CN115025690A - Monodisperse ultrafine particle stable generation device and method based on double closed-loop control - Google Patents

Monodisperse ultrafine particle stable generation device and method based on double closed-loop control Download PDF

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CN115025690A
CN115025690A CN202210461153.0A CN202210461153A CN115025690A CN 115025690 A CN115025690 A CN 115025690A CN 202210461153 A CN202210461153 A CN 202210461153A CN 115025690 A CN115025690 A CN 115025690A
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electrospray
current
loop control
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CN115025690B (en
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余同柱
康士鹏
杨义新
桂华侨
吉喆
王计广
陈大仁
刘建国
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Hefei Institutes of Physical Science of CAS
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F33/00—Other mixers; Mixing plants; Combinations of mixers
    • B01F33/05—Mixers using radiation, e.g. magnetic fields or microwaves to mix the material
    • B01F33/052—Mixers using radiation, e.g. magnetic fields or microwaves to mix the material the energy being electric fields for electrostatically charging of the ingredients or compositions for mixing them
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/20—Measuring; Control or regulation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/20—Measuring; Control or regulation
    • B01F35/21—Measuring
    • B01F35/211—Measuring of the operational parameters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/20—Measuring; Control or regulation
    • B01F35/21—Measuring
    • B01F35/212—Measuring of the driving system data, e.g. torque, speed or power data
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/20—Measuring; Control or regulation
    • B01F35/22—Control or regulation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/20—Measuring; Control or regulation
    • B01F35/22—Control or regulation
    • B01F35/221—Control or regulation of operational parameters, e.g. level of material in the mixer, temperature or pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/30—Driving arrangements; Transmissions; Couplings; Brakes
    • B01F35/32—Driving arrangements
    • B01F35/32005—Type of drive
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/71—Feed mechanisms
    • B01F35/717—Feed mechanisms characterised by the means for feeding the components to the mixer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/71—Feed mechanisms
    • B01F35/717—Feed mechanisms characterised by the means for feeding the components to the mixer
    • B01F35/7179—Feed mechanisms characterised by the means for feeding the components to the mixer using sprayers, nozzles or jets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/80—Forming a predetermined ratio of the substances to be mixed
    • B01F35/83—Forming a predetermined ratio of the substances to be mixed by controlling the ratio of two or more flows, e.g. using flow sensing or flow controlling devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/0095—Preparation of aerosols

Abstract

The invention relates to a device and a method for stably generating monodisperse ultrafine particles based on double closed-loop control. The invention is characterized in that the working current of the electrospray module is controlled to be stabilized at a certain set value, the control system can collect and process the working current of the electrospray module and the image of the droplet at the tip of the capillary spray needle, the current measured value and the image signal are taken as the feedback quantity of the control system, and the working state of the electrospray module is adjusted by the high-voltage adjusting module after the calculation of the control system so as to adjust the working current of the electrospray module. The generated current is easy to be influenced by external factors, and the device can monitor and maintain the stable work of the electrospray module so as to stably generate monodisperse ultrafine particles.

Description

Monodisperse ultrafine particle stable generation device and method based on double closed-loop control
Technical Field
The invention relates to the technical field of aerosol science, in particular to a device and a method for stably generating monodisperse ultrafine particles based on double closed-loop control.
Background
In the field of aerosol science, monodisperse aerosols with adjustable particle size and composition are generally generated by the electrospray technique. On one hand, the method can provide samples for further researching the physical and chemical properties of aerosol with specific particle size and specific components, such as the suction growth characteristic research; on the other hand, the high-concentration monodisperse aerosol sample is also an important component in the calibration system of the aerosol measuring instrument. In addition, electrospray has wide application in fuel atomization, thin film deposition, electrospray ionization mass spectrometry, and drug development.
Generally, electrospray operating current stabilization is an indicator that electrospray is operating stably and producing a stable amount of charge on the resulting droplets. The operating current and the operating state of electrospray are determined by many factors, such as the physical properties of the spray solution (i.e., conductivity, surface tension, viscosity, etc.), the injection rate of the spray solution, the spray voltage, the distance between the outlet of the capillary and the high voltage electrode, etc. In addition to the above factors, the stability of electrospray operation and the quality of the generated particulate matter may also be affected by unexpected factors, such as drift in spray solution conductivity due to temperature, the presence of bubbles in the spray solution, and the like. Therefore, the current shift of the electrospray inevitably occurs during long-term operation, and closed-loop control needs to be added to the working current in the electrospray system. In order to keep the spraying process stable in long-term operation, the invention introduces a new feedback quantity and the shape of the liquid drop at the tip of the capillary spray needle into a control system so as to improve the stability of the control system, assist the current control of the electrospray and stably generate monodisperse ultrafine particles for a long time.
