Abstract: The present invention discloses methods for determining setpoint information in a HVAC system. Setpoint values are determined using occupant feedback provided by individual occupants over at least one of an Internet or Intranet communications network. According to a first aspect of the invention a setpoint is determined using fuzzy logic. According to a second aspect, historical setpoint data determined using occupant feedback is used to develop a neural network for predicting setpoint values.

Abstract: The present invention is a voltage adapter for a low voltage thermostat which permits the following input voltage ranges:100-132 VAC/50 or 60 Hz,200-264 VAC/50 or 60 Hz, and265-330 VAC/50 or 60 Hzmaintaining an output of at or just effectively about 24 VAC.

Abstract: A method for controlling opening/closing of cool air discharge ports of a refrigerator is disclosed. The refrigerator has a device for opening/closing the ports. The device has a member for opening/closing the ports, and a motor for driving the member. A microcomputer measures temperatures at positions in a cooling compartment, and calculates a difference between the measured temperatures. When the difference is more than a predetermined value, the motor is driven so that the member repeats opening and closing of the ports. Then, the circulation effect of the cool air in the cooling compartment is enhanced, and the temperature in the cooling compartment maintained uniform.

Abstract: A programmed temperature controller including a difference detector which detects a temperature difference .DELTA.T between a quick-response temperature TC2 and a slow-response temperature TC3 at a quickly-responding portion and a slowly-responding portion of a workpiece (e.g., on the surface and core portions thereof). Also included is a comparator which compares the temperature difference .DELTA.T against an allowable difference limit preset by a difference setter. When the temperature difference .DELTA.t is found to be outside the allowable difference limit, a slope operator is actuated by the comparator, so as to calculate a slope of temperature change with respect to time of a program pattern PP which keeps the temperature difference .DELTA.t within the allowable limit. The above-mentioned slope in the program pattern PP is modified to the calculated value, and the temperature difference .DELTA.T is maintained within the allowable difference limit.

Abstract: A temperature controlling apparatus adopting a fuzzy adaptation model and a method using the same are provided, in which temperatures of a plurality of positions of a refrigeration compartment are estimated in order to rapidly reach temperature equilibrium of the refrigeration compartment, by considering the operation states of a compressor and a cooling fan which directly affect the temperature of the refrigeration compartment. The temperature controlling apparatus adopting the fuzzy inference includes: a cool air discharge direction controller for controlling the rotation angle of a cool air discharge control blade; and a fuzzy inference unit for inferring peripheral temperatures of temperature sensors by taking the operational states of the cooling fan and the compressor as inputs, in order to provide the cool air discharge direction controller with information with respect to the static angle of the blades of the cool air discharge control blade.

Abstract: A method for controlling the temperature of a compartment of a refrigerator, the compartment utilizing at least two spaced apart temperature sensors, such that, even when one of the sensors malfunctions, the compartment is cooled without any degradation of efficiency. The sensors detect respective temperatures in the compartment. While the sensors are operating normally, the detected temperatures are stored. In the event one of the sensors malfunctions, an abnormal average temperature is calculated using: (i) previously stored temperatures of the abnormally operating sensor, and (ii) a temperature recently detected by the normally operating sensor. Thereafter, the calculated abnormal average temperature is compared with a reference temperature to control the operation of a fan.

Abstract: A chiller having a forced air means and a pressure plenum so as to provide a suitably concentrated and even air flow and distribution through spatial gaps between trays on one or more insertable food racks. The plenum has a high pressure cavity at one end and a low pressure cavity at the opposite end. A motorized fan mounted above the plenum and separated therefrom by a ceiling plate draws chilled air from the low pressure chamber and forces it into the high pressure chamber in front of the plenum. A turning vane directs the air into high pressure chamber and reduces potential turbulence. The walls leading from the high pressure cavity to the plenum are preferably tapered at least in part so as to force air into the plenum in a funnel-like manner, and uniformly through spatial gaps between the trays on the rack or racks. A multi-function controller controls the chilling operation by allowing selection of either a chill time or a target product temperature.

