JPH0381048B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a combustion engine that is equipped with a combustion fan that supplies combustion air to a burner according to the output of a combustion detection element, and that an igniter and combustion supply means are activated after pre-purging. Concerning combustion safety devices for containers.

Conventionally, in this type of combustor, when the igniter and fuel supply means operate to perform ignition operation after the completion of pre-purge, the output of the combustion detection element cannot be obtained, so the volume of combustion air supplied to the burner is limited to the pre-purge. The airflow rate gradually decreases, and the air-fuel mixture changes from a gas-lean state to a gas-rich state relatively quickly, so there is a risk that, although it will ignite once at the time of the change in state, it will become gas-rich and misfire. Ta.

The present invention aims to eliminate such inconveniences in the prior art, and includes a combustion fan that supplies combustion air to the burner according to the output of the combustion detection element, and after the completion of pre-purge, an igniter and a fuel supply means. is configured to operate, a rotation speed command circuit outputting a rotation speed command signal of the combustion fan, a pre-purge timer circuit, an ignition rotation speed setting circuit, an ignition rotation speed confirmation circuit, and a A timer is provided to stop the operation of the ignition speed setting circuit when the ignition speed setting circuit is activated and stopped, and the speed command circuit outputs a prepurge rotation speed command signal by the prepurge timer circuit during the pre-purge, and after the completion of the pre-purge. During ignition operation, the ignition rotation speed setting circuit outputs a rotation speed command signal corresponding to the air volume suitable for ignition, and while the timer is operating after ignition, the ignition rotation speed command signal from the ignition rotation speed setting circuit outputs a rotation speed command signal corresponding to the air volume suitable for ignition. When it is larger than the number command signal, the ignition speed command signal is output continuously, when it is smaller, the rotation speed command signal is output according to the output of the combustion detection element, and after the timer operation stops, it is output according to the output of the combustion detection element. It is configured to output a rotation speed command signal,
The fuel supply means is characterized in that it operates when the ignition rotation speed confirmation circuit confirms that the rotation speed of the combustion fan has reached the ignition rotation speed.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic diagram of an embodiment of the invention. In the figure, 1 is a burner, and the burner 1
is connected to a fuel source (not shown) via a fuel passage 5 in which a proportional valve 2, a governor 3 and a solenoid valve 4 as fuel supply means are interposed. 6 is a combustion fan, a drive motor 7 of the fan 6 is connected to an AC power source 10 via a rectifier circuit 8 and a transistor 9, a control pole of the transistor 9 is connected to a differential amplifier circuit 11, The input terminal of the circuit 11 is connected to the rotation speed detection circuit 13 of the combustion fan 6 connected to the rotation speed pickup coil 12 of the drive motor 7 and the rotation speed command circuit 15 of the combustion fan 6 connected to the combustion detection element 14. The command signal output from the combustion fan rotation speed command circuit 15 in accordance with the output of the combustion detection element 14 and the combustion fan rotation speed detection circuit 1
The combustion fan 6, which is also driven by the drive motor 7, controls the transistor 9 with the output of the differential amplifier circuit 11 that differentially amplifies the output signal of the combustion detection element 1.
The amount of combustion air corresponding to the output of burner 4 is supplied to burner 1.

Further, a pre-purge timer circuit 16 and a combustion fan ignition speed setting circuit 17 are connected to the combustion fan rotation speed command circuit 15.
5 outputs a prepurge rotation speed command signal using the output signal of the timer circuit 16 during prepurge, outputs the output signal of the ignition rotation speed setting circuit 17 during ignition operation after the completion of prepurge, and outputs the output signal of the ignition rotation speed setting circuit 17 during prepurge. The combustion fan 6 uses an air volume that is larger than the air volume that corresponds to the maximum opening of the valve 2, and during ignition operation, an air volume that is suitable for ignition, that is, an air volume that is larger than the air volume that is suitable for combustion with only the bypass flow rate when the proportional valve 2 is closed. The air volume smaller than the air volume due to the maximum rotation speed is supplied to each burner 1. Also,
In the figure, 18 is an ignition rotation speed confirmation circuit that confirms that the combustion fan 6 has reached the above-mentioned ignition rotation speed, and the solenoid valve 4 is connected to the combustion fan 6 after pre-purging.
When the rotational speed of the engine reaches the ignition rotational speed, the valve is opened by the output signal of the circuit 18. Reference numeral 19 indicates an igniter that operates after completion of prepurge, and reference numeral 20 indicates a hot air fan.

FIG. 2 shows a detailed electrical circuit diagram of what is shown in FIG.

In FIG. 2, 21 is a forced strong combustion holding timer, this timer 21 is for outputting a signal to fully open the proportional valve 2 from the circuit 22 for one minute after the temperature control circuit 22 is activated, and 23 is an igniter. In the spark detection circuit 19, the circuit 23 is connected to an AND gate 24, so that when the circuit 23 is not operating, the proportional valve 2 is not opened by the output signal of the temperature control circuit 22. combustion fan 6
The ignition speed setting circuit 17 is connected to the power supply via a transistor 25, the control pole of the transistor 25 is connected to the output terminal of a timer 26, and the timer 2
6 is connected via an amplifier circuit 27 to an ignition detection circuit 28 connected to a combustion detection element, such as a thermocouple 14;
When ignited, a timer 26 is activated, and the transistor 25 is switched from on to off after a predetermined period of time has elapsed. Reference numeral 18 denotes a combustion fan ignition rotation speed confirmation circuit, which outputs a confirmation signal when the terminal voltage of the drive motor 7 or the output of the rotation speed pickup coil 12 reaches a value corresponding to the rotation speed of the air volume suitable for ignition. The solenoid valve 4, which serves as a fuel supply means, is opened when the combustion fan 6 reaches the ignition speed, the transistor 29 is turned on by the confirmation signal, and the contact 30a of the switch 30 is closed. It was to so.

