FR2880688A1 - Combustion gas monitoring device for e.g. gas fired boiler, has detection unit to control gas passage from one chamber with infrared ray sensor to another chamber with electrochemical sensors if gas concentration does not cross preset value - Google Patents

Abstract

The device has a withdrawal unit to supply combustion gas to an analysis chamber (100) with an infrared ray sensor to provide a signal representing combustion gas concentration in the chamber. A detection unit controls passage of the gas from the chamber to a chamber (110) if the concentration does not cross a preset value. The chamber (110) has electrochemical sensors to provide a signal representing concentration in the chamber (110). The withdrawal unit cools the combustion gas before its input in the chamber (100). An independent claim is included for a combustion gas monitoring method.

Description

METHOD AND DEVICE FOR MONITORING COMBUSTION GAS

  The present invention relates to a method and a device for monitoring a combustion gas. It applies, in particular, to the monitoring of boilers in order to trigger an alarm if the content of CO2, NO2, CO or O2 in the flue gases is higher than the values authorized by the standards in force.

  Document KR9609608 (1994) discloses an apparatus for detecting polluted smoke in combustion gases of a boiler or an automobile comprising a transmitter and a light receiver and a relay controlled by the variation of light received by the receiver of light.

  GB2264170 (1992) discloses an infrared detection gas detector which uses a plurality of infrared emitters emitting different wavelengths and optically coupled to at least one infrared detector through a cavity which contains the gas to be analyzed. The infrared emitters operate sequentially for the detector to provide gas characteristics sequentially.

  US6469303 (2000) discloses a sensor which comprises a metal tube, an electronic card positioned at one end of the tube, a diffusion filter which is positioned at the other end of the tube and an optical system which comprises an infrared source on the electronic board and a mirror on the inner wall of the tube to reflect and focus the light rays on a detector. The detector comprises a signal detector and a reference detector.

  WO2004042374 (2002) discloses a gas sensor which comprises a chamber for receiving gas, a light source, for example infrared, and detectors sensitive to the light emitted by the light source. Light travels along a first optical path to a first detector and along a second optical path to a second detector. The lengths of the optical paths may be equal and focusing mirrors may be provided in the chamber.

  Document GB2035552 (1978) provides an infrared light source on one side of a gas flow, a detector separated from the infrared source by the gas flow and a measurement circuit which measures on the one hand a direct light from the source and, on the other hand, a light passing through the gas stream and, after comparison, a measurement of the desired amount of gas in the gas stream. The result can be used to trigger an audible or visual alarm or a change in the operating conditions of a boiler.

  US6,075,246 (1997) discloses an infrared measurement system having an extended measurement spectrum with an infrared source and an infrared detector. A first optical path, direct, connects the source and the detector and a second optical path, longer, with a reflection allows the measurement of gas content.

  GB2113833 (1982) discloses an infrared analysis apparatus which comprises a source, a wheel which carries a reference cell and two measuring cells, a gas analysis chamber and infrared detection means. The reference cell contains a reference gas that does not absorb infrared and the measurement cells contain a gas that has different levels of infrared absorption. The gas analysis chamber is filled with a sample of the gas to be analyzed and the detection means detects the three-level radiation intensity, after the rays have passed through the reference cell, after the rays have passed through one of the measuring cells and its gas sample and after the rays are passed through the other measuring cell and its gas sample. With these three levels, a gas concentration measurement with compensation for the effects due to temperature variations is obtained.

  US 4,281,248 (1979) discloses a means for reducing the cross sensitivity of a two infrared ray analyzer. It uses two cells of different lengths in the gas sample for the optical paths of the two radii.

  US 5,077,469 (1989) describes a method of calibration and compensation for a non-dispersive infrared gas analyzer. An infrared ray source, a measuring path, a reference path, a modulation system and a differential pressure detector are used and comprise the following steps: - before the measurement, the reference gas which has a concentration variable in the measurement component is sent in the reference path and in the measurement path and the detector is initialized; - Then a dual calibration chamber is placed in both paths while they are crossed by the reference gas, one of the chambers having a particular concentration of the gas to be measured and the other not having the gas to be measured. ; the sensitivity and the amplification of the detector are adjusted; the reference gas continues to flow into the reference chamber while the gas to be measured passes through the measuring chamber.

