Abstract: The domestic and commercial automatic soil moisture indicator of the present invention employs a pair of probes which are conductive traces (e.g. a printed circuit board) that are coated with material for corrosion and electrolysis resistance to enable long term residence in potted plant soil. The device provides alternating short pulses across the probes to further enhance near zero electrolysis and increase potted plant soil residence time without probe wear. It has a single light emitting diode indicator lamp to blink every ten seconds when soil drops below a customer set level, and a beeper (e.g. piezoelectric ceramic) to sound a beep in unison with the LED flashing during dry soil indication as well as a calibrated-numbered user adjustment to set the dry soil indication level. A coil operating with an integrated circuit DC to DC converter functions to yield operation from a small battery to keep the overall unit small and electric drain down.

Abstract: An electrical warning system for malfunctions in refrigeration equipment driven by an electric motor comprises a main resistor connected in series with the motor to cause only a small voltage drop in the power supply to the motor, a high amp shunt across the main resistor comprising a diode, resistor and light-emitting diode, and a low amp shunt across the main resistor comprising a diode and light-emitting diode with the latter having in parallel a capacitor as well as a resistor in series with a zener diode.

Abstract: This is a method, and apparatus for practicing the method, by which electrical fuses or circuit breakers which have become inoperative by failure or overload can be instantly identified. The method and apparatus involves the use of light emitting diodes or the like connected in parallel with fuses in such a manner that when a fuse or circuit breaker fails in carrying an electrical load the flow of electrical current will be diverted to the light emitting device and cause it to visually signal the failure.

Abstract: A smoke alarm for responding to alarm conditions using electrical circuitry having a horn coil placed in series with rectifier circuitry. The series connection of the horn coil with the rectifier circuitry enables suppression of line transients and also eliminates the need for additional transient suppression circuits. An alarm condition causes generation of a short circuit which activates the horn and causes current to pass through the horn; but the high impedance of the horn coil in the rectifier circuit limits the amount of current drawn to low levels for more efficient and safe operation of the smoke alarm. Further, the current flow in the horn will be substantially AC as a result of the series connection of the horn and rectifier circuitry, thereby eliminating the need for an alternate reset current path.

Abstract: A bi-directional system for ensuring that a ground connection is made in a three-wire conductor system including a line "hot" conductor, a line neutral conductor, and a ground conductor includes a circuit for generating direct current potential related to the potential difference between the line "hot" conductor and ground and a second circuit for generating a direct current potential related to the potential difference between the line "hot" conductor and ground. A circuit including a male plug for insertion into a female receptacle includes a first prong for coupling alternatively to the line "hot" conductor or the line neutral conductor, a second prong for coupling alternatively to the line "hot" conductor or the line neutral conductor, and a third prong for coupling to the line ground conductor.

Abstract: A heavy rain rate warning indicator having a housing which has a first opening in the top and a second opening in the bottom. A rain collector/feeder is located in the first opening for directing collected rain in a stream onto a flat plate, pivotally mounted within the housing. A predetermined amount of movement of the flat plate causes the activation of a switch which in turn provides a signal to an alarm system indicative of heavy or severe rainfall. In addition, a gear arrangement can be operably connected to a support rod for the flat plate in order to provide instantaneous rain rate information.

Abstract: An apparatus for detecting the presence of granular material at a predetermined location in conduit adapted to contain the flow of granular material and in containers adapted to store granular material, wherein the upper portion of a sensing terminal is embedded in a protective housing. The protective housing has a material deflecting surface formed thereon and the lower portion of the sensing terminal protrudes from the protective housing opposite the material deflecting surface. The sensing terminal is adapted to exhibit a change in at least one of its electrical characteristics when the lower portion is in communication with granular material. Means are provided for mounting the protective housing and sensing terminal in a predetermined orientation relative to the container or conduit wall so that the flow of granular material is substantially diverted away from the lower portion of the sensing terminal.

Abstract: In a capacitance type liquid level measurement gauge having an oscillation circuit including a frequency generator, a capacitance and a resistance which is connected in series with the capacitance, the capacitance including a pair of electrode plates submergible in a liquid to be measured, there is provided a further condenser which is connected in series with the capacitance.

Abstract: An indicator is provided for each of a number of preselected conditions and is actuated in response to the occurrence of the corresponding condition. The indicator remains actuated until manually reset even if the triggering condition no longer exists.

Abstract: A sensing and indicator system for monitoring multiple electric heating elements connected in three-phase balanced Y circuits in heat reactivatable adsorbent gas fractionators. The system senses a failure induced imbalance, pinpoints the location of the group with the failure and causes a failure indicating alarm to function. The system operates by a sensing circuit including a discharge bulb sensing the failure induced imbalance and causing a conduction of current through the system resulting in the activation of an alarm and the illumination of the gas discharge bulb indicating which of multiple sets of heating elements has failed.

