JPH0711335B2 - Combustor failure detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a device for detecting a combustor failure.

<Prior art> First, in a conventional combustor configured to instantaneously supply hot water having a temperature set by on-off cycle combustion,
For example, how the relay circuit for driving the fuel supply pump (hereinafter, abbreviated as load) was controlled will be described based on the control circuit shown in FIG.

The conventional control circuit includes a DC power supply circuit 210, a load driving relay 251, a relay series resistor 252, and a relay series diode 25.
And a constant voltage power is supplied to the relay circuit 257 (diode 242 and diode series resistor 2
The constant voltage output circuit 244 (composed of 41) and the constant voltage power output from the constant voltage output circuit 244 (via the microcomputer output transistor 232) by inputting the operation switch signal and the flame detector signal to the relay circuit 257. The microcomputer 231 to be applied and the DC voltage output from the DC power supply circuit 210 are input to supply the power to the first microcomputer 231 via the electric line 227, and secondly to the constant voltage output circuit 244 (Zener diode). Voltage monitoring circuit 220 which supplies constant voltage power (via circuit 266).

The conventional voltage monitoring circuit 220 described above supplies constant voltage power to one load by the method shown in FIG.
If there are two or more burners even if there are a plurality of burners or if there is only one burner, for example, if there are two loads, the conventional method is followed,
As shown in FIG. 2, a first relay circuit 257 including a first relay 251 that drives one load, for example, a fuel supply pump, and a second relay that drives another load, for example, a fuel supply opening / closing valve.
The constant voltage power supply must be controlled for the two relay circuits of the second relay circuit 258 including 254. Therefore, as shown in FIG. 2, the constant voltage output circuit for supplying the constant voltage power also has the above-mentioned parallel first relay circuit 257 and second parallel circuit 257.
In addition to the conventional first constant voltage output circuit 244 including the first diode 242, a second constant voltage output circuit 245 including a second diode 243 connected in parallel with the diode is provided corresponding to each of the relay circuits 258. It is necessary (however, the diode series resistor 241 can be commonly used for the first constant voltage output circuit 244 and the second constant voltage output circuit 245). Further, the microcomputer 231 also includes the first constant voltage output circuit 244 and the second constant voltage output circuit 245 as the first relay circuit 257.
2 and the second relay circuit 258 must be controlled so that the microcomputer output transistor also has two transistors, a first microcomputer output transistor 232 and a second microcomputer output transistor 233, as shown in FIG. become.

<Problems to be Solved by the Invention> As shown in FIG. 2, a first constant voltage output circuit 244 and a second constant voltage output circuit 244 are provided.
When the first diode 242 and the second diode 243 are connected in parallel in the constant voltage output circuit 245, if any one of the diodes is short-circuited or the anode and the cathode are reversely connected due to the wiring connection, The following inconveniences occur. That is, for example, to turn on only the first relay circuit 257 that drives one load (fuel supply pump) (that is, to add the power of the first constant voltage output circuit 244 to the first relay circuit 257), the microcomputer 231 If only the first microcomputer output transistor 232 is turned on, if the second
Assuming that the diode 243 is short-circuited or reversely inserted, the application point of this ON signal by the microcomputer 231 via the first microcomputer output transistor 232 is the circuit point 246.
Even though it should only be
It goes from the circuit point 246 to the circuit point 247 via and is also applied to the circuit point 247. As a result, the first relay circuit for driving the fuel supply pump is driven by this microcomputer signal.
Not only 257 is turned on, but also the second relay circuit 258 for driving the fuel supply opening / closing valve is turned on.

The present invention detects the presence / absence of a failure in which diode of the constant voltage output circuit is short-circuited or reversely connected by reversely utilizing the nature of the above problems, and further, based on the detection result, the control target The purpose is to monitor whether the load on and off is accurately performed.

