A cooking apparatus employing induction heating is normally constructed so as to utilize a metal housing supporting a cook top upon which there is located at least one induction heating coil. The housing normally contains an electronic "package" for use in supplying power to the coil or coils used and a fan for circulating air through the housing so as to maintain the temperature of the electronic components employed sufficiently low that they will not be damaged by heat. In the disclosed apparatus a thermistor is mounted on the housing adjacent to the wires connecting the electronic components to the heating coil or coils used. This thermistor is used to control the flow of current through an SCR or a triac acting as a switch in a circuit containing the fan motor.

Fan speed control used in induction cooking apparatus

A circuit and apparatus for magnetically sensing fluid flow and applying voltage to a load has a spring loaded check valve disposed within a conduit and provided with a magnetic shield. A magnet is located on one side of the magnetic shield while a sensor, associated with the valve, is located on the opposite side of the magnetic shield. The check valve, and hence the magnetic shield, moves to permit fluid flow. When the magnetic shield moves due to fluid flow, the magnet activates the sensor. A load control circuit includes a supply terminal for receiving a supply voltage and a detector which detects a condition requiring the operation of a load. The detector causes a threshold voltage to be generated from the supply voltage, and a time delay controller controls the time required to generate the threshold voltage. A DIAC or equivalent element conducts to generate a first trigger signal once the threshold voltage is achieved, and a silicon-controlled rectifier (SCR) generates a second trigger signal in response to the first trigger signal. The circuit includes an opto-TRIAC and triac which are rendered conductive by the second trigger signal to cause a voltage to be provided to the load.

Apparatus for sensing fluid flow and associated load control circuit

A circuit and apparatus for magnetically sensing fluid flow through a conduit. The circuit includes a sensor and a sensor magnet for biasing the sensor in an on condition. A second magnet indicative of the relative position of a conduit valve substantially neutralizes the sensor magnet when the valve is closed to prevent fluid flow, and does not substantially neutralize the sensor magnet when the valve is open to permit fluid flow. The sensor can be a Hall effect sensor, and the sensing of fluid flow causes an indication current to flow. Circuitry is provided to apply a voltage to a load in response to the indication current.

Circuit and apparatus for sensing fluid flow

A double check valve assembly having at least one three way valve with a pressure gauge in communication with the double check valve downstream of the second check valve. A flow detection arrangement with a battery powered alarm and automatic dialer and time delay circuit is included with a test and drain valve arrangement provided downstream of the second check valve.

Double check valve assembly for fire suppression system

An accessory for a garage door opener which includes a circuit which is energized when the garage door operator is actuated and which can be used to energize a power circuit as, for example, a lamp so as to provide illumination upon energization of the garage door operator. The lamp automatically turns off after a pre-set time and can also be manually controlled by an on-off switch.

Accessory for a garage door opener

The solid state electronic timer controls the time of load energization with a bidirectional solid state switching device. Upon the operation of a timer actuating unit, a large capacitor is charged to provide a charge for a small capacitor in a relaxation oscillator circuit. The relaxation oscillator output is supplied to gate the bidirectional solid state switching device. Since the current necessary to operate the relaxation oscillator is small, timing cycles in the range of many minutes are provided without resort to physically large capacitors.

H Hoge

Papers

Solid state timer circuit for controlling the energization time of a load