MHI GAXP® Heating Element Worksheet for Furnace Design
High Radiative Power With GAXP®
Steps for calculating the total length of MHI GAXP® heating elements for a new furnace.
Step 1. Power Required.
Please size the furnace interior. Now use the furnace calculator on GAXP® to determine how much power is required for the furnace at the maximum temperature..
Step 2. Additional Power Required?
Make further power corrections if the planned furnace insulation is weak or a high heat -up rate is required. Adding about 50% more than calculated power in Step 1 may be ideal if the insulation is weak.
Step 3. Determine the Shape and Size of Individual Heating Element
(Choose the shape, size it to your furnace, and use this calculator for checking power per element and total power from all elements).
Please read adjacent Panel which will help you choose between U Shaped, Dumbbell shaped and MagnaCoils™. If U-shaped, choose a Le of about 0.25 inches less than the inside furnace height. U-shaped elements are hung from the furnace-roof or from the furnace sides. Dumbbell elements are used in a horizontal position inside a furnace. Schematics of various configurations inside a box furnace are shown below under step 5 in 'More Resources'. Calculate the total GAXP® element heater length required by choosing a shape, sizing it to your furnace, and using the calculator for calculating power delivered by each heating element. The calculator will also show the total power for the number of heating elements considered. Please ensure that the total power is at least equal to the Step 2 result.
Step 4. Electrical Connectors.
For electrical connectors please visit GAXP Element Connectors - U or Dumbbell Shape (or use Accessory Pack #3 for MagnaCoil™ heating elements). Prices of connectors are also shown for each accessory pack..
Step 5. Tips.
The cold (terminal) section, Lu, should be at least a few inches larger than the insulation in order to connect your electric (braided wires) properly. Connections must not get hot during use. Good furnace manufacturers use strong fans to keep the terminal area (electrical connections region) in a cold state.
Step 6. Consult Resources.
Contact MHI for a final check. MHI can provide advise on the control system you may need (BPAN, XPAN or TRIPAN). BPAN prices are listed in the MHI store. When purchasing a control panel please ensure features like soft start and current limits. Please use a power transformer that matches the voltage of the furnace. MHI can also provide a certification-logo for the furnace.
More Resources and Tips
How to determine my best heating element material for the highest productivity. Should a GAXP® class or a MP class heater materials be chosen? Contact MHI for additional information. For temperature higher than what GAXP® furnaces can offer please visit Molysilicide Heating Elements and also view Economics Pages.
Picture shows a schematic of the use of U-shaped, dumbbell-shaped and flat coil-shape heating elements inside a box-furnace interior
Use GAXP® elements
- Nanostructured element. Patented material from a well-respected supplier in business for twenty years.
- Typical shapes: Hairpin shape (same as U-shaped), Dumbbell (same as straight) or Coil. (See schematics pictured below).
- For use in air (oxidation) carbon (reducing), neutral or combustion atmosphere. (The GAXP® is a patent protected technology product).
Sample Heater Shapes
For temperatures < 1000°C use of the Dumbbell shape is allowed. For tempeartures over 1000°C use U shaped. For coils contact MHI for assistance. Coils may be used for any temperature.
*Furnaces should be constructed only by experienced furnace maker. Please observer all safety rules/practices commonly associated with high temperature, high voltage, high current. Always please use only industry approved insulation. Please use high temperature safety glasses, respirators and safety gloves that are rated for high temperature and high voltage.