A stirling cryogenic heat modulator module for replacing a peltier heat modulator

Abstract

The present application relates to the technical field of gas chromatography analysis instrument, and discloses a Stirling cryogenic thermal modulation module for replacing a Peltier thermal modulator, which comprises a module main body, a metal modulation pipe unit, a Stirling cryogenic refrigeration unit, a flexible heat conduction assembly, a direct contact type rapid flash evaporation temperature control unit, a control interface unit, a signal level conversion unit, a time sequence mapping unit, a temperature feedback unit and an elastic support assembly; the metal modulation pipe body is connected with first and second chromatographic columns and serves as a low-heat-capacity controlled temperature modulation section, the cold head transmits cold to the metal modulation pipe body through the flexible heat conduction assembly and forms a non-rigid connection, and the direct contact type rapid flash evaporation temperature control unit is directly attached, crimped, clamped or formed on the outer wall of the metal modulation pipe body; the module can realize replacement and upgrading under the condition of retaining the original installation position, column connection relationship and control logic, and reduce the additional heat capacity, cold return waiting time and cold head vibration influence.

Description

Technical Field

[0001] This invention relates to the field of gas chromatography analysis instrument technology, and more particularly to a thermal modulation device in a full two-dimensional gas chromatography system, specifically to a Stirling cryogenic thermal modulation module and its control method for replacing the Peltier thermal modulator. Background Technology

[0002] Two-dimensional gas chromatography improves the separation capability of complex samples by placing a modulator between the first and second chromatographic columns to periodically capture, focus, and release the sample stream flowing out of the first column, allowing the sample components to enter the second column in a narrow band. The thermal modulator is a key component in a two-dimensional gas chromatography system, and its performance affects the capture of low-boiling-point components, peak shape, modulation period stability, and subsequent qualitative and quantitative results.

[0003] Existing thermal modulators can employ liquid nitrogen, liquid carbon dioxide, semiconductor refrigeration chips, or other cooling methods. Liquid nitrogen or liquid carbon dioxide solutions can provide lower temperatures, but require continuous consumption of the refrigerant and involve storage, transportation, and supply maintenance. Peltier thermal modulators have advantages such as being solid-state, compact, and easy to maintain, and have been used in some full two-dimensional gas chromatography systems. However, the cryogenic capability of Peltier refrigeration chips is limited by materials and heat transfer conditions, and they are insufficient for the cryogenic capture of components such as low-boiling-point light hydrocarbons.

[0004] Existing technologies also include solutions that use a reverse Stirling cycle refrigerator as the cold source for the thermal modulator. These solutions mainly focus on the cold zone, collection section, and pulse heating structure of the thermal modulator itself, demonstrating that the Stirling refrigerator can serve as a low-temperature cold source for the thermal modulator. However, for existing full two-dimensional gas chromatography systems that have already installed Peltier thermal modulators, actual upgrades still face compatibility issues such as installation hole positions, column connection locations, host trigger signals, original gas chromatography method documents, and recooling safety assessments.

[0005] Furthermore, the cold head of a Stirling refrigerator typically generates mechanical vibration due to the reciprocating motion of the piston. If the cold head is rigidly connected to the modulation tube or column system, the vibration may be transmitted to the connection between the modulation tube and the column, affecting peak shape and separation stability. At the same time, if the flash heating section indirectly heats the modulation section through an additional, larger intermediate heat transfer structure, it will increase the heat capacity and heat transfer hysteresis, affecting the heating and cooling rates. Therefore, a modular solution is needed for upgrading existing Peltier thermal modulators, which can improve low-temperature capture capabilities and reduce the impact of vibration and heat capacity while retaining the original installation location, column connection relationship, and control logic. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a Stirling cryogenic thermal modulation module and its control method for replacing the Peltier thermal modulator, so that the Stirling cryogenic cooling capacity can be connected to the existing full two-dimensional gas chromatography system in a replacement upgrade manner, and complete low-temperature capture, rapid flash release and recooling confirmation under the condition of retaining the original installation position, the original column connection relationship and the original gas chromatography host trigger logic, while reducing the impact of Stirling cold head vibration on the column system.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A Stirling cryogenic thermal modulation module for replacing Peltier thermal modulators includes a module body, a metal modulation tube unit, a Stirling cryogenic refrigeration unit, a flexible heat conduction component, an elastic support component, a direct contact rapid flash temperature control unit, a control interface unit, a signal level conversion unit, a timing mapping unit, and a temperature feedback unit.

[0008] The main body of the module includes an installation and positioning section configured to match the mounting holes, mounting brackets, or mounting space of the original Peltier heat modulator in the full two-dimensional gas chromatography system, so that the Stirling cryogenic heat modulator module can be installed at the original Peltier heat modulator's mounting position. The metal modulator tube unit has a first column connection interface, a second column connection interface, and a metal modulator tube body connected between the two. The first column connection interface is used to connect to the first column, and the second column connection interface is used to connect to the second column. The outer diameter of the connection end of the metal modulator tube body is adapted to the outer diameter of the connection ends of the first and second columns. The Stirling cryogenic refrigeration unit includes a cold head, a flexible heat conduction component connecting the cold head and the metal modulator tube unit, used to transfer the cold energy generated by the cold head to the metal modulator tube body, and to form a non-rigid mechanical connection between the cold head and the metal modulator tube unit. An elastic support component is used to support the metal modulator tube unit and reduce the mechanical vibration of the cold head transmitted to the first and second columns. A direct contact rapid flash temperature control unit is in direct thermal contact with the metal modulator tube body, used to directly and rapidly control the temperature rise of the metal modulator tube body.

[0009] The control interface unit has a signal input terminal, which matches the signal type, level range, and trigger logic of the control output terminal originally used by the gas chromatograph host to control the Peltier thermal modulator. The signal level conversion unit converts the trigger signal received by the signal input terminal into the drive signal of the direct contact rapid flash temperature control unit. The timing mapping unit maps the single modulation trigger timing of the original Peltier thermal modulator to the cryogenic hold timing, rapid flash trigger timing, and recooling confirmation timing of the metal modulation tube body while keeping the modulation cycle parameters in the original gas chromatograph method file unchanged. The temperature feedback unit detects the temperature of the metal modulation tube body or the metal modulation tube unit and prohibits or delays the next rapid flash trigger if the metal modulation tube body has not recooled to the set low temperature capture range.

