JP2005249251A - Gas combustion apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid the occurrence of abnormal combustion by detecting the trouble of an open/close valve before combustion and enable combustion operation by the remaining open/close valves excluding the troubled open/close valve. <P>SOLUTION: In this gas combustion apparatus, a fuel gas is regulated by a flow control type gas control valve before supplying and the downstream side thereof is branched by the plurality of open/close valves for switching a combustion capacity. If the detected flow amount value of a gas flow sensor varies when a main solenoid valve is opened with the first/second open/close valves 61a and 61b closed, one or both of the first/second open/close valves are abnormal in closing and, if it does not vary, the valves are determined to be normal, and output an open select signal to the first open/close valve. If the detected flow value varies, the first open/close valve is determined normal and, if it does not vary, it is determined to be abnormal in closing and outputs open switch signals to a second open/close valve by closing the first open/close valve. When the detected flow value varies, the valves are determined normal, and if it does not vary, the second open/close valve is determined to be abnormal in closing. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention supplies fuel gas after adjusting the flow rate to a predetermined flow rate through a flow control type gas control valve to a combustion section whose combustion capacity can be changed and switched by opening and closing of two or more on-off valves. In particular, the present invention relates to a technique capable of detecting the valve failure (valve abnormality) of the on-off valve before combustion and avoiding the occurrence of abnormal combustion in advance.

  Conventionally, as a technique for detecting a valve failure of a fuel gas supply system in a gas combustion apparatus, a source electromagnetic installed in the most upstream position of a fuel gas supply path provided in the gas water heater for a gas water heater. There has been proposed a valve that detects a valve failure of an original electromagnetic valve for switching supply / stop of fuel gas supply to a gas water heater from the outside (see, for example, Patent Document 1). In this device, a flow rate sensor is interposed in a fuel gas supply path located downstream of the original solenoid valve, and a valve failure of the original solenoid valve is detected based on a detected value of the fuel gas flow rate by the flow rate sensor. I am doing so. That is, even if an open control signal is output from the controller to the original solenoid valve in the closed state by executing combustion control of the combustion burner and ignition processing for the combustion burner is executed, if the ignition detection by the frame rod is not detected, the controller Now, the process proceeds to the determination of the failure location. If the flow sensor detects the flow rate of the fuel gas based on the output of the open control signal to the original solenoid valve, the failure location is determined to be other than the original solenoid valve. If the flow rate is not detected, the original solenoid valve is closed. It is determined that the valve has fallen into a valve failure state (so-called closed abnormal state) in which the valve is stuck without being opened due to the occurrence of a failure.

Japanese Patent Laid-Open No. 9-42666

  By the way, it is known as a combustion burner that the combustion part is divided into a plurality of parts and fuel gas supply switching is performed for each part through an on-off valve so that each part can be burned independently. Yes. In this case, the amount of combustion can be changed and switched by changing the number of parts to be burned by switching the opening / closing valve. In such a combustion burner, the fuel gas supply path at the downstream position of the original solenoid valve is branched by the plurality of on-off valves, and one or more on-off valves have fallen into the above-mentioned abnormal closed state. However, if any one of the plurality of on-off valves is normally opened in response to an open control signal from the controller, ignition is performed by ignition by an igniter. For this reason, even in the control that shifts to the failure determination on the condition that the ignition detection is not detected as in the above-described proposal, even the occurrence of the valve failure state cannot be detected.

  In addition, a gas control valve for making it possible to change and adjust the combustion amount by adjusting the supply amount of the fuel gas is usually interposed in the fuel gas supply path from the original solenoid valve to the combustion section. If this gas control valve is configured as a pressure control type, the fuel gas that has passed through the original solenoid valve is adjusted to the target pressure and supplied to each on-off valve on the downstream side. If configured, the fuel gas that has been combined with the flow rate sensor and passed through the original solenoid valve is adjusted to the target flow rate and supplied to each on-off valve on the downstream side. Therefore, when a part of the plurality of on-off valves is in a closed abnormal fault, if the pressure control type gas control valve is interposed, the pressure is adjusted according to the closed abnormal fault. Although the fuel gas adjusted to the target pressure will continue to be supplied to the downstream side, if the flow control type gas control valve is installed, the target flow rate when there is no abnormal closing failure will be The fuel gas having a greatly varied flow rate is supplied to the downstream side. For this reason, if a flow control type gas control valve is installed and if ignition occurs while some of the on-off valves are closed abnormally, the combustion state will include the amount of air and the amount of fuel gas. There will be an inconvenience that an abnormal combustion state greatly deviates from the normal air-fuel ratio.

