Showing papers on "Temperature control published in 1970"

Two-shaft gas turbine control system

Abstract: In a two-shaft gas turbine having an adjustable nozzle between the compressor high-pressure turbine and the load turbine, a control system is provided in which a biasing signal is added to the fuel temperature control increasing its base reference so that on an increase in called for speed or load the gas turbine is able to dynamically respond in an improved manner. The steadystate temperature limits are exceeded transiently without damage to the gas turbine until the system returns to its new steadystate condition. Also provided for the two-shaft gas turbine is an acceleration limiting control whereby the overall gas turbine is allowed to accelerate at the maximum allowable value of either of the two shafts. Further provision is made for a blowoff valve control whereby excess energy from a regenerator is diverted from the turbines so that the speed and load control will remain in command, thus preventing overspeed conditions and/or subsequent shutdown.

Air temperature control system

Abstract: A multizone room air temperature control system comprises a thermostatically controlled louvered vent unit fitted to the mouth of the preexisting air duct register of the heating and air-conditioning system, in each room whose temperature is to be controlled. A continuously energized reversible shaded pole motor connected to the thermostat automatically opens and closes the vent louvres in response to room air temperature changes to thereby introduce or shut off the supply of either warm or cold air into the room for regulating the room air temperature independently of the other rooms.

Temperature control system for space suit

Abstract: A temperature control system for a space suit having a warm fluid loop and a cold fluid loop with a mixing valve for adding fluid in the cold loop with fluid in the warm loop. A sensor is provided to control a throttle in the cold fluid loop for regulating the amount of fluid being added from the cold loop to the warm loop.

Automatic temperature control system for extruders for molten material

Abstract: Automatic temperature control system for extruders having a plurality of heating zones which includes an electronic controller for controlling the electric heating power supplied to each zone, a temperature sensing device adapted to supply a signal to the controller representing the temperature of molten metal at the extruder head. The controller is in communication with all the heating zones and is adapted to control thyristortype active networks associated with the respective heating zones which regulate the electric heating power supplied to each zone in a pre-set adjusted ratio.

Controlled temperature corrosion testing probe

Abstract: A PROBE FOR TESTING THE CORROSION RESISTANCE OF A SPECIMEN OF A MATERIAL TO A STREAM OF CORROSIVE FLUID COMPRISING MEANS TO ELECTRICALLY ISOLATE THE SPECIMENT FROM THE PROBE AND MEANS TO CONTROL THE TEMPERATURE OF THE SPECIMENT. TEMPERATURE CONTROL IS ACCOMPLISHED BY FLOWING HEAT CONDITIONING FLUIDS, SUCH AS STEAM OR COLD WATER, THROUGH THE PROBE, WHILE ISOLATING THE SPECIMENT FORM THE HEAT CONDITIONING FLUID.

Safety load and temperature control system for microwave ovens

Abstract: A safety load and temperature control system for microwave ovens wherein a variable volume of water is passed through the oven for controlling the amount of energy received by a work piece therein. Microwave energy from magnetron tubes is introduced into the oven chamber for processing a work piece. The variable supply of water within the chamber is increased for small parts being cured and decreased for large parts being cured. The water is passed through a dielectrically transparent vessel within the chamber and is heated by the microwave energy proportional to the heated work piece or part. The temperature of the water leaving the chamber is indicative of the rate of change of the work piece temperature. A temperature controller has upper and lower limits that increase or decrease the water in the chamber and passing therethrough to maintain the work piece heating rate within a desired range. The variable supply of water also serves as a dummy load to absorb excessive radiant energy, preventing destructive feedback to the magnetron tubes. Microwave filters at water inlet and outlet ports keep the high frequency energy within the chamber.

Heat-retaining mattress for temperature control in surgery.

