US20070251467A1 - Combustion apparatus - Google Patents
Combustion apparatus Download PDFInfo
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- US20070251467A1 US20070251467A1 US11/783,461 US78346107A US2007251467A1 US 20070251467 A1 US20070251467 A1 US 20070251467A1 US 78346107 A US78346107 A US 78346107A US 2007251467 A1 US2007251467 A1 US 2007251467A1
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- Prior art keywords
- air
- combustion
- primary
- ion current
- current measuring
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- 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
- F23D14/04—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone induction type, e.g. Bunsen burner
- F23D14/08—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone induction type, e.g. Bunsen burner with axial outlets at the burner head
- F23D14/085—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone induction type, e.g. Bunsen burner with axial outlets at the burner head with injector axis inclined to the burner head axis
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- 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
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N1/00—Regulating fuel supply
- F23N1/02—Regulating fuel supply conjointly with air supply
- F23N1/022—Regulating fuel supply conjointly with air supply using electronic means
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N3/00—Regulating air supply or draught
- F23N3/08—Regulating air supply or draught by power-assisted systems
- F23N3/082—Regulating air supply or draught by power-assisted systems using electronic means
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- 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
- F23N5/12—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods
- F23N5/123—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods using electronic means
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- 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
- F23C2900/06041—Staged supply of oxidant
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Combustion (AREA)
- Regulation And Control Of Combustion (AREA)
- Gas Burners (AREA)
Abstract
An object of the present invention is to provide a combustion apparatus capable of certainly detecting a shortage of an amount of air relative to that of fuel gas.
A combustion apparatus 1 is adapted to perform a primary combustion of air-fuel mixture in an oxygen-deficient condition composed of mixture of primary air and fuel gas and further perform a secondary combustion upon supply of secondary air 67, including a first ion current measuring element 65 positioned at a site where a flame of the primary combustion is to take place and a second ion current measuring element 66 adjacent to a secondary air supply opening 20, 21, 63, or 64 for supplying the secondary air 67, so as to control at least one selected from a group consisting of (a) a ratio of an amount of the primary air to that of the secondary air, (b) a total amount of the primary and the secondary air, and (c) an amount of the fuel gas based on measured values by the first and the second ion current measuring elements 65 and 66.
Description
- 1. Field of the Invention
- The present invention relates to a combustion apparatus, and more particularly to a combustion apparatus recommended to be used in a water heater or a bath heater.
- 2. Description of the Related Art
- A combustion apparatus is a main component in a water heater or a bath heater and in widespread use at home as well as at factories.
- Recently, environmental destruction resulting from acid rain has become a grave social issue, and thus, there is a pressing need to reduce a total amount of emission of NOx (nitrogen oxides).
- There is a combustion apparatus employing a combustion system called the “thick and thin fuel combustion” method adapted to be used in a small device such as a water heater and to reduce NOx emissions.
- The “thick and thin fuel combustion” method is designed to produce a main flame from a lean mixed gas composed of fuel gas premixed with air of about 1.6 times the amount of the theoretical amount of air and arrange around the main flame an auxiliary flame produced from a rich mixed gas with a small amount of mixed air and a high gas concentration.
- A combustion apparatus based on the thick and thin combustion is known for such a configuration as disclosed in the
patent documents - A combustion method with a less amount of NOx emissions also includes a combustion system called the “two-staged combustion” method. The “two-staged combustion” method is adapted to inject fuel gas in an oxygen-deficient condition to produce a primary flame by igniting the gas, so as to produce a secondary flame by supplying a secondary air to unburned gas.
- The
patent document 3 discloses a combustion apparatus employing such a two-staged combustion method. - Patent Document 1: JP 5-118516A
- Patent Document 2: JP 6-126788A
- Patent Document 3: JP 52-143524A
- A combustion apparatus employing the thick and thin fuel combustion method generates a less amount of NOx emissions, being well-reputed in the market, but is disadvantageous in low Turn Down Ratio (T. D. R). Especially, a combustion apparatus employing the thick and thin fuel combustion method is disadvantageous in difficulty to burn in an area with a low heating value.
- Specifically, in the thick and thin fuel combustion method, a main flame is produced from a lean mixed gas composed of fuel gas premixed with air of about 1.6 times the amount of the theoretical amount of air, as described above. The mixed gas has a low burning rate because of its leanness.
- The combustion apparatus employing the thick and thin fuel combustion method is provided with a fan for generating a lean mixed gas, but the fan would become deteriorated due to years of its use, resulting in gradually reducing its blowing volume. Further, a filter of the fan would be clogged, resulting in reducing its air blowing volume. The reduced air blowing volume reduces an amount of air in the mixed gas producing a main flame, rendering the amount of mixed air approaching the theoretical amount of air. As a result, a combustion speed of the main flame becomes more rapid. Therefore, a proximal end of a flame gradually approaches burner ports across the ages. Thus, combustion in an area with a low heating value would render a proximal end of a flame approaching to burner ports, resulting in damaging the burner ports. Consequently, a combustion apparatus employing the thick and thin fuel combustion method is forced to restrict combustion in an area with a low heating value on an anticipated aging.
- In addition, the thick and thin fuel combustion method imposes such a restriction as a narrow range of usable gas. Specifically, fuel gas supplied by a gas maker may be constituted by a single component, but in many cases, by a plurality of components. That causes different combustion speed depending on makers of fuel gas even if their amounts of heat generation (amounts of heat per unit volume) are the same among them.
- Since the thick and thin fuel combustion method produces a main flame in an air excess condition, fuel gas having a slow combustion speed might cause blow off, resulting in unstable combustion.
- In contrast, the two-staged combustion method can set a higher Turn Down Ratio than the thick and thin fuel combustion method. Further, a wide variety of fuel gas is available. However, the two-staged method burns fuel gas in an oxygen-deficient condition, resulting in unstable combustion. Provably for this reason, we found none of practical devices such as water heaters that are offered commercially and employ the two-staged combustion method.
- A combustion apparatus employing the two-staged combustion method is constituted in such a manner that a burner port assembly for producing a primary flame is surrounded by an air combustion assembly for producing a secondary flame at downstream of the primary flame.
- The conventional two-staged combustion type combustion apparatus for use in application other than in a water heater uses a thermocouple as a means to assess combustion condition, but the thermocouple cannot detect a shortage of air supply, and thus, an ion current measuring element (probe) for measuring ion current (also called “ionization current”) in flame is mainly employed instead of the thermocouple in recent years. Ions exist in flame, which is electrically a conductor. An ion content in a primary flame and an ion content in a secondary flame are measured, so as to calculate a difference between the two contents. That is why ion current measuring elements are necessary to be positioned at two sites of the combustion apparatus.
- A water heater in recent years has been miniaturized. A combustion apparatus incorporated in a water heater has been required to be miniaturized along with that. Two ion current measuring elements positioned in a combustion apparatus would get closer to each other. Thus, ion current is more likely to flow between both of the measuring elements, resulting in having significant bad effects on assessment of combustion condition.
