JP5593839B2 - Combustion device - Google Patents

Description

  The present invention relates to a combustion apparatus, and more particularly to a technique for preventing abnormal ignition in a combustion apparatus including a burner using gas as fuel.

  In a combustion apparatus provided with a burner using gas as fuel, unburned fuel gas (unburned gas) may be released from the burner due to failure of ignition to the burner or misfire after ignition. If the burner is ignited with such unburned fuel gas remaining in the vicinity of the burner above a certain concentration, abnormal combustion with explosion sound (so-called explosion ignition) is caused. Therefore, in this type of combustion apparatus, control for preventing explosion ignition is employed.

  For example, in the combustion apparatus shown in Patent Document 1, as a control for preventing such explosion ignition, when the flame detection sensor no longer detects flame due to a misfire or when a fire extinguishing operation is performed by the operator Is configured so that the ignition operation is not performed even if an ignition operation is performed by the operator until a certain time elapses until the unburned gas remaining in the burner is released to the outside of the burner.

  Further, in the combustion apparatus shown in Patent Document 2, when ignition has failed during the previous ignition operation, the ignition operation is performed with a delay from the normal operation after the ignition operation by the operation unit.

Japanese Patent Laid-Open No. 2-101319 JP 2002-130662 A

  These prior arts shown in Patent Document 1 and Patent Document 2 both prevent the occurrence of explosion ignition by prohibiting the ignition operation until a predetermined time elapses. There are various situations in which the gas is released, and the amount of unburned gas released varies depending on the situation. For this reason, if ignition is prohibited until a certain period of time has elapsed, there is a problem in that reignition is delayed and usability deteriorates even when there is little possibility of unburned gas emission and explosion ignition. .

  The present invention has been made in view of such problems, and the object of the present invention is a state in which ignition can be safely performed without explosion ignition depending on the situation where unburned fuel gas is released. It is an object of the present invention to provide a combustion apparatus that determines whether or not and permits an ignition operation.

In order to achieve the above object, a combustion apparatus according to claim 1 of the present invention includes a burner using gas as fuel, flame detection means for detecting a flame of the burner, and confirmation of ignition of the burner by the flame detection means. And a control means for performing misfire determination after confirming ignition, and a raw gas integration timer for integrating the discharge time of unburned fuel gas, and the control means receives the ignition operation by the operation means when the ignition operation is received. A combustion apparatus having a control configuration in which an ignition operation is not performed until an ignition prohibition time has elapsed when a time value of a gas integration timer is equal to or greater than a predetermined time, wherein the misfire determination of the control means is determined by the flame detection means It is started when the thermoelectromotive force in the state exceeds a predetermined threshold value from a state exceeding a predetermined value indicating the presence of a flame, and is configured to determine a misfire if the state below the threshold value continues for a certain period of time. In those, the control means, when it is determined that the misfire in the misfire determination, and, when receiving the fire extinguishing operation of the operation means during the determination process of the misfire determination, the predetermined in the raw gas accumulated timer A predetermined time value set in a range not reaching the time is added.

  That is, the combustion apparatus according to claim 1 determines whether or not fuel gas sufficient to cause explosion ignition remains in the vicinity of the burner as an integrated value of the unburned fuel gas release time (time value of raw gas integration timer). Judgment based on.

  Then, as control for preventing explosion ignition, the control means determines whether or not the time value of the raw gas integration timer is equal to or longer than a predetermined time when the ignition operation by the operation means is received, In the above case, the ignition operation is prohibited until the ignition prohibition time elapses, during which unburned gas is diffused and spontaneously discharged.

  Therefore, for example, even when unburned gas is released due to ignition failure, if the integrated value of the unburned gas release time is only a small amount that does not reach the predetermined time, the ignition operation is performed again. The ignition operation is allowed, and the combustion operation is promptly started. On the other hand, when the accumulated value of the unburned gas release time reaches the above-mentioned predetermined time due to repeated ignition failures (when the amount of unburned fuel gas released increases), prevention of explosion ignition The ignition operation is prohibited until the ignition prohibition time has elapsed.

