| 摘要 |
PURPOSE:To prevent the variation of sensitivity by dust in the ionization type smoke sensor for machinery, by providing electrodes opposed in the direction of air stream and disposing a source of radiant rays on the lower stream surface of the electrode of the upper stream side. CONSTITUTION:Wind volume of air stream blown in by the fan 23 is controlled by the wind volume controlling board 14 and the air stream is entered in the main body 7 of the ionization type smoke sensor from the inflow opening 10 of the body 7. Then, said stream enters in the ion room A formed between the electrodes 17, 18 after passing through the upper stream side electrode 17 attached with a vent and is discharged out of the room with the fan 23 after passing through the lower stream side electrode 18. On this occasion, dust in the stream does not settle on the radiant rays source 19 because the source 19 is provided on the face of the lower stream side of the upper stream side electrode 17 and accordingly, sensitivity is not changed. Next, on occasion of emitting smoke in the machinery, the smoke passes through the course of the air stream and is rapidly invaded in the body 7. Then, said smoke enters in the room A and the circuit 20 is operated when the ion current is decreased by said smoke. With such construction, variation of sensitivity by the dust in the air stream can be prevented. |
