JPS6330038Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a fail-safe recycling method that determines whether to restart the combustion controller when the combustor extinguishes the flame and select recycle operation, or to shut it off without restarting and select non-recycle operation.・Regarding non-recycle selection circuit.

Depending on the user's request, there are combustion control devices that restart the combustor when the flame is extinguished to perform a recycling operation, and combustion control devices that shut off the combustor without restarting it when the flame extinguishes, resulting in non-cycle operation. There is a device.

It would be wasteful for a manufacturer to separately design and manufacture two types of combustion control devices with different functions. Therefore, it is conceivable to make the electric circuit of the combustion control device common and to be able to select recycling or non-recycling using a switch connected to an external terminal.

However, if something that is set to recycle mode is changed to non-recycle mode due to some abnormality, it will stop safely, so it can be said to be fail-safe, but something that was set to non-recycle mode is changed to recycle mode due to some abnormality. It is dangerous to be exposed. In other words, the occurrence of recycling → non-recycling is acceptable, but the occurrence of non-recycling → recycling must be prevented.

It is an object of the present invention to provide a recycle/non-recycle selection circuit in which there is no room for such dangerous operations to occur.

In order to achieve the above object, the present invention has a state determination circuit 20 which introduces a heat request signal or a flame signal to output a start signal, introduces a flame extinguishing signal and outputs a stop signal, as shown in FIG. , if normal, the activation signal of the state determination circuit 20 is sent to the memory circuit 50.
and a combustion sequence circuit 90 that sequentially drives the fan 60, ignition circuit 70, and valve 80 in accordance with a predetermined sequence based on the set signal from the memory circuit 50.
The combustion controller 10 has a set terminal 11 connected to a changeover switch 35 that determines whether to perform a recycle operation or a non-cycle operation at the time of extinction, and a signal from the set terminal 11, an extinguishing signal, and the combustion sequence circuit. An AND gate 31 is provided which receives the prepurge end signal from 90 as input, the output terminal of the AND gate is connected to the reset terminal of the memory circuit, and a voltage is applied to the set terminal 11 to perform recycling. One contact m of the changeover switch is connected to ground, and the other contact n is connected to the voltage supply terminal, so that non-recycle operation can be achieved by not applying voltage to the set terminal 11. be.

Next, the effect will be explained. When the activation signal is output from the state determination circuit 20 due to the introduction of the heat request signal, the safety switch drive circuit 21 receives this activation signal and sets the memory circuit 50. Upon receiving the set signal from the memory circuit 50, the combustion sequence circuit 90 sequentially drives the fan 60, ignition circuit 70, and valve 80 according to a predetermined sequence to perform a combustion operation.

If the flame goes out during combustion and no voltage is applied to the set terminal 11, the AND logic of the AND gate will not hold and the memory circuit cannot be reset. However, the safety switch drive circuit is activated by the stop signal from the state determination circuit that receives the extinguishing signal, resulting in non-recycling.

Additionally, if the flame goes out while applying voltage to the set terminal, the memory circuit will be reset by the output of the AND gate, and the safety switch drive circuit will not work.
When the heat request signal is received again, recycling is repeated.

By configuring as described above, non-recycle does not become recycle, and fail-safe is realized.

The embodiments shown in the drawings will be specifically described below.

In the figure, the integrated combustion control section A and the external connection B are separated along the dashed line 10, and the integrated circuit casing 10 has terminals 11, 12, 13, 14, 15.
and 16 are drawn out from the control section A, respectively.

Inside the control unit A, input terminals 15 and 16 are connected to a state determination circuit 20, where:
Status signals from a thermostat and a flame detector (not shown) provided outside the integrated control unit A are input. 21 is a safety shutoff switch activation circuit;
2 is a latch circuit, 23, 24 and 26 are memory circuits, 28 is a prepurge timing timer circuit, 29 is an ignition trial timing timer circuit, 25, 27, 30 and 31 are AND gates, 32 is an OR gate, and 33 is a It is an S-R flip-flop.

