JPH0195253A - Burner - Google Patents

Abstract

PURPOSE:To prevent a burner from overheating by stopping it from burning when a detected signal that shows that the number of revolution reaches a predetermined number does not come from a detecting circuit within a predetermined time after a control circuit outputs a driving signal to a motor. CONSTITUTION:When an operation switch 2 is closed, a microcomputer 1 outputs 'H' from an output port 'P0', starting a CR timer 'C', as well as to start a motor 3 driving. From this time prepurge is taken place within a predetermined time. The output from a secondary comparator 13 remains to hold 'H' when the number of revolution of a motor 3 does not reach a predetermined number or if the motor does not rotate at all. In this case the positive input voltage of a tertiary comparator 18 in a timer circuit 'B' exceeds the voltage on the negative side of which resistance is a divided value between resistors 23 and 24, by the output 'H' from the output port 'P0' of a microcomputer 1. At that time, the output from the tertiary comparator 18 is 'H', and a transistor 19 is turned ON to make the error port 'P1' of a microcomputer 1 'L'. Accordingly the microcomputer 1 does not proceed to an igniting operation after the prepurge is completed, as a result, all the operations are stopped.

Description

[Detailed description of the invention] (a) Industrial application field This invention burns gas, kerosene, etc., and discharges the high-temperature exhaust gas and combustion heat generated by the combustion to the outside of the device as hot air. The present invention relates to combustion devices such as hot air heaters that perform heating.

(b) Conventional technology This type of conventional warm air heater is, for example,
As disclosed in Japanese Patent No. 1243, it is common to have a configuration in which combustion exhaust gas and combustion heat generated by a burner are discharged forward by a hot air fan disposed below the burner.・ However, with this structure, if, for example, foreign matter adheres to the hot air fan and it stops rotating, the upper part of the burner will become abnormally heated. was.

However, since the surface temperature of the heater rises to an abnormal temperature as well as the inside temperature, there is a risk that the user may get burnt or the resin used for the operating parts etc. may become deformed.

(8) Problems to be solved by the invention This invention has been made in view of the above-mentioned facts,
The purpose is to prevent the device from overheating if the hot air fan stops for some reason.

(d) Means for Solving Problems The combustion device of the present invention includes a burner that burns gas or kerosene, and high-temperature exhaust gas generated by the combustion of the burner or the combustion heat that is sent to the outside of the device as hot air. A combustion control circuit that controls the driving of a hot air fan that discharges hot air, a motor for driving the fan, and a combustion control circuit that detects the rotation of the motor and outputs a detection signal when the rotation speed reaches a predetermined number or more. The configuration includes a rotation detection circuit and a timer circuit that stops combustion of the burner if a detection signal is not input from the detection circuit within a predetermined time after the control circuit outputs a motor drive signal.

(*) Effect With this configuration, if the warm air fan stops for some reason or does not rotate sufficiently even though the motor drive signal is being issued, the timer circuit will stop the burner combustion. This prevents abnormal heating of the combustion section and equipment.

(f) Example Hereinafter, embodiments of the present invention shown in the drawings will be described.

FIG. 3 shows a gas hot air type heater as a combustion device to which the present invention is applied, and this heater has a gas burner a serving as a heat source and a hot air fan b inside the main body.

In addition, after indoor air sucked through the intake port d provided at the back of the exterior case C is heated by the gas burner a through the convection passage C, the indoor air and combustion gas from the gas burner a are transferred to the exhaust port provided at the lower front of the exterior case C. The air is discharged into the room from the outlet r for heating.

FIGS. 1 and 2 show a control device for the above-mentioned heating machine. In Figures 1 and 2, (1) is a motor (3) for driving a warm air fan (b), a gas valve (as a fuel supply means), and a gas valve (
4), a microcomputer as a combustion control circuit that controls the operation of the ignition device (5), etc.; (6) is a Hall element that detects the rotation speed of the motor (3); It outputs pulses. (7) is a first comparator that converts the impedance of the pulse output from the Hall element (6); (8) is a watchdog circuit that monitors the output of the first comparator (7); ) (to), and diodes (11) and (12). (13) is the watchdog circuit (
A second comparator is provided with an output of 8) supplied to one input terminal and a reference voltage supplied to 10 input terminals. This is to determine whether the number is greater than or equal to the number. Further, the reference voltage is determined by the divided voltage of resistors (14) and (15). A rotation detection circuit (A) is constituted by the above-described first and second humparators (7) and (13), the Hall element (6), and the watchdog circuit (8).