- An object of the present invention made in view of the problems and drawbacks in the art described above is therefore to provide a combustion apparatus capable of certainly detecting a shortage of an amount of air relative to that of fuel gas.
- In order to solve the problems and drawbacks described above, an aspect of the present invention provided herein is a combustion apparatus adapted to perform a primary combustion of air-fuel mixture in an oxygen-deficient condition composed of mixture of primary air and fuel gas and further perform a secondary combustion upon supply of secondary air, including a first ion current measuring element positioned at a site where a flame of the primary combustion is to take place, and a second ion current measuring element adjacent to a secondary air supply opening for supplying the secondary air, so as to control at least one of supplied air and fuel gas based on measured values by the first and the second ion current measuring elements.
- The first ion current measuring element penetrates through high-temperature flame front of the primary flame with the distal end situated within the primary flame. The primary flame includes unburned air-fuel mixture therewithin, being at low temperature. Consequently, the first measuring element does not reach an extremely high temperature in totality. Further, the second ion current measuring element is cooled by the secondary air. That avoids deformation of the first and the second measuring elements resulted from high temperature. Further, combustion condition of the combustion apparatus is detected and anomalous combustion is appropriately normalized.
- By provision of both of the ion current measuring elements as described above, output values obtained from the first and the second measuring elements do not change in synchronism with reduction of an amount of supplied air, so as to certainly detect that an amount of supplied air is reduced.
- As to the supplied air, adjustment of its supply or a ratio of distribution of the primary air and the secondary air can be controlled.
- The combustion apparatus may be adapted to control at least one selected from a group consisting of (a) a ratio of an amount of the primary air to that of the secondary air, (b) a total amount of the primary and the secondary air, and (c) an amount of the fuel gas.
- Such an arrangement produces an effect similar to the above-mentioned one. Further, the present arrangement controls at least one selected from a group consisting of a ratio of an amount of the primary air to that of the secondary air, a total amount of the primary and the secondary air, and an amount of the fuel gas based on measured values by the first and the second ion current measuring elements, so as to appropriately normalize combustion condition even if the combustion condition may become anomalous.
- By provision of both of the ion current measuring elements as described above, output values obtained from the first and the second measuring elements do not change in synchronism with reduction of an amount of supplied air, so as to certainly detect that an amount of supplied air is reduced.
- The combustion apparatus may include at least one premixer adapted to introduce thereinto the fuel gas along with the primary air to generate the air-fuel mixture in an oxygen-deficient condition, at least one air passage member of a wall shape having the secondary air supply opening for supplying the secondary air at its distal end, at least one burner port assembly arranged between two of the air passage members or between the air passage member and another wall, and at least one combustion part formed by a space enclosed by the burner port assembly and the air passage member, wherein the air-fuel mixture is discharged from the burner port assembly into the combustion part to perform the primary combustion and further perform the secondary combustion upon supply of the secondary air from the secondary air supply opening of the air passage member.
- The combustion apparatus in the present aspect includes the first ion current measuring element positioned at a site where a flame of the primary combustion is to take place and the second ion current measuring element adjacent to the air supply opening, so that the both measuring elements do not reach a high temperature. Especially, the second measuring element is cooled by the secondary air supplied from the air supply opening, whereby high-temperature deformation is avoided.
- Further, during a normal combustion, the secondary air protects the second measuring element from flame, thereby preventing flow of weak ion current between the first and the second measuring elements, and whereby anomalous combustion in a shortage of air is certainly detected.
- Still further, in the case of detection of anomalous combustion based on measured values by the both measuring elements, the combustion apparatus is designed to control at least one selected from a group consisting of a ratio of an amount of the primary air to that of the secondary air, a total amount of the primary and the secondary air, and an amount of the fuel gas, thereby normalizing the anomalous combustion.
- Another aspect of the present invention is a combustion apparatus adapted to perform a primary combustion of air-fuel mixture in an oxygen-deficient condition composed of mixture of primary air and fuel gas and further perform a secondary combustion upon supply of secondary air, including a first ion current measuring element positioned at a site where a flame of the primary combustion is to take place, an air supply port for supplying air different from the primary air to a base of the flame of the primary combustion, and a second ion current measuring element adjacent to the air supply port, so as to control at least one of supplied air and fuel gas based on measured values by the first and the second ion current measuring elements.
- The combustion apparatus may include at least one premixer adapted to introduce thereinto the fuel gas along with the primary air to generate the air-fuel mixture in an oxygen-deficient condition, at least one air passage member of a wall shape having a secondary air supply opening, at least one burner port assembly arranged between two of the air passage members or between the air passage member and another wall, and at least one combustion part formed by a space enclosed by the burner port assembly and the air passage member, wherein the air-fuel mixture is discharged from the burner port assembly into the combustion part to perform the primary combustion, and wherein the secondary air supply opening is located at a base of the flame of the primary combustion.
- As described above, the distal end of the first measuring element penetrates through the flame front of the primary flame to be positioned within the primary flame at a relatively low temperature, so that the first measuring element does not reach at an extremely high temperature in totality. Further, the second ion measuring element is adapted to be cooled by air. Consequently, high-temperature deformation of the both measuring elements is avoided.
- The distal end of the first ion current measuring element may be curved or bent.
- It is preferable that the distal end of the first measuring element is curved or bent toward upstream of flow of fuel gas.
- The distal end of the second ion current measuring element may be curved or bent.
- It is preferable that the distal end of the second measuring element is curved or bent toward the center of a combustion area.
- The combustion apparatus may be adapted to blow air to the second ion current measuring element. By blowing of air to the second measuring element, the second measuring element is cooled by the air. That avoids high-temperature deformation. Further, air existing around the second measuring element prevents flow of ion current between the first and the second measuring elements.
- The combustion apparatus may further include a memory storing a standard value relating to difference between output values measured by the first and the second ion current measuring elements corresponding to a regulation value of emission concentration of carbon monoxide.
- The standard value may have a predetermined width. The center value of the predetermined width can be set at discretion, and can correspond with the above-mentioned difference between the output values. Having the predetermined width, the combustion apparatus readily determines whether combustion condition is normal or not.
- The combustion apparatus may be adapted to compare a calculated value of the difference with the standard value stored in the memory.
- As a result of the comparison, the combustion apparatus increases air supply and/or reduces fuel gas supply in the case that the calculated value is bigger than the standard value stored in the memory, thereby normalizing combustion of the apparatus. Further, setting a ratio of an amount of the secondary air to that of an amount of the primary air larger normalizes combustion of the apparatus.
- Conversely, in the case that the standard value stored in the memory is smaller than the calculated value, a normal combustion is performed.
- The combustion apparatus may define three routes through which air flows: a first route within the air passage member, a second route from between the premixer and the burner port assembly to the combustion part, and a third route through which air flows with the fuel gas, the first and the second routes being adapted to supply the secondary air, the third route being adapted to introduce the primary air, further including a memory for storing a standard value relating to difference between output values measured by the first and the second ion current measuring elements corresponding to a regulation value of emission concentration of carbon monoxide, being adapted to compare a calculated value of the difference with the standard value stored in the memory, and being adapted to increase supply of the secondary air flowing through the first and the second routes in the case that the calculated value is bigger than the standard value stored in the memory.
- By such an arrangement, if the calculated value indicates anomalous combustion of the combustion apparatus, the combustion apparatus increases supply of the secondary air passing through the first and the second routes to sufficiently supply oxygen, thereby normalizing combustion.
- The combustion apparatus of the present invention arranges the first ion current measuring element in the primary flame and the second ion current measuring element adjacent to the secondary air supply opening so as to blow the secondary air to the second measuring element.
- Herein, the first measuring element penetrates through high-temperature flame front with its distal end positioned within the primary flame. The primary flame includes therein unburned gas mixture, so that the temperature is low. Thus, the first measuring element does not reach an extremely high temperature in totality. Further, the second ion current measuring element is cooled by the secondary air. Consequently, both of the first and the second ion current measuring elements are not deformed by high temperature, so as to certainly detect an anomaly of combustion caused by a shortage of an amount of air relative to that of fuel gas.
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FIG. 1 is a sectional perspective view conceptually illustrating a configuration of acombustion apparatus 1 of the present invention; -
FIG. 2 is a perspective view of a combustion apparatus in a practical embodiment of the present invention; -
FIG. 3 is a plan view of a plurality of the combustion apparatus inFIG. 2 accommodated in a casing; -
FIG. 4 is a sectional view taken substantially along the lines IV-IV ofFIG. 3 ; -
FIG. 5 is a sectional view of the combustion apparatus inFIG. 2 ; -
FIG. 6 is an exploded perspective view of the combustion apparatus inFIG. 2 ; -
FIG. 7 is a sectional view of an air passage member of the present embodiment; -
FIG. 8 is a sectional perspective view of a combustion apparatus arranged with other ion current measuring elements available in embodying the present invention; -
FIG. 9 is a graph showing a relation of output values of a first and a second ion current measuring elements and an amount of carbon monoxide CO; -
FIG. 10 is a view of a controlling system for controlling an amount of air and an amount of fuel gas; -
FIG. 11 is a flow chart for assessing combustion condition of a combustion apparatus; -
FIG. 12 is a sectional perspective view of a modified combustion apparatus in which the second ion current measuring element is located at a different position from those inFIGS. 1 and 8 ; -
FIG. 13 is a flow chart for assessing combustion condition of a combustion apparatus including restriction of a blowing value; and -
FIG. 14 is a sectional perspective view conceptually illustrating a structure of a modified combustion apparatus in which the second ion current measuring element is located at a different position from those inFIGS. 1 and 8 and the first ion current measuring element is different from those inFIGS. 1 and 12 of the present invention - Now, an embodiment of the present invention will be described below in detail, making reference to the accompanying drawings. First, an outline configuration and basic functions of a combustion apparatus of the present invention will be described, referring to a schematic view of
FIG. 1 .FIG. 1 is a sectional perspective view conceptually illustrating a configuration of acombustion apparatus 1 of the present invention. - In the following descriptions, the vertical positional relationship is based on a
combustion apparatus 1 positioned upright and producing flame at an upper part thereof. Terms “upstream” and “downstream” are based on an air or fuel gas flow. A “width direction” denotes a lateral direction (a direction of an arrow “W” in the figure) with a part having the maximal area of thecombustion apparatus 1 facing the front. - The
combustion apparatus 1 of the present embodiment may be used by unitizing more than one apparatus accommodated in a casing or alone. Thecombustion apparatus 1 includes apremixer 2, aburner port assembly 3, and twoair passage members 5. In thecombustion apparatus 1, thepremixer 2 and theburner port assembly 3 are engaged with each other to constitute anintermediate member 6, which is interposed between the twoair passage members 5. However, in the actual use, a plurality of theair passage members 5 and a plurality of theintermediate members 6 are alternately arranged to form a planar shape in an order such as theair passage member 5, theintermediate member 6, theair passage member 5, theintermediate member 6, theair passage member 5, and so on. - The
premixer 2, a component of thecombustion apparatus 1, serves to premix fuel gas and air therewithin. Thepremixer 2 includes a mixingpart 7 having a curved passage and anaperture row part 10 havingapertures 8 arranged in a row. Theaperture row part 10 has a cavity of a substantially square shape in a cross section extending lengthwise and straight. -
FIG. 7 is a cross section of theair passage member 5 of the present embodiment, showing air flow therewithin. Theair passage member 5 generally has a thin wall shape. Theair passage member 5 is constituted by afirst face 11 and asecond face 12, each made of a thin plate, in such a manner that the first and the second faces 11 and 12 are connected with forming a narrow gap therebetween, the three sides except the bottom face being joined, thereby defining a cavity to be anair passage 13 inside. - Specifically, the first face (front plate) 11 and the second face (rear plate) 12 are made by folding a unitary plate. The distal end where the front plate and the rear plate meet has a sharply-angled
bent portion 14, thebent portion 14 making up atop portion 9, which extends in ridge-like lines. - The proximal end of the
air passage member 5 is opened between the plates of the first and the second faces (front and rear plates) 11 and 12, forming anair inlet 15. - In the
air passage member 5, apertures for discharging air are formed at three areas. In the case that a plurality of thecombustion apparatus 1 are arranged in parallel as described above, theair passage members 5 and theintermediate members 6 are alternately arranged to form a planar shape. The same numbers of apertures are formed at the same portions of the first and the second faces 11 and 12 of eachair passage member 5. - The apertures for discharging air are formed at the distal end, a position facing to a
first combustion part 46, and a position facing to theintermediate member 6, roughly describing. - Specifically, the plates of the first face (front plate) 11 and the second face (rear plates) 12 of the
air passage member 5 are paralleled in their most parts, but are angularly folded at their distal ends, forminginclined surfaces distal apertures secondary air 67 to asecondary flame 68. InFIG. 1 , thesecondary flame 68 is drawn inward from the tip of theair passage member 5 due to space limitation, but actually extends outward (upward inFIG. 1 ) from the tip of theair passage member 5. - The first and the
second surfaces air passage member 5, as shown inFIG. 1 , have theair passage 13 formed in such a manner as being narrower at the distal end than at the proximal end and having steps at positions corresponding to the proximal end of thefirst combustion part 46, which steps also constitute inclined surfaces 22. Air emission apertures (air supply ports, secondary air supply openings) 23 facing to a combustion part are formed at each of the steps. Theair emission apertures 23 are designed to supply a secondary air therethrough to aprimary flame 24 of thefirst combustion part 46, so as to burn part of theprimary flame 24 to produce thesecondary flame 68 within a part of thefirst combustion part 46. - Further, air emission apertures (upstream air emission apertures) 48 are formed at a position facing to the
intermediate member 6 of the first and thesecond surfaces air passage member 5, and whereby air is supplied to each side of theburner port assembly 3, so as to achieve flame stabilizing. - The
burner port assembly 3 is mainly constituted by amain body 25 anddecompression walls 26. Themain body 25 of theburner port member 3 is made by bending a piece of metal plate. Themain body 25 has atop face 30 functioning as a burner port and twoside walls top face 30 and bent at substantially 90 degree angle with respect to thetop face 30. Right and left sides of theburner port assembly 3 are closed with only a bottom face in the figure opened. Thetop face 30 of the burner port assembly 3 (or the main body 25) has an elongated shape with an A-line shape cross section and has slits regularly arranged. The slits constituteburner ports 33. Theburner ports 33 formed at the main body 25 (or the top face 30) functions as “central apertures.” - The
side walls protruding part 34 protruding outwards (in a thickness direction) at its intermediate portion. The protrudingpart 34 is formed across the full width of theburner port assembly 3. - Open ends of the
side walls FIG. 1 , each forming outside a trough (or a gutter) 38 for engagement. Thetroughs 38 have bottom walls 36 vertical to andouter walls 37 parallel to therespective side walls - The
decompression walls 26 are attached to themain body 25, as described above. Thedecompression walls 26 are fixed to therespective side walls main body 25, forminggaps 29 between therespective side walls main body 25. Thegaps 29 each have an opening at a top of the figure. The opening functions as aside opening 27. -
Apertures 35 are formed at theside walls decompression walls 26. Thegaps 29 communicate with an inner space of themain body 25 via theapertures 35. - Next, a relationship between components will be described below.
