Abstract:
A rinsing and drying apparatus of a clinical analyzer probe drain station is provided. The rinsing and drying apparatus has a group of nozzles that are offset from a longitudinal axis of a probe passage and may be inclined and oriented to provide tangentially oriented fluid-jet trajectories exiting into the sample probe passage. The offset nozzles, nozzle orientation, and cavity geometrical features of the device permit the drying capacity of probe-impinging planar air-knife jets to be maximized by stabilizing local internal fluid movement to form a swirling (e.g., helical) gas flow field directed away from a drying region and toward a vacuum exhaust. The rinsing and drying apparatus eliminates rinse water re-circulated entrainment and up-wash (spitting) during the air-knife drying operation. Therefore, the rinsing and drying apparatus significantly reduces water carryout on sampling probes thereby reducing sample/reagent dilution.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application Ser. No. 61/263,075 entitled “PROBE EXTERIOR RINSE AND DRYING DEVICE FOR A CLINICAL ANALYZER” filed on Nov. 20, 2009, the disclosure of which is hereby incorporated by reference in its entirety herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to apparatus, systems, and methods adapted for rinsing and drying of sample probes in clinical chemical analyzers. 
       BACKGROUND 
       [0003]    Handling of liquid samples, reagents, and other liquids is an essential part of the implementation of automated clinical chemistry test methods. Precision sample probes are used to aspirate and/or dispense these liquids in conventional clinical chemistry analyzers. For economy, sample probes are reused. Accordingly, sample probes are automatically cleansed, rinsed, and dried at a cleansing and rinsing station (a.k.a. a drain station) within conventional clinical chemistry analyzers. This is intended to limit an extent of carry-over of a previous sample and/or reagent artifacts (“carry-over”) or carry-over of rinse water that may dilute samples and/or reagents (“dilution”). Such carry-over and/or dilution may affect an accuracy of the clinical tests being performed on a sample. 
         [0004]    The tasks carried out by a conventional chemical analyzer drain station are: (1) to clean and rinse the sample probe(s) that will be used to access the sample and/or reagent so as to minimize carry-over, and thereafter (2) to dry the sample probe(s) to make the sample probe(s) ready for reuse on a next sample or next sample test sequence. 
         [0005]    Improvement of the effectiveness of such drain stations may improve the accuracy of tests performed by the clinical chemistry analyzer. Accordingly, there is a need to improve the effectiveness of the cleansing, rinsing, and drying processes carried out by clinical chemistry analyzer drain stations. 
       SUMMARY 
       [0006]    In one aspect, the present invention provides a sample probe rinsing and drying apparatus. The sample probe rinsing and drying apparatus includes a drain station body defining a rinsing well adapted to contain a rinsing liquid, and defining a nozzle recess; and a nozzle insert received in the nozzle recess to form a first annulus, the nozzle insert having a probe passage formed along a longitudinal axis, the probe passage adapted to receive the sample probe therein, and at least two nozzles having entries at the first annulus and exits at the probe passage, each of the at least two nozzles having a central axis that is offset from the longitudinal axis. 
         [0007]    According to another aspect, the present invention provides a sample probe rinsing and drying system. The system includes a pressurized fluid source; a drain station body defining a rinsing well and nozzle recess; and a nozzle insert received in the nozzle recess to form a first annulus, the nozzle insert having a probe passage formed along a longitudinal axis adapted to receive a sample probe therein, and at least two nozzles having entries at the first annulus and exits at the probe passage, each of the at least two nozzles being oriented and configured to direct a flow of fluid into the probe passage, wherein a portion of each flow of fluid from the nozzles contacts the probe and the remaining portions of each flow of fluid together form a substantially helical flow field within the probe passage. 
         [0008]    In another aspect, the present invention provides a method of rinsing and drying a sample probe. The rinsing and drying method includes lowering the sample probe through a probe passage and into a rinsing well; providing a substantially helical flow of fluid to the probe passage and around the sample probe; and withdrawing the sample probe from the rinsing well wherein rinsing liquid is removed from the sample probe by gas jet impingement and the substantially helical flow. 
