Abstract: A thermostatic control for electric cables used on overhanging eaves of pitched roofs in northern climates, and in rain gutters and downspouts, comprises a high temperature-limit switch and a low temperature-limit switch connected in series circuit for controlling energization to a narrow temperature range extending from the freezing temperature of water to several degrees colder. Above-freezing temperatures will melt ice and snow without supplemental heating, and sufficiently colder temperatures will not be raised sufficiently by heat loss through a building roof to thaw ice and snow accumulation on the roof and provide run-off water to the unheated eave, rain gutter and downspout where freezing can occur and result in the formation of an ice dam which will block drainage of further run-off water and which may grow in size to cause water to back-up and seep under roofing shingles to leak through the roof.

Abstract: An electron beam processor with an energy storage line and matched field emission diode that define a high energy electron beam generator. A transport system positions a specimen to be thermally processed in a processing station. Energy stored on the line is discharged through the diode and the resulting high energy beam impacts upon the specimen for thermally processing selected regions thereof.

Abstract: An EDM method and apparatus for machining a workpiece electrode with a tool electrode wherein a solid-state switching type EDM generator provides a succession of machining current pulses across a machining gap formed between the electrodes flooded with a liquid dielectric, preferably distilled water or a weakly conductive aqueous liquid, through a gap discharge circuit. The total value of stray capacitances in the gap discharge circuit is limited to be less than 0.01 microfarad, preferably at most 0.005 or 0.001 microfarad, to control a rise of peak current at the leading edge of each individual machining current pulse. The gap current at the leading edge of a pulse may be sensed and discriminated to provide a control signal which acts on the DC power supply to control the output voltage thereof so that the initial rise of peak current may be maintained substantially constant, irrespective of a change in the stray resistance in the gap discharge circuit during a given course of machining operation.

Abstract: A power control arrangement for controlling the power output of a resistive heating element of the type having a fast thermal response time and a highly variable resistance with temperature. The power control arrangement includes a plurality of operator selectable power settings and an electronic switching system responsive to operator selection of these settings to rapidly couple and decouple a power supply to the element. The switching action is selected to permit rapid heat up of the element without causing an unacceptable current to flow and to prevent excessive cooling of the element after it reaches operating temperatures during steady state operation.

Abstract: Sensor and reference wires are directly exposed to the airflow past a vehicle. The wires are electrically conductive, and each has a resistance varying with its temperature. A continuous fixed voltage is passed through the reference wire. A short pulse of greater constant voltage is passed through the sensor wire, the voltage of sufficient magnitude to cause the rapid heating of the sensor wire during the pulse. The resultant rate of heat of the sensor wire, and its final temperature at the end of the pulse, is determined by whether ice or water is on the sensor wire. Circuitry is provided to generate an ice present signal when the difference in current flow during the pulse through the sensor wire and through the reference wire is of such magnitude and sign as to indicate that ice was in contact with the sensor wire. Due to water's heat of fusion, the effect of ice on the sensor wire is readily distinguished from the effect of water.

Abstract: A step controller for a water heater having a plurality of individual electrical heating elements changes the number of energized elements to maintain a predetermined minimum temperature. A thermistor sensor monitors the temperature of the water and generates a proportional signal. Preset potentiometers establish set point temperature signal and a dead band signal. The number of "on" elements is related to the difference between the sensed water temperature and the preset water temperature divided by the dead band factor. The heating elements are turned "on" and "off" in a predetermined sequence whenever a change is required. The sequence includes turning on the heating element which has been off for the longest period and turning off the heating element which has been on for the longest period.