  US 3,922,551 (1974) describes a gas concentration determination system in which an infrared source emits radiation into a chamber containing a sample of mixed gases. The gas is subjected to density modulation by a piston that compresses or pressurizes it. The amount of radii passing through the gas is measured and the gas concentration is determined as a function of the change of radii received by the detector.

  None of these systems has good reliability. In addition, these systems are very expensive, because of their complexity of implementation.

  The present invention aims to remedy these disadvantages.

  For this purpose, the present invention aims, in a first aspect, a flue gas monitoring device, characterized in that it comprises: - combustion gas sampling means adapted to feed a first analysis chamber in combustion gas; a first analysis chamber provided with a first sensor adapted to provide a signal representative of the concentration of at least one gas in the combustion gas present in the first analysis chamber; a crossing detection means of a predetermined value by said concentration adapted to control the passage of the combustion gas from the first to a second analysis chamber if said predetermined value is not exceeded and the second chamber analysis provided with at least a second sensor adapted to provide a signal representative of the concentration of at least one gas in the combustion gas present in the second chamber.

  Thanks to these provisions, each sensor present in the second chamber is protected against an excess concentration of each gas detected in the first chamber.

  According to particular features, the sampling means are adapted to cool the combustion gas before entering the first analysis chamber.

  Thanks to these provisions, the reliability of the gas concentration measurement in the first analysis chamber is improved.

  According to particular features, the sampling means comprise a pipe adapted to cool the combustion gas before entering the first analysis chamber.

  With these provisions, the cooling of the combustion gas is simplified. According to particular features, the device as briefly described above comprises means for adjusting the predetermined concentration value in the first analysis chamber.

  Thanks to these arrangements, it is possible to increase the sensitivity to detect the malfunctions of the combustion gas generator, for example a boiler, and to protect each sensor of the second analysis chamber as much as possible and / or to choose to reduce the sensitivity in order to minimize the risk of stopping the combustion gas generator, for example a boiler.

  According to particular features, the first sensor is an infrared ray sensor coupled to an infrared ray emitter, said beams passing through the first analysis chamber between the emitter and the sensor.

  Thanks to these provisions, the first sensor can not be damaged by the presence of a gas in the flue gas.

  According to particular characteristics, at least one second sensor of the second analysis chamber is an electrochemical sensor.

  With these provisions, the reliability and sensitivity of the concentration measurement in the second analysis chamber is improved.

  According to particular features, at least a second sensor of the second analysis chamber is adapted to provide a signal representative of the concentration of carbon dioxide.

  According to particular characteristics, at least one second sensor of the second analysis chamber is adapted to provide a signal representative of the concentration of carbon monoxide.

  According to particular characteristics, at least a second sensor of the second analysis chamber is adapted to provide a signal representative of the concentration of nitrogen dioxide.

  According to particular characteristics, at least a second sensor of the second analysis chamber is adapted to provide a signal representative of the oxygen concentration.

  According to particular features, the first sensor of the first analysis chamber is adapted to provide a signal representative of the concentration of carbon monoxide.

  Thanks to these provisions, each sensor of the second analysis chamber is protected against contamination by carbon monoxide.

  According to particular features, the device as briefly described above comprises two jacks operating in a synchronized manner, the first cylinder ensuring the sampling of combustion gases and the supply of each of the analysis chambers and the second cylinder ensuring the setting in motion of the first cylinder.

  Thanks to these provisions, the amount of gas supplied to each analysis chamber is constant, which increases the reliability of the measurements made. In addition, the complexity and cost of the device are reduced.

  According to particular features, the device as briefly described above comprises a compressed air purge circuit.

  Thanks to these provisions, the risks of contamination between successive samples are limited.

  According to particular features, the device as briefly described above comprises a temperature sensor adapted to measure the temperature of the combustion gases near the position of collection of the combustion gases by the flue gas sampling means.

