Abstract: A new and novel system for protecting people and property against electrical shock. It includes a number of preferred and other embodiments which have this as their goal, but which represent a number of distinctive and novel approaches to solving prior art problems. By way of example only, and without limiting the scope of this invention, these approaches include novel immersion detecting circuits, broken wire test circuits, electromechanical circuit breaking including coil/plunger arrangements, and relay circuit breaking mechanisms cooperative with associated circuitry, all of which are able to be incorporated as a system wholly within the load (appliance) and its associated cord set (including a "plug").

Abstract: The electronic switching device serves to control the connection of a load to a voltage source by a switch which is controlled in a first operating mode directly by a binary signal furnished by a signal processing circuit and in a second operating mode inverted. The switching device has three terminals, of which the first permanently remains connected to a first terminal of the voltage source and to a first terminal of the load, whilst of the other two switching device terminals the one is connected to the second terminal of the voltage source and the other to the second terminal of the load. The switching device is configured so that it can be changed over from the one operating mode into the other by interchanging the connections between these two other switching device terminals and the second terminals of the voltage source and of the load, respectively.

Abstract: An electrical switch sensitive to an externally applied inertial and gravitational force, having an enclosure with a closed space; a conductive fluid filing a first portion of the space and a non-conductive medium filling a second portion of the space, the conductive fluid and the non-conductive medium having differing densities; at least two electrodes in communication with the space; an electrical circuit coupled the contacts and having electrical connections for connection with a power source and a load, having a semiconductor switching device, which is responsive to a current through the contacts, a current through the contacts causing the semiconductor switching device to change in conductivity. An externally applied force, e.g., gravity or inertial force, causes the conductive fluid to move within the enclosure with respect to the contacts, altering a current through the contacts, and thereby changing a conducting state of the semiconductor switching device.

Abstract: A system for temporarily preserving the signal-flow to a device when a signal switch has been tripped. The system includes a time-delay relay connected in parallel with the switch. When the switch is tripped, breaking the signal-flow through the switch, the time-delay relay is energized for a set period of time to maintain the signal-flow to the device. The condition which will trip the switch and the amount of time during which the time-delay relay will preserve signal-flow will vary depending upon the particular application. During the set period of time, the switch has an opportunity to recover from the condition which originally tripped the switch and resume signal flow through the switch. If the switch tripping condition persists for longer than the set period, then signal-flow to the device is interrupted after the set period of time expires. The system minimizes unnecessary interruptions in signal-flow when the switch has been accidentally or unintentionally tripped.

Abstract: An apparatus for detecting the flow direction of a fluid from an apparatus or between two apparatuses such as a biohoods, fume cabinets, or filters. The device includes a conduit horizontal plane and adapted to receive the fluid. A detecting element is disposed within the conduit and is movable in the direction of fluid flow, the detecting element being in direct contact with the fluid. A sensing element may be coupled to the conduit for determining when the detecting element reaches a predetermined position within the conduit. The circuitry coupled to the sensing element enables selection of a desired flow direction and actuates an alarm when the detected flow direction is other than the one selected.

Abstract: An overflow protection shut-off device for use with a water heater for shutting off a supply of water to the water heater when a leaking or an overflow condition occurs, the device including a valve mechanism coupleable to an input water line of a water heater and having an opened orientation for allowing flow of water within the input line and a closed orientation for preventing such flow; a water sensing mechanism positionable at a location proximal to the water heater for providing a signal when it is placed in contact with water when the water heater experiences the leaking or the overflow condition; and a switching mechanism coupled to the valve mechanism and the water sensing mechanism and with the switching mechanism being responsive to receipt of the signal from the water sensing mechanism for placing the valve mechanism in the closed orientation.

Abstract: Paint flow control interface circuitry for passing electrical signals across a paint booth barrier including a feedback signal indicating a paint flow parameter from a parameter transducer within the paint booth, includes passive resistive intrinsically safe barrier circuit elements coupled with buffer circuitry for minimizing the voltage drop across the interface circuitry. Light filtering of the buffer circuitry output signal with minimum filter lag yields an accurate indication of the paint flow parameter with high signal to noise ratio and minimum signal lag, for application in closed-loop paint flow control. Additional transducer voltage supply signal feedback provides for closed-loop voltage supply control across the interface circuit.