Disclosure of Invention
The invention provides a monodisperse ultrafine particle stable generating device based on double closed-loop control, which can solve the technical problems and realize long-term stable generation of monodisperse ultrafine particles.
In order to achieve the purpose, the invention adopts the following technical scheme:
a stable generating device of monodisperse ultrafine particles based on double closed-loop control comprises an electrospray module and a double closed-loop control system, wherein the double closed-loop control system comprises an electrospray module, a current measurement module, an image acquisition module, a high-voltage module and a logic operation module;
the electrospray module comprises a microsyringe, a spray cavity, a capillary spray needle, an air and carbon dioxide inlet, a high-voltage electrode and a soft X-ray neutralizer; the microsyringe is connected with the capillary spray needle through a 1/32' tube; the air inlet and the carbon dioxide inlet penetrate through the spraying cavity and ensure the air tightness with the spraying cavity; the high-voltage electrode is arranged opposite to the capillary spray needle and is not contacted with the capillary spray needle; the soft X-ray neutralizer is arranged outside the spray cavity;
the current measuring module comprises a current-voltage conversion circuit, a voltage follower and an analog-digital signal converter; the current-voltage conversion circuit comprises a conversion resistor and a filter capacitor, one end of the conversion resistor and the filter capacitor is connected in parallel and then is connected to the capillary spray needle through a wire, and the other end of the conversion capacitor is grounded; the voltage follower is composed of an operational amplifier, the input end of the voltage follower is connected to the capillary spray needle through a lead, and the output end of the voltage follower is connected to the input end of the analog-digital signal converter through a lead; the output end of the analog-digital signal converter is connected to the logic operation module through a lead;
the image acquisition module comprises a CCD camera-micro lens and programmable array logic; the CCD camera-microscope lens is arranged on the outer side of the spray cavity, and the digital signal output end of the CCD camera is connected to the programmable array logic through a lead; the programmable array logic is connected to the logic operation module through a serial port line;
the high-voltage module comprises a digital-analog signal converter and a high-voltage source; the input end of the digital-analog signal converter is connected with the logic operation module through a lead, and the output end of the digital-analog signal converter is connected to the input end of a high voltage source through a lead; the output end of the high voltage source is connected to the high voltage electrode through a high voltage resistant lead.
Furthermore, the material of a spraying cavity in the single-capillary spraying needle electrospray module is organic glass.
Further, the logic operation module comprises a single chip microcomputer.
Furthermore, the electrospray module still includes the metal protective housing, the metal protective housing is installed in soft X ray neutralizer opposite, prevents that soft X ray from revealing.
On the other hand, the invention also comprises a method for stably generating the monodisperse ultrafine particles based on the double closed-loop control system, and the device for stably generating the monodisperse ultrafine particles based on the double closed-loop control is characterized by comprising the following steps:
when the high-voltage electrode does not apply voltage, the microsyringe conveys the solution with conductivity into the spraying cavity at a set speed through the capillary spray needle, the solution is blown away by air and carbon dioxide to form small droplets, and the small droplets leave the spraying cavity after passing through the soft X-ray irradiation area along with the air flow; the voltage on the high-voltage electrode is controlled by the high-voltage module, and along with the gradual rise of the voltage on the high-voltage electrode to a set range, the solution leaves the capillary spray needle in a conical jet flow mode to form charged liquid drops with uniform size; the charged droplets enter the soft X-ray irradiation area along with the air flow, the charge is neutralized, the droplet solution volatilizes in the flight process, and the residual solute forms electrically neutral monodisperse particles.
Furthermore, the shapes of the top end of the capillary spray needle and the top end liquid drop are shot by a CCD camera-micro lens, and the image is transmitted to the FPGA in a digital signal form to judge whether conical jet flow is formed or not; if the jet flow is the conical jet flow, the FPGA calculates the vertex angle of the conical jet flow and then transmits the vertex angle to the logic operation module.
