Patent Publication Number: US-2021170414-A1

Title: Methods and apparatus to mitigate bubble formation in a liquid

Description:
RELATED APPLICATIONS 
     This patent arises from a continuation of U.S. application Ser. No. 16/107,826 (now U.S. Pat. No. 10,926,263), titled “METHODS AND APPARATUS TO MITIGATE BUBBLE FORMATION IN A LIQUID,” filed Aug. 21, 2018, which is a continuation of U.S. application Ser. No. 13/801,451 (now U.S. Pat. No. 10,058,866), titled “METHODS AND APPARATUS TO MITIGATE BUBBLE FORMATION IN A LIQUID,” filed Mar. 13, 2013, both of which are hereby incorporated by this reference in their entireties. 
    
    
     FIELD OF THE DISCLOSURE 
     This disclosure relates generally to fluid analyzers and, more particularly, to methods and apparatus mitigate bubble formation in a liquid. 
     BACKGROUND 
     Automated analyzers are used to analyze samples including biological material gathered from patients for diagnostic purposes. Generally, analysis of a sample involves reacting the sample with one or more reagents in a liquid container. Some automated analyzers store reagents in containers on a carousel. When a particular reagent is needed, the carousel is rotated to move the container holding the reagent to be adjacent an aspirating/dispensing device. The carousel moves by accelerating and decelerating, which subjects the reagents to rotational forces that could cause bubbles to form in the liquid. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an example cartridge that is holding a plurality of example containers and which is coupled to a portion of an example carousel. 
         FIG. 2  is a cross-sectional view of a first container of the example cartridge of  FIG. 1  taken along the A-A line of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of a second container of the example cartridge of  FIG. 1  taken along the A-A line of  FIG. 1 . 
         FIG. 4  is a side, cross-sectional view of the example cartridge of  FIG. 1  taken along the B-B line of  FIG. 1  when the example cartridge is substantially stationary. 
         FIG. 5  is a side, cross-sectional view of the example cartridge of  FIG. 1  taken along the B-B line of  FIG. 1  when the example cartridge is rotating. 
         FIG. 6  is a graph showing a velocity of the example cartridge on the carousel of  FIG. 1  over a period of time. 
         FIG. 7  is a top, cross-sectional view of an alternative example container disclosed herein. 
         FIG. 8  is a perspective, cross-sectional view of the example container of  FIG. 7  taken along the C-C line of  FIG. 7 . 
         FIG. 9  is a flowchart representative of an example method disclosed herein. 
     
    
    
     Some of the figures or some of the portions of the figures may not be to scale. Instead, to clarify multiple layers and regions, the thickness of the layers may be enlarged in the drawings. Wherever possible, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. As used in this patent, stating that any part (e.g., a layer, film, area, or plate) is in any way positioned on (e.g., positioned on, located on, disposed on, or formed on, etc.) another part, means that the referenced part is either in contact with the other part, or that the referenced part is above the other part with one or more intermediate part(s) located therebetween. Stating that any part is in contact with another part means that there is no intermediate part between the two parts. 
     DETAILED DESCRIPTION 
     Disclosed herein are methods and apparatus to mitigate bubble formation in a liquid such as, for example, a liquid reagent in a container of an automatic diagnostic analyzer, which may be, for example, a clinical chemistry analyzer, an immunoassay analyzer, and/or a hematology analyzer. Some reagents used in automatic diagnostic analyzers include a liquid and one or more surfactants (e.g., detergents). Automatic diagnostic analyzers typically rotate reagent containers or bottles about an axis and/or in an oscillating manner, and the rotation, acceleration and/or deceleration imparts forces on the contents of the containers, which may agitate the contents of the containers. 
     When surfactants and/or reagents are agitated, bubbles and foam may form. Example containers disclosed herein use baffles to mitigate (e.g., reduce and/or substantially minimize) bubble formation in the liquid and enable the liquid to quickly settle after the containers decelerate to a substantially stationary state. Some example baffles disclosed herein extend from bottom walls of the containers and are spaced apart from sidewalls, end walls, and top walls of the containers. In some examples, the baffles are c-shaped and have concave portions facing an axis of rotation of the containers. 
     In the examples disclosed herein, the top walls define throats and crowns. When the example containers rotate, the liquid flows around the baffles and into the crowns without flowing into the throats and out of the containers. In some examples disclosed herein, the containers have rounded-rectangular shapes that provide greater space utilization in diagnostic systems than many known container configurations. As a result, using examples described herein, analyzers can have an increased load capacity and/or smaller size, compared to many known systems. The example containers can be created with fabrication techniques such as, for example, injection molding and/or laser welding, which reduce costs compared to the fabrication techniques used to create many known container configurations. 
     Disclosed herein is an example apparatus that includes a reagent container having a first sidewall and a second sidewall opposite the first sidewall. The example container further includes a top wall coupled to the first sidewall and the second sidewall. The example container also includes a bottom wall opposite the top wall, and the bottom wall is coupled to the first sidewall and the second sidewall. The example container also includes a first baffle extending from the bottom wall. The example first baffle is spaced apart from the first sidewall, the second sidewall, and the top wall. 
     In some examples, the apparatus also includes a second baffle extending from the bottom wall. The second baffle may be spaced apart from the first sidewall, the second sidewall, the top wall and the first baffle. In some examples, the first baffle has a first height and the second baffle has a second height greater than the first height. The first baffle and the second baffle may be positioned radially relative to an axis of rotation of the apparatus. In some examples, the first baffle has a c-shaped cross-section. 
