JPH04302949A - Hot air heater - Google Patents

Abstract

PURPOSE:To prevent operation noise as a room temperature is increased from being increased, restrict an increasing of temperature within an outer case when an air filter is clogged and to enable a clogging to be positively carried out even if the temperature increasing is restricted. CONSTITUTION:A control device 19 for a hot air heater has a clogging sensor 23 for sensing a clogging of an air filter and a clogging display device 29. When the clogging sensor 23 detects a clogging, the number of rotations of a driving motor FM for a blower fan is controlled to be a little bit higher and then the clogging displaying device 29 is operated regardless of a signal from the clogging sensor 23.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention supplies indoor air to a burner, such as a gas fan heater or an oil fan heater.
This invention relates to an open-type hot air heater that releases combustion gas indoors.

0002

[Prior Art] Conventionally, for example, a gas fan heater has a burner placed inside an outer case having an air inlet and a warm air outlet, and a combustion chamber facing the burner, as disclosed in Japanese Utility Model Publication No. 63-50602. It is known to have a chamber and a blower fan that supplies air sucked in from the air suction port to the burner and discharges combustion gas from the hot air outlet, and an air filter is provided at the air suction port.

In addition, in recent years, control devices have been installed that finely adjust the amount of fuel consumed by the burner by controlling the amount of fuel supplied to the burner and the air volume of the blower fan according to room temperature, etc., to improve the combustion state of the burner. This makes it possible to precisely control the room temperature while maintaining the same temperature.

0004

[Problems to be Solved by the Invention] By the way, there are two methods for controlling the air volume of a blower fan: one is a method in which a predetermined voltage is applied to a drive motor (DC motor), and the other is a method in which a predetermined voltage is applied to a drive motor (DC motor) in order to obtain an air flow commensurate with the amount of fuel consumed. A known method is to detect the rotation speed of a fan and control the phase or voltage of a drive motor (AC or DC motor) to maintain a predetermined rotation speed.

In the former method, when the load on the drive motor is reduced due to clogging of the air filter, the load on the drive motor is reduced accordingly.
While this has the advantage of increasing the rotation speed of the drive motor and suppressing the temperature rise inside the outer case, the rotation speed of the blower fan also changes due to changes in room temperature (changes in air density).
There was a drawback that the noise value increased as the room temperature rose.

On the other hand, with the latter rotation speed control method, there is no problem that the rotation speed increases as the room temperature rises during combustion, but if the air filter becomes clogged, the air volume decreases and the temperature inside the outer case increases. There was a problem in that the high limit switch, which is used to stop combustion when overheating, was more likely to operate.

[0007] This invention was made in view of the above-mentioned fact, and is a device that controls the amount of fuel supplied to the burner and the air volume of the blower fan to adjust the amount of fuel consumed by the burner. To suppress an increase in temperature inside an outer case when an air filter is clogged, while preventing an increase in operating noise due to the rise in temperature, and to accurately display a clogging indication.

[0008]

[Means for Solving the Problems] In the present invention, a burner is provided in an exterior case having an air intake port and a hot air outlet, a combustion chamber facing the burner, and air sucked from the air intake port is supplied to the burner. At the same time, a blower fan is installed to discharge the combustion gas from the hot air outlet, and an air filter is installed at the air intake port to control the amount of fuel supplied to the burner and the rotational speed of the blower fan, thereby reducing the amount of fuel consumed by the burner. In a hot air heater equipped with a control device for adjusting the air filter, the control device has a clogging detector and a clogging indicator for detecting clogging of the air filter, and the clogging detector detects clogging. In some cases, the ratio of the fan speed to the fuel consumption is increased and the clogging indicator is activated independently of the clogging detector signal.

[0009]

[Operation] Since the system controls the number of rotations of the blower fan, there is no need to worry about the noise level increasing as the room temperature rises during combustion. In addition, if the air filter is clogged and the clogging detector detects that the air filter is clogged, the control device increases the ratio of the fan rotation speed to the fuel consumption, and the signal from the clogging detector is Since the clogging indicator is activated independently, the decrease in air volume of the blower fan is compensated for, and the temperature rise inside the outer case is not only suppressed, but also the signal of the clogging detector is increased by correcting the rotation speed of the blower fan. Even if the air filter changes, the clogging indicator can continue to operate and prompt the customer to clean the air filter.

