JPH01216498A - Thermal sensor and heat/smoke compound sensor - Google Patents

Abstract

PURPOSE:To eliminate an exposed metal part and to improve corrosion resistance by forming a thermal sensing part with a resin element whose electric resistance decreases according to temperature rise. CONSTITUTION:A thermal sensing part 1 is formed with the resin element whose electric resistance decreases according to the temperature rise, and an alternating current voltage is impressed to a sensor part S formed by serially connecting the thermal sensing part 1 to a resistance R mounted on a circuit board provided in a sensor A. In such a condition, the change of a voltage level generated at the sensor part S when the thermal sensing part 1 receives temperature change by the external temperature is detected by a voltage detecting circuit 5a, and an abnormal signal is outputted. Thus, the thermal sensor with the high corrosion resistance and high reliability can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in heat detectors and combined heat and smoke detectors.

[Prior Art] Conventional heat detectors of this type include fixed-temperature heat detectors that issue an alarm when the temperature exceeds a certain value, and differential heat detectors that issue an alarm only when the temperature rises rapidly to a certain extent. Utensils, etc. are becoming popular.

FIG. 9 shows the configuration of a differential heat sensor. When the temperature rises rapidly, the air inside the heat-sensitive chamber 100 expands, compressing the diaphragm 101 and closing the contact 103 to issue an alarm, but the temperature rises slowly. In response to such temperature changes, the leak hole 102 works to maintain parallelism with the external pressure and prevent false alarms from occurring.

Furthermore, as shown in FIG. 10, the conventionally used smoke detector includes a light emitting chamber 201 and a light receiving chamber 202 in a chamber 200 having a labyrinth structure. The light receiving chamber 202 detects scattered light from smoke that has entered the chamber 200 to obtain a signal corresponding to the smoke concentration.

However, because the heat detectors described above use many metal parts such as diaphragms, leak holes, and contacts, they have poor corrosion resistance even in normal usage environments, resulting in a decline in reliability. I'm there.

[Problem to be solved by the invention]

The present invention proposed to solve the above-mentioned problems provides a heat sensor and a heat smoke composite sensor with high corrosion resistance and reliability by reducing the number of metal parts and having a simple structure. [Means for Solving the Problems] The invention proposed to solve the above problems has the common feature that the heat sensitive part is formed of a resin material whose electrical resistance decreases as the temperature rises. The first invention proposed herein is characterized in that the heat sensitive part is formed of a resin material whose electrical resistance decreases as the temperature rises, and the heat sensitive part is mounted on a circuit board provided inside the sensor. While applying an alternating current voltage to the sensor section, which is formed by connecting in series the resistor or the heat-sensitive element whose electrical resistance decreases as the temperature rises,
A voltage detection circuit detects a change in the voltage level that occurs in the sensor section when the heat-sensitive section receives a temperature change due to an external temperature, and outputs an abnormality signal.

Further, in the second aspect of the present invention, a resin material whose electrical resistance decreases as the temperature rises is arranged on the inner and outer sides with an insulating layer in between to form a three-layer structure heat-sensitive section, and these inner and outer A sensor section is constructed by connecting resin layers in series, and when an AC voltage is applied to this sensor section, the voltage level generated at the sensor section when the heat sensitive section undergoes a temperature change due to external temperature. The structure is such that a voltage detection circuit detects the change and outputs an abnormal signal.

