Patent Application
20200292108
The present disclosure relates generally to fitting assemblies and fluidic connection systems, such as those used in connecting components of liquid chromatography systems and other analytical instrument systems, and, more specifically, to fitting assemblies and fluidic connection systems for connecting tubing to ports.
Liquid chromatography (LC) is a well-known technique for separating the constituent elements in a given sample. In a conventional LC system, a liquid solvent (referred to as the “mobile phase”) is introduced from a reservoir and is pumped through the LC system. The mobile phase exits the pump under pressure. The mobile phase then travels via tubing to a sample injection valve. As the name suggests, the sample injection valve allows an operator to inject a sample into the LC system, where the sample will be carried along with the mobile phase.
In a conventional LC system, the sample and mobile phase pass through one or more filters and often a guard column before coming to the column. A typical column usually consists of a piece of steel tubing which has been packed with a “packing” material. The “packing” consists of the particulate material “packed” inside the column. It usually consists of silica- or polymer-based particles, which are often chemically bonded with a chemical functionality. The packing material is also known as the stationary phase. One of the fundamental principles of separation is the mobile phase continuously passing through the stationary phase. When the sample is carried through the column (along with the mobile phase), the various components (solutes) in the sample migrate through the packing within the column at different rates (i.e., there is differential migration of the solutes). In other words, the various components in a sample will move through the column at different rates. Because of the different rates of movement, the components gradually separate as they move through the column. Differential migration is affected by factors such as the composition of the mobile phase, the composition of the stationary phase (i.e., the material with which the column is “packed”), and the temperature at which the separation takes place. Thus, such factors will influence the separation of the sample's various components.
Once the sample (with its components now separated) leaves the column, it flows with the mobile phase past a detector. The detector detects the presence of specific molecules or compounds. Two general types of detectors are used in LC applications. One type measures a change in some overall physical property of the mobile phase and the sample (such as their refractive index). The other type measures only some property of the sample (such as the absorption of ultraviolet radiation). In essence, a typical detector in a LC system can measure and provide an output in terms of mass per unit of volume (such as grams per milliliter) or mass per unit of time (such as grams per second) of the sample's components. From such an output signal, a “chromatogram” can be provided; the chromatogram can then be used by an operator to determine the chemical components present in the sample.
In addition to the above components, a LC system will often include filters, check valves, a guard column, or the like in order to prevent contamination of the sample or damage to the LC system. For example, an inlet solvent filter may be used to filter out particles from the solvent (or mobile phase) before it reaches the pump. A guard column is often placed before the analytical or preparative column; i.e., the primary column. The purpose of such a guard column is to “guard” the primary column by absorbing unwanted sample components that might otherwise bind irreversibly to the analytical or preparative column.
In practice, various components in an LC system may be connected by an operator to perform a given task. For example, an operator will select an appropriate mobile phase and column, then connect a supply of the selected mobile phase and a selected column to the LC system before operation. In order to be suitable for high performance liquid chromatography (HPLC) applications, each connection must be able to withstand the typical operating pressures of the HPLC system. If the connection is too weak, it may leak. Because the types of solvents that are sometimes used as the mobile phase are often toxic and because it is often expensive to obtain and/or prepare many samples for use, any such connection failure is a serious concern.
It is fairly common for an operator to disconnect a column (or other component) from a LC system and then connect a different column (or other component) in its place after one test has finished and before the next begins. Given the importance of leak-proof connections, especially in HPLC applications, the operator must take time to be sure the connection is sufficient. Replacing a column (or other component) may occur several times in a day. Moreover, the time involved in disconnecting and then connecting a column (or other component) is unproductive because the LC system is not in use and the operator is engaged in plumbing the system instead of preparing samples or other more productive activities. Hence, the replacement of a column in a conventional LC system involves a great deal of wasted time and inefficiencies.
Given concerns about the need for leak-free connections, conventional connections have been made with stainless steel tubing and stainless steel end fittings. More recently, however, it has been realized that the use of stainless steel components in a LC system have potential drawbacks in situations involving biological samples. For example, the components in a sample may attach themselves to the wall of stainless steel tubing. This presents problems because the detector's measurements (and thus the chromatogram) of a given sample may not accurately reflect the sample if some of the sample's components or ions remain in the tubing, and do not pass the detector. Perhaps of even greater concern, however, is the fact that ions from the stainless steel tubing may detach from the tubing and flow past the detector, thus leading to potentially erroneous results. Additionally, ions can easily bind to biological compounds of interest, resulting in changes to the molecules that affect their retention time in the column. Hence, there is a need for “biocompatible” connections through the use of a material that is chemically inert with respect to such “biological” samples and the mobile phase used with such samples so that ions will not be released by the tubing and thus contaminate the sample.
