Abstract: A non metallic flow through electrodeless conductivity sensor is provided with a conduit having primary and secondary process fluid flow paths to form a fluid loop. At least one drive and one sense toroid surround the conduit on the fluid loop. Voltage supplied to the drive toroid induces a current in the sense toroid via the fluid loop to eliminate any need for metallic electrodes in contact with the process fluid. At least one additional drive and/or sense toroid is disposed on the fluid loop to enhance induction. Optionally one or more sense coils are disposed about the conduit outside of the fluid loop to cancel out stray electrical noise. An optional conductor disposed along the conduit detects any fluid leakage through changes in resistance thereof. A temperature detector is supported within an electrically non-conductive holder extending into the fluid flow path, so that the detector is free from physical contact with the fluid.

Abstract: In an ionic-activity sensor, an osmotic pump drives a reference-cell electrolyte to flow through an interface with the solution to be measured. This minimizes contamination of the reference cell by that solution. The driving force results from expansion of an electrolytic-agent reservoir into which solvent from a solvent reservoir diffuses through a semi-permeable membrane. The electrolytic-agent reservoir contains an electrolytic-agent solution in which a quantity of undissolved is disposed to keep the electrolytic-agent solution saturated as solvent diffuses into it.