Electrical heating cartridges can be produced for a variety of diameters. The following list shows the most frequent diameters; in addition, many intermediate dimensions are available.
I. Metric dimensions
- 4 mm
- 6,5 mm
- 8 mm
- 10 mm
- 12,5 mm
- 16 mm
- 20 mm
- 25 mm
- 32 mm
II. Imperial dimensions
- 1/4" (6,35 mm)
- 3/8" (9,53 mm)
- 1/2" (12,7 mm)
- 3/4" (19,05 mm)
- 1" (25,4 mm)
Today, electrical heating cartridges are mainly made of corrosion-resistant stainless steel. Due to the past, heating cartridges with a brass sheath can still be found. The disadvantage of brass is a worse resistance against chlorine (e.g. for the processing of PVC); the lower prospensity to corrosion is an advantage over stainless steel.
Materials for the heating cartridge sheath:
- Corrosion-resistant stainless steel
- Brass
- Heat-resistant stainless steel
If the heating cartridge is not used for heating a workpiece but for liquids, this can be taken into account during the selection of materials in many cases.
Available materials of the heating surface:
- Carbon steel
- Corrosion-resistant stainless steel
- Heat-resistant stainless steel
- Titanium, Hastelloy, special materials
- Copper-nickel
Electrical heating cartridges are mainly distinguished by compacted and non-compacted designs. The higher the loads caused by temperature, but also in case of vibrations etc., the more a compact design will be used. In case of so-called high-capacity heating cartridges the heating coil is as close as possible to the bottom side of the surface for obtaining a uniform temperature distribution and a high load capacity.
I. Heating element design
- Normal cartridge: Sheath of brass, steel or stainless steel, surface load up to 6 W/cm², price-efficient
- Compacted heating cartridge: Sheath of stainless steel, surface loads of up to 12 W/cm² possible
- High-capacity heating cartridge: Sheath of stainless steel, surface loads above12 W/cm² possible
Wherever heating is required, control is also necessary in almost all cases. We are of course prepared to deliver the corresponding controller for your heating cartridges. There are different variants of control which can be selected according to the desired quality.
I. Controllers
- Electronic ON-OFF control or PID control. (-> ON-OFF control switches off the heater if the temperature is exceeded, and switches it on again when the temperature falls below its lowest value. Thus, the temperature will always oscillate around the setpoint. The algorithm of the PID controller will optimally compensate the control fluctuations.)
- Load switching by contactors or wear-free semiconductors (thyristors). (-> contactors are wearing parts and must be replaced after approx. 100,000 make/break operations; thyristors switch quickly and without any wear but generate more heat losses than contactors.)
- Electromechanical control. Thermostats installed on the tool are price-efficient controllers whose accuracy is sufficient for many applications.
II. Sensors
- Thermal protectors and limiters as capillary thermostats (as a safety design as well).
- Temperature sensors for tool or heating cartridge temperatures
A variety of designs is available for electrical heating cartridges. We are prepared to agree with you on the variant suitable for your application, considering factors such as temperature, mechanical load and environmental influences.
I. Electrical connections
- Glass-silk-insulated nickel wire for temperature of up to 250°C
- Teflon-insulated nickel wire for temperatures of up to 220°C and moisture-proof design
- Feeder protection of a glass-silk hollow tube, metal mesh or corrugated metal hose, gas-tight available as well.
II. Mechanical designs
- Fastening strip
- Knockout spigot
- Fastening flange
- Screw-in thread, metric or Imperial
- Angle block or pipe bend
The heating cartridges can be produced in lengths from approx.. 30 mm up to 3000 mm. Subsequent shortening of a heating cartridge is unfortunately not possible. Therefore, the heating cartridge must be produced to its proper length.
Different heating zones (with different surface loads) can be implemented for the heated length. Depending on the diameter of the heating cartridge, these heating zones can also be selected individually. Thus, an exact temperature control is possible over the length of the heating cartridge.
