| 摘要 |
PURPOSE:To inhale the inside air from almost the whole circumference of a bell mouth as well as to aim at the promotion of high air quantity and low noise, by selecting each of inside and outside air intakes installed in an outer case where an inner case is housed, according to upper and lower sliding positions of the inner case. CONSTITUTION:At the time of taking in the outside air, an inner case 4 is slidably fitted in a cylindrical outer case 3, and since negative pressure is not yet impressed on an actuator 6, this inner case 4 is pressed down by a spring 7. Therefore, an inside air intake 13 is closed, while an outside air intake 12 is opened and interconnected to a conducting port 16 by another conducting port 14. Accordingly, the outside air is inhaled in a bell mouth 11 by way of the outside air intake 12 and these conducting ports 14 and 16. On the other hand, when the negative pressure is impressed on the actuator 6 and the inner case 4 is pulled up, the outside intake 12 is closed while the inside intake 13 is opened instead. Therefore, the inside air can be inhaled from almost the whole circumference an and around the bell mouth 11. |
