Processes and methods for binary opposing buoyancy for large underwater lift applications

Abstract

A deep-sea apparatus for retrieving deep-sea nodules is provided. The deep-sea apparatus includes an opposer configured to provide static buoyancy to the deep-sea apparatus. The deep-sea apparatus further includes a thruster coupled to the opposer, the thruster configured to provide dynamic buoyancy to the deep-sea apparatus. The deep-sea apparatus also includes a variable load and a gas supply system that includes a gas cylinder connected to a gas valve of the opposer, where the gas supply system is configured to inject a predetermined amount of gas from the gas cylinder to the opposer in response to a change in a vertical position of the opposer caused by a mass change in the variable load.

What is claimed is: 
     
         1 . An apparatus, comprising:
 an opposer configured to provide static buoyancy to the apparatus when the apparatus is underwater, the opposer comprising a gas valve and a release valve;   a thruster coupled to the opposer, the thruster configured to provide dynamic buoyancy to the apparatus when the apparatus is underwater;   a variable load; and   a gas supply system comprising a gas cylinder connected to the gas valve of the opposer, wherein the gas supply system is configured to inject a predetermined amount of gas from the gas cylinder to the opposer via the gas valve in response to a change in a vertical position of the opposer caused by a mass change in the variable load.   
     
     
         2 . The apparatus of  claim 1 , wherein the gas supply system is further configured to operate the release valve to release gas from the opposer in response to another change in a vertical position of the opposer caused by a mass change in the variable load. 
     
     
         3 . The apparatus of  claim 2 , wherein the change is a downward change in the vertical position of the opposer and the other change is an upward change in the vertical position of the opposer. 
     
     
         4 . The apparatus of  claim 1 , wherein the opposer is a lift bag. 
     
     
         5 . The apparatus of  claim 1 , wherein the gas is a gas mixture. 
     
     
         6 . The apparatus of  claim 5 , wherein the gas mixture is air. 
     
     
         7 . The apparatus of  claim 1 , wherein the thruster is configured to provide upward or downward thrust when the gas supply system injects gas in the opposer. 
     
     
         8 . The apparatus of  claim 1 , wherein the thruster is bi-directional reversible thruster. 
     
     
         9 . The apparatus of  claim 1 , wherein gas supply system operates with pressure compensated gas regulation. 
     
     
         10 . The apparatus of  claim 1 , wherein the predetermined amount of gas is based on the mass change of the variable load and a hydrostatic pressure of water surrounding the opposer. 
     
     
         11 . The apparatus of  claim 1 , wherein the gas valve is a one-way valve disposed at a base of the opposer and the release valve is disposed on a side surface of the opposer. 
     
     
         12 . A method for maintaining an underwater vehicle neutrally buoyant under variable load conditions, the method comprising:
 changing a mass of a variable load attached to the underwater vehicle;   in response to changing the mass of the variable load, producing lift with an inflatable lift bag attached to the underwater vehicle by injecting an amount of gas into the inflatable lift bag, wherein the amount of gas injected is based on the mass change of the variable load and a hydrostatic pressure of water surrounding the lift bag; and   while injecting the gas, applying an amount of thrust to oppose changes to a vertical position of the underwater vehicle until the lift produced by the amount of gas injected becomes stable.   
     
     
         13 . The method of  claim 12 , wherein injecting the mount of gas into the inflatable lift bag comprises injecting gas from a gas cylinder attached to the underwater vehicle via a one-way valve disposed at a bottom surface of the inflatable bag. 
     
     
         14 . The method of  claim 12 , wherein applying thrust comprises operating a bi-directional reversible thruster attached to the underwater vehicle. 
     
     
         15 . The method of  claim 12 , wherein changing the mass of the variable load comprises increasing the mass of the variable load. 
     
     
         16 . The method of  claim 12 , wherein producing lift comprises producing static buoyancy. 
     
     
         17 . The method of  claim 12 , wherein applying thrust comprises producing dynamic buoyancy. 
     
     
         18 . The method of  claim 12 , wherein injecting the amount of gas into the inflatable lift bag comprises injecting a gas mixture into the inflatable lift bag. 
     
     
         19 . The method of  claim 18 , wherein the gas mixture is air. 
     
     
         20 . The method of  claim 12 , wherein the produced lift becomes stable after about 30 s or less.