Abstract: Air trim control actuator mechanically connects a fuel flow device to an air flow device for setting the air to fuel ratio in combustion apparatus. An air to fuel ratio control unit is responsive to electrical input signals from an oxygen sensor that monitors the combustion products in the stack emissions. The air trim actuator includes a pivotally mounted input arm that is mechanically connected to the control unit and is pivoted to a preselected position corresponding to the selected boiler load. The input arm is connected by a link to an output arm which is pivoted through a preselected range of movement to control the position of the damper. The output arm has an elongated arcuate slot for receiving the end of the link. The output arm is pivoted to a position corresponding to the pivoted position of the input arm for selectively positioning the damper to provide air flow to the boiler for the desired air/fuel ratio.

Abstract: A combustion control device which performs combustion control based on the ambient oxygen content by using an electrode rod to be put into a flame. The combustion control device comprises an a.c. power source, a circuit connected to the a.c. power source to produce a reference voltage corresponding to a change of supply voltage, a circuit connected to the a.c. power source to detect a flame current depending on the ambient oxygen content and the supply voltage, the detecting circuit producing a detection voltage corresponding to the flame current, a circuit for comparing the detection voltage and reference voltage, and a circuit receiving an output signal from the comparing circuit to control a fuel supply valve.

Abstract: A liquid waste feeding system to be used in conjunction with a solid waste, pyrolytic incinerator. The liquid waste is atomized and injected into the upper end portion of the pyrolysis chamber of the incinerator through a retractable nozzle assembly. The nozzle assembly is automatically extended into the pyrolysis chamber during periods when the liquid waste is to be supplied to the incinerator, and is retracted to a location outside of the chamber when liquid waste is not being supplied. The feed rate of the liquid is controlled by the incinerator stack temperature and modulates between two temperature set points. At the upper set point, the feed rate decreases on temperature rise, which will occur when burning liquids with high BTU values. At the lower set point the feed rate decreases on temperature drop, to insure that minimum combustion temperatures are maintained in order to achieve complete burnout in the incinerator thermal reactor.

Abstract: A burner of wick type is disclosed which secures user safety by stopping combustion through an oxygen depletion protection function in the event of an oxygen depletion. When tar is accumulated in the wick, the wick is burnt to clean the tar with the liquid fuel supply cut off, thus burning out the liquid fuel contained in the wick. In the process, the combustion temporarily becomes unstable and a great amount of carbon monoxide is generated, resulting in a state similar to oxygen depletion. In a burner with an oxygen depletion protection function, the combustion is stopped during the wick cleaning, with the result that most of the tar accumulated in the wick remains unburnt, adversely affecting both the fuel absorption characteristic and service life of the wick. This invention is such that the oxygen depletion protection function is not operated during the wick cleaning.

Abstract: A gas combustion apparatus is disclosed wherein an oxygen sensor having electrodes on both surfaces of a base body is fixed in advance at a position such that the oxygen sensor is within the exhaust gas a combustion flame under normal conditions and a combustion flame under oxygen deficiency conditions is brought into contact with only the measuring side electrode. The oxygen sensor is preferably mounted to a heat-resistance holder having an opening such that the measuring side electrode corresponds with the opening.

Abstract: Methods and apparatus for regulating furnace combustion air flow are provided which measure a gaseous combustion product in furnace gas after combustion, generate a present signal responsive to the measurement and change flow rate of combustion air in response to the generated signal in a manner the same as flow rate was changed in response to a previously generated signal if the present signal relates to the previous signal in the manner the previous signal related to a signal ancestor thereto but change the flow rate of combustion air in response to the generated signal in a manner opposite the manner the flow rate was changed in response to the previously generated signal if the present signal relates to the previous signal in a manner opposite the manner the previous signal related to a signal immediately ancestor thereto.

Abstract: A combustion control process and apparatus provides a reference flame of known or constant composition which is in ionic communication with the main flame which is to be controlled. Both the reference and main flames are supported by electrically insulated burner nozzles and the flames are in mutual electrical communication through ionized gases. The potential difference is measured between the flames by way of the nozzles and is used in the air-fuel ratio adjustment of the main burner. Additionally, the main burner can function as a reference point in combination with a zirconia oxygen sensor to ascertain potential differences therebetween, which differences reflect the air-fuel mixture of the main flame.

