Orbisphere Laboratories Neuchatel Sa

Orbisphere Corporation, Wilmington, Succursale De Collonge-bellerive

Orbisphere Laboratories, Inc.

Orbisphere Corporation Wilmington

Orbisphere Corporation

Orbishpere Laboratories Neuchatel Sa

John M Hale

Eugen Weber

Harry D Wright

Ion Bals

Jean-Paul Pellaux

Gerard R Stehle

Antoine Gagnebin

Francedillaois Gretillat

A photoacoustic device for analysis of fluids. The device is made up of (A) a source of a pulsating beam of light, preferably of the chopper type, and (B) an enclosure, preferably an elongated structure having a generally cylindrical, e.g. essentially tubular shape; and containing and holding--in sonic insulation--at least one reference chamber and at least one measuring chamber in an essentially linear or serial arrangement in a common cell within the enclosure, preferably in an essentially coaxial arrangement; the enclosure and the common cell provide a path P for the pulsating beam of light through the reference chamber and through the measuring chamber. For most purposes, it is preferred that the light beam pass first through the reference chamber and subsequently into the measuring chamber. Optionally, a second reference chamber is arranged at the end of the measuring chamber and a second measuring chamber may follow.

Photoacoustic analyzer and method

A membrane-enclosed sensor (1) of the type having a membrane (11) for exposure to a fluid external phase of analytical interest at an interface between the fluid external phase or sample, and said membrane; the sensor comprises a coiled, e.g. spiraloid, channel (15) at the interface; the channel has an inlet end (16) as well as an outlet end (18) for passing the external phase in contact with the membrane along said coiled channel which, preferably has a length which is at least about 5 times greater than the largest cross dimension of the membrane.

Membrane-enclosed sensor, flow control element and analytic method

An analytic device (1) for reflective luminoscopy comprises within an enclosure (11): a light source (12); a pair of spaced light detectors (141, 142); and a refractor body (16); the refractor body comprises a planar base (161), an entry plane (163) near the light source for light emanating therefrom, and an exit plane (165) near the spaced detectors for light that is being sensed by at least one of the detectors; the entry plane and the exit plane enclose an angle of less then 180.degree. and not less than 90.degree., the enclosure further includes a light-collimating means or lens (13) between the light source and the entry plane; a light-collecting means or lens (15) between the light detectors and said exit plane, and at least one light-reflecting surface (171) near the planar base (161); at least one luminoscopic layer (191) normally comprising a luminoscopic indicator and a thin transparent carrier, is arranged between the planar base and the at least one light-reflecting surface; the device includes both a luminoscopic reference as well as a measuring area for a luminoscopic reaction between a luminoscopic layer and a species of analytic interest.

Luminoscopic analytic device and method

A probe for measuring the concentration of an alcohol, such as ethanol, in a liquid, such as water. The probe according to the invention has a membrane that is permeable for vapors of the alcohol but substantially impermeable for the liquid; a measuring chamber having an open end closed against the liquid by the membrane is provided and has an inlet and an outlet; a pump or other pressure means serves to feed a purge gas, such as air, via the inlet into and out of the measuring chamber; a valve is provided near the inlet for controlled passage of the purge gas through the chamber; a suitably dimensioned detector including a pellistor or a gas-sensitive resistor is arranged in the measuring chamber for quantitative detection of the alcohol and for generating an electrical signal in proportion with the detection.

Probe and method for detecting alcohol

A method of determining a specific thermal conductivity parameter of a target gas having a known general thermal conductivity and being contained at a concentration of interest in a fluid medium (F) and comprising: contacting said fluid medium with an organic polymer membrane (11) provided at an interface between said fluid medium (F) and a sensing volume (12) containing a thermal conductivity sensor (13); the membrane (11) is substantially impermeable for any liquid components of the fluid medium (F) but has a known permeability for the target gas; the sensing volume (12) is periodically purged or flushed with a gas having a general thermal conductivity that differs from the thermal conductivity of the target gas; permeation of the target gas through the membrane (11) into the sensing volume (12) is permitted intermittently; at least one time-dependent parameter of the known general thermal conductivity of the target gas that has permeated into the sensing volume (12) is measured; and a parameter of analytical interest, e.g. a partial pressure of the target gas in the fluid (F), is calculated (14, 15) from the time-dependent value obtained and the predetermined permeability of membrane (11) for the target gas.

Method and apparatus for determining specific thermal conductivity

The concentration of a gas, such as carbon dioxide, in a fluid medium, such as an aqueous beverage, is monitored by pulsatingly measuring a specific parameter of diffusion of the gas through a membrane that is in contact with the fluid medium and is permeable for the gas but impermeable for the fluid; the gas is allowed to diffuse during a period of time into a receiving space of known volume; the amount of gas that diffuses into the receiving space is determined e.g. by measuring IR-absorption, heat conductivity, volume, pressure or the like physical parameters that depend upon the amount of gas in the volume; this yields a specific diffusion parameter or flux. The gas concentration of interest is then calculated from the specific parameter and a previously determined general parameter of diffusion of the gas through the membrane. Pulsating operation, i.e. a repeating sequence of cyclic removal and measuring phases, is characterized by relatively short phases; since, at the same time, the receiving space volume is relatively small while the gas permeability of the membrane is relatively low, reliable results can be obtained in quick response to concentration changes. The method can be applied for monitoring or for controlling the gas concentration by adding sufficient gas to maintain a desired gas concentration in the fluid medium.