In another aspect, the invention discloses a method for stably generating monodisperse ultrafine particles based on a double closed-loop control system, which comprises the following steps:
s1, manually setting the inlet flow of clean air and carbon dioxide, manually setting the inlet flow of a solution to be generated, automatically linearly increasing the voltage by a logic operation module, continuously judging whether an electrospray module works in a conical jet mode, stopping high-pressure change to stabilize working current and droplet shape if the electrospray module works in the conical jet mode, setting target current and entering double closed loop control to maintain the working current stability of the electrospray module;
s2, the original color RGB image obtained by the image acquisition module contains complete liquid drops; the color RGB image is subjected to monochrome gray scale conversion and binarization processing to obtain a black-white image, and is subjected to Sobel edge detection algorithm processing to obtain a capillary spray needle tip-liquid drop profile; the FPGA analyzes the contour shape to judge whether the electrospray module works in a conical jet flow mode, if so, the shape of the liquid drop is quantized through the contour, and the vertex angle of the conical liquid drop is calculated to be transmitted to the logic operation module for next calculation;
s3, the logic operation module includes two input signals: the electrospray working current obtained by the current measuring module and the liquid drop profile obtained by the image acquisition module; the logic operation module comprises an output signal: a voltage regulation instruction is sent to the high-voltage module; the double closed-loop control system realized by the logic operation module changes the output voltage by calculating and analyzing two input signals so as to adjust the working current of the electrospray to the target current and realize the stable operation of the electrospray;
s4, the logic operation module makes a difference between the target current and the measured value of the working current to perform outer loop proportional-integral-differential operation; the operation result is converted into a liquid drop shape target, and the liquid drop shape target is subtracted from the liquid drop shape measurement value to perform inner ring PID operation; the operation result is converted into a voltage regulation instruction and then applied to the high-voltage electrode; after double closed-loop control, the current of the electric spraying module converges to a set value, and monodisperse ultrafine particles are generated stably.
The double closed-loop control system aims to control the working current of the electric spraying module to be stable at a certain set value (the current stability is a main mark for the electric spraying module to stably generate monodisperse ultrafine particles). The control system can collect and process the working current of the electrospray module and the image of the liquid drop at the tip of the capillary spray needle, the current measured value and the image signal are used as feedback quantity of the control system, and the working state of the electrospray module is adjusted through the high-voltage adjusting module after the current measured value and the image signal are calculated by the control system so as to adjust the working current of the electrospray module. In long-time work, the generated current is easily interfered by external factors such as air pressure and temperature, and the device can monitor and maintain the stable work of the electrospray module so as to stably generate monodisperse ultrafine particles.
Compared with the prior art, the invention has the following beneficial effects:
(1) the double closed-loop control system realizes the control of the working current of the electrospray, and solves the problem that the quality of generated particles is influenced because the current is easy to change during the long-time operation of the electrospray.
(2) The double closed-loop control system introduces a new feedback quantity: capillary needle tip solution shape. In the high-frequency voltage change, the control system takes the shape of the solution at the tip of the capillary spray needle with better open-loop characteristic as a control target, so that the stability of the control system is improved.
(3) The method for generating the monodisperse particles can realize automatic starting of the electrospray system, automatic adjustment of the conical jet flow mode and automatic control of the working current, and simplifies the operation of the electrospray system.
Drawings
FIG. 1 is a schematic diagram of a particle generating apparatus and a control system thereof according to the present invention;
FIG. 2 is an enlarged schematic view of the tip of the capillary needle and the conical jet;
FIG. 3 is a control system block diagram;
FIG. 4 is a start-up process of the monodisperse ultra-fine particle generating apparatus;
wherein: A. the device comprises a single capillary spray needle electrospray module, a B current measurement module, a C image acquisition module, a D high-voltage module, an E logic operation module, an F capillary spray needle tip, a G liquid drop shape schematic diagram, 1 micro sample injector, 2 spray cavity, 3 capillary spray needle, 4 air inlet, 5 carbon dioxide inlet, 6 high-voltage electrode, 7 soft X-ray neutralizer, 8 metal protective shell, 9 conversion resistor, 10 filter capacitor, 11 voltage follower, 12 analog-digital signal converter, 13 CCD camera-microscope lens (X300), 14 programmable array logic (FPGA), 15 digital-analog signal converter, 16 high-voltage source, 17 and single chip microcomputer (STM32F103RCT 6).
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention.
