Stainless Steel Coil Tube for Condensation-Free HVAC Systems (Model No. 1154)

Product Overview

The Stainless Steel Coil Tube (盘管 Coil Tube) is a precision-engineered heat exchange component manufactured by Wenzhou Jixing Metal Materials Co., Ltd, specifically designed for integration into condensation-free air conditioning systems. This product has been validated through rigorous experimental research on its comprehensive performance in critical medical environments, including SARS (Severe Acute Respiratory Syndrome) isolation wards. The coil tube serves as the core thermal transfer element in fresh-air ventilation systems, enabling precise temperature and humidity control while eliminating condensate formation—a critical requirement for infection control in healthcare facilities.

Unlike conventional coil tubes that produce surface condensation when the coil surface temperature drops below the dew point of the ambient air, this stainless steel coil tube is engineered to operate above the dew point threshold through optimized thermal design, thereby preventing microbial proliferation associated with stagnant condensate water.

Material & Properties

Primary Material Composition

Key Performance Characteristics

Specifications

Parameter Specification Standard / Reference
Product Code 1154 Internal Catalog
Tube Outer Diameter (OD) 6.35 mm / 9.52 mm / 12.7 mm (1/4" / 3/8" / 1/2") ASME B36.19M
Tube Wall Thickness 0.50 mm – 1.00 mm ASTM A269 / A213
Coil Pitch 10 mm – 25 mm (configurable) Custom / OEM
Coil Diameter 100 mm – 500 mm Custom / OEM
Material Grade AISI 304 / AISI 316L ASTM A240 / A270
Surface Treatment Electro-polished (Ra ≤ 0.4 μm) / Passivated ASTM A967
Maximum Operating Pressure 1.6 MPa (232 psi) ASME B31.9
Design Temperature −40°C to +200°C EN 10217-7
Tolerance on OD ±0.05 mm ISO 1128
Hydrostatic Test Pressure 2.4 MPa (358 psi) for 30 seconds ASME B31.9
Length per Coil 1 m – 50 m (customizable) Custom / OEM
End Form Plain / Beveled / Flanged / Threaded Per Drawing

Manufacturing Process

  1. Material Selection & Inspection: Raw stainless steel strip or seamless tubing is sourced from certified mills (e.g., Outokumpu, Sandvik, POSCO). Incoming material undergoes spectroscopic analysis (PMI) to verify chemical composition compliance with ASTM specifications.
  2. Dimensional Forming: Tubes are cold-formed or hot-rolled to achieve precise outer diameter and wall thickness tolerances. For coil configurations, precision coiling machines wind the tube with controlled pitch and coil diameter.
  3. Welding (if applicable): Orbital TIG (Tungsten Inert Gas) welding is employed for tube-to-header connections, ensuring full-penetration welds with no internal oxide inclusion. Weld parameters are monitored per WPS (Welding Procedure Specification) and qualified per AWS D1.6.
  4. Heat Treatment: Solution annealing at 1050°C–1150°C followed by water quenching to restore full austenitic microstructure and maximum corrosion resistance. Stress-relief annealing at 300°C–400°C may be applied for coil springs requiring dimensional stability.
  5. Surface Finishing: Electro-polishing removes 10–50 μm of surface material, creating a smooth, corrosion-resistant passive layer. Final passivation treatment per ASTM A967 ensures a protective chromium oxide film.
  6. Quality Testing: Each batch undergoes hydrostatic pressure testing, dimensional verification (CMM or laser measurement), surface roughness profiling, and chemical resistance testing (salt spray per ASTM B117).
  7. Final Inspection & Packaging: Coils are inspected for visual defects, marked with traceability identifiers, and packaged in moisture-proof containers to prevent post-manufacturing contamination.

Applications

Primary Applications

System Integration

The coil tube is designed for integration into fresh-air air conditioning systems (新风空调系统) that combine outdoor air introduction with precise thermal regulation. The condensation-free design principle operates on the basis that by maintaining coil surface temperatures above the dew point temperature of the incoming air stream, the system eliminates the need for condensate drainage trays—thereby removing a common vector for Legionella and other pathogenic microorganisms.

Quality Certifications

Unique Selling Points

Validated Performance in Critical Medical Settings: This coil tube product has been experimentally validated through comprehensive performance research in SARS isolation ward air conditioning systems, demonstrating superior condensation-free operation and thermal efficiency under demanding environmental conditions.