0010

Embodiments Hereinafter, embodiments in which the present invention is applied to a gas fan heater will be described with reference to the drawings.

In FIG. 4, reference numeral 1 denotes an exterior case having an air inlet 2 with an air filter F attached to the upper back, and a hot air outlet 3 at the lower front. 5 is a gas burner provided in the combustion chamber 4; 6 is a blower fan consisting of a cross-flow fan provided below the combustion chamber 4; 7 is a cover plate that covers the top and front surface of the combustion chamber 4; 8; is interposed between the combustion chamber 4 and the cover plate 7, and guides the air flowing in from the suction port 2 and the combustion gas from the combustion chamber 4 to the blower fan 6; Fan casing leading to wind outlet 3, 10
is an automatic winding type cord reel device provided in a lower space 12 inside the outer case 1 partitioned by the fan casing 9.

The cord reel device 10 has a protective cover 13 made of resin, and a power cord 14 can be inserted or removed from the lower rear side of the exterior case 1. Further, the power cord 14 is pulled out manually, and when the power cord 14 is stored, the power cord 14 is pulled and released, so that winding is automatically performed.

Reference numerals 15 and 16 denote rectifier plates 1 which also serve as heat shield plates and are provided in the air passage 17 between the cover plate 7 and the outer case 1.
Reference numeral 8 denotes a stand which also serves as the bottom plate of the exterior case 1, 19 a control device, 20 operation circuit parts such as an operation switch 21, 22 a room temperature detector made of a thermistor, 23 a clogging detector made of a thermistor, and 24 a bimetallic type. overheating detector,
25 is an igniter.

FIG. 1 shows the basic configuration of the control device 19. In FIG. 1, 26 is a microcomputer (hereinafter referred to as microcomputer) that has a built-in A/D converter, and the input side of the microcomputer 26 has an operation switch 21, a temperature setting device S, a room temperature detector 22, and an eye. A clogging detector 23 and an overheating detector 24 are provided. Further, on the output side of the microcomputer 26, a solenoid valve 27 and a proportional control valve 28 inserted into the gas supply pipe (not shown) of the gas burner 5, an igniter 25, and a motor FM for driving the blower fan 6, A filter lamp 29 is provided as a clogging indicator.

The drive motor FM is provided with a rotation speed detector 30, and its detection signal is input to the microcomputer 26. Further, the temperature setting device S and the filter lamp 29 are arranged at the upper front of the exterior case 1 together with the operation switch 21.

When the operation switch 21 is turned on, the microcomputer 26 opens the solenoid valve 27 and the proportional control valve 28.
The igniter 25 is activated, and the driving motor FM of the blower fan 6 is started. At this time, indoor air is sucked into the exterior case 1 from the air suction port 2 by the blower fan 6, and a portion of the air enters the combustion chamber 4 through the intake port 4A. Then, this air is mixed with gas fuel supplied via the solenoid valve 27 and the proportional control valve 28, and is burned in the gas burner 5.

After the combustion gas of the gas burner 5 is discharged from the exhaust port 4B, the air in the ventilation passage 8 cools the outer wall of the combustion chamber 4, and the control device 1 in the upper and front parts of the exterior case 1.
The air is combined with the air that suppresses the temperature rise of the operating circuit components 9 and the operating circuit components 20, and is sucked into the blower fan 6. The hot air discharged from the blower fan 6 is guided to the hot air outlet 3 along the fan casing 9 and is discharged into the room.

During such a heating operation, the microcomputer 26 determines the amount of fuel consumed by the gas burner 5 in accordance with the magnitude of the temperature difference between the temperature set by the temperature setting device S and the temperature detected by the room temperature detector 22. For example, as shown in Figure 2, the fuel consumption is 60
It is adjusted in multiple stages or steplessly in the range of 0 kcal/h to 3000 kcal/h. Then, in order to obtain this amount of fuel consumption, the microcomputer 26 adjusts the opening degree of the proportional control valve 28, controls the amount of fuel supplied to the gas burner 5, and controls the rotation speed of the drive motor FM. The amount of air supplied to the gas burner 5 by the blower fan 6 is controlled.

The rotation speed of the drive motor FM is controlled by the rotation speed signal from the rotation speed detector 30 and the set rotation speed (here, FIG.
As shown in FIG. 2, the rotation speed of the blower fan 6 is compared with the set rotation speed (set in the range of 550 rpm to 1230 rpm), and the voltage control or phase control of the drive motor FM is performed so that the rotation speed of the blower fan 6 becomes the set rotation speed.

