JP2020020509A - Forced air supply type combustion device - Google Patents

Abstract

To detect occurrence of blocking of a fin of a heat exchanger in a forced air supply type combustion device including: a combustion chamber for burning air-fuel mixture jetted out from a burner; a combustion gas passage in which combustion gas generated through combustion in the combustion chamber flows; the heat exchanger disposed in the combustion gas passage; a combustion fan for forcedly supplying air necessary for combustion; and an air passage that has a downstream end connected to a portion of the combustion gas passage downstream of the heat exchanger and in which air flows bypassing the combustion chamber.SOLUTION: A forced air supply type combustion device includes: a bypass hole 12 for communicating part of a combustion chamber 5 with an air passage 11; and temperature detection means 13 provided at a portion of the air passage 11 on the downstream side of the bypass hole 12. Whether or not a fin of the heat exchanger is blocked is determined based on a detection temperature obtained by the temperature detection means 13.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a burner, a combustion chamber for burning an air-fuel mixture ejected from the burner, a combustion gas path in which combustion gas generated by combustion in the combustion chamber flows, a heat exchanger disposed in the combustion gas path, and a combustion chamber. And a combustion fan for forcibly supplying necessary air to the combustion apparatus.

  2. Description of the Related Art Conventionally, as this type of combustion device, there is known a combustion device including an air passage that has a downstream end connected to a portion of a combustion gas path downstream of a heat exchanger and that bypasses a combustion chamber and air flows ( For example, see Patent Document 1). In this case, the combustion gas is diluted by air flowing through the air passage downstream of the heat exchanger, whereby the humidity is reduced, and dew condensation in the exhaust pipe can be suppressed.

  By the way, in a general forced air supply type combustion device having no air passage, when the fins of the heat exchanger are clogged, the amount of air blown by the combustion fan decreases, and the work amount of the combustion fan decreases. (Fan current) decreases. Therefore, conventionally, there has been known an apparatus that determines the presence or absence of a fin blockage based on a fan current.

  However, in the forced air supply type combustion device having the above air passage, even if the fin is blocked, the amount of air flowing through the air passage increases, so that the amount of air blown by the combustion fan does not decrease to the left, and the fan current does not decrease. The occurrence of blockage cannot be detected.

JP 2004-138326 A

  In view of the above, an object of the present invention is to provide a forced air supply type combustion device having an air passage, which can detect occurrence of fin blockage in a heat exchanger.

  In order to solve the above-mentioned problems, the present invention provides a burner, a combustion chamber for burning an air-fuel mixture ejected from the burner, a combustion gas path through which combustion gas generated by combustion in the combustion chamber flows, and a combustion gas path. And a combustion fan for forcibly supplying air required for combustion, the downstream end of which is connected to a portion of a combustion gas path downstream of the heat exchanger. A bypass hole that communicates a part of the combustion chamber with the air passage, and a temperature sensor provided in a portion of the air passage downstream of the bypass hole. Means for judging the presence or absence of fin blockage of the heat exchanger based on the temperature detected by the temperature detecting means.

  According to the present invention, when the fins of the heat exchanger are clogged, the ventilation resistance in the heat exchanger increases, so that part of the combustion gas flows into the air passage through the bypass hole. For this reason, the temperature detected by the temperature detecting means provided in the portion of the air passage on the downstream side of the bypass hole increases, whereby it is possible to detect the occurrence of fin blockage.

1 is a cut-away side view of a forced-supply-type combustion device according to an embodiment of the present invention. FIG. 2 is a rear view of the forced air supply type combustion device of the embodiment. FIG. 5 is a flowchart showing a fin blockage discrimination process performed by the forced air supply type combustion device of the embodiment.

Figure 1 and with reference to FIG. 2, a forced air supply combustion apparatus according to an embodiment of the present invention includes a first housing 1 ₁ of the lower, second housing 1 ₂ on the first housing 1 ₁ When, a third housing 1 ₃ on the second housing 1 _2, a tubular member 2 extending from the third housing 1 ₃ upward, is provided at the upper end of the cylindrical body 2, it is driven by a motor 3a And a combustion fan 3.

The first housing 1 _1, and a plurality juxtaposed in the longitudinal direction (lateral direction in FIG. 1) longitudinal of the burner 4 is arranged in the lateral direction (direction orthogonal to a surface of FIG. 1). Then, the combustion chamber 5 to burn the mixture gas jetted from the burner 4 in the inner space of the above the first housing 1 ₁ of the burner 4 is configured, combustion gas path combustion gases flow generated in the combustion in the combustion chamber 5 6 is composed of the second internal space of the housing 1 _2, the internal space and the internal space of the cylindrical member 2 of the third housing 1 _3.