Abstract: to eight and there are two other buttons, nine and zero, so that a man can supply numerical data such as his age and check number. There is also a button he can use to cancel a wrong answer and a button which switches on a microphone and tape-records any verbal comments that may be necessary. The sets of pictures and words are recorded on film and projected on to the screen by the optical device of a standard teaching machine, but the system for presenting the questions needs to be much faster and more flexible than that used in normal machines of this type. The circuitry and the question sequence are such that the answer button a man presses also determines which question he is asked next. He may simply be asked the next question on the film, but there is a range of other possibilities, and it can sometimes happen that the operation of each of the eight principal answer buttons introduces a different question. Thus though the machine may be able to ask more than a thousand questions covering different circumstances and types of accident, it will by-pass irrelevant questions and ask only the limited number of questions that apply to the accident concerned. Each answer is recorded in a form that can be automatically transferred to paper tape. When necessary, the operator transferring this information can make any modifications that result from the verbal comments of the injured man. The resulting paper tapes are in a form immediately ready for computer analysis.

Temperature control system with a pulse width modulated bridge

Abstract: A temperature control system is disclosed which includes a modified wheatstone bridge with a resistive-capacitive (RC) circuit in one leg of the bridge. The RC circuit includes a resistor which provides an effective resistance as a function of its absolute resistance and the on-time to off-time ratio of pulses supplied to a switch connected thereacross. A sawtooth voltage is produced across the RC circuit, the voltage being compared with the voltage across a temperature sensor, with heat being applied during each pulse period portion when the sawtooth voltage exceeds the voltage across the temperature sensor.

Temperature control system for a car cooler

Abstract: A control system for a vehicle compartment cooler has been provided wherein the cooler is driven by an internal combustion engine through a magnetic clutch having a detector for providing an indication of the compartment temperature. The improvement includes, a revolution detecting means and electrical circuits associated therewith, responsive to the ignition coil for producing a train of signal pulses indicative of number of revolutions of the engine. Circuit means responsive to temperature detector and the revolution detector outputs, produces a control signal when its respective inputs are such that they respectively indicate that the engine speed and the compartment temperature have exceeded selected limits. A switching circuit is provided in order to engage the magnetic clutch for driving the cooler in response to said output control signal.

Improvements in or relating to the Control of Thermal Conditioning Systems

Abstract: 1,193,711. Automatic temperature control systems. HONEYWELL Ltd. Feb. 16, 1968 [Feb. 24, 1967], No. 9080/67. Heading G3R. A system for heating or cooling providing a temperature in a space at a predetermined time comprises a timer for generating a set point signal which progressively approach a value representative of a determined temperature throughout an interval immediately preceding the determined time which signal is modified by a second signal representative of thermal conditions outside the space and means for comparing the modified set point signal with a signal representative of space temperature and producing an output signal when a comparison indicates two are equal, such output signal initiating operation of the system. The desired temperature at various periods during a day is represented by a dotted curve AJCD and the actual room temperature by a solid line curve ABCD. When the room temperature drops during say the night to point B the system cycles at this low temperature until point C is reached when a gradually increasing set point signal actuates a heating system so that at some determined time say 9 a. m. the determined temperature is reached in the room. The set point signal is derived from a resistor (8) Fig. 3 (not shown) which is positioned by a cam driven by a timing motor (9) the resistor forming one arm of a bridge circuit (2). A further bridge circuit includes an outside temperature sensor which modifies the set point signal so that it may follow, for example a dotted curve HD. When the outside temperature is higher as in these conditions the heat losses are smaller the room temperature may fall along a curve AE and heating will commence after point in time at E. The bridge circuit through an amplifier may operate a relay controlling a boiler and circulating pump but other types of heating systems e.g. ducted air with an electrical, oil fired or a gas fired source are envisaged. The system is also applicable to off peak electric storage heating systems in which the final temperature D may be arranged to be above a normal comfort zone as further energy is not available after the end of such off peak period. Switch on of such heaters is arranged to be earlier when the outside temperature is low. The signals may be represented by pneumatic as liquid pressure signals. During the day, the temperature may be maintained at a set value DA by thermostatic means (not shown) and the set point driven to a higher value HL than this by suitably shaping the cam.

