Showing papers on "Temperature control published in 1972"

Temperature regulation for electrical heater

Abstract: A temperature control system for use in an electrical heating device wherein the heating element also functions as the temperature sensing element. The resistance of the heating element varies linearly with temperature and the changes in resistance, detected as voltage variations across a wheatstone bridge, regulate the heating. The system is operable in either the A.C. or D.C. mode and includes a temperature measuring circuit, a timing circuit and a control circuit.

Non-contacting temperature measurement of inductively heated utensil and other objects

Abstract: A solid state cool-top induction cooking appliance equipped to set and maintain a selected utensil temperature. A non-contacting temperature sensing technique is based on sensing an inverter power circuit parameter that varies with the utensil temperature, and thus does not require holes in the cooking surface or sensors that project above. The power circuit parameter is typically an interval of oscillation or a damping factor, such as the interval between zero-crossing points of the instantaneous induction heating coil current. The temperature signal derived therefrom is corrected for other circuit factors, for example, a variable input voltage, that also cause a change in the selected power circuit parameter. A user control setting signal can also be summed with the temperature signal. The corrected temperature signal is employed in closed feedback loop fashion to adjust the power coupled to the utensil to maintain the set temperature. The method of measuring and controlling temperature is applicable to inductively heated objects other than cooking utensils, and induction heating apparatus incorporating the temperature control circuitry is useful in a variety of applications.

Temperature regulator for a catalytic reactor

Abstract: Device for regulating the temperature of a catalytic reactor for the depollution of the exhaust gases in internal combustion engines. Cooling of the exchange surfaces of the reactor by a flow of air the flow-rate of which is substantially proportional to the increase in temperature of the reactor, the said flow being interrupted when the temperature drops below a predetermined level. Means responsive to the reactor temperature control the regulation of the cooling air flow. The catalytic depollution of exhaust gases of internal combustion engines.

Radiant energy heating system for temperature control of living subjects

Abstract: A temperature sensor attached to a living subject and is connected to a control circuit having an input for connection to a source of alternating current power and an output from which half-waves of the alternating current power are generated when the temperature of the sensor falls below a first temperature and full-waves of the alternating current power are generated when the sensor falls below a second temperature The output of the control circuit is connected to a plurality of pre-focussed incadescent lamps with infrared filters, the lamps directing infrared radiant energy to a region of controlled temperature within which the temperature sensor and living subject are located

Metal base cookware induction heating apparatus having improved control circuit using infra-red temperature sensor

Abstract: A metal based cookware induction heating apparatus having an improved power supply and control circuit comprised of a chopper inverter including a gate controlled power thyristor coupled to and supplying an induction heating coil with periodic energization currents The gating circuit controlling operation of the chopper inverter is controlled by a temperature sensing arrangement that includes an infra-red heat sensor device arranged to view the metal-based cookware or other object whose temperature is to be controlled A constant current amplifier is connected in series circuit relationship with the infra-red heat sensor device across a source of low voltage direct current excitation potential and means are provided for periodically interrupting the view of the infra-red heat sensor device to produce an output alternating current signal component whose amplitude is indicative of the temperature of the metal-based cookware or other object being heated An alternating current amplifier including an adjustable temperature set resistor is coupled to the output from the infrared heat sensor device with the setting of the adjustable temperature set resistor serving to control the gain and establish the temperature level at which the output from the alternating current amplifier attains an operative level of magnitude An output on-off control amplifier either in the form of a Schmitt trigger type of circuit or reed relay is coupled to and controlled by the output from the alternating current amplifier for producing an amplified output on-off control signal representative of the temperature of the metal-based cookware or other object whose temperture is being controlled in accordance with the temperature setting of the adjustable temperature set resistor The on-off output from the temperature sensing arrangement control an inhibit circuit connected to and controlling a zero point sensing and control circuit that in turn controls the operation of a soft starting zero point switching device connected intermediate the rectified ac supply terminals and the thyristor switching device employed in the chopper inverter whereby both radio frequency interference effects and audible noise production by the inductive heating coil during energization periods from the chopper inverter is substantially reduced due to the fact that energization of the coil under the control of the temperature sensing arrangement is inhibited until only the beginning or near the beginning of each half cycle of the rectified full wave potential appearing at the output from the high voltage rectifier To further reduce RFI effects, a smoothing inductor having an inductance L3 and a smoothing capacitor having a capacitance C3 is connected in series circuit relationship across at least one of the commutating components of the chopper inverter power supply circuit The combined impedance of the commutating capacitor, the smoothing inductor L3 and the smoOthing capacitor C3 is capactive in nature and is series resonant with the communtating inductor L1 to establish the commutating period t1 The smoothing inductor and the capacitor serve to shape the output current flowing through the smoothing inductor which is used as the inductive heating coil to substantially a sinusoidal waveshape having little or no radio frequency interference emission effects Additionally, a capacitor switching arrangement is provided for the commutating capacitor C1 which is formed from a plurality of parallel connected capacitors and power rate controlling switching means for switching selected ones of the parallel connected capacitors into effective circuit relationship in the chopper inverter circuit in accordance with a desired rate of power production Where the improved induction heating apparatus is employed in connection with metal-based cookware, the inductive heating coil preferably is in the form of a helically-shaped planar inductive heating coil and is disposed under a heat transparent member such as an infra red transmissive pyroceramic that can form a smooth continuous tabletop over the induction heating unit and itself does not become heated except by conduction and convection from the metal-based cookware The inductive heating coil excites and heats the metal-based cookware directly so that all heat is generated only by the metal-based cookware and no excess waste heat is produced in the manner of known resistance heating units Since the temperature sensing units directly views the bottom of the metal-based cookware through the heat transparent member and controls the application of power to the induction heating coil, temperature control is directly related to the actual temperature of the pan or other object being heated by the induction heating apparatus As a consequence, a considerable improvement in efficiency and reduction of waste heat results Temperature control is accurate, rapid in response and there is no overshout in temperature such as is characteristic of temperature control systems which control the temperature of a heat source which is external to the object being heated Improved arrangements for the heat transparent member, infra-red heat detector, chopper device, and cooling fan together with preferred designs for the inductive heating coil with ferrite core of without to maximize coupling to the metal-base cookware or other object being heated, are described whereby further improvements in efficiency of operation, economy of components and minimum size are achieved

