A method and device for improving the accuracy of online cigarette ventilation detection

Abstract

A device for improving the accuracy of online cigarette ventilation detection includes: an air inlet pipe, a detection drum, graphite arc plates disposed on both sides of the detection drum, an air groove on the side of the graphite arc plates corresponding to the cigarette, a cigarette synchronization signal, and a data acquisition and processing unit. The air path of the air groove is connected to the air inlet pipe and pressure sensors at the graphite arc plates at the inlet and outlet ends of the cigarette. The arc length of the air groove on the graphite arc plate is the length of the detection area of ​​the cigarette. After acquiring the cigarette synchronization signal, the data acquisition and processing unit calculates the pulse period of the signal, performs N frequency divisions, and forms N detection trigger pulses. The pressure sensors average the N detection values ​​to obtain accurate pressure values ​​at the inlet and outlet ends of the cigarette, thereby obtaining a more accurate cigarette ventilation value. This invention does not use conventional nozzles; instead, it uses the processing unit to generate detection allowable pulses, allowing the detection data to avoid fluctuations caused by the cigarette entering and exiting the detection area. This replaces the function of conventional nozzles in suppressing fluctuations.

Description

Technical Field

[0001] This invention belongs to the field of cigarette manufacturing technology, and specifically relates to a device and method for improving the accuracy of online cigarette ventilation detection. Background Technology

[0002] Chinese Patent ZL201410015291.1 describes a method for detecting air leakage when cigarettes are conveyed on a drum. It describes a two-way airflow design using cigarettes in two adjacent slots. The first way has air pressure sensors installed at the inlet and outlet ends to detect air pressure P1 and P2 respectively; the second way has an air pressure sensor installed at the outlet end to detect air pressure P3. The technical solution utilizes 64 enhanced pulses from a shaft encoder to perform 64 pressure signal detections and data processing. Obviously, since the detection device is typically an arc-shaped area matching the detection drum, located at the top of the drum, and each cigarette enters and leaves the detection area in turn, there must be a process of air filling and deflating for each cigarette entering and leaving the detection area. This technical solution clearly does not consider the impact of air pressure fluctuations caused by the filling and deflating of airflow and pressure during cigarette entry and exit from the detection area. Practice has shown that these pressure changes and fluctuations can account for up to 50% of the entire detection area length, inevitably resulting in a large amount of invalid data and certainly affecting the accuracy of the calculations. Furthermore, some cigarette-making units do not use shaft encoders to assist in generating machine pulses, so installing an additional shaft encoder is inconvenient and may even affect the operation of other components.

[0003] Figure 1 This is a schematic diagram of 64 detection pulses generated by a shaft encoder; the diagram shows several stages within one cycle of a cigarette entering and exiting the detection area: In the first stage when the cigarette enters the testing area, the end section of the cigarette enters the testing area, the airflow begins to enter the cigarette, the pressure gradually increases, and it oscillates.

[0004] In the second stage after the smoke has fully entered the testing area, the pressure has risen and stabilized.

[0005] The third stage occurs when the cigarette leaves the detection area. The end section of the cigarette leaves the detection area, the initial airflow entering the cigarette decreases, the pressure gradually decreases, and oscillation occurs.

[0006] In the fourth stage, when the smoke has completely left the detection area, the pressure has decreased and stabilized.

[0007] The testing area awaits the arrival of the next cigarette.

[0008] It is evident that using a shaft encoder to generate 64 detection pulses and sampling one cycle consisting of the above four stages did not improve the detection accuracy.

[0009] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0010] The purpose of this invention is to provide a device for improving the accuracy of online cigarette ventilation detection, thereby overcoming the defects in the prior art.

[0011] To achieve the above objectives, the present invention provides a device for improving the accuracy of online cigarette ventilation detection, comprising: an air inlet pipe, a detection drum, graphite arc plates disposed on both sides of the detection drum, an air groove disposed on the side of the graphite arc plates corresponding to the cigarette, a cigarette synchronization signal, and a data acquisition and processing unit. The air path of the air groove is connected to the air inlet pipe and pressure sensors at the graphite arc plates at the inlet and outlet ends of the cigarette. The arc length of the air groove of the graphite arc plate is the length of the detection area of ​​the cigarette. After acquiring the cigarette synchronization signal, the data acquisition and processing unit calculates the pulse period of the signal. After avoiding the period when the air pressure and airflow are unstable when the cigarette enters or leaves the detection area, it performs N frequency divisions to form N detection trigger pulses. The period when the air pressure and airflow are unstable is obtained by the effective detection time length: T1.