         [0009]    According to another method aspect, a method of rinsing and drying a sample probe is provided. The rinsing and drying method includes lowering the sample probe along a longitudinal axis of a probe passage and into a rinsing well including rinsing liquid; providing a flow of fluid into a substantially cylindrical annulus surrounding the probe passage; directing the flow of fluid from the substantially cylindrical annulus through at least two nozzles and into the probe passage and around the sample probe wherein the flow of fluid from each of the at least two nozzles has a central axis that is offset from the longitudinal axis relative to a horizontal axis coincident with the longitudinal axis; and withdrawing the sample probe from the rinsing well wherein the rinsing liquid is removed from the sample probe by impingement and gas-jet wiping by a substantially helical flow created by the offset. 
         [0010]    Still other aspects, features, and advantages of the present invention may be readily apparent from the following detailed description illustrating a number of exemplary embodiments and implementations, including the best mode contemplated for carrying out the present invention. The present invention may also be capable of other and different embodiments, and its several details may be modified in various respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. The drawings are not necessarily drawn to scale. The invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The invention will be better understood by referring to the detailed description taken in conjunction with the following drawings. 
           [0012]      FIG. 1  is a partially cross-sectioned side plan view diagram of a sample probe rinsing and drying system according to the prior art. 
           [0013]      FIG. 2A  is a perspective view diagram of the fluid-containing passages and cavities of a sample probe rinsing and drying apparatus according to embodiments of the prior art. 
           [0014]      FIG. 2B  is a side view diagram of the fluid-containing passages and cavities of the sample probe rinsing and drying apparatus of  FIG. 2A  according to embodiments of the prior art. 
           [0015]      FIG. 3A  is a cross-sectioned perspective view of a rinsing and drying apparatus according to embodiments of the present invention. 
           [0016]      FIG. 3B  is a partial cross-sectioned perspective view of a nozzle insert received in a nozzle recess according to embodiments of the rinsing and drying apparatus of the present invention. 
           [0017]      FIG. 3C  is an exploded perspective view of the rinsing and drying apparatus of  FIG. 3A . 
           [0018]      FIG. 3D  is a perspective view illustrating a nozzle insert according to embodiments of the present invention. 
           [0019]      FIG. 3E  is a cross-sectioned perspective view illustrating the nozzle insert of  FIG. 3D . 
           [0020]      FIG. 3F  is a perspective view diagram of the fluid-containing passages and cavities of the improved sample probe rinsing and drying apparatus according to embodiments of the invention. 
           [0021]      FIG. 3G  is a side view diagram of the fluid-containing passages and cavities of the improved sample probe rinsing and drying apparatus of  FIG. 3A . 
           [0022]      FIG. 3H  is a top view diagram of the fluid-containing passages and cavities of the improved sample probe rinsing and drying apparatus of  FIG. 3A . 
           [0023]      FIG. 3I  is a top view diagram of the flow patterns within the fluid-containing passages and cavities of an embodiment of the sample probe rinsing and drying apparatus of the invention. 
           [0024]      FIG. 3J  is a top plan view diagram of a rinsing and drying apparatus according to embodiments of the present invention. 
           [0025]      FIGS. 3K and 3L  are left and right side perspective views, respectively, of the embodiment of rinsing and drying apparatus of  FIG. 3J  according to the present invention. 
           [0026]      FIGS. 3M and 3N  are cross-sectioned top views of the rinsing and drying apparatus taken along section lines “ 3 M- 3 M” and “ 3 N- 3 N” of  FIGS. 3K and 3L , respectively. 
           [0027]      FIG. 4  is a top view diagram of fluid-containing passages and cavities of another embodiment of a sample probe rinsing and drying apparatus. 
           [0028]      FIG. 5  is a left side perspective view of a rinsing and drying system according to embodiments of the present invention. 
           [0029]      FIG. 6  is a flow chart illustrating a method according to embodiments of the present invention. 
           [0030]      FIG. 7A  is a graph illustrating performance of a method according to the prior art. 
           [0031]      FIG. 7B  is a graph illustrating a performance of a method according to embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    In view of the foregoing difficulties and propensity for inaccurate results due to possible carry-over and/or dilution, there is an unmet need to improve the effectiveness of existing rinsing and drying apparatus and systems (drain stations) in terms of effectiveness of rinsing and/or drying of a sample probe. To address this need, embodiments according to aspects of the present invention provide improved nozzles, improved rinsing and drying apparatus, improved sample probe rinsing and drying systems, and improved rinsing and drying methods. The rinsing and drying apparatus and system may improve dilution by up to about 15 times, and may improve results&#39; precision by at least about 2 times as compared to prior clinical chemistry analyzers. 
