| 摘要 |
<p>PURPOSE: To prevent a drainage machine house or a drainage basin from being submerged even in the case of an excessively flooded area by taking capacity greater than shaft necessary for a pump driver and pump shut-off operation, and operating a pump under an overload greater than planned flow rate at the time of rain quantity which exceeds planned pump house capacity. CONSTITUTION: A drainage pump 1 to be used is of variable speed or moving blade type, and is designed to be operated beyond prescribed revolutions or designed blade angle within the capacity range of a driver 3, and permit drainage which exceeds planned drainage at the time of building a machine house. The driver 3 to be used has a capacity greater than shaft power necessary for pump shut-off operation to permit overload operation. A change in inflow water quantity is monitored through a pressure gauge 5 and a water level gauge 4 provided at a suction tank 2 and an upstream water passage. While rainwater quantity larger than planned drainage is flowing in, drainage operation is carried out under an overload condition by the driver 3.</p> |
