Abstract: A method for controlling the chemical treatment of a solution comprises the steps of feeding a treatment chemical into the solution, applying an external voltage across a reference electrode and a working electrode of a voltammetric sensor while the electrodes are immersed in the solution, measuring a current that flows through the working electrode, converting the measured current into a feedback signal indicative of the concentration of treatment chemical in the solution, and using the feedback signal to control the rate of feeding the treatment chemical.

Abstract: Method and apparatus for electrochemical monitoring of oxidizing agents, such as nitrite, or reducing agents in a water system and for controlling concentration levels for protecting surfaces exposed to the water. The apparatus includes a probe for selective exposure to fresh water samples of the system. The probe is connected to an analyzer that operates the probe and measures agent concentration by a chronoamperometry technique. A controller selectively feeds an agent to the water system in accordance with a set point to maintain a desired concentration level.

Abstract: An instrument and method for measuring chemical properties, the instrument having electrodes suitable for immersion in a chemical solution. A voltage source and a current-sensing circuit are connected to the electrodes to measure the current produced in the solution in response to a voltage applied to the electrodes to determine a value of the chemical in the solution. The instrument and method further include background compensation for offsetting the value of the analyte by an amount which is reflective of the background value of the solution. The background value is stored in an internal memory of the instrument so that when new experimental measurements are taken, the measurements are immediately offset by the background portion of the new experimental measurements. This allows operation of the instrument at high gain levels, resulting in a broad dynamic range and greater useful precision in the output signal.

Abstract: A biosensing meter is enabled to receive a sample strip that includes a sample well with an analyte reactant therein and electrodes in contact therewith. The biosensing meter includes an excitation supply for supplying potentials to a sample strip electrode. A sense amplifier is also provided for connection to another electrode of an inserted sample strip and produces an output signal indicative of sensed currents when an analyte containing fluid is present in the strip's sample well. A pluggable memory key is insertable into the meter and includes a plurality of stored parameter values and procedure routines that control operations of the meter. A microprocessor is responsive to a procedure routine and parameter values accessed from the pluggable memory key to cause the excitation supply to apply a plurality of potentials for preset durations, both the values of the potentials and the time duration of their application determined from parameter values derived from the memory key.

Abstract: A biosensing meter receives a sample strip that includes electrically isolated sense and excitation electrodes bridged by a reaction zone. When a drop of biological sample fluid is placed in the reaction zone, a plurality of fail/safe tests are performed. A drop size test is performed by a circuit that detects the size of the drop placed in the reaction zone. The circuit both detects that a drop has been placed in the reaction zone and further measures a test current level, after a delay, to determine that the drop size is sufficient to enable hydration of reactants in the reaction zone. Subsequently, during the reaction, a "delta" current change is measured at succeeding sample time. This test measures the difference between succeeding current samples during a measurement time. If each succeeding sample is not less than preceding sample by a delta value, a determination is made that the current is not monotonically decreasing and the test is aborted.

Abstract: A diagnostic electrode actively generates test signals to be supplied to analyzer circuitry. The electrode emulates a disposable sensor associated with the analyzer during a normal mode of normal operation. The diagnostic device generates predetermined signals for an output interface of the device using a power supply disposed within the device. The diagnostic module can be designed to produce voltage signals, current signals, or light signals to be received by the analyzer, depending on the type of analyzer to which the diagnostic electrode is to be associated.

Abstract: The present invention relates to an electrochemical cell and a related state of charge indicator comprising an electrochemically generated display. The state of charge indicator comprises two electrical contacts and an electrochemically generated display connected therebetween. The display comprises an electrochemical cell that may be permanently connected to a main cell in a parallel configuration via the contacts. The condition of the main cell may thus be continuously displayed on the indicator.

