Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
  • F27B13/00—Furnaces with both stationary charge and progression of heating, e.g. of ring type or of the type in which a segmental kiln moves over a stationary charge
  • F27B13/06—Details, accessories or equipment specially adapted for furnaces of this type
  • F27B13/14—Arrangement of controlling, monitoring, alarm or like devices
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
  • F27B13/00—Furnaces with both stationary charge and progression of heating, e.g. of ring type or of the type in which a segmental kiln moves over a stationary charge
  • F27B13/02—Furnaces with both stationary charge and progression of heating, e.g. of ring type or of the type in which a segmental kiln moves over a stationary charge of multiple-chamber type with permanent partitions; Combinations of furnaces
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D21/00—Arrangement of monitoring devices; Arrangement of safety devices
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D21/00—Arrangement of monitoring devices; Arrangement of safety devices
  • F27D21/04—Arrangement of indicators or alarms
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D21/00—Arrangement of monitoring devices; Arrangement of safety devices
  • F27D2021/0057—Security or safety devices, e.g. for protection against heat, noise, pollution or too much duress; Ergonomic aspects

Definitions

• the present invention relates to a method and a system for controlling the operation of a plant for firing carbonaceous blocks, in particular carbon anodes used for the production of aluminum by electrolysis.
• the invention aims to detect a dysfunction related to a combustion problem, and particularly the combustion problems either for lack of oxidant, or lack of ignition temperature, or by too much fuel (compared to the oxidant ).
• Aluminum metal is produced industrially by electrolysis according to the Hall-Héroult process.
• tanks having at the bottom a cathode assembly and containing an electrolysis bath in which anodes made of carbon material are partially immersed.
• the anodes are formed of molded carbon blocks that are fired in kilns.
• these furnaces comprise an insulated outer enclosure, which may comprise transverse walls defining chambers.
• the furnaces are provided with hollow heating partitions extending longitudinally, forming between them elongated cells intended to receive the carbon blocks for their cooking.
• dust serves to protect the anodes during cooking, in particular the oxidation they could undergo due to the high cooking temperature (of the order of 1200 0 C).
• the cooking is obtained by hot gases circulating inside the partitions. These gases comprise on the one hand air blown into the partitions by means of blowing legs and a primary fuel - liquid or gaseous - injected into the partitions, and on the other hand the gas produced by the firing of the anodes (hydrocarbons volatiles), which serves as a secondary fuel
• the injection of the primary fuel can be done by heating ramps comprising one or more burners, or one or more injectors. In the latter case, the fuel burns in the oven because of the high temperature that prevails. Then the injected gases and / or products are sucked from the partitions by means of suction legs. During a cooking cycle, the heating ramps are progressively displaced relative to the oven, so that each anode charge, at a given location of the oven, is successively preheated, subjected to cooking and then cooled. This type of furnace is called “ring furnace"("ringfurnace” in English). Once the anodes have cooled, they are evacuated out of the cells.
• the present invention aims to remedy the disadvantages mentioned above, by providing a method and a system for detecting a furnace malfunction related to a combustion problem that meets reliable safety standards, which makes it possible to detect very quickly a problem of localized scanning on a wall of the oven.
• the invention relates to a method for controlling the operation of a carbonaceous block cooking installation, the installation comprising:
• an oven which comprises longitudinal hollow partitions in which hot cooking gases can circulate and defining between them cells for receiving the carbonaceous blocks to be cooked
• a heating system rotating relative to the furnace which comprises an upstream ramp of several air blowing legs in the different partitions, a downstream ramp of several gas suction legs from the different partitions and, between said ramps blowing and suction, at least one heating ramp provided with at least one burner or at least one fuel injector per partition; generally longitudinal gas flow lines being thus defined along the partitions between a blowing leg and a corresponding suction leg.
• the method comprises: a) for each circulation line of gas, the continuous recording, in at least one given point of said gas flow line, of at least one parameter measured among the temperature, the pressure, the flow rate, the oxygen concentration and the concentration of carbon monoxide ; (b) continuous evaluation of at least one factor from the measured parameter (s); c) the continuous comparison of this factor with a corresponding reference value d) remission of a malfunction signal when the comparison between the factor and the corresponding reference value does not meet predefined security criteria.
