Online control system for tobacco flow rate during pneumatic conveying and characterization method for tobacco breakage

Abstract

The present invention discloses an online control system for tobacco flow rate during pneumatic conveying and a method for characterizing tobacco breakage. The system includes a tobacco feeder, a solid mass flow detection device, equipment piping, a cigarette making machine collection box, a tobacco flow rate balance control device, an air supply device, a control module, a dust removal device, and a dust removal fan. The system utilizes gas-solid two-phase flow measurement technology to directly convert online detection signals into real-time tobacco flow rate. The control module also provides automatic feedback control, thereby improving tobacco stability during conveying and reducing tobacco breakage. The present invention also enables rapid quantitative analysis and accurate evaluation of tobacco breakage by online monitoring of tobacco mass flow and tobacco dust mass flow during pneumatic conveying, providing basic data and a reference basis for designing process parameters such as air flow rate and piping structure, as well as equipment structure, during pneumatic conveying.

Description

Technical Field

[0001] The invention relates to an online control system for tobacco shred flow rate during pneumatic conveying and a method for characterizing tobacco shredding. Background Art

[0002] Pneumatic conveying is widely used in the production process of cigarette factories. Typically, a pneumatic conveying system with negative pressure dilute phase conveying is used for tobacco distribution. This not only prevents material loss and dust from flying, thus reducing dust levels in the workshop, but also removes debris such as stems and clumps.

[0003] Pneumatic tobacco feed systems typically adjust process parameters based on air flow rate. However, actual tobacco speed varies significantly from air flow rate and is significantly affected by the type of tobacco material. Excessively high tobacco speeds can lead to increased tobacco breakage during transport, resulting in material loss that directly impacts tobacco quality and cigarette production costs. In actual production, air flow rate can be adjusted by measuring the degree of tobacco breakage before and after pneumatic feed, but this is time-consuming, labor-intensive, and difficult to implement.

[0004] Traditional methods for characterizing tobacco shreddedness primarily rely on the whole and broken tobacco ratios before and after air conveying, or the fines content. Alternatively, process testing can be performed to assess tobacco shreddedness by collecting and weighing the fines collected during dust removal. While these methods can accurately measure tobacco shreddedness, they are labor-intensive and inefficient. Summary of the Invention

[0005] In order to overcome the shortcomings of the existing technology, the present invention provides an online control system for the tobacco flow rate during pneumatic conveying and a method for characterizing tobacco crushing, so as to automatically and accurately control the tobacco flow rate during pneumatic conveying. On this basis, a quantitative method is used to accurately characterize the tobacco crushing during pneumatic conveying, thereby providing technical support for optimizing the tobacco pneumatic conveying process parameters.

[0006] To achieve the purpose, the present invention adopts the following technical solutions:

[0007] The present invention provides an online control system for the flow rate of cut tobacco during pneumatic conveying, which comprises: a cut tobacco feeder, a solid mass flow detection device, equipment pipelines, a cut tobacco collection box for a cigarette making machine, a cut tobacco flow rate balance control device, an air supply device, a control module, a dust removal device, and a dust removal fan; wherein the solid mass flow detection device comprises a capacitance measurement type gas-solid two-phase flow mass flowmeter; the equipment pipelines comprise a cut tobacco feed pipeline and a dust removal pipeline;

[0008] The dust removal fan provides negative pressure power for the pneumatic conveying process, so that the wire feeder quantitatively delivers tobacco to the cigarette machine collection box through the wire feeding pipe; a screen is provided at the air outlet of the cigarette machine collection box, so that the finished tobacco delivered to the cigarette machine collection box by air is filtered by the screen, and the larger tobacco is retained in the cigarette machine collection box and delivered to the cigarette rolling machine for cigarette rolling, and the remaining smaller tobacco is delivered to the dust removal pipe through the screen; the capacitance measurement type gas-solid two-phase flow mass flowmeter is provided on the wire feeding pipe, for collecting the capacitance signal in the wire feeding pipe and sending it to the control module;

