Stainless Steel DCC Purification Coil Tube for Cleanroom Engineering Systems
1. Product Overview
The Stainless Steel DCC (Direct Cooling Coil) Purification Coil Tube is a precision-engineered heat exchange component manufactured by Wenzhou Jixing Metal Materials Co., Ltd., specifically designed for integration into cleanroom HVAC (Heating, Ventilation, and Air Conditioning) and air purification systems. This coil tube serves as the core thermal exchange element within DCC units, enabling efficient cooling, dehumidification, and air filtration in environments requiring stringent particulate and microbial control, such as pharmaceutical manufacturing facilities, semiconductor fabrication plants, biotechnology laboratories, and hospital operating theatres.
The product is engineered to comply with the rigorous installation standards of clean room engineering, ensuring minimal particulate generation, superior fluid flow dynamics, and long-term structural integrity under continuous operational cycles. The coil tube is supplied in pre-formed coil configurations, facilitating streamlined installation and reducing on-site welding requirements, thereby minimizing contamination risks during assembly.
2. Material & Properties
2.1 Base Material Composition
The coil tube is fabricated from high-purity austenitic stainless steel, primarily SAE 304 (UNS S30400) and SAE 316L (UNS S31603) grades, selected for their exceptional corrosion resistance, hygienic surface characteristics, and compatibility with aggressive chemical cleaning agents used in cleanroom maintenance protocols.
- SAE 304 Grade: Contains a minimum of 18% Chromium (Cr) and 8% Nickel (Ni), providing excellent general corrosion resistance and formability suitable for standard cleanroom environments.
- SAE 316L Grade: Enhanced with a minimum of 2% Molybdenum (Mo) and reduced Carbon (C ≤ 0.03%), offering superior resistance to pitting and crevice corrosion in chloride-rich or high-humidity environments.
2.2 Mechanical Properties
| Property | SAE 304 | SAE 316L | Test Standard |
|---|---|---|---|
| Tensile Strength (Rm) | ≥ 520 MPa | ≥ 485 MPa | ASTM A269 / EN 10217 |
| Yield Strength (Rp0.2) | ≥ 205 MPa | ≥ 170 MPa | ASTM A269 / EN 10217 |
| Elongation (A50) | ≥ 40% | ≥ 40% | ASTM A269 / EN 10217 |
| Hardness (HV) | ≤ 220 | ≤ 220 | ASTM E92 |
| Thermal Conductivity (25°C) | 16.3 W/(m·K) | 16.3 W/(m·K) | ASTM E153 |
| Surface Roughness (Ra) | ≤ 0.5 μm | ≤ 0.5 μm | ASTM B466 / Ra ≤ 0.5 μm |
2.3 Surface Finish Options
- Electropolished (EP): Surface roughness Ra ≤ 0.25 μm, providing a smooth, non-reactive surface ideal for pharmaceutical-grade applications.
- Pickled and Passivated: Standard hygienic finish with Ra ≤ 0.8 μm, suitable for general cleanroom environments.
- BA (Bright Annealed): Ra ≤ 0.4 μm, offering a reflective, low-contamination surface.
3. Technical Specifications
| Parameter | Specification | Notes |
|---|---|---|
| Outer Diameter (OD) | 6.35 mm – 25.4 mm (1/4" – 1") | Custom sizes available upon request |
| Wall Thickness | 0.5 mm – 2.0 mm | Selected based on pressure rating |
| Coil Length | 5 m – 50 m per coil | Custom lengths available |
| Maximum Working Pressure | 1.6 MPa (232 psi) | Tested at 1.5× working pressure |
| Operating Temperature Range | −40°C to +180°C | Continuous operation |
| Fluid Compatibility | Water, Glycol Solutions, Chilled Water, Refrigerant | Non-reactive with common HVAC fluids |
| Welding Process | Orbital TIG (Tungsten Inert Gas) Welding | Back-purged with Argon (Ar) gas |
| Tolerance (OD) | ±0.05 mm | Per ASTM A269 |
| Tolerance (Wall Thickness) | ±10% | Per ASTM A269 |
| Connection Method | Butt Weld, Socket Weld, Flange, Clamp (Tri-Clamp) | Application-dependent |
| Hygienic Standard | EHEDG / 3-A Sanitary Standards | For pharmaceutical and food-grade use |
4. Manufacturing Process
The manufacturing of the DCC Purification Coil Tube follows a tightly controlled, multi-stage production protocol designed to ensure dimensional accuracy, metallurgical integrity, and surface cleanliness at every step:
- Raw Material Procurement: Certified stainless steel strip or seamless tubing is sourced from approved mills with full mill test certificates (MTC) conforming to EN 10204 3.1 or 3.2 documentation requirements.
- Cold Drawing & Forming: The tubing is cold-drawn to achieve precise outer diameter and wall thickness tolerances. Coil tubes are then formed into serpentine or helical configurations using CNC-controlled bending machinery, with bend radii optimized to minimize flow resistance and stress concentration.
- Orbital TIG Welding: All weld joints are produced using automated orbital TIG welding with continuous Argon (Ar) back-purge to prevent internal oxidation. Weld parameters are monitored in real-time to ensure consistent penetration and bead geometry.
