Component and method for thermal field flow fractionation at high temperature

Abstract

The invention relates to a component for thermal field flow fractionation at high temperature of particles contained in a fluid, comprising at least one separating channel in which the fluid can be conducted, at least one supply channel (13) through which the fluid can be introduced into the separating channel, at least one discharge channel (14) through which the fluid can be discharged, a heatable wall unit (5) and a coolable wall unit (6). The separating channel is delimited at least by the heatable wall unit (5), the coolable wall unit (6) and a spacer (7), wherein the heatable wall unit (5) and the coolable wall unit (6) are formed from at least one thermally conductive material. In addition, at least one temperature-stable Peltier element (10) is provided, which is designed to form a temperature gradient parallel to the cross-sectional area perpendicular to the longitudinal direction of the separating channel by at least cooling the coolable wall unit (6), wherein the coolable wall unit (6) is arranged between the Peltier element (10) and the heatable wall unit (5), and the spacer (7) is arranged between the coolable wall unit (6) and the heatable wall unit (5).

Description

[0001] Component and method for thermal field flow fractionation at high temperatures

[0002] The present invention relates to a component and a method for thermal field flow fractionation at high temperature.

[0003] For the separation of polymers / particles soluble at high temperatures, column-based high-temperature chromatography has been and continues to be the standard method. "Chromatography" refers specifically to a process in which mixtures of substances are separated by different ionization.

[0004] The separation of a polymer into two immiscible phases, one stationary and the other mobile (i.e., a flowing fluid), is a common technique. However, this separation technique fails with (long-chain) branched and ultra-high-molecular-weight polymers. Field-flow fractionation (FFF) offers an alternative separation method that avoids the aforementioned problems encountered in column-based chromatography. Field-flow fractionation is specifically defined as a separation method in which the separation takes place in an open, laminarly flowed separation channel containing no stationary phase, and in which a separation force field is present perpendicular to the flow direction. This separation force field can be of various origins, such as a second fluid stream, centrifugal forces, the Earth's gravity, or a temperature gradient. FFF with a temperature gradient is called thermal field-flow fractionation (Th FFF).The concept of ThFFF was first patented and described in 1967. High-temperature ThFFF with classical temperature field generation (heating cartridges and circulating liquid cooling thermostat) was first successfully demonstrated on polyethylene in 1981. The separation of ultra-high molecular weight and branched polyolefins has so far only been demonstrated using high-temperature asymmetric flow field-flow fractionation (HT-AF4) as an alternative FFF.

[0005] US 3,449,938 A, for example, describes a method for separating mixed substances or materials using an upper and a lower thermally conductive plate, whereby the fluid flowing between the two units is subjected to a temperature gradient. A disadvantage of this separation process is that a significant amount of energy is required to cool one side and heat the other simultaneously. Previously, the temperature control of the channel-bounding plates was achieved separately through independent processes, resulting in low energy utilization and thus only a low efficiency.

[0006] The present invention is therefore based on the objective of proposing a component and a method for thermal field flux fractionation that both increases the efficiency of the utilization of the input energy and can be used at high temperatures and manufactured cost-effectively.

[0007] This problem is solved according to the invention by a component according to main claim 1 and by a method according to dependent claim 12. Advantageous embodiments and further developments are described in the dependent claims.

[0008] A component for the thermal field-flow fractionation of particles contained in a fluid at high temperature comprises at least one separation channel in which the fluid can be guided, at least one inlet channel through which the fluid can be introduced into the separation channel, at least one outlet channel through which the fluid can be discharged, a heated wall unit, and a cooled wall unit. The separation channel is bounded at least by the heated wall unit, the cooled wall unit, and a spacer, wherein the heated wall unit and the cooled wall unit are made of at least one thermally conductive material.Furthermore, at least one temperature-stable Peltier element is provided, which is configured to create a temperature gradient parallel to the cross-sectional area and perpendicular to the longitudinal direction of the separation channel by at least cooling the coolable wall unit, wherein the coolable wall unit is arranged between the Peltier element and the heated wall unit. Additionally, the spacer is arranged between the coolable wall unit and the heated wall unit.

