Integrated vacuum pump testing method

Abstract

The invention relates to the technical field of equipment test methods, in particular to an integrated vacuum pump test method which comprises the following steps: establishing an adsorption saturation state in a closed test cavity, including filling mixed gas into the test cavity, controlling the temperature of the cavity wall of the test cavity to be gradually reduced, and enabling gas molecules to be adsorbed on the inner wall of the cavity; applying a sudden load to the tested vacuum pump, namely starting the vacuum pump and triggering an infrared heating module at the same time, so that the temperature of the wall of the test cavity is increased to a preset temperature at a preset heating rate; the desorption dynamic parameters are collected to generate desorption characteristic values, the gas release amount in the desorption process is monitored in real time, the desorption time constant and the average vacuum degree are combined, and the adsorption gas release rate is calculated. According to the method, the evaluation accuracy and the result repeatability of the weak gas treatment performance of the vacuum pump are improved, and the method is suitable for quality detection and dynamic performance comparative analysis of a high-sensitivity vacuum device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of device testing method, and particularly relates to an integrated vacuum pump testing method. BACKGROUND

[0002] As a key component in high vacuum system, the pumping capacity of vacuum pump directly affects the ultimate vacuum degree and stable operation performance of the whole system. The existing vacuum pump performance testing method mainly relies on steady-state pumping speed measurement or ultimate vacuum degree determination, often ignoring the response characteristics of the vacuum pump to weak release sources such as adsorbed gas and condensed water, and is difficult to fully reflect the actual pumping capacity of the vacuum pump under non-steady-state load conditions.

[0003] In the gas adsorption-desorption related performance test, the traditional scheme usually adopts liquid nitrogen cold trap to cool the wall surface to form an adsorption layer, and then releases the adsorbed gas by natural warming. However, this method has the problems of uncontrollable cooling rate, desorption triggering lag, uneven temperature distribution and difficult process synchronization, resulting in large fluctuation of test results. At the same time, there is a lack of high-resolution data acquisition and quantitative indicators in the desorption process, which cannot accurately evaluate the response behavior of the vacuum pump to transient load.

[0004] In addition, the existing method generally relies on manual judgment of adsorption equilibrium and desorption end time, lacks dynamic criteria and statistical effectiveness determination mechanism, and thus the test process relies on experience and lacks reproducibility. SUMMARY

[0005] The present application provides an integrated vacuum pump testing method, which can accurately depict the dynamic performance of the vacuum pump by spatiotemporal coordinated loading and real-time data analysis in a controllable adsorption environment.

[0006] An integrated vacuum pump testing method, comprising the following steps:

[0007] S1, establishing an adsorption saturation state in a closed test cavity, including filling the test cavity with mixed gas, and gradually reducing the cavity wall temperature of the test cavity to make the gas molecules adsorb on the inner wall of the cavity;

[0008] S2, applying a sudden load to the vacuum pump to be tested, including starting the vacuum pump and triggering the infrared heating module at the same time, so that the temperature of the cavity wall of the test cavity rises at a predetermined temperature rising rate to a predetermined temperature;

[0009] S3, collecting desorption dynamic parameters to generate desorption characteristic values, including real-time monitoring of the gas release amount in the desorption process, and calculating the adsorbed gas release rate η in combination with the desorption time constant and the average vacuum degree.

[0010] Optionally, S1 specifically comprises:

[0011] S11, filling the closed test cavity with nitrogen and water vapor mixed gas with a volume ratio of 3:1 through a multi-channel gas distribution system, and controlling the gas pressure in a preset range;

[0012] S12, starting the semiconductor refrigeration module to reduce the temperature of the inner wall of the cavity from room temperature to-35℃ at a step rate, and maintaining the current temperature;

[0013] S13, when the fluctuation amplitude of the vacuum degree monitoring value of the cavity is less than a predetermined fluctuation threshold, it is determined that the adsorption saturation state is reached.

