Stainless Steel Dry Coil Tube for FFU Clean Air Conditioning Systems
Product Overview
The stainless steel dry coil tube (Coil Tube) is a precision-engineered refrigeration component designed specifically for Fan Filter Unit (FFU) clean air conditioning systems deployed in high-purity electronics manufacturing environments. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd, this product is engineered to meet the stringent requirements of semiconductor fabrication, photolithography, and microelectronics assembly facilities where ultra-low particulate contamination and precise thermal regulation are critical.
Unlike conventional wet coil systems, the dry coil tube operates as a non-condensing heat exchanger that provides sensible cooling without introducing moisture into the airstream. This eliminates the risk of condensate formation, which is unacceptable in Class 1 to Class 10,000 cleanrooms governed by ISO 14644 standards. The coil tube serves as the primary heat transfer medium within the FFU unit's air handling circuit, ensuring uniform temperature distribution across the cleanroom floor.
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, selected for its superior corrosion resistance, thermal conductivity, and mechanical durability under continuous cycling conditions.
- Base Material: Stainless Steel Grade 304 (UNS S30400) / Grade 316L (UNS S31603) — the latter providing enhanced resistance to chloride-induced pitting in coastal or chemically aggressive environments
- Chromium (Cr) Content: 18–20%, ensuring robust passive oxide layer formation and long-term corrosion immunity
- Nickel (Ni) Content: 8–10%, providing austenitic stability and ductility for precision forming
- Molybdenum (Mo) Content: Up to 2.5% (Grade 316L), enhancing resistance to localized corrosion
- Surface Finish: Electropolished or passivated to achieve a surface roughness (Ra) of ≤ 0.4 μm, minimizing particulate generation and facilitating chemical cleaning
- Operating Temperature Range: −40 °C to +150 °C, accommodating extreme thermal cycling without material degradation
- Maximum Working Pressure: Up to 1.6 MPa (232 psi), with pressure-tested integrity at 1.5× design pressure
- Thermal Conductivity: 16 W/(m·K) at 20 °C, providing efficient heat transfer performance
Specifications
| Parameter | Specification |
|---|---|
| Product Category | Dry Coil Tube (Coil Tube) for FFU Clean Air Systems |
| Material Grade | SUS304 / SUS316L / Custom Alloy |
| Outer Diameter (OD) | 6.35 mm / 9.53 mm / 12.70 mm (1/4" / 3/8" / 1/2") — customizable |
| Wall Thickness | 0.5 mm – 1.5 mm (adjustable per thermal load requirements) |
| Coil Pitch (Spacing) | 3.0 mm – 12.0 mm (configurable for airflow resistance optimization) |
| Tube Length (Per Coil) | 15 m – 60 m (continuous coil configuration) |
| Refrigerant Compatibility | R-134a, R-410A, R-407C, R-32, Water/Glycol Solutions |
| Surface Treatment | Electropolishing / Passivation / PTFE Coating (optional) |
| Connection Type | Flared, Brazed, Soldered, or Quick-Connect Fittings |
| Compliance Standards | ASME B31.5, EN 10217, JIS G3459, ISO 14644 |
| Minimum Order Quantity (MOQ) | Negotiable based on specification |
| Customization | Full OEM/ODM support — dimensions, coil geometry, and finish tailored to project |
Manufacturing Process
The production of the dry coil tube follows a rigorous, multi-stage manufacturing protocol to ensure dimensional accuracy, metallurgical integrity, and surface quality consistent with cleanroom-grade requirements.
- Material Selection & Incoming Inspection: Virgin stainless steel coils are sourced from certified mills. Each batch undergoes spectroscopic analysis (OES — Optical Emission Spectroscopy) to verify chemical composition and mechanical property certification per ASTM A240 / ASTM A269.
- Blank Cutting & Forming: Precision slitting machines cut the coil stock to specified width and thickness tolerances (±0.05 mm). The flat stock is then fed into high-precision roll-forming dies to create the seamless tubular profile.
- Seam Welding: Where applicable, the tube seam is formed using TIG (Tungsten Inert Gas) welding or laser welding under argon shielding atmosphere, producing a fully fused, leak-tight joint with minimal heat-affected zone (HAZ).
- Coil Winding: The formed tube is wound into the designated spiral geometry using CNC-controlled winding equipment, maintaining constant pitch and concentricity tolerances of ±0.2 mm.
