Abstract: Method for the protection and/or monitoring of a reference system with reference electrode in analytical measuring techniques, and reference system therefor, wherein an additional monitor electrode is provided for self-monitoring the outer bridge electrolyte (16) for contamination, the additional monitor electrode being arranged to permit measuring of the pH value (pX value) of the bridge electrolyte which is adjusted to the same pH value (pX value) as the reference electrolyte. A fault signal is released when a potential difference occurs between the additional electrode and the real reference electrode of the reference system. Further, the bridge electrolyte is preferably connected with the measured solution in pressure-balancing relationship via a flexible diaphragm arranged in the wall of the vessel containing the bridge electrolyte which diaphragm may also be designed to serve as mounting for the said first diaphragm.

Abstract: A galvanic electrode oxygen sensor which is useful in measuring transcutaneous oxygen pressure (pO.sub.2) contains a cathode in the form of a porous film of a metal below hydrogen in the Electromotive Series, an anode of a metal above hydrogen in the Electromotive Series, an electrolyte and an oxygen-permeable membrane in contact with the cathode and adapted to contact the skin of a patient. The sensor may also contain temperature measuring device or structure for compensating for temperature variations.

Abstract: A reference electrode for use in testing liquid at a high pressure, has an internal liquid containing body having an internal liquid containing space therein and a liquid-junction one side of which is exposed to the high pressure liquid to be tested and the other side of which is exposed to the internal liquid contained in the internal liquid containing space. A reference electrode body surrounds the internal liquid containing body and defines a pressure compensating space between the internal liquid containing body and the inside of the reference electrode body, the pressure compensating space being open outwardly of the reference electrode body at a part there of which is exposed to the high pressure liquid to be tested when the reference electrode is in position for normal use, the pressure compensating space receiving the high pressure liquid to be tested therein.

Abstract: A semiconductor integrated circuit for sensing a physico-chemical property of an ambient includes a pair of semiconductor devices (Q1, Q2) having a similar geometric and physical structure, one device (Q1) being sensitive to the property, the other being insensitive to the property, together with a differential amplifier (A1, A2, A3, A4, A5) having feedback connection to one of the pair of semiconductor devices.

Abstract: An apparatus for determining oxygen concentration in exhaust gases from an automotive engine is provided which includes a solid electrolytic member of oxygen ion conductive material disposed between a pair of first and second electrodes. In this apparatus, a porous insulating layer is formed on a cylindrical heater made of ceramics and a first electrode is formed on the outer periphery of the porous insulating layer. A solid electrolytic member is formed as a thin film form on the outer periphery of the first electrode layer and a second electrode is formed on the outer periphery of the solid electrolytic film member. Since the solid electrolytic film is formed such that it overlies the outer periphery of the cylindrical heater, it has an adequate structural strength even if formed to be a thinner film.

Abstract: An ion activity monitoring device is disclosed, having a semi-conductor device including an ion-sensitive field-effect transistor, for detecting the activity of ions in a liquid medium of interest, and a temperature sensor, for detecting the temperature of the liquid medium of interest, a constant current circuit for supplying a drain current of a particular value to the transistor, and a processing circuit for calculating the concentration of the ions in the liquid medium of interest. The drain current is of a value satisfying the relationship of .vertline.Id/.beta..vertline..ltoreq.0.10 volt.sup.2, wherein Id represents the drain current and .beta. represents the channel characteristic value of the ion-sensitive field-effect transistor. A method for operating the transistor is also disclosed.

Abstract: An electrochemical sensing element which includes at least one electrochemical cell having a planar solid electrolyte body and a pair of electrodes in contact with the planar solid electrolyte body, and which further includes at least one electrical heater layer which is located on one of opposite sides of the electrochemical cell. The heater layer comprises a heater member having a heat-generating portion in the form of a serpentine or sinuous strip to heat at least a portion of the electrochemical cell at which the electrodes are disposed. The serpentine strip is formed in zig-zag fashion to provide a heating region in which the heat-generating portion is accommodated. The heat-generating portion has a larger cross sectional area at its central parts located in a central portion of the heating region, than at its peripheral parts located adjacent to the periphery of the heating region.