[0014] Optionally, the fluctuation amplitude of the vacuum degree monitoring value in S13 is calculated as:

[0015] wherein, is the change amplitude of the vacuum degree in unit time, P(t) is the cavity vacuum degree reading at time t, and 10 min is the time window;

[0016] The predetermined fluctuation threshold is set to 0.15 kPa / 10 min;

[0017] When the fluctuation amplitude of the cavity vacuum degree monitoring value in unit time meets the following condition:

[0018] And when this condition is continuously established for three times, it is determined that the adsorption saturation state is reached in the test cavity, and "continuously established for three times" means that the fluctuation condition meets less than 0.15 kPa in at least three adjacent time windows.

[0019] Optionally, the multi-channel gas distribution system is used to fill the mixed gas composed of nitrogen and water vapor into the closed test cavity, specifically including:

[0020] Nitrogen channel: including a nitrogen gas source and a mass flowmeter;

[0021] Water vapor channel: including an ultrasonic atomized water vapor generator and an atomization rate control valve, the atomization rate control valve adjusts the atomization flow according to the target output ratio;

[0022] Gas mixing chamber: the nitrogen and water vapor are fully mixed in the gas mixing chamber, and the mixing chamber adopts a stainless steel pipe type static mixer.

[0023] Proportional feedback control module: real-time acquisition of flow information of nitrogen and water vapor channels and cavity pressure data; adjusting the mass flowmeter and the atomization rate control valve through the proportional-integral-derivative algorithm in the main controller to ensure that the volume ratio of the mixed gas is controlled at 3:1.

[0024] Optionally, S2 specifically includes:

[0025] S21, trigger the annularly distributed infrared heating module while sending a start signal to the measured vacuum pump;

[0026] S22, raise the temperature of the inner wall of the test cavity from-35℃ to 65℃ at a rate of 12-15℃ / s through infrared radiation of a preset wavelength;

[0027] S23, collect the cavity wall temperature of the test cavity in real time through the thermocouple array, and calculate the temperature gradient of the cavity wall of the test cavity, and when the maximum local temperature difference is greater than the maximum temperature threshold, start the compensation heater for temperature equalization control.

[0028] Optionally, the infrared heating module adopts multiple groups of infrared heaters arranged in a ring shape, and the radiation wavelength covers 2.5-4.0μm.

[0029] Optionally, the maximum local temperature difference is calculated as: ΔT max =max(T i )-min(T i ), i=1, 2,..., 16; when ΔT max >8℃, start the regional compensation heater, and dynamically adjust the compensation power according to the temperature difference of each region:

[0030]

[0031] wherein T i is a temperature value measured by the i th thermocouple, is the average value of the current 16-point temperature, ΔT max is the maximum temperature difference in the real-time temperature distribution of the cavity wall, represents the output power of the i th regional compensation heater.

[0032] Optionally, the S3 specifically comprises:

[0033] S31, monitor the gas release amount ΔQ of the desorption process in real time through the quadrupole mass spectrometer;

[0034] S32, record the vacuum degree change curve by using the capacitive diaphragm vacuum gauge, and extract the desorption time t corresponding to the time constant τ;

[0035] S33, calculate the average vacuum degree P m ;

[0036] S34, output the desorption gas release rate according to the desorption gas release rate calculation formula, and determine the data to be valid when the standard deviation of the η value calculated for multiple times is less than the data validity standard deviation threshold.

[0037] Optionally, the gas release amount ΔQ is calculated as:

[0038]

[0039] wherein k is a cavity volume calibration coefficient, A i is the peak area of the mass number 18 corresponding to the i-th sampling, A bas is the background baseline area of the mass channel, and n is the number of sampling in the desorption process.

[0040] Optionally, the adsorbed gas release rate calculation formula is represented as:

[0041] The present application has the following beneficial effects:

[0042] The vacuum pump test method provided by the present application can form a stable adsorption layer in a controlled low-temperature environment, induce gas desorption by synchronously loading high-energy infrared rapid heating and vacuum pumps, and extract key characteristic parameters such as desorption release rate by combining mass spectrometry and vacuum degree dual-channel dynamic collection. The method has the advantages of fast temperature response, good temperature field uniformity, high gas release amount detection precision, and clear characteristic criterion quantification, and improves the evaluation accuracy and result repeatability of the weak gas treatment performance of the vacuum pump, and is suitable for mass detection and dynamic performance comparison analysis of high-sensitivity vacuum devices.

