Abstract: A carpet mat switch system is provided in which a person when stepping on a mat structure will electrically activate a lamp, burglar alarm, program talking clock or any other appliance connected thereto. A manual override is also provided to either turn off an actuating unit in the mat structure or manually operate a switch therein without stepping on the mat structure.

Abstract: The liquid level in a tank is determined by measuring the current supplied to an elctromagnet from which a rod having a specific gravity greater than that of the liquid is suspended in the liquid.

Abstract: A liquid level control in a refrigeration system operates a solenoid valve to maintain the level of liquid refrigerant in a vessel within a range defined by predetermined lower and upper liquid levels, sounds an alarm if the upper level is exceeded and stops a pump if the lower level is violated. The control comprises a float assembly and a switching assembly. The float assembly comprises a float chamber connected to the vessel, a float ball therein, a vertically extending float rod connected to the float ball and movable along a vertical path, and a pair of spaced apart stop members on the float rod disposed within the switching assembly. The switching assembly comprises a switch actuator permanent magnet, having magnet poles at opposite ends, slidably mounted on the float rod between the stop members and movable thereby along the said path.

Abstract: A monitor or sensor for sensing the moisture content of a surrounding medium comprises two electrodes connected in a detector circuit for detecting the impedance between them and producing an output signal proportional to the impedance. At least one of the electrodes is covered by a dielectric coating and the other electrode is positioned to minimize any capacitative effects between the electrodes through the surrounding medium. The detector may comprise a multivibrator with an output frequency controlled by the sensor impedance, and the output signal can be used to control the operation of watering equipment.

Abstract: An improved capacitance bridge type liquid level control system for use in refrigeration applications is disclosed which provides improved apparatus for sealing the probe in its mounting and for insulating same against the condenser reservoir stand pipe in which it is mounted. Improved sealing between the probe and probe body is accomplished through an annular PTFE seal which when compressed pushes inwardly to seal a tubular PTFE insulation against annular ridges in the side of the probe rod proper. The improved probe rod shape also maintains a proper stabilized axial alignment between the probe rod and the probe body.

Abstract: A ground fault interrupter (GFI) circuit is wired to a main circuit breaker panel. A first output of the ground fault interrupter circuit provides electrical current to a solenoid valve that controls the supply of cold water to a conventional hot water heater. The solenoid valve is held in its open position by 110 V. alternating current and is closed by spring biasing means when the current is cut off. The other output of the GFI circuit provides 110 V. alternating current to a leak detector. A leak detecting system directs leakage to a collector wherein the presence of water in the collector completes the circuit between the hot wire and ground of the second outlet. When the circuit is shorted out to ground by the presence of water the GFI circuit is tripped at the main circuit breaker panel and simultaneously cuts off current to the solenoid valve controlling the flow of water to the heater permitting the spring to bias the valve shut and preventing any water damage due to leakage.

Abstract: A combination hybrid float switch comprising float support means, float support means including a top and a bottom and an internal tube, the internal tube being sealed with respect to a liquid encountering the float support means. A float means is slidably positioned about the internal tube, the float means including a magnet means, the float means being responsive to the level of the liquid. A circuit board means is positioned within the internal tube and includes a plurality of magnetic reed switches. The reed switches are mounted upon the circuit board, the plurality including a first enable switch, second pump switch and a third alarm switch. The pump switch and the alarm switch are physically aligned in a parallel position above the enable switch, the enable switch and the alarm switch each being modified with one shortened lead, thereby modifying the reaction to a magnetic field. the modified reeds eliminate an otherwise conventionally act of state.

Abstract: Basement flooding due inter alia, to drain overflow or sump pump failure is a common problem. An apparatus for solving the problem includes a cover for closing a basement floor drain, a tubular casing extending through the cover into the drain, a pair of spaced apart conductors in the casing for completing an electrical circuit when water rises through the open bottom end of the casing to a predetermined level, and a control circuit connected to the conductors and to a solenoid valve in the building water supply pipe for closing the latter, so that no additional water enters the drain to exacerbate an already bad condition. A second pair of spaced apart conductors on the floor of the basement is coupled to the control circuit to give the same response in the presence of floor moisture. An audible alarm is sounded as part of the response to detected water.

