JPS602821A - liquid fuel combustion equipment - Google Patents

Abstract

PURPOSE:To prevent abnormal increase of temperature, by a method wherein, when an evaporating combustion part is extraodinarily increased in temperature, combustion is stopped and energization to an evaporating heater is disconnected, and only a burner motor is operated to feed blast to the evaporating combustion part. CONSTITUTION:In case a contact 15a is brought into a welding state, energization to an evaporating heater 3 is continued, and when the temperature of an evaporating combustion part is increased to an excess rise detecting level determined by resistors 9, 10 and 11, the output of a comparator 13 is inverted to be brought to ''1''. This causes OR circuits 21 and 22 to be inverted a ''1'' output, and brings a combustion control circuit 26 into a stop state, forces driving parts 27 and 29 into an OFF-state, and brings a relays 30 and 31 into a non-exciting state, resulting in stop of combustion. Simultaneously, a transistor 25 is brought into an ON-state, the input of a driving part 16 is brought to ''0'', and a relay 15 is brought into a non-exciting state. Further, a signal is fed to a driving part 28, the relay 30 and a contact 30a are brought into an exciting state and a closing state, respectively, and a burner motor 4 is driven. This causes the air to be fed to the evaporating combustion part to cool it, and permits prevention of abnormal increase in temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a vaporization type liquid fuel combustion apparatus equipped with a vaporization heater.

Conventional configuration and its problems Conventionally, in this type of burner temperature detection circuit, if the temperature of the evaporative combustion section rises abnormally for some reason, the over-rise temperature detection circuit detects whether the temperature has reached the set temperature. When this happens, it is determined that there is an abnormality, and a signal is sent to the safety circuit to stop combustion and stop energizing the evaporation heater.
It was. Therefore, in cases such as when the contacts of the relay for controlling the vaporization heater are mechanically welded, the relay contact will close even if the overheating detection circuit is activated and the power supply to the vaporization heater is stopped. The state remains X, and the energization to the vaporization heater continues. The evaporative heater goes out of control, the temperature rises abnormally, and the evaporative combustion section becomes molten. If the current continues, the insulation of the evaporative heater may deteriorate, resulting in a very dangerous situation such as electrical leakage.

Purpose of the Invention The present invention has been made in view of the above-mentioned point of contact, and is intended to reduce the abnormal temperature rise in the vaporization combustion section due to runaway of the vaporization heater when welding the contacts of the vaporization heater control relay, and to reduce the melting of the vaporization combustion section. The purpose is also to prevent insulation deterioration of the vaporization heater.

Structure of the Invention In order to achieve the above object, the present invention is to stop combustion and stop power supply to the vaporization heater when the temperature of the vaporization combustion section rises abnormally, and at the same time operate only the burner motor to blow air to the vaporization combustion section. The structure is such that the vaporization and combustion section is cooled by the following. As a result, even if the contacts of the evaporative heater control relay are welded, the temperature will not rise to such a level that the evaporative combustion part will melt, and a balance will be maintained with a low temperature rise, resulting in safety.

Description of examples An example of this will be described below with reference to FIG.

In Figure 1, 1 is an operation switch, 2 is a power transformer for the control circuit, 3 is a vaporization heater, 4Ii is a burner motor for supplying combustion air, 5 is a combustion device, 6 is a DC power supply for I-i control circuit, 7 is vaporization combustion Thermistors 8 to 12 are resistors for temperature detection and are used for temperature control and setting of excessive temperature detection level. 13 is a comparator for detecting excessive temperature; 14 is a temperature control comparator; 15 is a vaporization heater control relay; 15a is a contact point of the relay 15; 16 is a drive unit 17-18 is a resistor;
9~2o are diodes for forming self-holding, 21゜2
2 is an OR circuit which is operated by the outputs of the comparators 13 and 14. 23 to 24 are resistors, 25 is a transistor, 26 is a combustion control circuit, 27 to 29 are drive units, 30 is a burner motor drive relay, 30a is a contact point of the relay 30, 31
31a is a relay for controlling the combustion device, 31a is a contact of the relay 31, 32 is a safety circuit, 33 is a drive unit, 34 is a latching relay, 34a is a contact of the relay 34, and 35 is a combustion detection circuit.

