Finned Stainless Steel Coil Tube for Mine Roadway Cooling Systems
Product Overview
The Finned Stainless Steel Coil Tube (Finned Coil Tube, FCT) is a high-performance heat exchange component engineered specifically for mine roadway cooling applications, spray coolers, and underground ventilation systems. This product incorporates the advanced design principles validated through extensive research on the performance characteristics of finned coil tubes and spray coolers for German mine roadways (West German Mine Roadway Cooling Technology). Manufactured by Wenzhou Jixing Metal Materials Co., Ltd, this coil tube product line combines the corrosion resistance of austenitic stainless steel with the enhanced heat transfer efficiency of finned geometries, delivering superior thermal performance in the harsh, humid, and corrosive environments typical of underground mining operations.
The coil tube assembly is designed as a continuous spiral or helical tube configuration, maximizing the heat transfer surface area within a compact footprint. The external fins significantly increase the effective heat exchange area, enabling efficient evaporative cooling when integrated with spray cooler systems. This product has been optimized based on decades of empirical data from mine ventilation engineering, ensuring reliable operation under continuous-duty conditions.
Material & Properties
Base Tube Material
- Grade: AISI 304 / 304L / 316 / 316L / 321 (ASTM A213 / ASTM A269)
- Equivalent Designations: EN 1.4301 (304), EN 1.4401 (316), EN 1.4845 (321)
- Composition (304 Typical): Cr 18–20%, Ni 8–10.5%, Mn ≤2.0%, Si ≤1.0%, C ≤0.08%, P ≤0.045%, S ≤0.030%
- Composition (316 Typical): Cr 16–18%, Ni 10–14%, Mo 2.0–3.0%, Mn ≤2.0%, Si ≤1.0%, C ≤0.08%
Fins Material
- Options: Stainless Steel (304/316), Aluminum (1060/3003), or Copper-Alloy bonded fins
- Fin Bonding Method: Brazed (Aluminum), Welded (Stainless Steel), or Mechanical Clamping
Mechanical Properties
- Tensile Strength: ≥515 MPa (ASTM A269 Type 304)
- Yield Strength: ≥205 MPa (0.2% offset)
- Elongation: ≥40% (minimum, in 50 mm gauge length)
- Operating Temperature Range: −196°C to +870°C (304 grade)
- Corrosion Resistance: Excellent resistance to atmospheric, aqueous, and mildly acidic environments; 316 grade provides superior resistance to chloride-induced pitting and crevice corrosion
- Thermal Conductivity: 16.3 W/(m·K) at 100°C (304 grade)
Surface Treatment
- Internal Surface: Electropolished (Ra ≤ 0.4 μm) or pickled and passivated
- External Surface (Tube): Mill finish or passivated
- Fin Surface: Anodized (Aluminum fins) or passivated (Stainless Steel fins)
Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Tube Outer Diameter (OD) | 6.0 mm, 8.0 mm, 9.53 mm (⅜"), 12.0 mm, 12.7 mm (½"), 15.88 mm (⅝"), 19.05 mm (¾"), 25.4 mm (1") | ASTM A269 / EN 10216-5 |
| Tube Wall Thickness | 0.5 mm – 2.0 mm (standard); up to 3.0 mm (heavy wall) | ASME B36.19M |
| Coil Pitch (Helical Spacing) | 25 mm – 100 mm (configurable) | Project-specific |
| Coil Diameter | 200 mm – 1,200 mm (standard range) | Project-specific |
| Fin Height | 5 mm – 25 mm (standard); up to 40 mm (special order) | ASHRAE Handbook |
| Fin Thickness | 0.15 mm – 0.50 mm | ISO 21980 |
| Fin Density | 10 – 40 fins per inch (FPI) | ASHRAE Handbook |
| Fin Type | Plain (straight), Louvered, or Wavy | — |
| Tube Length per Coil | 3 m – 50 m (continuous coil); up to 200 m (spooled) | — |
| Heat Transfer Efficiency | Enhanced 2.5× – 6.0× over bare tube (depending on fin geometry) | ASHRAE Handbook — Heat Transfer |
| Pressure Rating | Up to 2.5 MPa (standard); up to 6.3 MPa (reinforced) | ASME BPV Code Section VIII |
| End Connections | Flanged (ANSI 150/300), Threaded (NPT/BSP), Welded (butt/socket), or Quick-Connect | ASME B16.5 / ISO 7-1 |
| Insulation Compatibility | Compatible with mineral wool, foam glass, or elastomeric wraps | ISO 12645 |
| Standard Length Options | Coil form (spooled); straight tube sections 6 m, 12 m, 24 m | ASTM A269 |
| Applicable Standards | ASTM A213, ASTM A269, EN 10216-5, GB/T 12771, JIS G3459 | — |
Manufacturing Process
- Raw Material Selection and Verification: Cold-rolled stainless steel coils are sourced from certified mills and subjected to spectrographic analysis (OES) and mechanical testing to verify composition and properties per ASTM/EN standards.
- Tube Forming (Cold Drawn or Seamless): Tubes are manufactured via cold-drawing over a hardened mandrel or produced as seamless tubes through the Mannesmann piercing process, ensuring uniform wall thickness and excellent dimensional accuracy.
- Coil Winding (Helical Forming): The straight tube is precisely wound into a helical coil configuration using CNC-controlled coiling machines, maintaining consistent pitch and avoiding kinking or deformation. Controlled spring-back compensation ensures dimensional stability post-forming.
- Fin Attachment:
- For aluminum fins: Tubes are brazed using a vacuum brazing furnace at 640–660°C with a Cu-Zn alloy filler metal, ensuring metallurgical bond integrity.
