Abstract:
A cup assembly for holding a sample to be analyzed spectrochemically, including a sample cell having a generally cylindrical wall longitudinally extending between a first end and a second end thereof and a sleeve having a generally cylindrical wall longitudinally extending between a first end and a second end thereof, and a plurality of projections longitudinally extending from the first end of the sleeve wall. When a substantially planar film is interposed between the sample cell and the sleeve, and the first end of the sample cell is inserted into the first end of the sleeve, the film is retained between the sample cell and the annular sleeve; and the longitudinal projections are positioned to perforate the film when the film is pulled against the longitudinal projections.

Description:
RELATED APPLICATION  
       [0001]     This application claims priority of U.S. patent application Ser. No. 60/772,505, filed Feb. 10, 2006, entitled SAMPLE-CUP WITH THIN-FILM DETACHMENT MECHANISM, the entire disclosure of which is incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention relates to a sample cup for use in holding specimens for spectrochemical analysis, and more particularly to a sample cup comprised of a collar that pulls a thin-film material taut over the open end of cell body, thereby obstructing one end of the cell body and closing the sample cup.  
       BACKGROUND OF THE INVENTION  
       [0003]     The use and applications of thin-films to close substance containing sample cups are well recognized. An example of such a sample cup is disclosed in U.S. Pat. No. 5,630,989, entitled APPARATUS FOR TRIMLESS SAMPLE CUP USED IN X-RAY SPECTROSCOPY, the entire disclosure of which is hereby incorporated by reference herein.  
         [0004]     When a sheet of thin film material is positioned over the open end of a cell body by means of the annular collar or sleeve, one or more portions of the thin film material extend beyond the collar. These excess portion(s) of the thin film may have a tendency to flare away from the sides of the cell body. As such, the excess thin film material must typically be trimmed from the sides of the cell body, in order that the sample cup may be conveniently handled.  
         [0005]     Further, to ensure proper accommodation and precise positioning in sample cup holding instrumentation, extraneous thin-film surrounding the assembled sample cup must typically be meticulously trimmed very close to the sample cup cell body. Residual thin-film portions remaining attached to the sample cup may lead to sample cup misalignment in instrumentation. Alignment inaccuracies potentially affect the analytical accuracy of spectroscopy and analysis.  
         [0006]     Heretofore, the conventional method of trimming excess thin-film has been with the use of scissors. This is a detailed, time-consuming procedure for an analyst, especially when one considers that thin films are inherently prone to static electrical charge build-up. The thin-film clippings are typically annoyingly troublesome—as they cling to virtually any nearby surface, including the thin-film remaining attached to the sample cup. This potentially alters the transmission effects of radiation though the thin film window, in turn adversely affecting the spectrochemical analysis. In instances that dictate a relatively large number of sample preparations and throughput, applying a scissors to trim the extraneous thin-film is not a practical approach.  
         [0007]     In response to this need, a sample cup integrated with a mechanism for detaching thin-film portions near the sample cup cell is desired. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     Understanding of the present invention will be facilitated by considering the following detailed description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings, in which like numerals refer to like parts, and:  
         [0009]      FIG. 1  illustrates a sample cup cell and sleeve incorporating a serrated edge;  
         [0010]      FIG. 2  illustrates the sample cup cell and sleeve of  FIG. 1  with a film interposed there between;  
         [0011]      FIG. 3  illustrates the sample cup cell and sleeve of  FIG. 1  with the sleeve advanced over the film and cell;  
         [0012]      FIG. 4  illustrates the sample cup cell and sleeve of  FIG. 1  with the sleeve advanced over the film and cell and portion(s) of the film being removed;  
         [0013]      FIGS. 5 and 6  illustrate the sample cup cell and sleeve of  FIG. 1  with the sleeve advanced over the film and cell and portion(s) of the film removed;  
         [0014]      FIG. 7  illustrates a sample cup cell and sleeve incorporating a serrated edge, and  
         [0015]      FIG. 8  illustrates a cross-sectional view of an embodiment of a sample cup sell, a collar and a sleeve incorporating a serrated edge. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]     It is to be understood that the figures and descriptions have been simplified to illustrate elements that are relevant for a clear understanding of the present invention, while eliminating, for the purpose of clarity, many other elements found in typical sample cups and methods of making and using the same. Those of ordinary skill in the art may recognize that other elements and/or steps are desirable and/or required. However, because such elements and steps are well known in the art, and because they do not facilitate a better understanding of the present invention, a discussion of such elements and steps is not provided herein.  
