Stainless Steel Coil Tube (Coiltube) for Aquaculture Temperature Regulation Systems
Product Overview
The Stainless Steel Coil Tube (Coiltube), product catalog No. 901, is a precision-engineered coiled tubing solution manufactured by Wenzhou Jixing Metal Materials Co., Ltd. Specifically designed for thermal regulation applications in industrial and factory-based aquaculture systems, this product delivers superior heat exchange performance while maintaining long-term structural integrity in corrosive aquatic environments. The coil tube serves as the core heat transfer medium in pond temperature control systems, enabling precise water temperature management critical for optimal marine organism growth and survival rates.
This product has been validated through comparative economic and performance studies conducted in real-world factory farming installations, including case studies in coastal aquaculture communities in Ningbo, China. The research demonstrated that stainless steel coil tubes offer significantly superior cost-effectiveness, durability, and thermal efficiency compared to alternative material options (such as PVC or aluminum coils) in prolonged submerged service conditions.
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, typically conforming to the following material specifications:
- Primary Material Grade: SUS304 / ASTM A269 TP304 (18% Cr, 8% Ni) for standard aquaculture applications
- Corrosion-Resistant Grade: SUS316L / ASTM A269 TP316L (16.5% Cr, 10% Ni, 2% Mo) for high-chloride marine environments
- Alternative Grade: SUS321 / ASTM A269 TP321 (Ti-stabilized) for elevated temperature cycling applications
Key Material Properties:
- Corrosion Resistance: Excellent resistance to pitting, crevice corrosion, and intergranular corrosion in chloride-rich seawater and freshwater aquaculture environments
- Thermal Conductivity: 14.9–16.3 W/(m·K) at 20°C, providing efficient heat transfer between the heating/cooling medium and the aquaculture water
- Operating Temperature Range: -196°C to +870°C (material limit); practical aquaculture application range of 0°C to 60°C
- Mechanical Strength: Tensile strength ≥ 520 MPa; Yield strength ≥ 205 MPa (SUS304)
- Non-Toxicity: Food-grade compliant; no leaching of harmful substances into aquaculture water
- Hygienic Surface: Ra ≤ 0.5 μm finish, preventing biofilm accumulation and microbial growth
Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Outer Diameter (OD) | Φ12 mm / Φ16 mm / Φ20 mm / Φ25 mm / Φ32 mm (customizable) | ASTM A269 / GB/T 14976 |
| Wall Thickness (WT) | 0.5 mm / 0.8 mm / 1.0 mm / 1.2 mm / 1.5 mm | ASTM A269 / GB/T 14976 |
| Coil Diameter | Φ150 mm – Φ600 mm (adjustable per installation) | Manufacturer specification |
| Coil Length per Spool | 50 m / 100 m / 200 m / 500 m (customizable) | — |
| Material Grade | SUS304 / SUS316L / SUS321 | JIS G4305 / ASTM A240 |
| Surface Finish | 2B / BA / No. 4 Brushed / Polished (Ra ≤ 0.5 μm) | ASTM A478 |
| Welding Method | Orbital TIG (GTAW) / Laser welding | ISO 13919 |
| Maximum Working Pressure | 1.0 – 2.5 MPa (depending on OD and WT) | ASME B31.3 |
| Maximum Flow Velocity | 2.0 – 3.0 m/s (recommended) | — |
| End Connection Type | Butt weld / Threaded (BSP/NPT) / Flanged / Quick-coupling | ISO 7-1 / ASME B1.20.1 |
| Coating (Optional) | PASSivated / Epoxy-coated / None | — |
| Service Life | ≥ 15 years in freshwater; ≥ 10 years in marine environment | — |
Manufacturing Process
The production of the stainless steel coil tube follows a rigorous multi-stage manufacturing process to ensure dimensional accuracy, mechanical integrity, and corrosion resistance:
- Raw Material Selection: Cold-rolled stainless steel strip is sourced from certified mill producers, verified through mill test certificates (MTC) and spectrographic analysis for chemical composition compliance.
- Slitting & Leveling: The strip is slit to precise width and leveled to eliminate residual stress and ensure uniform material properties.
- Coiling (Tube Forming): The leveled strip is wound through precision forming rollers to create the required tube diameter and wall thickness, with continuous dimensional monitoring via laser measurement systems.
