GB712700A - Improvements in or relating to flame photometers - Google Patents

Abstract

712,700. Analysing solution photo-electrically. EVANS ELECTROSELENIUM, Ltd., and COLLINS, G. C. Sept. 10, 1952 [Sept. 10, 1951], No. 21283/51. Class 40 (3) A photometer for testing the quantity of a given element in a test solution comprises a burner supplied with a mixture of combustible gas, air and atomized test solution, light from the burner flame passing through a filter which allows only light produced by burning the e'ement in a colourless flame to reach a photoelectric cell, a galvanometer being provided responsive to the cell output. As shown, the solution under test is drawn through a capillary tube in a protective sleeve 10 by air which is supplied to the atomizer through a flexible tube (not shown). Thus a fine spray enters a mixing chamber 1 through nozzle 25. A further flexible tube 46 supplies a combustible gas such as coal gas, propane or butane which also enters the moving chamber near the point of entry of the spray. The moving chamber is provided with baffles 61, 62 which ensure that the gas, air and atomized test solutions are intimately mixed. The mixture passes to a burner 2 where it is burned, the light from the flame being reflected by concave mirror 12, condensed by a lens 13 passed through a filter 15 and a plain glass window 16 and received by a photo-electric cell 14. The end of the burner is flattened and has rows of holes 22 so that the flame is a flat one parallel to the surface of the photo-electric cell. The cell supplies a mirror galvanometer 17 receiving light from a source 48 and directing it into a fixed mirror 49 which reflects it to a translucent scale in the instrument casing. The zero of the galvanometer is adjustable by a knob 19 and a cam (not shown) which co-operates with a lever 59 to rotate the instrument movement as a whole. The range of the galvanometer may be adjusted by a potentiometer 20 calibrated in multiples of the galvanometer reading. The air supply to the instrument is through a nipple 31 and is controlled by a needle valve 35. The gas supply is through a nipple 39 and is controlled by a needle valve 4 and a pressure regulator 40. A recess 56 is provided in the side of the instrument housing which enables a beaker to be placed beneath the end of capillary tube 10. The housing is provided with a hood which pivots to allow access to the parts beneath. The burner is provided with a chimney 50 and the hood has a perforated plate above the chimney.