A fault diagnosis analysis method and system for a chromatograph

Abstract

This invention discloses a fault diagnosis and analysis method and system for chromatographs, relating to the field of chromatograph fault diagnosis technology. The method includes the following steps: establishing a dynamic mapping model of the gas thermal field based on real-time temperature distribution information inside the chromatograph's detection cell; generating a temperature gradient distribution map within the detection cell through continuous acquisition by distributed multi-point temperature sensing units; and applying a controllable micro-amplitude pulsating airflow in the inlet path of the detection cell based on the temperature gradient distribution map output by the dynamic mapping model. By adjusting the pulsation frequency and amplitude, the gas flow state is disturbed, creating a diffusible gas disturbance zone inside the detection cell. This invention achieves temperature and flow field equilibrium in the detection cell through thermal field mapping and gas disturbance control, eliminating thermal stratification and retention effects, and restoring the linear relationship of the detection response. Furthermore, it dynamically corrects the time reference through a signal drift self-suppression mechanism, ensuring complete output of low-concentration signals, thereby improving the sensitivity, stability, and quantitative accuracy of the chromatograph.

Description

Technical Field

[0001] This invention relates to the field of chromatograph fault diagnosis technology, and specifically to a fault diagnosis analysis method and system for chromatographs. Background Technology

[0002] Fault diagnosis and analysis of a chromatograph refers to the systematic investigation and performance evaluation of key components such as the instrument's hardware, gas path, flow path, detector, electronic control system, and data acquisition module during operation, when phenomena such as abnormal peak shape, baseline drift, decreased sensitivity, unstable retention time, or abnormal pressure occur. This process aims to identify the root cause of the abnormality. This typically includes collecting operating parameters, analyzing chromatogram data characteristics, comparing with standard working curves, checking the sealing of tubing, verifying carrier gas purity and flow stability, evaluating detector response linearity, and verifying the stability of the injection and temperature control systems. By comprehensively assessing the operational status of each component, specific fault types such as gas path leaks, detector contamination, column temperature drift, and electronic circuit interference can be quickly identified. Based on this, corresponding repair and calibration measures can be developed to ensure the chromatograph returns to optimal analytical performance and quantitative accuracy.

[0003] The existing technology has the following shortcomings:

[0004] During long-term operation of the chromatograph, uneven heating of the gas inside the detection cell can easily create minute temperature gradients in the vertical direction, causing stratified gas density distribution and resulting in a hidden retention layer structure within the detection cell. This retention layer leads to slight differences in the migration velocity of gas molecules at different levels, causing local delays in the spatial transport of gas components. As the thickness of the retention layer dynamically changes, the linear relationship between the response time and amplitude of the detection signal is lost, exhibiting nonlinear drift in the detection response. When low-concentration components pass through the detection area, their signal peak is weakened by the combined effects of hysteresis and dilution. The system is prone to misinterpreting the true weak signal as baseline noise, resulting in decreased detection sensitivity and accumulation of quantitative errors, severely affecting the accuracy of trace component identification and analytical stability.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a fault diagnosis and analysis method and system for chromatographs to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a fault diagnosis and analysis method for a chromatograph, comprising the following steps:

[0008] Step 1: Based on the real-time temperature distribution information inside the chromatograph detection cell, a dynamic mapping model of the gas thermal field is established. The temperature gradient distribution map inside the detection cell is generated by continuous acquisition through distributed multi-point temperature sensing units. This map is used to characterize the thermal stratification state of the gas in the vertical direction and to provide thermal distribution benchmark data for subsequent gas flow control.

[0009] Step 2: Based on the temperature gradient distribution map output by the gas thermal field dynamic mapping model, a controllable micro-amplitude pulsating airflow is applied in the air inlet path of the detection cell. By adjusting the pulsation frequency and amplitude, the gas flow state is disturbed to break the local gas thermal stratification caused by the temperature gradient, so as to form a diffusible gas disturbance zone inside the detection cell, providing dynamic disturbance conditions for subsequent gas mixing and redistribution.

[0010] Step 3: Based on the flow characteristics of the gas disturbance zone, a gas redistribution process is constructed. In this process, the periodic oscillation of the inlet pressure is used to drive the continuous mixing of gases in different density layers, so that the gas migration path in the detection cell cavity is kept in dynamic equilibrium, thereby inhibiting the formation and accumulation of interlayer retention structures from the source.

[0011] Step 4: After the gas redistribution process is completed, implement temperature-controlled convection balance regulation. By alternating fine-tuning the heating and cooling stages of the detection cell, stabilize the direction of gas heat flow, further balance the temperature field distribution and gas transport rate inside the detection cell, and maintain the continuous consistency of gas flow in the detection area.

[0012] Step 5: Based on the stable gas transport state obtained after convection balance regulation, establish a signal drift self-suppression mechanism. Dynamically correct the time reference of the detection signal according to the real-time change of the gas transport rate, and actively compensate for the nonlinear drift of the detection response, thereby ensuring the complete acquisition and quantitative output accuracy of low concentration component signals.

[0013] Preferably, the steps for establishing a dynamic mapping model of the gas thermal field include:

[0014] Several temperature sensing units are installed at different heights and orientations in the detection pool cavity. The temperature sensing units are arranged at equal intervals from bottom to top along the axial direction of the detection pool and set at multiple angular positions in the radial direction to continuously collect temperature data inside the detection pool.

[0015] The temperature data collected by the temperature sensing unit is processed to correspond to time series and spatial location, and supplemented by interpolation of temperature difference between adjacent measuring points to form a temperature information set with temporal continuity and spatial integrity.

[0016] Based on the geometric dimensions, gas inlet location, gas outlet direction, and internal structural features of the detection cell, the temperature information set is spatially located, and a dynamic mapping model of the gas thermal field is established to determine the thermal stratification state of the gas inside the detection cell in the vertical direction.

[0017] Temperature gradient distribution map is generated using temperature data output from the gas thermal field dynamic mapping model. The spatial coordinates of the detection cell are used as the horizontal and vertical axes, and the temperature difference is used as the color change index. This map is used to characterize the thermal stratification distribution of the gas in the detection cell and to provide thermal distribution benchmark data for subsequent gas flow control.

[0018] Preferably, during the generation of the temperature gradient distribution map, the sampling frequency of the temperature sensing unit remains consistent, and the temperature data is integrated sequentially according to the acquisition time sequence, so that each time segment corresponds to a complete gas thermal field state. By continuously generating the temperature gradient distribution map, the dynamic changes of the temperature field in the detection cell are reflected in real time, so as to identify the formation area of ​​gas thermal stratification and provide a reference for adjusting the gas disturbance frequency.

[0019] Preferably, the step of applying a controllable micro-amplitude pulsating airflow in the air intake path of the detection cell includes:

[0020] A gas input end, a regulating chamber, and an airflow control valve are set at the air intake path of the detection cell. The airflow control valve is connected to the gas source through a high-temperature resistant flexible material, and the gas flow rate is periodically opened and closed through a precision drive unit to form a continuous micro-airflow pulsation before the gas enters the detection cell.

