A method for estimating the position state of tobacco in a cut tobacco dryer

Abstract

The present application relates to a kind of tobacco position state estimation methods in cut tobacco dryer, by obtaining cut tobacco dryer equipment installation attribute parameter, calculate the single cycle residence time of tobacco in cylinder, calculate the residence position of tobacco in cylinder, after cut tobacco dryer is started and detects that tobacco enters cut tobacco dryer, every set time, update the position of tobacco head, after cut tobacco dryer detects that tobacco stops entering cut tobacco dryer, every set time, update the position of tobacco head.The present application gives a kind of tobacco position state estimation methods in cut tobacco dryer, mainly first calculate the single cycle residence time of tobacco in cut tobacco dryer, then calculate the forward distance of tobacco in single cycle according to the time, finally give the position judging mode of tobacco in material head and material tail stage, can be more accurate tobacco position, and then used for control logic improvement, provide information for more accurate moisture, temperature control of tobacco in cut tobacco dryer implementation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tobacco intelligent manufacturing, and particularly relates to a method for estimating the position state of cut tobacco in a cut tobacco dryer. BACKGROUND

[0002] Tobacco processing needs to go through multiple processes, among which the cut tobacco making process needs to unpack tobacco leaves and dry cut tobacco, and has an important influence on the quality of cigarettes. As a key step in cut tobacco making, the residence time and residence position of cut tobacco in the cut tobacco dryer largely determine the role of temperature control and moisture control in the cut tobacco dryer on the cut tobacco, and therefore it is necessary to accurately model the residence time and residence position of cut tobacco in the cut tobacco dryer. This is particularly important for the "material head" and "material level" corresponding to the start and stop of the cut tobacco dryer, and helps to reduce the proportion of low-quality or unqualified cut tobacco and improve production economic benefits.

[0003] In the prior art, the modeling method of cut tobacco residence time in a drum cut tobacco dryer is given in "Establishment and numerical simulation of cut tobacco residence time model in drum cut tobacco dryer", which considers two forms of cut tobacco movement in the drum: adhesion in the drum and free parabolic movement in the drum. However, the above assumption is ideal, and the internal structure of the cut tobacco dryer drum and the slow rotation speed result in multiple forms of cut tobacco movement in the drum, and therefore considering multiple forms of movement can improve the accuracy of the estimation of the residence time and residence position of cut tobacco.

[0004] The purpose of the present application is to approximately model the state of cut tobacco in the cut tobacco dryer by considering multiple forms of cut tobacco movement in the drum, to provide an estimation method for the residence time and residence position of cut tobacco in the cut tobacco dryer, to provide a basis for subsequent moisture and temperature control, and to provide information on cut tobacco quality for offline analysis. SUMMARY

[0005] The purpose of the present application is to provide a method for estimating the position state of cut tobacco in a cut tobacco dryer, which can dynamically and in real time estimate the residence position of cut tobacco in the cut tobacco dryer, and can display the processing state of cut tobacco in the cut tobacco dryer in real time, especially the processing state of cut tobacco when the cut tobacco dryer starts and stops, to provide information for more accurate moisture and temperature control of cut tobacco in the cut tobacco dryer.

[0006] To achieve the above purpose, the present application is implemented by the following technical scheme:

[0007] A method for estimating the position state of cut tobacco in a cut tobacco dryer, comprising the following steps:

[0008] S1, obtaining cut tobacco dryer equipment installation attribute parameters;

[0009] S2, calculate the single cycle residence time of the tobacco in the drum, that is, the time taken for the tobacco to return to the same position from the cross section to the position;

[0010] S3, calculate the residence position of the tobacco in the drum, the distance of the tobacco advancing to the outlet of the drum in the single cycle residence time includes two parts, one part is the displacement of the tobacco caused by the hot air blowing in the single cycle, and the other part is the displacement of the tobacco caused by the gravity component in the free-falling part, and the total displacement calculation relationship is:

[0011]

[0012] Wherein y k-1 represents the tobacco position at the last time, y k represents the tobacco position at the current time, is the displacement caused by the gravity component, is the displacement caused by the hot air blowing, wherein p V represents the medium density of the hot air, B represents the projection area of the tobacco particles in the direction perpendicular to the medium velocity, C represents the resistance coefficient, and v w represents the wind speed of the hot air.

