JP2663389B2 - Hot air heater - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hot air heater capable of switching a combustion state of a burner to a plurality of stages.

[Prior Art] In Japanese Patent Publication No. 63-63830, when the amount of combustion supplied to a burner is switched from strong to weak, the amount of air supplied from a convection fan is delayed by a predetermined time and then switched from strong air to weak air. An FF oil hot air heater is provided.

[Problems to be Solved by the Invention] However, in the above-mentioned FF type oil warm air heater, after the burner has been in a strong combustion state for a long time, the amount of air blown by the convection fan is switched from a strong airflow to a weak airflow. The internal temperature of the FF type oil hot air heater is significantly different from the case where the convection fan is switched from the strong air flow to the weak air flow after the burner's strong combustion state is instantaneously performed. Even in such a case where the temperature inside the machine is remarkably different, the above-mentioned FF type oil hot air heater always switches the air flow of the convection fan from the strong air flow to the weak air flow after a predetermined time has elapsed.

For this reason, when the predetermined time is set longer, assuming a case where the strong combustion state of the burner is continued for a long time, when the strong combustion state of the burner is instantaneously performed, the inside of the machine is excessively cooled, and Could blow out. Therefore, there was a problem that the heating feeling deteriorated.

In addition, when the predetermined time is set to be short, assuming that the strong combustion state of the burner is instantaneously performed, and when the strong combustion state of the burner is continued for a long time, the internal temperature decreases to a predetermined temperature or less. If not, the convection fan will have a low airflow. For this reason, there is a possibility that electric devices such as a control circuit and an overheat safety device disposed inside the FF type oil hot air heater are exposed to high temperatures. Therefore, there has been a problem that an electric device such as a control circuit or an overheat safety device malfunctions.

An object of the present invention is to provide a hot-air heater that improves a heating feeling and prevents malfunctions of electric devices provided in the device.

[Means for Solving the Problems] The invention according to claim 1 is a hot air duct for sending air into a room, and a convection blower for generating an airflow in the hot air duct toward the room. And a burner that burns fuel to heat air passing through the hot air duct, and the amount of air blown by the convection blower when the combustion state of the burner is switched from a strong combustion state to a weak combustion state. And a control circuit for switching from a strong air flow to a weak air flow by delaying a predetermined time by a predetermined time, wherein the control circuit has an internal temperature detecting means for detecting an internal temperature of the hot air heater. The technical means for setting the predetermined time longer as the in-air temperature of the hot air heater detected by the in-air temperature detecting means is higher is adopted.

[Operation] According to the invention as set forth in claim 1, when the combustion state of the burner is switched from the strong combustion state to the weak combustion state, the inside temperature of the hot air heater detected by the inside temperature detection means is high. The air flow rate of the convection air blower is switched from the strong air flow to the weak air flow with a delay of a predetermined time set to a relatively long time.

[Effects of the Invention] The invention described in claim 1 is that the predetermined time during which the convection blower continues the strong air flow changes to an appropriate length in accordance with the internal temperature of the hot air heater, thereby increasing the strength of the burner. If the combustion state of the burner is switched from the strong combustion state to the weak combustion state after the combustion state is instantaneously performed, the convection air blower will not be maintained at the strong air flow for a long time, Cold air does not blow out from the hot air duct because the inside of the hot air heater is too cold. Therefore, since the deterioration of the heating feeling in the hot air heater can be suppressed, the heating feeling can be improved as compared with the conventional hot air heater.

If the combustion state of the burner is switched from the strong combustion state to the weak combustion state after the strong combustion state of the burner has been continued for a long time, the convection air blower will be operated while the internal temperature of the hot air heater remains high. Since the blown air amount is not switched from the strong air amount to the weak air amount, electric devices such as a control circuit and an overheat safety device disposed inside the hot air heater are not exposed to a high temperature for a long time. Therefore, it is possible to prevent a malfunction of the electric device disposed inside the hot air heater.

[Embodiment] A hot air heater of the present invention will be described based on an embodiment shown in Figs. 1 to 5.

1 to 4 show a first embodiment of the present invention. FIG. 1 shows a schematic structure of an FF type gas hot air heater.

The FF gas hot air heater 1 corresponds to the hot air heater of the present invention, and includes a hot air duct 2, a convection fan 3, a combustion duct 4, a combustion fan 5, a gas burner 6, a heat exchanger 61. ,
A combustion case 62 and the microcomputer 10 are provided.

