Compression nut or fitting with removable plunger to facilitate removal of jammed ferrule

Abstract

The present invention relates to a compression fitting comprising a nut having a threaded end for receiving a threaded tube and a receiving end for receiving a plunger head, and a plunger having an internal bore for receiving a capillary tube and the plunger head for engaging a ferrule positioned within the receiving end between the plunger head and the threaded tube, the plunger being slidingly engaged with the nut to force the ferrule off the nut.

Description

Technical Field

[0001] This disclosure generally relates to the field of gas chromatography, including clamping nuts or fittings with removable plungers for easy removal of jammed collars. Background Technology

[0002] Gas chromatography (GC) is a useful technique for analyzing volatile compounds in samples. GC columns, with a retention medium or stationary phase, can be used to separate volatile compounds based on their affinity for the retention medium. The time required for a compound to pass through the column (retention time) depends on the compound because compounds with a higher affinity for the stationary phase can remain in the column for a longer period compared to compounds whose interaction with the stationary phase is limited.

[0003] Because the mobile phase is a gas (typically helium, hydrogen, or nitrogen), a hermetically tight connection must be ensured between the column and the sampling device (such as an injector) at one end and the detector at the other. Typically, connecting the column involves attaching a collar to the column, trimming the end of the column to remove any damage or contamination caused by the collar installation, and positioning the end of the column at the optimal length for the sampling device or detector. The collar can be compressed and deformed to form a hermetically tight seal. Summary of the Invention

[0004] In a first aspect, the compression fitting may include: a nut having a threaded end for receiving a threaded tube and a receiving end for receiving a plunger head; and a plunger having an inner bore for receiving the tube and a plunger head for engaging a collar, the collar being positioned within the receiving end between the plunger head and the threaded tube. The plunger may be slidably engaged with the nut to force the collar disengage from the nut.

[0005] In various embodiments of the first aspect, the compression fitting may further include a threaded tube.

[0006] In various embodiments of the first aspect, the plunger head may include a tapered collar engagement surface.

[0007] In various embodiments of the first aspect, the threaded end of the nut may be an internally threaded end for internally receiving a threaded tube.

[0008] In various embodiments of the first aspect, the plunger may have an inner bore for receiving the tube.

[0009] In various embodiments of the first aspect, the plunger may be removable from the nut.

[0010] In various embodiments of the first aspect, the plunger may include a retaining clip or device for securing at least a portion of the plunger within a nut.

[0011] In various embodiments of the first aspect, the nut may include a spring for biasing the plunger toward the proximal end of the nut.

[0012] In various embodiments of the first aspect, the nut may include an outer facet for engaging with a tool for tightening and loosening the nut.

[0013] In various embodiments of the first aspect, the nut may include a wing for tightening the nut with fingers.

[0014] In a second aspect, a method of operating a compression fitting may include: disengaging a nut from a threaded tube, the nut including a threaded end for threaded engagement of the threaded tube and a receiving end for receiving a plunger head, and a collar compressed between the plunger head and the threaded tube; and axially translating the plunger relative to the nut to remove the collar stuck in the nut or on the plunger head.

[0015] In various embodiments of the second aspect, the method may further include engaging a nut and a threaded tube. In a specific embodiment, engaging the nut and threaded tube may include deforming a collar within a receiving end between the plunger head and the threaded tube to form an airtight seal. In a specific embodiment, the method may further include inserting a capillary tube through the plunger, nut, collar, and threaded tube prior to engaging the nut and threaded tube. In a particular embodiment, engaging the nut and threaded tube includes tightening the nut with a tool.

[0016] In various embodiments of the second aspect, disengaging the nut and the threaded tube may include loosening the nut with a tool.

[0017] In various embodiments of the second aspect, the translational plunger may include removing the plunger from the nut.

[0018] In various embodiments of the second aspect, the translational plunger may include translating the plunger until the plunger head extends through the threaded end of the nut. In a specific embodiment, the translational plunger may include translating the plunger until a retaining clamp or device restricts further movement of the plunger.

[0019] In various embodiments of the second aspect, the method may further include biasing the plunger toward the threaded end of the nut with a spring, the nut further including a spring-loaded portion in which the spring is positioned. Attached Figure Description

[0020] To gain a more comprehensive understanding of the principles and advantages disclosed herein, the following description is provided in conjunction with the accompanying drawings, in which:

[0021] Figure 1 This is a diagram of an exemplary gas chromatography system.