[0012] The pressure sensor generates a detection data point for each detection trigger pulse. The average of N detection values ​​is calculated to obtain accurate pressure values ​​at the cigarette's inlet and outlet, thus yielding a more accurate cigarette ventilation value. The stable air pressure and airflow period is obtained through the effective detection time length: T1, where T1 = (β - α) * T. Coefficient α is the delay from the rising edge of the cigarette synchronization pulse to the rising edge of the first permissible detection pulse, with a value ranging from 30% to 65%. Coefficient β is the delay from the rising edge of the cigarette synchronization pulse to the end of the last detection pulse cycle, with a value ranging from 40% to 98%. T is the duration period between two adjacent cigarette synchronization signals.

[0013] Instead of using conventional nozzles, a detection allowance pulse is generated by a computing unit, allowing the detection data to avoid fluctuations caused by the cigarette entering and leaving the detection area. This replaces the fluctuation suppression function of conventional nozzles.

[0014] Preferably, in the above technical solution, the cigarette synchronization signal includes a pulse signal from the cigarette positioning sensor and a pulse signal from the machine clock, and the cigarette synchronization signal corresponds to the speed and position of each cigarette.

[0015] Preferably, in the above technical solution, one cigarette corresponds to only one cigarette synchronization signal pulse.

[0016] Preferably, in the above technical solution, the pressure values ​​corresponding to the pressure sensors set at the graphite arc plate at the inlet end and the graphite arc plate at the outlet end of the cigarette are: Pin is the pressure sensor value at the inlet end of the cigarette, and Pout is the pressure sensor value at the outlet end of the cigarette. The entry or exit of a cigarette into or from the arc-shaped gas groove detection area of ​​the graphite arc plate causes a change in Pin and Pout rates within the range of 9%-4.8%.

[0017] Preferably, in the above technical solution, the data acquisition and processing unit performs the following calculation based on the cigarette synchronization signal when the cigarette machine speed is greater than X cigarettes / minute, where X is a positive integer greater than 100: S1, obtain the duration period T between two adjacent cigarette synchronization signals; S2, set the delay from the initial rising edge of the cigarette synchronization pulse to the rising edge of the first allowable detection pulse, with a coefficient of α 30-65%; S3, set the delay from the rising edge of the cigarette synchronization pulse to the end of the last detection pulse cycle, with a coefficient of β 40~98%; S4, obtain the effective detection time length: T1 = (β-α) * T; S5, set the number of pressure sensor data acquisitions N and pulse duty cycle N1 required within time T1, and obtain the detection trigger pulse with period T2=T1 / N and duty cycle N1%; S6, after a delay of α from the rising edge of the cigarette synchronization pulse, the operation and control unit issues an allow detection pulse, which is a sequence of N allow detection pulses with a period of T1 / N and a duty cycle of N1%. S7, the data acquisition unit collects data from the pressure sensors at the air inlet end and the air outlet end of the two pairs of air inlet slots according to the detection trigger pulse issued by the calculation control unit, and obtains data from N pressure sensors corresponding to each cigarette, namely N data for P1 inlet, P1 outlet, and P2 inlet and P2 outlet respectively. S8, calculate the average value of the above N valid data for each pressure sensor: P = (P1 + ... + PN) / N, which means P1 enters the average, P1 exits the average, and P2 enters the average, P2 exits the average. S9. If the air inlet ends of the two sets of air inlet slots correspond to the ignition end of the cigarette, and the air outlet ends of the two sets of air outlet slots correspond to the filter end of the cigarette, then both sets of detection adopt forward detection airflow, and the airflow flows from the ignition end of the cigarette to the filter end of the cigarette. Consequently, we obtain: P_in average = (P1_in average + P2_in average) / 2 P_average = (P_1 average + P_2 average) / 2 The ventilation degree F of the cigarette rod = (P average of inlet - P average of outlet), Or: The ventilation degree F of the cigarette rod = (P average of inlet - P average of outlet) / P average of inlet; S10, if the inlet end of the group of air inlet slots corresponds to the ignition end of the cigarette rod and the outlet end of the air outlet slots corresponds to the filter tip end of the cigarette rod (detecting the air flow in the forward direction, that is, the detecting air flow flows from the ignition end of the cigarette rod to the filter tip end of the cigarette rod), and the inlet end of the other group of air inlet slots corresponds to the filter tip end of the cigarette rod and the outlet end of the air outlet slots corresponds to the ignition end of the cigarette rod (detecting the air flow in the reverse direction, that is, the air flow flows from the filter tip end of the cigarette rod to the ignition end of the cigarette rod); Furthermore, it is obtained that: The forward ventilation degree F positive of the cigarette rod = (P average of inlet 1 * C1 - P average of outlet 1 * C2), Or F positive = (P average of inlet 1 * C1 - P average of outlet 1 * C2) / P average of inlet 1, The reverse ventilation degree F reverse of the cigarette rod = (P average of inlet 2 * C3 - P average of outlet 2 * C4), Or F reverse = (P average of inlet 2 * C3 - P average of outlet 2 * C4) / P average of inlet 2, C1\C2\C3\C4 are adjustment coefficients, which are adjustment constants required for monitoring parameter calibration; S11, the forward filter tip ventilation degree of the cigarette rod: Fv1 = β1 * F positive, where β1 is a set adjustment coefficient, The reverse filter tip ventilation degree of the cigarette rod: Fv2 = β2 * F reverse, where β2 is a set adjustment coefficient, The filter tip ventilation degree of the cigarette rod: PV = Fv1 * C1 + Fv2 * C2.

