Staple for holding heating element in place

A heating unit comprising:

• a pan having a generally flat base and a circumferential sidewall;
• a first insulation layer having an insulation base and a circumferential sidewall;
• a second insulation layer positioned between the insulation base of the first insulation layer and the flat base of the pan;
• a heating element supported on the insulation base of the first insulation layer;
• a plurality of staples to retain the heating element on the insulation base of the first insulation layer, the staples extending through the insulation base of the first insulation layer.

A staple for a heating unit, the heating unit having an insulation layer and a heating element, the insulation layer having a top surface, the heating element resting on the top surface of the insulation layer, staple comprising:

• a base capable of straddling a portion of the heating element;
• a leg extending from the base;
• and
• a barb attached to the leg;
• wherein the barb and a portion of the leg are capable of extending through the top surface of the insulation layer, the staple capable of retaining the heating element on the top surface of the insulation layer during repeated temperature cycles of the heating element.

A heating unit comprising:

• a pan having a generally flat base and a circumferential sidewall;
• an insulation layer having an insulation base and a circumferential sidewall, the insulation layer resting at least partially inside the pan;
• a heating element supported on the insulation base of the insulation layer;
• a plurality of staples to retain the heating element on the insulation base of the insulation layer, each staple having a base, at least one leg and at least one barb, the at least one barb attached to the at least one leg, the at least one barb and a portion of the at least one leg extending into the insulation base of the insulation layer.