JPH0418209B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a control device for combustion equipment such as a space heater or water heater, and in particular is equipped with a safety function to stop fuel supply when the equipment overheats or falls over. This relates to a control device.

[Prior Art] Combustion appliances such as gas stoves and fan heaters are equipped with several safety functions using microcomputers, etc. However, due to abnormal control of the microcomputer, etc., the combustion state becomes abnormal and overheats. In order to ultimately ensure safety in the event of an accident or the equipment falling over, overheat switches and overturning switches are installed. When such an abnormality occurs, the power circuit of the combustion equipment is opened and operation is stopped, and the fuel is turned off. Supply and combustion have been stopped.

[Problem to be solved by the invention] However, if the power to the combustion equipment is cut off due to overheating, etc., and the operation is stopped, no display will be displayed even if the equipment is equipped with a display function. Therefore, there is a problem in that the user cannot determine the cause of the combustion stoppage.

The present invention is designed to reliably stop the fuel supply and stop combustion when an abnormality occurs in combustion equipment equipped with safety functions such as overheat switches and overturn switches that detect the occurrence of abnormalities. An object of the present invention is to provide a control device for combustion equipment that has a display function that can display that the safety function of the combustion equipment is operating.

[Means for Solving the Problems] The present invention is provided in a fuel supply path that supplies fuel to a burner, supplies fuel to the burner when energized, and stops supplying fuel to the burner when not energized. It has a solenoid valve, an energizing circuit that energizes the solenoid valve in response to a control signal from a valve control means, and a contact point connected in series with the solenoid valve in the energizing circuit. a circuit opening means that opens to stop power supply to the solenoid valve; an opening detection means that detects that the circuit opening means has opened the contact; and an opening detection means that detects that the contact has opened. energization stopping means that controls the energization circuit to stop energizing the solenoid valve when
A technical means is adopted comprising a display means for displaying a message to that effect when the open detection means detects that the contact is opened.

[Operation] According to the present invention, when an abnormality is detected by the circuit opening means, a contact point in the solenoid valve is opened and power supply to the solenoid valve is stopped.

Further, when the circuit opening means opens the contact, it is detected by the open detection means, and the energization stopping means stops energizing the electromagnetic valve by the energizing circuit.

Therefore, if an abnormality is detected while the solenoid valve is energized, the energization to the solenoid valve will continue to be stopped.
Combustion is stopped and fuel supply is continuously cut off.

Further, since an open detecting means is provided to detect the contact state of the circuit opening means provided in the energizing circuit to the solenoid valve, the display means is displayed based on the information detected by the open detecting means. Therefore, it is displayed that an abnormality has been detected.

[Effects of the Invention] In the present invention, the circuit opening means has a contact point connected in series with the solenoid valve in the energizing circuit to the solenoid valve, and can directly open the energizing circuit.
Even if the circuit opening means senses an abnormality due to abnormal operation of the valve control means, the supply of fuel to the burner can be reliably stopped.

In addition, even if the circuit opening means opens the contact, the current to the solenoid valve is only stopped and does not affect the current to other parts, so even if the contact opens, the open detection means Based on the information detected by the display means, the display means displays that an abnormality has been detected.

[Example] Next, the present invention will be described based on an example shown in the drawings.

The gas hot air heater 1 shown in FIG.
A heater main body 20 equipped with a gas supply path 30,
It is composed of a control device 40.

This combustor 10 is of a forced air type that sucks air from outside with a combustion fan 11 and supplies it into the combustor 10. The combustion exhaust gas combusted by the burner 12 passes through a heat exchanger 13 and is exhausted. It is exhausted from the port 14 to the outside. A sparker 15 for ignition is provided near the burner 12, and a thermocouple 16 for detecting the temperature of the flame is provided, and a signal thereof is sent to a control device 40.

The heater main body 20 uses a convection fan 21 for circulating hot air indoors to introduce indoor air from an air inlet 22, and exchanges it with high-temperature combustion gas passing through the heat exchanger 13 of the combustor 10. perform heat exchange,
The hot air is sent into the room from the hot air outlet 23.

The gas supply path 30 is a gas pipe 31 that supplies fuel gas supplied from a fuel supply source (not shown) into the combustor 10 . This gas pipe 31 is provided with a main solenoid valve 32 and a main solenoid valve 33 from the upstream side, and further downstream is a governor valve 34 that supplies fuel gas at a constant pressure, and a governor valve 34 that controls the supply amount of fuel gas according to the current. A proportional valve 35 is provided to adjust the proportional valve 3.
5, the upstream and downstream are connected by a bypass pipe 36,
An orifice 37 is provided in the bypass pipe 36 to allow a constant flow of fuel gas to pass therethrough.