Abstract: An apparatus (10) for cooling and tempering bacon slabs supported upon wheeled trucks (24) which can be rolled on the floor (14) inside a cooler (12) includes an evaporator (26) having multiple fans (34) for moving air through refrigerated coils (32) and in the cooler (12). Moisture collecting on the refrigerated coils (32) drops into a drain pan (30) and is drained through pipes (38) outside the cooler (12). The fans (34) are alternately rotated in opposite directions for equal time segments and baffles (40) are provided inside of the cooler (12) to assure uniform air chilling. A controller (46) operates the evaporator (26) so that the air inside of the cooler (12) is cooled to a temperature less than the internal product temperature which is greater than freezing and specifically in the preferred form at a desired temperature differential of 20.degree. F. (11.degree. C.) until an intermediate internal product temperature is reached.

Abstract: A thermostat includes a first temperature sensor integral with the thermostat and at least one and typically three remotely positioned temperature sensors. Switches are provided to select which one or more temperature sensors are employed to provide an averaged measured temperature. Voltages representative of the temperature ambient to each diversely placed sensor are applied to separate inputs to an analog multiplexer which transfers a single voltage to an analog-to-digital converter in accordance with address codes received from a processor. The output of the A-D converter, a digital count representative of the temperature measured by the currently selected sensor, is read by the processor and temporarily saved. Then, the next selected sensor is similarly processed.

Abstract: A temperature program pattern PP for desired change of surface temperature TC1 of a work 11 with time is set by a temperature setter 31. Work temperature-difference .DELTA.t.sub.pv between the surface temperature TC1 and inside temperature TC2 of the work 11 is determined by a difference detector 34. Set value of the above temperature-difference .DELTA.t.sub.sp is given by a difference setter 35 in the form of a difference pattern DP of its change with the above surface temperature TC1. For each actual surface temperature TC1, the work temperature-difference .DELTA.t.sub.pv is compared against its set value on the difference pattern DP by a comparator 36. A slope operator 37 responds to the output from the comparator 36 and modifies slope of the temperature program pattern PP so as to cause the work temperature-difference .DELTA.t.sub.pv to follow the difference pattern DP.

Abstract: A thermostat for heating or cooling, operative to maintain an indoor air temperature to a limited setpoint range, is provided with a comparison circuit to prevent tampering intended to exceed a setpoint limit. A first temperature sensor responds to ambient air temperature and can include a first thermistor. A second thermistor is partly thermally isolated from the air, and senses a reference temperature that lags temperature changes in the ambient air. The two thermistors form a voltage divider coupled to one input of a differential amplifier comparator, the other input of which is coupled to a fixed voltage reference. When the ambient and reference temperatures exceed a predetermined temperature difference, the differential amplifier operates a relay that breaks a circuit including the contacts. This occurs when locally cooling the ambient air to generate a spurious call for heat (or vice versa).

Abstract: Merchandise temperature sensors 16 for detecting merchandise temperatures simultaneously with in-housing temperature sensors 17 for detecting the in-housing air temperature of a merchandise housing are provided in the merchandise housing of a vending machine. Further, the cooling mechanism is controlled by means of the merchandise temperature sensor 16 during the peak shift or peak cut, whereas the cooling mechanism is controlled by means of in-housing temperature sensor 17 during normal operation. Thus the merchandise temperature is directly detected during the peak shift or peak cut where the temperature sharply varies so as to increase merchandise temperature control accuracy. Even when the installation of the merchandise temperature sensors is limited to some columns in view of cost reduction, the cooling mechanism is made controllable by collectively detecting the merchandise temperature in the whole column by means of the in-housing temperature sensors 17 during the normal operation.

Abstract: A thermostat has terminals to receive at least two temperature sensor signals, and changes the one of these terminals which provides the feedback signal for temperature control responsive to a detected condition. This condition may be a manual input, expiry of a time interval, reaching a time of day, or the relative magnitudes of the temperatures encoded in the sensor signals.

Abstract: An air conditioner comprises a heat exchanger for conducting refrigerant in heat exchanging relationship with an air flow, and a blower for drawing air through the heat exchanger. An adjustable flow distributing plate is disposed between the heat exchanger and blower and is movable by a motor to various positions for controlling the relative air flows through respective portions of the heat exchanger. Temperature sensors are connected to the heat exchanger for detecting the refrigerant temperature at various regions of the heat exchanger. The adjustable plate is positioned in a desired position in response to the detected refrigerant temperatures for equalizing the refrigerant temperatures in the regions of the heat exchanger.