     In some examples, the top wall includes a first portion and a second portion. The first portion may be at a first height relative to the bottom wall and the second portion may be at a second height relative to the bottom wall greater than the first height. In some examples, the first portion of the top wall defines an aperture. In some examples, the second portion of the top wall defines a crown, and liquid is to flow around the first baffle and into the crown when the apparatus is rotated. 
     In some examples, the apparatus also includes a carrier, and the container is removably coupled to the carrier. In some examples, the bottom wall is curved. In some examples, the apparatus also includes a first curved end wall and a second curved end wall opposite the first curved end wall. The first end wall and the second end wall may couple the first sidewall and the second sidewall. 
     Another example apparatus disclosed herein includes a bottom wall, a first baffle cantilevered from the bottom wall, and a second baffle cantilevered from the bottom wall. The example first baffle is spaced apart from the example second baffle, and the first baffle and the second baffle are positioned radially relative to an axis of rotation of the apparatus. 
     In some examples, the first baffle is curved. In some examples, the first baffle has a c-shaped cross-section and is oriented such that a concave portion of the c-shaped cross-section faces the axis of rotation of the apparatus. In some examples, the second baffle has a c-shaped cross-section and is oriented such that a concave portion of the c-shaped cross-section of the second baffle faces the axis of rotation of the apparatus. 
     Another example apparatus disclosed herein includes a bottom wall, a first sidewall coupled to the bottom wall, and a top wall coupled to the sidewall. The example top wall has a first portion and a second portion. The example first portion is at a first height relative to the bottom wall, and the example second portion is at a second height greater than the first height relative to the bottom wall. The example apparatus also includes a first baffle having a third height different than the first height and the second height. In some examples, the baffle extends from the bottom wall. In some examples, the third height is greater than the first height. 
     In some examples, the bottom wall, the first sidewall and the top wall define a chamber, and the first portion of the top wall comprises an aperture in fluid communication with the chamber. 
     In some examples, the first baffle is spaced apart from the first sidewall. In some examples, the apparatus also includes a second sidewall, and the first baffle is spaced apart from the second sidewall. The example apparatus may also include a first end wall and a second end wall opposite the first end wall. The first end wall and the second end wall may be coupled to the first sidewall and the second sidewall. In some examples, the first baffle is spaced apart from the first end wall and the second end wall. In some examples, a first distance between the first sidewall and the second sidewall adjacent the first end wall is less than a second distance between the first sidewall and the second sidewall adjacent the second end wall. 
     In some examples, the apparatus also includes a second baffle, and the first baffle and the second baffle are disposed radially relative to an axis of rotation of the apparatus. In some examples, the second baffle extends from the bottom wall. In some examples, the second baffle has a fourth height different than the first height, the second height and the third height. In some examples, the fourth height is less than the first height, and the third height is greater than the first height. 
     In some examples, the apparatus also includes a liquid reagent that may be disposed below the first height when the apparatus is stationary. In some examples, a portion of the liquid reagent is disposed between the first height and the second height during rotation of the example apparatus. 
     Also disclosed herein is an example method that includes rotating a container about an axis of rotation. In some examples, the container includes a bottom wall, a sidewall coupled to the bottom wall, and a top wall coupled to the sidewall opposite the bottom wall. An example top wall includes a first portion and a second portion. The first portion may be at a first height relative to the bottom wall, and the second portion may be at a second height greater than the first height relative to the bottom wall. The example second portion defines a crown. The example container also includes a first baffle coupled to the bottom wall and spaced apart from the sidewall and the top wall. The example container further includes a liquid. The example method also includes displacing the liquid around the first baffle during rotation, and displacing the liquid into a space defined by the crown during rotation. 
     In some examples, bubble formation in the liquid is decreased by the displacing of the liquid around the first baffle and the displacing of the liquid into the space defined by the crown. In some examples, the method also includes ceasing rotation and aspirating a portion of the liquid. 
     In some examples, the example method includes rotating the container with a substantially constantly changing velocity. Also, in some examples, the example method includes increasing a velocity of the container non-linearly over time and decreasing the velocity of the container nonlinearly over time. 
     Another example apparatus includes a container defining a chamber to hold a reagent. The example container includes a first sidewall, a second sidewall and a top wall. The example apparatus also includes a first baffle having a c-shaped cross-section disposed in the chamber. A first portion of the example first baffle is spaced apart from the top wall and at least one of the first sidewall or the second sidewall to enable a liquid in the chamber to flow around the first baffle to mitigate bubble formation in the liquid.  
     In some examples, a concave portion of the first baffle is to face an axis of rotation of the container. In some examples, the top wall defines a crown, and the first baffle extends into a space defined by the crown. In some examples, the apparatus also includes a second baffle having a c-shape cross-section, and the second baffle is disposed in the chamber. A second portion of the example second baffle may be spaced apart from the first baffle, the top wall and at least one of the first sidewall or the second sidewall. 
     In some examples, the first baffle and the second baffle are different heights. In some examples, the first baffle and the second baffle are positioned radially relative to an axis of rotation of the apparatus. The example apparatus may also include a first end wall and a second end wall coupled to the first sidewall and the second sidewall. The first portion of the first baffle may be spaced apart from the first end wall and the second end wall. 