In many applications using selector/injector valves to direct fluid flows, and in particular in liquid and gas chromatography, the volume of fluids is small. This is particularly true when liquid or gas chromatography is being used as an analytical method as opposed to a preparative method. Such methods often use capillary columns and are generally referred to as capillary chromatography. In capillary chromatography, both gas phase and liquid phase, it is often desired to minimize the internal volume of the selector or injector valve. One reason for this is that a valve having a large volume will contain a relatively large volume of liquid, and when a sample is injected into the valve the sample will be diluted, decreasing the resolution and sensitivity of the analytical method.
Micro-fluidic analytical processes also involve small sample sizes. As used herein, sample volumes considered to involve micro-fluidic techniques can range from as low as volumes of only several picoliters or so, up to volumes of several milliliters or so, whereas more traditional LC techniques, for example, historically often involved samples of about one microliter to about 100 milliliters in volume. Thus, the micro-fluidic techniques described herein involve volumes one or more orders of magnitude smaller in size than traditional LC techniques. Micro-fluidic techniques can also be expressed as those involving fluid flow rates of about 0.5 ml/minute or less.
Most conventional HPLC systems include pumps which can generate relatively high pressures of up to around 5,000 psi to 6,000 psi or so. In many situations, an operator can obtain successful results by operating a LC system at “low” pressures of anywhere from just a few psi or so up to 1,000 psi or so. More often than not, however, an operator will find it desirable to operate a LC system at relatively “higher” pressures of over 1,000 psi.
Another, relatively newer liquid chromatography form is Ultra High Performance Liquid Chromatography (UHPLC) in which system pressure extends upward to about 1400 bar or 20,000 psi or so, or even more. In order to achieve greater chromatographic resolution and higher sample throughput, the particle size of the stationary phase has become extremely small. A stationary phase particle as small as 1 micron is common; the resulting high column packing density leads to substantially increased system pressure at the head of the column. Both HPLC and UHPLC are examples of analytical instrumentation that utilize fluid transfer at elevated pressures. For example, in U.S. Patent Publication No. 2007/0283746 A1, published on Dec. 13, 2007 and titled “Sample Injector System for Liquid Chromatography,” an injection system is described for use with UHPLC applications, which are said to involve pressures in the range from 20,000 psi to 120,000 psi. In U.S. Pat. No. 7,311,502, issued on Dec. 25, 2007 to Gerhardt, et al., and titled “Method for Using a Hydraulic Amplifier Pump in Ultrahigh Pressure Liquid Chromatography,” the use of a hydraulic amplifier is described for use in UHPLC systems involving pressures in excess of 25,000 psi. In U.S. Patent Publication No. 2005/0269264 A1, published on Dec. 8, 2005 and titled “Chromatography System with Gradient Storage and Method for Operating the Same,” a system for performing UHPLC is disclosed, with UHPLC described as involving pressures above 5,000 psi (and up to 60,000 psi). Applicants hereby incorporate by reference as if fully set forth herein U.S. Pat. No. 7,311,502 and US Patent Publications Nos. 2007/0283746 A1 and 2005/0269264 A1.
As noted, liquid chromatography (as well as other analytical) systems, including HPLC or UHPLC systems, typically include several components. For example, such a system may include a pump; an injection valve or autosampler for injecting the analyte; a precolumn filter to remove particulate matter in the analyte solution that might clog the column; a packed bed to retain irreversibly adsorbed chemical material; the HPLC column itself; and a detector that analyzes the carrier fluid as it leaves the column. These various components may typically be connected by a miniature fluid conduit, or tubing, such as metallic or polymeric tubing, usually having an internal diameter of 0.001 to 0.040 inch.