  The present invention has been made in view of such circumstances, and an object of the present invention is to supply the fuel gas whose flow rate is adjusted by the flow control type gas control valve to the downstream side of the fuel gas supply path. In a gas combustion apparatus in which the downstream side of the fuel gas supply path is branched by a plurality of on-off valves for switching the combustion capacity, the occurrence of an abnormal combustion state can be avoided by detecting the on-off valve failure before combustion. In addition, when a failure occurs, the combustion operation can be performed by removing the on / off valve in the failed state.

  In order to achieve the above object, according to the present invention, a gas flow rate sensor for detecting the flow rate of fuel gas with respect to the fuel gas supply passage and a flow control type gas control valve are interposed, and the downstream of the fuel gas supply passage. A fuel gas whose flow rate is adjusted by the gas control valve is supplied to a combustion part connected to an end, and the combustion part is divided into two or more combustion parts, while the fuel gas supply path The downstream end side is branched through an on-off valve so that the fuel gas can be individually supplied to each combustion portion, and the combustion operation is performed by performing on-off switching control of the two or more on-off valves according to the required combustion amount. The following specific items are provided for the gas combustion apparatus provided with the control means. That is, it comprises a failure determination processing means for executing a failure determination as to whether or not a failure state has occurred in any of the two or more on-off valves before the start of combustion by the combustion operation control means, An open / close switching signal is individually output to the two or more open / close valves, and an open / close switching signal is output based on whether or not there is a change in the gas flow rate detected by the gas flow sensor before and after the output. The on / off valve is configured to determine whether or not a failure has occurred (claim 1).

  In the case of the present invention, if even one of the two or more on-off valves falls into a failure state, the occurrence of the failure state can be detected before the combustion starts in the combustion section. That is, if the on-off valve is normal, it will open from the closed state in response to the output of the open switching signal (open operation control signal), so that the flow of fuel gas should occur from the staying state until then. For this reason, it can be determined that a failure has occurred if there is no change in the detected gas flow rate in spite of outputting the open switching signal. If the occurrence of such a failure state is detected before combustion, the occurrence of abnormal combustion due to the failure can be avoided in advance. In particular, in the gas combustion apparatus of the present invention in which the fuel gas whose flow rate is adjusted by the flow rate control type gas control valve is supplied to the combustion section, the downstream on-off valve is maintained with the flow rate adjusted corresponding to the state where no failure occurs. If a failure such as a closing error occurs, the fuel gas supply flow rate will fluctuate significantly and the air-fuel ratio will be prone to an abnormal combustion state.On the other hand, if a failure state is detected before combustion, Even in the case of operation, it is possible to adjust the flow rate corresponding to the occurrence of the failure state, and a good combustion state can be realized. The on-off valve is for switching the combustion capacity, that is, for switching the combustion capacity, because whether the corresponding combustion portion is burned or not is switched by switching the opening / closing. For this reason, the on-off valve is sometimes referred to as a capacity switching valve for switching the combustion capacity.

  In the above-mentioned present invention, a more preferable action can be obtained by adding various additional specific items or adding further specific items. First, the combustion operation control means is configured to prohibit subsequent combustion operation when receiving an output of a determination result that at least one on-off valve is in a failure state from the failure determination processing means. It can be added (Claim 2). By doing so, it is possible to realize a uniform process of prohibiting the subsequent combustion operation by the gas combustion device due to the occurrence of a failure state, further improving the reliability and safety as the gas combustion device. You can get higher.

  Second, as the combustion operation control means, the output of the determination result that the specific on-off valve is in a failure state is received together with the specific information specifying which on-off valve from the failure determination processing means. In this case, it is possible to add a configuration in which a subsequent combustion operation is executed by the remaining on-off valve excluding the specific on-off valve and the combustion portion that receives the supply of fuel gas through the remaining on-off valve. ). When the combustion is uniformly prohibited due to the occurrence of a failure state as in the first case (Claim 2), the gas combustion apparatus is not used at all from the arrangement of the service person for repair to the repair by visiting. In the case of the above-mentioned second (in the case of claim 3), it becomes possible to perform combustion operation using the remaining on-off valve that operates normally and the corresponding combustion part. become. That is, it is possible to realize a combustion operation that satisfies the required combustion amount by performing on / off switching control using the remaining on-off valve in accordance with the required combustion amount, avoiding a situation where it becomes impossible to use at all, and improving user convenience It can contribute to the increase in sex.