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FIG. 6 is an exploded perspective view of thecombustion apparatus 1. Referring toFIG. 6 , thecombustion apparatus 1 arranges thepremixer 2 and theburner port assembly 3 between the twoair passage members 5. - In the present embodiment, as shown in
FIG. 1 , thepremixer 2 and theburner port assembly 3 are engaged, thereby constituting theintermediate member 6. More specifically, theaperture row part 10 of thepremixer 2 is placed between theside walls burner port assembly 3. In the actual producing process, thepremixer 2 is inserted from an opening (bottom in the figure) between theside walls burner port assembly 3 to join the both members. - The
side walls aperture row part 10 have partly contact with each other by their convex and concave shapes not shown. Specifically, theaperture row part 10 is interposed between theside wall 31 and theside wall 32 via convex and concave, with thepremixer 2 and theburner port assembly 3 unified. As described above, theside walls aperture row part 10 have partly contact with each other by their convex and concave shapes, and in other words, they partly keep away from each other. The cross section inFIG. 1 shows a cross section at a site where theside walls opening row part 10 keep away from each other. - Sites corresponding to the protruding
parts 34 of theside walls opening row part 10. The protrudingparts 34 each are opposite to a row ofapertures 8 of theaperture row part 10. Thus, outsides of theapertures 8 of theaperture row part 10 keep away from theside walls spaces 39 are formed so as to be opposite to all theapertures 8. - A relatively
large space 47 is formed between theside walls aperture row part 10 and thetop face 30 of theburner port assembly 3. In the present embodiment, the mixingspaces 39 and thespace 47 downstream of theaperture row part 10 form a burner portupstream passage 49. - The
air passage members 5 are attached to the both sides of theintermediate member 6. Each of theair passage members 5 is joined with theintermediate member 6 by engaging theair inlet 15 of its proximal end with thetrough 38 of theburner port assembly 3. Specifically, theouter wall 37 of thetrough 38 is inserted into theair inlet 15 and the tip (the bottom edge in the figure) of theair passage member 5 is inserted into thetrough 38, and whereby theair passage member 5 is brought into contact with the bottom wall 36 of thetrough 38. - The
air passage member 5 and the intermediate member 6 (the burner port assembly 3) have partly contact with each other by the convex and concave shape, and thus the both members are unified. The both members have partly contact with each other as just described, and in other words, keep partly away from each other. The cross section ofFIG. 1 shows a site where theair passage member 5 and the intermediate member 6 (burner port member 3) keep away from each other so as to facilitate understanding their functions. However, at an end (the bottom edge in the figure) upstream of thecombustion apparatus 1, aspace 40 between theair passage member 5 and theintermediate member 6 are closed by the bottom wall 36 of thetrough 38. Thus, thespace 40 does not directly communicate with outside at the proximal end. - The
burner port assembly 3 is interposed between the twoair passage members 5 as described above, thetop face 30 of theassembly 3 lying below (in the figure) the top level of theair passage members 5 and, so to say, buried between theair passage members 5. Therefore, a space ahead (downstream) of thetop face 30 of theassembly 3 is partitioned by walls of twoair passage members 5. In the present embodiment, a space enclosed by thetop face 30 of theassembly 3 and twoair passage member 5 functions as thefirst combustion part 46. - A first ion current measuring element (probe) 65 and a second ion current measuring element (probe) 66, which are characteristic constituents of the present invention, are incorporated in the
combustion apparatus 1 described above. Specifically, the first ion current measuringelement 65 is arranged along a longitudinal direction of thecombustion apparatus 1 within thefirst combustion part 46 above theburner port assembly 3 and interposed between two opposingair passage members 5 and at a site where theprimary flame 24 is to take place in combustion. The second ion current measuringelement 66 is arranged adjacent to thebent portion 14 at the distal end of theair passage member 5. The first and the second ion current measuringelement first combustion part 46 at a near side or a far side of paper. - Flame has ions of burning components, being electrically conductible. The first and the second
ion measuring elements - Herein, the first measuring
element 65 penetrates through flame front with its distal end positioned within theprimary flame 24. Theprimary flame 24 includes therein unburned gas mixture, so that the temperature is lower therein than at the flame front. Thus, the first measuringelement 65 does not reach an extremely high temperature in totality. Further, the second ion current measuringelement 66 is arranged at a position where thesecondary air 67 supplied (etted) through the distal apertures (secondary air supply openings) 21 of thebent part 14 encounters (viz. adjacent to the distal apertures 21). Therefore, thesecond measuring element 66 is enveloped by thesecondary air 67, not being exposed to thesecondary flame 68. - The
secondary air 67 restricts an increase in temperature of thesecond measuring element 66. Further, thesecondary air 67 cuts off an electrical connection produced by flame of the first and thesecond measuring elements second measuring elements -
FIG. 5 is a sectional view of the combustion apparatus inFIG. 2 .FIG. 5 illustrates a condition in which the first and thesecond measuring elements combustion apparatus 1, as described above. - Procedures for assessing combustion condition using the first and the second ion current measuring
elements FIGS. 9 to 11 .FIG. 9 is a graph showing a relation of output values (microampere: μA) of the first and the second ion current measuringelements FIG. 10 is a view of a controlling system for controlling an amount of air and an amount of fuel gas.FIG. 11 is a flow chart for assessing combustion condition of a combustion apparatus. - As shown in
FIG. 9 , a regulation value of carbon-monoxide CO emissions is set so as to meet environmental standards. Specifically, the regulation value of emissions (threshold value) corresponds to a value (μA) of difference between output values measured by the first and thesecond measuring elements - In
FIG. 9 , during a normal combustion, there are many ions in theprimary flame 24 generated by combustion, so that an output value measured by the first measuring element 65 (measured ion current value) becomes higher. In contrast, most of thesecond measuring element 66 is enveloped by thesecondary air 67 and ion generation therearound is extremely few, so that an output value measured by thesecond measuring element 66 becomes much lower than that measured by the first measuringelement 65 even though thesecondary flame 68 principally involving combustion of a carbon monoxide CO or a hydrogen H exists. - If and when only an amount of air supplied by means of a
fan 41 is reduced for some reasons, an amount of emissions of unburned combustible component is increased in thefirst combustion part 46. Additionally, stretch of theprimary flame 24 causes an increased portion of the first measuringelement 65 located within theprimary flame 24 enveloped by unburned gas mixture, but a combustion temperature goes down, resulting in a lower ion concentration, whereby an output value measured by the first measuringelement 65 drops to a lower value. - In contrast, an output value measured by the
second measuring element 66 is increased because a carbon monoxide CO component generated by lack of air in theprimary flame 24 reaches thesecond measuring element 66. Thus, a value of difference between output values measured by the first and the second ion current measuringelements fan 41. - Therefore, a calculated value of difference D between both output values corresponding to a regulation value X (
