JP4604186B2 - External combustion device - Google Patents

Description

  The present invention relates to an external combustion apparatus such as a heat source apparatus installed outdoors.

  Unlike the combustion apparatus installed indoors, the external combustion apparatus is safe without causing a CO poisoning accident. However, due to poor installation, such as when the combustion device is installed near the soot or an enclosure is provided around the combustion device, the combustion exhaust gas discharged from the exhaust port of the combustion device causes the combustion air to flow to the combustion part in the combustion device. A short circuit that recirculates into the air supply path may occur, resulting in incomplete combustion due to lack of oxygen.

  Therefore, conventionally, in an external combustion apparatus, a temperature sensor for detecting the temperature of the supply passage is provided, and the presence or absence of a short circuit is determined based on the temperature detected by the temperature sensor. A device that executes predetermined safety control such as combustion stop is known (see, for example, Patent Document 1).

When a short circuit occurs, the temperature of the air supply path rises due to mixing of high-temperature combustion exhaust gas. The above conventional example uses this phenomenon to determine the presence or absence of a short circuit. That is, if the temperature in the combustion device gradually rises during the operation of the combustion device and continues to operate for a certain amount of time, the temperature of the air supply path approaches that when a short circuit occurs, and the outside air temperature may be high. The temperature of the air supply path approaches that when a short circuit occurs, and the presence or absence of the short circuit cannot be accurately determined from the temperature of the air supply path.
JP 2000-240940 A

  In view of the above points, an object of the present invention is to provide an external combustion apparatus that can perform safety control by reliably determining a short circuit when it occurs.

  In order to solve the above problems, the present invention provides an external combustion apparatus installed outdoors, in which combustion exhaust gas discharged from an exhaust port of the combustion apparatus is supplied with combustion air to a combustion section in the combustion apparatus. Flowing through the air supply path in a short circuit determining means for determining the presence or absence of a short circuit that returns to the air path and safety control means for executing predetermined safety control when it is determined that there is a short circuit A CO sensor for detecting the CO concentration in the air is provided, and the short circuit determining means is configured to determine that there is a short circuit when the detected CO concentration of the CO sensor exceeds a predetermined value. .

  Here, when a short circuit occurs, incomplete combustion occurs and the CO concentration in the combustion exhaust gas increases, and this combustion exhaust gas enters the air supply path in the short circuit, so that CO in the air flowing through the air supply path Concentration increases. And according to this invention, in order to discriminate | determine the presence or absence of a short circuit based on the CO density | concentration detected by the CO sensor which detects the CO density | concentration in the air which flows into an air supply path, the influence in the temperature in a combustion apparatus or external temperature is influenced. Without receiving it, it is possible to accurately determine the presence or absence of a short circuit. Therefore, when a short circuit occurs, it is possible to reliably determine this and perform safety control by the safety control means.

  In the present invention, the safety control means performs control to reduce the combustion amount of the combustion section when it is determined by the short circuit determination means that there is a short circuit, and continues to be determined for a short time continuously after that. When this is done, it is desirable to perform control to stop combustion in the combustion section. Here, the short circuit may occur not only due to poor installation of the combustion apparatus, but also temporarily due to the influence of a gust of wind or the like. If the safety control means is configured as described above, when a temporary short circuit occurs due to a gust of wind or the like, only the control for reducing the combustion amount is performed and the combustion is not stopped. Since the combustion is improved by reducing the amount of combustion, the combustion apparatus can be continuously operated safely, and the user is not inconvenienced. On the other hand, when a permanent short circuit occurs due to poor installation of the combustion device, it is determined that there is a short circuit continuously for a predetermined time, combustion is stopped, and safety is ensured.

  Further, when the combustion device is a composite heat source machine having a first combustion section for hot water supply and a second combustion section other than hot water supply, for example, for heating or bathing, the safety control means includes the first combustion section and the first combustion section. If it is determined by the short circuit determination means that the short circuit is present at the time of simultaneous combustion with the two combustion sections, it is desirable to first perform control to reduce the amount of combustion in the second combustion section. According to this, when it is determined that there is a short circuit, the capability of hot water supply is maintained as it is, and only the capability of heating or bathing that does not immediately make the user feel inconvenient is limited. When a temporary short circuit occurs due to a gust of wind or the like, the combustion state is improved by restricting the ability of heating and bathing. Therefore, it is possible to cope with a short circuit without causing the user to feel inconvenience.

  In the embodiment to be described later, the steps corresponding to the short circuit discrimination means are steps S2 and S4 and steps S6 and S8 in FIG. 2, and the safety control means corresponds to steps S3 and S5. Steps S7 and S9.

  FIG. 1 shows a composite heat source machine having hot water supply and heating functions installed outdoors, which is an external combustion apparatus according to an embodiment of the present invention. This heat source device includes a combustion casing 1 disposed in an exterior case (not shown). A first combustion section 2 for hot water supply and a second combustion section 3 for heating are provided in the combustion casing 1. It has been.