  Third, as the failure determination processing means, the failure determination is performed in a state in which the opening degree of the flow control type gas control valve is changed to an opening degree corresponding to the minimum flow rate within the range in which the gas flow rate can be detected by the gas flow rate sensor. A configuration to be executed can be added (claim 4). In this way, the amount of fuel gas released from the combustion section in an unburned state when the on-off valve is normally opened by the output of the on-off valve open switching signal at the time of failure determination is made as much as possible. It can be reduced.

  Fourth, it is assumed that the gas combustion apparatus includes a blower fan that supplies combustion air to the combustion unit, and the failure determination processing unit operates the blower fan to purge the combustion unit while malfunctioning. A configuration for executing the determination can be added (claim 5). By doing in this way, it becomes possible to quickly purge and diffuse the fuel gas released from the above-mentioned combustion section while remaining unburned so as not to stay in the gas combustion apparatus. In particular, by combining with the specific matter of changing the fuel gas flow rate in the third case (in the case of claim 4) to the minimum flow rate, minimization of the fuel gas released unburned and the fuel gas flow rate The effect of rapid diffusion is obtained.

  As described above, according to the gas combustion device of any one of claims 1 to 5, even if one of the two or more on-off valves falls into a failure state, the occurrence of the failure state is detected by the combustion unit. Can be detected before the start of combustion, and the occurrence of abnormal combustion due to the failure can be avoided in advance. In particular, in the gas combustion apparatus of the present invention in which the fuel gas whose flow rate is adjusted by the flow control type gas control valve is supplied to the combustion section, it is possible to detect the occurrence of a failure state before combustion. Even when the fuel cell is operated, the flow rate of the fuel gas corresponding to the occurrence of the failure state can be adjusted, and a good combustion state can be realized.

  In particular, according to the second aspect of the present invention, it is possible to realize a uniform process of prohibiting the subsequent combustion operation by the gas combustion device due to the occurrence of a failure state, thereby further improving the reliability and safety of the gas combustion device. be able to.

  According to the third aspect of the present invention, it is possible to perform the combustion operation by using the remaining on-off valve that operates normally with the exception of the on-off valve in the failure state and the corresponding combustion portion, and with the occurrence of the failure state, It is possible to avoid the situation in which the gas combustion device becomes completely unusable and increase the convenience for the user.

  According to the fourth aspect, it is possible to reduce the amount of the fuel gas that is released from the combustion section in an unburned state as much as possible at the time of failure determination.

  Further, according to the fifth aspect, the fuel gas released from the combustion section without being burned in the failure determination can be quickly purged and diffused in the air so as not to stay in the gas combustion apparatus. be able to.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows, as an embodiment of the gas combustion apparatus of the present invention, a water heater for supplying hot water by heat exchange heating of incoming water with combustion heat. In this water heater, a combustion can body 2 is disposed in a casing 1, and a combustion burner 3 as a combustion section is disposed in a lower portion of the combustion can body 2, and receives combustion heat from the combustion burner 3. The water in the heat exchanger 4 is configured to be heat exchange heated. A blower fan 5 is attached to the lower side of the combustion can body 2, and the combustion air is blown and supplied to the combustion burner 3 by the operation of the blower fan 5.

  The combustion burner 3 is divided into a plurality of (two in the example of FIG. 1) combustion parts 31a and 31b each having a predetermined number of combustion pipes, and an individual on-off valve for each of the combustion parts 31a and 31b. The fuel gas from the fuel gas supply path 6 is individually supplied through 61a and 61b. That is, when the first on-off valve 61a is opened, fuel gas is supplied to the first combustion portion 31a, and the supplied fuel gas is combusted in the first combustion portion 31a together with the air from the blower fan 5, and similarly, the second When the on-off valve 61b is opened, fuel gas is supplied to the second combustion portion 31b and burned in the second combustion portion 31b.