FIG. 9 ) of emission concentration of carbon monoxide CO is obtained in advance by an experiment. The calculated value is stored as a threshold value (a standard value relating to output values) in amemory 76 incorporated in acontrol device 69 shown inFIG. 10 . - Then, a
CPU 74 calculates a difference between output values measured by the first and thesecond measuring elements memory 76. - If the calculated value is smaller than the threshold value, the
control device 69 determines that combustion by thecombustion apparatus 1 is normal. If the calculated value reaches or exceeds the threshold value, thecontrol device 69 determines that combustion by thecombustion apparatus 1 is anomalous. If and when thecontrol device 69 determines (assesses) combustion as an anomaly, thecontrol device 69 increases air blowing volume of thefan 41 or decreases an amount of fuel gas jetted from anozzle 42 shown inFIG. 1 by closing a fuelgas supply valve 59 or a fuel gasproportional valve 18, thereby normalizing the combustion. Herein, the threshold value may have a predetermined width “d” so that combustion is determined as an anomaly when the calculated value falls within a threshold value range (FIG. 9 ). Specifically, the width “d” may be set to a width of a concentration of carbon monoxide CO lower than a regulation value “X” so that combustion is determined as an anomaly before the calculated value reaches the regulation value “X.” - Normalization of combustion after the
control device 69 determines the combustion as an anomaly and takes measures as described above, thecombustion device 69 adjusts thefan 41 or an opening degree of the fuelgas supply valve 59 or the fuel gasproportional valve 18 so as to prevent the calculated value from reaching the threshold value. Instead, it is also possible to increase or decrease a total amount of air supplied by means of thefan 41 or regulate the air allocation to each of a first, a second, a third routes described below. Alternatively, an amount of fuel gas jetted from thenozzle 42 may be regulated. Then, promotion of awareness to users by means such as blinking an alarm lamp in the case that thecontrol device 69 determines combustion as an anomaly facilitates a rapid and appropriate maintenance. - A series of operations described above will be described in detail below, referring to a flow chart in
FIG. 11 . - Starting of operations of the
combustion apparatus 1 activates thefan 41 first, and next, fuel gas is jetted from the nozzle 42 (FIG. 1 ) to produce a gas mixture within thepremixer 2. Then, the gas mixture is ignited by an igniter 4 (FIG. 10 ), whereupon the above-mentioned primary and secondary combustions are performed. - The
control device 69 calculates a calculated value (difference between both output values) from output values measured by the first and the second ion current measuringelements memory 76. If the calculated value does not reach the threshold value (or the threshold value range), thecontrol device 69 determines the combustion as an anomaly. Then, thecontrol device 69 determines whether the calculated value reaches the threshold value or not at predetermined time intervals (for example, 0.05 to 3 second interval, or preferably 0.1 to 1 second interval) during the operations of thecombustion apparatus 1. If the calculated value reaches the threshold value (or the threshold range), the combustion is determined as an anomaly, whereupon thecontrol device 69 increases air blowing volume by means of thefan 41 or decreases an amount of supplied fuel gas. Further, thecontrol device 69 measures ion current values (output values) using the first and thesecond measuring elements combustion apparatus 1. - According to a control in the flow chart in
FIG. 11 , the difference (calculated value) between the output values is compared with the threshold value and operations such as increasing air blowing volume by means of thefan 41 are performed when the calculated value exceeds the threshold value. However, in the case of excessively increased air blowing volume, the volume would be preferably decreased to an appropriate amount. - Further, in the case of excessively restricted fuel gas supply, the gas supply would be preferably increased to an appropriate amount.
- As shown in a flow chart in
FIG. 13 , for example, a second threshold value can be set, so as to decrease air blowing volume by thefan 41 or increase fuel gas supply when the calculated value falls below the second threshold value. - Herein,
FIG. 13 is a flow chart for assessing combustion condition of a combustion apparatus including restriction of a blowing value. - In the case that output values measured by the first and the second ion current measuring
elements - It is possible to have an alarm device for giving some alarm when difference (calculated value) between output values measured by the first and the
second measuring elements - A function of the
combustion apparatus 1 provided with such the first and the second ion current measuringelements - A number of the
combustion apparatus 1 are apposed within acasing 54 as shown inFIG. 3 , with air being sent by means of thefan 41 from a bottom side inFIG. 1 . Fuel gas is introduced into theapparatus 1 through agas inlet 43 of thepremixer 2 by means of thenozzle 42. - First, air stream will be described. The air stream is shown by thin lines in
FIG. 1 . - Air blow generated by the
fan 41 is straightened throughopenings 45 of a straighteningvane 44 to be introduced into thecombustion apparatus 1 through the proximal end (bottom in the figure) of theapparatus 1. - There are three routes for air to be introduced into the
apparatus 1. The first route passes through inside theair passage member 5, the air flowing through theair inlet 15 formed at the proximal end of theair passage member 5 into theair passage member 5 and going up (toward downstream) to the distal end through theair passage 13 of theair passage member 5. - Most of the air is discharged outside through the
distal apertures - Part of the air flowing in the
air passage member 5 is discharged through theair emission apertures 23 facing to a combustion part and the air emission apertures (upstream air emission apertures) 48. - Air directed diagonally to the front of an axis line of the
apparatus 1 is discharged through theair emission apertures 23 of the inclined surfaces 22. - Further, the air discharged through the
air emission apertures 48 flows in thespace 40 between theair passage member 5 and theintermediate member 6 to the side of theburner port assembly 3. - The second route passes through inside the
intermediate member 6. - The
intermediate member 6 has such a configuration that theaperture row part 10 of thepremixer 2 is interposed between theside walls burner port assembly 3. Gaps exist between theaperture row part 10 and theburner port assembly 3 and are open at their bottoms (upstream) to formopenings 28. The air is entered through theopenings 28. - The air having entered through the
openings 28 enters the mixingspaces 39 through the gaps between theside walls aperture row part 10, reaching thespace 47 between theaperture row part 10 and thetop face 30 of theburner port assembly 3. That is, the air described above flows in the burner portupstream passage 49. Finally, the air is discharged through the slits, i.e., theburner ports 33, to thefirst combustion part 46. Part of the air having entered thespace 47 enters thegaps 29 between themain body 25 and theside walls apertures 35 formed at theside walls main body 25 and is discharged to thefirst combustion part 46 through theside openings 27. - The third route is a route for the primary air, which is introduced with fuel gas through the
gas inlet 43 of thepremixer 2. The third route is the same route as that of fuel gas (gas mixture) flow, being described below as fuel gas flow. The fuel gas flow is shown by solid arrowed lines inFIG. 1 . - Fuel gas is introduced with the primary air into the
