EP1146492B1

EP1146492B1 - Multi-sensor

Info

Publication number: EP1146492B1
Application number: EP01302017A
Authority: EP
Inventors: Kazuyoshi c/o Nittan Company Limited Sakurai; Ichiro c/o Nittan Company Limited Hamada; Yasunori c/o Nittan Company Limited Oya
Original assignee: Nittan Co Ltd
Current assignee: Nittan Co Ltd
Priority date: 2000-03-17
Filing date: 2001-03-06
Publication date: 2003-05-07
Anticipated expiration: 2021-03-06
Also published as: JP3902377B2; JP2001266265A; EP1146492A3; EP1146492A2; CN1314664A; CN1145126C

Description

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a multi-sensor for sensing (detecting) a fire by smoke and heat.

Description of the Related Art

A multi-sensor which senses heat by using a heat sensing element, such as a thermistor or the like, and which senses smoke by detecting a scattered light with a light detecting element, which is generated by scattering a light emitted from a light emitting element, has been known before.
In such a mufti-sensor, because the heat sensing element sensitively detects an ascending air current caused by a fire, it is necessary to dispose the heat sensing element on a top portion of the multi-sensor (that is, dispose it on a lower side of the multi-sensor when the multi-sensor is attached to a ceiling). On the other hand, because a circuit board for processing signals in the sensor is provided on a lower portion of the sensor (that is, on an upper side of the sensor when the sensor is attached to a ceiling), it is necessary to provide a wire for connecting the heat sensing element with the circuit board.
A smoke sensing area in which an optical axis of the light emitting element and that of the light detecting element cross, is formed between the top portion of the sensor and the circuit board. Therefore, the wire for connecting the heat sensing element with the circuit board, is arranged so as to avoid the smoke sensing area. For example, in Japanese Patent Application Publication No. Tokukai-Hei 4-268697, it is described that a through hole is formed in a labyrinth portion provided around the smoke sensing area to pass the wire through the through hole.
However, in such a wiring structure, it takes a lot of time to assemble the multi-sensor when the sensor is manufactured, and to detach or assemble the sensor when the maintenance of the sensor is carried out after the attachment thereof. Although the method for providing the wire outside the sensor is suggested, the method is not suitable by the above reason.
In Japanese Patent Application Publications No. Tokukai-Hei 10-40476 and No. Tokukai-Hei 11-185179, multi-sensors in which a wire passes through the inside of the the smoke sensing area are disclosed.
However, when the wire passes through the inside of the sensor, a reflected light generated on the surface of the wire is detected by the light detecting element as a noise light. Therefore, a sensibility for detecting smoke deteriorates. In particular, the surface forms of the wires made by covering a metal wire with soft resin are slightly different multi-sensor by multi-sensor. Because the amounts of generated noise light were different by wire, there was a problem that the variation of the detection sensibility occurs multi-sensor by multi-sensor.
Further, in case that the wire was arranged so as to avoid the smoke sensing area like the above publications, there was a problem that a sensibility for detecting heat was biassed to a specific tendency.

