JPH0462119B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an alarm for a fire or theft prevention device, which is equipped with means for preventing contamination of the emitting and receiving parts.

[Prior art]

Conventionally, in a radiation type fire detector installed in a road tunnel, for example, as shown in FIG. A plate 22' was provided. Floating dust collides with and falls on this dust-proof plate 22', thereby preventing the light-receiving window 21' from getting dirty, thereby reducing the number of times of cleaning.

[Problems with conventional technology]

However, in the case where a plate-shaped dustproof plate 22' is provided,
When the airflow 3 crosses the dustproof plate 22', the downstream side becomes negative pressure and the airflow falls as shown by the arrow 31', so the main flow of air becomes a flow as shown by the arrow 32', and the dustproof plate 22' It is possible to prevent dust from adhering to the light receiving window 21' only up to a position slightly higher than the height of the light receiving window 21'. Therefore, in a detector having a wide field of view, the provision of a dustproof plate limits the field of view and sometimes reduces the functionality of the detector.

[Means for solving problems]

In view of the above-mentioned points, the present invention provides a change plate that causes the airflow of the projecting and light-receiving sections to be directed upstream with respect to the flow, and generates an upward airflow from the upstream side so that the airflow does not directly collide with the projecting and light-receiving sections; It is characterized by being provided with a capture plate that further collides with and raises the rising air.

[Effect]

The alarm of this invention has the above-mentioned characteristic configuration, so that the main airflow flowing inside the change plate collides at the tip and overcomes it, and negative pressure is generated on the downstream side and tries to descend, but the outside of the change plate The flowing air flows around and collides with each other, and further collides with the trapping plate, lifting the main airflow and generating an upward airflow, so that the light emitting and receiving parts are protected at a height more than twice the height of the change plate and the trapping plate. becomes.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Reference numeral 1 is a side wall of a road tunnel, and 2 is a radiation type fire detector equipped with a solar cell, etc., and a light receiving window 21 serving as a light receiving portion thereof is provided so as to protrude from the side wall 1. 22 is a V-shaped change plate that generates an upward air flow that prevents the air flow 3 from directly colliding with the light-receiving part 21; 23 is a plate-shaped capture plate that further collides with the above-mentioned upward air flow and moves it upward; They are provided sequentially from the upstream side with respect to the flow. The V-shaped change plate 22 is arranged so that its open end side faces the upstream side of the airflow 3.
The capture plate 23 is provided so that its wall surface faces the light receiving window 21 serving as a light receiving section. In addition, the airflow 3 is
Wind speed flowing in a certain direction inside the tunnel is 2 to 8 m/s
ventilation flow.

Next, the functions of the change plate 22 and the capture plate 23 will be explained. A ventilation flow 3 flowing from a fixed direction along the tunnel side wall 1 is divided into airflow flowing inside and outside the plate wall at a change plate 22 provided in the fire detector 2. When the main airflow containing floating dust flowing inside the changing plate 22 passes over the changing plate 22, negative pressure is generated on the secondary side thereof, resulting in a flow as shown by an arrow 31. However, the airflow flowing outside the changing plate 22 increases its speed and flows into the negative pressure area from the left and right as shown by the arrow 33, colliding with each other and rising, and further colliding with the capture plate 23 and rising, so that The main airflow shown by is greatly lifted to generate an ascending airflow shown by arrow 32. In this case, the height is raised to approximately three times the height of the change plate 22 and the capture plate 23.

In FIG. 3, the change plate 22 is formed in an H-shape, and the capture plate 23 is formed in a U-shape. This is an embodiment in which the end side faces the upstream side of the airflow 3, and the open end side of the U-shaped capture plate 23 faces the upstream side of the airflow. The airflow 33 flowing outside flows into the flowing airflow 31 and further collides with and lifts the capture plate 23, generating a large upward airflow as shown by the arrow 32, which is similar to the embodiments shown in FIGS. 1 and 2. . Moreover, such an effect is achieved by the change plate 22 and the capture plate 2.
3 is formed in a V-shape, and the open end sides of the plates 22 and 23 are respectively oriented toward the upstream side of the airflow 3. This problem also occurs in the case shown in FIG. The airflow flowing to the outside of the V-shaped capture plate 2
Since it is efficiently captured at 3, a larger updraft is generated.

Furthermore, in the above embodiment, a case was described in which the radiation type fire detector is installed in a road tunnel, but other fire alarms equipped with a similar light-receiving part or light-emitting part such as a light-receiving window or a reflector can also be used. Alternatively, the present invention can be implemented in a detector for an anti-theft device, that is, an alarm equipped with an emitting and light-receiving section that is easily contaminated by airborne dust contained in the airflow.

〔effect〕

The alarm of this invention is configured and operates as described above, so that the main airflow flowing inside the change plate collides at the tip and overcomes it, and negative pressure is generated on the downstream side of the change plate and tries to descend, but the main air flow flowing inside the change plate The airflow flowing through the plate wraps around the airflow and collides with each other, which then collides with the trapping plate to lift it up and generate an upward airflow. This has the effect of providing an alarm equipped with anti-fouling means.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the alarm of the present invention installed on the side wall of a road tunnel, Fig. 2 is a perspective view of the alarm of Fig. 1, and Figs. 3 and 4 are views of other alarms. A perspective view of the embodiment, FIG. 5 is a perspective view of a conventional alarm device. 1...Tunnel side wall, 2...Fire detector, 21
...light receiving window, 22...change plate, 23...capture plate,
3...Airflow.

Claims (1)

[Scope of Claims] 1. A radiation or optical alarm for a fire or theft prevention device in which a projecting or receiving part is provided on the ceiling or wall of a building through which airflow flows from a certain direction. A change plate is provided on the upstream side with respect to the airflow of the area, and a change plate is provided from the upstream side to generate an upward airflow that does not directly project the airflow and collide with the light receiving area, and a capture plate that causes this upward airflow to further collide and rise. An alarm device equipped with means for preventing contamination of the emitting and light-receiving parts. 2 Consisting of a V-shaped change plate and a plate-shaped capture plate, the V-shaped change plate is arranged such that the open end side thereof faces upstream with respect to the airflow, and the wall surface of the capture plate is An alarm device comprising means for preventing contamination of the projecting and light-receiving portions according to claim 1, wherein said means is provided so as to face the projecting and light-receiving portions. 3 Consisting of an H-shaped change plate and a U-shaped capture plate, one U-shaped open end side of the H-shaped change plate is opened toward the light emitting and light receiving sections, and the other 2. An alarm device equipped with means for preventing contamination of a projection and light receiving section as set forth in claim 1, wherein the open end side of the U-shape and the open end side of the U-shaped capture plate are directed toward the upstream side of the airflow. 4 The invention is comprised of a V-shaped change plate and a V-shaped capture plate, and the V-shaped open ends of the change plate and capture plate are directed toward the upstream side of the airflow. An alarm device equipped with means to prevent contamination of the light emitting and receiving parts.