[0009] Initially, "high temperature" is understood to refer specifically to ambient temperatures in the range of 40 °C to 400 °C. This means the component is located in an environment where the temperature lies within this range. Consequently, "temperature-stable" means that the Peltier elements used, and in particular all other units and components, can be used up to a temperature of 400 °C, or at least within a temperature range above 160 °C. The temperature ranges for the fluids used depend on their physical properties. Fluid temperatures of up to 400 °C can be achieved.

[0010] Furthermore, "inletable" and "outletable" are understood to mean that the fluid can be fed into the component from outside the component or discharged from inside the component to outside the component.

[0011] The use of a Peltier element, employed at least for cooling the coolable wall unit, enables space-saving and cost-effective production of the component for thermal field flow fractionation. Furthermore, the waste heat generated by the Peltier element can be used to heat the heated wall unit, thus allowing for more efficient temperature gradient generation. This means that, in this case, the temperature gradient across the cross-section of the separation channel is created on one side by cooling the coolable wall unit and on the other side by heating the heated wall unit. Both wall units must be made of thermally conductive materials, with "thermally conductive" defined as having a minimum thermal conductivity of 3 W / m*K.

[0012] The temperature gradient is formed parallel to the cross-sectional area and perpendicular to the longitudinal direction of the separation channel. The longitudinal direction of the separation channel coincides with the flow direction of the fluid being guided; that is, the temperature gradient is perpendicular to the fluid flow direction. The temperature gradient lies between 0 K and 250 K, typically in the range of 0 K to 130 K.

[0013] Furthermore, the term "spacer" can be understood as a unit that is in direct mechanical contact with the cooling unit via a first surface and with the heating unit via a second surface opposite the first surface. This means that the cooling unit and the heating unit are separated, at least via the spacer, in a direction perpendicular to the flow direction of the conveyed fluid. The spacer can be made of a heat-insulating material, i.e., a material with a thermal conductivity of < 3 W / m*K, preferably in the range of 0.5 W / m*K to 1 W / m*K. Additionally, the term "separation channel" can be understood as a cavity that forms as soon as the cooling unit, the heating unit, and the spacer are arranged as described.

[0014] Furthermore, the spacer can have at least one opening, in particular a circular, oval, or rectangular opening. The term "opening" can also refer to a complete penetration perpendicular to the fluid flow direction or perpendicular to the longitudinal direction of the separation channel. Thus, the geometry of the separation channel can be easily determined, at least by the chosen geometry of the opening in the spacer. At the same time, the height of the separation channel can be influenced by the thickness of the spacer, i.e., its extent perpendicular to the longitudinal direction of the separation channel. It is also possible that the coolable wall unit and / or the heated wall unit each have recesses in the area of ​​the spacer's opening that can influence the height of the separation channel.In particular, the spacer can have a thickness in the range of 10% to 50% of the thickness of the coolable or heated wall unit. Preferably, the separation channel can be flat, i.e., with a height of 70 pm to 500 pm, and more preferably 100 pm to 300 pm. The cross-sectional area perpendicular to the longitudinal direction of the separation channel and / or along the longitudinal direction of the separation channel can also be circular, oval, or rectangular.

[0015] Furthermore, the inner surface of the separation channel can be chemically inert. In this case, the "inner surface" of the separation channel can include the inner surface of the opening as well as the areas of the respective surfaces of the coolable wall unit and the heated wall unit that face the spacer and cover the area of ​​the spacer's opening. This prevents any chemical reactions from occurring between the separation channel and the fluid, thus keeping the fluid free of contamination. Moreover, this can significantly increase the durability and reliability of the component.

[0016] Furthermore, the coolable wall unit and the heated wall unit can be made of a metallic material, particularly copper. Using a metallic material improves thermal conductivity, thus increasing the component's efficiency. Typically, the thermal conductivity is at least 3 W / m*K.

