JP2564961Y2 - Combustion safety device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion safety device for safely controlling the operation of a combustion device at the time of ignition.

[0002]

2. Description of the Related Art In a combustion safety device called a protection relay used in a conventional combustion device such as a boiler,
Is controlled by the ignition sequence as follows is performed when the ignition.
When there is an ignition operation by an ignition switch or the like, or a combustion request by a thermostat, first, a pre-purge is performed by turning a fan for a predetermined time to drive out residual gas in the combustion chamber. Next, the ignition operation is performed for a certain time by opening the pilot valve and operating the ignition. As a result, when the burner is ignited and a flame signal detecting the flame is obtained, a post IG for continuously performing the ignition operation for a certain period of time , that is,
After stabilizing the fire, open the main valve to start steady combustion.

If a flame signal is not obtained during the above-mentioned ignition operation for a predetermined time, an alarm is issued as ignition failure and the combustion device is locked out. Also, if a misfire occurs halfway after a flame signal is obtained once by the ignition operation, an alarm is output and lockout is performed.

When the ignition is performed again after the lockout, the lockout is released by operating the reset switch, and then the above-described ignition sequence is repeated. In a combustion device using gas as a fuel, lockout is usually performed after one ignition failure. For example, when the temperature is low such as in the morning of winter or when the piping is long, the lockout is performed once. of
It may be difficult to successfully ignite in the ignition operation .

[0005] For this reason, the standards of the combustion apparatus have recently been reviewed, and a standard has been established which permits a retry operation for performing the above-described sequence only once when ignition fails once.

[0006]

In the above-described combustion safety device which performs the retry operation, the ignition failure is reliably detected only once, and a retry signal for performing the retry operation is output. In the case of failure or misfire in the middle, it is important to ensure that a retry signal is not output by mistake from the viewpoint of ensuring safety.

The present invention has been made to solve the above-described problems, and has as its object to obtain a combustion safety device that reliably performs a retry operation when misfiring and does not perform a retry operation when a failure occurs. .

[0008]

In order to solve the problems] For this invention, fuel
In the ignition control of the fire safety device, the ignition control
Number of ignition operations and alarm signal to perform
The output circuit detects misfiring and activates the ignition.
A means is provided for retrying the crop only once .

[0009]

[Action] After the ignition operation is continued for a certain time, an alarm signal is confirmed.
If the alarm signal is detected,
Can be confirmed as fire. This allows one retry operation
Done. As a result, after one ignition, the alarm signal
Even if detected, retry is attempted because the ignition operation has ended.
No action is taken. In other words, it is determined to be due to a failure etc.
I do .

[0010]

FIG. 2 is a block diagram showing a circuit configuration of a drive part of a combustion safety device, wherein 1 is a power supply, 2 is an ignition drive circuit, 3 is a pilot valve drive circuit, 4 is a main valve drive circuit, and K1 is a power supply. Relay switch for supply,
K2 is a relay switch for selecting whether to apply power to the ignition drive circuit 2 and the pilot valve drive circuit 3 or to the main valve drive circuit 4.

FIG. 1 is a block diagram showing a circuit configuration of a control portion of the combustion safety device. 5 is a pre-purge timer circuit for measuring a pre-purge time, and 6 is a circuit for measuring an ignition operation time.
An IG trial timer circuit that outputs a V / IG base signal to drive the relay switch K1, an alarm output circuit that outputs an alarm signal, and a frame sensor (not shown) that detects a burner (not shown) flame 9) a frame detection circuit for generating a frame signal from the detection signal obtained from
Is an input terminal of a reset signal for resetting each of the circuits 5-8.

Reference numeral 10 denotes a switch M for switching the relay switch K2 to drive the main valve driving circuit 4 for a predetermined time.
A main valve drive timer circuit for outputting a V signal, and 11 is a halfway misfire detection circuit.

Reference numeral 12 denotes a misfire detection circuit for detecting misfire based on the PV / IG base signal from the IG trial timer circuit 6 and the alarm signal from the alarm output circuit 7.
Is a latch circuit that outputs a retry signal only once in response to one misfire detection, and 14 is a pulse generation circuit that converts the retry signal into a pulse signal. Note that this pulse signal is equivalent to the above-mentioned reset signal,
Reset ~ 8. The frame signal obtained from the frame detection circuit 8 is, as shown by a bold line, the above-mentioned respective circuits 5.
~ 8,10,11. The latch circuit 13 and the pulse generation circuit 14 constitute a retry unit.