Abstract: An oxygen sensor having increased stability in its sensitivity is provided. The oxygen sensor includes a sensing electrode spaced from a cadmium counter electrode. An alkaline electrolyte extends between the electrodes and permits the formation of cadmium hydroxide in the counter electrode as the cell is used. An electrical circuit connects the counter electrode and sensing electrode externally of the cell. The circuit includes a resistor and thermistor network and a voltmeter. Readings on the voltmeter can be calibrated to show the concentration of ambient oxygen diffusing a polymer membrane to the sensor electrode.

Abstract: This oxygen concentration detector employs an oxygen concentration sensor provided with a plate produced of a material which exhibits ionic conduction for oxygen (An oxygen ionic conductor), a cathode placed on the one surface of the oxygen ionic conductor plate, an anode placed on the other surface of the oxygen ionic conductor plate, and a porous material layer which functions to regulate the flow of oxygen which passes through the porous material layer to reach the cathode and the oxygen ionic conductor plate. The improvement realized in this oxygen concentration detector is to remove a drawback in which the output of this sensor makes an error depending on the temperature of a gas of which the oxygen concentration is measured.

Abstract: A rodlike ceramic member of a heater projects towards and into the active tip of the solid electrolyte tube of an oxygen sensor, extending out from the bottom end of the principal insulating member of the sensor which is made of the same ceramic material. Conducting paths of the heater are brought up to a shoulder where the wider insulating part joins with the carrier of the heater, for connection with conductors leading to the end of the main insulator which is remote from the measuring gas and, furthermore, on this shoulder, connections are also made between conducting paths of the solid electrolyte sensor probe and conductors leading to the end of the main insulator remote from the measuring gas. At that end of the main insulator, sleeve connections are made to connection wires for external connections.

Abstract: A combination pH/reference electrode is provided with the two electrochemical references being symetrically thermally insulated from the sensing membrane and being thermally adjacent each other. The portion of the pH fill buffer in contact with the inner surface of the sensing membrane is thermally insulated, as by KCl crystals, to rapidly equilibrate in temperatures with the sample solution.

Abstract: An oxygen probe for measuring the carbon potential of endothermic gas in a heat treating furnace. The probe uses a readily available, automative-type oxygen sensor having a solid electrolyte element. The sensor is mounted on a heat conducting base plate. The sensor element is surrounded by a gas flow tube extending from the base plate. Exit ports around the base of the sensor element extend through the base plate and into the area defined by the gas flow tube causing an axial, radially symmetric flow of gas around the sensor element. The tip of the element is heated above the temperature of the gas while the base of the element is conductively cooled by the base plate. A temperature gradient is thus caused along the length of the sensor element, increasing its sensitivity.

Abstract: A limiting electric current type oxygen sensor comprising a first electrode of a gas-permeable film, a thin solid electrolyte film which is crystallized along one direction to decrease resistance and which has a thickness falling in the range between 0.1 .mu.m and 30 .mu.m, and a second electrode of a gas-permeable film sequentially formed on an electrically insulating substrate. This limiting electric current type oxygen sensor is also provided with a porous coating layer or a dense coating layer. The porous coating layer made of Al.sub.2 O.sub.3, SiO.sub.2, spinnel, SiC, Si.sub.3 N.sub.4 and etc., has a porosity of not more than 30% and a thickness of not less than 1 .mu.m, and serves as a gas diffusion flow rate-determining portion. The dense coating layer serves to control a gas permeation path such that either the first electrode or the substrate is used as the gas diffusion flow rate-determining portion.

Abstract: A method of thermal protection of a membrane-enclosed amperometric cell of the type comprising an electrolyte within an electrolyte space containing electrodes and enclosed by a semi-permeable membrane which defines a sensor face; heat exchange within said cell is effected for controlled heat compensation of the electrolyte when the sensor face is exposed to temperatures outside of the operative temperature range of the cell.