  Thanks to these provisions, the influence of the temperature in a calculation of the efficiency of the combustion gas generator, for example a boiler, can be taken into account and compensated.

  According to particular features, the device as briefly described above comprises means for determining the efficiency of the combustion gas generator.

  Thanks to these arrangements, the efficiency of the gas generator can be known, including outside the periods of malfunction detected by the crossing of predetermined concentration thresholds, in order to better adjust this generator.

  According to particular features, the device as briefly described above comprises a heating means of the second analysis chamber.

  Thanks to these arrangements, the operation of the sensors of the second analysis chamber can be improved in favor of their sensitivity and the reliability of their measurements.

  According to particular features, the heating means is incorporated in an electronic control circuit of the components of said device. Thanks to these provisions, the complexity and the cost of the device are reduced.

  According to particular features, the device as briefly described above has a second sensor calibration means adapted to introduce ambient air into the second analysis chamber and to store the values of the signals supplied by the sensors of the second sensor. the second chamber of analysis.

  Thanks to these provisions, the aging of the sensors of the second analysis chamber is compensated.

  According to particular features, the device as briefly described above comprises a calibration means of the first sensor adapted to introduce ambient air into the first analysis chamber and to memorize the value of the signal supplied by the sensor. the first chamber of analysis.

  Thanks to these provisions, the aging of the sensor of the first analysis chamber or the fouling of the first analysis chamber are compensated.

  According to particular features, the device as briefly described above comprises a means for stopping the combustion gas generator when the crossing detection means of a predetermined value by the concentration of a gas in the first chamber detects said predetermined value is exceeded or when one of the signal values provided by a second sensor is greater than a predetermined value corresponding to said sensor.

  Thanks to these provisions, the risks of intoxication or pollution are reduced.

  According to particular features, the device as briefly described above comprises means for transmitting an alarm, remotely, when the stop means stops said generator.

  Thanks to these provisions, the person in charge of this generator can be immediately informed of the shutdown of the generator, for example a boiler.

  According to particular features, the device as briefly described above comprises means for cyclic tripping of the sampling and the analysis of combustion gases.

  Thanks to these provisions, the dangerous gas content of the combustion gases is automatically and regularly monitored.

  According to particular features, the device as briefly described above comprises a manual triggering means for sampling and analysis of combustion gases.

  With these provisions, the hazardous gas content of the combustion gases can be determined at any time, for example during maintenance operations, adjustment or repair of the generator.

  According to particular features, the device as briefly described above comprises means for displaying analysis results provided by said device.

  With these provisions, it is possible to know locally, at any time, the dangerous gas content in the combustion gases and, where appropriate, the efficiency of the combustion gas generator.

  According to a second aspect, the present invention provides a flue gas monitoring method, characterized in that it comprises: a flue gas sampling step for supplying a first gas analysis chamber; combustion; a step of measuring the concentration of at least one gas in the combustion gas present in the first analysis chamber; a step of detecting crossing of a predetermined value by said concentration and control of passage of the combustion gas from the first to a second analysis chamber if said predetermined value is not exceeded and a measurement step in the second chamber, by at least a second sensor, the concentration of at least one gas in the combustion gas present in the second chamber.

  The advantages, aims and special features of this process being similar to those of the device as succinctly described above, they are not recalled here.