Method and apparatus for monitoring gas concentrations

Quantitative determination of ozone contained in a fluid by an amperometric method comprises the steps of:

Ozone measuring method

A membrane-enclosed amperometric cell (MEAC) for use in determining the concentration of an electroactive species of interest (EASI) in an ambient medium comprises: a working electrode defined by a periphery; a liquid electrolyte covering the sensing area in a film of uniform thickness and being in electrolytic contact with a counter eletrode; a flexible polymer membrane of generally uniform thickness that is substantially impermeable to the electrolyte but permeable to the EASI; the membrane extends in a substantially conforming manner over the sensing area and the electrolyte film thereon; the cell of the invention has a physical permeation barrier that (1) consists of a layer of a substantially inert solid material which is substantially impermeable to the electrolyte and to the EASI; (2) extends between the ambient medium and the sensing area; (3) is disposed in a parallel configuration and in physical contact with the membrane; (4) has at least one opening permitting access of the EASI through the membrane to the sensing area yet phsyically restricting such access to a limited portion of the sensing area; (5) the limited portion is enclosed by a circumjacent margin that has an outer periphery defined by the periphery of the sensing area, an inner periphery, and a width defined by the smallest distance between the outer and the inner periphery; and (6) the width of the circumjacent margin is at least three times greater than the thickness of the electrolyte layer, or at least three times greater than the thickness of the membrane, depending upon the position of the barrier.

Amperometric cell

A method for determination of a first electroactive and normally gaseous species (EAGS) and a second EAGS in a fluid medium containing both EAGS; the medium is contacted with a first working electrode that is sensitive but to the first EAGS and generates a first amperometric signal that is indicative of the first EAGS concentration; the medium is also contacted with a second working electrode that is sensitive to both EAGS and produces a second amperometric signal that is indicative of the sum of both EAGS concentrations; the second EAGS concentration is calculated from the difference between the first and the second signal. For example, hydrogen can be measured in the presence of oxygen and this can be applied to monitor a fluid ambient or stream to prevent formation of explosive mixtures or corrosive conditions. An apparatus suitable for use in the method may comprise two separate MEACS each having a generally conventional structure, or may be in the form of a novel integrated cell structure including at least two sensing electrodes and at least one counter electrode. This provides for safe and simple monitoring under differing ambient conditions and without critical impact of operating parameters such as membrane thickness.

Amperometric method and apparatus

A method for determination of a first electroactive and normally gaseous species (EAGS) and a second EAGS in a fluid medium containing both EAGS; the medium is contacted with a first working electrode that is sensitive but to the first EAGS and generates a first amperometric signal that is indicative of the first EAGS concentration; the medium is also contacted with a second working electrode that is sensitive to both EAGS and produces a second amperometric signal that is indicative of the sum of both EAGS concentrations; the second EAGS concentration is calculated from the difference between the first and the second signal. For example, hydrogen can be measured in the presence of oxygen and this can be applied to monitor a fluid ambient or stream to prevent formation of explosive mixtures or corrosive conditions. An apparatus suitable for use in the method may comprise two separate MEACS each having a generally conventional structure, or may be in the form of a novel integrated cell structure including at least two sensing electrodes and at least one counter electrode. This provides for safe and simple monitoring under differing ambient conditions and without critical impact of oeprating parameters such as membrane thickness.

Amperometric method

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.

Thermal protection method for electroanalytical cell

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. A membrane-enclosed amperometric probe having an elongated body provided with a sensor face at one end of the body and with electrical electrode connections extending through the probe body; the body includes at least two elongated fluid-passing conduits which are not in fluid communication with the electrolyte space and which extend in axial direction through the body from a first region near the one body end to a second region near the other body end; the conduits have mutually communicating ends in the first region and separate fluid-feeding ends in the second region so as to permit passing a fluid through the probe body.

Thermal protection method for electroanalytical cell and amperometric

A method of and a sensor for quantitative electroanalytical determination of elemental hydrogen in a fluid medium are disclosed. A membrane enclosed amperometric cell is used that has at least two electrodes in contact with an aqueous electrolyte to provide a reaction impedance of the cell; the electrolyte is separated from the fluid medium by a membrane that is permeable to elemental hydrogen but substantially impermeable to the electrolyte and provides a membrane impedance of the cell; the electrodes include an anodic hydrogen sensing electrode and a cathodic counter electrode; the sensing electrode has a polished surface consisting of a platinum metal; further, the membrane is selected such that the membrane impedance exceeds the reaction impedance sufficiently to provide for membrane-controlled operation of the cell.

Electroanalytical method and sensor for hydrogen determination

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. A membrane-enclosed amperometric probe having an elongated body provided with a sensor face at one end of the body and with electrical electrode connections extending through the probe body; the body includes at least two elongated fluid-passing channels formed between a pair of coaxially arranged interfitting tubular members that extend in axial direction through the body from a first region near the one body end to a second region near the other body end; the channels have mutually communicating ends in the first region and separate fluid-feeding ends in the second region so as to permit passing a fluid through the probe body.

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Meinier, Switzerland

John M Hale