The insulated lunch box is composed of ordinary lunch boxes, with an insulated shell, the inner and outer layers filled with foam plastic, and the inner layer plated with metal film.
Reduce the heat loss caused by conduction, radiation and convection, and install an electric heating device between the lunch box and the shell to supplement the heat loss and keep the food at a certain high temperature.
Extended data:
Buy common sense:
1. Simple identification method of thermal insulation performance: pour boiling water into a thermos cup, tighten the cork or lid clockwise for 2-3 minutes, and then touch the outer surface of the cup by hand. If the temperature of the cup (kettle) is obviously rising, especially if the lower part of the cup is hot, it means that the product has lost its vacuum degree and cannot achieve good insulation effect, but the lower part of the thermos cup is always cold.
2. Sealing performance appraisal method: Fill a glass of water for four or five minutes, or shake it a few times to verify whether there is water leakage.
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