Shielded resistor

Claim 1

IN A GAS ANALYSIS THERMAL CONDUCTIVITY CELL, A SHIELDED RESISTOR COMPRISING IN COMBINATION AN ANALYTICAL ELEMENT DISPOSED GENERALLY TRANSVERSE THE DIRECTION OF SAMPLE GAS FLOW DISPLAYING A VARIATION IN ELECTRICAL RESISTIVITY AS A FUNCTION OF THE THERMAL CONDUCTIVITY OF A SURROUNDING SAMPLE GAS PROVIDED WITH A PRIMARY SOLID GAS FLOW BARRIER ENCLOSING THE ANALYTICAL ELEMENT OVER ITS FULL LENGTH AND CIRCUMFERENCE BUT OUT OF PHYSICAL CONTACT THEREWITH AND A SECONDARY SOLID GAS FLOW BARRIER DISPOSED ADJACENT TO AND UPSTREAM IN THE DIRECTION OF SAMPLE GAS FLOW FROM SAID PRIMARY GAS FLOW BARRIER, SAID SECONDARY GAS FLOW BARRIER EXTENDING AT LEAST THROUGHOUT THE FULL WIDTH AND LENGTH OF SAID PRIMARY GAS FLOW BARRIER MEASURED GENERALLY TRANSVERSE THE DIRECTION OF SAMPLE GAS FLOW, BOTH SAID PRIMARY AND SAID SECONDARY GAS FLOW BARRIES BEING PROVIDED WITH PERFORATIONS SMALL ENOUGH IN SIZE TO SUBSTANTIALLY PREVENT FLOW OF GAS THERETHROUGH UNDER THE EXISTING GAS PRESSURE DIFFERENTIAL BUT LARGE ENOUGH AND OF SUFFICIENT TOTAL FREE AREA TO PERMIT SUBSTANTIALLY UNIMPEDED DIFFUSIONAL PASSAGE OF GAS SAMPLE THERETHROUGH TO THE ANALYTICAL ELEMENT, THE RADIAL SPACING BETWEEN SAID ANALYTICAL ELEMENT AND SAID PRIMARY GAS FLOW BARRIER BEING PRESELECTED TO A CLEARANCE SUFFICIENTLY SMALL TO SUBSTANTIALLY COMPLETELY PREVENT MOVEMENT OF GAS BY THERMAL CONVECTION WITHIN THE INTERSPACE BETWEEN SAID ANALYTICAL ELEMENT AND SAID PRIMARY GAS FLOW BARRIER.