Premixing device and combustion device comprising same

Abstract

A premixing device PR comprises a premixing device body part A that is connected to a discharge side of a fan 5 and has a gas passage 19 and a fuel gas outflow port 23, a pressure adjustment valve V that controls the supply pressure of a fuel gas, a pressure-receiving part formation part 32 that has a pressure-receiving part 32a that is a recessed opening that receives the air pressure inside the gas passage 19, a plurality of support parts 31 that support the pressure-receiving part formation part 32, a signal pressure transmission path SP that includes a communication passage 35 provided inside the plurality of support parts 31 and transmits the air pressure received at the pressure-receiving part 32a to the pressure adjustment valve V as a signal pressure, and a baffle part 33 that is provided downstream of the pressure-receiving part 32a in the airflow direction and can turn an incoming airflow into a swirling or turbulent flow. As a result, the air pressure of the gas passage 19 can be used as an accurate signal pressure Ps for the pressure adjustment valve V for the fuel gas, and the fuel gas can be sufficiently stirred and mixed with air.

Description

Technical Field

[0001] The present disclosure relates to a premixing device and a combustion device including the same.

[0002] Here, "premixing" is processing for mixing air and fuel gas in advance and generating a combustible mixture for the purpose of performing premixing combustion.Related Art

[0003] As an example of a premixing device, there is one described in Patent Document 1.

[0004] In the premixing device described in Patent Document 1, a premixing device body part is connected to an intake side of a fan. The premixing device body part has a configuration in which a gas passage through which air flows by driving of the fan is formed inside, and a fuel gas outlet is provided facing the gas passage. Thus, it is possible to generate a mixture of air and fuel gas. The premixing device body part includes a probe for sensing air pressure within the gas passage. A tip of the probe is a pressure receiving part of a concave opening shape that receives air pressure. The air pressure received at the pressure receiving part is used as a signal pressure of a pressure adjustment valve provided in a fuel gas supply path.

[0005] According to such a configuration, it is possible to control a fuel gas supply pressure as a secondary pressure of the pressure adjustment valve to a pressure corresponding to the air pressure in the gas passage, and to stabilize an air-fuel ratio.

[0006] However, in the aforementioned conventional technology, there is still room for improvement as described below.

[0007] Firstly, the probe described in Patent Document 1 is a single pipe body having an approximately L-shape in side view. The probe is attached in a manner (cantilever support manner) in which a portion of the probe penetrates a peripheral wall part of the gas passage. Hence, the pressure receiving part located at the tip of the probe is likely to vibrate under the influence of air flow. Here, when the pressure receiving part vibrates, in the case where the air pressure received at the pressure receiving part is utilized as the signal pressure of the pressure adjustment valve, the signal pressure becomes inappropriate including an error caused by vibration. Accordingly, it is difficult to perform highly precise control for stabilizing the air-fuel ratio.

[0008] Secondly, it is desired that a mixture (combustible mixture) generated in the premixing device be one in which air and fuel gas are sufficiently stirred and mixed. Here, in Patent Document 1, since the premixing device body part is provided on the intake side of the fan, the mixture of air and fuel gas is sufficiently stirred and mixed at a stage of passing through the fan. However, in Patent Document 1, in the case where the premixing device body part is provided on a discharge side of the fan and the mixture does not pass through the fan, it is difficult to actively stir and mix air and fuel gas. As a result, there is a risk that the combustibility of the mixture may be reduced.

[0009] As one implementation means for realizing a low-carbon society, it is conceivable to use hydrogen or hydrogen-containing gas as fuel gas. However, since the hydrogen or hydrogen-containing gas is prone to ignition, in the case where fuel gas is hydrogen or hydrogen-containing gas, it is desired to arrange the premixing device body part (mixing part of air and fuel gas) on the discharge side of the fan from the viewpoint of safety. In contrast, the premixing device of Patent Document 1 is not suitable for use in such a manner.Prior Art DocumentsPatent Documents

[0010] Patent Document 1: Japanese Patent No. 6673863 Patent Document 2: Japanese Patent Laid-Open No. 2010-107174 Patent Document 3: Japanese Publication of Examined Patent Application No. S58-43655 SUMMARY OF INVENTIONTechnical Problem

[0011] An object of the present disclosure is to provide a premixing device and a combustion device including the same, in which the premixing device enables highly precise control for stabilizing an air-fuel ratio so that air pressure of a gas passage can be utilized as an accurate signal pressure for a pressure adjustment valve of fuel gas, and also enables sufficient stirring and mixing of air and fuel gas even if a premixing device body part is connected to a discharge side of a fan. Solution to Problem

[0012] In order to solve the above problem, the present disclosure employs the following technical means.

[0013] The premixing device provided by a first aspect of the present disclosure is characterized by including: a fan; a premixing device body part, connected to a discharge side of the fan, having formed therein a gas passage through which air flows by driving of the fan, and provided with a fuel gas outlet at a terminal end of a fuel gas supply path in a manner enabling fuel gas to flow into the gas passage and be mixed with the air; a pressure adjustment valve, provided in the fuel gas supply path and controlling a fuel gas supply pressure to a pressure corresponding to a signal pressure; multiple support parts, respectively provided to protrude from an inner peripheral wall part of the gas passage toward a central region of the gas passage, and arranged at intervals from each other in a circumferential direction of the gas passage; a pressure receiving part formation part, supported by the multiple support parts and provided in the gas passage, including a pressure receiving part of a concave opening shape that receives air pressure at a position upstream in an air flow direction from the fuel gas outlet; a communication path, provided inside at least one of the multiple support parts and communicating with the pressure receiving part; a signal pressure transmission path, configured to include the communication path, and transmitting, as the signal pressure, the air pressure received at the pressure receiving part, to the pressure adjustment valve; and a baffle part, provided at a portion downstream in the air flow direction from the pressure receiving part and capable of turning incoming air flow into swirl flow or turbulent flow.

[0014] Preferably, the premixing device according to the present disclosure includes, as the communication path, multiple communication paths provided inside each of the multiple support parts.

[0015] Preferably, in the pressure receiving part formation part and the multiple support parts, a width in an axial length direction of the gas passage is larger than a width as viewed along an axial length direction of the gas passage.

[0016] Preferably, the pressure receiving part is formed in an upstream side portion in the air flow direction of the pressure receiving part formation part; the baffle part is provided in a downstream side portion in the air flow direction of the multiple support parts and / or the pressure receiving part formation part.

[0017] Preferably, the baffle part is configured as multiple convex portions that are located between the multiple support parts as viewed along an axial length direction of the gas passage and protrude radially outward of the pressure receiving part formation part from the pressure receiving part formation part.

[0018] Preferably, a portion of the baffle part that faces an upstream side in the air flow direction of the gas passage is inclined with respect to an axial length direction of the gas passage so as to be capable of turning incoming air flow into swirl flow.

[0019] Preferably, the baffle part is configured as a portion of a disk shape having a larger outer diameter than a rear region of the pressure receiving part formation part.

[0020] Preferably, the baffle part is located upstream in the air flow direction from the fuel gas outlet.