<Means for Solving the Problems> In order to achieve the above object, a failure detecting device for a combustor according to the present invention is provided with a burner including a fuel supply opening / closing valve and a flame detector, and a burner for the burner. Combustion having at least a common fuel supply pump for sending oil through the fuel supply on-off valve, and instantaneously supplying hot water having a temperature set by on-off cycle combustion that repeats on-off in a relatively short cycle A failure detection device for a vessel,
A direct current power supply circuit, a second relay circuit for driving at least the fuel supply on-off valve, and a first circuit connected in parallel with the circuit.
A relay circuit, a first constant voltage output circuit and a second constant voltage output circuit connected in parallel corresponding to each of the first and second relay circuits, and the first constant by inputting an operation switch signal. The constant voltage power output from the voltage output circuit and the second constant voltage output circuit is applied to the first relay circuit and the second relay circuit, and the flame non-detection signal from the flame detector is input to the second relay circuit. A microcomputer for stopping the application of the constant voltage power to the relay circuit, and the DC voltage output from the DC power supply circuit are input to supply power to the microcomputer and the first constant voltage output circuit and the second constant voltage output. A first diode and a second die which have a voltage monitoring circuit for supplying constant voltage power to the circuit, and are connected to the first constant voltage output circuit and the second constant voltage output circuit at the anode side thereof. And the microcomputer first outputs a second relay circuit applied voltage application stop signal for closing the fuel supply opening / closing valve when the combustion time of the first cycle accompanying the start of the on / off cycle combustion has elapsed, If the flame non-detection signal from the flame detector is not input even after a certain period of time, it is determined that the second diode of the constant voltage output circuit is short-circuited or reversely inserted. It has a feature.

<Operation> According to the above-mentioned feature of the present invention, the microcomputer in the combustor failure detection device of the present invention first sends the closing signal of the fuel supply on-off valve when the combustion time of the first cycle accompanying the start of the on-off cycle combustion has elapsed. If the flame non-detection signal from the flame detector does not reach the microcomputer even after a certain time has elapsed after the output, the microcomputer outputs constant voltage power to the second relay circuit for driving the fuel supply on-off valve. It can be clearly determined that the second diode in the second constant voltage output circuit is faulty (ie shorted or reverse-inserted). That is, if the combustor failure detection device of the present invention is used, as described above, whether the diode of the constant voltage output circuit is normal is monitored by monitoring the state of the load by the input from the flame detector to the microcomputer. Whether or not the constant voltage output circuit is normal can be detected, and whether or not the load to be controlled is turned on and off can be monitored by the detection result.

<Example> A combustor failure detection device of the present invention will be described based on an example thereof.

FIG. 1 is an overall configuration diagram of an oil water heater showing a case where the failure detection device for a combustor of the present invention is used for detecting a failure of an oil water heater, and FIG. 2 is a circuit diagram of a control unit of this embodiment, FIG. 3 is a time chart showing the operation of this embodiment.

First, FIG. 1 will be outlined. The oil water heater shown in this figure
Combustion can body 10, combustion chamber 11, gun type small burner 20, first jet nozzle 21, first igniter 22, first flame detector 23, first
Fuel supply on-off valve 24, gun type large burner 30, second ejection nozzle 31, second igniter 32, second flame detector 33, second fuel supply on-off valve 34, fuel supply pump 40, blower fan 50, heat for hot water supply Exchanger 60, water inlet pipe 61, hot water outlet pipe 62, water amount sensor 63, control unit 70, remote controller (hereinafter abbreviated as remote controller)
80, hot water supply operation switch 81, failure display lamp 82.
The combustor failure detection device of the present invention is included in the controller 70 described above.

The configurations and functions of the other circuit portions of the circuit in the control unit 70 shown in FIG. 2 except the microcomputer 231 are as described in detail in <Prior art> and <Problems to be solved by the invention>. Therefore, we will put Fig. 2 aside for the time being and explain the function of the microcomputer and the operation of each combustor device (hereinafter abbreviated as "load") based on the time chart of Fig. 3, and then with reference to Fig. 2 together. The main points of the invention will be described.

