Patents Assigned to Alphasense Limited
  • Patent number: 8193502
    Abstract: An optical absorption gas sensor comprising a body having an internal wall which defines a chamber, at least one aperture in the body through which a gas sample can enter the chamber, a light source, at least one reflector, a detector assembly which extends into the chamber and has a first side and an opposite second side, a detector which measures light which is incident at least a range of angles on at least a part of a first surface of the detector assembly on the first side of the detector assembly, wherein the light source is located within the chamber on the second side of the detector assembly, the whole being configured such that light from the light source passes through the gas sample and is reflected around the detector assembly, by the at least one reflector, onto the detector.
    Type: Grant
    Filed: March 21, 2008
    Date of Patent: June 5, 2012
    Assignee: Alphasense Limited
    Inventors: Elizabeth Jane Hodgkinson, John Robert Saffell, Richard Smith
  • Patent number: 7651597
    Abstract: A dual gas sensor is described, having first and second working electrodes separated by a gas impermeable portion. The electrodes are preferably located on a gas permeable polymer support, with the gas impermeable portion being formed by compression of the permeable support. The sensor may also include one or more filters for location adjacent the electrodes to filter certain gases from the air. The preferred sensor is able to detect carbon monoxide and hydrogen sulfide. The sensor housing is formed with four connection pins, allowing a standard sensor housing to be used for dual sensors as well as single sensors having a dummy pin.
    Type: Grant
    Filed: December 15, 2004
    Date of Patent: January 26, 2010
    Assignee: Alphasense Limited
    Inventors: John R. Saffell, Richard Smith, Darry H. Dawson
  • Publication number: 20080239322
    Abstract: An optical absorption gas sensor comprising a body having an internal wall which defines a chamber, at least one aperture in the body through which a gas sample can enter the chamber, a light source, at least one reflector, a detector assembly which extends into the chamber and has a first side and an opposite second side, a detector which measures light which is incident at at least a range of angles on at least a part of a first surface of the detector assembly on the first side of the detector assembly, wherein the light source is located within the chamber on the second side of the detector assembly, the whole being configured such that light from the light source passes through the gas sample and is reflected around the detector assembly, by the at least one reflector, onto the detector.
    Type: Application
    Filed: March 21, 2008
    Publication date: October 2, 2008
    Applicant: Alphasense Limited
    Inventors: Elizabeth Jane HODGKINSON, John Robert Saffell, Richard Smith
  • Patent number: 7179355
    Abstract: Disclosed is an electrochemical sensor for measuring carbon monoxide in a gas sample, the sensor comprising a working electrode including a working electrode catalyst, and a diffusion restriction means for restricting the diffusion of the gas sample to the working electrode; wherein the working electrode catalyst comprises oxidised platinum having a hydrogen cross-sensitivity of less than 10% and being present in an amount such that the activity capacity is at least 5.
    Type: Grant
    Filed: February 19, 2003
    Date of Patent: February 20, 2007
    Assignee: Alphasense Limited
    Inventor: John Christopher Harper
  • Publication number: 20050145493
    Abstract: A dual gas sensor is described, having first and second working electrodes separated by a gas impermeable portion. The electrodes are preferably located on a gas permeable polymer support, with the gas impermeable portion being formed by compression of the permeable support. The sensor may also include one or more filters for location adjacent the electrodes to filter certain gases from the air. The preferred sensor is able to detect carbon monoxide and hydrogen sulfide. The sensor housing is formed with four connection pins, allowing a standard sensor housing to be used for dual sensors as well as single sensors having a dummy pin.
    Type: Application
    Filed: December 15, 2004
    Publication date: July 7, 2005
    Applicant: Alphasense Limited
    Inventors: John Saffell, Richard Smith, Darry Dawson
  • Patent number: 6746587
    Abstract: An electrochemical gas sensor comprises: a working electrode for exposure to a gas to be sensed; a counter electrode having an outer periphery; a reservoir for electrolyte; wick means providing a path for electrolyte to pass from the reservoir, around a first part or parts of the outer periphery of the counter electrode to provide electrolytic continuity between the counter electrode and the working electrode; and a gas diffusion means providing a path for gas to diffuse to or from a second part or parts of the outer periphery of the counter electrode.
    Type: Grant
    Filed: November 15, 2001
    Date of Patent: June 8, 2004
    Assignee: Alphasense Limited
    Inventors: John R. Saffell, Darryl H. Dawson
  • Patent number: 6623619
    Abstract: Electrochemical sensor for determining analyte in the presence of interferent, particularly carbon monoxide in the presence of hydrogen. An electrochemical cell is designed so that current flow resulting from reference electrode potential shift caused by interferent cancels out the current flow caused by interferent at the working electrode. Another electrochemical cell corrects for interferent concentration using the potential difference between a reference electrode in contact with interferent and a referent electrode not affected by inteferent.
    Type: Grant
    Filed: May 14, 2001
    Date of Patent: September 23, 2003
    Assignee: Alphasense Limited
    Inventors: John R Saffell, Michael L Hitchman, Darryl H Dawson
  • Patent number: 6365022
    Abstract: A gas sensor comprising an electrolytic cell having detecting and reference electrodes connected by a solid electrolyte. In a first embodiment, both electrodes comprise Ag2CO3 and Ag4RbI5, and the electrolyte is Ag4RbI5, the reference electrode being in contact with a reference gas. In a second embodiment, the reference electrode is a silver electrode and no reference gas is needed. The sensor is operable at room temperature to measure CO2 concentrations, and is relatively unaffected by water vapor.
    Type: Grant
    Filed: March 17, 2000
    Date of Patent: April 2, 2002
    Assignee: Alphasense Limited
    Inventors: Michael L. Hitchman, Migeun Park