Product Overview
The gas-side heat-transfer coefficient is far lower than that of liquids, so the same power needs a larger area—otherwise element surface temperature far exceeds the medium and burns out. Finned tubes add 0.3–0.5 mm steel strip fins outside the sheath by winding or high-frequency welding, with 4–8 mm fin pitch, raising area to 4–8× the bare tube.
Fin material matches the sheath—typically 304, 321, or galvanized steel. For dusty airflow, fin pitch above 8 mm reduces clogging; clean hot air uses 4–5 mm to save space. Fin-to-tube contact quality determines life: wound types need tight root seating, welded types need controlled heat-affected zones.
Elements are usually arranged in a grid within the duct, with face velocity held at 6–10 m/s—too high brings notable pressure drop and noise. Multiple elements are series-connected by high-temperature leads, with terminals in an external junction box to avoid long-term heat aging.
Construction Features
- Wound or HF-welded fins extend area 4 – 8×
- Fin pitch 4 – 8 mm selectable; ≥8 mm recommended for dusty airflow
- Fins same material as sheath to avoid galvanic corrosion
- Suited to duct velocities of 6 – 10 m/s
- Single element 0.5 – 20 kW, grid combinable
- External terminals avoid high-temperature aging
Technical Specifications
| Single Power | 0.5 – 20 kW |
|---|---|
| Rated Voltage | 220V / 380V |
| Tube Diameter | Φ10 / Φ12 / Φ16 mm |
| Fin Height | 8 – 16 mm |
| Fin Pitch | 4 / 5 / 6 / 8 mm |
| Fin Material | 304 / 321 / Galvanized steel |
| Max Temperature | 550°C |
| Air Velocity | 6 – 10 m/s |
The table lists typical configuration ranges. Special pressure, temperature or media conditions require re-checking; final parameters are confirmed by the approved drawings and technical agreement.
Typical Applications
- Air ducts and AHU coils
- Oven recirculation air heating
- Hot-air furnaces
- Paint curing tunnels
- Dehumidification and drying equipment
Information Needed for Selection
- Medium name, concentration, and whether it contains particles
- Total medium volume or circulation flow rate
- Initial and target temperature
- Required heat-up time
- Vessel or pipe size and material
- Supply voltage, phases, and available capacity
- Installation environment and hazardous-area requirements
- Connection standard and mounting orientation
