Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/02—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/34—Burners specially adapted for use with means for pressurising the gaseous fuel or the combustion air
  • F23D14/36—Burners specially adapted for use with means for pressurising the gaseous fuel or the combustion air in which the compressor and burner form a single unit
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/46—Details
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/46—Details
  • F23D14/48—Nozzles
  • F23D14/58—Nozzles characterised by the shape or arrangement of the outlet or outlets from the nozzle, e.g. of annular configuration
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/46—Details
  • F23D14/72—Safety devices, e.g. operative in case of failure of gas supply
  • F23D14/725—Protection against flame failure by using flame detection devices
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/46—Details
  • F23D14/72—Safety devices, e.g. operative in case of failure of gas supply
  • F23D14/74—Preventing flame lift-off
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/46—Details
  • F23D14/72—Safety devices, e.g. operative in case of failure of gas supply
  • F23D14/82—Preventing flashback or blowback
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
  • F23G5/50—Control or safety arrangements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
  • F23L1/00—Passages or apertures for delivering primary air for combustion 
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
  • F23L17/00—Inducing draught; Tops for chimneys or ventilating shafts; Terminals for flues
  • F23L17/005—Inducing draught; Tops for chimneys or ventilating shafts; Terminals for flues using fans
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23N—REGULATING OR CONTROLLING COMBUSTION
  • F23N5/00—Systems for controlling combustion
  • F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
  • F23N5/10—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using thermocouples
  • F23N5/102—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using thermocouples using electronic means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23N—REGULATING OR CONTROLLING COMBUSTION
  • F23N5/00—Systems for controlling combustion
  • F23N5/24—Preventing development of abnormal or undesired conditions, i.e. safety arrangements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23N—REGULATING OR CONTROLLING COMBUSTION
  • F23N5/00—Systems for controlling combustion
  • F23N5/24—Preventing development of abnormal or undesired conditions, i.e. safety arrangements
  • F23N5/242—Preventing development of abnormal or undesired conditions, i.e. safety arrangements using electronic means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
  • F23C2900/00—Special features of, or arrangements for combustion apparatus using fluid fuels or solid fuels suspended in air; Combustion processes therefor
  • F23C2900/9901—Combustion process using hydrogen, hydrogen peroxide water or brown gas as fuel
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2209/00—Safety arrangements
  • F23D2209/10—Flame flashback
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2209/00—Safety arrangements
  • F23D2209/20—Flame lift-off / stability
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
  • F23D2900/14—Special features of gas burners
  • F23D2900/14641—Special features of gas burners with gas distribution manifolds or bars provided with a plurality of nozzles
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23N—REGULATING OR CONTROLLING COMBUSTION
  • F23N2225/00—Measuring
  • F23N2225/08—Measuring temperature
  • F23N2225/20—Measuring temperature entrant temperature
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23N—REGULATING OR CONTROLLING COMBUSTION
  • F23N2231/00—Fail safe
  • F23N2231/28—Fail safe preventing flash-back or blow-back
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23N—REGULATING OR CONTROLLING COMBUSTION
  • F23N2233/00—Ventilators
  • F23N2233/06—Ventilators at the air intake
  • F23N2233/08—Ventilators at the air intake with variable speed

Definitions

• the present invention relates to a flashback-proof gas burner adapted to be coupled to an aperture of a combustion chamber.
• the gas burner is characterized by a specific configuration of a probe and its location for sensing the temperature.
• the probe has a fast response to changes in temperature, in particular when the flame is extinguished, allowing a fast response to close a valve for supplying gas to the inlet port, thereby preventing any explosion.
• the combustion of hydrocarbons formed by mixtures of various gases has conditions that differ from the combustion of gases such as hydrogen, methane or propane.
• gases such as hydrogen, methane or propane.
• Each of the gases has different chemical kinetics with very different reaction velocities and combustion temperatures.
• a different velocity of reaction means that the flame position in a burner tends to be closer to the nozzles or further away, so the burner designs must be suitable for stable and safe flame anchoring.
