Surface level measuring device

Claim 2

Surface level measuring device comprising a measuring sensor heatable to a given temperature and insertable into a liquid, the surface level of which is to be measured, whereby the given temperature of said measuring sensor is changed, and means for determining the surface level of the liquid in accordance with the change in the given temperature, said measuring sensor comprising a sheathed conductor formed with a resistance wire having a temperature-dependent resistance and a heating wire distinct from said resistance wire traversible by an electric current, and a support rod having projections extending therefrom, said sheathed conductor being wound around said support rod in engagement with said projections.

Claim 3

Surface level measuring device according to claim 1 wherein the liquid is received in a vessel, and including a second sheathed conductor wound around said support rod, said second sheathed conductor formed with a resistance wire for compensating for the temperature of the vessel, said resistance wire of said second sheathed conductor being connected in a bridge circuit with the resistance wire of the first-mentioned sheathed conductor heatable by the heating wire thereof.

Claim 4

Surface level measuring device according to claim 1 wherein said support rod is formed with a helical notch, said projections extending out of said helical notch.

Claim 5

Surface level measuring device comprising a measuring sensor heatable to a given temperature and insertable into a liquid, the surface level of which is to be measured, whereby the given temperature of said measuring sensor is changed, and means for determining the surface level of the liquid in accordance with the change in the given temperature, said measuring sensor comprising a sheathed conductor formed with a plurality of resistance wires having a temperature-dependent resistance and a plurality of heaTing wires traversible by an electric current, and a support rod having projections extending therefrom, said sheathed conductor being wound around said support rod in engagement with said projections.

Claim 6

Surface level measuring device comprising a measuring sensor heatable to a given temperature and insertable into a liquid, the surface level of which is to be measured, whereby the given temperature of said measuring sensor is changed, and means for determining the surface level of the liquid in accordance with the change in the given temperature, said measuring sensor comprising a sheathed conductor formed with a plurality of resistance wires having a temperature-dependent resistance and a plurality of heaTing wires traversible by an electric current, and a support rod having projections extending therefrom, said sheathed conductor being wound around said support rod in engagement with said projections.

Claim 7

Surface level measuring device for determining the surface level of a body of liquid comprising a carrier rod, a plurality of sheathed conductors serving as a measuring sensor wound around said carrier rod, at least one said sheathed conductor being a heating wire traversible by an electric current and at least one conductor formed of resistance wire, distinct from said heating wire, having a temperature-dependent resistance and at least one unheated sheathed conductor formed of resistance wire having a temperature-dependent resistance, said heated and unheated sheathed conductors wound around said carrier rod extending below and above said surface level of said body of liquid when said carrier rod is disposed in said body of liquid, a bridge circuit for comparing the resistance value of said heated conductor having a temperature-dependent resistance with the resistance of said resistance wire of said unheated conductor, said heated and unheated sheathed conductors both being exposed to the temperatures above and below the surface level in the vessel whose liquid level is to be measured, said resistance wire having a temperature-dependent resistance of said heated sheathed conductor being disposed in a bridge branch and said resistance wire of said unheated sheathed conductor being disposed in another bridge branch of the resistance measuring bridge.

Claim 8

Surface level measuring device for determining the surface level of a body of liquid comprising a carrier rod, a plurality of sheathed conductors serving as a measuring sensor wound around said carrier rod, at least one said sheathed conductor being a heating wire traversible by an electric current and at least one conductor formed of resistance wire, distinct from said heating wire, having a temperature-dependent resistance and at least one unheated sheathed conductor formed of resistance wire having a temperature-dependent resistance, said heated and unheated sheathed conductors wound around said carrier rod extending below and above said surface level of said body of liquid when said carrier rod is disposed in said body of liquid, a bridge circuit for comparing the resistance value of said heated conductor having a temperature-dependent resistance with the resistance of said resistance wire of said unheated conductor, said heated and unheated sheathed conductors both being exposed to the temperatures above and below the surface level in the vessel whose liquid level is to be measured, said resistance wire having a temperature-dependent resistance of said heated sheathed conductor being disposed in a bridge branch and said resistance wire of said unheated sheathed conductor being disposed in another bridge branch of the resistance measuring bridge.