[0021] Based on the temperature gradient distribution map output by the gas thermal field dynamic mapping model, the propagation direction, frequency and amplitude of the pulsation are adjusted so that the airflow disturbance is concentrated on the area with a large temperature difference, so as to break the thermal stratification formed by the temperature gradient in the detection cell.

[0022] By continuously fine-tuning the pulsation parameters of the airflow, the gas disturbance zone expands along the axial direction of the detection cell and forms a periodically fluctuating disturbance wave, thereby causing the gas in the detection cell to generate coupled vibration in the vertical direction.

[0023] By maintaining the periodic input of pulsating airflow, a continuous micro-perturbation equilibrium state is formed inside the detection cell. The gas dynamically exchanges energy and momentum between perturbation and recovery, thereby maintaining the homogenization of the gas thermal field and providing continuous perturbation conditions for subsequent gas mixing and redistribution.

[0024] Preferably, the adjustment range of the pulsation frequency and amplitude of the airflow control valve is adaptively set according to the magnitude of the temperature difference in the temperature gradient distribution diagram. When the temperature difference in the detection cell increases, the pulsation frequency and airflow amplitude are increased to enhance the disturbance effect on the thermal stratification area; when the temperature difference decreases, the pulsation frequency and airflow amplitude are decreased to maintain the stable diffusion state of the gas disturbance zone inside the detection cell.

[0025] Preferably, the steps for constructing the gas redistribution process include:

[0026] Controlled pressure periodic oscillations are introduced at the air intake path of the detection pool. The pressure periodic oscillations are achieved through the cooperation of the pressure stabilizing component at the air supply end and the air intake control valve, so that the gas inside the detection pool exhibits periodic pressure fluctuations in the time dimension and is coupled with the gas disturbance zone.

[0027] Pressure fluctuations are used to drive the periodic compression and expansion of gases in different density layers within the detection cell, causing volume flow between gas layers, thereby promoting continuous mixing of gases in different density layers and redistribution in the vertical direction;

[0028] By adjusting the duration and frequency of pressure oscillation, the flow cycle between gas layers and the residence time of gas in the detection cell are coordinated, which promotes the formation of a spiral circulation path of gas in the vertical and radial directions, so as to homogenize the gas density distribution and temperature gradient.

[0029] By maintaining the periodic oscillation of the intake pressure, the gas flow state in the detection cell is continuously kept between dynamic and equilibrium, thereby achieving full mixing throughout the entire cavity and inhibiting the formation and accumulation of interlayer retention structures at the source.

[0030] Preferably, the frequency of the pressure periodic oscillation is set to match the natural response frequency of the gas disturbance zone in the detection pool, and the pressure fluctuation amplitude is controlled within a range that does not affect the overall flow field stability of the detection pool, so that gases of different density layers form a continuous and uniform mixed flow under the action of periodic oscillation, thereby further improving the stability of gas redistribution and the balance and consistency of gas migration paths in the detection pool.

[0031] Preferably, the steps for implementing temperature-controlled convection balance regulation include:

[0032] Heating and cooling units are set up around the detection pool. The heating unit uses a high-temperature resistance wire winding structure to uniformly heat the detection pool wall, while the cooling unit cools the pool by circulating cooling medium. The alternating operation of the two units creates temperature-driven gas convection inside the detection pool.

[0033] By gradually adjusting the heating power and the flow rate of the cooling medium, the temperature of the detection pool wall changes periodically within a small range, causing an upward airflow to be generated during the heating stage and a downward airflow to be formed during the cooling stage, thereby establishing a closed-loop convection path in the vertical direction.

[0034] Adjust the time ratio of heating and cooling stages according to the changes in gas flow state, extend the heating or cooling duration to balance heat distribution, and keep the gas flowing continuously during the rising and reflux process to achieve heat exchange.

[0035] By maintaining alternating fine-tuning between heating and cooling phases, a stable convective equilibrium structure is formed inside the detection cell, which in turn allows the gas to be transported at an approximately uniform speed throughout the detection area, thereby maintaining the dynamic balance of the temperature field and the consistency of the gas flow direction.

[0036] Preferably, the steps for establishing a signal drift self-suppression mechanism include:

[0037] After completing the convection balance control and obtaining a stable gas transmission state, gas characteristic detection points at the inlet and outlet of the detection cell are selected, and the transmission time difference between the two detection points is measured to obtain the gas transmission rate change trend in real time, and the transmission rate is used as a time reference correction parameter.

[0038] Based on the real-time changes in gas transmission rate, the time reference of the detection response is dynamically matched through the synchronous trigger control of the detection signal acquisition device, so that the signal acquisition is synchronized with the actual gas transmission, thereby avoiding the accumulation of signal drift.

[0039] Based on the trend of gas transmission rate change, the amplitude and time correspondence of the detection signal are dynamically coordinated. By correcting the peak output time of the signal, active compensation for nonlinear drift of the detection response is achieved.

[0040] During the continuous operation of the signal drift suppression mechanism, the output timing and amplitude relationship of the detection signal are automatically adjusted according to the change in gas transmission rate, so that the low concentration component signal is fully acquired, thereby improving the temporal consistency and quantitative accuracy of the detection signal.

[0041] A fault diagnosis and analysis system for a chromatograph includes a gas thermal field mapping module, a gas disturbance generation module, a gas redistribution control module, a convection balance control module, and a signal drift self-suppression module.

[0042] Gas thermal field mapping module: Based on the real-time temperature distribution information inside the chromatograph detection cell, a dynamic mapping model of the gas thermal field is established, and a temperature gradient distribution map inside the detection cell is generated through continuous acquisition by distributed multi-point temperature sensing units.

[0043] Gas disturbance formation module: Based on the temperature gradient distribution map output by the gas thermal field dynamic mapping model, a controllable micro-amplitude pulsating airflow is applied in the air intake path of the detection cell. By adjusting the pulsation frequency and amplitude, the gas flow state is disturbed, so that a diffusible gas disturbance zone is formed inside the detection cell.

[0044] Gas redistribution control module: Based on the flow characteristics of the gas disturbance zone, a gas redistribution process is constructed. In this process, the periodic oscillation of the inlet pressure is used to drive the continuous mixing of gases of different density layers, so that the gas migration path in the detection cell cavity is kept in dynamic equilibrium.

[0045] Convection balance control module: After the gas redistribution process is completed, temperature-controlled convection balance regulation is implemented. By alternating fine-tuning the heating and cooling stages of the detection cell, the direction of gas heat flow is stabilized, and the temperature field distribution and gas transport rate inside the detection cell are balanced.

[0046] Signal drift self-suppression module: Based on the stable gas transmission state obtained after convection balance control, a signal drift self-suppression mechanism is established. The time reference of the detection signal is dynamically corrected according to the real-time change of the gas transmission rate, and the nonlinear drift of the detection response is actively compensated.