[0009] The smoke dust passing through the screen is transported to the dust removal device through the dust removal duct for dust reduction; the tobacco flow rate balancing control device and the air supply device are sequentially arranged on the dust removal duct; wherein the tobacco flow rate balancing control device and the air supply device are both provided with butterfly valves and driven by a servo motor;

[0010] The control module calculates the real-time flow velocity v1(t) of the tobacco in the wire feeding pipe based on the received capacitance signal, and compares it with the set value of the tobacco flow velocity. After obtaining the comparison result, the control module sends control instructions to the tobacco flow velocity balance control device and the air supply device respectively, so that the tobacco flow velocity balance control device adjusts the opening of the butterfly valve through the servo motor to adjust the real-time flow velocity of the tobacco in the wire feeding pipe in real time, and the servo motor in the air supply device synchronously drives the opening of the butterfly valve to supply air to the dust removal pipe, so as to realize automatic tracking, adjustment and balancing of the real-time flow velocity of the tobacco.

[0011] The online control system for tobacco flow rate during pneumatic conveying according to the present invention is also characterized in that the control module sends control instructions to the tobacco flow rate balancing control device and the air supply device respectively according to the comparison result in the following process:

[0012] When the comparison result shows that the real-time flow rate of the tobacco in the wire feeding duct is less than the set value of the tobacco flow rate, the control module sends a control instruction for increasing the opening to the tobacco flow rate balancing control device, so that the tobacco flow rate balancing control device increases the opening of its own butterfly valve; at the same time, it sends a control instruction for decreasing the opening to the air supply device, so that the air supply device decreases the opening of its own butterfly valve;

[0013] When the comparison result shows that the real-time flow rate of the tobacco in the wire feeding pipe is greater than the set value of the tobacco flow rate, the control module sends a control instruction to reduce the opening to the tobacco flow rate balance control device, so that the tobacco flow rate balance control device reduces the opening of its own butterfly valve; at the same time, it sends a control instruction to increase the opening to the air supply device, so that the air supply device increases the opening of its own butterfly valve.

[0014] The control module calculates the real-time flow velocity v1(t) of the tobacco according to the received capacitance signal as follows:

[0015] Step 1.1: Let the interaxial distance between the two sensors in the capacitance measurement gas-solid two-phase flow mass flowmeter be L, and use formula (1) to construct the cross-correlation function R xy The relationship between the flow time τ(t) of tobacco in the capacitance measurement gas-solid two-phase flow mass flow meter is used to draw the cross-correlation function R xy A curve graph is shown, wherein the abscissa value corresponding to the peak value of the curve graph is the flow time τ(t) of the tobacco from the upstream sensor to the downstream sensor at time t;

[0016] (1)

[0017] In formula (1), x(t) is the capacitance signal of the upstream sensor in the capacitance measurement type gas-solid two-phase flow mass flowmeter at time t, y(t+τ) is the capacitance signal of the downstream sensor in the capacitance measurement type gas-solid two-phase flow mass flowmeter at time t+τ; T is the signal sampling time;

[0018] Step 1.2: Calculate the flow velocity v1(t) of the tobacco in the wire feeding pipe at time t using formula (2):

[0019] (2).

[0020] The method for characterizing tobacco shreds during pneumatic conveying of the present invention is characterized in that it is applied to the online control system, and the solid mass flow detection device further includes: an electrostatic induction gas-solid two-phase flow mass flowmeter, which is arranged on the dust removal pipeline and is used to monitor the current signal I in the dust removal pipeline and transmit it to the control module;

[0021] The control module calculates the tobacco end mass flow rate M2 according to the current signal I, and calculates the tobacco cut mass flow rate M1 according to the real-time flow velocity v1(t) of the tobacco cut, thereby calculating the characteristic index A of tobacco cut breakage during the pneumatic conveying process.