SUMMARY OF THE INVENTION

In order to solve the above-described problems, an object of the present invention is to provide a multi-sensor which is easily assembled when the sensor is manufactured, and which is easily detached or assembled when the maintenance of the sensor is carried out after the attachment of the sensor, and in which a wire can be arranged so as to hardly influence the detection sensibility or the tendency thereof.
That is, in accordance with one aspect of the present invention, a multi-sensor comprises:
a smoke chamber for sensing smoke by detecting a scattered light with a light detecting portion, the scattered light being generated by the smoke which enters the smoke chamber to scatter a light emitted from a light emitting portion
a heat sensing element for sensing heat, which is provided above the smoke chamber; and
an insert portion which constitutes a wall body having a hole for inserting a wire of the heat sensing element;
According to the present invention, because the wire of the heat sensing element passes through the insert portion which constitutes a wall body having a hole for inserting the wire of the heat sensing element wherein the wall body is approximately consecutive from the upper surface of the inside of the smoke chamber to the lower surface of the inside of the smoke chamber, and the hole penetrates through the upper surface to the lower surface, to the external portion of the smoke chamber, the wire can pass through the inside of the smoke chamber in a state of covering the wire with the insert portion.
As a result, when the multi-sensor is assembled, the wiring of the heat sensing element is carried out by only passing the wire through the insert portion. The insert portion acts as a guide for attaching the heat sensing element and setting the position of the heat sensing element. Therefore, it can be easy that the multi-sensor is assembled when the multi-sensor is manufactured, and that the multi-sensor is detached or assembled when the maintenance of the multi-sensor is carried out.
Because the wire is not bare in the smoke chamber, a noise light is not generated from the surface of the wire. Therefore, the amounts of generated noise light are not different multi-sensor by multi-sensor. The performance for the fire detection becomes stable multi-sensor by multi-sensor.
When the insert portion is made from, for example, hard resin, the variation of the surface forms of the insert portion is small. Even though a light reflects on the surface of the insert portion and the reflected light becomes a noise light, the problem that the performance for the fire detection is different multi-sensor by multi-sensor, is not caused.
In the specification, the term "above the smoke chamber" means the top portion side of the smoke chamber, that is, the lower side of the multi-sensor which is attached to a ceiling.
The term "the wall body which is approximately consecutive from the upper surface of the inside of the smoke chamber to the lower surface of the inside of the smoke chamber" does not necessarily mean that the wall body is perfectly consecutive from the upper surface of the inside of the smoke chamber to the lower surface of the inside of the smoke chamber. The wall body may have the continuity that the wire is not bare in the smoke chamber and that a noise light is not generated.
A light shielding plate for shielding the light detecting portion from directly detecting a light emitted by the light emitting portion, may be provided in the smoke chamber, and the insert portion may use at least a part of the light shielding plate.
Because the insert portion for passing the wire of the heat sensing element uses at least a part of the light shielding plate, the insert portion is provided near the central portion of the smoke chamber. Therefore, the sensibility of the heat sensing element is not biased to a specific tendency. It is possible to detect a fire in all directions at the same sensibility.
The term "the insert portion uses at least a part of the light shielding plate" may include the situation that a part of light shielding plate is used as a wall body and acts as the insert portion.
The light shielding plate may be formed in a cylindrical shape, and acts as the insert portion.
Because the multi-sensor uses a light shielding plate provided in a sensor according to an earlier development, the number of parts does not increase.
The multi-sensor may further comprise:
a fixing member for fixing the light detecting portion and the light emitting portion; and
a casing having a structure which prevents a light from entering the smoke chamber from a side surface of the casing, one of an upper surface of the casing and a lower surface of the casing being open;

Because the insert portion is united with the fixing member, the multi-sensor is more easily assembled. Further, because the space between the insert portion and the fixing member does not exist, an outer light hardly enters the smoke chamber.
The multi-sensor may further comprise:
a fixing member for fixing the light detecting portion and the light emitting portion; and
a casing having a structure which prevents a light from entering the smoke chamber from a side surface of the casing, one of an upper surface of the casing and a lower surface of the casing being open;

Because the insert portion is united with one surface of the casing, the multi-sensor is more easily assembled. Further, because the space between the insert portion and the casing does not exist, an outer light hardly enters the smoke chamber.
As a "structure which prevents a light from entering the smoke chamber", there is a known labyrinth structure or the like. However, any structure may be used if the structure can prevent a light from entering the smoke chamber.
The scope of the invention is defined by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood form the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not intended as a definition of the limits of the present invention, and wherein;
Fig. 1 is an exploded perspective view showing a sensor as an example of the multi-sensor according to the present invention;
FIG. 2 is a vertical sectional view showing a state that each member shown in FIG. 1 is incorporated into the sensor; and
FIG. 3 is a horizontal sectional view for showing the inside of the labyrinth body.