Abstract: The present invention relates to a switch device having a sensor for effecting a detection process such as a confirming the operation of an ejector or the like, confirming the existence of an object fed by a suction pad, or confirming the attracted state of an object fed by the suction pad. The invention further relates to a control device-to-sensor wiring structure which is electrically connected to the switch device. The switch device can be reduced in size and weight by detachably positioning a setting section, having a controlling means and a displaying means, on a body of the switch device and removing the setting section as required. Further, the wiring structure makes it possible to simplify wiring and avoid the possibility of miswiring, by eliminating the need for a power line to be connected to each sensor.

Abstract: The present invention teaches a new and novel system for protecting people and property against electrical shock. The invention includes a number of preferred and other embodiments which have this as their goal, but which represent a number of distinctive and novel approaches to solving prior art problems. By way of example only, and without limiting the scope of this invention, these approaches include novel immersion detecting circuits, broken wire test circuits, electromechanical circuit breaking means including coil/plunger arrangements, and relay circuit breaking mechanisms cooperative with associated circuitry, all of which are able to be incorporated as a system wholly within the load (appliance) and its associated cord set (including a "plug").

Abstract: An automatic pump control for a pump such as a marine vessel bilge pump uses solid state components and has no moving parts. A first integrated logic device activates an FET transistor and completes a circuit which turns the pump on when the water reaches a predetermined high level and in association with an interconnected second integrated logic device keeps the pump on until the water subsequently reaches a predetermined low level. The control can be manually operated and includes circuitry to activate a high water alarm. The switch housing is molded in a manner which permits mounting directly to the pump.

Abstract: A sewage grinder pump system for use in moving sewage, having a vertically oriented cylindrical pump motor housing, a bottom plate affixed to and closing the pump motor housing, a motor supported by the bottom plate within the pump motor housing, the motor having a shaft extending through an opening in the bottom plate, a grinder pump supported to a lower end of the bottom plate and connected to the motor shaft, a closure member affixed to the pump motor housing top end and having a level detector receiving portion providing a liquid level detector opening therein externally of the pump motor housing, an elongated liquid level detector having an upper end received within the liquid level detector opening, and a circuit connecting the liquid level detector to control the motor to thereby drive the grinder pump in response to detected liquid level.

Abstract: A portable power supply system utilizes a foot controller and a lightweight, sealed electric motor assembly which attaches to any International Standard E-Coupling handpiece. The foot controller is adaptable for use with either an AC/DC adaptor or a rechargeable battery. A coaxial cable connects the variable voltage supply from the foot controller to the low voltage, DC motor assembly. The motor assembly is sterilizable, lightweight, and quiet, making it ideal for use by dentists, oral or orthopedic surgeons, laboratory technicians, or anyone else desiring an economical, portable power supply for handpieces.

Abstract: A device for control and monitoring of pressure in a system combines a conventional three pole pressure switch with the following additional features: (1) a lock mechanism with three influencing input factors and a single resulting output contact action, (2) a three pole thermal release device as one of the input factors, and (3) a remote control tripping device as another input factor, all integrated into a single, compact, modular unit. The thermal release device comprises a plurality of bimetals which sense electrical flow passing through the device, and which are mechanically connected to a locking mechanism to shut off current if the electrical flow reaches a predetermined maximum. If any of the three inputs activates the locking mechanism, the device must be reset by an operator.

Abstract: A level switch includes an operational amplifier, provided with positive and negative feedback, and a sensor, together forming an astable multivibrator. The oscillation onset and frequency of the multivibrator depend on the surface level of controlled material. The sensor includes a dielectric body on which, starting from its fastening end, a grounded opposite electrode and a screening electrode, connected to the amplifier output, are mounted. A ring plate connected to the inverting amplifier input is incorporated coaxially in the dielectric body. The level switch need not be adjusted when the controlled material is changed, although materials may have quite different electrical properties and may stick to the sensor.

