Well Point Dewatering Systems

Additional Details

As shown in Well Point De-Watering Systems consists of a number of well points spaced along a trench or around an excavation site, all connected to a common header which is attached to one or more well point pupms. Well point assemblies-made up of a well point, screen, riser pipe and swing joint with tuning-are generally installed by jetting. They provide for entry of water into the system by creation of a partial vacuum. The water is then pumped off through the header pipe. A well point pump is a combination of two pumps, one of which pumps water from the header and the other of which is a vacuum pump to remove air which enters the system. Control of air is important, as excessive air causes cavitation which reduces pump efficiency. Dewatering pumps are designed specifically for the dewatering function. They are available in capacities from 50-200 ltrs per second. Well point systems are frequently the logical and economic choice for dewatering construction sites where the required lowering of ground water level is on the order of 15 feet or less. Greater lifts are possible by lowering the water in two or more stages. The 15-foot lift restriction results from the fact that the water is lifted by difference between ambient air pressure and the lowered pressure created by the pump. These incorporates a simple non return valve encased in aluminum alloy jet head which opens to direct flow of water jet and closes when the suction starts. This is designed for rapid penetration by jetting.