[0018] The application of the above operations and methods can achieve the function of replacing the shaft encoder, and the installation is simple and fast. Moreover, there is no need to use software and hardware to judge invalid data, which simplifies the system design and also reduces the cost. The average value calculation method reduces the measurement and calculation errors caused by factors such as air pressure fluctuations, machine operation fluctuations, and cigarette rod jitter.

[0019] Preferably, in the above technical solution, the coefficient α in S2 is 40% - 55%.

[0020] Preferably, in the above technical solution, the coefficient β in S3 is 45% - 85%.

[0021] The device for on-line detecting the ventilation degree of cigarette rods includes: an air inlet pipe, a throttling air inlet nozzle, a detecting drum, graphite arc plates arranged on both sides of the detecting drum, pressure sensors arranged at the graphite arc plate at the air inlet end of the cigarette rod and the graphite arc plate at the air outlet end of the cigarette rod, a cigarette rod synchronization signal, and a data acquisition and operation unit. The arc length of the graphite arc plate air slot is the detection area length of the cigarette rod; The throttling intake nozzle is a hollow tube with a constant diameter. A small-hole section is arranged inside the hollow tube. The small-hole section is a partition plate with a through hole on it. The thickness of the partition plate is L1. At least one micropore with a diameter d of 0.1 - 0.7 mm is set in the area near the center of the partition plate. When L1 / d satisfies 0.5 < L1 / d ≤ 6 to form a short hole, an element with an air-flow throttling effect is formed.

[0022] A device for on-line detecting the ventilation degree of cigarette rods includes an air inlet pipe, a throttling intake nozzle, a detecting drum, graphite arc plates arranged on both sides of the detecting drum, an air groove is arranged on the side of the graphite arc plate corresponding to the cigarette rod, a cigarette rod synchronous signal, and a data acquisition and operation unit. The air path of the air groove is communicated with pressure sensors at the air inlet pipe, the air inlet end graphite arc plate and the air outlet end graphite arc plate of the cigarette rod. It is characterized in that the arc length of the air groove of the graphite arc plate is the detection area length of the cigarette rod. The throttling intake nozzle is a hollow tube with a reduced-diameter section, a small-hole section and an enlarged-diameter section arranged inside. The reduced-diameter section is the air inlet section, the enlarged-diameter section is the air outlet section, the length of the small-hole section is L2, and the hole diameter is D. It is a slender hole. When the length of the small-hole section is 3 - 15 mm and the hole diameter range is 0.2 mm to 2.5 mm, a Venturi tube is formed, and a lower pressure is obtained in its enlarged-diameter section, and it has the function of stabilizing the air-flow pressure.

[0023] After acquiring the cigarette rod synchronous signal, the data acquisition and operation unit calculates the pulse period of the signal. After avoiding the time period when the air pressure and air flow are unstable in the detection area of the air inlet and outlet grooves of the cigarette rod, it is frequency-divided N times to form N detection trigger pulses, forming an effective electrical detection area. The pressure sensor generates a detection data corresponding to each detection trigger pulse, and performs an average calculation on the N detection values to obtain the accurate pressure values at the air inlet end and air outlet end of the cigarette rod, and further obtains a more accurate ventilation degree value of the cigarette rod.

[0024] The combination of the throttling intake nozzle for stabilizing air flow and air pressure and the effective electrical detection area realizes α of 5% - 45%, thereby expanding the length of the effective detection area. The device for online cigarette ventilation accuracy detection includes a throttling inlet nozzle. The throttling nozzle contains a hollow tube with a narrowed section, a small-hole section, and an expanded section arranged sequentially. The narrowed section is the inlet section, the expanded section is the outlet section, and the small-hole section is of equal diameter. A microporous baffle is installed within the small-hole section. The device combines a constant flow and constant pressure airflow nozzle. The small-hole section has a length L2 and a diameter D, forming a long, narrow orifice. The orifice section is 3-15 mm long and has a diameter ranging from 0.2 mm to 2.5 mm. The microporous baffle is located at the junction of the small-hole section's airflow outlet and the expanded section. The baffle is located within the orifice diameter of the small-hole section or within the expanded section's range and has at least one small hole with a diameter of 0.15-0.8 mm. The inlet airflow pressure is contracted by the narrowed section, resulting in increased velocity and decreased pressure. This creates a relatively constant low-pressure zone near the microporous outlet of the baffle. The microporous baffle, with its throttling function, then achieves a constant pressure and constant flow effect.

