Abstract: Nitrous oxide emissions are reduced in an industrial thermal process and system which operates a gas fired burner at substantially sub-stoichiometric conditions to produce products of combustion rich in combustibles and control flame temperatures at temperatures which do not exceed predetermined levels. Completion air at stoichiometric proportions is subsequently employed to burn the combustibles. Regenerative and recuperative means to cool gases after each partial combustion step are used to extract heat and use is in conventional heating processes. A novel regenerative heat exchange system is used to extract heat from the gases so that the gases never exceed a temperature whereat nitrous oxide formation tends to occur.

Abstract: Apparatus for rapidly and precisely removing and replacing surface mount devices without disturbance to nearby devices on a printed circuitboard, the invention utilizes a multiple nozzle arrangement wherein nozzles arranged for reciprocating motion one each along each edge of a surface mount device direct low velocity hot gas against bond joint locations along the respective edges of the surface mount device, thereby to melt the bonding agent mounting the device to the circuitboard. The multiple nozzle arrangement of the present system thus allows removal and/or replacement of devices of widely varying dimensions without the need for changes in nozzle size such as is inherent in prior art hot gas rework stations.

Abstract: A gas-injection lance, burner, and method for use in a high temperature heating system which provides a non-axisymmetric flow of a reaction-rate enhancing gas in sufficient proximity to the flame of the system, which extends over the surface to be heated, to create an aerodynamically reduced pressure field sufficient to deform the flame and displace it in the direction of the surface to be heated. The present method provides substantially enhanced heating with the virtual elimination of hot spots.

Abstract: A gas-injection lance, burner, and method for use in a high temperature heating system which provides a nonaxisymmetric flow of a reaction-rate enhancing gas in sufficient proximity to the flame of the system, which extends over the surface to be heated, to create an aerodynamically rreduced pressure field sufficient to deform the flame and displace it in the direction of the surface to be heated. The present method provides substantially enhanced heating with the virtual elimination of hot spots.

Abstract: A drum mixer asphalt plant is provided with a rotatable cylinder 10 in which virgin aggregate, recycle material and liquid asphalt are mixed to produce an asphaltic composition and the hot gas stream for heating and drying the materials flow in countercurrent relation. In a first zone within the cylinder 10, aggregates are heated and dried by heat radiation and a hot gas stream generated at a burner head 46 of a combustion assembly 40. In a second zone within the drum cylinder 10 isolated from the burner flame and hot gas stream by the combustion assembly 40, liquid asphalt is sprayed from an injection tube 76 to mix with aggregate materials. A recycle feed assembly 60 delivers recycle asphalt material to the second zone also for mixing with the aggregate and liquid asphalt.

Abstract: A system including a method and apparatus for treating waste containing organic contaminants which includes a direct fired, countercurrent, rotary kiln providing a soaking zone having an oxidizing atmosphere through which the materials being treated are passed after the unwanted organics are removed, and a secondary combustion chamber for oxidizing gases containing vaporized or pyrolyzed organics in which the organics are burned and are subjected to high temperatures for a holding time sufficient to effect destruction of the organic contaminants. The system includes means to minimize off-gas so as to make possible a reduction in size of the equipment employed.

Abstract: A system and process for controlling a boiler is disclosed. The system includes a television camera mounted above the reciprocable grate of the boiler to locate craters in solid fuel on the grate and an actuator to vary an operating parameter of the furnace according to the location of the craters.

Abstract: This invention relates to an improved method of controlling temperatures within a cleaning or reclamation furnace which is normally used to reclaim metal parts contaminated with combustible materials by pyrolyzing the combustible materials. A reclamation furnace usually includes a primary heat-input burner employed to heat the contaminated parts in the primary heating chamber, an afterburner chamber contained within the heating chamber having a secondary burner to burn volatile gases which are given off by the combustible materials as the parts are heated, and two separately-controlled automatic valve and spray nozzle assemblies connected to the primary heating chamber. Each nozzle assembly is connected to a pressurized water source to deliver a water-spray injection into the heating chamber.