As shown in fig. 1, the monodisperse ultrafine particle stable generation apparatus based on dual closed-loop control according to the present embodiment includes a single capillary spray nozzle electrospray module a, a current measurement module B, an image acquisition module C, a high voltage module D, and a logic operation module E;
the single-capillary spray needle electrospray module A comprises a microsyringe 1, a spray cavity 2, a capillary spray needle 3, an air inlet 4, a carbon dioxide inlet 5, a high-voltage electrode 6, a soft X-ray neutralizer 7 and a metal protective shell 8; the microsyringe is connected with a capillary spray needle 3 through a 1/32' tube 1; the capillary spray needle 3 penetrates through the spray cavity 2 and ensures air tightness with the spray cavity 2; the air inlet 4 and the carbon dioxide inlet 5 penetrate through the spraying cavity 2 and ensure air tightness with the spraying cavity 2; the high-voltage electrode 6 is arranged opposite to the capillary spray needle 3 and is not in contact with the capillary spray needle 3; the soft X-ray neutralizer 7 is arranged outside the spraying cavity 2; the metal protective shell 8 is arranged opposite to the soft X-ray neutralizer 7;
the current measuring module B comprises a current-voltage conversion circuit (consisting of a conversion resistor 9 and a filter capacitor 10), a voltage follower 11 and an analog-digital signal converter 12; the current-voltage conversion circuit comprises a conversion resistor 9 and a filter capacitor 10, one end of the conversion resistor is connected to the capillary spray needle 3 through a wire after the conversion resistor and the filter capacitor are connected in parallel, and the other end of the conversion resistor is grounded; the voltage follower 11 is composed of an operational amplifier, the input end of the voltage follower 11 is connected to the capillary needle 3 through a lead, and the output end is connected to the input end of the analog-digital signal converter 12 through a lead; the output end of the analog-digital signal converter 12 is connected to the logic operation module E through a wire;
the image acquisition module C comprises a CCD camera-micro lens (x 300)13 and a programmable array logic (FPGA) 14; a CCD camera-micro lens (x 300)13 is arranged outside the spray cavity 2, and the digital signal output of the CCD camera 13 is connected to the FPGA (14) through a lead; the FPGA (14) is connected to the logic operation module E through a serial port line;
the high-voltage module D comprises a digital-analog signal converter 15 and a high-voltage source 16; the input end of the digital-analog signal converter 15 is connected with the logic operation module E through a lead, and the output end is connected with the input end of the high voltage source 16 through a lead; the output end of the high voltage source 16 is connected to the high voltage electrode 6 through a high voltage resistant lead;
the logic operation module is composed of a single chip microcomputer (STM32F103RCT6) 17;
when the high-voltage electrode 6 of the device does not apply voltage, the micro-sampler 1 conveys a solution (containing solute) with certain conductivity into the spraying cavity 2 at a certain speed through the capillary spray needle 3, the solution is blown away by air and carbon dioxide (introduced by 4 and 5) to form small droplets, and the small droplets leave the spraying cavity 2 after passing through a soft X-ray irradiation area (provided by 7) along with the air flow; the voltage on the high-voltage electrode 6 is controlled by the high-voltage module D, and along with the gradual rise of the voltage on the high-voltage electrode 6 to a certain range, the solution leaves the capillary spray needle 3 in a conical jet flow mode to form charged liquid drops with uniform size; the charged droplets enter a soft X-ray irradiation area (provided by 7) along with the air flow, the charge quantity is neutralized, the droplet solution volatilizes in the flight process, and the residual solute forms electrically neutral monodisperse particles;
according to the double closed-loop control-based stable generating device for monodisperse ultrafine particles, the shapes of the top end and the top end liquid drops of a capillary spray needle 3 are shot by a CCD camera-micro lens (x 300)13, and images are transmitted to an FPGA (14) in a digital signal form to judge whether conical jet flow is formed or not; if the jet flow is conical, the FPGA (14) calculates the vertex angle of the conical jet flow and then transmits the vertex angle to the logic operation module E;
the double closed loop control-based monodisperse ultrafine particle stable generation device is characterized in that a capillary spray needle 3 of the device is connected to a current measurement module B through a lead; the current signal is converted into a voltage signal after passing through a current-voltage conversion circuit (composed of 9 and 10); in order to prevent the leakage current from influencing the measurement precision, the voltage signal is converted by the voltage follower 11 and then enters the analog-digital signal converter 12; the analog-digital signal converter 12 transmits the current value converted into the digital signal to the logic operation module E;
in the monodisperse ultrafine particle stable generating device based on the double closed-loop control, a command sent to the high-voltage module D by the logic operation module E is a digital signal; the command is converted into an analog signal by a digital-analog signal converter 15 and then transmitted to a high voltage source 16, and the high voltage source 16 provides high voltage for the high voltage electrode 6;