[0047] The technical effects and advantages provided by the present invention in the above technical solution are as follows:

[0048] This invention establishes a dynamic mapping model of the gas thermal field within the detection cell and implements pulsating airflow disturbance and pressure oscillation control, thereby making the temperature and density distribution of the gas within the detection cell more uniform and eliminating thermal stratification and stagnant layer structures caused by uneven heating. During gas flow, continuous convective exchange is maintained, allowing heat to be transferred evenly within the detection area, thus ensuring a stable and consistent gas transport path within the detection cell. This process effectively avoids signal delay and peak distortion caused by local gas stagnation, restoring a linear correspondence between detection response time and amplitude, and improving the stability and repeatability of the detection system.

[0049] This invention establishes a signal drift self-suppression mechanism after convection balance control, enabling the detection signal to adjust the time reference in real time according to the dynamic changes in gas transport rate, automatically offsetting nonlinear drift. This self-suppression process maintains the complete output of low-concentration component signals, preventing weak signals from being weakened or misinterpreted as noise due to gas flow rate fluctuations during detection. This improves detection sensitivity and quantitative accuracy, allowing the chromatograph to maintain stable analytical performance and highly reliable trace component identification capabilities even under long-term operating conditions. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0051] Figure 1 This is a flowchart of a fault diagnosis and analysis method for a chromatograph according to the present invention.

[0052] Figure 2 This is a schematic diagram of a fault diagnosis and analysis system for a chromatograph according to the present invention. Detailed Implementation

[0053] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art.

[0054] This invention provides, for example Figure 1 The method for fault diagnosis and analysis of a chromatograph, as shown, includes the following steps:

[0055] Step 1: Based on the real-time temperature distribution information inside the chromatograph detection cell, a dynamic mapping model of the gas thermal field is established. The temperature gradient distribution map inside the detection cell is generated by continuous acquisition through distributed multi-point temperature sensing units. This map is used to characterize the thermal stratification state of the gas in the vertical direction and to provide thermal distribution benchmark data for subsequent gas flow control.

[0056] The specific implementation method for this step is as follows:

[0057] During the preparation phase of the chromatograph, several temperature sensing units are precisely installed at different heights and orientations within the detection cell to comprehensively acquire temperature distribution information. Each temperature sensing unit employs a high-sensitivity thermistor, with its probe end fixed to the cell wall via a high-temperature resistant sealing material, ensuring full contact between the measurement point and the gas inside the cell. The sensing units are arranged at equal intervals from bottom to top along the axial direction of the detection cell to reflect the temperature distribution differences of the gas in the vertical direction. Simultaneously, multiple sensing units are embedded at various angular positions in the radial direction of the detection cell to monitor temperature changes in different horizontal regions at the same height. To prevent interference from external heat sources or airflow, a thermally insulating ceramic sleeve is wrapped around the contact area between the sensing unit and the outer casing, ensuring that external temperature fluctuations do not affect the internal measurement results. All temperature sensing units are connected to the data acquisition port via shielded cables and a uniform sampling frequency is set to ensure that temperature data from different locations are recorded synchronously at the same time reference. Before the test begins, the temperature sensing unit is powered on and preheated to bring the probe to a stable state similar to the operating temperature inside the test cell, thereby ensuring the response accuracy and consistency of the temperature acquisition process.

[0058] After the temperature sensing units are installed and initially collected, continuous recording of temperature changes in the detection pool during operation begins. Each temperature sensing unit outputs collected temperature data at fixed time intervals, and the temperature values ​​at all collection points are numbered according to the spatial coordinates of the detection pool for easy data correlation later. As the gas inside the detection pool flows and heats, the sensing units reflect the temperature change trend at different locations in real time. During the acquisition process, to reduce fluctuation errors caused by instantaneous airflow disturbances, the average of multiple samples is taken for each measurement to obtain a smoother temperature change curve. After the temperature data from all sensing units has been continuously recorded for a period of time, the time series is mapped to spatial locations to form a complete temperature information set. To make the spatial distribution more consistent, the temperature difference between adjacent measuring points is interpolated to supplement the data, making the temperature change of the gas inside the detection pool appear to be continuously changing in space. In this way, the temperature distribution trend can be made more consistent with the actual heat transfer characteristics of the gas without compromising the authenticity of the original data. The temperature data obtained at this stage includes not only the absolute temperature value at each location but also the rate of temperature change over time, providing fundamental data with temporal continuity and spatial integrity for the subsequent establishment of a dynamic mapping model of the gas thermal field.

[0059] After completing the spatiotemporal integration of temperature data, a dynamic mapping model of the gas thermal field is established based on the geometric dimensions of the detection pool, the gas inlet location, the gas outlet direction, and the internal structural characteristics. This model spatially locates the distribution coordinates of the temperature sensing units with the corresponding temperature acquisition data, dividing the detection pool cavity into several temperature analysis intervals. The temperature distribution of each interval is determined by the combined measurements of the surrounding sensing units. In the vertical direction, the temperature gradient trend is calculated through the temperature difference between adjacent measuring points, thus determining the gas's thermal stratification state in the vertical direction. In the horizontal direction, the heat transfer uniformity of the gas in the radial direction is analyzed through the temperature difference at different locations at the same height. The establishment process of the dynamic mapping model of the gas thermal field includes three parts: spatial registration of data, time series sorting, and temperature gradient trend analysis, ultimately achieving a dynamic correspondence between the temperature changes inside the detection pool in time and space. The model allows for real-time acquisition of the heat flow direction and temperature stratification degree of the gas within the detection pool, revealing local temperature difference regions caused by uneven gas heating. This model not only reflects the temperature distribution of the detection pool at a certain moment but also presents the gradual change of temperature during the heating process through time series correlation, enabling dynamic tracking of the thermal state of the gas within the detection pool.

[0060] After the dynamic mapping model of the gas thermal field is established, a temperature gradient distribution map inside the detection pool is generated using the temperature data output by the model. The temperature gradient distribution map uses the spatial coordinates of the detection pool as the horizontal and vertical axes, and the temperature difference as an indicator of color or brightness change, visually creating a clear stratification of the thermal distribution within the detection pool. Each temperature gradient distribution map corresponds to the gas thermal field state for a specific time segment; continuously generated distribution maps can reflect the trajectory of temperature field changes within the detection pool during its operating cycle. Based on the color distribution or brightness differences in different regions of the distribution map, areas with higher and relatively lower gas heating intensity can be clearly distinguished. When the temperature change trend of a certain local area shows a stable difference and a significant temperature difference with the surrounding areas, it can be determined that gas thermal stratification may exist in that area. By continuously generating temperature gradient distribution maps and recording the change process, the thickness and rate of change of the thermal stratification formed by the gas in the vertical direction inside the detection pool can be visually observed. The generation results of this distribution map serve as an important basis for subsequent gas flow control, providing fundamental conditions for determining the gas disturbance frequency, adjusting the inlet gas flow rate, and implementing pressure oscillations. At this stage, the temperature gradient distribution map not only reflects the existence of gas thermal stratification but also identifies the potential impact of uneven heat distribution on the monitoring signal response. By continuously generating and updating the temperature gradient distribution map, the temperature change state inside the detection cell can be monitored in real time, allowing for effective control of gas flow uniformity in subsequent operations. This provides reliable temperature reference information for the chromatograph during fault diagnosis and analysis, ensuring the stability of the gas transmission path inside the detection cell and the consistency of the detection signal's time response.