[0013] The derivation formula of the current time velocity is:

[0014]

[0015] The meanings of the parameters in the above formula are the same as those in the foregoing;

[0016] S4, after the cut tobacco enters the cut tobacco machine, update the position of the cut tobacco head every time t, and the updating method is to update the residence position of the cut tobacco in the drum according to step (3);

[0017] S5, after the cut tobacco machine detects that the cut tobacco stops entering the cut tobacco machine, update the position of the cut tobacco tail every time t, and the updating method is to update the residence position of the cut tobacco in the drum according to step (3).

[0018] Further, the installation attribute parameters of the cut tobacco machine in step S1 include the installation inclination angle a of the drum, the diameter D of the drum, the length L of the drum, and the width w of the radial baffle.

[0019] Further, a plurality of axial baffles are uniformly arranged in the drum of the cut tobacco machine.

[0020] Further, the length t of the single cycle residence time in step S2 is calculated in the following manner:

[0021] t=t r +t f +t b ,

[0022] wherein t r represents the lifting time, t f represents the falling time, t b represents the bottom rolling time.

[0023] Further, in step S2, when the tobacco is lifted to a certain angle, the tobacco reaches a critical balance of force and slides off the baffle, and the angle is The specific calculation method is as follows:

[0024]

[0025] wherein n represents the rotating speed of the drum, unit: round / min, g represents the gravity acceleration, and mu represents the friction coefficient.

[0026] Further, at the angle, the tobacco slides down under the action of gravity, and when sliding, the tobacco slides along the baffle in the first half, and the initial speed along the baffle direction is 0, so that the calculation method of t1 is as follows:

[0027]

[0028] The second half is free fall t2, and the part has an initial speed and is affected by the gravity acceleration, and the formula of calculating the total displacement size by using the initial speed and acceleration and time is as follows: vt+at 2 d, and the specific parameters are brought into to obtain the free fall time.

[0029]

[0030] Therefore,

[0031] t f =t1+t2,

[0032] The lifting time part refers to the time of rotating the tobacco from the vertical direction to The tobacco is always supported by the baffle and rotates along the drum in this time, so that

[0033]

[0034] The bottom rolling time refers to the time of the tobacco staying at the bottom of the drum without being pushed by the baffle, and the tobacco stays at the bottom of the drum in this time, and the time is

[0035] wherein N represents the number of baffles.

[0036] The present application has the following beneficial effects:

[0037] The present application provides a tobacco position state estimation method in a cut tobacco drying machine, which comprises the following steps: BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 It is a schematic diagram of the installation position of the drum of the cut tobacco drying machine.

[0039] Figure 2 It is a schematic diagram of the cross section of the drum.

[0040] Figure 3 It is a prediction result diagram of the tobacco position after the cut tobacco drying machine is started and the tobacco is detected to enter the cut tobacco drying machine.

[0041] Figure 4 It is a speed curve diagram in which the speed gradually increases from 0 to a stable state in the initial stage of the tobacco entering the drum of the cut tobacco drying machine, and the movement on the y-axis presents the characteristics of being slow first and then gradually stable.

[0042] BRIEF DESCRIPTION OF DRAWINGS

[0043] 1, drum; 2, baffle. DETAILED DESCRIPTION

[0044] The technical solutions of the present application will be described in detail below in combination with the drawings. The following examples are only exemplary and can only be used to explain and illustrate the technical solutions of the present application, but cannot be interpreted as a limitation of the technical solutions of the present application.

[0045] The present application provides a tobacco position state estimation method in a cut tobacco drying machine, which comprises the following steps:

[0046] S1, obtain the installation attribute parameters of the cut tobacco drying machine equipment, including the installation inclination angle a of the drum, the diameter D of the drum, the length L of the drum, and the width w of the baffle in the radial direction; the installation position of the drum and the cross section inside the drum are as shown in Figure 1 and Figure 2 The baffle is used for temporarily storing tobacco, and when the drum slowly rotates (for example, clockwise), the tobacco in the baffle near the top falls under the action of gravity.

