Conventional pressure cookers were made to be used on stove top.A steam regulator,safety valve and pressure-activated interlock mechanism provide protection agaist the overheating and the danger of explosion.When a preset pressure is reached in the cooker, the steam regulartor is pushed up by the built-up pressure to allow thesteam to escape.This is the reason why the conventional oven top pressure cookers generate loud and disturbing hisiing noise when the pressure is on.
Electric pressure cooker is an ingenious invention in the last decade.Historians are stillundecided about inventors and the precision time.Arguably, a Chinese scientist ,Mr Yong-guang wang, filed the first electric pressure cooker patent on January 9th,1991(patent NO. ZL91100026.7). This patent is currently owned by the NO.1 electric pressure cooker manufacturer Midea.
Electric Pressure Cooker consists of a pressure cooking container (a.k.a. inner pot or cooking pot), the electric pressure heating element and temperature / pressure sensors.The heating process is controlled ny the built-in sensor and pressure switch. When the pressure inside reaches the limit the heating element will stop working and till the pressure inside is lower than set, it will start working again untill reahes to the set working pressure. Thatls why the electric pressure cooker is safer and energy saving.