• premix burners have several problems related to safety. The most obvious one is that once the fuel is mixed with the comburent the reaction can start any time an ignition energy is reached and this condition could happen before reaching the introduction of the mixture into the combustion chamber. If this happens an explosion occurs with the danger of such an accident.
• the accumulation of fuel and comburent without the fuel being burned is a source of explosion risk. This condition occurs mainly when the burner is operating and for any reason there is a flame extinction.
• the fuel or fuel and comburent mixture continues to be entering into the combustion chamber without combustion that exhausts the fuel so very high storage volumes of fuel and comburent can be reached which can explode causing serious damage.
• a first aspect of the invention is a flashback-proof gas burner.
• the flashback-proof gas burner is adapted to be coupled to an aperture of a combustion chamber such that the combination of the burner and the combustion chamber is a heat generating system.
• the first aspect of the invention is a burner that allows a rapid response to flame extinction.
• the first aspect of the invention is suitable and, more specifically, adapted to be installed in an opening of a combustion chamber, allowing it to serve, for example, as a part of a replacement kit for other burners installed on the opening of the combustion chamber, replacing different combustion mechanisms or burners adapted to burn different gases. In this configuration it is not necessary to make any changes to the combustion chamber.
• the gas burner is suitable for the combustion of a fuel gas comprising hydrogen, more specifically adapted for the combustion of hydrogen.
• the gas burner is a flashback-proof gas burner, where the junction between fuel and comburent occurs just a short time before combustion takes place. This configuration is very safe since the fuel does not have the ability to react until it is already introduced into the combustion chamber.
• the fuel is fed through one set of conduits and the comburent is fed separately through a different set of conduits than the fuel.
• the fuel inlet port allows fuel to enter the combustion chamber, e.g., from a pressure pump or from a tank containing the fuel at a pressure above the pressure at which the combustion chamber is in operation, preferably about the ambient pressure.
• the fuel gas manifold receives the fuel coming from the inlet port and serves as a space where the fluidic conditions of the fuel are homogenized, for example the pressure, so that it is the same at any location and, in particular where the at least one fuel gas nozzle is located. If according to an embodiment the fuel gas manifold comprises a plurality of fuel gas nozzles, each nozzle operates approximately at the same conditions.
• the air inlet port allows air to enter the combustion chamber, e.g. from an air impeller, thereby providing control of the flow, in particular the air/fuel rate when the flow of the fuel gas is also under control as it is in our case.
• the air/fuel rate is in an operative manner with respect to the air/fuel rate at stochiometric conditions in the range [1.05, 2.1], and more preferably in the range [1.0, 1.8], and more preferably in the range [1.1, 1.7], and more preferably in the range [1.2, 1.6], and more preferably in the range [1.3. 1.5], and more preferably about 1.4, in all cases operating with excess of oxygen, measurements in volume.
• the system formed by the combustion chamber and the burner includes an exhaust probe at the exhaust gas outlet to measure at least one component concentration of exhaust gas.
• This probe is part, preferably, of a closed loop control system to ensure the air/fuel ratio as a setpoint value.
• the air/fuel ratio is constant for any air intake flow rate.
• the air manifold comprises at least one air outlet wherein the at least one fuel gas nozzle injects fuel into the combustion chamber passing through the air outlet.
• the fuel gas exits the gas nozzle passing through the air outlet allowing a flow of air to impinge on the injected fuel gas causing the two flows to meet in the combustion chamber.
• the fuel gas manifold comprises a plurality of fuel gas nozzles injecting fuel gas through the at least one air outlet of the air manifold.
• the air manifold comprises a plurality of air outlets and each fuel gas nozzle is adapted to inject fuel gas through an air outlet of the air manifold.
• the probe is the element responsible for carrying out a thermal measurement of a thermal condition where this probe comprises at least two distinct parts, a region where a parameter representative of a thermal condition is measured and, a connecting portion that establishes a link between the region where the measurement is carried out and the connections that provide the signal with the measurement allowing to act for example at the moment when a flame extinction is detected.
