A method and system for on-line identification and self-cleaning of a valve port of a micro proportional valve

Abstract

The application discloses a kind of micro proportional valve port pollution online identification and self-clearing method and system, comprising: establishing the reference response data under the clean state of proportional valve, response data includes the pressure before valve, the pressure after valve, response time and steady-state pressure error;During the normal operation of proportional valve, superimposed detection disturbance is added to the current control signal of proportional valve, and the current response characteristics of valve port are extracted;Current response characteristics are compared with reference response data, and valve port pollution identification index is calculated;According to valve port pollution identification index, determine the valve port pollution state and determine whether to trigger self-clearing action;When triggering self-clearing action, control proportional valve to execute self-clearing action by valve core dithering, short-time large-opening pulse or rapid pressure relief;After a round of self-clearing action, return to apply detection disturbance again, according to the pollution identification index after clearing and the pollution improvement rate before and after clearing, verify the clearing effect and determine whether to execute multiple self-clearing actions.

Description

Technical Field

[0001] This invention relates to the field of microfluidic control and precision pneumatic control technology, and more specifically to a method and system for online identification and self-cleaning of contamination at the valve port of a micro proportional valve, applicable to the health monitoring and maintenance of proportional valves in gas microflow regulation, precision pressure control, pneumatic actuators, and microfluidic control systems. Background Technology

[0002] Miniature proportional valves are a type of precision control element used to achieve continuous regulation of minute flow rates of gas or liquid. They are widely used in medical equipment, analytical instruments, pneumatic actuators, precision pressure control systems, and microfluidic control systems.

[0003] However, in actual operation of miniature proportional valves, due to the small valve orifice size and narrow flow channel clearance, when the working medium contains tiny particles, oil mist, condensate, crystals, dust, or wear debris from seals, contaminants easily adhere to the valve orifice, valve core end face, valve seat sealing surface, or tiny throttling channels. In the initial stage, this type of contamination often does not lead to complete valve blockage, but rather manifests as reduced flow at low opening degrees, increased opening current, slower pressure response, flow-control signal curve drift, increased valve orifice hysteresis, and decreased repeatability. For micro-flow control scenarios, even slight contamination can cause significant control errors, affecting system pressure stability, flow consistency, and long-term operational reliability.

[0004] To address fluid channel blockage or contamination issues, existing technologies typically employ the following approaches: First, installing filters or screens before the valve to reduce particulate matter entering the proportional valve; second, disassembling and cleaning pipelines, filters, or valve bodies, replacing filter elements, or manually draining contaminants during equipment maintenance; third, using pipeline pressure differentials, flow resistance changes, or machine learning methods to determine pipeline leaks, blockages, and other fault conditions; and fourth, using backwash filters or similar structures to achieve cleaning through reverse flow after filter elements become clogged.

[0005] However, the existing processing methods described above still have the following shortcomings:

[0006] First, existing filtration methods are mainly used to block larger particles, and it is difficult to completely prevent oil mist, condensate, small particles or crystals from entering the valve port area of ​​the miniature proportional valve. For miniature proportional valves with small valve port gaps, even if the size of the contaminants is small, they may gradually accumulate near the valve port and cause the flow characteristics to drift. Second, existing blockage detection methods are mostly geared towards pipelines, filters, or high-flow-rate fluid systems, primarily determining whether there is significant blockage or leakage in the pipeline. They are difficult to identify the early contamination state at the valve orifice of miniature proportional valves. Contamination at the valve orifice of miniature proportional valves is characterized by localization, gradualness, and incomplete blockage. Relying solely on the total system pressure, total flow rate, or human experience makes it difficult to detect slight contamination at the valve orifice in a timely manner. Third, existing proportional valve anti-pollution designs are mostly based on structural anti-pollution, reducing valve core jamming, or improving friction pairs. The main purpose is to reduce the impact of contaminants on valve core movement and pressure regulation performance. However, they usually cannot actively judge the degree of contamination at the valve port, nor can they automatically perform unblocking actions based on the contamination status during valve operation. Fourth, existing backwashing or cleaning methods are mostly used in filters, pipelines or switchable flow path structures. They usually require additional cleaning channels, sewage channels or manual maintenance operations, and the structure is large in size. It is difficult to apply them directly to the internal valve ports of miniature proportional valves. For miniature proportional valves, frequent disassembly and cleaning not only affect the continuous operation of the equipment, but may also damage the assembly accuracy of the valve core, valve seat and seals.

