JP2526373Y2 - Semiconductor heat detector - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a semiconductor type heat sensor which senses heat generated in a fire by using a change in electric resistance with respect to a temperature of a semiconductor.

[Prior Art] FIG. 4 shows an example of a conventional semiconductor heat sensor of this type described in, for example, JP-A-63-133292.

4 (A) and 4 (B), reference numeral 1 denotes a body, and 2 denotes a printed circuit board mounted on the body 1. Numeral 3 denotes a thermistor whose lead portion is provided upright from the printed circuit board 2 and whose tip is coated with a heat-sensitive portion of a spherical thermistor 3. Reference numeral 4 is a conical cover attached to the body 2.
Reference numeral 5 denotes a cylindrical protector, and reference numeral 6 denotes a knob protruding radially from the peripheral surface of the protector 5. The side surface of the protector 5 is open so as to surround and protect the thermistor 3 inside the cylinder.

In the heat detector having such a configuration, the body 1 is mounted on the ceiling surface via the mounting device with the thermistor 3 facing the floor surface. When a fire occurs, the surrounding temperature rises,
The electric resistance of the thermistor 3 changes in response to the temperature rise. As a result, a fire alarm is issued using the change in the electric resistance of the thermistor 3.

[Problem to be Solved by the Invention] As is well known, a thermistor having a small heat-sensitive portion has a property that the heat time constant is fast and responds to a slight change in surrounding heat. For this reason, if a protector is provided near the thermistor, heat will be absorbed and response characteristics will be reduced.
However, removing the protector is not preferable because fingers and instruments come into contact with the thermistor during maintenance and inspection, which lowers the detection sensitivity and breaks the lead. Can not. Therefore, special consideration is required for the arrangement of the protector and the like around the main body of the thermistor.

On the other hand, in the conventional semiconductor heat sensor, the thermistor 3 is surrounded by the cylindrical protector 5 as described above, and substantially no consideration is given to the response characteristics of the thermistor due to heat absorption. That was the actual situation. For this reason, a part of the protector is too close to absorb heat and the response characteristics are deteriorated, so that the protector does not operate at the set temperature or there is a problem that a report is lost.

The present invention has been made to solve the above-mentioned problems of the conventional semiconductor heat sensor.In particular, the structure of the protector has been improved to send a hot airflow free from turbulence and the like to the semiconductor, and a thermistor. It is an object of the present invention to provide a semiconductor heat sensor which forms and protects a space as large as possible around the device and which does not affect response characteristics.

[Means for Solving the Problems] The semiconductor heat sensor of the present invention includes an annular outer peripheral portion, a conical heat collecting portion that is convex toward the semiconductor side, and the heat collecting portion and the outer peripheral portion. The protector includes a plurality of radial legs connected to each other and a plurality of claws extending from the heat collecting portion toward the center. A space is provided around the semiconductor mounted so as to protrude below the mounting base, and the semiconductor is surrounded and protected by the protector via this space.

[Operation] A certain space is formed around the semiconductor, and the semiconductor device is protected under the semiconductor by a protector provided at an equal and maximum necessary distance. On the other hand, when the ambient temperature rises due to the occurrence of a fire, the hot air flow is rectified from below and is guided toward the semiconductor along the conical heat collector. Also, the hot air flow from the horizontal direction flows in from the openings between the radial legs, and flows out near the gap between the opposing legs. The hot airflow that has flowed into the protector in this way heats the semiconductor, changes the resistance value, and sends out a fire signal to a receiver or the like.

[Embodiment of the Invention] In FIGS. 1 and 2, 1 is a body, 2 is a mounting base,
Reference numeral 3 denotes a printed circuit board constituting the circuit unit 30, and 4 denotes a lead unit 5.
Is a thermistor soldered to the printed circuit board 3 through the insertion hole 6. The mounting base 2 is provided with a plurality of locking pieces 8 protruding upward.
The printed circuit board 3 is fixed by engaging with a locking hole 9 provided correspondingly to.

Reference numeral 7 denotes a protector for protecting the thermistor 4, and reference numeral 70 denotes four small screws for attaching and fixing the protector 7 to the mounting base 2. Reference numeral 71 denotes an outer peripheral portion of the protector 7, 72 denotes a conical heat collector that is convex toward the thermistor 4 side, and 73 denotes an outer peripheral portion 71 of the heat collector 72.
Eight radial legs 74 which stand up from the center axis and are connected to each other, and 74 are four plate-like claws extending in the centripetal direction from the inner peripheral surface of the heat collector 72 (FIG. 2). The heat collecting section 72 is formed so as to guide a hot air flow caused by a fire from below or on the side of the heat sensor to the thermistor 4 to improve the thermal response. Further, the number of the legs 73 is an optimal number so that a finger or a tool does not touch the inside of the thermistor 4 from the outside.
The circular space a formed by the tip of 74 is also selected to have the same function. In particular, the thermistor 4 is separated from the heat collecting portion 72 of the protector 7 by substantially the same distance as the claw portion 74, and a lower space A centered on the position of the thermistor 4 is formed below the same.