[0025] Compared with the prior art, the present invention has the following beneficial effects: The reduction in the installation of shaft encoders and the use of their associated professional signal acquisition and processing modules lowers equipment costs. The steps for detecting trigger pulses in calculations have been simplified, the process of the calculation software has been streamlined, and the calculation speed has been improved. The detection parameters that cause air pressure fluctuations when cigarettes enter and leave the detection area are not detected, thus forming an effective electrical detection area, reducing the amount of data processing and improving the acquisition efficiency. The detection parameters are only tested after the air pressure has stabilized once the cigarette enters the detection area, which improves detection efficiency, the validity of detection data, and the accuracy of detection parameters.

[0026] By using a human-machine interface to input the positioning delay parameters for data acquisition, the device becomes more flexible to use and human-machine communication becomes more efficient.

[0027] By combining the electrical testing area with the throttle nozzle, the effective testing area length is increased, thereby obtaining more reliable testing data. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of existing technology; Figure 2 and Figure 3 This is a schematic diagram of the structure of the present invention; Figure 4 and Figure 5 This is a schematic diagram of the detection method; Figure 6.1 , Figure 6.2 , Figure 6.3 and Figure 7 This is a schematic diagram of the small air intake nozzle. Figure 8 A schematic diagram of the air pressure fluctuation data curve for cigarettes entering and leaving the detection area; Detailed Implementation

[0029] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0030] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0031] An online cigarette ventilation detection device may consist of: an air inlet pipe, a detection drum, graphite arc plates located on both outer sides of the detection drum, pressure sensors installed at the air inlet and outlet ends of the graphite arc plates, a cigarette synchronization signal, and a data acquisition and processing unit. Alternatively, it can consist of: an air inlet pipe, an air inlet nozzle, a detection drum, graphite arc plates located on both sides of the detection drum, and pressure sensors installed at the air inlet and outlet ends of the graphite arc plates, a cigarette synchronization signal, and a data acquisition and processing unit. The pressure sensors installed at the air inlet and outlet ends of the graphite arc plates on both sides of the detection drum detect the pressure values ​​at the lit end and the filter end of the cigarette under the coordination of the detection trigger pulse. After acquiring the cigarette synchronization signal, the data acquisition and processing unit calculates the pulse period of the signal, removes the fluctuation data when the cigarette enters or leaves the detection area, and then performs N frequency divisions to form N detection trigger pulses. The pressure sensor generates a detection data for each detection trigger pulse. The average of N detection values ​​is calculated to obtain accurate pressure values ​​at the inlet and outlet of the cigarette, and the accurate ventilation value of the cigarette is obtained from the air intake.

[0032] The cigarette synchronization signal includes a pulse signal from the cigarette position sensor and a pulse signal from the machine clock. The cigarette synchronization signal corresponds to the speed and position of each cigarette. Preferably, only one synchronization pulse is generated for each cigarette.

[0033] Based on the cigarette synchronization signal, the data acquisition and processing unit performs the following calculations when the cigarette rolling machine speed exceeds 1000 cigarettes / minute: ① Obtain the duration period T between the synchronization signals of two adjacent cigarettes; ② Set the delay from the initial rising edge of the cigarette synchronization pulse to the rising edge of the first allowable detection pulse, with a coefficient of α (0-50%), preferably 5%-10%; ③ Set the delay from the rising edge of the cigarette synchronization pulse to the end of the last detection pulse cycle, with a coefficient of β (10-70%), preferably 10%-65%; ④ Obtain the effective detection time length: T1 = (β - α) * T; ⑤ Set the number of pressure sensor data acquisitions N and the pulse duty cycle N1 required within time T1 to obtain the detection trigger pulse with a period of T2=T1 / N and a duty cycle of N1%; ⑥ After a delay of α from the rising edge of the cigarette synchronization pulse, the operation and control unit issues an allow detection pulse, which is a sequence of N allow detection pulses with a period of T1 / N and a duty cycle of N1%.

[0034] ⑦ The data acquisition unit collects data from the pressure sensors at the air inlet end of the two pairs of air inlet slots and the air outlet end of the air outlet slot according to the detection trigger pulse issued by the arithmetic control unit, and obtains data from N pressure sensors corresponding to each cigarette, namely N data for P1 inlet, P1 outlet, and P2 inlet, P2 outlet.

