Temperature-controlled laboratory beaker comprising a heating element and temperature sensor bonded to the outer surface of the beaker by a silicone-rubber molding

Claim 1

An apparatus for heating a liquid to a set-point temperature and for automatically maintaining that temperature, comprising: (a) a beaker made of thermally conductive material; (b) an electric heater wrapped around and affixed to the outside wall of said beaker; (c) electrical means for energizing said electric heater; (d) temperature sensing means in contact with and thermally coupled to the outer surface of said beaker for developing a signal corresponding to the temperature of the beaker; (e) electronic means connected to said temperature sensing means for receiving a signal therefrom indicative of the temperature of the beaker and including means for comparing the signal so received to a set-point temperature corresponding to a temperature chosen by a user and for activating said electrical means for energizing said electric heater when the temperature corresponding to the signal is below the set-point temperature; and (f) a molding bonded to the outer surface of said beaker and formed around said electric heater and said temperature sensing means, wherein said molding completely covers the electric heater and the temperature sensing means and permanently bonds the heater and the temperature sensing means to the outer surface of the beaker; wherein said electronic means for comparing the signal developed by said temperature sensing means to a set-point temperature and for activating said electrical means for energizing said electric heater consists of an integrated circuit comparator connected to said temperature sensing means, to a rheostat for adjusting the set-point temperature, and to a triac device serving as a switch in said electrical means for controlling the current flow through said electric heater.

Claim 2

An apparatus for heating a liquid to a set-point temperature and for automatically maintaining that temperature, comprising: (a) a beaker made of thermally conductive material; (b) an electric heater wrapped around and affixed to the outside wall of said beaker; (c) electrical means for energizing said electric heater; (d) temperature sensing means in contact with and thermally coupled to the outer surface of said beaker for developing a signal corresponding to the temperature of the beaker; (e) electronic means connected to said temperature sensing means for receiving a signal therefrom indicative of the temperature of the beaker and including means for comparing the signal so received to a set-point temperature corresponding to a temperature chosen by a user and for activating said electrical means for energizing said electric heater when the temperature corresponding to the signal is below the set-point temperature; and (f) a molding bonded to the outer surface of said beaker and formed around said electric heater and said temperature sensing means, wherein said molding completely covers the electric heater and the temperature sensing means and permanently bonds the heater and the temperature sensing means to the outer surface of the beaker; wherein said electronic means for comparing the signal developed by said temperature sensing means to a set-point temperature and for activating said electrical means for energizing said electric heater consists of an integrated circuit comparator connected to said temperature sensing means, to a rheostat for adjusting the set-point temperature, and to a triac device serving as a switch in said electrical means for controlling the current flow through said electric heater.

Claim 6

A method of manufacturing an apparatus for heating a liquid to a set-point temperature and for automatically maintaining that temperature, comprising the following steps: (a) providing a beaker made of thermally conductive material; (b) wrapping an electric heater around the outside wall of said beaker; (c) providing a thermistor thermally coupled to and in contact with the outer surface of said beaker for developing a signal corresponding to the temperature of the liquid in the beaker; (d) forming a molding around and completely enclosing said electric heater and said thermistor; (e) providing a source of electric energy connected to said electric heater; and (f) providing electronic means for comparing the signal developed by said thermistor to a set-point temperature corresponding to a temperature chosen by a user and for energizing said electric heater in response to a temperature corresponding to the signal being below the set-point temperature; wherein said electronic means consists of an integrated circuit comparator connected to said thermistor and to a rheostat for adjusting the set-point temperature, and actuating a triac device serving as a switch for controlling the current flow through said electric heater; wherein said heater consists of a flexible electrical heater permanently attached to the exterior wall near the bottom of said beaker and the heater's height is chosen to approximately match the expected level of the liquid in the beaker during use; and wherein said molding consists of silicone rubber.

Claim 7

A method of manufacturing an apparatus for heating a liquid to a set-point temperature and for automatically maintaining that temperature, comprising the following steps: (a) providing a beaker made of thermally conductive material; (b) wrapping an electric heater around the outside wall of said beaker; (c) providing a thermistor thermally coupled to and in contact with the outer surface of said beaker for developing a signal corresponding to the temperature of the liquid in the beaker; (d) forming a molding around and completely enclosing said electric heater and said thermistor; (e) providing a source of electric energy connected to said electric heater; and (f) providing electronic means for comparing the signal developed by said thermistor to a set-point temperature corresponding to a temperature chosen by a user and for energizing said electric heater in response to a temperature corresponding to the signal being below the set-point temperature; wherein said electronic means consists of an integrated circuit comparator connected to said thermistor and to a rheostat for adjusting the set-point temperature, and actuating a triac device serving as a switch for controlling the current flow through said electric heater; wherein said heater consists of a flexible electrical heater permanently attached to the exterior wall near the bottom of said beaker and the heater's height is chosen to approximately match the expected level of the liquid in the beaker during use; and wherein said molding consists of silicone rubber.