Abstract: A system, utilizing an analog pulsed signal, is for monitoring the condition of a system, by way of illustration, a multi-circuit electrically heat-traced substrate. The system senses the temperature of the substrate at the end of a heat traced circuit, converts the temperature to a pulsed signal, and drives the pulsed signal along the heat tracing to the control and distribution panel for the heat tracing in direct opposition to the AC which powers the heat tracing. A receiver converts the pulsed signal to a digital temperature read-out. Utilization of an analog pulsed signal enables the system to be used in a multi-circuit system without interference or signal mixing from adjacent circuits.

Abstract: An external circuit that works in conjunction with the existing tank thermostatic controls to control both a heat pump and existing resistance elements in compliance with existing governmental codes. At the same time, this circuit disables the resistive heating elements in the hot water tank and enables the heat pump connected thereto so that the heat pump heats the water in the hot water tank. The control of the operation of the heat pump is provided through the thermostat(s) in the existing tank circuitry in the hot water tank which normally controls the resistive heating elements. At the same time, the electric resistive heating elements remain available for standby use. Further, the circuitry of the invention precludes the simultaneous operation of the electric resistive heating elements in the hot water tank and the heat pump heating unit.

Abstract: A power control system for operating a heating element in a cooking appliance in response to the selection of one of a plurality of user selectable power settings. Approximate heating element temperature information is provided by a heater energy counter. Each power setting has associated with it a corresponding steady state power level and a corresponding predetermined steady state energy count. The steady state energy count is approximately proportional to the steady state operating temperature of the heating element when operated at its corresponding steady state power level. The energy counter is selectively incremented and decremented to approximately track the heating element temperature when the count is respectively less than or greater than the steady state count for the applied power level. At least certain ones of the power settings have corresponding minimum threshold counts less than the steady state counts and maximum threshold counts greater than the steady state counts.

Abstract: A tubular heater in which a safety fuse or a PTC-element, a sensor for an electronic circuit or a thermostat is disposed as an overload safety means in the non-heated end region of the tubular heater.

Abstract: There is disclosed a modular contact lens disinfecting system comprising a combination carrying case-and-heater module including a pair of receptacles for receiving a pair of contact lenses therein, a heating arrangement responsive to a predetermined electrical current for producing heat and positioned and configured for radiating heat to the receptacle, and electrical connectors coupled with the heating arrangement for receiving electrical current; and an energizing-and-timer module including a housing, an AC plug coupled with the housing for coupling an AC receptacle to receive electrical current, mating electrical connectors coupled to the housing for complementary mating with the electrical connectors of the case-and-heater module, and a timer coupled in electrical circuit intermediate the plug and the mating electrical connectors for controlling the time duration during which electrical current is applied to the mating electrical connectors.

Abstract: A dual stage thermostat for an electrical space heating system in which there are two microswitches connected in parallel and operated by a common bimetallic strip. The first switch when closed connects a heating element to a power supply through a diode which reduces by half the power applied to the element. The second switch when closed connects the heating element directly to the power supply. The temperature at which the second switch opens is set about 1.5.degree. F. lower than that at which the first switch opens. Thus, as the room temperature approaches the desired temperature, the heater element is switched from full to half power, producing less temperature overshoot and saving energy. The thermostat may be used with any standard two wire heater.

Abstract: An alarm system for detecting popular home emergency conditions employs cooking, fire, and burglar sensors. Either or all of these sensors can activate the alarm. The system can produce distingushable alarm signals according to different violated conditions detected by different sensors. Additional functions of fire panic, burglar panic, timing, and using cooking sensor for fire sensing, are provided for convenience. The cooking sensor is equiped with an arm to sense the temperature of a cooking container. Automatic reset and turn off functions are provided for burglar alarming.

Abstract: An electrical heating apparatus protected against an overheating condition is disclosed. It includes an electrical heater and an elongate heat sensor disposed in a thermally responsive relationship. The heat sensor consists of a single conductor having positive temperature coefficient electrical impedance characteristics continuously along its entire length. The electricity flowing through the electrical heater is controlled in response to a signal from the heat sensitive conductor.