Abstract: A cantilever diffusion tube apparatus includes a quartz cantilever tube having a support end clamped to a laterally movable carriage mechanism and an outer end portion containing a plurality of spaced semiconductor wafers. The cantilever tube is coaxially aligned with a diffusion tube of a diffusion furnace. The support end of the cantilever tube is sealed by a door plate through which a gas tube extends. The wafers are loaded into the cantilever tube through a window opening. The carriage then moves the cantilever tube and wafers therein into the diffusion tube. Reactant gases are caused to flow into the cantilever tube, between the heated wafers therein, and out of the cantilever tube. Then purging gas is caused to flow through the cantilever tube and wafers therein.

Abstract: The heating apparatus according to the invention concerns open circulatory-firing baking furnaces comprising an assembly of chambers which are heated by gases which circulate in hollow partitions (7, 19, 25) which divide the chambers into compartments. The hot gases are produced by fuel injection means (13, 17) which are placed in the upper part of the partitions.In accordance with the invention, instead of the fuel injectors (13, 17) being placed in the same direction as the flow of combustion-supporting gas, the injectors (26, 29) are placed countercurrent, which permits the temperature distribution and the accuracy of the control action to be substantially enhanced.The apparatus is applied in particular to baking carbon anodes which are used in aluminum electrolysis cells.

Abstract: For producing uneven coloring on firing plate-like ceramic material such as tiles or flags in a kiln, more specially a roller kiln, made up of preheating, firing and cooling zones, and through whose oxidizing atmosphere in the firing zone the material to be fired is moved in a single layer without burning tools for supporting it, in or at the end of the firing zone, in a screened-off part of the kiln, the material to be fired is acted upon by a partly reducing atmosphere. In this respect the material to be fired may be passed at this position through a reducing zone and then through a pulsating oxidation zone. It is however possible as well for the material to be fired to be moved through a reducing zone and then purposefully acted upon by blowing with a strongly oxidizing gas. A further possible way of undertaking the process is such that in or at the end of the firing zone the material to be fired is moved in a pulsating reducing zone.

Abstract: Gases are blown into the kiln through its shell by means of shell pipes or nozzle blocks. The rates at which gases actually enter the kiln are ascertained in that the pressure in each supply duct is pneumatically tapped at a constriction and is applied to a transducer, which is secured to the kiln. A differential pressure is ascertained by the transducer and converted to an electric signal, which is delivered to a control station via slip rings, which are secured to the kiln, and stationary taps.

Abstract: A method is disclosed for temperature control in a heating furnace including a step of regulating the emissivity of the flame in the heating furnace. This regulation is accomplished by adjusting the soot content of the flame. The soot content is changed by introducing auxiliary gaseous fuel, i.e., hydrocarbonaceous material, in addition to the main gaseous fuel, into the heating furnace. A heating furnace temperature control apparatus for carrying out this method is also disclosed.

Abstract: A process for firing ceramic bodies, in particular tiles, is disclosed, consisting in conveying the ceramic bodies through an elongated heat treatment chamber, both main faces thereof being freely exposed to heat transmission, simultaneously heating said bodies and the chamber walls by means of a heating fluid, generally combustion gases, the temperature of the portions of the chamber walls which are in view of the ceramic bodies not being higher than that of the heating fluid and controlling the flow of the heating fluid so that its actual volume flow rate, measured axially of the chamber and at the point thereof where the chamber temperature is 900.degree. C., is comprised between 4500 and 12,000, and preferably between 6000 and 10,000 cu.m. per sq.m. of transverse cross-section. Preferably the surface rate of travel of the tiles, when tiles are fired, is comprised between 22 and 30 sq.m. of tile per hour and per linear meter of inner perimeter of the chamber, for 4.5 mm.

Abstract: Hot briquetting apparatus for ferrous or non-ferrous particles has a furnace having upper and lower chambers. The particles are supplied to the lower chamber and leave the lower chamber through a discharge tube to enter a briquetting press. A passage is performed between the lower and upper chambers and sensing means sense the constituents of the gases in that passage. Control means control the air-to-fuel ratio of a zone of the lower chamber. The control means are connected to the output of the sensing means so as to maintain the atmosphere within the zone as a reducing atmosphere, the whole of the lower chamber being a reducing atmosphere.

Abstract: A method and apparatus for drying coal in which the coal is dried by a hot gas and then quickly cooled with ambient air to reduce the oxidation rate and in which the air heated in the cooler is supplied to support the combustion that generates the hot gas. The drying gas exhausted from the dryer is utilized to extract coal product, to produce the fuel necessary to generate the hot drying gas and to provide a tempering gas to help maintain the combustor within a desired temperature range. Condensation of the exhaust drying gas is prevented by utilizing the hot gas discharged from the combustor, bypassing the dryer, and supplying it to the exhaust gas at a plurality of different points.

