Patent GB-941777-A (GB)
Title: A chemical analysis system
IPC: G01N21/78
Filed: 1960-08-25
Abstract: 941,777. Chemical analysis apparatus. K. LANDENDORF, E. LANDENDORF, W. LANDENDORF, P. LANDENDORF, E. LANDENDORF, and K. F. LANDENDORF. Aug. 25, 1960, No. 29377/60. Heading B1X. A chemical analysis system comprises a test liquid supply, a liquid reagent supply, a mixture vessel, a fixed volume measuring system capable of connection with the test liquid supply and the mixture vessel, movable element through which extends a bore of known volume capable of connection with the reagent supply in a first position and the mixture vessel in a second position and synchronizing means such that, when reagent is being supplied to the bore in the first position, liquid sample is being fed to the fixed volume measuring system, and, when the reagent is being emptied into the mixture vessel, the liquid sample from the fixed volume measuring system is likewise being fed to the mixture vessel. In a preferred arrangement of the apparatus reagent entrapped in the bore in the first position is flushed out, in the second position, by the measured volume of sample, into the mixture vessel. A schematic diagram of the system is illustrated in Fig. 1. A sample liquid is fed to a supply line 10 through a regulating needle valve 11 into a blank cell 12. From cell 12 the sample is fed through supply line 14 to a stopcock 15 having a bore 19 and then into a system of tubing 16 and an overflow chamber 17. Tubing 16 and overflow chamber 17 constitute a fixed volume measuring system. Stopcock 15 is driven by a motor 18. When bore 19 is in the position shown the liquid sample will flow under pump or gravity pressure to the fixed volume measuring system. A reagent supply is fed through a supply line 29 to a plug stopcock 30 having a precision bore 31. In the preferred version only one stopcock is used so that stopcock 30 may be taken to indicate a portion of stopcock 15 having a second bore 31. In line with bore 31 when it is in line with supply line 29 is another line constituting a portion of sight glass 32. Thus as the system is open at both ends when bore 31 connects lines 29 and 32 the air contained in the bore will rise and be discharged through the sight glass. Plug stopcock 30 is preferably driven by motor 18 in synchronism with plug stopcock 15, such that, when bore 19 is positioned to fill the overflow system 16, 17 sample bore 31 is positioned to be filled with reagent and only after bore 19 is turned out of alignment with the supply line 14 is bore 31 aligned with overflow system 16 and effluent line 34. When bore 31 has been filled with a fixed volume of reagent plug stopcock 30 is realigned with the overflow system 16, 17 so that the fixed volume of sample flows through bore 31 washing out the reagent into mixing chamber 36. The mixture passes from the mixing chamber to cell 43 through supply line 42 and is analyzed in comparison with blank cell 12 by means of the photoelectric cells 52 and 53. In the preferred arrangement of the invention a single plug stopcock containing bores 19 and 31 is used. A single stopcock containing a plurality of bores such as 31 may be used so that more reagents may be employed. Alternatively more than one stopcock may be used provided that the drive system links the plurality of stopcocks together. The stopcock may be replaced by a slide with a bore extending through it to parallel flat walls engaged by other flat walls producing the same action by a linear sliding movement.