Abstract: A leak detector and circuit interrupter for detecting the presence of a liquid in the base of a dispenser containment box and interrupting the supply of electrical power when such liquid is detected is disclosed. There is a user enableable circuit for selectively enabling the pump and an override circuit which is operable when enabled to disable the user enableable circuit. An optical liquid sensing probe is positioned near the bottom of the containment box with optical coupling to the override circuit. The optical probe is coupled to a light emitting diode, a photosensitive transistor, and includes a light path with at least one total internal reflection surface normally coupling the light emitting diode and the photosensitive transistor. The probe normally maintains the override circuit in an ineffective state, but, when the light path is interrupted by an accumulation of liquid in the bottom of the containment box, changes state thereby enabling the override circuit and disabling the pump.

Abstract: A capacitance point level switch includes a probe adapted to be disposed in a material containing vessel, the material having a capacitance value dependent upon its level in the vessel. An oscillator circuit develops a periodic signal at a select frequency. A reference network is driven by the oscillator and includes a reference capacitance for developing a periodic reference signal at the select frequency and phase displaced responsive to the reference capacitance. A probe network is driven by the oscillator and is connected to the probe to include the capacitance of the material for developing a periodic probe signal at the select frequency and phase displaced responsive to capacitance of the material. An output circuit is connected to the reference network and the probe network for developing a discrete output assuming a first or a second state according to the relative phase displacement of the periodic reference signal and the periodic probe signal.

Abstract: An electric circuit substrate apparatus having a micro-processor for a control of a device is comprised of a substrate, an electric circuit arranged on the substrate and including a rectifier, an electrolysis condenser, a detecting device for detecting the voltage of a current outputted from the electrolysis condenser and the micro-processor which is set to stop the control of the device upon receipt of a signal from the detecting device, and an enclosing device for immersing therein the substrate and the electric circuit, except for a portion of electrolysis condenser, in order that the immersed elements are interrupted from the ambient air.

Abstract: An apparatus has a liquid level sender providing a sender output signal which varies with a measure of a liquid and which varies with a slosh of the liquid. A main control circuit couples and decouples the sender output signal to a process circuit, the process circuit provides an output signal to a liquid level indicator. Two monitor circuits monitor the output of the process circuit and provide a control signal to the main control circuit if the sender output signal varies from the output of the process circuit by more than a predetermined amount. A switch within the main control circuit decouples the sender output signal from the process circuit in response to the control signal. Sample circuitry within the process circuit drives the output of the process circuit in accordance with a sampled signal when the sender out signal is decoupled from the process circuit.

Abstract: Improved timing circuits (205), charge dispensing circuits (213,215), and methods and systems (100) for operation of warewashing equipment. According to one aspect of the invention the system operates on both door and conveyor types of machines. The system dispenses both an initial charge amount and a dose amount during normal operations. In door types of systems, only a single power/signal connection (109) needs to be made to the dispensing system; in one embodiment the warewash rinse power connection. Further, the system can dispense detergent at an interval of greater than once per cycle or operation.

Abstract: An apparatus for detecting the flow direction of a fluid between two enclosed spaces, such as hospital rooms, includes a conduit extending along a horizontal plane and adapted to receive the fluid. A detecting element is disposed within the conduit and movable in the direction of fluid flow, the detecting element being in direct contact with the fluid. A sensing element may be coupled to the conduit for determining when the detecting element reaches a predetermined position within the conduit. The circuitry coupled to the sensing element enables selection of a desired flow direction and actuates an alarm when the detected flow direction is other than the one selected.

Abstract: The invention relates to a liquid sensing switch for use primarily in sensing the bilge water level aboard a boat. The switch is designed with a high input impedance and a high trigger sensitivity, so that the presence of a liquid may be detected by using a remotely located single wire probe. The probe is able to sense immersion into low conductivity liquids or into liquids where no hardwired ground is provided, such as within fiberglass boat hulls. In order to prevent false triggering and cyclic operation of the bilge pump, the liquid sensing switch provides a time delay before it is activated, as well as a further time delay before being deactivated.

