Patent GB-1176392-A (GB)
Title: Automatic Analysis Apparatus
IPC: G01N21/25
Filed: 1967-01-30
Abstract: 1,176,392. Optical apparatus; fluid regulation & distribution. TECHNICON CORP. Jan. 30, 1967 [Feb. 23, 1966], No. 4370/67. Headings G2J and G3H. [Also in Division G1] A multi-channel photo-electric colorimeter for investigating a plurality of samples, has an arcuate array of sample flow cells, each associated with a corresponding photo-detector, arranged around a centrally located light source. Optical arrangement, Fig. 3. Light from a lamp 48 cooled by a fan mounted beneath it, passes through a heat resistant transparent tube 34 to the lens system 98. This can be adjusted longitudinally with respect to the optical axis by sliding along on mounting member 91 to enable focusing of light on to the flow cell. Light then passes through an assembly 130 comprising a diaphragm adjustable by a screw (156, Fig. 4, not shown) and an aperture in a slide member 162, which can be moved up to cut off the beam. The beam passes through interference filters 182, 184 into the flow cell 168. This has an inlet 170, a debubbler outlet 172 and waste 176. Light passing through the flow cell reaches the detector - either a photo-cell 196 or vacuum tube device 198 - through an aperture baffle 201, providing light-tightness between the flow cell and detector chamber. The flow cell mounting and detector chamber are mounted on a cradle 166, which can be adjusted laterally (angularly about the axis of ball detent 230) or longitudinally with respect to the optical axis, and which is releasably mounted on the base 22 by means of the ball detent 230 and a bolt (234). Two of the flow cells of the arcuate array are modified for use as references, when the normal flow cell is replaced by a solid glass body or a sealed cell containing reference fluid. Analytical system, Fig. 11 (not shown). The colorimeter may form part of an analytical system which also includes a flame spectrometer, in which system an initial sample is drawn off as stream off a sequential samples which are divided into a plurality of quotient streams which are reacted with different reagents and passed through different flow cells of the colorimeter for evaluation. The initial samples of blood or urine &c. are disposed in respective containers (300) of a turn-table (301). An off-take tube is inserted into each container in turn and a peristaltic pump (304) draws off the samples as a stream of sequential liquid segments which are then separated to flow in parallel conduits as quotient streams of segments. The quotient streams may be passed for dialysis at (308) and gas separation at (310) and re-agents added, before passing through different flow cells of the colorimeter 8. In the system described only six flow cells are used, with two reference cells. A sample in one conduit (341a) may be analyzed for albumin by addition of an H. A. B. A. re-agent; that in another (314b) for total protein by a biuret re-agent; that in another (314c) for chlorides; that in another (314d) for carbon by addition of a CO 2  re-agent; that in another (314e) for glucose by an orcinol solution; that in another (314f) for urea nitrogen by diacetyl monoxime and ferric alum. The sample in a further conduit (314g) is analyzed in the spectro-photometer (312) e.g. for sodium and potassium using lithium sulphate as a standard. The recording system comprises a main chart recorder (320) receiving signals from the colorimeter spectro-photometer through a bridge network (322), and a monitoring chart recorder, printing, for example, three continuous records, or a monitoring meter. These are controlled by switch (324), which switches in sequence the outputs of the various flow cell detectors, reference cell detectors, and spectro-photometer detectors to the bridge (322), and a monitoring switch (328) controlling which output signals are recorded on the monitoring recorder (326). The system is designed so that only a single trace is recorded on the main recorder (320), this being a series of peak valves - one for each photo-cell of the colorimeter and for each spectro-photometer measuring photo-cell (376) - while at any one time the monitoring recorder prints continuous output curves from three sample channels those chosen being decided by the position of the switch (328). Step functions in the curves indicate switching from one channel to another, and indicator lamps which samples are being investigated at any one time. This facility for recording only peak valves requires that the samples are fed to the respective flow cells at different times so that the peak valves are not all obtained at the same time. To do this fluid flow restrictors (330) are provided which are adjustable so that the sequence of arrival of samples in the flow cells and spectro-photometer flame is variable as required. Variable fluid-flow restrictor. A suitable type comprises a flexible tube 338, Fig. 13, in the form of a flat spiral clamped between two plates 332 and 336 by means of a clamping bar 352 pivoted at 354 and movable towards plate 332 by means of a nut 364 advancable along threaded rod 358. A ball bearing ensures that the clamping action is at the centre of plate 336. The clamping squashes the tube 338 on an elliptical curved section, Fig. 16 (not shown).