  For example, a city gas supply pipe is connected to the upstream end of the fuel gas supply path 6 so that city gas is supplied as fuel gas at a predetermined supply pressure. The downstream end side of the fuel gas supply path 6 is The plurality of on-off valves 61a and 61b are branched by the number of combustion portions 31a and 31b. The fuel gas supply path 6 has an original solenoid valve 62 for switching supply / stop of fuel gas from the upstream side, a self-heating gas flow sensor 63 for detecting the flow rate of the fuel gas, and a downstream side. A flow control type gas control valve 64 for adjusting the flow rate of the fuel gas to be predetermined is interposed in this order.

  In addition, a water inlet path 7a is connected to one end side of the heat exchanger 4 and a hot water outlet path 7b is connected to the other end side. For example, a water pipe is connected to the upstream end of the water inlet 7a so that tap water is supplied at a predetermined supply pressure. Further, a hot water supply pipe or the like is connected to the downstream end of the hot water supply passage 7b, and the incoming water from the intake water passage 7a is heated by the heat exchanger 4 and discharged from the heat exchanger 4 to the hot water supply passage 7b. Hot water is supplied through a hot water supply pipe or the like to a currant or a bathtub (not shown). An inlet water flow sensor 71 for detecting the incoming water flow rate and an incoming water temperature sensor 72 for detecting the temperature of the incoming water are usually provided in the incoming water passage 7a, and a hot water temperature sensor for detecting the temperature of the outgoing hot water is provided in the outlet water passage 7b. (Not shown) and the like are interposed.

  The above-described combustion operation of the hot water heater is controlled by a controller 8 disposed in the casing 1. That is, the controller 8 includes a combustion operation control unit 81 as a combustion operation control unit, a failure determination processing unit 82 as a failure determination processing unit, and the like, and various input signals input to the remote controller 83 and various sensors 71 are input. , 72, 63, etc., combustion operation control, failure determination processing, and the like are performed.

  When the combustion operation control unit 81 receives a combustion request command, the normal combustion mode that is executed if all the on-off valves 61a and 61b are operating normally and at least one on-off valve 61a or 61b is in a failure state. And a failure combustion mode executed by receiving the output of the determination result. In the normal combustion mode, the operation control of the original solenoid valve 62, the flow control type gas control valve 64, the first and second on-off valves 61a and 61b, the blower fan 5, and the ignition means (not shown) is used as a combustion request command. Execute according to the accompanying required ability. For example, in the case of combustion operation control accompanying hot water supply operation for supplying hot water at a predetermined temperature, the temperature difference obtained by subtracting the detected incoming water temperature from the incoming water temperature sensor 72 from the set hot water temperature input by the user in the remote controller 83 is set. Then, by multiplying the detected incoming water flow rate from the incoming water flow rate sensor 71, the amount of heat necessary for heating up to the set hot water supply temperature is calculated, and the required capacity that is the amount of combustion heat that satisfies this amount of heat is calculated. If the required capacity is within a predetermined small number range (for example, Nos. 1 to 5), an open control signal is output only to the first on-off valve 61a to open the fuel, and fuel corresponding to the required capacity The opening degree of the gas control valve 64 is changed and adjusted so that the gas flow rate (target gas flow rate) is obtained. On the other hand, if the required capacity is in the large number range (for example, No. 5 to No. 10), the first and second on-off valves 61a and 61b are output by opening control signals and opened. Similarly, the opening degree of the gas control valve 64 is changed and adjusted so that the fuel gas flow rate (target gas flow rate) corresponds to the required capacity, and then the ignition means is ignited to start combustion.

  In the above combustion mode at the time of failure, when a combustion request command is received when receiving an output about the failure determination result of any one on-off valve 61a or 61b from the failure determination processing unit 82, combustion is performed according to the required capacity Start or prohibit combustion. That is, the required capacity can be satisfied only by combusting only one combustion portion 31b or 31a by opening only the other normal on-off valve 61b or 61a by excluding one of the on-off valves 61a or 61b in a failed state. In some cases, combustion is started, and combustion start is prohibited if the required capacity cannot be satisfied. In addition, if the output of the failure determination result is for both the first and second on-off valves 61a and 61b, the required capacity can no longer be satisfied, and combustion start is prohibited.

