JPH03225158A - Hot air heater - Google Patents

Abstract

PURPOSE:To improve a heating feeling and prevent any erroneous operation of an electrical equipment in a hot air heating device by a method wherein blown air vol. of an air blower is delayed for a specified period of time in response to an indoor air temperature, a temperature in a hot air dust, a combustion state of a burner and a combustion continuing time and then a control circuit for changing-over large air vol. to small air vol. is provided. CONSTITUTION:When combustion of a burner 6 is switched from high to low, blown air vol. of a convection air blower 3 is changed over from large to small with a delay of a predetermined period of time by a control circuit 10 in response to an indoor air temperature detected by sensor means 11, 17, 12, a temperature in a hot air duct, a combustion state of a burner or a detected amount such as a combustion continuing time of a burner. In this way, the inside part of the equipment of the hot air heater 1 is not over-cooled in response to a variation of a predetermined time in which the convection air blower 3 continues to keep large air vol. and further the control circuit 10 arranged in the device or the electrical equipment such as an overheating safety device or the like is not exposed to a high temperature for a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a hot air heater in which the combustion state of a burner can be switched to a plurality of stages.

[Prior Art] Japanese Patent Publication No. 63-63830 discloses that when switching the amount of fuel supplied to a burner from strong to weak, the air flow rate of a convection fan is delayed for a predetermined time and then switched from a strong air flow rate to a weak air flow rate. An FF oil hot air heater has been proposed.

[Problems to be Solved by the Invention] However, in the above-mentioned FF type oil hot air heater, there are cases where the strong combustion state of the burner continues for a long time and then the strong combustion state is switched from strong to weak, and the strong combustion state of the burner changes instantaneously. The temperature inside the machine will be significantly different when switching from high to low after the high power is applied. Even when the temperature inside the machine is significantly different, the above-mentioned FF type oil hot air heater always switches the airflow rate of the convection fan from a strong airflow rate to a weak airflow rate after a certain predetermined period of time has elapsed.

Therefore, when a predetermined time is set assuming that the burner's strong combustion state continues for a long time, if the burner's strong combustion state occurs instantaneously, the inside of the machine will be too cool and cold air will blow from the outlet. There was a possibility that it would be released. Therefore, there was a problem that the heating feeling deteriorated.

In addition, when setting a predetermined time assuming that the burner's strong combustion state occurs instantaneously, if the burner's strong combustion state continues for a long time, the internal temperature of the machine will not fall below the predetermined temperature. However, the convection fan would have a weak air flow, which could expose electrical equipment such as control circuits and overheating safety devices inside the aircraft to high temperatures.

Therefore, there has been a problem that electrical equipment such as control circuits and overheating safety devices may malfunction.

An object of the present invention is to provide a hot air heater that improves the heating feeling and prevents malfunctions of electrical equipment installed inside the machine.

[Means for Solving the Problems] The hot air heater of the present invention includes a hot air duct for sending air toward a room, and a convection blower for generating an air flow toward the room in the hot air duct. and a burner that burns fuel to heat the air passing through the warm air duct; and when the combustion state of the burner switches from a strong combustion state to a weak combustion state, an air flow rate of the convection blower. and a control circuit that switches from a strong air volume to a weak air volume with a delay of a predetermined time, the control circuit controlling the temperature in the room, the temperature in the hot air duct, the combustion state of the burner, or the combustion duration time of the burner. The present invention employs a technical means that includes a detection means for detecting one or more of the following, and changes the predetermined time according to the amount detected by the detection means.

[Function] The air flow rate of the convection blower is determined by the indoor temperature detected by the detection means, the temperature inside the hot air duct, and the combustion of the burner when the combustion state of the burner switches from the strong combustion state to the weak combustion state. The strong airflow rate is switched to the weak airflow rate after a predetermined time delay depending on the state or a detected amount such as burner combustion duration.