Abstract: The device for the simultaneous detection of dissimilar gas components contains a number of electrochemical, three-electrode measuring cells with a common electrolyte, that are formed from a number of working electrodes with a common counter-electrode and a common reference electrode. Measured values are generated with the aid of a potentiostatic evaluation circuit that also adjusts and sets the potentials at the working electrodes. The current signals correlated with the gas concentrations to be measured are displayed with the aid of current-measuring instruments 11.sub.1 . . . 11.sub.n in the lines to the working electrodes 5.sub.1 . . . 5.sub.n. At the same time it is important that all three-electrode measuring cells have a common counter-electrode 3 and a common reference electrode 4, and that the potentiostatic evaluation circuit 6 contains control loops 7.sub.1 . . . 7.sub.n which maintain the potentials of the working electrodes 5.sub.1 . . . 5.sub.

Abstract: An apparatus and method for rapidly identifying the chemical compositions and concentrations of solutions and for discriminating among solutions of different chemical compositions and concentrations of the solution is monitored by applying across a predetermined volume of the solution a predetermined voltage for a predetermined time after which the application of voltage is terminated and the voltage time characteristic measured across the solution as the voltage decays is compared with an empirically obtained voltage versus time characteristic for a solution having a standardized composition and/or concentration.

Abstract: An electrochemical analysis system for analytical determination of a constituent of a sample includes a disposable analysis element and an evaluation unit. The disposable analysis element includes an isolating carrier with a sample application device for applying a sample thereto for analysis, and at least one sensor with a working electrode and a reference electrode for sensing electrical properties of the sample. The analysis element also includes a connection zone with connecting contacts which are connected to the electrodes via connecting leads. The evaluation unit includes an analysis element connector for electrically connecting to the connecting contacts of the analysis element, and a measuring and evaluation circuit for measuring electrical variation characteristics of the electrical properties sensed by the sensor on the analysis element.

Abstract: An apparatus for the simultaneous measurement of a plurality of ionic concentrations can utilize a test station having a common support sheet for supporting a plurality of ion selective electrodes, reference electrode and pH responsive electrode. Simultaneous measurements can be taken at the same time from a single sample and the pH reference electrode can validate the operative range of an ion selective electrode.

Abstract: An automatic chemistry analyzer includes a flow cell mounted so that flow through the cell and tubing connected to the cell is visible from the front of the housing. The electrolytes to the cell are removably plugged into the cell from their rear. The probe aspirating sample fluid into an injection cell is simultaneously washed by diluent and the diluent mixes with the fluid sample. Waste fluid from the flow cell is fed to a basin which then feeds under gravity to a waste drain. A ratio pump is formed by selected syringes which are band driven to deliver accurately prerequisite volumes of reagents to the flow cell. The solution ground to the system is on the inlet line for sample adjacent the entrance to the flow cell of fluid thereby minimizing electronic noise. Only two motive means are necessary, one to effect horizontal and rotational movement of the sample tray, and a second to effect vertical motion of a crane mounted probe operative between sample cups and an injection cell.

Abstract: The present invention comprises an electrochemical metering apparatus that provides for convenient storage and presentation of the analytical electrode, simple assembly, and two calibration modes. The apparatus includes an electrode storage and presentation assembly that permits the user to introduce the electrode into a sample solution while simultaneously observing the meter's output, and store the electrode when not in use. All structural components are intended to fit together with interlocking tabs and windows. A serial port fits within the construction of the main housing without the need for bolts, and battery clips that depend directly from the circuit board obviate the need for wiring connections. The present invention also features two calibration modes. A "segment addition" mode permits separation of the voltage/concentration curve into individually plotted regions, the number of which depends on the number of reference solutions used in the calibration procedure.

Abstract: An automatic chemistry analyzer includes a flow cell mounted so that flow through the cell and tubing connected to the cell is visible from the front of the housing. The electrolytes to the cell are removably plugged into the cell from their rear. The probe aspirating sample flud into an injection cell is simultaneously washed by diluent and the diluent mixes with the fluid sample. Waste fluid from the flow cell is fed to a basin which then feeds under gravity to a waste drain. A ratio pump is formed by selected syringes which are band driven to deliver accurately prerequisite volumes of reagents to the flow cell. The solution ground to the system is on the inlet line for sample adjacent the entrance to the flow cell of fluid thereby minimizing electronic noise. Only two motive means are necessary, one to effect horizontal and rotational movement of the sample tray, and a second to effect vertical motion of a crane mounted probe operative between sample cups and an injection cell.