     Turning now to the figures,  FIG. 1  is a perspective view of an example cartridge  100  coupled to a carousel  102  of a diagnostic analyzer. In the illustrated example, the carousel  102  includes a platform  104  on which the cartridge  100  is supported. The cartridge  100  may be transported to and/or placed on the platform  104  manually, by a robotic device, via a conveyer, and/or via any other device and/or technique. During operation of the example carousel  102 , the platform  104  and, thus, the cartridge  100  rotates about a first axis of rotation  106  along a substantially circular path  108  defined by the carousel  102 . In some examples, multiple cartridges are coupled to the platform  104 . 
     In some examples, the platform  104  periodically and/or aperiodically accelerates and decelerates while moving along a path  108  defined by the carousel  102 . In the illustrated example, the path  108  is substantially circular. In other examples, the path  108  is other shapes. In some examples, the platform  104  moves periodically or aperiodically in one direction. In other examples, the platform  104  moves in a back-and-forth (e.g., oscillating) motion. For example, the platform  104  may repeatedly move a first distance in a first direction (e.g., clockwise) and then a second distance in a second direction (e.g., counterclockwise) opposite the first direction. In some examples, the distance moved in the first direction is greater than the distance moved in the second direction such that the cartridge  100  on the platform  104  oscillates via the back-and-forth motion while it revolves about the first axis of rotation  106 . In some examples, after the platform  104  moves in the first direction, the platform  104  is substantially stationary for a given amount of time before moving in the second direction. In some examples, the first distance is approximately the same as the second distance such that the cartridge  100  moves to and from a given position on the path  108 . Other examples move in other manners. 
     In the illustrated example, the cartridge  100  includes a base or carrier  110 , a first container  112  and a second container  114 . The example carrier  110  is coupled to the platform  104  to rotate with the platform  104 . The example carrier  110  includes a seat  116 , a first end wall  118 , a second end wall  120  and a cover  122 . In the illustrated example, first ends  124 ,  126  of the first container  112  and the second container  114 , respectively, are coupled to the seat  116 , and second ends  127 ,  128  of the first container  112  and the second container, respectively, are coupled to the cover  122 . 
     In the illustrated example, the first container  112  and the second container  114  are arranged in the carrier  110  radially relative to the path  108  defined by carousel  102 . In the illustrated example, the first container  112  is disposed adjacent the first end wall  118  and the second container  114  is disposed adjacent the second end wall  120 . In some examples, the first container  112  and/or the second container  114  are rotatably coupled to the seat  116 . 
     Each of the containers  112 ,  114  is to hold a liquid  400 ,  402  ( FIG. 4 ). In some examples, the liquids  400 ,  402  include a sample to be analyzed, one or more reagents, microparticles and/or surfactants (e.g., detergents). The example cover  122  includes a first aperture  130  and a second aperture  132  to provide access to the first container  112  and the second container  114 , respectively. In the illustrated example, a first cap  134  is coupled to the first container  112 , and a second cap  136  is coupled to the second container  114 . The first cap  134  and the second cap  136  prevent the contents of the containers  112 ,  114  from flowing out of the containers  112 ,  114  when the cartridge  100  is being lifted, handled, maneuvered, transported, etc. In some examples, the caps  134 ,  136  are decoupled from the containers  112 ,  114  when the example cartridge  100  is disposed on the carousel  102 . In some examples, the caps  134 ,  136  are decoupled from the containers  112 ,  114  prior to the example cartridge  100  being disposed on the carousel  102 . In the illustrated example, the carrier  110  includes a first handle  138  and a second handle  140  to facilitate grasping, holding, lifting, maneuvering and/or transporting of the cartridge  100  by a human (e.g., manually) and/or a robot. 
     In the illustrated example, the first cap  134  extends out of the first aperture  130 , and the second cap  136  extends out of the second aperture  132  to enable the first cap  134  and/or the second cap  136  to be removed from the first container  112  and the second container  114 , respectively. When the first cap  134  and the second cap  136  are removed, the liquid may be deposited into and/or removed from the first container  112  and the second container  114 . In some examples, a pipettor and/or other device(s) is inserted into the first container  112  and/or the second container  114  via the apertures  130 ,  132  to determine a liquid level inside, dispense a liquid into and/or aspirate a liquid from the first container  112  and/or the second container  114 . As described in greater detail below, the example first container  112  and the example second container  114  mitigate (e.g., reduce and/or substantially minimize) bubble formation in the liquids  400 ,  402 , thereby enabling accurate liquid level measurements to be taken via the pipettor and/or other device(s). 
       FIG. 2  is a cross-sectional view of the example first container  112  of  FIG. 1  along line A-A of  FIG. 1 . In the illustrated example, the first container  112  includes a first sidewall  200 , a second sidewall  202 , a first end wall  204 , a second end wall  206 , a first bottom wall  208  and a first top wall  408  ( FIG. 4 ) defining a first fluid chamber  210 . The example first container  112  has a rounded-rectangular cross-sectional shape. In the illustrated example, the first sidewall  200  and the second sidewall  202  are substantially planar and parallel. The example first end wall  204  is opposite the example second end wall  206 . In the illustrated example, the first end wall  204  and the example second end wall  206  couple the first sidewall  200  and the second sidewall  202  and are curved away from a central, longitudinal axis of the first container  112 . In the illustrated example, a distance between the first sidewall  200  and the second sidewall  202  is less than a distance between the first end wall  204  and the second end wall  206 . Other examples have other cross-sectional shapes (e.g., circular, elliptical, rectangular, square, polygonal, wedged, etc.). 
