Airborne charge regulated nonwoven draft device and control method thereof

Abstract

The application relates to the technical field of non-woven fabric drafting equipment, in particular to air-borne charge regulated non-woven fabric drafting equipment and a control method thereof, which comprises air-borne charge regulated non-woven fabric drafting equipment, the equipment has a channel mechanism, an ion air supply mechanism, a partition high-voltage regulation mechanism, a state detection mechanism and a control mechanism, the channel mechanism is provided with a webbing channel along the fiber flow movement direction, the ion air supply mechanism comprises a gas supply assembly and a high-voltage generation assembly, the partition high-voltage regulation mechanism independently controls the discharge voltage of each first electrode through a first bipolar high-voltage power supply and multiple voltage regulation control pieces, the state detection mechanism comprises a first distribution detection assembly and a second distribution detection assembly, and the control mechanism adjusts the output voltage of the corresponding area voltage regulation control piece and the target gas supply flow rate of the adjustable gas supply unit according to the received data, and the application regulates the charge distribution of the fiber flow and the ion concentration of the airflow, so that the width direction density of the fiber flow is more uniform.

Description

Technical Field

[0001] This application relates to the field of nonwoven fabric drafting equipment technology, specifically to a nonwoven fabric drafting equipment and its control method with air-carried charge regulation. Background Technology

[0002] In the production process of spunbond or meltblown nonwoven fabrics, the polymer melt is drawn at high speed and then enters the diffusion duct to form a web. The uniformity of fiber flow dispersion at this stage directly determines the physical properties of the final product. When the polymer melt is drawn into a web by a high-speed airflow, due to the inconsistent frictional forces, a large amount of charge often accumulates on the fiber surface, and it exhibits an uneven and dynamically changing distribution in the width direction.

[0003] Current technologies for static elimination typically employ a global, full-width, uniform control approach. However, in actual wide-width production, the turbulent disturbances of high-speed airflow, minute deformations of the spinneret, and localized fluctuations in melt temperature result in inconsistent frictional forces across the fiber flow along the width, leading to an irregular, patchy distribution of accumulated static charge on the surface. This lack of targeted static elimination often results in incomplete neutralization in areas of high static concentration, while weaker areas experience reverse charge accumulation. Ultimately, this causes the fibers to locally adhere or excessively repel each other under the influence of the electric field, resulting in poor transverse weight uniformity of the nonwoven fabric. Summary of the Invention

[0004] In order to solve the technical problems in the prior art, this application provides a nonwoven fabric stretching device with air-carried charge regulation.

[0005] The nonwoven fabric drafting device with air-carried charge regulation provided in this application adopts the following technical solution:

[0006] A nonwoven fabric drafting device with air-carried charge control includes:

[0007] The channel mechanism has a web-forming channel along the direction of fiber flow for the drawn fiber flow to pass through;

[0008] An ion air supply mechanism includes an air supply component and a high-pressure generating component. The air supply component includes an adjustable air supply unit and a flow guide that is connected to the adjustable air supply unit and has multiple air guide chambers. The high-pressure generating component includes multiple first electrodes and a second electrode that is disposed opposite to the first electrodes and grounded. The first electrodes and second electrodes, which are arranged in pairs, are respectively disposed in the corresponding air guide chambers.

[0009] The zoned high-voltage control mechanism includes a first bipolar high-voltage power supply and multiple voltage regulating control components. The first bipolar high-voltage power supply is electrically connected in parallel to the input terminals of the multiple voltage regulating control components, and the output terminals of the multiple voltage regulating control components are electrically connected to the corresponding first electrodes to independently control the discharge voltage of each first electrode.

[0010] The status detection mechanism includes a first distribution detection component disposed on the inner wall of the web-forming channel and located upstream of the partitioned high-voltage control mechanism, and a second distribution detection component disposed on the inner wall of the web-forming channel and located downstream of the partitioned high-voltage control mechanism. Both the first and second distribution detection components are used to collect data on the distribution of charge in the fiber flow along its width direction.

[0011] The control mechanism includes a control unit electrically connected to the first distributed detection component, the second distributed detection component, the adjustable gas supply unit, and a plurality of the voltage regulating control components. The control unit is used to set the output polarity of the first bipolar high-voltage power supply according to the charge polarity detected by the first distributed detection component; independently adjust the average output voltage of the voltage regulating control component in the corresponding region according to the charge density data of each region fed back by the second distributed detection component; and calculate the sum of the average output voltages of all the voltage regulating control components, and adjust the target gas supply speed of the adjustable gas supply unit based on the sum of the average values.

[0012] By adopting the above technical solution, the control unit locks the main power supply polarity based on the initial charge polarity information collected by the first distribution detection component, and controls the average output voltage of the corresponding area voltage regulating control component based on the real-time charge density detection value collected by the second distribution detection component, so as to independently adjust the discharge intensity of the first electrode in that area; at the same time, the control unit adjusts the total air supply flow of the adjustable air supply unit based on the sum of the average values ​​of the output voltages of all channels. When the average total voltage increases, the air supply flow is automatically increased, using the enhanced airflow thrust to overcome the space charge repulsion effect between high-concentration ions, and using the increased pneumatic pressure head to overcome the space charge repulsion force, promoting the directional migration of ions to the fiber surface.

[0013] Preferably, the web forming channel includes an infeed section, a drawing section connected to the infeed section, and a diffusion section connected to the drawing section at one end away from the infeed section. The infeed section is wedge-shaped with a gradually decreasing cross-sectional area along the fiber flow direction, the drawing section is flat and narrow, and the diffusion section is wedge-shaped with a gradually increasing cross-sectional area along the fiber flow direction. The diffusion section and the drawing section are formed with an air outlet channel that extends obliquely in the direction of fiber flow.

[0014] By adopting the above technical solution, the configuration of the air outlet channel enables the charged airflow to have a component velocity in the same direction as the fiber flow when entering the diffusion section, thereby reducing the turbulent vortex caused by vertical impact that disrupts the fiber flow.

