JPH09259376A - Heat sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sensor capable of fetching more hot air flow by a fire to the side of a semiconductor for heat sensing in the sate of surely protecting the semiconductor for the heat sensing such as a thermister or the like by a protector and preventing the attraction of dust by electrification. SOLUTION: This heat sensor B is provided with a heat sensor main body 1 incorporating circuit or the like, the thermister 2 and the protector 10 for surrounding the termister 2. The protector 10 is composed of peak part 11 arranged on the termister 2 and fins 12 radically arranged around the termister 2. The peak part 11 is turned to a cylindrical shape whose inner diameter and outer diameter are made smaller as going down and the fins 12 are provided with expanded expansion parts 12a on the outer side of the peak part 11. An air flow from an upper part is converged to the side of the thermister 2 at the time of being passed inside the peak part 11. The air flow abutted to the outer peripheral surface of the peak 11 is guided to the side of the thermister 2 by the inclination. The air flow abutted to the expansion part 12a is guided to the side of the peak part 11 by the expansion part 12a and guided to the side of the thermister 2 by the outer peripheral surface of the peak part 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat detector for detecting the occurrence of fire by detecting the heat generated by the fire.

[0002]

2. Description of the Related Art Generally, a semiconductor thermal sensor using a thermistor (semiconductor) whose electric resistance changes according to a change in temperature is known for detecting heat generated by a fire. Such a semiconductor type heat sensor is shown in FIGS.
Those shown in are already known. In addition, FIG.
In FIG. 7, the heat sensor A is shown with the side generally attached to the ceiling face down. That is, although the heat sensor A is shown upside down as it is actually used, in the following description of the heat sensor A, the upside down state will be described.

As shown in FIG. 5, the heat detector A has a short cylindrical heat detector body 1 having a built-in circuit for fire detection, and an upper portion (actually, from the center of the heat detector body 1). In this arrangement, the thermistor (heat sensing portion) 2 is provided extending downward and a protector 3 attached to the heat sensor body 1 so as to surround the thermistor 2. The protector 3 allows the heat flow generated by the fire to pass to the thermistor 2 side to some extent,
It is designed to protect the thermistor 2.

It should be noted that when the heat detector A is attached or detached or other work is performed during maintenance or the like, if the thermistor 2 is touched by a finger or an instrument, the sensitivity of the thermistor 2 may be deteriorated. At the same time, the lead 2a connecting the thermistor 2 and the heat detector body 1 may be broken. Therefore, in the heat detector A, the protector 3 that protects the thermistor 2 is attached as described above.

Conventionally, the protector 3 is the thermistor 2
The fins 4 arranged radially around the thermistor 2 to protect the side surface of the thermistor 2 and the circles arranged above the thermistor 2 to protect the upper surface of the thermistor 2 with a space around the thermistor 2. It has a plate-shaped top 5. As shown in FIGS. 6 and 7, the fins 4 are formed in a substantially right-angled triangular shape, and as shown in FIG. 8, for example, six fins 4 are radially arranged at equal intervals around the thermistor 2. It is arranged.

Further, the substantially triangular fin 4 has its bottom side joined to the heat detector body 1 side, and the side on the thermistor 2 side is formed substantially vertically with a gap from the thermistor 2. In addition, the outer side of the fin 4 is an oblique side that spreads outward as it goes downward. Further, the outer side of the fin 4 has a disk-shaped top 5 at its upper end.
Is connected to the outer peripheral edge of the top edge of the top portion 5 and the position of the upper end of the outer side is substantially aligned with the outer peripheral edge of the top part 5.

Further, between the fins 4 ...
The spacing is set so that instruments and fingers cannot easily enter.
The top portion 5 is formed with a plurality of holes 6 so that the hot air flow can pass from the upper surface side to the thermistor 2 side.
For example, as shown in FIG. 6, FIG. 7 and FIG.
It is composed of two annular outer peripheral portions 5a and an inner peripheral portion 5b arranged concentrically, and the holes 6, 6 are formed between the outer peripheral portion 5a and the inner peripheral portion 5b and inside the inner peripheral portion 5b. ing.