The entire time chart of FIG. 3 shows at what timing the load turns on and off in accordance with the control command of the program of the microcomputer. 3 (A) shows the case where the combustor of the present invention is normal, that is, the case where the second diode 243 of the second constant voltage output circuit 245 shown in FIG. 2 is normal, and FIG. 3 (B). Is the second diode 243
Indicates an abnormal case. First, FIG. 2 (A) (f)
Shows the operating state of the second flame detector (hereinafter abbreviated as CdS _M 33). That is, it indicates that the combustor is in an on-off cycle combustion state in which it is repeatedly turned on and off ((a) is on, (b) is off, (c) is on, etc.) in a relatively short cycle (several seconds to tens of seconds). ing. FIGS. 2 (A) and 2 (a) show timings at which an operation switch (hereinafter referred to as operation SW81) of the remote controller for operating the remote controller 231 is turned on.
Figures (A) and (b) are blower fan motors (hereinafter abbreviated as FM50)
Shows the state of turning on (operating state) when the operation SW81 is turned on, and FIGS. 2 (A) and (c) show the second igniter (hereinafter referred to as IT).
_M 32) is operated with a delay of about ₁ pre-purge time T ₁ after the start of FM 50, and thereafter, the operation of covering the on / off time of the operation of CdS _M 33 is repeated. 2 (A) and (d) are fuel supply pumps (hereinafter abbreviated as EP40).
However, after starting the IT _M 32, it started operation with a delay of about ₂ pre-ignition time T ₂ and stopped when the detection signal of CdS _M 33 turned off (that is, a signal indicating no flame was emitted), and then the same. It shows the situation of repeating. Further, FIG. 2 (A)
In (e), the second fuel supply opening / closing valve (hereinafter abbreviated as SV _M 34) is EP4.
It shows a situation in which the operation is started (valve open) with 0, the operation is stopped (valve closed) before the EP40 stops the operation, and the same thing is repeated thereafter. Furthermore FIG. 2 (A) (f), once started ignition activated slightly earlier time i.e. the earliest time postignition time T ₃ from the IT _M 32 is extinguished (originating flames there the signal), SV _M Immediately after the operation is stopped (valve closed) in 34, the operation is stopped (a signal indicating no flame is issued) when the flame disappears, and the same situation is repeated thereafter.

Next, the essential function of the present invention will be described with reference to FIGS. 2 and 3. First, the case where the second diode 243 of the second constant voltage output circuit 245 is normal will be described. On-off cycle of the combustor When the combustion time of the first cycle after the start of combustion has just elapsed (time t in the time chart of FIG. 3)
From the microcomputer 231 to the second microcomputer output section transistor 2
An OFF signal is output to 33, so the second relay 254 for driving SV _M 34 is turned off, the fuel supply on-off valve is closed, and after a short time T ₄ , the flame in combustion chamber 11 disappears and CdS _M 33 Emits a flameless signal. And EP40 is turned off at the same time when the flame-free signal of CdS _M 33 is transmitted (Fig. 3, (A)).
(E), (f), (d)).

Next, a case where the second diode 243 of the second constant voltage output circuit 245 is abnormal (that is, the second diode 243 is short-circuited or reversely inserted) will be described with reference to FIG. 3 (B). . Similar to the above, at the time point t in FIG. 3, an off signal is output from the microcomputer 231 to the second microcomputer output section transistor 233. At this time point, the EP 40 has the shape shown in FIG. 3 (A) (d). (As shown), the potential of the anode of the first diode 242 of the first constant voltage output circuit 244 (that is, the potential of the circuit point 249) becomes about 0.6 V, and thus the second constant voltage output circuit 245 of the second The cathode potential of the diode 243 (that is, the potential of the circuit point 247) is about 0.6 V (in this case, the second diode 243 is in the abnormal state as described above).
Or it will be 1.2V. Therefore, the second relay 254 that drives the SV _M 34 is not turned off despite the off command of the microcomputer 231, the SV _M 34 remains open, and the flame in the combustion chamber 11 remains unextended. Become. Then, the microcomputer 231 receives the flame detection signal from the CdS _M 33, and determines that the flame is not extinguished as abnormal. That is, if CdS _M 33 does not send a flame-free signal within 5 seconds after the microcomputer 231 issues an off command to the SV _M 34 via the second microcomputer output unit transistor 233, the microcomputer 231 is It is determined that the second diode 243 is abnormal (above, refer to FIG. 3 (B)). In the present embodiment as described above, it is possible to detect the abnormality of the second diode 243 associated with the SV _M 34.