[0015] Preferably, the guide member is installed between the stretching section and the diffusion section. Each air guide chamber includes an air inlet communicating with the adjustable air supply unit, an air inlet channel communicating with the air inlet, an air outlet communicating with the air inlet channel, and an air guide slope extending obliquely from the inner wall of the air guide chamber until it connects with the edge of the air outlet. The oblique direction of the air guide slope is the same as that of the air outlet channel.

[0016] By adopting the above technical solution, the airflow generates a wall-adhering effect when it flows through the guide slope. The gas flows closely to the inner wall of the guide chamber and is guided to the outlet, reducing the vortex and kinetic energy loss of the airflow in dead corners.

[0017] Preferably, the first electrode is a plurality of electrode needles electrically connected to the first bipolar high-voltage power supply, the second electrode is an electrode plate disposed opposite to the plurality of electrode needles and grounded, the air inlet channel is formed between the electrode needles and the electrode plate, the electrode needles are disposed on the inner wall surface of the air guide chamber on one side having the air guide slope, and the air inlet channel, the air outlet and the air outlet channel are all slit-shaped extending along the width direction of the fiber flow.

[0018] By adopting the above technical solution and using an electrode structure tailored to the plate, the requirements for electrode installation accuracy are reduced. Even when the equipment experiences minor vibrations or thermal expansion and contraction during operation, it can maintain a stable inter-electrode distance and discharge intensity. The slit-shaped air inlet and outlet design extending along the width direction ensures that the generated ion wind is uniformly distributed across the entire width of the fiber flow.

[0019] Preferably, the channel mechanism further includes a width adjustment assembly installed on the inner wall of the diffusion section. The width adjustment assembly includes multiple charge adjustment plates corresponding to the inner wall of the diffusion section, and a second bipolar high-voltage power supply electrically connected to the multiple charge adjustment plates. The multiple charge adjustment plates cover the inner wall of the diffusion section, and the second bipolar high-voltage power supply is electrically connected to the control unit.

[0020] By adopting the above technical solution, non-contact width control is achieved by utilizing the lateral effect of the electric field. By adjusting the potential of the charge adjustment plates on the inner wall of the diffusion section, a controllable lateral electrostatic attraction or repulsion force is generated on the passing charged fiber bundles, compensating for the normal contraction displacement of the edge fibers. At the same time, the control unit controls the potential of each charge adjustment plate, and the width and fiber drop point can be controlled through electrostatic attraction or repulsion.

[0021] Preferably, the voltage regulating control component is a high-voltage pulse modulator, the signal input terminal of the voltage regulating control component is electrically connected to the control unit, the control unit is used to send frequency and duty cycle commands to the voltage regulating control component, and the voltage regulating control component is used to modulate the DC voltage output by the first bipolar high-voltage power supply into a pulse voltage.

[0022] By adopting the above technical solution, the control unit controls the average value of the output energy by adjusting the frequency and duty cycle commands sent by the voltage regulation control component, thereby adjusting the total amount of charge neutralization or loading; on the other hand, by adjusting the frequency to generate a high-frequency oscillating electric field, the periodically changing Coulomb force is applied to the fiber to make the fiber bundle vibrate, thereby breaking up the clumps of adhesion between the fibers.

[0023] A control method for an air-charge-regulated nonwoven fabric drafting device, comprising the following steps:

[0024] S1: The control unit collects the initial charge distribution data of the fiber flow through the first distribution detection component to obtain the initial charge polarity information and initial charge density information. If the fiber flow is positively charged, the control unit controls the first bipolar high-voltage power supply to lock the output of negative polarity DC power. If the fiber flow is negatively charged, the control unit controls the first bipolar high-voltage power supply to lock the output of positive polarity DC power.

[0025] S2: The control unit divides the width direction of the fiber flow into N monitoring areas corresponding to the air guide chambers; the control unit obtains real-time charge distribution data of the fiber flow in the width direction through the second distribution detection component, and extracts the real-time charge density detection value corresponding to each monitoring area;

[0026] S3: The control unit matches the base voltage value corresponding to each monitoring area according to the initial charge density information in step S1, and calculates the charge density deviation value of the real-time charge density detection value of each monitoring area relative to the preset target charge density value.

[0027] S4: The control unit uses the base voltage value and the charge density deviation value of each monitoring area to calculate the target compensation voltage of the voltage regulating control element corresponding to each monitoring area through a preset formula, and drives the corresponding voltage regulating control element to perform voltage regulation action;

[0028] S5: The control unit acquires the average value of the output voltage of all N voltage regulating control components in real time, calculates the total average voltage reflecting the total ionization intensity of the system, and generates a flow control command to synchronously adjust the target gas supply speed of the adjustable gas supply unit.

[0029] S6: Repeat steps S2 to S5 until the deviation between the real-time charge density detection value and the target value of all monitoring areas is continuously less than the preset allowable deviation threshold within a preset time period.

[0030] By adopting the above technical solution, the control unit obtains the charge polarity and density distribution of the fiber flow in the width direction in real time through the distributed detection component, pre-locks the polarity of the main power supply, calculates the deviation of each area relative to the reference value, and independently drives the corresponding voltage regulating control component to output the corresponding average output voltage to neutralize the electrostatic patches. At the same time, since the system uses the sum of the average output voltages of all voltage regulating control components to calculate the total average voltage, it ensures that the adjustable air supply unit can accurately obtain the current true total ionization intensity of the system and provide sufficient air supply flow to blow the generated ions to the surface of the fiber flow, avoiding the problem that ions cannot reach the target area due to incorrect airflow calculation.

[0031] Preferably, the calculation of the charge density deviation value in step S3 specifically includes the following steps:

[0032] S31: Obtain the real-time charge density detection value collected by the second distribution detection component within each monitoring area, and record it as... ,in A numerical value that includes both polarity and magnitude information;

[0033] S32: Retrieve the preset target charge density value, denoted as... And it is pre-stored in the control unit;

[0034] S33: Calculate the charge density deviation value of any monitoring area based on the regional detection value of that monitoring area. If the locked output is negative DC, the calculation formula is: If the locked output is positive DC, the calculation formula is: .

[0035] By adopting the above technical solution, this method is based on the power supply's locked polarity switching calculation formula, so that the sign of the calculated deviation value ΔE has a unified instruction meaning, that is, a positive value indicates insufficient compensation and a negative value indicates excessive compensation, which simplifies the subsequent adjustment and control.

