| 摘要 |
This invention is a smoke or fire detector that first utilizes a signal that is indicative of a detected smoke or fire condition to operate an air moving device to purge the detectors photocell or ionization chamber and to thereafter allow an additional signal indicative of a detected smoke or fire condition within a predetermined time frame to provide an alarm signal. The smoke or fire detector avoids many false alarm situations by placing a cyclic purge switching control system between the smoke or fire detector and the alarm signal device. The cyclic purge switching control system sequentially connects the signal indicative of a detected smoke or fire condition between the air moving device such as a fan and the alarm signal device.
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