     In the illustrated example, the first container  112  includes a first baffle  212 , a second baffle  214 , a third baffle  216  and a fourth baffle  218  disposed inside the first fluid chamber  210 . Other examples include other numbers of baffles (e.g., 1, 2, 3, 5, 6, etc.) In the illustrated example, the first baffle  212 , the second baffle  214 , the third baffle  216  and the fourth baffle  218  extend from the first bottom wall  208  toward the first top wall  408  ( FIG. 4 ). In some examples, the baffles  212 ,  214 ,  216 ,  218  extend from the first bottom wall  208  substantially parallel to or otherwise aligned with each other. In some examples, the baffles  212 ,  214 ,  216 ,  218  extend from the first bottom wall  208  toward the first top wall  408  ( FIG. 4 ) substantially parallel to or otherwise aligned with the axis of rotation  106  of the cartridge  100 . In the illustrated example, the baffles  212 ,  214 ,  216 ,  218  are positioned along an axis  220  radially relative to the axis of rotation  106  of the example cartridge  100 . The example baffles  212 ,  214 ,  216 ,  218  are spaced apart from each other along the axis  220 . In some examples, the baffles  212 ,  214 ,  216 ,  218  are spaced apart from each other by substantially equal distances. In the illustrated example, the baffles  212 ,  214 ,  216 ,  218  are spaced apart by approximately 14 to 18 millimeters. In other examples, the baffles  212 ,  214 ,  216 ,  218  are equally spaced apart from each other by other distances. In some examples, the baffles  212 ,  214 ,  216 ,  218  are spaced apart from respective adjacent baffles by different distances. For example, the first baffle  212  and the second baffle  214  may be spaced apart a first distance, and the second baffle  214  and the third baffle  216  may be spaced apart a second distance, different than the first distance. 
     The example baffles  212 ,  214 ,  216 ,  218  are also spaced apart from the first sidewall  200 , the second sidewall  202 , the first end wall  204  and the second end wall  206 . In the illustrated example, the baffles  212 ,  214 ,  216 ,  218  are spaced apart from the first side wall  200  by approximately one to two millimeters. The example baffles  212 ,  214 ,  216 ,  218  are also spaced apart from the second sidewall  202  by approximately one to two millimeters. Thus, in the illustrated example, the baffles  212 ,  214 ,  216 ,  218  are positioned approximately equidistant from the first sidewall  200  and the second sidewall  202 . In other examples, the baffles  212 ,  214 ,  216 ,  218  are spaced apart from the first sidewall  200  and/or the second sidewall  202  by other distances. Also, in some examples, one or more of the baffles  212 ,  214 ,  216 ,  218  are spaced from one or both of the first and second sidewalls  200 ,  202  by distances different than other ones of the baffles  212 ,  214 ,  216 ,  218 . 
     In the illustrated example, the baffles  212 ,  214 ,  216 ,  218  define respective channels  222 ,  224 ,  226 ,  228  facing the second end wall  206 . Thus, when the example cartridge  100  is disposed on the carousel  102 , the channels  222 ,  224 ,  226 ,  228  face the axis of rotation  106  of the cartridge  100 . In the illustrated example, the baffles  212 ,  214 ,  216 ,  218  are curved such that the baffles  212 ,  214 ,  216 ,  218  have c-shaped (e.g., semi-circular) cross-sectional shapes and concave portions  230 ,  232 ,  234 ,  236  of the example baffles  212 ,  214 ,  216 ,  218  define the channels  222 ,  224 ,  226 ,  228 . In the illustrated example, the baffles  212 ,  214 ,  216 ,  218  have substantially the same cross-sectional shape and size (e.g., radius of curvature and cross-sectional arc length). In other examples, the baffles  212 ,  214 ,  216 ,  218  have other cross-sectional shapes (e.g., crescent-shaped, a curved U-shape, an angled U-shape, etc.) and/or sizes. Also, in some examples, the baffles  212 ,  214 ,  216 ,  218  have shapes different from one or more of the other baffles  212 ,  214 ,  216   218 . As described in greater detail below, the example baffles  212 ,  214 ,  216 ,  218  mitigate (e.g., reduce and/or minimize) bubble formation in the liquid  400 ,  402  inside the example first container  112 . 
       FIG. 3  is a cross-sectional view of the example second container  114  of  FIG. 1  along line A-A of  FIG. 1 . In the illustrated example, the second container  114  includes a third sidewall  300 , a fourth sidewall  302 , a third end wall  304 , a fourth end wall  306 , a second bottom wall  308  and a second top wall  418  ( FIG. 4 ) defining a second fluid chamber  310 . The example second container  114  has a rounded-polygonal cross-sectional shape (e.g., a wedge shape). In the illustrated example, the third sidewall  300  and the fourth sidewall  302  are substantially planar and nonparallel. In the illustrated example, a first distance D 1  between the third sidewall  300  and the fourth sidewall  302  adjacent the fourth end wall  306  is less than a second distance D 2  between the third sidewall  300  and the fourth sidewall  302  adjacent the third end wall  304 . The example third end wall  304  is opposite the example fourth end wall  306 . In the illustrated example, the third end wall  304  and the fourth end wall  306  couple the third sidewall  300  and the fourth sidewall  302 . In the illustrated example, the third end wall  304  and the example fourth end wall  306  are curved away from a central, longitudinal axis of the second container  114 . In the illustrated example, the third end wall  304  has a greater cross-sectional arc length than the fourth end wall  306 . Other examples have other cross-sectional shapes (e.g., circular, elliptical, rectangular, rounded rectangular, square, etc.) and/or sizes. 