Abstract: A control system and method for an apparatus to glow discharge treat (such as ion nitride) a workpiece. The apparatus includes a housing to receive a workpiece and a low pressure atmosphere of ionizable gas (nitrogen and hydrogen for nitriding), and connectors for establishing a glow discharge in the gas with the workpiece connected as the cathode. The control system and method automatically control the apparatus throughout the process, utilizing operator selected parameters (such as warm-up time, processing time, workpiece operating temperature and chamber pressure). The control system divides the selected operating temperature by the selected warm-up time to provide a straight line increase per unit time of the workpiece temperature. Initially the control system accumulates the increases at a rate higher than the straight line increase and then, as the workpiece approaches the selected operating temperature, the control system accumulates the increases at a rate less than the straight line increase.

Abstract: An arrangement for detecting abnormal concentration of electrical discharges between a travelling wire electrode and a workpiece in a travelling wire EDM apparatus. The abnormal electrical discharge detector of the invention comprises a circuit measuring the voltage across a pair of contacts supplying machining current to the electrode wire. The length of the electrode wire between the two contacts forms a pair of variable resistors connected in a branch of a Wheatstone bridge circuit. The voltage measuring circuit, connected across a diagonal of the bridge, in turn controls some of the machining parameters such as to prevent damages, as for example rupture of the wire electrode, when an abnormal concentration of electrical discharges is detected at a given point of the machining zone between the wire electrode and the workpiece.

Abstract: A method of cutting a workpiece in a desired configuration by using an electric discharge andrelatively moving the workpiece and a wire electrode. When cutting a waste work part of the configuration, the wire electrode is stopped and shifted backwardly for a predetermined distance. The wire electrode is then shifted perpendicular to the work direction until it contacts the wall of the workpiece so as to measure the discharge gap.

Abstract: A control system for a heating unit that has controls for comparing a variable electrical signal that has a value in relation to the output temperature of the heating unit and a selected electrical signal that has a value in relation to a selected temperature setting to control the operation of the heating unit to tend to produce an output temperature substantially equal to the selected temperature, the controls including a control device having a rod and tube temperature sensing unit for providing linear motion of a part thereof in relation to the output temperature of the heating unit and having a potentiometer provided with an electrical output producing part operatively interconnected to the movable part of the rod and tube unit so as to produce the variable electrical signal in relation to the output temperature of the heating unit.

Abstract: Apparatus for disconnecting electrical powered devices from a source of electrical energy when the use of the devices is no longer needed. The apparatus includes an electrical switch movable in response to an actuation member. The switch is connected between a source of electrical energy and an electrical powered device so as to selectively connect/disconnect the device to the source of electrical energy depending upon the use of the actuation member. A second electrical switch, also responsive to the actuation member, is connected between the source of electrical energy and another electrical powered device, such as a heating/air conditioning unit, to connect/disconnect the heating/air conditioning unit to the source of electrical energy. One temperature responsive device is associated with the second electrical switch in order to maintain the room temperature above a predetermined minimum temperature.

Abstract: In a system in which temperature control of a heated region is critical, assurance means of fail-safe nature are provided to guard against improper temperature. An example wherein temperature is critical is: the artificial ventilation of an unconcious patient's lungs by periodically inspired heated gas under pressure. The assurance means includes dual thermometers which sense the actual temperature in the heated region. The actual temperature is compared with the desired temperature to control an electric heater, which, when energized, increase the temperature of the heated region. Furthermore, the temperatures, as sensed by the two thermometers, are compared with each other. If the difference exceeds a predetermined limit, an alarm is given and the heating system is shut down.

Abstract: A continuous beam from a laser is divided into two intermittent beams by a reflecting disc with peripheral holes, rotating about an axis skew to the continuous beam. At least one of the intermittent beams is transmitted to a marking head having a lens which focuses the beam onto the surface of a roll. The roll is rotated and the marking head is moved along the roll, in synchronism with the rotation of the disc, so that a regular hexagonal lattice of microcavities is cut by the focused intermittent beam. The second intermittent beam may be used to cut microcavities in the roll or in a second roll or for other purposes.