- Seam Welding: A longitudinal seam is created using orbital TIG welding (GTAW) or high-frequency induction welding under inert gas (argon) shielding to prevent oxidation. Weld quality is verified through dye penetrant testing (DPT) and hydrostatic pressure testing.
- Heat Treatment (if required): For stabilized grades (SUS321), a solution annealing treatment at 1050°C–1100°C with rapid water quenching is performed to restore full austenitic microstructure and maximum corrosion resistance.
- Surface Finishing: The welded tube undergoes mechanical or chemical surface treatment (pickling, passivation, or polishing) to achieve the specified surface roughness and remove mill scale or heat tint.
- Coil Winding: The finished tube is wound into the required coil configuration using CNC-controlled winding equipment to maintain uniform coil spacing and prevent deformation or kinking.
- Quality Inspection: Final inspection includes dimensional verification (OD, WT, coil diameter), hydrostatic pressure testing at 1.5× working pressure for 30 seconds, visual examination of welds, and material traceability documentation.
Applications
The Stainless Steel Coil Tube is primarily engineered for thermal management in factory-based aquaculture systems, with the following key application domains:
- Marine Aquaculture Pond Temperature Control: Serving as heat exchange coils in recirculating aquaculture systems (RAS) and open-pond marine farming installations, providing precise water temperature regulation for species such as Japanese eel, sea bass, sea bream, and shrimp.
- Offshore Fishing Village Installations: As validated in the Ningbo coastal aquaculture case study, the coil tube integrates into community-scale farming operations where space is limited and durability against saltwater corrosion is paramount.
- Industrial Greenhouse Aquaponics: Temperature regulation in integrated aquaponic systems combining aquaculture with hydroponic crop production.
- Seafood Processing & Cold Chain: Heat transfer applications in seafood processing facilities requiring food-grade, corrosion-resistant tubing.
- Geothermal Aquaculture Heating: Utilizing geothermal energy sources for pond heating in cold-climate regions, where the coil tube interfaces with geothermal fluid circuits.
- General Industrial Heat Exchange: Applicable to chemical processing, pharmaceutical manufacturing, and food & beverage production requiring sanitary-grade tubing.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains the following quality assurance and compliance certifications for its stainless steel coil tube products:
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and process control
- ISO 14001:2015 — Environmental Management System certification for sustainable manufacturing practices
- CE Marking — European Conformity certification for products exported to the European Economic Area
- Mill Test Certificate (MTC / EN 10204 3.1) — Full traceability documentation for each production batch including chemical composition, mechanical properties, and heat number
- NSF / FDA Compliance — Material certification confirming food-contact safety for aquaculture and food processing applications
- Pressure Vessel Testing — Hydrostatic pressure testing per ASME B31.3 and PED (Pressure Equipment Directive 2014/68/EU) requirements where applicable
- NACE MR0175 / ISO 15156 — Compliance for sour service applications in high-chloride marine environments
Unique Selling Points
Economically Superior Long-Term Performance: Comparative economic analysis conducted in Ningbo marine aquaculture installations demonstrated that stainless steel coil tubes, despite higher initial investment compared to PVC alternatives, achieve a significantly lower total cost of ownership (TCO) over a 10–15 year service life due to elimination of replacement cycles, minimal maintenance requirements, and sustained thermal efficiency.
- Exceptional Corrosion Durability: SUS316L grade offers superior resistance to chloride-induced pitting corrosion in marine environments, eliminating the primary failure mode of alternative materials
- Hygienic & Non-Toxic: Certified food-grade material ensures zero contamination risk to cultured organisms and harvested products
- Customizable Configuration: Full range of OD, wall thickness, coil diameter, and spool length options to match specific pond geometry and thermal load requirements
- High Thermal Efficiency: Stainless steel's favorable thermal conductivity combined with the high surface-area-to-volume ratio of coiled geometry maximizes heat exchange rates
- Factory-Validated Performance: Backed by empirical economic and performance data from real-world aquaculture installations, providing confidence in ROI projections
- Low Maintenance: Passive corrosion protection eliminates need for cathodic protection systems or periodic replacement, reducing operational downtime and labor costs