• the connecting portion is a structural part although it may have other functions such as that of transporting the signal obtained in the measurement region.
• the connecting portion is interpreted as a part of the probe other than the measurement area.
• An example of a connecting portion is the body of the probe with wires or communication elements for carrying the measurement signal.
• Another example of connecting portion is a part of the head body, wherein the head comprises the measurement region and a distinct part which is cooled according to the invention and is different from the measurement region.
• the connecting portion does not have to be a complete part or piece, but only a portion that, in operative manner, is under different temperature conditions than the measurement region of the probe.
• the measurement region is located in, or close to, a region where the flame is operationally located during combustion. This allows the flame temperature, an estimate of the flame temperature, or a parameter representative of a thermal condition to be measured.
• An example of a parameter representative of a thermal condition is a probe that provides an electrical potential difference in response to a temperature or a temperature variation. Any physical element of the probe that supports the measurement region will also be at an elevated temperature. This causes a thermal inertia which means that sudden temperature changes such as that caused by flame extinction are not detected in the signal provided by the temperature measurement region instantaneously but require a period of time which may be too long for safety requirements. A very slow response of the signal with the temperature value of the measuring region prevents the fuel feed valve from being closed in time.
• the connecting portion of the probe is housed in the air manifold.
• the interior of the air manifold contains fresh air since it has not yet been met even with the fuel.
• the flow of fresh air, in this configuration is in direct contact with the connecting portion of the probe by convention, a very effective form of heat transport, which allows its temperature to tend to drop as rapidly as possible.
• the temperature measurement region upon flame extinction, the temperature measurement region, being attached to the cooled connecting portion, reduces its temperature by conduction, giving a response in the probe output signal that shows the actual temperature drop with a much faster response time.
• the probe is a thermocouple.
• thermocouple is a device that makes use of two dissimilar metals in such a way that depending on the temperature in one and the other metal a potential difference is established.
• the dissimilar metals are close together so that the potential difference occurs at the junction. This is not the only configuration but the metals can be at different points under different thermal conditions.
• thermocouples In the context of the invention two types of thermocouples will be differentiated, a first type of thermocouple where the measurement occurs in a measurement region located at the tip of the probe and where the response in the form of potential difference is representative of the absolute temperature at which the tip is located.
• thermocouple of lower cost, has a first metal in the region of measurement, in the tip of the probe, and a second metal in a reference point that we will call cold point, distant from the region of measurement and, that is located in the connecting portion.
• the measured value does not establish the absolute temperature measurement value, it provides a signal representative of the thermal conditions near the flame that depends, among other factors, on the temperature difference between the measurement region and the cold point.
• the probe is a thermocouple, the temperature measurement region of the probe being at the bimetallic joint of the thermocouple and, the connecting portion of the probe being at least a part of metallic connections connecting the bimetallic joint of the thermocouple.
• thermocouple This embodiment is according to the first type of thermocouple.
• thermocouple is a probe comprising a bimetallic joint adapted to provide a signal responsive to the temperature.
• the signal is a potential difference of greater or lesser magnitude depending on the temperature of the bimetallic joint.
• the signal is transmitted to a connection through electrically conductive elements. These electrically conductive elements are also good heat conducting elements and are part of the connecting portion so that in operating mode it is subjected to the burner supply air flow.
• the bimetallic joint is at a temperature close to the flame temperature when the burner is in operating mode.
• the burner feed air is cold and in contact with the connecting portion which is also cold, closer to ambient temperature than the measurement region, so that as soon as flame extinction occurs the temperature of the connecting portion causes rapid cooling of the bimetallic joint through the conductive elements that keep the bimetallic joint and the connecting portion connected.
• thermocouple comprising two dissimilar metal parts, and wherein the measurement region of the probe comprises one dissimilar metal and, the other dissimilar metal is at a reference cold point located in the connecting portion of the probe wherein the probe is adapted to provide a signal amplitude at least responsive to the temperature difference between the temperature of the two dissimilar metals.