Abstract: The electromotive force of a standard liquid for correction is measured. Both before and after this measurement, the electromotive force of a reference liquid is measured at least once. A calibration curve is prepared based on the resultant data. The calibration curve is used to convert the electromotive force difference between a test liquid (the ion concentration of which is to be measured) and the reference liquid. Both before and after the measurement of the electromotive force of the test liquid, the electromotive force of the reference liquid is measured at least once. By so doing, the electromotive force difference between the test liquid and the reference liquid is obtained. The ion concentration of the test liquid can be detected accurately by plotting the electromotive force difference against the calibration curve.

Abstract: The present invention comprises an electrochemical metering apparatus that provides for convenient storage and presentation of the analytical electrode, simple assembly, and two calibration modes. The apparatus includes an electrode storage and presentation assembly that permits the user to introduce the electrode into a sample solution while simultaneously observing the meter's output, and store the electrode when not in use. All structural components are intended to fit together with interlocking tabs and windows. A serial port fits within the construction of the main housing without the need for bolts, and battery clips that depend directly from the circuit board obviate the need for wiring connections. The present invention also features two calibration modes. A "segment addition" mode permits separation of the voltage/concentration curve into individually plotted regions, the number of which depends on the number of reference solutions used in the calibration procedure.

Abstract: An apparatus and method for directly indicating the gold content of a metal object employs a receptacle or cell into which is deposited a small portion of an electrolyte solution. The solution preferably contains copper and iron ions, acetic acid and hydrogen peroxide. At the bottom of the cell is a first electrode preferably of pure gold in contact with the solution. The first electrode is electrically connected to an electronic measuring and indicating apparatus. The metal object to be tested is connected by a metal spring clip to the electronic apparatus and then a portion of the object is immersed in the solution so that it forms the second electrode of an electrochemical cell. The electronic apparatus measures the voltage generated in the electrochemical cell after the voltage has stabilized and indicates by indicating apparatus the gold content of the metal object.

Abstract: A disposable cartridge for use in a clinical sensing arrangement interfaces electrically with a host instrument capable of responding to electrical signals generated by detector devices incorporated in the cartridge upon exposure to calibrant fluids and/or clinical fluids under examination. The cartridge includes a passage linking a reservoir of calibrant fluid to the detector devices and further linking the device to a closed container for fluid which has been conveyed past the devices. A fluid under test can be introducted into the cartridge through the passage wall at a location disposed between the reservoir and the detector devices.

Abstract: Apparatus for electrolytic processing of materials, includes an electrolytic processing bath, plural first electrodes, at least one second electrode, and a power supply for supplying time multiplexed power to the electrodes. The power supply may include a pulse width modulator or a pulse position modulator and is operative to control the relative amounts of time that the respective electrodes are energized for electroplating, electropolishing, and the like. Current control and bath composition control are provided. A method for electrolytic processing of materials includes placing plural first electrodes in an electrolytic processing bath, placing at least one second electrode in such bath, and at different times supplying power between at least one of such first electrodes and such at least one second electrode and supplying power between at least another of such first electrodes and such at least one second electrode.

Abstract: A method and apparatus for defining the molecular chemical make up of a liquid sample, based on electrostatic charges of emission. Three spaced electrodes are brought into contact with the surface of a liquid to be tested. Two electrodes are wired in series through a usual cone speaker to the terminals of an audio amplifier. A third electrode is wired in series through a variable oscillator to the amplifier auxiliary input terminal. This overall regenerative feedback circuit will result in unique patterns of coded pulses at the amplifier speaker output corresponding to the composition of the liquid, which can be observed on an oscilloscope or recorded and compared with known compositions. This apparatus can be useful in defining molecular diseases when the electrodes are touched to the wetted skin of an animal, plant tissue or blood sample. The apparatus can also be adapted to a neological method of electronic gene mapping.

Abstract: Apparatus and method for monitoring stress in a coating of material. The apparatus has a fluid-filled chamber and a deformable diaphragm on which the coating is applied forming a wall of the chamber, the fluid, which is generally incompressible, having a pressure due to pressing of the diaphragm against the fluid which is indicative of stress in the coating. The apparatus also includes a pressure transducer in communication with the fluid for sensing the fluid pressure and converting the fluid pressure to electrical signals whereby the electrical signals are indicative of the stress in the coating of material.