PREFERRED EMBODIMENT OF THE INVENTION

Hereinafter, an embodiment of the present invention will be explained in detail with reference to FIGS. 1 to 3.
FIG. 1 shows each member for constructing a sensor 1 as an example of the multi-sensor according to the present invention. FIG. 2 is a vertical sectional view showing a state that each member shown in FIG. 1 is incorporated into the sensor.
In FIGS. 1 and 2, the reference numeral 2 denotes a cover portion, 3 denotes a main body case, 4 denotes a labyrinth body, 5 denotes an insect mesh, 6 denotes a shield case, 7 denotes an optical element portion, 8 denotes a circuit board, 9 denotes a base and 10 denotes a thermistor. FIG. 3 is a horizontal sectional view for showing the inside of the labyrinth body 4.
The cover portion 2 is a cover for covering a top portion of the sensor 1. In the cover portion 2, air fins 2a, 2a ··· for introducing the air from the circumference of the sensor 1, are formed. Further, through holes 2b, 2b ··· for passing the air to the inside of the sensor 1 are provided between the air fins 2a and 2a which are next to each other. The thermistor 10 is provided in a space which is surrounded by the through holes 2b, 2b ··· as shown in FIG. 2. The space acts as a heat sensing area T. In the cover portion 2, as shown in FIG. 2, a contacting portion 2c for approximately contacting with the inside of the projecting portion 3b formed in the main body case 3, is formed in an annular shape. The cover portion 2 is fixed to the main body case 3 by fitting the contacting portion 2c in the circumference of the projecting portion 3b and by engaging a pawl which is not shown in the figure, with a predetermined portion of the main body case.
The main body case 3 is a casing for covering the labyrinth body 4 and the like. On the center of the main body case 3, an opening 3a is formed. A projecting portion 3b is provided so as to surround the opening 3a. In the main body case 3, inflow holes 3c, 3c ··· which are formed along a peripheral direction so as to flow smoke into the smoke chamber S, are provided.
As shown in FIG. 2, a plurality of engaging pawls 3f for fixing the main body case 3 to the base 9, are provided on the inner and lower portion of the main body case 3. In FIG. 2, only one engaging pawl is shown.
One surface of the labyrinth body (casing body) 4 is covered with a disk-shaped plate 4d. In the labyrinth body 4, a plurality of light shielding walls 4a having cross sections formed in a Z-shape, an M-shape and the like, a containing portion 4b for containing a light emitting portion 12 which will be explained below, and a containing portion 4c for containing a light detecting portion 13, are provided in each predetermined position. In the present embodiment, the containing portion 4b for the light emitting portion 12 and the containing portion 4c for the light detecting portion 13 are provided in the labyrinth body 4. However, when these are provided in the shield case 6, a shielding effect against the light emitting portion 12 and the light detecting portion 13 can be also obtained. An area which is surrounded by the light shielding walls 4a, 4a, ··· and the containing portions 4b and 4c in the labyrinth body 4, acts as a smoke chamber S.
On the center of the plate 4d, a lead hole 4e for inserting a lead wire 10a of the thermistor 10, is provided.
By the labyrinth body 4, outer smoke which is flowed from the inflow holes 3c, 3c, ··· of the main body case 3, is introduced into the smoke chamber S. On the other hand, outer light can be prevented from entering the smoke chamber S.
The circumference of the labyrinth body 4 is covered with the insect mesh (insect screen) 5 having a plurality of fine meshes. The insect mesh 5 prevents an insect or the like from entering the labyrinth body 4.
The shield case 6 is provided so as to cover the upper surface of the circuit board 8, as shown in FIG. 2. On the center of the shield case 6, a hole 6a for a support body, in which a support body 11 of the optical element portion 7 can be fit, is formed.
The shield case 6 is fixed to the base 9 by using a pawl which is not shown in the figure.
As shown in FIG. 3 (but not shown in FIG. 1), on the upper surface of the shield case 6, a circular regulation wall 6e and a plurality of regulation plates 6d, 6d, 6d and 6d which project from the regulation wall 6e, are provided in order to regulate the position in which the labyrinth body 4 is contained.
The optical element portion 7 comprises a support body (fixing member) 11 and a light emitting portion 12, a light detecting portion 13 and a light shielding plate 14 which are provided on the support body 11. The light emitting portion 12 comprises a light emitting element (not shown in the figure), and regularly emits a light under the control of the circuit board 8. On the other hand, the light detecting portion 13 comprises a light detecting element (not shown in the figure). and transmits a light detecting signal to the circuit board 8.
The light shielding plate 14 blocks a light which directly reaches from the light emitting portion 12 to the light detecting portion 13, so as not to directly detect a light emitted from the light emitting element of the light emitting portion 12 by the light detecting element of the light detecting portion 13. The light shielding plate 14 is made from hard resin and is united with the support body 11. The light shielding plate 14 has a height to approximately reach the lower surface of the plate 4d of the labyrinth body 4. The light shielding plate 14 is formed in a cylindrical shape as shown in FIGS. 2 and 3. The light shielding plate 14 comprises a through hole 14a for inserting the lead wire 10a, which penetrates the light shielding plate 14 in an upper and lower direction.
The optical element portion 7 is incorporated into the sensor 1 by soldering the light emitting element of the light emitting portion 12 and the light detecting element of the light detecting portion 13 which are provided on the support body 11, to the circuit board 8. The light emitting portion 12 is contained in the containing portion 4b of the labyrinth body 4. The light detecting portion 13 is contained in the containing portion 4c. The light shielding plate 14 is erected in an upper and lower direction in the smoke chamber S of the labyrinth body 4.
On the circuit board 8, a predetermined electronic circuit (not shown in the figure) for controlling the operation of the sensor 1, is formed. The light emitting element and the light detecting element are connected with the circuit board 8. The lead wire 10a of the thermistor 10 is connected with the center portion of the upper surface of the circuit board 8.
The circuit board 8 is fixed to the base 9 by screws 15 and 15 as shown in FIG. 2.
The base 9 is formed in a disk-shape as shown in FIG. 1. The base 9 constitutes a lower portion of the casing of the sensor 1. On the rear side of the base 9, an engaging portion for fixing the sensor to a ceiling by connecting the base with an attachment base (not shown in the figure) which is previously attached to the ceiling, is provided.