The fuel gas that has passed through the gas supply path 30 is passed through a nozzle 38 provided in the outside air introduction path 17 of the combustor 10.
is supplied into the combustor 10 from.

The control device 40, as shown in FIG. The unit is also equipped with an operation switch (not shown), a combustion temperature thermistor, a hot air thermistor, and a temperature control volume.

The safety circuit 50 is a safety means of the present invention, and the safety circuit 50 is a safety means of the present invention.
0 to control the solenoid valve energization circuit 60. The safety circuit 50 includes a timer for energizing the solenoid valve for a predetermined period of time when the gas hot air heater 1 starts operating;
It consists of a flame detection circuit that generates a flame detection signal when a flame is detected, and an L level output signal to energize each solenoid valve only when operation is started and when combustion is being performed in the burner 12. Send out.

The solenoid valve energizing circuit 60 is the energizing circuit of the present invention consisting of the circuit shown in FIG.
1, 61a, and the contact points (not shown) of the relays 61, 61a are connected to the original solenoid valve 32 and the main solenoid valve 33.
are connected to each other, and the solenoid valve is energized when each relay is activated. The relays 61, 61a are transistors 62, 62a provided for switching.
It is energized only when an H level control signal is transmitted from the CPU 80 via the resistors 63 and 63a, respectively.

However, even when an H level control signal is transmitted from the CPU 80, each relay is not energized when the transistors 64 and 64a are turned on.

These transistors 64, 64a are switched by signals transmitted from the above-mentioned safety circuit 50 via resistors 65, 65a, and are set at the start of operation when safety can be ensured even if each solenoid valve is energized. Safety circuit 50 only during combustion in burner 12
It is turned off by the L level output signal of , and at this time, the transistors 62 and 62a are turned on and the relay is energized. Conversely, when an H level output signal is sent from the safety circuit 50, the transistors 64 and 64a are turned on. This lowers the base potential of each of the transistors 62 and 62a, so the transistors 62 and 62a are turned off.
Therefore, relays 61 and 61a are not energized.

The relays 61, 61a are energized by power supplied from a relay energization power source Va (not shown), but these relays 61, 61a are energized via an overheat switch (hereinafter referred to as OHS) 66 and an overturning switch 66a, respectively. and is connected to the power supply Va.

Both the OHS 66 and the overturning switch 66a are circuit opening means of the present invention. The OHS 66 opens a movable contact made of bimetal when the combustion temperature of the gas hot air heater 1 rises abnormally. On the other hand, the tipping switch 66a has fixed contacts electrically connected by mercury that are separated when the tipping switch 66a falls.

The display circuit 70 is a display means of the present invention that is equipped with an operation lamp, a combustion lamp, an overturning lamp, and an overheating lamp (not shown), and displays the operating state of the gas hot air heater 1 using electric power supplied from the power source Vb. These are displayed according to signals from the CPU 80.

A microcomputer (CPU) 80 is a valve control means of the present invention as well as an energization stopping means. When the operation switch is closed, the microcomputer (CPU) 80 starts operation in a predetermined sequence, controls the combustion state of the combustor 10, and controls the air flow in the burner 12. Fuel ratio control is also carried out, and the combustion fan 11 and the proportional valve 35 are controlled based on signals from the temperature setting volume and the thermocouple 16, respectively, to adjust the supply amount of combustion air and fuel gas, and the burner 12 adjusts the supply amount to the desired amount. Combustion takes place at an air-fuel ratio of .

Further, in this embodiment, when a danger such as when the combustor 10 overheats or when the gas warm air heater 1 falls over or the like is detected, the subsequent energization of each electromagnetic valve is stopped. This is because, in this embodiment, the OHS 66 and the overturning switch 66a open the circuit, which closes each electromagnetic valve and stops the fuel supply, stopping combustion, and as a result, the temperature decreases. Or, if the overturning condition of the gas hot air heater 1 is corrected normally, the OHS 66 or overturning switch 66a will close the circuit again and become energized. This is to prevent this. In this embodiment, these OHS 66 and the overturning switch 66a
A switching circuit 81 as an open detection means of the present invention detects that the contacts of each switch 66, 66a are open by detecting the voltage applied to the switch.
A switching circuit 81 detects the operation of these circuit opening means and transmits the signal.
It is being transmitted to CPU80.

When the signal is transmitted from the switching circuit 81, the CPU 80 inverts the H level output signal to the solenoid valve energizing circuit 60 to L level in order to stop energizing each solenoid valve. Further, when the CPU 80 sends an L level output signal to the solenoid valve energizing circuit 60, it simultaneously sends a control circuit signal to the display circuit 70 to light the corresponding display lamp.

