JP2551299B2 - Boiler safety controller during momentary power failure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a hot water boiler, a steam boiler, and the like, in the event of an instantaneous power failure, that is, a momentary power failure (including a pseudo-instantaneous power failure), while ensuring safety, the interlock state is maintained. The present invention relates to a safety control device capable of automatically restarting operation without performing.

[0002]

2. Description of the Related Art Conventionally, in a hot water boiler or the like, when a momentary power failure, that is, a momentary power failure occurs (including a momentary voltage drop), if it is burning, the flame blows out, so it is detected. Then, an alarm such as a misfire was issued on the way, and the combustion was forcibly stopped to control the interlock. The momentary power outage includes a relatively long pseudo-instantaneous power outage due to chattering of the power switch, and an instantaneous power outage when the power source for the boiler in the cogeneration system is switched from the cogeneration power source to the commercial power source (or from the commercial power source to the cogeneration power source).

[0003]

When the interlock state as described above occurs, in order to cancel the interlock state and restart the operation of the boiler, a person goes to the boiler installation place and presses the operation switch of the boiler. It was necessary to operate it to reset the interlock state, and then turn on the operation switch again. Therefore, operability is poor, especially in a cogeneration system, frequent instantaneous power failure occurs when switching from a cogeneration power source to a commercial power source (or from a commercial power source to a cogeneration power source), and it is necessary for a person to go out and operate the operation switch each time. However, it required a very complicated work.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in the case of a momentary power failure, that is, an instantaneous power failure in a boiler, while ensuring safety,
It is an object of the present invention to provide a boiler control device which is capable of automatically restarting operation without being brought into an interlock state and which is excellent in safety and operability. That is, the present invention, the instantaneous power failure detection means for detecting a momentary power failure based on the voltage value of the power supply line, and when the momentary power failure is detected, the combustion is forcibly stopped and the combustion standby state is set, After recovering from the momentary power failure, scavenging the inside of the combustion chamber for a predetermined time , at the end of scavenging, if there is a heat request signal, start combustion, and if there is no heat request signal, wait for combustion
Is characterized by comprising a combustion control means shall be the.

[0005]

According to the above construction, when a momentary power failure, that is, an instantaneous power failure, is detected by the instantaneous power failure detection means,
Combustion is forcibly stopped and the combustion standby state is set,
After the momentary power failure is restored, the combustion chamber is scavenged and combustion is started on the condition that there is a heat request signal, so the safety is ensured and the operation is automatically restarted without the interlock state. .

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. 2, the control unit consists of microcomputers (1), the regulated power supply unit (1A) and the detection unit (1B)
And that is configured from a relay operation unit and (1C). The relay operation part (1C) consists of the water supply pump (WP), blower (FM), igniter (IG),
Controls the fuel valve (VQ). For example, if there is a heat request signal, the heat request detection switch (2) described later will close and the control unit
(1) controls combustion according to a predetermined processing procedure. That is,
After driving the blower (FM) that sends combustion air and performing pre-purge for a predetermined time, open the fuel valve (VQ) and drive the igniter (IG) to start the ignition operation, and after confirming ignition, steady combustion Move to. The detection section (1B) functions as an instantaneous power failure detection means that monitors the voltage value of the power supply line (3) and detects an instantaneous power failure based on the voltage value. When the instantaneous power failure is detected, the fuel valve (VQ) and the like are controlled according to the control procedure for the instantaneous power failure shown in FIG. In addition, the control circuit shown in the figure
Includes a commercial power source (4), power switch (5). Heat demand detection switch that opens and closes depending on the presence or absence of heat demand (2)
Is (in the case of steam boiler steam pressure) top temperature of hot water in the can body (not shown) detects the open and close in accordance with the detection value.

Next, the operation of the present invention will be described with reference to FIG. The power supply line (3) by the detection unit (1B) in step S1
Monitor voltage. Here, it is monitored whether the power supply voltage has dropped below a predetermined value. In step S2, it is determined whether or not a power failure has occurred during combustion. Here, when the power supply voltage is equal to or lower than the predetermined value, the set time T1, for example, 0.02 sec
If it continues, it will be judged as a power failure. If YES is determined here, the process proceeds to step S3 to forcibly put the boiler into the combustion standby state. The combustion standby state is a state in which the fuel valve (VQ) is closed, the blower (FM) is stopped, the combustion is temporarily stopped, and it is possible to shift to the ignition operation when there is a heat request.
Then, in step S4, the power failure is set time T2 (> T1)
For example, it is determined whether or not it has continued for 0.2 sec or more. N
If it is determined to be O, the process proceeds to step S5, and after memorizing that the "instantaneous power failure during combustion" has occurred (displaying that the instantaneous power failure has occurred on the display), the blower (FM) is driven in step S6. Purge (scavenging air in the combustion chamber) for a predetermined time, for example, 7 seconds.