[0010] Preferably, the module body includes an installation positioning part adapted to the original Peltier heat modulator mounting holes, mounting bracket or installation space, and the first column connection interface and the second column connection interface are adapted to the column connection positions corresponding to the original Peltier heat modulator. Thus, the module can be installed at the original modulator mounting position without changing the main structure of the gas chromatograph host and the original column connection relationship.

[0011] Preferably, the outer diameter of the connecting end of the metal modulation tube body is adapted to the outer diameter of the connecting ends of the two chromatographic columns. The first chromatographic column, the metal modulation tube body, and the second chromatographic column are arranged along the same axis at the connection point and have the same or substantially the same outer diameter. The metal modulation tube body can be a thin-walled stainless steel capillary, a nickel-based alloy capillary, a titanium alloy capillary, or other metal capillary with an inert inner wall treatment. The inner diameter of the metal modulation tube body can be 0.25 mm to 2.0 mm, and the length can be 5 mm to 50 mm. An inert coating can be provided on the inner wall of the metal modulation tube body.

[0012] Preferably, the direct contact rapid flash evaporation temperature control unit includes one or more of the following: a metal thin film resistive layer, a resistance heating element, a clamping heating block, a sleeve heating block, or a printed resistive track, formed on, attached to, pressed onto, or clamped on the outer wall of the metal modulation tube body; the direct contact rapid flash evaporation temperature control unit is configured to directly input heat to the metal modulation tube body after receiving the flash evaporation drive signal, so that the metal modulation tube body rapidly heats up from a low temperature trapping state to a sample release state.

[0013] Preferably, the signal input terminal of the control interface unit can receive synchronization line signals, valve event signals, dry contact signals, TTL signals, relay output signals, or trigger signals converted by the communication interface. The signal level conversion unit may include an isolation input circuit, a level conversion circuit, a pulse shaping circuit, and a power drive circuit.

[0014] Preferably, the timing mapping unit includes a low-temperature stability judgment module, a flash evaporation trigger module, a recooling confirmation module, and an abnormal trigger shielding module; the low-temperature stability judgment module is used to determine whether the metal modulation tube body has reached the set low-temperature collection range; the flash evaporation trigger module is used to drive the direct contact rapid flash evaporation temperature control unit according to the converted trigger signal; the recooling confirmation module is used to confirm whether the metal modulation tube body has returned to the set low-temperature collection range after flash evaporation; the abnormal trigger shielding module is used to prohibit or delay rapid flash evaporation triggering when there is no recooling, over-temperature, under-temperature, trigger signal interval is less than the set minimum time, trigger pulse width exceeds the set range, or trigger level exceeds the set range.

[0015] Preferably, the flexible heat conduction component includes one or more of the following: copper braided tape, flexible heat pipe, multi-strand soft copper tape, flexible heat-conducting sheet, flexible graphite heat-conducting sheet, or a heat-conducting component formed by combining a flexible heat-conducting element and a heat-conducting clamping block. The flexible heat conduction component has a bending allowance so that minor vibrations of the cold head relative to the metal modulation tube unit are not directly transmitted to the metal modulation tube body and the two chromatographic columns through a rigid connection; the thermal resistance of the flexible heat conduction component between the cold head and the metal modulation tube unit can be no greater than 0.5 K / W.

[0016] Preferably, the Stirling deep cryogenic modulation module further includes a cold zone insulation component, which surrounds at least part of the outside of the cold zone formed by the cold head, the flexible heat conduction component, and the low-temperature trapping section of the metal modulation tube body; the cold zone insulation component may be one or more of the following: insulation layer, insulation cover, insulation shell, or insulation cavity, to reduce the heat transfer from the external environment to the cold zone.

[0017] Preferably, the elastic support assembly includes one or more of the following: elastic gasket, bellows, vibration damping pad, elastic clamp, vibration isolation support, or elastic suspension. The metal modulation tube unit is supported within the gas chromatography column oven or module body by the elastic support assembly, and the cold head is supported by an independent support structure, thus separating the support path of the cold head from the support path of the metal modulation tube unit.

[0018] Preferably, the temperature feedback unit includes a temperature sensor disposed on the metal modulation tube body, the cold conduction clamping part, or near the metal modulation tube body, and a controller connected to the temperature sensor. The temperature sensor may be a Pt100 temperature sensor, a thermocouple, a thin film temperature sensor, or other temperature detection element suitable for low temperature and rapid temperature change environments. The controller may adjust the cooling power of the Stirling cryogenic refrigeration unit and / or the heating output of the direct contact rapid flash temperature control unit according to the temperature of the metal modulation tube body or the metal modulation tube unit.

[0019] This invention also provides a Stirling cryogenic modulation control method based on the original Peltier modulator control signal. While maintaining the modulation cycle parameters in the original gas chromatography method file unchanged, the method includes: installing the Stirling cryogenic modulation module at the original Peltier modulator installation position in the full two-dimensional gas chromatography system, and connecting the metal modulation tube body between the first and second chromatographic columns; receiving the trigger signal originally used by the gas chromatography host to control the Peltier modulator through a control interface unit; and performing level conversion and pulse shaping on the trigger signal to obtain a direct contact rapid flash temperature control module. The driving signal of the element; during the capture phase of the modulation cycle, the cold head of the Stirling cryogenic refrigeration unit and the flexible heat conduction components keep the metal modulation tube body within the set low temperature capture range; after receiving a trigger signal that meets the trigger conditions, the direct contact rapid flash evaporation temperature control unit is driven to rapidly release the captured components in the metal modulation tube body and enter the second chromatographic column; after flash evaporation, the heating output is stopped, and the cooling process of the metal modulation tube body is monitored through the temperature feedback unit; when the metal modulation tube body has not cooled back to the set low temperature capture range, the next trigger is prohibited, delayed, or an alarm is triggered.

