| 摘要 |
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.
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