| 摘要 |
<p>A water backflow preventing system is provided for a given area having a sewer line for receiving rain and other water where the sewer line is incapable of carrying, without backup, a given flow rate of water. The sewer line (4A or 4B) is provided at a given point (D) therealong with at least one overflow opening (sewer opening into which standpipe 35 extends) into which opening water which cannot be handled by the sewer line will rise and overflow. Water storage tank means (22 or 24) are buried in the ground below the sewer line and into which the overflow water from said opening will drain and be temporarily stored. The storage tank means (22 or 24) have a volume to store many thousands of gallons of water which cannot otherwise flow in the sewer line. A pump (36) is placed in the bottom of the storage tank means. Various float switches (FS', FS) are placed in different parts of the system for controlling the pump. They are arranged to prevent the operation of the pump when water backup valve conditions exist in the sewer line and to automatically render the pump means operative when backflow conditions disappear from the sewer line so that the storage tank means can be substantially emptied and accommodate overflow conditions which can be caused by a subsequent rainstorm.</p> |