Review of Thermal Control Materials for Metallic Junctions

Abstract: THE use of thermal control materials, or interstitial materials, appears to be one of the most promising methods for the control of heat transfer in the metallic joints of spacecraft structures and electronic equipment. The thermal conductance of a metallic joint, including a thermal control material, provides a measure for rating the effectiveness of the material for thermal control. In order to make a direct comparison between the contact conductance of thermal control materials determined in previous experimental investigations of joint conductance, a dimensionless parameter incorporating the thermal conductance has been formulated. This dimensionless parameter is applied to the results of previous investigations to illustrate the relative effectiveness of a range of thermal control materials.

Temperature-control system with rotary heat exchangers

Abstract: An independently heated or cooled room is linked with an environment of different temperature through a fluid-circulation system including a closed path traversed by a heat-carrier medium. The medium travels between two heat exchangers, respectively located in the warmer and in the colder air, under a pressure differential low enough to maintain a coherent flow at substantially uniform speed in one or more pairs of channels extending between the two heat exchangers.

Coolant control for hot strip mill

Abstract: The disclosure of the present invention relates to a strip temperature control method and apparatus for a finishing train of a hot strip rolling mill, including strip interstand coolant supply means, and a control for varying the rate of flow thereof, which includes a feed-forward control signal wherein the rate of flow is controlled in certain stands with reference to a computed temperature and a desired temperature of the strip as it leaves the train, and a feed-backward control signal wherein the rate of flow is controlled in one or more stands with reference to the actual temperature and a desired temperature as it leaves the train

Apparatus for temperature control for a heated rotating cylinder

Abstract: Apparatus for controlling the surface temperature of a heated roll which, in conjunction with a backup roll, is utilized to feed sheets for fixing tones images, for example, a heat sensing device such as a thermistor is positioned within the thermal boundary layer surrounding the heated roll to sense the temperature change of the air within the boundary layer adjacent the heated roll and to generate an electrical signal representative of the temperature changes. The signal is utilized in conjunction with a temperature controller to control the temperature of the heated roll so that the heat energy transferred to the paper sheet is accurately controlled.

Temperature control system for centrifugal liquid chilling machines

Abstract: An improved temperature control system for centrifugal compressors in refrigeration equipment for elimination of ''''droop'''' associated with proportional position control is disclosed using a two thermistor temperature sensing unit for sensing both the temperature and the rate and direction of change of the temperature of the chilled liquid from the evaporator and for producing a change in the pre-rotation vane setting. The rate and direction of change of temperature is obtained by comparing a fast and a slow temperature signal in a summing amplifier to control a pulse width modulator that modulates a sawtooth generator to control a vane motor through appropriate logic. The fast temperature signal is also compared with a unit cycling thermostat reference signal in a Schmitt Trigger to de-energize the compressor when that temperature signal reaches the reference level. The fast temperature signal is also used to drive a recorder.