In addition to such a control configuration, the combustion apparatus of the present invention is configured to extinguish the operating means when a misfire (so-called misfire) is detected after the ignition is confirmed , and during the misfire determination process. When an operation is accepted, a predetermined time value set in a range not reaching the predetermined time is added to the raw gas integration timer.

  In other words, this type of combustion apparatus is configured so that the supply of fuel gas to the burner is cut off when a misfire is detected in the middle, but from the occurrence of the misfire until the misfire is detected by the flame detection means. Since unburned gas is also released during this period, the count of the timer is advanced by adding a predetermined time value to the raw gas integration timer for the release of unburned gas during this period, and the raw gas integration timer is initialized. It counts up earlier than when counting from the value (when the timer is cleared).

  Here, as the predetermined time value to be added to the raw gas integration timer, the time value in a range not reaching the predetermined time is set to allow an ignition operation by a re-ignition operation performed after a misfire, and promptly This is so that the combustion operation can be restored. Therefore, this predetermined time-measured value is set shorter than the time obtained by subtracting the time during which unburned gas is released in at least one ignition operation from the predetermined time. Therefore, for example, when the time allowed for one ignition operation from the predetermined time is used as the time measurement value, if the ignition operation after a misfire is once failed, the subsequent ignition operation of the live gas integration timer is performed in the second ignition operation. The measured value reaches the predetermined time, and the ignition operation is prohibited in the second ignition operation.

Further, in the combustion apparatus according to the claim 1, when a user during the misfire determination process is performed extinguishing operation noticed misfire way also, since the raw gas integration timer predetermined timing value is added, extinguishing Explosive ignition due to unburned gas released before operation can be prevented.

A combustion apparatus according to claim 2 of the present invention includes a cancel timer for integrating the fuel gas supply cut-off time to the burner, and the control means has a time value of the cancel timer equal to or greater than the ignition inhibition time. In some cases, a control structure for returning the time value of the raw gas integration timer to the initial value is provided.

In the combustion apparatus according to claim 2 , the time value of the raw gas integration timer is reset to the initial value on condition that the time value of the cancellation timer for integrating the fuel gas supply cutoff time reaches the ignition inhibition time. This cancels the prohibition of the ignition operation.

Further, in the combustion apparatus according to claim 3 of the present invention, the predetermined time-measured value is set based on an estimated required time required from the occurrence of misfire after confirming ignition until the misfire is determined as misfire. It is characterized by.

In the combustion apparatus according to claim 3 , the predetermined time value added to the raw gas integration timer by the misfire determination is set based on the estimated required time until the misfire is determined from the occurrence of the misfire. Explosive ignition can be prevented by unburned gas released during the judgment process

Further, in the combustion apparatus according to claim 4 of the present invention, the burner has a main burner for heating the heat exchange means, and a seed fire burner for holding a seed fire for igniting the main burner. The flame detecting means is configured to detect the flame of the seed flame burner.

  According to the present invention, when the control means accepts the ignition operation by the operation means, it is determined whether or not the time value of the live gas integration timer is equal to or longer than a predetermined time. If the time value is equal to or longer than the predetermined time, ignition is prohibited. Since the ignition operation is prohibited until the time elapses, for example, when a small amount of unburned gas is released due to ignition failure, the ignition operation by the ignition operation is allowed again, and many times such as repeated ignition failure. When the unburned gas is released, the ignition operation is inhibited until the ignition inhibition time elapses, and the explosion ignition is prevented from occurring.

In addition, when a misfire occurs after the ignition is confirmed, or when a fire extinguishing operation is accepted during the misfire determination process , a predetermined time value is added to the raw gas integration timer, and the raw gas integration timer counts early. Therefore, it is possible to prevent the occurrence of explosion ignition due to the unburned gas released during the misfire determination process while enabling the ignition operation by the reignition operation.
In particular, even when the user notices a misfire during the misfire determination process and performs a fire extinguishing operation, a predetermined time value is added to the live gas accumulation timer, so that it is released before the fire extinguishing operation is performed. In addition, explosion ignition due to unburned gas can be prevented.

