Dynamic axial compression of preparative columns using external compression
By using a dynamic axial compression column structure to dynamically adjust the relative positions of the endplate assemblies, the problem of uneven particle bed after column packing is solved, thus improving the efficiency and performance of the column.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BIO RAD LABORATORIES INC
- Filing Date
- 2022-03-15
- Publication Date
- 2026-07-03
AI Technical Summary
Existing chromatographic columns have difficulty maintaining the uniformity and stability of the particle bed after packing, resulting in uneven flow of the mobile phase and affecting column efficiency and performance.
A dynamic axial compression column structure is adopted. By setting movable end plate assemblies and external compression devices at both ends of the column, the relative position of the end plate assemblies is maintained by components such as rods and springs, and the cavity space is dynamically adjusted to eliminate or reduce the formation of cavities and end spaces.
It effectively maintains the uniformity and stability of the chromatographic bed, improves the efficiency and performance of the column, prevents uneven flow of the mobile phase within the column, and reduces the generation of non-ideal peaks.
Smart Images
Figure CN117015429B_ABST
Abstract
Description
[0001] Cross-referencing related applications
[0002] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 181,133, filed April 28, 2021, and U.S. Provisional Patent Application No. 63 / 161,823, filed March 16, 2021, the entire contents of each of which are hereby incorporated herein by reference for all purposes. Background Technology
[0003] Chromatography is a technique used to separate mixtures. The mixture is dissolved in a fluid (gas or liquid, such as water) called the mobile phase. The fluid carries the mixture through a feature containing a material called the stationary phase. Different molecules within the mixture reside on or in the stationary phase for different periods of time, which allows them to be separated.
[0004] The stationary phase can be a medium loaded and / or packed within the column. Column efficiency is a critical parameter in chromatographic separation. The stationary phase in the column is typically a solid product in the form of fine particles. These fine particles are tightly packed into the column to form a chromatographic bed. The column itself is usually a hollow tube with end plates fixed at both ends to accommodate the packed particles. The bottom plate is typically fixed inside the column, while the top plate can move upwards or downwards to allow for packing beds of varying heights.
[0005] To achieve high efficiency, the particle arrangement within the column must be as uniform as possible. Furthermore, the space between the underside of the top plate and the top surface of the packed bed should be minimal or nonexistent. For incompressible particles such as silica, hydroxyapatite, and glass, maintaining uniformity and contact between the top plate and the bed surface can be difficult due to sedimentation after packing. Such sedimentation can occur, for example, during transport or while the mobile phase is flowing through the column. Therefore, improvements to the chromatographic column are highly beneficial. Summary of the Invention
[0006] One aspect of this disclosure relates to a dynamic axial compression column. The dynamic axial compression column includes a tube defining a first opening, a second opening, and a lumen extending from the first opening through the tube to the second opening. The dynamic axial compression column includes: a first endplate assembly sealing the first opening and extending movably at least partially into the lumen via the first opening; a second endplate assembly sealing the second opening; a plurality of rods, each extending along the outer side of the tube and connecting the first endplate assembly and the second endplate assembly; and a first plurality of compression devices located outside the tube. In some embodiments, each of the first plurality of compression devices engages one of the plurality of rods and biases the first endplate assembly toward the second endplate assembly.
[0007] In some embodiments, the dynamic axial compression column further comprises a medium filling the lumen. In some embodiments, the medium is compressible. In some embodiments, the medium is incompressible. In some embodiments, the medium may be at least one of silica, alumina, zirconium oxide, glass, hydroxyapatite, and fluorapatite.
[0008] In some embodiments, a first plurality of compression devices may apply a first pressure to the medium filling the cavity. In some embodiments, the first pressure is less than the maximum pressure applied to the medium without damaging it.
[0009] In some embodiments, the plurality of rods are at least two rods. In some embodiments, each of the first plurality of compression devices may be a spring. In some embodiments, the spring may be a disc spring. In some embodiments, the disc spring may be a plurality of stacked discs. In some embodiments, at least two of the plurality of stacked discs have opposite orientations.
[0010] In some embodiments, the dynamic axial compression column further includes a balancing plate positioned between the first plurality of compression devices and the first end plate assembly. In some embodiments, the balancing plate can transmit forces from the first plurality of compression devices equally to the first end plate assembly.
