Patent ID: 9091658
Filing Date: 2015-07-28
Classification: G01N

Abstract:
1. A paramagnetic gas sensor apparatus, comprising: a body defining a chamber with at least one gas inlet and at least one gas outlet defining at least one gas flow pathway for allowing gas flow through the chamber; the at least one gas flow pathway having a first asymmetry that creates a first region of asymmetrical fluid flow; a set of magnets for creating a magnetic field within the chamber in a first direction; a test body; and a torsion balance for mounting the test body in said chamber, for rotation about an axis parallel to the direction of the magnetic field in response to a torque applied to the test body, which torque is generated in dependence on the magnetic susceptibility of a measurand gas; wherein the at least one gas inlet is arranged to supply gas to the chamber from positions at opposite sides of the chamber and in opposed directions, and at least one flow balance element provides a flow-modifying asymmetry in a gas flow pathway that creates a second region of asymmetrical fluid flow to mitigate a pressure imbalance in the vicinity of the test body that is caused by the first asymmetry.