It is a schematic block diagram which shows an example which applied the combustion apparatus which concerns on this invention to the bathtub apparatus. It is an external appearance block diagram which shows an example of the operation knob of the operation part of the same bath apparatus. It is explanatory drawing which shows an example of misfire determination by the thermocouple (flame detection means) in the same bath apparatus. It is explanatory drawing which shows the outline | summary of the explosion ignition prevention processing procedure in the same bath apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an example of a combustion apparatus according to the present invention. Specifically, FIG. 1 shows a case where the combustion apparatus according to the present invention is applied to a bath apparatus.

  The bath device 1 is a balance-type bath device having a structure in which an air supply port and an exhaust port are exposed to the outside of the same atmosphere. FIG. 1 shows a hot water tap such as a caran K or a shower S. A bath tub device having a hot water supply function for supplying hot water is shown.

  The bath apparatus 1 includes a heat exchanger section 2, a combustion section 3, an operation section (operation means) 4, a display section 5, and a controller (control means) 6 as main parts.

  The heat exchanger unit 2 includes a bath heat exchanger 7 for bathing and a hot water supply heat exchanger 8 for hot water supply. The bath heat exchanger 7 is configured such that one end thereof communicates with the lower layer portion of the bathtub B and the other end communicates with the upper layer portion of the bathtub B. Is heated and introduced into the upper layer of the bathtub B, so that hot water in the bathtub B is circulated and heated. On the other hand, the hot water supply heat exchanger 8 has one end connected to a water supply source (not shown) such as a water supply and the other end connected to a hot water tap such as Karan K, and heats water supplied from the water supply source. Thus, it can be supplied to the hot water tap.

  The water supply source is connected to one end of a hot water supply heat exchanger 8 through a water inlet pipe 9, and the water inlet pipe 9 is provided with a water stop valve 10 capable of shutting off water supplied from the water source, and is not shown. Is equipped with a water governor for adjusting the incoming flow rate and a water flow switch for detecting water flow. A hot-water tap such as Karan K and shower S is connected to the other end (hot water side) of the hot water heat exchanger 8 via a tank 11 and a hot water switching unit 12. The hot water switching unit 12 includes a switching lever (not shown) that switches whether the hot water supplied from the hot water supply heat exchanger 8 is discharged from the hot water tap K or the shower S.

  Reference numeral 13 denotes an airing safety device (overheat prevention device). This air-fired safety device 13 is made of bimetal, and operates when the bath heat exchanger 7 is heated to a predetermined temperature (the operating temperature of the bimetal), and a safe operation such as closing of the original gas valve 17 by the controller 6. Is done. In addition, as this airing safety device 13, you may use a thermal fuse instead of a bimetal or with a bimetal.

  The combustion unit 3 is a combustion apparatus including a burner using gas as fuel, and a main burner (main burner) 15 for heating the heat exchanger unit 2 and a seed fire for igniting the main burner 15. The main part is a seed fire burner (pilot burner) 16 that holds Both the main burner 15 and the seed fire burner 16 are configured to receive the supply of fuel gas from a gas supply source (not shown) via the original gas valve 17.

  The original gas valve 17 is configured to be operated by a cam mechanism 32 that is interlocked with an operation of an operation unit 4 (specifically, an operation knob 30) described later. Unlike the gas valves 20, 21, etc., the cam mechanism 32 is used only when the valve is opened, and once the valve is opened, the valve open state is maintained by the holding current. That is, the original gas valve 17 is configured to close (close) when the holding current is interrupted.

  The fuel gas supplied from the gas supply source is connected to the main burner 15 on the downstream side (burner side) of the original gas valve 17 and the seed gas path 19 communicated to the seed burner 16. The main gas passage 18 is provided with a main gas valve 20 configured to cut off the supply of fuel gas to the main burner 15, and the seed gas passage 19 is connected to the seed fire burner 16. A pilot gas valve 21 configured to be able to shut off the supply of fuel gas is provided. Both the main gas valve 20 and the pilot gas valve 21 are configured so that the valves can be opened and closed by the action of a cam mechanism 32 interlocked with the operation of the operation unit 4.