  Other advantages, aims and features of the present invention will emerge from the description which follows, made for an explanatory and non-limiting purpose, with reference to the appended drawings, in which: FIG. 1 represents, schematically, a part of a first embodiment of the device object of the present invention, at rest, - Figure 2 shows, schematically, the same elements as Figure 1, during a sampling phase, - Figure 3 shows, schematically, the same elements as Figures 1 and 2, during a first phase of analysis, - Figure 4 shows schematically the same elements as Figures 1 to 3, during a cylinder emptying phase, - FIG. 5 represents, schematically, the same elements as FIGS. 1 to 4, during a filling phase of the second chamber; FIG. 6 represents, schematically, the same elements as FIGS. 1 to 5, in FIG. During a second analysis phase, FIG. 7 represents, schematically, the same elements as FIGS. 1 to 6, during a phase of ambient air suction, FIG. 8 represents, schematically, the same elements as FIGS. 1 to 7, during a chamber rinsing phase with ambient air, FIG. 9 schematically represents the same elements as FIGS. 1 to 8, during a first rinsing phase with compressed air, - Figure 10 shows, schematically, the same elements as Figures 1 to 9, during a second rinsing phase with compressed air, - Figure 11 shows, schematically, the same elements as FIGS. 1 to 10, during a phase of gas discharge for cylinder movement, FIG. 12 schematically represents the same elements as FIGS. 1 to 11, during a third phase of rinsing with compressed air and - Figure 13 shows schematically shows a device incorporating the part illustrated in FIGS. 1 to 12.

  FIGS. 1 to 12 show a first analysis chamber 100 provided with a sensor 105, a second analysis chamber 110 provided with four sensors 115A, 115B, 115C and 115D; a solenoid valve 120 connected to a gas sampling pipe 125 and a gas delivery pipe 130 ', on the one hand, and the first analysis chamber 100, on the other hand (according to variants, it is provided, or not, valves which prevent backflow into the sampling circuit and sampling in the discharge circuit), - a solenoid valve 135 connected to an ambient air sampling pipe 140, on the one hand, to a first cylinder 160 and to a solenoid valve 145, on the other hand and to the second chamber 110 and to a solenoid valve 155, on the other hand, a solenoid valve 145 connected to a compressor 150 (see FIG. 13) of ambient air, on the one hand, and first cylinder 160 and the solenoid valve 135, on the other hand, - the solenoid valve 155 of co mmunication chambers between them and with the first cylinder 160, - a second cylinder 165, - internal pipes 170 to 182 interconnecting the components indicated above and - a distributor "2-way 4 orifices" 185.

  According to the high or low position of the distributor 185, the compressed air by the compressor 150 enters, respectively, into the upper chamber of the cylinders 160 and 165, to lower them, or into the lower chamber of the jack 165 to raise the jack 165 and, thanks to its mechanical link with the cylinder 160, to raise the cylinder 160.

  The solenoid valves 135, 145 and 155 are controlled by an electronic circuit 190 illustrated in FIG. 13. The sensors 105 and 115 to 115D are connected to the electronic circuit 190.

  The first analysis chamber 100 is, for example, made of stainless steel. It has an internal volume substantially equal to the volume of gas displaced by the first cylinder 160. The sensor 105 is a carbon monoxide concentration sensor CO comprising an infrared ray emitter 106 and an infrared ray receiver 107, the optical path between the transmitter 106 and the receiver 107 passing through the first analysis chamber 100. For example, the transmitter and the receiver are diametrically opposed on the periphery of the first cylindrical analysis chamber 100.

  The second analysis chamber 110 is, for example, made of stainless steel. It has a volume substantially identical to that of the first analysis chamber 100. The four sensors 115A, 115B, 115C and 115D are electrochemical sensors, for example porous cells, respectively sensitive to the concentration of carbon monoxide CO, carbon dioxide CO2, nitrogen dioxide NO2 and oxygen 02.

  All sensors 115A to 115D, also called "cells" are mounted on a steel support ("setting mouth.) Each sensor only half returns to the second analysis chamber 110 sealed.

  The analysis chambers are made of stainless steel and have, for example, a thickness of 3 millimeters and a weight of 500 g. Thus, thanks to their thermal inertia, their internal temperature is not likely to be modified by the arrivals of combustion gases, which have been preliminarily cooled by the sampling pipe 125.

  The gas sampling pipe 125 is connected to a flue gas discharge pipe from a combustion gas generator 195, for example a boiler (see FIG. 13). The gas delivery pipe 130 is connected to the flue gas discharge pipe downstream of the gas sampling pipe 125.

  The ambient air taken by the ambient air sampling pipe 140 is taken near the combustion gas generator 195.