• the method therefore provides for continuously performing one or more measurements of physical parameters, and this for each of the rows of partitions, and not in a single global or localized way. Then, a relevant factor is evaluated. In some embodiments, this factor can be calculated and, in other embodiments, this factor can be directly the measured parameter, no calculation being necessary then. This factor can correspond to an index of operation of the oven.
• This factor is then compared to a reference value.
• This can be predetermined (for example depending on the operating conditions) or calculated (it can be in particular the average of the other identical factors on the other gas circulation lines). If the factor considered is not in the predetermined safety range (for example if it is below the low threshold value or above the corresponding high threshold value, or if it deviates too much of this reference value), then a malfunction signal is issued and, preferably, operations to secure the installation are implemented in response to this signal.
• the invention provides the possibility of combining different factors and the associated reference values to increase the safety of the installation.
• the different securities are independent of each other.
• the invention makes it possible in particular to detect a scanning problem of a line of partitions, that is to say a problem of circulation of the gas in and through the hollow partitions.
• upstream and downstream are defined with respect to the direction of fire, which is also the direction of movement of the gas flow.
• the invention also relates to ovens having at least one transverse wall and those that do not.
• PN natural preheating zone
• HR heating zone
• blowing zone located downstream of the heating ramp or ramps.
• At least one parameter is measured in a natural preheating zone (PN) or a heating zone (HR), and at least one parameter is measured in a blowing zone (BL).
• PN natural preheating zone
• HR heating zone
• BL blowing zone
• the parameter measured in the blowing zone (BL) is the pressure at a zero point ramp which is arranged to regulate the pressure at the junction of the blowing zones (BL at atmospheric pressure substantially). ) and heating zones (HR).
• At least one evaluated factor is directly a measured parameter, which makes it possible in particular to avoid any calculation.
• at least one evaluated factor may be a function of at least two parameters, for example the product and / or the quotient of at least two parameters.
• - T is the temperature at a point of a gas flow line
• - P is the pressure at a point in a gas flow line
• Q is the flow of gas at a point in a gas flow line
• - PO is the pressure measured at a zero point ramp which is arranged to regulate substantially at atmospheric pressure the pressure at the junction of the blow zones (BL) and the heating zones (HR);
• At least two distinct factors are evaluated, and each of these factors is compared to a distinct corresponding reference value.
• particularly robust and simple to implement is measured and recorded only the temperature, preferably in each suction leg.
• the postman The evaluated value and the reference value are then advantageously directly temperatures.
• the reference value of a given factor can be an average (typically the algebraic average) or the median of the factors evaluated for all or part of the gas flow lines.
• the calculation of the reference value it is possible, for the calculation of the reference value, to exclude at least one of: the monitored gas flow line; a gas circulation line located at one end of the ramps in the transverse direction; and the gas flow line for which the factor is farthest from the mean or the median.
• control method may comprise, in response to the emission of the malfunction signal, the triggering of measures to secure the installation.
• safety measures are triggered when the factor in a gas flow line considered deviates in a given direction from a reference value, typically when said factor is lower than said reference value.
• safety measures are triggered when the relative difference between the factor in a considered gas flow line and the reference value is, in absolute value:
• N is a real number between 2 and 3;
• N 'times ⁇ (where ⁇ is the standard deviation and N' is a real number typically between 2 and 3) of the reference value.
• the safety measures are triggered only when said relative deviation deviates in a given direction from the reference value, typically when said deviation is negative (that is to say typically when the factor in a line gas circulation considered is less than the reference value).
• the pressure is measured at a zero point ramp located in the blowing zone (BL), said zero point ramp being arranged to regulate substantially at the atmospheric pressure the pressure at the junction of the blowing zones (BL) and the heating zones (HR), and safety measures are triggered when a time average of the differences between said measured pressure and a reference value (typically a set value) becomes, in absolute value, greater than a predetermined fixed threshold.
• a reference value typically a set value
• the safety measures are triggered only when said time average deviates in a given direction from the reference value, typically when it is negative, that is to say typically when the measured pressure is in average less than the reference value.
• Said time average observed for each gas flow line may optionally be compared with the values observed for all or part of the other gas flow lines in order to trigger if necessary safety measures.