  In addition to the main gas valve 20 and the pilot gas valve 21, the bath apparatus 1 shown in the present embodiment includes an auxiliary gas valve 22 for increasing the combustion capacity during hot water supply, a capacity switching gas valve 23, and the like. Is provided. The auxiliary gas valve 22 and the capacity switching gas valve 23 are gas valves provided to increase the amount of fuel gas supplied to the main burner 16, but the auxiliary gas valve 22 is an operation unit 4 described later. Is opened when a large hot water supply capacity ("hot water supply 2") is selected in the operation knob 30 (specifically, in the same manner as the main gas valve 20 and the pilot gas valve 21, it is linked to the operation of the operation unit 4). The capacity switching gas valve 23 is configured to be opened and closed by operating the capacity switching lever 24 regardless of the operation of the operation unit 4.

  An ignition plug 25 ignites the seed flame burner 16, and this ignition plug 25 is connected to an igniter 26. Reference numeral 27 denotes a frame rod that is a flame detection means of the main burner 15, and 28 is a thermocouple (thermocouple) that is a flame detection means of the seed flame burner 16, both of which are connected to the controller 6, 15 and the seed fire burner 16 are configured so that the presence or absence of flame (the presence or absence of combustion) can be confirmed.

  The operation unit 4 is an operation means of the bath apparatus 1, and includes a dial-type operation knob 30 as shown in FIG. The operation knob 30 is externally mounted on a main body case (not shown) of the bath tub device 1, and the user can perform operations related to operation settings of the bath tub device 1 by operating the operation knob 30. ing.

  Specifically, the operation knob 30 has an “fire extinguishing position” (see position P0 in FIG. 2) for stopping the combustion operation and an “ignition position” for igniting the seed fire burner 16 (see FIG. 2). 2), a “flaming position” (see position P2 in FIG. 2) for maintaining the state where the seed burner 16 is lit, and a “hot water supply” used for normal hot water supply (small hot water supply capacity). 1 ”(see position P3 in FIG. 2) and“ hot water supply 2 ”(see position P4 in FIG. 2) used for a large hot water supply capacity (large hot water supply capacity) are provided. When the position P2 is shifted to the position P3, the position P3 functions as a position for bathing.

  More specifically, the operation knob 30 is connected to a shaft 31 built in the main body case, and the operation knob 30 is set and operated to the operation positions (positions P0 to P4 in FIG. 2). Accordingly, the shaft 31 is configured to rotate. The shaft 31 is provided with a cam mechanism 32 as shown in FIG. It is configured to act on switches such as cam switches 41 and 42.

  Here, the cam mechanism 32 will be described. The cam 33 constituting the cam mechanism 32 is configured to perform the opening operation of the original gas valve 17 and the opening / closing operation of the main gas valve 20 and the pilot gas valve 21, and the cam 34 performs the opening / closing operation of the auxiliary gas valve 22. Configured to do. The cams 35 and 36 are configured to turn on / off cam switches 41 and 42 for inputting information related to the operation position of the operation knob 30 to the controller 6. That is, the controller 6 detects the operation position of the operation knob 30 based on the on / off state of these two cam switches 41 and 42. Further, the cam 37 is a cam mechanism for turning on / off the bath switch 43. When the bath switch 43 is in an off state, the water stop valve 10 is opened, and water supplied from a water supply source is supplied to the hot water supply. It is supplied to the heat exchanger 8.

  The display unit 5 is a display means for displaying the state of the bath apparatus 1. In the present embodiment, a display lamp (not shown) such as a light emitting diode is used as the display unit 5. The indicator lamp is externally mounted on the main body case of the bath apparatus 1 so that it can be visually recognized from the outside.

  The controller 6 is composed of a control board provided with a microcomputer (not shown) for controlling each part of the bath apparatus 1, and the controller 6 is based on the on / off states of the cam switches 41 and 42 described above. The operation position of the operation knob 30 is configured to be detected, and the operation of each part of the bath tub device is controlled in accordance with the detected operation position.