[0061] Through the implementation of the above-mentioned continuous steps, the temperature changes in different spatial regions inside the detection pool can be accurately collected, continuously recorded, dynamically modeled, and graphically represented, ultimately forming a temperature gradient distribution map that reflects the thermal stratification characteristics of the gas, laying the foundation for the dynamic control of gas flow.

[0062] Step 2: Based on the temperature gradient distribution map output by the gas thermal field dynamic mapping model, a controllable micro-amplitude pulsating airflow is applied in the air inlet path of the detection cell. By adjusting the pulsation frequency and amplitude, the gas flow state is disturbed to break the local gas thermal stratification caused by the temperature gradient, so as to form a diffusible gas disturbance zone inside the detection cell, providing dynamic disturbance conditions for subsequent gas mixing and redistribution.

[0063] The specific implementation method for this step is as follows:

[0064] After establishing the dynamic mapping model of the gas thermal field and obtaining the temperature gradient distribution map inside the detection pool, the main areas of thermal stratification and vertical locations with large temperature differences within the detection pool are identified based on the temperature change trends in each region of the temperature gradient distribution map. To create effective disturbances in these areas, a controllable gas pulsation structure is installed at the gas inlet path of the detection pool. This structure consists of a gas input end, a regulating chamber, and a gas flow control valve. The connecting pipe between the control valve and the gas source is made of a high-temperature resistant flexible material to adapt to the periodic changes in gas flow rate. The control valve, through a precision drive unit, periodically opens and closes the gas flow rate, thus creating continuous micro-amplitude gas flow pulsations before entering the detection pool. Each pulsation cycle includes a gas acceleration phase and a deceleration phase, during which the gas pressure and flow rate fluctuate slightly. By controlling the frequency, amplitude, and duration of the pulsations, the gas entering the detection pool exhibits a continuously fluctuating flow state over time. This step introduces micro-disturbances into the originally relatively stable gas flow within the detection pool, creating initial disturbance conditions for breaking the gas thermal stratification caused by the temperature gradient.

[0065] After gas pulsations are introduced into the detection pool, the temperature gradient distribution map output from the gas thermal field dynamic mapping model is used, combined with the spatial structure of the detection pool, to select the optimal propagation direction and frequency matching range of the pulsations. This allows the airflow disturbance to concentrate on areas with large temperature differences. After the gas pulsations enter the detection pool through the inlet path, their velocity changes are transmitted spatially, causing the gas within the detection pool to undergo periodic compression and expansion processes. Due to uneven heating of the gas within the detection pool, there are differences in gas density at different levels. When the pulsating airflow passes through, local shear flow occurs between levels with large density differences, disturbing the originally stable thermal stratification boundaries. This disturbance induces local vortex motion in the gas within the thermal stratification zone, redistributing heat between different gas layers and thus weakening the temperature gradient differences between layers. By continuously applying pulsating airflow, the gas inside the detection pool is kept in a non-static state. The stable stratification structure originally formed by the temperature gradient is gradually broken, and the gas within the detection pool changes from a static laminar flow state to a slightly turbulent state. The core of this stage lies in precisely controlling the pulsation frequency and airflow intensity so that the disturbance effect can effectively act on the thermal stratification region without disrupting the overall flow direction and detection stability of the gas in the detection cell.

[0066] After the gas thermal stratification is initially broken by the pulsating airflow, the pulsation parameters of the airflow are continuously fine-tuned to enable the gas disturbance zone to form a continuously diffusing dynamic structure within the detection cell. Based on the real-time changes in the temperature gradient distribution map, the range of pulsation frequency and the amplitude of the gas flow velocity are gradually adjusted, allowing the gas disturbance to propagate into the deeper regions of the detection cell over time. During this process, the gas forms periodically fluctuating disturbance waves within the detection cell, which gradually expand along the axial direction of the detection cell, causing coupled vibrations at different height levels. As the disturbance energy diffuses, the locally stagnant gas regions formed due to temperature gradient differences are reactivated, and the migration paths of gas molecules in the vertical direction become more uniform. Under continuous action, the gas disturbance zone exhibits dynamic diffusion characteristics, its boundaries constantly adjusting with airflow changes, bringing the gas flow state within the entire detection cell towards equilibrium. In this stage, through the continuous action of gas pulsation, the temperature field distribution within the detection cell gradually transitions from a multi-layered, uneven state to a relatively smooth thermal distribution state, thereby making the gas flow environment within the detection cell more stable.

[0067] After the gas disturbance zone forms and reaches a stable diffusion state, a periodic input of micro-pulsating airflow continues, allowing the gas inside the detection cell to achieve a dynamic equilibrium between disturbance and recovery. At this point, the gas flow within the detection cell exhibits a continuously slightly disturbed equilibrium state, effectively breaking down gas thermal stratification without causing large-scale disturbances in the gas flow field. In this way, the gas at different levels within the detection cell continuously exchanges energy and momentum, further weakening the temperature gradient and homogenizing the gas thermal field. The gas disturbance zone remains stable within the detection cell, ensuring good diffusion and controllability of the gas flow. Thus, the gas within the detection cell maintains a dynamically balanced flow state throughout the entire operation, providing continuous disturbance conditions for subsequent gas mixing and redistribution. When the detection cell re-enters the steady-state detection phase, the gas thermal stratification effect has been fully suppressed, and the gas transport rate tends to be uniform in all directions, laying the foundation for the time response stability of the detection signal.

[0068] By implementing the above steps, the temperature gradient distribution map output by the gas thermal field dynamic mapping model guides the application of gas flow pulsation, creating a gas disturbance zone with diffusion characteristics inside the detection cell. The formation and continuous action of this disturbance zone effectively eliminates the thermal stratification phenomenon caused by the temperature gradient, maintaining a dynamic equilibrium in the gas flow within the detection cell. This creates favorable conditions for subsequent gas mixing and redistribution, ensuring the uniformity of the gas transport path and the stability of the detection response during the fault diagnosis and analysis of the chromatograph.

[0069] Step 3: Based on the flow characteristics of the gas disturbance zone, a gas redistribution process is constructed. In this process, the periodic oscillation of the inlet pressure is used to drive the continuous mixing of gases in different density layers, so that the gas migration path in the detection cell cavity is kept in dynamic equilibrium, thereby inhibiting the formation and accumulation of interlayer retention structures from the source.

