FIREROD CARTRIDGE HEATERS ® PROVIDE QUALITY AND ENGINEERING EXPERTISE FOR YOUR MOST DEMANDING APPLICATIONS

FOUR QUESTIONS TO ASK WHEN SELECTING YOUR CARTRIDGE HEATER SUPPLIER 1. Does my cartridge heater supplier provide a complete product and service package? 2. Can I be sure I’ll get the products I need, when I need them? 3. Is my cartridge heater supplier building the best product possible? 4. Does my cartridge heater supplier provide application assistance to solve my heating problems? Selecting cartridge heaters for industrial applications should involve more than just specifying temperature and power requirements. Today’s users benefit when their cartridge heater supplier can provide: Custom...

1. Does my cartridge heater supplier provide a complete product and service package? Watlow does. • Watlow is the only designer and manufacturer to offer single source thermal system capability with our complete line of heaters, sensors and controllers. You are assured of Watlow quality in each system component. • Continuous product testing is one way we ensure quality at Watlow. Our commitment to Total Quality and World-Class Manufacturing programs also leads to continual product improvements for the FIREROD heater. • Prototype testing is often performed for special customer applications, such...

3. Is my cartridge heater supplier building the best product possible? Watlow is. FIREROD cartridge heaters from Watlow are built using only the finest materials and construction methods, and are backed with extensive quality assurance programs. The FIREROD’s advantages: PREMIUM MATERIALS Watlow refuses to take shortcuts. Years of testing have proven certain construction materials and manufacturing methods to yield the best performance for FIREROD cartridge heaters. Following are the standard materials we use. • The Sheath: Our standard Incoloy® 800 provides high temperature resistance to oxidation...

CONSISTENT QUALITY STANDARDS Instead of adapting our manufacturing processes to the equipment available, Watlow designs and builds its own manufacturing machinery. As with our customized swaging equipment, this allows more consistent quality and tighter tolerances. It also gives us more freedom when modifying or developing products. We developed our own MgO fill density equipment, calibrated to our exact needs and designed so that humidity, temperature or other factory conditions will have no effect on the MgO. Watlow’s fill machines are designed to ensure uniform fill thickness which results...

CONTAMINATION CONTAMINATION Table 1 Seal Type Maximum Continuous Operating Temperature 5. 1. Overtemperature: The discolored portion indicates part of the heater was operated in open air, rather than being fully inserted in the application. 2. Overtemperature: Resulted in breakdown of insulation, and caused element to short to ground and burn a hole in the sheath. 3. Contamination: External view. Molten plastic has solidified on the heater and the leads. 4. Contamination: Internal view. Notice that more reaction has occurred in the element winding area, where temperatures are highest. 5. Overtemperature...

FIREROD heaters can be designed with special seals to resist contaminants. Watlow offers several seal types to handle various application temperatures. (See Table 1). It is important to realize that the seal or lead end of the heater will not exceed the maximum operating temperature of the seal material. This can be accomplished in one of two ways. One way is to allow enough natural or forced air convection to cool the area. In other cases, it may be necessary to specify a length of no-heat zone between the heated and the sealed areas of the heater. Smaller diameter heaters drop in temperature...

. Color . Versus . . Temperature . . . . The chart was created by recreating the colors of Incoloy® sheathed FIRERODs at specific temperatures. Several factors may affect the color, but the chart is a handy reference of color vs. temperature for most metal objects. The power levels indicated were calculated using the Stefan-Boltzman equation for a blackbody source at the temperatures listed. NOTE: Maximum part temperature 760°C (1400°F), maximum watt density 69 W/cm2 (400 W/in2). OVERTEMPERATURE OF THE HEATER Graph B: How Hole Fit & Watt Density Can Affect Internal Heater Temperature Heater Operating...

SENSOR LOCATION Poor temperature sensor location is another common cause of overtemperature heater failure. If the controlling thermocouple is placed on the edge of a heated part that runs cooler due to “end effects” of heat losses to atmosphere, the center portions of the heated part can run significantly higher in temperature, forcing the heater to operate well over its maximum recommended temperature. The solution is to place the temperature sensor in the hottest part of the application. When heating fluids or gases in chambers, the process becomes hotter as it flows through the chamber. Thermocouples...

WATLOW SOLUTIONS TO YOUR HEATING PROBLEMS Watlow specializes in solving demanding heater applications through customized engineering. Our experience is reflected in our design of over 250,000 different FIREROD heaters for such industries as plastics processing, packaging, medical equipment, aerospace, scientific instruments, semiconductor, foodservice and nuclear power generation. SOLUTION TO COMPLEX HEATING PROBLEM CONTAMINATION PROBLEM A gas analysis system required a heat source capable of handling temperatures above 649°C (1200°F) and to provide heat to the analyzer head from distances of...

An additional problem with the application involved the high throughput required for the machine, making the duration of heater contact less than one second. A FIREROD heater was designed with a centerless ground sheath for good hole fit and heat transfer, and a special fill material in the heater to greatly increase the heater’s thermal conductivity. Watlow conducted testing to determine the proper heat zoning needed to compensate for heat losses at the ends and at the machinery clamps. A FIREROD cartridge heater with special distributed wattage was designed, providing the extremely tight profiles...