In an electric pressure cooker there is an inner cooking pot. It is removable. It is normally made of aluminum or stainless steel. The pot may have a copper-clad bottom for uniformed heating. There is a lid that is a removable or hinged cover for closing the opening of the exterior pot. The lid has a rubberized gasket or sealing ring. When the lid is locked on the cooker top, the gasket of the lid pressed on the edge of the inner pot. The arrangement creates the inner pot airtight. As the air inside the inner pot is locked, the pressure inside this chamber increases with increasing temperature. One pressure release valve is always essentially provided with the lid.
This is a kind of float valve. If the pressure inside the chamber crosses its safety limit, it operates to release the extra pressure.
In addition to inner pot, top lid with pressure release safety valve, there are other three essential parts in electric pressure cooker housing. These are an electrical heating element, pressure-temperature controller and pressure-temperature sensor. The temperature and pressure of inner pot are monitored by associated sensors.
The controller is normally a microprocessor-based system. The operation time, temperature and cooking cycle can be pre-adjusted by the controller. There must be a protection scheme provided with the system. If undesired operating condition reaches, there must an alarming system to alert by signal and sound. The system may also cut the supply to the heating element to stop the operation entirely.