Temperature control system with multiple thermostats

Abstract: A heating-cooling control system includes thermostats in the discharge and return air passages, and a temperature set dial. A selection circuit energizes one of the thermostats below a preset temperature, and the other thermostat is energized above that temperature. A heat override circuit prevents a call for heat above a certain temperature. With two compressors, the first compressor is maintained off by a timer circuit for a short time to prevent cycling of the compressor. Another timing circuit briefly delays operation of the second compressor, when the cooling system calls for its operation, to prevent simultaneous energization of both compressors and an excessive demand on the electrical supply line or unit.

Recovery of natural gas liquids by partial condensation

Abstract: In the recovery of natural gas liquids by partial condensation, flashing, and compression, minimum and maximum temperature control of partially condensed feed stream hydrocarbons to a product separator is imposed by a minimum temperature control system which provides the same set point to the pressure controllers on the compressor suction scrubbers for both the product and the flashed vapor produced from the liquid outlet of the product separator with one of the two output signals responsive to the pressure of the product suction scrubber or the flashed vapor suction scrubber manipulating, by way of a selective relay, the engine speed controller of the dual compressor unit taking suction from the two scrubbers; and a maximum temperature controller which controls the rate of by-pass of natural gas feed around the partial condensation-separation system unless, by means of a selective relay, compressor availability is a more limiting criterion

Temperature control apparatus for a centrifugal-type chemistry analyzer

Abstract: A temperature control apparatus for raising and controlling the temperature of small volumes of liquid by heating the liquid and detecting the instantaneous temperature and rate of temperature increase and utilizing this information to control the heating of the liquid so that the desired liquid temperature is attained and maintained in a minimum time interval.

Automotive vehicle automatic temperature control system

Abstract: Automatic temperature control system for the passenger compartment of an automotive vehicle. The control is by vacuum modulated by the temperature of ambient air and the temperature of air in the passenger compartment of the vehicle and includes a vacuum motor operated by modulated vacuum regulating the position of a plenum mounted air blend door, controlling the passage of cold, tempered or heated air into the passenger compartment and positioning an electrical programmer, to provide the desired blower speeds and certain program functions of the system.

Temperature control of stator/rotor fit in helical gear pumps

Abstract: Loss of capacity in a helical gear pump resulting from wear of parts is restored by raising the temperature of the stator, or by raising the temperature of the stator and also the temperature of the fluid being pumped. Regardless of the state of wear, the capacity of a helical gear pump operating against elevated discharge pressures is improved by raising the temperature or temperatures as above, whereby to produce a tighter fit between the elements. Various alternative means for raising the temperature or temperatures are disclosed.

Heating rate controller for thermally stimulated conductivity and thermoluminescence measurements.

Abstract: A temperature controller is described which enables the temperature of a sample mounted on a cold finger to be varied linearly with time. Heating rates between 0.5 and 10 K/min can be achieved for temperatures between 90 and 300 K. Provision for terminating the sample heating at any temperature between these extremes is available. The temperature can be held at the terminating temperature or be reduced to the starting temperature in a matter of minutes. The controller has been used for thermally stimulated conductivity measurements and should be useful for thermoluminescence measurements as well.

Air conditioning systems

Abstract: An air conditioning system, especially for aircraft cabins, has a temperature control loop incorporating a signal processing control stage, in the form of a pulse logic network, to derive, from the difference or error signal received from a comparator, a control output signal suitable for driving a regulating motor to change the air flow conditions in a fresh air duct supplying the cabin. The cabin temperature is advantageously sensed by a resonant tube acoustic device delivering a pneumatic pressure oscillating output which is compared with a reference pulse frequency in fluidic logic of the comparator to derive a pulse frequency representing the difference or error. The control stage in turn derives from the error pulse frequency the regulator driving output, which is advantageously a polyphase output driving a stepping motor.

Development of a thermal diode heat pipe for the advanced thermal control flight experiment /ATFE/.

Abstract: Description of the analysis, design, fabrication, and test of the engineering model of the ATFE diode Included is a review of several diode concepts that led to selection of the liquid blockage technique for shut-off The diode is made of stainless steel, 26 in long, 0375-in nominal OD, with self-filling spiral artery wick and ammonia working fluid In the normal heat pipe mode, at ambient temperatures, the diode capacity is 85 W For flight, the pipe will deliver 20 W with a 9 F temperature difference between the external evaporator and condenser surfaces Reverse mode conduction is less than 15 W with a 260 F temperature difference

A liquid cooled garment temperature controller based on sweat rate

Abstract: An automatic controller for liquid cooled space suits is reported that utilizes human sweat rate as the primary input signal. The controller is so designed that the coolant inlet temperature is inversely proportional to the subject's latent heat loss as evidenced by evaporative water loss.