[0022] The method for characterizing tobacco shreds during pneumatic conveying according to the present invention is also characterized in that the control module (10) calculates the tobacco shred mass flow rate M1 according to the real-time flow velocity v1(t) of the tobacco shreds in the following steps:

[0023] Step 1.1: Measure the empty pipe capacitance C of the capacitance measurement type gas-solid two-phase flow mass flowmeter. z and the full tube capacitance C s , where C z C is the capacitance value when the capacitance measurement type gas-solid two-phase flow mass flowmeter is filled with air. sIt is the capacitance value when the capacitance measurement type gas-solid two-phase flow mass flowmeter is filled entirely with tobacco;

[0024] Step 1.2: Measure the real-time capacitance value C(t) of the gas-solid two-phase flow meter in capacitance measurement mode at time t during tobacco air delivery, and calculate the cross-sectional volume fraction α(t) of tobacco in the wire delivery pipe (3) at time t using formula (3):

[0025] (3)

[0026] Step 1.3: Calculate the suspended density ρ(t) of the tobacco in the wire feeding pipe (3) at time t using formula (4):

[0027] (4)

[0028] In formula (4), ρ0 represents the density of tobacco;

[0029] Step 1.4: Calculate the mass flow rate M1(t) of tobacco at time t using formula (5):

[0030] (5)

[0031] In formula (5), S is the cross-sectional area of ​​the wire feeding pipe.

[0032] The control module constructs the relationship between the current signal I generated by the smoke dust flowing through the electrostatic induction gas-solid two-phase flow mass flowmeter and the smoke dust mass flow rate M2 through formula (6):

[0033] (6)

[0034] In formula (8), λ is the coefficient, a is the exponent, and b is the constant;

[0035] The control module calculates the tobacco shredding index A during pneumatic conveying according to the following steps:

[0036] Step 2.1, based on the curve of the change of the tobacco mass flow rate M1 over time, calculate the tobacco mass m1 delivered from the tobacco feeder to the tobacco collection box of the cigarette making machine by using the integral method;

[0037] Step 2.2, based on the time-varying curve of the smoke dust mass flow rate M2, calculate the smoke dust mass m2 flowing through the dust removal duct using an integral method;

[0038] Step 2.3: Calculate the tobacco shredding index A during pneumatic conveying using formula (7):

[0039] (7)

[0040] In step 2.1, the tobacco mass m1 is calculated using formula (8):

[0041] (8)

[0042] In formula (8), σ is the pneumatic conveying time of tobacco.

[0043] Step 2.2 is to calculate the smoke dust mass m2 using formula (9):

[0044] (9)

[0045] In formula (9), ε is the pneumatic transport time of smoke dust.

[0046] The electronic device of the present invention includes a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the characterization method, and the processor is configured to execute the program stored in the memory.

[0047] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0048] The present invention utilizes gas-solid two-phase flow measurement technology to directly convert online detection signals into real-time flow rates of tobacco shreds, and can automatically feedback control through a control module to improve the stability of tobacco shreds during transportation and reduce tobacco breakage. On this basis, by online monitoring of the mass flow rates of tobacco shreds and tobacco dust during the air conveying process, the tobacco breakage situation is quickly quantitatively analyzed and accurately evaluated, providing basic data and reference basis for the design of process parameters such as air flow rate and pipeline structure and equipment structure in the pneumatic conveying process. In addition, the use of this online metering system provides technical support for the intelligent control of wind-powered wire feeding systems and equipment health status monitoring, helps to improve the stability of tobacco shreds conveying wind speed or accurately predicts possible wear and tear of the conveying pipeline, and provides guarantees for the smooth operation of the equipment. In addition, the method of the present invention has the advantages of easy operation and accurate results. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 Schematic diagram of the structure of the online control system for the flow rate of tobacco in the pneumatic conveying process of the present invention;

[0050] Figure 2 Schematic diagram of the detection and signal acquisition processing process of the capacitance measurement type gas-solid two-phase flow mass flowmeter 2 of the present invention;

[0051] Figure 3 1 is a graph showing the relationship between the mass flow rate of tobacco shreds and time according to the present invention.

