IMPROVEMENTS RELATING TO COLORIMETER APPARATUS FOR ANALYSING LIQUID SPECIMENS

1286335 Photo-electric analysis and control WELSH NATIONAL SCHOOL OF MEDICINE 19 April 1971 [22 Jan 1970] 3177/70 Heading B1X [Also in Division G1] An electro-optical test apparatus for testing liquid specimens and recording the results and which may comprise for example a colorimeter, photometer, spectrophotometer, polarometer or refractometer is provided with a controlled sample induction arrangement and an electrical switch mounted for operation by the foot and the actuation of which controls the induction and recording. The arrangement leaves the hands free to transfer a sampling tube from one sample to another so that tests may be performed in rapid succession and means is provided for zeroing the recorder between samples. The sampling may be by a continuously-running suction pump with a valve controlled by the switch or by an intermittently operated pump. A peristaltic pump may be used. In the flow cell Fig. 2 the sample admitted at 21 flows downpassage 24, up a vertical section 25, across a passage 26 and out through passages 22, 27, the sample being investigated in passage 26. A neon bulb is lit to indicate the period of investigation.