Abstract: A heat tracing tape which can be cut to required lengths has a heating element comprising at least two lengths of woven or braided resistance wire each in the form of a flat strip. The strips are encased in extruded silicone rubber whereby they are spaced from one another. The strips are electrically connected at one end by a connector and the tape is provided with a power supply termination either at its other end, or at a T-branch connection, for connecting the tape to the power control system. The power control system is adjustable to set an estimated value of power required to maintain a predetermined process temperature. The system automatically adjusts the power supplied to the tape to the estimated value by means of a feedback control system. A process temperature sensor also regulates the power supplied to the tape in accordance with a sense temperature.

Abstract: This invention relates generally to thermal control apparatus wherein a change in temperature is transmitted from a sensing bulb through a capillary to a control device. More particularly this invention is related to a novel, fail-safe control device for use in conjunction with a temperature sensing bulb, capillary, and control device in an oven or other heating facility whereby a loss of pressure within the bulb, capillary, control device system will cause the heating device to be shut off and thus will prevent the oven or other heating facility from being overheated.

Abstract: An arrangement for monitoring the approximate temperature of a resistive heating element selectively energized at a plurality of power levels in response to the selection by an operator of one of a plurality of power settings including OFF, which includes a heater energy counter to provide approximate heating element temperature information. The heater energy counter is incremented at a rate which is approximately proportional to the rate of increase of the temperature of the heating element when energized at the selected power level. In one form of the invention, the counter is decremented when a lower power setting or an OFF setting is selected, at a rate which is approximately proportional to the rate at which the temperature of the heating element decreases in cooling down to the temperature level associated with the new power setting. By this arrangement, the count of the counter approximately tracks the heating element temperature, thereby providing approximate temperature information.

Abstract: A temperature controller for a deep fat fryer including a temperature sensing circuit that determines the temperature of cooking oil in the deep fat fryer and which is connected to a temperature control circuit that controls the deep fat fryer heat source in providing heat to the cooking oil in response to a set temperature from an external input device. The control circuit also includes an anticipation circuit that variably modulates the heating source before the cooking oil temperature approaches the set temperature. The temperature control circuit further includes a resistor divider network that provides selected voltages representing reference temperatures and which are input to several operational amplifiers for controlling the heat source.

Abstract: A self-regulating heating article comprising a layer of material exhibiting a positive temperature coefficient of resistance (PTC) and said PTC layer having at least partially contiguous therewith at least one layer of constant wattage output material. The article operates such that when connected to an electric power source, the current flows through at least a portion of the thickness of the PTC layer and of the constant wattage layer. In a preferred embodiment, upon heating the article, a change in dimensions as well as activation of an adhesive occurs.

Abstract: Electrical systems, especially elongate heating systems, include means for monitoring circuit continuity and/or absence of ground faults. The systems comprise a switching device, e.g. a thermostat, as well as a circuit breaker. When the switching device is on, a relatively high current passes through the circuit and when it is off, little or no current passes through the circuit. In one embodiment, a small controlled residual current flows in the circuit even when the switching device is off, and a current-detecting device signals when a discontinuity causes the current to drop below the expected value for the residual current. In another embodiment, the switching device is placed so that the heater (or other electrical load) is at a positive potential with respect to ground even when the switching device is off, and a ground fault indicator is used to compare the currents in the two legs of the circuit and to signal when a ground fault causes the currents to differ.

Abstract: A heating device designed to be used within a refrigerated environment is provided with at least a first plate which is electrically insulated from an underlying resistance heater circuit. Plural insulating layers beneath the resistance heater reflect heat back toward the plate. The entire assembly is sealed against moisture.

Abstract: A warmer for heating wet dressings and other articles disposed in a combined heating and storage compartment in stacked relation insures that a bottommost article about to be dispensed is at a proper temperature so as to avoid burning the patient to whom the article is applied. The articles in stacked relation rest on a thin aluminum plate to which an electrical heater is connected for supplying thermal energy thereto, the plate having a center aperture forming a thermal island in which a first thermal sensor is disposed which projects into the compartment in contact with the bottommost one of the articles therein. A circuit board has control circuitry for the heater thereon and is disposed beneath the plate so as to simultaneously function as a stiffener for the plate. The control circuitry is connected to the first sensor as well as to a second thermal sensor which is directly responsive to the temperature of the heater.

Abstract: Automatic control system for controlling the switching point of a device which operates in at least two modes of operation, provides for automatic modification of the error signal which controls the switching action of the device by processing in real time the error signal to generate a resultant signal representative of the variation of the error signal over a time period, and then employing the resultant signal to modify the effect of the reference signal from which the error signal is derived. The control system can be employed in a chemical analysis instrument to control the on-off operation of a heater which supplies heated air to incubate samples.