[0017] Furthermore, at least one heating element can be integrated into and / or within the heated wall unit. "Within" here means that the heating element is enclosed by the heated wall unit for at least the length of the separation channel. The use of additional heating elements makes it possible to achieve higher temperature gradients in a shorter time. This further increases the efficiency of the component with regard to the overall fractionation time.

[0018] A housing is typically formed from thermally conductive housing elements, wherein at least the heated wall unit, the cooled wall unit, the spacer, the Peltier element, and, if present, a spacer for positioning the Peltier element are arranged within the housing. A heat dissipation device, preferably a heat sink, can be arranged outside the housing to cool the component.

[0019] The Peltier element can be designed as a duplex arrangement, so that the heated wall unit can be heated by the waste heat of the Peltier element, which is conveyed via the thermally conductive housing elements.

[0020] The Peltier element can be positioned below the heated wall unit to heat the heated wall unit and above the cooled wall unit.

[0021] A proposed chromatography system comprises at least one component for thermal field-flow fractionation with the properties described above. A "chromatography system" is understood to be, in particular, a system that has a fluid flow through a fluid line via gravity or a pump, that has a device for injecting polymers or particles to be separated, that has an element for separating polymers or particles to be separated, and that enables either detection or a device for collecting separated polymers or particles. Detection can be physical in nature (e.g., refractometric, light scattering, thermal or electrical conductivity, optical imaging), physicochemical in nature (e.g., spectroscopic, potentiometric, electrophoretic), or chemical in nature (e.g., detection by chemical conversion).The flow of the mobile phase is achieved either by pressure (pump in general, gas pressure), capillary action, or by applying an electrical voltage. By using the described component in existing chromatography systems, it is possible to easily expand the system's range of applications. Major modifications to the entire system are avoided, making integration into existing processes and systems cost-effective.

[0022] In a high-temperature thermal field-flow fractionation process, a fluid containing various particles flows through a feed channel into a separation channel, passes through the separation channel, and is then discharged through a discharge channel. The separation channel is bounded by at least one heated wall unit, one cooled wall unit, and a spacer. A temperature gradient parallel to the cross-sectional area of ​​the separation channel, which is oriented perpendicular to its longitudinal direction, is generated by cooling the cooled wall unit using at least one temperature-stable Peltier element. The cooled wall unit is positioned between the Peltier element and the heated wall unit, and the spacer is located between the cooled wall unit and the heated wall unit. The wall units are made of at least one thermally conductive material.As the fluid flows through the separation channel, the particles contained in the fluid are fractionated due to the temperature gradient through the superposition of induced thermal diffusion and translational diffusion.

[0023] Initially, "diverse" means that the particles differ in at least one characteristic; that is, the particles can exhibit dispersions in their properties (e.g., size, shape, density, mass or molecular mass, physical or chemical composition). This method has the advantage that reliable fractionation can still occur even at high ambient temperatures. Furthermore, the temperature gradient can be quickly generated and maintained by the Peltier element, thus accelerating the overall fractionation time.

[0024] Furthermore, the process can be carried out at ambient temperatures in the range of 40 °C to 400 °C, preferably in the range of 80 °C to 300 °C, and particularly preferably in the range of 120 °C to 220 °C, whereby the application of the channel in the range of 120 °C to 400 °C is ensured, and the process can therefore also be carried out under harsh environmental conditions. This significantly expands the possible areas of application of the process. Typically, however, the process is carried out at a temperature above 160 °C, whereby a maximum temperature of 400 °C is generally not exceeded.

[0025] Furthermore, the maximum temperature of the temperature gradient can be below the pressure-dependent boiling point of the fluid, with the internal pressure in the separation channel being at least equal to ambient pressure. This ensures that no chemical changes are induced in the fluid during the fractionation process, thus reducing the risk of an unintended chemical reaction. However, it is also possible for the maximum temperature of the temperature gradient to be above the normal-pressure boiling point of the fluid. In this case, the fluid's state of matter is maintained by an increased internal pressure in the separation channel. This internal pressure is higher than the vapor pressure of the fluid at the maximum temperature of the temperature gradient.