[0052] Numbers in the figure: 1 wire feeder; 2 capacitance measurement type gas-solid two-phase flow mass flowmeter; 3 wire feeding pipeline; 4 cigarette making machine wire collection box; 5 screen; 6 electrostatic induction type gas-solid two-phase flow mass flowmeter; 7 tobacco flow rate balance control device; 8 dust removal pipeline; 9 air supply device; 10 control module; 11 dust removal device; 12 dust removal fan. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not limit the scope of protection of the present invention.

[0054] This embodiment provides an online control system for the flow rate of tobacco cut in a pneumatic conveying process, comprising: a tobacco cut feeder 1, a solid mass flow detection device, an equipment pipeline, a tobacco cut collection box 4, a tobacco cut flow rate balance control device 7, an air supply device 9, a control module 10, a dust removal device 11, and a dust removal fan 12; wherein the solid mass flow detection device comprises: a capacitance measurement type gas-solid two-phase flow mass flow meter 2 and an electrostatic induction type gas-solid two-phase flow mass flow meter 6; the equipment pipeline comprises: a wire feeding pipeline 3 and a dust removal pipeline 8; such as Figure 1 shown.

[0055] The dust removal fan 12 provides negative pressure power for the pneumatic conveying process, so that the wire feeder 1 can quantitatively deliver tobacco to the cigarette machine collection box 4 through the wire feeding pipe 3; a screen 5 is provided at the air outlet of the cigarette machine collection box 4, which has a mesh structure and a mesh size of usually 30 meshes, so that the finished tobacco delivered to the cigarette machine collection box 4 by air is filtered by the screen 5. Tobacco with a size larger than 30 meshes is retained in the cigarette machine collection box 4 and transported to the cigarette rolling machine for cigarette rolling. The remaining tobacco with a size smaller than 30 meshes is transported to the dust removal pipe 8 through the screen 5, reducing the removal of empty ends during the rolling process. A capacitance measurement type gas-solid two-phase flow mass flowmeter 2 is provided on the wire feeding pipe 3 to collect the capacitance signal in the wire feeding pipe 3 and send it to the control module 10;

[0056] The smoke dust passing through the screen 5 is transported via the dust removal duct 8 to the dust removal device 11 for dust reduction. The dust removal duct 8 is sequentially provided with an electrostatic induction gas-solid two-phase flow mass flowmeter 6, a tobacco flow rate balance control device 7, and an air supply device 9. Both the tobacco flow rate balance control device 7 and the air supply device 9 are equipped with butterfly valves driven by servo motors. The electrostatic induction gas-solid two-phase flow mass flowmeter 6 is used to monitor the current signal I in the dust removal duct 8 and transmit it to the control module 10.

[0057] The control module 10 calculates the real-time flow velocity v1(t) of the tobacco in the wire feeding pipe 3 based on the received capacitance signal, and compares it with the set value of the tobacco flow velocity. After obtaining the comparison result, the control instruction is sent to the tobacco flow velocity balance control device 7 and the air supply device 9 respectively, so that the tobacco flow velocity balance control device 7 adjusts the opening of the butterfly valve through the servo motor to adjust the real-time flow velocity of the tobacco in the wire feeding pipe 3 in real time, and the servo motor in the air supply device 9 synchronously drives the opening of the butterfly valve to supply air to the dust removal pipe 8, so as to realize automatic tracking, adjustment and balance of the real-time flow velocity of the tobacco.