in the monodisperse ultrafine particle stable generating device based on the double closed-loop control, the spraying cavity 2 in the single capillary spraying needle electrospray module A is made of organic glass; the function of the metal protective case 8 installed opposite to the soft X-ray 7 is to prevent the soft X-ray from leaking;
the profile of the capillary needle tip and the droplet shot by a CCD camera-microlens (x 300)13 is obtained after being processed by an FPGA (14), the schematic diagram is shown in FIG. 2, F is the schematic diagram of the capillary needle tip, G is the schematic diagram of the droplet shape, without loss of generality, and a point P is defined as a point with the maximum value of the abscissa (x-axis coordinate) of the droplet; taking a plurality of points along the P point in the forward direction and the reverse direction of the y axis respectively, and fitting a straight line according to a least square method respectively to obtain l 1 :y＝k 1 x+b 1 And l 2 :y＝k 2 x+b 2 (ii) a Then two straight lines l 1 And l 2 Angle alpha of (a) is-arctank 1 +arctank 2 Wherein k is 1 And k 2 Are respectively a straight line l 1 And l 2 Slope of (b) 1 And b 2 Are respectively a straight line l 1 And l 2 The intercept of (d); the least square method for fitting the straight line specifically operates as follows: let the fitting point set be (x) i ,y i ) Wherein i is 1,2,3, …, n; order to
Figure BDA0003622259700000081
Figure BDA0003622259700000082
Then the fitted line is y-kx + b; let mean square error
Figure BDA0003622259700000083
If the mean square error MSE is larger than a certain preset threshold value, judging that the electric spraying system does not reach a conical jet state through the FPGA (14); if the mean square error MSE is not larger than a certain preset threshold, judging that the electric spraying system works in a conical jet flow state through the FPGA (14), and transmitting alpha into a logic operation module E for the next operation;
the control system used in the logic operation module is shown in fig. 3, and comprises two closed loops, namely a main loop (outer loop) with PID1 and an auxiliary control loop (formed by g(s) in the dashed box of fig. 3); the aim of the control system is to maintain the spray currentConstant; in an electrospray system, after a liquid drop forms a conical jet flow, the vertex angle alpha of the liquid drop and the voltage on a high-voltage electrode have positive correlation alpha-h 1 (V), wherein V is the voltage on the high voltage electrode; similarly, the operating current of the electrospray has a positive correlation with the voltage on the high voltage electrode, I ═ h 2 (V), positive correlation h 1 And h 2 Have been verified in the past literature; therefore, the vertex angle of the conical jet has positive correlation I ═ h with the working current 3 (α); h is to be 3 Performing Laplace transform to convert to complex frequency domain to obtain G 2 (s) mixing h 1 Performing Laplace transform to convert to complex frequency domain to obtain G 1 (s); from the above analysis, the high pressure conversion determined by the outer loop control loop is G 1 (s) converting to a droplet shape objective function, the droplet shape output function being G 2 (s) converting the variable into a working current output function to complete variable connection of inner loop control and outer loop control; the input of an outer loop of the control system is an objective function of the working current of the electrospray system, the output is an actual value of the working current, the outer loop carries out PID1 operation (to avoid current fluctuation caused by voltage change being mistaken as a current output value) at a lower frequency (1Hz), and the PID1 obtains an operation result and transmits the operation result to G(s); the input (target value) of the auxiliary control loop is the output of PID1, the auxiliary control loop performs PID2 calculation at a high frequency (30Hz) to control the cone-shaped droplet shape (characterized by the apex angle α) to converge on the input of the auxiliary control loop, and the I ═ h is used as the basis of the result of the calculation 3 (α) it is known that the operating current is considered to be stable by maintaining the shape of the droplet (the vertex angle α of the conical droplet) stable for a short time;
the automatic starting process of the system is shown in FIG. 4; in the flow chart, except for the first step that manual operation is needed for setting the inlet flow of clean air and carbon dioxide and setting the sample injection flow of the solution to be generated, other operations can be automatically completed by a logic operation module E; after air, carbon dioxide and sample injection flow are set, the working voltage of the electrospray system is linearly increased by the logic operation module E, and whether the electrospray system works in a conical jet mode is judged in real time through images shot by a CCD camera-microscope lens (x 300)13 and the method; once the electrospray is operated in the conical jet mode, the voltage is stopped from increasing and the droplet shape, the operating current are waited for to stabilize, and the target current of the dual closed-loop control system is set according to the voltage, and the closed-loop control is entered to make the electrospray operating current converge to the target value.
