Thick Film Heating Elements typically consist of a metal plate, coated with a glass-ceramic (enamel). The glass-ceramic is an electrical insulation and carries the printed (conductive) heater tracks. This slim construction provides a robust, low mass, high power density, electric heater. Thick film heating is becoming more and more common as it provides numerous benefits, including energy saving.
Features and Benefits
Low thermal mass combined with high power density.
Accurate Temperature and low overshoot
Rapid response to power adjustments gives close temperature control and low overshoots.
Slim Design and small footprint
Ferro Thick Film Heaters will fit power where other heaters cannot.
Freedom of Design
The heater does not have to be circular. It can be custom, rectangular, horse shoe, oval. Virtually any 2 dimensional shape.
High Energy Efficiency
Low thermal mass = little energy wasted heating the element instead of the target material. Fast rate of rise = no need for standby mode,
Robust and high strength
Robust materials, stainless steel and enamel. EFAST keeps up with the highest power density elements, giving it long term reliability whilst being run to extremes.
Thick Film Element Variations
Direct Heating: Kettle Controls
Ideally the element substrate is in direct contact with the media to be heated.
Here the element has been assembled with Otter’s A12 Kettle Control. The linished stainless steel side of the thick film element forms the base of the kettle, in direct contact with the water. This allows for very high power densities. 3kW on a 110mm diameter disc.
Inline Heating: Liquids / Gases
Thick Film heating can be used to heat liquids and gases as they flow through.
Options are: a tubular printed element; the Ferro Flow Through Heater or aluminium fins brazed to a thick film heater (a fin pack), to assist in transferring the heat into the moving air/gas.
Thick Film Element Construction
The base of a Thick Film element typically consists of a stainless steel substrate. This substrate is then enamelled with a layer of glass-ceramic for electrical insulation. The conductive heater tracks are screen printed on top. Finally a coat of protective enamel is applied, with exposed contact areas for electrical connection.
The element substrate acts as the carrier for the enamel and screen printed layers.
Typically the substrate is stainless steel, however other materials such as ceramic can be used. The substrate can be any two dimensional form. Three dimensional forms which can be screen printed consistently, such as tubes, are possible.
Substrate Insulating Enamel
This insulating enamel layer separates the substrate from the screen printed heating tracks.
This dielectric layer primary purpose is electrical insulation. In addition, it also provides a consistent surface on which to apply the screen printed heating tracks. Sections may be left exposed, or sandblasted away, for attaching items to the substrate.
Thick Film Heating Tracks
The resistive tracks are the most important layer of the element.
By varying the chemical composition and the geometry of the tracks, the element power and heat distribution can be finely controlled. Printed silver contact areas are added for electrical connection. For information on more advanced track design, see the link below.
Element Cover Enamel
The element cover enamel is a protective coat.
Thick Film Technology
While this section provided an overview on the construction of a Thick Film Element, there are far more features. For example EFAST provides instant overheat detection and multi-track designs can give zonal heating or multiple power levels on a single element.
For more details on the technology of Thick Film see our dedicated page below.
Thick Film Element Replacement
Simply switching from a conventional element to a thick film solution improves efficiency by reducing thermal mass.
This will improve the environmental impact of your product, and appeal to the eco conscious market. The more frequently the appliance needs to heat from a cool state the greater the advantage.
You may wish to switch to a Thick Film Heating Element to leverage one of its unique design features.
These features can be used as a point of differentiation in the marketing and feature set of your product. An example of this could be the use of EFAST overheat protection, combined with the elements responsiveness, to more effectively prevent food burning.
Thick Film elements often allow appliances to be significantly smaller.
The elements themselves are smaller than most comparable alternatives and can form a part of the appliance structure. An example of this can be found in thick film kettles, with the element itself becoming the base of the vessel. This opens up the possibility for new & more exotic product design.
Some appliances benefit greatly from a significant redesign to take advantage of thick film.
An example of this is switching from a thermal block to a flow through heater in a coffee machine. This change allows for both hot water and steam to be offered from a single heating system, reducing appliance complexity. Also the ability to rapidly change dispensing temperature allows the option to vary temperature per cup for perfect brewing of different teas. The additional indirect benefits can be great with the right design.