In this way, by changing the predetermined time during which the convection blower continues to produce strong airflow to an appropriate length according to the detected amount,
To avoid over-cooling the inside of a hot-air heater, and also to avoid exposing electrical equipment such as a control circuit and an overheating safety device installed inside the machine to high temperatures for a long time.

[Effects of the Invention] The heating feeling in the warm air heater can be improved, and malfunctions of electrical equipment such as a control circuit and an overheating safety device installed in the warm air heater can be prevented.

[Example] The hot air heater of the present invention will be explained based on the example shown in FIGS. 1 to 5.

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

The FFFF gas hot air heater 1 includes a hot air duct 2, a convection blower 3, a combustion duct 4, a combustion blower 5, a gas burner 6, a heat exchanger 61, a combustion case 62, and a microcomputer 10.

The hot air duct 2 sucks indoor air from the intake port 21,
This is a hot air passageway that blows hot air toward the room from the air outlet 22. Further, a thermistor 11 is attached to the suction port 21. Inside the hot air duct 2, a convection blower 3, a gas burner 6, a heat exchanger 61, and a combustion case 62 are arranged.

The convection blower 3 includes an electric motor 31 whose rotational speed changes depending on the amount of electricity supplied, and a convection fan 32 that is rotationally driven by the electric motor 31 and generates an air flow toward the room in the hot air duct 2.

The combustion duct 4 is an air passageway that supplies the gas burner 6 with outdoor air taken in from outside and fuel gas introduced from the fuel gas supply means 7 .

The combustion blower 5 includes an electric motor 51 whose rotational speed changes depending on the amount of electricity supplied, and is rotationally driven by the electric motor 51. It has a fan 52.

The gas burner 6 is the burner of the present invention and 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 internal combustion heat. The other end of this heat exchanger 61 is connected to an exhaust duct 63. The combustion case 62 includes a thermocouple 12 and a spark electrode 13 on the downstream side of the combustion plate 64.
has been set up. The exhaust duct 63 is an air passageway that discharges combustion exhaust gas of the air-fuel mixture to the outside.

The fuel gas supply means 7 includes a first main solenoid valve 71, a second main solenoid valve 12, a flow rate adjustment orifice 73, a proportional control valve 74,
and a gas pipe 75 in which these are arranged.

The first main electromagnetic valve 71 and the second main electromagnetic valve 72 open when energized, and close when energization is stopped.

The orifice 73 is arranged in parallel with the proportional control valve 74 and adjusts the amount of fuel gas supplied (hereinafter referred to as gas amount).

The proportional control valve 74 is a valve that changes the supply pressure of the fuel gas by changing the degree of opening of the gas pipe 75 in accordance with the amount of energization, thereby adjusting the amount of the fuel gas.

The microcomputer 10 is a control circuit of the present invention, and inputs signals from the thermistor 11, thermocouple 12, spark electrode 13, operation switch 14, temperature adjustment button 15, and temperature sensor 17, and controls the set temperature display 16.
control. The temperature adjustment button 15 is a setting device for setting a set temperature. The set temperature display 16 is connected to the temperature adjustment button 1
The set temperature set in step 5 is displayed. The temperature sensor 17 is a detection means of the present invention, and is for detecting the temperature inside the hot air duct.

The microcomputer 10 uses these thermistors 11
, the spark electrode 13 and the electric motor 31.51 in response to electrical signals sent from the thermocouple 12, the operation switch 14, the temperature adjustment button 15, and the temperature sensor 17.
, first main solenoid valve 71, second main solenoid valve 72, proportional control valve 7
4 and the set temperature display 16.

Note that during the steady combustion control, the microcomputer 10 changes the combustion state of the gas burner 6 between weak combustion control and strong combustion control in accordance with the room temperature and the set temperature. That is,
The microcomputer 10 changes the amount of electricity supplied to the electric motor 51 and the proportional control valve 74 in accordance with 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 microcomputer 10
The amount of air blown by the convection fan 32 (the amount of current applied to the electric motor 31) is changed in the same way as the amount of gas (the amount of current applied to the proportional control valve 74).