gal inlet 43 of thepremixer 2 and mixed with air in the mixingpart 7 to be flown into theaperture row part 10. Theaperture row part 10 has a number ofapertures 8 arranged linearly, so that the fuel gas (gas mixture) having introduced thereinto is evenly discharged through each of theapertures 8. The fuel gas (gas mixture) having been discharged through theapertures 8 of therow part 10 enters the mixingspaces 39 formed between theside walls burner port assembly 3 and therow part 10 to be mixed with air flowing in the second route, reaching the burner portupstream passage 49. - The air flowing in the second route flows vertically (from bottom to top), whereas the fuel gas (mixed gas) having been discharged through the
apertures 8 of therow part 10 flows in a direction perpendicular to the air flow. Thus, the fuel gas (gas mixture) hits hard the air at the mixingspaces 39, and whereby mixing of the fuel gas with the air is facilitated. Further, each of the mixingspaces 39 extends throughout in a longitudinal direction of theaperture row part 10, thereby smoothing pressure. - After having passed through the mixing
spaces 39, the fuel gas (gas mixture) is flown into thespace 47, during which the mixing of the fuel gas (gas mixture) with the air is enhanced. After that, the fuel gas flows in the same way as the flow in the burner portupstream passage 49, entering thespace 47 between theaperture row part 10 andtop face 30 of theburner port assembly 3, and being mostly discharged through the slits (the burner ports) 33 to thefirst combustion part 46. Part of the air having entered thespace 47 enters thegaps 29 between thedecompression walls 26 and thesidewalls main body 25 through theapertures 35 formed at theside walls side openings 27 to thefirst combustion part 46. - The fuel gas (gas mixture) discharged through the
burner ports 33 are mixed with air within thepremixer 2 and further mixed with air having flown through the second route within the mixingspaces 39, and thus, being uniformed and being discharged through theburner ports 33 at a uniform rate. - However, though fuel gas (gas mixture) discharged through the
burner ports 33 is mixed with air, an amount of the air is below a theoretical amount of air. That is why fuel gas (gas mixture) discharged through theburner ports 33 is in an oxygen-deficient condition, failing in achieving complete combustion. - Ignited, the fuel gas (gas mixture) produces the
primary flame 24 at thefirst combustion part 46, so as to perform a primary combustion. However, the fuel gas is not completely burned because of insufficient oxygen as described above, resulting in generating a great deal of unburned combustible component. - The unburned combustible component is discharged outside through an opening of the
first combustion part 46. Herein, air is supplied to outside of thefirst combustion part 46 through the distal end (distal apertures 20 and 21) of theair passage member 5. Therefore, the unburned combustible component performs a secondary combustion upon oxygen (the secondary air 67) supply. In other words, an area outside of thefirst combustion part 46 functions as a secondary combustion part and produces thesecondary flame 68. - Further, in the present embodiment, air is supplied to the proximal end of the
primary flame 24, so as to produce an auxiliary flame in the proximal end of theprimary flame 24. - In the present embodiment, fuel gas is discharged to the
primary combustion part 46 not only through theburner ports 33, i.e., the “central openings,” but also through theside openings 27. However, the flow rate of fuel gas discharged through theside openings 27 is slower than that discharged through theburner ports 33. Specifically, fuel gas to be discharged through theside openings 27 enters thegaps 29 between thedecompression walls 26 and theside walls main body 25 through theapertures 35 formed at theside walls side openings 27 to thefirst combustion part 46. That restricts an amount of fuel gas entering thegaps 29. As a consequence, fuel gas discharged through theside openings 27 is small in amount, whereas theside openings 27 each have a large opening space. Thus, fuel gas discharged through theside openings 27 has a low flow rate. - Further, as described above, part of air passing though the
air passage member 5, which is the first route, is discharged through the air emission apertures (upstream air emission apertures) 48 to thespace 40 between theair passage member 5 and theintermediate member 6, reaching the side faces of theburner port assembly 3. Therefore, the side faces of theassembly 3 is richer in oxygen than other parts, ensuring that fuel gas discharged through theside openings 27 performs relatively stable combustion with reception of air supply. - Coupled with a low flow rate of fuel gas as described above, a stable auxiliary flame is produced in the vicinity of the
side openings 27. The proximal end of theprimary flame 24 is held by small flame produced in the vicinity of theside openings 27. - Still further, in the present embodiment, air having been discharged through the combustion part-facing
air emission apertures 23 stabilizes thesecondary flame 68. Specifically, in the present embodiment, theinclined surfaces 22 are located at the first and the second faces 11 and 12 of theair passage member 5 and at a site corresponding to the proximal ends of thefirst combustion part 46. Theair emission apertures 23 are formed at theinclined surfaces 22, thereby supplying air diagonally to an air direction from the proximal end of thefirst combustion part 46. Thus, the supplied air is supplied to thefirst combustion part 46 without obstructing theprimary flame 24 or the flow of unburned gas. As a consequence, part of unburned gas within thefirst combustion part 46 starts combustion and partly produces a secondary flame, which merges with the externalsecondary flame 68, thereby stabilizing thesecondary flame 68 produced outside. - Yet further, in the present embodiment, the
air emission apertures 23 are diagonally open, so that air discharged through theair emission apertures 23 does not obstruct theprimary flame 24 or the flow of unburned gas, as described above. Consequently, thesecondary flame 68 is stably produced at a distance from theair passage member 5 and does not excessively heat theair passage member 5. - The
combustion apparatus 1 of the present embodiment therefore stabilizes both the primary and thesecondary flames - The first and the second ion current measuring
elements - Now, a more practical configuration example of the present invention will be described in referring to the following figures after
FIG. 2 .FIG. 2 is a perspective view of a combustion apparatus in a practical embodiment of the present invention.FIG. 3 is a plan view of a plurality of the combustion apparatus inFIG. 2 accommodated in a casing.FIG. 4 is a sectional view taken substantially along the lines IV-IV ofFIG. 3 . The embodiment described below is practically designed for embodying the present invention and has a most recommended configuration. - A combustion apparatus shown in the figures following after
FIG. 2 has the same basic configuration and basic function as that in the above-mentioned embodiment, but is practically designed to detail. The same numerals are assigned to components that carry out the same functions as those in the foregoing embodiment, and descriptions of the duplicated functions are simplified. - A plurality of
combustion apparatus 1 shown inFIG. 2 are accommodated in parallel in acasing 54 as shown inFIGS. 3 and 4 . Each of thecombustion apparatus 1 of the present embodiment also includes apremixer 2, aburner port assembly 3, andair passage members 5. Thepremixer 2 and theburner port assembly 3 are engaged to constitute anintermediate member 6, which is interposed between the twoair passage members 5. - The