         [0033]      FIG. 1  illustrates a portion of a clinical analyzer  100  according to the prior art that includes a conventional rinsing and drying apparatus  102  (otherwise referred to as a “drain station”). The rinsing and drying apparatus  102  has two locations for the probe  104  to enter, namely a cleansing well  106  and the rinsing well  108 . Each well  106 ,  108  is bottom-fed from respective cleansing liquid source  110  and rinsing liquid source  112 . Cleansing liquid is supplied to cleansing well  106  from the cleansing liquid source  110  through distributor  111  and passage  114  formed in the drain station body  116  to provide a static cleansing bath. Rinsing liquid is supplied to the rinsing well  108  from rinsing liquid source  112  through distributor  111  and passage  118  to provide a rinsing bath. A vacuum overflow feature is provided that maintains predetermined fluid height within the wells  106 ,  108 , removes waste, and exhausts all air and liquid entering the wells  106 ,  108 . A suitable vacuum source  120  is coupled to (coupling is not shown) exhaust ports  122 ,  124  interfacing with each of the wells  106 ,  108  at a predetermined well height and carries the exhausted liquids, other materials, and air to a drain. 
         [0034]    The cleansing well  106  may typically hold either sodium hypochlorite or sodium hydroxide cleaning liquids, and the rinsing well  108  may hold water. A robot  126  causes the sample probe  104  to move in two or more coordinate directions (e.g., vertical and horizontal). Accordingly, the probe  104  may aspirate sample, reagent, or other liquid at a first location with an aspirator/dispenser unit  128  and move the sample, reagent, or other liquid contained in the probe  104  to a second location and dispense the sample, reagent, or other liquid. Optionally, or in addition, rinsing liquid from the rinsing liquid source  112  may be dispensed by the aspirator/dispenser  128  through the sample probe  104  to rinse an interior of the sample probe  104 . 
         [0035]    At the top end of the rinsing well  108 , a nozzle assembly  130  is provided. The nozzle assembly  130  has two sets of nozzle features therein. The features are an air-knife feature  132  and a shower feature  134 . The nozzle features  132 ,  134  direct multiple air and water jets to wash and dry the sample probe  104  received in the rinsing well  108 , respectively. The geometry and structure of the nozzle features  132 ,  134  of a conventional nozzle coupled with the geometry of the rinsing well  108  of the rinsing and drying apparatus  102  produces a high degree of turbulent recirculation. Consequently, this results in unpredictable behavior of water droplet trajectories and water droplet deposition onto the surface of the sample probe  104  during the process of withdrawing and drying the probe  104  after rinsing well immersion. 
         [0036]    The rinsing and drying apparatus  102  functions within the following typical sequence. The sample probe  104  is lowered by robot  126  into the cleansing well  106  to soak the exterior surfaces thereof. Cleansing solution may be aspirated by aspirator/dispenser  128  into the probe  104  to soak the interior surfaces of the probe  104 . The probe  104  is withdrawn from the cleansing well  106  by robot  126  and repositioned over the rinsing well  108 . The probe  104  is lowered by robot  126  into the rinsing well  108 . The probe  104  and the upper section of the rinse well  108  may be showered with water (via shower feature  134 ) from rinsing liquid source  112 . Rinsing solution may be flushed through the interior of the probe  104  using aspirator/dispenser  128 . Rinsing solution is pumped into the bottom of the rinsing well  108  to flush and replenish the static rinsing bath. The probe  104  is withdrawn by robot  126  from the rinsing well  108  while the air-knife jets attempt to wipe away remaining water droplets from the outer surface of the probe  104  (via air-knife feature  132 ). 