     In the illustrated example, the second container  114  includes a fifth baffle  312  and a sixth baffle  314  disposed inside the second fluid chamber  310 . Other examples include other numbers of baffles (e.g., 1, 3, 4, 5, 6, etc.) In the illustrated example, the fifth baffle  312  and the sixth baffle  314  extend from the second bottom wall  308  toward the second top wall  418  ( FIG. 4 ). In some examples, the baffles  312 ,  314  extend from the second bottom wall  308  substantially parallel to each other. In some examples, the baffles  312 ,  314  extend from the second bottom wall  308  toward the second top wall  418  ( FIG. 4 ) substantially parallel to the axis of rotation  106  of the cartridge  100 . In the illustrated example, the baffles  312 ,  314  are positioned along the axis  220  radially relative to the axis of rotation  106 . The example fifth baffle  312  is spaced apart from the example sixth baffle  314  along the axis  220 . In the illustrated example, the baffles  312 ,  314  are spaced apart by approximately 14 to 18 millimeters. In other examples, the baffles  312 ,  314  are spaced apart from each other by other distances. 
     The example baffles  312 ,  314  of  FIG. 3  are also spaced apart from the third sidewall  300 , the fourth sidewall  302 , the third end wall  304  and the fourth end wall  306 . In the illustrated example, the baffles  312 ,  314  are spaced apart from the third side wall  300  by approximately one to two millimeters. The example baffles  312 ,  314  are also spaced apart from the fourth sidewall  302  by approximately one to two millimeters. Thus, in the illustrated example, the baffles  312 ,  314  are positioned approximately equidistant from the third sidewall  300  and the fourth sidewall  302 . In other examples, the baffles  312 ,  314  are spaced apart from the third sidewall  300  and/or the fourth sidewall  302  by other distances. Also, in some examples, the fifth baffle  312  is spaced from the third sidewall  300  and/or fourth sidewall  302  a first distance, and the sixth baffle  314  is spaced from the third sidewall  300  and/or fourth sidewall  302  a second distance, different than the first distance. 
     In the illustrated example, the baffles  312 ,  314  each define a channel  316 ,  318  facing the fourth end wall  306 . Thus, when the example cartridge  100  is disposed on the carousel  102 , the channels  316 ,  318  face the axis of rotation  106  of the cartridge  100 . In the illustrated example, the baffles  312 ,  314  are curved such that the baffles  312 ,  314  have c-shaped (e.g., semi-circular) cross-sectional shapes and concave portions  320 ,  322  of the example baffles  312 ,  314  define the channels  316 ,  318 . In the illustrated example, the fifth baffle  312  has a greater cross-sectional size (e.g., arc length and radius of curvature) than the sixth baffle  314 . In other examples, the baffles  312 ,  314  have other cross-sectional shapes (e.g., crescent-shaped, a curved U-shape, an angled U-shape, etc.) and/or sizes. Also, in some examples, the cross-sectional shapes of the baffles  312 ,  314  do not match. As described in greater detail below, the example baffles  312 ,  314  mitigate (e.g., reduce and/or minimize) bubble formation in the liquid  402  inside the example second container  114 . 
       FIG. 4  is a cross-sectional view of the example cartridge  100  along line B-B of  FIG. 1 . In the illustrated example, the first container  112  contains the first liquid  400 , and the second container  114  contains the second liquid  402 . In the illustrated example, the first container  112  has a different liquid volume capacity than the second container  114 . In the illustrated example, ninety percent of the volume of the first fluid chamber  210  of the example first container  112  is filled with the first liquid  400  and, thus, the first container  112  contains approximately 75 milliliters of the first liquid  400 . Ninety percent of the volume of the example second fluid chamber  310  of the second container  114  is filled with the second liquid  402  and, thus, the second container  114  contains approximately 47 milliliters of the second liquid  402 . In the illustrated example, the cartridge  100  is substantially stationary and, thus, the first liquid  400  and the second liquid  402  are substantially level (e.g., a first surface  404  and a second surface  406  of the first liquid  400  and the second liquid  402 , respectively, are substantially horizontal). 
     In the illustrated example, the first top wall  408  of the first container  112  is coupled to the first sidewall  200 , the second sidewall  202 , the first end wall  204  and the second end wall  206  and has a first portion  410  adjacent the first end wall  204  and a second portion  412  adjacent the second end wall  206 . In the illustrated example, the top wall  408  is stepped such that the first portion  410  of the first top wall  408  is a first height or distance from the first bottom wall  208 , and the second portion  412  of the first top wall  408  is a second height or distance, which is less than the first height or distance from the first bottom wall  208 . Thus, the first portion  410  of the example top wall  408  defines a first crown  414 . In some examples, the crown  414  may be dome shaped. When the example first fluid  400  is substantially level, an amount of space between the first fluid  400  and the first portion  410  of the first top wall  408  is greater than an amount of space between the first fluid  400  and the second portion  412  of the first top wall  408 . As described in greater detail below, the first crown  414  provides a space for the first liquid  400  to flow into when the example cartridge  100  is rotating. 
     In the illustrated example, the second portion  412  of the first top wall  408  includes a first throat  416 . The example first throat  416  is in fluid communication with the first fluid chamber  210 . In the illustrated example, the first cap  134  is coupled to the first throat  416  to cover and/or seal an aperture  417  defined by the first throat  416 . When the example first cap  134  is removed, a sample and/or a liquid may be dispensed and/or removed (e.g., aspirated) from the first container  112  via the first throat  416 , a volume of the first liquid  400  may be determined via a tool (e.g., a pipettor) extending into the first fluid chamber  210  via the first throat  416 , etc. 
