Abstract:
A fluidic coupling device includes a housing, and a piston, spring, and cap insertable in the housing. The spring includes a stack of spring washers and is compressible between the cap and the the piston. The cap is threadedly engageable with the housing and movable into contact with the spring. The device may be coupled to a component in a sealed manner by inserting a ferrule between the piston and the component, inserting a conduit through the housing and into the component, and threadedly engaging the housing with the component, thereby compressing the spring and translating the piston against the ferrule. The device may enable coupling to be done manually, with minimal variation in compressive loading. The piston and spring may desensitize the device to thermal cycling effects, reducing the need for retightening.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/761,410, filed Feb. 6, 2013, titled “FLUIDIC COUPLING DEVICES, ASSEMBLIES, AND RELATED METHODS,” the content of which is incorporated by reference herein in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates generally to fluidic couplings, particularly fluidic couplings entailing the use of ferrules. 
       BACKGROUND 
       [0003]    Ferrules may be utilized to form leak-free fluidic couplings between two components. Ferrules may be employed in applications entailing small-scale fluid flows, such as analytical instruments and microfluidic devices, and thus may be sized to join a small-bore conduit such as a capillary tube or fitting with another component, or to create a sealed connection between two conduits with the use of a union or tee connection. The coupling may be established by a solid-to-solid seal that is secured by mating two surfaces together, one of which is an outer surface of the ferrule. The coupling may be formed under mechanical compression achieved by applying torque to a compression nut or equivalent component such that the nut bears against the ferrule. Depending on design, torque may be applied manually (i.e., hand-tightening or finger-tightening) or with the aid of a wrench or other tool. 
         [0004]    In a typical example of a conventional fluidic coupling utilizing a ferrule, a conduit is inserted through the bore of the ferrule and the conduit and ferrule are inserted into the interior of a union or other structure with which the ferrule is to form a sealed interface. The conduit also passes through a compression nut. The nut is threaded onto the union and rotated (screwed). Rotation axially translates the nut directly into the contact with the ferrule. Consequently, the ferrule is axially translated into contact with an inside surface of the union under a compressive force imparted by rotation of the nut, thereby creating a sealed interface between the ferrule and the inside surface against which the ferrule bears. The ferrule may also be shaped so that the compressive load also causes the ferrule to bear against the portion of the conduit residing in the ferrule&#39;s bore. 
         [0005]    This type and other types of conventional fluidic couplings have disadvantages. In a conventional fluidic coupling provides no mechanism for a user to feel and limit the torque or force develops during rotation of the nut, which may result in a wide variation of compressive loads applied by users from one coupling site to another. Moreover, depending on the system or environment in which the fluidic coupling operates, the fluidic coupling may be subjected to thermal cycling. The thermal cycling may be significant, ranging for example from −80° C. (cryogenic liquid N 2 ) to 400° C. Thermal cycling may cause thermal expansion and contraction of the solid components, and material relaxation due to annealing. Hence, thermal cycling may adversely affect the reliability of sealing interfaces. In particular, thermal cycling may reduce the sealing pressure at the solid-to-solid interfaces and thus cause undesirable fluid leakage, requiring the nut to be retightened to reestablish the sealing pressure or in some cases requiring one or more components of the coupling assembly to be replaced. The sealing pressure is proportional to the compressive load maintained on the solid-to-solid interface. Such an interface is very sensitive to the level of contact pressure being applied because there is very little elasticity in the system. Thus, a slight reduction in pressure due to thermal cycling or other causes may result in fluid leakage. 
         [0006]    In general, there is an ongoing need for improving fluidic couplings. There is also a need for providing a fluidic coupling that enables compression to be applied consistently, without needing to measure torque or compressive load. There is also a need for providing a fluidic coupling that maintains reliable sealing interfaces over many cycles of operation before requiring maintenance. There is also a need for providing a fluidic coupling that minimizes sensitivity to thermal cycling. 
       SUMMARY 
       [0007]    To address the foregoing problems, in whole or in part, and/or other problems that may have been observed by persons skilled in the art, the present disclosure provides methods, processes, systems, apparatus, instruments, and/or devices, as described by way of example in implementations set forth below. 
         [0008]    According to one embodiment, a fluidic coupling device, includes: a housing including a first housing end, a second housing end, and a housing bore extending along an axis from the first housing end to the second housing end; a ferrule including a tapered outer surface and insertable into the housing bore; a piston insertable into the housing bore such that the piston contacts the ferrule; a spring including an axial series of spring washers and insertable into the housing bore such that the piston is between the spring and the ferrule; and a cap insertable into the housing bore and into contact with the spring, the cap being threadedly engageable with the first housing end, wherein rotation of the cap or the housing compresses the spring and translates the piston against the ferrule such that the tapered outer surface and a tapered inner surface are compressed together, and wherein the tapered inner surface is selected from the group consisting of: a tapered inner surface of the piston; and a tapered inner surface of a body attachable to the second housing end. 
         [0009]    According to another embodiment, the fluidic coupling device includes a gripping component extending outward from the housing and configured for gripping by a user to facilitate manual rotation of the housing. 
         [0010]    According to another embodiment, the piston includes the tapered inner surface, and rotation of the cap or the housing translates the tapered inner surface into contact with the tapered outer surface. 