[0036] Preferably, the voltage regulation action in step S4 specifically includes the following steps:

[0037] S41: The control unit extracts the initial charge density information collected by the first distribution detection component in step S1, searches a preset charge-voltage correspondence table, and determines the corresponding feedforward base voltage value. ;

[0038] S42: Utilizing the proportional adjustment coefficient and integral adjustment coefficient and the charge density deviation value calculated in step S33. A bidirectional voltage regulation algorithm is constructed to calculate the target compensation voltage. The calculation formula is:

[0039]

[0040] S43: The control unit controls the corresponding voltage regulating control element to perform voltage regulation, and sets the average value of its output voltage according to the following rules: when the calculated value of the target compensation voltage is negative, the average output value is zero; otherwise, the average output value corresponds to the calculated value.

[0041] By employing the above technical solution, the system calculates a target compensation voltage that can be positive or negative using an algorithm that includes proportional and integral terms, making the adjustment process a continuously changing action. The system then processes the calculation result, setting the physical output to zero when the value is negative. This unidirectional compensation logic ensures that the adjustment direction is consistent with the preset polarity, suppressing the problem of reverse charge accumulation caused by overcompensation. Simultaneously, because the integral term of the PI algorithm can continuously operate, it avoids a control dead zone when the static electricity approaches zero, thus maintaining stable control over low-amplitude residual static electricity.

[0042] Preferably, the flow control command in step S5 specifically includes the following steps:

[0043] S51: The control unit (51) collects the average real-time output voltage of all N voltage regulating controllers (32), and records it as... , ,... ... Where i is the monitoring area number, ;

[0044] S52: Calculate the sum of the average output voltages of all voltage regulators as the total average voltage L reflecting the current total ion generation. The calculation formula is: ;

[0045] S53: Based on the total average voltage L and the preset basic flow rate Calculate the theoretical gas demand for this cycle. ,in, The maximum rated voltage allowed by the equipment. The dimensionless positive flux gain coefficient is used to compensate for the repulsive effect of the space charge accumulation region;

[0046] S54: Preset maximum process flow rate threshold and the theoretical gas demand flow rate and Perform a comparison;

[0047] S55: Set the target gas supply flow rate for communication with the adjustable gas supply unit based on the comparison results. :

[0048] like Then set = ;

[0049] like Then set = .

[0050] By adopting the above technical solution, the control unit adjusts the flow rate of the adjustable air supply unit in real time based on the sum of the average output voltages of all voltage regulating controllers. When the voltage regulating controller outputs a high voltage, the concentration of ionized ions increases, and the repulsive force between like ions is enhanced. At this time, the dimensionless positive flow gain coefficient introduced into the formula to compensate for the repulsive effect of the space charge accumulation region allows the control unit of the adjustable air supply unit to adjust a larger air volume according to a preset algorithm. The enhanced airflow thrust overcomes the repulsive resistance of the charge region and delivers ions to the surface of the fiber flow. When the voltage output is low, the system automatically reduces the air volume, ensuring the static electricity neutralization effect while avoiding excessive airflow from disrupting the fiber web structure of the nonwoven fabric.

[0051] In summary, this application includes at least one of the following beneficial technical effects:

[0052] 1. The control unit pre-locks the main power supply polarity based on the polarity information extracted by the first distribution detection component, and determines the electrostatic non-uniform region of the fiber flow in the width direction based on the real-time detection values ​​of charge density in each region collected by the second distribution detection component. Then, it independently drives the corresponding voltage regulation control component to adjust the average discharge output voltage of the first electrode in that region, realizing the zonal compensation of local electrostatic deviation and making the charge compensation more accurate. At the same time, the system establishes a global flow following control strategy based on the total voltage average value. When the voltage regulation control component outputs a high voltage and generates a space charge accumulation region, it uses automatically increased aerodynamic thrust to overcome the self-repulsion effect of the space charge accumulation region, ensuring that a sufficient number of ions can be transported to the surface of the fiber flow.

[0053] 2. Non-contact width control is achieved by utilizing the lateral effect of electric field force. By adjusting the potential of the charge adjustment plates on the inner wall of the diffusion section, a controllable lateral electrostatic attraction or repulsion force is generated on the passing charged fiber bundles, compensating for the normal contraction displacement of the edge fibers. At the same time, the control unit controls the potential of each charge adjustment plate, and the width and fiber flow point can be controlled through electrostatic attraction or repulsion force.

[0054] 3. The control unit controls the average value of the output energy by adjusting the frequency and duty cycle commands sent by the voltage regulating control component, thereby adjusting the total amount of charge neutralization or loading; on the other hand, it generates a high-frequency oscillating electric field by adjusting the frequency, and uses the periodically changing Coulomb force to act on the fiber, causing the fiber bundle to shake, thereby breaking up the clumps of adhesion between the fibers. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the structure of a nonwoven fabric drafting device with air-carrying charge regulation provided in one embodiment of this application;

[0056] Figure 2 This is a cross-sectional view of the flow guide;

[0057] Figure 3 yes Figure 1 Enlarged view of region A in the middle;

[0058] Explanation of reference numerals in the attached drawings: 1. Channel mechanism; 11. Web forming channel; 111. Infeed section; 112. Drawing section; 113. Diffusion section; 114. Air outlet channel; 12. Width adjustment component; 121. Charge adjustment plate; 122. Second bipolar high-voltage power supply; 2. Ion air delivery mechanism; 21. Air supply component; 211. Adjustable air supply unit; 212. Guide component; 213. Air guide chamber; 2131. Air inlet; 2132. Air inlet channel; 2133. Air outlet; 2134. Air guide slope; 22. High-voltage generating component; 221. First electrode; 222. Second electrode; 3. Zoned high-voltage control mechanism; 31. First bipolar high-voltage power supply; 32. Voltage regulation control component; 4. Status detection mechanism; 41. First distribution detection component; 42. Second distribution detection component; 5. Control mechanism; 51. Control unit. Detailed Implementation

[0059] The following is in conjunction with the appendix Figures 1-3 This application will be described in further detail.

