JP5495052B2 - Combustion device - Google Patents

Description

  The present invention relates to a combustion apparatus that can be suitably used as, for example, a component of a gas water heater, and more particularly to a so-called 1-fan / multi-burner combustion apparatus.

  A single-fan / multiple-burner combustion apparatus is provided with a plurality of burners for burning fuel, whereas the number of fans is one, and combustion air discharged from the fans is supplied to a plurality of burners. It is comprised so that it may be supplied (for example, refer patent document 1, 2). In general, fans are relatively large in size and expensive. Therefore, the combustion apparatus having the above-described configuration is preferable for promoting the downsizing of the entire apparatus and the reduction of the manufacturing cost as compared with the combustion apparatus using a plurality of fans.

  On the other hand, in the one-fan / multi-burner combustion apparatus, it is desired that the air-fuel ratio is kept constant and the combustibility is improved as in the case of other general combustion apparatuses. Therefore, conventionally, there is means for controlling the fuel supply pressure to each burner using a pressure regulating valve (see, for example, Patent Document 2). The pressure regulating valve controls the air pressure of the fan as a signal pressure and the fuel pressure to a pressure corresponding to the air pressure of the fan. According to such a configuration, for example, when the supply amount of combustion air from the fan to each burner is large and the air discharge pressure of the fan is high, the supply amount of fuel to each burner correspondingly increases, It becomes possible to make the air-fuel ratio constant.

  However, the prior art still has room for improvement as described below.

For ease of understanding, a case where the combustion apparatus includes first and second burners will be described as an example.
That is, of the first and second burners, for example, only the downstream area of the second burner may become exhausted or closed. Such a situation occurs when, for example, a fin tube type heat exchanger is provided on the downstream side of the second burner, and the gap between the fins of the heat exchanger is clogged. On the other hand, the fuel supply amount to the second burner corresponds to the differential pressure between the fuel supply pressure Ps to the second burner and the fuel ejection region pressure P2. The fuel ejection region pressure Ps is, for example, the same pressure as the signal pressure to the pressure regulating valve. Therefore, hereinafter, the signal pressure is also indicated by Ps. The fuel ejection region pressure P2 is a pressure in a region where fuel is ejected from the fuel ejection nozzle in the upstream region of the second burner. In the relationship of Ps> P2, the larger the difference between these, the larger the fuel ejection amount. When the downstream area of the second burner is exhausted, the air discharged from the fan flows more toward the first burner where the exhaust is not blocked. For this reason, the correspondence between the signal pressure Ps and the fuel ejection region pressure P2 is deviated, and the differential pressure between them increases. More specifically, as a result of the increase in the fuel injection region pressure P2 being slightly smaller than the increase in the signal pressure Ps caused by the exhaust blockage, the differential pressure between these increases. Therefore, there is a possibility that the fuel becomes rich and incomplete combustion occurs. In the prior art, there is still room for improvement in this respect.

JP-A-8-35626 JP 2003-35415 A

  The present invention has been conceived under the circumstances as described above, and is a combustion apparatus adopting a so-called single fan / multiple burner system, in which the downstream area of some of the burners has exhaust blockage or blockage. Even in such a case, an object of the present invention is to provide a combustion device that can appropriately prevent or suppress the occurrence of incomplete combustion in the burner.

  In order to solve the above problems, the present invention takes the following technical means.

  The combustion apparatus provided by the present invention includes first and second burners, a fan that supplies combustion air to the first and second burners via an air supply path, and an air discharge of the fan. A pressure control valve that controls the pressure of the fuel supplied to the first and second burners to a pressure corresponding to the signal pressure. And a partition portion that divides the air supply path into first and second air supply paths, and a part of the partition portion is configured so that the discharge port of the fan or a region in the vicinity thereof is the first and second regions. The first air supply path is capable of advancing combustion air from the first region toward the first burner, and the second air supply path. From the second region to the second It is possible to advance the combustion air towards the burner, the as a signal pressure of the pressure regulating valve, is characterized in that one of the pressure is used for the first and second regions.