- Heat Treatment & Stress Relief: The assembled coil undergoes solution annealing at 1050 °C – 1150 °C followed by controlled water quenching to restore full austenitic microstructure and eliminate residual stresses from forming operations.
- Surface Finishing: Electropolishing removes the outer 2–5 μm layer of metal, producing a smooth, passivated surface with Ra ≤ 0.4 μm. This step is critical for minimizing particulate shedding in cleanroom applications.
- Pressure Testing & Leak Detection: Each coil tube is hydrostatically tested at 1.5× the maximum working pressure for a minimum dwell time of 30 minutes. Helium mass spectrometer leak testing (detection limit: 1×10⁻⁹ mbar·L/s) is performed on critical applications.
- Final Inspection & Packaging: Dimensional verification via coordinate measuring machine (CMM), visual inspection under magnification, and documentation compilation. Tubes are packaged in moisture-barrier protective wrapping with desiccant packs for shipment.
Applications
The dry coil tube finds primary application in the following high-precision environments:
- Semiconductor Fabrication Facilities: Integration into FFU-based laminar airflow systems for wafer fabrication cleanrooms (ISO Class 1–5), where moisture-free cooling is mandatory to prevent contamination of photoresist-coated wafers.
- Photolithography & Etching Bays: Temperature-stabilized air delivery for optical lithography equipment and plasma etching chambers requiring ±0.1 °C thermal uniformity.
- Flat Panel Display (FPD) Manufacturing: Cleanroom HVAC systems for TFT-LCD, OLED, and AMOLED production lines requiring particle counts below 3,520 particles/m³ (ISO Class 5).
- Biotechnology & Pharmaceutical Cleanrooms: Controlled-environment cooling for GMP-compliant facilities where condensation-free operation prevents microbial growth and product contamination.
- Data Center Precision Cooling: High-density server room cooling systems utilizing dry-cooling principles to maintain equipment within optimal thermal envelopes without humidity-related electrical hazards.
- Aerospace Component Assembly: Ultra-clean assembly environments for avionics, satellite, and spacecraft component integration where particulate and moisture control are mission-critical.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management infrastructure to ensure product conformity with international standards:
- ISO 9001:2015 — Quality Management System certification ensuring consistent production quality and continuous improvement processes
- ISO 14001:2015 — Environmental Management System certification for sustainable manufacturing practices
- ISO 14644-1 — Cleanroom classification compliance, with manufacturing facilities maintaining ISO Class 7 or better for final assembly and testing
- ASME B31.5 — Compliance with pressure piping and plumbing components standards
- EN 10217 — European standard for welded stainless steel tubes for mechanical and structural purposes
- CE Marking — European Conformity certification for products entering the European Economic Area
- RoHS 2.0 Compliance — Restriction of Hazardous Substances directive adherence for electronics industry supply chain integration
- Mill Test Reports (MTR) — Full chemical and mechanical property documentation provided with each shipment, traceable to the heat number of the raw material
Unique Selling Points
The dry coil tube from Wenzhou Jixing Metal Materials Co., Ltd differentiates itself in the competitive FFU clean air conditioning market through several key technical advantages:
- Zero-Condensation Design: Engineered specifically as a dry coil, eliminating all risk of moisture ingress into ultra-clean environments — a critical differentiator over conventional evaporative coil systems.
- Ultra-Low Particulate Emission: Electropolished surfaces with Ra ≤ 0.4 μm reduce particulate shedding to negligible levels, maintaining ISO Class 1 cleanroom integrity over extended operational lifetimes.
- Full Customization Capability: OEM/ODM manufacturing supports project-specific coil geometries, tube dimensions, and connection configurations, enabling seamless integration into proprietary FFU architectures.
- Extended Service Life: Superior corrosion resistance of 316L grade stainless steel provides operational lifetimes exceeding 15 years in aggressive chemical environments, minimizing maintenance downtime in continuous-production facilities.
- Traceable Quality Documentation: Complete lot-by-lot traceability from mill certificate through final inspection ensures compliance with semiconductor industry qualification requirements (e.g., SEMI S2, SEMI S8).
- Thermal Performance Optimization: Precision coil pitch control and wall thickness engineering maximize heat transfer coefficient (U-value) while maintaining low pressure drop across the coil, reducing fan energy consumption by up to 20% compared to standard designs.