JP5236539B2 - Heat sensor - Google Patents

Description

  The present invention relates to a heat sensor for detecting a fire, and more particularly to a heat sensor having a non-contact temperature sensor.

  In a conventional heat sensor, a thermistor is provided on the surface of a housing, and a temperature is measured by bringing a thermal air current into direct contact with the thermistor (see, for example, Patent Document 1).

JP 2003-109141 A

  In the conventional example, in order to measure the temperature by directly exposing the thermistor to the hot air flow, the thermistor is provided so as to protrude from the casing. For this reason, if a rod or the like collides with the thermistor and an external force is applied, the temperature may not be measured due to deformation, or accurate temperature measurement may not be possible.

  Therefore, in order to protect the thermistor from external force, a protection structure (guard) for the thermistor is required. However, if this protection structure is provided, the entire heat sensor becomes thick, so the heat sensor is made thinner. Can not meet the request.

  In view of the above circumstances, an object of the present invention is to reduce the thickness of a heat sensor.

The present invention includes a main body, a casing that covers the main body and has a truncated cone-shaped portion, a heat absorption plate provided on a top surface of the truncated cone-shaped portion, and a position facing the inner surface of the heat absorption plate, A non-contact temperature sensor that is provided apart from the heat absorption plate and detects the temperature of the heat absorption plate; and a self-temperature sensor that is provided in the main body and detects the temperature in the housing, the non-contact sensor and the The fire is judged by detecting the temperature of the self-temperature sensor .

The heat absorbing plate of the invention is formed in a circular shape, it characterized that you have provided within directional range of the non-contact temperature sensor.

The self-temperature sensor according to the present invention is provided integrally with the non-contact temperature sensor .

  Since the present invention is configured as described above, the heat detector can be made thinner than the conventional example.

  Further, since the temperature is detected by using the thermopile as the non-contact temperature sensor and the thermistor as the self-temperature sensor, it is possible to detect the fire more accurately than when using only the thermistor.

  Furthermore, since the heat absorbing plate is made detachable, the sensitivity of the heat detector can be easily changed by selecting heat absorbing plates made of different materials.

It is a top view which shows 1st Embodiment of this invention. It is the II-II sectional view taken on the line of FIG. It is a top view which shows the main body of a heat sensor. It is a front view of the said main body. It is a perspective view which shows a use condition.

  The heat sensor 1 includes a main body 3 and a housing 5 that covers the main body 3. The main body 3 is formed in a disk shape from plastic and is installed on the ceiling surface via a base (not shown). A non-contact temperature sensor 7 is provided at the center of the main body 3. As this sensor 7, for example, a thermopile is used. The thermopile 7 is an infrared sensor that receives infrared rays emitted from an object and generates a thermoelectromotive force according to the amount of energy.

  The main body 3 is provided with a self-temperature sensor 9 integrally with the non-contact temperature sensor 7. As the sensor 9, for example, a thermistor is used. The thermistor 9 is a resistor that exhibits an extremely large resistance value change with respect to a temperature change. By providing both the sensors 7 and 9 integrally with the main body 3, the heat detector 1 can be further reduced in size.

  The housing 5 is made of plastic and includes a cylindrical portion 5a and a truncated cone portion 5b continuous to the cylindrical portion 5a. An endothermic plate 11 is provided on the top surface 5c of the truncated cone portion 5b. The endothermic plate 11 is easy to absorb the heat of a fire and is difficult to burn, such as aluminum or polyethylene terephthalate. It is formed by. The heat absorbing plate 11 is formed in a circular shape and is detachable.

  The heat absorbing plate 11 is disposed in parallel with the surface 3a of the main body 3, and the inner surface 11a faces the thermopile 7 with a gap t. The interval t is, for example, 5 mm, and is adjusted so that the heat absorbing plate 11 is positioned within the directing range S of the thermopile 7.

  The area (size) of the heat absorbing plate 11 is preferably set to a minimum size necessary for heat sensing. If the area is too large, the heat from the heat absorbing plate 11 is absorbed, so that the temperature in the housing 5 rises rapidly, and the temperature difference between the thermopile 7 and the thermistor 9 becomes small. Because it becomes impossible.

Next, the operation of this embodiment will be described.
The heat sensor 1 is attached to the ceiling surface of the fire monitoring area via a base (not shown), and the thermopile 7 and the thermistor 9 of the heat sensor 1 constantly monitor the temperature. That is, the thermopile 7 monitors the temperature of the heat absorbing plate 11 as the outside air temperature, and the thermistor 9 monitors the temperature inside the main body 3.

  When a fire occurs in the monitoring area, the temperature of the monitoring area rises and a hot air flow A flows along the ceiling surface. Therefore, the hot air flow A flows toward the top surface 5c while being guided by the frustoconical portion 5b of the housing 5 of the heat sensor 1, so that the heat absorbing plate 11 is heated by the hot air flow A and the temperature rises. The temperature of the heat absorbing plate 11 is measured by the thermopile 7 and the measurement result is transmitted to a control unit (not shown).

  At this time, the temperature of the main body 3 covered with the housing 5 is measured by the thermistor 9, and the measurement result is transmitted to the control unit.

The said control part compares the measured temperature of the thermopile 7 with the measured temperature of the thermistor 9, and judges whether it is a fire by the difference.
In this manner, since the fire is determined using the two types of temperature sensors 7 and 9, the fire can be determined more accurately than when only one type of sensor is used.

Since the heat absorbing plate 11 is detachably provided, the sensitivity of the heat detector 1 can be changed by replacing the heat absorbing plate 11 with a heat absorbing plate 11 made of a different material. For example, when it is desired to lower the detection sensitivity of the heat sensor 1, the heat absorption plate 11 is made difficult to transmit heat, thereby delaying the heat absorption plate 11 from warming and, as a result, making the detection of fire dull. I can do it.
In short, the sensitivity of the heat detector can be changed by replacing the heat absorbing plate 11 without adjusting the detection value of the heat detector.

  As described above, in the above-described embodiment, the thermopile 7 detects the temperature of the outside air, the thermistor 9 in the housing 5 detects the temperature in the housing 5, and compares these, based on the temperature rise. Although the fire determination is performed, it is possible to determine whether or not the fire is caused simply by the measured temperature of the thermopile 7 exceeding a predetermined temperature without using the thermistor 9.

  In this case, the housing 5 is not provided, and the heat absorbing plate 11 may be connected to the main body 3 via a support portion (not shown). Further, the thermistor 9 is not necessarily integrated with the thermopile 7, and may be provided directly on the main body.

DESCRIPTION OF SYMBOLS 1 Heat sensor 3 Main body 5 Case 7 Thermopile 9 Thermistor 11 Endothermic plate

Claims (3)

The body,
A housing that covers the body and has a frustoconical portion;
An endothermic plate provided on the top surface of the frustoconical portion ;
A non-contact temperature sensor that is positioned opposite to the inner surface of the endothermic plate and is separated from the endothermic plate to detect the temperature of the endothermic plate ;
A self-temperature sensor that is provided in the main body and detects a temperature in the housing;
A heat detector which makes a fire judgment by detecting temperatures of the non-contact sensor and the self-temperature sensor . The heat absorbing plate is formed in a circular shape, the heat detector of claim 1, wherein that you have provided within directional range of the non-contact temperature sensor. The heat sensor according to claim 1, wherein the self-temperature sensor is provided integrally with the non-contact temperature sensor .

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