GB1192008A - Improvements in or relating to Colorimeters - Google Patents

Abstract

1,192,008. Photo-electric colorimeters. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. Sept. 11, 1967 [Sept. 14, 1966], No.40980/66. Heading G1A. A colorimeter comprises a plurality of flow cells spaced around a circle with their axes transverse to the circumference a light source directing a beam of light axially through each cell means for guiding light from said plurality of flow cells to a common light intensity measuring means and a shutter arranged to rotate in a circular path between said light source and the light guiding means, said shutter having an aperture for admitting light through to said measuring means for each cell in turn as the shutter rotates. Fifteen pairs of flow cells 23, 24, Fig. 2 for sample and reference fluids are illuninated by tungsten or quartz iodine lamps 25 through different filters 26. The light passing through the cells 23, 24 is conducted by fibre optic bundles 36, 37 respectively to two recording photometers. A shutter 28 is rotated by a motor between the lamps 25 and the filters, the shutter having an aperture of size equal to the circumferential distance between corresponding cells of adjacent pairs whereby light from each of these cells falls in turn on the associated photometer with no blank interval. Test procedure. A sample whose response to a reagent is to be measured at 14 different wavelengths is split into 28 units, 14 of which are treated with reagent and put in the flow cells of 14 pairs. The remaining pair of cells (with which the aperture in shutter 28 is initially aligned) contains water for standardization. The shutter 28 is then rotated once and each time the aperture coincides with a pair of flow cells, a micro-switch, 47, 48 &c. actuates the recording of the sample and reference absorption at the wavelength of the associated filter. Flow cells. Each flow cell has an inlet pipe having a pair of electrodes and an outlet pipe connected through a valve to a suction source. When the inlet pipe is dipped in a test tube of sample a circuit through the electrodes opens the valve and sample flows through the cell purging the previous sample until the level in the test tube falls below the level of the electrodes. The inlet and outlet tubes are positioned so that the end faces of the flow cell are washed by the flowing sample. In a modification, Fig. 1, (not shown) the lamps are located radially inward of the flow cells and the fibre optic bundles start from points radially outwards from the flow cells. The shutter may be between lamp and filter, filter and flow cell or flow cell and fibre optic bundle. All the sample and reference cells may be concentrated in separate sectors of the circle and the shutter provided with two apertures.