Abstract: A draft control system for furnaces comprises an auxiliary channel in communication both with ambient air and the flue of the furnace, a main draft control means for regulating the entrance of ambient, auxiliary draft air into the flue, and auxiliary draft control means mounted in the auxiliary channel for dampening the effect of extreme changes in external conditions on the main draft control means. Thus, uniform draft and efficient combustion is maintained in the furnace under a wide variety of conditions. The main draft control means comprises counter-balanced draft control plates which are initially set in an open position so that they can either open or close in order to efficiently regulate the draft in the flue. The auxiliary draft control means comprises, in one embodiment, an isolation damper plate rotationally mounted in the auxiliary channel, or, in a second embodiment, a set of louvred panels.

Abstract: A combustion sensing apparatus having a solid electrolyte disposed in the vicinity of a burner and having a tabular form. Thanks to the tabular form of the solid electrolyte, the production of the apparatus is very much facilitated and the areas occupied by the anode and cathode are minimized. The construction of the apparatus as a whole is simplified and the reliability of the same is improved remarkably. In addition, the cost of production is lowered advantageously.

Abstract: A combustion device includes a fuel-air ratio controller. A control is coupled to receive a first signal functionally related to the status of the fuel-air controller and a second signal from an oxygen sensor which is functionally related to the oxygen in the discharge gases from the combustion zone. The control is operative to provide an output signal to a fuel regulator for adjusting the fuel delivered to the combustion zone in relation to the oxygen in the discharge gases.

Abstract: A device for detecting the presence or absence of flame in a combustor and an oxygen density of room air used to operate the combustor. An ion current detecting sensor increases a flame ion current value in the combustor to an ion current value at which erroneous detection of the presence or absence of flame is prevented. A timer outputs a high level signal when combustion starts and starts a timer operation for holding the high level signal until the ion current is stabilized. Thereafter, the time outputs a low level signal which grounds a circuit to lower the flame presence or absence detecting ion current value detected by the sensor.

Abstract: In a control system for a gas heated water or air heater, the use of the supplied fuel gas is to be improved by automatically determining and supplying the amount of air which is required for obtaining complete combustion. A gas control valve feeds a burner with the required amount of gas dependent on the demand of heat. A sensor responding to the content of oxygen or carbon dioxide within the flue gases is located in the stack and the output signal of this sensor is compared with a set point within an electric controller. In case of a control deviation, the output signal of the controller controls an adjustable source of air under pressure formed by a fan with subsequent air control valve in such a manner that the required amount of air for reaching optimum combustion is supplied.

Abstract: A system for marginally adjusting the fuel flow to a burner to maintain the proper oxygen content in the exhaust from the burner is disclosed. The burner is of the type where both the fuel and air flow rates are adjusted in a substantially fixed ratio in response to load changes on the system with the fuel being adjusted by a fuel control valve mounted in a fuel supply line. A self-operating pressure regulating valve having an actuator responsive to the differential pressure across the fuel control valve is mounted in the fuel line upstream of the fuel control valve. A set point adjustment mechanism is mounted on the regulating valve actuator to adjust the set point of the regulating valve in response to an oxygen controller which senses the oxygen content in the stack gases. The set point adjustment mechanism has a cam assembly which continously adjusts the set point of the regulator actuator by varying the compression on a spring loaded diaphragm therein.

Abstract: An oxygen density detecting device for a combustor in which individual adjustment of reference levels for each combustor is not necessary. A memory device stores a reference ion current value from a sensor disposed in the combustor for a predetermined period of time extending from the time instant at which combustion breaks out in the combustor until the ion current has substantially stabilized. The oxygen density of the room air used by the combustor is determined by comparing the ion current value stored in the memory with ion current values which are successively provided by the sensing device. An output signal produced thereby is utilized to control circuit elements including a fuel supplying electromagnetic pump and a combustion air blower used for supplying room air into the combustor.

Abstract: The efficiency of a furnace is substantially maximized by manipulating the amount of oxygen supplied to the combustion process in the furnace so as to provide a desired oxygen concentration in the flue gas which will result in substantially maximum furnace efficiency. Feed forward control based on the fuel flow rate may also be utilized to enable the control based on oxygen concentration in the flue gas to respond more quickly to a change in the fuel flow rate.

Abstract: A safety apparatus for shutting down a room heating device upon detecting incomplete combustion in the burner of the heating device. A detecting element is arranged to provide an output to a setting circuit. When the output changes due to a change in combustion, the circuit cuts off fuel supply. Additional circuitry is provided to vary the predetermined operation level of the circuit depending on whether a room air circulation fan is operating or not.