• the signal amplitude is responsive to the temperature difference between two parts of the probe, the measurement region, which is operatively located near or in the flame, and the cold point, which is operatively located in the connecting portion and is cooled by the fresh air flowing inside the air manifold.
• the temperature of the measurement region is cooled down and the temperature of the cold point is also cooled down. Since the cold point is refrigerated by the fresh air flowing within the air manifold where it is located, the temperature difference is increased at a first stage and tends to be zero as time goes on.
• Flame extinction can be detected in several ways. According to a first criterion, because the variation of the signal being proportional to the temperature difference, in absolute value, exceeds a predetermined threshold.
• Threshold values are positive values and are lower the smaller the variation allowed.
• the values are positive because variation relative to a reference is measured using the absolute value function, which is always positive.
• the same criterion can be transformed into one that uses absolute (or real) values instead of values relative to a given reference.
• the comparison is not with a threshold value, but with values that are either above or below the reference value.
• this alternative form of expression is considered equivalent in all cases.
• the derivative with respect to time of the signal being proportional to the temperature difference, or an estimate of such a derivative, varies in absolute value beyond a predetermined threshold.
• the probe has an elongated shape, the temperature measurement region being located at one end of the probe.
• the elongated configuration of the probe allows the installation of the probe positioned in two different orientations:
• thermocouple in particular to the first type of thermocouple and to the second type of thermocouple.
• the air manifold houses the fuel gas manifold wherein, the air manifold has a flat or convex wall. It is this flat or convex wall where the air openings are located through which the fuel gas is introduced by the use of the nozzles or injectors (both terms will be used).
• the fuel gas manifold housed inside the air manifold, locates the nozzles close to the internal area of the flat or convex wall of the air manifold.
• this fuel gas manifold is formed by at least two pieces, preferably in stamped sheet metal, which are joined together. These two pieces extend along a main reference surface which is either flat or convex.
• the fuel gas manifold according to one example, has openings and does not cover the entire main reference surface. The probe preferably passes through one of these openings and the perpendicular or inclined direction is with respect to this main reference surface.
• the first option is optimal for the first type of thermocouple wherein the measurement region is under the influence of the air flow
• the second option is optimal for the second type of thermocouple, where the measurement region is out of the influence of the air flow.
• the fuel gas manifold is housed within the air manifold.
• a configuration in which the fuel gas manifold is housed inside the air manifold is a very effective configuration for locating the at least one fuel gas nozzle or injector on a side of the wall of the air manifold defining a boundary between its interior and the combustion chamber.
• the fuel gas manifold comprises a plurality of injectors or nozzles, these are distributed on a surface of the fuel gas manifold close to the inner surface of the wall of the air manifold.
• injectors or nozzles these are distributed on a surface of the fuel gas manifold close to the inner surface of the wall of the air manifold.
• the at least one fuel gas nozzle injects the fuel gas through the at least one air outlet, and wherein there is a clearance between the fuel gas nozzle and the air outlet to allow the passage of the air.
• the air outlet through which the fuel gas is injected by means of a nozzle or injector has a clearance between the outlet and the nozzle.
• the clearance is shown according to the radial direction taking the axis of the nozzle as a reference.
• air ducts are provided between an inner wall of the air manifold wall and the fuel gas manifold wall. These ducts promote air distribution near each nozzle. These air ducts are also reinforcing ribs for the surface of the air manifold located facing the combustion chamber.
• This clearance allows air to enter the combustion chamber but causes it to flow against the fuel gas flow, preferably in a direction transverse to the gas flow, which promotes junction between the two.
• the fuel gas manifold comprises at least two plates joined configuring either a flat collector or a collector that extends along a convex surface.
• a very efficient combustion mode is one in which the flame has a flat configuration or at least extends along a surface.
• the joining process of the air and fuel gas takes place on one side of the surface feeding the flame and after combustion the hot gases carry the heat to the rest of the combustion chamber where there are exchange means to transport the heat to the final application site.
• the air manifold comprises a wall with the air outlets being either a flat wall or a wall that extends along a convex surface.
• the wall of the air manifold with the air outlets defines, among other parameters, the shape and anchorage of the flame.