[0035] ⑧ Calculate the average value of the above N valid data for each pressure sensor: P = (P1 + ~ - + PN) / N, which means P1 in average, P1 out average, and P2 in average, P2 out average. ⑧ If the air inlet ends of the two sets of air inlet slots correspond to the ignition end of the cigarette, and the air outlet ends of the two sets of air outlet slots correspond to the filter end of the cigarette, then both sets of detection adopt forward detection airflow, and the airflow flows from the ignition end of the cigarette to the filter end of the cigarette.

[0036] Consequently, we obtain: P_in average = (P1_in average + P2_in average) / 2 P_average = (P_1 average + P_2 average) / 2 The ventilation of a cigarette is F = (Pin average - Pout average). Alternatively: The ventilation of the cigarette is F = (P_in average - P_out average) / P_in average.

[0037] ⑨ If the air inlet end of one set of air inlets corresponds to the lit end of the cigarette and the air outlet end of the air outlet corresponds to the filter end of the cigarette (forward detection of airflow, i.e., the detection of airflow from the lit end of the cigarette to the filter end of the cigarette), and the air inlet end of another set of air inlets corresponds to the filter end of the cigarette and the air outlet end of the air outlet corresponds to the lit end of the cigarette (reverse detection of airflow, i.e., the airflow from the filter end of the cigarette to the lit end of the cigarette). Consequently, we obtain: The forward ventilation of the cigarette is F_positive = (P1 in average * C1 - P1 out average * C2), or F_positive = (P1 in average * C1 - P1 out average * C2) / P1 in average; The reverse ventilation degree F_anti of the cigarette rod = (average P2_in * C3 - average P2_out * C4), or F_anti = (average P2_in * C3 - average P2_out * C4) / average P2_in. C1, C2, C3, and C4 are adjustment coefficients, which are adjustment constants required for monitoring parameter calibration.

[0038] The application of the above operations and methods can achieve the function of replacing the shaft encoder, and the installation is simple and fast. Moreover, there is no need to use software and hardware to judge invalid data, which simplifies the system design and reduces costs. The average value calculation method reduces the measurement and calculation errors caused by factors such as air pressure fluctuations, machine operation fluctuations, and cigarette rod jitters.

[0039] ⑨ The forward filter tip ventilation degree of the cigarette rod: Fv1 = β1 * F_forward, where β1 is the set adjustment coefficient; The reverse filter tip ventilation degree of the cigarette rod: Fv2 = β2 * F_anti, where β2 is the set adjustment coefficient; The filter tip ventilation degree of the cigarette rod: PV = Fv1 * C1 + Fv2 * C2.

[0040] Note: Due to the limitations of the structure of the on-line detection instrument, it is impossible to directly detect the filter tip ventilation degree of the cigarette rod. Considering that the ventilation degree of the whole cigarette rod has been detected in this article, and the ventilation degree of the burning section of the cigarette rod is relatively fixed. Through a large number of data tests, the adjustment coefficients of C1 and C2 are given, so as to realize the on-line detection of the filter tip ventilation degree.

[0041] Synchronous signal transformation and sampling operation process In order to reduce such airflow fluctuations, a technical solution of constant pressure air supply combined with a small hole nozzle is usually adopted. A certain resistance (small hole resistance) is preset for the air flow path, so as to reduce the fluctuations in air pressure caused by the cigarette rod entering and leaving the detection area. Although certain effects are achieved, the air pressure oscillation cannot be completely eliminated, which further affects the stable detection of parameters.

[0042] One form of the small hole nozzle: It is arranged at the air flow inlet at the intake end of the graphite arc plate, and is composed of a gradually shrinking intake section, a small hole section, and a gradually expanding outlet section.