[0060] Example 1

[0061] This application discloses an air-charge controlled nonwoven fabric drafting device. (Refer to...) Figure 1-2 , Figure 1This is a schematic diagram of the structure of a nonwoven fabric drafting device with air-carried charge regulation according to an embodiment of this application. The nonwoven fabric drafting device with air-carried charge regulation includes a channel mechanism 1, an ion air supply mechanism 2, a zoned high-pressure regulation mechanism 3, a state detection mechanism 4, and a control mechanism 5. The channel mechanism 1 is used to provide a running channel for the drafted fiber flow. The ion air supply mechanism 2 generates an airflow carrying charge. The zoned high-pressure regulation mechanism 3 independently controls the electrode discharge voltage. The state detection mechanism 4 collects the charge distribution data of the fiber flow. The control mechanism 5 adjusts the output voltage of the pressure regulating control component 32 and the air supply flow of the adjustable air supply unit 211 according to the collected data.

[0062] The channel mechanism 1 has a web-forming channel 11 along the fiber flow direction. The web-forming channel 11 includes an infeed section 111, a drawing section 112, and a diffusion section 113. The infeed section 111 is wedge-shaped with a gradually decreasing cross-sectional area along the fiber flow direction. This shape guides the fiber flow to converge towards the center and smoothly enter the drawing section 112. The drawing section 112 is a flat slit-like shape, which can effectively draw the fiber flow. The diffusion section 113 is wedge-shaped with a gradually increasing cross-sectional area along the fiber flow direction, which facilitates the diffusion and web formation of the fiber flow in the diffusion section 113. The diffusion section 113 and the drawing section 112 are formed with an air outlet channel 114 that extends obliquely in the direction of fiber flow movement. The air outlet channel 114 ensures that the charged airflow has the same velocity component as the fiber flow direction when entering the diffusion section 113, reducing turbulent vortices generated by vertical impact and preventing airflow from disturbing the fiber flow trajectory.

[0063] It should be noted that, in order to achieve high-speed drawing of the fiber flow, the feed section 111 of the channel mechanism 1 is also connected to an external main drawing air source. The main drawing air source is used to continuously introduce high-pressure, high-speed main drawing airflow into the feed section 111. When the main drawing airflow carries the fiber flow through the slit-shaped drawing section 112, the main drawing force is applied to the fiber flow by utilizing the airflow acceleration effect. In this embodiment, the ion air supply mechanism 2, as an auxiliary air supply device, generates a charged airflow with a flow rate and velocity independent of the main drawing airflow, and as a "secondary airflow," it merges into the diffuser section 113 through the outlet channel 114. This arrangement ensures the stability of the flow field of the main drawing airflow.

[0064] Please refer to the following: Figure 3 , Figure 3 yes Figure 1The enlarged view of area A shows that the ion air supply mechanism 2 includes a gas supply component 21 and a high-pressure generating component 22. The gas supply component 21 includes an adjustable gas supply unit 211 and a flow guide 212. Specifically, the adjustable gas supply unit 211 can be a centrifugal fan with a frequency converter or a pump connected in series with an electric proportional regulating valve; it can adjust the motor speed or valve opening according to the electrical signal output by the control unit 51, thereby regulating the total output airflow and providing a gas source for the entire system. The flow guide 212 is installed between the stretching section 112 and the diffusion section 113, communicates with the adjustable gas supply unit 211, and has multiple air guide chambers 213. Each air guide chamber 213 includes an inlet 2131, an inlet channel 2132, an outlet 2133, and a guide slope 2134. The inlet 2131 communicates with the adjustable gas supply unit 211, and gas enters the air guide chamber 213 from the inlet 2131. The air intake channel 2132 is connected to the air intake port 2131, providing a channel for gas flow. The air outlet 2133 is connected to the air intake channel 2132, and the gas is finally discharged from the air outlet 2133. The guide slope 2134 extends obliquely from the inner wall of the guide chamber 213 until it connects with the edge of the air outlet 2133, and the oblique direction is the same as that of the air outlet channel 114. This causes the airflow to generate a wall-adhering effect when it flows through the guide slope 2134. The gas flows closely to the inner wall of the guide chamber 213 and is guided to the air outlet 2133, preventing the airflow from generating vortices in dead corners and causing kinetic energy loss.

[0065] The high-voltage generating assembly 22 includes multiple first electrodes 221 and second electrodes 222. The first electrodes 221 are multiple electrode needles electrically connected to the first bipolar high-voltage power supply 31, and the second electrodes 222 are electrode plates that are grounded and arranged opposite to the multiple electrode needles. An air inlet channel 2132 is formed between the electrode needles and the electrode plate, and the electrode needles are disposed on the inner wall of the air guide chamber 213 on one side with the air guide slope 2134. The relative arrangement of the electrode needles and the electrode plate reduces the requirements for electrode installation accuracy and can maintain a stable inter-electrode distance and discharge intensity when the equipment experiences minor vibrations or displacement due to thermal expansion and contraction during operation. The air inlet channel 2132, the air outlet 2133, and the air outlet channel 114 are all slit-shaped structures extending along the width of the fiber flow, ensuring that the generated ion wind is uniformly distributed across the entire width of the fiber flow.

[0066] The zoned high-voltage control mechanism 3 includes a first bipolar high-voltage power supply 31 and multiple voltage regulation control components 32. The first bipolar high-voltage power supply 31, in conjunction with a polarity switching module, specifically includes a bipolar high-voltage DC power supply and a high-voltage relay. The bipolar high-voltage DC power supply provides a continuously adjustable DC voltage from 0 to ±30kV. The high-voltage relay switches and locks the required power supply polarity according to the initial command from the control unit 51, thereby controlling the airflow blown out in the current production batch to carry a single target polarity ion. The voltage regulation control component 32 is a high-voltage pulse modulator; its input is connected in parallel to the output of the first bipolar high-voltage power supply 31, and its output is electrically connected to the first electrode 221. The control unit 51 sends frequency and duty cycle commands to the voltage regulation control component 32, which modulates the DC high voltage output from the first bipolar high-voltage power supply 31 into a pulse voltage. The control unit 51 controls the average value of the output energy by adjusting the frequency and duty cycle commands, thereby regulating the total amount of charge neutralization in the local area. Simultaneously, it generates a high-frequency oscillating electric field by adjusting the frequency, using periodically changing Coulomb forces to act on the fibers, causing the fiber bundle to vibrate, breaking up the adhering clumps between fibers, and promoting their dispersion. The output terminals of multiple voltage regulating controllers 32 are electrically connected to their respective first electrodes 221, so as to independently control the average discharge voltage of each first electrode 221 under the premise of a unified power supply polarity. By adjusting the output state of the voltage regulating controllers 32, zonal compensation for local electrostatic deviations can be achieved.

