JP2002133550A - Heat sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sensor conformable to the grasping of the extending state of an initial fire by use of a self fire alarm system. SOLUTION: In this heat sensor, the heat sensing output of a thermal element 4 arranged in a circuit part 3 within an outer case 2 so that its heat sensing part 5 is exposed from the surface of the outer case 2 is outputted as signal through the circuit part 3. A heat insulating part 6 filled with a resin heat insulating material having a heat resisting temperature higher than that of the mounting part of the circuit part 3 is provided between the circuit part 3 and the outer case 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat detector provided in an automatic fire alarm system.

[0002]

2. Description of the Related Art Conventionally, in an automatic fire alarm system installed in a building or the like (hereinafter referred to as a self-fire alarm system), a heat detector and a smoke detector are generally used as fire detectors. Smoke detectors are particularly effective for early detection of fires, and photoelectric smoke detectors are often used. That is, by using this photoelectric smoke detector, a fire can be found earlier, and the initial fire extinguishing can be quickly performed.

By the way, as a self-fire alarm system, analog data of physical quantity due to a fire from a fire detector having an address is received by a fire receiver, and a fire or non-fire is identified with high accuracy and a fire in a building is detected. There are those that provide information.
The photoelectric smoke detector used in this self-fire alarm system analyzes the detected smoke density change together with the smoke detection signal obtained by converting the analog amount corresponding to the physical amount of smoke into a digital signal, and detects the cause of the alarm. It determines whether it is a fire or a non-fire such as tobacco or water vapor and outputs a set accumulation time signal. This accumulation time signal shortens the time until a fire is determined when the possibility of a fire is high, and makes the time relatively long when it is determined that the possibility of a non-fire report is high. With such a variation, the occurrence of a fire can be detected earlier by preventing a non-fire report.

On the other hand, in the self-fire alarm system, a constant-temperature sensor and a differential sensor are connected to the same sensor line together with the photoelectric smoke sensor as a heat sensor having an address. This heat sensor is provided in a circuit portion in an outer case made of a synthetic resin so that the heat-sensitive portion is exposed from the surface of the outer case. The output is output as a signal through the circuit section. Therefore, when the installation environment reaches a predetermined temperature (for example, 60 ° C. or 70 ° C.), a heat detection signal is input to the fire receiver via the sensor line together with address data indicating the installation location. As a result, it is possible to input a fire signal by the photoelectric smoke detector from the fire receiver and to provide a fire notification including information on a fire occurrence location.

[0005]

By the way, recently, it has been required to confirm the spread of fire to the vicinity of the fire occurrence site in the early stage after the fire occurrence by using the above-mentioned self-fire alarm system. However, in the above-mentioned conventional technology, when a fire is reported, the circuit portion of the heat detector is damaged early by a high-temperature hot air flow caused by the fire.

That is, in general, the function of the self-fire alarm system is to notify the occurrence of a fire, and the heat detector guarantees that the air flow temperature around the installation environment exceeds about 70 ° C. is there. Therefore, components such as a resistor, a capacitor, a transistor, and a diode, which constitute a circuit unit that performs signal processing of a heat sensing output of the thermosensitive element, often have a specification of a heat-resistant temperature of 125 ° C. I have. For this reason, it was unable to withstand the high-temperature hot airflow in the early stage of the fire.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a heat detector capable of responding to the grasp of the expansion status of an initial fire by using a self-fire alarm system. It is in.

[0008]

In order to achieve the above object, in the heat detector according to the present invention, the heat sensitive portion is disposed on a circuit portion in the outer case such that the heat sensitive portion is exposed from the surface of the outer case. A heat sensor for outputting a heat sensing output of the heat-sensitive element as a signal through the circuit portion, wherein a resin having a heat-resistant temperature higher than the heat-resistant temperature of the mounted component of the circuit portion is provided between the circuit portion and the outer case. It is characterized in that a heat insulating portion filled with a heat insulating material is provided.

In this configuration, a circuit section in the outer case, which outputs a heat sensing output of a heat-sensitive element disposed so that the heat-sensitive section is exposed from the surface of the outer case, forms a circuit between the circuit section and the outer case. It is thermally protected by a heat-insulating portion provided therebetween, which is filled with a resin heat-insulating material having a heat-resistant temperature higher than the heat-resistant temperature of the mounted component of the circuit portion.