[0043] The present application precisely fills the mixed gas with a nitrogen and water vapor volume ratio of 3:1 into a closed test cavity through a multi-channel gas distribution system, and reduces the cavity wall temperature in a stepwise temperature control manner by using a semiconductor refrigeration module to form a stable adsorption saturation layer. At the same time, the desorption is dynamically judged to be stable by using the vacuum degree fluctuation threshold as the criterion, which breaks through the traditional non-deterministic problem of relying on fixed time judgment, and ensures that the starting point of the subsequent desorption process is consistent and the data has good repeatability.

[0044] The present application uses an infrared heating module distributed in a ring shape, which is triggered synchronously at the moment of vacuum pump startup to rapidly heat the cavity wall surface with infrared radiation of a predetermined wavelength, optimizes the desorption kinetics process of ice crystals, and constructs a temperature field monitoring network combined with a thermocouple array. When a local temperature difference greater than a temperature threshold is detected, a partition compensation heater is automatically enabled to realize active uniform temperature control, which significantly reduces desorption delay, local saturation deviation and other phenomena caused by uneven temperature field.

[0045] The present application uses a capacitance diaphragm vacuum gauge to extract the time point corresponding to the vacuum response time constant τ as the desorption duration t, integrates a quadrupole mass spectrometer to collect the gas release amount ΔQ at a high frequency, and combines integral calculation of the average vacuum degree P to output the desorption characteristic parameter η. To ensure the result reliability, the standard deviation of η value in 3 independent experiments is used as an effectiveness threshold to construct a multi-index fusion system for evaluating the desorption performance, which improves the quantification ability and data stability of the test system. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description only illustrate the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0047] Fig. 1 The test method flowchart of the embodiment of the present application is shown in the figure.

[0048] Fig. 2 The mixed gas formation schematic diagram of the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0049] The present application will be described in detail below with reference to the drawings and specific embodiments. For some known technologies, other alternative ways can also be implemented by those skilled in the art; and the drawings are only used to more specifically describe the embodiments and are not intended to specifically limit the present application.

[0050] As shown in the figure, an integrated vacuum pump test method comprises the following steps: Figs. 1-2

[0051] S1, establishing an adsorption saturation state in a closed test cavity, comprising filling the test cavity with mixed gas, gradually reducing the cavity wall temperature of the test cavity, and adsorbing gas molecules on the inner wall of the cavity;

[0052] S2, applying a sudden load to the vacuum pump under test, comprising starting the vacuum pump while triggering the infrared heating module, so that the cavity wall temperature of the test cavity rises at a predetermined temperature rise rate to a predetermined temperature;

[0053] S3, collecting desorption dynamic parameters to generate desorption characteristic values (release rate), comprising real-time monitoring of the gas release amount during the desorption process, combining the desorption time constant and the average vacuum degree, and calculating the adsorbed gas release rate η. The η value essentially represents the adsorbed gas release rate under unit vacuum pressure, and the larger the value is, the stronger the material surface adsorption is and the worse the vacuum pump anti-interference ability is.

[0054] The closed test cavity is an analog working condition environment cabin independent of the vacuum pump under test, which is specially used to simulate the gas adsorption-desorption environment of the vacuum pump in actual work, and is sealed connected with the gas inlet of the vacuum pump under test through a flange interface. The mixed gas injection and the infrared heating module both act on the closed test cavity.

[0055] ​The integrated test method of the application integrates the adsorption environment construction, the sudden load application, the infrared temperature control, the vacuum degree and the gas release amount synchronous collection, the characteristic parameter calculation and the data validity judgment in the same closed loop test process, the parts are interlinked, unified and coordinated, the problems of dispersion, dependence on multiple devices and manual judgment in the traditional test are avoided, and the integration of the test system structure and function is realized.