[0067] The state detection mechanism 4 is used to monitor the charge throughout the entire process. It includes a first distribution detection component 41 installed on the inner wall of the web-forming channel 11 and located upstream of the zoned high-voltage control mechanism 3, and a second distribution detection component 42 installed on the inner wall of the web-forming channel 11 and located downstream of the zoned high-voltage control mechanism 3. The first distribution detection component 41 collects the initial charge distribution data of the fiber flow before entering the control area and extracts its polarity, providing a basis for polarity preset feedforward control of the system. The second distribution detection component 42 collects the real-time charge density detection value (i.e., residual charge or charged state) of the fiber flow after control, providing a basis for zoned voltage regulation feedback control of the system. Specifically, both the first distribution detection component 41 and the second distribution detection component 42 include a mounting bracket spanning the width of the fiber flow and multiple non-contact electrostatic field sensors, such as vibrating capacitive electrostatic meters or field-milling sensors, arrayed along the width direction. The sensor probes face the wire mesh surface, and the number of sensors corresponds one-to-one with or is multiple of the number of air-guiding chambers 213 in the ion air supply mechanism 2 to achieve point-to-point closed-loop monitoring. The collected data will be transmitted to control unit 5.

[0068] The control mechanism 5 includes a control unit 51, which is electrically connected to the first distribution detection component 41, the second distribution detection component 42, the adjustable air supply unit 211, and multiple pressure regulating controllers 32. The control unit 51 comprehensively processes the initial polarity information collected by the first distribution detection component 41 and the real-time charge density detection values ​​of each region fed back by the second distribution detection component 42, pre-locks the power supply polarity, and independently adjusts the average output voltage of the corresponding region's pressure regulating controller 32. Simultaneously, based on the sum of the average output voltages of all pressure regulating controllers 32, the control unit 51 synchronously adjusts the target air supply speed of the adjustable air supply unit 211. When the pressure regulating controller 32 outputs a high voltage, generating a high-concentration space charge accumulation area, the control unit 51 drives the adjustable air supply unit 211 to increase the flow rate. This increased airflow overcomes the repulsive force of the space charge, improving the efficiency of ion transport to the fiber surface.

[0069] The channel mechanism 1 also includes a width adjustment assembly 12 installed on the inner wall of the diffuser section 113. The width adjustment assembly 12 includes multiple charge adjustment plates 121 corresponding to the inner wall of the diffuser section 113, and a second bipolar high-voltage power supply 122 electrically connected to the multiple charge adjustment plates 121. The charge adjustment plates 121 are specifically made of conductive metal plates with polished surfaces, such as stainless steel plates or aluminum alloy plates, to prevent fibers from adhering to the walls. The charge adjustment plates 121 are embedded in the inner side of the expansion walls on both sides of the diffuser section 113, and a polymer insulating pad, such as a polytetrafluoroethylene plate, is provided between the charge adjustment plates 121 and the housing of the diffuser section 113 to prevent high voltage leakage to the equipment frame. The multiple charge adjustment plates 121 cover the inner wall of the diffuser section 113, and the second bipolar high-voltage power supply 122 is electrically connected to the control unit 51. By adjusting the potential of the charge adjustment plate 121 on the inner wall of the diffusion section 113, the transverse action of the electric field force generates a controllable transverse electrostatic attraction or repulsion force on the passing charged fiber bundle, overcoming the web edge contraction phenomenon during the airflow diffusion process. At the same time, the control unit 51 controls the width and fiber drop point by controlling the potential of each charge adjustment plate 121 and changing the magnitude of the electrostatic attraction or repulsion force.

[0070] It should be noted that the width adjustment component 12 constitutes a subsystem independent of the main charge neutralization system. The second bipolar high-voltage power supply 122 is a completely independent device from the first bipolar high-voltage power supply 31. Its output polarity setting and switching are not based on the initial charge polarity of the fiber flow, but are independently determined by the control unit 51 according to the specific requirements of width adjustment. The control logic of the control unit 51 controlling the second bipolar high-voltage power supply 122 is as follows: The control unit 51 receives real-time fiber flow width data from external devices, such as a vision system or a laser width measuring instrument (not shown in the figure), or calculates the deviation between the current width and the target width based on the operator's preset target width value. Based on this deviation, the control unit 51 determines the voltage polarity and amplitude to be applied to the charge adjustment plate 121, thereby achieving precise control of the web edge fibers and ensuring the stability of the final product width.

[0071] The working principle of this embodiment is as follows: When the first bipolar high-voltage power supply 31 applies high voltage to the electrode needle, a strong corona discharge field is generated at the tip of the electrode needle, which ionizes the air molecules flowing through the air intake channel 2132 into positive or negative ions. At this time, the airflow provided by the adjustable air supply unit 211 serves as a carrier, and the high-concentration ion wind is directionally transported to the surface of the fiber flow in the web-forming channel 11 by using aerodynamic thrust to overcome the self-repulsion effect of the charge region.

[0072] The voltage regulator 32 modulates the DC high voltage into a pulsed waveform. When the voltage is at its peak, a strong corona discharge occurs, and the airflow carries a high density of charge; when the voltage is at its trough or zero, the corona discharge weakens, and the airflow carries very little charge. This periodically changing electric field causes the Coulomb force acting on the fiber to fluctuate at high frequency, which in turn causes the fiber bundle to oscillate at high frequency. This oscillation helps overcome the mechanical adhesion and electrostatic attraction between fibers, promoting the dispersion of fiber filaments. At the same time, because the charge is applied in a pulsating manner, it avoids the overcharging phenomenon caused by the continuous accumulation of charge on the fiber surface. For bicomponent fibers, the pulsating electric field acts on the outer polymer dielectric material, and the repulsive force of like charges between fibers is used to achieve filament separation, avoiding the risk of dielectric breakdown of the fiber material caused by continuous high voltage.