• a flat wall or a wall extending along a convex surface allows to optimize the available surface of the burner when installed in the opening of the combustion chamber.
• the flat wall or a wall extending along a convex surface is hosted within an area surrounded by the seat adapted to close the aperture of the combustion chamber when in operative manner the burner is installed in the combustion chamber.
• the probe passes through at least the wall of the air manifold comprising the air outlets.
• the probe is partially located in the interior of the air manifold and the end with the region for temperature measurement is located in the space of the combustion chamber. According to this embodiment, the probe passes through at least the wall of the air manifold that contains the air outlets.
• This arrangement has the advantage of giving rise to a very compact and reactive device and is particularly useful when the configuration of the area where the nozzles are distributed has a configuration extending according to a plane or according to a convex surface since a position perpendicular or close to perpendicular to this surface allows a very fast cooling effect.
• the probe passes through the fuel manifold.
• the configuration described for the fuel manifold is either flat or convex. This does not mean that the entire manifold covers an area of either flat or convex configuration but rather that it positions the nozzles according to either a flat or convex spatial distribution. That is, according to an embodiment the fuel manifold is formed by conduits for example radially distributed covering the area where the nozzles are positioned.
• the characteristic that the probe "passes through” the fuel manifold admits two interpretations, either that it passes from one side to the other taking advantage for example of the gaps or openings left by the radial ducts, or that it actually passes through the walls of the fuel gas where, in this case, it would be necessary to seal the inlet and outlet openings in the fuel manifold and to thermally insulate the section of the probe housed inside the fuel manifold.
• the first case is the preferred one.
• the probe passes through the fuel manifold, preferably passing through openings, and also through at least one wall of the air manifold, preferably through an opening.
• the burner further comprises a processor
• Option a) is preferably used when the probe is a thermocouple of the first type when the measurement responsive to the temperature is the temperature value at the measurement region of the probe and, option b) is preferably used when the probe is a thermocouple of the second type when the measurement responsive to the temperature is a measurement of the temperature difference between the measurement region and the cold region of the probe.
• the burner is provided with safety means that allow to react to a dangerous situation, such as the extinction of the flame.
• the signal generated by the probe is transmitted to a processor which compares the value of the signal, which is representative of the temperature in the temperature measurement region, with a threshold value. If the signal representative of the temperature falls below this threshold, the processor sends a signal that commands the closure of a fuel supply valve to the burner.
• the closing time is not instantaneous, but the configuration according to one of the examples described allows a very fast response when causing a signal generation, the signal indicating the temperature changes due to the low thermal inertia.
• the processor responds to this change in the input signal by closing the valve in a very short time, demonstrably less than the second required by the regulations.
• the processor is further adapted to send a signal to the commended valve to shut off the flow fuel gas inlet if the signal that is representative of temperature is higher than a second threshold value.
• the processor is adapted to react by closing the fuel gas flow inlet when it detects a flame extinction and also when there are combustion conditions that result in a very high temperature that exceeds a predetermined condition. This is also a dangerous condition that must be controlled and, according to this embodiment, the processor also responds by closing the commanded valve.
• a second aspect of the invention is a burner system comprising a burner according to any of the previously disclosed embodiments and, further comprising a combustion chamber, the burner installed and adapted to be coupled to an aperture of a combustion chamber.
• the burner may further comprise two probes to have a redundant measure, being possible to have both thermocouples of one type, both of the second type or a first probe of one type and the second probe of the second type.
• aspects of the present invention may be embodied a burner flashback-proof gas burner adapted to be coupled to an aperture.
• FIG. 1 shows an embodiment of the flashback-proof gas burner (B) including a combustion chamber (5).
• the combustion chamber (5) is a chamber where the combustion reaction takes place in the form of a flame. In this combustion reaction heat is generated which is transferred for example via a heat exchanger to the destination of this energy depending on the end application.
• the combustion chamber (5) has an aperture (5.1) over which the burner (B) is coupled and fixed.
