Showing papers on "Temperature control published in 1987"

Method and apparatus for introducing a fluid into a human or animal organism as well as method and heating device for temperature control

Abstract: Process and device for introducing a physiological fluid at a prescribed temperature in human and animal organisms. The fluid is pumped through a regulated heating means (59) into a gravity-feed container (95), then led by natural gravity out of the gravity-feed container (95) through the same heating means (59) into the organism. While the fluid is being pumped into the gravity-feed container (95, the temperature of the fluid entering the heating means (59) is measured and on the basis of the temperature measured the heating means (59) is set to a temperature or a corresponding heat flow which produces essentially the prescribed temperature of the fluid leaving the heating means (59). While the fluid is being led by natural gravity, the temperature of the heating means (59) is regulated until the prescribed temperature of the fluid is obtained. A heating means (59) suitable for this device comprises at least two heating lateral walls (28, 128) and a channel (47) passing between them. Each side wall (28, 128) has a heating resistance net and a temperature sensor. The resistance network is composed of a heating foil pattern (2, 102) formed on the side of an electrically isolating base plate (1, 101) facing the medium to be heated. On the other side of the base plate (1, 101) is formed a sensor foil pattern (3, 101) forming a temperature sensing resistance and covered with an isolating layer (15, 115).

Thermostat control system

Abstract: A microcomputer-controlled thermostat for use in monitoring and controlling a single zone HVAC system which provides conditioned air to one or more zones. The thermostat can be programmed and used either as a monitor thermostat to control the HVAC unit alone and/or to control the HVAC unit and its damper in a multiple zone mode. The thermostat is also programmed as a slave thermostat in a master-slave relationship with a monitor thermostat. The microcomputer memory is supplemented with additional ROM containing control algorithms for use in system operation. Logic circuitry is used to recognize commands as being for operation of the HVAC unit, the operation of the damper, or selection of which systems sensors are to be enabled. A real time clock circuit in the monitor thermostat is used to supply data for time-based system operation.

Gas sensing instrument

Abstract: A gas sensing instrument provides programmable control of the operating temperatures of an array of gas sensors for the detection of target gases in air. The control facilitates precise temperature setpoint resolution. The gas sensors in the array have an improved construction density with reduction in size and an extended operating life provided by reduced power consumption. A programmable circuit functions as a programmable-resistor temperature controller in a Wheatstone bridge configuration. A multiplying digital to analog converter circuit controls the ratio of voltage to current that functions as a resistance equivalent. The programmable circuit is interfaced with a computer to provide selectable temperature control for at least 256 setpoints.

Temperature variable long path cell for absorption measurements

Abstract: The design and construction of a long path cell for absorption measurements at temperatures ranging from 215-470 K and at pressures from vacuum to 10 atm are described. The cell consists of three concentric stainless-steel tubes; the innermost tube is 6.5-in. in internal diameter, has a volume of about 47 l, and contains White-type optics, six thermocouples, and a gas input tube; and the outermost tube provides a vacuum Dewar around the inner assembly. The optical design and temperature control system for the long path temperature variable cell are examined. The long path cell is applicable for analyzing temperature and pressure dependence of spectra and reaction rates of gases, and the cell has flow and photolysis capabilities for studying transient species and photochemically initiated reactions. A diagram of the cell is provided.

On temperature compensation in hot-wire anemometry

Abstract: The temperature sensitivity of a constant temperature, hot-wire anemometer has been experimentally investigated over a large range of ambient temperatures (22-98 degrees C) and for a low range of velocities (0.35-9 m s-1). From the large number of methods proposed in the literature for compensating the velocity reading of a hot-wire anemometer for temperature fluctuations in the flow, five different analytic approaches have been applied to the experiment data. Limitations and errors using the various methods are systematically examined. The most consistent compensation has been obtained using the relationship proposed by D.C. Collis and M.J. Williams (1959) in which fluid properties are evaluated at the mean film temperature.

Status indicator for self-energizing burner control system

Abstract: A self-energizing burner control system for a fuel burner is accomplished by heat from a pilot flame energizing a thermoelectric generator. The thermoelectric generator supplies power to an oscillator. The oscillator has an output that is stepped up in voltage level and is converted to a regulated direct current potential. The regulated direct current potential in turn is used to operate a solid state temperature control or controller. This controller has a sampling rate that is visually indicated by a light emitting diode when a proper voltage is present. The system further insures that a temperature sensor is in place, and is functioning properly.

