Abstract: The insulative stand-off is mounted on a frame and supports a heating coil. In the preferred embodiment the coil loops engage retention surfaces inside the inverted T-shaped opening in the end of the stand-off. The sides of the stand-off forming the opening have cam surfaces which squeeze adjacent central loops together during mounting while the loops adjacent the central loops are deflected to the outside of the stand-off. When the central loops reach the crossbar of the T they spring apart to fix the coil. Other embodiments are shown--all have retention surfaces generally parallel to the coil loops and transverse the coil axis. Cam surfaces control access to the retention surfaces to deflect the loops as they are moved to the retention surfaces and the coil resiliency biases the loops into engagement with the retention surfaces when mounting is completed.

Abstract: The coiled resistance heating wire is supported on electrical insulating stand-offs in a figure 8 pattern on each side of a metallic radiation panel. The radiation panel and the figure 8 arrangement of the coil each contribute to increased heat transfer to air flowing axially down the assembly in a duct and in combination result in even more efficient heat transfer.