Design News for Mechanical and Design Engineers

San Diego, CA--Have you seen the TV ad where a pizza-delivery guy rides inside a steaming-hot vehicle to deliver a piping-hot pizza to the customer? Then you see a Domino's counterpart making a delivery of a sizzling pie in a pizza-size box in cool comfort. What's the secret behind that novel "hot box?"

"We were looking for a way to encase our unique Phase Change Material (PCM) and its ability to maintain high temperatures over an extended period," explains Sigurd Frohlich of Phase Change Laboratories. "We've all heard the pleas from the food industry for serving up fast, hot, and fresh food. More specifically, pizza companies, which promise piping-hot pizza deliveries to the customer's front door in 30 minutes or less, wanted a product to help keep the 'hot' promise."

Phase Change Laboratories holds the exclusive right to manufacture and market the proprietary PCM. The result of research by Ival Salyer at the University of Dayton Research Institute, the material can reversibly absorb and release heat for long periods and at a constant temperature during melting and freezing.

Co-Mack created a design for a circular plate or biscuit (11.5 inches in diameter) of PCM to be easily inserted inside an injection-molded shell the size of a large pizza pan. By using a durable polycarbonate blend, the shell could withstand the heat of a low-temperature oven or microwave. The external molded shell lets heat pass through at temperatures as high as 220F without melting.