[0056] S1 specifically comprises:

[0057] S11, filling the closed test cavity with nitrogen and water vapor mixed gas with a volume ratio of 3:1 through a multi-channel gas distribution system, controlling the total gas pressure P g stabilized in the interval of 50kPa-80kPa.

[0058] S12, starting the semiconductor refrigeration module to control the cavity inner wall temperature T wall decreased from room temperature to-35℃ at a rate of ≤5℃ / min.

[0059] S13, real-time monitoring of the cavity vacuum degree P(t), when the vacuum degree change in unit time meets the following conditions:

[0060] and the condition is continuously established for three times, it is determined that the adsorption saturation state is reached in the test cavity.

[0061] wherein, P g is the stable pressure of the mixed gas in the cavity, T wall is the test cavity inner wall temperature, P(t) is the cavity vacuum degree reading at time t, is the change amplitude of the vacuum degree in unit time; "continuous establishment for three times" means that the above fluctuation condition meets less than 0.15kPa in at least three adjacent time windows (10 minutes as a unit).

[0062] The multi-channel gas distribution system is used to accurately fill the mixed gas composed of nitrogen and water vapor into the closed test cavity, which specifically comprises the following:

[0063] nitrogen channel: including a high-purity nitrogen gas source and a mass flow meter, the nitrogen gas source provides high-purity nitrogen; the mass flow meter is used for precision adjustment and real-time monitoring of the nitrogen flow, has a digital control interface, and can interact with the main control system and realize closed-loop feedback control.

[0064] Water vapor channel: including an ultrasonic atomized water vapor generator and an atomization rate control valve, the water vapor generator has a working frequency of 1.7MHz and is used to atomize deionized water into water vapor with a particle size of less than 5μm; the atomization rate control valve adjusts the atomization flow according to the target output ratio; the control valve communicates with the main control system to realize the adjustment of the atomization intensity by adjusting the water supply rate and the driving frequency.

[0065] Gas mixing chamber: Nitrogen and water vapor are thoroughly mixed in the gas mixing chamber, which uses a stainless steel pipe static mixer.

[0066] Proportional feedback control module: Includes gas proportional acquisition module, host controller, and feedback adjustment unit, which acquires real-time flow information and cavity pressure data of nitrogen and water vapor channels; adjusts MFC and atomization rate control valve through proportional-integral-derivative (PID) algorithm in host controller to ensure that the volume ratio of mixed gas is stably controlled at 3:1; when the mixing ratio or cavity pressure deviates from the set value, automatically corrects the output of each channel to realize dynamic closed-loop control.

[0067] The following is a specific scheme for how the PID control algorithm in the proportional feedback control system adjusts the mass flow meter (MFC) and the atomization rate control valve to maintain the volume ratio of the nitrogen and water vapor mixed gas at 3:1:

[0068] I. Control objective: Set the target volume ratio as: Where, represents the real-time volume flow of the nitrogen channel, measured by the MFC, is the equivalent volume flow of the water vapor channel, estimated by the atomization rate control valve.

[0069] II. Error definition:

[0070] The real-time mixing ratio is:

[0071] The error is defined as: e(t) = R target - R(t);

[0072] III. PID control formula

[0073] The adjustment signal u(t) of the PID controller to the MFC output or the atomization valve input is calculated as:

[0074]

[0075] Where, K p is the proportional gain, which adjusts the system response speed, K i is the integral gain, which eliminates steady-state error, and K d is the derivative gain, which suppresses error oscillation, and u(t) is the control output signal, which can be used to adjust:

[0076] the nitrogen MFC opening (if the water vapor flow is stable);

[0077] or the driving frequency / supply rate of the atomization rate control valve (if the nitrogen flow is the reference).

[0078] IV. Application logic:

[0079] Real-time collection and

[0080] Calculate the actual mixing ratio R(t) and the error e(t);

[0081] The error is input into the PID controller to generate the adjustment signal u(t);

[0082] The controller outputs new set values ​​to the MFC and / or atomizing valve according to the regulation strategy;

[0083] The control period is typically set to 0.5 to 1.0 seconds to ensure dynamic stability of the mixing ratio.

