GENERAL DESCRIPTION
The air duct electric heaters with ATEX certified electric connections head, are heaters commonly used in conditions of limited pressure (less than 0.2 bar) and forced circulation.
They are constituted by heating elements blocks (finned or non-finned) specifically designed and manufactured to offer high performances and at the same time, a high heat exchange.
Outlet Temperature (of the air flow thermally treated ) and surface Density (W/cm ²), in addition to the fluid type and speed (air or gas) in metres per second (m/s), are the variables jointly determining the temperature of the elements installed inside the air duct electric heaters.
In order to grant these products suitability for being installed in dangerous environments subject to explosion hazard, the electric connections are housed and hermetically protected inside one or more electric connections or heads housings for use in explosive environment.
ATEX air duct electric heaters with explosion-proof head are commonly used in low pressure operating conditions (<0.2 bar) and forced circulation. The immersion heating elements installed inside these special heaters are designed and positioned with a specific layout, in order to optimize the heat exchange.
The elements surface temperature depends on the outlet temperature required by the specific application and surface load allowed by the same (W / cm ²), in addition, naturally to the type of fluid to be heated and its speed, measured in metres per second(m/s ) or in kilograms per hour (Kg/h).
The electric connections head is the area under most stress, by the dangerous application, these heaters are subject to. Each air duct electric heater with explosion-proof head can have one or more ATEX certified heads and therefore, suitable for use in explosive environment..
We are able to manufacture explosion-proof air duct electric heaters with ATEX certified head (certified for use in explosive environment Eex-de, Area 1 and 2 – II2G/D ATEX) with CE marking, manufactured in full compliance with the CEI and CENELEC standards in force.
This type of electric heaters is manufactured with high quality materials like carbon steel, stainless steel AISI-304, AISI-321, AISI-316 and Incoloy 800 (heating elements tube) and Galvanized Steel FeZn or Stainless Steel AISI-304/316 (only the frame-structure enclosing the elements and the electric contacts protection head IP65-IP66 and the supply inlets of the power stages and thermalregulation devices (NPT or GAS type).
Typical uses
CERTIFIED QUALITY PRODUCTS
The entire production cycle of explosive-proof air ducts immersed electric heaters is subject to the strictest checks by supervisory bodies, performing severe controls at established frequencies, in full compliance with ATEX regulations.
In addition, this products typology is carefully subject to insulation resistance tests, dielectric rigidity tests, ohmic value and leakage current tests.
TECHNICAL DATA
In product designing this type of products, our technical department makes use of leading computer programs to establish their dimensioning, and of performances thermodynamic calculators, in order to optimize the performances, keeping into consideration the same air duct electric heather operating conditions.
Thanks to the manufacturing experience accumulated during 50 years of activity on the national and international market, in world economy all main industrial sectors, our technical and marketing department always provide the best technical and product design solutions, in addition to the most suitable materials, for the customer’s specific application.
Since the proposal stage, we stand out in comparison with national and international competitors, in supplying all technical details and thermodynamic calculation results, which show the proper air duct heather dimensioning.
PRODUCT DESIGN USEFUL DATA
The manufacturing of an air duct immersion electric heater, consisting both of finned or smooth heating elements, requires the knowledge of some essential technical data for its product design:
| Classe Temp. ATEX / ATEX Temp. Class | ||||||||||||
| ‘T6′: 85°C | ‘T5′: 100°C | ‘T4′: 135°C | ‘T3′: 200°C | ‘T2′: 300 | ‘T1′: 450°C | ||||||||||||
| Lungh. Z.N. / Cold zone Lg. | A | B | A | B | A | B | A | B | A | B | A | B |
| 300 mm | T6 | X | T4 | X | T3 | X | T3 | X | T2 | X | T2 | X |
| 250 mm | T6 | X | T4 | X | T3 | X | T3 | X | T2 | X | T2 | X |
| 200 mm | T6 | X | T4 | X | T3 | X | T3 | X | T2 | X | – | |
| 150 mm | T6 | X | T4 | X | T3 | X | – | – | – | |||
| 100 mm | T6 | X | T4 | X | T3 | X | – | – | – | |||
| 0 mm | T6 | X | – | – | – | – | – | |||||
| Temp. Lavoro / Working Temp. | 0°C | 100°C | 150°C | 200°C | 250°C | 300°C | ||||||
| Legenda:A = Classe Temp. / Temp. ClassB = Ex-proof head Temp.-proof allowance | (X)= Yes | (–)= Not | ||||||||||
CONFIGURATION TYPE
Each heater is equipped with a safety device (upon customer request) limiting the sheath’s temperature in case of heating
elements surface possible overheating, which aims at preventing damages to the heater or to the system where it is installed. Depending on the type of process requested, our technical department suggests the adoption of the most suitable thermalcontrol device (control thermostat, safety thermostat, thermocouple J or K or thermoresistor PT100). It is also possible to equip air Duct electric heater with SCR device or power thyristor to be connected to the control panel and with control systems.
SOME EXAMPLES
