GB750723A - Refractometer for liquids and gases - Google Patents

Abstract

750,723. Refractometers. LKB-PRODUKTER FABRIKSAKTIEBOLAG. March 22, 1954 [April 18, 1953], No. 8323/54. Class 97 (1). An unknown and a reference substance are contained in compartments of a cell F having parallel outer walls and a dividing wall perpendicular to both. The cell is mounted on a turntable M and means is provided for measuring the deviation of a parallel light beam transmitted by the cell. In the form shown the slit D is illuminated by a source A with condenser B and filter C, the emergent light being collimated by a lens E before falling on the cell. The light transmitted by the cell falls on a fixed inclined reflector G and a reflector A by rotation of which the image formed by a lens I and observed by an eyepiece L may be aligned with a cross-hair K observed in an eyepiece L. A linkage for rotating the reflector H comprises a slidable bar X carrying a transverse block Z with a groove V engaged by a pin U at the end of an arm T coupled by 4: 1 reduction gearing S, R to the reflector. It is shown that this provides a linear relationship between the movement of the bar X and the difference between the refractive indices of the substances in the cell. The system I, K, L may be rotated instead of the reflector H. The gear ratio S: R is then required to be 1: 2. The sensitivity of the instrument is determined by rotation of the cell by the arm N moving over the scale P. The cell for a reference substance may be replaced by a glass block acting as the reference standard.