Abstract: Two dissolved gas components in sample water, for example, oxygen and hydrogen in core water, are readily quantitatively determined in one and same membrane-type oxygen meter by using a membrane producing an overlapped potential region where a potential region for an oxidation limiting current plateau is overlapped with that for a reduction limiting current plateau between two dissolved gas components, and applying to between a pair of an electrode and a counter-electrode a more positive potential than the equilibrium potential for oxidation-reduction reaction of one of the two dissolved gas components principally, thereby measuring a current generated between the electrodes, and a more negative potential than the equilibrium potential for oxidation-reduction reaction of the other dissolved gas component, when desired, thereby measuring a current generated between the electrodes, and quantitatively determining a concentration of the first dissolved gas component from the latter current quantity and quantitati

Abstract: An oxygen concentration detector under a temperature control for an internal combustion engine. An oxygen sensor of a critical current type is held between a gas under test and a reference gas, in the vicinity of which a heater is located for heating up the oxygen sensor in a sensor activating temperature range. A first voltage is applied for a positive bias control to the oxygen sensor during a first period, and a second voltage is applied for a negative bias control thereto during a second period. Electric current flowing through the oxygen sensor is detected during the first period in order to detect the oxygen concentration in the gas under test. The current value is also detected during the second period in order to detect and maintain constant the internal electric resistance of the oxygen sensor by controlling the heater heating output.

Abstract: In accordance with the principles for transcutaneous measurement of a blood parameter, such as the partial pressure of a blood gas, an electrochemical measuring electrode device (1) is applied to the skin surface (2) of a person. The electrode device has a body (10), e.g. a thick film substrate, which is thermostated to a predetermined temperature and, furthermore, includes a sensor (11) together with a membrane (14) confining an electrolyte solution within an electrolyte reservoir (15). Furthermore, the electrode device includes a jacket having an annular metallic body (16), a metallic body (4) and a thick film substrate (8), which is thermostated to the same temperature as the body (10) of the electrode device.

Abstract: A method of thermal protection of a membrane-enclosed amperometric cell of the type comprising an electrolyte within an electrolyte space containing electrodes and enclosed by a semipermeable membrane which defines a sensor face; heat exchange within said cell is effected for controlled heat compensation of the electrolyte when the sensor face is exposed to temperatures outside of the operative temperature range of the cell.

Abstract: The invention provides a limiting electric current type oxygen sensor with a microheater, having: an oxygen ionic conductor; an anode and a cathode respectively formed on two major surfaces of the oxygen ionic conductor; an insulating film which has a porosity of not less than 0.2 [%], an average pore diameter of not less than 140 [.ANG.], and a thickness between 0.2 [.mu.m] and 10 [.mu.m], and which is formed on one of the anode and the cathode so as to regulate a flow rate of oxygen gas and to provide electrical insulation; and the microheater formed on the insulating film. The oxygen ionic conductor is electrically insulated from the microheater through the insulating film. The invention also provides a limiting electric current type oxygen concentration detecting device having the limiting electric current type oxygen sensor and a constant temperature control circuit.

Abstract: A heater-incorporating oxygen sensor includes a solid electrolyte oxygen sensor element comprising a solid electrolyte provided with electrodes on both its sides and a heater, said heater being a ceramic heater formed by sintering and embedding a metallized pattern in a ceramic insulator as one solid body, said ceramic heater being disposed within a space surrounded with said oxygen sensor element.

Abstract: A sensor which has an insulating substrate on which is formed a heater layer for heating the sensor on a part thereof and which is operated above a predetermined temperature. The heater layer is made of a material which has a thickness of 0.2 .mu.m to 20 .mu.m and which is made of platinum, rhodium, palladium or a mixture thereof. The insulating substrate is made of alumina, quartz, spinel, magnesia, zirconia, or mixtures thereof. A heater protective layer having a thickness of 0.01 .mu.m to 500 .mu.m is made of materials based on alumina, silica, spinel, magnesia, zirconia or mixtures thereof.