Next, the operation of the above configuration will be described. First, an operation in a case where ignition is performed normally by one ignition sequence will be described with reference to FIG. When a reset signal is applied to the input terminal 9 and an ignition operation is performed, first, the pre-purge timer circuit 5 is operated, and a fan (not shown) is driven for the measured time to perform pre-purge. When the pre-purge is completed, the IG trial timer circuit 6 is operated by the output of the pre-purge timer circuit 5 at that time, the "H" PV / IG base signal shown in FIG. 3 is output, and the relay switch K1 is closed. At this time, the PV / IG base signal is also applied to the main valve drive timer circuit 10.

As a result, in FIG. 2, the voltage of the power supply 1 is applied to the ignition drive circuit 2 and the pilot valve drive circuit 3 via the relay switches K1 and K2, and an ignition operation (IG trial) is performed. When the burner is ignited by this ignition operation, the flame detection circuit 8
Thus, the frame signal shown in FIG. 3 is obtained. The frame signal IG trial timer circuit 6 is added to the main valve drive timer circuit 10, thereby, PV / I G signal continues to "H".

The main valve drive timer circuit 10 includes a PV
/ When the frame signal is applied when the IG base signal is performed a predetermined time IG trials at "H", after the predetermined time post IG from that point, the MV signal of FIG. 3 to start the measurement Output. The relay switch K2 is switched by this MV signal, the voltage of the power supply 1 is applied to the main valve drive circuit 4, the main valve (not shown) is opened, and a series of ignition sequences is completed, and the PV / I
The G base signal becomes “L”. This results in steady combustion.

Next, the operation in the case of ignition failure will be described with reference to FIG.
This will be described with reference to FIG. When the IG trial timer circuit 6 outputs the PV / IG base signal of “H” for a certain period of time after the pre-purge, when the frame signal is added, the IG trial timer circuit 6 changes to “H”.
If the frame signal is not added within a certain period of time, the PV / IG base signal is set to "L" as shown in FIG. When the inverted PV / IG base signal (“H”) at this time is applied to the alarm output circuit 7, the alarm signal shown in FIG. 4 is output. At the same time,
From the IG trial timer circuit 6 to the misfire detection circuit
A PV / IG base signal which becomes H only for a certain period of time serving as a base of a trial timer is provided (turns on for a certain period of time during an IG trial).

The fact that the PV / IG base signal has become "L" and the alarm signal are detected by the misfire detection circuit 12, and it is detected that ignition has failed. This detection output is latched by a latch circuit 13, and this latch circuit 13 outputs a retry signal. This retry signal is converted into a pulse signal by the pulse generation circuit 14, and this pulse signal resets each of the circuits 5 to 8. With this reset,
Again, the sequence of FIG. 3 is retried, and ignition is performed.

When the ignition fails again by the retry operation as shown in FIG.
Is detected by However, the latch circuit 13 is configured to accept the detection output of the misfire detection circuit 12 only once, and the retry signal is not output from the latch circuit 13 even when the second detection output is applied. Therefore, each circuit 5-8
Is not reset and the combustion device is locked out as having failed.

As shown in FIG. 5, when a flame signal is obtained and post-IG is performed, and after the main valve is opened by the MV signal and the flame is lost halfway and the frame signal disappears, the main valve driving timer is used. The circuit 10 immediately goes to M
Invert the V signal. This is detected by the misfire detection circuit 11 together with the disappearance of the frame signal, and the detection signal is sent to the alarm output circuit 7. Since the PV / IG base signal is at L, this outputs an alarm signal and locks out.

FIG. 6 is a circuit diagram showing a specific configuration of the misfire detection circuit 12, the latch circuit 13, and the pulse generation circuit 14, and FIG. 7 is a timing chart showing the operation.
6 shows output waveforms at points A to F in FIG. In FIG. 6, the input terminal 15 receives the PV / I signal shown in FIG.
The G base signal is applied from the IG trial timer circuit 6. In the case of misfire by this IG trial, the alarm signal shown in FIG.
More added.