Control of rf answer pulses in a tv answer back system

Abstract: In a TV answer back system where many receiver stations communicate with a TV transmitter station by means of rf pulses generated by rf oscillators at the receiver station, the requirement for keeping all oscillators on frequency is achieved without crystal temperature control by automatically controlling the rf oscillator frequency using synchronization signals carried in the video signal received from the TV studio. By this invention it has been possible to control the frequency of multiple megahertz oscillator as accurately as desired from relatively low frequency synchronizing signals such as the vertical and horizontal video sync pulses. Thus an oscillations counter is gated for a very accurate time period by the sync pulses, and the oscillation count is compared with a datum count representing the desired oscillation frequency. The requirement to prevent receiver stations from answering with rf pulses in response to queries contained in home video recordings of previously broadcast signals is achieved by encoding broadcast time on all query containing TV transmissions, and by comparing at receiver stations broadcast time information from received signal with time from a local battery backed clock contained at each receiver station, thus discrimination of video recordings is possible by comparing received video broadcast time with local time.

Duct type air conditioning system

Abstract: An air conditioning system provided with a variable capability blower and heat source unit is configured such that individual room dampers 9 and controllers 14 can be subsequently added to a central control device as options to convert from an all room simultaneous air conditioning mode to a variable air volume mode with separate temperature control for each room. The utilization of existing power lines to transmit the various information and control signals simplifies the conversion and reduces its cost.

Temperature control system for cooking apparatus

Abstract: A temperature control system for cooking apparatus, for example, a fryer using cooking oil or shortening which is heated by a suitable heating element. The cooking apparatus has different modes of operation including start-up mode, idle mode and cooking mode. Overshoot to a temperature above the setpoint temperature is limited during start-up mode, idle mode and cooking mode with the apparatus having different temperature control characteristics based on the mode of operation and adapting variable parameters to achieve optimum temperature control accuracy.

Temperature control system using a single ramp rate curve for control of a multiplant environmental unit

Abstract: A temperature control system for a multiplant environmental unit such as a heat pump with auxiliary heat is disclosed. The control system utilizes a thermostat having a microprocessor and memory that allows for energy savings through setback functions. The setback functions return the temperature control from a setback temperature to a normal comfort temperature along a ramped rate that is modified from day to day. The purpose of this variable ramp is to minimize the operation of the auxliary heat and maximize shell savings (by starting as late as possible). This is basically accomplished by locking the heat pump on in certain cases.

Control for batch mixers

Abstract: The invention relates to a process for mixing a polymer composition using an internal mixer having rotors 18, 20 rotatably mounted in a chamber 12, a ram 28 by which pressure can be applied to material in the chamber 12, and temperature control means for the mixer. Materials are introduced into the chamber 12 and, after introduction of all the materials, at least three mixing variables e.g. temperature, time and energy, indicating mixing quality are monitored and control variables e.g. rotor speed and/or ram pressure adjusted dependent on the monitored mixing variables to achieve previously defined targets or if all are not simultaneously achievable, the most significant target. Control is initiated when the ram has reached a predetermined position and when at least one preselected condition e.g. time, temperature or energy, has been achieved. The mixer comprises a computer 44 effecting the control and arranged to heuristically derive relationships between control and mixing variables by which the process is controlled.

A constant temperature hot-wire anemometer

Abstract: A constant temperature anemometer is described which is designed to operate hot wires with diameters in the range 0.63-5 mu m. A special feature of the design is the use of separate current sources to supply the different halves of the bridge. This feature eliminates the need for dynamic stability compensation, necessary for commercial constant temperature anemometers. The frequency response of the present circuit compare favourably with that of a commercial circuit. The probability density and spectral density functions of the longitudinal velocity fluctuation, obtained with wires of different diameters, are in good agreement with those obtained with a commercial circuit.