Abstract: A temperature control system for a building structure such as a household is divided into a plurality of zones. A controller acts between temperature sensing devices in each of the zones and an adjustable thermostat which allows the desired temperature in the building structure to be selected. The controller allows individual zones to be selected to receive conditioned air and allows one of the selected zones to be designated as a control zone. A heating or cooling decision for the temperature control system for all of the selected zones is made based on the difference between the thermostat setting and the output of the temperature sensing device in the control zone. The control zone can be changed manually to the next available selected zone. Different visual indications are given for the control zone and the selected zones. Zones with faulty temperature sensing devices cannot be control zones or selected zones.

Abstract: An air conditioner includes a comprising temperature regulator for regulating air temperature in a room, a circulating mechanism for circulating the temperature regulated air, a first room temperature detector for detecting room temperature in a set location in the room, a second room temperature detector for detecting room temperature in a location lower than the first room temperature detector, and a controllor for controlling the temperature regulator in accordance with outputs from the first and second room temperature detectors so as to efficiently equalize indoor temperatures and reduce energy consumption.

Abstract: A control system for effecting ultra-precision temperature control for a controlled system having large load fluctuations or including a dead time component. A control unit (5) instructs a high-precision PID temperature controller (10) to renew and correct a control target value T.sub.0,NEW for the supply fluid temperature T.sub.0 only by a temperature difference .DELTA.T=T.sub.C -T.sub.2 between a set value T.sub.C for the return fluid temperature T.sub.2 of a heat transfer fluid and the actually controlled return fluid temperature T.sub.2. In response to the instruction, the high-precision PID temperature controller (10) controls the heating power of a heater (17) for heating control through a constant-power thyristor phase controller (16). The heater (17) heats the heat transfer fluid and sends it to a machining apparatus (1) through a closed damping tank (21). The heat transfer fluid exchanges heat with the machining apparatus (1) and is then returned to a precooling means.

Abstract: The residential structure ventilating apparatus disclosed herein employs a variable speed exhaust fan. The speed is responsive to a sensor which detects air temperature at the exhaust port. The fan is energized when the sensed air temperature rises above a first preselectable temperature and the external environmental air is cooler that the air at the exhaust port. The fan speed is increased progressively from about one-half full speed at the preselected turn on temperature to full speed at a predetermined higher temperature. The fan is turned off when the exhaust port temperature falls below a second preselected temperature, lower than the first preselected temperature or when the external environmental temperature rises above the inside temperature, the fan speed being essentially constant between the first and second preselected temperatures.

Abstract: A cooling abnormality detection system for external electronic equipment includes a protection unit. The protection unit includes two temperature sensors arranged in each piece of external electrical equipment to be monitored, in order to measure the temperature of each. A temperature difference measuring means receives the measured temperature from each piece of equipment and outputs a sensor failure signal when the absolute value of difference between the temperatures measured by the two temperature sensors exceeds a first predetermined value. An abnormal temperature signal is output from the temperature difference measuring means when the two measured temperatures both exceed a second value. The sensor failure signal is transmitted to the electronic equipment, while generation of the abnormal temperature alarm interrupts the power supply to the electronic equipment.

Abstract: An apparatus accurately controls output water temperature of an instantaneous water heater to maintain a desired outlet temperature. A first electronic sensing device senses a flow of water through the heater, and an ignition sequence commences when flow has been detected. A second electronic sensing device senses an outlet water temperature of the heater, and a third electronic sensing device senses a midway water temperature of the heater. The burner output or outputs are controlled to maintain the desired outlet temperature, based on changes in water flow and incoming water temperature. With multiple burners, the burner outputs are staged to accurately control the output water temperature of the instantaneous water heater to maintain the desired outlet temperature.

Abstract: An air conditioner for railway vehicles controlled in accordance with the air temperature in the car and data on at least one selected from the group consisting of underfoot temperature, radiant heat, air flow, humidity, outside air temperature, number of passengers and door opening operation. In this way, environment conditions which momentarily change are detected so as to prevent excessive cooling or heating in the car.

Abstract: A computerized control system for use in a deep fat fryer is provided for controlling a heating device and a temperature probe added to the deep fat fryer whereby both the heating device and temperature probe are located in proximity to the bottom zone of the cooking vessel of the fryer. The computerized control system thereafter regulates the temperature of the portion of the cooking substance located in proximity to the bottom zone of the vessel to a predetermined target temperature range. By doing so, moisture found within any cracklings located within the bottom zone of the vessel is minimized and the cooking substance therefore will not boil over the sides of the vessel.