On the peripheral portion of the base 9, a plurality of notches 9a (in FIG. 2, only one notch is shown) are provided so as to correspond to the engaging pawls 3f of the main body part 3.
Each member having the above structure, is arranged as follows. As shown in FIG. 2, the circuit board 8, the optical element portion 7 and the shield case 6 are provided on the base 9. The labyrinth body 4 is mounted on the shield case 6 in a state the position of the labyrinth body 4 is adjusted so that the light emitting portion 12 projecting to the upper surface of the shield case 6 is contained in the containing portion 4b and the light detecting portion 13 is contained in the containing portion 4c. The main body case 3 is fixed to the base 9 by engaging a plurality of engaging pawls 3f of the main body case 3 with the corresponding notches 9a of the base 9. The cover portion 2 is fixed to the main body case 3. The lead wire 10a of the thermistor 10 connected with the circuit board 8, passes through the through hole 14a and the lead hole 4e of the labyrinth body 4. The sensor 1 is assembled so as to provide the thermistor 10 in the heat sensing area T of the cover portion 2.
The sensor 1 is attached to a ceiling in a state the cover portion 2 is directed downwardly. Heat caused by a fire is sensed by the thermistor 10 in the heat sensing area T. The light emitting portion 12 emits a light regularly. In a normal status, the emitted light is blocked by the light shielding plate 14 and is not detected by the light detecting portion 13. When smoke caused by a fire flows into the labyrinth body 4, the light emitted from the light emitting portion 12 is scattered. The scattered light is detected by the light detecting portion 13. Therefore, the fire is detected. As described above, the sensor 1 detects a fire by sensing both heat and smoke.
In the above sensor 1, the lead wire 10a of the thermistor 10 passes through the through hole 14a of the light shielding plate 14 united with the support body 11. Therefore, the lead wire 10a can pass through the inside of the smoke chamber S in a state that the lead wire 10a is covered with the light shielding plate 14.
As a result, when the sensor 1 is assembled, the operation for arranging the lead wire so as to avoid the smoke sensing area, can be simple because the lead wire 10a only passes through the through hole 14a. Further, the through hole 14a acts as a guide for attaching the thermistor 10 and setting the position of the thermistor 10. Therefore, it can be easy that the sensor is assembled when the sensor is manufactured, and that the sensor is detached or assembled when the maintenance of the sensor is carried out.
Because the lead wire 10a is not bare in the smoke chamber S, a noise light is not generated from the surface of the lead wire. Therefore, the amounts of generated noise light are not different multi-sensor by multi-sensor. The performance for the fire detection becomes stable multi-sensor by multi-sensor.
Because the light shielding plate 14 is made from hard resin, the variation of the surface forms of each light shielding plate is small. Even though a light reflects on the surface of the light shielding plate 14 and the reflected light becomes a noise light, the problem that the performance for the fire detection is different multi-sensor by multi-sensor, is not caused.
Because the through hole 14a is formed by using the light shielding plate 14, the lead wire 10a can pass through the approximately central portion of the smoke chamber S. Therefore, the sensibility of the thermistor 10 is not biased to a specific tendency. It is possible to detect a fire in all directions at the same sensibility. Because the sensor 1 uses a light shielding plate provided in a sensor according to an earlier development, the number of parts does not increase even though the through hole 14a is formed in the light shielding plate.
Because the light shielding plate 14 is united with the support body 11, the sensor 1 is more easily assembled. Further, because the space between the support body 11 and the light shielding plate 14 does not exist, an outer light does not enter the smoke chamber S.
The multi-sensor according to the present invention is not limited to the above embodiment. The concrete structure, the shape, or the like of each member can be suitably modified without departing from the gist of the present invention. For example, the light shielding plate may be united with the plate of the labyrinth body.
According to the present invention, because the wire of the heat sensing element passes through the insert portion constituting the wall body which is approximately consecutive from the upper surface of the inside of the smoke chamber to the lower surface of the inside of the smoke chamber, and which has the hole for inserting the wire of the heat sensing element, wherein the hole penetrates through the upper surface to the lower surface, to the outside of the smoke chamber, the wire can pass through the inside of the smoke chamber in a state of covering the wire with the insert portion.
As a result, when the multi-sensor is assembled, the wiring of the heat sensing element is carried out by only passing the wire through the insert portion. The insert portion acts as a guide for attaching the heat sensing element and setting the position of the heat sensing element. Therefore, it can be easy that the multi-sensor is assembled when the multi-sensor is manufactured, and that the multi-sensor is detached or assembled when the maintenance of the multi-sensor is carried out.
Because the wire is not bare in the smoke chamber, a noise light is not generated from the surface of the wire. Therefore, the amounts of generated noise light are not different multi-sensor by multi-sensor. The performance for the fire detection becomes stable multi-sensor by multi-sensor.
When the insert portion is made from, for example, hard resin, the variation of the surface forms of the insert portion is small. Even though a light reflects on the surface of the insert portion and the reflected light becomes a noise light, the problem that the performance for the fire detection is different multi-sensor by multi-sensor, is not caused.
Because the insert portion for passing the wire of the heat sensing element uses at least a part of the light shielding plate, the insert portion is provided near the central portion of the smoke chamber. Therefore, the sensibility of the heat sensing element is not biased to a specific tendency. It is possible to detect a fire in all directions at the same sensibility.
Because the multi-sensor uses a light shielding plate provided in a sensor according to an earlier development, the number of parts does not increase.
Because the insert portion is united with the fixing member, the multi-sensor is more easily assembled. Further, because the space between the insert portion and the fixing member does not exist, an outer light hardly enters the smoke chamber.
Because the insert portion is united with the casing, the multi-sensor is more easily assembled. Further, because the space between the insert portion and the casing does not exist, an outer light hardly enters the smoke chamber.