Galvanneal induction furnace temperature control system

Abstract: An induction galvanneal strip furnace utilizes a plurality of radiation (infrared or optical) pyrometers which measure strip temperature and provide a feedback signal which is compared with a set point or reference temperature signal from a set point generator to produce an error signal proportional to the measured variable minus the set point or reference temperature. The error signal is processed by use of a conventional proportions integrator derivative algorithm to produce a control signal which controls the electrical energy supplied to the induction coils. Each of the radiation pyrometers is positioned at the emergence or downstream side of the downstream most induction coil of a set of induction coils that it controls to thereby provide rapid, accurate control of strip temperature and with a more efficient utilization of electrical energy and high quality in the finished product. As compared to gas fired furnaces, the speed of the strip through the furnace of this invention can be increased 25 to 30 percent.

Temperature control system for control of a multiplant environmental unit

Abstract: A temperature control system for a multiplant environmental unit utilizing a heat pump and auxiliary heat is specifically disclosed. This system is operated by a microcomputer based real time operated thermostat which provides night setback and day setup in an energy efficient manner. The efficient operation is accomplished by having separate heat pump and auxiliary heat ramp rates that can be operated together in parallel in a first mode of operation, and operated separately in a second mode of operation.

Method and apparatus for generating isotherms in a forehearth temperature control system

Abstract: A technique for generating isotherms representing the cross-sectional temperature profiles of molten glass (17) flowing in a forehearth channel (20). A plurality of temperature sensors (21-29) are placed at predetermined locations within the plane of the channel cross-section, advantageously in a rectangular grid, to provide a matrix of temperature readings. Digitalized temperature readings from these sensors are routed to a processor (53), which interpolates these temperature readings to approximate the temperature intermediate the various sensing points, and optionally beyond the array of sensing points. The isotherms are obtained by fitting a Legrangian interpolating polynomial through the various recorded temperatures. The interpolated values thus generated may be used to provide real time displays of isotherms in the forehearth cross-section under examination, or may be included in a control loop.

Modeling and control of the wafer temperatures in a diffusion furnace

Abstract: In this paper the thermal behavior of a diffusion furnace is studied. The ultimate goal is to achieve control of the wafer temperatures. It is shown how some previous results from the literature on the behavior of wafer temperatures in a diffusion furnace are incomplete and partly erroneous. A control algorithm has been derived which achieves much better wafer‐to‐wafer uniformity than conventional control.

Method for controlling the temperature of the coolant of internal combustion engines

Abstract: A temperature control device for the cooling water of internal combustion engines is proposed, which in the feed line and bypass line has a control valve, which can be actuated by means of a servomotor as a function at least of the coolant temperature. This is kinematically connected to the valve rod of the control valve. The servomotor is controlled as a function of a sensor, which measures the coolant temperature in a line connected to the engine. The sensor is provided with an external heating device on a housing part situated outside the line. The heating device can be switched on and off as a function of engine characteristic variables. On switching off, the sensor is very rapidly recooled by the coolant in the line and the control valve thereby returned.

System control means to preheat waste oil for combustion

Abstract: An apparatus and method for a system control means to control the temperature and preheat of waste oil in a waste oil feed system and burner. The apparatus and method include the combination of a heat transfer assembly with a helical passageway through a preheat means, a system control means, an anticipatory rate-proportional band temperature control means, and an expansion pressure relief means.

Control unit for electronically controlling the hob temperature with a temperature sensor

Abstract: The invention relates to a control unit for electronically controlling the hob temperature with a temperature sensor, which can be used for single hot plates (rings) and ceramic glass hobs, since the control unit is designed in such a manner that the evaluation circuits arranged in the control unit can be upgraded according to use. The control unit according to the invention for solving this problem is characterised in that evaluation circuits for a hob temperature control, a heat capacity detection, an excess temperature protection, and a residual heat volume display are arranged in the control unit which is controlled by the temperature sensor.

Air conditioner for automobiles

Abstract: An automobile air conditioner includes a duct interconnecting a blower unit and a temperature control/air distributing unit having a pair of cooling and heating heat exchangers, the duct having a cross-sectional area gradually increasing toward the temperature control/air distributing unit. The air conditioner preferably has a hot/refrigeration compartment disposed in juxtaposition with the duct. In a preferred embodiment, the air conditioner includes a hot air control mode door for controlling a stream of hot air flowing from the heating heat exchanger toward an upper air outlet and a lower air outlet.