The operation of the above-mentioned configuration will be described. When the uninterrupted operation switch 1 is turned on, power is supplied to the control circuit by the power transformer 2 and the DC power circuit 6. If the temperature of the vaporization combustion section is low at this point, the resistance value of the thermistor 7 is large, so the comparator 13 has an output of ○, and the OR circuit 21 also has an output of 0. Also, since the comparator 14 has an output of 1, the drive unit 1
6 is turned on, the relay 16 is energized, and the contact 15a is closed. As a result, energization of the vaporization heater 3 is started. At the same time, the input of the OR circuit 22 also becomes 1 state, so the output becomes 1 and the combustion control circuit 26 is held in a stopped state. When the energization of the vaporization heater 3 progresses and the temperature of the vaporization combustion section reaches a predetermined temperature, the output of the comparator 14 is reversed and becomes 0. As a result, the relay 15 is de-energized, the contact 15a is opened, and the energization to the vaporization heater 3 is stopped. At this point, the OR circuit 22
The output becomes 0, canceling the stop signal to the combustion control circuit 26, supplying signals to the drive units 27 and 29 in a predetermined sequence, and setting the relays 30 and 31 in an excited state to start combustion. The OR circuit 22 forms a self-holding circuit using the diode 20, and thereafter holds the O state regardless of the output of the comparator 14. Also, at this point, the output of the comparator 13 is 0,
The above state is maintained and normal combustion begins.

Next, if the contact point 15a becomes welded for some reason, the energization of the vaporization heater 3 continues, and the temperature of the hess combustion part increases abnormally. When the voltage rises to the over-rise detection level, which is stabilized by resistors 9 and 10.11, the output of comparator 13 is inverted and becomes 1. As a result, the OR circuit 21 becomes output 1, and O
The input of the R circuit 22 is set to 1, the output is reversed to 1, the combustion control circuit 26 is stopped, the drive units 2 and 29 are set to F'F, and the relays 30 and 31 are de-energized to stop combustion. At the same time, the transistor 25 is turned on, the input of the drive unit 16 is set to O, and the relay 15 is de-energized.

Further, a signal is supplied to the drive unit 28 to excite the relay 3o, that is, close the contact 30a, and turn the burner motor 4 on.
drive only. As a result, air is supplied to the vaporization combustion section, so even if the vaporization heater 3 is continuously energized, it is cooled and the temperature does not rise abnormally. Further, since the OR circuit 21 is self-maintained by the diode 19, once it reaches the 1 state, it continues to maintain that state even if the temperature of the vaporization combustion section decreases and the output of the comparator 13 becomes the O state.

Furthermore, although the above-mentioned state is canceled by opening the operation switch 1, the current supply to the vaporization heater 3 is also stopped, so that the vaporization heater 3 does not run out of control.

Effects of the Invention As described above, according to the present invention, when the temperature of the evaporative combustion section rises abnormally, opening the operation switch stops power supply to the combustion and evaporation heaters, and causes the burner motor to operate slowly.
Since the vaporization combustion section is cooled, an abnormal temperature rise in the vaporization combustion section is prevented. It is particularly effective in preventing abnormal temperature rises in the vaporization combustion section when the vaporization heater goes out of control due to mechanical factors such as welding of relay contacts for controlling the vaporization heater.

[Brief explanation of the drawing]

The figure is a control circuit diagram of a liquid fuel combustion device in one embodiment of the present invention. 1... Operation switch, 3... Evaporation heater, 4... Burner motor, 5... Combustion device, 7... Temperature detection thermistor .

Claims (1)

[Claims] A vaporization heater that vaporizes the liquid fuel supplied to the vaporization and combustion section, a temperature detection thermistor that detects the temperature of the vaporization and combustion section, a fuel supply means that supplies liquid fuel to the vaporization and combustion section, and the vaporization and combustion section. a burner motor that supplies air to the
A safety device is installed so that when the temperature of the vaporization combustion section rises above a predetermined temperature, electricity to the vaporization heater and combustion are stopped, and only the burner motor continues to operate by opening the operation switch. Liquid fuel combustion equipment.