Claims

A multi-sensor comprising:

a smoke chamber (S) for sensing smoke by detecting a scattered light with a light detecting portion (13), the scattered light being generated by smoke which enters the smoke chamber to scatter a light emitted from a light emitting portion (12);

a heat sensing element (10) for sensing heat, which is provided above the smoke chamber (S); and

an insert portion (14) which constitutes a wall body defining a hole (14a) for receiving a wire (10a) of the heat sensing element (10);

wherein the wall body is substantially continuous from an upper inside surface of the smoke chamber (S) to a lower inside surface of the smoke chamber (S), and the hole (14a) extends through the upper surface and the lower surface, to a position outside of the smoke chamber (S).
The multi-sensor as claimed in Claim 1, wherein a light shielding plate for shielding the light detecting portion (13) from directly detecting a light emitted by the light emitting portion (12), is provided in the smoke chamber (S) and
the insert portion (14) comprises at least a part of the light shielding plate.
The multi-sensor as claimed in Claim 2, wherein the light shielding plate is formed in a cylindrical shape, and acts as the insert portion (14).
The multi-sensor as claimed in any one of Claims 1 to 3, further comprising:

a fixing member (11) for fixing the light detecting portion (13) and the light emitting portion (12); and

a casing (6) having a structure (4) which prevents a light from entering the smoke chamber from a side surface of the casing, one of an upper surface of the casing and a lower surface of the casing being open;

wherein the light emitting portion (12) and the light detecting portion (13) which are fixed to the fixing member (11), are provided in the casing (6) from the open surface of the casing, an inside of the casing acting as the smoke chamber (S); and
the wall body (14) forming the insert portion is united with the fixing member.
The multi-sensor as claimed in any one of Claims 1 to 3, further comprising:

a fixing member (11) for fixing the light detecting portion (13) and the light emitting portion (12); and

a casing (6) having a structure which prevents a light from entering the smoke chamber (S) from a side surface of the casing, one of an upper surface of the casing and a lower surface of the casing being open;

wherein the light emitting portion (12) and the light detecting portion (13) which are fixed to the fixing member (11), are provided in the casing from the open surface of the casing, an inside of the casing acting as the smoke chamber; and
the wall body (14) forming the insert portion is united with a surface of the casing, which is opposite to the open surface of the casing.