Abstract: An energy regulator for a household heating appliance such as an electric cooker comprises an electronic controller for the cyclical control of the supply of electrical energy to a heating element and a switch for increasing the electrical energy supplied to the heating element to a preselected level and for a preselected time. The preselected time may be variable in dependence on the duty cycle of the controller, the duration decreasing from about thirteen minutes at low duty cycle to one minute or less at high duty cycle. Actuation of the switch may cause the electrical energy to be increased to substantially 30% of full heating power at low duty cycle rising to substantially 100% of full heating power at high duty cycle.

Abstract: An electric heater for heating oil contained in the sump well of a compressor includes a thermally conductive shell having first and second opposed inner surfaces. A ceramic core having a D-shaped cross-section throughout is positioned in the shell and is provided with longitudinal channels which are disposed substantially the same distance from the outer curved surface of core. An electric resistance heating element is disposed in the channels and is energizable by a source of power for developing heat under the control of a thermostat disposed in the shell. A resilient pad of ceramic fiberglass material having low thermal conductivity is disposed between the flat surface of the core and the thermostat and urges the curved surface of the core and the thermostat into contact with the opposed inner surfaces of the shell while substantially blocking heat transfer therethrough from the heating element to the thermostat.

Abstract: A glow plug control circuit uses two normally closed thermally actuated switches in series with a power relay and a timer switch across the battery when the ignition switch is turned on; the power relay connects the glow plugs to the battery. At least one of the two switches cycles on and off to limit the temperature of the glow plugs. Another normally closed thermally operated switch has a heating element in series with the glow plugs for turning off a lamp after the glow plugs are energized for a predetermined time. If one or more of the glow plugs are open-circuited, the lamp is cycled on and off with the cycling on and off of current through the glow plugs by the power relay, to signal a fault condition.

Abstract: A controlled temperature oven provided with a pyrometer having a temperature sensitive resistance, an electrical heating element, a nonlinear heat sensing element within the oven chamber, and a variable power supply electrically connected to the heating element, the variable power supply being controlled in response to the nonlinear heat sensing element, and a switch assembly having a plurality of pairs of single pole double throw switches with a common actuation member for each pair of switches, one switch of each pair being connected in a first cascade of switches and the other switch of each pair being connected in a second cascade of switches, the switches of the first cascade of switches connecting one of a plurality of manually adjustable resistors to the variable power supply to control the output thereof, and the switches of the second cascade of switches connecting one of a plurality of variable resistors to the pyrometer to indicate the temperature selected by the switches of the first cascade of sw

Abstract: A glass ceramic top cooker has at least one radiant heater arranged beneath the glass ceramic surface, the or each radiant heater comprising a continuous base layer of electrical and thermal insulating material, a peripheral wall also of electrical and thermal insulating material, and a heating element arranged on the base layer. The radiant heater also includes means, such as a pad, disposed on the base layer for isolating a region within the peripheral wall from heat emitted by the heating element and a temperature sensor, such as a thermocouple or a platinum resistance, mounted within the isolated region so as to be sensitive in use substantially only to the temperature of a cooking pan which is heated by the heater. The temperature sensor is effective because there is created on the glass ceramic plate a cold patch through which the temperature of the pan can be determined.

Abstract: A heater for cups and fluids therein having an adjustable heat selector, heating circuitry and temperature stabilization circuitry, comprising a base support, an electrical circuit enclosing housing, an opening in an upper substantially horizontal surface of the housing for a heating element plate and heat sensor, and an upright section of the housing enclosing additional circuitry having a vertical, substantially cylindrical surface facing the heating element plate, substantially rectangular vertical surfaces for the remaining three sides of the upright section, the vertical substantially cylindrical surface and the substantially rectangular vertical surfaces forming an open-topped receptacle having inner partitions and a closed bottom for receiving assorted personal articles.

Abstract: An electric rice cooker is disclosed which has a cooking pot or kettle for containing rice and water, a removable lid member covering the top of the kettle, an electrical heater provided adjacent to the outside surface of the kettle for heating the kettle and the contents thereof, a thermal insulating frame structure, and a control section which includes a kettle temperature detector and a control circuit for controlling the heater so as to allow the rice to automatically and properly absorb water in accordance with the actual kettle temperature immediately after the cooking operation is started, but before the rice is substantially changed to alpha-starch.

