Thermal signal device with timer

An indicating apparatus for the temperature in a compartment of a refrigerator comprising:

• a direct current source of electric energy such as a battery;
• said battery electrically isolated from any other source of electrical energy;
• hermetically sealed thermal responsive means adapted to be positioned within said compartment and in circuit with said source of electrical energy, electrical indicating means positioned outside said refrigerator and in circuit with said source of electrical energy, a detachable electrical connection in said circuit between said thermal responsive means and said indicating means, said thermal-responsive means being pre-set for an "off" position below a predetermined degree of temperature within said compartment, but adapted to be moved automatically to an "on" position, whenever the temperature in said compartment rises above said pre-set degree of temperature, switch means operable by said thermal responsive means to close the circuit through the indicating means in response to an increase of temperature in said compartment above said pre-set temperature, so as to give an indication that the temperature within such compartment exceeds said pre-set temperature of said thermal-responsive means, and timing means electrically connected to the circuit to detect the presence of electrical current through the electrical indicating means to determine how long the temperature within the compartment exceeds the pre-set temperature of the thermal-responsive means, said circuit between said source of electrical energy and the switch means being normally open so long as the temperature in said compartment is below said pre-set temperature of said thermal-responsive means.