• time average is a moving average over the previous m measures, where m is between 3 and 10.
• the invention relates to a system for controlling the operation of a carbonaceous block cooking installation, the installation comprising: an oven which comprises longitudinal hollow partitions in which hot cooking gases can circulate and defining between them cells for receiving the carbonaceous blocks to be cooked,
• a heating system rotating relative to the furnace which comprises an upstream ramp of several air blowing legs in the different partitions, a downstream ramp of several gas suction legs from the different partitions and, between said ramps blowing and suction, at least one heating ramp provided with at least one burner or at least one fuel injector per partition; generally longitudinal gas flow lines being thus defined along the partitions between a blowing leg and a corresponding suction leg.
• the system comprises: means for continuously measuring and recording at least one parameter, at least one given point of each line of gas circulation, among: temperature, pressure, flow rate, oxygen concentration and carbon monoxide concentration;
• - Analysis means able to continuously evaluate at least one factor from the measured parameter (s) and to continuously compare this factor with a corresponding reference value;
• alert means able to emit a malfunction signal when the comparison made by the analysis means does not meet predefined security criteria.
• the malfunction signal is typically an electrical or opto-electrical signal, which may possibly cause automated actions and / or generate a sound or light alert signal to cause manual or semi-automated actions.
• Figure 1 is a partial view, in perspective, of a typical anode baking installation and more particularly the furnace of this installation;
• Figure 2 is a top view of the oven, also showing a typical heating system
• Figure 3 is a schematic side view of the partitions located at the level of the heating system of Figure 2;
• FIGS 4, 5, 6, 8 and 10 show temperature values measured during testing. More specifically, these figures are graphs showing a change in the temperature of the gases measured at a temperature and pressure measurement ramp (TPR:
• Temporal and Pressure Ramp in natural preheating zone (PN) as a function of time, when different partitions of the same gas circulation line are plugged (the order of the figures corresponds to the distance of the blocked partition by ratio to the suction ramp);
• FIGS. 7, 9 and 11 are graphs showing an evolution of the temperature / pressure quotient at the TPR as a function of time, respectively corresponding to the situations of FIGS. 6, 8 and 10;
• Figures 12 and 14 are graphs showing an evolution of the pressure measured at a zero point ramp as a function of time, when different partitions of the same gas circulation line are clogged;
• FIGS. 13 and 15 are graphs showing the evolution of the cumulative time average of the deviations from the set point of the pressure measured at the level of the zero point ramp as a function of time, respectively corresponding to the situations of FIGS. 12 and 14.
• An anode baking plant comprises a furnace 1 with a rotating fire.
• the following detailed description relates to the application of the invention to installations comprising a chamber furnace, as illustrated in FIGS. 1 to 3.
• the invention is however not limited to this type of furnace.
• the invention is also applicable to installations comprising an oven without intermediate transverse walls between the end walls.
• the furnace 1 comprises an insulated enclosure 2 of substantially parallelepiped shape, with respect to which one defines a longitudinal direction X and a transverse direction Y.
• the chamber 2 In the chamber 2 are arranged transverse walls 3 defining successive chambers C in the direction X.
• each chamber C are provided hollow partitions 4 arranged in the longitudinal direction, forming between them elongate cells 5.
• Each chamber C thus comprises several partitions 4a to 4i, as illustrated in FIG.
• the partitions 4 comprise thin lateral walls 6 generally separated by spacers 7 and baffles 8.
• the ends of the hollow partitions comprise openings 10 and are embedded in notches 9 of the transverse walls 3. These notches 9 are themselves provided with openings 10 'located opposite the openings 10 of the partitions 4, to allow the passage of gas flowing in the partitions 4 from one chamber C to the next.
• the partitions 4 further include orifices 11 which serve in particular to introduce heating means (such as injectors or fuel burners), or suction legs 12 of a suction ramp 13 connected to a main duct 14 along the furnace 1, or air blower legs, etc.
• the chambers C form a long span 15 in the longitudinal direction, and the furnace 1 typically comprises two parallel spans, each having a length of the order of one hundred meters, delimited by a central wall 16.
• the furnace 1 typically comprises two parallel spans, each having a length of the order of one hundred meters, delimited by a central wall 16.