     In the illustrated example, the first baffle  212  and the second baffle  214  are positioned between the first bottom wall  208  and the first portion  410  of the first top wall  408 . The example first baffle  212  and the example second baffle  214  are a third height, which is less than the first height of the first portion  410  of the first top wall  408  and greater than the second height of the second portion  412  of the first top wall  408  relative to the first bottom wall  208 . Thus, the first baffle  212  and the second baffle  214  extend from the first bottom wall  208  into a space defined by the first crown  414  of the first top wall  408 . The first baffle  212  and second baffle  214  do not contact the first top wall  408 , and thus, the first baffle  212  and the second baffle  214  of the illustrated example are cantilevered from the first bottom wall  208 . 
     In the illustrated example, the third baffle  216  and the fourth baffle  218  are positioned between the first bottom wall  208  and the second portion  412  of the first top wall  408 . In the illustrated example, the third baffle  216  and the fourth baffle  218  are a fourth height, which is less than the second height of the second portion  412  of the first top wall  408 . The third baffle  214  and the fourth baffle  216  do not contact the first top wall  408  and, thus, the example third baffle  216  and the example fourth baffle  218  are also cantilevered from the first bottom wall  208 . In the illustrated example, the first baffle  212  and the second baffle  214  extend farther from the first bottom wall  208  than the third baffle  216  and the fourth baffle  216 . In some examples, the baffles  212 ,  214 ,  216 ,  218  are other heights relative the first bottom wall  208 . Also, in the illustrated example, the first bottom wall  208  is curved away from the first top wall  408  (e.g., concave relative to the top wall  408 ) to increase a fluid volume capacity and/or to minimize dead volume (e.g., volume not filled with fluid and, thus, not available for aspiration) of the first container  112 . In other examples, the first bottom wall  208  is other shapes (e.g., substantially straight or flat, etc.) 
     The second top wall  418  of the example second container  114  includes a third portion  420  defining a second crown  422  and a fourth portion  424  including a second throat  426 . In some examples, the second crown  422  is dome shaped. In the illustrated example, the third portion  420  of the example second top wall  418  is adjacent the third end wall  304  and the fourth portion  424  is adjacent the fourth end wall  306 . In the illustrated example, the second top wall  418  is stepped such that the third portion  420  of the first top wall  418  is the first height from the second bottom wall  308 , and the fourth portion  424  of the second top wall  418  is the second height, which is less than the first height from the second bottom wall  308 . When the example second fluid  402  is substantially level, an amount of space between the second fluid  402  and the third portion  420  of the second top wall  418  is greater than an amount of space between the second fluid  402  and the fourth portion  424  of the second top wall  418 . As described in greater detail below, the second crown  422  provides a space for the second liquid  402  to flow into when the example cartridge  100  is rotating. 
     In the illustrated example, the example second throat  426  is in fluid communication with the second fluid chamber  310  of the second container  114 . In the illustrated example, the first cap  133  is coupled to the second throat  426  to cover and/or seal an aperture  427  defined by the second throat  426 . When the example second cap  136  is removed, a sample and/or a liquid may be dispensed and/or removed (e.g., aspirated) from the second container  114  via the second throat  426 , a volume of the second liquid  402  may be determined via a tool (e.g., a pipettor) extending into the second fluid chamber  310  via the second throat  426 , etc. In the illustrated example, the second bottom wall  308  is curved away from the second top wall  418  (e.g., concave relative to the second top wall  418 ) to increase a fluid volume capacity of the example second container  114 . In other examples, the second bottom wall  308  is other shapes (e.g., straight or flat, etc.). 
     In the illustrated example, the fifth baffle  312  and the example sixth baffle  314  are cantilevered from the second bottom wall  308 . In the illustrated example, the fifth baffle  312  and the sixth baffle  314  are positioned between the second bottom wall  308  and the fourth portion  424  of the second top wall  418 . In the illustrated example, the fourth baffle  312  and the fifth baffle  314  are the fourth height and do not contact the second top wall  418 . In some examples, the baffles  312 ,  314  are other heights relative the second bottom wall  308 . 
       FIG. 5  is a cross-sectional view of the example cartridge  100  of  FIGS. 1-4  along line B-B of  FIG. 1  when the example cartridge  100  is rotating about the axis of rotation  106 . When the example cartridge  100  is rotating about the axis of rotation  106 , centrifugal forces urges the first liquid  400  and the second liquid  402  away from the axis of rotation  106 . In the illustrated example, the first container  112  is positioned on the platform  104  such that the first crown  414  is disposed farther away from the axis of rotation  106  than the first throat  416 . Similarly, the example second container  114  is positioned on the platform  104  such that the second crown  422  is positioned farther away from the axis of rotation  106  than the second throat  426 . As a result, when the example cartridge  100  rotates, the first liquid  400  flows around the baffles  212 ,  214 ,  216 ,  218  and into the space in the first fluid chamber  210  defined by first crown  414 , and the second liquid  402  flows around the baffles  312 ,  314  and into the space in the second fluid chamber  310  defined by the second crown  422 . As a result, the liquid  400 ,  402  is displaced such that the first surface  404  of the first liquid  400  and the second surface  406  of the second liquid  402  are slanted or angled relative to the horizontal but the first liquid  400  and the second liquid  402  do not flow into the first throat  416  and the second throat  426 , respectively, as the example cartridge  100  moves along the path  108  defined by the carousel  102 . In the illustrated example, a portion of each of the liquids  400 ,  402  is disposed between the first height and the second height during rotation of the example cartridge  100 . In addition, the extension of the first baffle  212  and the second baffle  214  into the first crown  414 , function to further mitigate bubble formation on the liquid in the first container  112  as the first container  112  is rotated and liquid is disposed into the first crown  414 . 