Reference numeral 11 denotes an annular wall provided at the center of the mount 2, reference numeral 12 denotes an outer peripheral wall, and reference numeral 13 denotes a filler injected into the annular wall 11. 14 is an annular step provided on the inner peripheral surface of the body 1;
And a plurality of protruding portions provided below the step portion 14 in the central axis direction. Reference numeral 16 denotes an engagement portion provided on the periphery of the mounting base 2 in alignment with the projection 15, and 17 denotes a groove provided on the periphery of the printed circuit board 3 aligned with the projection 15. Reference numeral 18 denotes two mounting screws that penetrate the body 1 and constitute a part of an electric circuit, and 19 denotes a plate-shaped nut fixed to the printed circuit board 3 and screwed to the mounting screw 18.

The configuration of the circuit section 30 described above is shown in FIG.
In FIG. 3, 31 is a heat detection circuit, 32 is a control circuit, and 33 is a switching circuit. The heat detecting circuit 31 converts the ambient temperature detected by the thermistor 4 into an electric signal and outputs the electric signal to the control circuit 32. Further, the control circuit 32 sequentially stores and calculates the input signal,
The switching circuit 33 is driven when the ambient temperature reaches a certain value or when the temperature change per unit time reaches a certain value. Reference numeral 34 denotes a constant voltage circuit that supplies a constant voltage to the heat detection circuit 31 and the control circuit 32, and reference numeral 35 denotes a non-polarizing circuit including, for example, a diode bridge. When the heat sensor is of an analog type, a signal transmitting / receiving circuit is provided instead of the switching circuit 33.

The semiconductor heat sensor of the present invention having the above-described configuration is assembled as follows.

First, the mount 2 and the protector 7 are overlapped and fixed with four small screws 70. The locking piece 8 of the mounting base 2 to which the protector 7 is fixed is connected to the printed board
Into the locking hole 9 of the first. Next, the lead portion 5 of the thermistor 4 is passed through the insertion hole 6 of the mounting base 2, and then the leading end is passed through the soldering hole of the printed circuit board 3. Subsequently, the protector 7 is placed on a jig for soldering, and the lead 5
Is soldered to the conductive print on the printed circuit board 3. By using a jig for soldering, the mounting base 2 of the thermistor 4
And so on. As a result, the position of the thermistor 4 is selected to be the same distance from the heat collecting part 72 and the claw part 74 of the protector 7, so that a fixed space A centered on the thermistor 4 is formed and fixed below the mounting base 2. . When the thermistor 4 is connected, a filler 13 for protection and sealing is filled in the annular wall 11 from an injection hole (not shown) of the printed circuit board 3. After the injected filler 13 is solidified, the mounting base 2 or the like to which the thermistor 4 is attached is pushed from below into the body 1 by using the step 15 to pass the groove 17 of the printed circuit board 3 through the protrusion 15 of the body 1. And fit them together.
At this time, the height of the annular wall 11 is made higher than the outer peripheral wall 12, and the printed board 3 is bent so that the periphery of the printed board 3 and the engaging portion 16 of the mounting base 2 are connected to the step portion 14 and the projecting portion 15. Between them elastically. After that, the mounting screw 18 is inserted into the hole of the body 1 and screwed into the nut 19 to fix the printed circuit board 3.
Is securely fixed to the body 1, and the main body of the heat detector is assembled. The heat sensor assembled in this way is attached to a ceiling and is detachably mounted on a wired base (not shown) by being slightly rotated from below using a mounting screw 18. When the heat sensor is mounted on the ceiling, the thermistor 4 soldered to the printed circuit board 3 is electrically connected to a receiver, a repeater, or the like via a mounting screw 18 serving as an input / output terminal.

Now, when a fire occurs indoors, the surrounding temperature rises, and the hot air flow rises toward a heat sensor mounted on the ceiling. Part of the rising hot air flow is the claw of protector 7.
The turbulent flow and eddy current are rectified by the conical heat collecting portion 72 having 74 and the speed thereof is increased. In addition, the hot air flow from the horizontal direction flows in from the opening between the radial legs 73 and flows out near the gap between the opposing legs 73. The hot airflow that has flowed into the protector 7 in this way heats the thermistor 4 and reduces the electric resistance in accordance with the temperature change of the hot airflow. The change in the resistance value of the thermistor 4 is detected by the heat detection circuit 31 as a temperature change accompanying the occurrence of a fire. When the change in the ambient temperature, that is, the change in the electric resistance becomes equal to or more than a predetermined value, the control circuit 32 turns on the switching circuit 33 and the fire signal is received via the mounting screw 18 constituting the output terminal. Is sent to the device.