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

The microcomputer 10 then uses a temperature sensor 17.
When the temperature inside the hot air duct detected by is below a predetermined temperature, the predetermined time is set to a first predetermined time (for example, 20 seconds). Furthermore, when the temperature inside the hot air duct detected by the temperature sensor 17 exceeds a predetermined temperature, the microcomputer 10 sets the predetermined time to a second predetermined time (for example, 40 seconds).

Here, in the graph of FIG. 2, the solid line indicates the gas burner 6.
The broken line shows the rate of change in the amount of air blown by the convection fan 32.

FIG. 3 shows a flowchart representing 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 the room temperature has risen above the set temperature (step S3), and when the room temperature is higher than the set temperature (Yes), the weak combustion control subroutine shown in FIG. 4 is performed (step S4), and step Controls S1.

In step S3, the room temperature is not the set temperature (NO)
, determine whether the room temperature is lower than the set temperature (
Step S5), when the room temperature is lower than the set temperature (Yes1), a strong combustion control subroutine is performed (step S6), and the control of step S1 is performed.

In step S5, the room temperature is not the set temperature (NO)
At this time, the control in 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. In other words, it is determined whether the minimum amount of current is being supplied to the electric motor 51 or the proportional control valve 74 (
In step 511), when the combustion state of the gas burner 6 is a weak combustion state (<Yes), it is determined whether the air flow rate of the convection fan 32 is a weak air flow rate.

That is, it is determined whether the minimum amount of current is supplied to the electric motor 31 (step S12>, the electric motor 31
The minimum energization amount is supplied to (Yes 1, the subroutine ends.

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

In step Sll, when the combustion state of the gas burner 6 is not a weak combustion state (No), the amount of electricity supplied to the electric motor 51 is reduced to the minimum amount of electricity (step 513),
The amount of current supplied to the proportional control valve 74 is reduced to the minimum amount of current (step 514). Next, it is determined whether the temperature inside the hot air duct has fallen below a predetermined value (step 515). Temperature in the hot air duct ≦ predetermined value (
If Yes), the predetermined time is set to the first predetermined time (step 31B), and then the control of step 818 is performed.

In step S15, the temperature inside the hot air duct is not ≦the predetermined value, but the temperature inside the hot air duct>the predetermined value (NO).
step 517 to set the predetermined time as the second predetermined time.
), it is determined whether a predetermined time has elapsed (step 318); if the predetermined time has not elapsed (NO), the control in step 318 is performed.

In step S18, the predetermined time has elapsed (Yes
), the amount of current supplied to the electric motor 31 is reduced to the minimum amount of current (step 519), and then the subroutine is ended.

The FF type gas hot air heater 1 of this embodiment is shown in Figures 1 and 2.
This will be explained based on the diagram.

When the operation switch 14 is set to the "on" side, the FF gas hot air heater 1 is forced to operate on "strong" until a predetermined time elapses. After the forced "strong" operation, the microcomputer 10
The combustion state of the gas burner 6 is controlled according to the temperature difference between the room temperature detected by the thermistor 11 and the set temperature set by the temperature adjustment button 15.

For example, when switching the combustion state of the gas burner 6 from a strong combustion state to a weak combustion state, the amount of current supplied to the electric motor 51 and the proportional control valve 74 of the combustion blower 5 is reduced to the minimum amount of current.

Therefore, as the rotational speed of the combustion fan 52 becomes low, the amount of air blown by the combustion fan 52 is switched from a strong air amount to a weak air amount. Therefore, the amount of outdoor air (combustion air) supplied to the gas burner 6 decreases.

Further, as the opening degree of the gas pipe 75 is reduced by the proportional control valve 74, the amount of fuel gas supplied to the gas burner 6 is also reduced (see the graph in FIG. 2). Therefore, even when the combustion state of the gas burner 6 is switched from the strong combustion state to the weak combustion state, the air-fuel mixture with the optimum air-fuel ratio is supplied to the gas burner 6.