The outer peripheral portion 5a and the inner peripheral portion 5b are joined by ribs (not shown). With such a protector 3, the thermistor 2 is protected so that a finger, an instrument, or the like does not come into contact with the thermistor 2 in a state where a hot air flow generated by a fire can pass through.

[0009]

By the way, in the heat detector A having the protector 3 described above, when a hot air flow comes from the upper side of the thermistor 2, as shown by an arrow in FIG. The hot airflow that has not passed through the holes 6 collides with the top portion 5 and is scattered. Further, the hot air flow passing through the holes 6 and 6 of the top 5 does not always hit the thermistor 2, and at least a part of the hot air flow passing through the holes 6 and 6 of the top 5 does not hit the thermistor 2 and the fin 4 There is a possibility that it will come out from between.

Further, when the hot airflow comes from the side of the thermistor 2, the hot airflow which can pass between the adjacent fins 4 and 4 as shown by the arrow in FIG.
However, the hot air flow passing between the top portion 5 and the thermistor 2 passes over the thermistor 2 without hitting the thermistor 2. In addition, the arrow in FIG.
Of the heat flow coming from the side of the thermistor 2, it shows the heat flow in the vicinity of the height of the apex 5, and passes between two adjacent fins of such a heat flow, and 5
Although the hot air flow passing directly under the head of the thermal head goes directly to the center of the protector 3, it passes above the thermistor 2 and thus passes over the thermistor 2.

Most of the hot air flow colliding with the outer peripheral surface of the top portion 5 changes its direction along the outer peripheral surface of the top portion 5 and leaves the thermistor 2. Further, the hot air flow passing through the outside of the top 5 passes through the upper side of the hypotenuse of the fins 4 as it is and does not go to the thermistor 2 side. When the thermistor 2 is protected by the protector 3 as described above, the protector 3 may block a part of the air flow due to the heat of the fire or may direct the air flow away from the thermistor 2. As a result, , Heat detector A
There was a problem that the sensitivity of was reduced.

In order to efficiently take in the heat flow into the thermistor 2, it is conceivable to reduce the number of fins 4 ... Of the protector 3 or reduce the thickness of the fins 4 ... Or the top 5. To be However, when the number of fins 4 ... Is reduced, the distance between the fins 4 becomes large, and it becomes easy for fingers, instruments, etc. to enter between the fins 4, and the protector 3 cannot sufficiently protect the thermistor 2. It will be in a state.

Further, the heat sensor A is tested during maintenance for whether or not it is actually heated to operate. Therefore, when the thickness of the fins 4 ... There was a possibility that the fins 4 and the top portion 5 would immediately reach a high temperature and melt. On the other hand, the heat detector A has the protector 3
Also, static electricity is generated due to friction between the heat sensor main body 1 and the air flow, etc., and the dust is absorbed. Also, the heat sensor A
Since it is used for a long period of time while being attached to the ceiling of a building, etc., it continues to adsorb dust, resulting in a problem that the appearance becomes dark and the aesthetics of the room is impaired.

Therefore, the heat sensor A was wiped and cleaned at the time of maintenance and inspection, but as described above, the protector 3 portion is provided with the fins 4 at intervals such that fingers are difficult to enter and the top portion 5 is provided. Since the holes 6 and 6 are also provided, it has a shape that is extremely difficult to wipe off, and it takes a lot of time to wipe off. Further, the stains on the heat sensor A cannot be easily removed by wiping it off, and there is a problem that the heat detector A is not so clean despite the time and effort required.

Further, the heat sensor A may be mounted in a large number in a relatively large building and is also likely to be mounted in a relatively high position, so that there is a problem that a large amount of labor is required for wiping work. there were.
Further, by preventing the heat sensor A from being charged, it is possible to prevent dust from being adsorbed and prevent the heat sensor A from being contaminated to some extent. Therefore, it is possible to prevent stains by spraying or applying an antistatic material to the heat sensor A, but simply spraying or applying an antistatic agent does not provide a long-lasting antistatic effect. There was a problem.