[0073] The working principle of the width adjustment component 12 does not depend on airflow, but rather on establishing a static electric field. By adjusting the potential of the charge adjustment plates 121 on both sides of the diffuser section 113, a transverse electric field is established in the edge region of the mesh. When it is necessary to overcome the shrinkage of the mesh edge, the charge adjustment plates 121 apply a voltage of the same polarity as the fiber, generating a transverse electrostatic repulsive force that pushes the edge fibers outward; when it is necessary to control the scattering, a voltage of opposite polarity is applied to generate an attractive force. This non-contact mechanical action directly corrects the trajectory of the fiber's landing point.

[0074] The state detection mechanism 4 monitors the charge distribution in real time, and the control mechanism 5 dynamically adjusts the voltage amplitude / duty cycle based on the detection data, and simultaneously adjusts the airflow rate. When the system outputs a high voltage to generate a high concentration of ions, the ions tend to remain at the nozzle due to the sharp increase in the Coulomb repulsion force of the space charge. At this time, the system calculates the average total voltage and simultaneously increases the airflow rate to overcome the repulsive resistance, ensuring the effective ion transport efficiency and achieving a match between the electric field ionization intensity and the gas kinetic energy.

[0075] Example 2

[0076] The air-loaded charge-controlled nonwoven fabric drafting equipment control method provided in this application embodiment is mainly applied in the following scenario: under stable production conditions, the electrostatic charge carried by the fiber flow in the width direction has a uniform polarity, and is only non-uniform in density. The control method includes the following steps:

[0077] S1: The control unit 51 collects initial charge distribution data before the fiber flow enters the control area through the first distribution detection component 41 to extract initial charge polarity information and initial charge density information. If the fiber flow is detected to be positively charged overall, the control unit 51 sends a command to the first bipolar high-voltage power supply 31 to control it to lock the output of negative polarity DC power; if the fiber flow is detected to be negatively charged overall, the output of positive polarity DC power is locked. This step sets the neutral polarity of the current continuous production batch.

[0078] S2: The control unit 51 divides the width direction of the fiber flow into N monitoring areas corresponding to the air guide chamber 213; the control unit 51 obtains the real-time charge distribution data of the fiber flow in the width direction through the second distribution detection component 42, and extracts the real-time charge density detection value corresponding to each monitoring area.

[0079] S3: The control unit 51 matches the base voltage value corresponding to each monitoring area based on the initial charge density information in step S1, and calculates the charge density deviation value between the real-time detected charge density value of each monitoring area and the preset target charge density value. The specific steps are as follows:

[0080] S31: Obtain the real-time charge density detection value collected by the second distributed detection component 42 in each monitoring area, denoted as... ,in The value contains both polarity and magnitude information. If the fiber flow surface is positively charged, If the fiber surface is positive, it is negatively charged. It is a negative value.

[0081] S32: Retrieve the preset target charge density value, denoted as... And it is pre-stored in the control unit 51.

[0082] S33: Calculate the charge density deviation value of any monitoring area based on the regional detection value of that monitoring area. If the locked output is negative DC, the calculation formula is: If the locked output is positive DC, the calculation formula is: This logic ensures that the sign of the deviation value ΔE accurately reflects the compensation status: a positive value indicates insufficient compensation, and a negative value indicates excessive compensation.

[0083] S4: The control unit 51 calculates the target compensation voltage corresponding to the voltage regulation control unit 32 using the charge density deviation value, and drives the voltage regulation control unit 32 to perform a voltage regulation action adapted to the target compensation voltage. The specific steps are as follows:

[0084] S41: The control unit 51 calculates the transmission delay based on the filament conveying speed and transmission distance to achieve position correspondence, extracts the initial charge density information corresponding to the current voltage regulation area collected by the first distribution detection component 41 in step S1, searches the preset charge-voltage correspondence table, and determines the feedforward base voltage. This table stores the theoretically required base voltage values ​​for different initial charge levels. The preset charge-voltage correspondence table can be obtained through prior experimental calibration. Specifically, with feedback control disabled, the applied base voltage can be gradually adjusted for different initial charge density values. The residual charge density after neutralization is monitored using the second distribution detection component 42, and the base voltage value that makes the residual charge density closest to the target value (e.g., close to zero) is recorded. This establishes a series of initial charge density and base voltage correspondence data, which is then stored in the control unit 51.

[0085] S42: Utilizing the proportional adjustment coefficient and integral adjustment coefficient and the charge density deviation value calculated in step S33 Calculate the target compensation voltage The calculation formula is: The target compensation voltage is calculated using an algorithm that includes proportional and integral terms, making the adjustment process a continuously changing action.

[0086] S43: The control unit 51 controls the corresponding voltage regulating control unit 32 to perform voltage regulation, and sets the average value of its output voltage according to the following rules: when the calculated value of the target compensation voltage is negative, the average output value is zero; otherwise, the average output value corresponds to the calculated value.

[0087] Since the output polarity of the first bipolar high-voltage power supply 31 has been locked to a single polarity opposite to the polarity of the fiber charge in step S1, all voltage regulating controllers 32 can only output voltages of this locked polarity in the current production batch. When the calculated value of the target compensation voltage is negative, its physical meaning is that a voltage in the opposite direction to the currently locked polarity needs to be applied for reverse compensation, which cannot be achieved when the current polarity is fixed. Therefore, the average output voltage is set to zero.

[0088] S5: The control unit 51 acquires the average value of the output voltage of all voltage regulating controllers 32 in real time, calculates the total average voltage reflecting the total ionization intensity of the system, and uses the total average voltage to generate a flow control command to synchronously adjust the target gas supply speed of the adjustable gas supply unit 211. The specific steps are as follows:

[0089] S51: Control unit 51 collects the average real-time output voltage of all N voltage regulating controllers 32, denoted as... , ,... ... Where i is the monitoring area number, .

