| 摘要 |
<p>A vacuum drain system including a collecting tank and a sewage drain vacuum conduit line for conveying sewage from service connections to the collecting tank under the influence of vacuum in the system. Each service connection for admitting sewage includes a suction valve which also admits a volume of air to facilitate movement of sewage in the system. In order to prevent accumulation of sewage during prolonged periods of low usage of the system, such as at night, an auxiliary aeration system is provided for introducing a volume of air independently of the air admitted through operation of the suction valves.</p> |