All of these various components and lengths of tubing are typically interconnected by threaded fittings. Fittings for connecting various LC system components and lengths of tubing are disclosed in prior patents, for example, U.S. Pat. Nos. 5,525,303; 5,730,943; and 6,095,572, the disclosures of which are herein all incorporated by reference as if fully set forth herein. Often, a first internally threaded fitting seals to a first component with a ferrule or similar sealing device. The first fitting is threadedly connected through multiple turns by hand or by use of a wrench or wrenches to a second fitting having a corresponding external fitting, which is in turn sealed to a second component by a ferrule or other seal. Disconnecting these fittings for component replacement, maintenance, or reconfiguration often requires the use of a wrench or wrenches to unthread the fittings. Although a wrench or wrenches may be used, other tools such as pliers or other gripping and holding tools are sometimes used. It will be understood by those skilled in the art that, as used herein, the term “LC system” is intended in its broad sense to include all apparatus and components in a system used in connection with liquid chromatography, whether made of only a few simple components or made of numerous, sophisticated components which are computer controlled or the like. Those skilled in the art will also appreciate that an LC system is one type of an analytical instrument (AI) system. For example, gas chromatography is similar in many respects to liquid chromatography, but obviously involves a gas sample to be analyzed. Such analytical instrument systems include high performance or high pressure liquid chromatography systems, an ultra high performance or ultra high pressure liquid chromatography system, a mass spectrometry system, a microflow chromatography system, a nanoflow chromatography system, a nano-scale chromatography system, a capillary electrophoresis system, a reverse-phase gradient chromatography system, or a combination thereof. Although the following discussion focuses on liquid chromatography, those skilled in the art will appreciate that much of what is said also has application to other types of AI systems and methods.
Increasing pressure requirements in liquid chromatography have necessitated the use of high pressure fluidic components. For many applications regular stainless steel tubing can be used to withstand the high pressure. However, for some types of analyses (e.g., biological testing and metal/ion analysis), stainless steel or other metals are not desired in the fluid path as the metal could interfere with the testing. Additionally, there are some fields of use (e.g., nano-scale or nano-volume analysis), that require very small inside diameters to accommodate the extremely low volumes required by these applications. Such small inside diameters are typically not available in stainless steel or other high pressure tubing.
In high-performance liquid chromatography (HPLC), ultra high-performance liquid chromatography (UHPLC), and other high-pressure analytic chemistry applications, various system components and their fluidic connections must be able to withstand pressures of 15,000 to 20,000 psi or so. The types of fluidic connection systems between the tubes that carry fluids and the ports that receive fluids in these high-pressure applications are limited. Many fluidic connection systems rely on cone-shaped, threaded, or welded fittings to attach a tube to a receiving port. These types of connections sometimes may have drawbacks, however. For example, the size of cone-shaped fittings and threaded fittings are dependent on the type and size of any given port, which makes quickly interchanging a tube fitted with a particular cone or threaded fitting between various ports difficult. Other compression-based fittings have been employed to address this problem. Such fittings often employ a ferrule or a lock ring to help secure one end of a tube to a receiving port. However, ferrules and lock rings can become deformed after multiple uses (e.g., by connecting, disconnecting, and reconnecting to various ports). This is especially true in high-pressure applications, where a fluid-tight seal is essential, and where a ferrule or lock ring may be more likely to become deformed in creating such a seal.
For example, published U.S. Patent Application No. 2013/0043677, titled “Tube and Pipe End Cartridge Seal,” published on Feb. 21, 2013, describes a tube and pipe end cartridge seal for use at high pressures, which relies on a fitting body (including ferrule fittings) to effectuate a seal with the axial end of a tube. Moreover, a dimple is forged on the annular end of the tube face to further effectuate the seal. Likewise, U.S. Pat. No. 6,056,331, titled “Zero Dead Volume Tube to Surface Seal,” issued to Bennett et al. on May 2, 2000, describes an apparatus for connecting a tube to a surface using a body, a ferrule, and a threaded fitting. Although Bennett et al. discloses a type of tube face-sealing apparatus, the apparatus of Bennet et al. relies on a threaded fitting and a ferrule. Similarly, published U.S. Patent Application No. 2012/0061955, titled “Plug Unite and Connection System for Connecting Capillary Tubes, Especially for High-Performance Liquid Chromatography,” published on Mar. 15, 2012, discloses a plug unit connection system for capillary tubes, wherein a seal is provided at the interface between a capillary tube and a bushing unit, instead of at the location of a ferrule or conical fitting. However, U.S. Patent Application No. 2012/0061955 relies on the use of a pressure piece similar to a ferrule to ensure that enough axial force can be generated to obtain a seal at the tube face.
Connection assemblies which attempt to effectuate a seal for high-pressure applications can require a significant amount of torque to effectuate a fluid-tight seal, making the creation of such seals difficult without the use of additional tools and increasing the risk of damage to the fitting assembly or its components due to overtightening. Moreover, experience suggests that many users do not like to use various tools to connect or disconnect tubing from components such as those in various AI systems. It is believed that users often apply different amounts of torque to connect or disconnect tubing and the components in such systems, thus resulting in potential problems caused by over-tightening or under-tightening (e.g., leakage or loss of sealing when the fluid is under pressure).