Abstract: The invention relates to a method for operating a gasification (or vaporizing) burner/heating boiler installation and has the objective to develop such an installation in such a manner that it can be operated controllably. According to the invention, the required burner output is determined for this purpose from the outside air temperature, and then the mass flows of the heating oil and the air are controlled as a function of the demanded burner output, deviations from the stoichiometric ratio between the heating oil and the air being leveled-out by means of a lambda-probe arranged in the exhaust gas stream.

Abstract: A combustion detecting element is provided which comprises an element body generating an electric change which corresponds to a difference in oxygen concentration between a first surface and a second surface thereof. Catalytic electrode layers are provided on both surfaces for carrying out catalytic reaction with combustible gas and a lead wire is connected to each layer, the catalytic electrode layers being characterized in that each catalytic electrode layer has substantially different capabilities in catalytic reaction with combustible gas.

Abstract: There is provided a combustion safety apparatus where the main burner has a combustion detecting element such as an oxygen concentration cell element, and the element is arranged so that one electrode thereof is always heated by a flame of a standing burner and into an oxygen lack condition while the other electrode is heated by the main burner. When the main burner is in its complete combustion condition, there is a difference in oxygen concentration between the two electrodes and thereby there is generated an output at the element. On the other hand, when the main burner is in its incomplete combustion condition, the difference in oxygen concentration therebetween is decreased and thereby the output is lowered. In addition there is provided a safety device such as a gas safety valve or the like.

Abstract: A furnace air volume control apparatus for controlling the volume of furnace air to achieve efficient burning is disclosed. The apparatus includes regulating valves positioned within supply air inlets and exhaust gas outlets of the furnace. A measured data receiver positioned on the exhaust gas side transmits a measuring signal to a control unit connected to the regulating valves. The control unit includes a storage unit for storing valve positions assigned to respective burner loads. By monitoring various exhaust gas parameters with the measured data receiver and control unit valve position, adjustment in response to changes in the burner load is possible by comparing a previously stored valve position recalled from the storage unit with a characteristic curve. The valve adjusting value stored in the storage unit is essentially congruent with the change in burner load. After exhaust gas stabilization has occurred in response to different burner loads precise correction of the valve position value occurs.

Abstract: A combustion safety arrangement in which a switch is connected in an electrical power circuit for an electromagnetic valve in a fuel passage. A combustion detecting element responds to a change of a flame caused by incomplete combustion or the like, and generates a signal or change in an electrical characteristic. The switch and the combustion detecting element are interconnected through a control circuit which has a level detector for detecting a predetermined level of the change in electrical characteristics. The arrangement is such that the switch may be opened by the predetermined level of the change in electrical characteristics. The control circuit has a time limit operation circuit so that only when the generation of the change in electrical characteristic is continued for a delayed time set by that time limit operation circuit, the switch may be opened.

Abstract: A combustion safety apparatus wherein combustion exhaust gas of a burner is arranged to be introduced into a detecting tube having a tubular oxygen concentration cell element, and a safety valve is arranged to be controlled in operation by the output of the cell element. The detecting tube is in communication at its outlet opening with a mixing tube of the foregoing burner or another burner.

Abstract: In a combustion appliance with a safety device therein, an inner flame cylinder, a red-heat cylinder and an outer cylinder disposed concentrically on the outer side of the red-heat cylinder are provided to constitute a combustor and an oxygen sensor is disposed in the rear flow of the combustion flames of the combustor and in a position where the air excess ratio of the flames can be detected. During the incomplete combustion through air feed shortage or the like caused due to dust clogging or the like as well as during the oxygen depression, the oxygen sensor can detect changes in the flames or changes in the red-heat condition of the red-heat cylinder to stop the burning operation thereby to secure the safety.

Abstract: A method of automatic combustion control in a combustion system comprising a combustion chamber, combustion means for causing the combustion of fuel in the chamber, a heat exchanger connecting with the combustion chamber, an exhaust passage connected with the heat exchanger, and fuel supply means for supplying fuel to the combustion means, such method comprising measuring the combustion temperature in the combustion chamber and producing a first quantity corresponding in magnitude with the combustion temperature, measuring the exhaust temperature in the exhaust passage and producing a second quantity corresponding in magnitude with the exhaust temperature, producing a summation of the first and second quantities and thereby producing a summation quantity, and varying the supply of air to the combustion means in such manner as to maximize the summation quantity, whereby the combustion efficiency is also maximized.