[0010] It is preferable that the heat insulating portion has a solid layer in which the resin heat insulating material covering the circuit portion is in a solid state, and a resin heat insulating material surrounding the solid layer is in a foamed state.
In this case, the circuit portion is thermally protected by a heat insulating portion having a solid layer in which the resin heat insulating material covering the circuit portion is solid, and the resin heat insulating material surrounding the solid layer having a foam layer in the foam state.

Further, it is preferable that the resin heat insulating material is made of the same resin material. In this case, a solid layer in which the resin heat insulating material is in a solid state and a foam layer in which the resin heat insulating material is in a foamed state are formed of the same resin material.

It is preferable that the circuit portion is disposed in the outer case so that at least the thickness around the solid layer is substantially uniform. In this case, the circuit portion is at least covered by a heat-insulating portion having a substantially uniform thickness of the solid layer with a substantially uniform thickness of the resin heat insulating material, and a foamed layer of the resin heat insulating material surrounding the solid layer. Thermally protected.

[0013]

1 to 3 show an embodiment corresponding to all of claims 1 to 4 of the present invention, and FIG.
FIG. 2 is a schematic configuration diagram illustrating a heat sensor according to an embodiment of the present invention, FIG. 2 is an explanatory diagram illustrating the operation of the heat sensor, and FIG. 3 is a schematic configuration diagram according to another example of the heat sensor. is there.

In the heat sensor 1 of this embodiment, a heat sensing output of a heat sensing element 4 provided in a circuit portion 3 in an outer case 2 so that the heat sensing portion 5 is exposed from the surface of the outer case 2 is provided. A heat sensor that outputs a signal through the circuit unit 3,
Between the circuit portion 3 and the outer case 2, a heat insulating portion 6 filled with a resin heat insulating material having a heat resistant temperature higher than the heat resistant temperature of the component mounted on the circuit portion 3 is provided.

Further, in the heat detector 1 of the embodiment, the heat insulating portion 6 is a solid layer 61 in which the resin heat insulating material covering the circuit portion 3 is in a solid state, and a resin heat insulating material covering the periphery of the solid layer 61. Has a foamed layer 62 in a foamed state. Further, in the heat detector of the embodiment, the resin heat insulating material is the same resin material. Further, in the heat sensor of the present embodiment, the outer case 2 is formed so that at least the thickness around the solid layer 61 is substantially uniform.
They are also located inside.

More specifically, the heat sensor 1 is a constant-temperature heat sensor having an address used in a self-fire alarm system described in the section of the prior art, and as shown in FIG. It has a case 2, a circuit portion 3 on which the heat-sensitive element 4 is provided, and a heat insulating portion 6, and a terminal fitting (not shown) provided on a substantially disk-shaped mounting base, which is provided on the upper surface side of the outer case 2. (Not shown) to be used by being attached to the ceiling surface.

The outer case 2 has a substantially disc-shaped upper opening having a small opening through which a heat-sensitive element 4 to be described later is inserted at the center thereof, and has a high heat resistance such as a heat-resistant ABS resin or polycarbonate resin material. It is formed of a resin material.
The outer case 2 has a substantially cylindrical inner peripheral wall 22 erected inside an outer peripheral wall 21 around the bottom plate.
A support rib 2 for supporting the circuit portion 3 is provided therein so that the thickness around the heat insulating portion 6 around the circuit portion 3 described later is substantially uniform.
3 are provided as appropriate. Therefore, the circuit portion 3 can be effectively heat-insulated and protected with a relatively small amount of resin heat-insulating material.

The circuit section 3 has a function of outputting a heat detection signal indicating the temperature around the installation environment of the heat sensor 1 to the fire receiver together with address data for specifying the heat sensor 1. The address data is output as a multiplex transmission signal together with digital data obtained by A / D conversion of the voltage signal of the heat sensing output of the thermal element 4. The transmission IC and the resistor, the capacitor, the transistor, the diode, and the like are configured. The circuit part 3 is formed by mounting the above components on a printed board 31 having high heat resistance, and the printed board 31 is provided with the terminal fittings and housed in the outer case 2.

