Abstract: A high reliability heating system that includes dual furnace control mechanisms wherein each furnace control mechanism includes blowers and control elements and each is independently operable to control the operation of a shared furnace burner unit and heat exchanger. The heating system preferably includes a controller mechanism selector mechanism that detects an abnormal operating condition, malfunction, in the controlling furnace controller mechanism and, in response, automatically switches control to the other furnace controller mechanism.

Abstract: An electronic thermostat having high and low voltage control capability and varied functional capabilities. The thermostat is particularly suited for use with fan coil heating and cooling units. Specifically the thermostat uses relays to actuate external devices such as heating and cooling equipment, fans and dampers. The use of relays permits control voltages for these external devices to be different (e.g. 24 VAC, 208-230 VAC or 277 VAC).

Abstract: A temperature control device with high accuracy and stability comprising a heating device and a cooling device which are controlled by separate control circuits for performing proportional control, integral control, derivative control and the like. A ratio of energy supply periods to predetermined control periods is thereby varied, on the basis of a controlled variable calculated from direction, size, change velocity and the like of deviation of actual temperature of a controlled medium from desired set temperature so as to control heating and cooling energy supplies for the heating and cooling devices. The heating energy and cooling energy supplies for the heating and cooling devices can be separately controlled by means of different proportional bands.

Abstract: A two terminal line voltage thermostat includes a switch which connects one side of the line voltage to a heater load (that it drives) such as a baseboard heater with the other side of the heater being connected to the other side of the line. Common full wave rectifier components drives both a relay coil and the remaining electronics of the thermostat. In addition, an arc suppressing triac across the switch while necessarily connected to the primary side of a transformer is directly driven from the secondary which is ungrounded; the primary also provides choking for the triac.

Abstract: There is disclosed a thermostat controlled apparatus which controls the operation of a heating system and a cooling system in response to temperature variations in a given environment. The thermostat has a three-electrode mercury switch which is coupled to a single bimetallic element which rotates the switch in response to temperature variations. The switch has a housing containing a pool of mercury and three electrodes extending within. A common electrode is connected to a voltage source. A second electrode is connected to the cooling system. A third electrode is connected to the heating system. Tilting the switch clockwise causes the mercury to connect the second and common electrodes, thereby energizing the cooling system; tilting the switch counterclockwise causes the mercury to connect the third electrode and common electrode, thereby energizing the heating system.

Abstract: There is disclosed a thermostat controlled apparatus which operates to control operation of a heating system and a cooling system in response to the temperature detected in a given environment. The thermostat has a pair of mercury switches which are coupled to a single bimetallic element which switches are inclined, one with respect to the other. The circuit configuration is such that one switch controls the heating operation while the other switch controls a cooling operation. Heating and cooling occurs within a predetermined range which is adjustable by means of the angular positions of the switches with respect to the bimetallic coil. In this manner one switch will control the heating operation and the other switch controls the cooling operation. There is an area between the setting of the thermostat wherein neither switch operates but during this mode a separate fan is energized to provide air circulation for the given environment.

Abstract: A temperature control device is disclosed for use in a vending machine having a plurality of storage chambers. The temperature control device includes a refrigerating apparatus provided with a plurality of evaporators which are connected in parallel and disposed individually in the storage chambers. A plurality of electromagnetic valves are coupled in series with the evaporators to control the inflow of refrigerant fluid. The operation of each electromagnetic valve, i.e., the temperature control in each storage chamber is controlled by a comparison of the average temperature of the storage chambers with the actual temperature in each chamber. The operation of the refrigerating apparatus and the electromagnetic valves are also controlled by a comparison between the desired temperature and the actual temperature in each chamber.

Abstract: A differential scanning calorimeter includes a baseline correction apparatus which simultaneously corrects for both linear and curvilinear heat flow variation between the sample and reference holders.