         [0037]    However, the inventors herein have discovered that rinsing liquid “carryout&#39; and “spitting” effects occur in the operation of such conventional rinsing and drying apparatus and systems. Such effects are a consequence of the turbulence induced by internal cavity geometry of the rinsing well  108 , as well as air-jet nozzle design and configuration.  FIGS. 2A and 2B  illustrate the geometry of the cavities and fluid-containing passages of the shower feature  134  and the air-knife feature  132  with the body  116  not being shown for clarity. Passages  136 A,  136 B provide air from an air supply  136  ( FIG. 1 ) to the air-knife feature  132 . The air-knife feature  132  includes a first air knife  132 A and a second air knife  132 B positioned at the right and left sides of the upper portion of the rinsing well  108 . The rectangular-shaped reservoir  138  of the rinsing well  108  includes a generally rectangular cross section at various horizontal cross-sections thereof. The first air knife  132 A and second air knife  132 B are oriented to pass respective opposing planar air jets onto the exterior surface of the probe  104  as the probe  104  is withdrawn from the upper portion  138  of the rinsing well  108  by the robot  126 . This is intended to strip away any rinsing liquid or sample material remaining on the sample probe  104 . However, as will be seen below, this stripping action may be less then optimal. 
         [0038]    Shower feature  134  is positioned below the air-knife feature  132  and includes generally-orthogonal passages  134 A,  134 B, etc. that generally surround the upper portion of the rinsing well  108 . The shower feature  134  is operable to spray jets of water from a plurality of rinse jet passages positioned in fluid communication with the passages  134 A,  1348 , etc. onto the exterior surface of the probe  104  and onto the interior of the rectangular-shaped reservoir  138  of the rinsing well  108 . The rinsing liquid is collected into a rectangular-shaped reservoir  138  of the rinsing well  108  that is located below the shower feature  134 . The rinsing liquid ejected from the shower feature  134  and any material removed from the probe  104  is evacuated through the vacuum exhaust port  122 . 
         [0039]    During the idle mode of operation when the shower feature  134  and air-knife feature  132  are not operating and only flow to the vacuum port  122  is provided, air entering the sudden expansion of the rectangular-shaped reservoir  138  of the rinsing well  108  from atmosphere re-circulates in the rectangular-shaped reservoir  138 , principally as a pair of large, standing, counter-rotating vortices. These counter-rotating vortices entrain any remaining water from the well walls, shower feature  134 , and the rinsing well bath of the rectangular-shaped reservoir  138  of the rinsing well  108 . This effect is amplified when the air-knife feature  132  is operable due to the increased volumetric air flow and velocity from the two opposed, inclined planar air-knife jets used to dry the sample probe  104 . Moreover, as the sample probe  104  is withdrawn, the air-knife jets may merge; directly impacting the surface of the rinsing well static bath to create an up-wash of rinsing liquid (e.g., water) into the vertical flow field. This liquid is propelled into the underside of the jets of the air-knife feature  132  and then onto the probe  104 . These fluid flow dynamics lead to a high propensity for ejection of rinsing liquid droplets from the drain system (spitting), carryout of the rinsing liquid on the probe  104 , and, consequently, sample and/or reagent dilution and propensity for less accurate analytical results because of such dilution. 
         [0040]    Thus, there remains a need for a structure of a rinsing and drying apparatus (e.g., drain station) that produces more effective fluid dynamical behavior, such as controlled fluid-to-structure interaction and jet-to-probe impingement interaction for probe drying operations. In particular, it is desired that a fluid flow is created in the upper portion of the rinsing well so that the above-mentioned problems of spitting and/or carryout are minimized or eliminated. 
         [0041]    These and other aspects and features of the invention will be described with reference to  FIGS. 3A-7B  herein. 
         [0042]    Referring now to  FIG. 3A , an improved rinsing and drying system  300  is illustrated according to embodiments of the invention. The invention provides improved geometry of the upper portion of the rinsing well and/or of the air-knife feature that may enable relatively more efficient execution of the final drying step of the rinsing and drying sequence. The reservoir geometry within the upper portion of the rinsing well and the improved geometry/configuration of the air-knife feature of the present invention improve the overall fluid dynamics and fluid-structure interaction to enable relatively more effective probe drying, as well as direct removal of all liquids and other material to a vacuum exhaust port. 
