Apparatus and method for determining the amount of liquid contained in a storage tank

An apparatus for determining the amount of liquid contained in a tank, the tank having an interior defining a predetermined relationship between liquid level and volumetric content, the apparatus comprising

• an elongate member having a longitudinal axis and being at least partially disposed inside the tank, said elongate member having a longitudinal edge defining a profile corresponding to said predetermined relationship between liquid level and volumetric content, at least a portion of said profile being non-linear;
• a buoyant member operably connected to said elongate member to cause said elongate member to be displaced generally along said longitudinal axis in response to displacement of said buoyant member resulting from a corresponding change in liquid level;
• and
• a device for measuring a distance between said longitudinal edge and a reference plane aligned substantially parallel to said longitudinal axis when the liquid in the tank is at various levels, said distance being proportional to the volumetric content of liquid in the tank at sad various levels.

An apparatus for determining the amount of liquid contained in a tank, the tank having an interior defining a predetermined relationship between liquid level and volumetric content, the apparatus comprising:

• an elongate member having a longitudinal axis and being at least partially disposed inside the tank, said elongate member having a longitudinal edge defining a profile corresponding to said predetermined relationship between liquid level and volumetric content;
• a buoyant member operably connected to said elongate member to cause said elongate member to be displaced generally along said longitudinal axis in response to displacement of said buoyant member resulting from a corresponding change in liquid level;
• and
• a device for measuring a distance between said longitudinal edge and a reference plane aligned substantially parallel to said longitudinal axis when the liquid in the tank is at various levels, said distance being proportional to the volumetric content of liquid in the tank at said various levels, said measuring device includes a stationary bearing assembly and a movable bearing assembly with said elongate member positioned therebetween, said longitudinal edge engaging said movable bearing assembly in an abutting relationship so as to horizontally displace said movable bearing assembly as said elongate member is displaced generally along said longitudinal axis, said measuring device further includes a linear gauge adapted to measure the horizontal displacement of said movable bearing assembly relative to said reference plane.

An apparatus for determining the amount of liquid contained in an enclosed tank, the tank having an interior defining a predetermined relationship between liquid level and volumetric content, the apparatus comprising:

• a tube at least partially disposed inside the tank, said tube having:
• a side wall defining an inner region and an exterior surface,
• a bottom plate closing a lower end of said tube to prevent admission of the liquid into said inner region, and
• an open end facing upwardly and protruding from the tank so as to isolate said inner region of said tube from the interior of the tank;
• an elongate member having a longitudinal axis and slidable within said inner region of said tube, said elongate member having a longitudinal edge defining a profile corresponding to said predetermined relationship between liquid level and volumetric content, said predetermined relationship between liquid level and volumetric content being at least partially defined by a non-linear function between a variation in liquid level and the resulting change in the volumetric content of liquid contained in the tank;
• a float slidable along said exterior surface of said tube;
• said elongate member and said float having interacting features which cause said elongate member to be displaced generally along said longitudinal axis in response to displacement of said float resulting from a change in liquid level;
• and
• a device for measuring a distance between said longitudinal edge and a reference plane aligned substantially parallel to said longitudinal axis when the liquid in the tank is at a selected level, said distance being proportional to the volumetric content of liquid in the tank at said selected level.

A method for determining the amount of liquid contained in a tank, the tank interior defining, a predetermined relationship between liquid level and volumetric content, the method comprising:

• providing an elongate member having a longitudinal axis and being at least partially disposed inside the tank, the elongate member having a longitudinal edge defining a profile corresponding to the predetermined relationship between liquid level and volumetric content, the predetermined relationship between liquid level and volumetric content being at least partially defined by a non-linear function between a variation in liquid level and the resulting change in the volumetric content of liquid contained in the tank;
• displacing the elongate member generally along the longitudinal axis in response to a corresponding change in liquid level;
• and
• measuring a distance between the longitudinal edge and a reference plane aligned substantially parallel to the longitudinal axis when the liquid in the tank is at various levels, the distance being proportional to the volumetric content of liquid in the tank at the various levels.

An apparatus for determining the amount of liquid contained in a tank, the tank having interior walls defining a predetermined relationship between liquid level and volumetric content, the apparatus comprising:

• an elongate member having a longitudinal axis and being disposed in the tank, said elongate member having a longitudinal edge defining a varying profile corresponding to said predetermined relationship between liquid level and volumetric content, said predetermined relationship between liquid level and volumetric content being at least partially defined by a non-linear function between a variation in liquid level and the resulting change in the volumetric content of liquid contained in the tank;
• means for displacing said elongate member generally along said longitudinal axis in response to a corresponding change in liquid level;
• and
• means for measuring a distance between said longitudinal edge and a reference plane aligned parallel to said longitudinal axis when the liquid in the tank is at various levels, said distance being proportional to the volumetric content of the liquid in the tank at said various levels.