Differential temperature control

Abstract: The difference between the zone temperature and the scheduled setpoint, or Δt, is the basic data from each zone. Communication between the air handler control and the air terminal control is provided via the air system control so that the system is temperature, rather than pressure, responsive.

Method and apparatus for temperature control of heating and cooling plants

Abstract: The present invention relates to a method and an apparatus for controlling the temperature of heating and cooling plants having a heat or cooling source of adjustable rated temperature via particularly a microprocessor-controlled control system. The actual outside temperature determined by an outside temperature sensor is not used as reference temperature but instead there is used a theoretical mean outside temperature stored at specific scanning times of a calendar year. Said theoretical mean outside temperature is stored in the form of a characteristic diagram in a non-erasable memory for one or several climate zones. By correction of the stored values of the theoretical mean outside temperature particularly on the basis of the thermal load of the system determined via the rate of heating or cooling of the heat or cooling source as well as perhaps the correction of the daily course of the outside temperature on the basis of likewise stored values the rated temperature of the heat or cooling source can be so controlled that it corresponds to the actual outside temperature conditions without requiring an outside temperature sensor. With regard to its construction, installation and putting it into operation as well as from the economic point of view the apparatus is particularly advantageous.

Self-cleaning oven temperature control with multiple redundant oven temperature sensing elements

Abstract: An electric range having a self-cleaning oven utilizes a digital electronic microprocessor based oven temperature control system having multiple, redundant oven temperature sensing elements. The output signal from a first one of the multiple oven temperature sensing elements disposed in the cavity of the oven is used as a primary sensed bake temperature signal for controlling the temperature of the oven during its BAKE mode of operation and as a redundant or back-up sensed clean temperature signal for safely shutting down the oven during its CLEAN mode of operation in the event that the sensed oven temperature significantly exceeds the top of the clean temperature range. Correspondingly, the output signal of a second oven temperature sensing element is used as the primary sensed clean temperature signal for controlling the operation of the oven during its CLEAN mode of operation and as a redundant or back-up sensed bake temperature signal for safely shutting down the oven in the event that the sensed oven temperature during the BAKE mode of operation significantly exceeds the top of the bake temperature range. Oven temperature sensing proves associated with the above two temperature sensors may be individually mounted in separate housings in the oven cavity or may be mounted in a single sensor housing in the oven cavity where space or mounting considerations are particularly acute.

Method of operating a transport refrigeration system having a six cylinder compressor

Abstract: A method of operating a transport refrigeration system having a six cylinder compressor and a prime mover operable at a selected one of low and high speeds, to control the temperature of a served space by cooling and hot gas heating modes. Below a set point temperature 100, system heating capacity is controlled at the low compressor speed by the step 127 of unloading compressor cylinders and the step 129 of reloading compressor cylinders. A temperature rise of the served space above a set point temperature 106 controls cooling capacity by a combination of alternative steps 135, 137, 139, 141, and 143 which may or may not change the number of loaded compressor cylinders, and may or may not change compressor speed, based upon two predetermined trigger events which relate to what the temperature of the served space does relative to time 136 and 142, a set point temperature 106, and a temperature 108 above set point which is normally associated with a change in compressor speed.

Temperature control apparatus for vehicular catalytic converters

Abstract: A temperature control apparatus for at least two catalytic converters which are connected in series in an exhaust passage of an internal combustion engine mounted on a vehicle. A by-pass is disposed in parallel with a first catalytic converter which is connected in the vicinity of the engine. Valve drive means serves to drive a control valve for controlling the ratio between the amounts of exhaust gas introduced into the first catalytic converter and the by-pass. Control means serves to calculate the deviation between a reference value and a temperature value, which is associated with the catalyst-bed temperature of the first catalytic converter, and is detected by temperature detecting means, and to deliver a drive signal to the valve drive means in accordance with the deviation, thereby controlling the opening of the control valve. Immediately after the start of the engine, therefore, the catalyst-bed temperature of the first catalytic converter rises to the reference temperature value for an optimum purifying efficiency. Thereafter, the bed temperature is kept constantly in the vicinity of the reference value.