Abstract: The rate of calcining carbonaceous material in a rotary kiln is increased by introducing oxygen into the inlet of air fans mounted on the kiln. The introduction of oxygen is effected during a predetermined portion of each kiln revolution and is effective to enrich the oxygen content of air supplied to the kiln to approximately 23-25% oxygen. By so enriching the interior kiln atmosphere during calcining of material such as petroleum coke, greater temperatures are obtained than will be obtained by the use of air alone thereby accelerating the evolution and combustion of volatile materials during calcination. The accelerated evolution and combustion of such volatiles enables the rate at which carbonaceous materials can be calcined in a kiln of a predetermined length to be increased.

Abstract: Pellets to be fired are treated with high-temperature gases which, before being supplied to the pellets, are heated by combustion of fuel in a combustion chamber to a temperature above the temperature at which the pellets are to be treated and high enough to ensure that slag formed during combustion can be tapped in liquid form. Cooler gases are then admixed to the high-temperature gases outside the combustion chamber and before they are supplied to the pellets to cool the gases to the temperature desired for the treatment.

Abstract: In the manufacture of clay or refractory ware containing oxidizable material, stacks of the ware are passed through a tunnel kiln and a flow of air passed over the stacks. Fuel burners are operated to provide the necessary stages for firing the ware. These stages include an oxidation stage in which residual oxidizable material is oxidized. Gas containing more oxygen than air (i.e. commercially pure oxygen or oxygen-enriched air) is introduced into the region of the kiln where the oxidation takes place. The oxygen-rich gas is caused to penetrate at least one stack for the time being in the oxidation region so as to increase the concentration of oxygen throughout the individual items of ware within said stack. It is thus possible to oxidize all the residual oxidizable material. At least 50% of such oxidation is typically confined to a temperature range of 100.degree. C. The heat thereby released assists in the firing of the ware.

Abstract: A process for the heat-treatment of fine-grained material which is preheated in a cyclone preheater, deacidified by additional fuel in a precalcination zone, and subsequently calcined to completion in a revolving tubular kiln. The gas temperature in the cyclone preheater and the material temperature after passage through the precalcination zone are measured, the difference between these temperatures is determined and, when the temperature difference reaches a maximum or minimum value, regulation of the fuel supply to the precalcination zone is switched to manual operation. In this way, the amount of fuel is rapidly adapted to the particular circumstances prevailing in the event of disturbances.

Abstract: The opposite ends of a conveyor tunnel furnace are free of physical seals and instead each end is provided with a gas seal tunnel. Each gas seal tunnel is formed by at least two spaced apart, transversely extending fluid flow restriction members defining at least one gas seal chamber therebetween. Gas is supplied in a fixed volumetric flow to each gas seal chamber and maintained at a pressure greater than that of the furnace or of the ambient atmosphere. The flow restriction members are adjustable to cause accelerated gas flow therethrough, or therearound, to prevent mixing or diffusion of gases.

Abstract: The present invention is an improved apparatus and method for directly heat treating articles in a sealed treatment chamber of the heat treatment furnace. A burner means fires into a precombustion chamber which is connected in communication with the treatment chamber. Combustion is completed in the precombustion chamber and the products of combustion are fed into the treatment chamber. Additional treatment gas such as an endothermic gas is fed directly into the furnace treatment chamber.

Abstract: A method for preventing fires and explosions and thus controlling excess temperature within a burn-off or reclamation furnace including a water injection nozzle within the furnace, an automatic valve assembly connected to a source of water under pressure to turn the water on and off, an input burner to heat contaminate materials, an afterburner to burn volatile gases given off by the contaminate materials as they are heated, a temperature sensor located in the discharge from the afterburner to actuate the automatic valve assembly open and closed responsive to the temperature of the discharge, the temperature of the discharge depending on the rate of emission of volatile gases from the contaminate material so that if a high emission rate causes a predetermined temperature to be exceeded the valve assembly opens and the water injection nozzle sprays water on the contaminate materials to cool them and decrease the emission rate until the valve assembly closes.