[0026] Finally, the particles can be dissolved at temperatures up to 220 °C, preferably within a temperature range of 80 °C to 180 °C, and / or the particles can be composed of polymers, in particular polyolefins, polystyrene, or polyesters. Thus, the method is suitable for all polymers or particles that can or must be analyzed at high temperatures—that is, polymers or particles that can only be dissolved or sufficiently dispersed at high temperatures, for example, within a range of 80 °C to 180 °C or 220 °C, or that possess other properties that only allow separation at high temperatures. These include, in addition to polyolefins and polystyrene, polyesters (polyesters of terephthalic acid, e.g., PET, PBT) or aromatic, n-conjugated polymers (e.g., organic / polymeric semiconductors).They can be analyzed to measure various parameters such as molar mass, size, shape, chemical composition, surface properties, etc., or to analyze their structural changes at high temperatures. This method allows polymers / particles to be separated and examined that would otherwise not be sufficiently separable in column-based liquid chromatography (LC) due to unwanted interactions with the column material.

[0027] The described procedure is typically designed to be carried out with the described component, i.e., the described component is suitable for carrying out the described procedure.

[0028] Exemplary embodiments of the invention are shown in the drawings and are described below with reference to Figures 1-14. Recurring features are identified by identical reference numerals.

[0029] They show:

[0030] Fig. 1 shows a schematic perspective exploded view of a first embodiment of the component with a duplex arrangement of Peltier elements;

[0031] Fig. 2 is a composite schematic side view of the first embodiment variant from Fig. 1;

[0032] Fig. 3 is a composite schematic frontal view of the first embodiment variant from Fig. 1;

[0033] Fig. 4 is a composite schematic perspective view of the first embodiment variant from Fig. 1;

[0034] Fig. 5 shows a schematic perspective exploded view of a second embodiment of the component with a sandwich arrangement of Peltier elements;

[0035] Fig. 6 is a composite schematic side view of the second embodiment variant from Fig. 5;

[0036] Fig. 7 is a composite schematic frontal view of the second embodiment from Fig. 5; Fig. 8 is a composite schematic perspective view of the second embodiment from Fig. 5;

[0037] Fig. 9 shows a schematic perspective exploded view of a third embodiment of the component with a duplex arrangement of Peltier elements and additional heating elements;

[0038] Fig. 10 is a composite schematic side view of the third embodiment variant from Fig. 9;

[0039] Fig. 11 is a composite schematic frontal view of the third embodiment variant from Fig. 9;

[0040] Fig. 12 is a composite schematic perspective view of the third embodiment variant from Fig. 9;

[0041] Fig. 13 shows a schematic perspective exploded view of a coolable wall unit, a heated wall unit, and a spacer with an opening; and

[0042] Fig. 14 shows a schematic top view of a spacer with an opening.

[0043] Fig. 1 shows a schematic perspective exploded view of a first embodiment of the component, in which thermally conductive housing elements 3 are formed from a metallic material and connected by a plurality of fastening elements 2. The metallic material of the housing elements 3 ensures heat conduction. Heat is dissipated, among other things, via the uppermost housing element 3 to a heat sink 1 located above it. Thus, the heat sink 1 contributes to cooling the entire component. The component shown in Fig. 1 can, for example, be part of a chromatography system for thermal field-flux fractionation.

[0044] Furthermore, flexible heat transfer elements 4 can be provided between the side housing elements 3 and the upper housing element 3 to ensure sufficient heat transfer between the housing elements 3. Additionally, a coolable wall unit 6 with a supply channel 13 is formed within the housing, which in this embodiment is primarily composed of the housing elements 3. A fluid can be introduced into a separation channel via the supply channel 13. The separation channel is bounded by a spacer 7 with an opening 15, a heated wall unit 5, and the coolable wall unit 6. The separation channel can thus be understood as a cavity that forms in the assembled state (see, for example, Fig. 2) between the coolable wall unit 6 and the heated wall unit 5. This cavity is created by the opening 15 in the spacer 7.In this embodiment, the supply channel 13 has a circular cross-section perpendicular to the longitudinal direction of the separation channel. Alternatively, it can also be oval or rectangular. A discharge channel 14 is shown here only as a concealed element. Both the coolable wall unit 6 and the heated wall unit 5 can have a supply channel 13 and / or a discharge channel 14.

