| 摘要 |
A backflow prevention device includes at least one backflow prevention unit. The backflow prevention unit includes a frame, a first edge shutter plate, a second edge shutter plate and plural intermediate shutter plates. The frame includes an airflow channel. If the first inner sidewall is disposed over the second inner sidewall, the first edge shutter plate and the plural intermediate shutter plates are configured to open or close the airflow channel, and the slab of the second edge shutter plate is inactive. Whereas, if the second inner sidewall is disposed over the first inner sidewall, the second edge shutter plate and the plural intermediate shutter plates are configured to open or close the airflow channel, and the slab of the first edge shutter plate is inactive. |
| 主权项 |
1. A backflow prevention device, comprising:
at least one backflow prevention unit, said backflow prevention unit comprising:
a frame comprising an airflow channel, a first extension wall and a second extension wall, wherein said airflow channel has an inner surface, and said inner surface comprises a first inner sidewall and a second inner sidewall, wherein said first inner sidewall and said second inner sidewall are opposed to each other, and said first extension wall and said second extension wall are connected to the side edges of said first inner sidewall and said second inner sidewall, respectively; anda first edge shutter plate, a second edge shutter plate and plural intermediate shutter plates disposed within said airflow channel of said frame, wherein said first edge shutter plate is arranged adjacent to said first inner sidewall and said first extension wall, said second edge shutter plate is arranged adjacent to said second inner sidewall and said second extension wall, and said plural intermediate shutter plates are arranged between said first edge shutter plate and said second edge shutter plate, wherein each of said shutter plates has a rotating shaft pivotally coupled to said inner surface and a slab rotatable with respect to an axis of said rotating shaft, the distance between said rotating shafts of said first edge shutter plate and a neighboring intermediate shutter plate is shorter than the distance between said rotating shafts of every two adjacent intermediate shutter plates, and the distance between said rotating shafts of said second edge shutter plate and a neighboring intermediate shutter plate is shorter than the distance between said rotating shafts of every two adjacent intermediate shutter plates,when said first inner sidewall is disposed over said second inner sidewall, said first edge shutter plate and said plural intermediate shutter plates are configured to open or close said airflow channel, and said second extension wall is configured to prevent the airflow from flowing through a space between said second edge shutter plate and said second inner sidewall, wherein when said first edge shutter plate and said plural intermediate shutter plates are configured to close said airflow channel, a first acute angle is formed between said second edge shutter plate and said neighboring intermediate shutter plate, wherein said second edge shutter plate contacts said second inner sidewall, when said second inner sidewall is disposed over said first inner sidewall, said second edge shutter plate and said plural intermediate shutter plates are configured to open or close said airflow channel, and said first extension wall is configured to prevent the airflow from flowing through a space between said first edge shutter plate and said first inner sidewall, wherein when said second edge shutter plate and said plural intermediate shutter plates are configured to close said airflow channel, a second acute angle is formed between said first edge shutter plate and said neighboring intermediate shutter plate wherein said first edge shutter plate contacts said first inner sidewall. |