  The failure determination processing unit 82 executes failure determination processing every time a predetermined determination start timing is established. The establishment of the determination start timing is when hot water use (combustion use) is enabled in the present water heater. For example, the power switch of the remote control 83 is turned on to make the water heater usable. Executed when. In addition, when the hot water supply can be used, the failure determination process may be executed before the start of the combustion operation when a combustion request command is issued.

  The failure determination process is performed as follows. First, the blower fan 5 is actuated to make a pre-purge state before the combustion operation, and during this pre-purge process, a precondition process for making the original electromagnetic valve 62 and the gas control valve 64 into a predetermined open state is performed. , 61b are individually switched based on a failure diagnosis sequence (diagnostic step) set in advance, and whether or not the detected value of the fuel gas flow rate by the gas flow sensor 63 has changed before and after the switching. Determine if there is a failure. And when it determines with a failure state, while outputting the determination result to the combustion operation control part 81, it alert | reports to a user with the remote control 83 which is alerting | reporting means. This notification is performed by display or voice guidance.

  The opening / closing switching for failure diagnosis in the failure determination processing will be specifically described. As shown in FIG. 2, in the diagnosis step 1, the opening degree of the gas control valve 64 is set to a small opening corresponding to a predetermined minimum gas flow rate. When the first on-off valve 61a and the second on-off valve 61b are both closed, an opening operation signal (open switching signal) is output to the original electromagnetic valve 62. The minimum gas flow rate may be a flow rate value in the vicinity of the minimum flow rate value within the detectable flow rate range that can be detected by the gas flow rate sensor 63. In this way, the minimum gas flow rate is set within the range in which the gas flow rate can be detected by the gas flow rate sensor 63 for failure determination processing, and the fuel gas diffused into the air without being burned even though it is being pre-purged. This is to reduce the amount of the amount as much as possible. If both the first and second on-off valves 61a and 61b are normal, the first and second on-off valves 61a and 61b are maintained in the closed state. Therefore, even if the original electromagnetic valve 62 is opened, the flow rate detection value of the gas flow rate sensor 63 should not change. Therefore, if there is no change in the output value of the gas flow sensor 63 before and after the valve switching in the diagnosis step 1, it is determined that the first and second on-off valves 61a and 61b are both normal. It is determined that one or both of the first and second on-off valves 61a and 61b are in an open abnormal state where they are left open for some reason (for example, biting of foreign matter), and at least one on-off valve 61a or The failure determination result that / and 61b is in the failure state is output to the combustion operation control unit 81.

  If the determination result in the diagnosis step 1 is “normal”, the diagnosis step 2 outputs an opening operation signal only to the first on-off valve 61a from the state after the switching in the diagnosis step 1. If the first on-off valve 61a is normal, it receives an open operation signal and converts it to an open state so that the fuel gas flows. Therefore, the detected value of the gas flow sensor 63 also varies before and after the valve switching in the diagnostic step 2. Become. Accordingly, if there is a fluctuation in the output value of the gas flow sensor 63, it is determined that the first on-off valve 61a is operating normally. On the other hand, if there is no fluctuation in the output value, the first on-off valve 61a is fixed in the closed state. Therefore, it is determined that the closed abnormal state where the opening operation signal is not received even when the opening operation signal is received is made, and the next diagnosis step 3 is performed. Even in the diagnosis step 2, even if it is determined that the first on-off valve 61a is in a closed abnormal state, it is unknown whether it is only the first on-off valve 61a, and conversely the first on-off valve 61a is normal. This is because it is unclear whether the second on-off valve 61b is normal or not, and it is necessary to make a decision after performing the next diagnosis step 3 in addition to the diagnosis step 2.

