Catalyst Research Corporation

Mine Safety Appliances Company

Alan A Schneider

Joseph D Jolson

RaeAnn M Auel

Towner Bennett Scheffler

David A Stewart

John F Price

Brian Keith Davis

Harshad Tataria

George C Bowser

Stephen E Long

Daniel E Bruce

David N Kramer

Matthew O'Boyle

George C Bowser, Jr

Ross E Magladry

Ronald J Flower

Roberta A Herman

Lurman H Foxwell

Darla J Schrodt

William A Travers, Jr

Lee E Martin

Govind R Gadwal

Lewis C Kenyon

James R Hetmanski

Barbara C Miller

The present invention provides an electrochemical sensor for the detection of an analyte, wherein the output or response of the electrochemical sensor approximates the dose-response behavior of a living organism upon exposure to the analyte. The electrochemical sensor comprises a housing including an inlet port therein to allow the analyte to enter the housing. The electrochemical sensor further comprises at least a first electrode and a second electrode within the housing. Electrical conductivity is maintained between the first electrode and the second electrode via an electrolyte system present within the housing. The electrochemical sensor further comprises a resistor in series electrical connection with the first electrode and the second electrode. This resistor has a resistance adapted to be sufficiently high such that the output of the electrochemical sensor over time at a particular concentration of the analyte approximates the response of a living organism to the analyte over time at that particular concentration. The present invention also provides a method of using an electrochemical sensor as describe above.

Electrochemical sensor approximating dose-response behavior and method

The present invention provides a low-cost alternative to currently available electrochemical sensors. In general, the present invention provides an electrochemical sensor for the detection of an analyte comprising a first metallic housing member and a second metallic housing member. The first metallic housing member and the second metallic housing member are brought together in sealed connection to create a sealed enclosure therebetween. Contained within the enclosure are a first electrode, at which the analyte reacts, and a second electrode, at which a reaction complimentary to the reaction of the analyte at the first electrode takes place. An acidic electrolyte is also contained within the enclosure of the first metallic housing member and the second metallic housing member.

Electrochemical sensor

A gas detection device is provided comprising an exterior housing in which an active pelement and a compensating pelement are disposed. The gas detection device further comprises a porous frit seated within a distal end of the exterior housing to separate the active pelement and the compensating pelement from the surrounding environment. The porous frit is adapted to prevent flashback into the surrounding environment while allowing movement of environmental gas through the porous frit to contact the active pelement and the compensating pelement. The gas detection device further comprises a flow guide for directing flow of environmental gas into the gas detection device disposed adjacent the exterior side of the porous frit. The flow guide comprises an inlet port through which a forced flow of environmental gas is pumped to pass through the porous frit and into the exterior housing in a direction generally parallel to the axis of the exterior housing. The flow guide also comprises an outlet port through which gas may exit the exterior housing. A gas detection device is also provided in which the electrical resistance of the compensating pelement is measured to determine concentration of combustible gas at combustible gas concentration levels above a predetermined concentration level set equal to the LEL (Lower Explosive Limit). The gas detection comprises a circuit for reducing current passing through the active pelement when the gas detection device is being used above the predetermined concentration level.

Device for detecting gases for use in diffusion and forced flow modes

A simple potentiostat circuit for use in biasing a three-electrode electrochemical cell is described wherein a direct electrical connection is made between the sensing electrode and the reference electrode during normal operation of the cell. Preferably the electrical connection is a resistor. By selecting the resistive value properly, the zero gas current of the cell is eliminated without negatively affecting the response of the cell.

Potentiostat circuit for electrochemical cells

A compact electrochemical gas sensor for detecting toxic gases is described which utilizes a fluted electrically-conducting feedthrough for making the electrical connection from outside the sensor with each electrode inside the sensor. Utilization of the fluted electrically-conducting feedthroughs significantly reduces the number of parts needed to make the sensor as well as reduces the likelihood of electrolyte leakage from the sensor. Additionally, the electrochemical toxic gas sensor may use a gas permeable membrane instead of a gas porous membrane.

Electrochemical toxic gas sensor

An improved lithium-iodine battery is resistant to failure caused by iodine vapor within the battery. The entire interface of the current collector with the lithium anode is isolated from other battery components by a rigid, electrical-insulating sleeve.