[0058] In this embodiment, the control module 10 calculates the real-time flow velocity v1(t) of the tobacco according to the received capacitance signal as follows:

[0059] Step 1.1: The interaxial distance between the two sensors in the capacitance measurement type gas-solid two-phase flow mass flowmeter 2 is recorded as L, as follows: Figure 2 As shown. The interaxial distance of the equipment used on site is 10 mm. It is necessary to keep the distance between the electrostatic sensors small enough so that the change of the tobacco flow from the upstream to the downstream sensor is relatively small. It can be approximately considered that the tobacco flow shape remains unchanged within the interaxial distance. Therefore, the cross-correlation function R can be constructed using formula (1) xy The relationship between the flow time τ(t) of the tobacco in the capacitance measurement type gas-solid two-phase flow mass flow meter 2 is plotted to draw the cross-correlation function R xy The peak value of the curve is the time τ(t) that the tobacco flows from the upstream sensor to the downstream sensor at time t.

[0060] (1)

[0061] In formula (1), x(t) is the capacitance signal of the upstream sensor in the capacitance measurement type gas-solid two-phase flow mass flowmeter (2) at time t, y(t+τ) is the capacitance signal of the downstream sensor in the capacitance measurement type gas-solid two-phase flow mass flowmeter (2) at time t+τ; T is the signal sampling time; Figure 2 As shown;

[0062] Step 1.2: Calculate the flow velocity v1(t) of the tobacco in the wire feeding pipe (3) at time t using formula (2):

[0063] (2)

[0064] The flow time τ(t) is a real-time value, which can be collected and determined in real time by the control module 10, so as to calculate the tobacco flow rate v1(t) at different times.

[0065] During the actual pneumatic conveying process, the tobacco flow rate is set to 10 m / s in the control module. Based on the comparison results, the control module 10 sends control instructions to the tobacco flow rate balance control device 7 and the air supply device 9 in the following process:

[0066] When the comparison result shows that the real-time flow velocity of the tobacco in the wire feeding duct 3 is less than 10 m / s, the control module 10 sends a control instruction to increase the opening to the tobacco flow velocity balance control device 7, causing the tobacco flow velocity balance control device 7 to increase the opening of its own butterfly valve; at the same time, it sends a control instruction to decrease the opening to the air supply device 9, causing the air supply device 9 to decrease the opening of its own butterfly valve;

[0067] When the comparison result shows that the real-time flow rate of the tobacco in the wire feeding pipe 3 is greater than 10 m / s, the control module 10 sends a control instruction to reduce the opening to the tobacco flow rate balance control device 7, so that the tobacco flow rate balance control device 7 reduces the opening of its own butterfly valve; at the same time, it sends a control instruction to increase the opening to the air supply device 9, so that the air supply device 9 increases the opening of its own butterfly valve.

[0068] In this embodiment, the characterization method of tobacco shreds during pneumatic conveying is calculated as follows:

[0069] First, the control module 10 calculates the tobacco mass flow rate M1(t) according to the real-time flow rate v1(t) of the tobacco according to the following steps:

[0070] Step 2.1: Measure the empty pipe capacitance C of the capacitance measurement type gas-solid two-phase flow mass flowmeter 2. z and the full tube capacitance C s , where C z is the capacitance value when the capacitance measurement type gas-solid two-phase flow mass flowmeter 2 is completely filled with air, C s is the capacitance value when the capacitance measurement type gas-solid two-phase flow mass flowmeter 2 is fully filled with tobacco; at the cigarette enterprise site, the capacitance measurement type gas-solid two-phase flow flowmeter is calibrated, and its empty pipe capacitance value C z and the full tube capacitance C s They are 327 pF and 412 pF respectively. The calibration values ​​are input into the control module.

[0071] Step 2.2: Measure the real-time capacitance value C(t) of the gas-solid two-phase flow meter 2 in capacitance measurement mode during tobacco air delivery at time t, and calculate the cross-sectional volume fraction α(t) of tobacco in the wire feeding duct 3 at time t using formula (3):

[0072] (3)

[0073] Step 2.3: Calculate the suspended density ρ(t) of the tobacco in the wire feeding pipe 3 at time t using formula (4):

[0074] (4)

[0075] In formula (4), ρ0 represents the density of tobacco, which is 60 kg·m -3 .