[0043] The small hole section is composed of at least one ventilation small hole, and the aperture of the small hole is 0.1 mm to 2.5 mm, preferably 0.1 to 1.2 mm, so as to form a preset high resistance to the intake air flow (described in the relevant equipment manual), and is used to form a stable air flow at the outlet end of the small hole that is not affected by subsequent factors, constituting the detection element of constant flow for cigarette rod detection, and forming an air flow rate of 17.5 ml / s; Or preferably 0.3 to 1.8 mm, so as to form a preset resistance to the intake air flow, for forming a stable air pressure at the outlet end of the small holes that is not affected subsequently, and cooperating with the draw resistance of the cigarette itself to constitute the detection elements of constant pressure and constant current for cigarette detection, thereby forming a stable air flow pressure value; Another form of the small hole nozzle: The throttling intake nozzle is a hollow tube, and a small hole section is arranged inside the hollow tube. The small hole section is a partition plate provided with through holes. The thickness of the partition plate is L1, and at least one micropore with a diameter d: 0.1 - 0.7 mm is set in the area near the center of the partition plate. When L1 / d satisfies: 0.5 < L1 / d ≤ 6 to form a short hole, an element with an air flow throttling effect is formed; An on-line device for detecting the ventilation degree of cigarettes, characterized in that: the constant pressure throttling intake nozzle is a hollow tube provided with a reduced diameter section, a small hole section and an enlarged diameter section that are sequentially connected to each other. The reduced diameter section is the intake section, the enlarged diameter section is the outlet section, the length of the small hole section is L2, and the aperture is D, which is a slender hole. When the length of the small hole section is 3 - 8 mm and the aperture range is 0.8 mm to 2.5 mm, a Venturi tube is formed, and a lower pressure is obtained in its enlarged diameter section, and it has the function of stabilizing the air flow pressure; A combination with a constant current and constant pressure air flow nozzle: The small hole partition plate is arranged at the junction of the air flow outlet end of the small hole section and the enlarged diameter section. The intake pressure is contracted by the reduced diameter section, the speed increases and the pressure decreases, so as to generate a relatively constant low pressure area near the partition plate, and then a micropore partition plate with a throttling function is used to achieve the effect of constant pressure and constant current.

[0044] Furthermore, when the cigarette enters and exits the detection area stably, the fluctuations or oscillations of the detection pressure and detection air flow caused by the opening and closing of the air flow are achieved.

[0045] Mathematical model: Flow rate Qin = (Pin - Pout) / (R resistance + R load), Due to the entry and exit of the cigarette in the detection area, the pulsation of the air pressure and air flow is caused, that is, the fluctuation of R load is formed, resulting in the fluctuation of the flow rate Qin, and the detection parameters are inaccurate.

[0046] If R resistance >> R load: When R load fluctuates, the change of R resistance + R load is not large, and then the flow rate Qin = (Pin - Pout) / (R resistance + R load) = constant value.

[0047] Ensure the stability and accuracy of the detection parameters.

[0048] The reasons for setting adjustment parameters such as C1, C2, C3, C4, etc. are as follows: The draw resistance and ventilation degree of cigarettes are defined as follows: The determination definition and measurement principle of the draw resistance of cigarettes and the pressure drop of filter rods: Where draw resistance is defined as: The cigarette is sealed in the measuring device, with the output end inserted to a depth of 9 mm. Under the standard conditions of GB / T 16447, the output end flow rate is maintained at 17.5 mL / s while a constant airflow rate with negative pressure is applied to the output end.

[0049] A constant negative pressure airflow of 17.5 ml / s needs to be generated at the nozzle end. The standard total ventilation or filter nozzle ventilation value can be obtained by comparing the segmented measured airflow with 17.5 ml / s.

[0050] Therefore, the national standard corresponds to negative pressure suction testing, with a constant airflow of 17.5 ml / s. However, in actual online measurements, negative pressure testing can draw in environmental dust, cigarette residue, or grime from the cigarette tip, causing sensor inaccuracy or blockage. Therefore, current testing methods use positive pressure airflow with constant pressure and flow to simulate data obtained under laboratory conditions. Thus, it is essential to first obtain a pressure value with minimal fluctuations and high accuracy. Then, the sensor is calibrated based on laboratory data, using adjustment coefficients C1, C2, C3, and C4 to correct the actual test data and simulate cigarette ventilation and suction resistance.

[0051] The reason for adding a small-aperture nozzle: The air pressure fluctuation data curves before and after using a small-aperture nozzle in the detection area of ​​the cigarette entering and exiting the detection area are as follows: Figure 8 : It is evident that using a small-orifice nozzle can indeed stabilize air pressure and create a constant flow rate, thereby reducing fluctuations in air pressure and airflow caused by cigarettes entering and leaving the detection area, expanding the stable area of ​​air pressure and airflow, and increasing the effective working time of the sensor.

[0052] Technical effects: The reduction in the installation of shaft encoders and the use of their associated professional signal acquisition and processing modules lowers equipment costs. The steps for detecting trigger pulses in calculations have been simplified, the process of the calculation software has been streamlined, and the calculation speed has been improved. The detection parameters that cause air pressure fluctuations when cigarettes enter and leave the detection area are not detected, which reduces the amount of data processing and improves the collection efficiency. The detection parameters are only tested after the air pressure has stabilized once the cigarette enters the detection area, which improves detection efficiency, the validity of detection data, and the accuracy of detection parameters.

[0053] By using a human-machine interface to input the positioning delay parameters for data acquisition, the device becomes more flexible to use and human-machine communication becomes more efficient.