         [0043]    More specifically, to generate reliable fluid-structure interaction for probe-drying operations (planar jet-to-probe impingement) and stabilized internal fluid dynamics (e.g., little or no recirculation) for an improved rinsing and drying apparatus, specific geometrical features were developed. In a first aspect, a group of two or more nozzles (e.g., inclined nozzles) are oriented with a horizontal offset from a longitudinal axis of a probe passage that is adapted to receive the sample probe. In a second aspect, the probe passage shape is improved. In another aspect, a shape of the reservoir below the probe passage is improved. One or more of these features may produce improved dynamic fluid motion that functions to produce a relatively more stable swirling flow field and improve the gas-jet wiping of the liquid from the probe for effective sample probe drying. 
         [0044]    Referring now to  FIGS. 3A-3N , an embodiment of the present invention will now be described. According to an aspect of the invention, a sample probe rinsing and drying apparatus  300  is provided. The sample probe rinsing and drying apparatus  300  includes a drain station body  302  defining a rinsing well  304  adapted to contain a rinsing liquid  305  (depth of the rinsing liquid  305  shown dotted), and a nozzle recess  306 . The nozzle recess  306  may include a number of steps at different diameters. The drain station body  302  may be manufactured from any suitable polymeric material, such as an acrylic material. Other suitable materials may be used. A nozzle insert  308  is received in the nozzle recess  306 , and the structure of the nozzle insert  308  and recess  306  cooperate to form a first annulus  310 . The nozzle insert  308  has a probe passage  312  formed along, and preferably centered on, a longitudinal axis  314 . The probe passage  312  is adapted to receive a sample probe  316  therein (sample probe  316  shown in phantom lines). The apparatus  300  further includes at least two nozzles  318 ,  320  having entries  318 A,  320 A, at the first annulus  310  and exits  318 B,  320 B at the probe passage  312 . Each of the nozzles  318 ,  320  includes a central axis  318 C,  320 C located at the geometrical center thereof that is offset from the longitudinal axis  314  in a horizontal direction  321 A (See  FIG. 3H ). The nozzles  318 ,  320  and the first annulus  310  make up the air knife feature  325 . 
         [0045]    In the depicted embodiment, the rinsing well  304  includes a lower well portion  304 L having a substantially cylindrical shape; the lower well portion  304 L extending in an orientation that is substantially vertical and substantially parallel with the longitudinal axis  314 . The rinsing well  304  may include an upper well portion  304 U below the nozzle recess  306 , having at least a portion that has a larger transverse dimension than a transverse dimension (e.g., diameter) of the lower well portion  304 L. In the depicted embodiment, the upper well portion  304 U has a frustoconical shape providing a smooth transition to the substantially cylindrical lower well portion  304 L. In the illustrated embodiment, an exhaust port  322  is coupled to the lower well portion  304 L just below the upper well portion  304 U (see  FIG. 3B ). The exhaust port  322  has a central axis  322 C that may be oriented substantially tangentially to an outer wall of the lower well portion  304 L as shown in  FIGS. 3A ,  3 B, and  3 F- 3 I. 
         [0046]    The drain station body  302  may also include a cleansing well  323  that is positioned next to the rinsing well  304  and may contain a cleansing liquid. A cleansing well exhaust port  323 A may be provided adjacent to the cleansing well  323 . As with the exhaust port  322 , the exhaust port  323 A is used to evacuate used cleansing fluid and control the cleansing bath level. 
         [0047]    In more detail, each nozzle  318 ,  320  may be configured in a downwardly-angled orientation from the entries  318 A,  320 A with the central axis  318 C,  320 C of each nozzle  318 ,  320  being nonparallel with a substantially horizontal second axis  321 B that is perpendicular to the longitudinal axis  314  as shown in  FIGS. 3G and 3H  and also perpendicular to horizontal axis  321 A shown in  FIG. 3H . For example, the angle ø between the longitudinal axis  314  and each respective central axis  318 C,  320 C may be between about 30 degrees and 75 degrees, or even between about 45 degrees and 75 degrees, for example. Preferably, the angle ø for each nozzle  318 ,  320  is about equal. Other angles may be used. At the exits  318 B,  320 B of the nozzles  318 ,  320 , the probe passage  312  may be substantially cylindrical. In the depicted embodiment, the first annulus  310  comprises a cylindrical annulus. The cross-sectional shape of the annulus  310  may be square, rectangular, triangular, round, half round, or of other polygonal shapes. In the depicted embodiment, a v-shaped point is provided on the inner portion of the first annulus  310 . The nozzles  318 ,  320  are preferably rectangular in cross section and have a width of about 2 mm to about 4 mm and a thickness of about 0.1 mm to about 0.3 mm in cross section. 
