| 摘要 |
The present invention relates to a cooking utensil having a double-layered structure which preserves heat efficiently as well as provides even heat distribution and to a method of fabricating such cooking utensil. The cooking utensil has a heat conduction medium charged between outer and inner shells forming a double-layered structure which is sealed by a curling machine without the use of a built-in safety valve in the wall of the cooking utensil. The method comprises the steps of placing upright the outer shell on a concaved mold, the outer shell having a flange, placing a predetermined amount of the heat conductive medium into a space defined by the outer shell placed on the first mold, placing upright the inner shell in the outer shell so that the heat conductive medium at least partially surrounds the inner shell, forming a rolled joint by curling the flanges of the outer and inner shells together a predetermined number of times to prevent the heat conductive medium from being discharging from the space even when the cooking utensil is exposed to heat. The curling of the flanges of the outer and inner shells is carried out by placing at least one curling roller against the flanges while rotating the outer and inner shells with respect to the curling roller.
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