  The 1st combustion part 2 is comprised by the 1st burner 4 and the 1st heat exchanger 5 for the hot water supply arrange | positioned above it, and the 2nd combustion part 3 is for the heating for the 2nd burner 6 arrange | positioned above it. And the second heat exchanger 7. Combustion air is supplied from the combustion fan 8 to the first burner 4 and the second burner 6 through the air supply passage 9. Further, the combustion exhaust gas from the first combustion unit 2 and the second combustion unit 3 flows into the exhaust passage 10 at the upper end of the combustion housing 1 and is discharged out of the machine through an exhaust port (not shown) opened in the exterior case. .

  The first heat exchanger 5 is connected to the upstream water supply pipe 5a and the downstream hot water discharge pipe 5b, and opens the hot water tap (not shown) at the downstream end of the hot water discharge pipe 5b to thereby form the first heat exchanger 5. When the water is passed through, the first burner 4 is ignited, and hot water having a set temperature set by a remote controller or the like is discharged from the tap. The second heat exchanger 7 is connected to a heating circuit (not shown) having a heating terminal such as floor heating via the forward pipe 7a and the return pipe 7b, and the second heat exchanger is connected to the heating circuit. Heating is performed by circulating hot water through 7.

  Gas is supplied to each of the first and second burners 4 and 6 via the electromagnetic on-off valves 41 and 61 and the electromagnetic proportional valves 42 and 62, respectively. Combustion is started and stopped, and the combustion amounts of the burners 4 and 6 are adjusted by the electromagnetic proportional valves 42 and 62. The electromagnetic on-off valves 41 and 61, the electromagnetic proportional valves 42 and 62, and the combustion fan 8 are controlled by the controller 11. During the operation of the first combustion unit 2 (during hot water supply operation) and during the operation of the second combustion unit 3 (during heating operation), the combustion amounts of the burners 4 and 6 corresponding to the hot water supply load and the heating load are calculated. The opening degree of the electromagnetic proportional valves 42 and 62 is controlled in accordance with the amount of combustion, and the rotational speed of the combustion fan 8 is controlled so that the amount of combustion air corresponding to the amount of combustion is supplied. In addition, a signal from a hot water temperature sensor 12 that detects the hot water temperature of the first heat exchanger 4 is input to the controller 11, and the first burner 4 based on the temperature detected by the hot water temperature sensor 12 during a hot water supply operation. Performs feedback control of the combustion amount.

  The controller 11 also receives a signal from a CO sensor 13 that detects the concentration of CO in the air flowing through the air supply path 9. Here, a short circuit occurs in which the combustion exhaust gas discharged from the exhaust port is recirculated to the air supply path 9 due to a poor installation such as the heat source device being installed near the firewood or an enclosure around the heat source device. Sometimes. When a short circuit occurs, incomplete combustion occurs and the CO concentration in the combustion exhaust gas increases, and this combustion exhaust gas is mixed into the air supply path 9 in the short circuit, so that the air in the air flowing through the air supply path 9 CO concentration increases. Therefore, in the present embodiment, the controller 11 determines the presence or absence of a short circuit based on the detected CO concentration of the CO sensor 13, and executes predetermined safety control when it is determined that there is a short circuit.

  Hereinafter, the presence / absence determination of the short circuit and the safety control will be described with reference to FIG. First, in step S1, it is determined whether or not it is a single combustion state in which only one of the first combustion unit 2 and the second combustion unit 3 is combusted. If it is the single combustion state, it is determined in step S2 whether or not the detected CO concentration of the CO sensor 13 is a predetermined value (for example, 100 ppm) or more. If the detected CO concentration is less than the predetermined value, it is determined that there is no short circuit, and one process is terminated. If the detected CO concentration is equal to or higher than the predetermined value, it is determined that there is a short circuit, and the amount of combustion in the combustion section during combustion is reduced in step S3. Next, in step S4, it is determined whether or not the state where the detected CO concentration is equal to or higher than a predetermined value has continued for a predetermined time (for example, 1 minute). If the determination result is “NO”, one process is performed as it is. Exit. On the other hand, if the determination result is “YES”, in step S5, the combustion of the combusting part during combustion is stopped, the subsequent operation of the heat source machine is prohibited, and the occurrence of abnormality is displayed.

  Here, a short circuit may occur temporarily due to the influence of a gust of wind or the like. When a temporary short circuit occurs, only the control to reduce the combustion amount is performed and the combustion is not stopped. Since the combustion is improved by reducing the combustion amount, it is possible to continue operating the heat source apparatus safely, and when it is determined that the detected CO concentration is less than the predetermined value in step S2 by releasing the short circuit, the combustion is performed. The amount is returned to the normal value and does not inconvenience the user. On the other hand, when a permanent short circuit occurs due to poor installation of the heat source machine, it is determined that there is a short circuit continuously for a predetermined time, combustion is stopped, and safety is ensured.

