Ex parte LACOUNT - Page 11

                Appeal No. 97-1107                                                                                    Page 11                   
                Application No. 08/047,512                                                                                                      

                         We conclude that the examiner has established a prima facie case of obviousness with respect                           

                to the subject matter of claims 10, 15-21, 23, 25 and 26, which has not been sufficiently rebutted by                           


                Obviousness of Claim 27                                                                                                         

                         Claim 27 requires that the gas analysis cell have an internal tube fixed to the inlet that extends                     

                into the cell body.  As Barnes does not teach an internal tube at the inlet, the examiner has rejected                          

                claim 27 over Barnes in combination with Rossiter, optionally Lew and additionally Nelson.  As pointed                          

                out by the examiner in the rejection (Answer, page 7), Nelson teaches a gas inlet 87 that extends into                          

                the cell body.  The extended inlet 87 is positioned to direct the gas in a manner that results in a                             

                reduction in the time required to achieve gas purge.  We note that the gas cell body is designed to                             

                conform to a conical optical beam.  We agree with the examiner that it would have been obvious to one                           

                of ordinary skill in the art at the time of the invention to provide the cell of Barnes with a tube extending                   

                into the cell interior as taught by Nelson so that the gas could be admitted at a tangent and thus the gas                      

                purging time could be reduced.                                                                                                  

                         The fact that Nelson teaches a conical cell and admitting the gas at the diverging end and                             

                purging the gas at the converging end does not teach away from using an extending inlet in Barnes to                            

                create a flow of gas that results in faster purge.  One of ordinary skill in the art would have reasonably                      

                expected that gas flow would have improved at least up to the necked down area of a converging-                                 

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