Specifically, the embodiment of the invention discloses a method for stably generating monodisperse ultrafine particles based on a double closed-loop control system, which comprises the following steps:
s1, manually setting the air inlet flow of clean air and carbon dioxide, manually setting the sample inlet flow of a solution to be generated, automatically linearly increasing the voltage by the logic operation module, continuously judging whether the electrospray module works in a conical jet flow mode, stopping high-pressure change to stabilize working current and droplet shape if the electrospray module works in the conical jet flow mode, setting target current and entering double closed loop control to maintain the working current stability of the electrospray module;
s2, the original color RGB image obtained by the image acquisition module contains complete liquid drops; the color RGB image is subjected to monochrome gray scale conversion and binarization processing to obtain a black-white image, and is subjected to Sobel edge detection algorithm processing to obtain a capillary spray needle tip-liquid drop profile; the FPGA analyzes the contour shape to judge whether the electrospray module works in a conical jet flow mode, if so, the shape of the liquid drop is quantized through the contour, and the vertex angle of the conical liquid drop is calculated to be transmitted to the logic operation module for next calculation;
s3, the logic operation module includes two input signals: the electrospray working current obtained by the current measuring module and the liquid drop profile obtained by the image acquisition module; the logic operation module comprises an output signal: a voltage regulation instruction is sent to the high-voltage module; the double closed-loop control system realized by the logic operation module changes the output voltage by calculating and analyzing two input signals so as to adjust the working current of the electrospray to the target current and realize the stable operation of the electrospray;
s4, the logic operation module makes a difference between the target current and the measured value of the working current to perform outer loop proportional-integral-differential operation; the operation result is converted into a droplet shape target, and the difference is made with the droplet shape measurement value to perform inner ring PID operation; the operation result is converted into a voltage regulation instruction and then applied to the high-voltage electrode; after double closed-loop control, the current of the electric spraying module converges to a set value, and monodisperse ultrafine particles are generated stably.
In summary, the dual closed-loop control system according to the embodiment of the present invention is to control the working current of the electrospray module to be stable at a certain set value (the current stability is a main sign that the electrospray module stably generates monodisperse ultrafine particles). The control system can collect and process the working current of the electrospray module and the image of the liquid drop at the tip of the capillary spray needle, the current measured value and the image signal are used as feedback quantity of the control system, and the working state of the electrospray module is adjusted through the high-voltage adjusting module after the current measured value and the image signal are calculated by the control system so as to adjust the working current of the electrospray module. In long-time work, the generated current is easily interfered by external factors such as air pressure and temperature, and the device can monitor and maintain the stable work of the electrospray module so as to stably generate monodisperse ultrafine particles.
In yet another aspect, the present invention also discloses a computer readable storage medium storing a computer program which, when executed by a processor, causes the processor to perform the steps of any of the methods described above.
In yet another aspect, the present invention also discloses a computer device comprising a memory and a processor, the memory storing a computer program, the computer program, when executed by the processor, causing the processor to perform the steps of any of the methods as described above.
In a further embodiment provided by the present application, there is also provided a computer program product comprising instructions which, when run on a computer, cause the computer to perform the steps of any of the methods of the above embodiments.