air passage member 5 has apertures for emitting air at three areas. The areas consist of the distal end, a position facing to thefirst combustion part 46, and a position facing to theintermediate member 6, roughly describing. - In the combustion apparatus as described above, fuel gas and air are appropriately and ideally distributed, thereby performing stable production of the
primary flame 24 and thesecondary flame 68. However, if thefan 41 might break down and air blowing volume might be reduced, a ratio (equivalent ratio) of an amount of fuel gas and that of air (amount of oxygen) might change, leading to worsening of combustion condition. However, according to thecombustion apparatus 1 of the present invention, an anomaly of combustion condition is certainly detected by ion current values (output values) measured by the first and the second ion current measuringelements combustion apparatus 1 runs in a closed chamber, but even in this case, the combustion apparatus embodying the present invention immediately detects an anomaly of combustion condition. - Therefore, immediately after detection of an anomaly, the
control device 69 increases air blowing volume by thefan 41 or reduces an opening degree of the fuel gasproportional valve 18 or the fuelgas supply valve 59 so as to reduce an amount of fuel gas, thus normalizing combustion. - The first and the second ion current measuring
elements FIG. 8 , for example, instead of being of a straight shape.FIG. 8 is a sectional perspective view of a combustion apparatus arranged with ion current measuring elements different from those inFIG. 1 . The curved or bent distal end detects combustion condition of theprimary flame 24 or thesecondary flame 68 more certainly. - For example, a curved or bent (flexed)
distal end 65 a of the first ion current measuringelement 65 is oriented toward the slits (burner ports 33) (downwardly, or upstream), and a curved or bent (flexed)distal end 66 a of the second ion current measuringelement 66 is oriented toward the center of the first combustion part 46 (viz. the area where the primary or thesecondary flame - When the
primary flame 24 comes up due to a shortage of air, the curved or bent (flexed)distal end 66 a of thesecond measuring element 66 ensures the effect to detect coming-up of theprimary flame 24 even if combustion is small in amount and theprimary flame 24 is small. Thedistal end 66 a of thesecond measuring element 66 curved below the horizon exerts the above-mentioned effect more than one curved horizontally toward the center of theprimary flame 24 because one curved above the horizon weakens the above-mentioned effect. - However, the
distal end 66 a curved below the horizon shortens a distance between thedistal end 66 a and the secondary air supply openings. In view of such a possibility that thedistal end 66 a hangs downward because of a high temperature of thesecond measuring element 66 caused by an anomalous combustion, it is preferable to curve thedistal end 66 a toward the center of theprimary flame 24 at the horizon. - In the example described above, the second ion current measuring
element 66 is located adjacent to the secondary air jetting apertures (distal apertures air passage member 5, but, as shown inFIG. 12 , may be located adjacent to theair emission apertures 23 facing to a combustion part.FIG. 12 is a sectional perspective view of a modified combustion apparatus in which the second ion current measuring element is located at a different position from those inFIGS. 1 and 8 . Being located adjacent to theair emission apertures 23, the second ion current measuringelement 66 is enveloped in the secondary air supplied from theair emission apertures 23 and is not exposed to flame, so that an excessive increase in temperature of thesecond measuring element 66 is avoided. That avoids high-temperature deformation of thesecond measuring element 66. Further, asecondary air 67 a supplied from theair emission apertures 23 and blown to thesecond measuring element 66 prevents approach of ions in flame to theelement 66, and further prevents conduction between the first and thesecond measuring elements combustion apparatus 1 is accurately detected. -
FIG. 14 is a sectional perspective view conceptually illustrating a structure of a modified combustion apparatus in which the second ion current measuring element is located at a different position from those inFIGS. 1 and 8 and the first ion current measuring element different from those inFIGS. 1 and 12 . In thecombustion apparatus 1 shown inFIG. 14 , thesecond measuring element 66 is located adjacent to theair emission apertures 23 facing to the combustion part (secondary air supply apertures) and a configuration except thedevice 66 is the same as that of thecombustion apparatus 1 shown inFIG. 1 . In the example shown inFIG. 14 , the distal end of the first measuringelement 65 is curved or bent below, as described above. - In the present embodiment, the
air emission apertures 23 open in an oblique direction, so that, as described above, thesecondary air 67 a does not interrupt theprimary flame 24 or the flow of unburned gas, thereby producing thesecondary flame 68 at a point distant from theair passage member 5, which is not excessively heated. Further, thesecondary air 67 a is blown to thesecond measuring element 66, thereby cooling thedevice 66. - Consequently, the
combustion apparatus 1 of the present embodiment stabilizes the primary and thesecondary flames - The combustion apparatus of the present invention is applied in a device requiring heating such as a water heater or a bath heater.
Claims (20)
1. A combustion apparatus adapted to perform a primary combustion of air-fuel mixture in an oxygen-deficient condition composed of mixture of primary air and fuel gas and further perform a secondary combustion upon supply of secondary air, comprising:
a first ion current measuring element positioned at a site where a flame of the primary combustion is to take place; and
a second ion current measuring element adjacent to a secondary air supply opening for supplying the secondary air,
so as to control at least one of supplied air and fuel gas based on measured values by the first and the second ion current measuring elements.
2. The combustion apparatus as defined in claim 1 ,
being adapted to control at least one selected from a group consisting of (a) a ratio of an amount of the primary air to that of the secondary air, (b) a total amount of the primary and the secondary air, and (c) an amount of the fuel gas.
3. The combustion apparatus as defined in claim 2 , further comprising a memory storing a standard value relating to difference between output values measured by the first and the second ion current measuring elements corresponding to a regulation value of emission concentration of carbon monoxide,
being adapted to compare a calculated value of the difference with the standard value stored in the memory, and
being adapted to perform one selected from a group consisting of (a) increasing a ratio of amount of the secondary air to that of the primary air, (b) increasing a total amount of the primary and the secondary air, and (c) reducing fuel gas supply, in the case that the calculated value is bigger than the value stored in the memory.
4. The combustion apparatus as defined in claim 1 , comprising:
at least one premixer adapted to introduce thereinto the fuel gas along with the primary air to generate the air-fuel mixture in an oxygen-deficient condition;
at least one air passage member of a wall shape having the secondary air supply opening for supplying the secondary air at its distal end;
at least one burner port assembly arranged between two of the air passage members or between the air passage member and another wall; and
at least one combustion part formed by a space enclosed by the burner port assembly and the air passage member,
wherein the air-fuel mixture is discharged from the burner port assembly into the combustion part to perform the primary combustion and further perform the secondary combustion upon supply of the secondary air from the secondary air supply opening of the air passage member.