[0084] The semiconductor refrigeration module is used to reduce the temperature of the inner wall of the sealed test chamber from room temperature to -35°C at a controlled rate, achieving a controllable step-by-step cooling process to promote the uniform formation of the adsorption layer. It mainly includes the following parts:

[0085] 1. Thermoelectric cooler: including a multi-stage Peltier array, preferably a five-stage low-temperature cascade type (Laird CP5-127 series or equivalent custom device);

[0086] 2. Temperature control drive circuit module: A closed-loop constant current driver composed of a PWM modulation chip and a high-power MOS tube receives temperature setting instructions from the main control system, adjusts the operating voltage of the thermoelectric cooler in real time, and realizes step-by-step temperature control rate setting;

[0087] 3. Temperature sensing and feedback: The sensor type is PT1000 thin film thermistor, which is installed at the four corners and bottom of the cavity to form a temperature sampling matrix, realizing temperature closed-loop control and temperature gradient monitoring, ensuring precise segmentation of temperature drop rate, and meeting the requirements of ice crystal control and adsorption stratification.

[0088] 4. Cooling system:

[0089] Hot end cooling method: liquid cooling circulation system + high-efficiency heat exchanger, or forced air cooling fin group;

[0090] Liquid cooling configuration: microchannel cold plate + coolant pump + heat exchanger;

[0091] Maintain stable heat dissipation at the hot end of the thermoelectric cooler to avoid heat accumulation causing performance degradation at the cold end.

[0092] S2 specifically includes:

[0093] S21, when the vacuum pump under test is started, a synchronous trigger signal is sent to the annularly distributed infrared heating modules, triggering the infrared heating modules to emit infrared radiation with a wavelength of 2.5-4 μm.

[0094] S22, temperature T of inner wall of test cavity is heated by infrared radiation wall (t) is the rate of temperature rise of the inner wall of the cavity, from the initial temperature of -35℃ to 65℃, wherein the temperature rise stage includes the ice crystal phase transition interval.

[0095] S23, temperature distribution is collected in real time by 16-point thermocouple array installed on the inner wall of the cavity, and the maximum local temperature difference ΔT is calculated: max = max(T i )-min(T i ), i = 1, 2, …, 16; when ΔT max > 8℃, the regional compensation heater is started, and the compensation power is dynamically adjusted according to the temperature difference of each region:

[0096]

[0097] T wall (t) represents the temperature of the inner wall of the cavity at a certain time, represents the temperature rise rate of the cavity wall, T i is the temperature value measured by the i-th thermocouple, is the average value of the current 16-point temperature, ΔT max is the maximum temperature difference in the real-time temperature distribution of the cavity wall, represents the output power of the i-th regional compensation heater.

[0098] The “ice crystal phase transition interval” refers to the temperature range in which ice crystals change from solid to liquid (i.e. melt) during temperature rise. In this interval, the substance undergoes a phase transition process, which is characterized by the fact that although the temperature continues to rise, the energy is mainly used to destroy the ice crystal structure (overcome lattice binding energy), rather than rapidly raising the temperature. For solid-state systems containing adsorbed water molecules (ice layer or microcrystalline water molecules adsorbed on the cavity wall), this process is usually accompanied by structural loosening and enhanced water desorption. In the vacuum test cavity, this stage is the key temperature range with the most active desorption behavior.

[0099] The infrared heating module uses an infrared heater with 6 groups of silicon carbide radiators arranged in a ring shape, with a single group power of 2.4kW, and the radiation wavelength covers 2.5–4.0μm;

[0100] Spectrum distribution:

[0101] 2.5–3.0μm: 45% for exciting surface adsorbed water molecules;

[0102] 3.0–3.5μm: 38% for penetrating the ice crystal layer to promote desorption;

[0103] 3.5–4.0μm: 17% for maintaining the substrate temperature.