Abstract: A combustion control system for a furnace monitors the oxygen content, carbon monoxide content and temperature in the flue gas exhausting from the combustion chamber. These parameters are used to calculate total heat loss due to unreacted oxygen and the other excessive air components associated therewith, and carbon monoxide. Such heat loss calculations are continuously made and compared to determine whether total heat loss, oxygen related heat loss and carbon monoxide heat loss are increasing or decreasing. Depending upon the combination of increase and decrease associated with the various heat losses, the combustion air supply is increased or decreased. In this manner it is possible to minimize heat loss and maximize furnace efficiency even though the combustion characteristics of the combustion unit may change with time.

Abstract: A method and system for controlling the combustion of, for example, coal or bark in a stoker boiler or black, liquor in a recovery boiler to provide operation at maximum efficiency. Control loops are provided for primary or undergrate air and secondary or overfire air. The undergrate air control loop is adjusted as a function of carbon dioxide or steam/fuel ratio, and the overfire air control loop is adjusted as a function of carbon monoxide. In addition to carbon monoxide, combustibles and opacity may be used. Air redistribution is also used to minimize combustibles or CO or opacity.

Abstract: In a recovery boiler having a plurality of air inputs, with the primary air input closest to the bed of the boiler, a fuel input, a smelt output, and an exhaust output, a method of controlling the combustion of fuel in the boiler to operate at the maximum reduction efficiency. The method includes the steps of measuring the amount of sulphur dioxide at the exhaust output; and varying the amount of air entering into the boiler through the primary air input until the minimum amount of sulphur dioxide is measured at the exhaust output.

Abstract: A combustion control system which utilizes non-linear parameters for controlling a combustion process with greater efficiency than has heretofore been available is disclosed. According to the method, the quantity of carbon monoxide, unburned hydrocarbons, and/or opacity is measured and compared with a predetermined value for that parameter. Error signals for each parameter are generated and supplied to an error selector which chooses the error signal of the largest magnitude. The error signal is then compensated for the non-linear relationship between the parameter and the amount of excess air supplied to the combustion process. Other operations, including checking the proposed control signal output against one or more constraints are performed, and if satisfactory, an output signal is supplied to a servo-mechanism for controlling the air flow to the combustion process.

Abstract: There is provided a combustion appliance with a safety device. An oxygen partial pressure sensor made up of a transition metal oxide or rare earth metal oxide is normally disposed in a position in which the excess air ratio downstream of a flame formed by a burner can be detected and, at times of abnormality, within the flame. The resistance change of said oxygen partial pressure is detected and the combustion is stopped when incomplete combustion occurs due to oxygen depression, clogging of the primary air orifice of the burner or clogging of the combustion chamber with the products of combustion.

Abstract: A microprocessor based controller for regulating the position of a stack damper in a combustion furnace by feedback control adjusting damper position in view of an operator input target value of excess oxygen and an actual monitored excess oxygen value. A feedforward control overrides the feedback control for a time period initiated by the feedforward control responding to process variables indicating increase in combustion demand.

Abstract: An apparatus and method for controlling combustion in a furnace is described. The flue gas content is monitored to determine the oxygen and/or carbon dioxide components therein to provide a control signal which is compared with a control signal from a fuel flow sensor to provide an infinitely variable speed control for a blower which supplies combustion air to the furnace being controlled. The speed of the blower is varied in accordance with the flue gas content and the fuel flow rate to provide a continuously variable blower speed to at all times effect optimum combustion efficiency.

Abstract: The fuel supply to a boiler (11) is controlled by a fuel valve (17) driven by a motor (18) in response to measured steam pressure at (12) in relation to a demanded pressure. The motor (18) adjusts at the same time a damper (36) for supplying combustion air at (13). Air supply at (13) can also be controlled in response to the pressure drop across a register (38) as measured by airlines (51). The invention provides an over-riding control in response to too much or too little oxygen in the exhaust gases in the stack (15). The oxygen level is measured by a detector (26), and if it is outside limits set at (29) a motor (41) operates a valve (42) connected between the airlines (51). A timer with a contact T1 ensures that the control in response to oxygen level is only operative for a small part of each of a number of repeated 10 second cycles.

Abstract: A method of controlling the opacity of the exhaust of the combustion of solid fuel and air in a furnace comprises measuring the opacity of the exhaust. The amount of air and the direction (i.e., increase or decrease) entering into the furnace is changed. The opacity of the exhaust is measured again. The later measured value of opacity is compared to the earlier measured value. The amount of air entering into the furnace is controlled based upon the comparison.

