Buoyancy control systems and methods for submersible objects

A method of controlling buoyancy of a submersible object comprising the steps of:

• arranging a housing within the submersible object;
• arranging first and second pistons within the housing to define a control chamber;
• supporting the first piston for movement within the housing such that movement of the first piston changes a volume of the control chamber;
• supporting a second piston for movement within the housing such that movement of the second piston changes the volume of the control chamber;
• providing a source of pressurized working fluid;
• operating first and second valves to allow pressurized working fluid to displace the first piston to alter a buoyancy of the submersible object in a first range of depths;
• and
• operating first and second valves to allow pressurized working fluid to displace the first and second pistons to alter the buoyancy of the submersible object in a second range of depths.

A buoyancy control system for a submersible object comprising:

• a housing fixed relative to the submersible object;
• a first piston supported by the housing such that movement of the first piston changes a volume of a control chamber;
• a second piston movably supported by the housing such that movement of the second piston changes the volume of the control chamber;
• a source of pressurized working fluid;
• and
• first and second valves are operatively connected between the source of pressurized fluid and the first and second pistons to allow pressurized working fluid to displace at least one of the first and second pistons relative to the housing;
• wherein
• the buoyancy control system is operable in a shallow mode in a first range of depths and in a deep mode in a second range of depths;
• in the shallow mode, the first and second valves are controlled to allow fluid to flow from the source of pressurized fluid to the first piston such that the pressurized fluid displaces the first piston to alter the volume of the control chamber and thus a buoyancy of the buoyancy control system;
• and
• in the deep mode, the first and second valves are controlled to allow fluid to flow from the source of pressurized fluid to the first and second pistons such that the pressurized fluid displaces both of the first and second pistons to alter the volume of the control chamber and thus the buoyancy of the buoyancy control system.

A buoyancy control system comprising:

• a housing;
• a first piston supported by the housing such that
• the first piston and the housing define a first working chamber, and
• movement of the first piston changes a volume of a control chamber;
• a second piston supported by the housing such that
• the second piston and the housing define a second working chamber, and
• movement of the second piston changes the volume of the control chamber;
• an accumulator;
• a pump connected to the first working chamber;
• a first valve connected between the pump and the accumulator;
• and
• a second valve connected between the pump and the second working chamber;
• whereby
• the buoyancy control system is operable in a shallow mode in a first range of depths and in a deep mode in a second range of depths;
• in the shallow mode, displacement of the first piston alters a volume of the control chamber and thus a buoyancy of the buoyancy control system;
• and
• in the deep mode, displacement of the first and second pistons alters a volume of the control chamber and thus the buoyancy of the buoyancy control system.

A method of controlling buoyancy of a submersible object comprising the steps of:

• arranging a housing within the submersible object;
• arranging first and second pistons within the housing to define a control chamber;
• supporting the first piston for movement within the housing such that
• the first piston and the housing define a first working chamber, and
• movement of the first piston changes a volume of the control chamber;
• supporting a second piston for movement within the housing such that
• the second piston and the housing define a second working chamber, and
• movement of the second piston changes the volume of the control chamber;
• connecting a pump to the first working chamber;
• connecting a first valve between the pump and an accumulator;
• connecting a second valve between the pump and the second working chamber;
• operating the second valve to prevent fluid flow into and out of the second working chamber to displace the first piston to alter the volume of the control chamber and thus a buoyancy of the submersible object in a first range of depths;
• and
• operating the second valve to allow fluid flow into and out of the second working chamber to displace the first and second pistons to alter the volume of the control chamber and thus a buoyancy of the submersible object in a second range of depths.

A buoyancy control system for a submersible object comprising:

• a housing fixed relative to the submersible object;
• a first piston supported by the housing such that
• the first piston and the housing define a first working chamber, and
• movement of the first piston changes a volume of a control chamber;
• a second piston supported by the housing such that
• the second piston and the housing define a second working chamber, and
• movement of the second piston changes the volume of the control chamber;
• an accumulator;
• a pump connected to the first working chamber;
• a first valve connected between the pump and the accumulator;
• and
• a second valve connected between the pump and the second working chamber;
• whereby
• the buoyancy control system is operable in a shallow mode in a first range of depths and in a deep mode in a second range of depths;
• in the shallow mode, displacement of the first piston alters the volume of the control chamber and thus the buoyancy of the buoyancy control system;
• and
• in the deep mode, displacement of the first and second pistons alters the volume of the control chamber and thus the buoyancy of the buoyancy control system.