[0076] Step 2.4: Calculate the mass flow rate M1(t) of tobacco at time t using formula (5):

[0077] (5)

[0078] In formula (5), S is the cross-sectional area of ​​the wire feeding pipe 3. The interior of the gas-solid two-phase flow meter is circular with a diameter of 125 mm. The cross-sectional area of ​​the pipe is calculated to be 0.01227 m 2 .

[0079] According to the tobacco cross-sectional volume fraction α(t), tobacco flow velocity v1(t) and the pipe cross-sectional area of ​​0.01227 m 2 , the tobacco mass flow rate M1(t) is calculated, and the relationship between the tobacco mass flow rate M1(t) and time during the pneumatic conveying process can be output in the control module, such as Figure 3 As shown in Figure 2, based on the time-varying curve of the tobacco mass flow rate M1(t), the tobacco mass m1 delivered from the tobacco feeder 1 to the tobacco collection box 4 of the cigarette making machine is calculated using the integral method. For a medium-speed cigarette making machine, the tobacco mass flow rate M1 in steady state is approximately 0.24 kg·s -1 The tobacco shreds are transported by the cigarette maker under negative pressure for approximately 20 s each time. By integrating the area, it can be calculated that the mass m1 of the tobacco shreds transported from the tobacco feeder 1 to the tobacco collection box 4 of the cigarette maker is 4.52 kg.

[0080] Next, the control module 10 calculates the smoke mass flow rate M2(t) based on the current signal I, and calculates the smoke mass m2 flowing through the dust removal duct 8 using an integral method based on the smoke mass flow rate versus time curve. The calculation process is as follows:

[0081] The smoke dust mass flow rate M2 is related to the current signal I generated when the smoke dust flows through the electrostatic induction gas-solid two-phase flow mass flowmeter 6, and can be calculated using formula (6):

[0082] (6)

[0083] The electrostatic induction gas-solid two-phase flow mass flowmeter 6 was calibrated. After correction, the current signal I and the dust particle mass flow rate M2 were linearly related, with the λ value being 0.117 g·s -1 mA -1 , a value is 1, b value is 0.26 g·s -1During the dust removal process, the control module collects the current signal of the electrostatic induction gas-solid two-phase flow mass flowmeter 6 online. The current signal I fluctuates around 9 mA, and the dust particle flow rate is around 1.05 g·s -1 The dust removal time is about 20 s. Through area integration, it can be calculated that the mass m2 of dust particles flowing through the dust removal pipeline during the dust removal process is 22.15 g.

[0084] Finally, according to the tobacco mass m1 and the tobacco dust mass m2, the tobacco breakage characterization index A during pneumatic conveying is calculated using formula (7):

[0085] (7)

[0086] The characterization index A, which measures the degree of tobacco shredding during pneumatic conveying, is 0.49%. By comparing the magnitude of the characterization index A at different tobacco flow rates, we can qualitatively describe the effect of different tobacco flow rates on tobacco shredding.

[0087] In this embodiment, an electronic device includes a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the above method, and the processor is configured to execute the program stored in the memory.

[0088] In this embodiment, a computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method are executed.