[0007] Therefore, it is urgent for those skilled in the art to solve the problems of difficulty in timely identification of early contamination at the valve orifice of existing miniature proportional valves, the need for shutdown and disassembly for cleaning after contamination, easy drift of flow characteristics during long-term operation, and decreased control accuracy at low opening degree. Summary of the Invention

[0008] In view of the above problems, the present invention proposes an online identification and self-cleaning method for local contamination of the valve port of a miniature proportional valve to overcome or at least partially solve the above problems. The method aims to determine the contamination status of the valve port by means of the valve's own control signal, pressure response or flow response characteristics without disassembling the valve body or setting up additional complex cleaning equipment. When the contamination reaches a preset level, the method automatically performs clearing actions such as micro-disturbance, pulse flushing or valve core shaking, thereby improving the control accuracy, anti-contamination ability and maintenance convenience of the miniature proportional valve during long-term operation.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A method for online identification and self-cleaning of contamination at the valve orifice of a miniature proportional valve includes the following steps: S1. Establish baseline response data for the proportional valve under clean conditions. The response data includes inlet valve pressure, outlet valve pressure, response time, and steady-state pressure error. S2. During the normal operation of the proportional valve, the detected disturbance is superimposed onto the current control signal of the proportional valve, and the current response characteristics of the valve port are extracted; S3. Compare the current response characteristics with the baseline response data to calculate the valve port contamination identification index; S4. Determine the valve port contamination status based on the valve port contamination identification index and determine whether to trigger the self-cleaning action; S5. When the self-cleaning action is triggered, the control proportional valve performs the self-cleaning action by valve core shaking, short-term large opening pulse or rapid pressure relief; S6. After one round of self-cleaning action is completed, return to step S2 to apply the detection disturbance again. Verify the cleaning effect based on the pollution identification index after cleaning and the pollution improvement rate before and after cleaning, and determine whether to perform multiple self-cleaning actions.

[0010] Preferably, the method for online identification and self-cleaning of contamination at the valve port of a miniature proportional valve further includes: real-time monitoring of the downstream pressure, coil current, and cleaning duration during the cleaning process; and immediately stopping the cleaning action when any of the following conditions are met: the downstream pressure is greater than the safe pressure threshold, the coil current is greater than the maximum allowable current of the coil, or the cleaning duration is greater than the maximum allowable cleaning time.

[0011] Preferably, step S1, the method for establishing the reference response data of the proportional valve under the cleaning state, is as follows: When the proportional valve is in a clean state or factory calibrated state, several sets of preset control signals are input to the proportional valve. The valve inlet pressure, valve outlet pressure, response time and steady-state pressure error corresponding to different control signals are collected, and the reference pressure difference, reference response time and reference steady-state error are calculated as the reference response data for the established clean state.

[0012] Preferably, the specific content of step S2 is as follows: During normal operation of the proportional valve, a small detection disturbance is superimposed on the current control signal of the proportional valve according to a preset cycle or when an increase in pressure control error is detected. During the detection process, the pressure before the valve, the pressure after the valve, and the control signal response are collected, and the current response characteristics of the valve port are extracted, including the current differential pressure, the current response time, and the current steady-state pressure error.

[0013] Preferably, the valve port contamination identification indicators include differential pressure deviation, response time deviation, and steady-state error deviation;

[0014] in, As a pollution identification indicator, Given the current pressure difference, As the reference pressure difference, This is the current response time. As the baseline response time, The current steady-state pressure error, As the reference steady-state pressure error, , , These are the weighting coefficients. To prevent small positive numbers with a denominator of zero.

[0015] Preferably, step S4, which determines the valve port contamination level based on the valve port contamination identification index and determines whether to trigger the self-cleaning action, specifically includes the following: when When the valve port is determined to be in a normal state, the proportional valve continues to operate normally. when If the valve port is found to be slightly contaminated, the contamination trend should be recorded and the detection cycle shortened. when When the valve port is determined to be in a state of moderate contamination, the controller triggers a self-cleaning action.