         [0048]    In the depicted apparatus  300 , the fluid inlet port  324  to the annulus  310  has a central axis  324 C that is oriented substantially tangential to the annulus  310  (See  FIGS. 3F-3H ). In this way, the pressurized fluid is provided into the annulus  310  with relatively low fluid restriction. The nozzle insert  308  may also include first and second o-rings  326 A,  326 B received in grooves positioned above and below the annulus  310  (See  FIG. 3B ). The nozzle insert  308 , which may be manufactured from a titanium material or other corrosion-resistant material, may be inserted into the nozzle recess  306  in the drain station body  302 . The nozzle insert  308  may be retained in the nozzle recess  306  by pins  328  received through holes  329  and engaged with upper groove  330  (See  FIGS. 3C and 3E ). Pins  328  may be secured in holes  329  by a press fit or otherwise retained in holes  329  by mechanical fasteners, set screws, adhesive, weld, etc. 
         [0049]    The rinsing and drying apparatus  300  may include a second annulus  332  positioned below the first annulus  310 . The second annulus  332  may be formed by the cooperation of the geometry of the nozzle insert  308  and the nozzle recess  306  ( FIG. 3A ). The second annulus  332  is fluidly coupled to a plurality of shower passages  334  extending from the second annulus  332  to a lower portion  312 L of the probe passage  312  at a lower portion of the nozzle insert  308  (see  FIG. 3B ). The plurality of shower passages  334  and second annulus  332  make up the shower feature  335 . The lower portion  312 L may include a frustoconical portion. As installed, the upper portion of the rinsing well  304  and the lower portion  312 L of the probe passage  312  may cooperate to form a reservoir  336  into which the shower of rinsing liquid from the shower feature  335  may be directed. In the depicted embodiment, opposed frustoconical portions  312 L,  304 U form the reservoir  336 . However, other circular reservoir shapes without sudden expansion may be used. The frustocone angle should be no greater than about 45 degrees from the longitudinal axis  314 , for example. 
         [0050]      FIG. 3I  illustrates implementation of a swirling flow path produced around the sample probe  316  (shown in phantom lines) according to aspects of the invention. The geometry of the probe passage  312  may be generally cylindrical at the nozzle exits, and the fluid (e.g., air) may be introduced into the space between the outer wall  312 W of the probe passage  312  and the sample probe  316  by the first and second nozzles  318 ,  320 . The nozzles  318 ,  320  may be oriented to provide for fluid-jet trajectories that are generally tangential to the cylindrical wall  312 W of the probe passage  312 . The jets from the nozzles  318 ,  320  are not directly opposed, but are offset (e.g., equally offset) from the longitudinal axis  314  (shown as a dot) to cause the flows from each to swirl, interleave, and follow roughly parallel helical paths. As the fluid (e.g., air) exits the nozzles  318 ,  320 , a portion of each fluid jet impinges onto the sample probe  316 , while the remaining portion of each jet contributes mutually to the generation of a generally stable, swirling flow field around the sample probe  316 . Thus, the fluid flow has relatively high momentum and entrains any liquid on the surface of the sample probe  316  and any surrounding liquid (e.g., any liquid on the wall surface  312 W of the passage  312 ). A vacuum from a vacuum source  510  ( FIG. 5 ) is applied at the exhaust port  322  to collect and exhaust any liquid or other material swept from the sample probe  316  and walls  312 W. 
         [0051]    For example, the fluid (e.g., air) flow generally tangentially enters the first annulus  310  from the fluid inlet port  324  and may circle around the annulus  310  in a counterclockwise direction, for example. The fluid may then enter into the nozzles  318 ,  320  at their respective entries and then exit at their respective exits into the space between the wall  312 W and the sample probe  316 . Within the space, the fluid flow is swirling around the probe  316  at a relatively high rate of speed. The fluid (e.g., air) velocity in the space may be between about 10 m/s and about 50 m/s, for example. The flow rate may be about 10 to 20 liters per minute, for example. To the extent that the nozzles  318 ,  320  may include a downward orientation at their exits, the fluid flow may be both swirling about the sample probe  316 , and also downwardly oriented to produce a generally helical flow pattern. 
