Thick Film Heaters
| Watlow layers thick film resistor and dielectric materials on quartz, stainless steel and ceramic substrates to produce high performance industrial heaters. The thick film heaters provide very fast temperature response and uniformity on a low-profile heater. Thick film heaters are ideal for applications where space is limited, where conventional heaters can’t be used, when heat output needs vary across the surface, or in ultra-clean or aggressive chemical applications. |  |
Applications Guide
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Material
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Typical Watt Densities
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Maximum Operating Temperatures
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W/cm2
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W/in 2
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430 Stainless steel
radiant conduction immersion |
5.0
11.5 27 |
35
75 175 |
550°C (1022°F) 550°C (1022°F) 150°C (302°F) |
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Aluminum oxide
radiant conduction |
3.5 |
23
75 |
550°C (1022°F) 550°C (1022°F) |
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Aluminum nitride
conduction |
23
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150
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300°C (572°F) |
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Quartz
radiant immersion conduction |
3.0
15.4 5.0 |
20
100 30 |
400°C (752°F) 150°C (302°F) 400°C (752°F) |
Applications
- Ultra pure aggressive chemicals
- Large panel processing
- Analytical equipment
- Food service equipment
- Packaging sealing equipment
- Life science sterilizers and GC/mass spectroscopy
- Semiconductor wafer processing equipment
- Plastics hot runner nozzles and manifolds
Thermal Uniformity and Fast Response
| Series 400 Stainless Steel Thick film on stainless steel provides low profile heating with the ability to be laser cut or machined to fit any CAD-generated, two dimensional shape. |
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Watlow’s new thick film heaters on 300 and 400 series stainless steel are ideal for use in many applications where fast response and uniformity are essential. This high-performance heater uses thick film technology to provide maximum temperature response in a compact package. Thick film on stainless steel provides a low-profile heater that has the ability to be laser cut or machined to fit any CAD-generated, two-dimensional shape. Due to the direct surface contact, these thick film heaters ensure greater heat transfer through thermally stable and inexpensive substrates. |
| The heaters can be applied in areas where space is at a premium or where conventional heaters cannot be used because the voltage and wattage combination precludes using other types of resistive heaters. Because of the unique nature of thick film circuit, this heater can be designed to vary heat output across the entire surface. This feature will correct virtually any temperature uniformity problem that current designs may be generating.Watlow’s thick film heaters are manufactured to meet the requirements of NEC codes. UL ® and CSA certifications are pending. | |
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Applications
- Semiconductor: chemical heating, flat panel manufacturing
- Life sciences: thermal cycling, sterilizers
- Aerospace
- Analytical equipment: gas chromatography, spectroscopy
- Constant temperature baths
- Food equipment: steam tables, warewashing, food processing
- Packaging: seal bars, seal rams
- General equipment: fast prototyping
Stability and Fast Response
| Ceramic Ceramic substrates provide low thermal expansion, high temperature tolerance, low dielectric constant, rigidity and dimensional stability for thick film applications. |
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Thick Film on Ceramics Offers Thermal Stability and Fast Response
Watlow’s new thick film heaters are now available using an assortment of ceramic materials as the base substrate. This high performance heater uses thick film technology to provide maximum temperature response in a compact package. Ceramics provide low thermal expansion, a high temperature tolerance, a lower dielectric constant, rigidity and dimensional stability; making it a preferred substrate for many applications. |
| Thick film on ceramic substrates provides a low-profile heater that can be special ordered to fit any CAD-generated, two-dimensional shapes. Due to the direct surface contact, these thick film heaters ensure greater heat transfer through the thermally stable ceramic substrates. The bottom of this page includes a description of each ceramic substrate available for thick film applications.Ceramic substrates are mainly composed of powdered metal oxides or nitrides combined with glass or frit particles. The mix of these materials is varied to generate a range of physical properties. The mixture is shaped into its desired form by either tape casting, powder pressing, roll compacting, or extrusion, and then sintered in to form a hard crystalline structure.
