Level detector with multiple magnetically activated switches

Claim 1

An apparatus for detecting position comprising in combination : (a) an elongated tubular container; (b) a first elongated electrically conducting member disposed following the length of said elongated tubular container and enclosed therein; (c) a second elongated electrically conducting member disposed following the length of said elongated tubular container and enclosed therein, wherein at least one of the first and second elongated electrically conducting members has a high specific ohmic resistance; (d) a plurality of normally open switches disposed within said elongated tubular container at regular intervals in a parallel circuit arrangement intermediate said first and second elongated electrically conducting members, each of said plurality of normally open switches establishing electrical connection between said first and second elongated electrically conducting members when said normally open switch is closed, wherein the earth's gravitational pull acting on the normally open switches keeps the normally open switches at open position in the absence of a magnetic force field, and a magnetic force field closes the normally open switches; (e) a marker guided by said elongated tubular container in a sliding relationship, said marker including at least one magnet creating a magnetic force field penetrating into the interior of said elongated tubular container; (f) means for measuring ohmic resistances of two electric circuits respectively including in series one portion of said at least one elongated electrically conducting member having a high specific ohmic resistance intermediate one extremity thereof and the normally open switch closed by the magnetic force field of said marker, the normally open switch closed by the magnetic force field of said marker and a portion of the other elongated electrically conducting member, and in series the other portion of said at least one elongated electrically conducting member intermediate the normally open switch closed by the magnetic force field of said marker and the other extremity opposite to said one extremity, the normally open switch closed by the magnetic field of said marker and said a portion of the other elongated electrically conducting member; and (g) means for determining the position of said marker from the measured ohmic resistances of the two electric circuits, wherein contact resistance of the normally open switch closed by the magnetic field of said marker is eliminated in arithmetics providing the position of the marker.

Claim 2

An apparatus for detecting position comprising in combination : (a) an elongated tubular container; (b) a first elongated electrically conducting member disposed following the length of said elongated tubular container and enclosed therein; (c) a second elongated electrically conducting member disposed following the length of said elongated tubular container and enclosed therein, wherein at least one of the first and second elongated electrically conducting members has a high specific ohmic resistance; (d) a plurality of normally open switches disposed within said elongated tubular container at regular intervals in a parallel circuit arrangement intermediate said first and second elongated electrically conducting members, each of said plurality of normally open switches establishing electrical connection between said first and second elongated electrically conducting members when said normally open switch is closed, wherein the earth's gravitational pull acting on the normally open switches keeps the normally open switches at open position in the absence of a magnetic force field, and a magnetic force field closes the normally open switches; (e) a marker guided by said elongated tubular container in a sliding relationship, said marker including at least one magnet creating a magnetic force field penetrating into the interior of said elongated tubular container; (f) means for measuring ohmic resistances of two electric circuits respectively including in series one portion of said at least one elongated electrically conducting member having a high specific ohmic resistance intermediate one extremity thereof and the normally open switch closed by the magnetic force field of said marker, the normally open switch closed by the magnetic force field of said marker and a portion of the other elongated electrically conducting member, and in series the other portion of said at least one elongated electrically conducting member intermediate the normally open switch closed by the magnetic force field of said marker and the other extremity opposite to said one extremity, the normally open switch closed by the magnetic field of said marker and said a portion of the other elongated electrically conducting member; and (g) means for determining the position of said marker from the measured ohmic resistances of the two electric circuits, wherein contact resistance of the normally open switch closed by the magnetic field of said marker is eliminated in arithmetics providing the position of the marker.

Claim 5

An apparatus for detecting position comprising in combination : (a) an elongated tubular container; (b) a first elongated electrically conducting member disposed following the length of said elongated tubular container and enclosed therein; (c) a second elongated electrically conducting member disposed following the length of said elongated tubular container and enclosed therein, wherein at least one of the first and second elongated electrically conducting members has a high specific ohmic resistance; (d) a plurality of normally open switches disposed within said elongated tubular container at regular intervals in a parallel circuit arrangement intermediate said first and second elongated electrically conducting members, each of said plurality of normally open switches establishing electrical connection between said first and second elongated electrically conducting members when said normally open switch is closed, wherein mechanical spring force included in the normally open switch keeps the normally open switch at open position in the absence of a magnetic force field and a magnetic force field closes the normally open switch; (e) a marker guided by said elongated tubular container in a sliding relationship, said marker including at least one magnet creating a magnetic force field penetrating into the interior of said elongated tubular container; (f) means for measuring ohmic resistances of two electric circuits respectively including in series one portion of said at least one elongated electrically conducting member having a high specific ohmic resistance intermediate one extremity thereof and the normally open switch closed by the magnetic force field of said marker, the normally open switch closed by the magnetic force field of said marker and a portion of the other elongated electrically conducting member, and in series the other portion of said at least one elongated electrically conducting member intermediate the normally open switch closed by the magnetic force field of said marker and the other extremity opposite to said one extremity, the normally open switch closed by the magnetic force field of said marker and said a portion of the other elongated electrically conducting member; and (g) means for determining the position of said marker from the measured ohmic resistances of the two electric circuits, wherein contact resistance of the normally open switch closed by the magnetic force field of said marker is eliminated in arithmetics providing the position of said marker.