[0045] In this embodiment, the separation channel is defined by the thickness of the spacer 7, i.e., by its extent perpendicular to the longitudinal direction of the separation channel, and by the shape of the opening 15 in the spacer 7. Here, the separation channel is flat, as defined above, meaning it has a height of 70 pm to 500 pm. Furthermore, the length of the separation channel is 28 cm, with a minimum length of 7 cm. Preferably, the length is in the range of 15 cm to 100 cm. The inner surface of the separation channel, i.e., the surfaces of the coolable wall unit 6, the heated wall unit 5, and the inner surface of the opening 15, which are wetted by a fluid, is chemically inert in the illustrated embodiment.

[0046] The coolable wall unit 6 is made of a thermally conductive material, in this embodiment copper. However, any other material with a thermal conductivity greater than 3 W / m*K can be used. Metal materials are preferred because they have a significantly higher thermal conductivity, allowing for more efficient heat transfer.

[0047] In this embodiment, a plurality of Peltier elements 10 in a duplex arrangement are located directly below the coolable wall unit 6 in direct mechanical contact with it. The Peltier elements 10 enable the coolable wall unit 6 to be cooled quickly and effectively.

[0048] The Peltier elements 10 have a relatively low energy efficiency, meaning that the heat flow generated by the Peltier elements 10 is always less than the electrical power input. The difference between the power input and the effectively achieved heat flow (power loss) is released as additional heat on the hot side of the Peltier elements 10. The duplex arrangement allows for efficient energy utilization because it uses the heat from the hot side of the Peltier elements 10, via the housing elements 3, to heat the hot channel wall, i.e., the heatable wall unit 5. The longer heat conduction path via the housing elements 3 and the associated thermal resistance are compensated for by the additional heat generated as power loss.

[0049] Below the Peltier elements 10, a heat-insulating spacer 9 is arranged. This spacer 9 prevents the Peltier elements 10 from coming into contact with each other and also prevents the electrical leads of the Peltier elements 10 from coming into direct contact with hot components. This ensures a safe and stable operation of the fractionation process.

[0050] Furthermore, the heated wall unit 5 is arranged above the coolable wall unit 6. In this embodiment, the heated wall unit 5 is heated by the waste heat released by the Peltier elements 10 during the cooling of the coolable wall unit 6. This waste heat is conducted to the heated wall unit 5 via the housing elements 3. The heated wall unit 5 is also made of a metallic material, resulting in increased thermal conductivity, i.e., at least 50 W / m*K. The spacer 7 is made of a heat-insulating material with a thermal conductivity typically < 3 W / m*K. The spacer 7 ensures that the heated wall unit 5 does not come into direct mechanical contact with the coolable wall unit 6, thus increasing the efficiency of the separation process.The spacer 7 has a differently configurable opening 15, which determines the channel height and lateral boundaries of the separation channel. The opening 15 of the spacer 7 is filled with fluid during operation of the separation process. Alternatively, the height of the separation channel can also be influenced via designated recesses in the heated wall unit 5 and / or the cooled wall unit.

[0051] In this embodiment, the heated wall unit 5, the spacer 7, and the cooled wall unit 6 are fixed within the housing and relative to each other by positioning elements 8, thus preventing any misalignment of the components. These positioning elements 8 can be designed, for example, as pins or pin-shaped units, or as raised edges on the perimeter of the wall units 5 and 6. The advantage of using the positioning elements 8 is that it ensures improved handling, secure assembly, and a fixed position during operation.