[0021] Preferably, the multiple support parts are provided at equal intervals in a circumferential direction of the gas passage. The premixing device according to the present disclosure includes, as the fuel gas outlet, multiple fuel gas outlets that are located between the multiple support parts as viewed along an axial length direction of the gas passage and are provided in an array at equal intervals in the circumferential direction.

[0022] A combustion device provided by a second aspect of the present disclosure is characterized by including: a premixing device, generating a mixture in which air and fuel gas are mixed; and a burner part, receiving supply of the mixture from the premixing device and combusting the fuel gas, in which the premixing device provided by the first aspect of the present disclosure is used as the premixing device.

[0023] Other features and advantages of the present disclosure will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] [FIG. 1] FIG. 1 is a schematic explanatory diagram showing an example of a combustion device including a premixing device according to the present disclosure, and a hot water device including the combustion device. [FIG. 2] FIG. 2A is a schematic perspective view showing a main part of the premixing device shown in FIG. 1, and FIG. 2B is a front view taken along arrow IIB in FIG. 2A. [FIG. 3] FIG. 3A is a cross-sectional view taken along IIIA-IIIA in FIG. 2B, and FIG. 3B is a cross-sectional view taken along IIIB-IIIB in FIG. 2B. [FIG. 4] FIG. 4 is a cross-sectional view taken along IV-IV in FIG. 3A. [FIG. 5] FIG. 5 is an exploded schematic perspective view of FIG. 2A. [FIG. 6] FIG. 6A is a rear perspective view of the third member shown in FIG. 5, and FIG. 6B is a rear perspective view as a reference diagram with a baffle part of the third member shown in FIG. 6A omitted. [FIG. 7] FIG. 7A is a front view of the third member shown in FIG. 5 and FIG. 6A, FIG. 7B is a rear view thereof, FIG. 7C is a plan view thereof, FIG. 7D is a left side view thereof, FIG. 7E is a cross-sectional view taken along VIIE-VIIE in FIG. 7A, FIG. 7F is a cross-sectional view taken along VIIF-VIIF in FIG. 7A, and FIG. 7G is a cross-sectional view taken along VIIG-VIIG in FIG. 7A. [FIG. 8] FIG. 8 is a cross-sectional view taken along VIII-VIII in FIG. 6A. [FIG. 9] FIG. 9A and FIG. 9B are cross-sectional views showing Comparative Examples 1 and 2 (corresponding to the content of the present disclosure) in comparison with FIG. 8. [FIG. 10] FIG. 10A is a rear perspective view showing another example of the present disclosure, and FIG. 10B is a side view thereof. DESCRIPTION OF THE EMBODIMENTS

[0025] Hereinafter, preferred embodiments of the present disclosure will be specifically described with reference to the drawings.

[0026] FIG. 1 shows a hot water device WH. The hot water device WH is configured as a hot water supply device in which a heat exchanger 8 is provided in a combustion device C including a premixing device PR and a burner part B.

[0027] The burner part B is a portion for receiving supply of a mixture of fuel gas and air from the premixing device PR and combusting the fuel gas, and has a configuration in which a flame hole plate 40 including multiple flame holes 40a is arranged within a burner case 41. The fuel gas is, for example, hydrogen or hydrogen-containing gas. When the mixture is supplied into the burner case 41 from an upper opening 41a of the burner case 41, this mixture passes downward through the multiple flame holes 40a of the flame hole plate 40. Such a mixture is ignited by an ignition device (not shown). A combustion gas generated by the burner part B advances downward from a combustion region on a lower surface side of the burner part B and acts on the heat exchanger 8.

[0028] The heat exchanger 8 is for recovering heat from the combustion gas, and includes heat exchange parts 81 and 82 for sensible heat recovery and latent heat recovery located within can bodies 85 and 86. Hot and cold water supplied to a water inlet 83 is heated by the combustion gas in a process of sequentially passing through the heat exchange part 82 and the heat exchange part 81, reaches a hot water outlet 84, and is supplied to a predetermined hot water supply destination.

[0029] The premixing device PR includes a premixing device body part A, a fan 5, and a pressure adjustment valve V.

[0030] The fan 5 is for supplying air for combustion to the premixing device body part A, and is driven by a motor (not shown). The fan 5 is, for example but not limited to, a sirocco fan or a turbo fan. The specific type of the fan 5 does not matter.

[0031] The pressure adjustment valve V is provided in a position midway in a fuel gas supply path FP for supplying fuel gas to the premixing device body part A. The pressure adjustment valve V has a function of setting a secondary pressure P2 on a downstream side of the pressure adjustment valve V to a value corresponding to a signal pressure Ps input to a port 60, without being affected by fluctuations in a primary pressure P1 on an upstream side of the pressure adjustment valve V in the fuel gas supply path FP. The higher the signal pressure Ps, the larger the opening degree of a valve body 61, and the higher the fuel supply pressure toward the burner part B. By this action, it is possible to stabilize an air-fuel ratio of the mixture generated by the premixing device PR. The structure itself of the pressure adjustment valve V can be made similar to a conventionally known one, and detailed description thereof is omitted.

[0032] The port 60 is connected to a pressure receiving part 32a of the premixing device body part A via a signal pressure transmission path SP, as described later.

[0033] The premixing device body part A has a front side (upstream side (right side in FIG. 2A, FIG. 3A, FIG. 3B, and FIG. 5; the same applies hereinafter) in an air flow direction) directly connected, or indirectly connected via an appropriate connection member 98, to a discharge side of the fan 5. A gas passage 19 through which air discharged from the fan 5 flows is formed within the premixing device body part A. A fuel gas outlet 23 to be described later is also provided within the premixing device body part A, and a mixture of air and fuel gas is generated within the premixing device body part A. The premixing device body part A has a rear side (downstream side in the air flow direction) directly or indirectly connected to the upper opening 41a of the burner case 41, enabling supply of the mixture from the premixing device body part A into the burner case 41.

[0034] As shown in FIG. 2A to FIG. 5, the premixing device body part A has a configuration in which a first member 1 to a third member 3 are combined, and the gas passage 19 is formed in series inside these members. The first member 1 to the third member 3 are, for example, metal machined products or resin molded products.

[0035] The first member 1 is a tubular member. On a front part and a rear side part of the first member 1, flanges 10a and 10b for connection with other members are provided. A fuel gas introduction port 13 is provided in a peripheral wall part 12 of the first member 1, and fuel gas is supplied to this portion.

[0036] The second member 2 has a configuration in which a frame part 20 of an approximately rectangular shape is provided at a front part, and a tubular part 21 of an approximately cylindrical shape including multiple fuel gas outlets 23 is continuously provided at a rear side of the frame part 20. The second member 2 includes a flange 28 for connection with the first flange 10a.

[0037] The tubular part 21 is fitted into a front region of the first member 1. A gap 24 that communicates the fuel gas introduction port 13 to the multiple fuel gas outlets 23 is formed between the tubular part 21 and the peripheral wall part 12 of the first member 1. Thus, the fuel gas supplied to the fuel gas introduction port 13 passes through the gap 24 and reaches the multiple fuel gas outlets 23, flows out into the gas passage 19, and is mixed with air. The fuel gas supply path FP includes the fuel gas introduction port 13 and the gap 24, and the multiple fuel gas outlets 23 are a terminal end of the fuel gas supply path FP.