  In the diagnosis step 3, a closing operation signal is output to the first on-off valve 61a from the state after the switching in the diagnosis step 2, and the state is once returned to the state of the diagnosis step 1. Thereafter, an opening operation signal is output only to the second on-off valve 61b. Since the first on-off valve 61a is normal, it should be converted into a closed state upon receipt of the above closing operation signal. If the second on-off valve 61b is also normal, it will be converted into an open state upon receipt of an opening operation signal. Therefore, the detected value of the gas flow sensor 63 fluctuates before and after switching from the diagnosis step 1 state. Accordingly, if there is a fluctuation in the output value of the gas flow sensor 63, it is determined that the second on-off valve 61b is operating normally. On the other hand, if there is no fluctuation in the output value, the second on-off valve 61b is fixed in the closed state. Therefore, it is determined that a closed abnormal state where the opening operation signal is not received even when the opening operation signal is received. Since the determination is confirmed in the above diagnosis steps 2 and 3, if it is determined that one or both of the first and second on-off valves 61a and 61b are in a failure state, the failure determination result is used as the combustion operation control unit. 81. As a result, the combustion operation control unit 81 enters the failure combustion mode and prohibits the combustion operation when both the first and second on-off valves 61a and 61b are in a failure state, that is, when all of them are in a failure state. Alternatively, if either one is in a failure state, combustion is started or burned depending on whether or not the required ability of the combustion request command can be satisfied by the remaining normal on-off valve 61a or 61b side combustion portion 31a or 31b. It will be judged whether to prohibit.

  If both the determination results in the diagnosis steps 2 and 3 are “normal”, the confirmation in the diagnosis step 4 is performed as a precaution. That is, a closing operation signal is output to the second on-off valve 61b from the post-switching state in the diagnostic step 3 to temporarily return to the state in the diagnostic step 1. Thereafter, an opening operation signal is output to both the first and second on-off valves 61a and 61, respectively. Since it is determined in diagnosis step 2 that the first on-off valve 61a is normal, and it is determined in diagnosis step 3 that the second on-off valve 61b is normal, both the first and second on-off valves 61a and 61b Since both receive the opening operation signal and convert to the open state and the fuel gas flows, the detected value of the gas flow rate sensor 63 fluctuates before and after switching from the state of diagnosis step 1. By confirming the fluctuation of the output value of the gas flow sensor 63, it is confirmed that all of the first and second on-off valves 61a and 61b are operating normally, and then the normal state. The determination result is output to the combustion operation control unit 81. As a result, the combustion operation control unit 81 starts combustion control in the normal combustion mode.

  According to the above embodiment, if a failure state such as a closing abnormality occurs in any of the plurality of on-off valves 61a and 61b for switching the combustion capacity, the occurrence of the failure state is reliably determined and detected. Can do. Then, the user who has been notified of the occurrence of the failure state by the remote controller 83 can promptly notify the service person of that fact and promote early termination of the repair. Moreover, since the occurrence of this failure state can be detected before the start of combustion, the occurrence of an inappropriate or abnormal combustion state can be avoided in advance. That is, for example, all the on-off valves 61a and 61b are both opened in order to perform the combustion operation in all the combustion portions 31a and 31b in the normal combustion mode even though one of the on-off valves 61a has failed due to an abnormal closing state. When the operation signal is output and the opening degree conversion signal corresponding to the target gas flow rate when the combustion control is performed in all the combustion portions 31a and 31b with respect to the flow rate control type gas control valve 64, the actual gas flow rate is as described above. This greatly deviates from the target gas flow rate, and a significant fluctuation in the air-fuel ratio leads to deterioration of the combustion state. On the other hand, in the present embodiment, it is possible to grasp the occurrence of the failure state before the start of combustion and to control the combustion only with the normal on-off valve 61b or 61a without the on-off valve 61a or 61b in which the failure state occurs. The opening degree conversion signal for the flow control type gas control valve 64 can also output a signal corresponding to the target gas flow rate in the case of the combustion operation assuming the normal on-off valve 61b or 61a. As a result, compared to the case where all of the water heater combustion operation is prohibited until a service person for repairing the failure of the on-off valve 61a or 61b in a faulty state is used, the hot water heater combustion operation is continued to use hot water. And the combustion operation can be realized by good combustion.

<Other embodiments>
In addition, this invention is not limited to the said embodiment, Various other embodiments are included. That is, in the above embodiment, the gas flow rate sensor 63 is disposed between the original solenoid valve 62 and the flow rate control type gas control valve 64. However, the present invention is not limited to this, and the gas flow rate sensor is not limited to the flow rate control type gas control valve. You may make it arrange | position in the downstream position.

  In the above embodiment, combustion is not prohibited as a process in the combustion mode at the time of failure, but the combustion operation is made possible under a predetermined condition. As long as at least one on-off valve 61a or 61b falls into a failure state, subsequent combustion may be uniformly prohibited.