Abstract: An immersion detection current interrupter circuit with an electric latch for use in small electrical appliances. A sensor wire is positioned within an appliance to sense current leakage when in contact with a conductive fluid. A relay or solenoid connected to the sensor is positioned between the load leads in a latch circuit. When the sensor detects a leakage current, it causes a two-pole double-throw relay to latch, breaking the load lines beyond the relay. The relay will remain latched until the power cord is unplugged or reset by a switch which opens and closes the power lines. Once the component has latched, the maximum leakage current will be limited by the voltage drop across a diode.

Abstract: A liquid level sensor and controlling assembly disposed and mounted in direct communication with a reservoir of liquid to be monitored and including a float structure connected to an elongated stem formed of magnetic material which is disposed to selectively move, in accordance with the movement of the upper surface level of the liquid between a primary coil and a secondary coil. A constant voltage supplied to the primary coil results in a magnetic flux and a voltage being induced into the secondary coil based upon position of the magnetic material stem relative to the secondary coil thereby determining that the induced voltage in the secondary coil is directly related to the level of the liquid since the position of the magnetic stem within the secondary coil is controlled by the level of liquid within the reservoir.

Abstract: An apparatus for stopping an electrically driven watering system in response to rainfall, said apparatus having a float activating a reed switch which is mounted within a rain-catching cylinder, said read switch then activating a relay switch to interrupt the flow of electricity in the system. Also included is a rigid mounting strap and pivot strap permitting the casing of the apparatus to be conveniently removed and the rain-catching system to be emptied by one standing on the ground.

Abstract: A monitoring assembly (20) which has a plurality of sensors (24) arranged in spaced relationship along a body (23) which may be suspended from a coded multicore cable (25) in a reservoir to monitor liquid levels therein. Each sensor (24) is connected to a respective coded core (43) of the multicore cable (25) such that any sensor (24) may be selectively coupled to remote control apparatus.

Abstract: A shock protection circuit utilizing an immersion detection current interrupter for use in small electrical appliances wherein the combination of a solenoid or a relay plus a sensor will cause an interruption of the power leads of a small appliance and the mechanical latching of the relay or solenoid contacts in an open position when the presence of an electrically conductive fluid is detected. In one embodiment, the sensor remains conductive at a safe level, while in a second embodiment power to the sensor is also interrupted. Both embodiments are immune to electrical noise.

Abstract: Herein is a circuit which is capable of detecting the presence of liquids, especially cryogenic liquids, and whose sensor will not overheat in a vacuum. The circuit parameters, however, can be adjusted to work with any liquid over a wide range of temperatures.

Abstract: A leakage detecting device for electrical appliance is provided with electrodes (17) for detecting a state in which an electrical appliance such as a hair dryer is submerged in water. When the electrodes (17) are in a short-circuited state, relay means (3) is driven to open a contact (7). As a result, supply of the power supply voltage from a commercial power source (1) to the loads such as a motor (15), a heater (16) and the like is stopped so that an accident due to leakage can be prevented in such cases as a case in which the electrical appliance has been dropped into the water.

Abstract: The liquid tank comprises a container (1) containing a level gauge (3), an element (9) indicating the position of the gauge (3) and located outside the container (1), and a filling duct (2) for the container (1) fitted with an electro-magnetic sluice gate (10), a container (1) with a float (3) which modifies the resistance (9) as a function of its level. The value of the resistance (9) is monitored as a function of the time starting from the start of the filling operation so as to detect any fault inside the container (1).

Abstract: A portable electric hair dryer includes an electric heater and blower forming a load circuit energized from a pair of power feeder lines connected to a source of AC power. A zero phase-sequence current transformer is electrically coupled to the power feed lines between the connection thereof to the power source and the load circuit to serve as a current leakage detector. An electricaly conductive heater enclosure disposed within the housing of the hair dryer receives the heater and is electrically isolated from the power feed line serving as the hot line. The heater enclosure is electrically connected to the power feeder line serving as the neutral line by a ground wire extending between the heater enclosure and the point at which the zero phase-sequencing transformer is coupled to the power feeder lines to define a leakage current path between the hot line and the heater enclosure should the hair dryer be dropped in water.