[0020] The present invention also provides a fully two-dimensional gas chromatography system, including a gas chromatography main unit, a first chromatographic column, a second chromatographic column, and the aforementioned Stirling cryogenic modulation module. The metal modulation tube body is connected between the first and second chromatographic columns. The control output terminal of the gas chromatography main unit, originally used to control the Peltier thermal modulator, is connected to the signal input terminal of the control interface unit.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects: This invention does not simply replace the cold source of the thermal modulator with a Stirling refrigerator. Instead, it incorporates the original Peltier thermal modulator installation location, the original column connection relationship, the original gas chromatograph main unit trigger output, the original modulation cycle logic, the metal modulation tube body, and the direct contact rapid flash temperature control unit into the same modular solution. This allows the Stirling cryogenic thermal modulation module to be connected to the existing full two-dimensional gas chromatography system in a replacement and upgrade manner, while also preserving the original column connection relationship and flow path continuity.

[0022] In this invention, the control interface unit, signal level conversion unit, and timing mapping unit work together to convert the trigger signal originally used by the gas chromatograph host for the Peltier thermal modulator into a deep cryogenic hold, rapid flash evaporation trigger, and recooling confirmation timing sequence, which can reduce the need to rewrite the gas chromatograph method file and rearrange the control logic.

[0023] In this invention, the flexible heat conduction component transfers cold energy between the cold head and the metal modulation tube unit and forms a non-rigid mechanical connection. The elastic support component supports and isolates the metal modulation tube unit, thereby suppressing the transmission of Stirling cold head vibration to the metal modulation tube body, the first chromatographic column, and the second chromatographic column.

[0024] In this invention, the metal modulation tube itself serves as a low-heat-capacity temperature-controlled modulation section. The direct-contact rapid flash evaporation temperature control unit directly heats the metal modulation tube, reducing additional intermediate heat transfer links and additional heat capacity. The temperature feedback unit works in conjunction with the timing mapping unit to prohibit or delay the next rapid flash evaporation trigger when the metal modulation tube has not cooled back to the set low-temperature collection range. This helps to reduce insufficient collection and modulation cycle drift caused by insufficient cooling.

[0025] In this invention, the cold zone insulation component is installed on at least part of the outside of the cold zone formed by the cold head, the flexible heat conduction component and the low-temperature trapping section of the metal modulation tube body. This can reduce the heat transfer from the external environment to the cold zone and reduce the loss of cold energy, which is beneficial to reducing the additional cooling load of the Stirling cryogenic refrigeration unit and improving the stability of the low-temperature trapping state.

[0026] In an embodiment of the present invention where the low-temperature capture range is set to -150°C to -180°C, the metal modulation tube body can provide deeper cold capture conditions for low-boiling-point components, which is beneficial to expanding the modulation application range of low-boiling-point components such as light hydrocarbons. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of a Stirling cryogenic modulation module according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the connection and control structure of the Stirling cryogenic modulation module and the full two-dimensional gas chromatography system according to an embodiment of the present invention; Figure 3 This is a partially enlarged structural diagram of the metal modulation tube, the direct contact rapid flash evaporation temperature control unit, the flexible heat conduction component, and the elastic support component according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the modulation period timing and temperature variation according to an embodiment of the present invention; Figure 5 This is a flowchart of a Stirling cryogenic modulation control method according to an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the cooperation relationship between the cold zone insulation component, the cold head, the flexible heat conduction component, and the metal modulation tube body according to an embodiment of the present invention.

[0028] In the diagram: 100, Stirling cryogenic modulation module; 10, module body; 11, mounting and positioning part; 20, metal modulation tube unit; 21, first chromatographic column connection interface; 22, second chromatographic column connection interface; 23, metal modulation tube body; 24, inert coating; 30, Stirling cryogenic refrigeration unit; 31, cold head; 32, independent support structure; 33, cold zone insulation component; 40, flexible heat conduction component; 50, direct contact rapid flash evaporation temperature control unit; 60, control interface unit; 61, signal input terminal; 62, isolation input circuit; 63, level conversion circuit; 64, pulse shaping circuit; 65, power drive circuit; 66, signal level conversion unit; 70, timing mapping unit; 71, low temperature stability judgment module; 72, flash evaporation trigger module; 73, recooling confirmation module; 74, abnormal trigger shielding module. 80. Temperature feedback unit; 81. Temperature sensor; 82. Controller; 90. Elastic support assembly; 91. Elastic gasket; 92. Bellows; 93. Vibration isolation support; 200. Full two-dimensional gas chromatography system; 201. Gas chromatography main unit; 202. First chromatographic column; 203. Second chromatographic column; 204. Control output terminal; 101. Modulation cycle; 102. Original trigger signal; 103. Time-series mapping output signal; 104. Rapid flash evaporation drive signal; 105. Temperature curve of metal modulation tube; 106. Cryogenic holding stage; 107. Rapid flash evaporation stage; 108. Component release stage; 109. Cooling stage; 110. Low temperature ready stage; 111. Cooling output status signal; 112. Cycle start point; 113. Set the lower limit of the low temperature collection range; 114. Set the upper limit of the low temperature collection range; 206. Detector. Detailed Implementation

[0029] The embodiments of the present invention will now be described with reference to the accompanying drawings. It should be understood that the following embodiments are used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Where there is no conflict, the technical features in the following embodiments can be combined with each other.

[0030] Example 1 like Figure 1 As shown, the Stirling cryogenic modulation module 100 includes a module body 10, a metal modulation tube unit 20, a Stirling cryogenic refrigeration unit 30, a flexible heat conduction component 40, a direct contact rapid flash evaporation temperature control unit 50, a control interface unit 60, a signal level conversion unit 66, a timing mapping unit 70, a temperature feedback unit 80, and an elastic support component 90. The module body 10 is used to support or position the above components, and the module body 10 may include a base plate, a mounting plate, a bracket, a housing, or a mounting component adapted to the chromatography column oven.