According to such a configuration, the fuel supply pressure for the first and second burners is equal to one of the pressures in the first and second regions, which is used as the signal pressure of the pressure regulating valve. The following effects are obtained.
That is, in order to facilitate understanding, the case where the second region is used as the signal pressure of the pressure regulating valve will be described as an example. In this case, when the downstream area of the second burner becomes exhausted or obstructed, the pressure of the second air supply path, which is the upstream area of the second burner, rises. It can be generated in substantially the same way in each place. This is because the second air supply path is partitioned from the first air supply path in a predetermined state via a partition portion. By such an action, the fuel jet region pressure of the second burner and the pressure in the second region can be maintained in an appropriate constant relationship, and the differential pressure between them can be reduced. When the downstream region of the second burner is fully closed, the fuel supply can be stopped by setting the difference between the fuel ejection region pressure of the second burner and the fuel supply pressure to zero. For this reason, the air-fuel ratio in the second burner can be kept constant to avoid fuel richness, and incomplete combustion can be prevented appropriately.
On the other hand, unlike the above, when the downstream area of the first burner becomes exhausted or closed, the pressure in the second area increases as the pressure in the first air supply path, which is the upstream area, increases. In addition, the fuel jet region pressure of the first burner and the fuel supply pressure (for example, the same as the pressure in the second region) are maintained in an appropriate substantially constant relationship, and the effect of reducing these differential pressures can be expected. . Such an effect becomes remarkable when the first burner has a higher maximum combustion capacity than the second burner, as will be described later. Even when the downstream region of the first burner becomes exhausted or closed, the effect of suppressing the incomplete combustion in the first burner can be expected by maintaining the air-fuel ratio substantially constant.
As understood from this, according to the present invention, one of the first and second burners (when the pressure in the first region is the signal pressure of the pressure regulating valve). Is the first burner, and is the second burner when the pressure in the second region is a signal pressure), the conventional technology is used when the downstream region becomes exhausted or obstructed. In contrast, incomplete combustion in the burner can be prevented almost certainly. In addition, even when the downstream area of the other burner becomes exhausted or closed, an effect that can suppress incomplete combustion to some extent can be expected.

  In the present invention, preferably, in the case where the burner on the side having the maximum combustion capacity among the first and second burners is the first burner, the first region is more than the second region. The channel cross-sectional area is increased.

  According to such a configuration, the supply amount of the combustion air is increased for the first burner having the largest maximum combustion capacity, and the second burner having the smaller maximum combustion capacity is compared with the first burner. However, it is possible to easily reduce the supply amount of combustion air.

  In the present invention, preferably, the pressure in the second region is used as the signal pressure of the pressure regulating valve.

According to such a configuration, the following effects can be obtained.
That is, during normal operation of the combustion apparatus, a large amount of combustion air is supplied toward the first burner having the maximum maximum combustion capacity. For this reason, when the upstream area of the first burner becomes exhausted or closed, this phenomenon has a great influence on the entire air supply path, and the first air supply as the downstream area of the first burner is large. As the road pressure rises, the pressure in the second region also rises correspondingly, and the correspondence between these pressures can be maintained in an appropriate relationship. When the upstream region of the first burner is fully blocked, the fuel supply can be stopped by bringing the pressure in the second region corresponding to the fuel supply pressure to be almost the same as the fuel injection region pressure. is there. In the above configuration, when the pressure in the first region is not used as the signal pressure of the pressure regulating valve, the first burner is used when the downstream region of the first burner becomes exhausted or closed. It is possible to more appropriately prevent or suppress the occurrence of incomplete combustion.

  In the present invention, preferably, the ratio of the channel cross-sectional areas of the first and second regions is substantially the same as the ratio of the maximum combustion capacity of the first and second burners.

  According to such a configuration, the combustion air discharged from the fan can be distributed and supplied to the first and second burners at a ratio commensurate with their maximum combustion capacity. It is more preferable to improve.

  In the present invention, it is preferable that a part of the partition part enters the discharge port of the fan, and the first and second regions are provided in the discharge port.

  According to such a configuration, a part of the partition portion does not enter the discharge port of the fan and the first and second regions are provided outside the discharge port as compared with the first and second regions. The pressure in the second region can more accurately correspond to the amount of combustion air supplied to the first and second burners. Therefore, it is more preferable for making the air-fuel ratio constant.