         [0017]     Referring now to  FIG. 1 , there is shown a sample cup assembly  100 . In the illustrated embodiment, sample cup assembly  100  includes a main cell body  110 , a substantially planar thin film material  200  (see,  FIGS. 2-6 ) and an annular collar or sleeve  120 . Sleeve  120  may take the form of a collar, snap-on ring, sleeve or any other device of similarity, to firmly affix thin-film  200  over the cell  110  opening. The cell  110  window ( 210 ,  FIG. 5 ) formed by thin-film  200  represents the point of entry for irradiating a sample substance within the cell  110  for spectrochemical analysis. Cell  110  and sleeve  120  may each be formed of plastic, for example. In one particular embodiment, they are around 1.20-1.23 inches in diameter, have an internal aperture of around 0.95-0.97 inches and are around 0.8-1 inch tall. Of course, other sizes are contemplated. Further, sleeve  120  may optionally be considerably shorter than the cell (as is shown in the embodiment of  FIG. 7 ).  
         [0018]     Referring again to  FIG. 1 , cell  100  includes a side-wall portion  112  extending longitudinally an open end of cell  100  and an end portion  114 . A flange  116  is positioned around end portion  114 . The side-wall and end portions  112 ,  114  define an open-ended inner cavity, or hollow. Similarly, sleeve  120  includes a side-wall portion  122  extending longitudinally between open ends  124 ,  126 . A flange  128  is positioned around open end  126 . Open-end  124  of sleeve  120  is adapted to receive the open end of the cell  110 .  
         [0019]     By way of further non-limiting example only, apparatus  100  may optionally exhibit many of the features presented by the afore-incorporated U.S. Pat. No. 5,630,989. For example, cell body  110  may define a sample retaining region and a reservoir region. The sample retaining region of cell body  100  may be tubular in shape having an open end and a closed end defined by side-wall portion  112  and end portion  114 . Side-wall  112  may be generally cylindrical and longitudinally extend from the closed end up to the open end. As such, side-wall  112  and end-portion  114  define a hollow capable of retaining a sample specimen (not shown). The outside of side-wall  112  may be tapered toward the open end of the sample retaining region. The edge of the side-wall  112  proximate the open end may be rounded or squared.  
         [0020]     If incorporated, a taper of the side-wall  114  ends at the reservoir region  840  (in  FIG. 8 ) defined by flange  116 . The reservoir region surrounds and extends below the closed end  114  of the sample retaining region. A venting provision may be disposed within the closed end. The venting provision may be optionally ruptured, thereby allowing the interior hollow of cell body  110  to communicate with the reservoir region. As such, any sample contained within the sample retaining region hollow can be vented to the reservoir region.  
         [0021]     Annular collar or sleeve  120  is useful for properly positioning the thin film material across the opening of cell body  110 . Sleeve  120  is generally tubular having first and second, oppositely disposed open ends. Side-wall  122  may have an interior surface that is tapered at an angle of inclination supplementary to the angle of inclination of the outside of side-wall  112  of cell body  110 . One or more projections and mating recesses may be used to couple cell body  110  to sleeve  120 . For example, one or more ring projections and matching ring recesses may circumnavigate side-walls  112 ,  122 .  
         [0022]     According to an aspect of the present invention, sleeve  120  incorporates a series of projections  118  on an outermost edge  113  of side-wall  122  proximate open end  124  thereof. Projections  118  may be sharp or blunt, for example. Projections  118  may be adapted to both perforate or puncture thin film  200  ( FIGS. 2-6 ), and secure a remaining portion of thin film  200  ( FIGS. 2-6 ) after perforation, thereby closing the open end of the cell  100  interior hollow. Projections  118  may be regularly (or irregularly) spaced along the edge  113 . It is also understood that the projections may be more blade shaped in terms of a knife edge that gradually extends in height about the circumference of the sleeve.  
