摘要 |
A smoke alarm on the scattered radiation principle. Having a measuring field (5), accessible to smoke particles, in a measuring chamber, at which field the radiation direction of a radiation transmitter (6) is aimed, and scattered radiation occurring in the measuring field (5) can be received by a radiation receiver (7); the measuring chamber includes a portion of the hollow ellipsoid (3) which is mirror-coated on the inside; the measuring field (5) is disposed at the first focal point (1) of the hollow ellipsoid; the radiation receiver (7) is disposed at the second focal point (2) of the hollow ellipsoid (3).
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