[0016] Preferably, step S4, the specific content of the self-cleaning action, is as follows: High-frequency small-amplitude vibration of valve core: The controller applies a high-frequency small-amplitude fluctuation signal to the proportional valve coil, causing the valve core to produce a small reciprocating motion near the valve seat, thereby disrupting the adhesion state of contaminants at the valve port; Short-duration large-opening pulse: The controller controls the proportional valve to open rapidly for a short time within the safe pressure range, which increases the instantaneous flow velocity at the valve port, thereby flushing out contaminants on the valve core end face, valve seat sealing surface and throttling channel; Rapid pressure relief and unblocking: The controller controls the proportional valve to perform rapid closing and rapid opening actions, causing a sudden pressure change near the valve port, which causes condensate, oil film or adhesive contaminants to leave the valve port area.

[0017] Preferably, step S5 includes: After the blockage clearing operation is completed, the controller applies a detection disturbance again, re-acquires the pressure response, and calculates the pollution identification index and the pollution improvement rate before and after the blockage clearing. If pollution identification indicators are cleared If the valve port returns to normal, the proportional valve returns to normal control mode; if If the pollution identification index is still greater than the preset threshold, but the pollution improvement rate meets the requirements and the preset maximum number of clearing operations has not been reached, then the next round of self-clearing operations will continue. If the pollution identification index is still greater than the preset threshold after multiple clearing operations, then the operation will continue. Once the preset maximum number of unblocking attempts is reached, the controller will output a maintenance alarm signal.

[0018] A miniature proportional valve port contamination online identification and self-cleaning system includes: a miniature proportional valve body, a valve inlet pressure detection unit, a valve outlet pressure detection unit, a proportional valve drive unit, a controller, and a storage unit; The inlet pressure detection unit is located at the medium inlet end of the miniature proportional valve body and is used to collect the inlet pressure. The downstream pressure detection unit is located at the medium outlet end of the miniature proportional valve body and is used to collect the downstream pressure. The proportional valve drive unit is connected to the coil of the miniature proportional valve and is used to drive the valve core to move according to the current or voltage signal output by the controller. The controller is used to establish baseline response data for the proportional valve under clean conditions based on the pressure signals from the upstream and downstream pressure detection units. This response data includes upstream pressure, downstream pressure, response time, and steady-state pressure error. During normal operation, a detection disturbance is superimposed onto the current control signal of the proportional valve, and the current response characteristics of the valve port are extracted. The current response characteristics are compared with the baseline response data to calculate the valve port contamination identification index. Based on the valve port contamination identification index, the controller determines the valve port contamination status and whether to trigger a self-cleaning action. When a self-cleaning action is triggered, the controller controls the proportional valve to perform the self-cleaning action through valve core jitter, short-duration large-opening pulses, or rapid pressure relief. After one round of self-cleaning action, a detection disturbance is applied again. The cleaning effect is verified based on the post-cleaning contamination identification index and the contamination improvement rate before and after cleaning, and it is determined whether to perform multiple self-cleaning actions. The storage unit is used to store the baseline response data, contamination status judgment threshold, and self-cleaning action control parameters of the proportional valve in the clean state.

[0019] Preferably, the controller is also used to monitor the valve downstream pressure, coil current and unblocking duration in real time during the unblocking process. When any of the following conditions are met, the unblocking action is stopped immediately.