  In this invention, Preferably, the said 1st and 2nd area | region is located in a line with the width direction of the rotary blade of the said fan on both sides of the said partition part.

In a fan such as a sirocco fan or a turbo fan, in general, the air discharge amount at each part of the discharge port is not uniform and often varies. The degree of variation also has a characteristic that it varies due to the rotational speed of the fan. However, this variation in the air discharge amount is unlikely to occur in the width direction of the rotary blade, and is often large in the direction intersecting this. According to the above configuration, the air flow rates in the first and second regions are not greatly affected by the variation in the air discharge amount seen in the fan itself, and combustion is performed for each of the first and second burners. It becomes easy to appropriately supply a desired amount of working air.

  Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.

It is a schematic sectional drawing which shows an example of the combustion apparatus which concerns on this invention. It is a principal part schematic sectional drawing which shows the other example of this invention. It is a schematic explanatory drawing which shows the other example of this invention. It is a schematic explanatory drawing which shows the other example of this invention.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  A combustion apparatus C shown in FIG. 1 constitutes a gas hot water supply apparatus in combination with heat exchangers 8A and 8B for heating hot water. A can body 1, first and second bodies arranged in the can body 1 are shown in FIG. Burners B1 and B2, a fan 2 attached to the bottom of the can 1, a pressure regulating valve V provided in the fuel gas supply path 3, and two upper and lower partitions provided in the can 1 4a and 4b. Of the two partition portions 4a and 4b, the lower partition portion 4b corresponds to an example of a partition portion in the present invention. However, it is also possible to adopt a configuration in which the two partition portions 4a and 4b are integrally connected.

  The first and second burners B1 and B2 are both gas burners, and their downstream areas (the downstream areas in the flow direction of combustion gas or combustion air, and the upper side of the gas burner in the drawing) are the upper partitions 4a. And is divided into first and second combustion gas flow paths 10a and 10b. The heat exchangers 8A and 8B perform heat recovery from the combustion gas generated by the first and second burners B1 and B2. As a result, the hot water supplied to the water inlets 83a and 83b is heated and discharged from the water outlets 84a and 84b. The combustion gas that has finished the heat recovery is discharged from the exhaust port 11 at the top of the can 1. The heat exchangers 8A and 8B are configured using finned tubes, for example, and have primary heat exchange parts 81a and 81b for sensible heat recovery and secondary heat exchange parts 82a and 82b for latent heat recovery. ing. The heat exchanger 8A and the first burner B1 are for general hot water supply, for example, whereas the heat exchanger 8B and the second burner B2 are for floor heating, for example. For this reason, the first burner B1 has a larger maximum combustion capacity than the second burner B2, and the heat exchangers 8A and 8B and the first and second combustion gas flow paths 10a and 10b correspond to it. The size is different.

  A fuel distribution casing 5 is provided below the first and second burners B1 and B2. The fuel gas that has passed through the pressure regulating valve V flows into the casing 5 and then proceeds toward the first and second burners B1 and B2, and is mixed with the combustion air supplied from the fan 2 in the process. Is done. This air-fuel mixture is supplied to the first and second burners B1, B2. The fuel gas ejection amount for the first burner B1 corresponds to the differential pressure between the fuel ejection region pressure P1 and the fuel gas supply pressure Ps. The fuel gas supply pressure Ps is, for example, the same as the pressure Ps and the signal pressure Ps in the second region 13a described later. The fuel gas ejection amount for the second burner B2 corresponds to the differential pressure between the fuel ejection region pressure P2 and the fuel gas supply pressure Ps. The casing 5 is provided with a plurality of electromagnetic valves 52 (in the drawing, the electromagnetic valve 52 corresponding to the first burner B1 is shown in an open state, and the electromagnetic valve 52 corresponding to the second burner B2 is shown in a closed state. With these opening / closing operations, it is possible to switch on / off the fuel gas supply from the casing 5 to the predetermined region of the first and second burners B2.

