A transfer station blockage early warning method and early warning system

Abstract

This invention provides a method for early warning of material blockage at a transfer station, comprising: obtaining the volumetric flow rate P of the material at the entrance of the transfer station within a statistical time period T. in and the volumetric flow rate P of the material at the transfer station outlet out The difference in material volumetric flow rate dP between the inlet and outlet is obtained; based on the difference in material volumetric flow rate dP, the allowable cross-sectional area S of material to pass through when a blockage occurs in the transfer station is estimated. k Based on the material volumetric flow rate P measured m times in The average value and the cross-sectional area S predicted m times k Permissible material volumetric flow rate P 估 The average value is used to determine whether the transfer station needs to perform a blockage clearing warning. This invention also provides an early warning system using the aforementioned warning method. This invention can dynamically estimate the cross-sectional area S. k The changes in these parameters allow for accurate prediction of the degree of material blockage at transfer stations.

Description

Technical Field

[0001] This invention relates to the field of material conveying technology, specifically to a method and system for early warning of material blockage at a transfer station. Background Technology

[0002] Existing technologies for detecting material blockages at transfer stations include mechanical sampling and visual recognition. Mechanical sampling uses the collision of blocked material with the mechanical structure to generate an alarm and prompt the transfer station to be cleared. Visual recognition, on the other hand, generates an alarm by recognizing images when a blockage occurs.

[0003] Current methods cannot predict material blockages. Alarms are typically triggered only after blockages have occurred or reached a certain level. At this point, clearing the blockage is time-consuming, and the transfer station's capacity has already decreased by the time the blockage begins, even before the alarm threshold is reached. Therefore, the transfer station's capacity gradually declines between the onset of the blockage and the alarm, severely impacting its overall capacity. If blockages could be predicted in advance, they could be cleared promptly when their impact on transfer capacity is not yet severe. This would reduce clearing time and ensure that the transfer station operates at a high capacity most of the time.

[0004] In summary, there is an urgent need for a method and system for early warning of material blockage at transfer stations to solve the problems existing in the current technology. Summary of the Invention

[0005] The purpose of this invention is to provide a method for early warning of material blockage at transfer stations, aiming to solve the problem that existing methods for detecting material blockage cannot predict it. The specific technical solution is as follows:

[0006] A method for early warning of material blockage at a transfer station includes:

[0007] Obtain the volumetric flow rate P of the material at the entrance of the transfer station within the statistical time period T. in and the volumetric flow rate P of the material at the transfer station outlet out And obtain the difference dP between the material volume flow rate at the inlet and outlet;

[0008] Based on the difference in material volumetric flow rate dP, estimate the allowable cross-sectional area S of material to pass through when a blockage occurs in the transfer station. k ;

[0009] Based on the material volumetric flow rate P measured m times in The average value and the cross-sectional area S predicted m times k Permissible material volumetric flow rate P 估 The average value is used to determine whether the transfer station needs to issue a blockage clearing warning, where m is a natural number greater than or equal to 1.

[0010] The preferred technical solution above uses formula (15) to estimate the allowable cross-sectional area S of material passing through the transfer station when a blockage occurs. k :

[0011]

[0012] Where: S is the flow cross section of the transfer station, θ is the angle between the slope formed by the accumulation of materials in the transfer station and the horizontal plane, and π is pi.

[0013] Among the above technical solutions, there are two preferred methods for determining the value of θ:

[0014] The first method is to take multiple measurements when blockage occurs and then select the average value.

[0015] The second method is to directly select the angle of repose of the material stacking.

[0016] The preferred technical solution above is obtained by formula (16) for the cross-sectional area S. k Permissible material volumetric flow rate P 估 :

[0017] P 估 =S k ×v 截 (16),

[0018] Where: v 截 For the material to pass through the cross-sectional area S k The speed.

[0019] The preferred technical solution among the above is v 截 It can be obtained directly through measurement or according to formula (17):

[0020]

[0021] Where: H1 is the height from the unloading point to the transfer station exit, and g is the acceleration due to gravity.