Here, the operation position of the operation knob 30 and the outline of the operation of the bath apparatus 1 will be described.
In the bathtub apparatus 1 of the present embodiment, when the operation knob 30 is in the fire extinguishing position (position P0), the main gas valve 17, the main gas valve 20, and the pilot gas valve 21 are all closed. Both the cam switches 41 and 42 are turned off.

  In the ignition operation of the bath apparatus 1, first, the operation knob 30 is shifted from the fire extinguishing position (position P0) to the ignition position (position P1). Thus, the original gas valve 17 and the pilot gas valve 21 are opened by the action of the cam 33 interlocked with this operation (at this time, the main gas valve 20 is closed by the cam 33). Along with this, the cam switch 41 is turned on and the cam switch 42 is turned off, and the controller 6 detects that the operation knob 30 has shifted to the ignition position from the state of the cam switches 41 and 42, and the seed fire burner 16. Is ignited. That is, the igniter 26 is turned on and the spark plug 25 is in an ignition state. As a result, if the ignition fails, the seed fire is lit on the seed fire burner 16.

  When the ignition operation to the seed fire burner 16 is performed, the controller 6 next checks whether the seed fire burner 16 is ignited. This confirmation is made based on whether or not the thermoelectromotive force in the thermocouple 28 exceeds a predetermined value indicating the presence of flame. When the ignition to the seed flame burner 16 is confirmed, the controller 6 holds the original gas valve 17. Current is supplied to keep the original gas valve 17 open. At this time, the main gas valve 20 remains closed, and the operation knob 30 automatically shifts to the ignition position (position P2) upon ignition confirmation.

  The controller 6 that has confirmed the ignition described above monitors the thermoelectromotive force of the thermocouple 28 until the operation knob 30 is returned to the fire extinguishing position, and whether or not the misfire is caused in the middle of the seed burner 16. Make a misfire determination. FIG. 3 shows an example of this misfire determination. As shown in FIG. 3, when the pilot flame burner 16 is ignited, the thermoelectromotive force of the thermocouple 28 rises and maintains a substantially constant state while the ignition state is maintained. The thermoelectromotive force of the thermocouple 28 decreases with time. The controller 6 starts the misfire determination when the thermoelectromotive force of the thermocouple 28 falls below the threshold value X for starting the misfire determination after the ignition confirmation. This misfire determination is performed based on whether or not the state where the threshold value X is lower than the threshold value X is continued for a certain time t2 or longer, and the state where the thermoelectromotive force is lower than the threshold value X after the predetermined time t2 is continued. Then, it is determined as misfire (middle misfire). When such a misfire is detected, the controller 6 cuts off the holding current supplied to the original gas valve 17, closes the original gas valve 17, and releases unburned fuel gas. To prevent.

  When hot water is to be supplied, the operation knob 30 is shifted from this state (the state of the ignition position) to a hot water supply position (for example, position P3 of “hot water supply 1”). As a result, the main gas valve 20 is opened by the action of the cam 33 that is interlocked with the operation of the operation knob 30, the fuel gas is supplied to the main burner 15, and the seed fire that is lit on the seed burner 16 is supplied to the main burner 15. The main burner 15 is combusted by the fire transfer, and the hot water supply operation is started. Note that the combustion confirmation of the main burner 15 and the misfire determination are performed by the frame rod 27.

  Thus, when the operation knob 30 is in the hot water supply position, the bath switch 43 is turned off and the water stop valve 10 is opened. That is, the water supplied from the water supply source is supplied to the water inlet side of the hot water supply heat exchanger 8. When the operation knob 30 is set to “hot water supply 1” (position P3), the cam switches 41 and 42 are both turned on, and the controller 6 determines that the operation knob is “hot water supply” from the state of the cam switches 41 and 42. 1 ”is detected, and it is determined whether the flame of the main burner 15 is detected by the frame rod 27.

  When the operation knob 30 is operated from the ignition position to the hot water supply position (position P4) of “hot water supply 2”, the auxiliary gas valve 22 together with the main gas valve 20 is operated by the action of the cam 33 and the cam 34 linked to this operation. And a larger amount of fuel gas is supplied to the main burner 15 than in the case of the “hot water supply 1”, and a hot water supply operation with a large hot water supply capacity is performed. At this time, the cam switch 41 is turned off, the cam switch 42 is turned on, and the bath switch 43 is turned off.