[0020] In this way, the room temperature is maintained near the set temperature by precisely controlling the amount of fuel consumed by the gas burner 5 in accordance with the magnitude of the heating load. When the room temperature rises to near the set temperature, the amount of fuel consumed by the gas burner 5 becomes the minimum, and the rotational speed of the blower fan 6 also becomes the minimum, resulting in stable operation with low noise.

[0021] When air filter F becomes clogged,
Since the rotation speed of the blower fan 6 is constant for a certain amount of fuel consumption, the amount of indoor air flowing into the exterior case 1 is reduced. Furthermore, the amount of air in the air passages 8 and 17 decreases, and the temperature above the cover plate 7 increases. And clogging detector 2
3, the detected temperature T is the predetermined operating temperature TP as shown in FIG.
When the amount exceeds that level, the microcomputer 26 increases the ratio of the rotation speed of the blower fan to the fuel consumption amount, as shown in FIG. 2, to compensate for the decrease in the air volume of the blower fan 6. Additionally, the filter lamp 29 is turned on to urge the customer to clean the air filter F.

In this way, when the air filter F becomes clogged, the rotational speed of the blower fan 6 is controlled to a high level, so that the decrease in the air volume of the blower fan 6 is compensated for, and the inside of the outer case 1 is temperature rise is suppressed. Therefore, the high limit switch 24 can be prevented from being activated unnecessarily, and combustion can be continued while encouraging the customer to clean the air filter and maintaining a good combustion state.

When the rotation speed of the blower fan 6 is increased to compensate for the decrease in air volume, the detected temperature T of the clogging detector 23 may fall below the operating temperature TP, as shown in FIG. Even in such a case, the microcomputer 26 keeps the rotation speed of the blower fan 6 high and keeps the filter lamp 29 lit. Such rotation speed control and lighting of the filter lamp 6 are canceled when the customer notices an abnormality in the air filter F and turns off the operation switch 21. Further, similar control is performed when the air suction port 2 is blocked by a curtain or the like.

Of course, if the air filter F is used as is without being cleaned, when the detected temperature of the high limit switch 24 reaches a certain temperature higher than the operating temperature of the clogging detector 23, the high limit switch 2
4 is activated. At this time, the microcomputer 26
At the same time, the air filter lamp 29 is switched from a lit state to a blinking state to notify the customer that the gas fan heater has been forcibly stopped.

[0025]

[Effects of the Invention] Since the present invention is constructed as described above, the rotation speed of the blower fan is controlled according to the amount of fuel consumed by the burner, which not only prevents an increase in operating noise when the room temperature rises. If the air filter becomes clogged, the ratio of the rotation speed of the blower fan to the fuel consumption is increased, compensating for the lack of air volume and suppressing the temperature rise inside the outer case, while also increasing the clogging detector signal. This improves usability by allowing the clogging indicator to continue operating regardless of the situation, allowing combustion to continue as much as possible while maintaining safety, and prompting customers to check for abnormalities.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of a control device for a gas fan heater to which the present invention is applied.

FIG. 2 is an explanatory diagram of control characteristics of the control device.

FIG. 3 is a time chart for explaining other control characteristics of the control device.

FIG. 4 is a schematic configuration explanatory diagram of a gas fan heater showing an example of a hot air heater.

[Explanation of symbols]

1 Exterior case 2 Air intake port 3 Warm air outlet 4 Combustion chamber 5 Gas burner 6　Blower fan F Air filter 19 Control device 23 Clogging detector

Claims (1)

[Claims] Claim 1: A burner is housed in an exterior case having an air inlet and a hot air outlet, a combustion chamber facing the burner, and a combustion chamber that supplies air sucked in from the air inlet to the burner and blows combustion gas with hot air. Equipped with a blower fan that discharges air from the outlet, an air filter at the air intake port, a control device that controls the amount of fuel supplied to the burner and the rotation speed of the blower fan, and adjusts the amount of fuel consumed by the burner. In the hot air heater, the control device has a clogging detector that detects clogging of the air filter and a clogging indicator, and when the clogging detector detects clogging, the control device adjusts the fan rotation according to the fuel supply amount. 1. A warm-air heater, characterized in that the hot-air heater is configured to increase the number ratio and to operate a clogging indicator independently of a signal from a clogging detector.