[0022] Figure 2A This is a cross-sectional view of an exemplary post connector according to various embodiments.

[0023] Figure 2B This is a perspective view of an exemplary post connector according to various embodiments.

[0024] Figure 2C This is a cross-sectional view of an exemplary post connector according to various embodiments.

[0025] Figure 3A This is a cross-sectional view of an exemplary post connector with posts according to various embodiments.

[0026] Figure 3B This is a perspective view of an exemplary post connector according to various embodiments.

[0027] Figure 3C This is a cross-sectional view of an exemplary post connector according to various embodiments.

[0028] Figure 4 This is a flowchart illustrating a method of using a post connector according to various embodiments.

[0029] It should be understood that the drawings are not necessarily drawn to scale, nor are the relationships between objects in the drawings necessarily drawn to scale. The drawings are intended to provide clear and easy-to-understand depictions of the various embodiments of the devices, systems, and methods disclosed herein. Where appropriate, the same reference numerals will be used throughout the drawings to refer to the same or similar parts. Furthermore, it should be understood that the drawings are not intended to limit the scope of this teaching in any way. Detailed Implementation

[0030] An embodiment of a compression nut or fitting having a removable plunger for easy removal of a stuck collar.

[0031] The chapter titles used in this article are for organizational purposes only and should not be construed as limiting the topics described in any way.

[0032] In this detailed description of various embodiments, numerous specific details are set forth for illustrative purposes to provide a thorough understanding of the disclosed embodiments. However, those skilled in the art will appreciate that these various embodiments may be practiced with or without these specific details. In other instances, structures and apparatus are shown in block diagram form. Furthermore, those skilled in the art will readily understand that the particular order in which the methods are presented and performed is illustrative and that the order may be altered while still remaining within the spirit and scope of the various embodiments disclosed herein.

[0033] All documents and similar materials cited in this application, including but not limited to patents, patent applications, papers, books, monographs, and Internet web pages, are expressly incorporated herein by reference in their entirety for any purpose. Unless otherwise described, all technical and scientific terms used herein have the meanings commonly understood by one of ordinary skill in the art to which the various embodiments described herein pertain.

[0034] It should be understood that the terms "about" are implicitly used before terms such as temperature, concentration, time, pressure, flow rate, and cross-sectional area discussed in the teachings of this invention, resulting in slight and non-material deviations within the scope of the teachings. In this application, unless otherwise specifically stated, the use of the singular includes the plural. Furthermore, the use of "comprise," "contain," and "include" is not intended to be restrictive. It should be understood that the foregoing general description and the following detailed description are merely exemplary and illustrative, and do not limit the teachings of this invention.

[0035] As used herein, “a / an” can also mean “at least one” or “one or more”. Furthermore, the use of “or” is inclusive, such that the phrase “A or B” is true when “A” is true, “B” is true, or both “A” and “B” are true. Additionally, unless the context otherwise requires, singular terms should include plural terms and plural terms should include singular terms.

[0036] A “system” describes a set of real or abstract components that comprise a whole, wherein each component interacts with or is related to at least one other component within the whole.

[0037] Figure 1 A typical gas chromatography system 100 is described. The system includes an injector 102, a column 104, and a detector 106. A sample 108 can be supplied to the injector 102. In various embodiments, the sample 108 can be a gaseous sample, such as for headspace analysis. In other embodiments, the sample 108 can be a liquid sample, and the injector can vaporize the liquid sample into a gaseous state. The sample can be moved from the injector to the column 104 by a carrier gas. The column 104 includes a retention medium, typically as a thin coating on the inner surface of the column 104. The retention medium can retain some compounds from the vaporized sample in different ways, such that the amount of time required to pass through the column is related to the compounds. In this way, compounds in the vaporized sample can be separated based on the time spent passing through the column (retention time).

[0038] After exiting column 104, the compound can enter detector 106. Various detectors can be used as part of the GC system, including flame ionization detectors, nitrogen-phosphorus detectors, electron capture detectors, thermal conductivity detectors, flame photometric detectors, mass spectrometers, etc.

[0039] Injector 102 can be coupled to post 104 via connector 110, and post 104 can be coupled to detector 106 via connector 112. In various embodiments, connectors 110 and 112 can be compression fittings, wherein a ferrule is mounted onto post 104 and deformed to form a seal, thereby preventing leakage.