Filament-current control unit in electron-beam apparatus

Abstract: An electron-beam apparatus is provided with an electrode for intercepting a portion of the electron beam so as to achieve automatio cathode temperature control. The filament current is controlled by means of a signal derived from this interception electrode.

Device for continuous temperature measurement of dew point of flue gases

Abstract: A device for continuous temperature measurement of the dew point of flue gases, in which the signal of the sensitive unit, carrying information on the appearance of a condensate film on the condensation surface of the dew point temperature transmitter, is applied simultaneously to the regulator of the heating element and the regulator of the cooling element. Both of these are included in the condensation surface temperature control unit, wherein temperature control of the condensation surface is attained by the heating and cooling means operating simultaneously. The transmitter is provided with heating and cooling means.

Temperature control systems

Abstract: Temperature control systems or regulating circuits for use with electrical heating elements of burners of electric ranges, hot plates or cook-tops, such circuits and elements being directly energized from conventional or commercial sources of power, such as 60 c.p.s. alternating current sources of 120 or 240 volts, and which systems provide high-temperature sensing and adequate temperature-limiting. An encapsulated high-temperature wire sensor is used in conjunction with thermal or electromagnetically actuated devices or relays, and solid state circuitry comprising a balanced amplifier-detector and at least one silicon controlled rectifier as a switch or switching device. The necessity for a step-down transformer is eliminated by the systems disclosed and an economic advantage is thereby attained. The control systems are especially suitable for use with electrically heated glassceramic cook-tops in order to provide higher temperatures and improved cooking performance when cooking vessels with non-flat bottoms are used with such cook-tops, while at the same time providing temperature-limiting of the burner system of the cooktops for both electric heating-element protection and cook-top protection.

Vapor generator and control therefor

Abstract: The vapor generator provides a uniform and controllable heat input for vaporizing organic working fluid in a vapor engine. A fluid-tight enclosure is partially filled with a heat transfer fluid for transferring heat from a heat source to organic working fluid conducted through the enclosure in a convoluted tube. A simplified pressure responsive temperature control apparatus provides safe and accurate operation.

A fully automated (Faraday) magnetic balance

Abstract: An Alpha (Systron-Donner) 4in. (pole-piece) variable temperature magnetic balance has been converted to fully automatic operation. The output from an Ainsworth electrobalance is fed into an inexpensive multiplexing unit which also receives a signal, proportional to the temperature of the sample, from the temperature control unit. The magnetic field is switched on and the sample cooled to liquid nitrogen temperature.

Physiological and engineering study of advanced thermoregulatory systems for extravehicular space suits

Abstract: Investigations of thermal control for extravehicular space suits are reported. The characteristics of independent cooling of temperature and removal of excess heat from separate regions of the body, and the applications of heat pipes in protective suits are discussed along with modeling of the human thermal system.

Temperature control conductive device

Abstract: A passive temperature conductive device for use in mounting flight control units in a missile. The device controls conduction of heat to provide maximum conduction during pre-launch operation from the units and minimum conduction to the units at high altitude flights. The mating surfaces of a conductive joint allows heat to flow freely from the units to the missile skin during pre-launch operation, but restricts the reverse flow of aerodynamic heating into the units during flight.

Atmosphere revitalization in the space station prototype.

Abstract: The atmosphere revitalization group (ARG) for the space station prototype (SSP) environmental/thermal control and life support system (ETC/LSS) has been designed to meet a comprehensive set of requirements and constraints for a flight type mission. Design definition is for a modular vehicle temperature and humidity control subsystem, contaminant control equipment, a hydrogen depolarized cell CO2 concentrator, a water electrolysis oxygen generation subsystem, CO2 reduction equipment, and a pressure and composition control subsystem. Performance requirements are for support of a crew of six. Realistic leakage rates and metabolic activity cycles, cabin temperature selectability, and controlled cabin relative humidities are specified for the design. Operational aspects of the subsystem are discussed with emphasis given to the influence of a 180-day, maintainable requirement on system design. Consideration of flight vehicle type packaging, in flight maintenance, data management systems interface and fault detection capability, and electrical supply constraints is covered.