Abstract: An electronic device for modifying the calibration of the electronic control system of a modern electronic transmission. An analog processor monitors an electrical current indicating the internal line hydraulic fluid pressure of the transmission and the throttle output of an engine associated with the transmission to detect deficiencies in the internal line hydraulic fluid pressure of the transmission. Further, upon the detection of deficiencies in the internal line hydraulic fluid pressure, the analog processor alters the electronic feedback between the electronic control system and an electronic pressure valve responsible for regulating the internal line hydraulic fluid pressure to increase the internal line hydraulic fluid pressure.

Abstract: A fluid drop detecting reservoir tank has a float with a magnet which moves down in accordance with a drop in the level of fluid in a reservoir tank. The magnet closes a magnetically operated switch when the fluid reaches a predetermined level so that a predetermined drop in the level of the fluid is detected. The fluid drop detecting reservoir tank is provided with a mount casing for receiving therein a switch casing in which the switch is encased. The reservoir tank is provided with a retainer mechanism arranged between the mount casing and the switch casing for holding the switch casing in the mount casing so as to locate the switch below the magnet and preventing the switch casing from being withdrawn from the mount casing.

Abstract: A transient signal suppressor (10) for use in a controls system which is adapted to respond to a change in a physical parameter whenever it crosses a predetermined threshold value in a selected direction of increasing or decreasing values with respect to the threshold value and is sustained for a selected discrete time interval. The suppressor (10) includes a sensor transducer (12) for sensing the physical parameter and generating an electrical input signal whenever the sensed physical parameter crosses the threshold level in the selected direction. A manually operated switch (30A, 30B) is provided for adapting the suppressor to produce an output drive signal whenever the physical parameter crosses the threshold value in the selected direction of increasing or decreasing values.

Abstract: An apparatus for detecting the flow direction of a fluid between two enclosed spaces, such as hospital rooms, includes a conduit extending along a horizontal plane and adapted to receive the fluid. A detecting element is disposed within the conduit and movable in the direction of fluid flow, the detecting element being in direct contact with the fluid. A sensing element is coupled to the conduit for determining when the detecting element reaches a predetermined position within the conduit. Circuitry coupled to the sensing element, enables selection of a desired flow direction and actuates an alarm when the detected flow direction is other than the one selected.

Abstract: A fluid level responsive switch apparatus used in a tank to monitor fluid level in the tank. The apparatus has a float buoy attached to a tilt switch containing three conductors activated by a conductive sphere. The first conductor activates the fluid controller for restoring fluid to the tank when the conductive sphere is in a low fluid level position, the second conductor delays the switching between the activating and deactivating conductors when the conductive sphere is in an intermediate level position and the third conductor deactivates the controller when the conductive sphere is in a high fluid level position.

Abstract: An oil and water separator for separating oil from water collected in a bilge of a boat prior to discharging the water overboard. A reservoir is provided for receiving the mixture of oil and water from the bilge. The oil separates from the water and floats on top of the water. When only water is positioned between a pair of spaced electrical probes carried in the reservoir, such causes a drain valve to be opened to drain the water from the reservoir. As the water is drained from the reservoir, the oil floating on top of the water will come between the probes and close the valve, stopping the draining of water from the bottom of the reservoir. A mixture of oil and water is pumped from a tank carried in the bilge at an intermittent rate so that the mixture is allowed sufficient time to separate in the reservoir.

Abstract: A synchronizing circuit includes two switches for synchronizing the feeding of documents of a document feeder to the insert path of an insertion machine which is operative in accordance with a predetermined machine cycle to establish a given level of vacuum in a vacuum lines. The first switch closes in response to a given level of vacuum in the vacuum line and a rotary magnet driven by the insertion machine causes the second switch to close and then open at given machine cycles. The second switch and the first switch are in series with the document feeder; and, the second switch is operative to be closed and be held closed by the rotary magnet so that the document feeder is operative only upon the occurrence of both a given level of vacuum in the vacuum line and the predetermined proximity of the rotary magnet to the second switch.

