Indeeco - Explosion-Proof Duct Heaters
Ultra-Safe™
Explosion-Proof Duct Heaters
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Engineering developments at Indeeco have made explosion-proof duct heaters for hazardous locations readily available at affordable prices.
- CSA-approved for virtually all Class I and Class II, Division 1 and 2 hazardous gas or dusty atmospheres
- Ignition temperatures as low as 320 °F (160 °C)
- Six standard sizes to fit a wide range of ducts
- Ratings up to 240 kW, 600 volts
Standard Construction
- Heat Exchanger: copper tubes with integral aluminum fins. Each unit undergoes hydrostatic testing at 350 psig, five times the pressure relief valve setting of 70 psig.
- Heat Transfer Fluid: propylene glycol, a nontoxic, rust-inhibiting fluid that provides freeze protection to -49 °F (-45 °C). Its high heat transfer rate at 70 psig makes the heat exchanger suitable for gases that ignite at temperatures as low as 320 °F (160 °C). Thus every Ultra-Safe heater is rated for Temperature Code T3C.
- Industrial Grade Heating Elements: built by Indeeco, .475″ (1.21 cm) diameter to provide extra insulation between the coil and sheath for high voltage protection.
- Frame: heavy gauge galvanized steel, fitted with lifting lugs to facilitate installation.
- Four Levels of Safety: Every heater has automatic and manual reset thermal cutouts, airflow interlock, and pressure relief valve. Two thermal cutouts limit the heat transfer fluid temperature. The automatic reset operates a “primary” magnetic contactor, and the manual reset uses a separate backup magnetic contactor. If either cutout opens, the entire heater is de-energized. A fan relay, acting as an airflow interlock, prevents the heater from being energized unless the fan starter is on. The pressure relief valve on the heat exchanger opens only if the thermal cutout system fails to prevent excessive temperatures.
Standard Built-in Control Package
The following components are mounted in a cast aluminum explosion-proof enclosure:
- De-energizing control and backup magnetic contactors
- 24V control circuit transformer
- Fan relay, supplied with 24V or 120V holding coil to match the fan starter coil voltage
- Terminal blocks for field power and control wiring
- Grounding terminal
- Supplemental fusing for heaters drawing more than 48 amps
Series EP
Explosion-Proof Duct Heaters
For More Information:
Engineering developments at Indeeco have made electric duct heaters for hazardous locations readily available at affordable prices.
- CSA Approved for Class I, Division 2 locations where a hazardous gas is occasionally present
- Ignition temperatures as low as 392 °F (200 °C)
- For ducts up to 240″ (610 cm) wide by 120″ (305 cm) tall
- Ratings up to 1000 kW, 600 volts
Standard Construction
- Galvanized Sheet Metal Frame: includes external flanges for field mounting and an element terminal box. Terminals are factory-connected to control safety components in an integral cast aluminum explosion-proof box.
- Three Levels of Safety: Every heater includes automatic and manual reset thermal cutouts, plus a fan interlock relay. The automatic reset cutout, operating through the temperature control system, is the primary protector. The manual reset operates a separate backup magnetic contactor independent of the temperature control system. The fan interlock relay prevents the heater from being energized unless the fan starter is on.
- Industrial Grade Heating Elements: built by Indeeco, are .475″ (1.21 cm) in diameter to provide extra insulation between the coil and sheath for high voltage protection. Stainless steel fins are helically wound onto the stainless steel sheath.
Standard Built-in Control Package
The following components are mounted in a cast aluminum explosion-proof enclosure:
- De-energizing control and backup magnetic contactors
- 24-volt control circuit transformer
- Fan relay for heater/fan airflow interlock. Supplied with 120V or 24V coil to match the fan starter
- Terminal blocks for field power and control wiring
- Grounding terminal
- Supplemental fusing for heaters drawing more than 48 amps
Custom
Explosion-Proof Duct Heaters
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Indeeco generally constructs heaters per Series EP2, except with element terminals and control components built into a cast aluminum explosion-proof enclosure.
Standard Construction:
- Frame: sized to fit the duct. Slip-in is also available, if necessary, to match other equipment. Galvanized steel standard; stainless steel optional.
- Control Enclosure: NEMA 7, 9 cast aluminum box with hinged cover houses controls and element terminals. Weatherproof construction is optional.
- Heating Elements: heavy wall, large diameter stainless steel finned tubular elements, individually removable for servicing.
- SCR Temperature Control: SCRs with zero-cross firing provide precise proportional control. SCRs also minimize element operating temperatures for extra safety. Optional on/off single or multi-stage control is also available.
- Overtemperature Protection: Thermocouple controllers measure element sheath temperature. Automatic reset control resets when the temperature drops to a safe level. Manual reset control, with an external button, provides backup protection.
- Fuses: individual circuit fusing for heaters drawing over 48 amps to meet NEC requirements.
- Airflow Interlock: The fan relay prevents heater operation unless the fan becomes energized. Built-in or remote explosion-proof airflow switch is optional.