Abstract: A piping leakage detecting apparatus includes a high pressure gas supply source, a gas implement connected to the high pressure gas supply source via a pipeline, and a switching device mounted on the pipeline for selectively opening and closing the pipeline. A pressure detecting device is mounted between the gas implement and the switching device for detecting the gas pressure inside the pipeline. A leakage judging device is provided to judge that gas leaks when no gas is being used and when a pressure drop is detected based on an output from the pressure detecting device, while the pipeline is being opened and closed by the switching device.

Abstract: A warming apparatus for use during sleep includes at least one of a temperature-up timer circuit for raising a temperature of an electric heater by an amount in the range of 2.degree. C. to 6.degree. C. for a predetermined time and thereafter restoring the temperature of the electric heater to a preset ordinary temperature, and a temperature-dowm timer circuit for lowering the temperature of the electric heater by an amount in the range of 2.degree. C. to 6.degree. C. for a predetermined time and thereafter restoring the temperature of the electric heater to the preset ordinary temperature, each of the temperature-up timer circuit and the temperature-down timer circuit being actuated while the warming apparatus is in operation.

Abstract: In a bed warmer such as an electric blanket initially subject to a preparatory high temperature set value, the supply of power to a heater is controlled such that a warmer temperature is automatically recovered to a preset temperature value provided by a temperature setter from the preparatory high temperature set value when a bodily temperature detector detects that the user has goes to bed.

Abstract: A system comprising a heat generating load such as a heater, a power control element for directly or indirectly supplying current to the heat generating load, a temperature detecting circuit for producing an ON signal when the temperature of the heat generating load is lower than a set temperature and an OFF signal when the temperature is higher than the setting, and a control circuit for feeding an ON or OFF signal to the power control element in response to the ON or OFF signal from the temperature detecting circuit. The control circuit includes a failure detecting circuit for logically comparing the signal from the temperature detecting circuit with the terminal voltage across the power control element to produce output when the power control element is in conduction although the signal from the temperature detecting circuit is an OFF signal.

Abstract: A system comprising a heat generating load, a power control element for controlling power supply to the heat generating load, a temperature detecting circuit for producing an ON signal when the temperature of the load detected by a temperature sensor is lower than a set temperature and an OFF signal when the temperature has reached the set temperature, and a control circuit for feeding on ON or OFF signal to the power control element in response to the signal from the temperature detecting circuit. The control circuit includes a hysteresis control circuit which, once the temperature detecting circuit detects that the temperature has reached the set temperature, permits the power control element to receive OFF signals for a suitable period of time even after the temperature has subsequently lowered to a level at which the signal from the temperature detecting circuit changes to an ON signal.