  A space from the discharge port 20 of the fan 2 to the first and second burners B1 and B2 is an air supply path 12. The lower partitioning portion 4b is for partitioning the air supply path 12 into first and second air supply paths 12a and 12b, and is configured using, for example, a metal plate. The lower end portion 40 of the partition portion 4 b enters the inside of the discharge port 20 of the fan 2. Thus, the inside of the discharge port 20 is partitioned as the first and second regions 13a and 13b. The 1st air supply path 12a advances the combustion air which passed the 1st area | region 13a toward 1st burner B1. Similarly, the 2nd air supply path 12b advances the combustion air which passed 2nd area | region 13b toward 2nd burner B2. The lower end portion 40 of the partition portion 4b is biased to the left side of the drawing with respect to the center of the discharge port 20 of the fan 2, and the ratio of the channel cross-sectional areas a1 and a2 of the first and second regions 13a and 13b is the first. And the ratio of the maximum combustion capacity (maximum heating power) of the second burners B1 and B2. For this reason, in this embodiment, it is in the relationship of a1> a2.

  The fan 2 is a sirocco fan or a turbo fan, for example, and has a structure in which a rotary blade 23 driven by a motor M is accommodated in a casing 22 having an air inlet 21. The fan 2 is set so that the direction in which the first and second regions 13 a and 13 b are aligned is the width direction of the rotary blade 23. Of course, the direction of the fan 2 may be set as shown in FIG. 2, for example. In the figure, the fan 2 is likely to have a relatively large variation in air discharge amount between a position close to the so-called jaw 24 and a position on the opposite side. For this reason, in the configuration of FIG. 2, the air passage amounts of the first and second regions 13a and 13b may not easily correspond to the ratio of the channel cross-sectional areas a1 and a2. On the other hand, if the direction of the fan 2 shown in FIG. , A2 exactly correspond to the ratio.

  The pressure regulating valve V inputs the downstream secondary pressure (fuel gas pressure Ps in the casing 5) to the port 60 without being affected by fluctuations in the primary pressure upstream of the fuel gas supply path 3. It has a function of setting a value corresponding to the signal pressure Ps (the same in this embodiment). That is, the higher the signal pressure Ps, the larger the opening degree of the valve body 62. The structure itself of the pressure regulating valve V can be the same as that described in Patent Document 2, for example, and detailed description thereof is omitted. The port 60 is connected to the second region 13 b via the tube body 61. As a result, the pressure Ps in the second region 13b is set to the signal pressure Ps of the pressure regulating valve V.

  Next, the operation of the combustion apparatus C configured as described above will be described.

  First, when the fan 2 is driven and the first and second burners B1 and B2 are driven and burned by the supply of the fuel gas, the pressure regulating valve V sets the fuel gas supply pressure Ps to the second region 13b. The pressure is controlled to Ps. Therefore, during normal operation, the air-fuel ratio can be kept constant in each of the first and second burners B1, B2.

Next, when the gap between the fins of the heat exchanger 8B is clogged and the downstream area of the second burner B2 becomes exhausted or closed, the pressure in the second air supply path 12b increases. Since the second air supply path 12b is partitioned from the first air supply path 12a via the partition portion 4b, the pressure increase in the second air supply path 12b is caused by the second air supply path 12b. It can be generated in substantially the same manner at various points 12b. For this reason, it is possible to maintain the fuel ejection region pressure P2 and the pressure Ps of the second region 12b in an appropriate relationship, and to reduce the differential pressure between them. When the second combustion gas flow path 10b is fully blocked, the difference between the fuel injection region pressure P2 and the pressure fuel supply pressure Ps can be made zero, and the fuel gas supply can be stopped. Thus, in this combustion apparatus C, even if the heat exchanger 8B is clogged and the amount of combustion air supplied to the second burner B2 decreases, the fuel gas supply to the second burner B2 Is not excessive, and incomplete combustion is appropriately prevented in the second burner B2.

  On the other hand, unlike the above, when the fin of the heat exchanger 8A is clogged and the downstream area of the first burner B1 becomes exhausted or closed, the pressure of the first air supply path 12a is increased. To rise. On the other hand, during the normal operation of the combustion apparatus C, a large amount of combustion air is supplied toward the first burner B1 having a large maximum combustion capacity, and the air circulation amount of the first air supply path 12a is the second amount. It is considerably larger than the air supply path 12b. For this reason, when the upstream region of the first burner becomes exhausted or closed, the pressure Ps of the second region 13b increases correspondingly as the pressure of the first air supply passage 12a increases. The correspondence relationship between these pressures is maintained in an appropriate relationship, and the air-fuel ratio can be made constant. When the upstream region of the first burner B1 is fully blocked, the fuel supply pressure Ps can be made almost the same as the fuel ejection region pressure P1. Therefore, in this combustion apparatus C, when the pressure in the first region 13a is not used as the signal pressure of the pressure regulating valve V, the downstream region of the first burner B1 becomes exhausted or closed. Can appropriately prevent incomplete combustion from occurring in the first burner B1.