[0089] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. An online control system for the flow rate of tobacco in a pneumatic conveying process, characterized in that: include: A tobacco feeder (1), a solid mass flow detection device, an equipment pipeline, a tobacco collection box (4), a tobacco flow rate balance control device (7), an air supply device (9), a control module (10), a dust removal device (11), and a dust removal fan (12); wherein the solid mass flow detection device includes a capacitance measurement type gas-solid two-phase flow mass flow meter (2); and the equipment pipeline includes a wire feeding pipeline (3) and a dust removal pipeline (8); The dust removal fan (12) provides negative pressure power for the pneumatic conveying process, so that the wire feeder (1) quantitatively blows the tobacco shreds to the cigarette making machine wire collection box (4) through the wire feeding pipe (3); a screen (5) is provided at the air outlet of the cigarette making machine wire collection box (4), so that the finished tobacco shreds blown into the cigarette making machine wire collection box (4) are filtered by the screen (5), and the larger tobacco shreds are retained in the cigarette making machine wire collection box (4) and conveyed to the cigarette rolling machine for cigarette making, and the remaining smaller tobacco shreds are conveyed to the dust removal pipe (8) through the screen (5); the capacitance measurement type gas-solid two-phase flow mass flowmeter (2) is provided on the wire feeding pipe (3) for collecting the capacitance signal in the wire feeding pipe (3) and sending it to the control module (10); The smoke dust passing through the screen (5) is transported to the dust removal device (11) through the dust removal pipe (8) for dust reduction; the tobacco flow rate balance control device (7) and the air supply device (9) are sequentially arranged on the dust removal pipe (8); wherein the tobacco flow rate balance control device (7) and the air supply device (9) are both provided with butterfly valves and driven by a servo motor; The control module (10) calculates the real-time flow velocity v1(t) of the tobacco in the wire feeding pipe (3) based on the received capacitance signal, and compares it with the set value of the tobacco flow velocity. After obtaining the comparison result, the control module (10) sends control instructions to the tobacco flow velocity balance control device (7) and the air supply device (9) respectively, so that the tobacco flow velocity balance control device (7) adjusts the opening of the butterfly valve by the servo motor to control the real-time flow velocity of the tobacco in the wire feeding pipe (3) in real time, and the servo motor in the air supply device (9) synchronously drives the opening of the butterfly valve to supply air to the dust removal pipe (8), so as to realize automatic tracking, adjustment and balance of the real-time flow velocity of the tobacco; The solid mass flow detection device further comprises: an electrostatic induction gas-solid two-phase flow mass flowmeter (6), which is arranged on the dust removal pipeline (8) and is used to monitor the current signal I in the dust removal pipeline (8) and send it to the control module (10); The control module (10) calculates the tobacco end mass flow rate M2 according to the current signal I, and calculates the tobacco cut mass flow rate M1 according to the real-time flow velocity v1(t) of the tobacco cut, thereby calculating the characteristic index A of tobacco cut breakage during the pneumatic conveying process.

2. The online control system for tobacco flow rate during pneumatic conveying according to claim 1, characterized in that: The control module (10) sends control instructions to the tobacco flow rate balance control device (7) and the air supply device (9) respectively according to the comparison result in the following process: When the comparison result shows that the real-time flow rate of the tobacco in the wire feeding pipe (3) is less than the set value of the tobacco flow rate, the control module (10) sends a control instruction for increasing the opening to the tobacco flow rate balance control device (7), so that the tobacco flow rate balance control device (7) increases the opening of its own butterfly valve; and at the same time, sends a control instruction for decreasing the opening to the air supply device (9), so that the air supply device (9) decreases the opening of its own butterfly valve; When the comparison result shows that the real-time flow rate of the tobacco in the wire feeding pipe (3) is greater than the set value of the tobacco flow rate, the control module (10) sends a control instruction for reducing the opening to the tobacco flow rate balance control device (7), so that the tobacco flow rate balance control device (7) reduces the opening of its own butterfly valve; at the same time, it sends a control instruction for increasing the opening to the air supply device (9), so that the air supply device (9) increases the opening of its own butterfly valve.