Furthermore, the first type of combined heat and smoke detector proposed at the same time as a heat detector is equipped with a light emitting element and a light receiving element inside a smoke detection chamber, and detects an abnormality when smoke flows into the smoke detection chamber. A heat-sensitive part is formed on the bottom surface of the smoke detection chamber of a photoelectric smoke detector that outputs a signal, and is made of a resin material whose electrical resistance decreases as the temperature rises. When an AC voltage is applied to the sensor section, which is formed by connecting in series a resistor mounted on the provided circuit board or a heat-sensitive element whose electrical resistance decreases as the temperature rises, the heat-sensitive section is exposed to the outside. The structure is such that a voltage detection circuit detects the change in voltage level that occurs in the sensor section when the temperature changes due to temperature, and outputs an abnormal signal. A photoelectric smoke detector is equipped with a light-emitting element and a light-receiving element inside, and outputs an abnormal signal when smoke enters the smoke detection chamber. A three-layer heat-sensitive section is formed by placing resin materials with low electrical resistance on the inside and outside with an insulating layer in between, and these inner and outer resin layers are connected in series to form the sensor section. When an AC voltage is applied to this sensor section, a voltage detection circuit detects a change in the voltage level that occurs in the sensor section when the heat-sensitive section receives a temperature change due to external temperature, and generates an abnormal signal. It is configured to output.

[Effect]

In the heat sensor of the first invention, when the sensor part is configured by combining a heat sensitive part made of a resin material whose electrical resistance decreases as the temperature rises and a resistor, it operates as a constant temperature heat sensor, Further, when the sensor section is configured by combining a heat-sensitive section made of the resin material described above and a heat-sensitive element such as a thermistor, it operates as a differential heat sensor.

Further, in the heat sensor of the second invention, the structure of the heat sensing part constituting the sensor part is a three-layer structure made of the above-mentioned resin material with an insulating layer in between, and operates as a differential heat sensor.

Furthermore, in the third invention and the fourth invention, a heat and smoke composite sensor is obtained in which a heat sensor and an optical smoke sensor each having the above-mentioned structural features are integrated.

In the embodiment of the present invention, an alternating current voltage is supplied to a sensor section that is constructed by combining a heat-sensitive section made of a resin material whose electrical resistance decreases as the temperature rises, and a resistor. This is to prevent the material from deteriorating due to effects such as electrolysis when direct current is applied to the resin material used in the part.

〔Example〕

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a structural diagram of a heat sensor according to an embodiment of the first invention, where 1 is a heat sensitive part formed of a resin material whose electrical resistance decreases as the temperature rises, 2 is a heat sensitive part 1 and a circuit board 5. 3 is the upper body of the thermosensor, 4 is a clip terminal for fixing the thermosensor to a base (not shown), and 4a is the clip terminal 4 connected to the upper body 3 of the thermosensor. A fixing screw is shown that fixes the circuit board 5 and transmits a signal from the board 5 to the clip terminal via the lead 2c.

FIG. 2 is a block diagram showing the internal configuration of the heat sensor A having such a structure. A part of the sensor S is formed. The sensor section S is provided with a third voltage by an AC voltage generating circuit 5C.
An AC voltage as shown in the figure is applied during monitoring, and in this state, the voltage detection circuit 5a detects a change in the voltage level occurring at point a of the sensor section S, and when the voltage level exceeds the specified value. When it exceeds the limit, the signal output circuit 5b outputs an alarm signal (the connection line with the fire receiver is short-circuited).

To explain in more detail the operating principle of the sensor of the present invention, when the AC voltage waveform applied to the sensor part S is shown by the solid line in FIG. When the potential at the connection point a of R is based on L, it becomes the voltage shown by the broken line in Figure 3. However, when the temperature rises, the electrical resistance of the resin material l decreases, so the potential at the connection point a The potential of the voltage decreases as shown by the dashed line a°, and when this voltage falls below a specified value, that is, when the temperature exceeds a certain - constant temperature, the signal output circuit 5b issues an alarm. It works.

In addition, in this example, the sensor section S includes a resin material 1 and a resistor R.
are connected in series, but a thermistor T is used instead of the resistor R.
If a heat-sensitive element such as H is used, when the temperature rises slowly, the resin material l and thermistor TH show similar resistance changes, so the potential at the voltage detection point a of the sensor part S hardly changes, so no alarm is issued. It is also possible to construct a differential heat sensor that issues an alarm only in response to a sudden rise in temperature.