Abstract: An automatic sensor system for detecting and adjusting a level of contents held within a reservoir is disclosed. The system has a sensor probe having a probe housing with opposing ends, an interior cavity that opens through one housing end, and a constantly open air vent aperture piercing the housing proximate the other housing end, included within the housing are lower and upper level detection contacts that communicate information about the detected level to a circuit that signals for a contents delivery source to send additional contents when needed.

Abstract: A system and probe for indicating the level of material in a vessel as a function of material capacitance comprising a resonant circuit including a capacitance probe adapted to be disposed in a vessel so as to be responsive to variations in capacitance as a function of material level. An rf oscillator has an output coupled to the resonant circuit and to a phase detector for detecting variations in phase angle as a function of probe capacitance. Level detection circuitry is responsive to an output of the phase detector and to a reference signal indicative of a predetermined level of material for indicating material level as a function of a difference between capacitance at the probe and the reference signal. In the preferred embodiments of the invention disclosed, an automatic calibration circuit adjusts the resonance characteristics of the parallel resonant circuit of the reference signal indicative of a predetermined reference material level.

Abstract: A control switch for controlling the operation of an overhead irrigation system based upon the moisture level of the ground in an area to be irrigated. The control switch includes first and second moisture detection probes positioned at first and second underground locations in the area to be irrigated, which, upon detection that the soil is dry, place a positive conductive charge on the switch, thereby turning on the irrigation equipment. Upon detection that the soil is wet, the probes remove the conductive charge, thereby turning off the irrigation equipment. The control switch provides varying degrees of sensitivity to soil moisture, and varying time delays in turning the switch on when the soil is dry, and in turning the switch off when the soil is wet. A pulsing current protection circuit permits a positive DC signal taken from an AC triac to turn on the triac when both the AC and DC portions of the control switch share a common ground.

Abstract: A control circuit for a sump pump or other pump that controls the liquid level in a vessel. The liquid is maintained between upper and lower levels defined by probes in the vessel. The probes are associated with comparators and connect with one comparator input. The upper limit comparator connects with the gate of an SCR which supplies current to the lower limit comparator and also to a relay which controls the on/off condition of the pump. The output of the lower limit comparator controls a switching transistor which is arranged in a series circuit with the SCR and relay coil. Once the SCR is conductive, it is latched in the conductive state until the transistor is made nonconductive by the lower limit comparator. In a sump pump application, latching of the SCR allows the pump to remain activated after the liquid level is reduced below the upper probe.

Abstract: A liquid activated control switch for detecting the presence of an excessive accumulation of low ionic strength liquids in an air refrigeration system and for controlling the operation of the air refrigeration system based upon the detection of the accumulated liquid which includes first and second liquid detection probes. When the liquid detection probes detect an excessive accumulation of liquid, the air refrigeration system is disconnected. After the excessive accumulation of liquid has been removed, the air refrigeration system remains disconnected until the switch is reset. Alternative embodiments of the liquid activated control switch prevent sloshing liquid in the vicinity of the probes from rapidly turning the switch on and off, by providing varying degrees of sensitivity to accumulated liquid. Time delays are provided in turning off the air refrigeration system when liquid is detected by the probes, and in turning on the system when liquid is no longer detected.

Abstract: A new and novel system for protecting people and property against electrical shock. It includes a number of preferred and other embodiments which have this as their goal, but which represent a number of distinctive and novel approaches to solving prior art problems. By way of example only, and without limiting the scope of this invention, these approaches include novel immersion detecting circuits, broken wire test circuits, electromechanical circuit breaking means including coil/plunger arrangements, and relay circuit breaking mechanisms cooperative with associated circuitry, all of which are able to be incorporated as a system wholly within the load (appliance) and its associated cord set (including a "plug").