  As described above, in the first and second regions 13a and 13b, the ratio of the channel cross-sectional areas a1 and a2 is substantially the same as the ratio of the maximum combustion capacity of the first and second burners B1 and B2. is there. For this reason, the combustion air discharged from the fan 2 can be appropriately distributed and distributed to the first and second burners B1, B2 at a ratio corresponding to their maximum combustion capacity. As a result, it is possible to appropriately avoid the shortage of combustion air in the first and second burners B1 and B2, and to improve the combustion performance. In addition, as described in comparison with FIG. 2, the first and second regions 13 a and 13 b are formed in a state in which the first and second regions 13 a and 13 b are aligned in the width direction of the rotary blade 23 of the fan 2. The amount of combustion air supplied toward the first and second burners B1 and B2 can be made to accurately correspond to the ratio of the flow path cross-sectional areas a1 and a2.

  3 and 4 show another embodiment of the present invention. In these drawings, elements that are the same as or similar to those in the above embodiment are given the same reference numerals as in the above embodiment.

  In the embodiment shown in FIG. 3, the fan 2 is not arranged directly under or near the upper partition 4a, and is offset by a relatively large dimension L1 in the direction in which the first and second burners B1, B2 are arranged. Has been. For this reason, the lower partition 4b has an inclined portion 41 that approaches the fan 2 from the upper partition 4a. As already described, the upper and lower partition portions 4a and 4b may be integrated or separated. According to the present embodiment, compared with the configuration shown in FIG. 1, although there is a disadvantage that the inclined portion 41 is provided in the lower partition portion 4 b or the size of the partition portion 4 b is increased, the present invention is The intended action can be obtained. From the viewpoint of eliminating the above disadvantages, the fan 2 is provided directly below or in the vicinity immediately below the boundary portion (the upper partitioning portion 4a) between the first and second burners B1 and B2, as in the embodiment of FIG. It is preferable.

  In the embodiment shown in FIG. 4, in addition to the first and second burners B1 and B2 and the heat exchangers 8A and 8B, a third burner B3 and a corresponding heat exchanger 8C are further provided. Yes. The downstream areas and the upstream areas of the first and third burners B1 and B3 are partitioned by integral or separate partition portions 4c and 4d, and the third combustion gas flow path 10c and the third An air supply path 12c is formed. Lower ends 40 and 42 of the lower partitions 4b and 4d divide the inside of the discharge port 20 of the fan 2 into first to third regions 13a to 13c.

According to the present embodiment, in addition to the first and second burners B1, B2, the third burner B3
Also, the combustion air can be appropriately supplied from the fan 2. Since the fuel gas supply pressure Ps for the third burner B3 is controlled by the same principle as the fuel gas supply Ps for the first burner B1, the air-fuel ratio can be kept constant in the third burner B3. Is possible. As will be understood from the present embodiment, the present invention may be configured to further include one or a plurality of burners in addition to the first and second burners. In short, if two or more burners are provided, the present invention can be suitably applied. Of course, in the case where three or more burners are provided, as long as two burners (first and second burners) correspond to the configuration intended by the present invention, it is assumed that another burner other than these burners is used. Even if the configuration does not correspond to the intended configuration of the invention, it is included in the technical scope of the present invention.

  The present invention is not limited to the contents of the above-described embodiment. The specific configuration of each part of the combustion apparatus according to the present invention can be variously changed in design.

  For example, it is preferable that a part of the partition portion enters the inside of the discharge port of the fan, and the inside of this discharge port is partitioned as the first and second regions, but is not limited thereto. Even in a configuration in which a part of the partition portion does not enter the inside of the discharge port and a region near the outside of the discharge port is partitioned into the first and second regions, the intended effect of the present invention can be obtained. Therefore, the signal pressure extraction location of the first and second pressure regulating valves is not limited to the inside of the discharge port of the fan but can be outside the discharge port.