[0038] As well shown in FIG. 5 to FIG. 7G, the third member 3 includes an annular part 30 that is annular in front view, multiple support parts 31, a pressure receiving part formation part 32, and multiple baffle parts 33. FIG. 6B shows a configuration in which the multiple baffle parts 33 are omitted. FIG. 6B should also be referred to as appropriate for the configuration of the support part 31 and the like.

[0039] The third member 3 may be assembled to the second member 2 in a state in which the annular part 30 is fitted into an opening 25 formed in a central part of the frame part 20 of the second member 2. A space region inside the annular part 30 is part of the gas passage 19.

[0040] The pressure receiving part formation part 32 has, for example, an overall basic shape that is a nose cone shape or similar shape. The overall general shape of the pressure receiving part formation part 32 is approximately columnar and is also a truncated cone shape in which an outer diameter of a rear region gradually decreases toward the rear side. The pressure receiving part 32a of a concave opening shape is formed in a front surface part of the pressure receiving part formation part 32 that faces an upstream side in the air flow direction.

[0041] The multiple support parts 31 are a portion for arranging and supporting the pressure receiving part formation part 32 at the center of the gas passage 19, and are plate-shaped, protruding from an inner peripheral wall part (corresponding to the inner peripheral wall part of the gas passage in the present disclosure) of the annular part 30 toward a central region of the gas passage 19.

[0042] In the multiple support parts 31 and the pressure receiving part formation part 32, widths Wa and We in an axial length direction of the gas passage 19 are larger than widths Wc and Wd as viewed along the axial length direction of the gas passage 19 (refer to FIG. 7A and FIG. 7E). Thus, it is possible for the multiple support parts 31 and the pressure receiving part formation part 32 to have low resistance to air flow and high strength (strength that makes vibration less likely to occur).

[0043] In the present embodiment, as the multiple support parts 31, for example, three support parts 31 are provided at equal intervals in a circumferential direction of the gas passage 19. In contrast, as shown in FIG. 2B, the multiple fuel gas outlets 23 are located, preferably at the center, between the multiple support parts 31 as viewed along the axial length direction of the gas passage 19, and are provided in an array at equal intervals in the circumferential direction of the gas passage 19. According to such a configuration, air supplied to a front part side of the gas passage 19 passes through a region between the multiple support parts 31, thereby preventing a large amount of air from flowing in a state of being greatly biased to only a portion of the gas passage 19. With respect to such air flow, it is avoided that fuel gas is supplied and mixed in a greatly biased arrangement, which is favorable in view of sufficient mixing of air and fuel gas.

[0044] In the multiple support parts 31, the width Wb of a region close to the pressure receiving part formation part 32 is preferably larger than the width Wa of a region close to the annular part 30, and the width Wb and a front-to-rear width of the pressure receiving part formation part 32 are aligned to be approximately the same (refer to FIG. 7E). In the support part 31, the region close to the pressure receiving part formation part 32 has a cross-sectional shape in which a thickness t of a rear region gradually decreases toward the rear side, as shown in FIG. 8. This is favorable in view of suppressing generation of air vortex flow behind the support part 31 and reducing resistance of air flow in the gas passage 19.

[0045] FIG. 9A and FIG. 9B show Comparative Examples 1 and 2 in comparison with the present embodiment shown in FIG. 8. The support part 31 of Comparative Example 1 has a shape that is reversed front-to-rear from FIG. 8, and the support part 31 of Comparative Example 2 has a constant thickness at each place. According to tests and simulations by the present inventors, it is confirmed that, in the configuration of the present embodiment shown in FIG. 8, the air vortex flow generated behind the support part 31 can be reduced compared to Comparative Examples 1 and 2.

[0046] Inside each of the multiple support parts 31, a communication path 35 of a small-diameter tunnel shape having one end in communication with the pressure receiving part 32a is provided. These communication paths 35 are a portion constituting a portion of the signal pressure transmission path SP, and have the other end in communication with the inside of a concave groove 36 formed on an outer periphery of the annular part 30.

[0047] As well shown in FIG. 3A, the concave groove 36 is in communication with a port 29 provided in the second member 2, and the port 29 is connected to the port 60 of the pressure adjustment valve V via an appropriate tube (not shown). The signal pressure transmission path SP has a configuration in which the tube, port 29, concave groove 36, and multiple communication paths 35 are connected in series.

[0048] The multiple baffle parts 33 are a portion capable of turning air flow into swirl flow. The multiple baffle parts 33 are located between the multiple support parts 31 as viewed along the axial length direction of the gas passage 19, and are configured as multiple (three in the present embodiment) convex portions that protrude radially outward of the pressure receiving part formation part 32 from a rear region of the pressure receiving part formation part 32.

[0049] As shown in FIG. 7G, a front surface part 33a of each baffle part 33 is an inclined surface part inclined with respect to the axial length direction of the gas passage 19, and thus the air flow that arrives at the front surface part 33a becomes swirl flow. In FIG. 7G, the front surface part 33a has a curved surface shape having an appropriate curvature R. However, it is also possible that the front surface part 33a has, for example, a planar shape, instead of a curved surface shape.

[0050] Each baffle part 33 is located downstream in the air flow direction from the pressure receiving part 32a and upstream in the air flow direction from the fuel gas outlet 23.

[0051] Next, the action and effect of the combustion device C including the premixing device PR and the hot water device WH will be described.

[0052] First, in FIG. 1, when the combustion device C is driven, air is discharged from the fan 5 toward the gas passage 19 of the premixing device body part A. On the other hand, fuel gas is supplied toward the premixing device body part A via the fuel gas supply path FP and flows out from multiple fuel gas outlets 23 into the gas passage 19. Thus, since a mixture of air and fuel gas is generated and supplied to the burner part B, it is possible to combust the fuel gas in the burner part B. During such an operation, at the pressure receiving part 32a of the premixing device body part A, air pressure of the air flowing through the gas passage 19 is received, and this air pressure is transmitted as the signal pressure Ps to the port 60 of the pressure adjustment valve V via the signal pressure transmission path SP. Then, the pressure adjustment valve V controls a secondary pressure of the fuel gas to a pressure corresponding to the aforementioned air pressure (signal pressure Ps).

[0053] Here, since the pressure receiving part formation part 32 is supported by multiple support parts 31, it is possible to improve support strength of the pressure receiving part formation part 32 and prevent the pressure receiving part formation part 32 from easily vibrating due to the influence of air flow. Since each support part 31 has a large front-to-rear width, the support strength is improved and vibration is suppressed, which is relatively favorable. If the pressure receiving part formation part 32 vibrates, in the case where the air pressure received at the pressure receiving part 32a is used as a signal pressure of the pressure adjustment valve V, this signal pressure may include an error caused by vibration, which is not favorable. In contrast, according to the present embodiment, it is possible to suitably suppress such defects. That is, according to the present embodiment, it is possible to make the signal pressure accurate without including an error caused by vibration, and to suitably and highly precisely stabilize an air-fuel ratio.