Next, FIG. 4 is a structural diagram of a heat sensor according to an embodiment of the second invention, in which 1 and 1'' are resin materials whose electrical resistance decreases as the temperature rises. The insulation layer 6
A three-layered heat-sensitive section is formed by sandwiching the two layers.

In addition, 2 and 2' are the connection parts of the leads 2C and 2C that connect the resin materials 1 and 1' and the circuit components mounted on the circuit board 5, and 3 is the upper body of the heating device, and the conductive parts provided on the upper part of the body are It is fixed to a base portion (not shown) fixed to a ceiling surface or the like using a magnetic clip terminal 4.4.

FIG. 5 is a block diagram showing the internal structure of this heat sensor A corresponding to FIG. Form. 5a is a voltage detection circuit that detects a change in the voltage level occurring in the sensor section S, 5b is a signal output circuit that outputs an alarm signal when the voltage level of the voltage detection circuit 5a exceeds a specified value, and 5C is a sensor section S This is an AC voltage generation circuit that generates an AC voltage to be applied to the AC voltage.

In this example, the resin materials 1 and 1' are connected in series to the sensor section S, so if the temperature rises gradually, the potential at the voltage detection point a of the sensor section S will hardly change, so no alarm will be issued. First, it operates as a differential heat sensor that issues an alarm only in response to a sudden rise in temperature.

In addition, in the heat sensor of the present invention as described above, since the heat-sensitive section is formed of a resin material, the resin material 1.1"
Stability of the connection resistance of the connecting portion 2.2'' is required, but since it is not possible to solder directly to the resin material when connecting wiring, a method as shown in FIG. 6 is adopted.

That is, in the case shown in FIG. 6(a), a plating layer 2a is applied to the surface of the resin material 1 constituting the heat-sensitive part, a metal terminal 2b is crimped onto the plating layer 2a, and the conductor of the lead 2C is soldered or the like. In the sensor of the present invention, it is used for the connection between the heat sensitive part and the circuit board. Also, Figure 6 (
The method shown in b) is applied when electricity is applied to the resin material constituting the heat sensitive part, and the conductor or metal terminal 2d is embedded in the resin material 1 in advance and connected by a method such as soldering to the conductor of the lead 2c. It is something to do.

Next, the structure of the heat-smoke composite sensor, which is the third invention, will be explained using FIG. 7.

In the figure, 1 is a heat-sensitive part formed on the lower surface of the smoke sensing chamber 12 and made of the above-mentioned resin material, 2 is a connection part that electrically connects the resin material and the circuit board 5 via a lead 2C, 3 is the upper body of the heat and smoke composite detector, 4 is a clip terminal for fixing the main body to the base, 5 is a board on which circuit members of the heat sensitive circuit section are mounted, and 7 is mounted with circuit members of the smoke detection circuit section. The substrate, 8.9, is a light emitting element and a light receiving element placed in the smoke sensing chamber 12, and 10 indicates smoke intrusion light.

In such a heat-smoke composite sensor, each of heat and smoke is sensed independently, so as for the heat sensing circuit section, the sensor section S is made of a resin material and a resistor, as in the first embodiment of the invention. Alternatively, it can be configured by a combination of a resin material and a heat-sensitive element such as a thermistor.

Next, an embodiment of the heat-smoke composite sensor of the fourth invention will be described. In this example, in the heat-smoke composite sensor of the third invention described above (see Fig. 7), the sensor part has a three-layer structure in which an insulating layer is sandwiched between resin materials, similar to the embodiment of the second invention. It operates as a differential heat sensor.

In the heat smoke composite detectors of the third and fourth inventions described above,
Possible configurations include a case in which an alarm is issued when either one of the heat and smoke detection signals is detected, or an alarm is issued only when both detection signals are output. FIG. 8 is a diagram showing such a configuration. In FIG. 8a, an alarm signal is output when either the heat detection signal or the smoke detection signal is detected, and in FIG. It is configured to issue an alarm only when both the detection signal and the smoke detection signal are detected. Although not shown in the figure, it is also possible to adopt a configuration in which either the heat detection signal or the smoke detection signal is prioritized, taking into consideration the conditions under which the sensor is placed.