         [0052]      FIG. 4  illustrates another embodiment of a rinsing and drying apparatus  400  according to aspects of the invention. The geometry of the probe passage  412 , first annulus  410 , inlet port  424 , and exhaust port  422  are the same as before described. However, this embodiment includes three nozzles  418 ,  420 ,  421  that may be oriented to provide for fluid-jet trajectories that are generally tangential to the cylindrical wall  412 W of the probe passage  412 . As before, the central geometrical axes of each of the jets from the nozzles  418 ,  420 ,  421  are not directly opposed, but are offset (e.g., equally offset) from the longitudinal axis  414  (shown as a dot) to cause the flows from each nozzle to swirl, interleave, and follow roughly parallel helical paths. As the fluid (e.g., air) exits the nozzles  418 ,  420 ,  421 , a portion of each fluid jet impinges onto the sample probe  316 , while the remaining portion of each jet contributes mutually to a generally stable, swirling flow field around the sample probe  316 . Thus, the function is as heretofore described. Each of the nozzles  418 ,  420 ,  421  may be downwardly oriented as above described and, thus, may impart a substantially helical flow trajectory around the probe  316 . 
         [0053]    Now referring to  FIG. 5 , a rinsing and drying system  500  according to another aspect of the invention is disclosed. The system  500  includes a pressurized fluid source  502 , such as pressurized air. The air may be provided at a pressure of about 20 psi, for example. Other pressures may be used. Suitable conduits may connect to a distributor  504  and, thus, pressurized air may be provided to the air-knife feature  325 ,  425  (see  FIGS. 3B and 4 ) of the rinsing and drying apparatus  300 ,  400  in conduit  505 . The distributor  504  may be a suitable series of valves and passages adapted to selectively cause flow of the fluids and liquids to the various annulus and wells. The system  500  includes a drain station body  302 , and a nozzle insert  308 ,  408  as described above. As also before described, the nozzle insert  308 ,  408  includes a probe passage  312 ,  412  adapted to receive the sample probe  316 . 
         [0054]    In operation, the system  500  may include any suitable moving component(s) such as robot  506  for carrying out motion of the sample probe  316 . The robot  506  may include suitable robot components (e.g., one or more robot arms, beams, or gantries) to which the sample probe  316  may be mounted. Suitable motion may be imparted to the probe  316  by the robot  506 , such as one-axis, two-axis, or three-axis motion. The robot  506  may be actuated by commands from suitable controls  507 . 
         [0055]    In one embodiment, the sample probe  316  is first moved above and lowered into, and is at least partially immersed in, a cleansing well  323  by robot  506 . While immersed in the cleansing well  323 , the aspirator/dispenser  508  may draw some of the cleansing liquid into the interior of the probe  316  to cleanse same. Aspirator/dispenser  508  may be adapted, and operational, to control a level of pressure to draw in a desired amount of the sample fluid, reagent, cleansing liquid, etc. into the probe  316 , and also to control the dispensing operations performed by the probe  316 . The aspirator/dispenser  508  may include suitable pressure sensor(s), valve(s), accumulator(s), or other pneumatic or hydraulic components (not shown) to effectuate the liquid aspirating/dispensing action. Any suitable apparatus for drawing the fluid into the probe  316  may be used. For example, aspirating and dispensing systems that may be used with the present invention are described in U.S. Pat. Nos. 7,634,378; 7,477,997; and 7,150,190, which are hereby incorporated by reference herein. After cleansing the tip, the sample probe  316  may be withdrawn to the position of the exhaust port  323 A ( FIG. 3A ), and the cleansing liquid may be dispensed by aspirator/dispenser  508  into the exhaust port  323 A. The used cleansing liquid may then be exhausted in conduit  512  to a drain  510 A, for example. After cleansing, the cleansing liquid may be replenished from cleansing liquid source  507  through distributor  504  and conduit  513 . 