The hot air duct 2 draws indoor air from the inlet 21,
A warm air passage for blowing warm air from the outlet 22 toward the room is formed. The thermistor 11 is attached to the suction port 21. The convection blower 3, gas burner 6, heat exchanger 61 and combustion case
62 are arranged.

The convection blower 3 has an electric motor 31 whose rotation speed changes in accordance with the amount of electric current, and a convection fan 32 driven to rotate by the electric motor 31 to generate an airflow in the warm air duct 2 toward the room.

The combustion duct 4 forms an air passage for supplying the outdoor air sucked from outside and the fuel gas introduced from the fuel gas supply means 7 to the gas burner 6.

The combustion blower 5 has an electric motor 51 whose rotation speed changes in accordance with the amount of electric current, and a combustion fan 52 which is driven to rotate by the electric motor 51 and generates an airflow toward the outside in the combustion duct 4 and the gas burner 6. Having.

The gas burner 6 is a part corresponding to the burner of the present invention,
It has a combustion plate 64.

The heat exchanger 61 has one end connected to the combustion case 62 and exchanges heat between the air passing through the hot air duct 2 and the internal combustion heat. The other end of the heat exchanger 61 is connected to an exhaust duct 63. The combustion case 62 is located downstream of the combustion plate 64,
A thermocouple 12 and a spark electrode 13 are provided. The exhaust duct 63 forms an air passage for discharging the combustion exhaust gas of the air-fuel mixture to the outside of the room.

The fuel gas supply means 7 has a first main solenoid valve 71, a second main solenoid valve 72, a flow control orifice 73, a proportional control valve 74, and a gas pipe 75 in which these are disposed.

The first main solenoid valve 71 and the second main solenoid valve 72 are opened when energized, and closed when energization is stopped. Orifice 73
Is arranged in parallel with the proportional control valve 74 to adjust the supply amount of fuel gas (hereinafter referred to as gas amount). The proportional control valve 74 is
This is a valve that adjusts the amount of fuel gas by changing the degree of opening of the gas pipe 75 in accordance with the amount of energization, thereby changing the supply pressure of the fuel gas.

The microcomputer 10 is a component corresponding to the control circuit of the present invention. The microcomputer 10 receives signals from the thermistor 11, the thermocouple 12, the spark electrode 13, the operation switch 14, the temperature control button 15, and the temperature sensor 17, and displays a set temperature indicator. Control 16 The thermistor 11 is installed near the inlet 21 of the hot air duct 2 of the FF type gas hot air heater 1, and detects the temperature of the room air drawn from the inlet 21 (hereinafter referred to as room temperature). The temperature adjustment button 15 is a setting device for setting a set temperature. The set temperature display 16 displays the set temperature set by the temperature adjustment button 15. The temperature sensor 17 is a component corresponding to the internal temperature detection means of the present invention, and detects the internal temperature of the FF gas hot air heater 1, for example, the temperature in the hot air duct 2.

The microcomputer 10 includes these thermistors 11,
Thermocouple 12, operation switch 14, temperature control button 15
Electrode 13, the electric motors 31, 51, and the first main solenoid valve
71, second main solenoid valve 72, proportional control valve 74 and set temperature display
Control 16

Note that the microcomputer 10 changes the combustion state (burning amount) of the gas burner 6 between a weak burning state (weak burning amount) and a strong burning state (strong burning amount) according to the room temperature and the set temperature during the steady-state combustion control. Change. That is, the microcomputer 10 changes the energization amount of the electric motor 51 and the proportional control valve 74 according to the room temperature and the set temperature.

When the microcomputer 10 switches the combustion state of the gas burner 6 from the weak combustion state to the strong combustion state,
The amount of air blown by the convection fan 32 (the amount of electricity supplied to the electric motor 31) is changed in the same manner as the gas amount (the amount of electricity supplied to the proportional control valve 74).

Further, when switching the combustion state of the gas burner 6 from the strong combustion state to the weak combustion state, the microcomputer 10 delays the air flow of the convection fan 32 by a predetermined time after the gas amount is switched from the strong to the weak combustion state. (See graph in FIG. 2).