Therefore, in order to prevent the heat detector A from being contaminated by the antistatic agent, it is necessary to frequently spray or apply the antistatic agent, which is a labor-intensive problem. Furthermore, in a waterproof fire detector used in a high humidity place, the fire detector itself may get wet due to the high humidity, and a film with an antistatic agent is formed on the wet fire detector. This is difficult and the antistatic agent may flow out immediately. Therefore, in such a fire detector, the antistatic effect of the antistatic agent could not be obtained.

The present invention has been made in view of the above circumstances, and in the state in which a heat detecting semiconductor such as a thermistor is reliably protected by a protector, a larger amount of heat flow due to a fire is applied to the heat detecting semiconductor side. It is possible to capture, and also
An object of the present invention is to provide a heat sensor capable of preventing dust adsorption due to electrification.

[0018]

A heat detector according to claim 1 of the present invention is a heat detector for detecting heat, a heat detector main body provided with the heat detector protruding, and the heat detector. And a protector for protecting the surroundings of the heat detector, wherein the protector has a top portion which is arranged to face the heat sensor body with the heat sensing portion in between and a heat of the heat sensor body. A plurality of plate-shaped fins that are provided upright around the sensing unit in a radial pattern, and the top portion is formed in a tubular shape that opens toward the heat sensing unit side and the opposite side thereof, and The top part of the fin is formed so that the inner diameter and the outer diameter become smaller as it approaches the heat sensing part, and the upper end part of the fin is connected to the outer peripheral surface of the top part, and the height of the upper end part of the top part of the fin. In the part corresponding to the above, from the outer circumference of the top of the top of the above fin That the extended portion formed to spread in a square side is provided with a means for solving the above-described problem.

According to the above structure, the airflow coming from the side facing the heat sensor body toward the heat sensor body hits the cylindrical top. Then, the airflow that has passed through the cylindrical top is directed to the heat detector main body side, but at this time, since the inner diameter becomes smaller as the cylindrical top approaches the heat sensing part, The airflow passing through the inside of the tubular top is converged and blows out from the opening on the side of the heat sensing part of the top of the tubular shape, and most of the airflow passing through the inside of the top of the tubular form is collected on the side of the heat sensing part to generate heat. It is possible to hit the sensing unit.

Further, since the outer diameter of the apex is reduced toward the heat sensing portion, the outer peripheral surface of the apex is a slope approaching the inner side as it goes downward, and from the side of the heat detector. When the airflow at the height of the top of the airflow toward the heat sensor passes between the adjacent fins and hits the outer peripheral surface of the top, the airflow is inclined by the outer peripheral surface which is the slope of the top. Will be directed downwards.

In addition, it passes between the adjacent fins, and
The airflow passing between the top and the heat sensing portion is also directed obliquely downward due to the airflow directed to the top and directed downward as described above. Therefore, in the conventional case, the airflow that collides with the top and is bent outward or the airflow that passes between the top and the heat sensing portion is bent obliquely downward and is directed toward the heat sensing portion. Most of them will hit the heat detector.

Further, in the case where the airflow at the height of the top of the airflow from the side of the heat sensor hits the expansion part of the fin, at least the airflow hitting the expansion part is reached. A part is guided to the top side by the expansion part and hits the outer peripheral surface of the top part. Then, the airflow hitting the outer peripheral surface of the top portion is directed obliquely downward as described above.

Therefore, the airflow that has conventionally passed over the hypotenuse of the fin hits the expanded portion of the fin and is directed toward the outer peripheral surface of the top, and hits the outer peripheral surface of the top toward the heat sensing portion. It will hit the heat detector. From the above, the air flow that did not hit the heat sensing unit in the past was taken into the heat sensing unit side and hits the heat sensing unit. The heat flow can be guided to the heat sensing portion side by the protector, and the sensitivity of the heat sensor can be improved.

The expanded portion needs to have a sufficient width in the vertical and lateral directions outside the outer periphery of the upper end of the top so as to block the passing airflow and direct it toward the top (the upper side of the top is higher than the upper end of the top). There is not always necessary). Further, even if only the extension part is provided on the fin, the airflow passing outside the outer circumference of the top part cannot be guided to the heat sensing part, and the extension part is provided on the fin and the outer peripheral surface of the top part is inclined as described above. The slope must be downward.