Abstract: An automatic vent damper and fuel valve control for a fluid fuel-fired furnace including an electrically-operated valve in the fuel line, a normally-open damper in the furnace vent having electrically-operated means for closing the damper, and a thermostat for sensing the temperature in the space being heated. A Hall-effect generator is employed for sensing the positions of the damper and for respectively providing signals in response thereto. A gas detector is provided for sensing the presence of hydrocarbon-containing gas in the region of the draft hood and vent of the furnace and for providing a gas-present signal in response thereto. A control is provided for the valve responsive to both the damper-open signal and the thermostat calling for heat to energize the valve to open the same, the valve control de-energizing the valve to close the same in response to the thermostat calling for termination of heating, or the damper-closed signal, or the gas-present signal.

Abstract: A system for monitoring the operation of a heating apparatus having a combustion chamber with associated air and fuel supplies and an exhaust path includes sensors for monitoring temperatures at the combustion chamber. A microprocessor and a display receives signals from these sensors and has a keypad to permit calculation and display of parameters indicative of proper operation of the heating system including fuel usage per unit time. Limit values can be stored in the processor memory to trigger alarms when temperatures or fuel usage exceed the set limits. Various measured and calculated values can be displayed.

Abstract: In a process and apparatus for the continuous burning of a fuel, the fuel is run into a combustion space where it is burnt after being ignited, making use of oxygen-containing gas run into the space. The relation of gas to fuel is changed dependent on the adjustment, of a desired oxygen content in the flue gas current. For making certain of an unchanging combustion power, the fuel inlet rate is controlled to be directly dependent on the adjustment of the oxygen content in the flue gas while keeping up an unchanging rate of input of oxygen-containing gas into the combustion space.

Abstract: A method and apparatus for the heat treatment of industrial wastes wherein at least some of the constituent materials of the wastes are subjected to combustion and/or to pyrolysis to produce flue gases and, in some applications, a residue. The supply of an oxygenated combustion-supporting gas to the wastes is regulated as a function of at least one sensed predetermined characteristic of the flue gases. The oxygenated gas may be a mixture of air and substantially pure oxygen, the feed rate of one or both of these being regulated in response to the sensed temperature and/or oxygen content of the flue gases. Such regulation maintains the oxygen content of the flue gases within the range of from 0 to 7%; and the temperature of the flue gases may be maintained from 400.degree. to 1200.degree. C. and, preferably within a range of 50.degree. C. in this region.

Abstract: Apparatus and method for changing the calibrated linkage relationship between two flow control devices of combustion apparatus without impeding the normal operation of the associated process. Means are provided, responsive to remote, manual or automatic control, to calibrate a jackshaft linkage type of control apparatus in order to provide for range changes and zero adjustment.

Abstract: This invention relates to a furnace equipped with a fuel optimizer for more effectively controlling fuel consumption in the furnace and a method for using the furnace fuel optimizer. In particular, the invention relates to a furnace fuel optimizer which controls combustion air by maximizing radiant section heat transfer with respect to convective section heat transfer while monitoring CO emissions in the flue gas and monitoring the draft below the convective section in order to obtain an optimum control value. The furnace fuel optimizer then regulates the furnace to correspond to the optimum control value by adjusting the air input to the furnace so that continuous furnace operation is possible at maximum efficiency.

Abstract: This invention is a control for a burner enabling it to operate efficiently with very little excess air but providing a main control for the fuel and for the combustion air in response to demand, and an auxiliary control in response to the amount of free oxygen in the products of combustion. The latter quantity can be measured by a zirconia cell, and there are means for controlling its temperature accurately so that the reading is reliable. The controls in response to demand and excess air respectively are applied alternately in a cycle with a period of no control to enable the effect of an adjustment to be established before further control is applied.

Abstract: A circuit means in combination with a conventional oxygen ion conductive solid electrolyte cell establishes the cell in a voltage mode for the purposes of measuring excess oxygen and developing a voltage signal indicative thereof, and switching the cell to a current mode of operation in response to an excess combustible environment wherein current drawn by the cell to pump oxygen for combustible reaction with the excess combustibles environment is measured as an indication of the combustibles content of the gas.

Abstract: A system of preheating of gaseous fuels to a furnace in which the fuels have a wide range of molecular weights, and corresponding calorific values, and in which all of the combustion air is provided by inspiration, due to the flow energy of the fuel. The invention involves the monitoring of oxygen in the products of combustion moving from the furnace to the stack, or, alternatively, monitoring the molecular weight of the fuel on the inlet line, and controlling the preheating of the fuel in a heat exchanger, so as to maintain a selected temperature of the fuel going to the burners, in accordance with the molecular weight of the fuel.