  On the other hand, when retreating the bath, the operation knob 30 is pushed down to shift to the position P3. As a result, the main gas valve 20 is opened by the cam 33 (fire transfer to the main burner 15 is started), the bath switch 43 is turned on by the cam 37, the water stop valve 10 is closed, and the bath follower is turned on. A whispering operation is started.

  On the other hand, when stopping the hot water supply operation or the bath reheating operation, the operation knob 30 is moved to the fire extinguishing position. As a result, the main gas valve 20 and the pilot gas valve 21 are closed by the action of the cam 33, and the holding current supplied to the original gas valve 17 by the control unit 6 is cut off, and the original gas valve 17 is closed. Therefore, when the operation knob 30 is set to this fire extinguishing position, the seed fire burner 16 and the main burner 15 are extinguished. When the operation knob 30 is in the fire extinguishing position, both the cam switches 41 and 42 are turned off and the bath switch 43 is turned on.

  Next, control for preventing explosion ignition in the bath apparatus 1 configured as described above will be described with reference to FIG. FIG. 4 is an explanatory diagram showing an outline of the procedure of the explosion ignition prevention process.

  The bath apparatus 1 shown in the present embodiment does not include scavenging means (ventilation fan) for forcibly exhausting unburned fuel gas to the outside in the combustion unit 3. Control for preventing explosion ignition due to residual is provided, and in performing this control, the microcomputer of the controller 6 includes a raw gas integration timer for integrating the discharge time of unburned fuel gas, and a fuel to the combustion unit 3. A cancel timer is set on the program to set the timing for integrating the gas supply cutoff time and returning the count value (time value) of the raw gas integration timer to the initial value.

  When the controller 6 receives an ignition operation by the operation knob 30 (specifically, an operation for setting the operation knob 30 to the ignition position) (see step S1 in FIG. 4A), the controller 6 starts counting the raw gas integration timer. At the same time (see step S2 in FIG. 4A), it is determined whether or not the count value of the raw gas integration timer is equal to or longer than a predetermined time Ta (50 seconds in the illustrated example) (steps S3a and S3b in FIG. 4A). reference).

  Since the raw gas integration timer is a timer for integrating the discharge time of unburned fuel gas, the count value of this timer is substantially proportional to the discharge amount of unburned fuel gas. That is, when the integration time indicated by this count value is long, it means that there is a large amount of unburned fuel gas remaining in the vicinity of the combustion section 3. Therefore, the controller 6 that has received the ignition operation executes the explosion ignition prevention process based on the count value of the raw gas integration timer if the count value is equal to or greater than the predetermined time Ta, and the predetermined ignition prohibition time Tb has elapsed. Until this is done, the ignition operation is not performed without turning on the igniter 26 (see step S4 in FIG. 4A). When this processing is performed, the original gas valve 17 is also closed together with the igniter 26 not being turned on, so the controller 6 is configured to clear the cancel timer and return the count value to the initial value. (Refer FIG.4 (a) step S5).

  Here, the predetermined time Ta is set based on the time required to release the amount of fuel gas expected to cause explosion ignition during the ignition operation. That is, since the original gas valve 17 and the pilot gas valve 21 are opened during the ignition operation, the time required for releasing the amount of fuel gas that is expected to cause the explosion ignition of the seed flame burner 16 with these valves open. It is set in a range that does not reach. However, the amount of fuel gas that causes the ignition of the seed burner 16 varies depending on the structure of the combustor 3 and the gas type of the fuel gas, so that the predetermined time Ta is the model of the bath apparatus 1 and the fuel used. It is set according to the gas.