• This configuration allows not only the maintenance of both the burner(B) and also of the elements accessible from inside the combustion chamber (5) but also allows for example the replacement of the complete burner (B). This replacement may be justified by the need to use a burner (B) configured for a different type of fuel.
• the burner (B) is configured to burn a gas fuel comprising hydrogen and more specifically only hydrogen.
• the burner(B) of this embodiment is a flashback-proof gas burner and therefore has an air inlet port (1), the comburent, and a gas fuel inlet port (2).
• Figure 1 shows at the lower part of the figure air impulsion means (4) for to draw air from the atmosphere into the combustion chamber (5) imposing an overpressure above atmospheric pressure. The air leaving the impulsion means (4) is conducted through an air conduct (6.1) to the interior of an air manifold (6).
• a commanded valve (8) is also shown in the lower part of figure 1 , which controls the flow of fuel gas.
• the fuel gas comes either from a source under pressure or by means of an impulsion of the fuel gas. This source of the fuel gas is not shown in the figure in the sake of clarity.
• Figure 2 is a perspective view of the same embodiment where the burner (B) is held together with the commanded valve (8) and the air impulsion means (4) and, in turn, this group of elements is separated from the combustion chamber (5) to allow observing the aperture (5.1) of the combustion chamber (5) on which the burner (B) is engaged.
• the flame formation in the burner (B) occurs just behind the circular plate that engages over the aperture (5.1) of the combustion chamber (5) also of circular configuration according to this specific embodiment.
• the flame has a configuration also mainly flat and projects the heat into the combustion chamber (5) which in this embodiment comprises a heat exchanger (5.2) shown through the aperture (5.1) as a ring stack.
• Figure 4 shows the same burner (B) after having removed the combustion chamber (5).
• Figures 1 to 4 also show the outer part of two probes (7), mainly the end allowing the connection that receives the signal measured by the probe (7) and that allows to determine a measurement of the flame temperature or of a zone close to the flame.
• the use of two probes (7) is a safety measure for redundancy in the measurement of the same parameter.
• the commanded valve (8) allows the burner (B) to be shut off, for example, because it receives a signal from the processor in response to flame extinction event.
• the fuel gas is led from the commanded valve (8) to a fuel gas manifold (3) by means of a fuel gas conduct (3.1).
• the burner (B) is a flashback-proof gas burner so that the fuel gas and the comburent are meet just at the moment of entering into the combustion chamber (5) and also in cross flow.
• the fuel gas manifold (3) is housed inside the air manifold (6) and both (3, 6) have a similar configuration.
• the fuel gas manifold (3) has a flat configuration, at least of the surface on which there is distributed a plurality of fuel gas nozzles (3.2) for providing the injection of fuel gas jets inside the combustion chamber (5).
• Figure 5 shows a perspective view of the burner (B) with the point of view located on the other side of the burner with respect to the point of view used in figures 1 to 4 .
• This view shows a heat insulator (10) which located within the aperture (5.1) of the combustion chamber (5) ensuring a thermally protected closure.
• This figure also shows the electrode (9) that cause the flame ignition, placing their end in a position close to the region where, in an operative way, the flame is anchored to the burner.
• outlets which correspond to the outlet openings of the plurality of fuel gas nozzles (3.2) destined to introduce the fuel gas inside the combustion chamber (5).
• These outlets are air outlets (6.2), i.e., they are the outlets through which the air exits since the ends of the fuel gas nozzles (3.2) do not completely close the surrounding air outlets (6.2).
• the air outlets (6.2) are outlets located at a wall of the air manifold (6).
• the fuel gas manifold (3) and the air manifold (6) have a flat configuration because the location of the fuel gas nozzles (3.2) must be close to and inside in the air outlets (6.2) located in a wall of the air manifold (6).
• Figure 6 shows a sectional view of the example shown in figure 5 where the flat configuration of the fuel gas manifold (3) is observed and how it is housed inside the air manifold (6) where one of its walls is approximately flat, the wall where the air outlets (6.2) are located.
