Patent ID: 9719528
Date: 2017-08-01
CPC Classifications: B01D,E02F,E21C,F04F

Claim:
1. A bubble lift system for lifting a substance in solid or liquid form from a water bottom or under the water bottom to a vicinity of a water surface, comprising: a riser pipe through which the substance is lifted, the riser pipe having an inside, a lower end portion into which the substance is suctioned, and an upper end portion above the water surface from which the substance is discharged, means for injecting a gas into a lower side portion of the riser pipe to cause the gas to rise in the form of bubbles that reduce the pressure of a fluid column inside the rise pipe, and suck a substance into the riser pipe at the lower end portion of the riser pipe and lift the substance to a place above the water surface, means provided at the upper end portion of the riser pipe for applying a pressure to the inside of the riser pipe at the upper end portion to thereby suppress an increase in a volume ratio of the bubbles to a fluid mixture rising inside the riser pipe in a shallow water region, and means provided at an upper side portion of the riser pipe for generating a rotational flow of the fluid mixture rising inside the riser pipe to thereby gather the bubbles and gas towards a swirl axis by a centrifugal effect, and to discharge the gathered bubbles and gas to the outside of the riser pipe from a ventilation pipe having an opening portion at the swirl axis, wherein the means provided at the upper end portion of the riser pipe for applying a pressure to the inside of the riser pipe includes means for setting an application pressure thereof within such a preset pressure range that an injection volume of the gas injected into the lower side portion of the riser pipe has no need to be controlled dynamically according to a suctioning condition, that a flow velocity of the fluid mixture is kept within a predetermined range even when only surrounding water is suctioned, and that even when only a substance is suctioned, a design upper limit of specific gravity of the fluid mixture is still higher than the specific gravity of the suctioned substance.