Abstract: An averaging temperature probe is disclosed wherein a sensor strip extends from a mounting plate substantially across a stratified airflow. Temperatures at points spaced along the sensor strip are measured and averaged by circuitry to provide a more accurate representation of the actual or mixed airflow temperature.

Abstract: An embodiment of the present invention is a temperature forcing system and method for precision temperature control of a device-under-test. The system comprises a thermal test head suspended by a support arm that receives a temperature controlled air flow through an output hose from an air supply system. A pair of temperature sensors, one attached to the device-under-test and the other in the output hose, are used differentially by a closed-loop temperature controller when the temperature of the device-under-test comes within a temperature window surrounding a target temperature setpoint point. Outside the temperature window control is linear and within the temperature window control is compensated by a correction factor obtained during a single calibration test that amalgamates the effects of the mass of the device-under-test, the ambient conditions and other factors.

Abstract: A parameter estimation system (16) automatically determines the relevant thermal and thermodynamic parameters which govern the energy consumption of the climate control system (18) within an enclosure (30).

Abstract: A temperature control apparatus for a machine tool includes four temperature sensors for detecting a reference temperature, outlet temperature of heat transfer fluid at an outlet of a heat exchanger, and temperatures of the heat transfer fluid at both inlet and an outlet of a machine tool element having a heat generating source. The four temperature sensors are arranged to constitute a differential temperature detecting means that activates control means to control temperature of the heat transfer fluid from the heat exchanger so as to minimize both deviations of heat transfer fluid temperature and steady-state deviations of machine tool body temperature.

Abstract: Method and apparatus are provided for establishing and controlling the stability and movement of a reaction wave of reacting gases in a matrix of solid heat-resistant matter. At least a portion of the bed is initially preheated above the autoignition temperature of the mixture whereby the mixture reacts upon being introduced into the matrix thereby initiating a self-sustaining reaction wave, after which, the pre-heating can be terminated. The stability and movement of the wave within the matrix is maintained by monitoring the temperatures along the flowpath of the gases through the bed and adjusting the flow of the gases and/or vapors or air to maintain and stabilize the wave in the bed. The method and apparatus provide for the reaction or combustion of gases to minimize NO.sub.x and undesired products of incomplete combustion.

Abstract: A method for providing uniform temperature in a furnace, such as a soaking pit or a reheat furnace is disclosed. Temperatures at a front wall and a burner wall within the heating chamber are constantly monitored by a computer, and the computer operates a direct-fired burner, or for example, a pair of regenerative burners, in one of two modes to place heat either at the front wall or the burner wall. The burner is oversized in relation to a maximum firing rate required by the heating chamber design. To heat the front wall, an impulse firing mode is initiated by the computer wherein the burner is fired at its full, overrated capacity for a time proportionally less than a normal firing cycle. To heat the burner wall, the computer initiates a proportional firing mode wherein the burner is fired for the full normal cycle, but at a rate which is equivalent to the actual firing rate demand calculated by the computer.

Abstract: A system for controlling vehicle passenger compartment comfort. An electronic controller receives input from: (i) a thermistor array sensing blower plenum discharge temperature, (ii) a user movable Level Select Control (iii) a potentiometer sensing the position of a servo driven heater core water valve, (iv) an engine rpm tachometer generator and (v) a blower speed signal. The controller employs proportional-integral-derivative (PID) strategy in a microprocessor to generate a control signal for operating the heater core valve servo motor to maintain the plenum discharge air at a constant temperature irrespective of wide swings in engine rpm/water pump speed or user selector changes in blower speed.

Abstract: A thermal reactor, and a method of operating the thermal reactor, in which the thermal reactor includes: a chamber which is thermally isolated by refrigerated air circulating in the walls of the chamber, and which holds a tray of sample vials; means for supplying air to the chamber and for exhausting air from the chamber; heaters for heating the air supplied to the chamber; sensors for sensing the temperature of the air supplied to the chamber and of the sample vials, and a computer which pulses the heaters according to the measured temperatures of the vials and the air in the chamber to maintain the temperature of the vials at a desired level.

Abstract: A hydraulically supported roll includes a stationary crosshead extending through a rotatable hollow roll, which is heated at its inner and outer circumferences. A thermostatic control and regulating device is provided to keep the temperatures at the inner circumference and the outer circumference of the hollow roll at the same level during the heatin-up and/or cooling-down phase.

