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:
Jan. 14, 1992
Filed:
Dec. 27, 1990
Applicant:
Inventor:
Charles D O'Neal, III, Bolton, MA (US);
Assignee:
The BOC Group, Inc., Murray Hill, NJ (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
G01L / ;
U.S. Cl.
CPC ...
73755 ; 73708 ; 330789 ; 338 36 ;
Abstract
The present invention provides a vacuum gauge having two integrated circuits connected in a half bridge circuit to register subatmospheric gas pressure from a change in thermal gas conductivity. One of the integrated circuits serves to generate an electrical current proportional to the ambient temperature and a function of its power output conducted by the gas. The other of the integrated circuits acts as a reference to generate an electrical current proportional to ambient temperature. The half bridge circuit acts to subtract the currents so that subatmospheric pressure can be read on an ammeter as a function of gas thermal conductivity.