  The ambient air compressor 150 (see FIG. 13) is adapted to compress the ambient air to set the jacks 160 and 165 in motion and to flush the internal pipes and the analysis chambers 100 and 110.

  The first cylinder 160 and second cylinder 165 are mechanically connected in such a way that, when the second cylinder 165 is set in motion under the effect of the pressure of the compressed air, the first cylinder follows the same movement as the second cylinder. The second cylinder 165 is thus called "engine" since it sets the first cylinder 160 in motion and the first cylinder 160 is said to be "pump" since its function is to pump gases into the analysis chambers 100 and 110. that the cylinders 160 and 165 do not necessarily have the same internal volume.

  It is observed that, at rest, represented in FIG. 1, the solenoid valves 120 and 145 are closed, the solenoid valve 155 connects the first analysis chamber 100 to the solenoid valve 135 and the solenoid valve 135 connects it to the first jack 160. this rest configuration, the cylinders 160 and 165 are at the low end, near the pipes 174 and 172, respectively and the distributor 185 connects the compressor 150 to the upper parts of the cylinders 160 and 165.

  During a sampling phase illustrated in FIG. 2, the solenoid valve 120 is opened and, by changing the position of the distributor 185, the compressor 150 is connected to the lower part of the second cylinder 165 so as to raise the second cylinder 165 and, consequently, the first cylinder 160. The first cylinder 160 then sucks the gas contained in the first chamber 100 and this gas is replaced by a combustion gas removed, via the solenoid valve 120 and the sampling circuit 125.

  The operation of controlling the position of the cylinders by the position of the distributor 185 is not described later, being obvious to those skilled in the art. Only the changes in the positions of the cylinders are mentioned in the description below, the position of the distributor 185 being shown in FIGS. 1 to 12.

  Then the solenoid valve 120 is closed and, during a first analysis phase illustrated in FIG. 3, the combustion gases present in the first analysis chamber 100 are stabilized and, with the sensor 105, it is determined the concentration of at least one gas, here carbon monoxide CO, in the combustion gases.

  If this concentration is greater than a threshold value adjustable by the user, the combustion gas generator is stopped, for example a boiler illustrated in FIG. 13, and the user is warned by a remote communication, for example by a SMS message. (acronym for small message system for short message system). Indeed, in this case, a malfunction of the combustion gas generator is detected and its maintenance must be performed.

  In the case where the carbon monoxide CO concentration does not exceed the threshold value, the lower part of the first cylinder 160 is connected to the ambient air sampling circuit, via the solenoid valve 135 and, during a cylinder emptying phase illustrated in Figure 4, the cylinders 160 and 165 are lowered to empty the lower part of the first cylinder 16C).

  Then, the solenoid valve 120 is opened and the first analysis chamber 100 is connected to the second analysis chamber 110 via the solenoid valve 155 and the second analysis chamber 110 to the lower part. of the first cylinder 160, through the solenoid valve 135. During a filling phase of the second chamber illustrated in Figure 5, the cylinders 160 and 165 are raised in such a way that the contents of the first chamber Analysis 100 is sucked into the second analysis chamber 110.

  Then the solenoid valve 120 is closed and the lower part of the cylinder 160 is put into communication with the ambient air sampling circuit, via the solenoid valve 135. During a second analysis phase illustrated in FIG. Figure 6, we lower the cylinders 160 and 165 to discharge the contents of the first cylinder 160 in the ambient air sampling circuit.

  The stabilization of the combustion gases is then expected in the second analysis chamber 110 and, during an ambient air suction phase illustrated in FIG. 7, the cylinders 160 and 165 are raised to suck in air. ambient in the first cylinder 160. During this same phase, the sensors 115A to 115D provide measurements of concentration of different gases in the combustion gases present in the second analysis chamber 110.