         [0011]    According to another embodiment, the body includes the tapered inner surface, and rotation of the cap or the housing translates the tapered outer surface into contact with the tapered inner surface. 
         [0012]    According to another embodiment, the fluidic coupling device includes a first conduit extending through respective bores of the first cap, the first spring, the first piston and the first ferrule, wherein compression of the first tapered outer surface and the first tapered inner surface together compresses the first ferrule against the first conduit; and a second conduit extending through respective bores of the second cap, the second spring, the second piston and the second ferrule, wherein compression of the second tapered outer surface and the second tapered inner surface together compresses the second ferrule against the second conduit, and the first conduit and the second conduit are in fluid communication along the axis. 
         [0013]    According to another embodiment, a fluidic coupling kit includes a fluidic coupling device. The components of the fluidic coupling device may include a housing, a piston, a spring and a cap. The components may all be disassembled, one or more components may be assembled together, or all components may be assembled together. In some embodiments, the fluidic coupling kit may include one or more ferrules. In some embodiments, the fluidic coupling kit may include one or more conduits. 
         [0014]    According to another embodiment, a fluidic assembly includes: a fluidic coupling device; a body including a body bore and threadedly engageable with the second housing end; and a conduit extending through respective bores of the cap, the spring, the piston, and the ferrule such that the conduit communicates with or extends into the body bore, wherein rotation of the housing relative to the body compresses the tapered outer surface and the tapered inner surface together to form a fluidic seal therebetween, and compresses the ferrule against the conduit. 
         [0015]    According to another embodiment, the body is part of an analytical instrument. 
         [0016]    According to another embodiment, the conduit and/or the body bore communicates with an ionization chamber. 
         [0017]    According to another embodiment, a fluidic coupling device includes: a housing including a first housing end, a second housing end, a housing bore extending along an axis from the first housing end to the second housing end, and a first passage oriented at an angle to the axis; a piston disposed in the housing bore; a spring including an axial series of spring washers disposed in the housing bore; a cap disposed in the housing bore wherein the spring is between the cap and the piston, the cap including a second passage and threadedly engaged with the first housing end to a locked position at which the first passage is aligned with the second passage; and a pin extending through the first passage and the second passage, wherein the pin retains the cap in the locked position. 
         [0018]    According to another embodiment, a fluidic coupling kit includes: one or more fluidic coupling devices; and a body including a first body end, a second body end, and a body bore extending along the axis from the first body end to the second body end, wherein the second housing end of each fluidic coupling device is threadedly engageable with a selected one of the first body end and the second body end. 
         [0019]    According to another embodiment, a method for making a fluidic coupling includes: inserting a ferrule into a fluidic coupling device, the fluidic coupling device including a housing, a piston, a spring including an axial series of spring washers, and a cap, wherein the piston is disposed in the housing between the spring and the ferrule, and the cap is threadedly engaged with a first housing end of the housing; inserting a conduit through respective bores of the cap, the spring, the piston and the ferrule; threadedly engaging a second housing end of the housing with a body such that the conduit extends into an interior of the body; and forming a fluidic seal between the ferrule and the piston and between the ferrule and the body by rotating the housing relative to the body, wherein rotating the housing compresses the spring between the cap and the piston, compresses the ferrule against the conduit, and compresses a tapered outer surface of the ferrule against a tapered inner surface, and wherein the tapered inner surface is selected from the group consisting of: a tapered inner surface of the piston; and a tapered inner surface of a body attachable to the second housing end. 
         [0020]    According to another embodiment, a method for assembling a fluidic coupling device includes: inserting a piston into a housing bore of a housing, wherein the housing bore extends along an axis; inserting a spring including an axial series of spring washers into the housing bore; threadedly engaging a cap with the housing such that the spring is between the cap and the piston; and rotating the cap relative to the housing to translate the cap axially toward the spring. 
         [0021]    According to another embodiment, the housing includes a first passage oriented at an angle to the axis, and the cap is rotated until a second passage of the cap is aligned with the first passage. The cap is retained in a locked position by inserting a pin through the first passage and the second passage. 
         [0022]    According to another embodiment, rotating the cap to the locked position compresses the spring between the cap and the piston. 
         [0023]    Other devices, apparatus, systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The invention can be better understood by referring to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views. 
           [0025]      FIG. 1  is a side view of an example of a ferrule. 
           [0026]      FIG. 2  is an exploded perspective view of an example of a fluidic coupling device according to one embodiment. 
           [0027]      FIG. 3  is an assembled perspective view of the fluidic coupling device illustrated in  FIG. 2 . 
           [0028]      FIG. 4  is a side view of an example of a fluidic assembly formed by fluidly coupling the fluidic coupling device illustrated in  FIGS. 2 and 3  to another component. 
           [0029]      FIG. 5  is a cross-sectional view of the fluidic assembly taken along line A-A in  FIG. 4 . 
           [0030]      FIG. 6  is a detailed view of a region in  FIG. 5  designated “B.” 
           [0031]      FIG. 7  is an exploded perspective view of an example of a fluidic coupling device according to another embodiment. 
           [0032]      FIG. 8  is an assembled perspective view of the fluidic coupling device illustrated in  FIG. 7 . 
           [0033]      FIG. 9  is a side view of an example of a fluidic assembly formed by fluidly coupling the fluidic coupling device illustrated in  FIGS. 7 and 8  to another component. 