[0054] On the other hand, when air advances to the position of the baffle part 33, the air flow becomes swirl flow. Accordingly, stirring and mixing of air and fuel gas are facilitated, and the combustibility of the mixed gas can be improved.

[0055] In the present embodiment, the premixing device body part A is provided on the discharge side of the fan 5, and no stirring occurs in the process during which the mixture passes through the fan 5. However, it is possible to supply sufficiently stirred and mixed mixture to the burner part B by the effect of facilitating stirring and mixing of the baffle part 33. Accordingly, in the present embodiment, disadvantages due to the provision of the premixing device body part A on the discharge side of the fan 5 can be prevented from occurring. As described above, since the premixing device body part A is provided on the discharge side of the fan 5, it is possible to enhance safety when hydrogen or hydrogen-containing gas that is prone to ignition is used as fuel gas.

[0056] The communication path 35 is provided inside each of the multiple support parts 31, and multiple communication paths 35 are provided to connect the pressure receiving part 32a and the concave groove 36. Hence, even if clogging occurs in any one of the multiple communication paths 35, a signal pressure can be transmitted using any other communication path 35. Accordingly, the reliability of fuel gas supply pressure control using the signal pressure Ps can be enhanced. Since the multiple communication paths 35 constituting the signal pressure transmission path SP are provided inside the multiple support parts 31, these communication paths 35 are prevented from becoming a largely bulky portion, which is favorable in view of simplification and weight reduction of the overall configuration of the premixing device body part A. Furthermore, it is possible to prevent defects such as that the multiple communication paths 35 obstruct air flow in the gas passage 19.

[0057] Since the baffle part 33 is located downstream in the air flow direction from the pressure receiving part 32a, swirl flow is prevented from acting on the pressure receiving part 32a, which is favorable in view of obtaining accurate air pressure (signal pressure Ps). On the other hand, since the baffle part 33 is located upstream in the air flow direction from the multiple fuel gas outlets 23, it is possible to directly flow fuel gas from the fuel gas outlet 23 into the swirl flow of air generated using the baffle part 33. Accordingly, stirring and mixing of the mixture can further be facilitated.

[0058] As described above, the baffle part 33 generates swirl flow of air, and the front surface part 33a of the baffle part 33 is formed as an inclined surface part. Accordingly, it is also possible to prevent the resistance of air flow in the gas passage 19 from becoming excessively large due to the presence of the baffle part 33. Furthermore, since the baffle part 33 is located between the multiple support parts 31 and provided at equal intervals in the circumferential direction of the gas passage 19, it is also possible to generate an action that air collides with the front surface part 33a of the baffle part 33 in a well-balanced manner.

[0059] FIG. 10A and FIG. 10B show another embodiment of the present disclosure. In FIG. 10A and FIG. 10B, elements that are the same as or similar to those in the aforementioned embodiment are assigned the same reference numerals as in the aforementioned embodiment, and duplicate descriptions are omitted.

[0060] In a third member 3A shown in FIG. 10A and FIG. 10B, the baffle part 33A is formed in a disk shape. The baffle part 33A has a larger outer diameter than the rear region of the pressure receiving part formation part 32 and is connected to a rear end of the multiple support parts 31.

[0061] According to the present embodiment, it is possible to generate turbulent flow of air by air colliding with a front surface part 33b of the baffle part 33A. Using this turbulent flow, it is possible to facilitate stirring and mixing of air and fuel gas.

[0062] As understood from the present embodiment, in the present disclosure, instead of or in addition to a configuration in which swirl flow is generated using a baffle part, it is also possible to adopt a configuration in which turbulent flow is generated as non-swirl flow that facilitates stirring and mixing of air and fuel gas.

[0063] The present disclosure is not limited to the content of the above-described embodiments. The specific configurations of each part of the premixing device and combustion device according to the present disclosure can be variously modified in design within the intended scope of the present disclosure.

[0064] The pressure receiving part only needs to have a concave opening shape capable of receiving air pressure in a gas passage, and is not limited to specific shape, size or the like. The pressure receiving part formation part only needs to include the pressure receiving part, and the overall shape of the pressure receiving part formation part is not limited to a nose cone shape.

[0065] The multiple support parts that support the pressure receiving part formation part only need to be provided at intervals in the circumferential direction of the gas passage, and the number thereof is not limited to three. A configuration in which only two support parts are provided, or a configuration in which four or more support parts are provided can be adopted.

[0066] The communication path does not necessarily have to be provided in all of the multiple support parts.

[0067] As already described, the baffle part only needs to enable the generation of swirl flow or turbulent flow capable of facilitating stirring and mixing of air and fuel gas. Accordingly, the specific shape of the baffle part is not limited. The number or arrangement of the baffle part can also be variously modified. In the above-described embodiments, the baffle part is provided so as to extend across both the support part and the pressure receiving part formation part. However, instead of the above, for example, a configuration may be adopted in which the baffle part is provided on one of the support part and the pressure receiving part formation part.

[0068] The premixing device according to the present disclosure is suitable in the case of using hydrogen or hydrogen-containing gas as fuel gas, but is not limited thereto, and other types of gas can be used.

Examples

Embodiment Construction

[0025]Hereinafter, preferred embodiments of the present disclosure will be specifically described with reference to the drawings.

[0026]FIG. 1 shows a hot water device WH. The hot water device WH is configured as a hot water supply device in which a heat exchanger 8 is provided in a combustion device C including a premixing device PR and a burner part B.

[0027]The burner part B is a portion for receiving supply of a mixture of fuel gas and air from the premixing device PR and combusting the fuel gas, and has a configuration in which a flame hole plate 40 including multiple flame holes 40a is arranged within a burner case 41. The fuel gas is, for example, hydrogen or hydrogen-containing gas. When the mixture is supplied into the burner case 41 from an upper opening 41a of the burner case 41, this mixture passes downward through the multiple flame holes 40a of the flame hole plate 40. Such a mixture is ignited by an ignition device (not shown). A combustion gas generated by the burner p...

Technical Field

[0001] The present disclosure relates to a premixing device and a combustion device including the same.

[0002] Here, "premixing" is processing for mixing air and fuel gas in advance and generating a combustible mixture for the purpose of performing premixing combustion.Related Art

[0003] As an example of a premixing device, there is one described in Patent Document 1.

[0004] In the premixing device described in Patent Document 1, a premixing device body part is connected to an intake side of a fan. The premixing device body part has a configuration in which a gas passage through which air flows by driving of the fan is formed inside, and a fuel gas outlet is provided facing the gas passage. Thus, it is possible to generate a mixture of air and fuel gas. The premixing device body part includes a probe for sensing air pressure within the gas passage. A tip of the probe is a pressure receiving part of a concave opening shape that receives air pressure. The air pressure received at the pressure receiving part is used as a signal pressure of a pressure adjustment valve provided in a fuel gas supply path.

[0005] According to such a configuration, it is possible to control a fuel gas supply pressure as a secondary pressure of the pressure adjustment valve to a pressure corresponding to the air pressure in the gas passage, and to stabilize an air-fuel ratio.