[0052] In this embodiment, a temperature gradient parallel to the cross-sectional area and perpendicular to the longitudinal direction of the separation channel, i.e., perpendicular to the fluid flow direction, is generated by the active direct cooling of the coolable wall unit 6 by the Peltier elements 10 and by the indirect heating of the heated wall unit 5 by the waste heat generated by the Peltier elements 10. This temperature gradient thus fractionates the particles contained in the fluid through the superposition of induced thermal diffusion and translational diffusion.

[0053] The subsequent detection of the particles fractionated in the fluid is carried out by detectors arranged at the outlet of the discharge channel 14 (not shown). These provide the concentration of the respective particles in the fluid in real time and continuously. Information about the respective particles in the fluid can be obtained, for example, via physicochemical (e.g., concentration, size, molar mass, charge state, viscosity in solution, chemical composition), physical (e.g., refractive, light scattering, thermal or electrical conductivity, optical imaging), physicochemical (e.g., spectroscopic, potentiometric, electrophoretic), or chemical measurement methods (e.g., detection by chemical conversion).

[0054] Figures 2, 3, and 4 show the embodiment described above in an assembled state, in side, front, and perspective views. Figures 2 and 4, for example, indicate electrical leads leading out of the component. These provide the electrical connection to the Peltier elements 10. At least one measuring device, control device, and / or regulating device can be connected to these electrical connections to control the process and adapt it individually to the respective fractionation tasks.

[0055] Fig. 5 shows a second embodiment, which differs from the first in that the Peltier elements 10 are arranged in a layered configuration. Here, the Peltier elements 10 located below the coolable wall unit 6 are used to actively and directly cool the coolable wall unit 6. In addition, the Peltier elements 10 located above the heated wall unit 5 actively and directly heat the heated wall unit 5. Besides the direct heating of the heated wall unit 5, it is also indirectly heated by the waste heat, as in the first embodiment. In all embodiments, "direct" refers to immediate heating or cooling, characterized by the fact that no additional component is provided for heat conduction between the Peltier elements 10 and the heated wall unit 5 or the coolable wall unit 6. Accordingly, "indirect" refers to the fact that the heat supply or cooling is not directly conducted.Heat dissipation occurs at least via an intermediate component. The heating of the heated wall unit 5 can be increased, if necessary, by additional heating elements 11.

[0056] The advantages of a layered arrangement are that if sufficient heat conduction via the housing elements 3 cannot be guaranteed, e.g. due to excessive heat loss at the lower housing element 3 to the environment (contact surface), a higher temperature difference is achieved with the layered arrangement compared to the duplex arrangement.

[0057] In the following Figures 6, 7, and 8, the component in the second embodiment is shown in its assembled state in side, front, and perspective views, analogous to the first embodiment. The electrical lines for controlling and regulating the installed Peltier elements 10 are also indicated.

[0058] Fig. 9 shows a third embodiment, in which the Peltier elements 10 are again configured as a duplex arrangement for cooling the coolable wall unit 6. However, in contrast to the first embodiment, the coolable wall unit 6 is located above the heated wall unit 5. Additionally, the heating of the heated wall unit 5 is now enhanced by integrated electric heating elements 11. This allows for an even higher temperature gradient than in the first and second embodiments, which can also be controlled more precisely. Alternatively, it is also possible to combine the layered arrangement of the Peltier elements 10 described above (second embodiment) with the use of integrated electric heating elements 11 in the wall unit 6.

[0059] Furthermore, this embodiment also includes heat-insulating housing elements 12, which prevent heat transfer via these housing elements 12. This prevents waste heat from being released to the environment. Therefore, the heating of the heated wall unit 5 by heating elements 11 can be made more efficient. This also means that, in this embodiment, the indirect heating of the heated wall unit 5 by the waste heat emanating from the Peltier elements 10 is prevented. However, it is also possible to replace the heat-insulating (< 3 W / m*K) housing elements 12 with thermally conductive (> 3 W / m*K) housing elements 3 made of, for example, a metallic material. In this case, indirect heating is again permitted. Analogous to the previous embodiments, this is shown in Figs. 10, 11, and 12.Figure 12 shows the component according to the third design variant in its assembled state in side, front, and perspective views. In addition to the electrical lines supplying the Peltier elements 10, the electrical heating elements 11 are now also shown. This design variant makes it possible to control and regulate the heating and cooling separately.