[0047] In this embodiment, the installation inclination angle a of the drum 1 is 3°, the diameter D of the drum is 1 m, the length L of the drum is 6 m, and the width w of the baffle 2 in the radial direction is 0.2 m. In other embodiments of the present application, the installation position and size of the drum can be changed according to actual needs without affecting the implementation of the technical solutions of the present application.

[0048] S2, calculate the single cycle residence time of tobacco in the drum, that is, the time spent by tobacco from the same position of the cross section back to the position.

[0049] In principle, after the drum rotates about half a circle, the tobacco is affected by gravity and falls from the baffle (approximately free fall), and then is blown to the direction of the drum outlet during the falling process. After advancing a distance, it falls to the bottom of the drum again, and the time length t of this cycle is calculated as follows:

[0050] t=t r +t f +t b ,

[0051] Where t r represents the lifting time, t f represents the falling time, and t b represents the bottom rolling time.

[0052] Where the tobacco reaches a critical balance of force after being lifted to a certain angle and slides off the baffle, and the angle is The specific calculation method is as follows:

[0053]

[0054] Where n represents the rotation speed of the drum, unit: round / min, g represents the acceleration of gravity, and μ represents the friction coefficient.

[0055] In this embodiment, the rotation speed of the drum is 8 round / min, and the friction coefficient is 1.

[0056] At this angle, the tobacco slides down under the action of gravity. Considering the sliding, the first half slides along the baffle, and the initial speed along the baffle direction is 0, so the calculation method of t1 is as follows:

[0057]

[0058] The second half is free fall t2, which has an initial speed and is affected by the acceleration of gravity. The formula for calculating the total displacement size using the initial speed and acceleration and time is: vt+at 2 =d, and the specific parameters are brought in to obtain the time of free fall.

[0059]

[0060] Therefore,

[0061] t f =t1+t2,

[0062] The lifting time part refers to the tobacco rotating from directly below The tobacco is continuously supported by the baffles during this period, thus,

[0063]

[0064] The bottom rolling time refers to the time when the tobacco is at the bottom of the drum and is not pushed by the baffles. During this period, the tobacco stays at the bottom of the drum, and the time is:

[0065]

[0066] where N represents the number of baffles.

[0067] In this embodiment, the number of baffles N = 10. The calculated residence time of a single cycle is t = 2.2882 seconds.

[0068] S3, calculate the residence position of the tobacco in the drum.

[0069] During the residence time of a single cycle, the distance of the tobacco advancing towards the outlet of the drum includes two parts, one part is the displacement of the tobacco caused by the hot air blowing in the single cycle, and the other part is the displacement of the tobacco caused by the gravity component in the free-falling part. The total distance calculation relationship is:

[0070]

[0071] where y k-1 represents the position of the tobacco at the previous moment, y k represents the position of the tobacco at the current moment, is the displacement caused by the gravity component, is the displacement caused by the hot air blowing, where p V represents the medium density of the hot air, B represents the projection area of the tobacco particles in the direction perpendicular to the medium velocity, C represents the drag coefficient, v w represents the wind speed of the hot air, and m c represents the typical mass of the tobacco particles.

[0072] The derivation formula of the speed at the current moment is:

[0073]

[0074] The meanings of the parameters in the above formula are the same as those in the previous text.

[0075] In this embodiment, the projection area of the tobacco particles in the direction perpendicular to the medium velocity B = 3 x 10 -6 m 2 , the drag coefficient C = 0.4, the medium density of the hot air p V = 1 kg / m 3 , and the wind speed v w= 0.1 m / s, typical mass of tobacco particles m c = 1.6 x 10 -6 kg,

[0076] Calculated:

[0077] y k = y k-1 + 0.0696 + 1.8634 * (0.1 - v k-1 ) 2 ,

[0078] v k = v k-1 + 0.8581 * (0.1 - v k-1 ) 2 .

