Apparatus for measuring the differences in magnetic susceptibilities of gases

Claim 1

Apparatus for measuring the difference in magnetic susceptibility of a sample gas and of a reference gas, the reference gas having particular, constant susceptibility, comprising: magnet means defining a magnetic circuit and having pole shoe means establishing at least one measuring gap traversed by a magnetic field produced by the magnet means, there being a plane or line of symmetry bisecting said pole shoe means and said gap between said pole shoe means so that the magnetic field in the gap is symetrical with respect to said plane or line of symetry and having zones of homogeneity and inhomogeneity on both sides of said plane or line of symmetry; a test body including two chambers of symmetrical configuration in relation to each other, one chamber provided for the reference gas, the other for the sample gas; resilient and flexible suspension means for suspending and positioning the test body in the gap in the absence of a force acting on the test body due to the interaction of the test body with the magnetic field so that for zero force the test body is maintained in symmetrical disposition with reference to the plane or line of symmetry (equilibrium position, one chamber to one side, the other chamber to the other side of said plane or line) when the contents of the chambers have equal magnetic susceptibility, the body extending in said zones of magnetic inhomogeneity, at least when in equilibrium position and with similar volume as to portions of the body defining the two chambers, as well as gas filling the chambers, the resilient and flexible suspension means tending to restore the equilibrium position when the test body is deflected therefrom, a difference in magnetic susceptibility of the gases in the chambers establishing a force tending to deflect the body from the equilibrium position; and means for providing indicating representation of the force tending to deflect the body from said equilibrium position in dependence upon the difference in magnetic susceptibility as between the reference gas in said one chamber and the sample gas in the other chamber.