Heating gases
In practice, this mostly concerns heating of air.
Information required to determine the wattage of heating elements for heating gas substances:
- Specification of gas.
- Speed of flow (m/s).
- Density of gas (kg/m3) (in the case of compressed gas).
- Input and target temperature of gas.
- Information about the surroundings (parameters of piping, insulation, etc.).
To design the specific shape of the elements, it is necessary to provide:
- Dimensions of heating area, length of no-heated zones of rods, place for fixing the rods and the space for the terminal box, etc.
- Environment and limiting factors in the place of electric termination (e.g. vibrations, movement of parts, humidity, bending of leads in the place of the leads of the part, risk of mechanical damage or contamination by oil or other liquid, explosive character of the environment, etc.)
- Proposed method of temperature regulation.
- The watt density of rods is stated on the basis of the temperature and the speed of the gas flow.
For more information or help to resolve specific heating issues, please contact us.
You can find the most frequently used elements for heating gases in our catalogue:
Catalogue of elements for heating of gases.
What type of heater do you need?
Tabular heating elements
Due to the price and shape variability, this is the most frequent technology used for heating in furnaces, air ventilation units, heating registers, etc. The maximum recommended working temperature with the suitably proposed watt density of rods (W/cm2) is 750 °C. Versions of rods winded with stainless tape can be used, which increase the area of the passage of the heat into the area and also increases the service life of the rod and the maximum recommended value of the watt density of the rod for specified working conditions.
Flat tubular heating elements
They are mainly used in situations where due to the construction, the leads must be on one side of the rod. The maximum recommended working temperature at a suitably selected watt density of the rod (W/cm2) is 400 °C or 750°C (Use of other insulation Is only possible for rod profiles 9 x 4, 10.5 x 4.5, 13 x 5.5). Versions of rods winded with stainless tape can be used, which increase the area of the passage of the heat into the area and also increases the service life of the rod and the maximum recommended value of the watt density of the rod for specified working conditions.
Heating cartridges
High-performance cartridges – due to the fact that these can be used in conditions that are unsuitable for other heating rod technologies with insulation (high temperature, high watt density W/cm2, small dimensions), they can be used in these extreme conditions. For example, they are fitted into pipes with small dimensions with flowing air. Versions of rods packed with stainless tape can be used, which increase the area of the passage of the heat into the area and also increases the service life of the rod and the maximum recommended value of the watt density of the rod for specified working conditions.
Medium-performance cartridges – values of monitored parameters, i.e. maximum working temperature at the stated watt density (W/cm2 ) are lower than in the case of high-performance heating cartridges. They are also used when long rods (up to 7.5 m) are required or for the termination of leads on one side. Versions of rods winded with stainless tape can be used, which increase the area of the passage of the heat into the area and also increases the service life of the rod and the maximum recommended value of the watt density of the rod for specified working conditions.
Band and nozzle heaters
Band heaters are used in situations when indirect heating is required, e.g. piping with gas, heating of valves, etc., They are not used for direct heating.
Open wire heating elements
These are frequently used in various applications (e.g. high working temperature – up to 1,800°C) as the only possible method for heating gas. For details, see “Open wire heating elements (ceramic, mica)“.
Mica plate heaters
These are both commonly used for heating of air.
Sheath materials:
- AISI 321 – resistance of the tube up to 750 °C
- AISI 304 – resistance of the tube up to 650 °C
- AISI 309 – resistance of the tube (not heating rod ) up to 950°C (dry environment)
- AISI 800 – resistance of the tube (not heating rod ) up to 1050 °C