A glue spraying adjustment system and method based on spectral confocal technology

Abstract

The application discloses a glue spraying adjusting system and method based on a spectral confocal technology, and the system comprises a spectral confocal sensor, a spraying unit, a system control unit and a hydraulic control unit, the system control unit is connected with the spectral confocal sensor, the spraying unit and the hydraulic control unit respectively, the spectral confocal sensor is used for transmitting the obtained thickness information to the system control unit, the spraying unit is used for spraying glue on one side of a cigarette paper band so as to make the two sides of the cigarette paper band adhere to each other, the system control unit is used for making corresponding instructions to the hydraulic control unit according to the glue coating thickness signal obtained by the spectral confocal sensor and the rotating speed signal of cigarette paper roll forming, and the hydraulic control unit is used for adjusting the pressure threshold of a pressure reducing valve contained in the hydraulic control unit after receiving the corresponding instructions of the system control unit, so that the spraying unit can produce a constant and uniform glue coating thickness.

Description

Technical Field

[0001] This invention belongs to the field of tobacco machinery and equipment technology, specifically relating to a spray adhesive adjustment system and method based on spectral confocal technology. Background Technology

[0002] Cigarette paper wraps around tobacco shreds and is rolled into a cigarette pack as it moves through the flue. During this process, an adhesive nozzle evenly sprays adhesive onto one side of the cigarette paper, allowing the two sides of the cigarette paper to adhere together. When the speed of the cigarette rolling machine changes suddenly or when adhesive is manually added, the thickness of the adhesive layer will change accordingly, resulting in poor adhesion or adhesive overflow, which can cause quality defects such as cigarette popping. Summary of the Invention

[0003] To address the aforementioned technical problems in existing technologies, this invention provides a spray adhesive adjustment system and method based on spectral confocal technology. This invention uses a spectral confocal sensor to collect adhesive layer thickness information in real time, imports it into the system control unit, and, in conjunction with the cigarette machine's rotation speed, adjusts the pressure threshold of the pressure reducing valve. This reduces disturbances to the adhesive thickness caused by various factors during the adhesive application process, thereby achieving uniform adhesive application.

[0004] The technical solution adopted in this invention is:

[0005] A glue spraying adjustment system based on spectral confocal technology is characterized by comprising a spectral confocal sensor, a spraying unit, a system control unit, and a hydraulic control unit, wherein the system control unit is respectively connected to the spectral confocal sensor, the spraying unit, and the hydraulic control unit for controllable connection; wherein:

[0006] The spectral confocal sensor is installed perpendicular to the conveying direction of the cigarette paper tape. It monitors and provides feedback on the thickness information of the coating layer of the cigarette in real time and transmits the monitored thickness information to the system control unit.

[0007] The spraying unit sprays glue onto one side of the cigarette paper strip to bond the two sides of the cigarette paper strip together.

[0008] The system control unit issues corresponding commands to the hydraulic control unit based on the coating thickness signal monitored by the spectral confocal sensor and the rotation speed signal of the cigarette paper rolling process.

[0009] The hydraulic control unit receives corresponding instructions from the system control unit and adjusts the pressure threshold of its pressure reducing valve to achieve a constant and uniform coating thickness in the spraying unit.

[0010] Furthermore, the spectral confocal sensor is disposed inside a light-shielding container, and a small hole is provided at the bottom of the light-shielding container. The detection end of the spectral confocal sensor is disposed through the small hole and connected to the cigarette paper strip.

[0011] Furthermore, the spectral confocal sensor also includes a filtering circuit to reduce signal interference after filtering the detected thickness signal.

[0012] Furthermore, the hydraulic control unit includes a servo pneumatic valve, a glue supply pump, and a pressure reducing valve. The control terminal of the servo pneumatic valve is connected to the system control unit, the glue supply pump is connected to the pressure reducing valve, and the output terminal of the servo pneumatic valve controls the pressure threshold of the pressure reducing valve. The output terminal of the servo pneumatic valve is connected to the pressure threshold adjustment terminal of the pressure reducing valve through an oil circuit. When the control terminal of the servo pneumatic valve receives a signal from the system control unit, it changes the opening degree and adjusts the spring compression of the pressure reducing valve. The pressure threshold of the pressure reducing valve is controlled by the spring compression.

[0013] Furthermore, the inner wall of the glue spray nozzle of the glue spraying unit is coated with an anti-stick coating, and a heating device is installed around the glue spray nozzle.