[0011] In some embodiments, the second endplate assembly extends at least partially into the lumen via a second opening. In some embodiments, the dynamic axial compression column further includes a second plurality of compression devices. In some embodiments, each of the second plurality of compression devices is external to the tube. In some embodiments, each of the second plurality of compression devices engages one of a plurality of rods and biases the second endplate assembly toward the first endplate assembly.
[0012] In some embodiments, the first plurality of compression devices may apply a first pressure to bias the first endplate assembly toward the second endplate assembly. In some embodiments, the first pressure is equal to or greater than the back pressure in the column, thereby eliminating the generation of headspace.
[0013] In some embodiments, the tube is circular. In some embodiments, the tube has a diameter of at least three centimeters. In some embodiments, the first endplate assembly includes a first inward face. In some embodiments, the second endplate assembly includes a second inward face. In some embodiments, each of the first and second inward faces is covered with glass frit. Attached Figure Description
[0014] Figure 1 A perspective view of a portion of a chromatographic column.
[0015] Figure 2 This is a perspective view of another part of the chromatographic column.
[0016] Figure 3 This is an example of a dynamic axial compression column.
[0017] Figure 4 This is a perspective view of one embodiment of a disc spring.
[0018] Figure 5 A side view of one embodiment of a stack of discs forming a disc spring.
[0019] Figure 6 This is a view of an embodiment of a chromatographic column including an equalization plate.
[0020] Figure 7 This is a view of another embodiment of the chromatographic column.
[0021] Figure 8 This is a schematic diagram showing the movement of the first end plate of the chromatographic column relative to the second end plate. Detailed Implementation
[0022] The efficiency and / or effectiveness of a chromatographic column depends at least in part on the uniformity of the packing of the chromatographic bed. Specifically, the formation of voids or channels within the chromatographic bed reduces column efficiency and effectiveness.
[0023] High efficiency requires that the particles inside the packed bed of the column be as uniform and stable as possible. However, maintaining such uniformity and stability can be difficult because the chromatographic bed settles after packing. This settling can occur due to movement or impact of the column, for example, during transport, storage, or installation, or due to the flow of the mobile phase through the column. Additional settling can create voids at the top of the column, which reduces the efficiency of the bed.
[0024] Figure 1 and 2 This is a partial view of column 100. A cavity 102 is formed in the packed bed 104, and there is liquid-filled space between the packed bed and the endplate assembly. In these figures, the column is operated by injecting fluid at the bottom and discharging it at the top. The continued settling of the resin after packing will thus allow the entire bed to be pushed upwards during flow, creating voids at the bottom of the column bed. If the flow direction is downwards, then voids will form at the top of the column bed.
[0025] The presence of cavity 102 and end space in column 100 can cause the mobile phase to move through column 100 in a non-uniform manner. The portion of mobile phase that travels through the cavity and end space travels a vertical distance faster than the portion that travels a longer path through the chromatographic bed. Those skilled in the art will recognize that this dissimilar flow of the mobile phase can produce multiple and / or non-ideal peaks, resulting in degraded column performance.
[0026] Embodiments of this disclosure relate to a dynamic axial compression column that can eliminate and / or minimize the formation of cavities and end spaces within the column bed, regardless of the flow direction.
[0027] Specifically, the dynamic axial compression column includes a tube defining a lumen. This tube has a first (top) end assembly and a second (bottom) end assembly, which, when inserted into the tube, restrict the lumen and define a lumen space within the tube. The tube extends between a first opening in the first (top) end assembly and a second opening in the second (bottom) end assembly. The first (top) end assembly is movable relative to the second (bottom) end assembly and the tube, such that the distance between the first (top) end assembly and the second (bottom) end assembly can be varied. In some embodiments, pressure on the first (top) end plate can move the first (top) end assembly toward the second (bottom) end assembly, thereby reducing the distance between the first (top) end assembly and the second (bottom) end assembly. This reduction in distance can reduce the volume of the lumen space.
[0028] In this document, the terms "first" and "top" are used interchangeably when referring to the end assembly or its portion. Similarly, the terms "second" and "bottom" are used interchangeably. The terms are descriptive only and do not necessarily refer to the relative height of the end assembly or its portion above the ground during use. That is, if the column were inverted, the portion described as "top" in this document would be considered "bottom" by the observer. vice versa .
[0029] In some embodiments, the first end assembly can be biased toward the second end assembly via a compression device. Due to this bias, in the event of any settling of the medium within the column, both the first and second end assemblies can move closer together, thereby preventing the formation of cavities. This compression device is located outside the lumen.