[0090] S52: Calculate the sum of the average output voltages of all voltage regulating control units 32, which will be used as the total average voltage L reflecting the current total amount of ion generation. The calculation formula is as follows: ;

[0091] S53: Based on the average total voltage L and the preset base flow rate Calculate the theoretical gas demand for this cycle. The calculation formula is: in, The maximum rated voltage allowed by the equipment. This is a dimensionless positive flow gain coefficient used to compensate for the repulsive effect in the space charge accumulation region. When the voltage regulator 32 outputs a high voltage, leading to an increase in ion concentration and enhanced repulsive force between like ions, the positive coefficient λ is used to enable the adjustable air supply unit 211 to output a larger air volume, enhancing the airflow thrust to overcome the repulsive resistance of the charge region. Conversely, when the voltage is low, the system automatically reduces the airflow, ensuring effective static electricity elimination while preventing excessive airflow from disrupting the nonwoven fabric's fiber web structure. The basic flow rate... λ is the minimum airflow calibrated experimentally to deliver trace amounts of ions to the fiber flow at zero voltage; λ is an empirically adjustable parameter (e.g., 0.5-5.0) designed to effectively deliver ions at high voltage without disturbing the fiber web.

[0092] S54: Preset maximum process flow rate threshold and the theoretical gas demand flow rate and Compare

[0093] S55: Based on the comparison results, set the target gas supply flow rate for communication with the adjustable gas supply unit 211. :like Then set = ;like Then set = This is to avoid excessive airflow that could affect the fiber flow distribution.

[0094] S6: Repeat steps S2 to S5 until the deviation between the real-time charge density detection value and the target value of all monitoring areas is continuously less than the preset allowable deviation threshold within a preset time period.

[0095] The working principle of this embodiment is as follows: This method establishes a numerical deviation between the real-time detection of the charge density on the fiber flow surface and the target value. The system can accurately detect the polarity and strength of static electricity. Through the aforementioned closed-loop control mechanism, the system converts the collected charge distribution data into digital signals and dynamically adjusts the average output voltage of the corresponding region using a formula. The system calculates and performs unidirectional compensation based on the magnitude of the deviation, dynamically reducing the charge density deviation of each region. By dividing the bandwidth into N independent regions, the control unit 51 can individually adjust the output energy of the corresponding voltage regulator 32 for static electricity anomalies in a specific region without affecting other normal regions.

[0096] Furthermore, during high-voltage ionization, the space charge accumulation region generated by the electrodes exhibits the characteristic of like charges repelling each other. If the airflow velocity is insufficient, the charge region will stagnate near the electrodes. Step S5 establishes the physical coupling relationship between the global electric field strength and the total airflow rate by calculating the average total voltage L. When the system outputs a high voltage to generate a large number of ions, due to the positive coefficient... The system automatically increases the air supply flow rate. The increased airflow provides stronger momentum, which can quickly push the charge region accumulated near the electrodes to the fiber flow surface, overcoming the self-repulsion effect of high-concentration ion clouds.

[0097] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Any other corresponding changes and modifications made based on the technical concept of this application should be included within the scope of protection of this application.

Claims

1. A nonwoven fabric drafting device with air-carried charge regulation, characterized in that, include: Channel mechanism (1), wherein the channel mechanism (1) has a web forming channel (11) for the drawn fiber flow to pass through along the direction of fiber flow movement; The ion air supply mechanism (2) includes an air supply component (21) and a high-pressure generating component (22). The air supply component (21) includes an adjustable air supply unit (211) and a flow guide (212) connected to the adjustable air supply unit (211) and having multiple air guide chambers (213). The high-pressure generating component (22) includes multiple first electrodes (221) and second electrodes (222) disposed opposite to the first electrodes (221) and grounded. The first electrodes (221) and second electrodes (222) disposed in pairs are respectively disposed in the corresponding air guide chambers (213). The partitioned high voltage control mechanism (3) includes a first bipolar high voltage power supply (31) and a plurality of voltage regulating control components (32). The first bipolar high voltage power supply (31) is electrically connected in parallel with the input terminals of the plurality of voltage regulating control components (32), and the output terminals of the plurality of voltage regulating control components (32) are electrically connected to the corresponding first electrode (221) to independently control the discharge voltage of each first electrode (221). The status detection mechanism (4) includes a first distribution detection component (41) disposed on the inner wall of the web forming channel (11) and located upstream of the partitioned high-voltage control mechanism (3), and a second distribution detection component (42) disposed on the inner wall of the web forming channel (11) and located downstream of the partitioned high-voltage control mechanism (3). Both the first distribution detection component (41) and the second distribution detection component (42) are used to collect data on the distribution of charge in the fiber flow along the width direction. The control mechanism (5) includes a control unit (51) electrically connected to the first distribution detection component (41), the second distribution detection component (42), the adjustable gas supply unit (211), and a plurality of the pressure regulating control components (32). The control unit (51) is used to set the output polarity of the first bipolar high voltage power supply (31) according to the charge polarity detected by the first distribution detection component (41); independently adjust the average output voltage of the corresponding region of the pressure regulating control component (32) according to the charge density data of each region fed back by the second distribution detection component (42); and calculate the sum of the average output voltages of all the pressure regulating control components (32), and adjust the target gas supply speed of the adjustable gas supply unit (211) based on the sum of the average values.

2. The nonwoven fabric drafting device with air-carried charge regulation according to claim 1, characterized in that, The web forming channel (11) includes an infeed section (111), a drawing section (112) connected to the infeed section (111), and a diffuser section (113) connected to the end of the drawing section (112) away from the infeed section (111). The infeed section (111) is wedge-shaped with a gradually decreasing cross-sectional area along the fiber flow direction. The drawing section (112) is flat and narrow. The diffuser section (113) is wedge-shaped with a gradually increasing cross-sectional area along the fiber flow direction. The diffuser section (113) and the drawing section (112) are formed with an air outlet channel (114) that extends obliquely in the direction of fiber flow.