[0014] A method for adjusting adhesive spraying based on spectral confocal technology, characterized in that the circuit of the system control unit is designed according to the following formula:

[0015]

[0016] Where h is the thickness of the adhesive layer;

[0017] C d The orifice flow coefficient was determined experimentally.

[0018] B is the width of the adhesive layer. Since the nozzle is close to the adhesive application area, the fluid jet can be ignored, i.e., the nozzle diameter.

[0019] v is the linear speed at which the cigarette paper is rolled into shape, a parameter obtained from the cigarette rolling machine;

[0020] Δp is the pressure difference between the two ends of the glue spray nozzle;

[0021] ρ is the density of the glue;

[0022] The steps for determining the pressure difference ΔP across the nozzle to meet the standard adhesive coating thickness are as follows:

[0023] a) Obtain the standard thickness H of the adhesive layer from the product standard; the density ρ of the tobacco adhesive is provided by the manufacturer.

[0024] b) The flow coefficient C of the spray nozzle orifice was determined experimentally. d ;

[0025] c) Measure the diameter B of the spray nozzle using vernier calipers;

[0026] d) When the cigarette machine reaches a certain constant speed, record the linear velocity v of the cigarette paper forming process on the display screen at this time;

[0027] e) Adjust the flow rate of the glue supply pump at the linear velocity v in step d above until the spectral confocal sensor detects a glue coating thickness of H;

[0028] f) Use a pressure gauge to measure the pressure ΔP of the glue supply pipe at the glue nozzle end;

[0029] g) Determine ΔP at this time:

[0030]

[0031] When the system control unit receives the coating thickness signal and the linear velocity signal, it obtains the current pressure value, compares it with the target pressure difference at the current linear velocity, and obtains the change in pressure difference. This change is then converted into the deformation signal of the pressure reducing valve threshold adjustment spring, thereby realizing the control of the pressure difference at the spray nozzle.

[0032] Furthermore, in step b), the flow coefficient C of the nozzle is... d The measurement process is as follows:

[0033] 1. Determine the Reynolds number (Re) of the tobacco adhesive during normal operation of the cigarette rolling machine.

[0034] Re = ρV 胶 B / γ

[0035] Where ρ is the glue density, γ is the glue dynamic viscosity, both of which can be provided by the manufacturer, and V 胶 The glue flow rate under this working condition can be measured using a venturi tube;

[0036] B is the diameter of the glue spray nozzle, measured with vernier calipers;

[0037] Measurements showed that Re < 10 at the maximum operating speed of the cigarette rolling machine. 5

[0038] 2: Since the glue is in a fully contracted, flowing state, an empirical formula can be used:

[0039] C d =0.964Re -0.05 .

[0040] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0041] By feeding back real-time information on the coating thickness and the speed at which cigarette paper is rolled to the system control unit, the hydraulic system is controlled according to the built-in logic in the circuit to adjust the pressure difference at both ends of the glue spray nozzle, thereby achieving uniform glue coating. Attached Figure Description

[0042] Figure 1 This is the circuit diagram of the glue spraying adjustment system.

[0043] Figure 2 This is a system diagram of the system control unit.

[0044] Figure 3 It is a flowchart for determining the relationship between pressure difference and linear velocity under standard adhesive layer thickness.

[0045] Figure 4 This is a partial cross-sectional view of a pressure reducing valve, mainly used to illustrate the principle of adjusting the pressure threshold.

[0046] The reference numerals in the attached figures are as follows:

[0047] 1. Spectral confocal sensor; 2. Spraying unit; 3. Pressure reducing valve; 4. Servo pneumatic valve; 5. System control unit; 6. Cigarette paper tape. Detailed Implementation

[0048] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0049] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0050] The present invention will now be described in detail with reference to the accompanying drawings and exemplary embodiments.

[0051] refer to Figures 1 to 3 The present invention discloses a glue spraying adjustment system based on spectral confocal technology, comprising a spectral confocal sensor 1, a spraying unit 2, a system control unit 5, and a hydraulic control unit. The system control unit 5 is respectively connected to the spectral confocal sensor 1, the spraying unit 2, and the hydraulic control unit.

[0052] The spectral confocal sensor 1 is installed perpendicular to the conveying direction of the cigarette paper tape. It monitors and provides feedback on the thickness information of the coating layer of the cigarette in real time and transmits the monitored thickness information to the system control unit.

[0053] Spraying unit 2 sprays glue onto one side of the cigarette paper strip to bond the two sides of the cigarette paper strip together.

[0054] The system control unit 5 issues corresponding instructions to the hydraulic control unit based on the coating thickness signal monitored by the spectral confocal sensor and the rotation speed signal of the cigarette paper rolling process.