[0031] The main body 10 of the module includes a mounting and positioning part 11. The mounting and positioning part 11 can be a positioning hole, a positioning groove, a connecting bracket, a pressure plate, a mounting surface, or a combination thereof. In the application of replacing the Peltier heat modulator, the mounting and positioning part 11 is adapted to the mounting hole position, mounting bracket, or mounting space of the original Peltier heat modulator in the full two-dimensional gas chromatography system 200, so that the Stirling cryogenic heat modulator module 100 can be installed in the original mounting position; the first chromatographic column connection interface 21 and the second chromatographic column connection interface 22 are adapted to the chromatographic column connection positions corresponding to the original heat modulator, thereby preserving the original connection relationship between the first chromatographic column 202 and the second chromatographic column 203.

[0032] like Figure 1 and Figure 3 As shown, the metal modulation tube unit 20 includes a first column connection interface 21, a second column connection interface 22, and a metal modulation tube body 23. The first column connection interface 21 is used to connect to the first column 202, the second column connection interface 22 is used to connect to the second column 203, and the metal modulation tube body 23 is connected between the first column connection interface 21 and the second column connection interface 22. The metal modulation tube body 23 is a thin-walled metal capillary, preferably a thin-walled stainless steel capillary, but nickel-based alloy capillary, titanium alloy capillary, or other metal capillary with an inert inner wall can also be used.

[0033] The outer diameter of the metal modulation tube body 23 is adapted to the outer diameter of the connection end of the first chromatographic column 202 and the second chromatographic column 203. Preferably, the first chromatographic column 202, the metal modulation tube body 23, and the second chromatographic column 203 are arranged along the same axis at the connection point, and the outer diameters of the connection ends of the three are the same or substantially the same. The difference lies in that the middle metal modulation tube body 23 is made of metal material for direct temperature control. Therefore, in the attached figures, the metal modulation tube body 23 and the two side chromatographic columns are represented by similar thicknesses to avoid the understanding that the metal modulation tube body 23 is a large independent heat exchanger much larger than the chromatographic column.

[0034] The inner diameter and length of the metal modulation tube body 23 can be determined according to the sample type, modulation cycle, carrier gas flow rate, and column specifications. For example, the inner diameter of the metal modulation tube body 23 can be from 0.25 mm to 2.0 mm, and the length can be from 5 mm to 50 mm. The inner wall of the metal modulation tube body 23 can be provided with an inert coating 24. The inert coating 24 can be a silanized coating, a diamond-like carbon coating, a ceramic inert layer, a noble metal protective layer, or other inert surfaces suitable for gas chromatography flow paths, to reduce the risk of sample components adsorbing, catalyzing, or decomposing with the tube wall under low temperature and rapid temperature rise conditions.

[0035] The Stirling cryogenic refrigeration unit 30 includes a cold head 31. The cold head 31 is used to output cryogenic cooling capacity. The Stirling cryogenic refrigeration unit 30 can be a free-piston Stirling refrigerator or other Stirling refrigeration device capable of providing cryogenic cooling capacity. Depending on the boiling point of the analyte, the carrier gas conditions, and the modulation cycle, the set cryogenic collection range of the metal modulation tube body 23 can be set to, for example, -150°C to -180°C, or other cryogenic ranges depending on the specific sample and system conditions.

[0036] A flexible heat conduction assembly 40 connects the cold head 31 to the metal modulating tube unit 20. The flexible heat conduction assembly 40 may include copper braided tape, flexible heat pipe, multi-strand soft copper tape, flexible heat-conducting sheet, flexible graphite heat-conducting sheet, or a heat-conducting assembly formed by combining a flexible heat-conducting component and a heat-conducting clamping block. One end of the flexible heat conduction assembly 40 is thermally connected to the cold head 31, and the other end is thermally connected to the outer wall of the metal modulating tube unit 20, the heat-conducting clamping part, or a position near the metal modulating tube body 23. The flexible heat conduction assembly 40 has a bending allowance, preventing a rigid mechanical connection between the cold head 31 and the metal modulating tube unit 20.

[0037] Through the aforementioned flexible cooling structure, the cooling energy generated by the cold head 31 can be transferred to the metal modulation tube body 23, while the mechanical vibration of the cold head 31 is not directly transmitted to the metal modulation tube body 23 and the two chromatographic columns along a rigid path. The flexible heat conduction component 40 can be thermally connected to the cold head 31 and the metal modulation tube unit 20 through screw clamping, thermally conductive clamping, low-temperature thermal grease, or metal clamping blocks. The above connection methods are used to improve heat conduction efficiency while allowing for slight relative displacement between the cold head 31 and the metal modulation tube unit 20.

[0038] like Figure 6 As shown, in a preferred embodiment, the Stirling cryogenic modulation module 100 further includes a cold zone insulation component 33. The cold zone insulation component 33 surrounds at least a portion of the outer side of the cold zone formed by the cold head 31, the flexible heat conduction component 40, and the low-temperature trapping section of the metal modulation tube body 23, so that when the cold energy output from the cold head 31 is transferred to the metal modulation tube body 23 through the flexible heat conduction component 40, the heat transfer from the external environment to the cold zone is suppressed.

[0039] The cold zone insulation component 33 can be an insulation layer, insulation cover, insulation shell, insulation cavity, or a combination thereof, and can be configured as an integral, split, or detachable structure depending on the module installation space. The cold zone insulation component 33 can be provided with channels or openings through which the drive wires of the first chromatographic column 202, the second chromatographic column 203, the direct contact rapid flash evaporation temperature control unit 50, and the lead wires of the temperature sensor 81 can pass; the provision of the channels or openings does not change the direct thermal contact relationship between the direct contact rapid flash evaporation temperature control unit 50 and the metal modulation tube body 23, and allows the metal modulation tube body 23 to perform rapid flash evaporation heating and cooling.