Abstract: A moisture sensor having an oscillator circuit with its output frequency directly proportional to moisture percentage present in the substance of interest, such as soil. The oscillator circuit includes two spaced plates in the substance which function as a capacitor. The frequency of the oscillations changes as the capacitance between the plates changes due to the moisture present between the plates. The sensor is particularly adapted for use as a soil moisture detector and provides indications of moisture percentage or end points such as wet or dry conditions.

Abstract: A detector for sensing the presence of polar fluids includes a pair of detection probes and a circuit for providing an oscillating voltage across the probes. A power supply for the detector includes a transformer with a split secondary, with at least one secondary having a floating ground. One of the probes is connected to the floating ground. The other probe is connected to the input of a fluid detection logic circuit. The input is applied to an inverter having an activation threshold of approximately six volts. The resulting activation threshold of the detector circuit is sufficiently low to be activated by the oscillating voltage so as to produce a polar fluid output signal when the probes are immersed in a polar fluid, but sufficiently high so as not to be affected by stray voltages induced in the probes by conventional power lines, such as 120 VAC lines, contacting the polar fluid.

Abstract: A moisture sensor having an oscillator circuit with its output frequency directly proportional to moisture percentage present in the substance of interest. The oscillator circuit includes two spaced plates in the substance and functioning as a capacitor. The frequency of the oscillations changes as the capacitance between the plates changes due to the moisture present between the plates. The sensor is particularly adapted for use as a soil moisture detector and provides indications of wet or dry conditions.

Abstract: A temperature controller with a remote sensor having a high temperature cutoff with circuit means to prevent operation of the unit if tampered with to bypass a safety function. A remote sensor has a thermal fuse and diode feeding a pulsating D.C. voltage to a control circuit having a capacitor and an impedance means to which pulsating D.C. is fed. If the sensor unit is bypassed the thermal fuse in the controller burns out to render the controller inoperative.

Abstract: An electromagnetically actuatable probe is inserted in a vessel containing a body of liquid and in which high pressure, high temperature, corrosive, or other hostile conditions exist. Pulses are transmitted to the probe within a predetermined range of frequencies which include the normal resonant frequency of the probe. Return signals are generated by the probe between the times the transmitted pulses are sent. These return pulses are processed to produce signals which are a function of the level of the liquid that are then employed to control the discharge of the liquid or used by another utilization circuit.

Abstract: The invention pertains to an electric device which can be started by immersion in a liquid by way of two electrodes. It includes a first circuit having two electrodes in series with a first voltage source and the coil of a first relay, for controlling a second circuit having in series a second voltage source, a second relay and the contact of the first relay. The second circuit also is connected to use terminals for an external load, the voltage at the use terminals of the circuit being equal to the sum of the voltages from the first and second voltage sources. The device can be applied to power submersible buoys and to detect the presence of a liquid.

Abstract: Apparatus for monitoring and controlling the level of fluid in a reservoir. The apparatus utilizes a fluid sensing probe to monitor the level of fluid in a reservoir and can generally be installed in an existing fluid reservoir without requiring structural modification of the reservoir. The apparatus, in determining the level of fluid in a reservoir, compensates for swells and other surface undulations which mask the true fluid level in the reservoir.

Abstract: A liquid level control device for monitoring the level of water in a steam generating tank between predetermined upper, intermediate, and lower levels, with the tank equipped with a valve for introducing water into the tank and heat energy valve means to generate steam to the water, comprising: a glass gauge tube adapted to be vertically mounted exteriorally of the tank; a top and bottom cover covering the ends of the glass gauge tube, with a bottom cover including an opening for communicating with a liquid in the tank and the top cover including an opening for communicating with steam generated in the tank; upper and lower magnetic float means mounted co-axially within the glass gauge tubes; the upper magnetic float means including means to activate the valve when the water is the region of the predetermined intermediate level so as to introduce water into the tank until the water is in the region of the predetermined upper level, and to deactivate the valve and stop the introduction of water when the water

Abstract: A circuit for controlling the level of a liquid in a tank between predetermined limits is disclosed. A low and high probe are provided, each connected in the tank at the desired limit levels, and each connected to a comparator associated therewith. The output of each of the comparators are connected as inputs to an OR gate, which provides the control signal for activating a pump to pump liquid from the tank, and further provides a latching signal to the lower limit comparator, to keep that comparator latched in an off position until the upper limit comparator is triggered by liquid coming into contact with the upper limit probe.