Abstract: The present invention relates to a method of and an apparatus for controlling the combustibility of volatile hydrocarbons and particulate matter in an exhaust gas stream driven off from a carbon product being baked in a furnace. In a prebaking stage, the carbon product is heat treated in a temperature range of 300.degree. C. to 600.degree. C. in order to drive off the volatile hydrocarbons and particulate matter and form the exhaust gas stream. The exhaust gas stream is heated to a temperature of at least 900.degree. C. and at least one heat transfer medium is force-drafted and mixed into the exhaust gas stream so that the stream contains at least approximately 6% oxygen. The volatile hydrocarbons and particulate matter in the exhaust gas stream are combusted into non-polluting compounds having an opacity less than 40% for exhaustion from the furnace into the outside atmosphere.

Abstract: A process and apparatus are disclosed for controlling losses in volatile working fluid systems. In accordance with the process, the object upon which a work operation is to be effected is sequentially moved from a first sealable chamber to a second such chamber and back to the first chamber. While in the second chamber the object is exposed to a working fluid vapor which elevates the temperature of the object to a level near the boiling point of the working fluid. Thereafter, while still in the second chamber, a substantial portion of the working fluid is drained from the object such that the sensible heat acquired by the object upon its elevation of temperature is sufficient to evaporate working fluid remaining on the object upon its removal to the first chamber. Upon removal of the object to the first chamber the object is thoroughly dried through control of the partial pressure of the working fluid vapor contained within the first chamber atmosphere.

Abstract: An energy conserving process furnace has a recuperator to utilize heat derived from exhaust gases in order to reduce fossil fuel consumption of the furnace. Elongated, enhanced surface ceramic heat exchanger tubes are used in the recuperator to recover heat energy from the exhaust gas. A preferred sealing arrangement is used between the metal and ceramic tubes to contain the combustion air. Heat is added by the recuperator to combustion air used in a fluid fuel burner. The ceramic tubes are provided with vibration protective mechanisms to prolong useful life under severe mechanical vibration encountered in some applications.In a method of operating a slot furnace, exhaust gas is exhausted from a side of the furnace through the slot or a passageway having an elongated horizontal cross section. In the preferred arrangement a second passage or air curtain passageway is positioned adjacent the first passageway to permit proper gas flow through a recuperator.

Abstract: A system for drying and preheating small metallic particles such as chips, turnings, borings and the like to remove volatiles therefrom which includes a dryer working in conjunction with a briquetting press. The dryer includes a drying and preliminary combustion chamber including a revolving drum therein through which the chips pass. The drying and preliminary combustion is heated and is atmospherically sealed and operated with a reducing atmosphere. The volatiles driven from the metallic particles are passed to a combustion completion chamber which is maintained at a temperature sufficient to burn the combustibles and into which air is injected to complete the combustion. The hot metallic particles are thermally insulated and sealed from the atmosphere while being conveyed from the drying and preliminary combustion chamber to the briquetting press where they are compressed into briquettes for subsequent introduction into induction furnaces and the like.

Abstract: Temperature control is often a problem in direct-fired rotary kilns for the pyrolysis of carbonaceous materials wherein at least part of the thermal energy for pyrolysis is obtained by in situ combustion of the pyrolysis gases. The present process and apparatus provides a means by which temperature control, and particularly reduction in intensity of the fireball at the burner end of the kiln and/or moving the fireball away from the burner hood. This is accomplished by (1) controlling the velocity of any burner gases and the velocity of the in situ air (or other oxygen-containing gas) and (2) the distribution of the in situ air at the burner end of the kiln, such that a Craya-Curtet number of at least 0.2, and preferably at least 0.4, is obtained.

Abstract: The method for heating the furnace chamber produces high momentum levels during the heat treating cycle so as to obtain substantially uniform temperature throughout the charge. The method includes initially firing a plurality of high velocity burners at substantially maximum fuel input and in substantially stoichiometric ratio. Thereafter, the fuel input is reduced while maintaining the stoichiometric ratio at least during the high input portion of the cycle. Excess air is introduced external of the combustion zones of the burners on a predetermined signal such as a given fuel input reduction to maintain the desired momentum level within the furnace. The apparatus comprises a high velocity burner having associated therewith an excess air unit for discharging excess air external of the combustion chamber or port block of the burner.

Abstract: A shell gas burner is provided to preheat a kiln wherein the burner can be also used for process axial air and has provisions for retracting the burner for protection from high heat source or extending the burner for ease of replacement.

