JPH0739885B2 - Air flow control method for hot air heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention controls the air volume of a warm air heater that heats the inside of a room by exchanging heat between combustion gas from a burner and room air sent by a fan. Regarding the method.

(B) Conventional technology A conventional hot air heater of this type is disclosed in, for example, Japanese Utility Model Publication No. 62-44268.
As disclosed in Japanese Patent Publication, a heat exchange device in which a burner, a combustion cylinder, a connecting body, a heat exchanger, and an exhaust box are sequentially coupled,
The heat exchange device includes a blower that supplies indoor air. Further, as shown in FIG. 9, after the blower is ignited, the temperature of the heated portion rises to a predetermined temperature (on set temperature), and after the fire is extinguished, the temperature of the heated portion reaches a predetermined temperature (off set temperature). Until the time when the air flow rate drops to 0, the blower was operated at an air volume corresponding to the load or at a set air volume to prevent excessive rise of the heat exchange device while preventing the generation of cold air.

(C) Problems to be Solved by the Invention In the hot air heater described above, the temperature of the heat exchange device changes greatly during ignition and extinguishment, so the thermal expansion of the components of the heat exchange device and the joints between these components. The metal noise of "Pishi, Pishi" or "Pin, Pin" was generated by the heat shrinkage. In particular, there is a drawback that the metallic noise becomes intense because abrupt temperature change is accompanied at the start or stop of air blowing.

This invention has been made in view of the above facts,
The purpose is to suppress the metallic noise generated during ignition or extinguishing.

(D) Means for Solving the Problems According to the present invention, in a warm air heater including a heat exchange device having a burner and a blower that supplies indoor air to the heat exchange device, after ignition, there is a delay. The operation of the blower is started, and the amount of air blown by the blower is increased when the temperature of the heated portion such as the heat exchange device rises to a predetermined temperature.

Further, in the present invention, in a warm air heater including a heat exchange device having a burner and a blower that supplies room air to the heat exchange device, after extinguishing a fire, a temperature of a heated portion such as the heat exchange device is predetermined. The amount of air blown by the blower was reduced at the time point when the temperature dropped, and then the operation of the blower was stopped.

(E) Operation In the method of claim 1, the cold air flow immediately after ignition is prevented, and the amount of air blown increases as the temperature of the heat exchange device rises. There is less metal sound. Further, unlike the conventional case, a rapid temperature change such as when the blower is suddenly operated at the set air volume is eliminated, and there is no concern that the metallic noise becomes loud when the air flow is increased.

Further, in the method of claim 2, since the amount of air blown is reduced in accordance with the temperature drop of the heat exchange device while preventing the generation of cold air, the temperature drop gradient becomes gentle and the metallic noise from the heat exchange device is reduced. Become. Further, unlike the conventional case, a sudden temperature change such as when the blower is suddenly stopped is eliminated, and there is no concern that the metallic noise becomes loud when the blown air amount is reduced.

(F) Embodiment Hereinafter, an embodiment of the present invention shown in the drawings will be described.

1 and 2 show an outdoor air supply / exhaust type hot air heater to which the present invention is applied, wherein (1) is a heat exchange device (3) having a burner (2), a blower (4), A heater main body accommodating a fuel pump (5) for feeding fuel oil from a fuel tank (not shown) to the burner (2), and (6) a wall (7)
Attached to the air supply passage (6A) and the exhaust part (6
(8) is an air supply duct (6)
The air supply pipe for guiding the outdoor air flowing into A) to the burner (2), (9) the exhaust gas that has finished heat exchange with the heat exchanger (13), and the exhaust passage (6B) of the air supply / exhaust pipe (6). ) Is an exhaust pipe. In the heater body (1), the indoor air sucked from the upper part of the back by the blower (4) is heated by heat exchange with the combustion gas in the heat exchange device (3), and the hot air outlet (10) at the lower part of the front is heated. Is discharged into the room as warm air. The heat exchange device (3) includes a burner (2), a combustion tube (11) having a combustion chamber inside, a connecting body (12), and a heat exchanger (1).
3) and an exhaust box (14), which are connected in sequence along the flow of combustion gas. Further, (15) is a burner fan that supplies the outdoor air from the air supply pipe (8) to the burner (2), (16) is a room temperature sensor, and (17) is attached to the exhaust box (14). A bimetal switch that turns on and turns off at 55 ° C or lower, and (18) is a control device.

As shown in FIG. 1, the control device (18) includes an operation switch (19), a temperature setting device (20), a combustion amount setting device (21), a room temperature sensor (16) and a bimetal switch (17), which is a microcomputer ( A burner control circuit (23) provided on the input side of the microcomputer (22) and driving the fuel pump (5), the burner fan (15), etc. in a predetermined sequence on the output side of the microcomputer (22), and a blower (4). And a rotation speed control circuit (24) for controlling the amount of blown air.