Abstract: A potentiometric electrode having an ion selective half cell containing a non-reactive lead such as platinum in contact with an electrolyte containing a reversible redox couple having a large exchange current and a substantially flat temperature coefficient of potential such as 5 molar iodide, 3.times.10.sup.-2 molar triiodide, thereby having an electrode with a rapid and reproducible temperature response.

Abstract: A galvanic cell type oxygen sensor comprising a galvanic cell comprised of a cathode made up of metal effective for the electrolytic reduction of oxygen, an anode made up of lead material and an electrolyte made up of an aqueous mixed solution of organic acid and organic acid salt, which has a long life and a high output voltage, is not at all affected by carbon dioxide and which can prevent the generation of hydrogen from the cathode, is disclosed.

Abstract: A pH electrode which is capable of withstanding repeated exposures to sterilizing temperatures. An electrode body having a pH sensing member is at least partially filled with a bed of electrochemically inert particles. After an internal reference is inserted into the particle bed, the bed is injected with a quantity of electrolyte which is sufficient to establish continuity between the sensing member and the internal reference, but which is not sufficient to produce destructive internal pressures when the electrode is subjected to sterilizing temperatures. The electrode is completed by forming a seal between the electrode body and the internal reference.

Abstract: An oxygen concentration detector provided with an oxygen concentration sensor further provided with an oxygen ionic conductor, a cathode placed on one surface of the oxygen ionic conductor, an anode placed on the other surface of the oxygen ionic conductor, and a layer convering the cathode for regulating the diffusion of oxygen gas toward the cathode. Temperature compensation is applied to the output of the detector which is inherently influenced by the temperature of the sensor. More specifically, an oxygen concentration detector is provided with the foregoing oxygen concentration sensor, and voltage or current is alternatively supplied to the sensor to measure a limiting current of the sensor and internal resistance of the sensor, and the current or the voltage produced by the foregoing application of voltage or current, and a temperature compensation is applied to the detected magnitude of limiting current according to the internal resistance of the sensor.

Abstract: A temperature control system is disclosed wherein a heater of a gas sensor and a plurality of reference resistors cooperate to form a bridge circuit. The temperature control system comprises a comparator means for monitoring a balancing voltage of the bridge circuit and generating a control signal indicative of the balancing voltage and an electric power amplifier means responsive to the control signal for varying a voltage applied to the bridge circuit in such a manner to reduce the balancing voltage. The gas sensor has mounted therein at least one of the plurality of reference resistors, which reference resistor having a resistance resulting from multiplying the resistance of the heater with a constant.

Abstract: A gauge measuring percent oxygen by simultaneously measuring oxygen partial pressure and ambient atmospheric pressure with solid state transducers. Two electrical signals obtained from the transducers are combined in a summing amplifier in accord with an empirically determined relation to yield a percent oxygen value which is displayed. The gauge has provisions for using an internal oxygen partial pressure transducer or an external probe connected to the gauge by a cable.

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.

Abstract: An improved oxygen sensing cell, especially of the polarographic type, is intended for use primarily in a gaseous environment. The cell has a cathode located at the bottom of the cell body. The cathode comprises a gold mesh electrode laminated to a thin-film sense membrane. The electrode is thus made immobile relative to the membrane, thereby improving the response time and providing for long-term sensor stability. The cell further has a guard electrode for the cathode. The guard electrode operates continuously and scavenges any oxygen molecules which are dissolved in the electrolyte and diffused towards the cathode. As a result, the dynamic range of the cell is substantially increased. The anode comprises a silver wire wound about a spool retained within the main cavity in the cell body. A p.c. board, as well as a compensation membrane, are resiliently retained at the top of the cell body. The body carries conductors for electrically connecting the p.c.

Abstract: Disclosed herein is a physiological, electrically heated, thermostatically controlled sensing unit of the type used in the medical field for measuring blood contents, such as oxygen. A typical unit comprises a housing for application to the skin of a living being, an electric heater element within the housing, and a temperature-responsive switching circuit, also accommodated within the housing. The switching circuit automatically disconnects a power supply to the heater element when the skin temperature exceeds an adjustable predetermined threshold level. The power supply for the switching circuit is directly connected to the power supply for the heater element within the housing.

