in process applications.
- Hygienic Compliance: Surface roughness (Ra) as low as 0.4 µm available for sanitary applications.
Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) | — |
| Catalog Number | 243 | Wenzhou Jixing Metal Materials Co., Ltd. |
| Outer Diameter (OD) | 6 mm – 38 mm (customizable) | EN 10217 / ASTM A269 |
| Wall Thickness | 0.5 mm – 2.0 mm | EN 10217-1 |
| Coil Pitch (Spacing) | 10 mm – 50 mm (configurable per design) | ASME PT-2 |
| Coil Diameter (Bundle) | 50 mm – 500 mm (application-dependent) | Custom / Engineering Drawings |
| Coil Length (Uncoiled) | 1 m – 50 m (continuous) | — |
| End Connections | Threaded, welded, flanged, or sanitary tri-clamp | ASME B1.20.1 / EN 1092 |
| Maximum Operating Pressure | Up to 1.6 MPa (low-pressure steam system) | ASME BPV Code Section VIII |
| Design Pressure (Test) | 1.5 × Maximum Operating Pressure | ASME BPV Code |
| Heat Transfer Coefficient | 500 – 2,500 W/(m²·K) (typical, fluid-dependent) | Engineering Calculation |
| Applicable Standards | ASTM A269, ASTM A213, EN 10217-1, EN 10216-5 | International |
| Application Reference | Low-Pressure Steam Condensate Tank (Internal & External Coil Cooling) | Technical Literature |
Manufacturing Process
The production of the stainless steel coil tube follows a rigorous multi-stage manufacturing protocol to ensure dimensional accuracy, material integrity, and performance reliability:
- Material Selection & Inspection: Certified stainless steel seamless or welded pipe is procured with full material traceability. Incoming inspection includes chemical composition analysis (OES), mechanical testing, and visual examination in accordance with ASTM A213/A269 requirements.
- Material Preparation: Raw pipe is cut to specified lengths, deburred, and end-prepped. Surface decontamination is performed to remove oils, oxides, and handling residues.
- Coil Forming: Precision CNC-driven coil winding machines form the tube into the required helical geometry. The forming process maintains a uniform coil pitch and diameter within ±0.5 mm tolerance. Cold-forming is employed to avoid material stress sensitization, preserving the austenitic microstructure.
- Heat Treatment (if required): Solution annealing at 1050–1150°C followed by rapid water quenching may be applied to restore full solution-treated condition and eliminate residual stresses from forming.
- Welding & Assembly: End connections are fabricated using orbital TIG (GTAW) welding with argon back-purging to ensure full penetration and oxidation-free weld interiors. Weld quality is verified per ASME Section IX qualification procedures.
- Passivation & Surface Treatment: The finished coil tube undergoes chemical passivation (nitric acid or citric acid bath) to restore the passive chromium oxide film, enhancing long-term corrosion resistance.
- Pressure Testing: Each coil tube assembly is subjected to hydrostatic pressure testing at 1.5× the maximum operating pressure, with a minimum hold time of 30 minutes to verify leak-tightness and structural integrity.
- Final Inspection & Documentation: Non-destructive testing (NDT) including visual examination (VT), dye penetrant testing (PT), and dimensional verification is performed. Full quality documentation is compiled including material certificates, weld maps, and test reports.
Applications
The stainless steel coil tube is engineered for a wide range of industrial and process applications, with particular emphasis on thermal management systems:
- Low-Pressure Steam Condensate Tanks: Internal and external coil configurations facilitate rapid cooling of high-temperature condensate, enabling efficient heat recovery and minimizing thermal shock to the tank structure. This is the primary documented application referenced in the product literature.
- Process Heat Exchangers: Used as coil bundles in shell-and-coil heat exchangers for fluid-to-fluid heat transfer in chemical, pharmaceutical, and food processing industries.
- Refrigeration & Cooling Systems: Employed as evaporator coils in industrial refrigeration systems where stainless steel's corrosion resistance is essential.
- Boiler Auxiliary Systems: Integrated into economizers, air preheaters, and condensate recovery systems in steam generation plants.
- Pharmaceutical & Bioprocessing: Sanitary-grade coil tubes used in CIP (Clean-in-Place) and SIP (Sterilize-in-Place) compatible thermal processing equipment.
- Food & Beverage Industry: Cooling coils in pasteurization systems, beverage chilling, and dairy processing equipment.
- Marine & Offshore Systems: Condensate cooling coils in marine boiler systems and offshore platform utility systems where chloride-resistant grades (SUS316L) are specified.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality management systems and certifications to ensure product conformity with international standards:
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and process control.
- ISO 14001:2015 — Environmental Management System certification demonstrating commitment to environmentally responsible manufacturing.
- ASME "U" Stamp — Authorization to manufacture pressure-containing components in compliance with ASME Boiler and Pressure Vessel Code.
- EN 10204 3.1 / 3.2 — Material test certificates issued per European standard for product verification and traceability.
- CE Marking — Conformity with European Machinery Directive and Pressure Equipment Directive (PED 2014/68/EU) where applicable.
- Material Traceability: Full mill certificate traceability from raw material through final product, with lot-specific chemical and mechanical test data.
- NDT Qualification: In-house NDT personnel certified to ASNT Level II/III or equivalent for visual, penetrant, and ultrasonic examination.
Unique Selling Points
1. Application-Validated Design: This coil tube product is directly referenced in published engineering literature on low-pressure steam condensate tank design, demonstrating proven performance in real-world thermal management applications.
2. Custom Geometry Engineering: Coil pitch, bundle diameter, and configuration (internal/external) are tailored to specific heat transfer requirements, enabling optimized thermal performance for each application.
3. Dual-Configuration Versatility: Available for both internal and external coil installation, providing design flexibility for condensate tanks, heat exchangers, and process vessels.
4. Full Material Traceability: Every coil tube is accompanied by complete material documentation, ensuring compliance with regulatory and audit requirements.
5. Precision Manufacturing: CNC-driven coil forming ensures dimensional consistency and repeatable performance across production batches.
Technical Notes
The design and selection of internal versus external coil configurations in condensate tanks is governed by the thermal load, available space, fluid flow characteristics, and maintenance accessibility requirements. Internal coils provide direct contact with the condensate, maximizing heat transfer efficiency, while external coils offer easier maintenance access and reduce the risk of internal fouling. Engineering calculations for coil sizing should consider the Logarithmic Mean Temperature Difference (LMTD), overall heat transfer coefficient (U-value), and required heat duty to ensure adequate performance margins.