[0060] Fig. 13 further illustrates that the separation channel is formed by the spacer 7, the coolable wall unit 6, and the heated wall unit 5. The channel geometry, as described in detail above, is primarily determined by the thickness of the spacer 7 and the shape of the opening 15 in the spacer 7 (an exemplary shape is shown in Fig. 14). Furthermore, Fig. 13 illustrates that the supply channel 13, which in this embodiment is located in the coolable wall unit 6, has an inlet opening (through which the fluid is introduced) and an outlet opening (through which the fluid enters the separation channel). In this embodiment, the cross-section of the supply channel in the region of the inlet opening is therefore perpendicular to the longitudinal direction of the separation channel. The cross-section of the supply channel 13 in the region of the outlet opening, however, is oriented parallel to the longitudinal direction of the separation channel.This means that the fluid supply line runs at a 90° angle within the coolable wall unit 6. The discharge channel 14 (where only the inlet opening is shown here) is arranged in reverse on the opposite side, i.e., at the other end of the separation channel, also within the coolable wall unit 6. Alternatively, in this embodiment, the fluid could also be discharged via the supply channel 13 and introduced through the discharge channel 14. Furthermore, supply channels 13 and / or discharge channels 14 can also be provided in the heated wall unit 5.

[0061] In summary, the separation of polymers or particles in solution is achieved through the effect of thermophoresis, i.e., the mass transport of particles due to a temperature gradient within a fluid, induced by a temperature gradient between the top and bottom surfaces of a flat, ribbon-like separation channel. Through induced thermal diffusion towards a channel wall and the opposing translational diffusion, polymers or particles with different characteristics relax into layers at varying distances from the accumulation wall. Here, the "accumulation wall" refers specifically to the surface of the separation channel where the particles in the fluid predominantly reside due to thermophoretic mass transport. Depending on the direction of thermophoresis, this can be either the colder or the warmer wall.These fractions are eluted from the channel at different times when a channel flow with laminar fluid flow (Reynolds number < 2320) is applied, since the mean relaxation heights correspond to flow layers with different flow velocities. The relaxation height can be understood, in particular, as the distance from the accumulation wall that is established in steady state at the equilibrium between thermal and translational diffusion under the influence of the temperature gradient, at which the center of gravity of the particle distribution in the fluid is statistically located. Due to the absence of a stationary phase, no unwanted interactions or inhibited chromatographic separation occur during particle separation. The method is typically used at an ambient temperature in the range of 40 °C to 400 °C, and the temperature field is generated using the described temperature-stable Peltier elements 10.

[0062] Only features disclosed in the exemplary embodiments can be combined and claimed individually.

[0063] Heat sink 1

[0064] Fastening element 2

[0065] Thermally conductive housing element 3

[0066] Flexible heat transfer element 4

[0067] Heated wall unit 5

[0068] Coolable wall unit 6

[0069] Spacer 7 with opening 15

[0070] Positioning element 8

[0071] Heat-insulating spacer 9

[0072] Peltier element 10 Electric heating element 11

[0073] Heat-insulating housing element 12

[0074] Supply channel l3

[0075] Drainage channel 14

Claims

Patent claims 1. Component for thermal field-flow fractionation of particles contained in a fluid at high temperature, comprising: at least one separation channel in which the fluid can be guided, at least one inlet channel (13) through which the fluid can be introduced into the separation channel and at least one outlet channel (14) through which the fluid can be discharged, a heatable wall unit (5), a coolable wall unit (6) and a spacer (7), wherein the separation channel is bounded at least by the heatable wall unit (5), the coolable wall unit (6) and the spacer (7), wherein the heatable wall unit (5) and the coolable wall unit (6) are made of at least one thermally conductive material, and at least one temperature-stable Peltier element (10) which is configured to form a temperature gradient parallel to the cross-sectional area perpendicular to the longitudinal direction of the separation channel by at least cooling the coolable wall unit (6).wherein the coolable wall unit (6) is arranged between the Peltier element (10) and the heated wall unit (5), and wherein the spacer (7) is arranged between the coolable wall unit (6) and the heated wall unit (5).