[0020] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a method and system for online identification and self-cleaning of contamination at the valve port of a miniature proportional valve, which has the following beneficial effects: By collecting the pressure before and after the valve and the control signal response, the valve port contamination identification index is calculated. It can identify abnormal states such as particle adhesion, oil mist deposition, condensate blockage or crystal accumulation before the valve port is completely blocked, realize online early identification of contamination at the valve port of the miniature proportional valve, and improve the timeliness of contamination detection. When the pollution identification index exceeds the preset threshold, the controller automatically triggers the valve core to perform high-frequency small-amplitude vibration, short-term large-opening pulse, rapid pressure relief or multiple reciprocating flushing and other anti-clogging actions, so that the pollutants fall off from the valve core end face, valve seat sealing surface or small throttling channel, realizing non-stop self-cleaning, reducing manual maintenance, thereby reducing the number of times to stop disassembly, cleaning and replacement of valve parts, and improving the continuous operation capability of the equipment; By using a closed-loop process of "identification-unblocking-verification-rejuvenation", the contamination status of the valve port can be continuously monitored and actively addressed, which can reduce the impact of contamination on low flow regulation accuracy and improve the pressure response consistency, flow regulation stability and reliability of the miniature proportional valve during long-term operation. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0022] Figure 1 This is a flowchart of an online identification and self-cleaning method for contamination at the valve port of a miniature proportional valve, provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of an online identification and self-cleaning system for contamination at the valve port of a miniature proportional valve, provided in an embodiment of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1 This invention discloses an online identification and self-cleaning method for contamination at the valve port of a miniature proportional valve, comprising the following steps: S1. Establish baseline response data for the proportional valve under clean conditions. The response data includes inlet valve pressure, outlet valve pressure, response time, and steady-state pressure error. S2. During the normal operation of the proportional valve, the detected disturbance is superimposed onto the current control signal of the proportional valve, and the current response characteristics of the valve port are extracted; S3. Compare the current response characteristics with the baseline response data to calculate the valve port contamination identification index; S4. Determine the valve port contamination status based on the valve port contamination identification index and determine whether to trigger the self-cleaning action; S5. When the self-cleaning action is triggered, the control proportional valve performs the self-cleaning action by valve core shaking, short-term large opening pulse or rapid pressure relief; S6. After one round of self-cleaning action is completed, return to step S2 to apply the detection disturbance again. Verify the cleaning effect based on the pollution identification index after cleaning and the pollution improvement rate before and after cleaning, and determine whether to perform multiple self-cleaning actions.

[0025] To further implement the above technical solution, a method for online identification and self-cleaning of contamination at the valve orifice of a miniature proportional valve further includes: real-time monitoring of the downstream pressure, coil current, and cleaning duration during the cleaning process; and immediately stopping the cleaning action when any of the following conditions are met: the downstream pressure exceeds the safe pressure threshold, the coil current exceeds the maximum allowable current of the coil, or the cleaning duration exceeds the maximum allowable cleaning time. In this embodiment, the specific conditions are as follows:

[0026] in, , These are the valve downstream pressure and coil current, which are monitored in real time during the unblocking process. For the safety pressure threshold, The maximum allowable current for the coil, For the duration of congestion clearing, This is the maximum allowable time for clearing congestion.

[0027] To further implement the above technical solution, step S1, the method for establishing the reference response data of the proportional valve under the cleaning state, is as follows: When the proportional valve is in a clean state or factory calibrated state, several sets of preset control signals are input to the proportional valve. The valve inlet pressure, valve outlet pressure, response time and steady-state pressure error corresponding to different control signals are collected, and the reference pressure difference, reference response time and reference steady-state error are calculated as the reference response data for the established clean state.

[0028] In this embodiment, the response time is the time it takes for the downstream pressure to change from the point of application of a control signal or detection of a disturbance until it reaches and stabilizes within the allowable error range of the target pressure; the steady-state pressure error is the deviation obtained by comparing the average value of the downstream pressure collected within a preset steady-state time period after the pressure response stabilizes with the target pressure; the reference response data is determined according to different control signals, and each set of preset control signals is repeatedly collected. The average value of the valve inlet and outlet pressure difference, response time and steady-state pressure error obtained under the same control signal is taken as the reference data corresponding to the control signal.

[0029] In this embodiment, the pressure difference before and after the valve is:

[0030] in, The pressure before the valve, The pressure after the valve, This represents the pressure difference between the valve and its upstream and downstream sides.

[0031] To further implement the above technical solution, the specific content of step S2 is as follows: During normal operation of the proportional valve, a small detection disturbance is superimposed on the current control signal of the proportional valve according to a preset cycle or when an increase in pressure control error is detected. During the detection process, the pressure before the valve, the pressure after the valve, and the control signal response are collected, and the current response characteristics of the valve port are extracted, including the current differential pressure, the current response time, and the current steady-state pressure error.

[0032] In this embodiment, the detected disturbance includes a small-amplitude step signal, a short-time pulse signal, or a low-amplitude sine wave signal; the amplitude of the detected disturbance is less than a preset ratio of the amplitude of the normal control signal, so as to avoid affecting the normal operation of the system.

