JPS59231325A - Ignition controller for gas utensil - Google Patents

Abstract

PURPOSE:To provide a device which, when failure in ignition occurs a given number of times, prevents an ignitor from ignition following said failure in ignition by deciding that the cause of the failure in ignition is not temporary, by a method wherein an ignition preventing means is operated by means of the output of a failure in ignition storing circuit produced due to a given number of times of failure in ignition to prevent further ignition of an ignitor. CONSTITUTION:A failure in ignition storing circuit 17 for storing the number of times of failure in ignition and an ignition preventing means 18 for preventing operation of an ignitor 6 are provided. An ignition preventing means 18 is constituted such that a second timer circuit 19, which, when ignition is made due to failure in ignition before the preventing means 18 is operated, is actuated to stop operation of an ignitor 6 for a time shorter than the time limit operating time of a first timer circuit 15, is provided, a third transistor 20, being brought to an ON-state by means of a high level output, is connected in series to a second transistor 16, and a fourth transistor, which is located to prevent application of the high level output to the third transistor 20, is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition control device for a gas appliance such as a gas water heater.

Conventionally, this type of device is known in which the igniter is activated by detecting a misfire in the burner using a flame detection circuit, and the igniter is activated every time there is a misfire to restart the ignition. This makes it easier to use as there is no need to manually ignite the ignition, but if the cause of misfire is not a temporary one such as wind, for example nozzle clogging or force, it can also be used again. The ignition is automatically repeated, which is undesirable from a safety perspective.In order to eliminate this inconvenience, the present invention aims to eliminate this inconvenience by determining whether the cause of the misfire is not temporary when a predetermined number of misfires occur. The purpose of this device is to provide a device that prevents subsequent re-ignitions by considering the number of misfires. A misfire memory circuit for storing the igniter and ignition prevention means for inhibiting the operation of the igniter are provided, and the means is activated when a predetermined number of misfires occur based on the output from the memory circuit. shall be.

The present invention will be explained below with reference to the illustrated embodiments.

The drawings show an embodiment in which the present invention is applied to a gas water heater.
i, (31 indicates a pilot nozzle, gas is supplied to the pilot nozzle (3) through the main solenoid valve (4) and no pilot solenoid valve (5), and the igniter (6) ) The pilot burner (3) is ignited by continuous sparking at the ignition electrode (6a) due to the energization of the main solenoid valve (4).
Gas was supplied through the first and second solenoid valves (71 (81) and each gas governor (9) to provide ignition from the pilot burner (3).

FIG. 2 shows the control circuit, and in the figure, a indicates a power switch, and a main solenoid valve ( 4) and the pilot solenoid valve (5), and also connect the igniter (6) via the normally closed B contact of the second relay switch r2, which will be described later, and the normally open state of the relay switch r2. Capacity selector switch a via contact a
The first and second solenoid valves (71 (81) incorporating υ are connected to the operating circuit of the first and second solenoid valves (71 (81),
) is opened to burn only the small burner (1), a medium capacity state is to open the second solenoid valve (8) and burn the large burner (2), and both solenoid valves ( 71 (81) can be freely switched to a high capacity state where both burners (1) (21) are burned by opening the valve. In the drawing, Oz indicates the pilot burner (3).
) shows a flame detection circuit that generates a high level output when ignition occurs and a low level output when a misfire occurs in response to a signal from the flame rod α3 facing the flame rod α3, A first transistor (14) that is turned on by a level output is connected in series, and the second relay R
The relay switch r2 of No. 2 is configured to be switched to the a contact side at the time of ignition and to the b contact side at the time of misfire, so that the energization operation of the igniter (6) is given in the event of a misfire.

In addition, it is not desirable for the igniter (6) to operate indefinitely without causing ignition in the event of a misfire, so in the case of the one shown in the figure, the ignition operation time is limited to a certain level, so that the output of the flame detection circuit side is - A first timer circuit 09 is provided that starts a time-limited operation upon a change to the level;
A second transistor on the output side of R1 is connected in series to the first relay horse, and when a certain period of time has elapsed without ignition occurring after a misfire, the first relay R1 is de-energized and the relay switch R is turned off. Then, the igniter (6) was stopped.

To explain this in more detail, the first timer circuit (151 is
When the output of one flame detection circuit a is high level, it continuously generates a high level output, and the second transistor (16)
is kept on, but when the output of the detection circuit (121) changes to low level, it outputs high level for a predetermined period of time, for example, 25 seconds, twice with a pause of 1 to 3 seconds before each output. If the ignition occurs and ignition is not performed within the time limit operation time of approximately 55 seconds in total, the function is to stop the operation of the igniter (6) as described above.

However, with only the first timer circuit α9, if ignition is performed within the time limit operation time, re-ignition will occur every time there is a misfire, regardless of the number of misfires, and in general, repeating misfires many times is rare. In many cases, the cause is not caused by hypersensitivity, resulting in inconveniences in terms of safety.

Therefore, in the present invention, a misfire memory circuit αη that stores the number of misfires and an ignition prevention means α that prevents the operation of the igniter (6) are provided.
& is provided, and the means α mark is activated when a predetermined number of misfires occur according to the output from the memory circuit (L7), and the igniter (6) is activated when re-igniting due to a predetermined number of misfires.
This prevents this from occurring.

Further, in the illustrated example, in the event of re-ignition due to a misfire before the blocking means Oa is activated, a second timer circuit ? A timer circuit a9 is provided, and a third transistor 4, which is turned on by its high-level output, is connected in series with the second transistor, and the sixth transistor (
The ignition blocking means α& is constituted by a fourth transistor provided to block the application of a high-level output to the ignition block 2t).