〔Effect of the invention〕

In any of the above-described configurations of the present invention, since a resin material is used for the heat-sensitive portion, there is no exposed metal portion and corrosion resistance is improved. Furthermore, since the heat-sensing portion also serves as an outer cover, the structure is simplified, and a more reliable heat sensor can be provided. Furthermore, this resin material has thermoplastic properties and can be injection molded and extruded.
Manufacturing becomes easier.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the internal structure of the heat sensor of the first invention, FIG. 2 is a block diagram showing its circuit configuration, FIG. 3 is an explanatory diagram of the operation of the sensor section, and FIG. An internal structural diagram of the heat sensor of the invention, FIG. 5 is a block diagram showing its circuit configuration,
Fig. 6 is an explanatory diagram of the connection part, Fig. 7 is an internal structural diagram of the heat-smoke composite detector of the third and fourth inventions, Figs. 8a and 8b are explanatory diagrams showing the configuration, and Fig. 9 is the difference. An explanatory diagram of a dynamic heat sensor,
FIG. 10 is an explanatory diagram of an optical smoke detector. [Explanation of symbols] 1.1°...Thermal sensing part 2.2゛...Connection part 3...Detector body 4...Clip terminal 5.7...Substrate 5a...Voltage detection circuit 5b... Signal output circuit 5C... AC voltage generation circuit S... Sensor part 6... Insulating layer 8... Light emitting part 9... Light receiving part

Claims (4)

[Claims] (1) The heat sensitive part is formed of a resin material whose electrical resistance decreases as the temperature rises, and the electrical resistance decreases with the temperature rise. A change in the voltage level that occurs in the sensor section when the heat-sensitive section receives a temperature change due to external temperature while applying an AC voltage to the sensor section formed by connecting the heat-sensitive element in series. A heat sensor configured to detect this using a voltage detection circuit and output an abnormal signal. (2) A three-layer heat-sensitive section is formed by placing resin materials whose electrical resistance decreases as the temperature rises on the inside and outside with an insulating layer in between, and these inner and outer resin layers are connected in series. A voltage detection circuit detects a change in the voltage level that occurs in the sensor section when the heat-sensitive section receives a temperature change due to external temperature while an alternating current voltage is applied to the sensor section. A heat sensor configured to detect and output an abnormal signal. (3) On the bottom surface of the smoke detection chamber of a photoelectric smoke detector, a light emitting element and a light receiving element are provided inside the smoke detection chamber, and an abnormal signal is output when smoke flows into the smoke detection chamber. The heat sensitive part is made of a resin material whose electrical resistance decreases as the temperature rises, and the heat sensitive part and the resistance mounted on the circuit board inside the sensor or the resistance that decreases as the temperature rises. Changes in the voltage level that occur in the sensor unit when the heat-sensing unit receives a temperature change due to external temperature while applying an AC voltage to the sensor unit formed by connecting the heat-sensitive element in series. A heat and smoke composite detector configured to detect with a voltage detection circuit and output an abnormal signal. (4) The bottom surface of the smoke detector chamber of a photoelectric smoke detector in which a light emitting element and a light receiving element are provided inside the smoke detection chamber, and an abnormal signal is output when smoke flows into the smoke detection chamber. A three-layer heat-sensitive section is formed by placing a resin material whose electrical resistance decreases as the temperature rises on the inside and outside with an insulating layer in between, and these inner and outer resin layers are connected in series. A voltage detection circuit detects a change in the voltage level that occurs in the sensor section when the heat-sensitive section receives a temperature change due to external temperature while an AC voltage is applied to the sensor section. A heat and smoke composite detector configured to detect and output an abnormal signal.