Abstract: An electrical heating apparatus, and particularly a bedcover preferably in the form of a blanket, protected against an overheating condition and in which electrical current flow through a heating element is controlled by a pair of gate controlled bidirectional semiconductor switches electrically connected to one another in series and in back-to-back orientation. The gates of the semiconductor switches are connected through a temperature sensitive capacitor which triggers the semiconductor switches from a conductive to a nonconductive state in response to the sensing of an overheating condition.

Abstract: An electric cooker or cooking hob has a ceramic plate 2 on which there are a number of hot plate areas each heated by a respective annular heating element 4 disposed within an insulating housing 7. A temperature dependent resistor 9 is disposed below the hot plate area at the center of focus of a reflector 8 which is arranged to focus radiant energy from the hot plate area onto the resistor 9 while at the same time shielding the resistor 9 from direct radiation from the electric heating element 4. The signal derived from the resistor 9 is a measure of the temperature of the hot plate and can be used to provide a thermal tripping function to prevent over-heating of the hot plate area and/or to carry out closed loop control of the temperature of the hot plate area. The reflector 8 may be replaced by a shield which shields the resistor 9 from direct heating by the heater.

Abstract: A control system for a top plate surface heating unit having a softening temperature. The control system incorporates a temperature setting means for determining the operating temperature of the surface heating unit and means for automatically limiting the temperature of the surface heating unit to a temperature below the softening temperature of the top plate.

Abstract: A cooker apparatus for heating a cooking pot inductively comprises an induction heating coil and a control device for controlling the heating power. The control device has a temperature-dependent guiding and control means and a sensor unit, adapted to be positioned on the cooking pot and subjected there to the evolution of steam in the cooking pot. The sensor unit is arranged to transmit control signals to the guiding and control means.

Abstract: A heater for heating liquids such as water in an aquarium comprises a water-impermeable housing including a heating section for immersion in the water. Within the heating section of the housing is a flexible, distributed planar heating element. The housing is resistant to breakage from mechanical and operating abuse and has a high heat transfer coefficient and high heat distortion temperature. To prevent the housing from melting when a control element of the heater malfunctions, preferably the aquarium heater includes temperature limiting means such as a circuit protection element comprising a material having a positive temperature coefficient of resistance. Preferably, the heating section of the housing is fabricated with large surface area walls to accommodate the planar heating element, and is provided with coupling means for maintaining the heating element thermally coupled to the walls of the heating section.

Abstract: A flat, normally horizontal electric resistance blanket heater comprising a thin, fragile elongate resistance element on one surface of and carried by a thin, flexible sheet of dielectric material, a thin, flat resilient and flexible reinforcing strate of dimensionally stable material retained adjacent the other surface of the film to permit flexure of the heater and without dimensional distortion of the film and element and a flexible envelope encapsulating the sheet element and strate.The heater also includes temperature responsive switching means responsive to the temperature of heated portions of the heater and in temperature insulated relationship from a portion of the heater where the element connects with power supply lines and which creates a portion in the heater of increased mass and heat storing capacity.

Abstract: A control circuit for a glow plug assembly serving as an engine preheating apparatus is designed so as to effect a temperature control in conformity with the specified position established by selective operation of a key switch having three switching positions, i.e., OFF, ON and START positions. The control circuit comprises a first switch connected between the glow plug assembly and a power source, and a series circuit comprising a second switch connected parallel with the first switch and a resistor.

Abstract: The control device has a power regulator for the timed power to the heating system of the electrical apparatus. The heating system is provided with a temperature sensor which, up to a given desired temperature, bridges the power regulator with the aid of a temperature switch, so that full power is supplied to the electrical apparatus heating system. On exceeding the desired temperature, power is supplied to the electrical apparatus via the power regulator.The temperature sensor is additionally heatable by an auxiliary heating system to obtain a variable changeover temperature of the temperature switch (22).The auxiliary heating system is preferably always switched on when the heating system of the power regulator is switched off.

Abstract: An elongated heater unit including an elongated resistor helix, terminals connected to the ends of the helix, at least a first surrounding metallic sheath, powder insulation material disposed within the first sheath and spacing the resistor helix from the sheath. The sheath is provided with at least one indentation and/or groove extending along at least a portion of the length of the first sheath. The method for constructing the heater unit includes forming the indentation by means of a roll with a protrusion, by utilizing a mandrel, by utilizing a temperature sensitive member or by utilizing a reducing sheath.