Abstract: Disclosed is a method of controlling an enamelling oven, in which a plurality of controlled variables such as temperatures:Y=(Y1 . . . Yl)including a plurality of measured variables:(Y1 . . . Ym)are variable by any one of a plurality of manipulation variables such as the degrees of opening of dampers:U=(U1 . . . Um)where l and m are positive integers equal to or greater than 2 with m>l. The method comprises the step of controlling the controlled variables to reach reference values therefor:YR=(YR1 . . . YRl)by effecting integrating action on each of variable factors:U'c=(Uc1 . . . UcM)which are derived from the differences between the controlled variables and the reference values:Y-YR=(Y1-YR1 . . . Y-YRl)=(.epsilon.1 . . . .epsilon.l)to produce outputsUc=(Uc . . . UcM)which serve as the controlled variables, respectively.

Abstract: In a process in which a furnace having multiple coils is utilized to heat a fluid stream, a comparison of a measured pressure of the fluid stream to a desired pressure is utilized to bias a temperature control system for the furnace which maintains the furnace outlet temperatures from the plurality of coils substantially equal so as to substantially maximize the transfer of heat to the fluid stream while maintaining a desired pressure for the fluid stream. If multiple furnaces are utilized, a bias term based on a comparison of the total flow through each furnace may be utilized to bias the temperature control system so as to maintain a desired split in the total flow between the plurality of furnaces.

Abstract: A gas mixer and reactor is provided which includes an elongated gas flow chamber with a nozzle arrangement at its inlet end for passing a first gaseous reactant into the interior of the chamber, toward the outlet of the chamber from points uniformly about the inner periphery of the chamber, and an annular nozzle arrangement near the outlet of the gas flow chamber for directing another gaseous reactant, or reactants, through the outlet of the gas flow chamber and into a thermal reaction chamber which communicates with the outlet of the gas flow chamber. In this manner controlled amounts of gaseous reactants may be thoroughly admixed and reacted to produce an atmosphere of desired composition. Atmospheres for kilns having controlled amounts of free hydrogen, carbon monoxide, oxygen, or carbon for example, are produced by burning controlled ratios of fuel, air and in some cases an inert gas, mixed by the reactor.

Abstract: A method of and system for controlling the temperature of a continuous furnace through which steel bodies are transported at a constant speed, in which the temperature is controlled so as to keep the distance from the entry port of the furnace to a position in the furnace where the furnace temperature is substantially equal to the desired delivery temperature of a steel body to be heated at a predetermined value which is determined in accordance with the dwell time, shape and size of the steel body.

Abstract: The invention involves a closed loop control method and apparatus for starting up a steam-heated heat exchanger by controlling the heating-steam pressure. According to the invention a correcting variable is established by a controller from an actual pressure value, measured by an actual value transmitter, and from a reference value, generated by a reference value generating device, the heating-steam pressure being modified by at least one control valve on the basis of said correcting variable. The pressure reference value S is selected from three pressure set values, S.sub.T, S.sub.P1 and S.sub.P2, the lesser value of S.sub.T and S.sub.P1 being established as an intermediate pressure set value S' (that is, S' = Min (S.sub.T, S.sub.P1)), and the pressure reference value S is selected as being the greater value of S' and S.sub.P2 (that is, S = Max (S', S.sub.P2)), where S.sub.T represents that permissible maximum desired pressure value which is a function of the momentary metal temperature T.sub.

Abstract: A control system for energizing and de-energizing an external load in series with a source of electricity incorporates a rectifying network having inputs in series with the alternating current source and the external load. An electronic switch of the system activates the load by effectively shorting together the inputs to the control system when the combination of externally sensed parameters obtain predetermined magnitudes. The sensed parameters control the activation of the electronic switch by a plurality of control modules which interact with a control logic module, representing a Boolean combination of the control module outputs, so as to activate a trigger module which in turn causes the electronic switch, such as a silicon controlled rectifier (SCR) to be triggered. The external load is then energized by the SCR effectively shorting the inputs to the control system and which thus completes the electrical path from the source of electricity through the load.