When the body 1 of the heat sensor mounted on the ceiling is rotated in the opposite direction, the body of the heat sensor can be removed from the base. Then, after the mounting screw 18 is loosened and pulled out of the body 1, the mounting base 2 is detached from the projecting portion 15 of the body 1 and separated. As a result, the conductive surface side of the printed circuit board 3 is opened, so that dust adhering to the conductive surface can be removed, and a continuity test of the circuit element 30 can be performed.

In the above-described embodiment, the case where the thermistor 4 is used as the heat-sensitive element has been described as an example. However, a semiconductor other than the thermistor may be used as long as the electrical characteristics change according to the temperature. Further, the case where the electric resistance decreases as the temperature increases has been described, but a semiconductor having a negative temperature gradient can be used. Further, although the fixed space A is formed on the lower surface of the semiconductor by the protector 7, a fixed space may be provided around the thermistor (semiconductor) including the mounting base 2 side. Further, the mounting base 2 and the protector 7
Are fixed by the small screws 70, but may be configured to be detachable from the mounting base 2 or the body 1 using hooks according to the connecting means of the mounting base 2 and the printed circuit board 3.

[Effects of the Invention] According to the present invention, a circular heat collecting portion having an annular outer peripheral portion, a convex claw portion on the semiconductor side, and a plurality of radial connecting portions between the heat collecting portion and the outer peripheral portion. And a plurality of claws extending from the heat collecting portion toward the center. Then, a fixed space centered on the semiconductor was provided, and the semiconductor heat sensor was protected by the semiconductor being surrounded by the protector via this space. As a result, unlike the conventional case, a part of the protector does not absorb the heat so much that the response characteristics do not deteriorate, and the protector does not malfunction. Not only does a finger or a tool not come into contact with the semiconductor and a failure does not occur, but also a uniform heat flow can be sent to the heat-sensitive part by the heat collecting part of the heat collecting part protector.

Therefore, according to the present invention, it is possible to provide a semiconductor heat sensor having various characteristics such as excellent response characteristics and high detection sensitivity.

[Brief description of the drawings]

FIG. 1 is an explanatory view of the configuration of the embodiment of the present invention, FIG. 2 is an explanatory view of the configuration of the main body of the heat detector, (A) is a bottom view, (B) is a side view, (C) is a top view, and FIG. FIG. 4 is a block diagram showing the configuration of a circuit unit, and FIGS. 4A and 4B are explanatory diagrams of the configuration of a conventional heat sensor. 1 and 2, 1 is a body, 2 is a mount, 3 is a printed circuit board, 4 is a thermistor (semiconductor), 5 is a lead part,
6 is an insertion hole, 7 is a protector, 8 is a locking piece, 9 is a locking hole, 10 is a hook, 11 is an annular wall, 12 is an outer peripheral wall, 13 is a filler, 14 is a step portion, 15 is a protruding portion, 16 is the engaging part, 17 is the groove, 18
Is a mounting screw, 19 is a nut, 30 is a circuit part, 31 is a heat detection circuit, 32 is a control circuit, 33 is a switching circuit, 34 is a constant voltage circuit, 35 is a non-polarizing circuit, 70 is a small screw, and 71 is the outer periphery. Department, 72
Is a heat collecting portion, 73 is a leg portion, 74 is a claw portion, a is a circular space, and A is a fixed space.

Claims (2)

(57) [Scope of request for utility model registration] 1. A semiconductor heat sensor for detecting the occurrence of a fire by sensing heat using the temperature characteristics of a semiconductor, comprising: a mounting base protruding and mounting the semiconductor on a central axis; A protector that is attached and surrounds and protects the periphery of the semiconductor via a space portion, and the protector has a hollow portion facing the semiconductor with a hollow portion facing the semiconductor and having a hollow conical shape convex toward the semiconductor side. A semiconductor-type heat sensor comprising a heating unit. 2. A semiconductor heat sensor for detecting the occurrence of a fire by sensing heat using the temperature characteristics of a semiconductor, comprising: a mounting base protruding and mounting the semiconductor on a central axis; A protector that is attached and surrounds and protects the periphery of the semiconductor through a space, and protects the protector with an annular outer peripheral portion connected to a peripheral portion of the mounting base; A plurality of plate-shaped claws extending concentrically and extending from the inner peripheral surface in the centripetal direction are formed, and the hollow portion is opposed to the semiconductor, and a convex hollow conical heat collector is formed on the semiconductor side. And a plurality of radial legs that are connected to the heat collecting portion by rising from the outer peripheral portion on a central axis.