     In some examples, the cartridge  100  is periodically or aperiodically accelerated and decelerated as the cartridge  100  moves along the path  108 . As a result, the first liquid  400  and the second liquid  402  flow in and out of the spaces defined by the first crown  414  and the second crown  422 , respectively. The example baffles  212 ,  214 ,  216 ,  218 ,  312 ,  314  of the first container  112  and the second container  114  dampen or reduce the flow (e.g., sloshing) of the liquid  400 ,  402  as the liquid  400 ,  402  flows around the baffles  212 ,  214 ,  216 ,  218 ,  312 ,  314 . As a result, the baffles  212 ,  214 ,  216 ,  218  mitigate (e.g., reduce and/or minimize) bubble formation in the first liquid  400  and the second liquid  402 . In some examples, when the cartridge  100  decelerates to a stationary state, the first liquid  400  and the second liquid  402  flow from the spaces defined by the crowns  414 ,  422  to a substantially settled and/or level position (e.g., where the surfaces  404 ,  406  of the first liquid  400  and the second liquid  402  are substantially horizontal within approximately 100 to 300 milliseconds of the cartridge  100  being stationary. 
       FIG. 6  is a graph  600  illustrating a velocity of the example cartridge  100  over time. In the illustrated example, between a first time t 1  and a second time t 2 , the example cartridge  100  moves from a first position to a second position along the path  108 . In the illustrated example, the first position and the second position are approximately 180 degrees apart along the path  108 , and the second time t 2  is one second after the first time t 1 . Thus, in the illustrated example, the cartridge  100  moves 180 degrees around the example path  108  in one second. In other examples, the cartridge  100  moves other numbers of degrees (e.g., 45 degrees, 90 degrees, 360 degrees, etc.) in one second or in other amounts of time. 
     In the illustrated example, the cartridge  100  is in the stationary state (e.g., at a velocity of substantially zero) at the first time t 1  and at the second time t 2 . Thus, in some examples, the liquid  400 ,  402  is substantially level at the first time t 1 . Beginning at the first time t 1 , the example cartridge  100  accelerates from a velocity of approximately zero to a peak velocity (e.g., a maximum velocity of the cartridge  100  between the first time t 1  and second time) and then decelerates from the peak velocity to a velocity of approximately zero. In the illustrated example, the example cartridge  100  accelerates from a velocity of zero to the peak velocity in approximately 0.4 seconds. The example cartridge  100  then, in this example, decelerates from the peak velocity to a velocity of zero in approximately 0.6 seconds. Thus, the example cartridge  100  accelerates during an initial 40 percent of the movement of the cartridge  100  from the first position to the second position and decelerates during a latter  60  percent of the movement. In the illustrated example, between the first time t 1  and the second time t 2 , the example cartridge  100  substantially does not move at a constant velocity. 
     When the example cartridge  100  accelerates to the peak velocity, the first liquid  400  flows around the baffles  212 ,  214 ,  216 ,  218  and into the space in the first fluid chamber  210  defined by first crown  414 , and the second liquid  402  flows around the baffles  312 ,  314  and into the space in the second fluid chamber  310  defined by the second crown  422 . As a result, the liquid  400 ,  402  is displaced such that the first surface  404  of the first liquid  400  and the second surface  406  of the second liquid  402  are slanted or angled relative to the horizontal or otherwise not horizontal, but the first liquid  400  and the second liquid  402  do not flow into the first throat  416  and the second throat  426 , respectively, as the example cartridge  100  accelerates from the first position. 
     As the example cartridge  100  decelerates from the peak velocity, the fluid  400 ,  400  flows out of the spaces defined by the crowns  414 ,  422 , and the example baffles  212 ,  214 ,  216 ,  218 ,  312 ,  314  of the first container  112  and the second container  114  dampen or reduce the flow (e.g., sloshing) of the liquid  400 ,  402  as the liquid  400 ,  402  approaches and reaches a velocity of zero at the second time t 2 . The example baffles  212 ,  214 ,  216 ,  218  mitigate (e.g., reduce and/or minimize) bubble formation in the first liquid  400  and the second liquid  402  as the example cartridge  100  moves from the first position to the second position. As a result, after the cartridge  100  reaches the second position at the second time t 2  and, thus, is in the stationary state, the first liquid  400  and the second liquid  402  settle to a level position (e.g., where the surfaces  404 ,  406  of the first liquid  400  and the second liquid  402  are substantially horizontal) within, in this example, approximately 100 to 300 milliseconds after the second time t 2 . Thus, the baffles promote quick settling time. A faster settling time allows the carousel  102  holding the cartridge  100  to be rotated at a faster rate, which allows the system or analyzer into which these components are incorporated to achieve a higher throughput. Higher throughput improves lab productivity. 
     Also, as shown in  FIG. 6 , the motion curves are smooth and lack significant jerk (e.g., rates of change of acceleration/deceleration that may be illustrated with a velocity profile having transition points representing discontinuities in an acceleration profile). 