Note that the CPU 80 and switching circuit 81 are
It is operated by power supplied from the power supply Vc.

The gas hot air heater 1 of this embodiment having the above configuration operates as follows.

When the power switch is turned on and the operation switch is closed, the combustion fan 11 is activated to supply combustion air into the combustor 10, the sparker 15 is activated, and the original solenoid valve 32 and main solenoid valve 33 are opened. state, and the proportional valve 35 is energized. Then, the burner 12 is ignited. Thereafter, when the thermocouple 16 detects the temperature inside the combustor 10, combustion air and fuel gas are supplied according to the temperature setting volume setting state. When the temperature of the combustor 10 rises due to combustion, the air introduced from the air inlet 22 by the convection fan 21 is heated by the heat exchanger 13, and is turned into warm air and sent into the room from the hot air outlet 23.

During combustion, if the combustion temperature rises due to abnormal combustion or if the gas hot air heater 1 falls over due to the user's carelessness, the OHS 66 or the fall switch 66a opens the electromagnetic valve energizing circuit 60, respectively.
Then, the relay 61 or relay 61a is de-energized and the contact is opened, so that the electromagnetic valve is de-energized.

At this time, OHS is output from the switching circuit 81.
66 or the overturning switch 66a is sent, and the CPU 80 stops the energization signal of each electromagnetic valve. At this time, the display circuit 70 is activated by the CPU 80, and the corresponding display lamp is lit. Combustion and fuel supply are therefore stopped, and the cause of the combustion stoppage is indicated by an indicator lamp.

As described above, in the present invention, when the overheat switch or overturn switch is activated due to an abnormality, the solenoid valve operates independently of the CPU and closes the solenoid valve, so if the CPU overheats due to abnormal combustion due to an abnormality. It is also possible to reliably stop fuel supply and combustion. In addition, in this embodiment, an overheat switch is used as a circuit opening means that opens the energized circuit when an abnormality is detected, so the bimetal may return when combustion stops, or the overturned state of the combustion equipment may be changed to normal by the user. Even if the respective circuits are closed again after being repaired, the power supply will continue to be stopped, ensuring safety.

Furthermore, when these circuit opening means operate to stop combustion, the cause of the combustion stop is displayed, so the user can easily know the cause.

FIG. 4 shows another embodiment of the solenoid valve energizing circuit 60. In the figure, the same numbers as in FIG. 3 indicate the same things.

In the above embodiment, the original solenoid valve 32, the main solenoid valve 3
Relays 61, 61a for energizing 3, respectively.
In this embodiment, as shown in FIG. 4, the OHS 66 and the overturning switch 66a are provided in series with the power supply Va. In the above embodiment, when either the OHS 66 or the overturning switch 66a is activated, only the solenoid valve connected to the power source Va through the first activated switch is closed, and then the signal from the CPU 80 is activated. Therefore, the other solenoid valve is also closed,
In this embodiment, when one switch is actuated, both solenoid valves are closed, and
Transistor 62 is controlled by a signal from CPU 80.
and 62a is turned off, and the energization of each relay is also stopped.

In this embodiment, a lamp is used for display on the display circuit 70, but a light emitting diode may also be used. Alternatively, an error code may be specified in advance for each switch and displayed using seven segments.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the operation of the control device of this embodiment, Fig. 2 is a configuration diagram showing the gas hot air heater of this embodiment, and Fig. 3 is a circuit showing an example of the electromagnetic valve energizing circuit. 4 are circuit diagrams showing other embodiments of the electromagnetic valve energizing circuit. In the figure, 32... Original solenoid valve, 33... Main solenoid valve,
60... Solenoid valve energizing circuit (energizing circuit), 66...
Overheat switch (circuit opening means), 66
a...Tipping switch (circuit opening means), 70...
Display circuit (display means), 80... Microcomputer (valve control means, energization stop means), 81...
Switching circuit (open detection means).

Claims (1)

[Scope of Claims] 1. A solenoid valve that is provided in a fuel supply path that supplies fuel to a burner, supplies fuel to the burner when energized, and stops supplying fuel to the burner when not energized, and valve control. an energizing circuit that energizes the solenoid valve in response to a control signal of the means; and a contact point connected in series with the solenoid valve in the energizing circuit, and when an abnormality is detected, the contact point is opened by itself to energize the solenoid valve. circuit opening means for stopping power supply to the circuit; open detection means for detecting that the circuit opening means has opened the contact; and opening detection means for opening the energized circuit when the open detection means detects that the contact has opened. A control device for a combustion equipment, comprising: an energization stopping means for controlling and stopping energization to the electromagnetic valve; and a display means for displaying when the opening detection means detects that the contact is open.