Abstract: A heater comprising a heater body containing a heating source; an air blower for forcibly blowing off heated air from the heater body into a room, the heated air being produced by heat-exchanging with the heating source; a first temperature detection element for detecting a temperature at an upper level in the room; a second temperature detection element for detecting a temperature at a lower level in the room; a sensation input means for enabling a user to input his or her sensation corresponding to an actual room temperature; means for determining heating capability of the heating source based on the difference between the temperature detected by the first temperature detection element and a first set temperature; means for changing the outlet area and/or the air volume of the heated air based on the difference between the temperature detected by the second temperature detection element and a second set temperature lower than the first set temperature to determine the blow-off speed and/or the air volume of

Abstract: To reduce the heat present in hot hydraulic oil, the oil is passed through a heat exchanger in heat exchange relation with water. The temperature of the water entering the exchanger is at least 28.degree. C. and the quantity of water circulated through the exchanger is such that the difference between the ingoing and outgoing temperatures of the oil at the heat exchanger is not more than 10.degree. C.

Abstract: The delivery side of a refrigerant compressor is connected through an inside heat exchanger to a refrigerant heater, the outlet side of the refrigerant heater being connected with the suction side of the compressor. First and second temperature sensors are provided at inlet and outlet sides of the refrigerant heater, respectively for sensing inlet and outlet refrigerant temperatures. A fuel gas supply unit for the refrigerant heater is fitted with a fuel gas control value which is controlled by the temperature differences existing between sensed temperatures by the first and second sensors.

Abstract: A control device for an air conditioner including a compressor driven by an inverter is disclosed. The control device comprises a floor temperature sensor as well as a room temperature sensor for detecting representative room temperature. A standard operation frequency of the compressor is determined on the basis of the difference between the target temperature and the representative room temperature detected by the room temperature sensor. Adjustment is made to the standard operation frequency according to the difference between the temperatures detected by the two temperature sensors, thereby obtaining an operation frequency of the compressor.

Abstract: A thermoelectric heat pump is used to maintain the temperature of an integrated circuit under test. Temperature sensors placed on two sides of the integrated circuit measure and generate signals indicative of the temperature at the two surfaces, and the average of the two measured temperatures is compared against a value of a preset temperature to change the temperature of the heat pump to stabilize the temperature of the integrated circuit to a desired value.

Abstract: A computer system for a zone fired furnace generates a plurality of temperature set point signals for a plurality of furnace zones. The set point signals are derived from a master controller acting on the measured temperature of fluid that is heated in the plurality of furnace zones and then combined to form a heated stream. The master signal, which is a velocity type signal, is provided to a plurality of zone control stations corresponding to the plurality of furnace zones. Each zone control station integrates the master signal, and then biases the master signal for use as a zone temperature set point. The zone control station can be used to bias the individual coils so as to balance the temperature of the coils with respect to each other, or to intentionally unbalance one or more coils, as desired, so as to improve furnace operations.

Abstract: A cooling system for a water-cooled vehicle engine has a radiator through which cooling water flows and which can be exposed to cooling air by an electric fan (9). A first heat sensor (F1) on the engine block senses the water outflow temperature, while a second heat sensor (F2) senses the radiator outflow temperature. The sensed values from both sensors are fed to an electronic control unit (11) which also stores temperature threshold values for both sensor, at which certain functions have to be performed. In the event of failure of either sensor, the electronic control unit (11) takes over the function of the sensor: from the temperature value sensed by the other sensor a temperature equivalent value is formed by adding or subtracting the temperature difference which exists between the two sensors at running temperature. The control unit then activates the appropriate function if the relevant threshold value is reached or exceeded.

Abstract: A system to continually monitor the integrity of control and safety thermocouples within a furnace comprising a low furnace temperature reader connected in parallel with a high furnace temperature reader to a single safety thermocouple.

Abstract: A cooling system for maintaining the temperature within electronic equipment has a circulation system for pumping a cooling liquid, such as water, through the electronic equipment where it picks up heat generated by the electronic equipment. The cooling liquid is pumped through a plurality of heat exchangers using a refrigerant which is, in turn, pumped through a compressor-condensor combination, each heat exchanger having approximately the same cooling capacity. A central control selects the number of heat exchangers which are to operate at any given time, on a basis of the differential in the temperature of the water being pumped into and out of the electronic equipment. This maintains a desired and relatively wide range of temperatures. A heating element selectively and controllably heats the cooled water to bring the wide range of temperatures to a selected and fixed temperature.