Abstract: An energy transfer network is used to ensure reliable operation of a low water sensing system for a boiler. The energy transfer network provides a sufficient time interval to make sure that wave action and boiling within the boiler do not simulate the loss of water. The energy transfer network is structured to be discharged in the event water actually drops below an appropriate level. The energy transfer network provides for the continuous presence of water so that boiling action does not simulate an artificially high (presence of) water level.

Abstract: A pair of PTC elements, preferably of the barium titanate variety, are mounted in a container to sense liquid level, for example oil level in an engine crankcase. The elements have the same resistance, mass and switching point but different thermal loss coefficients which have one value in air and another in liquid. In one embodiment, the elements are both positioned at the set liquid level and are electrically energized at the same moment. When the elements are in liquid, one of them will heat to the switch point before the other and change to a much higher resistance. When the elements are in air, the other element reaches the switch point first. When the elements are connected in series across a power source, the switching causes the circuit to latch in that state even though the liquid level condition changes. The junction of the elements provides a convenient signal output indicating liquid level. In a second embodiment, one PTC element is at the set liquid level and the other is in air above that level.

Abstract: A stepper for use between a transducer subjected to variable pressure, heat or liquid level for converting the continuous output signal of the transducer with all of its variations, both of significant magnitude and those of insignificant importance, into a continuous stepped output signal that increases or decreases the current to a transducer responsive control unit, particularly a servo amplifier, which stepped signal eliminates all minor and unimportant fluctuations from the output current from the transducer. The stepper also includes a sequence of voltage regulators such as potentiometers in the circuits between the stepper and the servo amplifier by means of which the magnitude of the current flow of each step to the servo amplifier may be adjusted or programmed with respect to one another. It is particularly useful in the regulation of flow control valves in water distribution and sewage disposal systems, but its application to steam boilers is also disclosed and described.

Abstract: A non-resettable water actuated circuit interrupting means for use with a portable electric appliance such as a hair dryer to provide protection for the user against injury in the event that the appliance is accidentally dropped in water or otherwise develops leakage current. Both sides of the line are fused and circuit means are provided which respond to leakage current in the appliance to provide separate circuits to blow out each of the fuses.

Abstract: A device to control a temperature variable-resistive type oil fluid level sensor in vehicles. The device employs constant current excitation under control of a relay to maximize the sensor's response and employs a shut-off feature to protect the sensor from overheating.

Abstract: Means for continuously shut-down operation of and enclosed motor-compressor unit for refrigeration or heat pump service when the refrigerant-oil mixture therein reaches a predetermined degree of contamination by conductive particles comprises the provision of a normally closed switch in the motor energizing circuit, a relay which when energized opens the switch, in immersing a pair of spaced electrodes in the mixture, in connecting the electrodes and a capacitor in series across a D.C. power source, in connecting a unidirectional solid state switch and the relay in parallel with the electrodes and capacitor and in providing voltage responsive gating means for turning on the switch in response to a predetermined charge on the capacitor, and in the provision of a normally open fusible switch responsive to fuse and close in response to a predetermined high motor temperature and through relay means opens a second normally closed switch in the motor energizing circuit.

Abstract: A level control apparatus is disclosed for controlling a liquid level between a maximum and a minimum. An elastic circuit generates a reference pulse which receives the pulse and triggers the generation of first and second reference pulses. The first reference pulse has a width which corresponds to the function of the maximum level of liquid and the second reference pulse has a width which corresponds to the function of the minimum of liquid. A capacitance probe supplies an output to a level sensing means which generates an output control pulse which varies in time with respect to the liquid level.