[0006] However, in the aforementioned conventional technology, there is still room for improvement as described below.

[0007] Firstly, the probe described in Patent Document 1 is a single pipe body having an approximately L-shape in side view. The probe is attached in a manner (cantilever support manner) in which a portion of the probe penetrates a peripheral wall part of the gas passage. Hence, the pressure receiving part located at the tip of the probe is likely to vibrate under the influence of air flow. Here, when the pressure receiving part vibrates, in the case where the air pressure received at the pressure receiving part is utilized as the signal pressure of the pressure adjustment valve, the signal pressure becomes inappropriate including an error caused by vibration. Accordingly, it is difficult to perform highly precise control for stabilizing the air-fuel ratio.

[0008] Secondly, it is desired that a mixture (combustible mixture) generated in the premixing device be one in which air and fuel gas are sufficiently stirred and mixed. Here, in Patent Document 1, since the premixing device body part is provided on the intake side of the fan, the mixture of air and fuel gas is sufficiently stirred and mixed at a stage of passing through the fan. However, in Patent Document 1, in the case where the premixing device body part is provided on a discharge side of the fan and the mixture does not pass through the fan, it is difficult to actively stir and mix air and fuel gas. As a result, there is a risk that the combustibility of the mixture may be reduced.

[0009] As one implementation means for realizing a low-carbon society, it is conceivable to use hydrogen or hydrogen-containing gas as fuel gas. However, since the hydrogen or hydrogen-containing gas is prone to ignition, in the case where fuel gas is hydrogen or hydrogen-containing gas, it is desired to arrange the premixing device body part (mixing part of air and fuel gas) on the discharge side of the fan from the viewpoint of safety. In contrast, the premixing device of Patent Document 1 is not suitable for use in such a manner.Prior Art DocumentsPatent Documents

[0010] Patent Document 1: Japanese Patent No. 6673863 Patent Document 2: Japanese Patent Laid-Open No. 2010-107174 Patent Document 3: Japanese Publication of Examined Patent Application No. S58-43655 SUMMARY OF INVENTIONTechnical Problem

[0011] An object of the present disclosure is to provide a premixing device and a combustion device including the same, in which the premixing device enables highly precise control for stabilizing an air-fuel ratio so that air pressure of a gas passage can be utilized as an accurate signal pressure for a pressure adjustment valve of fuel gas, and also enables sufficient stirring and mixing of air and fuel gas even if a premixing device body part is connected to a discharge side of a fan. Solution to Problem

[0012] In order to solve the above problem, the present disclosure employs the following technical means.

[0013] The premixing device provided by a first aspect of the present disclosure is characterized by including: a fan; a premixing device body part, connected to a discharge side of the fan, having formed therein a gas passage through which air flows by driving of the fan, and provided with a fuel gas outlet at a terminal end of a fuel gas supply path in a manner enabling fuel gas to flow into the gas passage and be mixed with the air; a pressure adjustment valve, provided in the fuel gas supply path and controlling a fuel gas supply pressure to a pressure corresponding to a signal pressure; multiple support parts, respectively provided to protrude from an inner peripheral wall part of the gas passage toward a central region of the gas passage, and arranged at intervals from each other in a circumferential direction of the gas passage; a pressure receiving part formation part, supported by the multiple support parts and provided in the gas passage, including a pressure receiving part of a concave opening shape that receives air pressure at a position upstream in an air flow direction from the fuel gas outlet; a communication path, provided inside at least one of the multiple support parts and communicating with the pressure receiving part; a signal pressure transmission path, configured to include the communication path, and transmitting, as the signal pressure, the air pressure received at the pressure receiving part, to the pressure adjustment valve; and a baffle part, provided at a portion downstream in the air flow direction from the pressure receiving part and capable of turning incoming air flow into swirl flow or turbulent flow.

[0014] Preferably, the premixing device according to the present disclosure includes, as the communication path, multiple communication paths provided inside each of the multiple support parts.

[0015] Preferably, in the pressure receiving part formation part and the multiple support parts, a width in an axial length direction of the gas passage is larger than a width as viewed along an axial length direction of the gas passage.

[0016] Preferably, the pressure receiving part is formed in an upstream side portion in the air flow direction of the pressure receiving part formation part; the baffle part is provided in a downstream side portion in the air flow direction of the multiple support parts and / or the pressure receiving part formation part.

[0017] Preferably, the baffle part is configured as multiple convex portions that are located between the multiple support parts as viewed along an axial length direction of the gas passage and protrude radially outward of the pressure receiving part formation part from the pressure receiving part formation part.

[0018] Preferably, a portion of the baffle part that faces an upstream side in the air flow direction of the gas passage is inclined with respect to an axial length direction of the gas passage so as to be capable of turning incoming air flow into swirl flow.

[0019] Preferably, the baffle part is configured as a portion of a disk shape having a larger outer diameter than a rear region of the pressure receiving part formation part.

[0020] Preferably, the baffle part is located upstream in the air flow direction from the fuel gas outlet.

[0021] Preferably, the multiple support parts are provided at equal intervals in a circumferential direction of the gas passage. The premixing device according to the present disclosure includes, as the fuel gas outlet, multiple fuel gas outlets that are located between the multiple support parts as viewed along an axial length direction of the gas passage and are provided in an array at equal intervals in the circumferential direction.

[0022] A combustion device provided by a second aspect of the present disclosure is characterized by including: a premixing device, generating a mixture in which air and fuel gas are mixed; and a burner part, receiving supply of the mixture from the premixing device and combusting the fuel gas, in which the premixing device provided by the first aspect of the present disclosure is used as the premixing device.

[0023] Other features and advantages of the present disclosure will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] [FIG. 1] FIG. 1 is a schematic explanatory diagram showing an example of a combustion device including a premixing device according to the present disclosure, and a hot water device including the combustion device. [FIG. 2] FIG. 2A is a schematic perspective view showing a main part of the premixing device shown in FIG. 1, and FIG. 2B is a front view taken along arrow IIB in FIG. 2A. [FIG. 3] FIG. 3A is a cross-sectional view taken along IIIA-IIIA in FIG. 2B, and FIG. 3B is a cross-sectional view taken along IIIB-IIIB in FIG. 2B. [FIG. 4] FIG. 4 is a cross-sectional view taken along IV-IV in FIG. 3A. [FIG. 5] FIG. 5 is an exploded schematic perspective view of FIG. 2A. [FIG. 6] FIG. 6A is a rear perspective view of the third member shown in FIG. 5, and FIG. 6B is a rear perspective view as a reference diagram with a baffle part of the third member shown in FIG. 6A omitted. [FIG. 7] FIG. 7A is a front view of the third member shown in FIG. 5 and FIG. 6A, FIG. 7B is a rear view thereof, FIG. 7C is a plan view thereof, FIG. 7D is a left side view thereof, FIG. 7E is a cross-sectional view taken along VIIE-VIIE in FIG. 7A, FIG. 7F is a cross-sectional view taken along VIIF-VIIF in FIG. 7A, and FIG. 7G is a cross-sectional view taken along VIIG-VIIG in FIG. 7A. [FIG. 8] FIG. 8 is a cross-sectional view taken along VIII-VIII in FIG. 6A. [FIG. 9] FIG. 9A and FIG. 9B are cross-sectional views showing Comparative Examples 1 and 2 (corresponding to the content of the present disclosure) in comparison with FIG. 8. [FIG. 10] FIG. 10A is a rear perspective view showing another example of the present disclosure, and FIG. 10B is a side view thereof. DESCRIPTION OF THE EMBODIMENTS

[0025] Hereinafter, preferred embodiments of the present disclosure will be specifically described with reference to the drawings.