Next, in step S7, it is determined whether or not there is a heat request. This is done by detecting whether the heat demand detection switch (2) is open or closed by the detection unit (1B). If there is a heat request, the ignition operation is started in step S8 and combustion is started. In this way, if there is an instantaneous power failure during combustion, the fuel valve (VQ) is closed and the combustion standby state is set, and after purging, the combustion is transitioned according to the heat demand, so combustion control can be performed safely. It can be carried out. If NO is determined in step S7, the combustion standby state is set. still,
If NO in step S2, step S7
Move to.

If YES is determined in step S4, the process proceeds to step S10, and it is determined whether the voltage to the CPU of the control unit (1) is less than or equal to a preset operating voltage value. For example, if the normal voltage value is 5V, the determination value is set to 4.75V. If YES is determined here, it is considered to be a true relatively long power failure, and the process proceeds to step S11 to reset the microcomputer. In the case of a long-term power failure, it is unfavorable for safety to shift to combustion when there is a heat demand, so such control is performed. If NO is determined in step S10, the process proceeds to step 12 and the set time T3 (> T
2) For example, it is determined whether the power supply voltage is restored within 0.5 seconds. If YES is determined here, it is considered that chattering of the power switch (5) is caused, but after shifting to step S13 and performing the purging for a predetermined time, shifts to step S7, and the same control as described above is performed. .
In this way, even in the case of a pseudo relatively long instantaneous power failure due to chattering of the power switch (5), steps S4 to S9 are performed.
Similar to the relatively short instantaneous power failure of (1), the fuel valve (VQ) is once closed to put it in the combustion standby state, and after purging, the combustion is shifted to the heat demand.

If it is determined NO in step S12, the process proceeds to step S14. In this case, the power switch (5)
Is determined to be in the OFF state, and the operation stop process is performed.
The operation stop means a state in which combustion is not started even if there is a heat request.

Next, another embodiment of the present invention will be described with reference to FIG. Normally, the cogeneration power supply (6) obtained by waste heat recovery is used as the steam boiler power supply, and when the cogeneration power supply (6) cannot be used, the power supply switch
(7) configuration the system to use a power supply (4) for the quotient by switching, were subjected to measures against momentary power failure that occurs during power switching. The control circuit shown in the figure includes a DC power supply circuit (8), a relay operating circuit (9), and relay contacts (R
1), (R2), (R3), (R4) are provided. The heat demand detection switch (PS) that opens and closes depending on the presence or absence of a heat demand opens and closes according to the value of the steam pressure in the can body (not shown ) of the steam boiler. The momentary power failure detection relay (X) works to close the contact (X1) when energized and to open the contact (X1) when de-energized . Blackout
The detection timer (T) closes the contact (T1) by energization, and when the set time (eg 0.2 sec) elapses after the energization is stopped, the contact
(T1)-out open, an action for detecting a power failure is not an instantaneous.

The operation of this embodiment will be described below. When the power switch (7) is switched to the cogeneration power supply (6) side, the contacts (X1) and (T1) are closed, and when the heat demand detection switch (PS) is closed, the relay operation circuit (9 )
Is a blower (F
After M) is driven and pre-purge is performed for a predetermined time, the fuel valve (IQ) is opened and the igniter (IG) is driven to start the ignition operation, and after confirming the ignition, the steady combustion is performed.

When the cogeneration power supply is stopped, the power source selector switch (7) is turned on from the cogeneration power source (6) side to the commercial power source.
When switched to the (4) side, the momentary power failure detection relay (X) is de-energized and the contact (X1) opens until it is re-excited by the commercial power supply (4). Therefore, the fuel valve (VQ) is closed and the combustion is forcibly stopped. After that, when the momentary power failure detection relay (X) is re-excited to close the contact (X1) and the heat request detection switch (PS) is in the closed state, the pre-purge is performed for a predetermined time and then the ignition operation is performed. If commercial power is not supplied to the instantaneous power failure detection relay (X) for some reason,
The contact (T1) opens when the time set by the power failure detection timer (T) 0.2 seconds has elapsed, and the supply of power to the control circuit is stopped.

