Stainless Steel Coil Tube — Fan Coil Unit Plasma Air Disinfection Application
Product Overview
The Stainless Steel Coil Tube (Model No. 674) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered coil tube product designed for integration into fan coil unit (FCU) systems, particularly those incorporating plasma air disinfection technology. This product serves as a critical component in the thermal exchange and air treatment circuits of modern HVAC (Heating, Ventilation, and Air Conditioning) systems, where its unique geometry and material properties enable efficient heat transfer while maintaining structural integrity under prolonged operational stress.
The coil tube is specifically optimized for applications involving Plasma Air Disinfection mechanisms, where the tube's surface characteristics contribute to the overall efficiency of pathogen elimination and air purification processes within enclosed environments such as hospitals, laboratories, and cleanroom facilities.
Material & Properties
The coil tube is fabricated from high-grade Stainless Steel (AISI 304 / 316L), selected for its exceptional corrosion resistance, mechanical strength, and long-term durability in demanding environmental conditions.
- Base Material: Austenitic Stainless Steel (UNS S30408 / UNS S31603)
- Chromium Content (Cr): 18.0–20.0%
- Nickel Content (Ni): 8.0–10.5%
- Molybdenum Content (Mo, 316L grade): 2.0–3.0%
- Carbon Content (C): ≤0.03% (Low Carbon / L-grade)
- Surface Finish: BA (Bright Annealed) or No. 4 Brushed
- Hardness (HB): 137–200
- Tensile Strength (MPa): 520–720
- Yield Strength (MPa): ≥205
- Thermal Conductivity (W/m·K): 14.9–16.3
- Corrosion Resistance: Excellent resistance to chlorides, acids, and alkaline solutions
- Operating Temperature Range: −196°C to +870°C
Specifications
| Parameter | Specification | Unit |
|---|---|---|
| Product Model | No. 674 Coil Tube | — |
| Outer Diameter (OD) | 6.0 – 12.7 | mm |
| Wall Thickness | 0.5 – 1.5 | mm |
| Coil Length | Customizable (Standard: 3 – 10) | m |
| Coil Pitch (Spacing) | 2.0 – 5.0 | mm |
| Winding Diameter | 50 – 200 | mm |
| Material Grade | SUS 304 / SUS 316L / Custom Alloy | — |
| Surface Treatment | BA / 2B / Electropolished / Passivated | — |
| Maximum Working Pressure | 1.6 – 4.0 | MPa |
| Dimensional Tolerance (OD) | ±0.05 | mm |
| Dimensional Tolerance (Wall) | ±0.03 | mm |
| Coating (Optional) | PVD / Anodized / None | — |
| End Treatment | Cut / Flanged / Threaded / Brazed | — |
| Compliance Standard | ASTM A213 / ASTM A269 / EN 10216-5 | — |
Manufacturing Process
The production of the No. 674 Stainless Steel Coil Tube follows a rigorous multi-stage manufacturing protocol to ensure dimensional accuracy, surface quality, and mechanical performance:
- Raw Material Selection: High-purity stainless steel strip (coil) conforming to ASTM A240 or EN 10088-2 standards, with certified chemical composition and mechanical properties.
- Slitting & Leveling: Precision slitting of the master coil to required width, followed by mechanical leveling to eliminate residual stresses and ensure flatness.
- Forming & Coiling: The leveled strip is fed through a series of precision rollers (coiling machine) to form the helical coil geometry. Controlled winding tension ensures uniform pitch and diameter tolerances.
- Welding (if applicable): Spiral-welded tubes undergo TIG (Tungsten Inert Gas) or orbital welding with 100% argon shielding to prevent oxidation and ensure weld integrity.
- Heat Treatment: Solution annealing at 1050–1150°C followed by rapid quenching to achieve full austenitic structure, maximizing corrosion resistance and ductility.
- Surface Finishing: Bright annealing (BA) in a protective atmosphere, followed by mechanical polishing or electropolishing to achieve Ra ≤ 0.4 μm surface roughness.
- Passivation: Chemical passivation treatment (nitric acid or citric acid based) to enhance the chromium oxide passive layer and improve corrosion resistance.
- Quality Inspection: Non-destructive testing (NDT) including eddy current testing, hydrostatic pressure testing, and visual inspection of all critical dimensions.
Applications
The No. 674 Stainless Steel Coil Tube is engineered for high-performance applications, particularly in:
- Fan Coil Unit (FCU) Systems: Integration into air handling units for thermal exchange in commercial and industrial HVAC systems.
- Plasma Air Disinfection Systems: Serving as the structural and thermal conduit within plasma-based air purification devices, where the stainless steel surface resists degradation from reactive oxygen species (ROS) and ozone generated during the disinfection process.
- Medical & Pharmaceutical HVAC: Hospital operating rooms, cleanrooms (ISO 5–7), and pharmaceutical manufacturing facilities requiring GMP (Good Manufacturing Practice) compliant air systems.
- Food & Beverage Industry: Processing plants where sanitary-grade tubing is mandatory for air cooling and temperature control systems.
- Electronics Cooling: Heat exchangers for server rooms, data centers, and sensitive electronic equipment.
- Marine & Offshore: Corrosion-resistant heat exchange coils in marine HVAC and desalination systems.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and holds the following certifications to ensure product reliability and international compliance:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System
- ISO 45001:2018 — Occupational Health and Safety Management System
- CE Marking — Conformity with European health, safety, and environmental protection standards
- ASTM Compliance — ASTM A213, A269, A240 material specifications
- EN 10204 3.1 — Material Test Certificate (Mill Certificate)
- SGS / Intertek Testing — Third-party material and dimensional verification
- RoHS & REACH Compliance — Restriction of Hazardous Substances and Chemical Regulation compliance
Unique Selling Points
The No. 674 Stainless Steel Coil Tube from Wenzhou Jixing Metal Materials Co., Ltd. distinguishes itself through several key advantages:
- Plasma-Resistant Surface: The electropolished and passivated surface maintains integrity under repeated plasma discharge cycles, preventing surface degradation that would compromise disinfection efficiency over time.
- Precision Winding Geometry: Advanced CNC-controlled coiling ensures consistent pitch and diameter, optimizing airflow dynamics and heat transfer efficiency in FCU applications.
- Superior Corrosion Resistance: The 316L-grade option with molybdenum alloying provides exceptional resistance to chlorinated disinfectant residues commonly found in medical air systems.
- Full Traceability: Each batch is accompanied by a complete material traceability record, including mill certificates, chemical analysis reports, and mechanical test data.
- Customization Capability: Flexible manufacturing parameters allow tailoring of coil dimensions, material grades, and surface finishes to meet specific OEM (Original Equipment Manufacturer) requirements.
- Long Service Life: Expected operational lifespan exceeding 15 years under normal conditions, significantly reducing maintenance costs and system downtime.
Conclusion
The No. 674 Stainless Steel Coil Tube represents a state-of-the-art solution for integrating thermal management and air disinfection functionality within modern HVAC systems. Its combination of premium material selection, precision manufacturing, and rigorous quality assurance positions it as an ideal component for applications demanding reliability, hygiene, and long-term performance in critical environments.