JPH0219902Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an ionization smoke detector that detects fire based on the presence of smoke.

In recent years, there has been a demand for a fire detector suitable for detecting fires occurring inside large electronic devices such as large computer devices. If anything,
These large computer devices are not only expensive, but also play a central role in various industrial fields and cannot be left out of service for long periods of time. Therefore, there is a demand for a fire detector that can detect fires. Ionization smoke detectors are suitable for such fire detectors because they can detect aerosols generated in the early stages of a fire, but they can be installed in limited spaces such as inside computer equipment. Currently, a small ionization type smoke detector has not yet been manufactured.

Therefore, there are several obstacles to miniaturizing the ionization type smoke detector, but in the ionization type smoke detector according to this invention, smoke can enter the cover body without reducing the sensitivity of the detector. It has holes formed in it.

In other words, conventional ionization smoke detectors ionize the atmosphere between a pair of electrodes using a radiation source, apply a voltage between the electrodes, and detect smoke from the decrease in the ionic current flowing there due to the influence of smoke. It is structured according to the principle. However, due to its principle, when strong wind blows into the smoke detection section formed between these electrodes, ions flow out of the detection section, so the ion current decreases in the same way as when smoke flows in, causing malfunction. It was hot. Therefore, in order to prevent the outside air from going directly to the smoke detection part, a blocking body is installed at a position corresponding to a plurality of holes for introducing smoke made around the cover body that covers this detection part. was.

However, in the case where the entire sensor is miniaturized, which is the object of this invention, the above-mentioned configuration becomes a major obstacle. This is because when trying to make the outer shape of the cover body smaller, it is necessary to narrow the gap between the aperture and the blocking body, but at the same time, the gap between the periphery of the blocking body and the periphery of the opening This is because it also narrows the gap formed in the smoke inflow hole.

An embodiment of the ionization type smoke detector according to this invention that solves the above problems will be explained in detail below based on the drawings. Fig. 1 shows an embodiment of the ionization type smoke detector according to this invention. FIG. 2 is a side view with a part of the example in cross section, and FIG. 2 is an end view of a section taken along the line A-A' in FIG. In this embodiment, the atmosphere between an external electrode 2 around which a plurality of smoke inflow holes 1 are bored and an electrode 3 facing it is ionized by a radiation source (not shown), and a trace amount of smoke is constantly An ionic current is flowing. The smoke detection section 4 is configured to detect changes in this ion current due to smoke. The entire smoke detection section 4 is covered with a cover body 5 made of an insulating material such as synthetic resin, and is protected from electrical contact from the outer malleolus, and is also protected from the outside air through a plurality of gaps 6 formed around it. This prevents outside air from directly flowing into the smoke detection section 4.

The feature of the ionization type smoke detector according to this invention lies in this gap 6.

That is, a plurality of openings 7 are bored around the outer periphery of the cover body 5 to form an intake port for outside air.
Inside the cover body 5 corresponding to this opening 7, a smoke detection section is placed at a slight distance from the peripheral edge 9 of this opening 7, and viewed from the outside in a direction perpendicular to the smoke detection section 4. A blocking body 8 having a size such that 4 cannot be seen is located. In this embodiment, the blocking body 8 is integrally formed with the cover body 5, but it goes without saying that this invention is not limited to this embodiment. An inclined surface 10 is formed on the peripheral edge 9 of the opening 7 so that the cross-sectional area of the opening 7 expands from the outside to the inside, and a gap is formed between the peripheral edge 9 and the peripheral edge 11 of the blocking body 8. Sufficient spacing is ensured even in the portion S where the distance is the smallest.

In addition, in this embodiment, the opening 7 on the inclined surface is
However, if the inclination direction is the same, the blocking body 8 may be provided on the circumferential edge 11 side.
If both of the holes 11 are sloped surfaces, the distance between the opening 7 and the blocking body 8 can be further narrowed.

As described above, the ionization type smoke detector according to this invention suppresses direct flow of outside air to the smoke detection part by only forming one or both of the peripheral edge of the cover body and the peripheral edge of the blocking body into an inclined surface. Since a smoke inflow hole is formed that can take in a sufficient amount of outside air, and the distance between the opening and both peripheral edges of the blocking body can be narrowed, the overall shape of the cover body can be made smaller. Furthermore, it is possible to downsize the ionization type smoke detector itself while maintaining sufficient performance.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view of an embodiment of the ionization type smoke detector according to the invention, and FIG. 2 is an end view of the section taken along line A-A' in FIG. Identical parts are designated by the same reference numerals throughout both figures. 4... Smoke detection part, 7... Opening, 5... Cover body, 8... Blocker, 11... Peripheral part of blocker, 9
...Periphery of the opening, 6...Gap, 10...Slanted surface.

Claims (1)

[Scope of utility model registration request] A cover body that houses a smoke detection unit that detects smoke based on changes in ionic current between electrodes caused by smoke, and has a plurality of openings around the cover body, and outside air passes straight through each of the openings to the smoke detection unit. In an ionization type smoke detector, the above-mentioned apertures facing each other are provided with a peripheral edge of the aperture and a plurality of blocking bodies installed in each aperture so as to block the aperture with a gap therebetween. and an ionization type smoke sensor, characterized in that one or both of the peripheral edges of the blocking body are formed as inclined surfaces to enlarge the distance between the gaps.