[0030] refer to Figure 3 An embodiment of a column 300 is shown, which may be a chromatographic column 300, also referred to herein as a dynamic axial compression column 300. The column 300 includes a tube 302 having a first end 346 and a second end 348 and defining a lumen 304. The tube 302 may include various shapes and sizes and may be made of various materials. In some embodiments, the tube 302 may be circular. The tube 302 may be made of any desired material, including one or more metals, alloys, polymers, composite materials, glass, etc. In some embodiments, the material may be selected to handle a desired range of pressures and mobile phases passing through the tube 302.
[0031] like Figure 3As seen herein, the column 300 may include a first end assembly 306 and a second end assembly 308, the first end assembly also referred to herein as a first end plate assembly 306, a top end assembly 306, a top end plate assembly 306, or a first head 306, and the second end assembly also referred to herein as a second end plate assembly 308, a bottom end assembly 308, a bottom end plate assembly 308, or a second head 308. In some embodiments, each end assembly 306, 308 may include an end plate 310 outside the tube 302, an insert 312, and an optional glass frit 320 that can contact the lower surface of the insert 312. The end assemblies 306, 308 also include a sealing mechanism 314, such as an O-ring, a gasket, an inflatable bladder, etc., which prevents material from escaping from the lumen during operation of the column.
[0032] In some embodiments, the end plate 310 and the insert 312 are a single piece. In some embodiments, the end plate 310 and the insert 312 are two different pieces joined together.
[0033] Each of the first and second end assemblies may include a variety of shapes and sizes and may be made of a variety of materials. In some embodiments, one or more component portions of the end assemblies may be made of one or more metals, alloys, polymers, composite materials, combinations thereof, etc. In some embodiments, the material may be selected to handle a desired range of pressure and flow phase through pipe 302.
[0034] refer to Figure 3 In the case of the lower end assembly, in one embodiment, the end plate may directly contact the lower end of the tube 302. In the case of the upper assembly, in one embodiment, a gap 318 may optionally exist between the bottom surface of the end plate 310 and the top surface of the tube 302.
[0035] In some embodiments, the top end assembly may be movable relative to the tube 302, while the sealing mechanism 314 may continue to seal the top opening 350 of the tube 302, also referred to herein as the first opening 350. The top opening 350 may be located in a first end 346 of the tube 302. In some embodiments, for example, the top end assembly may be movable relative to the tube 302 such that distance 318 decreases and distance 316 increases. Specifically, in some embodiments, the movement of the top end assembly 306 toward the bottom end assembly 308 will reduce the volume of the lumen space and eliminate any cavities or end spaces that may form when the medium within the lumen settles or is further compressed.
[0036] In some embodiments, the bottom end assembly 308 is movable relative to the top end assembly 306 and / or relative to the tube 302 via features similar to those of the top end assembly 306. In some embodiments, the bottom end assembly 308 may be fixed relative to the tube 302. In some embodiments, the bottom end assembly 308 may seal a bottom opening 352 of the tube 302, which is also referred to herein as a second opening 352. The bottom opening 352 may be located in a second end 348 of the tube 302.
[0037] Each of the first head 306 and the second head 308 may include an inwardly facing surface 313. Thus, the first head 306 may have a first inwardly facing surface 313, and the second head 308 may have a second inwardly facing surface 313. In some embodiments, the inwardly facing surfaces 313 of the heads 306, 308 are the portions of the insert that extend furthest into the lumen 304 of the tube 302. In some embodiments, and as... Figure 3 As shown, each of the inward-facing surfaces 313 of the first head 306 and the second head 308 is covered by glass frit 320. Glass frit 320 may include porous components that allow the flowing phase to pass through while preventing the stationary phase from passing through. Glass frit 320 may include, for example, mesh, sieve, sintered glass, sintered plastic, sintered ceramic, or metal.
[0038] The top end assembly 306 and the bottom end assembly 308 may be coupled and / or connected via a plurality of rods 322. The rods 322 may include various shapes and sizes and may be made of various materials. In some embodiments, such as Figure 3 As depicted, each of the rods 322 extends along the outer side of the tube 302 and connects the top end assembly 306 and the bottom end assembly 308, and specifically connects the end plate 310 of the top end assembly 306 to the end plate 310 of the bottom end assembly 308. In some embodiments, each of the rods 322 extends through a hole in the end plate 310 of the first head assembly 306 to allow the top end plate assembly 306 to move relative to the rod 322. In some embodiments, each of the rods 322 extends through a hole in the end plate 310 of the bottom end assembly 308 to allow the bottom end plate 310 to move relative to the rod 322.