3. The nonwoven fabric drafting device with air-carried charge regulation according to claim 2, characterized in that, The guide member (212) is installed between the stretching section (112) and the diffusion section (113). Each air guide chamber (213) includes an air inlet (2131) communicating with the adjustable air supply unit (211), an air inlet channel (2132) communicating with the air inlet (2131), an air outlet (2133) communicating with the air inlet channel (2132), and an air guide slope (2134) extending obliquely from the inner wall of the air guide chamber (213) to the edge of the air outlet (2133). The oblique direction of the air guide slope (2134) is the same as that of the air outlet channel (114).

4. The nonwoven fabric drafting device with air-carried charge regulation according to claim 3, characterized in that, The first electrode (221) is a plurality of electrode needles electrically connected to the first bipolar high voltage power supply (31). The second electrode (222) is an electrode plate that is disposed opposite to the plurality of electrode needles and grounded. The air inlet channel (2132) is formed between the electrode needles and the electrode plate. The electrode needles are disposed on the inner wall of the air guide chamber (213) on one side with the air guide slope (2134). The air inlet channel (2132), the air outlet (2133), and the air outlet channel (114) are all slits extending along the width direction of the fiber flow.

5. The nonwoven fabric drafting device with air-carried charge regulation according to claim 2, characterized in that, The channel mechanism (1) further includes a width adjustment assembly (12) installed on the inner wall of the diffusion section (113). The width adjustment assembly (12) includes multiple charge adjustment plates (121) corresponding to the inner wall of the diffusion section (113), and a second bipolar high voltage power supply (122) electrically connected to the multiple charge adjustment plates (121). The multiple charge adjustment plates (121) cover the inner wall of the diffusion section (113), and the second bipolar high voltage power supply (122) is electrically connected to the control unit (51).

6. The nonwoven fabric drafting device with air-carried charge regulation according to claim 1, characterized in that, The voltage regulating control unit (32) is a high-voltage pulse modulator. The signal input terminal of the voltage regulating control unit (32) is electrically connected to the control unit (51). The control unit (51) is used to send frequency and duty cycle commands to the voltage regulating control unit (32). The voltage regulating control unit (32) is used to modulate the DC voltage output by the first bipolar high-voltage power supply (31) into a pulse voltage.

7. A control method for an air-charge-controlled nonwoven fabric drafting device, used to control the air-charge-controlled nonwoven fabric drafting device as described in claim 1, characterized in that, The method includes the following steps: S1: The control unit (51) collects the initial charge distribution data of the fiber flow through the first distribution detection component (41) to obtain the initial charge polarity information and initial charge density information; if the fiber flow is positively charged, the first bipolar high voltage power supply (31) is controlled to lock the output of negative polarity DC power; if the fiber flow is negatively charged, the first bipolar high voltage power supply (31) is controlled to lock the output of positive polarity DC power. S2: The control unit (51) divides the width direction of the fiber flow into N monitoring areas corresponding to the air guide chamber (213); the control unit (51) obtains the real-time charge distribution data of the fiber flow in the width direction through the second distribution detection component (42), and extracts the real-time charge density detection value corresponding to each monitoring area; S3: The control unit (51) matches the base voltage value corresponding to each monitoring area according to the initial charge density information in step S1, and calculates the charge density deviation value of the real-time charge density detection value of each monitoring area relative to the preset target charge density value. S4: The control unit (51) uses the base voltage value and the charge density deviation value of each monitoring area to calculate the target compensation voltage of the voltage regulating control unit (32) corresponding to each monitoring area through a preset formula, and drives the corresponding voltage regulating control unit (32) to perform voltage regulation action. S5: The control unit (51) acquires the average value of the output voltage of all N voltage regulating control units (32) in real time, calculates the average value of the total voltage reflecting the total ionization intensity of the system, and generates a flow control command to synchronously adjust the target air supply speed of the adjustable air supply unit (211). S6: Repeat steps S2 to S5 until the deviation between the real-time charge density detection value and the target value of all monitoring areas is continuously less than the preset allowable deviation threshold within a preset time period.

8. The control method for a nonwoven fabric drafting device with air-carried charge regulation according to claim 7, characterized in that, The calculation of the charge density deviation value in step S3 specifically includes the following steps: S31: Obtain the real-time charge density detection value collected by the second distribution detection component (42) within each monitoring area, and record it as... ,in A numerical value that includes both polarity and magnitude information; S32: Retrieve the preset target charge density value, denoted as... And pre-stored in the control unit (51); S33: Calculate the charge density deviation value of any monitoring area based on the regional detection value of that monitoring area. If the locked output is negative DC, the calculation formula is: If the locked output is positive DC, the calculation formula is: .

9. The control method for a nonwoven fabric drafting device with air-carried charge regulation according to claim 8, characterized in that, The voltage regulation action in step S4 specifically includes the following steps: S41: The control unit (51) extracts the initial charge density information collected by the first distribution detection component (41) in step S1, searches the preset charge-voltage correspondence table, and determines the corresponding feedforward base voltage value. ; S42: Utilizing the proportional adjustment coefficient and integral adjustment coefficient and the charge density deviation value calculated in step S33. Calculate the target compensation voltage The calculation formula is: S43: The control unit (51) controls the corresponding voltage regulating control unit (32) to perform voltage regulation and sets the average value of its output voltage according to the following rules: when the calculated value of the target compensation voltage is negative, the average output value is zero; otherwise, the average output value corresponds to the calculated value.

10. The control method for a nonwoven fabric drafting device with air-carried charge regulation according to claim 7, characterized in that, The flow control command in step S5 specifically includes the following steps: S51: The control unit (51) collects the average real-time output voltage of all N voltage regulating controllers (32), and records it as... , ,... ... Where i is the monitoring area number, ; S52: Calculate the sum of the average output voltages of all voltage regulating control units (32) as the total average voltage L reflecting the current total amount of ion generation. The calculation formula is as follows: ; S53: Based on the total average voltage L and the preset basic flow rate Calculate the theoretical gas demand for this cycle. ,in, The maximum rated voltage allowed by the equipment. The dimensionless positive flux gain coefficient is used to compensate for the repulsive effect of the space charge accumulation region; S54: Preset maximum process flow rate threshold and the theoretical gas demand flow rate and Perform a comparison; S55: Set the target gas supply flow rate for communication with the adjustable gas supply unit based on the comparison results. : like Then set = ; like Then set = .

Images