To explain this in more detail, the second timer circuit (1G is a flame detection circuit (17J) which continuously generates a high level output to keep the sixth transistor on when the output of the flame detection circuit (17J) is at a high level. At the same time, when the output of the detection circuit az is at a low level, it operates to generate a high level output for a certain period of time by a time-limited operation, and then operates to generate a low level output, and also outputs a signal to the time setting input terminal (19a). For example, the time limit operation time corresponding to the first timer circuit a9 is initially set to, for example, 55 seconds, but by inputting an external signal, the time limit operation time is shortened by inputting an external signal. The time has now been shortened to 25 seconds.

Further, the misfire memory circuit aη detects a misfire by a change in the output of the flame detection circuit (12+) from a high level to a low level, and stores the number of misfires. The first output terminal (1
7a) and generates a high level output to the transistor α.
When the first misfire occurs, a high-level output is generated at the second timer circuit (the second output terminal (17b) connected to the time setting input terminal (19a) of 11). 2
It operates to shorten the time limit operation time of the timer circuit Ql as described above.

In the drawing, Qυ indicates a water supply switch that is turned on when water is supplied to the water heater.

Next, to explain its operation, when water is supplied to the water heater with the power switch a1 turned on, the flame detection circuit IJ7J
The first and second timer circuits a9 depend on the low level output from the
α Yu starts time-limited operation, and the third transistor (a) is switched to 5 due to the high level output from the second timer circuit ([!l).
It is held on for 5 seconds and the first timer circuit C15
The high level output from 1 causes the second transistor (1
61 is kept on for 25 seconds 1 to 3 seconds after the start of water flow, then turned off for 1 to 3 seconds, and kept on again for 25 seconds.
Relay R1 is energized and its relay switch r is turned on, and the main solenoid valve (4) and pilot solenoid valve (5) are opened to supply gas to the pilot burner (3). The pilot burner (3) is ignited by energizing the igniter (6) through the normally closed b contact of the relay switch r2 of the second relay R2.

If the pilot burner (3) does not ignite during the 612 on-time period of the second transistor (161), the igniter (6) will not operate thereafter, but if the pilot burner (3) ignites during that time, the flame A high level output is generated from the detection circuit (121), and the first and second timer circuits (IFJ
A high level output is continuously generated from Ql, and the second and third transistors are turned on (1), so the relay switch r of the first relay is kept on, and the first transistor (141) of the first relay is also turned on. The second relay R2 is energized, and the relay switch r2 is switched to the normally open a contact to stop the operation of the igniter (6), and the first and second solenoid valves are switched on via the capacity changeover switch aυ. T71 (81 is opened, and the pilot burner (3) provides ignition to the small burner (1) and large burner (2).

After that, when a misfire occurs, the output of the flame detection circuit α2 changes from high level to low level, which turns off the first transistor (141) and switches the relay switch r2 of the second relay R2 to the b contact. The time-limited operation of the second timer circuit (15) (19) is started and the igniter (6
) starts igniting the pilet burner (3), but in this case, the misfire memory circuit (17) detects the first misfire and generates a high level output at its second output terminal (17b). As a result, the time limit operation time of the second timer circuit (19) is shortened to 25 seconds, and as a result, the sixth transistor A9 is turned off 25 seconds after the misfire, and the second high level output is generated from the first timer circuit a9. Even if the first
Relay R1 is no longer energized, and thus, if the pilot burner (3) does not ignite even 25 seconds after the first misfire, the igniter (6) will not operate thereafter.

On the other hand, if the pilot burner (3) ignites during this period and then misfires again, the misfire memory circuit <17) detects the second misfire and generates a high level output at its first output terminal (170). , the fourth transistor serving as the ignition blocking means is turned on, and even when a high level output is generated from the second timer circuit (1!1G), the third transistor is not turned on, and energization of the first relay R1 is blocked. Then, the relay switch r remains turned off, preventing the igniter (6) from operating.

The above description has been made of the case where the present invention is applied to a water heater, but the present invention is not limited to this.In the above embodiment, a second timer circuit a1 is provided to reduce the ignition operation time step by step every time there is a misfire. However, the ignition prevention means (18) is activated when a predetermined number of misfires occur; however, it is also possible to omit the first and second timer circuit (11); in this case, the ignition prevention means (1gj
is composed of a second transistor (corresponding to the fifth transistor (a) connected in series with 1e), which is turned off after a predetermined number of misfires by the output of the misfire memory circuit aη.

As described above, according to the present invention, if a predetermined number of misfires occur, the ignition prevention means is activated by the output of the misfire memory circuit to prevent re-ignition, and as described above, re-ignition is repeated indefinitely every time a misfire occurs. It has the effect of reliably eliminating the inconveniences of the conventional type.

[Brief explanation of the drawing]

FIG. 1 is a gas circuit diagram of an example of a gas appliance to which the apparatus of the present invention is applied, and FIG. 2 is a Plutz diagram of the control circuit thereof. (6)...Ignition device α3...Flame detection circuit (17)...Misfire memory circuit αQ...Ignition prevention means patent Applicant: 2 people other than Rinnai Corporation

Claims (1)

[Claims] The igniter is activated by misfire detection by a flame detection circuit, and includes a misfire memory circuit that stores the number of misfires, and ignition prevention means that prevents the igniter from operating.
An ignition control device for a gas appliance, characterized in that said means is activated when misfires occur a predetermined number of times based on an output from said memory circuit.