5. The combustion apparatus as defined in claim 4 ,
defining three routes through which air flows: a first route within the air passage member, a second route from between the premixer and the burner port assembly to the combustion part, and a third route through which air flows with the fuel gas, the first and the second routes being adapted to supply the secondary air, the third route being adapted to introduce the primary air,
further comprising a memory for storing a standard value relating to difference between output values measured by the first and the second ion current measuring elements corresponding to a regulation value of emission concentration of carbon monoxide,
being adapted to compare a calculated value of the difference with the standard value stored in the memory, and
being adapted to increase supply of the secondary air flowing through the first and the second routes in the case that the calculated value is bigger than the standard value stored in the memory.
6. The combustion apparatus as defined in claim 1 ,
being adapted to blow air to the second ion current measuring element.
7. The combustion apparatus as defined in claim 1 ,
wherein the first and the second ion current measuring elements have 15 each a distal end, the distal end of the first ion current measuring element being curved or bent toward the upstream of fuel gas flow, and the distal end of the second ion current measuring element being curbed or bent toward the center of a combustion zone.
8. The combustion apparatus as defined in claim 1 , further comprising a memory storing a standard value relating to difference between output values measured by the first and the second ion current measuring elements corresponding to a regulation value of emission concentration of carbon monoxide.
9. The combustion apparatus as defined in claim 8 ,
the standard value having a predetermined width.
10. The combustion apparatus as defined in claim 8 ,
being adapted to compare a calculated value of the difference with the standard value stored in the memory.
11. The combustion apparatus as defined in claim 10 ,
being adapted to increase air supply and/or reduce fuel gas supply in the case that the calculated value is bigger than the standard value stored in the memory.
12. A combustion apparatus adapted to perform a primary combustion of air-fuel mixture in an oxygen-deficient condition composed of mixture of primary air and fuel gas and further perform a secondary combustion upon supply of secondary air, comprising:
a first ion current measuring element positioned at a site where a flame of the primary combustion is to take place;
an air supply port for supplying air different from the primary air to a base of the flame of the primary combustion; and
a second ion current measuring element adjacent to the air supply port,
so as to control at least one of supplied air and fuel gas based on measured values by the first and the second ion current measuring elements.
13. The combustion apparatus as defined in claim 12 ,
being adapted to control at least one selected from a group consisting of (a) a ratio of an amount of the primary air to that of the secondary air, (b) a total amount of the primary and the secondary air, and (c) an amount of the fuel gas.
14. The combustion apparatus as defined in claim 12 ,
being adapted to blow air to the second ion current measuring element.
15. The combustion apparatus as defined in claim 12 , further comprising:
at least one premixer adapted to introduce thereinto the fuel gas along with the primary air to generate the air-fuel mixture in an oxygen-deficient condition;
at least one air passage member of a wall shape having a secondary air supply opening for supplying the secondary air;
at least one burner port assembly arranged between two of the air passage members or between the air passage member and another wall; and
at least one combustion part formed by a space enclosed by the burner port assembly and the air passage member,
wherein the air-fuel mixture is discharged from the burner port assembly into the combustion part to perform the primary combustion.
16. The combustion apparatus as defined in claim 15 ,
being adapted to blow air to the second ion current measuring element.
17. The combustion apparatus as defined in claim 14 ,
defining three routes through which air flows: a first route within the air passage member, a second route from between the premixer and the burner port assembly to the combustion part, and a third route through which air flows with the fuel gas, the first and the second routes being adapted to supply the secondary air, the third route being adapted to introduce the primary air,
further comprising a memory for storing a standard value relating to difference between output values measured by the first and the second ion current measuring elements corresponding to a regulation value of emission concentration of carbon monoxide,
being adapted to compare a calculated value of the difference with the standard value stored in the memory, and
being adapted to increase supply of the secondary air flowing through the first and the second routes in the case that the calculated value is bigger than the standard value stored in the memory.
18. The combustion apparatus as defined in claim 17 ,
being adapted to blow air to the second ion current measuring element.
19. A combustion apparatus adapted to perform a primary combustion of air-fuel mixture in an oxygen-deficient condition composed of mixture of primary air and fuel gas and further to facilitate combustion upon supply of air different from the primary air, comprising:
a first ion current measuring element positioned at a site where a flame of the primary combustion is to take place;
an air supply port for supplying the air different from the primary air; and
a second ion current measuring element adjacent to the air supply port,
so as to control at least one of supplied air and fuel gas based on measured values by the first and the second ion current measuring elements.
20. The combustion apparatus as defined in claim 19 ,
being adapted to blow air to the second ion current measuring element.
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JP124293/2006 | 2006-04-27 | ||
JP2006124293A JP2007298190A (en) | 2006-04-27 | 2006-04-27 | Combustion device |
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US20070251467A1 true US20070251467A1 (en) | 2007-11-01 |
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US11/783,461 Abandoned US20070251467A1 (en) | 2006-04-27 | 2007-04-10 | Combustion apparatus |
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US (1) | US20070251467A1 (en) |
JP (1) | JP2007298190A (en) |
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Cited By (10)
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US20080160467A1 (en) * | 2006-01-30 | 2008-07-03 | Noritz Corporation | Combustion Apparatus |
US20140106285A1 (en) * | 2010-05-31 | 2014-04-17 | Resource Rex, LLC | Laminar Burner System |
US9562685B2 (en) * | 2010-05-31 | 2017-02-07 | Resource Rex, LLC | Laminar burner system |
US20120216793A1 (en) * | 2011-02-25 | 2012-08-30 | Lennox Hearth Products LLC | Thin flame burner for a fireplace |
US8956155B2 (en) * | 2011-02-25 | 2015-02-17 | Innovative Hearth Products Llc | Thin flame burner for a fireplace |
US20180142887A1 (en) * | 2015-06-12 | 2018-05-24 | Mitsubishi Hitachi Power Systems, Ltd. | Burner, combustion device, boiler, and burner control method |
US10591156B2 (en) * | 2015-06-12 | 2020-03-17 | Mitsubishi Hitachi Power Systems, Ltd. | Burner, combustion device, boiler, and burner control method |
US10344968B2 (en) * | 2017-05-05 | 2019-07-09 | Grand Mate Co., Ltd. | Gas mixer |
IT202100023330A1 (en) * | 2021-09-09 | 2023-03-09 | Polidoro S P A | PLATE GAS BURNER WITH LOW EMISSION OF POLLUTANTS |
WO2023037277A1 (en) * | 2021-09-09 | 2023-03-16 | Polidoro S.P.A. | Plate gas burner with low pollutant emission |
Also Published As
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---|---|
JP2007298190A (en) | 2007-11-15 |
CN101063522A (en) | 2007-10-31 |
DE102007019086A1 (en) | 2007-11-22 |
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