Liquid Analysis Apparatus

Abstract

A rotary analytical device for use with a reagent cartridge. The cartridge may have a housing, an axis, analysis chambers spaced from and located circumferentially about the axis, and a magnetically movable element located in and movable within each analysis chamber to mix fluid in the analysis chamber. The rotary analytical device may have a housing with a cavity having an axis, an impeller extending into the cavity and rotatable about the axis to receive and rotate the cartridge, a motor to rotate the impeller, at least one magnetic element near the cavity and offset from the axis, a light source in the housing to direct a beam of light into the cavity and through the analysis chamber of the cartridge, and a light sensor to receive light from the analysis chamber.

1 . A rotary analytical device comprising:
 a housing having a cavity formed therein, the cavity being defined by a bottom wall and at least one side wall, the cavity having an axis;   an impeller extending into the cavity and rotatable about the axis;   a motor mounted within the housing and connected to the impeller, the motor adapted to rotate the impeller;   at least one magnetic element in the housing at a location proximate to the cavity and offset from the axis;   at least one light source in the housing and arranged to direct a beam of light into the cavity; and   at least one light sensor in the housing and arranged to receive light from the at least one light source, the sensor being sensitive to light of a color emitted by the light source.   
     
     
         2 . A rotary analytical device according to  claim 1 , wherein there are a plurality of magnetic elements mounted to the housing. 
     
     
         3 . A rotary analytical device according to  claim 2 , wherein magnetic elements are offset at equal distances from the axis, and spaced apart circumferentially from one another. 
     
     
         4 . A rotary analytical device according to  claim 3 , wherein the housing includes a lid and a body portion, the lid being hinged to the body portion, the cavity being locate in the body portion and enclosed by the lid, and wherein some of the plurality of magnetic elements are mounted in or below the bottom wall and the remainder of the magnetic elements are mounted in the lid, the magnets in the lid not being aligned vertically with the magnetic elements on the bottom wall such that they are circumferentially spaced apart from each other. 
     
     
         5 . A rotary analytical device according to  claim 4 , in combination with a cartridge mountable on the impeller with the cavity for being rotated by the impeller, the cartridge comprising:
 a cartridge housing having a central axis coincident with the axis of the impeller;   a plurality of analysis chambers in the housing, the chambers being spaced apart from the axis and located circumferentially about the axis; and   a magnetically movable element located in each analysis chamber and movable within the analysis chamber, the element adapted to cause the mixing of fluid in the analysis chamber.   
     
     
         6 . A rotary analytical device according to  claim 5 , wherein the magnetic elements are positioned in the housing so as to be substantially near the magnetically movable elements of the cartridge such that when the cartridge is rotated within the cavity, as the magnetically movable element passes a magnetic element, the magnetically movable element is attracted to or repelled from the magnetic element. 
     
     
         7 . A rotary analytical device according to  claim 1 , wherein there are a plurality of said light sources spaced apart circumferentially from one another and at substantially the same radial distance from the axis of the cavity; and wherein there are a plurality of light sensors, each light sensor being sensitive to light received from one of the light sources. 
     
     
         8 . A rotary analytical device according to  claim 7 , wherein there are an equal number of light sources and light sensors, and wherein the device is configured such that a light sensor analyzes light only from a specific light source. 
     
     
         9 . A rotary analytical device according to  claim 8 , further comprising circuitry operative to measure time-varying light intensities sensed by the plurality of sensors, associate the intensities with ones of a plurality of locations on a cartridge rotating on said impeller, and generate an output responsive to the intensities at specific ones of the locations. 
     
     
         10 . A rotary analytical device according to  claim 9 , wherein the output is responsive to intensities at specific wavelengths and/or to specific variations in intensity with wavelength at the locations. 
     
     
         11 . The analytical cartridge of  claim 5 , wherein the analysis chamber comprises a first chamber section containing the magnetically movable element and a second chamber section fluidly connected with the first chamber section, and wherein the fluid connection between the first and second chamber sections includes an axial slot that is narrower than a minimum dimension of the magnetically movable element. 
     
     
         12 . The analytical cartridge of  claim 11 , wherein the analysis chamber contains a photometric reagent, and wherein the housing above and below the second chamber section includes a portion that is transparent to light of at least one wavelength appropriate for photometry of the reagent. 
     
     
         13 . The analytical cartridge of  claim 12 , further comprising at least one reference chamber without a magnetically movable element. 
     
     
         14 . The analytical cartridge of  claim 12 , comprising a distribution gallery located radially inward from and fluidly connected to the analysis chambers, the distribution gallery adapted to distribute a liquid to be analyzed to the analysis chambers through centrifugal force upon rotation of the cartridge about the axis. 
     
     
         15 . The analytical cartridge of  claim 14 , wherein the distribution gallery has an inlet for receiving the liquid to be analyzed at one end, and is connected to an overflow chamber at the other end; and wherein the fluid connection with the analysis chambers includes a plurality of channels located between the inlet and the overflow chamber and extending radially from the distribution gallery, each channel connected to an analysis chamber. 
     
     
         16 . The analytical cartridge of  claim 13  wherein the analysis chambers and the at least one reference chamber are evenly spaced circumferentially about the axis, wherein the at least one reference chamber does not have a first chamber section, and wherein the overflow chamber is larger than one of the analysis chambers, and the overflow chamber and the at least one reference chamber together occupy the same space as two said analysis chambers. 
     
     
         17 . The analytical cartridge of  claim 12 , wherein the magnetically movable element is a ball bearing.