Probe for controlling the level of electrically conductive liquids

Claim 2

A probe for detecting the level of electrically conductive liquids in a container comprising: a measuring electrode rod; a housing for mounting said electrode rod to the wall of said container, said electrode rod extending through a wall of said housing into said container; a plurality of spaced-apart insulating discs radially surrounding said electrode rod; a plurality of annular and conductive distance spacers insulatedly surrounding said electrode rod and disposed between said insulating discs, said insulating discs and said distance spacers being secured inside the container so as to seal and insulate said electrode rod from said housing; an electrical bridge circuit coupled to said electrode and housing for liquid level indication; and a counter electrode arranged at a defined distance from said electrode rod and said distance spacers, wherein one of said distance spacers comprises a compensating electrode forming a resistance path common with the liquid of the container with respect to the counter electrode, said resistance path serves as a resistor in one branch of the bridge circuit and the resistance path between said electrode rod and said counter electrode serves as a resistor in another branch of the bridge circuit and said two branches are connected in series to each other with respect to a power source coupled to the bridge circuit.

Claim 3

The probe as recited in claim 1 wherein said distance spacers define annular gaps around the electrode rod; and comprising a control electrode disposed between said electrode rod and said discs, and indicating means coupled to said control electrode on the one hand and to said electrode rod on the other hand for indicating changes in electrical resistance in said annular gaps around said electrode rod.

Claim 4

The probe as recited in claim 2 wherein one of said distance spacers comprises said control electrode.

Claim 5

A probe for detecting the level of electrically conductive liquids in a container comprising: a measuring electrode rod; a housing for mounting said electrode rod to the wall of said container, said electrode rod extending through a separation wall of said housing into said container; a plurality of spaced-apart insulating discs radially surrounding said electrode rod; at least one annular and conductive distance spacer insulatedly surrounding said electrode rod and disposed between said insulating discs, said insulating discs and said distance spacer being secured inside the container and an axial support face of said electrode rod so as to seal and insulate said electrode rod from said housing; an electrical bridge circuit coupled to said electrode and housing for liquid level indication; a counter electrode spaced from said electrode rod and said at least one distance spacer; wherein one of said at least one distance spacer comprises a compensating electrode forming a resistance path common with the liquid of the container with respect to the counter electrode, said resistance path serves as a resistor in one branch of the bridge circuit, and a path of resistance between said electrode rod and said counter electrode serves as a resistor in another branch of the bridge circuit; and a power source coupled to said bridge circuit and across said two branches, the latter connected in series to each other with respect to said power source.

Claim 6

A probe for detecting the level of electrically conductive liquids in a container comprising: a measuring electrode rod; a housing for mounting said electrode rod to the wall of said container, said electrode rod extending through a separation wall of said housing into said container; a plurality of spaced-apart insulating discs radially surrounding said electrode rod; at least one annular and conductive distance spacer insulatedly surrounding said electrode rod and disposed between said insulating discs, said insulating discs and said distance spacer being secured inside the container and an axial support face of said electrode rod so as to seal and insulate said electrode rod from said housing; an electrical bridge circuit coupled to said electrode and housing for liquid level indication; a counter electrode spaced from said electrode rod and said at least one distance spacer; wherein one of said at least one distance spacer comprises a compensating electrode forming a resistance path common with the liquid of the container with respect to the counter electrode, said resistance path serves as a resistor in one branch of the bridge circuit, and a path of resistance between said electrode rod and said counter electrode serves as a resistor in another branch of the bridge circuit; and a power source coupled to said bridge circuit and across said two branches, the latter connected in series to each other with respect to said power source.

Claim 7

The probe as recited in claim 4 wherein said at least one distance spacer constitutes a plurality of distance spacers; said electrode rod includes a smaller diameter portion and a larger diameter portion connected to each other through said separating wall, said smaller diameter portion being spaced from said plurality of distance spacers; and said counter electrode and said compensating electrode are horizontally installed through a vertical wall of said housing.