[0033] To further implement the above technical solutions, valve port contamination identification indicators include differential pressure deviation, response time deviation, and steady-state error deviation.

[0034] in, As a pollution identification indicator, Given the current pressure difference, As the reference pressure difference, This is the current response time. As the baseline response time, The current steady-state pressure error, As the reference steady-state pressure error, , , These are the weighting coefficients. To prevent small positive numbers with a denominator of zero.

[0035] In this embodiment, when When the value is small, it indicates that the valve port response characteristics are close to a clean state; when An increase indicates that the valve port may be contaminated, partially blocked, or have reduced flow capacity.

[0036] To further implement the above technical solution, step S4, which determines the valve port contamination level based on the valve port contamination identification index and whether to trigger the self-cleaning action, specifically includes the following: when When the valve port is determined to be in a normal state, the proportional valve continues to operate normally. when If the valve port is found to be slightly contaminated, the contamination trend should be recorded and the detection cycle shortened. when When the valve port is determined to be in a state of moderate contamination, the controller triggers a self-cleaning action.

[0037] To further implement the above technical solution, step S4, the specific content of the self-cleaning action, is as follows: High-frequency small-amplitude vibration of valve core: The controller applies a high-frequency small-amplitude fluctuation signal to the proportional valve coil, causing the valve core to produce a small reciprocating motion near the valve seat, thereby disrupting the adhesion state of contaminants at the valve port; In this embodiment, the control signal is represented as:

[0038] in, For clearing congestion control signals, For clearing congestion, the baseline control signal, The amplitude of the jitter. This refers to the jitter frequency; Short-duration large-opening pulse: The controller controls the proportional valve to open rapidly for a short time within the safe pressure range, which increases the instantaneous flow velocity at the valve port, thereby flushing out contaminants on the valve core end face, valve seat sealing surface and throttling channel; Rapid pressure relief and unblocking: The controller controls the proportional valve to perform rapid closing and rapid opening actions, causing a sudden pressure change near the valve port, which causes condensate, oil film or adhesive contaminants to leave the valve port area.

[0039] To further implement the above technical solution, step S5 includes: After one round of clearing action is completed, the controller applies a detection disturbance again, re-collects the pressure response, and calculates the pollution identification index and the pollution improvement rate before and after clearing. If pollution identification indicators are cleared If the valve port returns to normal, the proportional valve returns to normal control mode; if Still greater than the preset threshold However, if the pollution improvement rate meets the requirements and the preset maximum number of clearing operations has not been reached, the next round of self-clearing will continue. If the pollution identification index is still greater than the preset threshold after multiple clearing operations, the process will continue. Once the preset maximum number of unblocking attempts is reached, the controller will output a maintenance alarm signal.

[0040] In this embodiment, the pollution improvement rate before and after unblocking is expressed as:

[0041] in, For pollution improvement rate, Pollution identification indicators before clearing blockages. These are indicators for identifying pollution after blockage clearing.

[0042] Example 2 A miniature proportional valve port contamination online identification and self-cleaning system includes: a miniature proportional valve body, a valve inlet pressure detection unit, a valve outlet pressure detection unit, a proportional valve drive unit, a controller, and a storage unit; The inlet pressure detection unit is located at the medium inlet end of the miniature proportional valve body and is used to collect the inlet pressure. The downstream pressure detection unit is located at the medium outlet end of the miniature proportional valve body and is used to collect the downstream pressure. The proportional valve drive unit is connected to the coil of the miniature proportional valve and is used to drive the valve core to move according to the current or voltage signal output by the controller. The controller is used to establish baseline response data for the proportional valve under clean conditions based on the pressure signals from the upstream and downstream pressure detection units. This response data includes upstream pressure, downstream pressure, response time, and steady-state pressure error. During normal operation, a detection disturbance is superimposed onto the current control signal of the proportional valve, and the current response characteristics of the valve port are extracted. The current response characteristics are compared with the baseline response data to calculate the valve port contamination identification index. Based on the valve port contamination identification index, the controller determines the valve port contamination status and whether to trigger a self-cleaning action. When a self-cleaning action is triggered, the controller controls the proportional valve to perform the self-cleaning action through valve core jitter, short-duration large-opening pulses, or rapid pressure relief. After one round of self-cleaning action, a detection disturbance is applied again. The cleaning effect is verified based on the post-cleaning contamination identification index and the contamination improvement rate before and after cleaning, and it is determined whether to perform multiple self-cleaning actions. The storage unit is used to store the baseline response data, contamination status judgment threshold, and self-cleaning action control parameters of the proportional valve in the clean state.

