Stainless Steel Coil Tube (盘管) — Model No. JX-CT Series
Product Overview
The Stainless Steel Coil Tube (盘管, Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered heat exchange component designed for integration into Continuous Stirred Tank Reactors (CSTR) and analogous process equipment. This product is fabricated from high-grade austenitic stainless steel and formed into a compact spiral or helical coil configuration, enabling efficient thermal transfer within confined vessel geometries.
Coil tubes serve as internal heat exchange surfaces within stirred tanks, where they facilitate controlled heating or cooling of process fluids through a working medium (typically water, steam, or thermal oil) circulated through the coil. The compact surface-to-volume ratio inherent to the coiled geometry provides superior heat transfer performance compared to flat plate or jacketed alternatives, making them indispensable in chemical processing, pharmaceutical manufacturing, and food-grade applications.
Material & Properties
The coil tube is constructed from premium austenitic stainless steel grades selected for their exceptional corrosion resistance, mechanical integrity, and thermal stability across a wide operating range.
- Primary Material Grades: SUS304 (ASTM A312 TP304), SUS316L (ASTM A312 TP316L), and SUS321 (ASTM A312 TP321)
- Corrosion Resistance: Superior resistance to oxidation, pitting, and crevice corrosion in aggressive chemical environments, particularly in the presence of chlorides (316L grade)
- Thermal Conductivity: 14–16 W/(m·K) for SUS304; 13–15 W/(m·K) for SUS316L
- Operating Temperature Range: −196°C to +870°C (SUS304); −196°C to +800°C (SUS316L)
- Mechanical Properties: Tensile strength ≥ 520 MPa; Yield strength ≥ 205 MPa; Elongation ≥ 40%
- Surface Finish: Electropolished or mechanically polished to Ra ≤ 0.4 μm for hygienic and pharmaceutical applications
Specifications
| Parameter | Specification |
|---|---|
| Tube Outer Diameter (OD) | Φ8 mm – Φ50 mm (customizable) |
| Tube Wall Thickness | 0.5 mm – 3.0 mm |
| Coil Diameter | Φ100 mm – Φ2000 mm |
| Coil Height | 50 mm – 1500 mm |
| Coil Turn Spacing | 10 mm – 50 mm (adjustable per thermal load requirement) |
| Total Coil Length | 1 m – 100 m (configurable) |
| End Connections | Flanged (ASME B16.5), Threaded (NPT/BSP), Socket Weld, or Sanitary Tri-Clamp |
| Maximum Working Pressure | Up to 2.5 MPa (365 psi) depending on wall thickness |
| Pressure Test Rating | 1.5× Maximum Working Pressure (per ASME Section VIII) |
| Heat Transfer Coefficient | 500 – 2,500 W/(m²·K) (dependent on fluid velocity and coil geometry) |
| Applicable Standards | ASTM A312, ASME B31.3, EN 10217, GB/T 12771 |
| Surface Treatment | Passivated, Electropolished, or Bead Blasted |
Manufacturing Process
The production of the JX-CT Series coil tube follows a rigorously controlled multi-stage manufacturing workflow:
- Material Selection & Inspection: Raw stainless steel tubes are sourced from certified mills and subjected to spectroscopic analysis (OES), ultrasonic testing, and dimensional verification prior to processing.
- Tube Straightening & Annealing: Incoming tubes undergo cold straightening followed by solution annealing at 1050–1150°C with rapid water quenching to restore full austenitic microstructure and eliminate residual stresses.
- Coil Forming: Precision CNC-driven cold coiling machines form the straight tube into the specified helical geometry. The forming process is carefully controlled to avoid work hardening and dimensional deviation, with bending radius ratios (R/D) maintained at ≥ 3.0 for structural integrity.
- Welding & Joining: End connections are fabricated using Gas Tungsten Arc Welding (GTAW/TIG) with inert gas shielding (Argon or Helium) to ensure penetration quality and minimize oxidation. Welds are performed in accordance with ASME Section IX qualified procedures.
- Surface Finishing: Electropolishing removes the cold-worked surface layer (10–25 μm), achieving a smooth, passive surface free of embedded contaminants. Final passivation with citric acid or nitric acid solutions establishes a stable chromium oxide protective layer.
- Quality Inspection & Testing: Completed assemblies undergo hydrostatic pressure testing, radiographic examination (RT) or ultrasonic testing (UT) of welds, dimensional inspection, and surface roughness verification.
Applications
The JX-CT Series stainless steel coil tube is engineered for demanding process environments where reliable heat exchange within confined reactor volumes is critical:
- Chemical Processing: Internal heating/cooling coils in CSTRs for polymerization reactions, esterification, and exothermic/endothermic chemical synthesis. Research on Residence Time Distribution (RTD) in coil-equipped stirred tanks demonstrates that coil geometry significantly influences fluid mixing patterns and reaction selectivity.
- Pharmaceutical Manufacturing: GMP-compliant reactors requiring precise temperature control for crystallization, fermentation, and bioprocessing operations.
- Food & Beverage Industry: Pasteurization, sterilization, and thermal processing equipment requiring hygienic-grade construction and easy-cleanability.
- Petrochemical & Refining: Catalyst cooling coils in continuous reactors and heat recovery systems.
- Environmental Engineering: Wastewater treatment reactors requiring corrosion-resistant internal heat exchange surfaces.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality management and product certification systems:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System Certification
- ASME "U" Stamp — National Board Registration for Pressure Vessel Components
- CE Marking — Compliance with European Pressure Equipment Directive (PED 2014/68/EU)
- GB/T 19001 — Chinese National Standard Quality System
- Third-Party Inspection: Available upon request (TÜV, SGS, Lloyd's Register)
- Material Traceability: Full Mill Test Reports (MTR) and Chemical Composition Certificates provided with every batch
Unique Selling Points
Superior Thermal Performance in Compact Geometry: The helical coil design maximizes heat transfer surface area within minimal reactor volume, achieving heat transfer coefficients up to 2,500 W/(m²·K) — significantly outperforming conventional jacketed vessel designs.
Proven Performance in RTD Applications: Extensive research literature (including studies on Residence Time Distribution under varying impeller configurations) confirms that coil tubes in CSTRs provide predictable and controllable thermal profiles, enabling precise reaction temperature management and improved product selectivity.
Hygienic-Grade Construction: Electropolished surfaces with Ra ≤ 0.4 μm meet FDA 21 CFR and EHEDG standards for food, pharmaceutical, and bioprocess applications, ensuring resistance to microbial adhesion and ease of Clean-in-Place (CIP) protocols.
Custom Engineering Capability: Full customization of coil diameter, pitch, tube dimensions, end connections, and material grade to match specific process requirements and vessel geometry constraints.
Long Service Life & Low Maintenance: Austenitic stainless steel construction provides exceptional resistance to corrosion, scaling, and thermal fatigue, ensuring reliable operation for 15–20+ years in continuous service with minimal maintenance intervention.