



Cartridge heaters can be considered "component heaters" that are used to heat up many different applications. Primarily used in mould, these heaters fit snug inside a cavity and helps heat solids by reaching high tempeartures. Cartridge heaters have the veratility of being able to carry thermocouple inside to help control temperatures of the ehater more accurately. Various diameters allow for it to be used in any cavity and can be custom designed with any cold section. Lead wires exptend from the end to your controls. Cartridge heaters are used in bag sealing applications, hydraulic oil applications, motor oil applications, gear boxes, water based applcations as well as laboratory and food equipment. Sheaths can reach extreme temperatures as cartridge heaters can be designed with higher watt densities. High watt density cartridge heaters also have the ability of having different types of lead wire connections. For more mechanical processes, stainless steel braided leads are used against mechanical stress. BX cabling can be used for added protection however it reduces the lead wire flexibility. Terminal pins are also available on all models. Cartridge heaters from Wattco are made of a swaged construction that consists in a high-grade nickel chromium resistance wire wound around a high-quality MgO core that is centered in a stainless steel casing.
Cartridge heaters are used for heating metal parts and can also be fitted with threaded bushings for liquid heating for certain applications. Cartridge heaters will reach metal temperatures of up to 1,400ºF (760ºC) with the appropriate material, watt density, and fit selections (see Figure 2 on our catalog page 7.2).



Built-in thermocouples
One optional feature on WATTCO cartridges is built-in thermocouples. These could be type "J" or "K", grounded or ungrounded, and attached either at the disc end or the middle of the cartridge.

Graphite coating
To facilitate their installation and removal, cartridges could be coated with a graphite-like
substance. This solid lubricant doesn't increase the outside diameter, and is suitable for temperatures
up to 750° F

Moisture and contamination proofing
To protect cartridge heaters against moisture and contamination, Teflon lead wires are
used and the lead end is sealed using Epoxy, RTV silicone or Teflon. The temperature limitation
is 480° F

Distributed wattage
In applications such as sealing bars or rubber molds, the two ends of a cartridge heater are usually colder than the middle. To overcome this inconsistency and have a uniformly distributed heat source, cartridges could be made to have higher wattages at the ends. 35/30/35 is a common wattage distribution.

Center-less grinding
In applications where superior heat transfer is required, the tolerance on the outside diameter could be improved to +/-0.001" by center-less grinding.

Zones and cold sections
WATTCO can also manufacture cartridges with cold sections and separate zones that can be controlled independently.



| Specification | Description |
|---|---|
| Resistance wire | High grade nickel chromium resistance wire |
| Core | MgO core |
| Casing | Stainless steel |
| Leads | Stranded leads with silicone impregnated mica glass insulation |