[0055] The hydraulic control unit receives corresponding instructions from the system control unit and adjusts the pressure threshold of its pressure reducing valve to achieve a constant and uniform coating thickness in the spraying unit.

[0056] In one embodiment, the spectral confocal sensor 1 is disposed inside a light-shielding container, the bottom of which has a small hole, and the detection end of the spectral confocal sensor 1 is disposed through the small hole and connected to the cigarette paper strip.

[0057] In one embodiment, the spectral confocal sensor 1 further includes a filtering circuit to reduce signal interference after filtering the detected thickness signal.

[0058] Specifically, the spectral confocal sensor is used to detect thickness fluctuations in the adhesive coating. To further improve detection accuracy, the sensor is placed in a light-shielding container to prevent external natural light from affecting the detection signal. Because the thickness of the adhesive coating is on the micrometer scale, high accuracy is required, so the detected thickness signal also needs to be processed by a filtering circuit to further reduce noise interference.

[0059] In one embodiment, the hydraulic control unit includes a servo pneumatic valve 4, a glue supply pump, and a pressure reducing valve 3. The control terminal of the servo pneumatic valve 4 is connected to the system control unit 5, and the glue supply pump is connected to the pressure reducing valve 3. The output terminal of the servo pneumatic valve 4 controls the pressure threshold of the pressure reducing valve 3. The output terminal of the servo pneumatic valve 4 is connected to the pressure threshold adjustment terminal of the pressure reducing valve 3 through an oil circuit. When the control terminal of the servo pneumatic valve 4 receives a signal from the system control unit 5, it changes the opening degree and adjusts the spring compression of the pressure reducing valve 3. The pressure threshold of the pressure reducing valve 3 is controlled by the spring compression.

[0060] In one embodiment, the inner wall of the spray nozzle of the glue spraying unit 2 is coated with an anti-stick coating, and a heating device is installed around the spray nozzle.

[0061] A method for adjusting adhesive spraying based on spectral confocal technology, characterized in that the circuit of the system control unit is designed according to the following formula:

[0062]

[0063] Where h is the thickness of the adhesive layer;

[0064] C d The orifice flow coefficient was determined experimentally.

[0065] B is the width of the adhesive layer. Since the nozzle is close to the adhesive application area, the fluid jet can be ignored, i.e., the nozzle diameter.

[0066] v is the linear speed at which the cigarette paper is rolled into shape, a parameter obtained from the cigarette rolling machine;

[0067] Δp is the pressure difference between the two ends of the glue spray nozzle;

[0068] ρ is the density of the glue;

[0069] The steps for determining the pressure difference ΔP across the nozzle to meet the standard adhesive coating thickness are as follows:

[0070] h) Obtain the standard thickness H of the adhesive layer from the product standard; the density ρ of the tobacco adhesive is provided by the manufacturer.

[0071] i) The flow coefficient C of the spray nozzle orifice was determined experimentally. d ;

[0072] j) Measure the diameter B of the spray nozzle using vernier calipers;

[0073] k) When the cigarette machine reaches a certain constant speed, record the linear speed v of the cigarette paper forming process on the display screen;

[0074] l) Adjust the flow rate of the glue supply pump at the linear velocity v in step d above until the spectral confocal sensor detects the glue coating thickness as H;

[0075] m) Use a pressure gauge to measure the pressure ΔP of the glue supply pipe at the glue nozzle end;

[0076] n) Determine ΔP at this time:

[0077]

[0078] When the system control unit receives the coating thickness signal and the linear velocity signal, it obtains the current pressure value, compares it with the target pressure difference at the current linear velocity, and obtains the change in pressure difference. This change is then converted into the deformation signal of the pressure reducing valve threshold adjustment spring, thereby realizing the control of the pressure difference at the spray nozzle.

[0079] In one embodiment, in step b), the flow coefficient C of the nozzle is... d The measurement process is as follows:

[0080] 1. Determine the Reynolds number (Re) of the tobacco adhesive during normal operation of the cigarette rolling machine.

[0081] Re = ρV 胶 B / γ

[0082] Where ρ is the glue density, γ is the glue dynamic viscosity, both of which can be provided by the manufacturer, and V 胶 The glue flow rate under this working condition can be measured using a venturi tube;

[0083] B is the diameter of the glue spray nozzle, measured with vernier calipers;

[0084] Measurements showed that Re < 10 at the maximum operating speed of the cigarette rolling machine. 5

[0085] 2: Since the glue is in a fully contracted, flowing state, an empirical formula can be used:

[0086] C d =0.964Re -0.05 .