One example of a flat-bottomed or face-sealing connection assembly is provided by U.S. Pat. No. 8,696,038, titled “Flat Bottom Fitting Assembly” and issued on Apr. 15, 2014 to Nienhuis. Nienhuis teaches a type of flat bottom assembly which includes a flat-sided ferrule, and wherein the assembly including the ferrule and the tube can be pressed against a flat bottom port. Another example of a flat-bottomed or face-sealing connection assembly is provided by published U.S. Patent Application No. 2012/0024411, titled “Biocompatible Tubing for Liquid Chromatography Systems,” which was published on Feb. 2, 2012 and was filed on behalf of Hahn et al. The Hahn et al. published patent application describes tubing having an inner layer and an outer layer, and in which the inner layer can be biocompatible material such as polyetheretherketone (PEEK) and the outer layer may be a different material, and in which an end of the tubing may be flared or otherwise adapted to have a larger outer diameter than other portions of the tubing. The current state of the art for high pressure connections in both HPLC and UHPLC is to utilize coned ports along with some form of ferrule and nut combination with tubing. The nut translates rotational torque into axial load that is translated to the ferrule. The load causes the ferrule to deform/deflect and grip the tubing, creating a seal. The tube is typically forced into the bottom of the coned port, but there is not currently a mechanism to ensure there is not a gap or space at the port bottom.
The space at the bottom of the port is a concern for those performing liquid chromatography experiments due to the potential to negatively influence the results with carry over and band broadening. Carry over is just as it sounds, analyte from one test is carried over to the next. Carry over can produce very unstable results for obvious reasons. Band broadening is when the peaks identifying a substance become less symmetric and make identification more difficult when peaks of different molecules have similar retention times.
One issue with conventional ferrules used with coned ports is that the torque required to deform/deflect is typically above finger tight levels in order to achieve UHPLC pressures (e.g., above 12,000 psi or so). It is desirable to remove tools from the lab by making them unnecessary for making and breaking fluidic connections and it is advantageous to have fittings that can be connected simply with the fingers rather than tools.
European Patent No. EP 2564104 describes a sealing system for use at high pressure. End-face seals minimize the sealing radius and therefore allow various fittings—including known ferrule fittings—to be used in high-pressure systems. End-face seals at such high pressure may require smooth surfaces, however. In order to reduce cost, an end-face preparation tool may be required to forge a dimple into the end face to mechanically deform and smooth the surface.
U.S. Pat. No. 6,056,331 describes an apparatus that is composed of three components, a body, a ferrule, and a threaded fitting. The ferrule is compressed onto a tube and a seal is formed between the tube and a device retained in the body by threading the fitting into the body which provides pressure that seals the face of the ferrule to a mating surface on the device. This seal may be used at elevated temperatures, depending on the materials used. This fitting was developed for use with micro-machined silicon wafers used in capillary gas chromatography.
U.S. Pat. Nos. 5,525,303, 5,730,943, 6,056,0331, 6,095,572, 6,056,331, 7,311,502, 8,696,038, European Patent No. EP2564104, and published U.S. Patent Application Nos. 2005/0269264, 2007/0283746, 2012/0024411, 2012/0061955, and 2013/0043677 are hereby incorporated by reference as if fully set forth herein.
It is therefore an object of the present disclosure to provide a fluidic connection system useful for high-pressure applications. The system can provide a sealing connection without the use of additional parts such as ferrules, locking rings, or other fittings. It is a further object of the present disclosure to provide a fluidic connection system, wherein the axial force necessary to create an effective seal for high-pressure applications can be generated manually, with minimal torque and without the use of tools. It is a further object of the present disclosure to provide a fluidic connection system which is flexible and can be quickly and easily connected and disconnected with various tubes and ports without damaging the connection system.
In one embodiment of the present disclosure, a fitting assembly comprises a nut having a passageway extending therethrough and having a first end and a second end, wherein said nut has an externally threaded portion near the second end of said nut, a tube having a portion extending through the passageway in said nut, wherein said tube comprises an inner layer and an outer layer, each having a first end and a second end and each layer having an inside diameter and an outside diameter, wherein the outer layer of said tube has an inside diameter greater than the outside diameter of the inner layer, and wherein the first end of said tube comprises a tip portion, wherein the tip portion has an inner diameter and an outer diameter and a portion of the inner layer of said tube is located within the inner diameter of the tip portion, and wherein at least one of a first end of the tip portion and the first end of the inner layer define a surface adapted to form a seal with a port, and a sleeve having a passageway therethrough and having a first end and a second end, with at least a portion of the first end of said sleeve adapted to fit against a surface of said nut and at least a portion of the second end of said sleeve located between the outside diameter of a portion of the inner layer of said tube and the inner diameter of the tip portion of said tube, wherein the tip portion of said tube extends over at least a portion of the inner layer of said tube, at least a portion of the outer layer of said tube, and over at least a portion of the sleeve. The outer layer of said tube may comprise a first material and the inner layer of said tube may comprise a second material, and the two materials may be different. The fitting assembly according to claim 2 wherein the first material comprises a material different than the second material. The sleeve and the outer tube layer may each comprise a metal material, and the inner layer of said tube and the tip of said tube may comprise a biocompatible material, such as polyetheretherketone (PEEK). In addition, the sleeve may further comprise a retention feature, such as a lip. The tip of the tube may be overmolded over and onto a portion of the inner tube layer.
