US 4,397,725 A · Apparatus for measuring electrochemical activity

Abstract

Apparatus is disclosed for measuring the electrochemical activity of a liquid, for example, the hydrogen ion activity or pH value of blood. A disposable cartridge includes spaced indicating and reference electrodes which develop electrical properties as a function of the electrochemical activity. The cartridge carries a capsule containing an electrolyte solution. A machine for measuring the electrochemical activity includes a socket in a pivoting door for receiving the cartridge. When the door is pivoted into a closed position, the capsule is automatically crushed thereby covering the electrodes with the solution. The breaking of the capsule triggers an electronic measurement of the resultant electrical properties that develop between the two electrodes. This calibration factor is stored and used to compute the electrochemical characteristics of the sample when it is introduced into the cartridge to cover the indicating electrode. In one embodiment a photocell arrangement emits light which is absorbed by the sample so as to automatically trigger the final measurement when the sample is in contact with the indicating electrode. The cartridge is heated to a predetermined temperature to insure the accuracy of the measurement. Preferably, the socket assembly includes heater pads on opposing printed circuit boards which come into contact with the cartridge when the door is closed. The cartridge has a thermally conductive insert adjacent the tip of the indicating electrode which is contacted by a sensor in the socket to provide signals to a microcomputer which is adapted to control the measurement process. The heater system is selectively disabled by the microcomputer to insure the accuracy of the measurement.

Claims17

Dependent claims

Apparatus for measuring electrochemical activity in a liquid, said apparatus being adapted for use with a cartridge having spaced indicating and reference electrodes bridged by a chamber and including an ampule containing electrolyte solution carried by upper portions of said cartridge, said apparatus comprising:

a housing with a door pivotally mounted on said housing;
socket means mounted on the door for receiving said cartridge in an upright position when the door is pivoted outwardly from the housing;
and
crusher means for breaking the ampule when the door is pivoted inwardly towards said housing to thereby introduce the electrolyte into the chamber to cover the electrodes, said crusher means comprising a generally U-shaped member defining lip and leg portions and means for pivotally mounting said member in said housing such that said lip is arranged to be struck by said cartridge when the door is swung into the closed position thereby pivoting said leg portion against the ampule to break same.

1 more element

Apparatus for measuring electrochemical activity of a liquid, said apparatus being adapted for use with a cartridge having spaced indicating and reference electrodes arranged to be immersed in an electrolyte solution, with said cartridge further being adapted to guide a capillary tube containing the liquid over the tip of the indicating electrode, said apparatus comprising:

a socket assembly for receiving said cartridge;
thermistor means for sensing the temperature of the cartridge;
heater means for heating the cartridge to a predetermined temperature;
detector means for detecting when the electrodes have been immersed in the electrolyte solution;
microcomputer means coupled to said detector and said thermistor and being responsive to signals therefrom to measure an electrical property developed between the electrodes to establish a calibration factor;
means for storing the calibration factor;
sending means for sensing when the liquid in the capillary tube has contacted the indicating electrode, said sensor means being coupled to said microcomputer to trigger a subsequent electrode measurement, with said microcomputer being adapted to calculate the electrochemical activity of the liquid from said measurement;
and
means for providing a visual indication of the calculated electrochemical activity of the liquid.

6 more elements

Dependencies are inferred from the claim text.

Apparatus for measuring electrochemical activity

Life of this patent

Apparatus for measuring electrochemical activity

Life of this patent

Abstract

Claims17