| 摘要 |
A heater is provided that includes a resistance coil assembly defining a first end portion having a first conducting pin and a second end portion having a second conducting pin, and a resistance coil disposed between the first end portion and the second end portion, the resistance coil defining a plurality of different pitches between the first end portion and the second end portion. An insulating material surrounds the resistance coil assembly, and a sheath surrounds the insulating material. The plurality of different pitches provide a variable watt density such that a predetermined temperature profile is provided along the sheath.
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