[0026] FIG. 1 shows a hot water device WH. The hot water device WH is configured as a hot water supply device in which a heat exchanger 8 is provided in a combustion device C including a premixing device PR and a burner part B.

[0027] The burner part B is a portion for receiving supply of a mixture of fuel gas and air from the premixing device PR and combusting the fuel gas, and has a configuration in which a flame hole plate 40 including multiple flame holes 40a is arranged within a burner case 41. The fuel gas is, for example, hydrogen or hydrogen-containing gas. When the mixture is supplied into the burner case 41 from an upper opening 41a of the burner case 41, this mixture passes downward through the multiple flame holes 40a of the flame hole plate 40. Such a mixture is ignited by an ignition device (not shown). A combustion gas generated by the burner part B advances downward from a combustion region on a lower surface side of the burner part B and acts on the heat exchanger 8.

[0028] The heat exchanger 8 is for recovering heat from the combustion gas, and includes heat exchange parts 81 and 82 for sensible heat recovery and latent heat recovery located within can bodies 85 and 86. Hot and cold water supplied to a water inlet 83 is heated by the combustion gas in a process of sequentially passing through the heat exchange part 82 and the heat exchange part 81, reaches a hot water outlet 84, and is supplied to a predetermined hot water supply destination.

[0029] The premixing device PR includes a premixing device body part A, a fan 5, and a pressure adjustment valve V.

[0030] The fan 5 is for supplying air for combustion to the premixing device body part A, and is driven by a motor (not shown). The fan 5 is, for example but not limited to, a sirocco fan or a turbo fan. The specific type of the fan 5 does not matter.

[0031] The pressure adjustment valve V is provided in a position midway in a fuel gas supply path FP for supplying fuel gas to the premixing device body part A. The pressure adjustment valve V has a function of setting a secondary pressure P2 on a downstream side of the pressure adjustment valve V to a value corresponding to a signal pressure Ps input to a port 60, without being affected by fluctuations in a primary pressure P1 on an upstream side of the pressure adjustment valve V in the fuel gas supply path FP. The higher the signal pressure Ps, the larger the opening degree of a valve body 61, and the higher the fuel supply pressure toward the burner part B. By this action, it is possible to stabilize an air-fuel ratio of the mixture generated by the premixing device PR. The structure itself of the pressure adjustment valve V can be made similar to a conventionally known one, and detailed description thereof is omitted.

[0032] The port 60 is connected to a pressure receiving part 32a of the premixing device body part A via a signal pressure transmission path SP, as described later.

[0033] The premixing device body part A has a front side (upstream side (right side in FIG. 2A, FIG. 3A, FIG. 3B, and FIG. 5; the same applies hereinafter) in an air flow direction) directly connected, or indirectly connected via an appropriate connection member 98, to a discharge side of the fan 5. A gas passage 19 through which air discharged from the fan 5 flows is formed within the premixing device body part A. A fuel gas outlet 23 to be described later is also provided within the premixing device body part A, and a mixture of air and fuel gas is generated within the premixing device body part A. The premixing device body part A has a rear side (downstream side in the air flow direction) directly or indirectly connected to the upper opening 41a of the burner case 41, enabling supply of the mixture from the premixing device body part A into the burner case 41.

[0034] As shown in FIG. 2A to FIG. 5, the premixing device body part A has a configuration in which a first member 1 to a third member 3 are combined, and the gas passage 19 is formed in series inside these members. The first member 1 to the third member 3 are, for example, metal machined products or resin molded products.

[0035] The first member 1 is a tubular member. On a front part and a rear side part of the first member 1, flanges 10a and 10b for connection with other members are provided. A fuel gas introduction port 13 is provided in a peripheral wall part 12 of the first member 1, and fuel gas is supplied to this portion.

[0036] The second member 2 has a configuration in which a frame part 20 of an approximately rectangular shape is provided at a front part, and a tubular part 21 of an approximately cylindrical shape including multiple fuel gas outlets 23 is continuously provided at a rear side of the frame part 20. The second member 2 includes a flange 28 for connection with the first flange 10a.

[0037] The tubular part 21 is fitted into a front region of the first member 1. A gap 24 that communicates the fuel gas introduction port 13 to the multiple fuel gas outlets 23 is formed between the tubular part 21 and the peripheral wall part 12 of the first member 1. Thus, the fuel gas supplied to the fuel gas introduction port 13 passes through the gap 24 and reaches the multiple fuel gas outlets 23, flows out into the gas passage 19, and is mixed with air. The fuel gas supply path FP includes the fuel gas introduction port 13 and the gap 24, and the multiple fuel gas outlets 23 are a terminal end of the fuel gas supply path FP.

[0038] As well shown in FIG. 5 to FIG. 7G, the third member 3 includes an annular part 30 that is annular in front view, multiple support parts 31, a pressure receiving part formation part 32, and multiple baffle parts 33. FIG. 6B shows a configuration in which the multiple baffle parts 33 are omitted. FIG. 6B should also be referred to as appropriate for the configuration of the support part 31 and the like.

[0039] The third member 3 may be assembled to the second member 2 in a state in which the annular part 30 is fitted into an opening 25 formed in a central part of the frame part 20 of the second member 2. A space region inside the annular part 30 is part of the gas passage 19.

[0040] The pressure receiving part formation part 32 has, for example, an overall basic shape that is a nose cone shape or similar shape. The overall general shape of the pressure receiving part formation part 32 is approximately columnar and is also a truncated cone shape in which an outer diameter of a rear region gradually decreases toward the rear side. The pressure receiving part 32a of a concave opening shape is formed in a front surface part of the pressure receiving part formation part 32 that faces an upstream side in the air flow direction.

[0041] The multiple support parts 31 are a portion for arranging and supporting the pressure receiving part formation part 32 at the center of the gas passage 19, and are plate-shaped, protruding from an inner peripheral wall part (corresponding to the inner peripheral wall part of the gas passage in the present disclosure) of the annular part 30 toward a central region of the gas passage 19.

[0042] In the multiple support parts 31 and the pressure receiving part formation part 32, widths Wa and We in an axial length direction of the gas passage 19 are larger than widths Wc and Wd as viewed along the axial length direction of the gas passage 19 (refer to FIG. 7A and FIG. 7E). Thus, it is possible for the multiple support parts 31 and the pressure receiving part formation part 32 to have low resistance to air flow and high strength (strength that makes vibration less likely to occur).

