Research On New Measure Of Running In A Large Pumping Station For Drainange Over The Hump

Since 1960's hundreds of large pumpmg stations for drainage have been built near the rivers and seas in China. These drainage pumping stations often use siphon outlet conduit .They consist of up-segment, top-hump,down-segment, which are the same with the pumping station with levees. The height of the hump is decided according to the height designing water level of outlet pool and so the hump can prevent the backward flow. There is a vacuum breaker on the top of the hump. It breaks vacuum on the hump and cuts off flow, which cannot resist the current and runs reliably. However in the late years, the pumping stations operate continually over the hump because of the change of the hydrology conditions and the elevation of the water level. On the other hand with the development of economy, the drainage standard of distract is increased and so pumping stations urgently need starting and draining when the water level is over the hump for abating the disaster of internal water logging. So they have to be researched and settled that the pumping station operate on starting and suspending period over the hump for the safety of the pumping stations. Therefore, this paper set up a series of integrated lash-up measure.In this paper all kinds of cut-off flow ways were analyzed and appraised when the large drainage pumping stations operate over the hump. And technical problems of traditional cut-off flow ways in practice are indicated. We come up with a series of new cut-off flow means of using compressed air and a new loose-leaf rapid-gate running alone or together to finish pumping set starting, suspending and preventing the water in the river from backwards flow. A theoretical study was made on the dynamic characteristics of pumping system during the hydraulic transient process of starting and suspending. Mathematical models are presented to express the characteristics based on the systematical analysis of electromotor, axial pump and outlet conduit dynamic characteristics, and numerical calculation methods are promoted. The exhaust equipment, the compressed air cut-off flow system and the new loose-leaf rapid-gate were designed with the results of the transient process. The case which the new loose-leaf rapid-gate operated alone is analyzed and it's mathematical model is drown during the gate dropping. In the end, according to YuMaTou pumping station in JiaYu county HuBei province, the calculations are done that compressed-air cut-off flow system in the water level over the hump finishes starting and suspending transient process. The calculations are also done for the raising and dropping of the loose-leaf rapid-drop gate when the water level is over the hump. A series way is offered for designing of compressed-air equipment and loose-leaf rapid-drop gate.