3. The online control system for tobacco flow rate during pneumatic conveying according to claim 1, characterized in that: The control module (10) calculates the real-time flow velocity v1(t) of the tobacco according to the received capacitance signal in the following manner: Step 1.1, let the interaxial distance between the two sensors in the capacitance measurement type gas-solid two-phase flow mass flowmeter (2) be L, and use formula (1) to construct the cross-correlation function R xy The relationship between the flow time τ(t) of tobacco in the capacitance measurement type gas-solid two-phase flow mass flow meter (2) is used to draw the cross-correlation function R xy The horizontal axis value corresponding to the peak value of the curve is the flow time of the tobacco from the upstream sensor to the downstream sensor at time t. ; (1) In formula (1), x(t) is the capacitance signal of the upstream sensor in the capacitance measurement gas-solid two-phase flow mass flowmeter (2) at time t, The downstream sensor in the capacitance measurement type gas-solid two-phase flow mass flowmeter (2) is The capacitance signal at the moment; T is the signal sampling time; Step 1.2: Calculate the flow velocity v1(t) of the tobacco in the wire feeding pipe (3) at time t using formula (2): (2)。 4. A method for characterizing tobacco shreds during pneumatic conveying, applied to the online control system for tobacco flow rate during pneumatic conveying according to claim 3, characterized in that: The control module (10) calculates the tobacco cut mass flow rate M1 according to the real-time flow rate v1(t) of the tobacco cut according to the following steps: Step 1.1: Measure the empty pipe capacitance C of the capacitance measurement type gas-solid two-phase flow mass flowmeter (2) z and the full tube capacitance C s , where C z is the capacitance value when the capacitance measurement type gas-solid two-phase flow mass flowmeter (2) is filled entirely with air, C s is the capacitance value when the capacitance measurement type gas-solid two-phase flow mass flowmeter (2) is completely filled with tobacco; Step 1.2: Measure the real-time capacitance value C(t) of the gas-solid two-phase flow meter (2) in capacitance measurement mode during tobacco air delivery at time t, and calculate the cross-sectional volume fraction α(t) of the tobacco in the wire delivery duct (3) at time t using formula (3): (3) Step 1.3: Calculate the suspended density ρ(t) of the tobacco in the wire feeding pipe (3) at time t using formula (4): (4) In formula (4), ρ0 represents the density of tobacco; Step 1.4: Calculate the mass flow rate M1(t) of tobacco at time t using formula (5): (5) In formula (5), S is the cross-sectional area of ​​the wire feeding pipe (3).

5. The method for characterizing tobacco shreds during pneumatic conveying according to claim 4, wherein: The control module (10) constructs the relationship between the current signal I generated when the smoke flows through the electrostatic induction gas-solid two-phase flow mass flowmeter (6) and the smoke mass flow rate M2 through the formula (6): (6) In formula (8), λ is a coefficient, a is an exponent, and b is a constant.

6. The method for characterizing tobacco shreds during pneumatic conveying according to claim 4, wherein: The control module (10) calculates the tobacco shredding index A during the pneumatic conveying process according to the following steps: Step 2.1, based on the curve of the change of the tobacco mass flow rate M1 over time, calculate the tobacco mass m1 delivered from the tobacco feeder (1) to the tobacco collection box (4) of the cigarette making machine by using an integral method; Step 2.2, based on the time-varying curve of the smoke dust mass flow rate M2, calculate the smoke dust mass m2 flowing through the dust removal duct (8) by using an integral method; Step 2.3: Calculate the tobacco shredding index A during pneumatic conveying using formula (7): (7)。 7. The method for characterizing tobacco shreds during pneumatic conveying according to claim 6, wherein: In step 2.1, the tobacco mass m1 is calculated using formula (8): (8) In formula (8), σ is the pneumatic conveying time of tobacco.

8. The method for characterizing tobacco shreds during pneumatic conveying according to claim 6, wherein: Step 2.2 is to calculate the smoke dust mass m2 using formula (9): (9) In formula (9), ε is the pneumatic transport time of smoke dust.

9. An electronic device comprising a memory and a processor, characterized in that: The memory is used to store a program that supports a processor to execute the characterization method according to any one of claims 4 to 8, and the processor is configured to execute the program stored in the memory.

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