[0070] The specific implementation method for this step is as follows:

[0071] After a diffusible gas disturbance zone is formed inside the detection pool, controlled periodic pressure oscillations are introduced at the inlet path to further eliminate residual thermal stratification effects at different altitudes. These pressure oscillations are achieved by adjusting the coordination between a pressure stabilizing component at the gas supply end and an inlet control valve. The pressure stabilizing component ensures stable average gas pressure, while the inlet control valve periodically opens and closes to alter the instantaneous airflow resistance of the inlet channel, resulting in periodic pressure fluctuations in the gas within the detection pool over time. These pressure fluctuations gradually propagate along the inlet direction to the depths of the detection pool, coupling with the previously formed gas disturbance zone and causing periodic compression and expansion of the gas within that zone. Because different density layers respond differently to pressure changes, the periodic oscillations create alternating volumetric flows between gas layers, promoting continuous mixing of gases of different densities. The key at this stage is controlling the period and amplitude of the pressure oscillations to maintain a controllable balance between disturbance and recovery in the gas flow state, establishing a dynamic foundation for the subsequent continuous mixing process.

[0072] After the gas inside the detection cell is subjected to periodic pressure fluctuations, the flow characteristics of the gas disturbance zone begin to undergo structural changes. With continuous pressure oscillations, the originally layered temperature distribution regions within the detection cell cavity are gradually dispersed by the gas flow. Low-density gas in the high-temperature region is compressed downwards as pressure increases, while high-density gas in the low-temperature region is propelled upwards as pressure decreases, thus creating alternating gas exchange motion in the vertical direction. Each pressure oscillation causes relative displacement between different gas layers, allowing heat and momentum to be continuously transferred between layers, forming a cyclical mixing flow pattern. Because the period of pressure fluctuations is much shorter than the overall residence time of the gas within the detection cell, the gas achieves thorough vertical mixing under the alternating action of multiple cycles. Simultaneously, the boundary of the disturbance zone continuously expands during the mixing process, and the gas disturbance, originally limited to a local area, gradually covers the entire detection cell cavity, expanding the range of gas flow from local disturbance to full-cavity circulation. This stage of the mixing process is mainly characterized by relative flow between gas layers, enabling continuous redistribution of gas in the vertical direction, thereby weakening the influence of the temperature gradient on the flow path.

[0073] As the mixing motion between gas layers gradually intensifies, the temporal characteristics of the pressure oscillation are progressively adjusted to ensure a more stable and wider-coverage mixing effect. Based on the changing trend of temperature distribution within the detection pool, the duration of the pressure oscillation is appropriately extended, and the oscillation frequency is adjusted within a certain range to coordinate the interaction period between gas layers with the residence time of the gas in the detection pool. This time adjustment allows for effective exchange of gas flows between different layers during each pressure fluctuation. As the gas undergoes continuous pressure compression and release during its ascent and descent, its flow trajectory forms a spiral circulation path within the detection pool. This path causes disturbances in both the vertical and radial directions, thus promoting a more uniform gas density distribution throughout the detection pool. With increasing cycles, the temperature difference of the gas gradually decreases, the original thermal stratification boundaries are completely broken, and the migration path of the gas within the detection pool becomes continuous and balanced. The continuous gas redistribution process creates a dynamic flow structure within the detection pool, maintaining relative motion in different directions without disrupting the overall flow field stability.

[0074] After a stable gas redistribution state is established within the detection cell, a moderate periodic oscillation of the inlet pressure is maintained, ensuring the gas flow remains between dynamic and equilibrium. At this point, the gas within the detection cell exhibits a uniform density distribution, the temperature gradient is effectively weakened, and heat is uniformly transferred throughout the cavity via convection and diffusion. The gas flow driven by periodic oscillation maintains a stable mixing frequency, continuously correcting local unevenness caused by environmental changes or gas source fluctuations during operation. The gas migration path within the detection cell exhibits a periodic, stable reciprocating flow under this dynamic equilibrium state, with the gas trajectory covering the entire detection area, ensuring the gas within the detection cell remains fully mixed. As the gas redistribution process continues, the heat distribution and flow characteristics within the detection cell tend to become homogenized, thereby suppressing the re-formation and accumulation of interlayer stagnant structures at the source. Based on this, the gas transmission environment of the detection cell remains stable over a long period, preventing the detection signal from being affected by local gas stagnation or differences in migration speed during acquisition.

[0075] By implementing the above steps, the periodic oscillation of the inlet pressure drives the continuous mixing of gases of different density layers inside the detection cell, enabling dynamic redistribution of the gas migration paths within the detection cell cavity. This process effectively breaks down the stagnant structures formed between gas layers due to temperature differences, transforming the gas flow state inside the detection cell from static laminar flow to stable dynamic equilibrium flow, thus providing a uniform gas environment for subsequent temperature-controlled convection balance regulation.

[0076] Step 4: After the gas redistribution process is completed, implement temperature-controlled convection balance regulation. By alternating fine-tuning the heating and cooling stages of the detection cell, stabilize the direction of gas heat flow, further balance the temperature field distribution and gas transport rate inside the detection cell, and maintain the continuous consistency of gas flow in the detection area.

[0077] The specific implementation method for this step is as follows:

[0078] After the gas redistribution process within the detection pool is completed and a dynamic equilibrium flow state is established, temperature-controlled convection balance regulation is implemented to further stabilize the gas transport environment. In this stage, heating and cooling units located around the detection pool contact the pool wall independently. The heating units employ a high-temperature resistance wire winding structure, enabling uniform heating of the pool wall within a short time; the cooling units achieve cooling through the flow of a circulating cooling medium. By controlling the alternating operation of the heating and cooling units, the temperature of the pool wall changes periodically within a small range, thereby creating temperature-driven gas convection within the detection pool. During the heating phase, the gas temperature near the heating surface increases and its density decreases, forming an upward airflow; during the cooling phase, the gas temperature near the cooling surface decreases and its density increases, forming a downward airflow. Through the alternating action of heating and cooling, the gas within the detection pool maintains continuous vertical convection motion, further weakening the local temperature gradient based on the gas redistribution.

[0079] In the initial stage of temperature-controlled operation, the heating power and cooling medium flow rate are gradually adjusted to create a moderate temperature fluctuation range within the detection cell. The alternation between the heating and cooling units follows a fixed time cycle, with the duration of each heating or cooling cycle controlled to induce local gas convection without disrupting overall temperature stability. During operation, the heating unit transfers heat to the gas through the cell wall, gradually increasing the temperature difference between gas layers and promoting an upward flow of the upper gas. During the cooling phase, the wall temperature drops rapidly, causing the surrounding gas to cool and contract, forming a downward backflow. This alternating cycle creates a thermal driving force that forms a closed annular flow path for the gas within the detection cell in the vertical direction. Because the gas redistribution process has made the gas density more uniform, the convection can proceed more smoothly, allowing heat to circulate and transfer within the detection cell, forming a relatively balanced heat flow structure. In this way, the temperature field within the detection cell no longer exists as a static gradient but rather maintains heat exchange through dynamic equilibrium thermal convection.