Abstract: The present invention teaches a new and novel system for protecting people and property against electrical shock. The invention includes a number of preferred and other embodiments which have this as their goal, but which represent a number of distinctive and novel approaches to solving prior art problems. By way of example only and without limiting the scope of this invention, these approaches include novel immersion detecting circuits, broken wire test circuits, electromechanical circuit breaking means including coil/plunger arrangements, and relay circuit breaking mechanisms cooperative with associated circuitry, all of which are able to be incorporated as a system wholly within the load (appliance) and its associated cord set (including a "plug").

Abstract: A system for indicating level of material that includes first and second probes disposed for operative coupling with material whose level is to be sensed. First and second electrical input circuits are respectively coupled to the probes and provide first and second signals. First and second electrical output circuits provide respective indications of material level by operating relay switches. A latch circuit has inputs that receive the respective first and second signals, and an output that changes state only when both first and second signals change state. The output circuits are selectively connected by jumpers either to the associated input circuit or to the latch output.

Abstract: An internal pressure explosion-proof system by which an electric motor or the like is not rendered operative until after gas in an airtight vessel is replaced with certainty by protective gas. The internal pressure explosion-proof system includes a gas flow detector provided in an exhaust pipe for detecting an amount of protective gas exhausted from an airtight vessel in which an electric appliance which may produce a spark or fire is accommodated, and a controller for enabling operation of the electric appliance when a flow amount detected by the gas flow rate detector when protective gas is fed into the airtight vessel reaches a predetermined level and the internal pressure of the airtight vessel exceeds another predetermined level.

Abstract: The present invention is related to the fluid flow sensing and switching device installed in an air-conditioning system, particularly in a heat exchanger, which has a hollow body or housing to accommodate a metallic sensing member with a pair of conductive terminals extending out thereof, while it is further sealed by resin. A ring member is slidably mounted with a pair of legs extending downwardly from the hollow body, which is positioned facing the fluid flow, so as to activate the metallic sensing means and further to control a compressor connected with the system.

Abstract: A pressure-activated diaphragm valve which when installed in the main up-stream side of a pressurized line, responds to signals from a control unit to shut off the main supply line and at the same time, opens a drain port on the down-stream side of the valve. When used as a freeze protection system, the main water line is shut off and the drain port opened before the freeze point, thereby, eliminating water damage from frozen, broken pipes. The valve also is self-cleaning and has a magnetic plug to remove and keep metallic particles out of the control chamber and the control unit has automatic and manual modes.

Abstract: A protective device for portable apparatus supplied from a high-voltage line is disclosed, which includes a connecting line from an electrical supply. The device also includes a protective switch with contact sets located in the supply lines and pre-stressed contact springs which are maintained in a closed position by a hoop-like fusible wire. An electronic firing circuit is disposed on a flat plate, together with the protective switch and the connections to the supply line and to the apparatus. The two-pole outlet of the firing circuit terminates in contact lugs with which the ends of the fusible wire can be connected mechanically and electrically. The circuit plate is, preferably, seated in the housing of a right angle plug, the contact pins of which are cast or pressed into the bottom of the housing and support the circuit plate while, at the same time, their heads constitute the opposite contact for the contact springs of the protective switch.

Abstract: A safety device for minimizing electrical shock to a user is taught. Briefly stated, a ground plane is disposed inside an electrical tool or device. Should the device become immersed in water or become unreasonably wet, the plane provides a path of electrical current, which energizes an interrupt device contained therein. The interrupt device disconnects power from the device. Further, reset can only be accomplish by a special purpose tool being urged through an aperture in the device case.

Abstract: Disclosed is a method and apparatus for preventing or minimizing scale deposition from hard water onto heat transfer surfaces in atmospheric cooling towers, such as those used in air conditioning and refrigeration systems, where evaporative cooling of water provides the necessary heat sink to the atmosphere. An electrical/mechanical control system responsive to changes in density of the water in the evaporative cooling system operates to permit discharge of water containing dissolved and suspended solids from the system when its density reaches a predetermined maximum value and to discontinue the discharge of cooling system water when its density reaches a predetermined minimum value. Water drained from the cooling system is replaced by fresh water, preferably by water containing chemical additives to increase solubility of hard water minerals in the cooling water.