[0079] S4, after the start of the cut tobacco drying machine and detection of the cut tobacco entering the cut tobacco drying machine, the position of the head of the cut tobacco is updated every time t, the updating method is step (3), specifically, the initial position y0=0, v0=0, every t=2.2882, the current speed and the position of the cut tobacco are updated, until y k >L.

[0080] S5, after the cut tobacco drying machine detects that the cut tobacco stops entering the cut tobacco drying machine, the position of the tail of the cut tobacco is updated every time t, the updating method is step (3), specifically, the initial position y0=0, v0=0, every t=2.2882, the current speed and the position of the cut tobacco are updated, until y k >L.

[0081] Figure 3 Fig. 1 is a schematic diagram of the prediction result of the position of the cut tobacco after the start of the cut tobacco drying machine and detection of the cut tobacco entering the cut tobacco drying machine, Figure 4 Fig. 2 is a speed curve diagram, which shows that the speed gradually accelerates from 0 to a stable state in the initial stage of the cut tobacco entering the cut tobacco drying machine roller, so the movement on the y-axis presents the characteristics of slow first and gradually stable.

[0082] The present application can have various changes and variations for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for estimating the position and state of tobacco shreds inside a tobacco drying machine, characterized in that, Includes the following steps: S1. Obtain the installation attribute parameters of the wire drying machine; S2. Calculate the single-cycle residence time of the tobacco in the drum, that is, the time it takes for the tobacco to return from the same position on the cross-section to that position; S3. Calculate the position of the tobacco shreds in the drum. During a single cycle, the distance the tobacco shreds travel towards the drum outlet includes two parts: one part is the displacement caused by the hot air blowing during the single cycle, and the other part is the displacement caused by the gravitational force on the part of the tobacco shreds falling freely. The total displacement is calculated as follows: , in This indicates the position of the tobacco at the previous moment. This indicates the current position of the tobacco. The displacement is caused by the component of gravity. The displacement is caused by the hot air blowing, among which The density of the medium representing hot air. This represents the projected area of ​​tobacco particles in the direction perpendicular to the velocity of the medium. Indicates the drag coefficient. Indicates the wind speed of hot air. Indicates the typical mass of tobacco particles; The derivation formula for the velocity at the current moment is: , The meanings of the parameters in the above formula are the same as those in the previous text; S4. After the tobacco drying machine is turned on and the tobacco shreds are detected to enter the drying machine, the position of the tobacco head is updated every time t. The update method is to update the position of the tobacco shreds in the drum according to step (3). S5. After the tobacco shreds are detected to have stopped entering the drying machine, the position of the tail of the tobacco shreds is updated every time t. The update method is to update the position of the tobacco shreds in the drum according to step (3). Multiple axial baffles are evenly arranged inside the drum of the wire drying machine; The length of the single-cycle dwell time in step S2 The calculation method is as follows: ， in Indicates the lifting time. Indicates the time of descent. Indicates the bottom scrolling time; In step S2, when the tobacco is raised to a certain angle, it reaches a critical equilibrium under force and slides off the baffle. This angle is... The specific calculation method is as follows: ， in, Indicates the rotational speed of the drum, in units of , Represents gravitational acceleration. Indicates the coefficient of friction; The installation attribute parameters of the wire drying machine in step S1 include the roller installation tilt angle α, roller diameter D, roller length L, and the radial width of the baffle w.

2. The method for estimating the position and state of tobacco shreds in a tobacco drying machine according to claim 1, characterized in that, At this angle, the tobacco shreds slide downwards under the influence of gravity. Considering the sliding motion, the first half slides along the baffle, with an initial velocity of 0 along the baffle direction. The calculation method is as follows: ， The latter half is free fall. This part has an initial velocity and is affected by gravitational acceleration. The formula for calculating the overall displacement is used, taking the initial velocity, acceleration, and time as follows: Substituting the specific parameters, we obtain the time of free fall. ， therefore, ， The lifting time refers to the time it takes for the tobacco to rotate from directly below to... During this time, the tobacco shreds rotate along the roller under the support of the baffle, therefore, ， Bottom rolling time refers to the time when the tobacco is at the very bottom of the drum and is not pushed by the baffle. During this time, the tobacco remains at the bottom of the drum. , where N represents the number of baffles.

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