[0040] When a ferrule is compressed, it may sometimes become stuck on the compressed portion, or it may expand into part of the compression nut / fitting and become difficult to remove. It can be difficult to remove a ferrule stuck in a compression nut for reuse or to disassemble the mating part. In some prior art, a groove is made in the nut, and the stuck ferrule can be pried out using a wire or other pliers. In other prior art, a hole is made in the nut or compression fitting, allowing access to pry out the stuck ferrule.

[0041] In various embodiments, the nut to be used in the compression fitting may include a removable plunger that can be pushed out of the nut / fitting along with a stuck collar to facilitate ejection or removal of the collar stuck on the sealing surface or inside the nut. In some embodiments, a spring and backstop may be designed to eject the stuck / lodged collar from a cylindrical guide. In other embodiments, there is no spring, or the spring does not assist in ejecting the collar. The plunger pushes the collar from the nut to an area where it can be stuck.

[0042] Figure 2A , Figure 2B and Figure 2C Exemplary compression fitting 200 is described. The compression fitting may include a compression nut 202 having a removable plunger 204.

[0043] The compression nut 202 may include a threaded portion 206 at a proximal end 208 and a receiving portion 210 at a distal end 212. The outer surface 214 of the threaded portion 206 may have facets for engaging with a tool such as a wrench or pliers to tighten / loosen the compression nut 202.

[0044] The plunger 204 may include a plunger head 216, a plunger shaft 218, and a hollow bore 220 extending along the length of the plunger 204. The plunger head 216 may include a collar engagement surface 222. In various embodiments, the collar engagement surface 222 may be tapered to receive the tapered end of a collar. In other embodiments, the collar engagement surface 222 may be flat. Typically, the collar engagement surface 222 may be complementary in shape to the collar 226. The plunger head 216 may be sized to fit within a receiving portion 210 of the nut 202 with minimal lateral movement but ample axial sliding capability. The size and shape of the bore 220 may be designed to receive a capillary, such as a gas chromatography column or transfer line.

[0045] In various embodiments, when fully assembled, such as Figure 2C As shown, capillary tube 224 can be inserted through plunger 204, nut 202, collar 226, and threaded tube 228. The threaded tube may include a collar engagement surface 230. The collar engagement surface 230 of the threaded tube 228 may have various shapes, such as a flat surface as shown or a tapered shape similar to the collar engagement surface 222 of plunger 204. Other shapes may complement the shape of collar 226.

[0046] The collar 226 can be positioned within the receiving portion 210 of the nut 202, and the threaded tube 228 can be threadedly engaged with the threaded portion 206 of the nut 202. Tightening the nut 202 against the threaded tube 228 compresses the collar 226 between the collar engagement surface 230 of the threaded tube 228 and the collar engagement surface 222 of the plunger 204. In various embodiments, the compression of the collar 226 can deform the collar 226 to form an airtight bond between the collar 226 and the capillary tube 224 and between the collar 226 and the collar engagement surface 230 of the threaded tube 228. Additionally, the collar can form tight contact with the inner surface 232 of the receiving portion 210 of the nut 202 and the collar engagement surface 222 of the plunger 204.

[0047] In various embodiments, when the nut 202 is disengaged from the threaded tube 228, the collar 226 may remain engaged on one or more surfaces. For example, the collar may be engaged inside the nut 202. The plunger 204 may be pushed toward the proximal end 208 of the nut 202 to remove the collar 226. In another embodiment, the collar 226 may be engaged on the collar engagement surface 222 of the plunger 204, which may again be disengaged from the nut 202 proximal end 208 along with the collar 226, thereby allowing access to the collar 226 to remove it from the collar engagement surface 222 of the plunger 204.

[0048] In various embodiments, the plunger 204 can be removed from the nut 202 by pushing the plunger 204 through the proximal end 208 of the nut 202. In other embodiments, at least a portion of the plunger 204 can be held within the nut 202 by using a retaining clip. The retaining clip prevents the plunger 204 from being completely pulled out of the nut. The retaining clip can be positioned such that at least a portion of the plunger head 216 extends beyond the proximal end 208 of the nut 202.

[0049] Figure 3A and Figure 3B An alternative embodiment of a compression fitting 300 having a spring-loaded nut 302 and a plunger 304 is described.