In another embodiment of the present disclosure, a tubing assembly is provided, which comprises a tube having an inner layer and an outer layer, each having a first end and a second end and each having an inside diameter and an outside diameter, wherein said tube further comprises a tip portion having a first end, and wherein at least one of a first end of the inner layer of said tube and the first end of the tip portion of said tube defines a substantially flat surface adapted to contact and form a seal against a flat-bottomed port, and a sleeve having a passageway therethrough and having a first end and a second end, with at least a first portion of said sleeve located between the outside diameter of a portion of the outer layer of said tube and a second portion of said sleeve located between the inner diameter of a portion of the tip portion of said tube and the outside diameter of the inner layer of said tube. In such a tubing assembly, the sleeve may comprise a metal such as stainless steel, the inner layer of said tube may comprise a biocompatible material such as PEEK, the outer layer of said tube may comprise a material such as stainless steel, and the tip portion of said tube may comprises a biocompatible material, such as PEEK.
In another embodiment, an analytical instrument system is provided which comprises at least two components having fluid communication therebetween, wherein at least one of said components has a flat-bottomed port having a face, a tube comprising an inner layer and an outer layer, each having a first end and a second end and each having an inside diameter and an outside diameter, said tube further comprising a tip portion, wherein a first end of the tip portion of said tube defines a substantially flat surface, and wherein the tip portion of said tube has a greater outside diameter than the outside diameter of the inner layer, a sleeve having a passageway therethrough and having a first end and a second end, with at least a portion of the first end of said sleeve located between the outside diameter of a portion of the inner layer of said tube and the inner diameter of a portion of the tip portion of said tube, wherein the tip portion of said tube extends over at least a portion of the inner layer and over at least a portion of the sleeve, wherein the first end of the tip portion and the face of the flat-bottomed port are in a sealing engagement, and wherein either or both of said components comprise any one of the following: pumps, columns, filters, guard columns, injection valves, and other valves, detectors, pressure regulators, reservoirs, degassers, unions, tees, crosses, adapters, splitters, sample loops, and/or connectors. Both the inner layer and the tip portion of said tube may comprise a biocompatible material, such as PEEK.
In another embodiment, a fitting assembly is provided in which a nut has one or more slots, which can extend the longitudinal length of the nut and which can extend radially from the passageway through the nut to the exterior of the nut. The nut can have one or more such slots, and the slots can extend along only a portion of the longitudinal length of the nut if desired. In addition, the slot can be adapted so that tubing can be easily inserted into the interior passageway of the nut by an operator, or can be easily removed from the nut by an operator. The slot is adapted so that a tube or a portion of a tube can be easily inserted into or removed from the nut through the slot.
Each of the fitting assembly, tubing assembly, and analytical instrument system of the present disclosure are adapted to provide at least one sealing connection for a fluid connection in which the fluid has a pressure of between 0 psi and 25,000 psi, between 1,000 psi and 20,000 psi, and/or between 2,500 psi and 10,000 psi. Such a sealing connection can be made by a user without the use of tools or ferrules, and is adapted so that it can be made with a flat-bottomed port.
These and numerous other features, objects and advantages of the present disclosure will become readily apparent to those skilled in the art upon a reading of the detailed description, claims and the drawings.
In
When the sample is injected via sample injection valve 110 in the LC system, the sample is carried by the mobile phase through the tubing into the column 115. As is well known in the art, the column 115 contains a packing material which acts to separate the constituent elements of the sample. After exiting the column 115, the sample (as separated via the column 115) then is carried to and enters a detector 117, which detects the presence or absence of various chemicals. The information obtained by the detector 117 can then be stored and used by an operator of the LC system to determine the constituent elements of the sample injected into the LC system. Those skilled in the art will appreciate that
Preferably, for an LC system to be biocompatible, the various components (except where otherwise noted) that may come into contact with the effluent or sample to be analyzed are made of the synthetic polymer polyetheretherketone, which is commercially available under the trademark “PEEK” from Victrex. The polymer PEEK has the advantage of providing a high degree of chemical inertness and therefore biocompatibility; it is chemically inert to most of the common solvents used in LC applications, such as acetone, acetonitrile, and methanol (to name a few). PEEK also can be machined by standard machining techniques to provide smooth surfaces. Those skilled in the art will appreciate that other polymers may be desirable in certain applications.