On the contrary, if only the outer peripheral surface of the top is formed as the above-mentioned slope, the airflow hitting the side surface of the top toward the center of the top is directed toward the heat sensor, but is displaced from the center of the top. The airflow hitting the side surface of the top is directed obliquely downward and outward and is not necessarily directed to the heat sensing portion side. However, when the above-mentioned extension is provided,
The expansion portion provided on the outer side of the top portion can direct at least a part of the airflow toward the outer side toward the center side of the top portion along the outer peripheral surface of the top portion.

In the heat detector according to the second aspect of the present invention, the protector and the main body of the heat detector are made of resin having an antistatic effect. According to the above structure, the same effect as that of claim 1 is obtained, and the resin itself forming the protector and the heat sensor main body does not have to be sprayed or coated with the antistatic agent on the surface of the protector and the heat sensor main body. Has an antistatic effect, so that it is possible to prevent the adsorption of dust and prevent the protector and the heat detector main body from becoming dirty.

Further, in the case of a resin having an antistatic effect, even if the surface is wet with water or the surface is rubbed, the effect of preventing a power failure is significantly reduced, unlike when a film of an antistatic agent is formed. The antistatic effect is retained for a long period of time. Therefore, it is not necessary to wipe and clean the protector and the heat sensor main body, and it is not necessary to frequently form a film of the antistatic agent on the surface of the protector and the heat sensor main body, and the maintenance of the heat sensor can be saved. it can. The resin having an antistatic effect basically has a low surface specific resistance, and includes a resin whose surface specific resistance is lowered by, for example, kneading an antistatic agent into the resin.

The heat sensor according to claim 3 of the present invention protects the heat sensing part for sensing heat, the heat sensor body provided with the heat sensing part protruding, and the periphery of the heat sensing part. A protector is provided, and the protector and the heat sensor main body are made of resin having an antistatic effect as a means for solving the above problems. According to the above configuration,
Similar to the configuration of the second aspect, it is possible to prevent the protector and the heat sensor main body from being contaminated, so that maintenance of the heat sensor can be saved.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION A heat sensor according to an example of an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a heat sensor B of this example, and FIG. 2, FIG. 3, and FIG.
Shows the relationship between the protector 10 of the heat detector B and the heat flow due to a fire. In addition, in these drawings,
Basically, the side attached to the ceiling surface is shown downward. That is, in these drawings, the heat sensor B
However, although it is shown upside down from the actual arrangement, the description will be made below with the top and bottom reversed.

As shown in FIG. 1, the heat sensor B of this example is shown.
Surrounds the thermistor 2 and a thermistor body 1 having a built-in circuit for heat sensing, a thermistor (heat sensing part) 2 provided in a state of extending upward from the central portion of the heat sensor body 1. And the protector 10 arranged as described above. The part of the heat sensor B excluding the protector 10 has basically the same configuration as the conventional heat sensor A, and the description thereof will be omitted. The protector 10
Has a top portion 11 that protects the upper surface side of the thermistor 2 and fins 12 that protect the outer peripheral side of the thermistor 2.
As shown in FIGS. 1 to 4, the top portion 11 has an outer shape in which an upper portion of a cone is cut off and turned upside down. In addition, the top portion 11 has a mortar shape inside, and has an upper surface and a lower surface opened.

That is, the top portion 11 has a cylindrical shape whose outer diameter and inner diameter become smaller from the upper portion toward the lower portion, and as shown in FIG.
1a and the inner peripheral surface 11b are tapered surfaces from the outer side to the inner side from the upper side to the lower side. Also, the top 11
Are arranged above the thermistor 2 and are arranged so that the thermistor 2 is located at the center of the opening on the lower surface of the top 11. That is, the top portion 11 is arranged above the thermistor 2 with the thermistor 2 in the center.