Note that the microcomputer 10 detects the temperature inside the hot air duct with the temperature sensor 17, and when the temperature is below a predetermined value, sets a predetermined time period until the convection fan 32 switches to a weak air volume as a first predetermined time period. .

In addition, if the temperature inside the hot air duct exceeds a predetermined value and it is determined that the temperature inside the FF gas hot air heater 1 is high, the predetermined time is changed to a second predetermined time that is longer than the first predetermined time. Set.

Then, in the convection blower 3, the electric motor 31 is energized at the maximum amount of energization until a predetermined period of time has elapsed.

Therefore, the indoor air sucked into the hot air duct 2 from the suction port 21 by the rotation of the convection fan 32 is transferred to the heat exchanger 6.
1, it is heated and becomes warm air at a predetermined temperature. In addition, when the indoor air passes through the hot air duct 2, the FF type gas hot air heater 1, which was operated in a strong combustion state,
After a predetermined period of time has elapsed, the amount of current supplied to the electric motor 31 of the convection blower 3 is reduced to the minimum amount of current (see the graph in FIG. 2).

As described above, if the predetermined time period during which the convection fan 32 continues to generate a strong air volume is too long, the interior of the machine is cooled too much and cold air is no longer blown out from the outlet 22 of the hot air duct 2. Therefore, the heating feeling in the FF type gas hot air heater 1 can be improved. Furthermore, it is possible to prevent the electrical equipment from being exposed to high temperatures due to the predetermined time during which the convection fan 32 continues to generate strong airflow being too short. Therefore, malfunction of the microcomputer 10, thermistor 11, and temperature sensor 17 can be prevented.

FIG. 5 shows the relationship between the rate of change in the amount of gas and the rate of change in the amount of air blown by the convection fan and time, adopted in the second embodiment of the present invention. An FF type gas hot air heater 1 having stages is used.

(Modification) In this example, the temperature inside the hot air duct was detected, but the detection means include the surface temperature of the heat exchanger, the amount of fuel per unit time, the amount of combustion air per unit time, and the combustion state of the burner. Alternatively, other detection means for detecting any one of the burner combustion duration or a combination thereof may be used.

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

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

In this embodiment, the hot air heater is used as an FF type gas hot air heater, but the hot air heater may be used for other hot air heaters such as a fan heater.

[Brief explanation of drawings]

1 to 4 show a first embodiment of the present invention.
The figure is a configuration diagram showing the schematic structure of an FF type gas hot air heater, Figure 2 is a graph showing the relationship between the rate of change in gas amount and the rate of change in air flow rate of the convection fan and time, and Figure 3 is a microcomputer. FIG. 4 is a flowchart showing the main control of the microcomputer, and FIG. 4 is a subroutine showing the weak combustion control of the microcomputer. FIG. 5 shows a second embodiment of the present invention. FIG. 5 is a graph showing the relationship between the rate of change in the amount of gas and the rate of change in the amount of air blown by the convection fan versus time. In the diagram 1...FF type gas hot air heater 2...Hot air duct 3
... Convection blower 6 ... Gas burner (burner) 1
0...Microcomputer (control circuit) 17...
Temperature sensor (detection means)

Claims (1)

[Scope of Claims] 1) A hot air duct for sending air toward a room; a convection blower for generating an air flow toward the room in the hot air duct; a burner that heats the air passing through the wind duct; and when the combustion state of the burner switches from a strong combustion state to a weak combustion state, the air flow rate of the convection blower is delayed by a predetermined period of time to reduce the air flow rate from the strong air volume to the weak combustion state. a control circuit that switches to an air flow rate, and the control circuit detects one or more of the temperature in the room, the temperature in the hot air duct, the combustion state of the burner, or the duration of combustion of the burner. 1. A warm-air heater, comprising: a detection means for detecting a temperature, and changing the predetermined time according to a detection amount detected by the detection means.