[0043] In the present embodiment, as the multiple support parts 31, for example, three support parts 31 are provided at equal intervals in a circumferential direction of the gas passage 19. In contrast, as shown in FIG. 2B, the multiple fuel gas outlets 23 are located, preferably at the center, between the multiple support parts 31 as viewed along the axial length direction of the gas passage 19, and are provided in an array at equal intervals in the circumferential direction of the gas passage 19. According to such a configuration, air supplied to a front part side of the gas passage 19 passes through a region between the multiple support parts 31, thereby preventing a large amount of air from flowing in a state of being greatly biased to only a portion of the gas passage 19. With respect to such air flow, it is avoided that fuel gas is supplied and mixed in a greatly biased arrangement, which is favorable in view of sufficient mixing of air and fuel gas.

[0044] In the multiple support parts 31, the width Wb of a region close to the pressure receiving part formation part 32 is preferably larger than the width Wa of a region close to the annular part 30, and the width Wb and a front-to-rear width of the pressure receiving part formation part 32 are aligned to be approximately the same (refer to FIG. 7E). In the support part 31, the region close to the pressure receiving part formation part 32 has a cross-sectional shape in which a thickness t of a rear region gradually decreases toward the rear side, as shown in FIG. 8. This is favorable in view of suppressing generation of air vortex flow behind the support part 31 and reducing resistance of air flow in the gas passage 19.

[0045] FIG. 9A and FIG. 9B show Comparative Examples 1 and 2 in comparison with the present embodiment shown in FIG. 8. The support part 31 of Comparative Example 1 has a shape that is reversed front-to-rear from FIG. 8, and the support part 31 of Comparative Example 2 has a constant thickness at each place. According to tests and simulations by the present inventors, it is confirmed that, in the configuration of the present embodiment shown in FIG. 8, the air vortex flow generated behind the support part 31 can be reduced compared to Comparative Examples 1 and 2.

[0046] Inside each of the multiple support parts 31, a communication path 35 of a small-diameter tunnel shape having one end in communication with the pressure receiving part 32a is provided. These communication paths 35 are a portion constituting a portion of the signal pressure transmission path SP, and have the other end in communication with the inside of a concave groove 36 formed on an outer periphery of the annular part 30.

[0047] As well shown in FIG. 3A, the concave groove 36 is in communication with a port 29 provided in the second member 2, and the port 29 is connected to the port 60 of the pressure adjustment valve V via an appropriate tube (not shown). The signal pressure transmission path SP has a configuration in which the tube, port 29, concave groove 36, and multiple communication paths 35 are connected in series.

[0048] The multiple baffle parts 33 are a portion capable of turning air flow into swirl flow. The multiple baffle parts 33 are located between the multiple support parts 31 as viewed along the axial length direction of the gas passage 19, and are configured as multiple (three in the present embodiment) convex portions that protrude radially outward of the pressure receiving part formation part 32 from a rear region of the pressure receiving part formation part 32.

[0049] As shown in FIG. 7G, a front surface part 33a of each baffle part 33 is an inclined surface part inclined with respect to the axial length direction of the gas passage 19, and thus the air flow that arrives at the front surface part 33a becomes swirl flow. In FIG. 7G, the front surface part 33a has a curved surface shape having an appropriate curvature R. However, it is also possible that the front surface part 33a has, for example, a planar shape, instead of a curved surface shape.

[0050] Each baffle part 33 is located downstream in the air flow direction from the pressure receiving part 32a and upstream in the air flow direction from the fuel gas outlet 23.

[0051] Next, the action and effect of the combustion device C including the premixing device PR and the hot water device WH will be described.

[0052] First, in FIG. 1, when the combustion device C is driven, air is discharged from the fan 5 toward the gas passage 19 of the premixing device body part A. On the other hand, fuel gas is supplied toward the premixing device body part A via the fuel gas supply path FP and flows out from multiple fuel gas outlets 23 into the gas passage 19. Thus, since a mixture of air and fuel gas is generated and supplied to the burner part B, it is possible to combust the fuel gas in the burner part B. During such an operation, at the pressure receiving part 32a of the premixing device body part A, air pressure of the air flowing through the gas passage 19 is received, and this air pressure is transmitted as the signal pressure Ps to the port 60 of the pressure adjustment valve V via the signal pressure transmission path SP. Then, the pressure adjustment valve V controls a secondary pressure of the fuel gas to a pressure corresponding to the aforementioned air pressure (signal pressure Ps).

[0053] Here, since the pressure receiving part formation part 32 is supported by multiple support parts 31, it is possible to improve support strength of the pressure receiving part formation part 32 and prevent the pressure receiving part formation part 32 from easily vibrating due to the influence of air flow. Since each support part 31 has a large front-to-rear width, the support strength is improved and vibration is suppressed, which is relatively favorable. If the pressure receiving part formation part 32 vibrates, in the case where the air pressure received at the pressure receiving part 32a is used as a signal pressure of the pressure adjustment valve V, this signal pressure may include an error caused by vibration, which is not favorable. In contrast, according to the present embodiment, it is possible to suitably suppress such defects. That is, according to the present embodiment, it is possible to make the signal pressure accurate without including an error caused by vibration, and to suitably and highly precisely stabilize an air-fuel ratio.

[0054] On the other hand, when air advances to the position of the baffle part 33, the air flow becomes swirl flow. Accordingly, stirring and mixing of air and fuel gas are facilitated, and the combustibility of the mixed gas can be improved.

[0055] In the present embodiment, the premixing device body part A is provided on the discharge side of the fan 5, and no stirring occurs in the process during which the mixture passes through the fan 5. However, it is possible to supply sufficiently stirred and mixed mixture to the burner part B by the effect of facilitating stirring and mixing of the baffle part 33. Accordingly, in the present embodiment, disadvantages due to the provision of the premixing device body part A on the discharge side of the fan 5 can be prevented from occurring. As described above, since the premixing device body part A is provided on the discharge side of the fan 5, it is possible to enhance safety when hydrogen or hydrogen-containing gas that is prone to ignition is used as fuel gas.

[0056] The communication path 35 is provided inside each of the multiple support parts 31, and multiple communication paths 35 are provided to connect the pressure receiving part 32a and the concave groove 36. Hence, even if clogging occurs in any one of the multiple communication paths 35, a signal pressure can be transmitted using any other communication path 35. Accordingly, the reliability of fuel gas supply pressure control using the signal pressure Ps can be enhanced. Since the multiple communication paths 35 constituting the signal pressure transmission path SP are provided inside the multiple support parts 31, these communication paths 35 are prevented from becoming a largely bulky portion, which is favorable in view of simplification and weight reduction of the overall configuration of the premixing device body part A. Furthermore, it is possible to prevent defects such as that the multiple communication paths 35 obstruct air flow in the gas passage 19.

[0057] Since the baffle part 33 is located downstream in the air flow direction from the pressure receiving part 32a, swirl flow is prevented from acting on the pressure receiving part 32a, which is favorable in view of obtaining accurate air pressure (signal pressure Ps). On the other hand, since the baffle part 33 is located upstream in the air flow direction from the multiple fuel gas outlets 23, it is possible to directly flow fuel gas from the fuel gas outlet 23 into the swirl flow of air generated using the baffle part 33. Accordingly, stirring and mixing of the mixture can further be facilitated.