It is understood that the system provided by the embodiment of the present invention corresponds to the method provided by the embodiment of the present invention, and the explanation, the example and the beneficial effects of the related contents can refer to the corresponding parts in the method.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by a computer program, which can be stored in a non-volatile computer-readable storage medium, and can include the processes of the embodiments of the methods described above when the program is executed. Any reference to memory, storage, database, or other medium used in the embodiments provided herein may include non-volatile and/or volatile memory, among others. Non-volatile memory can include read-only memory (ROM), Programmable ROM (PROM), Electrically Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), Rambus Direct RAM (RDRAM), direct bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (7)

1. A stable generating device of monodisperse ultrafine particles based on double closed-loop control comprises an electrospray module and a double closed-loop control system, wherein the double closed-loop control system comprises an electrospray module, a current measurement module, an image acquisition module, a high-voltage module and a logic operation module; the method is characterized in that:
the electrospray module comprises a microsyringe, a spray cavity, a capillary spray needle, an air and carbon dioxide inlet, a high-voltage electrode and a soft X-ray neutralizer; the microsyringe is connected with the capillary spray needle through a 1/32' tube; the air inlet and the carbon dioxide inlet penetrate through the spraying cavity and ensure the air tightness with the spraying cavity; the high-voltage electrode is arranged opposite to the capillary spray needle and is not contacted with the capillary spray needle; the soft X-ray neutralizer is arranged outside the spray cavity;
the current measuring module comprises a current-voltage conversion circuit, a voltage follower and an analog-digital signal converter; the current-voltage conversion circuit comprises a conversion resistor and a filter capacitor, one end of the conversion resistor and the filter capacitor is connected in parallel and then is connected to the capillary spray needle through a wire, and the other end of the conversion capacitor is grounded; the voltage follower is composed of an operational amplifier, the input end of the voltage follower is connected to the capillary spray needle through a lead, and the output end of the voltage follower is connected to the input end of the analog-digital signal converter through a lead; the output end of the analog-digital signal converter is connected to the logic operation module through a lead;
the image acquisition module comprises a CCD camera-micro lens and programmable array logic; the CCD camera-microscope lens is arranged on the outer side of the spray cavity, and the digital signal output end of the CCD camera is connected to the programmable array logic through a lead; the programmable array logic is connected to the logic operation module through a serial port line;
the high-voltage module comprises a digital-analog signal converter and a high-voltage source; the input end of the digital-analog signal converter is connected with the logic operation module through a lead, and the output end of the digital-analog signal converter is connected to the input end of a high voltage source through a lead; the output end of the high voltage source is connected to the high voltage electrode through a high voltage resistant lead.
2. The stable generating device of monodisperse ultra-fine particles based on two closed loop controls of claim 1, characterized by that: the material of the spray cavity in the single-capillary spray needle electrospray module is organic glass.
3. The stable generating device of monodisperse ultra-fine particles based on two closed loop controls of claim 1, characterized by that: the logic operation module comprises a singlechip.
4. The stable generating device of monodisperse ultra-fine particles based on two closed loop controls of claim 1, characterized by that: the electrospray module still includes the metal protective housing, the metal protective housing is installed in soft X ray neutralizer opposite, prevents that soft X ray from revealing.
5. A stable generating method of monodisperse ultra fine particles based on double closed loop control system, which adopts the stable generating device of monodisperse ultra fine particles based on double closed loop control of any one of claims 1-4, characterized by comprising the following steps:
when the high-voltage electrode does not apply voltage, the microsyringe conveys the solution with conductivity into the spraying cavity at a set speed through the capillary spray needle, the solution is blown away by air and carbon dioxide to form small droplets, and the small droplets leave the spraying cavity after passing through the soft X-ray irradiation area along with the air flow; the voltage on the high-voltage electrode is controlled by a high-voltage module, and along with the gradual increase of the voltage on the high-voltage electrode to a set range, the solution leaves the capillary spray needle in a conical jet flow mode to form charged liquid drops with uniform size; the charged liquid drops enter the soft X-ray irradiation area along with the air flow, the charge quantity is neutralized, the liquid drop solution volatilizes in the flight process, and the residual solute forms electric neutral monodisperse particles.
6. The method for stably generating the monodisperse ultrafine particles based on the double closed-loop control system according to claim 5, wherein the method comprises the following steps: the shapes of the top end of the capillary spray needle and the top end liquid drop are shot by a CCD camera-micro lens, and the image is transmitted to the FPGA in a digital signal form to judge whether conical jet flow is formed or not; if the jet flow is the conical jet flow, the FPGA calculates the vertex angle of the conical jet flow and then transmits the vertex angle to the logic operation module.