Therefore, when an air flow from the upper part of the top 11 to the lower part comes, the air flow is collected inside along the inner peripheral surface 11b of the top 11 so as to pass downward through the opening of the lower surface of the top 11. It has become. And top 1 as described above
Since the thermistor 2 is arranged just below the opening on the lower surface of 1, the airflow collected as described above hits the thermistor 2.

Further, the air flow hitting the outer peripheral surface 11a of the top 11 from the side of the top 11 is directed downward along the outer peripheral surface 11a, at least a part of which is a tapered surface, and is directed downward. The airflow hits the thermistor 2 arranged below the top 11. Similar to the fins of the conventional protector, the fins 12 are arranged radially around the thermistor 2 and spaced from the thermistor 2. In this example, six fins 12 ... Are arranged, but the number of fins 12 ... is not limited to this.
It is sufficient that the fins 12 ... Are arranged at appropriate intervals that can prevent the invasion of fingers and instruments.

Each of the fins 12 is formed in a substantially trapezoidal shape when viewed from the side, and the bottom side thereof is the bottom portion 1 of the protector 10.
3 and is further connected to the heat detector body 1 via the bottom portion 13. Also fin 1
The upper sides of 2 ... Have a height substantially equal to the height of the upper end of the top portion 11, and are horizontally extended outward from the outer edge portion of the upper end of the top portion 11.

The outer sides of the fins 12 ... Are slanted sides that extend outward from the outer ends of the upper sides. As described above, the fins 12 ... Have a state in which the upper side of the fins 12 horizontally extends outward from the outer edge portion of the top of the top 11, so that the tops of the fins 12 ... It is in a state of being expanded outward from the outer edge of. Then, in the upper end portions of the fins 12, ..., The portion that is expanded outward from the outer edge of the upper end of the top portion 11 is the expanded portion 12a.
That is, the fins 12 ... In this example have their upper ends expanded outward from the conventional fins.

The sides of the fins 12 on the side of the thermistor 2 are made substantially vertical, and the sides and the outer surface of the upper end of the top 11 are substantially aligned with each other. Then, the upper ends of the fins 12 ... And the upper ends of the tops 11 are joined to each other on the side of the fins 12 ... On the thermistor 2 side.

Further, on the side of the fins 12 on the thermistor 2 side, the support pieces 12b extending toward the tapered outer peripheral surface 11a inward from the upper end of the top 11 are integrally formed with the fins 12 ... It is provided. The side of the fins 12 on the thermistor 2 side and the upper end of the top portion 11 are integrally joined, and the fins 12 support pieces 12b.
, And the outer peripheral surface 11a below the upper end of the top portion 11 are joined, and the top portion 11 is supported by the fins 12.

Further, when a heat flow due to a fire strikes the expanded portions 12a ... And the support sides 12b provided at the portions corresponding to the height of the tops 11 of the fins 12 ... Are directed toward the center of the heat detector B along the fins 12 and hit the outer peripheral surface 11 a of the top 11. Then, the outer peripheral surface 11a of the top portion 11
As described above, the airflow that hits the lower part travels downward along the outer peripheral surface 11a, at least a part of which is a tapered surface. It is supposed to hit 2.

The protector 10 and the heat detector body 1 are made of composite resin having an antistatic effect. The resin having the antistatic effect is, for example,
The surface resistivity of the resin is lowered by mixing an antistatic agent into the resin, and it is less likely to be charged than general synthetic resins and can be discharged immediately after being charged.

Further, a resin having an antistatic effect is unlike the one in which an antistatic agent is simply applied to the surface of a synthetic resin, so that the antistatic performance does not greatly deteriorate due to wiping or getting wet with water. Therefore, the antistatic effect continues. Therefore, when the protector 10 and the heat detector main body 1 are made of the above resin, the antistatic effect is maintained without frequently spraying or applying the antistatic agent, so that the dust adsorption is performed for a long time. It is possible to prevent the heat sensor B from becoming dark.

In this example, the protector 10 and the heat sensor main body 1 were formed by using a multi-type thermoplastic resin mainly composed of polycarbonate, Multilon TN-3616Q (manufactured by Teijin Kasei Co., Ltd.). This resin can maintain antistatic performance for a long time,
In addition to having flame retardancy, it also has excellent impact characteristics, heat resistance, dimensional stability as a synthetic resin, and excellent moldability, so it can be suitably used for the heat sensor B. .

