US 9,310,327 B2 · Toroidal conductivity probe with integrated circuitry

Abstract

An apparatus and process for making noncontact measurements of liquid conductivity are disclosed. This apparatus forms a conductivity cell and uses two toroids, one to generate a magnetic field and another to sense the magnetic field, placed in an enclosure which allows liquid to pass through it for measurement. Ground planes constructed preferably of printed circuit boards with conductive layers are used to reduce capacitive coupling between the toroids and provide better shielding. Circuitry on or near these circuit boards are used to convert local, low level signals from a sensing toroid to signals which can be more readily passed to and from a recording system or operator without degradation. Sensors on or near these circuit boards can be used to sense environmental conditions in order to improve operation and stability of the conductivity cell. Methods and apparatus for increasing circuit sensitivity and calibrating the sensor are also disclosed.

Claims41

Dependent claims

An apparatus for measuring the conductivity of fluids via noncontact means, the apparatus comprising:

a housing, containing two or more toroids coaxially stacked along a central opening in said housing in order to form a single bore for fluid passage, at least one toroid having an input for voltage and current in order to generate a magnetic field, said magnetic field generating toroid herein referred to as a signal toroid, and at least one toroid having means for magnetic flux sensing by means of an output for voltage and current, said flux sensing toroid herein referred to as a sense toroid;
and
a magnetically transparent enclosure around said toroids;
and
means for applying an electrical current to said signal toroid in order to generate a magnetic field;
and
means for bringing a signal out from said sense toroid to indicate conductivity of a fluid;
and
at least one electrically insulating layer, each layer having a single bore for fluid passage, each layer being coaxially stacked between said toroids along said central opening in said housing, each of said insulating layers containing at least two conductive layers;
and
each conductive layer used as a separate electrical ground.

8 more elements

A method for measuring the conductivity of fluids via noncontact means with high sensitivity, by using a conductivity measuring cell including two or more toroids coaxially stacked along a central opening in a housing in order to form a single bore for fluid passage, a conducting electrical shield between at least two of said toroids, one of said toroids designated a signal toroid and one designated a sense toroid, a source of electrical current and two or more sets of wires, comprising the steps of:

applying said electrical current to wires wrapped around said signal toroid in order to generate a magnetic field in the fluid passage;
sensing said magnetic field using wires wrapped around said sense toroid to generate a low level electrical signal in said wires;
and
shielding said signal toroid from said sense toroid by using a PCB board having at least one conductive layer acting as a ground plane to form said conducting electrical shield.

1 more element

Dependencies are inferred from the claim text.

Toroidal conductivity probe with integrated circuitry

Life of this patent

Toroidal conductivity probe with integrated circuitry

Life of this patent

Abstract

Claims41