Abstract: In the particular embodiments described in the specification a device is provided to protect against failure of a switch connected to a load and to give an alarm that the switch has failed. The device includes a circuit in parallel with the switch which contains a transistor and a diode to cause such voltage drop in the circuit as to prevent current flowing through a second diode when the switch is closed. If the switch fails open, the potential at the load side of the switch will drop, and the second diode will allow current to flow to the load through the circuit. The current flow produces a potential difference across the first diode to turn on another transistor to cause an alarm to be given. The device may be used to test such switches without affecting the load controlled by the switch.

Abstract: A battery power indicator for a DC to DC flyback converter is responsive to the current flowing in the secondary winding of the converter's transformer. In one embodiment the power indicator is lighted when the battery is weak but not dead. If the battery is good, the indicator is bypassed and remains off. In a second embodiment, the indicator is lighted to indicate a good battery and when the power capability of the battery drops below a predetermined level, the indicator turns off.

Abstract: Transient change in heat flux due to ultrasmall variation in flow conditions (say from no-flow to flow) within a series of relief flowlines to pinpoint sources of plant upset, is achieved by carefully positioning (in each flowline closely adjacent to an associated relief valve) a transducer-meter for sensing transient heat flux from a selected location completely exterior of the line; and recording in sequence: (i) a base line signal indicative of a no-flow, steady state condition at each selected location along the flowline, and (ii) a transient signal indicative of a flow condition. Both types of signals are generated by a plurality of thermocouples (a thermopile) attached to each flowline in a heat flux sensing relationship that takes into account the type of fluid being monitored and the temperature gradient existing across the relief valve.

Abstract: Transient change in heat flux due to ultrasmall variation in flow conditions (say from NO-FLOW-to-FLOW) within a series of flowlines to pinpoint sources of plant upset is achieved, by carefully positioning a series of M transducer-meters for sensing transient heat flux, each meter being disposed at a selected location completely exterior of a flowline, and recording in sequence at a central control center for each of the M meters at least a transient signal indicative of a FLOW condition. For each meter, signals are generated by a thermopile attached to each flowline in a heat flux sensing relationship. Location takes into account the type of fluid being monitored, and the temperature gradient existing across the relief valve. Recordation of the sensed signals is via a series of M recorders and alarm circuits at the control center.

Abstract: A battery voltage drop alarm circuit comprises a battery voltage drop detecting circuit, an alarm circuit, and an alarm cut off circuit. The battery voltage drop detecting circuit outputs an alarm instruction signal to the alarm circuit when the battery voltage drops to less than a predetermined value, then the alarm circuit generates an alarm sound. The alarm cut off circuit generates an alarm operation cut off signal to the alarm circuit to cut off the alarm operation thereof when the battery forklift performs the auxiliary work.

Abstract: A system for identifying emergency exits in a building includes a strobe light which is tethered at an elevated location with respect to the floor of the building. The strobe light is normally held at the elevated position by an electromagnet, which electromagnet is kept energized as long as a smoke detector connected thereto does not sense a dangerous level of smoke. As soon as the smoke detector detects smoke above a certain threshold level, the electromagnet is deenergized and the strobe light drops to a position suspended just above the floor. The strobe light includes its own battery source which is connected to the strobe light by a switch which closes when the strobe light is dropped. An electric motor is provided to rewind the tether when the smoke detector no longer indicates an emergency situation. By tethering the strobe light, the light can be dropped beneath the smoke level in the building, allowing people crawling along the floor to determine the location of emergency exits.

Abstract: A battery jumper cable system wherein an alarm is provided upon initial misconnection of the system cables to a first-connected battery, or upon subsequent misconnection of one of the system cables to a second-connected battery. The system includes principal conductors for connection to the terminal posts of the batteries, and an auxiliary conductor for connection to the frame or ground terminal of the second-connected battery. An alternative embodiment provides for two auxiliary conductors whereby either end of the cable system can be connected to either battery.

Abstract: A device for indicating the flow of gases includes a vertically extending conduit section in which is disposed a ball. The ball seats on a lower seat at zero or minimum gas flow, and on an upper seat at maximum sensed gas flow. The upper seat is configured to permit essentially unrestricted gas flow when the ball is seated on it.Electrical means are associated with either the bottom seat and/or the top seat and co-acts with the ball to sense either minimum gas flow or maximum gas flow, and generate a signal responsive thereto.

Abstract: A safety plug to an outlet box receptacle, which includes an overcurrent protection device, and engaging devices for engaging the safety plug adapter both to flanged portions of the outlet box face plate and to the electric cord so that it is difficult for a small child to remove the electric cord connecting plug from the adapter, or the adapter from the outlet box receptacle. The adapter may also include a voltage-actuated light-emitting device to indicate when the outlet box receptacle is energized, and a spring-loaded adapter receptacle cover plate.

Abstract: A robust electronic liquid level gauge apparatus, particularly suitable for use with boiler drum water column, comprises simple probe sensors in the water column, differential amplifier sensors, detectors responsive only to the simultaneous presence of a minimum level signal and a certain frequency, and logic circuits continuously processing outputs from four detectors: its associated probe detector, the one below, and the two above.