ALLOWABLE MAXIMUM WATT DENSITY
SELECTION OF OGDEN CARTRIDGE HEATERS
separate listing for Stock Cartridge Heaters.
Heater life is a function of several variables: operating temperature, heater fit, control, heat absorptivity characteristics of material being processed, watt density, contamination, etc.
Immersion Heaters are intended to be used in liquids at all times. The heated portion must always be immersed. Sheath must be free of grease or foreign material for adequate thermal conductivity. Protect terminals from contaminants.
The hole into which a cartridge heater is inserted, should be reamed to the nominal diameter of the heater. Might Watt and Bullet Heaters are .002" - .006" undersized. If close hole tolerances are not maintained, operating life of the heater will be reduced. The heated area of the cartridge should not extend beyond the hole. See watt density graphs.
As a general rule, it is not recommended to space heaters in a die or platen any closer to each other than the diameter of the heater.
Contamination consists of any foreign matter such as plastic, oil, grease, dirt or water entering through the terminal end.
Proper Care and Maintenance
1. Heaters should be stored in a dry area, especially during periods of high humidity.
2. Protect leads from abuse and abrasion.
3. Maintain temperature control and accessories in good working condition to avoid over temperature operating conditions.
4. All cartridge heaters (especially of swaged design) have hygroscopic tendencies and can accumulate moisture in shipping and storage. Low heater insulation (less than 1 meg ohm) can be baked in an oven for several hours or started at low voltage to eliminate moisture.
Removal of heaters from one die to another is not recommended.
Quality control standards on Ogden Cartridge Heaters include the following inspection procedures;
1. Resistance test.
2. Voltage breakdown test (Hypot)
3. Inspection of physical size.