[0050] The spring-loaded nut 302 may include a threaded portion 306 at a proximal end 308 and a receiving portion 310. The compression nut may further include a spring-loaded portion 312 that houses a spring 314. Additionally, the spring-loaded portion 312 may include a wing 316. The wing 316 provides a surface for finger engagement while simultaneously tightening the spring-loaded nut 302.

[0051] The plunger 304 may include a plunger head 318, a plunger shaft 320, and a hollow bore 322 extending along the length of the plunger 304. The plunger head 318 may include a collar engagement surface 324. In various embodiments, the collar engagement surface 324 may be tapered to receive the tapered end of a collar. In other embodiments, the collar engagement surface 324 may be flat to receive the flat end of a collar. Typically, the shape of the collar engagement surface 324 may be complementary to the shape of the collar. The plunger head 318 may be sized to fit within a receiving portion 310 of the nut 302 with minimal lateral movement but easy axial sliding. The size and shape of the bore 322 may be designed to receive a capillary, such as a gas chromatography column or transfer line.

[0052] In various embodiments, when fully assembled, such as Figure 3C As shown, capillary tube 326 can be inserted through plunger 304, nut 302, collar 328, and threaded tube 330. Threaded tube 330 may include collar engagement surface 332 to press against collar 328. Typically, the shape of collar engagement surface 332 may be complementary to collar 328, such as being flat as shown or tapered similar to collar engagement surface 324 of plunger head 318.

[0053] The collar 328 can be positioned within the receiving portion 310 of the nut 302, and the threaded tube 330 can be threadedly engaged with the threaded portion 306 of the nut 302. Tightening the nut 302 against the threaded tube 330 compresses the collar 328 between the collar engagement surface 332 of the threaded tube 330 and the collar engagement surface 324 of the plunger 304.

[0054] In various embodiments, when the nut 302 is disengaged from the threaded tube 330, the collar 328 may remain engaged on one or more surfaces. For example, the collar may be engaged inside the nut 302. The plunger 304 may be pushed toward the proximal end 308 of the nut 302 to remove the collar 328. In another embodiment, the collar 328 may be engaged on the collar engagement surface 324 of the plunger 304. The plunger 304 may be axially translated relative to the nut 302, at least until the plunger head 318, together with the collar 328, leaves the proximal end 308 of the nut 302, thereby allowing access to the collar 328 to remove it from the collar engagement surface 324 of the plunger 304.

[0055] In various embodiments, the plunger 304 can move against the check valve 334 and the spring 314. When the nut is removed, the spring 314 can push the plunger 304 toward the collar 328 and help eject the used collar 328.

[0056] In various embodiments, the retaining clip 336 prevents the plunger 304 from being completely withdrawn from the nut. In various embodiments, the retaining clip 336 may be positioned such that at least a portion of the plunger head 318 extends beyond the proximal end 308 of the nut 302. In other embodiments, the plunger 304 may be detachable from the nut 302 without the retaining clip or device.

[0057] In various embodiments, the spring load portion 312 may further include a spring travel limiting retainer 340 and a retaining clip 342. The spring travel limiting retainer 340 limits the compression of the spring 314, thereby ensuring that the collar 328 is compressed between the collar engagement surface 324 of the plunger 302 and the collar engagement surface 332 of the threaded tube 330. The spring 314 may then bias the check valve 334 and the plunger 304 toward the threaded tube 330 to provide pressure on the collar 328, thereby maintaining a seal as the collar 328 continues to deform at high temperatures.

[0058] Figure 4 The method of using compression fittings, such as compression fitting 200 or compression fitting 300, is demonstrated. At 402, a tube is inserted through a nut and a plunger, a collar, and a threaded tube. In various embodiments, the tube may be a capillary column with a stationary phase coated on at least a portion of the inner surface of the capillary column. In other embodiments, the tube may be a transmission line or other tube without a stationary phase. In yet another embodiment, the tube may be a filled capillary column that can be filled with stationary phase particles. In yet another embodiment, various other types of tubes may be used.

[0059] At position 404, a nut and a threaded tube can be engaged. In various embodiments, the nut can be tightened with fingers. In other embodiments, a tool can be used to tighten the nut. The coupling nut and threaded tube can compress and deform the collar, thereby forming an airtight seal to prevent leakage.

[0060] At position 406, the sample can be analyzed, for example, by separation in a gas chromatography system. In various embodiments, the components of the separated sample can be detected and identified, for example, by using a mass spectrometer.