- Surface Treatment: Depending on the application grade, tubes undergo pickling (acid bath treatment to remove oxide scale), passivation (chromium enrichment of the surface layer), and/or electropolishing (electrochemical smoothing and passivation).
- Hydrostatic Pressure Testing: Each coil tube assembly is subjected to hydrostatic pressure testing at 1.5× the maximum working pressure for a minimum dwell time of 10 minutes to verify leak-tightness and structural integrity.
- Visual & Dimensional Inspection: Final quality control includes visual inspection for surface defects, dimensional verification using calibrated gauges, and surface roughness measurement using contact profilometers.
5. Applications
The Stainless Steel DCC Purification Coil Tube is specifically engineered for the following critical applications:
- Pharmaceutical Manufacturing: Integration into cleanroom HVAC systems (ISO Class 5–7 / Grade A–C) for precise temperature and humidity control in sterile drug production areas, including cleanrooms, buffer zones, and clean corridors.
- Semiconductor & Electronics Fabrication: Use in ultra-clean environments (ISO Class 1–4) where sub-micron particulate control is essential for wafer processing, photolithography, and etching operations.
- Biotechnology Laboratories: Deployment in HEPA (High Efficiency Particulate Air) filtration systems and laminar flow clean benches for cell culture, tissue engineering, and genetic research facilities.
- Hospital Operating Theatres: Application in positive-pressure surgical suites and intensive care units where airborne contamination control is critical to patient safety.
- Food & Beverage Processing: Utilization in hygienic cooling systems for dairy, beverage, and pharmaceutical-grade ingredient processing lines.
- Electronics Assembly: Integration into controlled-environment chambers for precision assembly of optical components, microelectronics, and aerospace-grade sensors.
6. Quality Certifications & Compliance
The DCC Purification Coil Tube is manufactured under a comprehensive quality management framework that ensures traceability, consistency, and regulatory compliance:
- ISO 9001:2015: Quality Management System certification ensuring consistent production quality and continuous improvement.
- ISO 14001:2015: Environmental Management System certification reflecting sustainable manufacturing practices.
- EN 10217-7: Conformity with European standards for welded stainless steel tubes and hollow sections for pressure purposes.
- ASTM A269: Compliance with American standards for austenitic stainless steel seamless, welded, and heavy-wall tubing.
- EHEDG (European Hygienic Engineering Design Group): Design compliance for hygienic applications in food, beverage, and pharmaceutical industries.
- 3-A Sanitary Standards: Compliance for food and dairy processing applications.
- GMP (Good Manufacturing Practice): Production processes aligned with GMP requirements for pharmaceutical-grade components.
- CE Marking: Conformity with European directives for machinery and pressure equipment (PED 2014/68/EU).
7. Unique Selling Points
Engineered for Cleanroom Excellence: The DCC Purification Coil Tube represents a purpose-built solution for the most demanding cleanroom engineering applications. Key differentiators include:
- Ultra-Low Particulate Emission: Electropolished surfaces with Ra ≤ 0.25 μm minimize particulate shedding, ensuring compliance with ISO 14644-1 Class 5 and below cleanroom classifications.
- Pre-Formed Coil Configuration: Factory-coiled geometry eliminates on-site bending operations, reducing installation time by up to 60% and virtually eliminating the risk of contamination introduced during field fabrication.
- Orbital TIG Weld Integrity: Automated orbital welding with continuous Argon back-purge ensures hermetic, oxidation-free weld joints with superior metallurgical continuity and no internal crevices for microbial harboring.
- Full Traceability: Each coil tube is serialized with material heat numbers, manufacturing batch codes, and test data documentation, enabling complete supply chain traceability in accordance with FDA 21 CFR Part 11 and EU GMP Annex 1 requirements.
- Custom Engineering Capability: Wenzhou Jixing Metal Materials Co., Ltd. offers tailored coil geometry, length, and connection configurations to match specific DCC unit designs and cleanroom layout requirements.
- Extended Service Life: The combination of SAE 316L material, electropolished finish, and passivated surface ensures a service life exceeding 15 years in continuous cleanroom duty, with resistance to CIP (Clean-In-Place) and SIP (Sterilize-In-Place) cycles.
8. Installation Considerations for Cleanroom Engineering
Proper installation of the DCC Purification Coil Tube within cleanroom HVAC systems is critical to maintaining the integrity of the controlled environment. Key installation guidelines include:
- All field connections must be executed using orbital TIG welding or sanitary clamp fittings to avoid gasket-based leakage pathways.
- Installation must be performed under positive-pressure conditions within the cleanroom to prevent particulate ingress during assembly.
- Post-installation, all exposed surfaces must undergo CIP (Clean-In-Place) and SIP (Sterilize-In-Place) validation before commissioning.
- Coil tube supports and hangers must be designed to prevent stress-induced vibration, which could generate micro-fractures and particulate release over time.
- Integration with HEPA/ULPA filtration arrays must account for uniform airflow distribution across the coil face to maximize heat exchange efficiency and prevent dead zones.
Wenzhou Jixing Metal Materials Co., Ltd. provides comprehensive technical documentation, installation guidance, and on-site engineering support to ensure optimal performance of the DCC Purification Coil Tube within any cleanroom HVAC system architecture.