           [0034]      FIG. 10  is a cross-sectional view of the fluidic assembly taken along line C-C in  FIG. 9 . 
           [0035]      FIG. 11  is a detailed view of a region in  FIG. 10  designated “D.” 
           [0036]      FIG. 12  is a side view of an example of a fluidic coupling device or assembly according to another embodiment. 
           [0037]      FIG. 13  is a cross-sectional view of the fluidic coupling assembly taken along line E-E in  FIG. 12 . 
           [0038]      FIG. 14  is a detailed view of a region in  FIG. 13  designated “F.” 
           [0039]      FIG. 15A  is a chromatogram acquired from initial testing of a fluidic coupling device having a known configuration that was newly installed in a GC-MS system. 
           [0040]      FIG. 15B  is a chromatogram acquired during the same testing referred to above in conjunction with  FIG. 15A , after subjecting the fluidic coupling device of known configuration to 25 thermal cycles. 
           [0041]      FIG. 16A  is a chromatogram acquired from of a fluidic coupling device having a configuration as presently disclosed herein. 
           [0042]      FIG. 16B  is a chromatogram acquired during the same testing referred to above in conjunction with  FIG. 16A , after over 300 sample injections. 
       
    
    
     DETAILED DESCRIPTION 
       [0043]    In the present context, the term “conduit” may encompass any type of tube through which a fluid may flow. In some embodiments, the conduit may have an inside or outside diameter on the millimeter- or micrometer-scale (e.g., capillary tubes, small-bore chromatographic columns, etc.). 
         [0044]    In the present context, the term “ferrule” may encompass any type of fluidic connector, i.e., a component designed to form a fluidic connection between two conduits. The resulting fluidic connection is typically fluid-tight within a specified range of intended operating pressures. The ferrule may be sized to form a joint with a conduit, or between two conduits, having diameters on the millimeter- or micrometer-scale, in which case the ferrule may be considered as being a microfluidic connector. In some small-scale examples, the ferrule has a length ranging from 1 to 10 mm, a maximum outer diameter ranging from 1 to 10 mm, and a bore size (inside diameter) ranging from 0.1 to 2 mm. As a further example, the ferrule may be sized to receive a gas chromatograph (GC) column. In typical applications, GC columns have internal diameters ranging from 50-530 μm. In some examples, the ferrule may have two bores running through its length. The ferrule may be configured for joining conduits, or joining a conduit with another hollow component, composed of dissimilar materials (e.g., fused silica glass and metal) and/or different diameters. As one non-limiting example, the ferrule may be utilized in conjunction with analytical instrumentation such as chromatography- or spectrometry-based systems. The ferrule may be designed to operate as a compression fitting. In this case, a conduit may be inserted into the ferrule&#39;s inner bore, two conduits may be inserted into the opposite ends of the ferrule&#39;s inner bore, and an appropriate technique is then implemented to compress or clamp the ferrule onto the conduits to form a fluidic seal, such as by employing a compression nut or a tool. The ferrule may also be configured as a three-way connector. 
         [0045]      FIG. 1  is a side view of an example of a ferrule  100 . The ferrule  100  typically includes a body of circular cross-section. The body includes an outer surface  104  and an axial ferrule bore  106  extending between two axially opposing ferrule end surfaces  108  and  110 . The outer surface  104  typically includes a tapered (e.g., conical) outer surface  112 . The tapered outer surface  112  enables the ferrule  100  to be compressed against the surface of another structure (not shown) with a force that has both axial and radial components relative to the axis, as shown by arrows. The surface against which the tapered outer surface  112  is compressed may or may not also be tapered. If the surface against which the tapered outer surface  112  is compressed is tapered, it may be tapered at a different angle than the tapered outer surface  112 . The ferrule  100  may be composed of a polymer or soft metal having a degree of deformability suitable for making a fluidic coupling by manual force (e.g., by hand-tightening a compression nut). Alternatively, the ferrule  100  may be composed of a hard metal in which case a tool such as a wrench may be employed in making a fluidic coupling (e.g., by swaging). 
         [0046]      FIG. 2  is an exploded perspective view of an example of a fluidic coupling device  200  according to one embodiment.  FIG. 3  is an assembled perspective view of the fluidic coupling device  200 . The fluidic coupling device  200  may include a housing  202 , a piston  204 , a spring  206 , and a cap  208 . The housing  202  may include a first housing end  212 , a second housing end  214 , and a housing bore  216  extending along a longitudinal axis of the fluidic coupling device  200  between the first housing end  212  and the second housing end  214 . The piston  204  may include a first piston end  218  and a second piston end  220 . The piston  204  may include a piston head  222  of larger outer diameter than the rest of the piston  204 . The cap  208  may include a threaded section  224  configured for engaging a threaded section (not shown) of the housing  202  at the first housing end  212 . In the illustrated example, the cap&#39;s threaded section  224  is an outer section configured for mating with internal threads of the housing bore  216 . Alternatively, the cap  208  may include internal threads configured for mating with external threads located at the outer surface of the first housing end  212 . The housing  202  may also include a threaded section (internal or external threads, not shown) at the second housing end  214 , which may be configured for engaging an external body (not shown) with which the fluid coupling device  200  is to interface. 
         [0047]    The spring  206  may include a plurality of spring washers  226  arranged (stacked) in an axial series along the longitudinal axis. The spring washers  226  may be configured as Belleville washers, which may also be known as Belleville springs, cupped spring washers, conical spring washers, disc springs, or coned-disc springs. As appreciated by persons skilled in the art, a spring washer  226  of this type, or a portion of this spring washer  226 , has a conical shape such that the spring washer  226  imparts an axial force when deformed. Any number of individual spring washers  226  may be provided as needed for attaining a desired overall spring constant or amount of deflection of the resulting spring  206 . Moreover, the respective orientations of the individual spring washers  226  may be varied as needed for modifying the spring constant or deflection. That is, all of the spring washers  226  may be oriented in the same way, or the orientations of one or more of the spring washers  226  may alternate (i.e., the conical portions of two adjacent spring washers  226  may face each other). 
         [0048]    To assemble the fluidic coupling device  200 , the piston  204  is inserted into the housing bore  216 , such as through the first housing end  212 . In some embodiments, the travel of the piston  204  is limited by a protrusion or stop member (not shown) in the housing bore  216  against which the piston head  222  comes into contact. The protrusion may be, for example, an annular shoulder or one or more tabs. The spring  206  is then inserted into the housing bore  216  and into contact with the first piston end  218 , i.e., the first spring washer in the series contacts the first piston end  218 . The cap  208  is then inserted into the housing bore  216  by threadedly engaging the cap  208  with the housing  202 . That is, rotation of the cap  208  axially translates the cap  208  in the housing bore  216  in the direction of the spring  206  and piston  204 . With the cap  208  installed, the spring  206  is disposed between the cap  208  and the piston  204 . The cap  208  may be rotated until coming into contact with the spring  206 , i.e., the last spring washer in the series. In some embodiments, during assembly the cap  208  is rotated enough to compress (pre-compress) the spring  206  to some degree, which may be facilitated in embodiments in which the piston head  222  abuts a protrusion in the housing bore  216 . After assembly, the fluidic coupling device  200  is ready for use in making a fluidic coupling with another component, examples of which are described below. 
         [0049]    The piston  204 , spring  206 , and cap  208  may have respective bores aligned with each other in the housing  202  along the axis. These bores may be sized to receive a conduit, as described below. 
         [0050]    In some embodiments, the fluidic coupling device  200  includes one or more pins  228 , the housing  202  includes a like number of first pin passages  230 , and the cap  208  includes one or more corresponding second pin passages (not shown). The first pin passages  230  and second pin passages may extend through the respective structures of the housing  202  and cap  208  at an angle (e.g., ninety degrees) to the longitudinal axis. In this embodiment, the cap  208  is rotatable (axially translatable) to a locked position. At the locked position, the first pin passage(s)  230  are aligned with the second pin passage(s), enabling the pin(s)  228  to be inserted into the first pin passage(s)  230  and second pin passage(s). The pin(s)  228  may be secured in any manner, such as by press-fitting, threading, etc. The locked position with the pin(s)  228  inserted fixes the axial position of the cap  208 , preventing any further rotation thereof. The fluidic coupling device  200  may, for example, be configured such that the spring  206  is compressed (pre-compressed) to a desired degree at the locked position. Alternatively or additionally, the locked position may be utilized to fix the components of the fluidic coupling device  200  in an assembled state to facilitate shipping the fluidic coupling device  200  to user or initial handling of the fluidic coupling device  200  by the user in preparation for use. 
         [0051]    In some embodiments, the housing  202  includes one or more lateral apertures  232  extending through the housing structure from the outside to the housing bore  216 . The lateral aperture(s)  232  may be located adjacent to the installed spring  206 . During use of the fluidic coupling device  200 , the lateral aperture(s)  232  may facilitate convective heat transfer from the spring  206  and nearby structures to reduce the adverse effect of thermal cycling on the integrity of the fluidic seal(s) provided by the fluidic coupling device  200 . The configuration of the spring  206  may also enhance heat removal from the fluidic coupling device  200 , in that the multiple spring washers  226  may provide a large surface area for heat removal in a manner analogous to cooling fins. 
         [0052]    In some embodiments, the housing  202  includes one or more gripping components  234  extending outwardly from the main structure of the housing  202 . The gripping components  234  are configured to be manipulated by a user to facilitate rotation of the housing  202  relative to a component with which the housing  202  is threadedly engaged, during the process of making a fluidic coupling as described by example below. In the illustrated embodiment, the gripping components  234  are handles or wings. In another embodiment, the gripping component  234  may be an annular component (e.g., a knob, wheel, collar, etc.) affixed to the housing  202 . The outer surface of the annular component may be configured to facilitate gripping by the user; for example, the outer surface may be knurled. 
         [0053]      FIG. 4  is a side view of an example of a fluidic assembly or system  400  formed by fluidly coupling the fluidic coupling device  200  to another component  402 . The component  402  may be or include a hollow body  404 . A conduit  406  passes through the fluidic coupling device  200 . Depending on the type of component  402  or fluid handling application being implemented, the conduit  406  may extend completely through the body  404  as illustrated, or may instead extend through a portion of the body  404  in open communication with the body&#39;s interior. As described by example below, a fluidic coupling or joint is made by creating sealed interfaces among the fluidic coupling device  200 , the body  404 , the conduit  406 , and a ferrule  100  (e.g.,  FIG. 1 ). 
         [0054]    In some embodiments, the body  404  is, is part of, or communicates with a chamber that is sealable in a fluid-tight manner. The chamber may require operation at a controlled pressure, which may be atmospheric pressure, above atmospheric pressure, or sub-atmospheric pressure (including, for example, very low pressure or vacuum). In such cases, the pressure in the chamber may be significantly different from the ambient pressure outside the chamber and/or the pressure inside the fluidic coupling device  200 . As described below, the fluidic coupling device  200  is interfaced with the body  404  in a manner that provides one or more fluid-tight seals. The resulting sealing interface prevents fluid leakage (or pressure leakage) between the interiors of the fluidic coupling device  200  and the body  404 , and leakage out from or into the fluidic coupling device  200  and the body  404 . In some embodiments, the body  404  is part of an analytical instrument. As one non-limiting example, the body  404  may be associated with the inlet section of a mass spectrometer (MS). Continuing with this example, the body  404  may be part of or communicate with the ionization chamber (or “ion source”) of an MS, and the conduit  406  may be the column of a gas chromatograph (GC) or may be a separate conduit that receives the output flow from an upstream GC column. The GC and its column may operate around atmospheric pressure and, depending on type, the ionization chamber may operate around atmospheric pressure or at a vacuum level. In either case, fluid leakage out from the ionization chamber or between the GC and the ionization chamber is undesirable. 
         [0055]      FIG. 5  is a cross-sectional view of the fluidic assembly  400  taken along line A-A in  FIG. 4 .  FIG. 6  is a detailed view of a region in  FIG. 5  designated “B.” In this embodiment, the piston  204  includes a tapered (e.g., conical) inner surface  502  at the second piston end, which defines a portion of the piston bore. The tapered inner surface  502  is characterized by the diameter of the piston bore increasing in the direction toward the second piston end. The body  404  has a body bore  504  and a threaded section  506 . In the illustrated embodiment, the threaded section  506  of the body  404  includes outer threads, and the second housing end includes inner threads configured to mate with the body&#39;s outer threads. Alternatively, the body  404  may include inner threads configured to mate with outer threads of the second housing end. 
         [0056]      FIG. 5  also shows the cap  208  initially provided in the above-described locked position, at which the pin  228  is inserted through the first pin passage  230  of the housing  202  and a corresponding second pin passage  508  of the cap  208 .  FIG. 5  also shows a protrusion or stop member  510  in the housing bore. The head of the piston  204  may comes into contact with the protrusion  510  to limit the extent of the piston&#39;s travel. 
         [0057]    To make the fluidic coupling, a ferrule  100  is inserted into the housing bore from the second housing end, such that the ferrule&#39;s tapered outer surface  112  faces the piston&#39;s tapered inner surface  502 . The conduit  406  is then inserted through the housing  202  from either the first housing end or second housing end. For example, the conduit  406  may be inserted through the cap bore, the spring bore (the successive bores of the spring washers), the piston bore, and the ferrule bore. The conduit  406  is then inserted into the body bore  504 . The second housing end is then threadedly engaged with the body  404  and the housing  202  is rotated relative to the body  404 , such as by manipulating one or more gripper elements  234  ( FIG. 4 ) of the housing  202 . Rotation of the housing  202  axially translates the piston  204  against the ferrule  100 . In the illustrated embodiment, rotation of the housing  202  axially translates the tapered inner surface  502  against the tapered outer surface  112 . In turn, rotation of the housing  202  axially translates the ferrule end surface opposite to the tapered outer surface  112  against a body surface  512  of the body  404 , which for alignment purposes may be part of a seat sized to receive the ferrule  100 . Rotation of the housing  202  compresses the spring  206 , which imparts an axial compression force as depicted by arrows  602  in  FIG. 6 . Rotation of the housing  202  also causes the tapered inner surface  502  and the tapered outer surface  112  to be compressed together to form a fluidic seal therebetween, and the ferrule end surface and the body surface  512  to be compressed together to form a fluidic seal therebetween. The fluidic seals are depicted by regions or contact points  604  in  FIG. 6 . This compression in turn causes the ferrule  100  to bear down on the conduit  406 . 
         [0058]    The fluidic coupling device  200  (e.g., the piston  204  and spring  206 ) may be configured such that the maximum extent of rotation of the housing  202  required to form adequate fluidic seals may be determined by “feel.” That is, rotation of the housing  202  causes deformation of the spring washers  226 , and this deformation will eventually cease (e.g., all spring washers  226  will eventually flatten out to the same degree). The cessation in the deformation is tactile and discernible by the user, and thus may indicate to the user that adequate fluidic seals have been achieved such that further rotation is not needed. In this way, the fluidic coupling device  200  is configured to minimize variation in the compressive load applied when coupling the fluidic coupling device  200  to a component such as the body  404 . That is, multiple fluidic coupling devices  200  may be utilized to make respective connections with different components, with the expectation that largely the same compressive load or torque will be applied by the user. Different users may learn or be instructed to use the same maximum feel to consistently apply the same load to a coupling site, without needing the aid of a torque measuring instrument or other instrument. The fluidic coupling device  200  may thus enable the fluidic sealing process to be less user dependent as compared to known devices. 
         [0059]    An example of a fluidic coupling device consistent with the fluidic coupling device  200  described above and illustrated in  FIGS. 2-6  has been subjected to thermal cycling tests using a plastic (graphite/Vespel® polymer) ferrule. The tests indicated that the fluidic coupling device  200  maintains a reliable fluidic seal over several cycles (e.g., thirty or more) before requiring retightening. It has been shown that the spring  206  continues to apply good and reliable sealing pressure to the ferrule regardless of thermal expansion or contraction or material relaxation. The floating piston  204  with the compact loaded spring system on one side reduces the sensitivity of the sealing pressures attained in the fluidic coupling device  200  to temperature changes and material changes caused by temperature changes. 
         [0060]    The hand-tightening of the fluidic coupling device  200 , i.e., manual rotation of the housing  202 , which may be aided by using the optional gripping element  234 , is generally a viable method when employing a ferrule composed of a polymer or a sufficiently deformable soft metal. In addition to rotating the housing  202 , the cap  208  may be rotated relative to the housing  202  to apply compressive force. If the cap  208  is initially in a locked position as described above, the pin(s)  228  may need to be removed to enable further rotation of the cap  208 . The fluidic coupling device  200  is also compatible for use with hard metal ferrules, in which case rotation of the cap  208  with the use of a tool may be required. The cap  208  may, for example, include flats (e.g., like a hex bolt) for gripping by a wrench. 
         [0061]      FIG. 7  is an exploded perspective view of an example of a fluidic coupling device  700  according to another embodiment.  FIG. 8  is an assembled perspective view of the fluidic coupling device  700 . The fluidic coupling device  700  may include a housing  702 , a piston  704 , a spring  706 , and a cap  708 . The housing  702  may include a first housing end  712 , a second housing end  714 , and a housing bore  716  extending along a longitudinal axis of the fluidic coupling device  700  between the first housing end  712  and the second housing end  714 . The piston  704  may include a first piston end  718  and a second piston end  720 . The piston  704  may include a piston head  722  of larger outer diameter than the rest of the piston  704 . The spring  706  may include a plurality of spring washers  726  as described above. The cap  708  may include a threaded section  724  configured for engaging a threaded section of the housing  702  at the first housing end  712 . In the illustrated example, the cap&#39;s threaded section  724  is an outer section configured for mating with internal threads (not shown) of the housing bore  716 . The housing  702  may also include a threaded section  725  (external threads in the present example) at the second housing end  714 , which may be configured for engaging an external body (not shown) with which the fluid coupling device  700  is to interface. 
         [0062]    The fluidic coupling device  700  may be assembled in the same or similar manner as the fluidic coupling device  200  described earlier in this disclosure and illustrated in  FIGS. 2-6 . In some embodiments, the fluidic coupling device  700  includes one or more pins  728 , the housing  702  includes a like number of first pin passages  730 , and the cap  708  includes one or more corresponding second pin passages (not shown). These components may cooperate to provide a locked position as described above. In some embodiments, the housing  702  includes one or more lateral apertures  732  as described above. In some embodiments, the housing  702  includes one or more gripping components  734  as described above. 
         [0063]      FIG. 9  is a side view of an example of a fluidic assembly  900  formed by fluidly coupling the fluidic coupling device  700  to another component  902 . The component  902  is or includes a hollow body  904 . A conduit  406  passes through the fluidic coupling device  700 . The conduit  406  may pass through the body  904  as illustrated, or may instead extend through a portion of the body  904  in open communication with the body&#39;s interior. The body  904  may be associated with a chamber, analytical instrument, etc., as described above. 
         [0064]      FIG. 10  is a cross-sectional view of the fluidic assembly  900  taken along line C-C in  FIG. 9 .  FIG. 11  is a detailed view of a region in  FIG. 10  designated “D.” In this embodiment, the piston  704  includes a piston end surface  1002  at the second piston end, which is typically a flat surface. The body  904  has a body bore  1004  and a threaded section  1006 . In the illustrated embodiment, the threaded section  1006  of the body  904  includes inner threads, and the outer threads of the threaded section  725  at the second housing end are configured to mate with the body&#39;s inner threads. Also in this embodiment, the body  904  includes a tapered inner surface  1008  that defines a portion of the body bore  1004 . Thus, in this embodiment the orientation of the ferrule  100  is reversed as compared to the embodiment illustrated in  FIGS. 2-6 , with the tapered outer surface  112  facing the tapered inner surface  1008  of the body  904  and the opposing (typically flat) ferrule end surface facing the piston end surface  1002 . 
         [0065]    To make the fluidic coupling, the ferrule  100  is inserted into the housing bore from the second housing end in the orientation just noted. The coupling process may be implemented in the same or similar manner as that described above in conjunction with the embodiment of  FIGS. 2-6 . Rotation of the housing  702  compresses the spring  706 . Rotation of the housing  702  also axially translates the piston  704  against the ferrule  100 , which in turn translates the tapered outer surface  112  against the tapered inner surface  1008  of the body  904 . Rotation of the housing  702  causes the tapered inner surface  1008  and the tapered outer surface  112  to be compressed together to form a fluidic seal therebetween, and the ferrule end surface and the piston end surface  1002  to be compressed together to form a fluidic seal therebetween. This compression in turn causes the ferrule  100  to bear down on the conduit  406 . The cap  708  may also be rotated relative to the housing  702  to contribute to creation of the fluidic seals, as described above. The fluidic coupling device  700  is configured to provide a consistent, repeatable compressive load in a manner analogous to that described above in conjunction with  FIGS. 2-6 . 
         [0066]      FIG. 12  is a side view of an example of a fluidic coupling device or assembly  1200  according to another embodiment.  FIG. 13  is a cross-sectional view of the fluidic coupling assembly  1200  taken along line E-E in  FIG. 12 .  FIG. 14  is a detailed view of a region in  FIG. 13  designated “F.” In this embodiment, the fluidic coupling assembly  1200  is configured for creating a fluid-tight joint between a first conduit  1252  and a second conduit  1254 . 
         [0067]    The fluidic coupling assembly  1200  includes a first fluidic coupling device  1256 , a second fluidic coupling device  1258 , and a body  1260 . Each fluidic coupling device  1256  and  1258  may be configured and assembled in the same or similar manner as the fluidic coupling device  200  illustrated in  FIGS. 2-6  or the fluidic coupling device  700  illustrated in  FIGS. 7-11 . By way of example, the fluidic coupling devices  1256  and  1258  illustrated in  FIGS. 12-14  are configured similarly to the fluidic coupling device  700  illustrated in  FIGS. 7-11 . 
         [0068]    Thus, in the illustrated embodiment the first fluidic coupling device  1256  may include a first housing  702 , a first piston  704 , a first spring  706 , and a first cap  708 . The first housing  702  may include a first housing end, a second housing end, and a first housing bore extending along a longitudinal axis of the fluidic coupling device  700  between the first housing end and the second housing end. The first piston  704  may include a first piston end and a second piston end. The first piston  704  may include a piston head of larger outer diameter than the rest of the first piston  704 . The first spring  706  may include a plurality of spring washers as described above. The first cap  708  may include a threaded section configured for engaging a threaded section of the first housing  702  at the first housing end. Also in the illustrated embodiment, the second fluidic coupling device  1258  may include a second housing  1272 , a second piston  1274 , a second spring  1276 , and a second cap  1278 . The second housing  1272  may include a third housing end, a fourth housing end, and a second housing bore extending along the axis between the third housing end and the fourth housing end. The second piston  1274  may include a third piston end and a fourth piston end. The second piston  1274  may include a piston head of larger outer diameter than the rest of the second piston  1274 . The second spring  1276  may include a plurality of spring washers as described above. The second cap  1278  may include a threaded section configured for engaging a threaded section of the second housing  1272  at the third housing end. 
         [0069]    In this embodiment, the body  1260  serves as a union or joint. The body  1260  includes a first body end  1262 , a second body end  1264 , and a body bore  1302  extending along the axis of the fluid coupling assembly  1200 . The body  1260  includes threaded sections  1304  and  1306  at the first body end  1262  and second body end  1264  configured for engaging threaded sections  1225  and  1245  of the first fluidic coupling device  1256  and second fluidic coupling device  1258 , respectively. The body  1260  further includes a first tapered inner surface  1308  and a second tapered inner surface  1310  defining portions of the body bore  1302 . The first tapered inner surface  1308  faces the first body end  1262 , and the second tapered inner surface  1310  faces the second body end  1264 . The body bore  1302  may include a central region  1312  of constant diameter between the first tapered inner surface  1308  and second tapered inner surface  1310 . 
         [0070]    To make the fluidic coupling, a first ferrule  100  is inserted into the body  1260  from the first body end  1262  such that the tapered outer surface  112  of the first ferrule  100  faces the first tapered inner surface  1308  of the body  1260 . The first conduit  1252  is then inserted through the first fluidic coupling device  1256  and the first ferrule  100 . The first conduit  1252  may be inserted far enough that it extends into the central region  1312  of the body bore  1302 . The first fluidic coupling device  1256  is then threadedly engaged with the first body end  1262 . The housing  702  of the first fluidic coupling device  1256  is then rotated to create fluid seals in the same or similar manner as that described above in conjunction with the embodiment of  FIGS. 7-11 . A second ferrule  120  is then inserted into the body  1260  from the second body end  1264  such that a tapered outer surface  132  of the second ferrule  120  faces the second tapered inner surface  1310  of the body  1260 . The second conduit  1254  is then inserted through the second fluidic coupling device  1258  and the second ferrule  120 . The second conduit  1254  may be inserted far enough that it extends into the central region  1312  of the body bore  1302 . A gap in the central region  1312  between the first conduit  1252  and the second conduit  1254  may or may not remain after the coupling process is completed. The second fluidic coupling device  1258  is then threadedly engaged with the second body end  1264 . The housing  1272  of the second fluidic coupling device  1258  is then rotated to create fluid seals in the same or similar manner as described above. 
         [0071]    The order of one or more of the above-described steps may be varied. For example, both conduits  1252  and  1254  and ferrules  100  and  120  may be inserted into the body  1260  before operating either of the fluidic coupling devices  1256  and  1258  to apply compression. 
         [0072]    In other embodiments, the fluidic coupling devices  1256  and  1258  illustrated in  FIGS. 12-14  may be configured similarly to the fluidic coupling device  200  illustrated in  FIGS. 2-6 . In this case, the pistons  704  and  1274  may include the first and second tapered inner surfaces, respectively. The body  1260  may include (typically flat) end surfaces (in the place of the first and second tapered inner surfaces shown in  FIGS. 13 and 14 ) respectively facing the ferrules&#39; end surfaces that oppose the ferrules&#39; tapered outer surfaces  112  and  132 . The two ferrules  100  and  120  would thus be oriented in a reverse manner as compared to that shown in  FIGS. 13 and 14 . 
         [0073]    According to other embodiments, a fluidic coupling kit may be provided. In some embodiments, the fluidic coupling kit may include the fluidic coupling device  200 . In one embodiment, the fluidic coupling device  200  may be disassembled such as shown in  FIG. 2 . In another embodiment, the fluidic coupling device  200  may be assembled such as shown in  FIG. 3 . In the assembled fluidic coupling device  200 , the spring  206  may or may not be pre-compressed, and the cap  208  may or may not be in a locked position. In other embodiments, one or more ferrules  100  and/or conduits  406  suitable for use with the fluidic coupling device  200  may additionally be included in the fluidic coupling kit. In various embodiments, the fluidic coupling kit may include a container in which the components are disposed. The container may be utilized for shipping the fluidic coupling kit to a user or storage of the fluidic coupling kit by the user. In various embodiments, the fluidic coupling kit may include instructions for use of the fluidic coupling device  200 . 
         [0074]    In other embodiments, the fluidic coupling kit may include the fluidic coupling device  700 . The fluidic coupling device  700  may be disassembled such as shown in  FIG. 7  or assembled such as shown in  FIG. 8 . In other embodiments, one or more ferrules  100  and/or conduits  406  may additionally be included. In various embodiments, the fluidic coupling kit may include a container, and may further include instructions for use. 
         [0075]    In other embodiments, the fluidic coupling kit may include the fluidic coupling assembly  1200 , with one or more fluidic coupling devices  1256  and  1258  and bodies  1260 . The fluidic coupling devices  1256  and  1258  may initially be provided in assembled or disassembled form. The fluidic coupling devices  1256  and  1258  may initially be threadedly engaged with the body  1260 . In use, the user may disengage the fluidic coupling devices  1256  and  1258  from the body  1260 , insert ferrules, and then reattach the fluidic coupling devices  1256  and  1258 . In other embodiments, one or more ferrules  100  and  120  and/or conduits  1252  and  1254  may additionally be included. In various embodiments, the fluidic coupling kit may include a container, and may further include instructions for use. 
         [0076]    In other embodiments, the fluidic coupling kit may include a combination of one or more of the fluidic coupling devices, bodies, ferrules, conduits, etc. described above. 
       EXAMPLE 
       [0077]    An example of a fluidic coupling device as presently disclosed herein (presently disclosed device) was tested and compared to an existing fluidic coupling device of a known configuration (known device). The presently disclosed device had a configuration consistent with that described above and illustrated in  FIGS. 2-6 , with the floating piston and spring system, and the ability to form fluidic connections by finger-tightening. The known device had a configuration that did not include a spring-loaded piston and requires wrench-tightening to form fluidic connections. Both the presently disclosed device and the known device utilized the same model of graphite/Vespel® polymer ferrules of known design commercially available from Agilent Technologies Inc., Santa Clara, Calif., USA. In both cases, the ferrules utilized were fresh, i.e., had not been previously used to form fluidic connections. The presently disclosed device was utilized to form new fluidic connections at the transfer line and GC inlet of a 5975C GC/MSD system commercially available from Agilent Technologies, Inc., Santa Clara, Calif., USA. Several experimental runs were performed on a specific sample material and chromatographic data was acquired. For comparison, the known device was utilized to form new fluidic connections at the transfer line and GC inlet of the same 5975C GC/MSD system, and several experimental runs were performed on the same sample material and chromatographic data was acquired. 
         [0078]      FIGS. 15 and 16  provide examples of the chromatographic data (signal intensity over time) acquired during testing. Specifically,  FIG. 15A  is a chromatogram acquired from the first run utilizing the known device and known ferrule. By comparison,  FIG. 15B  is a chromatogram acquired after  25  sample injections that incorporated an equal number of thermal cycles with no changes to the chromatographic system. As clearly shown by arrows, a significant background contribution to the signal was detected, and was the result of air leaking from the fluidic connections formed from the known device and ferrule. 
         [0079]      FIG. 16A  is a chromatogram acquired from the first run utilizing the presently disclosed device and known ferrule. By comparison,  FIG. 16B  is a chromatogram acquired after over  300  sample injections that incorporated an equal number of thermal cycles. No change in the background signal is observed. No re-tightening of the device was done between these runs. The data demonstrates that the presently disclosed device maintains reliable sealing performance over many cycles of use, without requiring the use of a tool to form the fitting and without requiring retightening between operations. 
         [0080]    It will be understood that terms such as “communicate” and “in . . . communication with” (for example, a first component “communicates with” or “is in communication with” a second component) are used herein to indicate a structural, functional, mechanical, electrical, signal, optical, magnetic, electromagnetic, ionic or fluidic relationship between two or more components or elements. As such, the fact that one component is said to communicate with a second component is not intended to exclude the possibility that additional components may be present between, and/or operatively associated or engaged with, the first and second components. 
         [0081]    It will be understood that various aspects or details of the invention may be changed without departing from the scope of the invention. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation—the invention being defined by the claims.