2. Component for thermal field flux fractionation according to claim 1, characterized in that the spacer (7) has an opening (15), in particular a circular or oval or rectangular opening (15).

3. Component for thermal field flow fractionation according to one of the preceding claims, characterized in that the inner surface of the separation channel (13) is chemically inert.

4. Components for thermal field flux fractionation according to one of the preceding claims, characterized in that the coolable wall unit (6) and the heated wall unit (5) are made of a metallic material, in particular copper.

5. Component for thermal field flow fractionation according to one of the preceding claims, characterized in that at least one heating element (11) is formed within and / or on the heatable wall unit (5).

6. Component for thermal field flux fractionation according to one of the preceding claims, characterized in that a housing is formed from thermally conductive housing elements (3), wherein at least the heated wall unit (5), the coolable wall unit (6), the spacer (7), the Peltier element (10) are arranged inside the housing.

7. Component for thermal field flux fractionation according to one of the preceding claims, characterized in that a spacer (9) for positioning the Peltier element (9) is arranged inside the housing.

8. Component for thermal field flux fractionation according to one of the preceding claims, characterized in that a heat dissipation device (1) for cooling the component is designed outside the housing.

9. Component for thermal field flow fractionation according to one of the preceding claims, characterized in that the Peltier element (10) is designed as a duplex arrangement, so that the heatable wall unit (5) can be heated by the waste heat of the Peltier element (10) supplied via the thermally conductive housing elements (3).

10. Component for thermal field flow fractionation according to one of claims 1 to 8, characterized in that the Peltier element (10) is arranged below the heatable wall unit (5) for heating the heatable wall unit (5) and above the coolable wall unit (6).

11. Chromatography system with at least one component for thermal field flux fractionation according to one of claims 1 - 10.

12. A method for thermal field flow fractionation at high temperature, in which a fluid containing various types of particles is introduced into a separation channel through a feed channel (13), then flows through the separation channel and is finally discharged through a discharge channel (14), wherein the separation channel is bounded by at least one heatable wall unit (5), one coolable wall unit (6) and a spacer (7), and wherein a temperature gradient parallel to the cross-sectional area of ​​the separation channel oriented perpendicular to the longitudinal direction of the separation channel is generated by at least the cooling of the coolable wall unit (6) by at least one temperature-stable Peltier element (10), wherein the coolable wall unit (6) is located between the Peltier element (10) and the heatable wall unit (5), and the spacer (7) is located between the coolable wall unit (6) and the heatable wall unit (5). is arranged, wherein the wall units (5, 6) are made of at least one thermally conductive material and, when flowing through the separation channel, the particles contained in the fluid are fractionated due to the temperature gradient by the superposition of induced thermal diffusion and translational diffusion.

13. Method for thermal field flux fractionation according to claim 12, characterized in that the method is carried out at ambient temperatures in a range of 40 °C - 400 °C, preferably in a range of 80 °C - 300 °C, particularly preferably in a range of 120 °C - 220 °C.

14. Method for thermal field flow fractionation according to one of claims 12-13, characterized in that a maximum temperature of the temperature gradient is below a pressure-dependent boiling point of the fluid, wherein an internal pressure in the separation channel corresponds at least to the ambient pressure.

15. Method for thermal field flow fractionation according to one of claims 12-14, characterized in that the particles contained are dissolved in a temperature range of 80 °C to 180 °C and / or the particles are formed from polymers, in particular from polyolefins, polystyrene or polyesters.

Images