Stainless Steel Coil Tube (盘管) for Ultra-High Temperature Sterilization Systems
Product Overview
The Stainless Steel Coil Tube (Coil Tube) is a precision-engineered heat exchange component manufactured by Wenzhou Jixing Metal Materials Co., Ltd. (Wenzhou Jixing Metal Materials Co., Ltd.), specifically designed for ultra-high temperature sterilization (UHT) equipment and industrial heat transfer applications. As a critical element in continuous sterilization systems, the coil tube provides superior thermal efficiency, extended heat transfer surface area, and exceptional resistance to thermal stress cycling — making it a preferred alternative to conventional shell-and-tube heat exchangers in high-temperature processing environments.
Unlike traditional shell-and-tube configurations, the coil tube design maximizes the heat exchange surface-to-volume ratio, enabling rapid and uniform temperature transfer across the full length of the coiled element. This geometry is particularly advantageous in applications requiring rapid heating, pasteurization, or sterilization cycles where thermal consistency is paramount.
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, selected for its outstanding combination of corrosion resistance, mechanical strength, and thermal stability under extreme operating conditions.
- Primary Grades: SUS 304 (ASTM 304), SUS 316L (ASTM 316L), SUS 321 (ASTM 321), and SUS 310S (ASTM 310S)
- Chromium Content: 18%–26% Cr, providing robust passive oxide film formation
- Nickel Content: 8%–26% Ni, ensuring austenitic microstructure stability at elevated temperatures
- Molybdenum Addition (316L/310S): 2%–3% Mo, enhancing resistance to pitting and crevice corrosion
- Operating Temperature Range: −196°C to +1100°C (depending on grade)
- Maximum UHT Sterilization Temperature: Up to 151°C (304°F) sustained, with peak excursions to 180°C (356°F)
- Surface Finish: Electropolished (EP) or passivated, with surface roughness Ra ≤ 0.4 μm for sanitary-grade applications
- Welding Compatibility: TIG (GTAW) welding with argon shielding; weld seam quality per AWS D1.6
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (盘管 / Coil Tube) |
| Catalog No. | 549 |
| Tube Outer Diameter (OD) | Φ6 mm – Φ50 mm (customizable) |
| Wall Thickness | 0.5 mm – 3.0 mm |
| Coil Pitch / Spacing | 8 mm – 25 mm (adjustable per design) |
| Coil Diameter | Φ100 mm – Φ600 mm |
| Tube Length (Total) | 5 m – 50 m (custom configuration) |
| Applicable Standards | GB/T 14976, ASTM A269, ASTM A213, EN 10216-5, JIS G3459 |
| Pressure Rating | Up to 1.6 MPa (design pressure); test pressure 2.4 MPa |
| Heat Transfer Coefficient | Enhanced by 30%–50% compared to straight-tube equivalent |
| Surface Treatment | Acid pickling, passivation, electropolishing (optional) |
| End Connections | Welded, threaded (NPT/BSP), flanged, or sanitary tri-clamp |
| Sanitary Grade | Available in FDA-compliant and 3-A Sanitary Standards compliant versions |
Manufacturing Process
The production of stainless steel coil tubes at Wenzhou Jixing Metal Materials Co., Ltd. follows a rigorous multi-stage process to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Selection: Hot-rolled or cold-rolled stainless steel coils sourced from certified mills, with full mill test certificates (MTC) per EN 10204 Type 3.1.
- Coil Winding / Forming: Precision CNC-guided winding machines shape the tube into the specified helical geometry with controlled pitch, diameter, and spring-back compensation. Automated tension control ensures uniform winding density.
- Welding: Continuous helical welds or butt-welded joints are performed using argon-shielded TIG (GTAW) welding. Weld parameters are calibrated per AWS D1.6 to minimize heat-affected zone (HAZ) distortion.
- Stress Relief Annealing: Solution annealing at 1050°C–1150°C followed by controlled cooling to eliminate residual stresses introduced during cold forming and welding.
- Surface Treatment: Acid pickling removes oxide scales; subsequent passivation with nitric or citric acid solutions establishes a stable chromium oxide passive layer. Electropolishing is available for food-grade and pharmaceutical applications.
- Quality Inspection: Each coil tube undergoes dimensional verification (OD, wall thickness, pitch, total length), hydrostatic pressure testing (1.5× working pressure), and visual inspection. Spectroscopic analysis (PMI) confirms material grade compliance.
- Final Packaging: Tubes are protected with anti-corrosion packaging, wooden crates, or export-grade containers to prevent mechanical damage and contamination during transit.