Referring now to
As shown in
Tube end face 15 is defined by an end face of an inner tube layer 13 and an end face of an outer tube tip 14. The outer tip 14, sometimes referred to herein as the tube tip 14 or as tip 14, has a first end 30 and a second end 31, with said tube end face 15 being proximate to the first end 30. Between said first end 30 and said second end 31, tube tip 14 surrounds an inner layer 13 of the tube. In one embodiment, tube tip 14 is secured to a sleeve 12 of the tubing assembly by a retainer feature 16, which can be a feature or combination of features of a sleeve 12. Proximate to the second end 31 of said overmolded tube tip 14, a sleeve 12 surrounds the inner tubing layer 13. In one embodiment, sleeve 12 surrounds said inner tubing layer 13 between the second end 31 of said tube tip 14 and the first end 3 of said actuator nut 2. As shown in
The use of an internally threaded portion 22 on said housing body 21 is a matter of choice. Those skilled in the art will therefore appreciate that, in an alternative embodiment, the nut 2 could have an internally threaded portion (not shown) and the housing body 21 could have an externally threaded portion (not shown).
Although not shown in
It will be appreciated that the tubing layer 13 can comprise a number of different materials depending on the particular application, as that may involve a particular type of sample, a particular type of solvent, and/or a particular pressure range. For example, the outer layer 19 of tube can comprise a metal, such as stainless steel (such as 316 stainless steel) or titanium, or a reinforced polymeric material, including composite or braided materials, such as polymeric materials that are reinforced or braided with carbon, carbon fibers, steel fibers, or the like. In embodiments comprising a metallic outer layer 19, the metal temper can be varied to provide a balance between high pressure capability and tubing flexibility. The inner layer 13 can comprise a biocompatible polymer, such as polyetheretherketone (PEEK). Other polymer materials which may be used for the inner layer 13 include, but are not limited to, TEFLON®, TEFZEL®, DELRIN®, perfluoroalkoxy (PFA, also called perfluoroalkoxyethylene), fluorinated ethylene propylene (PEP), polytetrafluoroethylene (PETE), ETFE (a polymer of tetrafluoroethylene and ethylene), polyetherimide (PEI), polyphenylene sulfide (PPS), polypropylene, sulfone polymers, polyolefins, polyimides, other polyaryletherketones, other fluoropolymers, polyoxymethylene (POM), and others, depending on the foregoing factors or perhaps others. In addition, PEEK (or other polymers) may be used that is reinforced or braided with carbon, carbon fibers, steel fibers, or the like. Furthermore, in certain embodiments the inner layer 13 may be coated with a material to increase strength, improve chemical resistance, improve temperature stability, or reduce permeability. Such coatings include, but are not limited to, metallization, polymeric coating, silicon-based coatings, and carbon-based coatings. Additionally, in certain embodiments the inner layer may be heat treated to improve properties such as crystallinity, chemical resistance, or permeability. Those skilled in the art will appreciate that, although shown and described herein as a single layer, the inner layer 13 of the tube may actually comprise two or more layers if desired. The final tube may be treated to further improve the performance, including heat treatment or annealing to strengthen the polymer components, or pressurizing, with or without added heat, to allow the inner layer to conform to the outer layer. A mandrel can be used in the inner diameter of the inner layer to preserve the passageway.
Actuator nut 2, inner tubing layer 13, sleeve 12, and retainer feature 16 may be embodied in a variety of configurations. Turning now to
Referring now to
As shown in
In one embodiment, actuator nut 2 is comprised of a metal, such as, for example, stainless steel. Those skilled in the art will appreciate that the actuator nut 2 may be comprised of other materials such as titanium, fused silica, or a reinforced rigid polymer material (e.g., a carbon-fiber PEEK™ or other metal-braided polymer material). More rigid polymer materials may be more desirable in some applications, since stainless steel has some drawbacks in biological environments. For example, components in a biological fluid can attach to stainless steel, and stainless steel ions may leak into said fluid—both events having the potential to obscure measurements in liquid chromatography and other analytic chemistry applications.