Abstract: Improved apparatus for providing both a liquid level control and a low water cut-off for boilers and the like, having only a single probe and a single relay.

Abstract: Valve closure means having a low rpm motor with a shaft coupled to the stem of a shutoff valve located in the supply line of a water heater or like device; said motor having support means attaching to the supply line is energized to rotate said shutoff valve to a closed position when the tank of said water heater or like device ruptures, thereby terminating flow in the supply line.

Abstract: A power control relay with a solid state switching device being arranged to control the current to the coil of the relay in a series circuit therewith can be operated safely and reliably in manufacturing environments by control thereof with a floating voltage developed by the secondary of a low voltage transformer with one side of the secondary connected to the gate of the solid state switching device through a diode and the opposite side of the secondary being controlled by a resistive probe circuit, which when grounded, will cause a voltage to be impressed on the gate that will cause the switching device to trigger thereby operating the relay due to the differential impedance developed in the floating voltage circuit arrangement.

Abstract: A driver for the excitation coil in the electromagnet of an electromagnetic flowmeter, wherein the fluid to be metered is conducted through a flow tube to intersect the transverse magnetic flux field created by the electromagnet. The driver includes an a-c line rectifier whose output is coupled to the coil by a pair of switching transistors, the control electrodes of which are connected to the output of a comparator having first and second input terminals. Applied to the first terminal of the comparator is an alternating square wave voltage, each cycle of which has a positive and a negative gating pulse such that the transistors are alternately actuated, the arrangement being such that the rectified output is applied by the transistors to the coil with a polarity which is alternately reversed.

Abstract: There is provided a method and apparatus for measuring the moisture content of materials, e.g., tobacco. In cases where the material flow is intermittent, the maximum moisture content of the last sample is indicated and held either for a predetermined time or until the moisture content of the next sample is determined.

Abstract: An overflow control system for use with home appliances such as washing machines, incorporating conventional stand pipe which receives the outlet conduit from the appliance, the stand pipe being provided with an attachment having a displacement, conductivity or a pressure sensor installed for sensing the height of liquids in the stand pipe. This stand pipe may be vertically connected to the sewage line outlet found in a home and the signals from the sensors may be used to shut off the power to the appliance and to excite an alarm. Connected in parallel with the sensors may be a moisture sensor deployed under the appliance which again shuts the power off whenever the machine is inadvertently filled beyond its limits or when leakage occurs.

Abstract: A pneumatic valve system for sealing off the flow of a liquid at the intersection of two pipes, one of the pipes being vertically disposed with respect to the other pipe. A sensing probe senses liquid at a pre-established height in the vertically disposed height which signals a control system to activate the pneumatic valve system. An expandable, inflatable bladder is positioned from the vertically disposed pipe into the second pipe and is inflated, thereby sealing off the flow of liquid past the bladder. When normal fluid flow is to return, the bladder is deflated and positioned back into its original position within the vertically disposed pipe.

Abstract: An overflow control system for use with home appliances such as washing machines, incorporating conventional stand pipe which receives the outlet conduit from the appliance, the stand pipe being provided with an attachment having a displacement, conductivity or a pressure sensor installed for sensing the height of liquids in the stand pipe. This stand pipe may be vertically connected to the sewage line outlet found in a home and the signals from the sensors may be used to shut off the power to the appliance and to excite an alarm. Connected in parallel with the sensors may be a moisture sensor deployed under the appliance which again shuts the power off whenever the machine is inadvertently filled beyond its limits or when leakage occurs.

Abstract: An apparatus for measuring the level, volume or rate of flow of an electrically conductive fluid, such as water, includes a reference conductor connected to a reference potential and a plurality of additional, vertically spaced conductors affixed to an insulating surface. The reference conductor is normally placed at the lowest point of the liquid container whereas the other conductors are positioned within the liquid container at various points above the reference conductor. When the level of the liquid is above the position of one or more of the additional conductors, the liquid effects an electrical conduction path between the conductors below the liqid level and the reference conductor and thus with the reference potential. The conductors are connected through a logic circuit to a plurality of display elements, which are selectively actuated to provide an indication of the level of the liquid corresponding to the uppermost conductor covered by the liquid and thereby connected to the reference potential.