Claim 6

An apparatus for detecting position comprising in combination : (a) an elongated tubular container; (b) a first elongated electrically conducting member disposed following the length of said elongated tubular container and enclosed therein; (c) a second elongated electrically conducting member disposed following the length of said elongated tubular container and enclosed therein, wherein at least one of the first and second elongated electrically conducting members has a high specific ohmic resistance; (d) a plurality of normally open switches disposed within said elongated tubular container at regular intervals in a parallel circuit arrangement intermediate said first and second elongated electrically conducting members, each of said plurality of normally open switches establishing electrical connection between said first and second elongated electrically conducting members when said normally open switch is closed, wherein mechanical spring force included in the normally open switch keeps the normally open switch at open position in the absence of a magnetic force field and a magnetic force field closes the normally open switch; (e) a marker guided by said elongated tubular container in a sliding relationship, said marker including at least one magnet creating a magnetic force field penetrating into the interior of said elongated tubular container; (f) means for measuring ohmic resistances of two electric circuits respectively including in series one portion of said at least one elongated electrically conducting member having a high specific ohmic resistance intermediate one extremity thereof and the normally open switch closed by the magnetic force field of said marker, the normally open switch closed by the magnetic force field of said marker and a portion of the other elongated electrically conducting member, and in series the other portion of said at least one elongated electrically conducting member intermediate the normally open switch closed by the magnetic force field of said marker and the other extremity opposite to said one extremity, the normally open switch closed by the magnetic force field of said marker and said a portion of the other elongated electrically conducting member; and (g) means for determining the position of said marker from the measured ohmic resistances of the two electric circuits, wherein contact resistance of the normally open switch closed by the magnetic force field of said marker is eliminated in arithmetics providing the position of said marker.

Claim 9

An apparatus for detecting position comprising in combination: (a) an elongated tubular container; (b) a first elongated electrically conducting member disposed following the length of said elongated tubular container and enclosed therein; (c) a second elongated electrically conducting member disposed following the length of said elongated tubular container and enclosed therein, wherein at least one of the first and second elongated electrically conducting members has a high specific ohmic resistance; (d) a plurality of normally open switches disposed within said elongated tubular container at regular intervals in a parallel circuit arrangement intermediate said first and second elongated electrically conducting members, each of said plurality of normally open switches establishing electrical connection between said first and second elongated electrically conducting members when said normally open switch is closed, wherein said normally open switch stays open in the absence of a magnetic force field and a magnetic force field closes the normally open switch; (e) a marker guided by said elongated tubular container in a sliding relationship, said marker including at least one magnet creating a magnetic force field penetrating into the interior of said elongated tubular container; and (f) means for measuring ohmic resistances of two electric circuits respectively including in series first portion of said first and second elongated electrically conducting members intermediate one extremity thereof and the normally open switch closed by the magnetic force field of said marker and the normally open switch closed by the magnetic force field of said marker, and in series second portions of said first and second elongated electrically conducting members intermediate the normally open switch closed by the magnetic force field of said marker and the other extremity opposite to said one extremity and the normally open switch closed by the magnetic force field of said marker; and (g) means for determining the position of said marker from the measured ohmic resistances of the two electric circuits, wherein contact resistance of the normally open switch closed by the magnetic force field of said marker is eliminated in arithmetics providing the position of said marker.

Claim 10

An apparatus for detecting position comprising in combination: (a) an elongated tubular container; (b) a first elongated electrically conducting member disposed following the length of said elongated tubular container and enclosed therein; (c) a second elongated electrically conducting member disposed following the length of said elongated tubular container and enclosed therein, wherein at least one of the first and second elongated electrically conducting members has a high specific ohmic resistance; (d) a plurality of normally open switches disposed within said elongated tubular container at regular intervals in a parallel circuit arrangement intermediate said first and second elongated electrically conducting members, each of said plurality of normally open switches establishing electrical connection between said first and second elongated electrically conducting members when said normally open switch is closed, wherein said normally open switch stays open in the absence of a magnetic force field and a magnetic force field closes the normally open switch; (e) a marker guided by said elongated tubular container in a sliding relationship, said marker including at least one magnet creating a magnetic force field penetrating into the interior of said elongated tubular container; and (f) means for measuring ohmic resistances of two electric circuits respectively including in series first portion of said first and second elongated electrically conducting members intermediate one extremity thereof and the normally open switch closed by the magnetic force field of said marker and the normally open switch closed by the magnetic force field of said marker, and in series second portions of said first and second elongated electrically conducting members intermediate the normally open switch closed by the magnetic force field of said marker and the other extremity opposite to said one extremity and the normally open switch closed by the magnetic force field of said marker; and (g) means for determining the position of said marker from the measured ohmic resistances of the two electric circuits, wherein contact resistance of the normally open switch closed by the magnetic force field of said marker is eliminated in arithmetics providing the position of said marker.