Still referring to
Also shown in
The tube tip 14 can be overmolded onto an end portion of the inner tubing layer 13, the outer tubing layer 19, and sleeve 12. For example, and as shown in
Referring now to
Referring to
Referring now to
Those skilled in the art will appreciate that other configurations besides those illustrated and described in this disclosure can be used in various applications of the tubing and fitting assemblies in accordance with the present disclosure. It will also be appreciated that the materials described above which can be used for the various features and components of the fitting and tubing assemblies of the present disclosure can likewise be used for the same or similar features and components of the tubing assemblies illustrated in
A further embodiment is shown in
As further shown in
During use, the nut 71 is reversibly connected to the housing by threading the external threads into a housing and reversibly connecting a port to the opposite end of the housing, a face seal is established between the tip and the bottom of the port without the use of ferrules to grip the tubing. The fitting assembly nut 71 drives against the bearing surface of the transfer tubing 72 to push the sealing surface of the tip 73 into and against the port bottom. The tip seal to the liner tubing 75 is created by an interference fit created by the internal diameter of the tip being smaller than the outside diameter of the tubing that requires the liner tubing 75 to be drawn into the tip 73. The tip 73 can be slid into position against the reinforcement tubing 74. The transfer tubing 72 is slid over the outside of the tip 73 and crimped into place by means known to those skilled in the art including, for example, the presence of angled surfaces that interact to create a taper lock interference fit. In the embodiment described and shown in
A closer view of the fitting including the tubing and passageway is shown in
An alternate embodiment of the fitting of
An embodiment including an alternate tip 83 is shown in
An enlarged view of the embodiment of
Another embodiment of a connection assembly is shown in
Additional embodiments of the disclosed connection assemblies that can be used to form a face seal with various flat bottomed ports or fixtures as required and that do not include a liner tubing are shown in
An additional embodiment is shown in
As described for
Referring now to
In
The groove or slot 1050 of the nut 1001 provides an advantage because it allows an operator to route a tube (such as described above in various embodiments) through an analytical instrument system and/or its various components, then add the nut 1001 to make up a connection with the fitting assembly after the tube is roughly in place. In a number of applications, the space for the various components can be limited and fairly tight, and in such situations having the nut captivated on the tube assembly can make it difficult to route the assembly to the proper location to make up a connection. Because tubes periodically need to be replaced in AI systems, having the slot 1050 on the nut 1001 allows for easier location and for easier and faster replacement of tubing in many situations. This approach also makes it easier and more common for reuse of the nut 1001, since the nut 1001 need not be attached to the tubing. The groove 1050 also may allow for easier use of the nut 1001 when the nut 1001 is rotated in engagement with a port, such as a port in an LC, HPLC, UHPLC, or other AI system, or other component, such as in such a system (which could be a union, pump, column, filter, guard column, injection valve or other valve, detector, pressure regulator, reservoir, or another fitting, such as a tee, cross, adapter, splitter, sample loop, connector, or the like) to make a fluidic connection, such as when used in connection with the embodiments of this disclosure described above. Those skilled in the art will appreciate that, in an alternative embodiment, the nut 1001 could have an internally threaded portion (not shown) adapted to engage with an externally threaded portion of a port or other component such as those listed, or could be otherwise configured to provide axial loading.
The nut 1001 can be made of a metal, such as, for example, stainless steel. Those skilled in the art will appreciate that the nut 1001 may be comprised of other materials such as titanium, fused silica, or a reinforced rigid polymer material (e.g., a carbon-fiber PEEK™ or other metal-braided polymer material). More rigid polymer materials may be more desirable in some applications, since stainless steel has some drawbacks in biological environments. For example, components in a biological fluid can attach to stainless steel, and stainless steel ions may leak into said fluid—both events having the potential to obscure measurements in liquid chromatography and other analytic chemistry applications. The nut 1001 thus can comprise biocompatible materials, such as polyetheretherketone (PEEK), which are generally inert with respect to biological materials. Those skilled in the art will appreciate that the slot 1050 of the nut 1001 need not run the entire longitudinal length of the nut 1001. In addition, a plurality of slots can be provided instead of a single slot 1050. For example, the nut 1001 could have a top slot at the top end 1025 of the nut 1001 and also a bottom slot at the bottom end 1005 of the nut 1001.