       FIG. 7  is a top, cross-sectional view of another example container  700  disclosed herein, which may be used to implement the example cartridge  100  of  FIG. 1 . In the illustrated example, the container  700  includes a first chamber  702  and a second chamber  704 . The example first chamber  702  is to be substantially empty (e.g., not filled with a liquid). A portion (e.g., ninety percent) of the volume of the example second chamber  704  is to be filled with a liquid such as, for example, a reagent, microparticles, one or more surfactants (e.g., a detergent), etc. Other examples have other shapes. 
     The example second chamber  704  is defined by a first sidewall  706 , a second sidewall  708 , a first end wall  710  and a second end wall  712 . The example first end wall  710  separates the first chamber  702  from the second chamber  704 . The first chamber  702  is defined by the first sidewall  706 , the second sidewall  708 , the first end wall  710  and a third end wall  714 . In the illustrated example, the container  700  has a rounded-rectangular perimeter shape, and the second chamber  704  has a substantially rounded-rectangular shape from the perspective of  FIG. 7 . 
     In the illustrated example, a first baffle  716 , a second baffle  718  and a third baffle  720  are disposed in the second chamber  704 . In the illustrated example, the baffles  716 ,  718 ,  720  are c-shaped and are oriented such that concave portions  722 ,  724 ,  726  of the baffles  716 ,  718 ,  720  face the axis of rotation  106  when the container  700  is positioned on the platform  104  via the cartridge  100 . The example baffles  716 ,  718 ,  720  are spaced apart from each other and the walls  706 ,  708 ,  710 ,  712  defining the second chamber  704 . 
       FIG. 8  is a perspective, cross-sectional view of the example container  700  along line C-C of  FIG. 7 . In the illustrated example, the baffles  716 ,  718 ,  720  extend from a bottom wall  800  of the container  700  toward a top wall  802  of the container  700 . The example baffles  716 ,  718 ,  720  do not contact the top wall  802 . In the illustrated example, the baffles  716 ,  718 ,  720  extend from the bottom wall  800  to a first height below the top wall  802  in the orientation of  FIG. 8 . 
     The example top wall  802  includes a first portion  804 , a second portion  806  and a third portion  808 . In the illustrated example, the first portion  804  and the third portion  808  of the top wall  802  are at a second height relative to the bottom wall  800  greater than the first height of the baffles  716 ,  718 ,  720 . The example second portion  806  of the top wall  802  is stepped from the first portion  804  and the third portion  808  to define a crown  810  having a third height greater than the first height and the second height. In the illustrated example, the second portion  806  of the top wall  802  is between the first portion  804  and the third portion  808 . In the illustrated example, the third portion includes a throat  812 , which is covered and/or sealed by a cap  814 . When the cap  814  is removed, a sample and/or a liquid (e.g., one or more reagents, surfactants, etc.) may be dispensed and/or aspirated via the throat  812 . 
     When the example container  700  is moved (e.g., accelerated and decelerated, for example, as illustrated in the graph  600  of  FIG. 6 ) along the path  108 , a liquid  816  (e.g., one or more reagents, surfactants, etc.) disposed in the second chamber  704  flows around the baffles  716 ,  718 ,  720  and in and out of a space defined by the crown  810  without flowing out of the container  700  via the throat  812 . The example baffles  716 ,  718 ,  720  dampen the flow (e.g., sloshing) of the liquid  816  to mitigate (e.g., reduce and/or minimize) bubble formation in the liquid  816  and enable the liquid  816  to quickly settle (e.g., within 100-300 milliseconds) once the example container  700  decelerates to a stationary state. 
     One or more of the features, in whole or in part, of the containers  112 ,  114  in  FIGS. 1-5  and the features in the container  700  of  FIGS. 7 and 8  may be used in addition to or as an alternative to one or more of the features of one of the other containers. 
     A flowchart representative of an example method is shown in  FIG. 9 . Although the example method is described with reference to the flowchart illustrated in  FIG. 9 , many other methods may alternatively be used. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, or combined. 
     The example method  900  of  FIG. 9  begins by rotating a container (e.g., the first container  112 ) about an axis of rotation such as, for example, the axis of rotation  106  of the carousel  102  (block  902 ). In some examples, the container moves from a first position to a second position via an acceleration or motion profile illustrated in the example graph  600  of  FIG. 6 . During rotation, liquid in the container  112  is displaced around a baffle (block  904 ). For example, the first liquid  400  in the first container  112  flows in a space between the first baffle  212  and the first sidewall  200 , a space between the first baffle  212  and the second sidewall  202 , and/or a space between the first baffle  212  and the first top wall  408 . The baffles  212 ,  214 ,  216 ,  218  dampen the flow (e.g., sloshing) of the first liquid  400  to mitigate (e.g., decrease and/or substantially minimize) bubble formation in the first liquid  400 . 
     The example process  900  also includes projecting or displacing the liquid into a crown of a top wall of the container (block  906 ). For example, the liquid  400  of the first container  112  is displaced into the first crown  414  during rotation. As a result, the first liquid  400  is prevented from flowing into the first throat  416  and out of the first container  112 . The example process  900  also includes ceasing rotation of the container (block  908 ). In some examples, the baffles  212 ,  214 ,  216 ,  218  enable the first liquid  400  to settle after the rotation is ceased in approximately 100 to 300 milliseconds. The process  900  may also include, in some examples, aspirating a portion of the liquid (block  910 ), and then the process  900  may end or start over with rotation of the container about the axis (block  902 ) 
     Although certain example methods, apparatus and articles of manufacture have been disclosed herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the claims of this patent.