Reference numeral 31 denotes a misfire determination circuit, and when the circuit 31 is activated, the transistor 32 is turned on, the contact 33a of the switch 33 is opened, and the solenoid valve 4 is closed. Also, the igniter 19 is connected to the contact 34 of the switch 34.
The switch 34 is connected to the DC terminal of the rectifier circuit 8 through the contact 34a when the transistor 35 is turned on by the output of the pre-purge timer circuit 16.
is now closed.

A transistor 36 is connected in parallel with the transistor 29 and is turned on by the output of the ignition detection circuit 28. When the transistor 36 is turned on, the solenoid valve 4 is kept open after ignition.

Next, the operation of the embodiment of the present invention will be explained.

When the main switch 37 is turned on, the transistor 38 is turned on by the output of the temperature control circuit 22.
The prepurge timer circuit 16 starts operating. The output from the circuit 16 activates the rotation speed command circuit 15, the combustion fan 6 rotates at a rotation speed suitable for pre-purge, and pre-purge begins. After a certain period of time, the output of the pre-purge timer circuit 16 becomes low level, and when the pre-purge is completed, the transistor 35 is turned on, the contact 34a of the switch 34 is closed, and the igniter 19 is activated. When the spark detection circuit detects the spark from the igniter 19, the temperature control circuit 2
Since 2 is outputting a high level signal, AND
Transistor 39 is turned on via gate 24, and proportional valve 2 is fully opened. When the pre-purge is completed, the output of the ignition rotation speed setting circuit 17 causes the drive motor 7 of the combustion fan 6 to decrease from the pre-purge rotation speed to the ignition rotation speed. When the ignition rotation speed is confirmed by the ignition rotation speed confirmation circuit 18, the transistor 29 is turned on, the contact 30a of the switch 30 is closed, and the solenoid valve 4 is opened. When ignition occurs here, the output of the thermocouple 14 increases, and when the output exceeds a certain value, the ignition detection circuit 28 outputs a high level signal, the transistor 40 is turned on, and the timer 26 operates to start timing. . Setting time e.g.
Since the transistor 25 is turned on by the output of the timer 26 for 32 seconds, the ignition speed setting circuit 17 continues to operate. Therefore thermocouple 1
When the output of the thermocouple 14 does not exceed a certain value (for example, 4mv), that is, when ignition is not performed, the combustion fan 6 continues to rotate at the ignition speed for a set time, and even after the set time has passed, the thermocouple 14 continues to rotate. If the output does not exceed a certain value, the ignition speed setting circuit 17 will be inactive and the combustion fan 6 will be below the ignition speed, so the flame will tend to lift and the thermocouple 1
The electromotive force of 4 decreases (for example, 17 mV), the misfire determination circuit 31 is activated, the transistor 32 is turned on, the contact 33a of the switch 33 is opened, and the operation of the combustor is stopped. Thermocouple 14 during the set time
When the voltage exceeds a certain value and the output of the amplifier circuit 27 exceeds the output of the ignition rotation speed setting circuit 17, the combustion fan 6 rotates in accordance with the output of the amplifier circuit 27, that is, the output of the thermocouple 14.

As described above, according to the present invention, when the post-prepurge igniter and the solenoid valve serving as the fuel supply means operate to perform ignition operation, the combustion fan is driven at an air volume suitable for ignition by the output of the air volume setting means. Therefore, unlike in the conventional case, the state does not change from gas lean to gas rich after completion of prepurge, and therefore there is no risk of misfire.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an embodiment of the invention;
FIG. 2 shows an electrical circuit diagram of what is shown in FIG. 1... Burner, 2... Proportional valve, 4... Solenoid valve,
6... Combustion fan, 7... Drive motor, 11...
Differential amplifier circuit, 13... Rotation speed detection circuit, 14...
... Thermocouple, 15 ... Rotation speed command circuit, 16 ... Prepurge timer circuit, 17 ... Ignition rotation speed setting circuit, 18 ... Ignition rotation speed confirmation circuit, 19 ... Igniter, 20 ... For hot air Fan, 22...Temperature control circuit, 26...Timer.

Claims (1)

[Claims] 1. In a device equipped with a combustion fan that supplies combustion air to the burner according to the output of the combustion detection element, and in which the igniter and fuel supply means are activated after completion of pre-purge, the rotation speed command signal of the combustion fan is An output rotation speed command circuit, a pre-purge timer circuit, an ignition rotation speed setting circuit, an ignition rotation speed confirmation circuit, and a timer that is activated when the burner is ignited and stops the operation of the ignition rotation speed setting circuit when the operation is stopped. During prepurge, the rotation speed command circuit outputs a prepurge rotation speed command signal using the prepurge timer circuit, and during ignition operation after the completion of prepurge, the ignition rotation speed setting circuit outputs a rotation speed corresponding to the air volume suitable for ignition. During the timer operation after ignition, if the ignition rotation speed command signal from the ignition rotation speed setting circuit is larger than the rotation speed command signal from the combustion detection element, the ignition rotation speed command signal is continuously output. is configured to output a rotation speed command signal according to the output of the combustion detection element when the timer is small, and output a rotation speed command signal according to the output of the combustion detection element after the timer operation is stopped, and the fuel supply means outputs a rotation speed command signal according to the output of the combustion detection element. A combustion safety device characterized in that it is configured to operate when a rotation speed confirmation circuit confirms that the rotation speed of the combustion fan has reached the ignition rotation speed.