Next, the operation of the heat sensor B will be described. First, as shown in FIG. 2, a case where a heat flow due to a fire blows from above the heat detector will be described. A part of the hot air flow coming from above toward the heat detector B hits the top 11.

The top 11 on which the air flow hits is formed in a cylindrical shape having a large inner diameter on the upper surface side and a small inner diameter on the lower surface side, and its inner peripheral surface 11b is a mortar-shaped tapered surface. Most of the airflow that hits the top 11 hits the inner peripheral surface 11b. Further, most of the airflow hitting the inner peripheral surface 11b is along the inner peripheral surface 11b.
In the state of being collected on the center side of the above, it flows downward from the opening on the lower surface of the top portion 11.

The thermistor 2 is disposed below the center of the top 11, that is, below the opening on the lower surface of the top 11, and most of the airflow hitting the top 11 from above is inside the top 11. It will be guided to the thermistor 2 by being guided by the peripheral surface. In addition, not only when the airflow comes obliquely from above as shown in FIG. 2 but also when the airflow comes from directly above, the airflow is similarly distributed along the inner peripheral surface 11b of the top 11 toward the center of the top 11. As it is collected, it will flow under the top 11.

Therefore, from the upper side of the top 11, the heat sensor B
Since most of the airflow coming to the thermistor 2 can be applied to the thermistor 2, even if the top 11 protects the upper surface of the thermistor 2, it does not hinder the thermistor 2 from being hit by a hot airflow due to a fire, and conversely, It is possible to guide and take in the airflow that may pass around the thermistor 2 to the thermistor 2 side. That is,
It is possible to increase the sensitivity of the thermistor 2 by guiding the hot air flow to the thermistor 2 side without blocking the hot air flow by the top portion 11 of the protector 10 and hindering the detection of heat by the thermistor 2.

Next, a case where a heat flow due to a fire comes from the side of the heat detector B toward the heat detector B will be described. As shown in FIG. 3, of the airflows coming from the side toward the heat detector B, the airflows passing between the adjacent fins 12, 12 are generated by the fins 12 arranged radially. You will be guided from the center. Further, of these airflows, the airflow flowing on the upper side of the heat detector B hits the outer peripheral surface 11a of the apex 11, so that the airflow is slanted by the outer peripheral surface 11a which is a taper surface which is directed obliquely downward as described above. It will be directed downward. Further, the airflow flowing immediately below the airflow directed obliquely downward is also affected by the airflow directed obliquely downward and is directed obliquely downward.

Therefore, the airflow that strikes the apex 11 and the airflow that flows between the apex 11 and the thermistor 2 immediately below the apex 11 are directed obliquely downward to strike the thermistor 2. That is, in the conventional case, the airflow that hits the top 11 toward the outside of the heat sensor B and the airflow that passes between the top 11 and the thermistor 2 are caused by the outer peripheral surface 11 a of the top 11 as described above. Will be guided to the side and hit the thermistor 2,
The sensitivity of can be improved.

Next, of the heat flow from the side of the heat detector B toward the heat detector B due to the fire, the heat flow near the height of the top 11 will be described. FIG. 4 shows by arrows the airflows coming toward the heat detector B near the height of the top 11. Of the above-mentioned airflows, the airflow toward the central portion of the top 11 hits the outer peripheral surface 11a of the top 11 as described above and is guided obliquely downward to hit the thermistor 2.

Further, the airflow flowing slightly outside the central portion of the top 11 hits the above-mentioned expanded portions 12a, 12a of the two adjacent fins 12, 12 and is guided to the central portion of the top 11. The hot air flow guided to the central portion side hits the outer peripheral surface 11a of the top portion 11 and is guided obliquely downward to hit the thermistor 2. Further, further outward, that is, two adjacent fins 12, 12
The airflow flowing outside the
At least a part of the fins 12, 12 disposed on the left and right outside of the fins 12, 12 on the extended portions 12a, 12a is guided to the top portion 11 side and hits the outer peripheral surface 11a of the top portion 11 to be guided obliquely downward. Then, as in the case described above, the airflow strikes the thermistor 2.