[0080] After gas convection is gradually established, the time ratio of the heating and cooling stages is adjusted according to changes in gas flow state to further improve the uniformity of the temperature field. By extending the duration of the heating stage, the upward flow of gas is fully formed, thereby promoting the return velocity of gas in the cold zone. When the temperature distribution within the detection pool tends to stabilize, the duration of the cooling stage is appropriately extended to rebalance the overall heat. During this process, the gas flow direction inside the detection pool automatically adjusts with temperature changes, forming a continuous convection cycle. The gas continuously exchanges heat during its upward and return flow, keeping the temperature difference within the detection pool within a minimal range and achieving a more balanced heat distribution. Simultaneously, the momentum of the gas flow is periodically replenished in the convection path, maintaining the continuous flow state of the gas within the detection pool. Since gas redistribution has eliminated the original stratification structure, the implementation of convection balance control can maintain a consistent gas flow rate throughout the entire range, coordinating the gas transport rates in different areas within the detection pool and preventing the recurrence of local stagnation.

[0081] Finally, through the long-term effect of alternating fine-tuning during the heating and cooling stages, the heat flow direction inside the detection cell gradually stabilizes, and the gas temperature distribution changes from periodic fluctuations to a stable and balanced state. At this point, a persistent convective equilibrium structure is formed inside the detection cell, and the gas is transferred at an approximately uniform rate throughout the entire detection area. Heat achieves self-homogenization during convection, and any instantaneous temperature difference caused by gas source fluctuations or changes in ambient temperature can be balanced within a short time. By maintaining this temperature-controlled fine-tuning process, the temperature field inside the detection cell remains in dynamic equilibrium, the gas flow direction is stable and consistent, and the gas migration path within the detection area remains continuous in both time and space. This control method not only makes the gas flow smoother but also ensures the self-stabilizing characteristics of gas thermal convection at a physical level, enabling the detection cell to maintain a constant gas transfer rate during long-term operation. As a result, the detection signal has a more linear time response, and the repeatability and stability of the detection results are fully guaranteed.

[0082] Through the continuous execution of the above steps, the convective balance of the gas inside the detection cell is controlled by temperature regulation. Alternating fine-tuning during heating and cooling continuously optimizes the temperature field distribution within the detection cell, maintaining dynamic consistency between the gas flow direction and transport rate. This further enhances the stability of the gas transport environment based on gas redistribution. While maintaining the thermal balance of the detection cell, this process eliminates uneven gas migration caused by localized temperature differences, providing stable thermal flow support for the chromatograph to maintain high-precision detection performance during long-term operation.

[0083] Step 5: Based on the stable gas transport state obtained after convection balance regulation, establish a signal drift self-suppression mechanism, dynamically correct the time reference of the detection signal according to the real-time change of the gas transport rate, and actively compensate for the nonlinear drift of the detection response, thereby ensuring the complete acquisition and quantitative output accuracy of low concentration component signals.

[0084] The specific implementation method for this step is as follows:

[0085] After achieving convection balance control and obtaining a stable gas transport state, a signal drift self-suppression mechanism is established to ensure time consistency of the detection signal during transmission and response. The goal of this stage is to enable the detection signal to automatically adjust its time reference based on real-time changes in the gas transport rate, thereby avoiding lag or advance of the detection signal caused by minute changes in gas flow velocity. To this end, two gas characteristic detection points are selected at the inlet and outlet of the detection cell, utilizing the gas flow characteristics under convection balance. These two monitoring points correspond to key locations where gas enters and leaves the detection area, respectively, with a constant gas transport path between them. The time interval between the monitoring points represents the actual gas transport time as the gas flows in the detection cell. By continuously measuring the gas transport time difference between the two monitoring points, the real-time trend of gas transport rate changes can be obtained. This transport rate serves as a fundamental parameter for adjusting the time reference of the signal drift self-suppression mechanism, allowing the detection signal to be corrected for time offset based on the current gas flow state before output.

[0086] After obtaining real-time data on the gas transfer rate, the time reference for the detection response is dynamically matched through synchronous trigger control of the detection signal acquisition device. When the gas flow velocity changes slightly, the propagation time of the detection signal in the output channel will also experience a slight shift. To eliminate this shift, the detection signal acquisition device uses the gas transfer rate as a reference when receiving signals and adjusts the signal sampling sequence according to the actual migration speed of the gas in the detection cell. Thus, when the gas flows quickly in the detection cell, the signal sampling interval is automatically shortened; when the gas flows slowly, the sampling interval is correspondingly extended, keeping the signal acquisition synchronized with the actual gas transfer. This synchronous adjustment process ensures that the detection signal always corresponds to the actual passage time of the gas within the detection area in the time dimension, thereby avoiding the accumulation of signal drift caused by flow rate fluctuations. Simultaneously, the peak shape of the detection signal is balanced in real time during the output process, ensuring that the correspondence between the peak position and retention time is not affected by changes in the gas transfer rate, maintaining a stable linear distribution of the signal output curve on the time axis.

[0087] After dynamically correcting the time reference for signal acquisition, the correspondence between signal amplitude and time is coordinated in real time to further suppress nonlinear drift in the detection response. Under stable gas conditions regulated by convection equilibrium, the gas transport rate fluctuation within the detection cell is small, but it may still undergo subtle changes due to external temperature variations or fine adjustments in gas viscosity. These minute changes can cause a non-linear response time in the detection signal. Therefore, a real-time correspondence between gas transport rate changes and signal response time is established simultaneously with signal acquisition. During the output phase, the detection signal amplitude is corrected based on the current gas flow rate trend, dynamically compensating for the difference in response time between high-concentration and low-concentration signals. When the gas transport rate slightly increases, the output time of the signal peak is corrected forward; when the gas transport rate slightly decreases, the output time of the signal peak is corrected backward, ensuring the response curve of the detection signal remains smooth and continuous. In this way, nonlinear drift is effectively suppressed, the time delay of the signal peak is eliminated, and the temporal accuracy of the detection results is maintained.

[0088] Finally, during the continuous operation of the signal drift suppression mechanism, the time reference and amplitude relationship of the detection signal are continuously adjusted to ensure that low-concentration component signals are completely captured during acquisition. When the gas transmission speed in the detection cell remains stable, the signal suppression mechanism is in a fine-tuning state, making only minor corrections to the signal time reference. When the gas transmission speed fluctuates dynamically, the signal suppression mechanism automatically adjusts the output timing and amplitude relationship of the detection signal according to the change in transmission rate, ensuring that the signal response is consistent with the gas migration state. In this way, when low-concentration components pass through the detection area, their signal peaks will not lag or weaken due to changes in gas flow, thus avoiding misinterpretation by the system as baseline noise. Through continuous time reference correction and response compensation, the temporal consistency and quantitative accuracy of the detection signal are maintained over a long period, nonlinear drift is actively canceled, and the signal curve remains highly stable. This process enables the chromatograph to maintain its sensitive response to trace components even during long-term operation, ensuring the reliability and repeatability of the detection data.

