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:
Nov. 11, 1997
Filed:
Aug. 09, 1995
Applicant:
Inventors:
Shigeru Hagiwara, Kawasaki, JP;
Noriaki Tokuda, Kawasaki, JP;
Assignee:
Nikon Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B01D / ;
U.S. Cl.
CPC ...
96117 ; 96134 ; 96142 ; 55274 ;
Abstract
A chemical filter for removing a chemical impurity is arranged at an air inlet, and a gas sensor for adsorbing the chemical impurity is arranged upstream of the chemical filter. The service life of the chemical filter is determined on the basis of the resonance frequency of the gas sensor. Alternatively, the chemical filter has a specific portion whose removal capacity for the chemical impurity is lower than that of the rest, and a sensor for sensing the chemical impurity is arranged downstream of the specific portion. The service life of the chemical filter is predicted on the basis of an output from the sensor.