[0104] The S3 specifically includes:

[0105] S31, use a quadrupole mass spectrometer to monitor the gas release ΔQ in real time during the desorption process, with a sampling frequency of not less than 100 Hz, and calculate the release amount by digital integration:

[0106]

[0107] Where, k is the cavity volume calibration coefficient (if the cavity is 5L, k = 0.078), A i is the mass number corresponding to the i-th sampling The peak area, A base is the background baseline area of ​​the mass channel, and n is the number of sampling times during the desorption process.

[0108] S32, using a capacitance film vacuum gauge to record the vacuum degree change curve, extracting the desorption time t corresponding to the characteristic time constant τ, where τ is defined as:

[0109] τ=twhenP(t)=P0-0.632·(P0-P e );

[0110] Among them, P0 is the initial vacuum degree at the moment of heating start (Pa), P e is the stable value of vacuum degree, when The vacuum degree at that moment is taken as P(t), P(t) is the vacuum degree reading at time t, and τ is the time constant of the system vacuum response, which is actually used to define the desorption time.

[0111] "0.632" is a standard mathematical constant derived from the first-order exponential decay model. Its application in describing the vacuum desorption process reflects the definition of the characteristic time constant τ of the desorption dynamics. In the physical system (including vacuum degree, temperature, pressure, etc.), the dynamic response of the first-order system can be described by the following exponential form: P(t) = P e +(P0-P e )·e -t / τ ; When t = τ, the above formula becomes:

[0112] P(τ)=P e +(P0-P e )·e -1 =P e +(P0-P e )·0.368;

[0113] Therefore: P(τ)=P0-0.632·(P0-P e ); This means that when the system changes from P0 to P eThe time taken to reach 63.2% of the total change, defined as the time constant τ.

[0114] S33, calculate the average vacuum P m The integral average is defined as:

[0115] Where t is the desorption time extracted from τ, and P(τ) is the function of the change in vacuum over time in the time interval [0, t].

[0116] S34, output the adsorbed gas release rate η according to the following formula:

[0117] Further, when the standard deviation σ of the η value calculated by three consecutive tests is less than 0.02, the group of data is determined to be valid: η <0.02, it is determined that the group of data is valid:

[0118]

[0119] Where η i is the adsorbed gas release rate calculated in the i-th time, N u is the average of the three calculation results, and N

[0120] The present application encompasses any alternative, modification, equivalent method and scheme made on the essence and scope of the present application. In order to make the public have a thorough understanding of the present application, specific details are described in the following preferred embodiments of the present application, and the present application can also be fully understood without the description of these details to those skilled in the art. In addition, in order to avoid unnecessary confusion to the essence of the present application, well-known methods, processes, procedures, elements and circuits, etc. are not described in detail.

[0121] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should be considered as the protection scope of the present application.

Claims

1. An integrated vacuum pump testing method, characterized in that: The following steps are involved: S1, establishing an adsorption saturation state in a sealed test chamber, including filling the test chamber with a mixed gas and controlling the temperature of the chamber wall to gradually decrease so that the gas molecules are adsorbed on the chamber inner wall; S2, applying a sudden load to the vacuum pump under test, including starting the vacuum pump and triggering the infrared heating module at the same time, so that the temperature of the test cavity wall rises to a predetermined temperature at a predetermined heating rate; S3, collecting desorption dynamic parameters to generate desorption characteristic values, including real-time monitoring of the gas release amount during the desorption process, and calculating the adsorbed gas release rate in combination with the desorption time constant and the average vacuum degree.

2. The integrated vacuum pump testing method according to claim 1, characterized in that: Said S1 specifically includes: S11, filling the sealed test chamber with a mixture of nitrogen and water vapor in a volume ratio of 3:1 through a multi-channel gas distribution system, and controlling the gas pressure within a preset range; S12, start the semiconductor refrigeration module to reduce the temperature of the inner wall of the cavity from room temperature to -35°C at a step rate, and maintain the current temperature; S13, when the fluctuation amplitude of the chamber vacuum monitoring value is less than a predetermined fluctuation threshold, it is determined that the adsorption saturation state has been reached.