Applications
The stainless steel coil tube is widely deployed across industries requiring high-efficiency heat exchange and thermal processing:
- Ultra-High Temperature (UHT) Sterilization: Continuous sterilization of dairy products (milk, cream, whey), fruit juices, and liquid foods at temperatures of 135°C–151°C for 2–5 seconds, ensuring commercial sterility while preserving nutritional and sensory qualities.
- Shell-and-Coil Heat Exchanger Comparison: Coil tubes offer advantages over shell-and-tube designs in terms of compact footprint, reduced fouling, and enhanced heat transfer — particularly in applications with high viscosity fluids or where CIP (Clean-in-Place) is required.
- Dairy and Beverage Processing: Pasteurization, sterilization, and heat recovery systems in milk processing plants, brewery equipment, and beverage concentration units.
- Pharmaceutical Industry: Steam sterilization loops, reactor jacket coils, and fluid heating circuits requiring GMP-compliant sanitary construction.
- Chemical and Petrochemical: Heat exchangers for corrosive media, condensation coils, and evaporator systems operating under high pressure and temperature.
- Food Processing Equipment: Kettle coil heating elements, retort heating circuits, and continuous flow pasteurizers.
- HVAC and Refrigeration: Condenser and evaporator coils in industrial refrigeration systems.
Comparison: Coil Tube vs. Shell-and-Tube Heat Exchangers for UHT Sterilization
Based on comparative analysis of shell-and-tube (列管) and coil tube (盘管) configurations in ultra-high temperature sterilization equipment, the following technical advantages are attributed to the coil tube design:
| Performance Parameter | Shell-and-Tube (列管) | Coil Tube (盘管) |
|---|---|---|
| Heat Transfer Surface Density | Standard | 30%–50% higher |
| Fluid Fouling Resistance | Higher fouling tendency | Reduced fouling due to turbulent flow in coil geometry |
| CIP (Clean-in-Place) Compatibility | Limited accessibility | Superior — open geometry facilitates complete cleaning |
| Footprint / Space Efficiency | Larger overall dimensions | Compact, space-saving design |
| Thermal Stress Tolerance | Prone to tube-to-tubesheet stress | Flexible helical geometry absorbs thermal expansion |
| Manufacturing Complexity | Lower (standardized) | Higher (precision winding required) |
| Cost Efficiency (Long-Term) | Higher maintenance costs | Lower lifecycle cost due to reduced cleaning and replacement frequency |
Unique Selling Points
- Superior Thermal Performance: The helical coil geometry induces secondary flow (Dean vortices), significantly enhancing convective heat transfer coefficients and reducing the overall heat transfer area requirement.
- Thermal Stress Resilience: The inherent flexibility of the coiled configuration accommodates differential thermal expansion between tube and housing, minimizing fatigue failure risk during repeated UHT cycles.
- Sanitary Design Excellence: Available in electropolished finish with Ra ≤ 0.4 μm, fully compliant with FDA 21 CFR Part 117, 3-A Sanitary Standards, and EHEDG guidelines for food-grade applications.
- Customizable Geometry: Wenzhou Jixing Metal Materials Co., Ltd. offers fully customizable coil dimensions — pitch, diameter, tube length, and wall thickness — tailored to specific equipment OEM requirements.
- Multi-Grade Availability: From standard 304 for general food processing to high-temperature 310S for extreme thermal applications, ensuring material suitability across diverse operating environments.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality management systems and holds the following certifications and complies with international standards:
- ISO 9001:2015 — Quality Management System certification
- ISO 14001 — Environmental Management System
- CE Marking — Conformity with European machinery and pressure equipment directives
- EN 10204 Type 3.1 — Inspection certificates for material traceability
- ASME Section VIII — Pressure vessel and heat exchanger components (where applicable)
- FDA Compliance — Food-contact materials certified per 21 CFR
- 3-A Sanitary Standards — For dairy and food processing equipment
- RoHS & REACH — Environmental compliance for EU market
Technical Note: The coil tube (盘管) design, as analyzed in the comparative study of shell-and-tube versus coil configurations for UHT sterilization equipment, demonstrates a compelling balance between thermal efficiency, mechanical durability, and operational maintainability. For OEMs and system integrators designing continuous sterilization lines, the coil tube represents a technically superior and economically viable solution — particularly in applications demanding rapid thermal response, minimal fouling accumulation, and seamless integration with CIP/SIP (Sterilization-in-Place) protocols.