Conductivity cell for particle study device

Abstract

The conductivity cell is utilized in a particle study device of the type wherein liquid electrolyte containing particles is caused to traverse an electrical sensing zone of small dimensions, sensing electrodes being located on either side of the sensing zone. The conductivity cell includes two electrodes situated in the electrolyte and being coupled to an electrical sensing circuit including the sensing electrodes. The resistance across the sensing electrodes and the resistance across the conductivity cell electrodes are connected in series with the power source and function as a voltage divider. The junction between the two resistances is coupled to a signal detecting amplifier so that a change in the conductivity of electrolyte will cause a change in both of the resistances whereby the voltage at the junction between the two resistances is essentially constant. To obtain a relatively high resistance between the conductivity cell electrodes, the conductivity cell includes a long and narrow column of electrolyte between the conductivity cell electrodes. In one embodiment, the long and narrow column of electrolyte is situated in a length of serpentine tubing.

Dependencies are inferred from the claim text.