[0054] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for improving the accuracy of online cigarette ventilation detection, comprising: The device comprises an air inlet pipe, a detection drum, graphite arc plates disposed on both sides of the detection drum, an air groove disposed on the side of the graphite arc plate corresponding to the cigarette, a cigarette synchronization signal, and a data acquisition and processing unit. The air path of the air groove is connected to the pressure sensors at the air inlet pipe and the graphite arc plate at the air outlet of the cigarette. The device is characterized in that the arc length of the air groove of the graphite arc plate is the length of the detection area of ​​the cigarette. After acquiring the cigarette synchronization signal, the data acquisition and processing unit calculates the pulse period of the signal. After avoiding the period of unstable air pressure and airflow when the cigarette enters or exits the air groove detection area, it performs N frequency divisions to form N detection trigger pulses. The stable air pressure and airflow period is obtained through the effective detection time length: T1. Based on the cigarette synchronization signal, when the cigarette machine speed is greater than X cigarettes / minute, the data acquisition and processing unit performs the following calculations, where X is a positive integer greater than 100: S1, obtain the duration period T between two adjacent cigarette synchronization signals, and use a dual-channel oscilloscope to simultaneously detect the waveforms of the cigarette synchronization signal and the voltage signal of the pressure sensor; S2, Based on the graph displayed on the oscilloscope, set the delay from the initial rising edge of the cigarette synchronization pulse to the rising edge of the first allowable detection pulse, with a coefficient of α: 30-65%; S3, Based on the graph displayed on the oscilloscope, set the delay from the first rising edge of the cigarette synchronization pulse to the end of the last detection pulse cycle, with a coefficient of β: 40-98%; S4, obtain the effective detection time length: T1 = (β-α) * T; S5, set the number of pressure sensor data acquisitions N and pulse duty cycle N1 required within time T1, and obtain a detection trigger pulse with period T2=T1 / N and duty cycle N1%; S6, after a delay of α from the rising edge of the cigarette synchronization pulse, the operation and control unit issues an allow detection pulse, which is a sequence of N allow detection pulses with a period of T1 / N and a duty cycle of N1%. S7, the data acquisition unit collects data from the pressure sensors at the air inlet end of the two pairs of air inlet slots and the air outlet end of the air outlet slot according to the detection trigger pulse issued by the calculation control unit, and obtains data from N pressure sensors corresponding to each cigarette, namely N data for P1 inlet, P1 outlet, and P2 inlet, P2 outlet. S8, calculate the average value of the above N data points for each pressure sensor: By using P = (P1 + ... + PN) / N, we can obtain the average of P1 entering and P1 exiting, and the average of P2 entering and P2 exiting. S9. If the air inlet ends of the two pairs of air inlet slots correspond to the ignition end of the cigarette and the air outlet ends of the two pairs of air inlet slots correspond to the filter end of the cigarette, then both sets of detection adopt forward detection airflow, and the airflow flows from the ignition end of the cigarette to the filter end of the cigarette. Consequently, we obtain: P_in average = (P1_in average + P2_in average) / 2 P_average = (P_1 average + P_2 average) / 2 The ventilation rate of the cigarette is F = (Pin average - Pout average). Alternatively: The ventilation of the cigarette stick F = (average P inlet - average P outlet) / average P inlet; S10. If the intake end of a group of intake slots corresponds to the lit end of the cigarette and the outlet end of the outlet slot corresponds to the filter tip end of the cigarette, the air flow is detected in the forward direction, that is, the detected air flow flows from the lit end of the cigarette to the filter tip end of the cigarette. If the intake end of the other group of intake slots corresponds to the filter tip end of the cigarette and the outlet end of the outlet slot corresponds to the lit end of the cigarette, the air flow is detected in the reverse direction, that is, the air flow flows from the filter tip end of the cigarette to the lit end of the cigarette. Furthermore, obtain: The forward ventilation degree F_forward of the cigarette = (P1_in_average * C1 - P1_out_average * C2), Or F_forward = (P1_in_average * C1 - P1_out_average * C2) / P1_in_average, The reverse ventilation degree F_reverse of the cigarette = (P2_in_average * C3 - P2_out_average * C4), Or F_reverse = (P2_in_average * C3 - P2_out_average * C4) / P2_in_average, C1, C2, C3, and C4 are adjustment coefficients, which are adjustment constants required for monitoring parameter calibration; S11. The forward filter tip ventilation degree of the cigarette: Fv1 = β1 * F_forward, where β1 is a set adjustment coefficient. The reverse filter tip ventilation degree of the cigarette: Fv2 = β2 * F_reverse, where β2 is a set adjustment coefficient. The filter tip ventilation degree of the cigarette: PV = Fv1 * C1 + Fv2 * C2.

2. The method for improving the accuracy of online cigarette ventilation detection according to claim 1, characterized in that: The cigarette synchronization signal includes the pulse signal of the cigarette in-place sensor and the pulse signal of the machine clock, and the cigarette synchronization signal corresponds to the speed and position of each cigarette.