Radio-linked automatic climate control system for motor vehicle air-conditioning

Abstract: An electronic system to keep the set air temperature inside a motor vehicle constant It comprises an electronic thermostat, a radio transmitter to transmit the on/off signals of said thermostat, a radio receiver to capture said on/off signals which will drive a switching circuit 10 to turn on/off the vehicle air-conditioner, and a time delay network 9 to delay the on/off actions of said switching circuit Said electronic thermostat comprises a temperature sensing circuit 1, a temperature setting circuit 2, a humidity sensing circuit 3 to compensate the set temperature, a comparator 4 to compare the two output voltages from said temperature sensing circuit and said temperature setting circuit, and a switching circuit 5 to turn on/off the transmitter The thermostat and the transmitter are packed together and installed on the motor vehicle dashboard The receiver and the time delayed switching circuit are packed together and installed under the hood of said motor vehicle The system requires no skill and no tools for installation, can extend the air-conditioner life and save the fuel consumption up to 90% over the other existing automatic or manual temperature control systems for motor vehicle air-conditioning

Paper temperature measurement fuser control

Abstract: A fuser temperature control in a machine having a first temperature sensor contacting a fuser roll surface, a prefuser transport for conveying copy sheets to the fuser, a controller and a second sensor electrically connected to the first sensor and positioned adjacent the path of said copy sheets to sense the temperature of the copy sheets and the ambient temperature of the machine at the entry to the fuser, wherein the fuser roll temperature is controlled in response to variations in the ambient temperature at the pre-fuser transport and the temperature of the copy sheets.

Review of cryogenic heat pipes in spacecraft applications

Abstract: WITHIN three years after the first technical article on heat pipes,1 the results of an experimental investigation that used nitrogen heat pipes to control the temperature of an infrared detector were published.2 Since that time, the use of cryogenic heat pipes has increased steadily. Most of the investigations involving low-temperature heat pipes have been focused either on space applications involving the cooling and thermal control of optical surfaces3 or infrared scanning systems,4 or on the thermal control of large superconducting magnets.5 Small thermal gradients in optical surfaces can result in dramatic variations in the wavefront quality and pointing accuracy of the optical element. These thermal gradients can and have been successfully controlled through the use of heat pipes, such as those used on the Orbiting Astronomical Observatory6 launched in the early 1970s. In this type of application, heat pipes are utilized to maintain the optical surface at a constant temperature and hence improve the optical quality. In satellite infrared scanning systems, heat pipes are used not only to eliminate temperature variation but also to remove heat from both the infrared detectors and the aperture shroud. These devices must be cooled to a temperature ranging from 5 to 120 K. In the detector, this low temperature provides greater resolution, while in the aperture shroud it helps eliminate background radiation or "thermal noise." These two applications along with others such as electronic cooling have resulted in a renewed interest in the operation and use of cryogenic heat pipes for thermal control,7'8 particular in zeroor reduced-gravi ty environments.

Temperature control arrangement for an extruding process

Abstract: An arrangement for controlling the process temperature in an industrial process involving an extruding operation includes a summing element which sums the difference between the process temperature and a setpoint temperature with the rate of change of the process temperature and conveys this sum to a proportional and integral controller so that the output thereof acts in an inverse manner with the process temperature. This output of the controller is summed with the change of temperature rate which has been fed forward, to generate a demand signal. The demand signal is shaped and compared to a ramp waveform to generate a variable frequencey pulse for controlling a heating and/or cooling device associated with the extruding device. A change of speed rate can also be summed to form the demand signal.

Compact pressure cell for light‐scattering experiments

Abstract: The design and construction of a unique and precision pressure cell suitable for use in light‐scattering experiments has been described. The cell has been adapted to allow scattering experiments from liquid samples. The optics of the cell has been especially designed to obtain a higher signal‐to‐noise ratio. The cell has been designed to be small and compact with sample volume ∼40 mm3. However, it still has a large heat capacity (∼250 J/K) which ensures easy and stable temperature control of the sample. The cell can sustain hydrostatic pressure up to 1000 bar and temperature up to 150 °C. When operated in the constant temperature and pressure mode it offers long‐time (∼16 h) temperature and pressure stability of ±2 mK and ±0.05%, respectively, in this entire range.