In this case, the thermosensitive element 4 is formed of a thermistor element molded with epoxy resin including its lead. The heat-sensitive element 4 has a heat-sensitive portion 5
The tip provided with the thermistor element of
The circuit portion 3 is projected from the lower surface of the printed circuit board 31 so as to be exposed to the outside through a small opening provided at the center position of the circuit portion 3.

The heat insulating portion 6 protects the circuit portion 3 thermally and mechanically. In this case, the heat insulating portion 6 has a heat-resistant temperature higher than the heat-resistant temperature of the mounted component, and is formed of, for example, a urethane resin material. Have been. The heat insulating portion 6 is formed by filling a urethane resin material inside the inner peripheral wall 22 of the outer case 2 so as to cover the circuit portion 3. In this case, the solid heat insulating material covering the circuit portion 3 is a solid layer 61 in a solid state, and the resin heat insulating material surrounding the solid layer 61 is a foam layer 6 in a foam state.
2, the heat insulating portion 6 is formed of the same urethane resin material, and the solid layer 61 having a large heat capacity is filled so as to have a substantially uniform thickness so that the circuit portion 3 is thermally protected. Has become. Therefore, the solid layer 61 and the foam layer 62 are securely adhered to each other, and the circuit portion 3 can be protected more effectively.

In assembling the above-mentioned heat detector 1, first, the circuit section 3 is assembled with the heat-sensitive element 4 removed, and then the circuit section 3 is mounted inside the outer case 2, and then the outer case 2 is mounted. The thermosensitive element 4 is inserted from the lower side of 2 and soldered so as to hang down on the back side of the printed circuit board 31.
Above the bottom plate of the outer case 2, a heat-resistant sheet material serving as a mold for forming the solid layer 61 by first filling the urethane resin of the heat insulating portion 6 is provided. In the above state, a mold for molding is arranged inside the inner peripheral wall 22 and filled with urethane resin to form the solid layer 61. Then, the mold for molding is removed, and the solid layer 61 is removed. The foamed layer 62 is formed by foaming and curing the urethane resin so as to cover.

Next, with reference to FIG. 2, a description will be given of a temporal temperature change in the circuit section 3 when the heat detector 1 is mounted in a high-temperature hot air flow. FIG. 2A shows a hot air flow having a wind speed of 50 cm / sec, and FIG. 2B shows a hot air flow having a wind speed of 1 m.
In addition, the symbol A indicates a condition where the thickness of the solid layer 61 with a small filling amount of the urethane resin of the resin heat insulating material is small, and the symbol B indicates a thick condition of the solid layer 61 with a large filling amount of the urethane resin. It shows the temperature under the conditions. Further, in this confirmation experiment, the average temperature of the hot air flow was set to 198 ° C. assuming an actual fire, and the result is 600 seconds, that is, 10 minutes in the initial fire. From this graph, it can be seen that the thickness of the solid layer 61 has a greater effect on the temperature change than the difference in the wind speed of the hot air flow, and that the solid layer 61
It can be seen that even in the initial stage of a fire of about one minute, the temperature of the circuit part 3 can be set to 125 ° C. or less, which is the heat-resistant temperature of the mounted components constituting the circuit part 3.

At this time, the circuit portion 3 is covered with a solid layer 61 in which the resin heat insulating material is solid, and the resin heat insulating material surrounding the solid layer 61 is covered with a heat insulating portion 6 having a foamed foam layer 62. Therefore, the outer case 2 is first heated and heated by the hot air flow caused by the fire, and then the heat is transferred to the foam layer 6.
2. The solid layer 61 conducts heat in this order and is thermally protected, and the heat conduction is cut off to some extent by the foam layer 62. Further, since this heat conduction contributes to the thickness of the solid layer 61, the circuit portion 3 is covered with the solid layer 61 in which the resin heat insulating material is at least substantially uniform, and the resin heat insulating material is solid. The solid layer 61 temporarily and stably absorbs the heat, effectively delaying the heat conduction to the mounted components of the circuit section 3 in the early stage of the fire.