  In the above embodiment, the combustion burner 3 is divided into two combustion portions 31a and 31b, and the downstream side of the combustion gas supply path 6 is branched into two by the two on-off valves 61a and 61b correspondingly. Not limited to this, the number of combustion portions may be made to be a number corresponding to that by branching into three or four or more by three or four or more on-off valves.

  In the above embodiment, a threshold value is set when determining whether or not the detection value of the gas flow sensor 63 has changed, and even if the detection value fluctuates within the threshold range, it is determined that the detection value is noise and there is no fluctuation, and exceeds the threshold value. If fluctuation occurs, it may be determined that there is fluctuation. This threshold value may be determined in relation to the sensitivity of the gas flow rate sensor 63 and the like.

  In the above embodiment, the water heater is shown as the gas combustion device, but the gas combustion device of the present invention may be applied to, for example, a gas fan heater.

  In the above-described embodiment, a plurality of on-off valves for switching the combustion capacity are targeted for failure determination. However, the original electromagnetic valve 62 may be added to the failure determination target. For example, if the original solenoid valve 62 is closed and the first and second on-off valves 61a and 61b are opened in the previous stage and the air blower fan 5 is operated and purged in this state, the original solenoid valve 62 is normally operated. If closed, the fuel gas supply path 6 on the downstream side tends to be low pressure. When the first and second on-off valves 61a and 61b are closed and the original solenoid valve 62 is opened on the first and second on-off valves 61a, the gas flow rate sensor 63 slightly changes the gas flow rate and detects it. The It can be determined whether or not a failure has occurred in the original solenoid valve 62 based on the presence or absence of this fluctuation.

It is a schematic diagram which shows a water heater as embodiment of the gas combustion apparatus of this invention. It is a graph which shows the switching of the valve for every diagnostic step in a failure determination process part, and the determination result based on the output value fluctuation | variation of a gas flow sensor.

Explanation of symbols

3 Combustion burner (combustion part)
6 Fuel gas supply path 8 Controller 31a, 31b Combustion part 61a, 61b On-off valve 63 Gas flow sensor 64 Flow control type gas control valve 81 Combustion operation control part (combustion operation control means)
82 Failure determination processing unit (failure determination processing means)

Claims (5)

A gas flow rate sensor for detecting the flow rate of the fuel gas to the fuel gas supply path and a flow control type gas control valve are interposed, and the gas control is performed on the combustion section connected to the downstream end of the fuel gas supply path. The fuel gas whose flow rate is adjusted by a valve is supplied, and the combustion part is divided into two or more combustion parts, while the downstream end side of the fuel gas supply path is connected to the combustion through an on-off valve. In the gas combustion apparatus provided with a combustion operation control means for branching the fuel gas for each part so that the fuel gas can be individually supplied, and performing the combustion operation by controlling the opening and closing of the two or more on-off valves according to the required combustion amount,
A failure determination processing means for executing a failure determination as to whether or not a failure state has occurred in any of the two or more on-off valves before the start of combustion by the combustion operation control means;
The failure determination processing means outputs an open / close switching signal individually to the two or more on / off valves, and based on whether or not there is a change in the detected gas flow rate by the gas flow sensor before and after the output for each output. A gas combustion apparatus configured to determine whether or not a failure state has occurred in the on-off valve that has output the on-off switching signal. The gas combustion apparatus according to claim 1,
The combustion operation control means is configured to prohibit subsequent combustion operation when receiving an output of a determination result that at least one on-off valve is in a failure state from the failure determination processing means. Gas combustion device. The gas combustion apparatus according to claim 1,
When the combustion operation control means receives the output of the determination result that the specific on-off valve is in a failure state together with the specific information specifying which on-off valve from the failure determination processing means, the specific operation A gas combustion apparatus configured to execute a subsequent combustion operation by a remaining on-off valve excluding the on-off valve and a combustion portion that receives supply of fuel gas through the remaining on-off valve. The gas combustion apparatus according to claim 1,
The failure determination processing means is configured to execute the failure determination in a state where the opening degree of the flow control type gas control valve is changed to an opening degree corresponding to a minimum flow rate within a flow rate detectable range by the gas flow rate sensor. A gas combustion device. The gas combustion apparatus according to claim 1 or 4, wherein
It has a blower fan that supplies combustion air to the combustion section,
The gas combustion apparatus, wherein the failure determination processing means is configured to execute a failure determination while operating the blower fan to purge the combustion section.

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