[0043] In this embodiment, the miniature proportional valve body includes a valve body, a valve seat, a valve core, an elastic reset element, a coil, and a fluid passage; the upstream pressure detection unit and the downstream pressure detection unit are independent pressure sensors or utilize the original pressure detection signal of the system, without being forced to rely on an external flow sensor, and are suitable for miniature proportional valve systems with compact structure and limited installation space.

[0044] To further implement the above technical solution, the controller is also used to monitor the valve downstream pressure, coil current and unblocking duration in real time during the unblocking process. When any of the following conditions are met, the unblocking action is stopped immediately.

[0045] Example 3 A computer-readable storage medium storing a computer program thereon, characterized in that, when executed by a processor, the program implements online identification and self-cleaning of contamination at the valve port of a miniature proportional valve according to Embodiment 1.

[0046] Example 4 A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the program to implement a method for online identification and self-cleaning of contamination at the valve port of a miniature proportional valve, as described in Embodiment 1.

[0047] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0048] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for online identification and self-cleaning of contamination at the valve orifice of a miniature proportional valve, characterized in that, Includes the following steps: S1. Establish baseline response data for the proportional valve under clean conditions. The response data includes inlet pressure, outlet pressure, response time, and steady-state pressure error. S2. During the normal operation of the proportional valve, the detected disturbance is superimposed onto the current control signal of the proportional valve, and the current response characteristics of the valve port are extracted; S3. Compare the current response characteristics with the baseline response data to calculate the valve port contamination identification index; S4. Determine the valve port contamination status based on the valve port contamination identification index and determine whether to trigger the self-cleaning action; S5. When the self-cleaning action is triggered, the control proportional valve performs the self-cleaning action by valve core shaking, short-term large opening pulse or rapid pressure relief; S6. After one round of self-cleaning action is completed, return to step S2 to apply the detection disturbance again. Verify the cleaning effect based on the pollution identification index after cleaning and the pollution improvement rate before and after cleaning, and determine whether to perform multiple self-cleaning actions.

2. The method for online identification and self-cleaning of contamination at the valve port of a miniature proportional valve as described in claim 1, characterized in that, Also includes: During the unblocking process, the valve downstream pressure, coil current, and unblocking duration are monitored in real time. When any of the following conditions are met, the unblocking action is immediately stopped.

3. The method for online identification and self-cleaning of contamination at the valve port of a miniature proportional valve as described in claim 1, characterized in that, Step S1, the method for establishing the baseline response data of the proportional valve under the cleaning state is as follows: When the proportional valve is in a clean state or factory calibrated state, several sets of preset control signals are input to the proportional valve. The valve inlet pressure, valve outlet pressure, response time and steady-state pressure error corresponding to different control signals are collected, and the reference pressure difference, reference response time and reference steady-state error are calculated as the reference response data for the established clean state.

4. The method for online identification and self-cleaning of contamination at the valve port of a miniature proportional valve as described in claim 1, characterized in that, The specific content of step S2 is as follows: During normal operation of the proportional valve, a small detection disturbance is superimposed on the current control signal of the proportional valve according to a preset cycle or when an increase in pressure control error is detected. During the detection process, the pressure before the valve, the pressure after the valve, and the control signal response are collected, and the current response characteristics of the valve port are extracted, including the current differential pressure, the current response time, and the current steady-state pressure error.

5. The method for online identification and self-cleaning of contamination at the valve port of a miniature proportional valve as described in claim 1, characterized in that, Valve port contamination identification indicators include differential pressure deviation, response time deviation, and steady-state error deviation; in, As a pollution identification indicator, Given the current pressure difference, As the reference pressure difference, This is the current response time. As the baseline response time, The current steady-state pressure error, As the reference steady-state pressure error, , , These are the weighting coefficients. To prevent small positive numbers with a denominator of zero.

