Yogurt fermenter and automatic temperature control method therefor

A yogurt fermenter comprising:

• a body for storing a fermentation material and having a heating element disposed at a lower portion thereof and a temperature sensor built on an upper portion of a side thereof;
• and
• a controller for controlling a heating value of the heating element according to a predetermined control logic on the basis of a temperature measured by the temperature sensor,
• wherein i) if the temperature measured by the temperature sensor is lower than a first fermentation reference temperature, the controller allows the heating element to supply a first heating value, ii) from a time point where the temperature measured by the temperature sensor reaches the first fermentation reference temperature, the controller controls the heating value of the heating element to allow a temperature of a fermentation material to be convergedly maintained to a second fermentation reference temperature as a target value on the basis of the temperature measured by the temperature sensor, and iii) the controller allows the heating element to supply a second heating value having a size less than half of the first heating value from a time point coming earlier by predetermined spare time than a time point where temperatures at the upper and lower portions of the fermentation material are reversed to cause the temperature at the upper portion of the fermentation material to be lower than the temperature at the lower portion of the fermentation material, the first fermentation reference temperature being lower than the second fermentation reference temperature, and the spare time being less than time elapsed from the time point where the temperature measured by the temperature sensor reaches the first fermentation reference temperature up to the time point where the temperature at the upper portion of the fermentation material gets lower than the temperature at the lower portion of the fermentation material.

An automatic temperature control method for a yogurt fermenter having a heating element adapted to supply heat to a lower portion of a fermentation container and a temperature sensor adapted to measure a temperature at an upper portion of the fermentation container in real time, the method comprising the steps of:

• a) if a temperature measured by the temperature sensor is lower than a first fermentation reference temperature,
• controlling the heating element so that a first heating value is supplied from the heating element;
• b) from a time point where the temperature measured by the temperature sensor reaches the first fermentation reference temperature, controlling the heating value of the heating element to allow a temperature of a fermentation material to be higher than the first fermentation reference temperature and convergedly maintained to a second fermentation reference temperature as a target value on the basis of the temperature measured by the temperature sensor;
• and
• c) controlling the heating element so that a second heating value having a size less than half of the first heating value is supplied from a time point coming earlier by predetermined spare time than a time point where temperatures at the upper and lower portions of the fermentation material are reversed to cause the temperature at the upper portion of the fermentation material to be lower than the temperature at the lower portion of the fermentation material, the spare time being lower than time elapsed from the time point where the temperature measured by the temperature sensor reaches the first fermentation reference temperature up to the time point where the temperature at the upper portion of the fermentation material gets lower than the temperature at the lower portion of the fermentation material.