[0040] To clearly illustrate the internal connections between the cold head 31, the flexible heat conduction assembly 40, the metal modulation tube body 23, and the direct contact rapid flash evaporation temperature control unit 50 Figure 1 and Figure 3 The cold zone insulation component 33 is omitted in the middle. Figure 6 The diagram shows the fit relationship when the cold zone insulation component 33 is installed. The specific shape, thickness and material of the cold zone insulation component 33 can be determined according to the cooling load, installation space and maintenance requirements. Figure 6 The relative distances and proportions of the components are only for illustrative purposes. In actual installation, the direct contact rapid flash evaporation temperature control unit 50 and the metal modulation tube body 23 maintain the aforementioned direct thermal contact relationship.

[0041] The elastic support assembly 90 supports the metal modulation tube unit 20. The elastic support assembly 90 may include an elastic washer 91, a bellows 92, a vibration damping pad, an elastic clamp, a vibration isolation support 93, or an elastic suspension. The elastic support assembly 90 can be disposed between the metal modulation tube unit 20 and the module body 10, or between the metal modulation tube unit 20 and the inner wall of the column oven. The cold head 31 can be supported by an independent support structure 32, which is separate from the support path of the metal modulation tube unit 20. Thus, the metal modulation tube unit 20 remains stable relative to the column connection position, while reducing the vibration of the cold head 31 transmitted along the flexible heat conduction assembly 40, the module body 10, or the column interface to the first column 202 and the second column 203.

[0042] The direct-contact rapid flash evaporation temperature control unit 50 is in direct thermal contact with the metal modulation tube body 23. The direct-contact rapid flash evaporation temperature control unit 50 can be a thin metal resistive layer formed on the outer wall of the metal modulation tube body 23, a resistance heating element attached to the outer wall of the metal modulation tube body 23, a clamping heating block pressed or held against the outer wall of the metal modulation tube body 23, a sleeve-type heating block, a printed resistance track, or a combination thereof. Preferably, the direct-contact rapid flash evaporation temperature control unit 50 is attached or clamped along the axial direction of the metal modulation tube body 23 near the low-temperature trapping section, so that the metal modulation tube body 23 itself serves as the temperature-controlled low-heat-capacity modulation section.

[0043] Compared to indirect heating via a larger intermediate heat transfer structure, the direct contact rapid flash evaporation temperature control unit 50 directly inputs heat to the metal modulation tube body 23, reducing additional heat transfer links and additional heat capacity. Thus, during the low-temperature trapping stage, the metal modulation tube body 23 can maintain a low temperature through the Stirling cryogenic refrigeration unit 30 and the flexible heat conduction component 40; during the flash release stage, the metal modulation tube body 23 can rapidly heat up under the drive of the power drive circuit 65, causing the trapped components to rapidly vaporize and enter the second chromatographic column 203; after flash evaporation, the direct contact rapid flash evaporation temperature control unit 50 stops heating output, and the metal modulation tube body 23 is then cooled back down through the cold head 31 and the flexible heat conduction component 40.

[0044] The temperature feedback unit 80 includes a temperature sensor 81 and a controller 82. The temperature sensor 81 can be located on the outer wall of the metal modulation tube body 23, in the cooling clamp, or near the metal modulation tube body 23. The temperature sensor 81 can be a Pt100 temperature sensor, a thermocouple, a thin-film temperature sensor, or other temperature detection elements suitable for low-temperature and rapidly changing temperature environments. The controller 82 is connected to the temperature sensor 81 and adjusts the cooling power of the Stirling cryogenic refrigeration unit 30 and / or the temperature rise output of the direct contact rapid flash temperature control unit 50 according to the temperature of the metal modulation tube body 23 or the metal modulation tube unit 20. The controller 82 can also output a low-temperature stability signal, a recooling completion signal, an over-temperature signal, or an under-temperature signal to the timing mapping unit 70.

[0045] Example 2 like Figure 2 As shown, the control interface unit 60 includes a signal input terminal 61. The signal input terminal 61 is used to receive synchronization line signals, valve event signals, dry contact signals, TTL signals, relay output signals, or trigger signals converted via the communication interface from the gas chromatograph host 201. In applications replacing the Peltier thermal modulator, the signal input terminal 61 is connected to the control output terminal 204 of the gas chromatograph host 201, which was originally used to control the Peltier thermal modulator, allowing the gas chromatograph host 201 to continue using its original trigger output.

[0046] The signal level conversion unit 66 may include an isolation input circuit 62, a level conversion circuit 63, a pulse shaping circuit 64, and a power drive circuit 65. The isolation input circuit 62 may employ optocoupler isolation, relay isolation, or a digital isolator to reduce electrical interference between the gas chromatograph host 201 and the Stirling cryogenic modulation module 100. The level conversion circuit 63 converts low-voltage logic signals, passive contact signals, or relay signals into logic levels recognizable by the controller 82 or timing mapping unit 70. The pulse shaping circuit 64 identifies the trigger edge and limits the drive pulse width. The power drive circuit 65 outputs a controlled temperature rise drive signal to the direct-contact rapid flash evaporation temperature control unit 50.

[0047] The timing mapping unit 70 can be implemented by an MCU, FPGA, CPLD, comparator circuit, timer circuit, or state machine circuit. The timing mapping unit 70 includes a low-temperature stability judgment module 71, a flash evaporation trigger module 72, a recooling confirmation module 73, and an abnormal trigger shielding module 74. The low-temperature stability judgment module 71 receives the temperature information of the metal modulation tube output by the temperature feedback unit 80; when the metal modulation tube body 23 reaches the set low-temperature trapping range and maintains it for a preset time, the low-temperature stability judgment module 71 outputs an allow trigger signal. After receiving the allow trigger signal and the trigger signal after level conversion, the flash evaporation trigger module 72 drives the direct contact rapid flash evaporation temperature control unit 50 through the power drive circuit 65. The recooling confirmation module 73 monitors the temperature change of the metal modulation tube body 23 after flash evaporation to confirm whether it has recooled back to the set low-temperature trapping range. The abnormal trigger shielding module 74 disables, delays, or alarms the next trigger when there is no recooling, the temperature is too high, the temperature sensor is abnormal, the trigger signal interval is less than the set minimum time, the trigger pulse width exceeds the set range, or the trigger level exceeds the set range.