  On the other hand, when the count value of the raw gas integration timer when the ignition operation is received is less than the predetermined time Ta, there is no risk of explosion ignition, so the explosion ignition prevention process is not performed, and the controller 6 In accordance with the ignition operation, the igniter 26 is turned on to perform an ignition operation (see step S6 in FIG. 4A). In this case, the controller 6 confirms whether or not the seed flame burner 16 is ignited based on the thermoelectromotive force of the thermocouple 28 (see step S7 in FIG. 4 (a)), and is normally ignited. Then, the raw gas integration timer is cleared and the count value is returned to the initial value (see step S8 in FIG. 4 (a)). That is, when the ignition is normally performed, the unburned fuel gas around the seed burner 16 is consumed by the combustion of the burner, so that the count value of the raw gas integration timer is returned to the initial value before counting.

  Then, after the start of the combustion of the seed burner 16, the misfire determination by the thermocouple 28 described above is performed, and when misfire is detected halfway (when misfire is determined in the misfire determination (see step S <b> 9 in FIG. 4A)). Adds a predetermined count value Tc (a count value for 45 seconds in the illustrated example) preset in the raw gas integration timer (see step S10 in FIG. 4A).

  Here, when a misfire is detected during the process, the count value Tc is added to the raw gas integration timer because the unburned gas is released until the original gas valve 17 is closed due to the detection of the intermediate misfire (or to it). This is to add the (close time) to the live gas integration timer. That is, until the controller 6 determines that there is a misfire after a misfire has occurred, as shown in FIG. 3, the thermoelectromotive force of the thermocouple 28 decreases from the misfire occurrence to the threshold X for misfire determination start. Since the time t1 required for the elapse of time and the time t2 required for the misfire determination elapse, the unburned gas released during this time is counted by the raw gas integration timer. In other words, the count value Tc is set based on a required time estimated to be required from the occurrence of misfire after the ignition is confirmed until the misfire is determined by the misfire determination. Since the estimated required time varies depending on the type of the thermocouple 28 and the like, the count value Tc is also set according to the model of the bath apparatus 1.

  In this embodiment, the count value (time to be added to the raw gas integration timer) Tc is set within a range not reaching the predetermined time Ta (that is, Ta> Tc). This is because the count value Tc is added to the live gas integration timer due to a misfire during the course, so that the ignition operation is not prohibited because the count value of the live gas accumulation timer reaches the predetermined time Ta during the reignition operation performed after the mid-fire misfire. It is for doing so. That is, at least one reignition operation is to be accepted by the controller 6. Therefore, the count value Tc is set to be shorter than the predetermined time Ta minus the time during which unburned gas is released in at least one ignition operation.

Thereby, in the bathtub apparatus 1 of this embodiment, even if the flame of the seed fire burner 16 disappears due to the misfire during the course, the ignition operation to the seed fire burner 16 is performed by the ignition operation that is performed thereafter, so Can return to.

  FIG. 4B shows the operation of the cancel timer. As described above, the cancel timer is a timer for integrating the fuel gas supply cut-off time to the burner, and therefore, when the original gas valve 17 is closed, that is, when the operation knob 30 is set to the fire extinguishing position. Counting is started when the holding current to the original gas valve 17 is interrupted (see steps S1 and S2 in FIG. 4B).

  Since this cancel timer functions as a timer for setting the timing for returning the count value of the raw gas integration timer to the initial value, the ignition prohibition time Tb (300 seconds in the illustrated example) elapses from the start of the count. Accordingly, the count value of the raw gas integration timer is cleared (see steps S3 and S4 in FIG. 4B).

  Here, the ignition prohibition time Tb is a time required for the unburned fuel gas remaining in the combustion section 3 to be diffused and discharged naturally without using scavenging means, and to be diluted to a concentration at which no explosion ignition occurs, In the present embodiment, 300 seconds is set as the ignition inhibition time Tb. Therefore, in the bathtub apparatus 1 shown in the present embodiment, when the state continues for 300 seconds after the original gas valve 17 is closed, the count value of the raw gas integration timer is cleared, and an ignition operation by an ignition operation can be performed. .

