| 摘要 |
PURPOSE:To reduce the pressure loss at the nozzle section by utilizing the differential pressure to be produced through operation of a jet fan to change the curvature of nozzle suitably for the blowing direction. CONSTITUTION:Through operation of a jet fan, differential pressure DELTAP is produced in the jet fan. At the blowing side, the pressure immediately after an impeller 2 is fed through a pressure communication tube 6 into an air chamber 7. Here the differential pressure DELTAP is positive while the nozzle 8 at the blowing side is made of resilient member such as ruber, thereby a moving ring 5 is pushed forward to increase the curvature R of said nozzle 8. While at the suction side, the differential pressure DELTAP will be negative to reduce the curvature R of nozzle 9 at the suction side. In such a manner, proper curvature of nozzle is formed to reduce the pressure loss at the nozzle section resulting in the improvement of fan efficiency and noise reduction.
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