JPS5833405Y2 - combustion device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a combustion device that preheats a combustion cylinder in a combustor and then vaporizes and burns liquid fuel such as kerosene.

The circuit configuration of a conventionally known combustion device will be explained with reference to FIG. 1. In FIG. 1, 1 is an AC power source, 2 is a combustor including a heater for heating and vaporizing fuel, a combustion tube, etc. The combustor 2 is configured to be turned on and off by a contact 5a that opens and closes in conjunction with the operation of a relay 6, which will be described later.

3 is a DC power supply, and a series circuit having a resistor 4 and a thermistor 5 is connected to both ends of the DC power supply 30.
A series circuit including a relay 6 including a contact 6a connected in series between the AC power source 1 and the combustor 2, a transistor 7, and a thyristor 8 is connected, respectively.

The thermistor 5 detects the temperature of the combustion cylinder, and also includes a drive circuit (not shown) for energizing/deenergizing a preheater (not shown).
It has the function of a signal source (not shown).

9 is a hot water temperature adjustment circuit that detects the hot water temperature and controls the transistor 7 on and off based on the signal; 10 is a hot water temperature adjusting circuit that controls the thyristor 8 in response to the detection output of the thermistor 5 when the temperature of the combustion cylinder reaches the preheating temperature; ~ Rigger preheating temperature control circuit, 1
1 is a resistor connected in parallel to the series circuit of the relay 6 and the transistor 7, and the resistor 11 is for causing a holding current to flow through the thyristor 8.

In such a combustion apparatus, since the combustion cylinder in the combustor 2 is in a low temperature state when the star 1 is turned on, the heater is energized to a predetermined temperature set in the preheating temperature control circuit 10.

When this combustion tube reaches a predetermined temperature, that is, a preheating temperature, the preheating temperature adjustment circuit 10 receives the potential obtained by dividing the voltage of the DC power supply 3 by the resistor 4 and thermistor 5, and the thyristor 8
The thyristor 8 is turned on by applying a tonogager signal to the gates 1 to 1 of the thyristor 8.

At this time, the hot water temperature is also low, so the hot water temperature adjustment circuit 9 applies a forward bias to the base of the transistor 7 based on the output of the detected hot water temperature to turn on the transistor 7.

As a result, the relay 6 is activated by the current from the DC power source 3 to close the contact 6a, and the combustor 2 starts combustion.

At this time, the combustion tube receives combustion heat during combustion, so the power supply to the heater is cut off, and when the temperature falls below the preheating temperature, power supply to the heater is started.

Therefore, once preheating is completed, a holding current flows to the thyristor 8 via the resistor 11, so that the operation of the combustor 2 is controlled by the on/off state of the transistor 7 regardless of the temperature of the combustion tube, as shown in FIG. In other words, it is determined only by the temperature of the water.

However, in a combustion device configured in this way, once preheating is completed and the temperature of the combustion tube decreases (
For example, during short cycle operation), the liquid fuel cannot be sufficiently vaporized, resulting in a non-ignition phenomenon.

The present invention was developed to eliminate these drawbacks, and a switch circuit that operates at a combustion stop temperature, which is set lower than the preheating temperature, is connected in series to the transistor that controls on/off in the hot water temperature adjustment circuit. Another object of the present invention is to provide a combustion device in which the operation of the combustor is stopped by operating the switch circuit when the combustion cylinder temperature falls below the combustion stop temperature.

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 2 is a circuit configuration diagram showing one embodiment of the combustion apparatus according to the present invention. In the figure, the same parts as in FIG. 1 are designated by the same numbers and their explanations are omitted.

In FIG. 2, 12 is a switch circuit that is turned on when the combustion cylinder temperature is higher than a preset combustion stop temperature in relation to the detection output of the thermistor 5, and turned off when it is lower than that; This switch circuit 12 is composed of a transistor 13 and resistors 14 and 15.

In this case, the resistance values of the resistors 14 and 15 are selected so that the switch circuit 12 turns on and off the transistor 13 in accordance with the detection output of the thermistor 5 as described above.

Next, the operation of the above embodiment will be explained.

When the combustion tube is energized by starting, the voltage across the thermistor 5, that is, the detection voltage gradually decreases as the temperature of the combustion tube rises.

At this time, when the combustion cylinder is preheated, the thyristor 8 is triggered by a gate signal from the preheating temperature control circuit 10 and turned on, and the transistor 7 is turned on by the hot water temperature control circuit 9 in the same manner as described above.

A transistor 13 constituting the switch circuit 12
Since the combustion tube temperature is already higher than the combustion stop temperature, the combustor 2 enters the ON operating state and the combustor 2 starts combustion.

If the combustion tube temperature does not fall below the combustion stop temperature during this operation, a holding current flows through the thyristor 8 through the resistor 11 and the transistor 13, and this thyristor 8 maintains the holding state, so the operation of the combustor 2 is stopped. As in the past, it is controlled only by the temperature of the hot water related to the hot water temperature adjustment circuit 9.

However, when the temperature of the combustion tube falls below the combustion stop temperature during operation of the combustor 2, the resistance value of the thermistor 5 increases accordingly, and a reverse bias is applied to the base of the I transistor 13. Since the transistor 13 is turned off, the holding current of the thyristor 8 is cut off and the thyristor 8 is turned off, and the relay 6 is put into a non-operating state and the combustor 2 is stopped.

Therefore, when the combustor 2 is operated next time, the combustor 2 will not operate unless the combustion tube temperature is equal to or higher than the preheating temperature, as shown in Figure 4, thereby preventing the misfire phenomenon due to a decrease in the combustion tube temperature. can do.

It should be noted that the present invention is not limited to the above-described embodiment; the thyristor 8 and the transistor 13 are replaced with one transistor, and a circuit that can extract an output having hysteresis in relation to the detection output of the thermistor 5 is combined. Therefore, even if the I transistor is controlled on/off based on its output, the same effect as the above embodiment can be obtained.

As explained above, according to the combustion device according to the present invention,
Since the operation of the combustor is stopped when the temperature of the combustion tube falls below a preset combustion stop temperature, it is possible to prevent the misfire phenomenon that occurs in the conventional method.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram of a conventionally used combustion device, and FIG. 2 is a circuit configuration diagram showing an embodiment of the combustion device of the present invention.
3 is an explanatory diagram of the operation of FIG. 1, and FIG. 4 is an explanatory diagram of the operation of FIG. 2. 1... AC power supply, 2... Combustor, 3.
...DC power supply, 4゜11...Resistance, 6.
...Relay, 6a...Contact, 7...
...Transistor, 8...Thyristor, 9...
... Hot water temperature adjustment circuit, 10 ... Preheating temperature control circuit, 12 ... Switch circuit, 13 ...
・Transistor, 14.15... Resistor.

Claims (1)

[Scope of utility model registration request] A combustor including a heater that heats and vaporizes fuel, a relay that controls on/off the combustor, a transistor connected in series to the relay, and a hot water temperature adjustment circuit that controls the transistor on/off. a thermistor that detects the preheating temperature of the combustor; and a preheating temperature adjustment circuit that adjusts the preheating temperature of the combustor in relation to the detection output of the thermistor, and the combustor In the combustion apparatus, a switch circuit that operates at a temperature lower than the preheating temperature (hereinafter referred to as combustion stop temperature) is connected in series with the transistor in relation to the detection output of the thermistor. A combustion apparatus characterized in that the operation of the combustor is stopped by activating the switch circuit when the combustion cylinder temperature falls below the combustion stop temperature.