Therefore, in the prior art, a part of the airflow that hits the top portion 11 and is guided to the outer side of the heat sensor B or passed above the fins 12 and 12 is partially finned.
Since the expanded portions 12a and 12a of FIG. 2 can guide the air to the top 11 side and the outer peripheral surface 11a of the top 11 can guide the air to the thermistor 2 side, more airflow can be taken in to the thermistor 2 side than in the conventional case. Therefore, the sensitivity of the thermistor 2 can be improved by taking in a large amount of hot air flow.

As described above, the top portion 11 has a cylindrical shape whose outer diameter and inner diameter decrease from the upper surface side toward the lower surface side, and the fins 12 ... By providing the expanded portions 12a ..., It is possible to take in a larger amount of heat flow to the thermistor 2 side than in the conventional case, and the protector 10 cuts off a part of the heat flow toward the thermistor 2 to prevent thermistor 2.
It is possible to prevent the sensitivity of the thermistor 2 from decreasing, and it is possible to increase the sensitivity of the thermistor 2 by positively introducing the hot air flow into the thermistor 2 side.

Further, as described above, the protector 10 and the heat sensor body 1 are made of a composite resin having an antistatic effect, so that the heat sensor B is prevented from being charged and dust is adsorbed to the heat sensor B. Can be prevented. Also, the heat sensor B
By preventing dust from adsorbing on the heat detector B
Can be prevented from becoming dirty and the laborious cleaning work of the heat sensor B can be eliminated, or the cleaning work can be reduced. Therefore, the maintenance of the heat detector B can be greatly saved.

The shape of the fins 12 ... Of the present invention is not limited to the trapezoidal shape described above, and the expanded portion 12 extending outward from the top 11 at a portion corresponding to the height of the top 11.
It suffices to have a structure in which a, a finger or the like is hard to enter on the thermistor 2 side while having a. Also, protector 1
0 and the material of the heat sensor body 1 are the above-mentioned Multilon TN-
The material is not limited to 3616Q, and other materials may be used.

However, in order to prevent the heat sensor B from being contaminated as described above, it is preferable that the protector 10 and the heat sensor main body 1 are made of resin having an antistatic effect. Further, the heat sensing unit is not limited to the thermistor 2 and may be any unit that has a changeable electrical characteristic with respect to temperature and can sense a change in temperature.

[0055]

According to the heat sensor of the first aspect of the present invention, the inner diameter becomes smaller as it approaches the heat sensing portion of the air flow coming from the side facing the heat sensor body toward the heat sensor body. The airflow that has passed through the smaller cylindrical top heads toward the heat sensing unit while being collected on the center side of the cylindrical top, collecting the heat flow generated by the fire on the heat sensing unit side. It is possible to hit the sensing unit.

Further, since the outer diameter of the top portion is reduced toward the heat sensing portion, the outer peripheral surface of the top portion is an inclined surface toward the center side toward the heat sensing portion. If the airflow at the height of the top of the airflow from the side to the heat sensor passes between the adjacent fins and hits the outer peripheral surface of the top, the airflow becomes the slope of the top. The surface is directed toward the heat sensing unit.

Also, passing between the adjacent fins, and
The airflow passing between the top portion and the heat sensing portion is also directed toward the heat sensing portion side by being influenced by the airflow that strikes the top portion and is directed to the heat sensing portion side as described above. Therefore, in the conventional case, the airflow that collides with the top and is bent outward or the airflow that passes between the top and the heat sensing portion is directed toward the heat sensing portion and hits the heat sensing portion.

Further, in the case where the airflow of the height of the top of the airflow from the side of the heat sensor hits the expansion part of the fin, at least the airflow hitting the expansion part is reached. A part is guided to the top side by the expansion part and hits the outer peripheral surface of the top part. Then, the airflow hitting the outer peripheral surface of the top is directed to the heat sensing unit side as described above.