When the combustion amount setter (21) is set to "automatic" during normal combustion, the microcomputer (22) shows the temperature difference between the temperature set by the temperature setter (20) and the temperature detected by the room temperature sensor (16). Burner control circuit (23) to determine the amount of combustion according to Fig. 4 and obtain the amount of combustion.
Send a signal to. Further, as shown in FIG. 5, a signal is sent to the rotation speed control circuit (24) so as to obtain a warm air volume (HL) corresponding to the combustion volume, and the air volume of the blower (4) is controlled. Further, when the combustion amount setter (21) is set to either "strong", "medium", or "weak", both control circuits (23) (24) are provided so that the respective combustion amount and warm air amount can be obtained. Send a signal to.

Further, the microcomputer (22) controls the air flow rate of the blower (4) at the time of ignition and extinguishing as follows. First, at the time of ignition, a timer for a predetermined time is set as shown in FIG. Keep the blower (4) stopped to prevent cold air from blowing into the room. Then, after a lapse of a predetermined time, the blower (4) is operated at the minimum air volume (L) regardless of the combustion amount, and a rapid temperature rise of the heat exchange device (3) is suppressed. After that, the wall temperature of the exhaust box (14) rises above a certain temperature (on-temperature of the bimetal switch (17)),
When the bimetal switch (17) is turned on, the blower (4) sets the air flow rate to an air flow rate (H to L) commensurate with the combustion rate, and the normal operation is started.

On the other hand, when extinguishing the fire, as shown in FIG. 7, the blower (4)
The operation is continued with the air volume of No. 2 set to the air volume set before extinguishing, and the temperature of the heat exchange device (3) is lowered. And the exhaust box (1
When the wall temperature of 4) becomes equal to or lower than a predetermined temperature (off temperature of the bimetal switch (17)), the amount of air blown by the blower (4) is reduced to the minimum amount, and the heat exchange device (3) continues to radiate heat. At this time, a timer for a predetermined time is set, and the blower (4) is stopped after the timer expires.

According to this embodiment, as shown in FIG. 8, the temperature change gradient of the heat exchange device (3) at the time of ignition and extinction becomes gentler than that of the conventional one shown in FIG. It is possible to suppress the generation of metallic sound due to thermal expansion and thermal contraction. In particular, since the temperature change in the portions C and D in FIG. 8 is smaller than that in the portions A and B in FIG. 9, it is possible to significantly suppress the generation of metallic noise at this point. of course,
While the temperature of the heat exchange device (3) is low, the blower is stopped or the operation is performed with the minimum air volume, so that there is no concern that cold air will be blown into the room.

(G) Effect of the Invention As described above, the present invention, when igniting or extinguishing a fire, prevents the blowing of cold air and, when the temperature of a heated portion such as a heat exchange device reaches a predetermined temperature, is a boundary. Since the air volume of the blower is increased or decreased, the temperature change gradient of the heat exchange device can be made gentle to reduce metal noise generated from the heat exchange device, and comfortable warm air heating with less noise. Can be realized.

[Brief description of drawings]

1 to 8 relate to an embodiment of the present invention, and FIG. 1 is a block diagram of a controller for a warm air heater,
FIG. 2 is a side view of the warm air heater in the installed state, FIG. 3 is an explanatory view of the internal structure of the warm air heater, FIG. 4 is an explanatory view of load-combustion amount characteristics, and FIG. 5 is a combustion amount-temperature. Explanatory drawing of air volume characteristics,
FIG. 6 is a flow chart for explaining the operation at the time of ignition of the microcomputer, FIG. 7 is a flow chart for explaining the operation at the time of extinguishment of the microcomputer, and FIG. 8 is an explanatory view of the temperature change characteristics of the heat exchange device. , FIG. 9 is an explanatory diagram of temperature change characteristics of a conventional heat exchange device. (2) …… Burner, (3) …… Heat exchange device, (4) ……
Blower, (14) …… Exhaust hood (heated part), (17)…
… Bimetal switch, (22) …… Microcomputer.

Claims (2)

[Claims] 1. A warm air heater comprising a heat exchange device having a burner and a blower for supplying indoor air to the heat exchange device, after the ignition, delaying the start of operation of the blower,
A method for controlling the air volume of a warm air heater, wherein the air volume of the air blower is increased at a time point when the temperature of a heated portion such as a heat exchange device rises to a predetermined temperature. 2. A hot air heater including a heat exchange device having a burner and a blower for supplying indoor air to the heat exchange device, wherein the temperature of a heated portion such as the heat exchange device is at a predetermined temperature after extinguishing the fire. A method for controlling the air volume of a warm air heater, which comprises reducing the air flow rate of the blower at a time point when the temperature drops to 0, and then stopping the operation of the blower.