  The solenoid valve 120 is then opened and the first analysis chamber 100 is connected to the second analysis chamber 110 via the solenoid valve 155 and the second analysis chamber 110 to the lower part of the chamber. first cylinder 160, through the solenoid valve 135. During a chamber rinsing phase illustrated in Figure 8, the cylinders 160 and 165 are lowered in such a way that: - the contents of the first cylinder 160, c that is, ambient air is discharged into the second analysis chamber 110 via the solenoid valve 135; the contents of the second analysis chamber 110 are forced back into the first chamber 100, through the solenoid valve 155 and - the contents of the first analysis chamber 100 is discharged into the discharge circuit 130, through the solenoid valve 120.

  Then, the solenoid valve 145 and the ambient air compressed by the compressor 150 are opened, purging the analysis chambers and the solenoid valves 120, 135 and 155, as illustrated in FIG. 9 (first rinsing phase with compressed air). .

  Then, via the solenoid valve 155, the first analysis chamber 100 is connected to the circuit 178 and the ambient air compressed by the compressor 150 purges the first analysis chamber 100 and the solenoid valves 120, 135 and 155, as illustrated in Figure 10 (second phase rinsing with compressed air).

  We then return to the rest configuration illustrated in FIG.

  In the case where, during the first analysis of the combustion gases carried out in the first analysis chamber, the concentration of carbon monoxide CO exceeds the adjustable threshold value, as illustrated in FIG. 11, the contents of the first chamber are emptied. 100, through the solenoid valve 120 and the discharge circuit 130, down the cylinders 160 and 165. Then, as shown in Figure 12, the solenoid valve 145 is opened and the first chamber is purged, some internal pipes and solenoid valves with compressed air by the compressor 150. Thus protects the sensors of the second analysis chamber 110 against contamination by carbon monoxide CO present in excess in the flue gas.

  We then return to the rest configuration illustrated in FIG.

  It is observed that the length of the flue gas collection pipe 125 is chosen so that the flue gases arrive in the first analysis chamber at a temperature close to ambient temperature. This piping can thus measure ten to thirty meters, according to the thermal characteristics of the sampling pipe 125.

  The second analysis chamber 110 is conditioned by the heating generated by the electronic circuit 190 illustrated in FIG. 13, at a temperature slightly higher than the ambient temperature in order to improve the quality of the measurements made by the electrochemical sensors 115A to 115D. and, in particular, by the sensor 1158 sensitive to the concentration of CO2 carbon dioxide.

  The analysis carried out in the first analysis chamber 100 makes it possible to evaluate the quality of the combustion gases in terms of their opacity to infrared rays and their content of impurities (solids, for example).

  Thanks to the implementation of two analysis chambers, the first of which makes it possible to decide whether the combustion gases can enter the second, there is no need for a filter. Indeed, if the combustion gases have a poor quality, they are rejected without passing into the second analysis chamber 110. Because the combustion gases are not filtered before entering the second analysis chamber 110 , in case their quality is sufficient, the measurements made by the sensors 115A to 115D are very faithful. Indeed, no obstacle modifies the contents of the combustion gases before their arrival in the second analysis chamber 110.

  The threshold value used at the end of the first analysis, to determine whether the combustion gases can enter the second analysis chamber 110, is adjustable or programmable between a minimum value and a maximum value corresponding to the regulations in force.

  For example, the maximum threshold value corresponds to the value 0.5 of the Brigon scale and the minimum threshold value corresponds to 0.1 on this scale. It is recalled that the Brigon scale measures the opacity by means of a pump (actuated three times) and a blotter, the trace on the blotter being compared with the calibration traces to give a value between 0 and 12 In the present case, 0.5 of the Brigon scale corresponds to about 1500 ppm.

  It is observed that waiting phases allow the stabilization of the gases in the analysis chambers. For example, the waiting time is five seconds in the first room and forty five seconds in the second room. Each measured concentration value is transmitted and stored in the memory of the electronic circuit 190 illustrated in FIG. 13.

  Among the advantages of the present invention, it is observed that, since the quantity of gas pumped is always constant, the temperature of the gases is controlled and the accuracy of the measurements is increased.

  In an automatic operating mode, the sequence illustrated in FIGS. 1 to 12 is carried out every six hours, except for manual triggering, for example during the maintenance, maintenance or adjustment phases of the combustion gas generator.