  Thus, in the bathtub apparatus 1 shown in the present embodiment, when the controller 6 accepts the ignition operation, it is determined whether the count value of the raw gas integration timer is equal to or greater than the predetermined time Ta, and is equal to or greater than the predetermined time Ta. If so, the ignition operation is prohibited until the ignition prohibition time Tb elapses. Therefore, for example, when only a small amount of unburned gas is released due to ignition failure, ignition by reignition operation is allowed. When a large amount of unburned gas is released due to repeated ignition failures, the ignition operation is prohibited until the ignition inhibition time Tb elapses, and explosion ignition is prevented from occurring.

  In addition, when a misfire occurs after the ignition is confirmed, a predetermined count value Tc is added to the live gas integration timer so that the live gas integration timer counts up early. While enabling the ignition operation by operation, it is possible to prevent the occurrence of explosion ignition due to the unburned gas released during the misfire determination process.

  The above-described embodiments show preferred embodiments of the present invention, and the present invention is not limited to these, and various design changes can be made within the scope of the invention.

  For example, in the embodiment described above, the case where the present invention is applied to a balance-type bath tub device is shown. However, the present invention is not limited to such a bath tub device. It is also applicable to water heaters and gas stoves.

  Further, in the above-described embodiment, the case where the predetermined count value Tc is added to the raw gas integration timer at the time of misfire detection by the misfire determination is shown, but for example, when the operation knob 30 is returned to the fire extinguishing position during the misfire determination. In addition, a predetermined count value Tc may be added to the raw gas integration timer in the same manner as when a misfire is detected. Thus, even when the user returns the operation knob 30 to the fire extinguishing position before the misfire determination is completed, the amount of unburned fuel gas released is added to the raw gas integration timer, and the explosion ignition by the subsequent reignition operation is performed. Can be prevented.

  Moreover, although the case where the thermocouple 28 was used as a flame detection means of the seed flame burner 16 was shown in embodiment mentioned above, if it is a sensor which can detect the presence or absence of a flame, other sensors, for example, a frame rod, are used. Is also possible.

1 Bath pot device (combustion device)
2 Heat exchanger section 3 Combustion section 4 Operation section (operation means)
5 Display unit 6 Controller (control means)
7 Bath heat exchanger 8 Hot water supply heat exchanger 9 Inlet pipe 10 Water stop valve 12 Hot water switching unit 15 Main burner 16 Type fire burner 17 Original gas valve 20 Main gas valve 21 Pilot gas valve 22 Auxiliary gas valve 23 Capacity switching gas valve 30 Operation knob 32 Cam mechanism 41, 42 Cam switch 43 Bath switch

Claims (4)

A burner using gas as fuel, a flame detection means for detecting a flame of the burner, a control means for performing an ignition check on the burner by the flame detection means and a misfire determination after the ignition check, an unburned fuel gas With a raw gas integration timer that integrates the release time,
The control means has a control configuration in which an ignition operation is not performed until an ignition prohibition time elapses when an ignition operation by the operation means is received and the time value of the raw gas integration timer is not less than a predetermined time. A combustion device,
The misfire determination of the control means is started when the thermoelectromotive force in the flame detection means falls below a predetermined threshold value from a state where the thermoelectromotive force exceeds the predetermined value indicating the presence of flame, and is in a state below the threshold value Is configured to determine misfire if it continues for a certain period of time,
When the control means determines that the misfire has occurred in the misfire determination, and when a fire extinguishing operation of the operation means is received during the misfire determination determination process, a range that does not reach the predetermined time in the raw gas integration timer A combustion apparatus characterized by adding a predetermined time value set in (1). A cancel timer for integrating the fuel gas supply cut-off time to the burner,
2. The control unit according to claim 1 , further comprising a control configuration for returning the time value of the raw gas integration timer to an initial value when the time value of the cancel timer is equal to or greater than the ignition inhibition time. Combustion equipment. 3. The combustion apparatus according to claim 1, wherein the predetermined time-measured value is set based on an estimated required time required until a misfire is determined by a misfire determination after the occurrence of a misfire after ignition is confirmed. . The burner comprises a main burner for heating the heat exchange means, and a seed fire burner for holding a seed fire for igniting the main burner,
The combustion apparatus according to any one of claims 1 to 3 , wherein the flame detection means is configured to detect a flame of the seed fire burner.

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