[0039] In some embodiments, the plurality of rods 322 may include any desired number of rods 322. In some embodiments, the plurality of rods 322 may include, for example, at least two rods 322, at least three rods 322, at least four rods 322, etc. In some embodiments, the number of rods may increase as the width or diameter of the tube 302 increases.
[0040] Each of the rods 322 may include a first end 324 and a second end 326. In some embodiments, each of the first end 324 and the second end 326 may include a stop feature 328. The stop feature 328 may be configured to engage with one of the end plate assemblies 306, 308, and more specifically with one of the end plates 310 of the end plate assemblies 306, 308 to prevent the end plate assemblies 306, 308, and more specifically, to prevent the end plate 310 from moving beyond the stop feature 328. In some embodiments, the stop feature 328 may include a nut, a flange, a snap ring, a cotter pin, etc. In some embodiments, for example, where the bottom end assembly 308 does not move relative to the rod 322, the stop feature 328 may include a physical connection, such as welding, between the rod 322 and the bottom end assembly 308, and more specifically, with the end plate 310 of the bottom end assembly. In some embodiments, the stop feature 328 may include a nut, and each of the first end 324 and the second end 326 of the rod 322 may be threaded to be screwed onto the nut and thereby engage the nut.
[0041] In some embodiments, and such as Figure 3 As depicted, the chromatographic column 300 may include a plurality of compression devices 330. Each of these compression devices may be external to the tube 302, and each of these compression devices 330 may engage with one of the rods 322 and one of the end plate assemblies 306, 308, thereby allowing the end assemblies 306, 308 to move toward each other. Figure 3 In the embodiments depicted, each of the rods 322 has a compression device 330 that engages with the rod 322, specifically via a stop feature 328, and with a top endplate assembly 306, specifically with a base 310 of the top endplate assembly 306. The compression device 330 can generate a first force and apply it to other components of the chromatographic column 300 to bias the first endplate assembly 306 toward a second endplate assembly 308.
[0042] Each of the compression devices 330 may include a component configured to generate a biasing force. In some embodiments, each of the compression devices 330 may include a spring, such as a coil spring, a disc spring, a wave spring, etc. In some embodiments where the spring includes a disc spring, the disc spring may include, for example, a... Figure 4 The plurality of disks 400 shown can be arranged to form a shape as follows: Figure 5The stack 500 is shown. In some embodiments, one or more of the compression devices 330 may include a pneumatic cylinder, a hydraulic cylinder, a polymer compression device, a metal spring, a polymer spring, etc. Therefore, in some embodiments, each of the compression devices 330 may include a plurality of stacked disks 400. In some embodiments, the stack 500 may include a parallel stack, a series stack, or a parallel-series stack. In a parallel stack, all disks 400 in the stack 500 have the same orientation. In a series stack or a parallel-series stack, some disks 400, or in other words, at least two disks 400, in the stack 500 have opposite orientations.
[0043] In some embodiments where the first end plate assembly 306 moves relative to the tube 302, the compression device 330 may include a first set of compression devices 330. For example... Figure 7 The embodiment shown illustrates a view of another embodiment of a chromatographic column 700, also referred to herein as column 700 or dynamic axial compression column, in which each of the first endplate assembly 306 and the second endplate assembly 308 is movable relative to tube 302, and compression device 330 may include a first set of compression devices 330-A, also referred herein as a first plurality of compression devices 330-A, and a second set of compression devices 330-B, also referred herein as a second plurality of compression devices 330-B. In some embodiments, the first set of compression devices 330-A may engage with rod 322 and the first endplate assembly 306, and the second set of compression devices 330-B may engage with rod 322 and the second endplate assembly 308. In some embodiments, each of the first set of compression devices 330-A and the second set of compression devices 330-B may be outside the lumen 304 and the tube 302. Each of the first set of compression devices 330-A may engage one of the rods 322 and bias the first end plate assembly 306 toward the second end plate assembly 308, and each of the second set of compression devices 330-B may engage one of the rods 322 and bias the second end plate assembly 308 toward the first end plate assembly 306. In some embodiments, this may include the first set of compression devices 330-A applying a first force and / or pressure to bias the first end plate assembly 306 toward the second end plate assembly 308. In some embodiments, and as Figure 6 As shown, the fluid flowing within the chromatographic column 700 can exert pressure on all surfaces of the column 700. This pressure is called back pressure. If the back pressure exceeds the pressure generated by the compression device 330, then headspace can be created within the chromatographic column 700.