  The rinsing cycle with compressed air lasts, for example, fifteen seconds.

  FIG. 13 shows the combustion gas generator 195, the solenoid valves 120, 135, 145 and 155, the sensors 105 and 115A to 115D, the distributor 185, the electronic circuit 190 in a sealed housing 200 also containing the chambers 100 and 110. The electronic circuit 190 comprises a processor 205, a memory 210, a modem 215, a power supply 220, a touch screen 225, an input 230 of a combustion gas temperature probe 235, 240 input of a room temperature sensor 245 and other electronic components (not shown). The conductive tracks of the electronic circuit 190, which interconnect the various components shown and the different signal inputs and outputs, are not shown in FIG. 3, for the sake of clarity of this figure.

  The combustion gas generator 195 is, for example, a gas or oil boiler.

  The solenoid valves 120, 135, 145 and 155 and the distributor 185 are controlled by the electronic circuit 190 to carry out the cycle illustrated in FIGS. 1 to 12. It can be seen that the sampling circuit 125 draws combustion gases in an evacuation duct. 250, for example a chimney, of the generator 195 and that the combustion gas discharge circuit 130 opens into the exhaust duct 250, downstream of the inlet of the sampling circuit 125.

  The signals from the sensors 105 and 115A to 115D are received by the electronic circuit 190 to determine whether the combustion gases can enter the second analysis chamber 110, depending on the signals provided by the sensor 105 and to determine the concentrations of the gas in the combustion gases, depending on the signals provided by the sensors 115A to 115D. The electronic circuit 190 also performs a calibration of the sensors and determines the efficiency of the combustion gas generator, according to the signals provided by the sensors 115A and 115D and signals from the temperature probes 235 and 245.

  The housing 200 is sealed to maintain the second analysis chamber 110, which it contains, at a temperature slightly above room temperature, which is favorable for the detection of gas concentrations by the sensors 115A to 115D.

  The processor 205 controls the operation of each of the system components and reads the values of the signals provided by the sensors. The memory 210 contains the operating program of the processor 205 and the archived data, in particular the gas concentrations, the alarms, the malfunctions of the combustion gas generator and the yields of this generator.

  The modem 215 is adapted to emit, remotely, alert messages and, optionally, results of processing, concentrations and efficiency, performed by the processor 205. The alert messages can be transmitted as SMS short messages. Preferably, the rnodem 215 is a modem that transmits wireless communications. The power supply 220 supplies the electronic circuit 190. The touch screen 225 allows the user to communicate with the processor 205, to obtain processing results and / or raw data and to control its operation, for example its restarting or manually triggering a flue gas analysis cycle.

  The flue gas temperature probe 235 is placed near the inlet of the sampling circuit 125 to provide the temperature of the withdrawn gases.

  The ambient temperature sensor 245 is, on the contrary, remote from the combustion gas generator, to provide the temperature of the ambient air entering the combustion gas generator.

  To determine the efficiency, the two temperatures measured by the temperature probes 135 and 145 are introduced in the calculation of the yield. For example, to determine a combustion (boiler) efficiency, the ambient temperature is subtracted from the smoke temperature. For example, if the flue gas temperature is 200 C and the ambient temperature is 20 C, the 180 C value for the flue gas temperature is used in the yield calculation. The concentration of carbon dioxide CO2 is also particularly important in the calculation of yield.

  The processor 195 performs the calibration of the sensors automatically to compensate for the drift of their responses. For this purpose, the processor controls a reading of the sensors for the ambient air, knowing that it must contain 20.9% oxygen 02, and 0% carbon dioxide CO2, 0% carbon monoxide CO and 0% nitrogen dioxide NO2.

  Preferably, a measurement is made in the first analysis chamber 100 just before the arrival of combustion gas.

  It is observed that the number of analyzes performed by sensors in the first or second chamber is not limited to the numbers of one and four indicated in the embodiment illustrated in FIGS. 1 to 12, but may be extended to any desired number.