6. The method for online identification and self-cleaning of contamination at the valve port of a miniature proportional valve as described in claim 1, characterized in that, Step S4, which determines the valve port contamination level based on the valve port contamination identification index and whether to trigger the self-cleaning action, specifically includes: when When the valve port is determined to be in a normal state, the proportional valve continues to operate normally. when If the valve port is found to be slightly contaminated, the contamination trend should be recorded and the detection cycle shortened. when When the valve port is determined to be in a state of moderate contamination, the controller triggers a self-cleaning action.

7. The method for online identification and self-cleaning of contamination at the valve port of a miniature proportional valve as described in claim 1, characterized in that, Step S4, the specific content of the self-clearing blockage action is as follows: High-frequency small-amplitude vibration of valve core: The controller applies a high-frequency small-amplitude fluctuation signal to the proportional valve coil, causing the valve core to produce a small reciprocating motion near the valve seat, thereby disrupting the adhesion state of contaminants at the valve port; Short-duration large-opening pulse: The controller controls the proportional valve to open rapidly for a short time within the safe pressure range, which increases the instantaneous flow velocity at the valve port, thereby flushing out contaminants on the valve core end face, valve seat sealing surface and throttling channel; Rapid pressure relief and unblocking: The controller controls the proportional valve to perform rapid closing and rapid opening actions, causing a sudden pressure change near the valve port, which causes condensate, oil film or adhesive contaminants to leave the valve port area.

8. The method for online identification and self-cleaning of contamination at the valve port of a miniature proportional valve as described in claim 1, characterized in that, Step S5 includes: After the blockage clearing operation is completed, the controller applies a detection disturbance again, re-acquires the pressure response, and calculates the pollution identification index and the pollution improvement rate before and after the blockage clearing. If pollution identification indicators are cleared If the valve port returns to normal, the proportional valve returns to normal control mode; if If the pollution index is still greater than the preset threshold, but the preset maximum number of clearing attempts has not been reached, the next round of self-clearing will continue. If the pollution identification index is still greater than the preset threshold after multiple clearing attempts, the process will continue. Once the preset maximum number of unblocking attempts is reached, the controller will output a maintenance alarm signal.

9. A system for online identification and self-cleaning of contamination at the valve port of a miniature proportional valve, characterized in that, include: Miniature proportional valve body, valve inlet pressure detection unit, valve outlet pressure detection unit, proportional valve drive unit, controller and storage unit; The inlet pressure detection unit is located at the medium inlet end of the miniature proportional valve body and is used to collect the inlet pressure. The downstream pressure detection unit is located at the medium outlet end of the miniature proportional valve body and is used to collect the downstream pressure. The proportional valve drive unit is connected to the coil of the miniature proportional valve and is used to drive the valve core to move according to the current or voltage signal output by the controller. The controller is used to establish baseline response data for the proportional valve under clean conditions based on the pressure signals from the upstream and downstream pressure detection units. This response data includes upstream pressure, downstream pressure, response time, and steady-state pressure error. During normal operation, a detection disturbance is superimposed onto the current control signal of the proportional valve, and the current response characteristics of the valve port are extracted. The current response characteristics are compared with the baseline response data to calculate the valve port contamination identification index. Based on the valve port contamination identification index, the controller determines the valve port contamination status and whether to trigger a self-cleaning action. When a self-cleaning action is triggered, the controller controls the proportional valve to perform the self-cleaning action through valve core jitter, short-duration large-opening pulses, or rapid pressure relief. After one round of self-cleaning action, a detection disturbance is applied again. The cleaning effect is verified based on the post-cleaning contamination identification index and the contamination improvement rate before and after cleaning, and it is determined whether to perform multiple self-cleaning actions. The storage unit is used to store the baseline response data, contamination status judgment threshold, and self-cleaning action control parameters of the proportional valve in the clean state.

10. The online identification and self-cleaning system for contamination at the valve port of a miniature proportional valve as described in claim 9, characterized in that, The controller is also used to monitor the valve downstream pressure, coil current and unblocking duration in real time during the unblocking process. When any of the following conditions are met, the unblocking action is stopped immediately.

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