• the cells are stacked green carbon blocks 17, that is to say the anodes to be cooked, and the cell 5 is filled with a granular material or powder (typically coke), called "dust" 18, which surrounds these blocks 17 and protects them during their cooking.
• a granular material or powder typically coke
• the anode cooking installation also comprises a heating system, which typically comprises: an upstream blowing ramp 19 of several air blowing legs 20 in the various partitions 4 of a chamber C (through the orifices 11) , two or three heating ramps 21, 22, 23 each composed of one or two burners or fuel injectors per partition, and a downstream suction ramp 13 of several suction legs 12 of gas from the different partitions 4 d a chamber C (from the orifices 11).
• a heating system typically comprises: an upstream blowing ramp 19 of several air blowing legs 20 in the various partitions 4 of a chamber C (through the orifices 11) , two or three heating ramps 21, 22, 23 each composed of one or two burners or fuel injectors per partition, and a downstream suction ramp 13 of several suction legs 12 of gas from the different partitions 4 d a chamber C (from the orifices 11).
• the various components of the heating system are arranged at a distance from one another according to the following typical fixed configuration: the air blowing ramp 19 is located at the inlet of a given chamber C1 ; the first ramp 21 of burners / injectors is disposed above the fifth chamber C5 downstream of the air blowing ramp 19, the second ramp 22 of burners / injectors is disposed above the chamber C6 located immediately in downstream of the first ramp 21; the third ramp 23 of burners / injectors is disposed above the chamber C7 located immediately downstream of the second ramp 22; and the suction ramp 13 is located at the outlet of the third chamber C10 downstream of the third ramp 23.
• the relative position of the various elements is always the same (ie, in the direction of fire, the blowing ramp 19, the burner / injector ramps 21, 22, 23 and the suction ramp 13).
• the spacing (in number of chambers) between elements can vary from one oven to another.
• the first ramp 21 of burners / injectors could be positioned above the chamber C4 or C3.
• the suction ramp 13 could be located at the outlet of the second chamber downstream of the third ramp 23.
• a blowing leg 20 and a corresponding suction leg 12 there is therefore a generally longitudinal gas flow line 24 along the successive partitions 4.
• generally longitudinal is meant that the gas flows from a blowing leg to the corresponding suction leg, in the X direction globally, while performing locally vertical movements, typically in waves, as shown in FIG.
• the gaseous flow consists of air, the gas resulting from the combustion of the injected liquid or gaseous fuel, and the volatile matter released by the carbonaceous blocks.
• the heat produced by the combustion of the fuel heating (primary) and volatile matter (secondary fuel) released by the carbonaceous blocks is transmitted to the carbon blocks 17 contained in the cells 5, which leads to their cooking.
• a firing cycle of carbon blocks, for a given chamber C typically comprises the loading of the cells 5 of this chamber C into green carbonaceous blocks 17, the heating of this chamber C to the firing temperature of the carbonaceous blocks 17 (typically from 1100 to 1200 ° C.), the cooling of the chamber C to a temperature which makes it possible to remove the burned carbonaceous blocks and the cooling of the chamber C to the ambient temperature.
• the principle of the rotating light is to successively carry out the heating cycle on the furnace chambers by a displacement of the heating system.
• a given chamber passes successively by periods of natural preheating (by the hot gases circulating in the partitions), forced heating (including forced preheating) and cooling.
• the cooking zone is formed by all the chambers located between the blowing ramp and the suction ramp.
• Figures 2 and 3 shows the direction of the fire F.
• the first four chambers C1 to C4 according to the blowing ramp 19 are so-called blowing zones BL 1 respectively BL4, BL3, BL2 and BL1.
• blowing zones BL 1 respectively BL4, BL3, BL2 and BL1.
• the anodes placed there are already cooked, and undergo a cooling, which has the consequence of increasing the temperature of the blown air, which will be used for combustions.
• the following six chambers C5 to C10, up to the suction ramp 13, are depressed areas.
• Substantially at the junction between these two blocks of chambers is the "zero point" PO, that is to say a point where the pressure in the furnace 1 is substantially equal to the atmospheric pressure.
• the zero point is located upstream of the first heating ramp to avoid the release of combustion products into the environment.