  In the present invention, as in the embodiment shown in FIG. 1, when the first burner has a larger maximum combustion capacity than the second burner, the pressure in the second region corresponding to the second burner is set. It is preferable to use it as the signal pressure of the pressure regulating valve. According to such a configuration, even if any downstream region of the first and second burners becomes exhausted or closed, it is appropriately avoided that the fuel is rich, and incomplete combustion is prevented or suppressed. Because it can be done. However, the present invention is not limited to this. For example, when the pressure in the first region is used as the signal pressure of the pressure regulating valve, incomplete combustion occurs in the first burner when the downstream region of the first burner becomes exhausted or closed. The effect of preventing the occurrence of is very high. For this reason, for example, when there is a situation where the exhaust burn-off is more likely to occur on the first burner side than on the second burner side, the pressure in the first region is deliberately taken into account. It can also be used as the signal pressure of the pressure regulating valve.

  The first and second burners and the specific types and structures of the fans are not limited. Each of the first and second burners referred to in the present invention may not be a single burner, and each is an aggregate of a plurality of burners (first burner group, second burner group). Of course. As the pressure regulating valve, a valve having a function capable of controlling the pressure of the fuel supplied toward the first and second burners to a pressure corresponding to a predetermined signal pressure may be used. The specific structure is not limited. As for the exhaust port of the combustion gas, a partition part (for example, a part corresponding to the partition part 4a of the previous embodiment) is used to correspond to the combustion gas flow path in the downstream area of each of the first and second burners. You may make it partition into two area | regions. Further, by providing a plurality of exhaust ports, it is also possible to adopt a configuration in which the plurality of exhaust ports are individually arranged corresponding to the combustion gas flow paths in the downstream areas of the first and second burners.

  The combustion apparatus according to the present invention can be configured, for example, as a reverse combustion type (a system in which the combustion gas generated by the burner travels downward), and the direction in which the combustion air and the combustion gas travel is limited upward. Not. Further, the combustion apparatus according to the present invention does not need to be used for a hot water supply apparatus, and can be configured as a combustion apparatus for a hot air apparatus or an incinerator, for example, and a specific application is not limited.

C Combustors B1, B2 First and second burners V Pressure regulating valves a1, a2 Channel cross-sectional area (of first and second regions)
2 Fan 4b Partition 12 Air supply path 12a, 12b First and second air supply paths 13a, 13b First and second regions 20 Discharge port (of fan)
23 Rotating blade (fan)

Claims (6)

First and second burners;
A fan for supplying combustion air to the first and second burners via an air supply path;
A pressure regulating valve that controls the air discharge pressure of the fan as a signal pressure and controls the pressure of the fuel supplied toward the first and second burners to a pressure corresponding to the signal pressure;
A combustion device comprising:
A partition portion for partitioning the air supply path into first and second air supply paths;
A part of the partition portion is provided so as to partition the discharge port of the fan or the vicinity thereof into first and second regions, and the first air supply path extends from the first region to the first region. The combustion air can be advanced toward the second burner, and the second air supply path can advance the combustion air from the second region toward the second burner. And
The combustion apparatus according to claim 1, wherein the pressure of either one of the first and second regions is used as the signal pressure of the pressure regulating valve.   Of the first and second burners, in the case where the burner on the side with the largest maximum combustion capacity is the first burner, the flow passage cross-sectional area of the first region is larger than that of the second region. The combustion apparatus according to claim 1.   The combustion apparatus according to claim 2, wherein the pressure in the second region is used as the signal pressure of the pressure regulating valve.   4. The ratio according to claim 1, wherein a ratio of flow path cross-sectional areas of the first and second regions is substantially the same as a ratio of maximum combustion capacity of the first and second burners. Combustion device.   The part of the partition part enters the inside of the discharge port of the fan, and the first and second regions are provided inside the discharge port. Combustion equipment.   The combustion apparatus according to any one of claims 1 to 5, wherein the first and second regions are arranged in the width direction of the rotary blades of the fan with a part of the partition portion interposed therebetween.

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