Food steamer with automatic electric steam trap, power modulation and automatic connected water supply

摘要

A steam cooker has an insulated housing that surrounds an internal cooking compartment accessible through a door. In one form, a supply of water is held in the compartment and immerses a plate-like resistance heating element mounted at the floor. Water is automatically added to this supply when both 1) a water level sensor indicates a refill, and 2) a door switch signals that the door is open. these signals together open a normally-closed solenoid valve in a water feed line. A steam outlet located above the maximum water level is in fluid communication with and adjacent another electrically-operated solenoid valve that is normally open to atmosphere. In one mode of operation, a temperature sensor in close physical proximity to the steam outlet and the solenoid valve closes the solenoid wherein the sensed steam temperature is at or above a set level. The outlet steam is also connected to a pair of water column pressure-responsive microswitches that control power to the heating element and, if there is an over-pressure, to open the solenoid valve to vent the steam to atmosphere. Plural such steam cookers can operate in parallel stacked in a single cabinet, and each capable of operating in a fast cook mode where the water and power savings advantages of the electric steam trap are disabled or adjusted.