Interaction index for multivariable control systems

Abstract: An interaction index is defined for a linear time-invariant multivariable control system which gives a measure of the degree of interaction which will occur when two or more linear time-invariant proportional-feedback control systems are applied simultaneously to the system. The index is simple to compute, and so should be useful in predicting when interaction will occur in large multivariable control systems. A numerical example of a distillation column with pressure control and temperature control is included.

Thermocouple temperature control system

Abstract: The present system provides a circuit wherein a direct-current amplified difference signals is produced in response to an extremely small difference signal being developed by comparing the small voltage developed across a thermocouple, (acting as a temperature sensor) aNd a selectable variable voltage representing the desired temperature of the location being monitored. The amplified direct-current difference voltage is attenuated and fed back to an operational amplifier to develop a stable difference signal input thereto. In addition, the amplified direct-current difference voltage is applied to the control element of a switching circuit. The switching circuit has a pulsating direct-current signal applied to the input-output elements and switches to turn on the heating means in response to the value of the applied difference signal (which is applied to the control element) exceeding a predetermined percentage of the value of the applied pulsating direct-current signal.

A crystallizer for growing single crystals from a solution with very precise temperature control

Abstract: The paper describes a crystallizer for growing single crystals from a solution by the method of temperature decrease; it is intended for studying the influence of growing conditions on the perfection of the crystals and for the actual growing of single crystals with minimum number of defects. The apparatus works in a temperature range of 30 to 80 °C, keeps the set temperature constant with an accuracy of ±0.002°C and automatically performs the temperature decrease at a constant rate of 0.002 °C/day to 5 °C/day. It provides for a wide variability in the volume of crystallization solution, in the stirring regime and in the method of fixing the seed. The design of the mechanical and electronic parts of the apparatus permits reliable operation even when the growing period lasts for several months. A special arrangement prevents a temperature shock when the crystal is removed from the crystallizer. Experience gained over a year of operation is also described.

Thermal network correction techniques

Abstract: Correction techniques for thermal network lumped parameter inaccuracies with conduction and radiation coupling, considering temperature control system

Automatic temperature control apparatus for poultry houses and the like

Abstract: Temperature control apparatus for a building having a ventilation opening therein over which a closure is movable in opposite directions to vary the opening size and wherein a series of temperature ranges of a multi-stage thermostat correspond respectively to stationary positions of the closure. When the temperature in the building rises or falls beyond any of the ranges, the direction of closure movement is electromagnetically selected, followed by movement of the closure toward and adjacent stationary position corresponding to the next temperature range. The invention is characterized by the provision of a limit switch individual to each directional movement in each temperature range, and a trolley-type switching hog roller movable with the closure and adapted to travel back and forth across these switches. During this travel, the switch corresponding to the next stationary position the curtain is to occupy will be actuated to arrest the closure in the latter position.

Cooler control system for automobile coolers

Abstract: A cooler control system suitable for automobile coolers. It includes an engine speed detection circuit and a temperature control circuit to control the operation of a cooler through the combination of these circuits, thereby separating the cooler from the engine to reduce the engine load during low engine speed operation so as to overcome the insufficiency of the engine output under the low engine speed operating condition. The engine speed detection circuit of the cooler control system according to the invention includes an integrating capacitor, whose discharging circuit comprises a transistor, diode and resistor, whereby the fluctuation of the preset engine speed is prevented.

Pneumatic control system

Abstract: This disclosure relates to a vacuum temperature control system wherein a pair of vacuum signals respectively from a temperature sensor and a temperature selecting means are translated by a comparator into a vacuum control signal that operates a temperature output means for the system in relation to the vacuum control signal to produce a proportional action thereof, the system, however, having vacuum signal means for resetting the comparator to slowly eliminate the proportional action caused by the comparator.