Abstract: An energy-saving electronic thermostat operates by means of a single temperature probe. The rapid decrease in temperature of the probe when a window is opened causes the heating to be switched off or reduced by means of a comparator circuit combined with a network having a large time-constant. The device is employed in a fixed or mobile electric heating convector.

Abstract: A plastic reinforced fiberglass container has heating element integrally bonded into the container's interlaminate structure and preferably between the corrosion liner and the structural lamina to permit efficient heating of the container contents. A thermocouple is also embedded in the interlaminate structure and preferably positioned at the same location to achieve sensitive temperature control of the container's contents.

Abstract: A thermostatic control for electric cables used on overhanging eaves of pitched roofs in northern climates, and in rain gutters and downspouts, comprises a high temperature-limit switch and a low temperature-limit switch connected in series circuit for controlling energization to a narrow temperature range extending from the freezing temperature of water to several degrees colder. Above-freezing temperatures will melt ice and snow without supplemental heating, and sufficiently colder temperatures will not be raised sufficiently by heat loss through a building roof to thaw ice and snow accumulation on the roof and provide run-off water to the unheated eave, rain gutter and downspout where freezing can occur and result in the formation of an ice dam which will block drainage of further run-off water and which may grow in size to cause water to back-up and seep under roofing shingles to leak through the roof.

Abstract: A self-regulating heating article comprising a layer of material exhibiting a positive temperature coefficient of resistance (PTC) and said PTC layer having at least partially contiguous therewith at least one layer of constant wattage output material. The article operates such that when connected to an electric power source, the current flows through at least a portion of the thickness of the PTC layer and of the constant wattage layer. In a preferred embodiment, upon heating the article, a change in dimensions as well as activation of an adhesive occurs.

Abstract: An electric heating system employs a control unit including means to connect a resistance heater to a three pole power source and a switch to switch the connections between full voltage and low voltage as temperature is more than or less than several degrees colder than the set temperature. More uniform heating, greater comfort and significant energy savings results.

Abstract: Electrical devices which comprise two planar electrodes and a conductive polymer element, at least a part of which is a PTC element. The conductive polymer element has an intermediate portion of increased resistance, resulting from the presence of insulating or high resistance portions within the conductive polymer element, so that when a hot zone is formed in the PTC element, it is located at or near the intermediate portion, away from the electrodes.

Abstract: An electrical heating apparatus, and particularly a bedcover preferably in the form of a blanket, protected against an overheating condition and in which electrical current flow through a heating element is controlled by a pair of gate controlled bidirectional semiconductor switches electrically connected to one another in series and in front-to-front orientation. The gates of the semiconductor switches are connected through a temperature sensitive capacitor which triggers the semiconductor switches from a conductive to a nonconductive state in response to the sensing of an overheating condition.

Abstract: The invention relates to novel electrical devices which are useful for example as heaters and temperature sensors, and which comprise at least two electrodes, at least one PTC element, at least one relatively constant wattage element, and at least one current-directing element which directs the current, when the device is first connected to a source of electrical power, so that the effective initial resistance of the device is greater than it would be in the absence of said element. Thus the invention provides a solution to the problem of current inrush in application of PTC devices in which substantial current passes through the device at operating temperatures. The invention also includes the use of the novel devices in applications in which current inrush is not a problem.

Abstract: A cooker apparatus for heating a cooking pot inductively comprises an induction heating coil and a control device for controlling the heating power. The control device has a temperature-dependent guiding and control means and a sensor unit, adapted to be positioned on the cooking pot and subjected there to the evolution of steam in the cooking pot. The sensor unit is arranged to transmit control signals to the guiding and control means.

Abstract: A control circuit for electrically heatable windshields of automotive vehicles which controls the quantity of heat supplied by the vehicle alternator to the windshield heating element to be adequate for deicing the windshield yet limited to avoid windshield damage and to minimize decoupling time of the alternator from the vehicle battery. The control circuit, which employs an inexpensively installed temperature sensor element that senses ambient temperature, responds to the temperature difference between the ambient and a reference deicing temperature and to the supplied heating power for controlling the duration of the heating period.