Abstract: The invention relates to an electric temperature setback device which is placed in proximate relation to a conventional thermostat and is operatively controlled by a timing device for providing local warmth to the thermostat at pre-determined times and for pre-determined intervals. The setback device includes spades with integral female lamp connectors for arraying a plurality of incandescent lamps in series across an electrical circuit. By so doing, the voltage to each lamp is proportionally reduced, decreasing the filament temperature of each lamp and thereby increasing the amount of heat energy produced proportional to the amount of light energy produced.

Abstract: A primary thermostat is provided in a fryer of the type comprising a frypot containing cooking oil, a heater, heat control switching means for operating the heater and a thermostat including a temperature probe, the fryer thermostat being used as a backup to the primary thermostat. The primary thermostat utilizes the signal of a temperature probe associated with a cooking computer which calculates the cooking time period for food items cooked in the fryer. The primary thermostat includes comparators monitoring for open or shorted conditions of the cooking computer temperature probe, and a control transfer relay which switches thermostatic control of the fryer from the primary to the backup fryer thermostat in the event of probe failure. The primary thermostat also includes a temperature selection switch for selecting a desired temperature of the cooking oil and temperature control circuitry for operating the fryer heater to maintain the desired temperature.

Abstract: A temperature responsive switching device is provided in which a pair of spaced bimetallic electrical switching arms each are anchored to opposite sides of a mounting block for attachment to the respective power leads of an electrical supply circuit. The free end of the spaced bimetallic arms each contain an electrical contact. A central arm is disposed between the contacts and has a neutral contact mounted thereon such that each of the contacts on the bimetallic arm is biased at room temperature into contact with the central electrical contact. Upon one of the bimetallic arms experiencing a predetermined temperature the circuit is broken by deflection of the bimetallic arm. Upon the switch experiencing a second predetermined but higher temperature, the second bimetallic arm is deflected to open the circuit.

Abstract: A remote control device for controlling the operation of a conventional domestic water heater (18) used singularly or in conjunction with a solar heating system. The control device comprises a remote control head (10), which has an indicator (12) for conveying the status of the water heater (18) and the temperature of the water contained therein and a multi-positional manual switch (14) for selecting the mode of operation of the water heater (18) and a remote controlled heater switch (16), electrically connected to the remote control head (10), which controls power to the water heater (18) in response to signals from the remote control head (10). Therefore, the operation of the water heater can be controlled according to the needs of the user.

Abstract: Disclosed is a method of plasma treatment of materials comprising introducing a plasma-forming mixture including carbon-containing compounds chosen from the class of hydrocarbons or carbon monoxide into the space between the electrodes of an electric arc device to provide deposition of carbon at least on one of the electrodes of an electric arc device in the course of arc burning, striking an electric arc, and introducing an oxidizing agent into said space between the electrodes to improve the stability of arc burning, the oxidizing agent being introduced into said space between the electrodes over a time interval between the instant when a heat flow into the electrode whereon carbon is deposited reaches its maximum value and the instant when said heat flow drops down to a steady value.

Abstract: A temperature-controlling circuit including a heating element, a portion of which is shunted by a proportional PTC thermistor having a low rate of charge of resistance with increasing temperature that controls current to the shunted and unshunted portion of the heating element to provide a proportional control of temperature. Additional embodiments are disclosed in which additional circuit elements are employed to further control current through the heating element, and in which a second thermistor connected in series with the shunted portion of the heating element accommodates wide voltage swings.

Abstract: An energy saving food serving system for rethermalization of the food and for delivery prepared meals to locations remote from the place of preparation, such as to patients to hospitals and nursing homes. The system includes a mobile cart having its own rechargeable power pack that is utilized to propel the cart. The cart has separate bays, each having a tier of racks for carrying individual food serving trays. Each tray has one or more thermally isolated heat transfer devices which are selectably energized when the tray is in place on a rack in the cart. Preferably, each tray has a pair of heaters referred to herein as plate and bowl heaters and adapted to be operated by control means in either a continuous mode of operation or a rethermalization mode of operation.