• a pressure takeoff ramp - so-called zero point ramp (PZR) - is provided to regulate the pressure at the zero point.
• This ramp 25 is fixedly positioned relative to the heating system, upstream of the first heating ramp 21, in the blowing zone BL.
• the zero point ramp 25 is located at the openings 11 of the partition 4 located further downstream of the last chamber C4, BL1 located in the blowing zone.
• this zero point ramp could be placed at another point in the blast zone BL.
• the temperature of the preheated air in BL blow zones is sufficient to create ignition and fuel combustion; - a PN natural preheating zone at room level
• the heating system also comprises a temperature measuring device, which typically comprises at least one pyrometer or a thermocouple 26 per heating ramp and per partition, each disposed immediately downstream of each heating ramp 21, 22, 23.
• TPR pressure and / or temperature measuring ramp 27
• This ramp is positioned at the same chamber C10 as the suction ramp 13, that is to say in the first natural preheating chamber PN1, for example in the opening 11 upstream of this chamber.
• the pressure and the temperature can be measured at distinct locations in the natural preheating zone.
• the measurement of the temperature is carried out in PN1, while the pressure measurement can be carried out at any point in the PN zone.
• measuring ramp 27 or “TPR” will be used to refer to the measurement of temperature and pressure, possibly in separate locations, in the PN area.
• the main objective of the method for detecting a malfunction of this installation is to quickly detect the blockage, even partial, of a partition, leading to a problem of scanning this partition, that is to say to a circulation of degraded or non-existent gas flow. Once such a problem is detected, it is a matter of triggering the appropriate actions for the security of the installation and its restart as quickly as possible, under the required security conditions.
• the method comprises: - the continuous recording of one, or advantageously at least two, physical parameters related to the furnace and the circulating gases for each line of partitions (pressure, temperature, flow rate, oxygen concentration, carbon monoxide concentration);
• the method preferably further comprises initiating a safety operation following the emission of a malfunction signal.
• Said security operation may comprise at least one operation chosen from:
• the suction flaps of the considered partition line up to their maximum as long as no impact on the other partition lines is detected (this impact being an opening reaction of the suction flaps other partition lines due to a loss of flow in these partition lines). If the suction flap of at least one of the other partition lines is already open to the maximum, the opening of the suction flap of the clogged partition line is preferably not modified to avoid the risk of reducing the sweeping of the line of partitions whose flap is open to the maximum.
• the suction flap is a member present in each suction leg, acting as a valve, and to adjust the flow (or pressure) in these legs.
• the primary fuel injection into the relevant partition line preferably resumes after the problem has been solved (uncoupling of the defective partition) and the installation is secured.
• the safety criterion relates to the temperature of the gases measured in the natural preheating zone PN, for example in the suction legs 12 or at the measurement ramp 27 (TPR).
• the temperature T is measured and recorded in each suction leg 12, that is to say independently for each line of longitudinal partitions.
• the temperature in a given suction leg 12, for example for the partition 4c is compared in real time with an average (typically an algebraic average), or the median, of the temperatures of the other partitions by eliminating or not the partitions. 4a, 4i or the temperature furthest from this mean or median.
• a malfunction signal is emitted. Concretely, according to different embodiments, this occurs if the relative difference between the temperature of the suction leg 12 considered and the average (or median) calculated temperatures in the other legs suction is, in absolute value :
• a fixed threshold for example 50 0 C
• N is a real number typically between 2 and 3
• N 'times ⁇ (where ⁇ is the standard deviation and N' is a real number typically between 2 and 3) of the mean (or median) calculated.
• Said relative deviation is typically negative in the case of a malfunction of combustion in a line of partitions.
• This temperature measurement is carried out for each line of partitions, independently, so that a blockage of any one of the partitions can be detected quickly.
• a special treatment of the external partitions 4a, 4i could be envisaged.
• This embodiment is robust, very responsive and very simple. It allows to detect with significant sensitivity a partition clogged in the natural preheating zone (PN) without difficulty, and optionally without calculation if desired, even when the control system reacts. With this embodiment, it is also possible to detect a clogged partition in the zone of the heating ramps (HR) according to the importance of the clogging and the reaction of the control system.