         [0056]    Following cleansing, the sample probe  316  may be moved above and lowered by the robot  506  through the probe passage  312 ,  412  and into the rinsing well  304  ( FIG. 3A ). The sample probe  316  may be either centrally located or slightly misaligned in the probe passage  312 ,  412 . In some embodiments, when the tip of the probe  316  is positioned adjacent to the exhaust port  322 , rinsing liquid from rinsing liquid source  509  may be dispensed by aspirator/dispenser  508  to rinse the interior of the probe  316 . The vacuum source  510  evacuates the used rinsing liquid into exhaust port  322  through conduit  512  and to drain  510 A. In some embodiments, the shower feature (e.g.,  335 ,  435 ) of the apparatus  300 ,  400  may be employed to receive rinsing liquid in conduit  511  from rinsing liquid source  509  and distributor  504  to rinse an exterior of the probe  316  as the probe  316  enters or is withdrawn from the probe passage  312 ,  412 . Suitable conduits  515 ,  513  may provide supplies of rinsing liquid and cleansing liquid from rinsing liquid source  509  and cleansing liquid source  507 , respectively, to the bottoms of the rinsing and cleansing wells  304 ,  323  (See  FIG. 3A ). 
         [0057]    After the probe  316  is rinsed, the probe  316  may be withdrawn from the rinsing well  304  and a flow of fluid (e.g., air) is provided in conduit  505  from pressurized fluid (air) source  502  through distributor  504  and conduit  505  to produce swirling fluid jets (e.g., air jets) onto the exterior of the probe  316 . During the fluid-jet (e.g., air-jet) drying operation, the fluid dynamics are substantially that of a turbulent swirling (helical) flow in the annular space between the probe  316  and the walls of the probe passage  312 ,  412 . Fluid motion during an idle mode of operation is also substantially stable; following a substantially direct trajectory from the probe passage  312 ,  412  to the exhaust port  322  with substantially little or no fluid-vortex (e.g., air-vortex) recirculation or rinsing liquid up-wash. 
         [0058]    Thus, in summary, the method of rinsing and drying a sample probe includes, as best represented in  FIG. 6 , lowering the sample probe through a probe passage and into a rinsing well in  602 , providing a substantially helical flow of fluid to the probe passage and around the sample probe in  604 , and withdrawing the sample probe from the rinsing well wherein rinsing liquid is removed from the sample probe by gas-jet impingement and the substantially helical flow in  606 . 
         [0059]      FIG. 7A  is a graph illustrating performance of a method according to the prior art. More specifically, the graph represents a plot of % Dilution vs. Sample Replicates. The scattered and somewhat randomly distributed analytical results show that the behavior of rinsing liquid droplet trajectories and deposition onto the sample probe using conventional methods is typically unpredictable and includes wide disparities in % Dilution from test to test. Additionally, the illustrated % Dilution is nominally between about 2% and about 6%. 
         [0060]    In operation, the described apparatus  300 ,  400  and system  500  produces a significant reduction in the unpredictable behavior of rinsing liquid droplet trajectories and deposition, which is reflected in more even and narrowly distributed analytical results (See  FIG. 7B ). Observed impact in controlled experiments is illustrated by the data in  FIG. 7B , which illustrates a plot of % Dilution vs. Sample Replicates. As is shown, sample/reagent dilution is reduced by up to about 15 times as compared to the prior art and, as a result, precision is increased by at about least 2 times. In particular, the % Dilution utilizing the improved apparatus  300 ,  400  and system  500  including a generally helical flow and improved air knife is dramatically reduced to a nominal % Dilution ranging between about 0.5% and about 1%. Moreover, the effect on % Dilution is amplified by the fact that most clinical analyzers may have multiple sample-reagent drains. 
         [0061]    The present invention may be advantageously utilized in connection with clinical analyzers, and is particularly useful for those having a semi-flexible sample probe that may require adequate rinsing passage clearance to accommodate uncertainty in robotic positioning. As will be appreciated, the present invention accommodates for probe offset in addition to producing a stable, generally helical flow field that improves probe drying. 
         [0062]    Having shown the preferred embodiment, those skilled in the art will realize many variations are possible that will still be within the scope and spirit of the claimed invention. Therefore, it is the intention to limit the invention only as indicated by the scope of the claims.