[0087] In this invention, the sensor feeds back the thickness fluctuation signal to the system control unit. The system control unit, combined with the current linear speed of the cigarette paper rolling process, transmits a control signal to the servo pneumatic valve according to its built-in logic. By changing the opening of the servo pneumatic valve, the stroke of the upper cylinder of the pressure reducing valve is altered. The cylinder acts on the compression spring of the pressure reducing valve, thus changing the pressure threshold of the valve by altering the spring compression. The servo pneumatic valve is used because of its fast response and the fact that it does not contaminate the adhesive in case of leakage. The flow rate of the spraying unit is determined by the pressure difference between the two ends. To prevent the adhesive from solidifying and clogging the spray nozzle due to prolonged downtime, a polytetrafluoroethylene coating is applied to the inner wall of the spray nozzle, and a heating device is installed around the nozzle.

[0088] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A spray adhesive adjustment system based on spectral confocal technology, characterized in that, The system includes a spectral confocal sensor, a spraying unit, a system control unit, and a hydraulic control unit. The system control unit is connected to the spectral confocal sensor, the spraying unit, and the hydraulic control unit, respectively. The spectral confocal sensor is installed perpendicular to the conveying direction of the cigarette paper tape. It monitors and provides feedback on the thickness information of the coating layer of the cigarette in real time and transmits the monitored thickness information to the system control unit. The spraying unit sprays glue onto one side of the cigarette paper strip to bond the two sides of the cigarette paper strip together. The system control unit issues corresponding commands to the hydraulic control unit based on the coating thickness signal and the linear speed signal of cigarette paper rolling obtained by the spectral confocal sensor. The hydraulic control unit receives the corresponding instructions from the system control unit and adjusts the pressure threshold of the pressure reducing valve to achieve a constant and uniform coating thickness in the spraying unit. The hydraulic control unit includes a servo pneumatic valve, a glue supply pump, and a pressure reducing valve. The control terminal of the servo pneumatic valve is connected to the system control unit, and the glue supply pump is connected to the pressure reducing valve. The output terminal of the servo pneumatic valve controls the pressure threshold of the pressure reducing valve. The output terminal of the servo pneumatic valve is connected to the pressure threshold adjustment terminal of the pressure reducing valve through an oil circuit. When the control terminal of the servo pneumatic valve receives a signal from the system control unit, it changes the opening degree and adjusts the spring compression of the pressure reducing valve. The pressure threshold of the pressure reducing valve is controlled by the spring compression. The circuit of the system control unit is designed according to the following formula: Where h is the thickness of the adhesive layer; C d The orifice flow coefficient was determined experimentally. B is the diameter of the glue spray nozzle; v is the linear speed at which the cigarette paper is rolled into shape, a parameter obtained from the cigarette rolling machine; Δp is the pressure difference across the nozzle; ρ is the density of the glue; When the system control unit receives the coating thickness signal and the linear velocity signal, it obtains the current pressure difference Δp, compares it with the target pressure difference at the current linear velocity, and obtains the change in pressure difference. This change is then converted into the deformation signal of the pressure threshold adjustment spring of the pressure reducing valve, thereby realizing the control of the pressure difference at the spray nozzle.

2. The adhesive spraying adjustment system based on spectral confocal technology as described in claim 1, characterized in that, The spectral confocal sensor is housed inside a light-shielding container, and the bottom of the light-shielding container has a small hole.

3. The adhesive spraying adjustment system based on spectral confocal technology as described in claim 2, characterized in that, The spectral confocal sensor also includes a filtering circuit to reduce signal interference after filtering the detected thickness signal.

4. The adhesive spraying adjustment system based on spectral confocal technology as described in claim 1, characterized in that, The inner wall of the spray nozzle of the spraying unit is coated with an anti-stick coating, and a heating device is installed around the spray nozzle.

5. The adhesive spraying adjustment system based on spectral confocal technology as described in claim 1, characterized in that, The orifice flow coefficient C d The experimental measurement process is as follows:

1. Determine the Reynolds number (Re) of the tobacco adhesive during normal operation of the cigarette rolling machine. Re = ρV 胶 B / c Where ρ is the glue density, γ is the glue dynamic viscosity, both provided by the manufacturer, and V 胶 The glue flow rate under this working condition was measured using a venturi tube. B is the diameter of the glue spray nozzle, measured with vernier calipers; Measurements show that at the maximum operating speed of the cigarette rolling machine, its Re < 10. 5 2: Since the glue is in a fully shrunk, flowing state, an empirical formula is used: C d = 0.964 Re -0.05 。

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