Combined air and evaporator temperature control means for air conditioner apparatus

Abstract: In an air-conditioning apparatus, a single temperature sensor is used to control both room temperature and to prevent evaporator icing by mounting the sensor in heat conducting relation to the evaporator and in a path of airflow which parallels but bypasses the main stream of air through the evaporator

Method and apparatus for measuring the carbon potential in gas atmospheres

Abstract: A method and apparatus for detecting the carbon potential of a gas atmosphere within a heat-treatment furnace. A sample of gas atmosphere is extracted from the furnace and while cooling it the carbon deposit temperature is measured by a measuring element having of a carbon deposit detecting tip and a thermocouple adapted to be inserted directly into the furnace to measure the carbon deposit temperature of the said gas atmosphere. A temperature control means is connected with the carbon deposit detecting tip for changing the temperature of said tip, and a recorder is connected with said thermocouple for recording the temperature at which the tip detects a carbon deposit. The internal temperature of the furnace is measured, and the thus measured temperature values are used to determine the carbon potential.

Passive temperature sensor

Abstract: A passive temperature sensor for controlling a thermostat or the like. The sensor reacts to the temperature of the air and also to thermal radiation in order to control a thermostat in such a manner to give optimum personal comfort despite relative changes over a period of time between the room air temperature and thermal radiation effects in the room.

Turbine engine cycle temperature control system

Abstract: A turbine engine, provided with a fuel control, has a gasifier section and a free turbine power section with energizeable clutching means adapted for at least at times causing frictional engagement between the sections in order to vary the then existing temperature within a selected point of the engine to cause that temperature to change to a value consistent with prescribed limits for that temperature.

Heat-responsive temperature control device

Abstract: An improved heat-responsive temperature control device used for electric blankets, electric carpets and the like in which the reliability thereof is improved and the radio interference thereby is obviated by performing nonmechanical contacting temperature control and zero-voltage switching of the heater.

Refrigerator thermostat and arrangement thereof

Abstract: A temperature control device for use in a frozen-foods compartment of a refrigerator, or the like comprises a pair of temperature-sensitive elements one of which is adapted to be inserted into the material to be frozen. The two elements are connected in a logic circuit which in turn controls a switching device to thereby control the operation of the refrigeration unit to establish and then maintain a desired temperature in the compartment.

Apparatus and Method for the Control of Thermal E.M.F. in a Machine Tool

Abstract: 1,190,072. Testing materials. R.A. BILLETT. May 28, 1968 [March 6, 1967], No. 10394/67. Heading G1S. [Also in Division G3] In an apparatus to control the temperature of a tool on a machine the E. M. F. generated at the interface between the cutting tool and the workpiece, or a signal dependent on the actual tool temperature, compared with a reference, the error varying the cutting speed or feed drive of the machine to maintain the temperature constant. The error signal may vary the speed of an electric motor through a thyrisitor control arrangement, adjust a change speed mechanism such as a Kopp variator, or may control the admission of fluid to a hydraulic system. The tool temperature may be sensed by a thermocouple. The arrangement may be utilized as a method of testing the machinability of material by operating on a workpiece of the material until steady state conditions are achieved, and using the temperature control system as a measure of the machinability of the material. Pneumatic control of the driving mechanism is envisaged in the Specification. Where electrical control is utilized a relay may be employed to cut off any error signals below a determined value.

A Flexible Simple Thermostat for Small Objects and the Range of 100 to 400 K

Abstract: A flexible, inexpensive thermostat for the temperature range 100 to 400 K is described. Liquid nitrogen is the coolant and a gas serves as transfer medium. The temperature can be set to better than 1 K and is held there within ½ K by an electronic control system. The relatively small working volume of the order of 10 cm3 allows quick changes of temperature, a desirable feature in typical semiconductor experiments.

Thermocouple bridge temperature control

Abstract: A linearly calibrated temperature control suitable for economical commercial manufacture employs a thermocouple as an element of an arm of a Wheatstone bridge of particular resistance relation having a high-gain operational amplifier as the DC unbalance detector. The control temperature is varied by manual variation of resistance of a bridge arm and variations of amplifier offset are compensated at all temperatures by single-temperature scale adjustment. The DC output of the operational amplifier controls a power regulation circuit which responds to unbalance of one polarity.