[0061] At 408, the nut and threaded tube can be disengaged, and at 410, the capillary can be detached from the compression coupler. In various embodiments, the capillary column may need to be replaced or trimmed. In other embodiments, the capillary may become clogged or broken and require replacement. In yet another embodiment, the positioning of the capillary may need to be adjusted.

[0062] At position 412, a plunger can be used to remove the stuck collar. In various embodiments, the collar may be stuck on the nut, and axial translation of the plunger relative to the nut can be used to force the collar out of the nut. In other embodiments, the collar may be stuck at one end of the plunger, and translating the plunger until at least a portion of the plunger head is away from the nut allows access to remove the collar from the plunger head.

[0063] At 414, the new collar can be replaced, and returning to 402, the compression coupler can be reassembled.

[0064] While the teachings of the invention have been described in conjunction with various embodiments, the teachings are not intended to be limited to such embodiments. Rather, the teachings encompass various alternatives, modifications, and equivalents, as will be appreciated by those skilled in the art.

[0065] Furthermore, in describing various embodiments, this specification may present methods and / or processes as steps in a specific order. However, methods or processes should not be limited to the specific order of steps described herein, to the extent that they do not depend on such a specific order. As will be appreciated by those skilled in the art, other orders of steps may be possible. Therefore, the specific order of steps set forth in this specification should not be construed as a limitation of the claims. Additionally, the claims for methods and / or processes should not be limited to performing the steps in the order they are written, and it will be readily understood by those skilled in the art that the order may vary while still remaining within the spirit and scope of the various embodiments.

Claims

1. A compression fitting comprising: A nut having a threaded end for receiving a threaded tube and a receiving end for receiving a plunger head; and A plunger having an inner bore for receiving a capillary tube and a plunger head for engaging a collar, the collar being positioned within the receiving end between the plunger head and the threaded tube, the plunger being slidably engaged with the nut and capable of translation until the plunger head extends through the threaded end of the nut to force the collar disengage from the nut. in, The plunger pushes the collar to remove it from the threaded end of the nut, and The nut includes a spring for biasing the plunger toward the proximal end of the nut.

2. The compression fitting according to claim 1, further comprising the threaded tube.

3. The compression fitting according to claim 1, wherein the plunger head includes a tapered collar engagement surface.

4. The compression fitting according to claim 1, wherein the threaded end of the nut is an internal threaded end for internally receiving the threaded tube.

5. The compression fitting according to claim 1, wherein the plunger has an inner bore for receiving a capillary.

6. The compression fitting according to claim 1, wherein the plunger is detachable from the nut.

7. The compression fitting of claim 1, wherein the plunger includes a retaining clip or device for retaining at least a portion of the plunger within the nut.

8. The compression fitting of claim 1, wherein the nut includes an outer facet for engaging with a tool for tightening and loosening the nut.

9. The compression fitting of claim 1, wherein the nut includes a wing for tightening the nut with fingers.

10. A method of operating a compression fitting, comprising: Disconnect the nut from the threaded tube, the nut including a threaded end for threaded engagement of the threaded tube and a receiving end for receiving a plunger head, as well as a collar compressed between the plunger head and the threaded tube. The plunger is axially translated relative to the nut until the plunger head extends through the threaded end of the nut to remove the collar stuck in the nut or on the plunger head; as well as A spring biases the plunger toward the threaded end of the nut, the nut further including a spring-loaded portion, the spring being positioned within the spring-loaded portion. The plunger pushes the collar to remove it from the threaded end of the nut.

11. The method of claim 10, further comprising engaging the nut and the threaded tube.

12. The method of claim 11, wherein engaging the nut and the threaded tube comprises deforming the collar within the receiving end between the plunger head and the threaded tube to form an airtight seal.

13. The method of claim 11, further comprising inserting a capillary tube through the plunger, nut, collar, and threaded tube before engaging the nut and the threaded tube.

14. The method of claim 11, wherein engaging the nut and the threaded tube comprises tightening the nut with a tool.

15. The method of claim 10, wherein disengaging the nut and the threaded tube comprises loosening the nut with a tool.

16. The method of claim 10, wherein translating the plunger includes removing the plunger from the nut.

17. The method of claim 10, wherein translating the plunger comprises translating the plunger until the plunger head extends through the threaded end of the nut.

18. The method of claim 17, wherein translating the plunger includes translating the plunger until a retaining clamp or device restricts further movement of the plunger.

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