Constructed of sturdy 0.430 in. (11 mm) diameter Watlow's WATROD™ heating elements mounted to a 1/4 in. (6 mm) thick steel flange, duct heaters are easily adapted to many non-pressurized air-heating systems. They are easily installed in applications requiring a wide range of temperature versus air flow combinations. The modular duct heater offers increased reliability. The individual modules are removable through the housing of the assembly, which eliminates the need to pull the complete heater from the duct work. This reduces downtime costs because the heating elements can be replaced individually. Performance improvements include quicker response time and reduced infiltration from the air stream being heated into the electrical enclosure. Duct heaters offer advantages over gas or oil fired and open coil electric units with:
- Installation flexibility—no flues or fuel lines
- 100 percent energy efficient—no energy loss up the flue
- Universal availability of electricity
- Resistance coil in sheath is protected from corrosive environments
- Watt densities to 40 W/in2 (6.2 W/cm2)
- Recommended process temperatures from -20 to 1200°F (-29 to 650°C)
- Catalog P/N wattages to 225kW
- Voltages to 600VAC
Features and Benefits
- Long life alloy 800 sheath resists corrosion/oxidation while protecting resistance coils against contamination
- MgO insulation filled elements compacted to rock hard density maximizes dielectric strength, heat transfer and life
- Field replaceable heating elements permits easy service and reduces downtime
- General purpose terminal enclosure offers easy access to wiring
- WATROD hairpins are recompacted after bending to eliminate hot spots and electrical insulation voids
- Drying ovens
- Load banks
- Heat treating
- Paint drying
- Moisture and Explosion Resistant Terminal Enclosures and High temperature stand-off enclosures
- Alloy 800 and 840, Laminated alloy 600 (high-temp), Hastelloy® C276, 304, 316 and 321 stainless steel sheath materials
- Type J or K thermocouples, inserted in the thermowell, to accurately sense element sheath temperature for over-temperature conditions.
Download the Duct Heater Datasheet
Modular Duct Heaters
Modular duct heaters offer improved performance and increased versatility in medium to low temperature applications and consists of two parts. The first is a 6 kilowatt heater available in either 240 or 480 volts, single- or three-phase. The second part of the heater consists of the electrical housing protecting each module’s termination area and a main flange that bolts into the user’s ductwork. The heater modules are installed in the housing and main flange via rectangular slots in the main flange. The range of modules that can be accommodated in various duct heater assemblies range from one to 10 modules. A range of 6 to 60 kilowatts, in 6 kilowatt increments is achieved.
The design of the modular duct heater offers increased reliability. The individual modules are removable through the housing of the assembly, which eliminates the need to pull the complete heater from the ductwork. This reduces downtime and costs because the heating elements can be replaced individually.
Performance improvements include quicker response time and reduced infiltration from the air stream being heated into the electrical enclosure.
Features and Benefits
- Individual modules are removable through housing reduces downtime for replacement of the module
- Smaller diameter elements (0.315 inch) results in a 25 percent lower energy usage on the initial heat-up
- 27 percent reduction in heat-up time as compared to traditional 0.430 inch diameter duct heater elements results in a faster response time
- 31 percent lighter weight than traditional tubular duct heaters reduces shipping costs and increases worker safety
- Greater free cross sectional area results in lower pressure drop
- Improved seal between the element and electrical housing results in lower electrical housing temperature
- Flexible module wiring allows user to sequentially stage modules
- Low temperature ovens
- Parts drying
- Semiconductor clean room environmental heating
- Plastic curing
- Load banks
- Heated air knives
- Food dehydration
- Heat shrink tunnels
- Terminal Enclosures are available in general purpose and moisture resistant configurations.
- High-Limit Thermocouples can be supplied on specified modules or shipped as a kit. Available thermocouples are Types J and K.
- Blank Module Covers are available for covering blank slots on the main flange. This allows for adding heater modules at a later time to allow higher wattage outputs.
Download Modular Duct Heater Datasheet
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