3. The method for improving the accuracy of online cigarette ventilation detection according to claim 1, characterized in that: Each cigarette corresponds to only one pulse of the cigarette synchronization signal.

4. The method for improving the accuracy of online cigarette ventilation detection according to claim 1, characterized in that: The pressure values corresponding to the pressure sensors arranged at the graphite arc plate at the intake end of the cigarette and the graphite arc plate at the outlet end of the cigarette are: Pin is the value of the pressure sensor at the intake end of the cigarette, and Pout is the value of the pressure sensor at the outlet end of the cigarette. When the cigarette enters or leaves the detection area of the circular arc air groove of the graphite arc plate, the change rate of Pin and Pout is within the range of 4.8% - 9%.

5. The method for improving the accuracy of online cigarette ventilation detection according to claim 1, characterized in that: In S2, the coefficient α is 40% - 55%.

6. The method for improving the accuracy of online cigarette ventilation detection according to claim 1, characterized in that: In S3, the coefficient β is 45% - 85%.

7. An apparatus for improving the accuracy of online cigarette ventilation detection using the method of claim 1, characterized in that: It includes: An intake pipe, a throttle intake nozzle, a detection drum, graphite arc plates arranged on both sides of the detection drum, pressure sensors arranged at the graphite arc plate at the intake end of the cigarette and the graphite arc plate at the outlet end of the cigarette, a cigarette synchronization signal, and a data acquisition and calculation unit. It is characterized in that: the arc length of the graphite arc plate air groove is the detection area length of the cigarette; The throttle intake nozzle is an equal-diameter hollow pipe, and a small hole section is arranged in the hollow pipe. The small hole section is a partition plate with through holes on it. The thickness of the partition plate is L1, and at least one micropore with a diameter d: 0.1 - 0.7 mm is set in the area near the center of the partition plate. L1 / d satisfies: 0.5 < L1 / d ≤ 6, forming a short hole to form an element with an air flow throttling effect.

8. An apparatus for improving the accuracy of online cigarette ventilation detection using the method of claim 1, comprising: An intake pipe, a throttle intake nozzle, a detection drum, graphite arc plates arranged on both sides of the detection drum, an air groove is arranged on the side of the graphite arc plate corresponding to the cigarette, a cigarette synchronization signal, and a data acquisition and calculation unit. The air path of the air groove is connected to the intake pipe and the pressure sensors at the graphite arc plate at the intake end of the cigarette and the graphite arc plate at the outlet end of the cigarette. It is characterized in that: the arc length of the graphite arc plate air groove is the detection area length of the cigarette; The throttling intake nozzle is a hollow tube with a narrowing section, a small orifice section, and an expanding section. The narrowing section is the intake section, the expanding section is the outlet section, and the small orifice section is a slender orifice. When the length of the small orifice section is 3-15mm and the orifice diameter ranges from 0.2mm to 2.5mm, it forms a venturi tube. The expanding section obtains a lower pressure and has the function of stabilizing the airflow pressure. After acquiring the cigarette synchronization signal, the data acquisition and processing unit calculates the pulse period of the signal. After avoiding the period when the air pressure and airflow are unstable when the cigarette enters or exits the gas groove detection area, it performs N frequency divisions to form N detection trigger pulses, thus forming an effective electrical detection area. The pressure sensor generates a detection data for each detection trigger pulse. The average of N detection values ​​is calculated to obtain accurate pressure values ​​at the inlet and outlet of the cigarette, thereby obtaining a more accurate value for the cigarette ventilation. The combination of a throttling air intake nozzle that stabilizes airflow and pressure with an effective electrical detection zone achieves an α value of 5%-45%, thereby expanding the length of the effective detection area.

9. An apparatus for improving the accuracy of online cigarette ventilation detection using the method of claim 1, characterized in that: The nozzle includes a throttling intake nozzle, which is a hollow tube with a reduced diameter section, a small orifice section, and an expanded diameter section arranged sequentially inside the nozzle. The reduced diameter section is the intake section, the expanded diameter section is the outlet section, and the small orifice section is a constant diameter section. The small orifice section is equipped with a microporous baffle, and the nozzle is a combination of constant flow and constant pressure airflow nozzles. The small hole segment is an elongated hole, with a length of 3-15mm and a diameter ranging from 0.2mm to 2.5mm. The microporous baffle is located at the junction of the airflow outlet end of the small-hole section and the expansion section. The microporous baffle has at least one small hole with a diameter of 0.15-0.8mm. The intake airflow pressure is contracted by the reduction section, the speed increases and the pressure decreases, thereby creating a constant low-pressure zone near the microporous outlet of the baffle. By utilizing the microporous baffle with throttling function, the effect of constant pressure and constant flow is achieved.

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