Abstract: A process for the air drying of a food material, such as a proteinaceous material, is disclosed wherein the drying air is heated by direct contact with a burner in such a manner that the formation of undesirable residues in the proteinaceous material as a result of combustion products from the burner is substantially reduced. The burner is operated by feeding to it a fuel mixture containing a stoichiometric quantity of air for purposes of combustion to avoid the use of drying air for combustion. The burner is also operated to provide a heat output which is sufficient for drying of the proteinaceous material but which does not exceed 800,000 BTU/hr./lineal ft. of burner. The burner is also shielded from the drying air while operated at the necessary firing rate or heat output to substantially avoid aeration of the flame by the drying air.

Abstract: Uniform heat treatment of particulate material of nonuniform gradation in a vertical heat treating vessel such as a vertical kiln or retort is affected by regulating the heat input to a heat treating zone in the vessel in response to changes in specific gravity of the mass of particles passing into the heat treating zone as detected by measurements such as differential pressure changes of combustion supporting fluid and process gas flowing into and from the heat treating zone to result in a balance between particulate mass flow and heat input and substantially uniformly heat treated particulate material.

Abstract: A drying plant utilizing a flame jet comprises a jet burner supporting device which is provided over a treatment tank, and a sound arresting device which is formed at a burner inserting port in the upper surface of the treatment tank. A jet burner drawn out of the treatment tank is inclined to bring the fore end of the burner close to an ignition device, thus to ignite the burner. While observing the ignited burner externally through a transparent tube, combustion is controlled to establish the perfect combustion. Loud noises at the adjustment of the combustion are prevented by the sound arresting device from being given forth to the outside. A matter to-be-dried, such as paper manufacture sludge, supplied into the treatment tank is crushed by flames of the jet burner at high temperature and at high speed without being burnt. The treated matter is taken out as the dried matter.

Abstract: Burners of an oven are operated to satisfy heat loads changeable between a high load and substantially smaller loads. At least under the smaller loads the burners are cyclically controlled in a cycle of time periods T-1 and T-2. During the periods T-1 the burners are steadily regulated to maintain a uniform temperature in the oven. For periods T-2 the burners are periodically controlled to admit one of two selected magnitudes of fuel flow to the oven. At least under the smallest loads the latter magnitudes are periodically controlled to be zero or close to zero.

Abstract: In the calcination of petroleum coke in a rotary kiln, procedure wherein air is controllably supplied internally of the kiln to burn the removed volatiles, as by selection or adjustment of the amount of such air and of the speed of coke travel down the kiln, so that all or nearly all of the heat for calcining the coke is provided by such combustion, and so that a suitably high temperature is reached for effective calcination at an efficiently large feed rate of coke, a special feature being to maintain a significantly long travel time of the coke from a region of intense calcining activity to the product discharge end of the kiln. High production rates, of coke calcined well and uniformly, are economically attained, with ease of control and with unusual stability of kiln operation.

Abstract: In vertical continuous furnace calcining of lime, dolomite, magnesite, or the like, part of the air which is introduced at the lower end of the furnace chamber is drawn off in the area of the cooling zone within the chamber and is then reintroduced in encompassing relation into the material column in the firing zone within the furnace chamber and which is located immediately above the cooling zone, the remainder of the air flowing up through the column of material being treated in the chamber. Cleaning of the withdrawn cooling air and addition of fresh air are provided for.

Abstract: A calcining method and apparatus are provided wherein material to be treated is fed into the top of the furnace and the finished material discharges from the bottom of the furnace and cooling and combustion air enters under forced draft through the bottom of the furnace and flows upwardly through the column of material. A part of the fuel supply is delivered to the region between an upper preheating zone in the furnace and a subjacent combustion or firing zone and the balance of fuel required for firing is introduced into the combustion zone about its periphery. Provision is also made for bypassing part of the cooling air from a lower cooling zone to the combustion zone, with intermediate cleaning of the bypassed air.

Abstract: A method and apparatus for warming thermoplastic articles such as eyeglass frames quickly up to the softening temperature of the thermoplastic, but not exceeding the temperature at which degradation of the thermoplastic would take place by means of temperature controlled infrared radiators and also preferably using a body of heated air to blanket the thermoplastic article from ambient air.