3. The integrated vacuum pump testing method according to claim 2, characterized in that: The fluctuation range of the vacuum monitoring value in S13 is calculated as: in, is the variation of vacuum degree per unit time, P(t) is the vacuum degree reading of the cavity at time t, and 10 minutes is the time window; The predetermined fluctuation threshold is set to 0.15 kPa / 10 min; When the fluctuation amplitude of the cavity vacuum monitoring value per unit time meets the following conditions: When this condition is met three times in a row, it is determined that the adsorption saturation state has been reached in the test chamber. "Three times in a row" means that the fluctuation condition is less than 0.15kPa in at least three adjacent time windows.

4. The integrated vacuum pump testing method according to claim 3, characterized in that: The multi-channel gas distribution system is used to fill a gas mixture consisting of nitrogen and water vapor into the closed test chamber, specifically including: Nitrogen channel: including nitrogen gas source and mass flow meter; Water vapor channel: includes an ultrasonic atomizing water vapor generator and an atomization rate control valve, wherein the atomization rate control valve adjusts the atomization flow rate according to the target output ratio; Gas mixing chamber: The nitrogen and water vapor are fully mixed in the gas mixing chamber, and the mixing chamber adopts a stainless steel tubular static mixer; Proportional feedback control module: collects flow information and cavity pressure data of nitrogen and water vapor channels in real time; adjusts the mass flow meter and atomization rate control valve through the proportional-integral-differential algorithm in the main controller to ensure that the volume ratio of the mixed gas is controlled at 3:

1.

5. The integrated vacuum pump testing method according to claim 1, characterized in that: The S2 specifically includes: S21, sending a start signal to the vacuum pump under test and triggering the annularly distributed infrared heating modules; S22, using infrared radiation of a preset wavelength, the temperature of the inner wall of the test chamber is raised from -35°C to 65°C at a rate of 12-15°C / s; S23, collect the test cavity wall in real time through the thermocouple array, and calculate the temperature gradient of the test cavity wall. When the maximum local temperature difference reaches the maximum temperature threshold, start the compensation heater to perform temperature balance control.

6. The integrated vacuum pump testing method according to claim 5, characterized in that: The infrared heating module uses multiple groups of infrared heaters arranged in a ring shape, and the radiation wavelength covers 2.5-4.0 μm.

7. The integrated vacuum pump testing method according to claim 5, characterized in that: The maximum local temperature difference is calculated as: ΔT max =max(T i )-min(T i ),i=1,2,...,16; when ΔT max When the temperature is >8℃, the regional compensation heater is started and the compensation power is dynamically adjusted according to the temperature difference in each area: Among them, T i is the temperature value measured by the i-th thermocouple, is the average temperature of the current 16 points, ΔT max is the maximum temperature difference in the real-time temperature distribution of the cavity wall, represents the output power of the compensation heater in the i-th zone.

8. The integrated vacuum pump testing method according to claim 1, characterized in that: The S3 specifically includes: S31, real-time monitoring of the gas release ΔQ during the desorption process by a quadrupole mass spectrometer; S32, using a capacitance film vacuum gauge to record the vacuum degree change curve and extracting the desorption time t corresponding to the time constant τ; S33, calculate the average vacuum degree P m ; S34, outputting the adsorbed gas release rate according to the adsorbed gas release rate calculation formula, and determining that the data is valid when the standard deviation of the η value calculated multiple times in a row is less than the data validity standard deviation threshold.

9. The integrated vacuum pump testing method according to claim 8, characterized in that: The gas release amount ΔQ is calculated as: Where k is the cavity volume calibration coefficient, A i is the peak area of ​​mass number 18 corresponding to the i-th sampling, A base is the background baseline area of ​​the mass channel, and n is the number of sampling times during the desorption process.

10. The integrated vacuum pump testing method according to claim 9, characterized in that: The adsorbed gas release rate calculation formula is expressed as:

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