The microcomputer 10 sets the above-mentioned predetermined time longer as the internal temperature of the FF gas hot air heater 1 (the temperature of the hot air duct 2) detected by the temperature sensor 17 is higher. Specifically, when the temperature in the hot air duct 2 detected by the temperature sensor 17 is equal to or lower than a predetermined temperature, the above-described predetermined time is set to a first predetermined time (for example, 20 seconds). Further, when the temperature inside the hot air duct 2 detected by the temperature sensor 17 exceeds the predetermined temperature, the microcomputer 10 sets the above-mentioned predetermined time to a second predetermined time longer than the first predetermined time (for example, 40 seconds).

Here, in the graph of FIG. 2, the solid line indicates a change in the amount of gas to the gas burner 6 with the passage of time, and the broken line indicates a change in the air flow of the convection fan 32 with the passage of time.

FIG. 3 is a flowchart showing the main control of the microcomputer 10.

First, the room temperature is detected (step S1), and the set temperature is read (step S2). Then, it is determined whether or not the room temperature is higher than the set temperature (step S3). When room temperature> set temperature (Yes), the weak combustion control subroutine shown in FIG. 4 is performed (step S4), and the control of step S1 is performed.

In step S3, it is not room temperature> set temperature (No)
At this time, it is determined whether the room temperature is lower than the set temperature (step S5). When room temperature <set temperature (Yes), a strong combustion control subroutine is performed (step S6), and step S1 is performed.
Control.

In step S5, the room temperature is not smaller than the set temperature (No)
At this time, the control of step S1 is performed.

FIG. 4 shows a subroutine representing weak combustion control of the microcomputer 10.

In step S3, room temperature> set temperature (Yes)
At this time, it is determined whether the combustion state of the gas burner 6 is a weak combustion state. That is, the electric motor 51 or the proportional control valve 74
It is determined whether or not the minimum energization amount is supplied (step S11). When the combustion state of the gas burner 6 is a weak combustion state (Yes), it is determined whether or not the air flow rate of the convection fan 32 is a weak air flow rate. That is, it is determined whether the minimum energization amount is supplied to the electric motor 31 (step S12). When the minimum energization amount is supplied to the electric motor 31 (Yes), the subroutine ends.

In step S12, when the minimum energization amount is not supplied to the electric motor 31 (No), the control in step S15 is performed.

In step S11, when the combustion state of the gas burner 6 is not the weak combustion state (No), the amount of electricity supplied to the electric motor 51 is reduced to the minimum amount of electricity (step S13), and the amount of electricity supplied to the proportional control valve 74 is reduced. It is reduced to the minimum energization amount (step S14). Subsequently, it is determined whether or not the temperature in the hot air duct 2 has dropped below a predetermined value (step S1).
Five). When the temperature in the hot air duct 2 ≦ the predetermined value (Yes),
The predetermined time is set to a first predetermined time (for example, 20 seconds) (step S16), and then the control of step S18 is performed.

In step S15, the temperature in the hot air duct 2 is not equal to or less than the predetermined value, but the temperature of the hot air duct 2 is larger than a predetermined value (No).
At this time, the predetermined time is set to a second predetermined time (for example, 40 seconds) longer than the first predetermined time (step S17), and it is determined whether the predetermined time (the first predetermined time or the second predetermined time) has elapsed. (Step S18). When the predetermined time has not elapsed (No), the control in step S18 is performed.

In step S18, a predetermined time has elapsed (Yes)
At this time, the amount of current supplied to the electric motor 31 is reduced to the minimum amount of current (step S19), and then the subroutine ends.

The operation of the FF gas hot air heater 1 of the present embodiment will be described with reference to FIGS.

When the operation switch 14 is set to the “on” side, the FF-type gas warm air heater 1 is forcibly and strongly operated until a predetermined time has elapsed. After the forced “strong” operation, the combustion state of the gas burner 6 is controlled according to the temperature difference between the room temperature detected by the thermistor 11 by the microcomputer 10 and the set temperature set by the temperature adjustment button 15.

For example, when switching the combustion state of the gas burner 6 from the strong combustion state to the weak combustion state, the amount of electricity supplied to the electric motor 51 and the proportional control valve 74 of the combustion blower 5 is reduced from the maximum amount of electricity to the minimum amount of electricity. . Therefore, the rotation speed of the combustion fan 52 becomes low,
52 air volume is switched from strong air volume to weak air volume. For this reason,
The amount of outdoor air (combustion air) supplied to the gas burner 6 decreases.

Further, the amount of fuel gas supplied to the gas burner 6 is reduced by reducing the degree of opening of the gas pipe 75 by the proportional control valve 74. (See graph in FIG. 2). For this reason, even when the combustion state of the gas burner 6 is switched from the strong combustion state to the weak combustion state, an air-fuel mixture having an optimal air-fuel ratio is supplied to the gas burner 6.