(B) is a timer circuit, and the timer circuit (B) is a resistor (16
), a CR timer (C) consisting of a capacitor (17), a third comparator (18) and a transistor (19)
It consists of

(20) is a photo try book, which controls the on/off of the motor (3) based on the output from the microcomputer (1). Also, (21) and (22) are transistors that can be supplied with the output of the microcomputer (1), (23) and (24) are relays, and (23A and 24A) are their contacts.

Next, the operation will be explained.

When the operation switch (2) is closed, the microcomputer (1) starts driving the motor (3) and also switches the output boat (Po
) outputs “H” from CR timer (C) (resistance (1
6) and capacitor (17)) are started.

(This timer is set within the bleepurge time.) From here, the breipurge is performed for a predetermined period of time, and when the rotation speed of the motor (3) reaches the predetermined number of rotations during this bleepurge time, the The output of the second comparator (13) becomes "L", and the operation of the timer (C) is stopped and reset. Therefore, the third comparator (18)
The output of is fixed to "L", and after the completion of the briverage, the microcontroller (1) conducts the transistors (21) and (22) because the error port (Pr) input is "H" and activates the relay (
23) Close the contacts (23A) (24A) of (24),
The gas pulp (4) and the igniter (5) are activated to supply gas to the burner and ignite and burn it.

Next, a case will be described in which the rotational speed of the motor (3) is less than a predetermined rotational speed or the motor (3) is stopped during blip-purging.

If the rotation speed of the motor (3) does not reach the predetermined rotation speed or does not rotate due to motor lock, etc., the output of the second fan plater (13) remains “H”, so the microcontroller (1) The “H” output of the output capo (P,) causes the third humpator (18
) exceeds the dividing resistance of resistors (23) and (24) on one side. At this time, the output of the third comparator (18) becomes "H", the transistor (19) turns on, and the error port (P, ) of the microcomputer (1) becomes "L", thus ending the re-purge. Thereafter, the microcomputer (1) determines that the motor is locked, does not proceed to ignition operation, and stops all operations.

Note that the rotation detection circuit (A) and the timer circuit (B) can also be built into the microcomputer (combustion control circuit) (1), excluding the detection section.

(G) Effects of the Invention Since this invention is configured as described above, it is possible to prevent combustion from occurring in the event that the hot air fan remains stopped, and prevent abnormalities in the combustion section from occurring as in the past. Compared to systems that detect a sudden temperature rise and stop combustion, this method eliminates problems such as burns and deformation of the resin due to overheating of the device, and is superior in safety and reliability.

[Brief explanation of the drawing]

Figures 1 to 3 relate to one embodiment of the present invention, with Figure 1 being an electric circuit diagram showing one example of a control device, Figure 2 being a block diagram as well, and Figure 3 being a combustion device. FIG. 1 is a schematic structural explanatory diagram of a gas hot air heater. (1)...Microcomputer (combustion control circuit), (3)...
・Motor, (A)... Rotation detection circuit, (B)... Timer circuit, (a)... Gas burner, (b)... Warm air fan. Figure 2 Figure 3

Claims (1)

[Claims] (1) A burner that burns gas or kerosene, etc., and a hot-air fan that discharges the high-temperature exhaust gas generated by the combustion of the burner or the combustion heat to the outside of the device as hot air;
and a motor for driving the fan, a combustion control circuit that controls the drive of the motor, a rotation detection circuit that detects the rotation of the motor and outputs a detection signal when the rotation speed reaches a predetermined number or more, and the control circuit. A combustion device comprising: a timer circuit that stops combustion of the burner if a detection signal is not input from the detection circuit within a predetermined time after the circuit outputs a drive signal for the motor.