Abstract: A heater for heating liquids such as water in an aquarium comprises a water-impermeable housing including a heating section for immersion in the water. Within the heating section of the housing is a flexible, distributed planar heating element. The housing is resistant to breakage from mechanical and operating abuse and has a high heat transfer coefficient and high heat distortion temperature. To prevent the housing from melting when a control element of the heater malfunctions, preferably the aquarium heater includes temperature limiting means such as a circuit protection element comprising a material having a positive temperature coefficient of resistance. Preferably, the heating section of the housing is fabricated with large surface area walls to accommodate the planar heating element, and is provided with coupling means for maintaining the heating element thermally coupled to the walls of the heating section.

Abstract: A flat normally horizontal electric resistance blanket heater comprising a thin, fragile elongate resistance element established on one surface of and carried by a thin, flexible film of dielectric material, a thin, flat resilient and flexible reinforcing strate of dimensionally stable material retained adjacent the other surface of the film to allow for controlled flexure of the heater and prevent dimensional distortion of the film and element and an envelope of flexible dielectric plastic film encapsulating the film, element and strate.The heater also includes temperature responsive switching means responsive to the temperature of heated portions of the heater and in temperature insulated relationship from a portion of the heater where the element connects with power supply lines and which creates a portion in the heater of greater mass and heat storing capacity.

Abstract: An improved oven (10) for maintaining the junctions of a plurality of reference thermocouples at a common and contant temperature. The oven (10) is characterized by a cylindrical body (12) defining a heat sink having an axially extended cylindrical cavity (14), a singularized heating element comprising a unitary cylindrical heating element consisting of a resistence heating coil (20) wound about the surface of a metallic spool (18) having an axial bore (22) defined therein and seated in the cavity, an annular array of radially extended bores (30) defined in the cylindrical body (12) and a plurality of reference thermocouple junctions (32) seated in the bores in uniformly spaced relation with the heating element, and a temperature sensing device (28) seated in the axial bore for detecting temperature changes as they occur in the spool and circuit (46) for applying a voltage across the coil in response to detected drops in temperatures of the spool.

Abstract: A plastic injection molding system having a temperature controlled electric heater element.The heater element is formed by disposing a pair of heater wires and a pair of thermocouple wires and a powdered mineral material in a metal sheath which is subjected to repeated drawing and annealing operations and is then cut to a desired length after which at one end, the heater wires are welded together and the thermocouple wires are welded to the sheath and the sheath is welded to form a closed end wall. At the opposite end, the heater and thermocouple wires are connected through connection means and connection wires to a current supply and a temperature sensing circuit. The sheath is in the form of a rightly wound helical coil structure and is installed in direct heat transfer engagement on a cylindrical surface of a metal part which has an axially extending plastic flow passage therein.

Abstract: A heating circuit, in particular for an electric blanket or pad, comprises an elongate heating conductor and switch connected in series between input terminals for connection to an AC supply. Switch control is operative to close the switch to cause current to flow through the heating conductor. The circuit further comprises a sensor conductor coextensive with the heating conductor, and a temperature sensitive resistance coextensive with the heating and sensor conductors and having an impedance that falls with increasing temperature. A resistor is connected in series with the sensor conductor such that a current dependent on the impedance of the temperature sensitive resistance flows through the resistor, whereby the voltage across the resistor varies with said impedance. Voltage sensing structure is responsive to the voltage across the resistor reaching a predetermined value to inhibit operation of the switch control, thereby to provide normal and/or overtemperature control.

Abstract: The invention relates to novel electrical devices which are useful for example as heaters and temperature sensors, and which comprise at least two electrodes, at least one PTC element, at least one relatively constant wattage element, and at least one current-directing element which directs the current, when the device is first connected to a source of electrical power, so that the effective initial resistance of the device is greater than it would be in the absence of said element. Thus the invention provides a solution to the problem of current inrush in applications of PTC devices in which substantial current passes through the device at operating temperatures. The invention also includes the use of the novel devices in applications in which current inrush is not a problem.

Abstract: Contact lens disinfector unit for sterilizing contact lenses contained within a lens case, wherein the contact lenses are of the type which preferably should be sterilized or disinfected once each day and periodically cleaned after a predetermined number of sterilizing or disinfecting cycles. The heating unit includes a housing in which is disposed a heating block arranged to contact the lens case, and circuit means operatively associated with the heating block and adapted to be coupled to a source of electric potential for utilizing electric current to apply heat to the heating block. The circuit applies the electric current for a sufficient period of time to attain a desired sterilizing temperature within the case, and then terminates the heating cycle allowing the lens case and the contact lenses to cool, thereby completing the overall sterilizing cycle.