         [0023]     Referring again to  FIG. 2 , in use thin film  200  is interposed between cell body  110  and the protrusions  118  of sleeve  120 . Thin film  200  is positioned over the open end of cell body  100 . According to an embodiment of the present invention, thin film material  200  is flexible and transparent to radiant energy used in spectrochemical analysis. The possible compositions of such thin film materials  200  are well known in the art and need not be set forth herein at length. Projections  118  collectively represent foci for perforating thin-film  200  for subsequent detachment from the assembled sample cup. Sleeve  120  is positioned over film  200  and around cell body  110 . Sleeve  120  and cell body  110  may mate in a conventional manner using one or more projections and one or more receiving portions, such as conventional tabs and recesses, for example. The cell/film/sleeve assembly may optionally be inverted after mating to aid in thin film trimming.  
         [0024]     Referring to  FIGS. 3 and 4 , by pulling the extraneous portion(s) of thin-film  200  against projections  118 , a substantially uniform line of perforations in film  200  is created substantially conforming to the configuration of the securing collar or sleeve  120 . In the illustrated embodiment, cell body  110  and sleeve  120  are circular in cross-section, although other configurations can be used. With increasing force, thin-film  200  breaks away in an intact circular pattern defined by the perforations.  
         [0025]     Referring now also to  FIGS. 5 and 6 , thin-film detachment is at the juncture of the upper end of the collar, sleeve or snap-on ring  120  and closely intimate to the assembled sample cup cell  100 . This facilitates the unobstructed alignment of the assembled sample cup in instrumentation sample cup holders, thereby averting any ramifications of any residual thin-film remaining attachment.  
         [0026]     Referring now also to  FIG. 7 , there is illustrated another embodiment of the invention. Sampling cup assembly  100  thereof again includes a sample cup cell body  110  and a snap-on ring or sleeve  120 . The edge of the snap-on ring or sleeve  120  again incorporates projections  118 . In the embodiment of  FIG. 7 , the length or height of the snap-on ring or sleeve  120  is substantially smaller than the length of the sample cup cell  100 . The ring recess mentioned earlier may be in the form of a continuous semicircular groove  710  disposed in the side-wall  112 . The semicircular groove may be continuous across the side-wall  112  or it may be segmented. The ring projection mentioned earlier may be a semicircular protrusion  720  disposed on the inner surface of the side-wall  122 . The semicircular protrusion  720  may be continuous across the side-wall  122  or it may be segmented. When the cell body  110  is inserted in the end of the sleeve  120 , the slight interference fit between the side-wall  122  and the sleeve  120  increases the tautness of a film  200  (in  FIGS. 2-6 ) interposed between the cell body  110  and the sleeve  120 . The protrusion(s)  720  lodge(s) into the groove  710  and secures the sleeve  120  to the cell body  110  while maintaining the tautness in the film  200  across the open end of the cell body  110 .  
         [0027]     In an embodiment of the invention, a portion  715  of the cell body  110  above the groove  710  may be frustoconical in shape converging towards the first end of the sample cell body  110 . Correspondingly, the ring or sleeve  120  may also be frustoconically shaped such that it converges from the first end  124  of the sleeve  120  to the second end  126  of the sleeve  120 .  
         [0028]     Now referring to  FIG. 8 , another embodiment of the invention is illustrated. A collar  810  is further included and used to initially secure a film  200  to the sample cell body  110  along the side-wall  112 . A sample is then placed on film  200 . The sample may be a powder or liquid droplet for example. Another film  820  is then placed across the open end of the sample cell body  110 , over film  200  and the sample such that the sample is sandwiched between the two film layers. The snap-on ring  120  is locked to the sample cell body  110  via ring recess(es) and ring protrusion(s). The collar  810  and the snap-on ring  120  cooperatively hold the films  200 ,  820  tautly against the open end of the sample cell body  100 .  
         [0029]     Those of ordinary skill in the art may recognize that many modifications and variations of the present invention may be implemented without departing from the spirit or scope of the invention. Thus, it is intended that the present invention covers the modifications and variations of this invention.