[0044] In some embodiments, the first pressure applied by the first set of compression devices 330-A is equal to or greater than the back pressure in the chromatographic column 700 to eliminate the generation of headspace. In some embodiments, the first pressure is less than the maximum pressure applied to the medium without damaging, destroying, or fracturing the medium.
[0045] In some embodiments, a plurality of compression devices 330 are configured to apply force and / or pressure together to bias the first endplate assembly 306 toward the second endplate assembly 308. In some embodiments, a plurality of compression devices 330 are configured to apply force and / or pressure together to a medium contained within a lumen 304.
[0046] In some embodiments where the stop feature 328 includes a nut, the stop feature 328 can be adjusted to change the compression of the compression device 330. In some embodiments, this change in the compression of the compression device 330 can change the force applied by the compression device 330 to bias the first end plate assembly 306 toward the second end plate assembly 308. In some embodiments, adjusting the stop feature 328 may include, for example, tightening or loosening the nut including the stop feature 328. In some embodiments, for example, the nut including the stop feature 328 may be tightened or loosened until the desired torque of the nut is reached.
[0047] See now Figure 6 This image shows a view of another embodiment of a chromatographic column 600, also referred to herein as column 600 or a dynamic axial compression column. Column 600 may include... Figure 3 The components and features of column 300 are shown in the image. However, Figure 6 The column 600 shown may include one or more equalizing plates 602. The equalizing plate 602 may include an intermediate component located between the compression device 330 and one of the end plate assemblies 306, 308. In some embodiments where each of the end plate assemblies 306, 308 is movable relative to the tube 302, and as... Figure 7 As shown, the first equalizer plate 602-A may be located between the first compression device 330-A and the first end plate assembly 306, and the second equalizer plate 602-B may be located between the second compression device 330-B and the second end plate assembly 308.
[0048] exist Figure 6 In this embodiment, the equalization plate 602 is located between the compression device 330 and the first end plate assembly 306. The equalization plate 602 may include various shapes and sizes and may be made of various materials.
[0049] The equalizing plate 602 can be configured to receive force from the compression device 330 and apply this force equally on the surface of the end plate 310 in contact with the equalizing plate 602, and therefore equally on the end plate assemblies 306, 308 in contact with the equalizing plate 602. Therefore, in Figure 6 In the embodiment shown, the equalizing plate 602 transmits the force from the compression device 330 equally to the first end plate assembly 306.
[0050] In some embodiments, this equal application of force to the end plate 310 causes the end plate assemblies 306 and 308 to exert equal forces on the medium in the lumen 304. Furthermore, when the end plate assemblies 306 and 308 move relative to the tube 302, the equal application of force to the end plate 310 causes the end plate assemblies 306 and 308, and specifically, causes the insert 312 to move equally relative to the tube 302, such that the inward surfaces (those surfaces that contact the lumen) of the first and second inserts 312 and the glass frit 320 remain parallel and parallel.
[0051] See now Figure 8 The diagram illustrates a schematic depiction of the movement of a first endplate assembly 306 relative to a second endplate assembly 308 and a tube 302 in a series of chromatographic columns 800, which are also referred to herein as column 800 or dynamic axial compression column 800. Figure 8 A single column 800 is depicted in three different locations with a first endplate assembly 306. Column 800 includes a tube 302 defining a lumen 304. The lumen 304 is filled with a medium 802. The medium may be compressible or incompressible. In some embodiments, the medium 802 may be an incompressible medium comprising at least one of the following: silica, alumina, zirconium oxide, glass, hydroxyapatite, and fluorapatite. In some embodiments, the medium 802 may comprise a solid product in the form of fine particles packed into the lumen 304 for use as a chromatography bed.
[0052] As described above, column 800 includes a first endplate assembly 306 and a second endplate assembly 308. The first endplate assembly 306 is biased toward the second endplate assembly 308 by a compression device 330. The compression device 330 applies pressure to the medium 802 filling the cavity 304 by applying a force to the first endplate assembly 306. This pressure applied to the medium can be less than the maximum pressure applied to the medium 802 without damaging, destroying, or fracturing the medium 802.