In normal operation, when a heat request signal is received from a thermostat, that is, a start switch, the safety switch drive circuit 21 is operated momentarily, and the latch circuit 22 is activated.
The output 35 of energizes the timer circuit 28, and a signal _T0 indicating that the timer has begun to energize is applied to the status determination circuit 20, again locking the operation of the safety switch drive circuit. This one-cycle operation confirms that the drive circuit 21 can operate normally. After this confirmation, the latch circuit 22 sets the memory circuit 23 to "1". As a result, the initial value of the memory circuit 26 is set to M3=0, so
M3=1, and the output of the AND gate 25 is 1.
Therefore, the memory circuit 24 is also set to 1. Therefore, a signal for driving a fan motor (not shown) is output to terminal M, energizing relay 41 and transistor 40. When the prepurge timer 28 measures a predetermined prepurge time, a signal indicating the end of prepurge is given to the memory circuit 26, and an output V ₁ is sent to the terminal 13 via the AND gate 27, which connects the relay with the same configuration as the terminal 12. energizes and issues a signal to open the pilot valve. At this time, the ignition trial timer 29 is already counting time, and if ignition is established during this ignition trial, the timer output of the trial timer 29, which becomes 1 after the ignition trial ends, and the flame signal are input via the AND gate 30. The output that energizes the main valve V2 is connected to terminal 14.
and enters steady combustion.

Now, when the flame goes out during this normal combustion operation, S-R
The flip-flop 33 has a signal indicating extinguishment =
1 is given. On the other hand, since the states of the memory circuits 23 and 24 are already stored as "1",
The output of the OR gate 32 is "1", and this "1" signal is caused by the previous flame signal to cause the output of the S-R flip-flop, that is, the AND gate 31.
given to the input of The AND gate 31 has a memory circuit 2 which is already set to "1" as another input.
6 signal M3="1" is given.

Now, with the external connection, set terminal 11 is connected to switch 3.
5 is set to zero voltage through terminals 1 and m, and this state is selected for non-recycle operation. At this time, since the output of the AND gate 31 is "0", the reset output _R0 to the memory circuits 23, 24 and 26 is not provided.

Therefore, since the state of this memory circuit does not return to its original state, recycling does not start again.
Therefore, when the flame extinguishing signal is continuously input for a predetermined period of time, the driven safety switch circuit 21 is energized and the circuit is cut off. The safety switch circuit 21 may be composed of an IC timer or a bimetallic timer.

However, when a voltage +V is applied to the external terminal 11 via the terminals l and n of the switch 35, all the inputs of the AND gate 31 become "1", and "1" appears at its output. When this reset output _R0 becomes "1", the memory circuits 23, 24, and 26 become "0".
As a result, the control section returns to the initial state, and the heat request signal is applied from the start switch input terminal 15, and the operation starts again from the beginning.

Now, what is important in this invention is to eliminate malfunctions such as recycle operation even though the circuit is set for non-recycle operation in the external connection, especially when applying voltage to terminal 11. This is achieved by selecting non-recycle operation when no voltage is applied to the recycle operation. In other words, if you set non-recycle operation when applying voltage, if the voltage disappears for some reason, or if a break occurs in the conductor 34 or 36, the switch will change to recycle operation without you noticing. It is extremely dangerous.

In the present invention, by applying voltage to terminal 11 when selecting recycle operation and not applying voltage when selecting non-recycle operation, it is possible to completely prevent a failure that would result in recycle operation when non-recycle operation should be selected. It is preventable. That is, in this case, although a non-recycle operation may occur when a recycle operation should be performed, such a failure does not pose any particular danger because the circuit is interrupted.

As described above, the present invention has the advantage of being able to prevent dangerous failures due to its extremely simple configuration that only takes into consideration the voltage application to the recycle/non-recycle set terminals to the combustion control device.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the main parts of the selection circuit of the present invention, Figure 2
The figure is a circuit configuration diagram showing a specific embodiment of the present invention. In the figure, A... integrated circuit section, B... external circuit section,
11, 12, 13, 14, 15 and 16...terminals, 23, 24 and 26...memory circuit, 32...
...OR gate, 33...S-R flip-flop, 31...AND gate.

Claims (1)

[Scope of utility model registration request] A status determination circuit that introduces a heat request signal or a flame signal to output a start signal, introduces a flame extinguishing signal and outputs a stop signal, and a safety switch that sets the activation signal of the status determination circuit in a memory circuit if normal. A combustion controller that integrates a drive circuit and a combustion sequence circuit that sequentially drives the fan, ignition circuit, and valve according to a predetermined sequence based on the set signal from the memory circuit is configured to perform a recycle operation or a non-recycling operation when the fuel is lost. A set terminal connected to a changeover switch that determines whether to perform a cycle operation, and an AND gate that receives the signal of the set terminal, an extinguishing signal, and a pre-purge end signal from the combustion sequence circuit are provided, and the output of the AND gate is The terminal is connected to a reset terminal of the memory circuit, and a recycling operation is performed by applying a voltage to the set terminal, and a non-recycling operation is performed by not applying a voltage to the set terminal. A recycle/non-recycle selection circuit for a combustion controller, characterized in that one contact of the changeover switch is connected to ground, and the other contact is connected to a voltage supply terminal.