Abstract: A method of and apparatus for controlling the heat deformation of machine tools having a plurality of frames is disclosed in which the temperatures at symmetrical or opposite portions of the frames are measured, analyzed and then utilized to maintain the temperatures of the frames at the same temperature, or to maintain a constant temperature difference between the frame portions. The frame portions may either be heated or cooled to obtain the desired temperature.

Abstract: A rapid chill refrigerator has a first chill refrigeration system a second maintenance refrigeration. A product temperature probe and an adjustable timer control the chill refrigeration system to turn it off when a pre-selected product interior temperature is reached or after a predetermined time has elasped.

Abstract: A method and an apparatus for closely regulating the temperature of a laboratory reaction vessel arrangement are proposed which permit a desired temperature change to be rapidly established. In the method, a fluid heat transfer medium is introduced into a thermal chamber formed by a reactor vessel and a jacketing vessel of the laboratory reaction vessel arrangement in a finely turbulent and essentially helically ascending manner. In the apparatus for performing the method, a nozzle is provided in the lower region of the jacketing vessel and extends into the thermal chamber for appropriately introducing the fluid heat transfer medium into the thermal chamber.

Abstract: This invention relates to a tubular element provided with a temperature sensor, in particular for measuring overtemperatures in the tube bundle of superheaters in thermoelectric power plant steam generators, comprising a pair of concentric tubes forcibly locked one into the other by a mechanical plastic deformation process, at least one of the two tubes comprising in the mutually contacting surfaces a series of longitudinal grooves into which temperature sensors are inserted.

Abstract: An automotive air conditioner system including a first detector for detecting a cooling load in the front-seat space of a vehicle passenger compartment, a second detector for detecting a cooling load in the rear-seat space, a discriminator for selecting a larger one of the detected cooling loads, and a controller for controlling operation of a refrigerant compressor in accordance with the selected cooling load.

Abstract: A two-stage thermostat means for an add-on heat pump installation provides separated control of a furnace and a heat pump. The two-stage thermostat means utilizes a single pole, single throw switch means, and a single pole, double throw switch means to properly stage and control a heat pump and a fossil fueled furnace so that they do not overlap. The control of the temperature of the heated area is independent of any need to connect a circuit between the thermostat in the heated area and any type of thermostat at the heat pump itself.

Abstract: A dual probe interactive, control system for accurately controlling the temperature within a specified area has a controlling temperature probe located for fast response times and used in association with a controllable setpoint for modulating a heating/cooling source. An indicating/reference temperature probe is also placed in the same enclosure at an optimum location for indicating actual temperature. The actual temperature is compared to the desired temperature to detect any droop or offset and the controllable setpoint is then adjusted accordingly.

Abstract: A thermostat monitoring and controlling the temperature of produce ripening within an enclosure and featuring a bridge circuit sensing errors between the actual and desired temperatures in which the desired temperature is selected directly in units of degrees. A bridge amplifier having feedback maintains the bridge in electrical balance to avoid errors due to changes in bridge component self heating. An error detection circuit having a single control simultaneously selects upper and lower error limits centered on the desired temperature, in units of degrees. The circuit indicates whenever the actual temperature goes outside these limits. An alarm circuit indicates a temperature error or a power failure in the thermostat at the thermostat and at a remote location. This circuit utilizes an alternating current source which activates current direction-dependent indicators operating on alternate half cycles.

Abstract: Three or more temperature sensors are positioned at various selected locations in a building. These sensors are connected to an averaging circuit whose function is to provide an electrical signal which is functionally related to the average temperature of all these sensors. This electrical signal is compared with another signal which is related to a pre-determined reference temperature for the building. If the electrical signal related to the reference temperature is greater than the electrical signal related to the average temperature indicated by the sensors, a comparator circuit turns a boiler on to heat the building. When the reverse situation is true, the comparator circuit operates to turn the boiler off.

Abstract: A plastic extruder system having a barrel and a shell with heat exchange elements surrounding the barrel is disclosed. Two thermocouples are provided, one for sensing the temperature of the inner surface of the barrel and the other for sensing the temperature of the shell. A system controller, into which a desired barrel setpoint temperature can be set and stored, receives and stores the independent temperature signals from the thermocouples and controls the heat exchange elements to automatically maintain the temperature of the extruder barrel close to the desired barrel setpoint temperature.