[0058] As described above, the baffle part 33 generates swirl flow of air, and the front surface part 33a of the baffle part 33 is formed as an inclined surface part. Accordingly, it is also possible to prevent the resistance of air flow in the gas passage 19 from becoming excessively large due to the presence of the baffle part 33. Furthermore, since the baffle part 33 is located between the multiple support parts 31 and provided at equal intervals in the circumferential direction of the gas passage 19, it is also possible to generate an action that air collides with the front surface part 33a of the baffle part 33 in a well-balanced manner.

[0059] FIG. 10A and FIG. 10B show another embodiment of the present disclosure. In FIG. 10A and FIG. 10B, elements that are the same as or similar to those in the aforementioned embodiment are assigned the same reference numerals as in the aforementioned embodiment, and duplicate descriptions are omitted.

[0060] In a third member 3A shown in FIG. 10A and FIG. 10B, the baffle part 33A is formed in a disk shape. The baffle part 33A has a larger outer diameter than the rear region of the pressure receiving part formation part 32 and is connected to a rear end of the multiple support parts 31.

[0061] According to the present embodiment, it is possible to generate turbulent flow of air by air colliding with a front surface part 33b of the baffle part 33A. Using this turbulent flow, it is possible to facilitate stirring and mixing of air and fuel gas.

[0062] As understood from the present embodiment, in the present disclosure, instead of or in addition to a configuration in which swirl flow is generated using a baffle part, it is also possible to adopt a configuration in which turbulent flow is generated as non-swirl flow that facilitates stirring and mixing of air and fuel gas.

[0063] The present disclosure is not limited to the content of the above-described embodiments. The specific configurations of each part of the premixing device and combustion device according to the present disclosure can be variously modified in design within the intended scope of the present disclosure.

[0064] The pressure receiving part only needs to have a concave opening shape capable of receiving air pressure in a gas passage, and is not limited to specific shape, size or the like. The pressure receiving part formation part only needs to include the pressure receiving part, and the overall shape of the pressure receiving part formation part is not limited to a nose cone shape.

[0065] The multiple support parts that support the pressure receiving part formation part only need to be provided at intervals in the circumferential direction of the gas passage, and the number thereof is not limited to three. A configuration in which only two support parts are provided, or a configuration in which four or more support parts are provided can be adopted.

[0066] The communication path does not necessarily have to be provided in all of the multiple support parts.

[0067] As already described, the baffle part only needs to enable the generation of swirl flow or turbulent flow capable of facilitating stirring and mixing of air and fuel gas. Accordingly, the specific shape of the baffle part is not limited. The number or arrangement of the baffle part can also be variously modified. In the above-described embodiments, the baffle part is provided so as to extend across both the support part and the pressure receiving part formation part. However, instead of the above, for example, a configuration may be adopted in which the baffle part is provided on one of the support part and the pressure receiving part formation part.

[0068] The premixing device according to the present disclosure is suitable in the case of using hydrogen or hydrogen-containing gas as fuel gas, but is not limited thereto, and other types of gas can be used.

Examples

Embodiment Construction

[0025]Hereinafter, preferred embodiments of the present disclosure will be specifically described with reference to the drawings.

[0026]FIG. 1 shows a hot water device WH. The hot water device WH is configured as a hot water supply device in which a heat exchanger 8 is provided in a combustion device C including a premixing device PR and a burner part B.

[0027]The burner part B is a portion for receiving supply of a mixture of fuel gas and air from the premixing device PR and combusting the fuel gas, and has a configuration in which a flame hole plate 40 including multiple flame holes 40a is arranged within a burner case 41. The fuel gas is, for example, hydrogen or hydrogen-containing gas. When the mixture is supplied into the burner case 41 from an upper opening 41a of the burner case 41, this mixture passes downward through the multiple flame holes 40a of the flame hole plate 40. Such a mixture is ignited by an ignition device (not shown). A combustion gas generated by the burner p...

Claims

1. A premixing device, <b>characterized by comprising: a fan; a premixing device body part, connected to a discharge side of the fan, having formed therein a gas passage through which air flows by driving of the fan, and provided with a fuel gas outlet at a terminal end of a fuel gas supply path in a manner enabling fuel gas to flow into the gas passage and be mixed with the air; a pressure adjustment valve, provided in the fuel gas supply path and controlling a fuel gas supply pressure to a pressure corresponding to a signal pressure; a plurality of support parts, respectively provided to protrude from an inner peripheral wall part of the gas passage toward a central region of the gas passage, and arranged at intervals from each other in a circumferential direction of the gas passage; a pressure receiving part formation part, supported by the plurality of support parts and provided in the gas passage, comprising a pressure receiving part of a concave opening shape that receives air pressure at a position upstream in an air flow direction from the fuel gas outlet; a communication path, provided inside at least one of the plurality of support parts and communicating with the pressure receiving part; a signal pressure transmission path, configured to comprise the communication path, and transmitting, as the signal pressure, the air pressure received at the pressure receiving part, to the pressure adjustment valve; and a baffle part, provided at a portion downstream in the air flow direction from the pressure receiving part and capable of turning incoming air flow into swirl flow or turbulent flow.

2. The premixing device according to claim 1, comprising: as the communication path, a plurality of communication paths provided inside each of the plurality of support parts.

3. The premixing device according to claim 1, wherein, in the pressure receiving part formation part and the plurality of support parts, a width in an axial length direction of the gas passage is larger than a width as viewed along an axial length direction of the gas passage.

4. The premixing device according to claim 1, wherein the pressure receiving part is formed in an upstream side portion in the air flow direction of the pressure receiving part formation part; and the baffle part is provided in a downstream side portion in the air flow direction of the plurality of support parts and / or the pressure receiving part formation part.

5. The premixing device according to claim 4, wherein the baffle part is configured as a plurality of convex portions that are located between the plurality of support parts as viewed along an axial length direction of the gas passage and protrude radially outward of the pressure receiving part formation part from the pressure receiving part formation part.

6. The premixing device according to claim 5, wherein a portion of the baffle part that faces an upstream side in the air flow direction of the gas passage is inclined with respect to an axial length direction of the gas passage so as to be capable of turning incoming air flow into swirl flow.

7. The premixing device according to claim 4, wherein the baffle part is configured as a portion of a disk shape having a larger outer diameter than a rear region of the pressure receiving part formation part.

8. The premixing device according to claim 1, wherein the baffle part is located upstream in the air flow direction from the fuel gas outlet.

9. The premixing device according to claim 1, wherein the plurality of support parts are provided at equal intervals in a circumferential direction of the gas passage; and, as the fuel gas outlet, a plurality of fuel gas outlets are provided that are located between the plurality of support parts as viewed along an axial length direction of the gas passage and are provided in an array at equal intervals in the circumferential direction.

10. A combustion device, <b>characterized by comprising: a premixing device, generating a mixture in which air and fuel gas are mixed; and a burner part, receiving supply of the mixture from the premixing device and combusting the fuel gas, wherein the premixing device according to any one of claims 1 to 9 is used as the premixing device.

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