| 摘要 |
PURPOSE:To suppress the generation of abnormal noise caused by a Helmholtz's resonance in a valve when it is opened, by connecting a blind passage, which displays a resonance silencing effect, with a valve chamber in a valve case interposed in an circulative path or with a chamber in series to the valve chamber. CONSTITUTION:A blind passage 18 of predetermined internal diameter and length is connected with a valve chamber 11 of the first valve 7 or a pressure chamber 14 of the second valve 9 interposed in series to the valve chamber 11 in the first air circulative path 6. In this way, a silencing effect is recognized when a passage 8 including a joint pipe 18a is formed to a length of 7-11cm, while a frequency decreases to about 185Hz in a region displaying the silencing effect by the blind passage 18, generating no sound of bothering tone and pressure as compared with the frequency of abnormal noise, generated when the blind passage 18 is not connected, increasing to a high noisy level of about 650Hz. |
