GB656480A - Optical apparatus for the study of liquids - Google Patents

Abstract

656,480. Optical apparatus. STERN, K. G. March 31, 1948, No. 9063. Convention date, April 3, 1947. [Class 97 (i)] An optical apparatus for analysing a liquid by the moving boundary method comprises a chamber which can be refrigerated and maintained at substantially zero relative humidity and which contains a line source of visible or infra-red radiation, a vessel for supporting a column of the liquid to be analysed, an optical system for projecting the radiation through opposed transparent walls of the vessel and through said liquid, a rotatable diaphragm located in the path of the radiation emerging from said liquid column and having a radiation transmitting portion and a radiation intercepting portion, and a radiation detecting member positioned beyond said diaphragm in the path of said radiation. As shown, the apparatus comprises a refrigerator cabinet 11 in which is supported a tank 13 containing a constant temperature bath. In this bath is immersed a vessel 19 containing the liquid to be analysed, such vessel being for example an electrophoresis, diffusion or adsorption cell. Through a transparent portion 20 of vessel 19 is projected by means of a lens 25 and mirror 29 radiation emitted by a source 30 and passing through a slit 32. The radiation from the liquid passes through a window 23 in tank 13 and is directed downwards at 35 on to a diaphragm 39 which is rotatable through gearing actuated by an external knob 47. Diaphragm 39 has the form shown in Fig. 4, wherein the parts 64, 65, 66 and 67 are transparent to the radiation from source 30. After passing through the diaphragm the light passes through a lens 48 and is then turned through a 180 degrees by mirrors 49, 54 to travel upwardly through a cylindrical lens 55 on to a translucent or fluorescent screen or photographic plate 57 via a mirror 52. The lens 25 forms an image of the source 30 at the diaphragm 39 ; lens 48 is focused on the window 20 in vessel 19 and projects an image thereof on to the screen or plate 57; and the cylindrical lens 55 is focused on the diaphragm 39 and is arranged with its geometrical axis normal to the path of the radiation. Lens 25 may be replaced by two lens 25 and 25<SP>1</SP> arranged so that the radiation travelling therebetween is parallel and diaphragm 39 may be positioned at 391.