[0048] Through the aforementioned control structure, the gas chromatograph host 201 can continue to use the trigger output and modulation cycle parameters originally used for the Peltier thermal modulator. The Stirling cryogenic thermal modulation module 100 internally converts the original trigger cycle into an execution sequence suitable for Stirling cryogenic, direct flash heating and reflux confirmation, thereby reducing the need to modify the original gas chromatographic method files.

[0049] Example 3 like Figure 2 As shown, the all-two-dimensional gas chromatography system 200 includes a gas chromatograph main unit 201, a first column 202, a second column 203, and a Stirling cryogenic modulation module 100. During replacement installation, the gas chromatography system can be shut down first, and the column oven can be cooled to a suitable operating temperature; the control connection between the original Peltier modulator and the gas chromatograph main unit 201 can be disconnected; the connection between the original Peltier modulator and the first column 202 and the second column 203 can be disconnected; the original Peltier modulator can be removed; the Stirling cryogenic modulation module 100 can be installed in its original position; the first column 202 can be connected via the first column connection interface 21, and the second column 203 can be connected via the second column connection interface 22; the control output terminal 204 of the gas chromatograph main unit 201 can be connected to the signal input terminal 61 of the control interface unit 60. The outlet of the second column 203 is connected to a detector 206, which is used to detect the sample components separated by the second column 203.

[0050] After installation, the Stirling cryogenic cooling unit 30 is activated. The cold head 31 transfers cooling energy to the metal modulation tube body 23 via the flexible heat transfer component 40, causing the metal modulation tube body 23 to enter the set low-temperature trapping range. The temperature feedback unit 80 continuously monitors the temperature of the metal modulation tube body 23 or the metal modulation tube unit 20. Once the metal modulation tube body 23 reaches the set low-temperature trapping range and stabilizes, the timing mapping unit 70 allows rapid flash evaporation to be triggered.

[0051] like Figure 4 As shown, in one modulation cycle, the system first enters the cryogenic hold phase. Sample components flowing from the first chromatographic column 202 enter the metal modulation tube body 23, where the metal modulation tube body 23 performs cold capture and focusing of the sample components within a set low-temperature capture range. When the gas chromatograph host 201 outputs a trigger signal according to the original gas chromatographic method file, the control interface unit 60 receives the trigger signal. The signal level conversion unit 66 isolates, converts, and shapes the trigger signal's level. The timing mapping unit 70 determines whether triggering is allowed based on the temperature state of the metal modulation tube body 23.

[0052] Figure 4 In the process, modulation cycle 101 starts from cycle start point 112. The original trigger signal 102 is time-mapped to form timing-mapped output signal 103 and fast flash evaporation drive signal 104. The temperature curve 105 of the metal modulation tube corresponds sequentially to the cryogenic holding stage 106, the fast flash evaporation stage 107, the component release stage 108, the recooling stage 109, and the low-temperature ready stage 110. The refrigeration output status signal 111 is used to indicate the refrigeration output status of the Stirling cryogenic refrigeration unit 30. The setting of the lower limit of the low-temperature trapping range 113 and the setting of the upper limit of the low-temperature trapping range 114 are used to determine whether the metal modulation tube body 23 has reached the low-temperature stability or recooling completion state.

[0053] When triggering is permitted, the direct-contact rapid flash evaporation temperature control unit 50 rapidly heats the metal modulation tube body 23, causing the captured components to rapidly vaporize and enter the second chromatographic column 203 in a narrow band. After the flash evaporation heating is completed, the direct-contact rapid flash evaporation temperature control unit 50 stops the heating output, and the Stirling cryogenic refrigeration unit 30 cools the metal modulation tube body 23 back down via the flexible heat transfer component 40. After the back-cooling confirmation module 73 confirms that the metal modulation tube body 23 has returned to the set low-temperature capture range, it allows the next modulation cycle to be triggered; if the metal modulation tube body 23 has not yet returned to the set low-temperature capture range when the next trigger signal arrives, the abnormal trigger shielding module 74 prohibits or delays the trigger and may output an alarm signal.

[0054] During the above process, the connection relationship between the first chromatographic column 202 and the second chromatographic column 203 remains the same as the connection relationship corresponding to the original Peltier thermal modulator, and the gas chromatography host 201 can maintain the modulation cycle parameters in the original gas chromatography method file; thus, the Stirling deep cryogenic modulation module 100 can be used as a replacement and upgrade module in the existing full two-dimensional gas chromatography system.

[0055] like Figure 5 As shown, the Stirling cryogenic thermal modulation control method executes sequentially through the following stages: cryogenic holding stage 106, rapid flash evaporation stage 107, component release stage 108, recooling stage 109, and low-temperature ready stage 110. Temperature sensor 81 collects the temperature of the metal modulation tube body 23 or a location near it. Controller 82 adjusts the operating state of the Stirling cryogenic refrigeration unit 30 and / or the direct contact rapid flash evaporation temperature control unit 50 based on a comparison of the temperature with the set lower limit 113 and the set upper limit 114 of the low-temperature trapping range. It then outputs a low-temperature stabilization signal or a recooling completion signal to the timing mapping unit 70.

[0056] Example 4 In applications where the sample to be analyzed contains C2 to C6 light hydrocarbons or other low-boiling-point components, the low-temperature collection range of the metal modulation tube body 23 can be set to -150°C to -180°C to provide lower temperature collection conditions. The rapid flash evaporation stage can heat the metal modulation tube body 23 to a sample release state, allowing the collected components to be rapidly released into the second chromatographic column 203.

