JP2000067340A - Smoke sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain accurate smoke detection over a long period by providing a smoke sensor with a dust-proofing means for preventing the pile of dust on a smoke inflow port through which smoke flows into a smoke sensing area. SOLUTION: In the smoke sensor 1, a cylindrical smoke sensing part S of which diameter is smaller than that of a cylindrical body B is formed on the body B. The smoke sensing part S has a smoke sensing area inside and a smoke inflow port H is formed on the outer periphery of the side face of the sensing part S. Thereby smoke generated due to a fire or the like is allowed to flow into the smoke sensing area through the inflow port H formed over the whole outer periphery of the side face of the sensing part S. A dust-proofing means G is projected from the body B of the sensor 1, and when the sensor 1 is attached to a wall surface or the like, the means G covers the upper part of the inflow port H. Although the projected length L of the means G is not restricted, it is preferable to secure a length capable of hiding the sensing part S at the time of observing it from the upper part of the sensor 1. Similarly, the width W of the means G is preferably secured so as to hide the smoke sensing part S at the time of observing it from the upper part of the sensor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a smoke detector mounted on a wall or the like.

[0002]

2. Description of the Related Art Conventionally, in this type of smoke detector, a smoke sensing area is provided inside, and light receiving element receives light scattered light from a light emitting element due to smoke flowing into the smoke sensing area, When the light receiving output becomes equal to or higher than the value indicating the predetermined smoke density, a notification signal is issued.

As shown in FIG. 3, a smoke detector 1 has a body B installed on a ceiling or the like, and a smoke sensing section S provided below the body B. That is, the smoke detector 1 has a cylindrical body B
A cylindrical smoke sensing section S including a smoke sensing area below the
A smoke inlet H for guiding smoke to the smoke sensing area is provided on the outer periphery of the side surface of the smoke sensing section S. The smoke detector 1 is designed to allow smoke to flow in but not light. Within the smoke detector 1, there is provided a light projecting section composed of a light emitting element such as a light emitting diode, and a light receiving section composed of a light receiving element such as a photodiode provided with a light receiving axis shifted from the optical axis of the light projecting element. Thus, a smoke sensing area for sensing smoke is formed near the intersection of the light projecting axis and the light receiving axis. An insect net is provided on the outer periphery of the smoke inlet H to prevent insects and dust from flowing in.

In the smoke detector 1 as described above, when the smoke flows into the smoke sensing area, the light emitted from the light emitting element is irregularly reflected on the smoke, and the scattered light is received by the light receiving element. Smoke is detected.

[0005]

However, when the smoke detector 1 having the above-mentioned structure is mounted on a wall or the like and used for a long time, dust or the like accumulates on the upper portion of the smoke inlet H, and the dust causes the dust to accumulate. 1 has a problem that the inflow of smoke into the interior of the vehicle 1 is reduced.

[0006] The present invention has been made in view of the above problems, and an object of the present invention is to prevent a decrease in the inflow of smoke even when it is attached to a wall or the like.
An object of the present invention is to provide a smoke detector capable of performing accurate smoke detection for a long period of time.

[0007]

According to the first aspect of the present invention,
In the smoke detector that emits an alarm when the smoke density in the smoke sensing area becomes equal to or higher than a predetermined value, dust prevention means is provided to prevent dust from being deposited on a smoke inlet through which smoke flows into the smoke sensing area. It is characterized by the following.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIGS. FIG. 1 is an external view of a smoke detector according to the present invention, in which (a) shows a side view and (b) shows a front view. FIG. 2 is an explanatory diagram showing the inside of the smoke detector.

As shown in FIG. 1, the smoke detector 1 is provided with a cylindrical smoke sensing portion S having a smaller diameter than the body B on a cylindrical body B. The smoke sensing portion S has a smoke sensing region A described later therein, and a smoke inlet H is provided on the outer periphery of the side surface of the smoke sensing portion S. Therefore, smoke generated by a fire or the like flows into the smoke sensing area A via the smoke inlet H provided on the entire outer periphery of the side surface of the smoke sensing section S.

