GB897179A - Apparatus for the measurement of gaseous fluids exhibiting magnetic properties - Google Patents

Abstract

897,179. Determining relative quantities of fluid mixture constituents. HUMMEL, H. July 15, 1958 [July 16, 1957], No. 22611/58. Class 37. Apparatus for determining the proportion of a fluid with paramagnetic susceptibility in a fluid mixture comprises a magnetic circuit structure including a yoke of ferromagnetic material with a gap, means for producing a magnetic field in said gap, means for introducing into the gap a sample of the fluid mixture to be analysed, control means externally of the gap and in fluid communication with said introducing means for cyclically varying the quantity of the fluid mixture in the gap and means for detecting and measuring the cyclical variations of the magnetic flux in the yoke. The flux between polepieces 2, 3, or across the gap of a pot magnet 31, 32, may be produced by a permanent magnet 1 or by a winding such as 34. A gas mixture (e.g. nitrogen and oxygen) to be analysed is introduced into a sample chamber 4, or 33, through constriction 5, or pipe 39, and is exhausted through constriction 6, or vents 43, 44 and 45, 46; and the gas in the chamber is subjected to the action of a cyclically reciprocating piston 8 or a periodically driven membrane or a rotating valve arrangement such as 38. The resultant flux modulation induces an alternating voltage in a coil 10 or 37, which may be amplified, rectified and applied to an electrical recorder which may be calibrated in terms of, say, oxygen content. When the valve arrangement is used, samples of the mixture and of a reference gas, e.g. nitrogen, which reference gas is supplied through pipe 41, may be introduced in alternation. Specification 588,496 is referred to.