When the power switch (7) is switched, electromotive force is generated by rotation of the blower (FM) due to inertia,
As a result, the excitation of the relay (X) is continued, so that de-excitation of the relay (X) by switching the switch (7) may not occur. In this case, since the boiler is continuously operated by the electromotive force of the blower (FM), safety is ensured. Further , instead of the commercial power source (4), a backup power source charged by the cogeneration power source (6) may be used.

[0015]

EFFECTS OF THE INVENTION Since the present invention is configured as described above, the combustion interlock state does not occur even if an instantaneous power failure or a pseudo-instantaneous power failure occurs, and the operation is automatically restarted if a heat request is made. In addition to providing a control device with extremely good operability, when an instantaneous power failure or pseudo-instantaneous power failure occurs, the fuel valve is closed once to put it in a combustion standby state, and then pre-purge is performed to perform ignition operation. It is also excellent in safety as it exists.

[Brief description of drawings]

FIG. 1 is a flowchart showing a main control operation in an embodiment of the present invention.

FIG. 2 is a circuit diagram showing an outline of a control circuit in one embodiment of the present invention.

FIG. 3 is a circuit diagram showing an outline of a control circuit in another embodiment of the present invention.

[Explanation of symbols]

 1 Control part 1A Stabilized power supply part 1B Detection part 1C Relay operation part 2 Heat request detection switch 3 Power supply line 4 Commercial power supply 5 Power supply switch 6 Cogeneration power supply 7 Power supply changeover switch 8 DC power supply circuit 9 Relay operation circuit WP Water supply pump FM blower IG Ignition device VQ Fuel valve X Instantaneous power failure detection relay T Timer for power failure detection X1 contact T1 contact

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masato Kira, 7th Horie Town, Matsuyama City, Ehime Prefecture, Miura Industrial Co., Ltd. (72) Inventor, Hideaki Ando, 7th Horie Town, Matsuyama City, Ehime Prefecture, Miura Industrial Company (( 72) Inventor Keiji Hino 7 Horie-cho, Matsuyama-shi, Ehime, Miura Kogyo Co., Ltd. (72) Inventor Go Yoneda 7 Horie-cho, Matsuyama-shi, Ehime, Miura Kogyo Co., Ltd. Inspector, Katsuyuki Higashi (56) References JP-A-62-108926 (JP, A) JP-A-61-72927 (JP, A) JP-A-55-43361 (JP, A) JP-B-51-3092 (JP, B2)

Claims (5)

(57) [Claims] 1. A momentary power failure detection means for detecting a momentary power failure based on a voltage value of a power supply line, and when a momentary power failure is detected, the combustion is forcibly stopped to enter a combustion standby state, after power recovers, performs scavenging of the predetermined time the combustion chamber, at the scavenging completion, when the heat demand signal is present to initiate combustion, that if the heat demand signal is not provided with a combustion control means shall be the combustion standby state The feature is a boiler safety control device during momentary power failure. 2. The boiler safety control device for a momentary power failure according to claim 1, wherein a control circuit for the fuel valve is provided with a contact (X1) which opens and closes according to an output signal of the instantaneous power failure detection means. A safety control device for a boiler in the event of a momentary power failure. 3. The safety control device for a boiler in the event of a momentary power failure according to claim 2, wherein a commercial power source (4) is connected to the fuel valve control circuit and a cogeneration power source (6) is connected to the power circuit. A safety control device for a boiler in the event of a momentary power failure, which is switchably connected to a commercial power supply (4). 4. The boiler safety control device according to claim 2, wherein the fuel valve control circuit is connected to a backup power source, and the power circuit is connected to a cogeneration power source (6) and a backup power source. A safety control device for a boiler in the event of a momentary power failure, characterized in that it is switchably connected to a power source. 5. The boiler safety control device according to claim 2, wherein the fuel valve control circuit is provided with a contact (T1) which is closed by the start of energization and opened after a lapse of a predetermined time from the stop of energization. A safety control device for a boiler in the event of a momentary power failure.