Referring now to
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It will be appreciated that, as noted below, the tubing, and also the components of a fitting assembly or connection system, used in many analytical instrument systems for fluidic connections can be very small. Moreover, the components used in many analytical instrument systems can vary, and often need to be changed or replaced, such as replacing columns, pumps, injection valves, and so forth, whether when switching from one particular application of the system for one type of analysis to another or substantially re-organizing the system and its components. Given the small size of the tubing and fitting assembly or fluidic connection components, such as nuts, ferrules, sleeves, transfer tubing, tips, and so forth, especially together with the complexity of many analytical instrument systems, many operators often spend additional time and effort locating the tubing for a connection or locating an fitting assembly, sometimes in very awkward or difficult to reach locations. By providing a slot 1050 in the nut 1001, an operator can more easily install or disconnect a fluidic connection in an AI system. For example, to make a connection, an operator can first locate or insert the nut 1001 in a port, and then easily insert a portion of the tubing or tube assembly through the slot 1050 of the nut 1001, and then tighten the nut 1001 in the port to form a sealed connection. Similarly, an operator, when disconnecting a fluidic connection, can simply rotate the nut 1001 relative to the port to loosen the fitting assembly and, without removing the nut 1001 from the port, remove the tubing by pulling the tubing through the slot 1050.
Those skilled in the art will appreciate that the current disclosure provides a tubing assembly and a fitting assembly which can be used for making one or more connections in any system that utilizes a face seal (such as a flat-bottomed port), and can withstand the fluid pressures required for ultra-high pressure liquid chromatography (UHPLC) and other analytical instrument applications. While PEEK lined steel (PLS) tubing has been used in other applications, those skilled in the art will appreciate that the tubing and fitting assembly of the present disclosure overcomes issues with the use of PLS, such as, for example, difficulties encountered by users because of the inability of PLS to bend. Those skilled in the art will appreciate that the fitting and tubing assembly configurations described and shown in this disclosure focus on only one end of the tubing and fitting assembly, but the present disclosure may be used in embodiments as a complete fluidic connection between two components, for example, such as a connection including two nuts and tubing with two ends such as described and shown in this disclosure for providing a fluid connection between any two points in an analytical instrument system or other system.
Those skilled in the art will further appreciate that the tubing and fitting assemblies shown and disclosed herein will successfully handle fluid connections in systems in which small volumes of a fluid at high pressures are needed. For example, the tubing in accordance with the present disclosure may have an outside diameter (OD) in the range of from about 1/64 inches to about ¼ inch, or about 1/64, 1/32, 1/16, ⅛ or ¼ of an inch in diameter inclusive, and may have an inner diameter (ID) of from about 0.001 to about 0.085 inches, or about 0.001, 0.002, 0.006, 0.010, 0.015, 0.020, 0.025, 0.030, 0.060, or 0.085 inches, inclusive. Moreover, the assembly described and shown in this disclosure is capable of UHPLC pressures (>18,000 psi) at finger-tight torque values of 2-3 in*lbs, for example. The assemblies are also flexible and capable of multiple connection uses prior to failure. It is believed that the fitting assembly of the present disclosure is able to translate rotational torque directly to axial force to generate the seal with a flat-bottom port which will hold at very high pressures like those noted. Those skilled in the art will also appreciate that the fitting assembly of the present disclosure does not require any ferrules or other similar sealing mechanisms, is easy to use by an operator, and can generate a seal at high pressures with torque levels that do not require any tools and are easily obtained by most users. Using such a torque load to make a test connection with a fitting assembly in accordance with the present disclosure, we were able to obtain a sealed fluid connection that maintained a seal at fluid pressures higher than 25,000 psi before a burst or a leak.
While the present invention has been shown and described in various embodiments, those skilled in the art will appreciate from the drawings and the foregoing discussion that various changes, modifications, and variations may be made without departing from the spirit and scope of the invention as set forth in the claims. For example, the shapes, sizes, features, and materials of the fitting assembly, fluid connection, and/or analytical instrument systems of the present disclosure may be changed. Hence, the embodiments shown and described in the drawings and the above discussion are merely illustrative and do not limit the scope of the invention as defined in the claims herein. The embodiments and specific forms, materials, and the like are merely illustrative and do not limit the scope of the invention or the claims herein.
This application is a continuation and claims benefit of priority of U.S. patent application Ser. No. 14/922,041, filed on Oct. 23, 2015, which in turn claims benefit of priority from U.S. Provisional Patent Application No. 62/067,739, filed Oct. 23, 2014, U.S. Provisional Patent Application No. 62/127,276, filed Mar. 2, 2015, and U.S. Provisional Patent Application No. 62/168,491, filed May 29, 2015, each of which is hereby incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 62067739 | Oct 2014 | US | |
| 62127276 | Mar 2015 | US | |
| 62168491 | May 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14922041 | Oct 2015 | US |
| Child | 16856751 | US |