[0089] Through the above steps, relying on the stable gas transport state obtained after convection balance control, a signal drift self-suppression mechanism based on real-time changes in gas transport rate was established. This mechanism achieves active compensation for nonlinear drift by dynamically correcting the time reference and amplitude of the detection signal, thereby ensuring the complete output and quantitative accuracy of low-concentration component signals. The entire process establishes a precise temporal correspondence between gas transport and detection signals, ensuring that the chromatograph maintains the stability and linearity of its detection response even under complex operating environments.

[0090] This invention establishes a dynamic mapping model of the gas thermal field within the detection cell and implements pulsating airflow disturbance and pressure oscillation control, thereby making the temperature and density distribution of the gas within the detection cell more uniform and eliminating thermal stratification and stagnant layer structures caused by uneven heating. During gas flow, continuous convective exchange is maintained, allowing heat to be transferred evenly within the detection area, thus ensuring a stable and consistent gas transport path within the detection cell. This process effectively avoids signal delay and peak distortion caused by local gas stagnation, restoring a linear correspondence between detection response time and amplitude, and improving the stability and repeatability of the detection system.

[0091] This invention establishes a signal drift self-suppression mechanism after convection balance control, enabling the detection signal to adjust the time reference in real time according to the dynamic changes in gas transport rate, automatically offsetting nonlinear drift. This self-suppression process maintains the complete output of low-concentration component signals, preventing weak signals from being weakened or misinterpreted as noise due to gas flow rate fluctuations during detection. This improves detection sensitivity and quantitative accuracy, allowing the chromatograph to maintain stable analytical performance and highly reliable trace component identification capabilities even under long-term operating conditions.

[0092] This invention provides, for example Figure 2 The fault diagnosis and analysis system for a chromatograph shown includes a gas thermal field mapping module, a gas disturbance formation module, a gas redistribution control module, a convection balance control module, and a signal drift self-suppression module.

[0093] Gas thermal field mapping module: Based on the real-time temperature distribution information inside the chromatograph detection cell, a dynamic mapping model of the gas thermal field is established, and a temperature gradient distribution map inside the detection cell is generated through continuous acquisition by distributed multi-point temperature sensing units.

[0094] Gas disturbance formation module: Based on the temperature gradient distribution map output by the gas thermal field dynamic mapping model, a controllable micro-amplitude pulsating airflow is applied in the air intake path of the detection cell. By adjusting the pulsation frequency and amplitude, the gas flow state is disturbed, so that a diffusible gas disturbance zone is formed inside the detection cell.

[0095] Gas redistribution control module: Based on the flow characteristics of the gas disturbance zone, a gas redistribution process is constructed. In this process, the periodic oscillation of the inlet pressure is used to drive the continuous mixing of gases of different density layers, so that the gas migration path in the detection cell cavity is kept in dynamic equilibrium.

[0096] Convection balance control module: After the gas redistribution process is completed, temperature-controlled convection balance regulation is implemented. By alternating fine-tuning the heating and cooling stages of the detection cell, the direction of gas heat flow is stabilized, and the temperature field distribution and gas transport rate inside the detection cell are balanced.

[0097] Signal drift self-suppression module: Based on the stable gas transmission state obtained after convection balance control, a signal drift self-suppression mechanism is established. The time reference of the detection signal is dynamically corrected according to the real-time change of the gas transmission rate, and the nonlinear drift of the detection response is actively compensated.

[0098] The present invention provides a fault diagnosis and analysis method for a chromatograph, which is implemented by the above-mentioned fault diagnosis and analysis system for a chromatograph. For details of the specific method and process of the fault diagnosis and analysis system for a chromatograph, please refer to the above-mentioned embodiment of the fault diagnosis and analysis method for a chromatograph, which will not be repeated here.

[0099] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A fault diagnosis and analysis method for a chromatograph, characterized in that, Includes the following steps: Step 1: Based on the real-time temperature distribution information inside the chromatograph detection cell, establish a dynamic mapping model of the gas thermal field, and generate a temperature gradient distribution map inside the detection cell through continuous acquisition by distributed multi-point temperature sensing units. Step 2: Based on the temperature gradient distribution map output by the gas thermal field dynamic mapping model, apply a controllable micro-amplitude pulsating airflow in the air inlet path of the detection cell. By adjusting the pulsation frequency and amplitude, the gas flow state is disturbed, so that a diffusible gas disturbance zone is formed inside the detection cell. Step 3: Based on the flow characteristics of the gas disturbance zone, a gas redistribution process is constructed. In this process, the periodic oscillation of the inlet pressure is used to drive the continuous mixing of gases in different density layers, so that the gas migration path in the detection cell cavity remains in dynamic equilibrium. Step 4: After the gas redistribution process is completed, implement temperature-controlled convection balance regulation. By alternating fine-tuning the heating and cooling stages of the detection cell, stabilize the direction of gas heat flow and balance the temperature field distribution and gas transport rate inside the detection cell. Step 5: Based on the stable gas transport state obtained after convection balance control, establish a signal drift self-suppression mechanism, dynamically correct the time reference of the detection signal according to the real-time change of the gas transport rate, and actively compensate for the nonlinear drift of the detection response.

2. The fault diagnosis and analysis method for a chromatograph according to claim 1, characterized in that, The steps to establish a dynamic mapping model of a gas thermal field include: Several temperature sensing units are installed at different heights and orientations in the detection pool cavity. The temperature sensing units are arranged at equal intervals from bottom to top along the axial direction of the detection pool and set at multiple angular positions in the radial direction to continuously collect temperature data inside the detection pool. The temperature data collected by the temperature sensing unit is processed to correspond to time series and spatial location, and supplemented by interpolation of temperature difference between adjacent measuring points to form a temperature information set with temporal continuity and spatial integrity. Based on the geometric dimensions, gas inlet location, gas outlet direction, and internal structural features of the detection cell, the temperature information is spatially located, a dynamic mapping model of the gas thermal field is established, and the thermal stratification state of the gas inside the detection cell in the vertical direction is determined. Temperature gradient distribution map is generated using temperature data output from the gas thermal field dynamic mapping model. The spatial coordinates of the detection cell are used as the horizontal and vertical axes, and the temperature difference is used as the color change index to characterize the thermal stratification distribution of the gas in the detection cell.

3. The fault diagnosis and analysis method for a chromatograph according to claim 2, characterized in that, During the generation of the temperature gradient distribution map, the sampling frequency of the temperature sensing unit remains consistent, and the temperature data is integrated sequentially according to the acquisition time sequence so that each time segment corresponds to a complete gas thermal field state. By continuously generating the temperature gradient distribution map, the dynamic changes of the temperature field in the detection pool are reflected in real time to identify the formation area of ​​gas thermal stratification.