[0057] For samples containing components with a wide boiling point range, the timing mapping unit 70 can adjust the fast flash pulse width or the triggering conditions allowed for the next cycle based on the modulation cycle, the temperature of the metal modulation tube, and the recooling time. If high-boiling-point components require a higher final flash temperature or a longer heating time, the corresponding output can be set through the power drive circuit 65 and the controller 82. If low-boiling-point components require a longer cryogenic holding time, this can be achieved through the modulation cycle parameters of the original gas chromatography method file and the recooling confirmation logic within the module.

[0058] It should be noted that the above-described low-boiling-point component analysis scenario is used to illustrate the working conditions that this module can provide. The specific capture rate, peak area recovery rate, peak width, or detection limit can be determined experimentally based on the actual sample, chromatographic column, carrier gas, modulation cycle, and detector conditions. This specification does not limit the invention based on unverified specific experimental values.

[0059] Example 5 In other embodiments, the flexible heat conduction component 40 may adopt a multi-segment series flexible cooling structure, or a combination of a cooling block and a flexible connector may be provided between the cold head 31 and the metal modulation tube unit 20; the temperature feedback unit 80 may simultaneously detect the temperature of the cold head 31 and the temperature of the metal modulation tube body 23, and determine the cooling state of the flexible heat conduction component 40 based on the temperature difference between the two locations.

[0060] In other embodiments, the control interface unit 60 may be provided with multiple signal input terminals 61 to adapt to different output modes of the gas chromatograph host 201; for passive dry contact output, a logic trigger signal can be formed by a pull-up power supply and an isolation input circuit 62; for TTL signals, the level can be adjusted to a level that the controller 82 can recognize by a level conversion circuit 63; for relay output, a stable trigger pulse can be obtained by a debounce and pulse shaping circuit 64.

[0061] In other embodiments, the abnormal trigger shielding module 74 can also determine abnormalities based on the trigger signal interval, the slope of the temperature change of the metal modulation tube, the heating output status, or the temperature sensor status. For example, when the interval between consecutive trigger signals is less than the minimum time required for the metal modulation tube body 23 to complete the recooling, the abnormal trigger shielding module 74 can shield subsequent triggers or output alarms. When the temperature sensor 81 is open-circuited or short-circuited, the abnormal trigger shielding module 74 can prohibit the output of the direct contact rapid flash evaporation temperature control unit 50.

[0062] The above embodiments are only used to illustrate the technical solution of the present invention. For those skilled in the art, adjustments can be made to the specific form, connection method, and control parameters of each component without departing from the concept of the present invention, and all such adjustments should fall within the protection scope of the present invention.

Claims

1. A Stirling cryogenic thermal modulation module for replacing a Peltier thermal modulator, characterized in that, It includes a module body (10), a metal modulation tube unit (20), a Stirling cryogenic refrigeration unit (30), a flexible heat conduction component (40), a direct contact rapid flash temperature control unit (50), a control interface unit (60), a signal level conversion unit (66), a timing mapping unit (70), a temperature feedback unit (80), and an elastic support component (90). The module body (10) includes an installation positioning part (11), which is configured to be compatible with the mounting holes, mounting brackets or mounting space of the original Peltier heat modulator in the full two-dimensional gas chromatography system (200) so that the Stirling cryogenic heat modulator module (100) is installed at the mounting position of the original Peltier heat modulator. The metal modulation tube unit (20) has a first column connection interface (21), a second column connection interface (22), and a metal modulation tube body (23) connected between the first column connection interface (21) and the second column connection interface (22). The metal modulation tube body (23) serves as a low heat capacity temperature-controlled modulation section. The first column connection interface (21) is used to connect to the first column (202), and the second column connection interface (22) is used to connect to the second column (203). The Stirling cryogenic refrigeration unit (30) includes a cold head (31); The flexible heat conduction component (40) connects the cold head (31) and the metal modulation tube unit (20) to transfer the cold energy generated by the cold head (31) to the metal modulation tube body (23) and to form a non-rigid mechanical connection between the cold head (31) and the metal modulation tube unit (20). The elastic support assembly (90) is used to support the metal modulation tube unit (20) and reduce the mechanical vibration of the cold head (31) transmitted to the first chromatographic column (202) and the second chromatographic column (203); The direct contact rapid flash evaporation temperature control unit (50) is in direct thermal contact with the metal modulation tube body (23) and is used to directly control the rapid heating of the metal modulation tube body (23). The control interface unit (60) has a signal input terminal (61), which is matched with the signal type, level range and trigger logic of the control output terminal (204) of the gas chromatograph host (201) originally used to control the Peltier thermal modulator; The signal level conversion unit (66) is used to convert the trigger signal received by the signal input terminal (61) into the drive signal of the direct contact rapid flash temperature control unit (50); The timing mapping unit (70) is used to map the single modulation trigger timing of the original Peltier modulator to the cryogenic hold timing, rapid flash trigger timing, and recooling confirmation timing of the metal modulation tube body (23) while keeping the modulation cycle parameters in the original gas chromatography method file unchanged. The temperature feedback unit (80) is used to detect the temperature of the metal modulation tube body (23) or the metal modulation tube unit (20), and to prohibit or delay the next rapid flash evaporation trigger when the metal modulation tube body (23) has not cooled back to the set low temperature capture range.

2. A Stirling cryogenic thermal modulation module for replacing a Peltier thermal modulator according to claim 1, characterized in that, The installation positioning part (11) includes one or more of the following: positioning hole, positioning groove, connecting bracket, pressure plate or mounting surface; the first chromatographic column connection interface (21) and the second chromatographic column connection interface (22) are adapted to the chromatographic column connection positions corresponding to the original Peltier heat modulator, so as to retain the original connection relationship between the first chromatographic column (202) and the second chromatographic column (203) after the Stirling deep cryogenic modulation module (100) is installed.

3. A Stirling cryogenic thermal modulation module for replacing a Peltier thermal modulator according to claim 1, characterized in that, The outer diameter of the metal modulation tube body (23) is adapted to the outer diameter of the connection end of the first chromatographic column (202) and the second chromatographic column (203); the first chromatographic column (202), the metal modulation tube body (23) and the second chromatographic column (203) are arranged along the same axis at the connection and have the same or substantially the same outer diameter; the metal modulation tube body (23) is a thin-walled stainless steel capillary, a nickel-based alloy capillary, a titanium alloy capillary or a metal capillary with an inert inner wall, and the inner wall of the metal modulation tube body (23) is provided with an inert coating (24).