A lower surface of the first housing 1 ₁ is open. The combustion fan 3 by the suction force due to each burner 4 with the primary air is forcibly supplied, a large number of distribution holes formed in the distribution plate 7 which is arranged in the burner 4 below the first housing 1 ₁ The secondary air is forcibly supplied to the combustion chamber 5 via 7a. Further, the first lower front of the housing 1 ₁ are disposed gas manifold 8, the fuel gas is supplied from the nozzles provided in the gas manifold 8 to each burner 4. The burners 4 are light and light burners, and the gas manifold 8 is provided with a light nozzle 8a and a dark nozzle 8b corresponding to each burner 4.

The combustion gas path 6, by positioning the second housing 1 in _2, hot water supply and other heat exchanger 9 is disposed. The heat exchanger 9 is formed of a fin-and-tube heat exchanger composed of a plurality of heat absorbing fins 9a stacked in a lateral direction and a heat absorbing pipe 9b penetrating the heat absorbing fins 9a.

Further, the rear cover 10 opposite to exist a gap to the first and second rear plate ₁ 1 of the both bodies _{1 1} of a, _{1 2} a is provided, and back these rear plate ₁ 1 a, _{1 2} a An air passage 11 is formed between the air passage 11 and the cover 10 so that the air flows around the combustion chamber 5. The lower end of the air passage 11, i.e., the upstream end is open, upper end, i.e., the downstream end, the inner space of the third housing 1 ₃ is a part of the combustion gas path 6 on the downstream side of the heat exchanger 9 It is connected. According to this, air flows into the internal space of the third case 1 ₃ via the air passage 11 by the suction force generated by the combustion fan 3. Then, the combustion gas after passing through the heat exchanger 9 is diluted with air to lower the humidity, and it is possible to suppress dew condensation in an exhaust pipe (not shown) downstream of the combustion fan 3.

By the way, if the combustion device is used to some extent, clogging between the heat absorbing fins 9a of the heat exchanger 9, that is, fin blockage may occur. Therefore, as can be determined whether or not the fins closed, in the present embodiment, the upper portion than the burner 4 of the first housing 1 ₁ of the rear plate 1 _{1 a,} communicating a portion of the combustion chamber 5 to the air passage 11 In addition to forming the bypass hole 12, a temperature detecting means 13 composed of a thermistor is provided in a portion of the air passage 11 downstream of the bypass hole 12.

  When the fins of the heat exchanger 9 are clogged, the ventilation resistance in the heat exchanger 9 increases, so that part of the combustion gas in the combustion chamber 5 located upstream of the heat exchanger 9 It flows into the path 11 and the temperature detected by the temperature detecting means 13 rises. Therefore, in the present embodiment, the fin blockage determination processing shown in FIG. 3 is performed by the controller (not shown) when the burner 4 burns. In this determination processing, first, the detected temperature TH of the temperature detecting means 13 is read in STEP1, and then, the process proceeds to STEP2, and it is determined whether the detected temperature TH has become equal to or higher than a predetermined threshold YTH. If TH <YTH, the process returns to STEP 1. However, if TH ≧ YTH, it is determined that the fin has clogged, and the process proceeds to STEP 3 to perform an abnormality display and extinguish the burner 6.

  Although the embodiments of the present invention have been described with reference to the drawings, the present invention is not limited thereto. For example, in the above-described embodiment, the combustion fan 3 is provided on the downstream side of the combustion gas path 6 to supply air required for combustion by a suction method. However, the combustion fan is provided on the upstream side of the combustion chamber 5. Alternatively, the air required for combustion may be supplied in a forced manner. In this case, a part of the air from the combustion fan is pushed into the upstream end of the air passage 11.

In the above embodiment, both the first and second housings 1 _1, 1 ₂ is provided with the air passage 11 on the rear side, air the housings 1 _1, 1 ₂ of the front side and side surface side Roads can also be provided.

3 combustion fan, 4 burner, 5 combustion chamber, 6 combustion gas path, 11 air path, 12 bypass path, 13 temperature detection means.

Claims (1)

A burner, a combustion chamber for burning an air-fuel mixture ejected from the burner, a combustion gas path through which combustion gas generated by combustion in the combustion chamber flows, a heat exchanger disposed in the combustion gas path, and air required for combustion. And a combustion fan for forcibly supplying air, wherein the air flows around the combustion chamber, the downstream end of which is connected to a portion of the combustion gas path on the downstream side of the heat exchanger. In those having an air passage,
A bypass hole that communicates a part of the combustion chamber with the air passage; and a temperature detection unit provided in a portion of the air passage downstream of the bypass hole, and a fin of the heat exchanger based on a temperature detected by the temperature detection unit. A combustion device for determining the presence or absence of blockage.

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