Therefore, the airflow that has conventionally passed over the hypotenuse of the fins is directed toward the outer peripheral surface of the top by hitting the expanded portion of the fin, and is directed toward the heat sensing portion by contacting the outer peripheral surface of the top. It will hit the heat detector. From the above, the airflow that did not hit the heat sensor in the past was taken into the heat sensing part and hits the heat sensing part. The heat flow can be guided to the heat sensing portion side by the protector, and the sensitivity of the heat sensor can be improved.

According to the heat sensor of claim 2 of the present invention, it is possible to obtain the same excellent effect as that of the structure of claim 1, and the resin itself constituting the protector and the heat sensor main body is Since it has an antistatic effect, the antistatic effect does not decay in a short period of time,
It is possible to prevent the adsorption of dust for a long period of time and prevent the protector and the heat detector main body from becoming dirty. Therefore, it is not necessary to wipe and protect the protector and the heat sensor main body or to frequently form a film of the antistatic agent on the surface of the protector and the heat sensor main body. it can.

According to the heat sensor of the third aspect of the present invention, as in the case of the structure of the second aspect, it is possible to prevent the heat sensor from being contaminated, so that maintenance of the heat sensor can be saved. Can be converted.

[Brief description of drawings]

FIG. 1 is a side view showing a heat sensor according to an example of an embodiment of the present invention.

FIG. 2 is a schematic side view in which a part of the protector for explaining the relationship between the protector of the heat sensor of the above example and the air flow is omitted.

FIG. 3 is a schematic side view in which a part of the protector for explaining the relationship between the protector and the air flow of the heat sensor of the above example is omitted.

FIG. 4 is a schematic plan view of the protector for explaining the relationship between the protector of the heat sensor of the above example and the air flow.

FIG. 5 is a side view showing a conventional heat sensor.

FIG. 6 is a schematic side view in which a part of the protector for explaining the relationship between the protector of the conventional heat detector and the air flow is omitted.

FIG. 7 is a schematic side view in which a part of the protector for explaining the relationship between the protector of the conventional heat detector and the air flow is omitted.

FIG. 8 is a schematic plan view of a protector for explaining the relationship between the protector of the conventional heat detector and the air flow.

[Explanation of reference numerals] 1 heat detector main body 2 thermistor (heat sensing unit) 10 protector 11 top 12 fins 12a extension

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuyoshi Sakurai 1-11-6 Hatagaya, Shibuya-ku, Tokyo Nittan Co., Ltd. (72) Inventor Tomoyuki Yamamoto 1-1-11 Hatagaya, Shibuya-ku, Tokyo Nittan Electronic Co., Ltd. (72) Inventor Nobuo Nagata 1 Minamihata, Konoike, Itami City, Hyogo Nittan Seiki Co., Ltd. (72) Toshiyuki Ikeda 1 Minamihata, Konoike, Itami City, Hyogo Nittan Seiki Co., Ltd.

Claims (3)

[Claims] 1. A heat sensor comprising: a heat sensing part for sensing heat; a heat sensor body provided with the heat sensing part protruding; and a protector for protecting the periphery of the heat sensing part. The protector has a top portion arranged to face the heat detector body with the heat sensing portion in between, and a plurality of plate-like members that are erected radially around the heat sensing portion of the heat sensor body. A fin, and the top portion is formed in a tubular shape that opens toward the heat sensing portion side and the opposite side thereof, and the inner diameter and the outer diameter are increased as the tubular top portion approaches the heat sensing portion. The fin is formed to be small, and the upper end portion of the fin is connected to the outer peripheral surface of the top portion, and the fin is provided at a portion corresponding to the height of the upper end of the top portion of the fin from the outer periphery of the upper end of the top portion. There is an expansion part that is formed by expanding to the outside A heat sensor characterized in that. 2. The heat sensor according to claim 1, wherein the protector and the heat sensor body are made of resin having an antistatic effect. 3. A heat sensor comprising: a heat sensing part for sensing heat; a heat sensor body provided with the heat sensing part protruding; and a protector for protecting the periphery of the heat sensing part. A heat sensor, wherein the protector and the heat sensor body are made of resin having an antistatic effect.