Abstract: A modular multi-channel automated medical analyzer device is disclosed, characterized by use of an ion selective electrode and/or enzymatic electrode/wash cell system which permits rapid analysis of various substances of interest contained within undiluted body fluids such as whole blood, serum and/or plasma. The ion selective electrode and/or the enzymatic electrode are disposed upon a probe which automatically axially reciprocates downwardly in a simple manipulative motion between an open-ended reference wash cell and a sample cup bearing the body fluid specimen to be analyzed. The wash cell includes an inlet port and one or more outlet ports through which is circulated an aqueous solution bearing a known concentration of the substance to be measured to provide a reference calibration medium as well as a probe washing medium.

Abstract: A microprocessor-controlled pH and ion concentration meter is disclosed with improved calibration and testing procedures. For calibration (standardization), the meter stores number pairs (pX.sub.a, E.sub.a), (pX.sup.b, E.sub.b) where the pX values may be pH values (e.g., 4.00 and 7.00) and the E values are expressed in mV/deg K. When multiple standard values are stored, remeasuring one (e.g., replacing E.sub.a1 by E.sub.a2) can be used to update the others (e.g., E.sub.b1 to E.sub.b2) without remeasurement by applying the formula:E.sub.b2 =E.sub.b1 +(E.sub.a2 -E.sub.a1).Additionally, the meter can be tested for excessive internal bias current by measuring the potential (V1) when the meter is connected to a circuit of low impedance and the potential (V2) when the meter is connected to a circuit of the same voltage source but of known high impedance and having the meter compare (V2-V1) to a preset limit value.

Abstract: A clinical chemistry analyzer system for blood chemistry analysis is disclosed. Two major parts comprise the system. One part is a discardable sensor cartridge which contains a bank of sensors, calibration fluid containers, conduit means and an external peristallically pumpable tube section. The other part is an analysis machine which interfaces with the discardable cartridge and has means to drive the peristaltic pump as well as means to interface with the sensors of the cartridge to provide a readout therefrom. The system is adapted to be made part of a heart/lung machine sustaining a patient in order to sample and monitor the venous and arterial blood flow thereof.

Abstract: The present invention is an improved method and apparatus for condition sensing and displaying a numeric value associated with the sensed condition wherein the improvement comprises (1) circuitry calibrating the display of the numerical value associated with the sensed condition to a numerical value associated with the sensed condition in a normal ambient environment, while the sensor is within the normal ambient environment; and (2) circuitry for calibrating the display of the numerical value of the sensed condition to a numerical value associated with the sensed condition in a known offset environment which is different than the normal ambient environment, while the sensor is in the known offset environment.

Abstract: An air/fuel ratio detector includes an exhaust diffusion chamber having one wall formed by an oxygen pump and another wall formed by an oxygen-concentration difference-actuated electrochemical cell that generates an oxygen differential signal corresponding to the difference in oxygen concentration between exhaust gas in the diffusion chamber and the ambient atmosphere. The differential signal is compared to a reference signal and the difference is used to control a current supplied to the oxygen pump in order to control the oxygen concentration in the exhaust gas. The current level is an indication of the existing air/fuel ratio.

Abstract: An electrochemical sensor capable of determining the partial pressure of various gases (e.g., CO, CO.sub.2, H.sub.2 S, alcohol vapors, hydrocarbons, NO.sub.x, etc.) and, optionally, substantially concurrently, but independently, oxygen content in gases and liquids. The sensor measures the amount of chemisorbent species formed either electrochemically by partial reduction (such as "Reduced-CO.sub.2 " in the case of CO.sub.2) or partial oxidation (in the case of alcohol) or non-electrochemically via specific adsorption (in the case of CO and hydrocarbons) on platinum or other metals. The charge required to oxidize this chemisorbed species is proportional to the amount of adsorbate on the electrode surface which is made a reproducible and reliable function of the partial pressure of the gas to be measured. By the proper selection of the sensor construction and electrical parameters, high sensitivity, fast response time, and high selectivity can be obtained.