Lithium-iodine battery

The present invention is for an electrochemical cell and method for quantitatively detecting noxious gas which comprises a first working electrode comprising a gas diffusion membrane having bonded thereto a catalytic portion electrochemically reactive with the noxious gas; a second working electrode having electrochemical activity with the oxidation/reduction products produced at the first working electrode; a counter electrode; a reference electrode; an electrolyte; means for containing said electrolyte and said electrodes; means for maintaining a fixed potential on said first working electrode relative to said reference electrode of from about 1.0 to 1.8 volts with respect to the potential of the reversible hydrogen couple of the electrolyte of the cell; and means for maintaining a fixed potential on said second working electrode relative to said reference electrode of from about 1.0 to 2.2 volts with respect to the potential of the reversible hydrogen couple of the electrolyte of the cell, the fixed potential on said working electrode being maintained at a voltage higher than the fixed potential being maintained on said first working electrode.

Electrochemical cell

Method for the detection of noxious gases

Electrochemical sensor cells having reduced zero current temperature sensitivity comprise a working electrode and a counter electrode in close proximity and in contact with an electrolyte. Both electrodes are exposed to the atmosphere to be tested and at least a portion of the counter electrode is masked from the electrochemically active gas in the atmosphere.

Electrochemical gas sensor

Electrochemical cell for the detection of noxious gases

A multi-wire telephone system which facilitates voice and data communication between any two telephones connected to each other with one of a plurality of standard shielded twisted-pair cables. The telephones, which are battery-powered, feature standard telephone operation without a central switching and control station or PBX. Each telephone is provided with a microprocessor which can generate and decode all signals necessary to establish communication with any other telephone in the system. Since a PBX is not required, a break in any phone line will result in two systems operating independently of each other although somewhat degraded performance can be expected, depending upon the nature of the break. Whenever communication is established between two stations in the system, a direct current bias is impressed on the cable interconnecting those stations such that all other stations in the system can determine that that particular cable is in use and can select another cable for communication. Communication is initially established between stations with the use of frequency shift keyed signals sent from one station and retransmitted from the called station before voice communication is established. The telephone system has both private and page communication capabilities and can transmit data in the form of pulsed signals as well as voice signals. The system incorporates a main dispatcher station which can interrupt any private communication in emergency situations and for data transmission.

Telephone communication system

A telephone system is provided which requires no central office. All the stations on the system are interconnected by a single line or cable and each station includes a computer which carries out the necessary switching. Each station is then able to call any other station, or to respond to a call, without requiring any central office. Frequency division multiplexing is used to permit a number of conversations to be carried on simultaneously and two frequencies are assigned to each conversation to permit duplex operation. A page capability is also provided.

Telephone system in which communication between stations is controlled

The present invention provides a means for compensating for temperature induced variations in the span and zero signals of an electrochemical detector. The invention comprises a first compensating circuit electrically connected to the output of the detector and includes a first thermistor and a first amplifier which compensate for all variations in the span signal as well as some variation in the zero signal. A second compensating circuit comprising a second thermistor and a power source and voltage divider network electrically connected to the second thermistor for adjusting zero current wherein the output of the second thermistor is algebraically added to the output of the first compensating circuit by a second amplifier connected to the outputs of the first and second circuit and includes a resistance feedback loop to the output of the second thermistor.

Thermal composition circuit for electrochemical detectors

A lithium halide battery appropriate for low-cost, mass production is disclosed in which the battery comprises an outer encasement member having top and bottom portions and an opening through one with at least one pelletized depolarizer positioned within the encasement member and in electrical contact therewith. The battery includes a lithium anode in contact with the depolarizer but electrically separated from the encasement member. At least one insulator means is positioned in contact with the anode and includes an opening therethrough located to align with the opening in the encasement. A terminal pin is positioned through the opening in the encasement member, but insulated from the periphery thereof, and in electrical contact with the anode through the opening in the insulator means.

Lithium halide battery

The present invention relates to a solvator plug for replenishing aqueous or non-aqueous solvents in devices such as electrochemical sensor cells. The plug includes a housing adapted to communicatingly mount to a cell or the like which houses a selected solvent for absorption by the cell. The solvent is maintained within the housing by means of an absorbant material or membrane and is delivered by virtue of osmotic pressure differences.

Growing community of inventors

Reisterstown, MD, United States of America

Alan A Schneider