4. The method for fault diagnosis and analysis of a chromatograph according to claim 2, characterized in that, The steps of applying a controllable micro-amplitude pulsating airflow in the intake path of the detection cell include: A gas input end, a regulating chamber, and an airflow control valve are set at the air intake path of the detection cell. The airflow control valve is connected to the gas source through a high-temperature resistant flexible material, and the gas flow rate is periodically opened and closed through a precision drive unit to form a continuous micro-airflow pulsation before the gas enters the detection cell. Based on the temperature gradient distribution map output by the gas thermal field dynamic mapping model, the propagation direction, frequency and amplitude of the pulsation are adjusted so that the airflow disturbance is concentrated on the area with a high temperature difference, thereby breaking the thermal stratification formed by the temperature gradient in the detection cell. By continuously fine-tuning the pulsation parameters of the airflow, the gas disturbance zone expands along the axial direction of the detection cell and forms a periodically fluctuating disturbance wave, which causes the gas in the detection cell to generate coupled vibration in the vertical direction. By maintaining the periodic input of pulsating airflow, a continuous micro-perturbation equilibrium state is formed inside the detection cell. The gas dynamically exchanges energy and momentum between perturbation and recovery, thus maintaining the homogenization of the gas thermal field.

5. The method for fault diagnosis and analysis of a chromatograph according to claim 4, characterized in that, The pulsation frequency and amplitude adjustment range of the airflow control valve are adaptively set according to the magnitude of the temperature difference in the temperature gradient distribution diagram. When the temperature difference in the detection cell increases, the pulsation frequency and airflow amplitude are increased to enhance the disturbance effect on the thermal stratification area. When the temperature difference decreases, the pulsation frequency and airflow amplitude are reduced to maintain the stable diffusion state of the gas disturbance zone inside the detection cell.

6. The method for fault diagnosis and analysis of a chromatograph according to claim 4, characterized in that, The steps involved in constructing a gas redistribution process include: Controlled pressure periodic oscillations are introduced at the air intake path of the detection pool. The pressure periodic oscillations are achieved through the cooperation of the pressure stabilizing component at the air supply end and the air intake control valve, so that the gas inside the detection pool exhibits periodic pressure fluctuations in the time dimension and is coupled with the gas disturbance zone. Pressure fluctuations are used to drive the periodic compression and expansion of gases in different density layers within the detection cell, causing volumetric flow between gas layers and promoting continuous mixing and redistribution of gases in the vertical direction. By adjusting the duration and frequency of pressure oscillation, the flow cycle between gas layers and the residence time of gas in the detection cell are coordinated, which promotes the formation of a spiral circulation path of gas in the vertical and radial directions, and homogenizes the gas density distribution and temperature gradient. The periodic oscillation of the intake pressure is maintained, so that the gas flow state in the detection cell is continuously kept between dynamic and equilibrium, and sufficient mixing is achieved throughout the entire cavity.

7. The method for fault diagnosis and analysis of a chromatograph according to claim 6, characterized in that, The frequency of the pressure periodic oscillation is set to match the natural response frequency of the gas disturbance zone in the detection pool, and the pressure fluctuation amplitude is controlled within a range that does not affect the overall flow field stability of the detection pool, so that gases of different density layers form a continuous and uniform mixed flow under the action of periodic oscillation.

8. A fault diagnosis and analysis method for a chromatograph according to claim 6, characterized in that, The steps for implementing temperature-controlled convection balance regulation include: Heating and cooling units are set up around the detection pool. The heating unit uses a high-temperature resistance wire winding structure to uniformly heat the detection pool wall, while the cooling unit cools the pool by circulating cooling medium. The alternating operation of the two units creates temperature-driven gas convection inside the detection pool. By gradually adjusting the heating power and the flow rate of the cooling medium, the temperature of the detection pool wall changes periodically within a small range, causing an upward airflow to be generated during the heating stage and a downward airflow to be formed during the cooling stage, thereby establishing a closed-loop convection path in the vertical direction. Adjust the time ratio of heating and cooling stages according to the changes in gas flow state, extend the heating or cooling duration to balance heat distribution, and keep the gas flowing continuously during the rising and reflux process to achieve heat exchange. By maintaining alternating fine-tuning between the heating and cooling phases, a stable convective equilibrium structure is formed inside the detection cell, thereby allowing the gas to be transported at an approximately uniform speed throughout the entire detection area.

9. A fault diagnosis and analysis method for a chromatograph according to claim 8, characterized in that, The steps to establish a signal drift self-suppression mechanism include: After completing the convection balance control and obtaining a stable gas transport state, gas characteristic detection points at the inlet and outlet of the detection cell are selected, and the gas transport time difference between the two detection points is measured to obtain the gas transport rate change trend in real time. Based on the real-time changes in gas transmission rate, the time reference of the detection response is dynamically matched through the synchronous trigger control of the detection signal acquisition device, so that the signal acquisition and the actual gas transmission are kept synchronized. Based on the trend of gas transmission rate change, the amplitude and time correspondence of the detection signal are dynamically coordinated. By correcting the peak output time of the signal, active compensation for nonlinear drift of the detection response is achieved. During the continuous operation of the signal drift suppression mechanism, the output timing and amplitude relationship of the detection signal are automatically adjusted according to the change in gas transmission rate, so that the low-concentration component signal is fully acquired.

10. A fault diagnosis and analysis system for a chromatograph, used to implement the fault diagnosis and analysis method for a chromatograph according to any one of claims 1-9, characterized in that, It includes a gas thermal field mapping module, a gas disturbance formation module, a gas redistribution control module, a convection balance control module, and a signal drift self-suppression module; Gas thermal field mapping module: Based on the real-time temperature distribution information inside the chromatograph detection cell, a dynamic mapping model of the gas thermal field is established, and a temperature gradient distribution map inside the detection cell is generated through continuous acquisition by distributed multi-point temperature sensing units. Gas disturbance formation module: Based on the temperature gradient distribution map output by the gas thermal field dynamic mapping model, a controllable micro-amplitude pulsating airflow is applied in the air intake path of the detection cell. By adjusting the pulsation frequency and amplitude, the gas flow state is disturbed, so that a diffusible gas disturbance zone is formed inside the detection cell. Gas redistribution control module: Based on the flow characteristics of the gas disturbance zone, a gas redistribution process is constructed. In this process, the periodic oscillation of the inlet pressure is used to drive the continuous mixing of gases of different density layers, so that the gas migration path in the detection cell cavity is kept in dynamic equilibrium. Convection balance control module: After the gas redistribution process is completed, temperature-controlled convection balance regulation is implemented. By alternating fine-tuning the heating and cooling stages of the detection cell, the direction of gas heat flow is stabilized, and the temperature field distribution and gas transport rate inside the detection cell are balanced. Signal drift self-suppression module: Based on the stable gas transmission state obtained after convection balance control, a signal drift self-suppression mechanism is established. The time reference of the detection signal is dynamically corrected according to the real-time change of the gas transmission rate, and the nonlinear drift of the detection response is actively compensated.

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