7. A stable generating method of monodisperse ultra fine particles based on double closed loop control system, which adopts the stable generating device of monodisperse ultra fine particles based on double closed loop control of any one of claims 1-4, characterized by comprising the following steps:
s1, manually setting the inlet flow of clean air and carbon dioxide, manually setting the inlet flow of a solution to be generated, automatically linearly increasing the voltage by a logic operation module, continuously judging whether an electrospray module works in a conical jet mode, stopping high-pressure change to stabilize working current and droplet shape if the electrospray module works in the conical jet mode, setting target current and entering double closed loop control to maintain the working current stability of the electrospray module;
s2, the original color RGB image obtained by the image acquisition module contains complete liquid drops; the color RGB image is subjected to monochrome gray scale conversion and binarization processing to obtain a black-white image, and is subjected to Sobel edge detection algorithm processing to obtain a capillary spray needle tip-liquid drop profile; the profile shape is analyzed by the FPGA to judge whether the electrospray module works in a conical jet flow mode, if so, the shape of the liquid drop is quantified through the profile, and the vertex angle of the conical liquid drop is calculated to be transmitted to the logic operation module for next calculation;
s3, the logic operation module includes two input signals: the electrospray working current obtained by the current measuring module and the liquid drop profile obtained by the image acquisition module; the logic operation module comprises an output signal: a voltage regulation instruction is sent to the high-voltage module; the double closed-loop control system realized by the logic operation module changes the output voltage by calculating and analyzing two input signals so as to adjust the working current of the electrospray to the target current and realize the stable operation of the electrospray;
s4, the logic operation module makes a difference between the target current and the measured value of the working current to perform outer loop proportional-integral-differential operation; the operation result is converted into a droplet shape target, and the difference is made with the droplet shape measurement value to perform inner ring PID operation; the operation result is converted into a voltage regulation instruction and then applied to the high-voltage electrode; after double closed-loop control, the current of the electric spraying module converges to a set value, and monodisperse ultrafine particles are generated stably.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023208099A1 (en) * 2022-04-28 2023-11-02 中国科学院合肥物质科学研究院 Double closed loop control-based monodisperse ultrafine particulate matter stable generation apparatus and method

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5873523A (en) * 1996-02-29 1999-02-23 Yale University Electrospray employing corona-assisted cone-jet mode
US20020190203A1 (en) * 2001-05-24 2002-12-19 Valaskovic Gary A. Method and apparatus for feedback controlled electrospray
EP1297895A4 (en) * 2000-06-29 2003-04-02 Anest Iwata Corp Electrostatic painting device
US20050072915A1 (en) * 2003-10-07 2005-04-07 Biospect Inc. Methods and apparatus for self-optimization of electrospray ionization devices
US20090152371A1 (en) * 2005-12-07 2009-06-18 Queen Mary & Westfield College Electrospray Device And A Method of Electrospraying
CN103586154A (en) * 2013-10-29 2014-02-19 华中科技大学 Electrospray device, method of producing solar cell anti-reflection layer by electrospray, and solar cell
US20140242514A1 (en) * 2013-02-25 2014-08-28 Ryota Inoue Particulate material production method, and particulate material production apparatus
US20160059249A1 (en) * 2014-08-26 2016-03-03 Tsi, Inc. Electrospray with soft x-ray neutralizer
CN109996609A (en) * 2016-08-31 2019-07-09 阿维塔斯有限公司 Adaptive electrospray device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103933901B (en) * 2014-04-23 2015-08-19 清华大学 1 ~ 3nm monodisperse aerosol generation systems
CN115025690B (en) * 2022-04-28 2023-05-30 中国科学院合肥物质科学研究院 Monodisperse ultrafine particle stable generation device and method based on double closed-loop control

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5873523A (en) * 1996-02-29 1999-02-23 Yale University Electrospray employing corona-assisted cone-jet mode
EP1297895A4 (en) * 2000-06-29 2003-04-02 Anest Iwata Corp Electrostatic painting device
US20020190203A1 (en) * 2001-05-24 2002-12-19 Valaskovic Gary A. Method and apparatus for feedback controlled electrospray
US20050072915A1 (en) * 2003-10-07 2005-04-07 Biospect Inc. Methods and apparatus for self-optimization of electrospray ionization devices
US20090152371A1 (en) * 2005-12-07 2009-06-18 Queen Mary & Westfield College Electrospray Device And A Method of Electrospraying
US20140242514A1 (en) * 2013-02-25 2014-08-28 Ryota Inoue Particulate material production method, and particulate material production apparatus
CN103586154A (en) * 2013-10-29 2014-02-19 华中科技大学 Electrospray device, method of producing solar cell anti-reflection layer by electrospray, and solar cell
US20160059249A1 (en) * 2014-08-26 2016-03-03 Tsi, Inc. Electrospray with soft x-ray neutralizer
CN109996609A (en) * 2016-08-31 2019-07-09 阿维塔斯有限公司 Adaptive electrospray device
US20190217315A1 (en) * 2016-08-31 2019-07-18 Avectas Limited Adaptive electrospray device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023208099A1 (en) * 2022-04-28 2023-11-02 中国科学院合肥物质科学研究院 Double closed loop control-based monodisperse ultrafine particulate matter stable generation apparatus and method

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