In the microcomputer 231, if, when the EP40 and SV _M 34 was built combustor control programs like turned off at the same time, can not be detected whether there is an abnormality in the aforementioned second diode 243, in this embodiment, SV _{Since the} combustor control program that turns off _M 34 earlier than EP 46 is installed and the control is executed as described above, as described above, whether or not there is an abnormality in the second diode 243 (hence the fixed value). It is possible to detect whether there is an abnormality in the voltage output circuit) and to monitor whether or not the load to be controlled is reliably turned on and off, which is the effect of this embodiment.

In the present embodiment, the case where the constant voltage output circuit for supplying constant voltage power to the relay circuit is two circuits, that is, the case where the presence or absence of the abnormality of the second diode is detected when the first and second diodes are provided has been taken up. Even if there are three or more constant voltage output circuits, the state of the load is monitored by CdS _M or other means by the same method as that used in the present embodiment, thereby checking whether or not there is an abnormality in the diode in each circuit. The presence / absence of an abnormality in each circuit can be detected, and it can be checked whether or not each load to be controlled is accurately turned on / off.

<Effect> The present invention is configured as described above, and according to the combustor failure detection device of the first aspect, the microcomputer in the device first causes the fuel to flow when the combustion time of the first cycle elapses with the start of the on-off cycle combustion. If the flame non-detection signal from the flame detector does not reach the microcomputer even after a certain period of time has elapsed after the closing signal of the supply on-off valve was output, the microcomputer supplies a constant voltage to the second relay circuit for driving the fuel supply on-off valve. It can be clearly determined that the second diode in the second constant voltage output circuit that outputs electric power is faulty (that is, short-circuited or reverse-inserted). Therefore, if the combustor failure detection device of the present invention is used, as described above, whether the diode of the constant voltage output circuit is normal is monitored by monitoring the load state by the input from the flame detector to the microcomputer. Whether or not the constant voltage output circuit is normal can be detected, and whether or not the load to be controlled is turned on and off can be monitored by the detection result.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an oil water heater showing a case in which a failure detection device for a combustor of the present invention is used to detect a failure of an oil water heater, and FIG. 2 is a circuit diagram in a controller of an embodiment of the present invention. , Third
FIG. 4 is a time chart showing the operation of this embodiment, and FIG. 4 is a circuit diagram showing a conventional example. 30: Burner 33: Flame detector 34: Fuel supply opening / closing valve 40: Fuel supply pump 210: DC power supply circuit 220: Voltage monitoring circuit 231: Microcomputer 242: First diode 243: Second diode 244, 243: First and second 2 constant voltage output circuits 257, 258: first and second relay circuits

Claims (1)

[Claims] 1. At least a burner having a fuel supply on-off valve and a flame detector, and a common fuel supply pump for sending oil to the burner via the fuel supply on-off valve. A combustor failure detection device for instantaneously supplying hot water of a temperature set by on-off cycle combustion that repeats on-off in a relatively short cycle, and drives a DC power supply circuit and at least the fuel supply opening / closing valve. A second relay circuit, a first relay circuit connected in parallel to the circuit, and a parallel-connected first constant voltage output circuit and a second constant voltage output connected in parallel to each of the first and second relay circuits. Circuit and constant voltage power output from the first constant voltage output circuit and the second constant voltage output circuit by inputting an operation switch signal to the first relay circuit and the second relay circuit. Inputting a DC voltage output from the DC power supply circuit, and a microcomputer for applying the constant voltage power to the second relay circuit by inputting a flame non-detection signal from the flame detector And a voltage monitoring circuit for supplying constant voltage power to the first constant voltage output circuit and the second constant voltage output circuit while supplying power to the microcomputer by using the first constant voltage output circuit and the second constant voltage. The output circuit includes a first diode and a second diode that are mutually connected on the anode side, and the microcomputer first closes the fuel supply opening / closing valve when the combustion time of the first cycle accompanying the start of the on / off cycle combustion elapses. A constant voltage output circuit for outputting a second relay circuit applied voltage application stop signal for operating and not inputting a flame non-detection signal from the flame detector even after a certain period of time. Second diode combustor malfunction detection system, wherein a is configured to determine as being or vice inserted shorted.