Abstract: An air/fuel ratio detector providing an unambiguous output for both fuel-rich and fuel-lean regions is disclosed. The detector includes a solid-electrolyte oxygen-concentration-difference-actuated electrochemical cell sensor element and a solid-electrolyte oxygen pump element, each element being in the form of an oxygen-ion-conductive solid electrolyte having a porous electrode formed on both sides thereof. The electrochemical cell sensor element is disposed to face the pump element with a small gap therebetween. An air compartment open to the atmosphere is formed on the side of the pump element opposite the small gap.

Abstract: An apparatus for measuring ionic activity is comprised of a rotatable turret and at least one pair of vertically movable probes. The turret intermittently conveys slide-type ionic activity measuring devices, one by one, on each of which are spots of reference and sample solutions, to a measuring section where the probes come into contact with the measuring device so as to measure the potential difference corresponding to the difference in ionic activity of a specific ion between the reference and sample solutions. After measurement the turret further conveys the device to a discharging section where the device is automatically discharged.

Abstract: An apparatus for measuring ionic activity has a nozzle connected to a reservoir containing a reference solution. The reference solution is pumped up from the reservoir without coming into contact with air, so as to be quantitatively dripped through the nozzle when a slide-type ionic activity measuring device is located at a position below the nozzle. After the reference and sample solutions are spotted on the ionic activity measuring device, at least one pair of probes comes into contact with the device so as to measure potential difference corresponding to ionic activity difference of at least one ion between the reference and sample solutions.

Abstract: An air-to-fuel ratio detector for detecting the air-to-fuel ratio of the combustible mixture supplied to an engine on the basis of the concentration of oxygen gas in the exhaust gas of the engine, comprising an air-to-fuel ratio sensor provided to detect the oxygen gas concentration in the exhaust gas and consisting of an oxygen pump and an oxygen sensor which are disposed with a minute gap therebetween, and changeover means for simultaneously changing the direction of the pump current supplied to the oxygen pump and the polarity of the detection output signal given by the oxygen sensor; thereby capable of obtaining an air-to-fuel ratio detection signal when the operating air-to-fuel ratio is either in the rich air-to-fuel region or in the lean air-to-fuel region with respect to the stoichiometric air-to-fuel ratio.

Abstract: A coating composite provides extended corrosion resistance for substrate metals. The thin metallic undercoat of the composite contains combined metals. The heat curable and substantially resin free topcoat is established from composition containing chromium in non-elemental form, which topcoat composition may further contain particulate metal, all in liquid medium. In addition to outstanding corrosion resistance, the composite can retain substrate weldability and formability, while further enhancing paintability and weatherability.

Abstract: A metal composite is provided extended corrosion resistance. Prior to joining the metals of the composite, at least one of the metals is provided with a metallic undercoat. This undercoat is then coated with a metallic zinc layer. Lastly, a heat curable and substantially resin free topcoat is established on the zinc layer and cured. The topcoat composition contains chromium in non-elemental form and may further contain particulate metal, all in liquid medium. The metal composite is then formed by contacting metals including the thus coated metal. In addition to outstanding corrosion resistance, the composite can retain substrate weldability while further enhancing weatherability.

Abstract: The determination of the concentration of compounds such as CO.sub.2 having an influence on the pH of a medium during polarography is described. Characteristics of polarograms when obtained in unbuffered electrolytes (the polarogram plateau slope position of the upper knee and half-wave potential thereof) are pH-sensitive. These can be detected electronically and signals processed to provide a measure of such concentrations.In one preferred embodiment (FIG. 2) a miniature pO.sub.2 polarographic sensor has cathode channels (A) and (B) biased respecitvely at -750 mV and -950 mV. The output of channel (A) provides pO.sub.2 as in normal polarography. The output of (B) is divided (6) and further corrected for pO.sub.2 (8,10) to provide pCO.sub.2.The apparatus is especially useful for simultaneous pO.sub.2, pCO.sub.2 monitoring in physiological fluids without the need for a separate pCO.sub.2 sensor.