Abstract: In an instrument with a sensor for gas analysis which, based on the principle underlying its measurement, indicates the partial pressure of the gas constituent to be measured, the indication of the change in the partial pressure of the gas constituent is affected by changes in the atmospheric pressure. Such instruments must be calibrated at mean sea level and adjusted for changes in height at the measuring site.In order to eliminate the need for adjustment or recalibration, there is included in the instrument a pressure-sensitive module to compensate for the effects of the atmospheric pressure on the sensor. The module compensates the measured value directly or by means of a microprocessor with regard to the prevailing pressure conditions.

Abstract: To provide for temperature measurement of a solid electrolyte polarographic gas composition sensor, an ac signal is superimposed from an ac voltage source (2) on the applied voltage from a voltage source (1) if the sensor is a polarographic sensor, the ac signal being separated from the output by a filter combination (6, 7), the dc output being evaluated as usual, and the ac output being rectified in a rectifier (9) to obtain a measure of the temperature since the ac resistance (R.sub.alt) is highly temperature dependent (see FIG. 3). The ac preferably is about 10% of the applied dc voltage, so that the voltage swing of the ac potential falls well within the linear range of output current with respect to voltage (see FIG. 2). The output from the ac channel (7, 9) to evaluate the temperature signal can be connected to a control loop circuit (10, 11), including a heater (11) to heat the sensor to maintain a uniform temperature thereof.

Abstract: A device for use in exhaust gases of internal combustion engines to detect changes in air/fuel ratio. The device has a body of a transition metal oxide, such as TiO.sub.2, with a first pair of electrodes attached thereto to measure a change in the resistance of the transition metal oxide in response to a change in the air/fuel ratio. The device includes a combination of a porous layer of an oxygen ion conductive solid electrolyte such as ZrO.sub.2 arranged such that the exhaust gas comes into contact with the transition metal oxide body always by diffusion through the solid electrolyte layer and a second pair of electrodes arranged so as to force a DC current to flow in the solid electrolyte from selected one of these electrodes to the other.

Abstract: A multifunctional, low mass reference electrode of a nickel tube, thermocouple means inside the nickel tube electrically insulated therefrom for measuring the temperature thereof, a housing surrounding the nickel tube, an electrolyte having a fixed sulfide ion activity between the housing and the outer surface of the nickel tube forming the nickel/nickel sulfide/sulfide half-cell. An ion diffusion barrier is associated with the housing in contact with the electrolyte. Also disclosed is a cell using the reference electrode to measure characteristics of a working electrode.

Abstract: A gas sensor cell assembly has planar electrodes separated by a planar hydrophilic wick which extends through the electrode into an electrolyte expansion chamber where it contacts an electrolyte. The cell is extremely compact and operates in all orientations.

Abstract: Determining the oxygen content in gases, particularly combustion exhaust gases, uninfluenced by temperature variations of the gases by passing the gases into a first electrical measuring cell having a solid electrolyte and electrodes connected to a current source. A diffusion-limited electric current flow dependent on the oxygen content of the gases is obtained and measured as a first electrical signal. Passing an auxiliary gas with constant oxygen content into a second measuring cell similar to the first cell and under the same conditions and obtaining a second electrical signal. The quotient of the two electrical signals is a measure of the oxygen content of the gases uninfluenced by temperature variations of the gases.

Abstract: To render output of a polarographic sensor essentially independent of aging of electrodes and temperature effects of the solid electrolyte body, within the operating ranges of the sensor to measure the oxygen composition of exhaust gases, the solid electrolyte plate of, for example, 50 mm length, 8 mm width and 1 mm thickness has a sensing electrode system including a cathode (2), and an anode (3) applied thereto, connected to a voltage source (7) of controllable output voltage. An oxygen molecule diffusion barrier (6) is applied to the cathode electrode. Additionally, a further electrode pair (5,4) is applied to the solid electrolyte body (1), serially connected in the current limiting circuit including the control voltage source.