The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 01, 1997
Filed:
Mar. 20, 1995
Derek Stuart, Sheppfield, GB;
Land Instruments International Limited, Dronfield, GB;
Abstract
The invention relates to apparatus for open-path gas monitoring and is particularly concerned with measuring the opacity of stack gases. Single and double pass systems to provide an optical across the stack, are known, but to provide meaningful data, gain compensation is required to deal with temperature variations and the possibility of ageing of electronic components. The object of the present invention is to provide an instrument that meets the above requirement but without moving components, which objective is met by a construction comprising a transceiver unit adapted to be mounted on one side of the optical path; a passive reflector adapted to be mounted on the other side of the path; and electronic control circuitry, the transceiver unit comprising: