Patent Description:
The invention relates generally to chromatography. More particularly, the invention relates to fittings for fluidic coupling for use in chromatography systems.

Chromatography is a set of techniques for separating a mixture into its constituents. Well-established separation technologies include HPLC (High Performance Liquid Chromatography), UPLC (Ultra Performance Liquid Chromatography) and SFC (Supercritical Fluid Chromatography). HPLC systems use high pressure, ranging traditionally between <NUM>,<NUM> psi (pounds per square inch), <NUM> MPa, to approximately <NUM>,<NUM> psi, <NUM> MPa, to generate the flow required for liquid chromatography (LC) in packed columns. Compared to HPLC, UPLC systems use columns with smaller particulate matter and higher pressures approaching <NUM>,<NUM> psi <NUM> GPa, to deliver the mobile phase. SFC systems use highly compressible mobile phases, which typically employ carbon dioxide (CO<NUM>) as a principle component.

In a typical LC system, a solvent delivery system takes in and delivers a mixture of liquid solvents to an injection system where an injected sample awaits the arrival of this mobile phase. The mobile phase carries the sample through a separating column. In the column, the mixture of the sample and mobile phase divides into bands depending upon the interaction of the mixture with the stationary phase in the column. A detector identifies and quantifies these bands as they exit the column.

Typical fluidic tube fittings for fluidic coupling in LC systems require an open-ended wrench for installation. This can cause issues during installation. If a wrench is unavailable, a user will not be able to apply enough torque for the fitting to properly tighten. Even if a wrench is available, using a tool such as a wrench for installation of a fitting can be difficult for some users and result in over-tightened or under-tightened installations.

Still further, typical tube fittings for fluidic coupling in LC systems often create debris from galling between a compression screw and a gasket and/or ferrule. Galling and debris reduces the life of the fitting. Other issues encountered in fittings are that many fittings allow for dead volume to exist between the fitting and a female receiver of a fluidic coupling. This dead space allows for liquid to accumulate without being moved through the fitting and hinders the accuracy of the system. Existing fitting systems also include many loose parts, which can create problems for users if parts are lost or dropped.

Thus, an improved fitting for fluidic coupling in an LC system would be well received in the art.

A prior art arrangement is known from <CIT> which relates to a plug for connecting capillaries.

In one exemplary embodiment, a fitting for fluidic coupling in a chromatography system includes a compression screw including an axial bore, a threaded portion, and a drive end; a tube assembly including a tube sleeve and an inner tube disposed through the sleeve, the tube sleeve and the inner tube each extending to an endface of the tube assembly, the tube sleeve including an outer surface; a seal body extending between a first endface and a second endface, the first endface abutting the endface of the tube assembly, the seal body including an outer surface; and a collar secured to the outer surface of the tube sleeve and the outer surface of the seal body.

Additionally, the tube sleeve and the inner tube are welded together at the endface.

Additionally or alternatively, the endface is a polished surface.

Additionally or alternatively, seal body is made of at least one of a high temperature polyimide and polyether ether ketone.

Additionally or alternatively, the collar includes a thin wall portion extending from a first end, and a thick wall portion extending from the thin wall portion to a second end, wherein a circumferential interior ridge is defined by a difference in thickness between the thin wall portion and the thick wall portion, wherein the circumferential interior ridge defines a surface that contacts the endface of the tube assembly.

Additionally or alternatively, the tube sleeve includes a reduced outer diameter portion extending from the endface, wherein the thin wall portion of the collar extends over the reduced outer diameter portion of the tube sleeve.

Additionally or alternatively, the thin wall portion of the collar is press fit over the reduced outer diameter portion of the tube sleeve, and wherein the thick wall portion of the collar is press fit over the seal body.

Additionally or alternatively, the compression screw includes a knurled grip portion located at a grip end opposite the drive end, the knurled grip portion configured to facilitate hand tightening of the compression screw into a receiver fitting.

Additionally or alternatively, the compression screw is made of a gall resistant stainless steel material.

Additionally or alternatively, the seal body includes an inner bore having dimensions that are equal or larger than an inner diameter of the inner tube.

Additionally or alternatively, the seal body is configured to deform over the second end when compressed against a surface of a receiver fitting.

Additionally or alternatively, the fitting includes a ring welded to the tube assembly configured to be pushed by the compression screw during tightening.

In another exemplary embodiment, a method of manufacturing a fitting for fluidic coupling in a chromatography system comprises: welding a tube sleeve and an inner tube at an endface of each of the tube sleeve and the inner tube to create a tube assembly having a welded tube assembly endface; and polishing the welded tube assembly endface.

Additionally or alternatively, the method includes abutting a surface of a seal body to the welded tube assembly endface; and securing a collar to an outer surface of the tube sleeve and an outer surface of the seal body.

Additionally or alternatively, the securing the collar further includes press fitting the collar to each of the outer surface of the tube sleeve and the outer surface of the seal body.

Additionally or alternatively, the method includes maintaining a fluid tight seal between the surface of the seal body and the welded tube assembly endface such that fluid conveyed through the inner tube and an axial opening of the seal body does not leak between the tube sleeve, the inner tube, and the collar.

In another exemplary embodiment, a method of fluidic coupling in a chromatography system comprises: providing a fitting including: a compression screw including an axial bore, a threaded portion, and a drive end; a tube assembly including a tube sleeve and an inner tube disposed through the sleeve, the tube sleeve and the inner tube each extending to an endface of the tube assembly, the tube sleeve including an outer surface; a seal body extending between a first endface and a second endface, the first endface abutting the endface of the tube assembly, the seal body including an outer surface; and a collar secured to the outer surface of the tube sleeve and the outer surface of the seal body; and fluidically coupling the fitting to a receiver fitting of a liquid chromatography system by hand tightening the compression screw without a tightening tool.

Additionally or alternatively, the method includes maintaining a fluid tight seal between the first endface of the seal body and the endface of the tube assembly; conveying fluid through the inner tube and an axial opening of the seal body; and avoiding any leaking of the fluid between the tube sleeve, the inner tube, and the collar.

Additionally or alternatively, the method includes deforming the seal body over an end of the collar when compressed against a surface of a receiver fitting.

In another exemplary embodiment, a fluidic coupling in a chromatography system comprises: a fitting for fluidic coupling comprising: a compression screw including an axial bore, a threaded portion, and a drive end; a tube assembly including a tube sleeve and an inner tube disposed through the sleeve, the tube sleeve and the inner tube each extending to an endface of the tube assembly, the tube sleeve including an outer surface; a seal body extending between a first endface and a second endface, the first endface abutting the endface of the tube assembly, the seal body including an outer surface; and a collar secured to the outer surface of the tube sleeve and the outer surface of the seal body; and a receiver fitting having a threaded bore and an inner bore having a sealing surface at an end opposite the threaded bore, the receiver fitting having a channel extending from the sealing surface to pass a fluid.

Additionally or alternatively, the threaded portion of the compression screw is engaged with the threaded bore of the receiver fitting pushing the second endface of the seal body against the sealing surface of the receiver fitting.

Additionally or alternatively, the seal body creates a fluid tight seal between the outer surface of the seal body and the tube assembly endface such that fluid conveyed through the inner tube and an axial opening of the seal body does not leak between the tube sleeve, the inner tube, and the collar.

In an exemplary arrangement, disclosed herein, not independently claimed, a fitting for fluidic coupling in a chromatography system comprises: a compression screw including an axial bore, a threaded portion, and a drive end; a tube having body and a greater diameter portion configured to be moved axially with the compressions screw, the tube including a counterbore extending from a front end to a seating surface; and a seal body extending between a first endface and a second endface, the first endface abutting the seating surface of the counterbore, the seal body including an outer surface dimensioned to fit within the counterbore.

Additionally or alternatively, the compression screw includes a back end opposite the drive end and at least one counterbore extending from the back end.

Additionally or alternatively, the at least one counterbore comprises a first counterbore extending to a first seating surface, and a second counterbore extending from the first seating surface to a second seating surface, wherein the greater diameter portion is a ring welded to a body of the tube, the ring dimensioned to fit into the second counterbore.

Additionally or alternatively, the fitting includes a retainer cap attached to the back end of the compression screw, the retainer cap dimensioned to be attached within the first counterbore with a press fit between the retainer cap and the first counterbore, the retainer cap configured to contact the ring to drive the tube forward with the compression screw during compression by the compression screw.

Additionally or alternatively, the retainer cap and the compression screw are configured to rotate about the tube and the ring during tightening of the compression screw in a receiver fitting.

Additionally or alternatively, the seal body is made of at least one of a high temperature polyimide and polyether ether ketone.

Additionally or alternatively, the counterbore includes a narrow wall portion axially extending from the seating surface toward the front end, the narrow wall portion configured to receive the first endface of the seal body in a press fit.

Additionally or alternatively, the seal body extends between the first endface and the second endface a length that is greater than an axial length of the at least one counterbore.

Additionally or alternatively, the seal body is configured to deform over the front end of the tube body when compressed against a surface of a receiver fitting.

Additionally or alternatively, the seal body includes an inner bore having dimensions that are equal or larger than an inner diameter of the tube body.

Additionally or alternatively, the compression screw includes a knurled grip portion located at a back end opposite the drive end, the knurled grip portion configured to facilitate hand tightening of the compression screw into a receiver fitting.

In another exemplary arrangement, disclosed herein, not independently claimed, a method of fluidic coupling in a chromatography system comprises: providing a fitting including: a compression screw including an axial bore, a threaded portion, and a drive end; a tube having body and a greater diameter portion configured to be moved axially with the compressions screw, the tube including a counterbore extending from a front end to a seating surface; a seal body extending between a first endface and a second endface, the first endface abutting the seating surface of the counterbore, the seal body including an outer surface dimensioned to fit within the counterbore; and fluidically coupling the fitting to a receiver fitting of a liquid chromatography system by hand tightening the compression screw without a tightening tool.

Additionally or alternatively, the method includes maintaining a fluid tight seal between the first endface of the seal body and the seating surface of the tube assembly; and conveying fluid through the tube and an axial opening of the seal.

Additionally or alternatively, the method includes deforming the seal body over the front end of the tube when compressed against a surface of a receiver fitting.

In another exemplary embodiment, a fluidic coupling in a chromatography system comprises: a fitting for fluidic coupling in a chromatography system comprising: a compression screw including an axial bore, a threaded portion, and a drive end; a tube having body and a greater diameter portion configured to be moved axially with the compressions screw, the tube including a counterbore extending from a front end to a seating surface; and a seal body extending between a first endface and a second endface, the first endface abutting the seating surface of the counterbore, the seal body including an outer surface dimensioned to fit within the counterbore; and a receiver fitting having a threaded bore and an inner bore having a sealing surface at an end opposite the threaded bore, the receiver fitting having a channel extending from the sealing surface to pass a fluid.

Additionally or alternatively, the seal body creates a fluid tight seal between the first endface of the seal body and the seating surface of the counterbore and between the second endface of the seal body and the sealing surface of the inner bore such that fluid conveyed through a channel of the tube and an axial opening of the seal body does not leak from the channel of the tube and the axial opening of the seal body.

Additionally or alternatively, the seal body is deformed over the front end of the tube body and compressed against the sealing surface of the receiver fitting.

The present teaching will now be described in more detail with reference to exemplary embodiments thereof as shown in the accompanying drawings. While the present teaching is described in conjunction with various embodiments and examples, it is not intended that the present teaching be limited to such embodiments. On the contrary, the present teaching encompasses various alternatives, modifications and equivalents, as will be appreciated by those of skill in the art. Those of ordinary skill having access to the teaching herein will recognize additional implementations, modifications and embodiments, as well as other fields of use, which are within the scope of the present disclosure as described herein.

High pressure fittings used in chromatographic systems typically include a compression member (e.g., a ferrule) and a compression screw to couple a fluid path in a tube to a fluid channel in a structure that includes a receiving port to receive the fitting. Hereinafter a "compression screw" may be a compression nut, or other feature configured to engage with a receiver fitting and compress or push on a fluidic tube into the receiver fitting. During installation, the installer slides the compression screw onto the tube and then slides the ferrule onto the tube before inserting the tube into the receiving port. The compression screw is tightened while the installer maintains a force on the tube to keep the endface of the tube in contact with a sealing surface at the bottom of the receiving port. The installer needs to know the proper installation technique. If installed improperly, or as a result of wear over time, damage can occur at the endface of the tube that is in contact with the sealing surface at the bottom of the receiving port. Further, because the components of the fittings are not fully contained in an assembled state, the components may be misplaced or mishandled prior to or during installation.

In brief overview, the present invention seeks to provide fittings for liquid chromatography systems that are fully contained and without loose parts. Embodiments of fittings disclosed herein are tool-free fittings that eliminate the need for installation tools and can be sufficiently tightened by hand. Further, fittings described herein may be configured to eliminate debris from galling during tightening. Fittings described herein may further be configured to eliminate pinch points within a female receiver fitting and minimize seal creep and further eliminate dead volume. The fittings described herein may be configured for multiple installations and tightening sequences without compromising connection integrity.

<FIG> shows an embodiment of a liquid chromatography system <NUM> for separating a sample into its constituents. The liquid chromatography system <NUM> can be an HPLC, UPLC, or SFC system. The liquid chromatography system <NUM> includes a solvent delivery system <NUM> in fluidic communication with a sample manager <NUM> (also called an injector or autosampler) through fluidic tube 16A. The solvent delivery system <NUM> includes pumps (not shown) in fluidic communication with solvent (or fluid) reservoirs <NUM> from which the pumps draw solvents through a fluidic conduit <NUM>, which may be a fluidic conduit, line, tube or channel. A chromatography column <NUM> is in fluidic communication with the sample manager <NUM> through fluidic tube 16B. Fluidic tube 16C couples the output port of the column <NUM> to a detector <NUM>, for example, a mass spectrometer, a UV detector, or any other detector. Through the fluidic tube 16C, the detector <NUM> receives the separated components from the column <NUM> and produces an output from which the identity and quantity of the analytes may be determined. As described herein, at various locations in the liquid chromatography system <NUM>, the fluidic tubes 16A, 16B, 16C are coupled to system components using high pressure fittings. Each fluidic tube <NUM> refers to a section of tubing rather a single tube. Each tubing section may comprise one tube or multiple tubes joined in series (e.g., by valves, tees, etc.).

The sample manager <NUM> includes an injector valve <NUM> with a sample loop <NUM>. The solvent manager <NUM> operates in one of two states: a load state and an injection state. In the load state, the position of the injector valve <NUM> is such that the solvent manager <NUM> loads the sample into the sample loop <NUM>; in the injection state, the position of the injector valve <NUM> changes so that solvent manager <NUM> introduces the sample in the sample loop <NUM> into the continuously flowing mobile phase arriving from the solvent delivery system <NUM>. With the injector valve <NUM> in the injection state, the mobile phase carries the sample into the column <NUM>. To accomplish this, the mobile phase arrives at the injector valve <NUM> through an input port <NUM> and leaves the injector valve with the sample through an output port <NUM>.

Various fittings according to principles of the invention as described below may be present within the liquid chromatography system <NUM>. For example, such fittings may be present where the fluidic tube 16A connects to the input port <NUM> of the injector valve <NUM>, where the fluidic tube 16B connects to the output port <NUM> of the injector valve <NUM> and to the column <NUM>, and where the fluidic tube 16C connects to the output end of the column <NUM> and to the detector <NUM>.

As shown in <FIG>, in some embodiments, for example, those in which the liquid chromatography system <NUM> is a CO2-based system, the sample manager <NUM> can further include an auxiliary valve <NUM> interposed between the solvent delivery system <NUM> and the injector valve <NUM> and between the injector valve <NUM> and the column <NUM>. In general, the auxiliary valve <NUM> provides a fluidic pathway through which the injector valve <NUM> may vent. In this embodiment, the fluidic tube 16A couples the solvent delivery system <NUM> to a first input port <NUM> of the auxiliary valve <NUM> and the fluidic tube 16B couples a second output port <NUM> of the auxiliary valve <NUM> to the column <NUM>. Fluidic tube 16D and 16E also couple the auxiliary valve <NUM> to the injector valve <NUM>; fluidic tube 16D connects a first output port <NUM> of the auxiliary valve <NUM> to the input port <NUM> of the injector valve <NUM>, and fluidic tube 16E connects the output port <NUM> of the injector valve <NUM> to a second input port <NUM> of the auxiliary valve <NUM>.

When the valves <NUM>, <NUM> are configured for sample injection, the arrows on the fluidic tube 16A and 16D show the direction of flow of the mobile phase towards the injector valve <NUM>; those arrows on the fluidic tube 16E and 16B correspond to the flow of the mobile phase carrying the sample from the injector valve <NUM> towards the column <NUM>.

Like the fluidic tube 16A, 16B, 16C described in connection with <FIG>, the additional fluidic tube 16D and 16E can also be coupled at their ends with fittings configured according to principles of the invention. More specifically, such fittings may be present where the fluidic tube 16D connects to the first output port <NUM> of the auxiliary valve <NUM> and to the input port <NUM> of the injector valve <NUM>, and where the fluidic tube 16E connects to the output port <NUM> of the injector valve <NUM> and to the second input port <NUM> of the auxiliary valve <NUM>.

<FIG> shows an example of how a fluidic coupling <NUM> is used to couple the fluidic tube 16B to the stator portion <NUM> of a rotary shear seal valve through one of the receiving ports <NUM>. Only one fitting connection is shown for clarity although it will be recognized that other fluidic tube 16B may be coupled to other receiving ports <NUM> of the stator portion <NUM> in a similar manner. The fluidic tube 16B is shown extending into a compression screw <NUM>. The compression screw <NUM> may also be described as a compression nut. While the fluidic tube 16B is shown for exemplary purposes in <FIG>, it should be understood that embodiments of the invention may be incorporated to connect any of the fluidic tubes 16A, 16B, 16C, 16D, 16E (generally <NUM>) and receivers of the liquid chromatography system <NUM> or any other fluidic system having fluidic fittings.

<FIG> depicts an exploded perspective view of an exemplary one of the fittings <NUM> of <FIG> in accordance with one embodiment. <FIG> depicts an exploded side view of the fitting of <FIG> in accordance with one embodiment. The fitting <NUM> may be is configured to connect to various liquid chromatography systems, such as <NUM> kilopounds per square inch (ksi), <NUM> MPa, systems, <NUM> ksi, <NUM> MPa, J Z systems, and/or <NUM> ksi, <NUM> GPa, systems. The fitting <NUM> may be configured for use anywhere in the liquid chromatography system <NUM> such as within pump(s), sample manager(s), column module(s) and/or detector(s) thereof. The fitting <NUM> may be a tool-free fitting that eliminates the need for installation tools and can be sufficiently tightened by hand. The fitting <NUM> may be configured to eliminate debris from galling during tightening. The fitting <NUM> may further be configured to eliminate pinch points within a female receiver fitting and minimize seal creep and further eliminate dead volume. The fitting <NUM> may be configured for multiple installations and tightening sequences without compromising connection integrity. All of the components of the fitting <NUM> may remain captive once assembled as described herein, with no loose parts capable of falling off or becoming lost during use.

The fitting <NUM> is shown including a seal body <NUM>, a collar <NUM>, a tube sleeve <NUM>, a compression screw <NUM>, a retainer ring <NUM> and an inner tube <NUM>. Hereinafter, the combination of the tube sleeve <NUM> and the inner tube <NUM> will be referred to as a tube assembly <NUM>, <NUM>. The fitting <NUM> is shown with its constituent parts prior to the manufacturing thereof which includes welding, and optionally also J Z polishing and/or crimping the various components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> in an assembled state, as described herein below and shown in <FIG>.

As shown in <FIG>, the seal body <NUM> of the fitting <NUM> extends between a first endface <NUM> and a second endface <NUM>. The seal body <NUM> includes an outer surface <NUM> and an inner bore <NUM>. The inner bore <NUM> of the seal body <NUM> may include an inner diameter in the range between. <NUM> inches, <NUM>, and. <NUM> inches, <NUM>, depending on, for example, the inner diameters of the tube assembly <NUM>, <NUM> and/or a female receiver fitting or the pressure requirement for a given application. The seal body <NUM> may be made of, for example, a high temperature polyimide or a polyether ether ketone (PEEK) material. The seal body <NUM> may further be made of a deformable material that is configured to compress under axial stress. However, in higher pressure applications, the seal body <NUM> may be made from a metallic material, such as Tantalum or Niobium metal. The yield strength of the material of the seal body <NUM> may be lower than the yield strength of the material of the components of the tube assembly <NUM>, <NUM>. The seal body <NUM> may be made of a creep resistant material and the seal body <NUM> may be, when assembled fully constrained by the collar <NUM> so as to prevent creep and prevent the need for periodic retightening of the fitting <NUM>.

The fitting <NUM> further includes the tube sleeve <NUM>. The tube sleeve <NUM> includes an outer surface <NUM>, and extends between a front endface <NUM> and a back end <NUM>. Extending within the tube sleeve <NUM> between the front endface <NUM> and the back end <NUM> is an inner channel <NUM> configured to receive the inner tube <NUM>. The tube sleeve <NUM> includes a reduced outer diameter portion <NUM> extending from the front endface <NUM>. The collar <NUM> is configured to extend over the reduced outer diameter portion <NUM> when the fitting <NUM> is assembled, as shown in <FIG>.

The tube sleeve <NUM> further includes a conical or tapered surface <NUM> expanding the outer diameter of the tube sleeve <NUM>. The conical or tapered surface <NUM> extends to a pushing surface <NUM> configured to receive an axial load from a surface of the compression screw <NUM>. The pushing surface <NUM> is a circumferential surface extending perpendicular to the axial direction of the tube sleeve <NUM> and the fitting <NUM>. The pushing surface <NUM> extends radially to a circumferential seat portion <NUM> configured to be received by a respective counterbore of the compression screw <NUM>. The conical or tapered surface <NUM>, the pushing surface <NUM> and the circumferential seat portion <NUM> are shown as an integral element of the tube sleeve <NUM>. However, in some embodiments, a tube sleeve <NUM> having the dimensions shown may be comprised of two or more separate components welded or otherwise attached together.

The tube sleeve <NUM> extends to the back end <NUM> where a circumferential channel <NUM> is located. The circumferential channel <NUM> may be configured to receive and retain the retainer ring <NUM> in a fixed position along the axial length of the tube sleeve <NUM>. The tube sleeve <NUM> is welded together with the inner tube <NUM> so that movement of the tube sleeve <NUM> imparts movement on the inner tube <NUM>.

The collar <NUM> is shown that is securable to each of the outer surface <NUM> of the tube sleeve <NUM>, particular at the reduced outer diameter portion <NUM>, and the outer surface <NUM> of the seal body <NUM>. The collar <NUM> extends between a first end <NUM> and a second end <NUM>. The collar <NUM> includes a thin wall portion <NUM> extending from the first end <NUM> and a thick wall portion <NUM> extending from the thin wall portion <NUM> to the second end <NUM>. A circumferential ridge <NUM> is defined by a difference in thickness between the thin wall portion <NUM> and the thick wall portion <NUM>. The circumferential ridge <NUM> defines a surface that is configured to contact the endface of the tube assembly <NUM>, <NUM>, and in particular, the front endface <NUM> thereof. Each of the thick wall portion <NUM> and the thin wall portion <NUM> may be configured to be press fit over the respective seal body <NUM> and the reduced outer diameter portion <NUM> of the tube sleeve <NUM>.

The compression screw <NUM> extends between a pushing endface <NUM> and a back end <NUM> and includes a channel <NUM> extending between the pushing endface <NUM> and the back end <NUM>. The channel <NUM> may be configured to receive a back portion of the tube sleeve <NUM>. A reduced diameter portion <NUM> of the channel <NUM> may be configured to cooperate with the retainer ring <NUM> to act as a stopper and prevent the tube assembly <NUM>, <NUM> from moving axially with respect to the compression screw <NUM>. In particular, the retainer ring <NUM> may have a larger outer diameter than the reduced diameter portion <NUM>, thereby preventing the retainer ring <NUM> from moving axially past the reduced diameter portion <NUM> toward the pushing endface <NUM>.

The compression screw <NUM> may be made of a gall resistant stainless steel material to prevent galling and prevent debris from being created by the friction between the compression screw <NUM> and a female receiver fitting, as shown in <FIG>. However, embodiments contemplated may be made of any metallic material. Materials that are not gall resistant are also contemplated. Non-gall-resistant materials may be gold plated to reduce galling.

The pushing endface <NUM> of the compression screw <NUM> includes a flat circumferential surface that is configured to abut and put an axial load on the pushing surface <NUM> of the tube sleeve <NUM>. Extending from the pushing endface <NUM> of the compression screw <NUM> is a counterbore <NUM> configured to receive and engage with the circumferential seat portion <NUM>. The compression screw <NUM> further includes threads <NUM> proximate the pushing endface <NUM> configured to interface with internal threads of a female receiver fitting, as shown in <FIG>.

The compression screw <NUM> includes an end knob <NUM> having a knurled grip portion <NUM>. The end knob <NUM> may be of a sufficient circumference and/or radius such that installations may be completed by hand without the use of an installation tool. The knurls are shown to be straight knurls, although other embodiments are contemplated such as diamond or diagonal knurls. While the shown embodiment includes the extended diameter manual tightening end knob <NUM>, other embodiments of aspects of the present invention may employ a typical tool-tightening end instead. For example, it is contemplated that the various embodiments of a seal body, collar and tube assembly consistent with the present disclosure may include either a tool-free or tool-required compression screw <NUM>.

The fitting <NUM> further includes the inner tube <NUM> extending between a first end <NUM> and a second end <NUM> and having a tube body <NUM> and a channel <NUM> extending therethrough. The inner tube <NUM> may be any length appropriate for a liquid chromatography application. The inner tube <NUM> may be made of, for example, stainless steel. By way of a specific dimensional example, the inner and outer dimensions of the inner tube <NUM> may be. <NUM> inches, <NUM>, and. <NUM> inches, <NUM>, respectively. However, various dimensions of the inner tube <NUM> may be provided depending on the type of liquid chromatography application and the pressures and volume flow rates under which the fitting <NUM> and inner tube <NUM> is configured to operate.

<FIG> depicts a side cross sectional view of the fitting <NUM> of <FIG> in accordance with one embodiment in an assembled state. As shown, the relative position of the compression screw <NUM> is secured with respect to the tube assembly <NUM>, <NUM> by the pushing surface <NUM> and circumferential seat portion <NUM> on one side, and the retainer ring <NUM> on the other side. Thus, the compression screw <NUM> may be axially restrained by these elements <NUM>, <NUM>, <NUM> relative to the tube assembly <NUM>, <NUM> while still being capable of axial rotation relative to the tube assembly <NUM>, <NUM>.

Further, the collar <NUM> is shown secured to each of the seal body <NUM> and the tube sleeve <NUM>. In one embodiment, the collar <NUM> may include two circumferential crimps, one located at the thin wall portion <NUM> for securing the collar <NUM> to the reduced outer diameter portion <NUM> and the other located at the thick wall portion <NUM> for securing the collar <NUM> to the seal body <NUM>. The two circumferential crimps may be a press fit to retain and secure the seal body <NUM> within the collar <NUM>. Once secured, the second endface <NUM> of the seal body <NUM> is configured to extend past the second end <NUM> of the collar. The amount that the second endface <NUM> extends over the second end <NUM> may vary depending on the application and material properties of the seal body. As shown in <FIG>, the extended second endface <NUM> of the seal body <NUM> may be configured to deform about the second end <NUM> of the collar <NUM> when the seal body <NUM> is under compression and pressed against a sealing surface with an axial load.

<FIG> depicts a perspective cutaway view of the fitting <NUM> of <FIG> in accordance with one embodiment prior to attachment of the collar <NUM> and seal body <NUM>. In particular, <FIG> shows the fitting <NUM> after attachment of the inner tube <NUM> and the tube sleeve <NUM> via a welding process. In particular, the inner tube <NUM> and the tube sleeve <NUM> may first be aligned at the ends thereof. A circumferential weld <NUM> may be applied at the endface created by each of the front endface <NUM> of the tube sleeve <NUM> and the first end <NUM> of the inner tube <NUM>. The weld <NUM> may be particularly located at the endface of the tube assembly <NUM>, <NUM>. Once welded, a polishing, sanding or smoothing process may be employed in order to flatten a polished endface surface <NUM>, as shown. The polished endface <NUM> provides a flat, smooth and/or uniform sealing surface that is configured to facilitate and improve sealing when the seal body <NUM> is pressed against the polished endface <NUM>. In one embodiment, the weld <NUM> may be the only form of attachment between the inner tube <NUM> and the tube sleeve <NUM>. In other embodiments, one or more additional welds may be located at one or more different axial locations along the inner tube <NUM> and the tube sleeve <NUM>.

<FIG> depicts a side cross sectional view of the fitting <NUM> of <FIG> attached to a receiver <NUM> before tightening in accordance with one embodiment. <FIG> depicts a side cross sectional view of the fitting <NUM> of <FIG> attached to the receiver <NUM> after tightening in accordance with one embodiment. The receiver <NUM> may be a female receiver fitting, or any other type of fitting configured to connect, mate or create a fluidic coupling with a male fitting such as the fitting <NUM>. The female receiver <NUM> is shown including a threaded bore <NUM> extending from an opening end. A tapered bore <NUM> extends from the threaded bore <NUM> deeper into the receiver <NUM>. An inner bore <NUM> extends from the tapered bore <NUM> to a sealing surface <NUM>. A channel <NUM> extends from the sealing surface <NUM> through which fluid from the fitting <NUM> is configured to be transported. As shown, the tapered surface <NUM> of the fitting <NUM> is shown aligned with the tapered bore <NUM> of the receiver <NUM> while the second endface <NUM> of the seal body <NUM> abuts the sealing surface <NUM> of the receiver <NUM>. As shown in <FIG>, when the seal body <NUM> is placed under axial compression by the tightening of the compression screw <NUM> within the female receiver <NUM>, the seal body <NUM> is configured to deform over the second end <NUM> of the collar <NUM>, as depicted with an expanded circumferential portion <NUM>.

Methods of manufacturing the fitting <NUM> are also contemplated in accordance with the shown embodiment and Figures. For example, a method of manufacturing the fitting <NUM> includes welding a tube sleeve, such as the tube sleeve <NUM>, and an inner tube, such as the inner tube <NUM>, at an endface of each of the tube sleeve and the inner tube, such as the front endface <NUM> and the first end <NUM>, to create a tube assembly having a welded tube assembly endface, such as the polished surface <NUM>. Method of manufacturing may also include polishing the welded tube assembly endface after the welding of the ends of the tube sleeve and the inner tube. Still further, methods may include abutting a surface of a seal body, such as the seal body <NUM>, to the welded tube assembly endface and securing a collar, such as the collar <NUM>, to an outer surface of the tube sleeve and an outer surface of the seal body. This securing may include, for example, press fitting the collar to each of the outer surface of the tube sleeve and the outer surface of the seal body. The assembly of the fitting in accordance with the method may thereby include maintaining a fluid tight seal between the surface of the seal body and the welded tube assembly endface such that fluid conveyed through the inner tube and an axial opening of the seal does not leak between the tube sleeve, the inner tube, and the collar.

Other methods contemplated include creating a fluidic coupling in a chromatography system such as a liquid chromatography system. Methods may include providing a fitting, such as the fitting <NUM>, and fluidically coupling the fitting to a receiver fitting of a liquid chromatography system by hand tightening a compression screw of the fitting, such as the compression screw <NUM>, without a tightening tool, such as wrench of the like. Methods include maintaining a fluid tight seal between a first endface of a seal body, such as the first endface <NUM> of the seal body <NUM>, and an endface of a tube assembly, such as the endface <NUM> of the tube assembly <NUM>, <NUM>. Methods may include conveying fluid through an inner tube, such as the inner tube <NUM>, and an axial opening of the seal body, such as the inner bore <NUM>. Methods may further include avoiding any leaking of the fluid between a tube sleeve, an inner tube, and a collar of the fitting, such as the tube sleeve <NUM>, inner tube <NUM> and collar <NUM> of the fitting <NUM>. Methods may include deforming the seal body over an end of the collar when compressed against a surface of a receiver fitting, such as the deformation shown in <FIG>.

<FIG> depicts an exploded perspective view of another exemplary fitting <NUM> in accordance with one embodiment. <FIG> depicts a side cross sectional view of the fitting of <FIG> in accordance with one embodiment. Like the fitting <NUM> the fitting <NUM> may be deployed in the manner described in <FIG> in a liquid chromatography system or any chromatography system. The fitting <NUM> may be is configured to connect to various liquid chromatography systems, such as <NUM> kilopounds per square inch (ksi), <NUM> MPa, systems, <NUM> ksi, <NUM> MPa, systems, and/or <NUM> ksi <NUM> GPa, systems. Similar to the fitting <NUM>, the fitting <NUM> may be a tool-free fitting that eliminates the need for installation tools and can be sufficiently tightened by hand. The fitting <NUM> may be configured to eliminate debris from galling during tightening. The fitting <NUM> may further be configured to eliminate pinch points within a female receiver fitting and minimize seal creep and further eliminate dead volume. The fitting <NUM> may be configured for multiple installations and tightening sequences without compromising connection integrity. The fitting <NUM> is shown including a compression screw <NUM>, a push ring <NUM>, a retainer cap <NUM>, a seal body <NUM> and a tube <NUM>. Unlike the fitting <NUM>, the fitting <NUM> does not include a tube sleeve, but rather includes only the single tube <NUM>.

The compression screw <NUM> extends between a front end <NUM> and a back end <NUM> and includes a channel <NUM> extending between the front end <NUM> and the back end <NUM>. The channel <NUM> may be configured to receive the tube <NUM>. A reduced diameter portion <NUM> of the channel <NUM> may be configured to receive the tube <NUM> with a clearance fit that allows the tube <NUM> to slide through the reduced diameter portion <NUM>. The compression screw <NUM> includes external threads <NUM> configured to be received by female threads of a female receiver fitting, as shown in in an exemplary embodiment in <FIG>.

The compression screw <NUM> is a first counterbore <NUM> extending from the back end <NUM> having a first circumference. The first counterbore <NUM> extends to a first seating surface <NUM>. A second counterbore <NUM> extends from the first counterbore <NUM> further from the back end <NUM> having a second circumference that is less than the first circumference. The second counterbore <NUM> extends to a second seating surface <NUM>. The second counterbore <NUM> may be configured to receive the push ring <NUM> with a clearance fit that allows the compression screw <NUM> to freely rotate about the push ring <NUM>. The first counterbore <NUM> may be configured to receive a portion of the retainer cap <NUM> with an interference or press fit attachment so that rotation of the compression screw <NUM> causes rotation of the retainer cap <NUM>. In other embodiments, the retainer cap <NUM> may be configured to be welded, adhered or otherwise permanently attached to the end of the compression screw <NUM>.

The push ring <NUM> may be made of a stainless steel or other metallic material that can be welded to the outer surface of the tube <NUM>. Prior to attachment, the push ring <NUM> may include a circular middle opening configured to receive the tube <NUM>. When welded or otherwise attached or fixed to the tube <NUM>, the push ring <NUM> creates a tube having a greater diameter portion (i.e. the push ring <NUM>) that is configured to be moved or pushed axially with the compression screw <NUM>. The push ring <NUM> may be dimensioned to fit into the second counterbore <NUM> of the compression screw <NUM> with clearance to allow for rotation of the push ring <NUM> about the compression screw <NUM>. In other embodiments, the push ring <NUM> may be in integral circumferential protrusion, ridge, or other greater diameter portion of the tube <NUM> that may similarly fit into the second counter bore <NUM> of the compression screw <NUM>.

The retainer cap <NUM> includes a main body <NUM> having a circumference that covers most or all of the surface area of the back end <NUM> of the compression screw <NUM>. A retainer cap <NUM> includes a circumferential extended portion <NUM> extending from the main body <NUM> of the retainer cap <NUM>. The circumferential extending portion <NUM> may a circumference that corresponds to the circumference of the first counterbore <NUM> of the compression screw <NUM>. The circumferential extending portion <NUM> is configured to attach to the back end of the compression screw <NUM> within the first counterbore <NUM> in a press fit or interference fit arrangement. The circumferential extending portion <NUM> may further be attached to the compression screw <NUM> with an adhesive or weld if necessary. Whatever the embodiment, the retainer cap <NUM> may be configured to rotate with the compression screw <NUM>. The retainer cap <NUM> further includes a circumferential narrow ring contact portion <NUM> extending from the circumferential extending portion <NUM> and configured to make contact with the push ring <NUM>. This contact portion <NUM> may be configured to retain the push ring <NUM> firmly in place between the retainer cap <NUM> and the second seating surface <NUM> of the second counterbore <NUM>, while still allowing rotation between the push ring <NUM> and the compression screw <NUM> and retainer cap <NUM>.

The seal body <NUM> of the fitting <NUM> extends between a first endface <NUM> and a second endface <NUM>. The seal body <NUM> includes an outer surface and an inner bore <NUM>. The inner bore <NUM> of the seal body <NUM> may include an inner diameter in the range between. <NUM> inches, <NUM>, and. <NUM> inches, <NUM>, depending on, for example, the inner diameters of the tube <NUM> and/or a female receiver fitting or the pressure requirement for a given application. The seal body <NUM> may be made of, for example, a high temperature polyimide or a polyether ether ketone (PEEK) material. The seal body <NUM> may further be made of a deformable material that is configured to compress under axial stress. However, in higher pressure applications, the seal body <NUM> may be made from a metallic material, such as Tantalum or Niobium metal. The yield strength of the material of the seal body <NUM> may be lower than the yield strength of the material of the components of the tube <NUM>. The seal body <NUM> may be made of a creep resistant material and the seal body <NUM> may be, when assembled fully constrained by the tube <NUM> so as to prevent creep and prevent the need for periodic retightening of the fitting <NUM>.

The tube <NUM> includes a body extending between a first end <NUM> and a second end <NUM> and having a channel <NUM> extending therethrough. The tube <NUM> may be any length appropriate for a liquid chromatography application. The tube <NUM> may be made of, for example, stainless steel. By way of a specific dimensional example, the inner and outer dimensions of the tube <NUM> may be. <NUM> inches, <NUM>, and. <NUM> inches, <NUM>, respectively. However, various dimensions of the tube <NUM> may be provided depending on the type of liquid chromatography application and the pressures and volume flow rates under which the fitting <NUM> and tube <NUM> is configured to operate.

The tube <NUM> may further include a counterbore <NUM> extending from the first end <NUM> to a seating surface <NUM>. The outer surface of the seal body <NUM> may be dimensioned to fit within the counterbore <NUM> of the tube <NUM>. In particular, the counterbore <NUM> may be a narrower or thinner portion of the wall of the tube <NUM> relative to the rest of the length of the tube <NUM> that extends from the seating surface <NUM> toward the first end <NUM>. This narrow or thinner portion may be configured to receive the second endface <NUM> of the seal body in a press fit, friction fit, or interference fit relationship. When seated in the counterbore <NUM>, the seal body <NUM> may have a length between its first and second endfaces <NUM>, <NUM> that is greater than a length of the counterbore <NUM> such that the seal body <NUM> extends from the first end <NUM> of the tube <NUM>.

<FIG> depicts a side cross sectional view of the fitting <NUM> of <FIG> attached to the receiver <NUM> after tightening in accordance with one embodiment. <FIG> depicts a side cross sectional view of the fitting <NUM> of <FIG> attached to the receiver <NUM> after tightening in accordance with one embodiment. While the fitting <NUM> may be configured to attached to the same type of receiver as the fitting <NUM> described above, the fittings <NUM>, <NUM> may be dimensioned to create fluidic couplings with various female receiver fittings. As shown, a tapered surface <NUM> of the fitting <NUM> is shown aligned with the tapered bore <NUM> of the receiver <NUM> while the second endface <NUM> of the seal body <NUM> abuts the sealing surface <NUM> of the receiver <NUM>. The outer threads <NUM> of the compression screw <NUM> are engaged with the threads <NUM> of the receiver fitting <NUM>. As shown in <FIG>, when the seal body <NUM> is placed under axial compression by the tightening of the compression screw <NUM> within the female receiver <NUM> via engagement of the threads <NUM>, <NUM>. This tightening creates an axial compression on the seal body <NUM>, which is configured to deform over the first end <NUM> of the tube <NUM>, as depicted with an expanded circumferential portion <NUM>.

Methods of fluidic coupling using a fitting such as the fitting <NUM> are contemplated. For example, methods may include providing a fitting, such as the fitting <NUM>. Methods may include fluidically coupling the fitting to a receiver fitting, such as the receiver <NUM>, of a liquid chromatography system by hand tightening the compression screw without a tightening tool. Methods may include maintaining a fluid tight seal between the first endface of the seal body and the seating surface of the tube assembly and conveying fluid through the inner tube and an axial opening of the seal. Methods may include deforming the seal body over the front end of the tube when compressed against a surface of a receiver fitting and passing a fluid through the tube, the seal body and the receiver fitting.

Claim 1:
A fitting (<NUM>) for fluidic coupling in a chromatography system comprising:
a compression screw (<NUM>) including an axial bore (<NUM>), a threaded portion (<NUM>), and a drive end (<NUM>);
a tube assembly (<NUM>, <NUM>) including a tube sleeve (<NUM>) and an inner tube (<NUM>) disposed through the tube sleeve (<NUM>), the tube sleeve (<NUM>) and the inner tube (<NUM>) each extending to an endface (<NUM>) of the tube assembly (<NUM>, <NUM>), the tube sleeve (<NUM>) including an outer surface (<NUM>), wherein the tube sleeve (<NUM>) and the inner tube (<NUM>) are welded together at the endface (<NUM>);
a seal body (<NUM>) extending between a first endface (<NUM>) and a second endface (<NUM>), the first endface (<NUM>) abutting the endface (<NUM>) of the tube assembly (<NUM>, <NUM>), the seal body (<NUM>) including an outer surface (<NUM>); and
a collar (<NUM>) secured to the outer surface (<NUM>) of the tube sleeve (<NUM>) and the outer surface (<NUM>) of the seal body (<NUM>).