4. A Stirling cryogenic thermal modulation module for replacing a Peltier thermal modulator according to claim 1, characterized in that, The direct contact rapid flash evaporation temperature control unit (50) includes one or more of the following: a metal thin film resistance layer, a resistance heating element, a clamping heating block, a sleeve heating block, or a printed resistance track, formed on, attached to, pressed onto, or clamped on the outer wall of the metal modulation tube body (23); the direct contact rapid flash evaporation temperature control unit (50) is configured to directly input heat to the metal modulation tube body (23) after receiving the flash evaporation drive signal, so that the metal modulation tube body (23) rapidly heats up from a low temperature trapping state to a sample release state.

5. A Stirling cryogenic thermal modulation module for replacing a Peltier thermal modulator according to claim 1, characterized in that, The flexible heat conduction component (40) includes one or more of the following: copper braided strip, flexible heat pipe, multi-strand soft copper strip, flexible heat conduction sheet, flexible graphite heat conduction sheet, or a heat conduction component formed by combining a flexible heat conduction element and a heat conduction clamping block; one end of the flexible heat conduction component (40) is thermally connected to the cold head (31), and the other end is thermally connected to the outer wall of the metal modulation tube unit (20), the heat conduction clamping part, or the heat conduction area near the metal modulation tube body (23); the Stirling cryogenic heat modulation module also includes a cold zone insulation component (33), which surrounds at least part of the outside of the cold zone formed by the cold head (31), the flexible heat conduction component (40), and the low-temperature trapping section of the metal modulation tube body (23), for reducing the heat transfer from the external environment to the cold zone.

6. A Stirling cryogenic thermal modulation module for replacing a Peltier thermal modulator according to claim 1, characterized in that, The elastic support assembly (90) includes one or more of the following: elastic washer (91), bellows (92), vibration damping pad, elastic clamp, vibration isolation support (93), or elastic suspension; the cold head (31) is supported by an independent support structure (32), which is separate from the support path of the metal modulation tube unit (20).

7. A Stirling cryogenic thermal modulation module for replacing a Peltier thermal modulator according to claim 1, characterized in that, The temperature feedback unit (80) includes a temperature sensor (81) disposed on the metal modulation tube body (23), the cooling clamping part or near the metal modulation tube body (23) and a controller (82) connected to the temperature sensor (81); the controller (82) is used to adjust the cooling power of the Stirling cryogenic refrigeration unit (30) and / or the heating output of the direct contact rapid flash temperature control unit (50), and output a low temperature stability signal, a cooling return completion signal, an over-temperature signal or an under-temperature signal to the timing mapping unit (70).

8. A Stirling cryogenic thermal modulation module for replacing a Peltier thermal modulator according to claim 1, characterized in that, The signal input terminal (61) is configured to receive one or more of the following: a synchronization line signal, a valve event signal, a dry contact signal, a TTL signal, a relay output signal, or a trigger signal converted by a communication interface; the signal level conversion unit (66) includes an isolation input circuit (62), a level conversion circuit (63), a pulse shaping circuit (64), and a power drive circuit (65); the timing mapping unit (70) includes a low temperature stability judgment module (71), a flash evaporation trigger module (72), a recooling confirmation module (73), and an abnormal trigger shielding module (74), used to map the received single-modulation trigger signal to at least two execution states among cryogenic hold, flash evaporation heating, stop heating, recooling confirmation, and abnormal trigger shielding.

9. A Stirling deep cryogenic modulation control method based on the original Peltier thermal modulator control signal, characterized in that, While keeping the modulation cycle parameters unchanged in the original gas chromatography method file, the method, applied to the Stirling cryogenic modulation module according to any one of claims 1 to 8, comprises: The Stirling cryogenic modulation module (100) is installed in the original Peltier modulator installation position in the full two-dimensional gas chromatography system (200), and the metal modulation tube body (23) is connected between the first chromatographic column (202) and the second chromatographic column (203). The trigger signal originally used by the gas chromatograph host (201) to control the Peltier heat modulator is received through the control interface unit (60); The trigger signal is level-converted and pulse-shaped to obtain the drive signal of the direct contact rapid flash evaporation temperature control unit (50); During the capture phase of the modulation cycle, the metal modulation tube body (23) is kept within a set low temperature capture range by the cold head (31) of the Stirling cryogenic refrigeration unit (30) and the flexible heat conduction assembly (40). Upon receiving the trigger signal that meets the triggering conditions, the direct contact rapid flash temperature control unit (50) is driven to rapidly release the trapped components in the metal modulation tube body (23) and enter the second chromatographic column (203). After the flash evaporation is completed, the heating output is stopped, and the cooling process of the metal modulation tube body (23) is monitored by the temperature feedback unit (80). When the metal modulation tube body (23) fails to cool back to the set low temperature collection range, the next triggering is prohibited, delayed, or an alarm is triggered. Repeat the above steps according to the modulation cycle parameters in the original gas chromatography method file.

10. A fully two-dimensional gas chromatography system, characterized in that, The system includes a gas chromatograph host (201), a first chromatographic column (202), a second chromatographic column (203), and a Stirling cryogenic modulation module as described in any one of claims 1 to 8; the metal modulation tube body (23) is connected between the first chromatographic column (202) and the second chromatographic column (203); the control output terminal (204) of the gas chromatograph host (201), originally used to control the Peltier modulator, is connected to the signal input terminal (61) of the control interface unit (60); the gas chromatograph host (201) is configured to call the gas chromatographic method file corresponding to the original Peltier modulator; the time mapping unit (70) controls the Stirling cryogenic modulation module (100) to perform cryogenic hold, rapid flash evaporation trigger, and recooling confirmation while maintaining the modulation cycle parameters in the gas chromatographic method file.

Images