Abstract: A combined smoke detection and furnace shut-off device is provided having a smoke detection means which is disposable adjacent a furnace for detecting the presence of smoke unnaturally emitted from the furnace, a means for stopping ignition within the furnace, and means responsive to detection of the smoke by said smoke detection means for activating the ignition stopping means.

Abstract: A feed forward system coupled with a feed back system is used to control the efficiency of combustion of fuel in a furnace. The feed forward system has sensors to measure the fuel flow rate and the quality of the fuel. The measurement of the sensors is used to calculate the theoretical oxygen flow rate needed to combust the fuel. The theoretical oxygen flow rate and an excess oxygen level are used to determine the actual air flow rate, which is used to control the air input to the furnace. The feedback system has a sensor to detect combustibles near the exhaust of the furnace. The measurement of the combustible sensor is used to control the excess oxygen level. In a preferred embodiment, another sensor, an oxygen sensor, is placed near the exhaust of the furnace. The oxygen sensor provides a dynamic check on the actual amount of excess oxygen level within the furnace. Finally, the oxygen sensor is also used as a safety device in providing redundancy to the combustible sensor.

Abstract: A differential controller for a jackshaft or a positioning combustion system having an input shaft coupled to a fuel valve and an output shaft coupled to an air damper. The controller includes means for sensing a transmitted signal indicative of the level of oxygen in the products of combustion and in response thereto differentially adjusts the vernier position of the output shaft relative to the input shaft to provide optimum fuel use under all operating conditions. The controller includes means for precluding differential travel between the shafts at low fire (load) positions. As load demand increases the controller enables differential travel to occur with increasing demand, with the amount of differential travel permitted being a function of increasing load. The maximum range of differential travel is adjustably predetermined.

Abstract: A system for the continuous analysis of furnace gasses for carbon dioxide and oxygen levels is disclosed. Materials which would be detrimental to the measuring instruments are removed before the gasses reach the measuring instruments. In particular, moisture content is removed by condensation at temperatures near freezing whereafter the gas is permitted to continuously warm up as it goes through the measuring instruments so that no condensation takes place in the measuring instruments.

Abstract: An improved combustion detection apparatus is disclosed that can be employed in a fail-safe control circuit for a combustion apparatus to operate a shut-off valve in the fuel supply in response to the presence or absence of combustion. The improved combustion detector is an electrode assembly of a solid metal oxide member and electrodes in the form of electrical conducting coatings on opposite sides of the metal oxide member. The metal oxide has the characteristic of generating an electromotive force by transfer of oxygen ions therethrough. The combustion detector is placed in the vicinity of a flame from a pilot or main burner of the combustion apparatus. The oxygen gradient established by the burner flame and the resultant high temperature of the metal oxide member provides an instantaneous response to ignition or extinguishment of the burner flame.

Abstract: Combustion of fuels each containing at least one combustible component, wherein, while the composition of each combustible component is known, the mixture ratio of only one combustible component is yet unknown, is automatically controlled by: measuring the flow rate of each fuel, the flow rate of air for the combustion, and the percentage proportion of residual oxygen in the combustion exhaust gas; introducing the values thus measured as input into a combustible component ratio detector comprising an operational circuit according to a combustion reaction formula thereby to automatically determine the unknown combustible mixture ratio; multiplying this mixture ratio by a flow rate signal corresponding to the same fuel; and utilizing the resulting product value for automatic control of the flow rate of each fuel and the combustion air.

Abstract: A method for producing a dense and impervious stabilized hafnium oxide ceramic having zero percent water absorption is disclosed. The hafnium oxide is stabilized in the sense that a solid solution with Y.sub.2 O.sub.3 is formed. The solid solution has a cubic crystal structure which, because of its similarity to the structure of the mineral fluorite, is sometimes called a "fluorite phase"; unlike hafnium oxide alone, which undergoes a destructive phase transformation from tetragonal to monoclinic during cooling, the cubic structure of the solid solution remains stable during cooling of a ceramic article.

Abstract: A safety equipment for a gas burner is disclosed wherein a combustion sensor comprising an oxygen concentration cell having porous electrodes disposed on both sides of a sintered body of ion conductive solid electrolyte, is provided, so that incomplete combustion and extinction of the burner are detected by a change in e.m.f. of the sensor and a change in resistance of the sensor. The detected signal is used to block the feed of fuel to the burner in order to prevent CO gas poisoning and explosion.