[0053] like Figure 8As seen, the first endplate assembly 306 of column 800-A is in a first position, the first endplate assembly 306 of column 800-B is in a second position, and the first endplate assembly 306 of column 800-C is in a third position. In some embodiments, each of the columns 800 may contain the same amount of medium 802, but the medium in columns 800-B and 800-C settles and / or compresses to a greater extent than the medium 802 in column 800-A. As the medium 802 settles, the compression device 330 applies a force to the first endplate assembly 306, causing the first endplate assembly 306 to advance from the first position to the second position, and subsequently to further compress and / or settle to the third position. Advancement of the first endplate assembly 306 into the lumen prevents the formation of cavities and / or endplate spaces. Therefore, this movement of the first endplate assembly 306 corresponds to compression of the chromatographic bed.
[0054] This description should not be construed as implying any particular order or arrangement of the various steps or elements, unless the order of the steps or the arrangement of the elements is explicitly described. Different arrangements of the components depicted in the drawings or described above, as well as components and steps not shown or described, are possible. Similarly, some features and sub-combinations are useful and can be used without reference to other features and sub-combinations. Embodiments of the invention have been described for illustrative and non-limiting purposes, and alternative embodiments will become apparent to the reader of this patent. Therefore, the invention is not limited to the embodiments described above or depicted in the drawings, and various embodiments and modifications may be made without departing from the scope of the claims below.
Claims
1. A dynamic axial compression column, comprising: The pipe, its limitations: First Open your mouth The second opening, and A lumen that extends from the first opening through the tube to the second opening; A first end plate assembly that seals the first opening and extends movably, at least partially, into the lumen via the first opening; The second end plate assembly seals the second opening; Multiple rods, each extending along the outer side of the tube and connecting the first end plate assembly and the second end plate assembly; as well as A first plurality of compression devices are located outside the tube, each of the first plurality of compression devices engaging one of the plurality of rods and biasing the first end plate assembly toward the second end plate assembly. Each of the first plurality of compression devices includes a spring.
2. The dynamic axial compression column according to claim 1, further comprising a medium filling the cavity.
3. The dynamic axial compression column according to claim 2, wherein the medium is compressible.
4. The dynamic axial compression column according to claim 2, wherein the medium is incompressible.
5. The dynamic axial compression column according to claim 4, wherein the medium comprises at least one of the following: Silicon dioxide; Alumina; Zirconium oxide; Glass; Hydroxyapatite; and Fluoroapatite.
6. The dynamic axial compression column of claim 4, wherein the first plurality of compression devices are configured to apply a first pressure to the medium filling the cavity.
7. The dynamic axial compression column of claim 6, wherein the first pressure is less than the maximum pressure applied to the medium without damaging the medium.
8. The dynamic axial compression column according to claim 1, wherein the plurality of rods comprises at least two rods.
9. The dynamic axial compression column according to claim 1, wherein the spring comprises a disc spring.
10. The dynamic axial compression column of claim 9, wherein the disc spring comprises a plurality of stacked discs.
11. The dynamic axial compression column of claim 10, wherein at least two of the plurality of stacked disks have opposite orientations.
12. The dynamic axial compression column of claim 1, further comprising a balancing plate positioned between the first plurality of compression devices and the first end plate assembly, the balancing plate being configured to transmit forces from the first plurality of compression devices equally to the first end plate assembly.
13. The dynamic axial compression column of claim 1, wherein the second end plate assembly extends at least partially into the lumen via the second opening in a movable manner.
14. The dynamic axial compression column according to claim 13, further comprising a second plurality of compression devices.
15. The dynamic axial compression column of claim 14, wherein each of the second plurality of compression devices is external to the tube, and wherein each of the second plurality of compression devices engages one of the plurality of rods and biases the second end plate assembly toward the first end plate assembly.
16. The dynamic axial compression column of claim 15, further comprising a second equalizing plate positioned between the second plurality of compression devices and the second end plate assembly, the second equalizing plate being configured to transmit forces from the second plurality of compression devices equally to the second end plate assembly.
17. The dynamic axial compression column of claim 1, wherein the first plurality of compression devices are configured to apply a first pressure to bias the first endplate assembly toward the second endplate assembly.
18. The dynamic axial compression column of claim 17, wherein the first pressure is equal to or greater than the back pressure in the column, thereby eliminating the generation of headspace.
19. The dynamic axial compression column according to claim 1, wherein the tube is circular.
20. The dynamic axial compression column of claim 19, wherein the tube has a diameter of at least three centimeters.
21. The dynamic axial compression column of claim 1, wherein the first end plate assembly includes a first inward surface, wherein the second end plate assembly includes a second inward surface, and wherein each of the first inward surface and the second inward surface is covered with glass frit.