Therefore, according to the heat sensor 1 described above, the heat sensing output of the heat sensing element 4 arranged so that the heat sensing portion 5 is exposed from the surface of the outer case 2 is output as a signal. The circuit portion 3 is thermally protected by a heat insulating portion 6 provided between the circuit portion 3 and the outer casing 2 and filled with a resin heat insulating material having a heat resistant temperature higher than the heat resistant temperature of the mounted components of the circuit portion 3. Therefore, it is possible to use the self-fire alarm system to grasp the state of expansion of the initial fire.

Then, the circuit portion 3 is heated by the heat insulating portion 6 having a solid layer 61 in which the resin heat insulating material covering the solid layer 61 is in a solid state, and a resin heat insulating material surrounding the solid layer 61 having a foamed layer 62 in a foamed state. As a result, the heat conduction to the circuit section 3 can be temporarily delayed, so that the heat can be effectively protected. In addition, since the solid layer 61 in which the resin heat insulating material is in a solid state and the foam layer 62 in which the resin heat insulating material is in a foamed state are formed of the same resin material, the solid layer 61 and the foam layer 62 are securely adhered to each other and easily. Can be produced.

The circuit layer 3 covers at least the solid layer 61 having a substantially uniform thickness and a solid resin insulation material.
In addition, the resin heat insulating material covering the periphery of the solid layer 61 is thermally protected by the heat insulating portion 6 having the foamed layer 62 in the foamed state, so that the circuit portion 3 is uniformly and entirely thermally protected. Quality can be stable.

It should be noted that the present invention is not limited to the one shown in FIG. 3 in which the heat insulating portion 6 around the circuit portion 3 is constituted only by the foam layer 62 as shown in FIG. It goes without saying that various parts of the embodiment are included, such as a configuration in which the part 6 is made of a different material or an air layer is formed between the solid layer 61 and the foam layer 62.

[0028]

The present invention is embodied as in the above-mentioned embodiment. In the heat sensor according to the first aspect of the present invention, the self-fire alarm system is used to cope with the grasp of the expansion status of the initial fire. Can be.

Further, in the heat sensor according to the second aspect, the circuit portion is a solid layer in which the resin heat insulating material covering the circuit portion is solid, and the resin heat insulating material surrounding the solid layer is a foam layer in the foam state. Since the heat is thermally protected by the heat-insulating portion, the heat conduction to the circuit portion can be temporarily delayed, and the heat can be effectively protected.

Further, in the heat sensor according to the third aspect, since the solid layer in which the resin heat insulating material is solid and the foamed layer in which the resin heat insulating material is foamed are formed of the same resin material, the heat sensor is solid. The layer and the foam layer are securely adhered to each other, and thus can be easily produced.

In the heat sensor according to the fourth aspect of the present invention, the circuit portion covers at least the solid portion, the solid layer having a substantially uniform thickness and a solid resin insulation material, and a resin covering the periphery of the solid layer. Since the heat insulating material is thermally protected by the heat insulating portion having the foamed layer in the foamed state, the circuit portion can be thermally protected uniformly as a whole, and the quality can be stabilized.

[0032]

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a heat detector according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an operation of the heat detector.

FIG. 3 is a schematic configuration diagram according to another embodiment of the heat detector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat sensor 2 Outer case 3 Circuit part 4 Heat sensitive element 5 Heat sensitive part 6 Heat insulation part 61 Solid layer 62 Foam layer

Claims (4)

[Claims] 1. A heat sensor which outputs a heat sensing output of a heat sensing element disposed in a circuit portion in an outer case so that the heat sensing portion is exposed from a surface of the outer case via the circuit portion. A heat sensor, wherein a heat insulating portion filled with a resin heat insulating material having a heat resistant temperature higher than the heat resistant temperature of the mounted component of the circuit portion is provided between the circuit portion and the outer case. 2. The heat sensor according to claim 1, wherein the heat insulating portion has a solid layer in which the resin heat insulating material covering the circuit portion is in a solid state, and the resin heat insulating material surrounding the solid layer is in a foamed state. . 3. The heat detector according to claim 2, wherein said resin heat insulating material is made of the same resin material. 4. The heat sensor according to claim 2, wherein the circuit portion is disposed in the outer case so that at least a thickness around the solid layer is substantially equal.