Abstract: System and method of error reduction in which a comparator is sequentially operated to produce series of pulses in which the time distribution of the pulses is related to the displacement being monitored by the transducer. In particular, the comparator is sequentially operated to provide two sets of pulses using a positive ramp voltage, and then using a negative ramp voltage having a magnitude equal to the positive ramp voltage. Averaged time periods between the pulses are used to eliminate offset errors in the determination of the value that the transducer is monitoring. The transducer is adapted to monitor the substantially linear movement of the level (fuel-air interface) of fuel in a tank and the angular position of an input shaft.

Abstract: There is provided a system for blocking the inflow of water to an appliance such as a hot water tank in the event of a leak in the appliance or water supply thereto. A low voltage current solenoid selectively blocks said inflow in response to a leak. No current is drawn during normal operation of the appliance.

Abstract: A fluid level controller flexibly set up according to the number of level steps to be controlled and the pitch between such level steps, which comprises a plurality of joint pipes connected in series to form a pipe assembly; a ring-shaped magnetic floating member sleeved on such a pipe assembly to follow fluid level to move up and down; a plurality of reed elements having each a reed switch connected in series with one another and received in the joint pipes; a main control circuit comprising latching relays in quantity one less than the quantity of the reed elements and a plurality of controlled actuators respectively connected to the reed elements.

Abstract: The disclosure relates to a water sensor unit wherein a plurality of water related appliances or equipment can be simultaneously monitored and in the event of sensing water with respect to any one of the several items being monitored appropriate action is taken such as shutting off the power to the unit and simultaneously shutting off the water supply to that particular unit. The sensor unit comprises a plurality of electronic circuits which include a "memory" permitting retention of a ground fault even through a power failure for up to 500 hours.

Abstract: The use of a probe for the control of foam build up in a fermenter, which probe comprises a guard electrode (13), first and second insulators (14 and 15) separated by the guard electrode, a detecting electrode (12) separated from the guard electrode by the first insulator, and a plug (18) and socket (17) for connecting the probe to a power source, the second insulator being provided with fermenter mounting means in the form of a flange (16), a sensor comprising the aforementioned probe for use with an antifoam supply regulator, a foam control system and a method of controlling the build up of foam in a fermentation vessel.

Abstract: A fluid level sensor for determining the amount of liquid in a container. Thin metal plates are placed parallely adjacent each other to form a capacitor cell coated with a non-hygroscopic film. The plates are mounted on the walls of the container containing fluid. As the fluid covers more surface area of the capacitor plates, the dielectric properties of the fluid increase the capacitance of the cell proportionally. The plates are connected to an oscillator whose output frequency varies with the change in container fluid levels. By monitoring these frequency changes, the container fluid levels of the fluid in the container can be controlled.

Abstract: A safety device adapted for use in a hand held tool for minimizing electrical shock to a user includes a ground plane disposed inside the electrical tool, which, should the tool become immersed in water or become unreasonaly wet, provides a path for electrical current, which energizes a solenoid which, in turn, interrupts the AC power supply. The safety device is preferably encased in a variety of module. The safety device contains a power supply, such as a battery and/or electret, that is independent of the AC power supply. Thus, the safety device can be tripped even if the tool is not turned on.

Abstract: An automatic cup-filling control arrangement for beverage dispensers utilizes the spray or mist of liquid droplets, formed by flowing beverage striking beverage already in the cup, to complete an electrical circuit. This electrical circuit extends from an electrically conducting member, such as an actuating lever, to beverage flowing through a dispensing valve. When the mist of droplets permits a pre-established magnitude of current to flow between the actuating lever and the flowing beverage, which occurs when beverage in the cup reaches a pre-determined level, dispensing of the beverage is terminated.