• the wall of the air manifold (6.2) that is close and parallel to a wall of the fuel gas manifold (3) has reinforcing ribs that also generate channels that facilitate the entry of air into the area surrounding the air outlets (6.2) to reduce pressure drop.
• Figure 7 shows another sectional view where the probe (7) is shown in an exploded perspective. This same view is seen in Figure 9 where the probe (7) is now in its final position. The sectioned view has removed half of the burner (B) where a second probe (7) is located.
• Figure 8 is an enlargement of Figure 9 and shows how the probe (7) is positioned in relation to each of the internal spaces of the burner (B), in particular the air manifold (6) and the fuel gas manifold (3).
• the probe (7) For extracting the measured signal, the probe (7) has, one connection located at the measurement region (7.2) and a second connection, the cold point, at the connecting region.
• the signal is responsive to the potential difference between the two points.
• the probe (7) is a second type thermocouple in which the signal is generated in the form of a potential difference in response to a certain temperature conditions at the measurement region (7.2) and at the cold point.
• a sleeve-shaped section that allows the threading on the rear wall of the air manifold (6) establishing a sealed joint and, also an elongated section, which in this embodiment is metallic, where the signal is transmitted.
• This extension which in this embodiment is metallic comprises good conductors for heat and, the parts that conduct the signal are also good signal conductors.
• connecting portion (7.1) to any intermediate section between the two ends of the probe (7) having thermal conduction ability with the temperature measuring region (7.2).
• the connecting portion (7.1) also has the cold point of the thermocouple.
• the connecting portion (7.1) is located inside the space formed by the air manifold (6) so that this connecting portion (7.1) will be subjected to heat transfer phenomena by convection upon interaction with the air circulating inside the air manifold (6).
• the temperature of the connecting portion (7.1) is close to the ambient temperature except for the changes that may be produced by the pressure rise of the air impulsion means (4).
• the temperature measuring region (7.2) is at one end wherein the probe (7) passes through at least the wall of the air manifold (6), and then the temperature measuring region (7.2) is in direct contact with the interior of the combustion chamber (5).
• the probe (7) also overcomes the position of the fuel gas manifold (3) either by passing through it or, more safely, by passing between channels or ribs that carry the fuel gas leaving free spaces or openings between such channels or ribs such as the one that allows the passage of the probe (7).
• This form of passage without passing through the interior of the fuel gas manifold (3) makes it possible not to transmit high temperature to the interior of a space which in operational form contains the fuel gas reducing risks.
• the temperature measuring region (7.2) emerges from the surface formed by the wall of the air manifold (6) which is in direct contact with the interior of the combustion chamber (5) and projects a distance that allows the temperature measuring region (7.2) to be at least close to the flame.
• the measurement of the temperature measurement region (7.2) will be either the flame temperature or a temperature close to it.
• the temperature of the temperature measuring region (7.2) drops because heat of this regions is transferred both to the surroundings and along the probe (7) and in particular through the connecting portion (7.1).
• the cold point located at the connecting portion is cooled down faster because is under the influence of the air flow within the air manifold so the difference of temperature increases in a first period of time and then tend to decrease. This fast variation at the very first period of time is detected and generating a signal with very short response time, sufficient to respond by cutting off the fuel gas supply.
• the signal representative of the difference of temperature, and proportional to it, and in particular this rapid evolution due to flame extinction is processed by the processor in such a way that, upon comparing it with a threshold value, assessing the absolute value of the comparison, and verifying that it has exceeded said threshold value, it transmits a signal that commands the closing of the commanded valve (8) and, therefore, cuts off the fuel gas supply.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Gas Burners (AREA)
• Control Of Combustion (AREA)
• Feeding And Controlling Fuel (AREA)

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Citations (3)

• 2024
  • 2024-03-08 EP EP24382254.1A patent/EP4614064A1/de active Pending
• 2025
  • 2025-03-07 KR KR1020250030110A patent/KR20250136776A/ko active Pending
  • 2025-03-07 JP JP2025036832A patent/JP2025137494A/ja active Pending
  • 2025-03-10 CN CN202510277276.2A patent/CN120609056A/zh active Pending

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