• Figures 8 and 10 respectively illustrate the case of the partition 4a plugged HR2 and the partition 4a plugged HR3. It can also be seen that the temperature of the partition concerned is lower than the others, with a smaller difference compared to the previous cases.
• the safety criterion relates to the quotient T / P where T is the gas temperature measured in the PN zone, for example in the suction legs 12, and P the pressure also measured in the zone PN, for example at the ramp 27.
• T is the gas temperature measured in the PN zone, for example in the suction legs 12, and P the pressure also measured in the zone PN, for example at the ramp 27.
• P the pressure also measured in the zone PN, for example at the ramp 27.
• This embodiment has the same advantages as those of the first embodiment.
• the detection of a partition is improved plugged in the zone of the heating ramps 21, 22, 23 (HR1, HR2, HR3) when an automatic or manual action is performed to increase the suction of the line considered, as seen in FIGS. , 9 and 11.
• the safety criterion relates to the pressure in the PN zone, and more specifically to the pressure or the pressure gradient at the micro-venturis present in the suction legs 12.
• a pressure tap is made at the inlet of the venturi and a pressure tap is made in the neck of the venturi .
• a first pressure switch is triggered if the vacuum at the inlet of the venturi is too low (this being the sign of a draw problem).
• a second independent pressure switch is triggered if the pressure differential between the inlet and the neck of the venturi is too low (this being a sign of a low flow).
• the main advantage of this embodiment is that it uses a mechanical trigger, and therefore there are no electrical transmissions or calculations to be done.
• the safety criterion relates to the flow of gas in the PN zone, and in particular the suction leg 12 of each line of partitions, and more particularly to the detection of a low flow rate threshold.
• the calculated flow may be standardized. Security is more efficient if the calculated flow is the actual flow. Similarly, security is more effective when the low flow threshold varies over time. Indeed, in normal operation, the flow is not constant but varies during a cooking cycle.
• This embodiment is advantageous in that it is based on the flow rate, which is the most representative image of a scan (that is to say a fluid flow in the partitions).
• the safety criterion relates both to the flow rate Q (for example calculated as indicated above for the fourth embodiment) and to the temperature T of the gases measured in the zone PN, for example in the suction legs 12. It is possible to have two independent security on these two parameters
• This difference can be, for example, the standard deviation of the reference value (ie an average of the other partitions) or the average deviation from the average of the other partitions.
• the safety criterion relates both to the flow rate Q (for example calculated as indicated above for the fourth embodiment) and to the quotient T / P where T is the measured gas temperature. in the PN zone, for example in the suction legs
• Cp is the heat capacity of the gas, depending on the temperature.
• T is the gas temperature measured in the PN zone, for example in the suction legs 12, and TO is a reference temperature. If the temperature drops due to clogging, Cp also drops, which reinforces the decrease in enthalpy. This gives a greater sensitivity.
• An eighth embodiment based on the seventh, makes it possible to improve the sensitivity of the measurement by taking into account the pressure P measured at the level of the ramp 27.
• the factor to be compared with a reference value is therefore H / P, where H is calculated as indicated above.
• This eighth embodiment is advantageous in that it makes it possible to improve the detection of a partition clogged under the heating ramps (zones HR1, HR2, HR3).
• the safety criterion relates to the pressure measured at the zero point ramp (PZR), that is to say at the "zero point pressure" PO.
• the reference value to be considered is the average time of the deviations from the set pressure for the line considered. Indeed, in normal operation, this average is very similar from one partition line to another; it reaches a value close to 0 Pa early in the cooking cycle, then varies little during a cooking cycle.
• the safety measures are triggered when the average time difference of the pressure P at the zero point of the partition considered is negative and less than a low threshold of negative difference (for example -10 Pa).
• the time average can be an average of the measurements since the beginning of the cycle.
• the time average is a moving average over a number of previous measurements, typically the last 5 measurements, to increase the reactivity of the detection.
• the safety criterion is the value of the PO pressure at the zero point. This value makes it possible to detect a wall clogging problem or a problem of control of the air blowing by the blowing ramp 19 by defining a low threshold of the order of -10 Pa.
• This embodiment is very simple, robust and responsive. It is particularly efficient and effective for detecting a clogged partition at the BL blowing zone because it adapts to all systems (zero point regulation or fixed blowing). This embodiment also makes it possible to detect a partition clogged under the heating ramps.