The body B of the smoke detector 1 is provided with a dustproof eave (dustproof means) G. The dustproof eave G covers the upper part of the smoke inlet H when the smoke detector 1 is mounted on a wall or the like. It has become. There is no limitation on the amount of protrusion L of the dustproof eaves G, but it is desirable to secure a length such that the smoke sensing portion S is hidden from above the smoke detector 1 as shown in FIG. Similarly, the width W of the dustproof eave G is equal to the smoke detector 1
It is desirable to secure a width such that the smoke sensing portion S is hidden when viewed from above.

As shown in FIG. 2, a light projecting unit 2 and a light receiving unit 3 are formed inside a smoke detector 1. The light projecting section 2 includes a light projecting element 4, and the light receiving section 3 includes a light receiving element 5. The light projecting element 4 and the light receiving element 5 are arranged such that their optical axes 40 and 50 are shifted from each other.

Optical axes 40 and 50 of light projecting element 4 and light receiving element 5
The vicinity of the intersection 6 forms a smoke sensing area A. Further, the light blocking member 7 prevents light from the light projecting element 4 from directly entering the light receiving element 5.

A labyrinth 9 having a substantially rectangular shape is formed at predetermined intervals around the wall of the smoke sensing area A. The labyrinth 9 allows smoke to flow into the smoke sensing area A but not external light.

The light projecting section 2 having the light projecting element 4 has openings 11 and 12 on the light emitting surface side of the light projecting element 4 so that light from the light projecting element 4 directly enters the light receiving element 5. Preventing.

In the smoke detector 1 having the above-described configuration, when the smoke detector 1 is installed on a wall or the like, a large amount of dust or the like that easily accumulates above the smoke inlet H is deposited on the dustproof eaves G. This makes it possible to reduce the amount of dust that may block the upper part of the smoke inlet H. With the dustproof eaves G, it is possible to prevent a problem that smoke does not flow into the smoke-sensing area A due to dust or the like deposited on the smoke inflow port H, even though a large amount of smoke is generated due to a fire or the like. become. Therefore, according to the smoke detector 1 of the present embodiment, it is possible to reduce the occurrence of a large difference between the density of the generated smoke and the density of the smoke in the smoke-sensitive area due to dust or the like deposited on the smoke inlet H. It is possible to prevent an erroneous operation such as not emitting an alarm even if the smoke reaches the notification density for a long time.

If the dustproof eaves G are detachable, the unnecessary dustproof eaves G are removed when the smoke detector 1 is installed on a ceiling or the like, and the dustproof eaves G are removed only when the smoke detector 1 is installed on a wall or the like. The eaves G can be attached, and the smoke detector 1 can be used both for wall installation and ceiling installation.

[0017]

As described above, according to the first aspect of the present invention, in the smoke detector that issues an alarm when the smoke density in the smoke sensing area exceeds a predetermined value, the smoke flows into the smoke sensing area. Dust prevention means is provided to prevent the accumulation of dust on the smoke inlet, so that when the smoke detector is mounted on a wall or the like, the dust or the like deposited on the smoke inlet is removed by the dust prevention means G. Since it is possible to reduce the amount of smoke, it is possible to provide a smoke detector that can accurately detect smoke over a long period of time by preventing a decrease in the inflow of smoke even when the smoke detector is mounted on a wall or the like. To play.

[Brief description of the drawings]

FIG. 1 is an external view of a smoke detector according to the present invention, wherein FIG.
Shows a side view, and (b) shows a front view.

FIG. 2 is an explanatory diagram showing the inside of a smoke detector.

FIG. 3 is an external perspective view of a conventional smoke detector installed on a ceiling surface or the like.

[Explanation of symbols]

 1 Smoke detector A Smoke sensing area G Dust prevention means H Smoke inlet

Continued on the front page (72) Inventor Shigeki Shimomura 1048 Odomo Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd. F-term (reference) 5C085 AA03 BA33 CA30 FA11 FA16

Claims (1)

[Claims] 1. A smoke detector for issuing an alarm when the smoke density in a smoke sensing area exceeds a predetermined value, wherein dust is prevented from being deposited on a smoke inlet through which smoke flows into the smoke sensing area. A smoke detector characterized in that a smoke detector is provided.