Claims (16)

  1 - Combustion gas monitoring device, characterized in that it comprises: - means for sampling (120 to 165) of combustion gas adapted to supply a first combustion gas analysis chamber (100); - A first analysis chamber provided with a first sensor (105) adapted to provide a signal representative of the concentration of at least one gas in the combustion gas present in the first analysis chamber; a detection means (190) for passing a predetermined value by said concentration adapted to control the passage of the combustion gas from the first to a second analysis chamber if said predetermined value is not exceeded and - the second analysis chamber (110) provided with at least one second sensor (115A to 115D) adapted to provide a signal representative of the concentration of at least one gas in the combustion gas present in the second chamber.   2 - Device according to claim 1, characterized in that the sampling means (120 to 165) are adapted to cool the combustion gas before entering the first analysis chamber (100).   3 - Device according to any one of claims 1 to 2, characterized in that it comprises a means (190) for adjusting the predetermined concentration value in the first analysis chamber.   4 - Device according to any one of claims 1 to 3, characterized in that the first sensor (105) is an infrared ray sensor coupled to an infrared ray emitter, said beams passing through the first analysis chamber (100) between the transmitter and the sensor.   - Device according to any one of claims 1 to 4, characterized in that at least a second sensor (115A to 115D) of the second analysis chamber (110) is an electrochemical sensor.   6 - Device according to any one of claims 1 to 5, characterized in that the first sensor (105) of the first analysis chamber (100) is adapted to provide a signal representative of the carbon monoxide concentration.   7 - Device according to any one of claims 1 to 6, characterized in that it comprises two cylinders (160, 165) operating in a synchronized manner, the first cylinder (160) providing the collection of combustion gas and the supply each of the analysis chambers (100, 110) and the second cylinder (165) ensuring the movement of the first cylinder.   8 - Device according to any one of claims 1 to 7, characterized in that it comprises a compressed air purge circuit (120 to 155).   9 - Device according to any one of claims 1 to 8, characterized in that it comprises a temperature sensor (235) adapted to measure the temperature of the combustion gases near the position of collection of the combustion gases by the combustion gas sampling means (125).   - Device according to any one of claims 1 to 9, characterized in that it comprises a means for determining the efficiency (190) of the combustion gas generator.   11 - Device according to any one of claims 1 to 15, characterized in that it comprises a heating means (190, 200) of the second analysis chamber.   12 - Device according to claim 11, characterized in that the heating means (190, 200) is incorporated in an electronic control circuit of the components of said device.   13 - Device according to any one of claims 1 to 12, characterized in that it comprises a calibration means of at least one sensor (105, 115A to 115D) adapted to introduce ambient air into the chamber analyzing said sensor and memorizing the values of the signals provided by said sensor.   14 - Device according to any one of claims 1 to 13, characterized in that it comprises a stop means (190) of the combustion gas generator when the crossing detection means of a predetermined value (190) by the concentration of a gas in the first chamber (100) detects that said predetermined value is exceeded or when one of the signal values provided by a second sensor (115A to 115D) is greater than a predetermined value corresponding to said sensor.   - Device according to claim 14, characterized in that it comprises means for transmitting (190, 215) an alarm, remotely, when the stop means stops said generator.   16 - Device according to any one of claims 1 to 15, characterized in that it comprises a means (190) for triggering cyclic sampling and analysis of combustion gas.   17 - Device according to any one of claims 1 to 16, characterized in that it comprises a triggering means (190, 225) manual sampling and analysis of combustion gas.   18 - Device according to any one of claims 1 to 17, characterized in that it comprises a display means (225) of analysis results provided by said device.   19 - Process for monitoring flue gas, characterized in that it comprises: - a flue gas sampling step for supplying a first analysis chamber (100) with flue gas; a step of measuring the concentration of at least one gas in the combustion gas present in the first analysis chamber; a step of detecting a crossing of a predetermined value by said concentration and control of the passage of the combustion gas from the first to a second analysis chamber (110) only if said predetermined value is not exceeded and - a measurement step, in the second chamber, by at least a second sensor (115A to 115D), the concentration of at least one gas in the combustion gas present in the second chamber.