The microcomputer 10 detects the temperature in the hot air duct 2 by the temperature sensor 17 and determines that the temperature has fallen below a predetermined value and the temperature inside the FF gas hot air heater 1 is low. In this case, the predetermined time until the air flow of the convection fan 32 is switched from the strong air flow to the weak air flow is set to a first predetermined time (for example, 20 seconds). If it is determined that the temperature in the hot air duct 2 exceeds a predetermined value and the internal temperature of the FF type gas hot air heater 1 is high, the predetermined time is set to a second predetermined time longer than the first predetermined time. Set the time (for example, 40 seconds).

Then, in the convection blower 3, the electric motor 31 is energized with the maximum energization amount until a predetermined time elapses. For this reason, the room air drawn into the hot air duct 2 from the suction port 21 by the rotation of the convection fan 32 is heated when passing around the heat exchanger 61 and becomes hot air at a predetermined temperature. In addition, when the room air passes through the hot air duct 2, the inside temperature of the FF gas hot air heater 1 that has been operated in the strong combustion state decreases. When the predetermined time has elapsed, the convection blower 3
The amount of current supplied to the electric motor 31 is reduced to the minimum amount of current (see the graph of FIG. 2).

As described above, since the predetermined time during which the convection fan 32 continues the strong air flow is too long, the inside of the FF gas hot air heater 1 is excessively cooled, and the cool air flows from the outlet 22 of the hot air duct 2 toward the room. Will not blow out. For this reason, the heating feeling in the FF gas hot air heater 1 can be improved.

In addition, it is possible to prevent the electric device from being exposed to a high temperature due to the short period of time during which the convection fan 32 continues the strong air flow. Therefore, malfunction of the microcomputer 10, the thermistor 11, and the temperature sensor 17 can be prevented.

FIG. 5 shows a second embodiment of the present invention, which shows a change in gas amount and a change in air flow of a convection fan over time.

In the present embodiment, the FF gas hot air heater 1 having a plurality of stages in the combustion state of the gas burner 6 is used.

(Modification) In this embodiment, the hot air duct 2 is used as the in-machine temperature detecting means.
Although the temperature sensor 17 for detecting the internal temperature is used, an internal temperature detecting means for detecting the surface temperature of the heat exchanger 61 which is the internal temperature of the hot air heater may be used.

In the present embodiment, the predetermined time is switched to two stages of a first predetermined time and a second predetermined time, but the predetermined time may be switched to a predetermined time of three or more stages.

In this embodiment, the fuel gas is used as the fuel, but a liquid fuel may be used as the fuel.

In the present embodiment, the present invention is used for the FF gas hot air heater 1, but the present invention may be used for other hot air heaters such as a fan heater.

[Brief description of the drawings]

1 to 4 show a first embodiment of the present invention. First
The figure shows the schematic structure of the FF gas hot air heater,
FIG. 3 is a graph showing a change in gas amount and a change in a blown amount of a convection fan with time, FIG. 3 is a flowchart showing main control of the microcomputer, and FIG. 4 is a subroutine showing weak combustion control of the microcomputer. . FIG. 5 shows a second embodiment of the present invention. FIG. 5 is a graph showing a change in the gas amount and a change in the blowing amount of the convection fan over time. In the figure: 1 ... FF gas hot air heater, 2 ... Hot air duct,
3 convection blower, 4 combustion duct, 5 combustion blower, 6 gas burner (burner), 10 microcomputer (control circuit), 17 temperature sensor (in-machine temperature detection means) , 32 ... convection fan, 61 ... heat exchanger,
74 …… Proportional control valve

Claims (1)

(57) [Claims] 1. A hot air duct for sending air into a room, a convection fan for generating an airflow in the hot air duct toward the room, and a fuel burner for burning the fuel into the room. A burner for heating the air passing through the burner; and when the combustion state of the burner is switched from the strong combustion state to the weak combustion state, the ventilation amount of the convection blower is delayed by a predetermined time to switch from the strong ventilation amount to the weak ventilation amount. And a control circuit, wherein the control circuit has an internal temperature detecting means for detecting an internal temperature of the hot air heater, and the hot air heating detected by the internal temperature detecting means. The hot air heater is characterized in that the predetermined time is set longer as the in-machine temperature is higher.