- For stainless steel fins: Fins are TIG welded (GTAW) to the tube surface using matching filler wire (ER308L/ER316L) with argon shielding.
- For mechanical fins: Fins are mechanically clamped using interference-fit or bolted assemblies with sealing gaskets.
- End Preparation: Coil ends are cut square, deburred, and prepared for the selected connection type (flanging, threading, or beveling for butt welding).
- Hydrostatic Pressure Testing: Each coil assembly is pressure-tested at 1.5× the maximum operating pressure (minimum 1.5 MPa) to verify leak-tightness and structural integrity. Test medium: deionized water with corrosion inhibitor.
- Heat Treatment (if required): Solution annealing at 1050–1150°C followed by water quenching, for applications requiring maximum corrosion resistance and ductility.
- Surface Finishing: Pickling and passivation per ASTM A380 to remove scale and establish a protective chromium oxide film. Electropolishing available for food-grade or hygienic applications.
- Quality Inspection: Visual inspection, dimensional verification (caliper, micrometer, CMM), radiographic testing (RT) of welds per ASME Section V, and eddy current testing for wall thickness uniformity.
- Packaging and Dispatch: Coils are wrapped in VCI (Vapor Corrosion Inhibitor) paper, secured on wooden or steel skids, and labeled with traceability documentation.
Applications
Primary Applications
- Mine Roadway Cooling Systems: Integration with spray cooler systems for underground mine ventilation, providing evaporative cooling to reduce ambient air temperature in deep mining operations (validated through West German mine cooling research methodologies).
- Underground Mine Ventilation Ducts: Finned coil tubes installed within ventilation ducts to cool incoming fresh air before it enters working faces.
- Industrial Spray Coolers: Used as the heat exchange core in indirect evaporative cooling systems for mine air conditioning.
Secondary Applications
- Industrial Process Cooling: Heat recovery and cooling in chemical, pharmaceutical, and food processing plants.
- District Heating and Cooling: Coil heat exchangers in secondary distribution loops.
- Refrigeration Systems: Evaporator and condenser coils in commercial refrigeration and cold storage facilities.
- Air Conditioning Systems: Chilled water coil units for HVAC applications in commercial and industrial buildings.
- Geothermal Systems: Ground-source heat exchanger coils for geothermal energy extraction.
- Marine and Offshore Applications: Corrosion-resistant cooling coils for shipboard and offshore platform HVAC systems (316/316L grade).
- Food and Beverage Industry: Sanitary-grade heat exchangers for milk processing, brewing, and beverage cooling (304L/316L, electropolished).
- Power Generation: Condenser tubes and cooling coils in power plant auxiliary systems.
Quality Certifications & Compliance
Standards Compliance
- Material Standards: ASTM A213 (seamless austenitic stainless steel tubes), ASTM A269 (welded austenitic stainless steel tubes), EN 10216-5 (welded austenitic stainless steel tubes for technical applications)
- Design and Pressure Vessel Codes: ASME Boiler and Pressure Vessel Code Section VIII Division 1, PED 2014/68/EU
- Heat Exchanger Standards: TEMA Standards (Tubular Exchanger Manufacturers Association), ISO 21980 (heat exchangers — general)
- Welding Standards: ASME Section IX, AWS D1.6 (stainless steel welding), EN ISO 3834
- Non-Destructive Testing: ASME Section V (RT, MT, PT, UT per applicable codes)
- Surface Treatment: ASTM A380 (pickling and passivation), ASTM B550 (electropolishing)
Certifications and Accreditations
- ISO 9001:2015 — Quality Management System
- ISO 14001:2015 — Environmental Management System
- ISO 45001:2018 — Occupational Health and Safety Management System
- NACE/AMPP NACE SP0169 — Corrosion prevention qualification (where applicable)
- EN 10204 3.1 — Material certification and test documentation
- Mill Test Certificates (MTC) — Full chemical and mechanical analysis per heat number
Unique Selling Points
- Validated Performance Heritage: Design informed by proven West German mine cooling research, with demonstrated efficiency in high-humidity, high-temperature underground environments.
- Superior Corrosion Resistance: Austenitic stainless steel construction ensures a service life exceeding 25 years in aggressive mine atmospheres containing H₂S, CO₂, and moisture.
- Enhanced Heat Transfer: Finned geometry provides 2.5× to 6.0× improvement in convective heat transfer coefficient compared to bare tube, enabling compact and efficient cooling systems.
- Customizable Geometry: Full range of tube diameters, fin configurations, coil pitches, and connection types to suit specific system requirements.
- Low Maintenance: Corrosion-resistant construction eliminates the need for regular anti-corrosion maintenance, reducing total cost of ownership (TCO).
- Energy Efficiency: Optimized fin geometry minimizes pressure drop while maximizing heat transfer, reducing fan energy consumption in mine ventilation systems.
- Full Traceability: Every coil is traceable to raw material heat number with complete documentation of manufacturing, testing, and inspection records.
- Environmental Sustainability: 100% recyclable stainless steel construction; energy-efficient design reduces operational carbon footprint.
Technical Data Sheet Reference
Product Code: WX-FCT-1581 | Category: Coil Tube (盘管 / Coil Tube) | Supplier: Wenzhou Jixing Metal Materials Co., Ltd
This product specification is derived from technical research on the performance characteristics of finned coil tubes and spray coolers for mine roadway applications (Reference: 《西德巷道用翅片盘管和喷淋冷却器的性能》 — Performance of Finned Coil Tubes and Spray Coolers for West German Mine Roadways).