The PV / IG base signal is integrated by the resistor R ₅ and the capacitor C ₁ to form a waveform shown by B _{1 in} FIG. 7C, and is delayed until the period of the alarm signal. The waveform of the B1 is applied to the comparator 17 and compared with the power supply voltage and the resistor R _6, R ₇ obtained by dividing the reference voltage.
The alarm signal is also applied to the comparator 18 via the resistors R ₁ and R ₂ and compared with the reference voltage obtained from the resistors R ₃ and R ₄ .

The comparators 17 and 18 constitute the misfire detection circuit 12 shown in FIG. 1. When the input voltage is higher than the reference voltage, the output is set to "H". In this case, FIG.
The output of the comparators 17 and 18 is connected to the resistors R8 and R8 because the output of the comparators 17 and 18 has the same timing as that of the alarm signal of FIG.
9 to obtain a voltage having a waveform shown in FIG. 7D.

The waveform voltage D is applied to a comparator 19 constituting the latch circuit 13. The output of the comparator 19 is "H", and the output voltage is fed back to the input side via the resistor R15 connected to the output side. On the input side, the reference voltage is determined by the resistors R12, R13, R14 and the feedback voltage. The voltage is determined. In this state, the D waveform voltage (the output of the comparator 17 and the
Both outputs are "H") is applied, the output of the comparator 19 when this voltage exceeds the reference voltage Tatsuka rising to "L" as shown in FIG. 7E, with the output becomes a retry signal, thereby The reference voltage is changed. Sand
Chi, comparator 19 performs a hysteresis operation, Lito
After the lie signal is output once, the output of the comparator 19 holds "L" regardless of the input voltage applied from the comparators 17 and 18 thereafter.

When the output of the comparator 19 falls to "L", this output becomes "H" after a certain time due to the time constant of the capacitor C2 and the resistor R17 which constitute the pulse generating circuit 14 via the resistor R16. As a result, a negative pulse signal shown in FIG. 7F is obtained. This pulse signal resets each of the circuits 5 to 8 in FIG. 1, and the ignition sequence is repeated.

Thereafter, due to misfiring due to a failure, misfiring, or the like, a PV / IG base signal or an alarm signal is again applied to the input terminals 15 and 16 and these signals are applied in any combination to make the above D No matter how the waveform voltage changes, the output of the comparator 19 holds “L”. Therefore, the pulse signal is output only once,
The ignition sequence is repeated only once.

[0027]

According to the invention, PV / IG as an IG trial signal for causing the ignition operation to be performed for a predetermined time is provided.
Misfire is detected based on the base signal and the alarm signal,
In response to this detection, a pulse signal is generated to perform a retry operation of the ignition sequence, and that misfire is performed only once,
Since the retry operation is not performed thereafter, the intended purpose can be achieved by preventing the retry operation from being performed in the case of misfiring due to a failure or misfiring in the middle, etc. Effects such as realization at low cost can be obtained only by adding a simple circuit.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a control portion of a combustion safety device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a driving portion of the device.

FIG. 3 is a timing chart showing the operation of the device at the time of ignition.

FIG. 4 is a timing chart showing the operation of the device when no ignition occurs.

FIG. 5 is a timing chart showing the operation of the apparatus when a misfire occurs halfway.

FIG. 6 is a circuit diagram showing a configuration of a main part of the device.

FIG. 7 is a timing chart showing the operation of the main part.

[Explanation of symbols]

 12 Misfire detection circuit 13 Latch circuit (retry means) 14 Pulse generation circuit (retry means)

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-318419 (JP, A) JP-A-60-181512 (JP, A) Jikai Sho 56-58154 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] 1. A sequence control for performing an ignition operation based on a reset signal for a predetermined period of time, shifting to steady combustion when ignition is detected by the ignition operation, and outputting an alarm signal when ignition is not detected during the predetermined period of time. Control at the time of ignition in the above combustion safety device
Is a misfire detecting circuit for detecting the misfire on the basis of the signal and the alarm signal for causing the ignition operation of the predetermined time, the reset signal equivalent in accordance with the detection output of the misfire detecting circuit The pulse signal is output once , and the pulse signal is output only once.
A combustion safety device comprising retry means for preventing the pulse signal from being generated even in response to the output of a fire detection circuit .