Thick film heaters on ceramics can be applied in areas where space is at a premium or where conventional heaters cannot be used due to the voltage and wattage combination preventing the usage of other types of resistive heaters. Because of the unique nature of thick film circuit, this heater can be designed to vary heat output across the entire surface. This feature will correct virtually any temperature uniformity problems a current design is generating. Watlow’s thick film heaters are manufactured to meet the requirements of NEC codes with UL® and CSA. Certifications are pending. |
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Applications
- Semiconductor: Susceptor plates, integrated circuits
- Life science: Thermal cycling, sample analysis
- Digital printing and laser copying
- Analytical equipment: Gas chromatography and spectroscopy
- Packaging: Seal bars, seal rams
Ceramic Substrates
Alumina (A 2 O 3 ) – Alumina is the most widely used substrate material due to availability, relatively low cost and stable physical properties. This ceramic material is easy to fabricate into a range of shapes while remaining strong at high temperatures and is available in a variety of purity levels.
Aluminum Nitride (AlN) – This material has high thermal conductivity making it an excellent choice where fast response or high levels of uniformity are required. Aluminum nitride is costly to fabricate due to high temperature atmosphere required for firing requirements and material costs.
Beryllium Oxide (BeO) – This material has the highest thermal conductivity available and has excellent dielectric strength needed for some applications. Beryllium oxide is available only in small sizes and safety can be a concern when dealing with toxic beryllium oxide powder.
Silicon Carbide (SiC) – This ceramic is also highly conductive and offers an alternative to aluminum nitride and beryllium oxide. Caution must be used when selecting silicon carbide substrates as dielectric strength can vary as temperature.
In-Line Quartz
| In-line quartz heaters are ideal for use in continuous and intermittent flow aggressive chemical applications. This unique quartz resistive heater module design eliminates process contamination risk in the event of heater failure. | |
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Thick Film In-Line Heaters on Quartz Provide Long Life and Efficient Heat Transfer Watlow’s new, ultra pure in-line thick film on quartz heaters are ideal for use in aggressive chemical applications. This high watt density heater uses thick film technology to provide maximum temperature response and heat output in a compact package.
Watlow’s thick film on quartz heaters deliver an ultra clean heating solution. This |
| unique quartz resistive heater module design eliminates process contamination risk in the event of element failure. With the thick film method, heating elements are fused directly to the exterior surface of the quartz tubes. This provides efficient transfer of heat energy with rapid response to changes in flow and temperature.Life testing has demonstrated significantly longer life than with infrared or other types of conductive heating technologies. The combination of high watt density and compact size makes Watlow’s in-line thick film on quartz heaters perfect for continuous and intermittent flow aggressive chemical applications. | |
Benefits
- Fast response
- Compact size
- High watt density
- Ultra pure quartz
- Long life
- Wattages 1 to 12kW
- 390°F (200°C), maximum operating temperature
- 30 psi, maximum operating pressure
- 35 liters per minute, maximum flow rate
Applications
- Aggressive chemicals
- Ammonium chloride, NH 4 Cl
- Hydrochloric acid, HCl
- Hydrogen peroxide, H 2 O 2
- Isopropyl alcohol, IPA
- Phosphoric acid, H 3 PO 4
- Ultra pure 18 MW deionized water, H 2 O
Corrosion Resistance with a See-Through Option
| Flat Quartz Thick film on quartz substrates provide a low-profile heater that can be cut to fit applications requiring corrosion resistance, high thermal density and visibility. |
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Thick Film on Quartz Offers High Thermal Density and Corrosion Resistance Watlow’s new thick film heaters on quartz glass are ideal for use in many applications where visibility and corrosion resistance are required. This high performance heater uses thick film technology to provide maximum temperature response, and temperature uniformity in a compact package. Thick film on quartz substrates provide a low-profile heater that can be cut or blow molded to fit a variety of shapes and sizes. Since quartz is an efficient radiator of heat, thick film on quartz can be utilized as effective radiant heaters. |
| Thick film heaters can be applied in areas where space is at a premium or where conventional heaters cannot be used because the voltage and wattage combination precludes using other types of resistive heaters. Due to the unique nature of a thick film circuit, these heaters can be designed to vary heat output across the entire surface. This feature will correct virtually any temperature uniformity problem that a current design is generating while still allowing the ability to view the process.Watlow’s thick film heaters are manufactured to meet the requirements of NEC codes with UL® and CSA. Certifications are pending. | |
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FEATURES |
BENEFITS |
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Applications
- Semiconductor: In-line aggressive chemical heating, view ports and vacuum applications
- Life science: Thermal cycling and sterilizers
- Analytical equipment: Gas chromatography and spectroscopy
- General equipment: Fast prototyping