• FIG. 12 which shows the pressure measured at the zero point on the various lines of partitions
• the pressure difference at the setpoint is more important.
• the detection can be further refined, since this average makes it possible to eliminate the variations in time of the deviations from the setpoint, so that the difference between the partition lines functioning normally and the line of partitions having the partition clogged becomes more linear and constant.
• Figures 12 and 13 do not show the values concerning the partition 4h because, unlike the other partitions, this partition 4h was not, during the test, automatically regulated, and the values obtained do not are therefore not significant.
• Figures 14 and 15 are the equivalents, respectively, of Figures 12 and 13, in the case where the clogged partition is the partition 4a of the chamber BL2.
• a tenth embodiment provides for placing at least one analyzer 02 and / or CO by fire, each partition being connected to this analyzer.
• This analyzer is generally placed in the PN zone, downstream of the heating ramps, typically at the PN1 or PN3 chambers or in the suction legs. For example, when a single analyzer is used, the analyzer scans each partition successively for 10 minutes, for example, to take the gas and perform an analysis, throughout the cooking cycle. If the O2 level becomes too low and / or the CO level is too high, the security is triggered.
• This embodiment is effective for check that the fuel injected by the heating ramps 21, 22, 23 (in HR1, HR2, HR3) burns well.
• a particularly advantageous embodiment of the invention consists in combining a first safety criterion relating to the pressure P at the zero point PO and one or more other safety criteria. It can be any of the embodiments above. This makes it possible to simply detect a blockage at any point between the blowing ramp and the suction ramp, since the criterion PO is particularly effective for detecting a blockage in the blowing zone BL and the other criterion or criteria are particularly effective for detecting a blockage in the HR and PN zones.
• the safety criterion relates to both the pressure P at the zero point PO and the temperature T of the gases measured in the PN zone, in particular in the suction legs 12.
• This is an embodiment particularly simple and effective. Due to the monitoring of the temperature T, it is possible to detect a clogged partition in the natural preheating zone (PN) and in the zone of the heating ramps (HR); in addition, because of the monitoring of the pressure P at the zero point PO, it is possible to detect a partition clogged in the blowing zone (PN). Thus, all oven 1 is safe.
• the pressure factors P can be combined at the zero point PO and the quotient T / P (see the second embodiment).
• the invention provides a decisive improvement to the prior art, by providing a method for detecting a malfunction of an anode baking installation that allows the detection of a local plugging, that is to say clogging of a particular bulkhead, anywhere between the blower ramp and the suction manifold.
• This result is achieved by measuring and monitoring, continuously, local parameters for each line of partitions.
• a system for measuring a global parameter there is no compensation effect that would hide the existence of a problem.
• the invention is not limited to the embodiments described above as examples but that it encompasses all the variants.

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• Engineering & Computer Science (AREA)
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• General Engineering & Computer Science (AREA)
• Regulation And Control Of Combustion (AREA)
• Furnace Details (AREA)
• Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)

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• 2008
  • 2008-12-24 FR FR0807452A patent/FR2940417B1/fr not_active Expired - Fee Related
• 2009
  • 2009-12-08 CA CA2747693A patent/CA2747693A1/fr not_active Abandoned
  • 2009-12-08 CN CN200980152676XA patent/CN102265108A/zh active Pending
  • 2009-12-08 EP EP09801219A patent/EP2379974A1/de not_active Withdrawn
  • 2009-12-08 AU AU2009332809A patent/AU2009332809B2/en not_active Ceased
  • 2009-12-08 BR BRPI0923715A patent/BRPI0923715A2/pt not_active IP Right Cessation
  • 2009-12-08 US US13/142,023 patent/US20110311930A1/en not_active Abandoned
  • 2009-12-08 WO PCT/FR2009/001394 patent/WO2010072907A1/fr not_active Ceased
  • 2009-12-08 RU RU2011130889/02A patent/RU2524293C2/ru not_active IP Right Cessation
  • 2009-12-21 AR ARP090105013A patent/AR074829A1/es not_active Application Discontinuation
• 2011
  • 2011-06-10 ZA ZA2011/04350A patent/ZA201104350B/en unknown

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