JPH0634126A - Alarm device for hot air heater - Google Patents

Abstract

PURPOSE:To provide an alarm device for a hot air heater in which an operation sensing part of a blower can be eliminated, and both sensing of abnormal heating of the heater and sensing of abnormal state of the blower can be attained. CONSTITUTION:This hot air heater changes heat generated by a heater 2 into hot air with a blower 1 and sends it out. A temperature sensor 3 detects a temperature near the heater 2 and a temperature measuring circuit 4 measures a temperature near the heater 2 in reference to an output from the temperature sensor 3. Differential processing part 5 detects a time gradation of measured temperature in reference to an output from the temperature measuring circuit 4, and a control part 6 performs a controlling operation for the heater 2 in response to the output from the differential processing part 5 and further generates an alarm signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a warning device for a warm air blower, and more particularly to a warning device for a warm blower used in a warm air circulation type aerial snow melting device.

[0002]

2. Description of the Related Art As shown in the block diagram of FIG. 3, a conventional warm air blower includes a blower 1, a heater 2, an operation detector 7 for detecting the operation of the blower 1, and a thermostat 8 for detecting an abnormal overheat of the heater 2. have. Further, a control unit 6 for controlling these is prepared separately.

Next, the operation of the warm air blower will be described.
The blower 1 is first activated by a command from the control unit 6a. When the operation detector 7 confirms the operation of the blower 1, the heater 2 is turned on by the control of the controller 6a, and hot air is supplied to the air blower (not shown).

When the operation detector 7 detects that the blower 1 has stopped while the warm air blower is operating, or the thermostat 8 detects abnormal overheating of the heater 2, the controller 6a immediately sends the heater 2 a signal. The power supply is stopped to prevent the heater 2 from burning.

[0005]

This conventional hot air blower has the drawback that it requires two sensor units, a motion detecting unit and a thermostat, and in particular, the mechanism of the motion detecting unit is often complicated.

[0006]

According to another aspect of the present invention, there is provided an alarm device for a warm air blower, wherein the heat generated by the heater is turned into warm air by a blower and is sent to the hot air blower. A temperature sensor that detects the temperature of the temperature sensor, a temperature measurement circuit that measures the temperature near the heater from the temperature sensor output, a temperature measurement circuit that measures the temperature near the heater from the temperature sensor output, and the time of the measured temperature. A differential processing unit that detects a gradient and a control unit that controls the heater and generates an alarm signal in response to the differential processing unit output.

[0007]

The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. Figure 2
FIG. 4 is a diagram showing how the temperature rises in the vicinity of the heater 2 used in this embodiment.

Referring to FIGS. 1 and 2 together, this warm air blower has a blower 1 and a heater 2 similar to the warm air blower of the prior art.
To supply hot air to the air receiving device (not shown). First,
When the warm air blower is activated, the control unit 6 supplies power to the blower 1 and then to the heater 2. At this time, if all of the warm air blowers are normal, the temperature T measured by the temperature measuring circuit 4 by the signal from the temperature sensor 3 is b in FIG.
Rises like the curve of and exceeds temperature T _NRM , but temperature T
_Does not reach _ALM . Here, the temperature T _NRM is the outside air temperature T
It is a temperature obtained by adding the amount of heat by the heater 2 to _O , and is a temperature that must be reached at a minimum in normal times. on the other hand,
The temperature T _ALM is a temperature at which it can be determined that a further temperature increase is abnormal.

Next, when the heater 2 is energized without the blower 1 being started, the temperature sensor 3 detects a rapid temperature rise such as the curve of FIG.
The differential processing unit 5 for detecting the change (temperature time longitude) d _T / d _t of the temperature output from the temperature detected value equal to or higher than the preset allowable value of d _T / d _t , Judge abnormal rise. As a result, the control unit 6 stops energizing the heater 2 and outputs an alarm. Further, when the blower 1 suddenly stops from the normal state, the temperature in the vicinity of the heater 2 reaches the a curve from the b curve of FIG. 2 through the d curve, and the operation in this case is performed in the same manner as described above.

Next, when the heater 2 is broken,
The temperature in the vicinity of the heater 2 becomes the curve of FIG. At this time, since the temperature near the heater 2 does not reach the temperature T _NRM even after a certain period of time, the control unit 6 outputs an alarm.

Finally, when the heater 2 overheats due to abnormal heat generation for some reason, the temperature in the vicinity of the heater 2 changes as shown by the curve e in FIG. When T _ALM is exceeded, the control unit 6 outputs an alarm.

[0012]

As described above, according to the present invention, since the inclination of the temperature change with respect to the time (temporal inclination of the temperature) is measured, the obstacle due to the stop of the blower can be detected before the temperature near the heater reaches an abnormal level. . As a result, the alarm device of the warm air blower has an effect that not only the operation detecting portion of the blower is not required, but also one temperature sensor can simultaneously detect abnormal overheat and blower abnormality. .

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing how the temperature rises in the vicinity of the heater 2 used in this embodiment.

FIG. 3 is a block diagram of a conventional warm air blower.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Blower 2 Heater 3 Temperature sensor 4 Temperature measuring device 5 Differentiation processing part 6,6a Control part 7 Operation detection part 8 Thermostat

Claims (2)

[Claims] 1. An alarm device for a warm air blower, which sends heat generated by a heater to a hot air blower by a blower, wherein the alarm device for the warm air blower measures a temperature sensor for measuring a temperature in the vicinity of the heater, and a time for the measured temperature. An alarm device for a warm air blower, comprising: a temperature change detecting means for detecting a change. 2. An alarm device for a warm air blower which sends the heat generated by a heater into warm air by a blower, wherein the alarm device for the warm air blower detects temperature from the vicinity of the heater, and outputs from the temperature sensor output. A temperature measuring circuit that measures the temperature near the heater, a temperature measuring circuit that measures the temperature near the heater from the temperature sensor output, a differentiation processing unit that detects the time gradient of the measured temperature, and a differentiation processing unit output. And a control unit which controls the heater in response to the control signal and generates an alarm signal.