Abstract: An electronic sensor package includes at least six sensor-amplifier circuits each adapted to be electrically connected to a different condition-responsive device and each electrically connected directly to a relay for energizing the relay, each of the relays being electrically connected to at least two of the sensor-amplifier circuits, whereby the number of relays to which the sensor amplifier circuits are connected is no more than half the number of sensor-amplifier circuits. The relays are electrically connected to a timing circuit electrically connected to signalling or controlling devices.

Abstract: An apparatus for automatically controlling a watering system in response to a comparison of an ambient condition with a time-varying reference level having an adjustable maximum value is disclosed. The invention includes an electrical circuit for monitoring and sensing the magnitude of the ambient condition and for converting the sensed magnitude into a proportional electrical signal. The invention further includes a first timer circuit for generating a triggering signal when the time-varying reference level exceeds the magnitude of the proportional electrical signal. This triggering signal is applied to a second timer circuit which actuates the watering system for a predetermined period of time in response to the triggering signal.

Abstract: An automatic flood control valve apparatus having a normally open valve, in combination with a latching relay for closing the valve, which latches the valve in a closed position when the relay is energized and until it is manually reset, and a single transistor sensor circuit for energizing the relay in response to a flood. A power supply circuit is also disclosed.

Abstract: An automatic water safety valve assembly having sensors adapted to be placed in various locations on the floors of a building so that an expandable element in each of the sensors having an electrically conductive plate expands when wetted to operate a circuit which causes the water safety valve to close and shut off the main water line to the building. The valve, when activated, also operates a power interrupter which deactivates the connections to the device from the AC power source.

Abstract: A resistive controller suitable for sensing a variable electrical resistance indicative of a characteristic of a substance and for connecting an external electrical device to a source of electrical power when the measured electrical resistance reaches a predetermined level. The resistive controller includes a timer circuit which is activated when the measured electrical resistance reaches the predetermined value and which, in one embodiment, provides an adjustable time period, upon the expiration of which, the external electrical device is disconnected from the source of electrical power. In another embodiment, the timer circuit provides an adjustable time period, upon the expiration of which, the external electrical device is connected to the source of electrical power.

Abstract: The environmental signal switch is an electronic device primarily for automotive use which is responsive to the absence of daylight and moisture. The device is designed to send a signal to selected electronic devices, namely the gates of scr's to activateselected electrically operated devices. The switch is designed to send a signal to one or more scr gates only, in response to moisture, and send signals to the same said scr gates, and one or more additional scr gates in response to the absence of daylight. The device as used in automotive application is to allow for the closing of windows and roof panel in response to rain regardless to whether keys are left in the ignition. In response to the absence of daylight, said windows, roof panel, and door locks are activated, provided said keys are removed from the ignition. The switch can activate the said electrical devices directly or indirectly, by said means of activating the gates of said scr's. The said scr's can be part of an environmental security system.

Abstract: The present invention refers to a system of protection against electric current short circuits and fulminations, apt to be applied on any installation comprising an electric apparatus and a polyphase feeding cable connecting said apparatus to a socket through connection means. According to the invention, the installation comprises a screening of the electric apparatus and/or of the feeding cable, formed by a pair of spaced wire nets being electrically insulated one from the other, a two-phase auxiliary electric line with each phase connected to one of said wire nets, and a cutout circuit associated to said connection means for disconnecting the electric feeding in response to a short circuit between said two wire nets.

Abstract: A system for sensing and controlling the level of fluent material in a reservoir or other receptacle. In electrically conducting materials levels are sensed by low voltage direct current conduction between electrode pairs placed at desired "high" and "low" control levels which send D.C. digital logic sensing signals over connecting wires to very high resistance "high" and "low" inputs of a digital logic signal processing circuit, while nonconducting material levels are sensed by suitable transducers which upon immersion can send D.C. digital logic signals. The digital signal processing circuit receives the sensor signals and provides a digital output signal or absence thereof, depending on the relative state and sequence of the sensing signals and transmits a digital output signal to a solid state relay which controls the power of flow control means to maintain desired levels of the fluent material.