  In the simultaneous combustion state in which both the first and second combustion units 2 and 3 are combusted, the process proceeds from step S1 to step S6, and it is determined whether or not the detected CO concentration is a predetermined value or more. If the detected CO concentration is less than the predetermined value, one process is terminated as it is, but if the detected CO concentration is equal to or higher than the predetermined value, only the amount of combustion in the second combustion unit 3 is decreased in step S7. According to this, the capability of hot water supply is maintained as it is, and only the heating capability that does not immediately inconvenience the user is limited. When a temporary short circuit occurs due to a gust or the like, the combustion state is improved by limiting the heating capacity. Therefore, it is possible to cope with a short circuit without causing the user to feel inconvenience.

  Next, in step S8, it is determined whether or not the state in which the detected CO concentration is equal to or higher than the predetermined value has continued for a predetermined time. If the determination result is “NO”, one process is ended as it is. On the other hand, if the determination result is “YES”, the combustion of the second combustion unit 3 is stopped and the occurrence of abnormality is displayed in step S8.

  When the combustion of the second combustion unit 3 is stopped in this manner, the next combustion state is determined at step S1 and the processing at steps after S2 is performed. When it is determined in step S2 that the detected CO concentration is equal to or higher than the predetermined value, the combustion amount of the first combustion unit 2 is decreased in step S3, and the state where the detected CO concentration is higher than the predetermined value continues for a predetermined time thereafter. Then, the combustion of the 1st combustion part 2 is stopped by the step of S5.

  By the way, it is conceivable to provide a CO sensor in the exhaust passage 10 and determine the presence or absence of a short circuit based on the CO concentration in the combustion exhaust gas. However, since the CO sensor measures the CO concentration using the heat of oxidation reaction of CO by the oxidation catalyst, the measurable CO concentration becomes 500 ppm or more in a place where the atmospheric temperature is high such as the exhaust passage 10, Even if a short circuit occurs, it cannot be determined that there is a short circuit until the combustion state deteriorates considerably. On the other hand, in this embodiment, since the CO sensor 13 is disposed in the air supply path 9 having a low ambient temperature, a CO concentration of 100 ppm or less can be measured, and the presence or absence of a short circuit can be accurately determined based on the detected CO concentration.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to this. For example, in the above embodiment, the CO sensor 13 is provided in the air supply path 9 downstream of the combustion fan 8, but the suction port of the combustion fan 8 is also part of the air supply path, so that it faces this suction port. It is also possible to provide a CO sensor 13.

  In the above-described embodiment, the combustion amount is decreased in steps S3 and S7 by decreasing the opening degree of the electromagnetic proportional valves 42 and 62, but the present invention is not limited to this. For example, the burners 4 and 6 of each of the first and second combustion sections 2 and 3 are configured by arranging a plurality of unit burners in parallel, and the capacity is switched by increasing or decreasing the number of burning unit burners. When performing the above, the reduction of the combustion amount in the steps of S3 and S7 may be performed by reducing the number of unit burners to burn.

  Moreover, although the composite heat source machine of the said embodiment is provided with the 1st combustion part 2 for hot-water supply, and the 2nd combustion part 3 for heating, the 2nd combustion part 3 is for bath reheating or heating and a bath. It may be a commemorative one. Further, the present invention can be similarly applied to a heat source dedicated to hot water supply that does not include the second combustion unit 3 and an external combustion apparatus other than the heat source.

Explanatory drawing which shows the external combustion apparatus (composite heat source machine) of embodiment of this invention. The flowchart which shows the content of the short circuit discrimination | determination and safety control which the controller of the combustion apparatus of FIG. 1 performs.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... 1st combustion part, 3 ... 2nd combustion part, 9 ... Air supply path, 11 ... Controller (short circuit discrimination means, safety control means), 13 ... CO sensor.

Claims (3)

Whether there is a short circuit, which is an external combustion device installed outdoors, in which the combustion exhaust gas discharged from the exhaust port of the combustion device returns to the combustion air supply path to the combustion part in the combustion device In what comprises a short circuit determining means for determining, and a safety control means for executing a predetermined safety control when it is determined that there is a short circuit,
A CO sensor for detecting the CO concentration in the air flowing through the air supply path is provided, and the short circuit determining means is configured to determine that there is a short circuit when the detected CO concentration of the CO sensor exceeds a predetermined value. An external combustion apparatus characterized by that.   The safety control means performs control to reduce the amount of combustion in the combustion section when it is determined by the short circuit determination means that there is a short circuit, and when it is determined that there is a short circuit continuously for a predetermined time thereafter The external combustion apparatus according to claim 1, wherein the external combustion apparatus is configured to perform control for stopping combustion in the combustion section.   The combustion device is a combined heat source machine having a first combustion section for hot water supply and a second combustion section for uses other than hot water supply, and the safety control means is simultaneous combustion of the first combustion section and the second combustion section. 3. The outside arrangement according to claim 1, wherein when the short circuit determining means determines that a short circuit is present, control is first performed to reduce the amount of combustion in the second combustion section. Mold combustion equipment.

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