[0022] The preferred technical solution among the above is:

[0023] When the material volumetric flow rate P is measured m times in The average value is greater than the cross-sectional area S estimated in m trials. k Permissible material volumetric flow rate P 估 When the average value is reached, a transfer station cleaning warning will be issued:

[0024]

[0025] in, This represents the volumetric flow rate of the material at the inlet of the transfer station during the j-th measurement. This represents the estimated cross-sectional area within the transfer station that allows material to pass through during the j-th measurement. This represents the cross-sectional area through which the material passes during the j-th measurement. The speed.

[0026] The present invention also provides a material blockage early warning system for transfer stations. The early warning system uses the aforementioned material blockage early warning method to determine whether to issue an early warning. When an early warning is issued, an alarm is used to prompt staff and / or control a cleaning device to clear the material blockage at the transfer station.

[0027] In a preferred embodiment of the above technical solutions, the cleaning device includes a drive device, a transmission shaft, and a scraper. The scraper is symmetrically arranged at the lower end of the transmission shaft, and the upper end of the transmission shaft is connected to the drive device. After receiving a cleaning signal, the drive device drives the transmission shaft and the scraper to rotate together.

[0028] In the preferred embodiment of the above technical solutions, the scraper is mounted on the drive shaft via a scraper bracket.

[0029] In the preferred embodiment of the above technical solutions, both the scraper rake and the scraper rake support are made of steel bars with a rhomboid cross-section, wherein the long axis of the rhombus is set along the vertical direction.

[0030] The application of the technical solution of the present invention has the following beneficial effects:

[0031] This invention can determine the material volumetric flow rate P at the entrance of the transfer station. in and the volumetric flow rate P of the material at the transfer station outlet out The difference dP is used to estimate the cross-sectional area S that allows material to pass through when there is blockage inside the transfer station. k This invention allows for the dynamic estimation of the cross-sectional area S, based on the assessment of the impact of materials accumulating in the transfer station on its operational capacity. k The changes in the volumetric flow rate P are used to accurately predict the degree of material blockage in the transfer station. in The average value and the m-th material volumetric flow rate P 估 Using the average value for early warning judgment can prevent false alarms caused by single prediction errors and ensure the accuracy of early warnings; this invention uses real-time detection of the difference dP and the estimated cross-sectional area S k It can issue an early warning when the transfer capacity of the transfer station begins to decline, ensuring that the transfer station can maintain a high transfer capacity most of the time.

[0032] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0033] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0034] Figure 1 This is a schematic diagram showing the layout of the feed conveyor belt, transfer station, and discharge conveyor belt;

[0035] Figure 2 This is a schematic diagram of the cross-section of the conveyor belt carrying material;

[0036] Figure 3 This is an auxiliary schematic diagram illustrating the allowable material flow cross-section when calculating material blockage at a transfer station;

[0037] Figure 4 This is a schematic diagram of the cleaning device;

[0038] Among them, 1. Feed belt conveyor, 2. Transfer station, 3. Discharge belt conveyor, 4. Drive unit, 5. Drive shaft, 6. Scraper rake, 7. Scraper rake bracket; 01. 2D laser scanning device, 02. Mounting bracket, 03. Material, 04. Belt, 05. Idler roller, 06. Belt bracket. Detailed Implementation

[0039] To facilitate understanding of the present invention, a more complete description is provided below, along with preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0041] Example:

[0042] See Figures 1-3 This embodiment provides a method for early warning of material blockage at a transfer station, including the following steps:

[0043] First, obtain the material volumetric flow rate P at the entrance of the transfer station within the statistical time period T. in and the volumetric flow rate P of the material at the transfer station outlet out And obtain the difference dP between the material volume flow rate at the inlet and outlet;

[0044] like Figure 1As shown, material 03 is fed into the inlet of the transfer station 2 via the infeed conveyor belt 1, and material 03 is transported out of the transfer station via the discharge conveyor belt 3. Therefore, by performing detection on the infeed conveyor belt 1 and the discharge conveyor belt 3 respectively, the material volumetric flow rate P can be obtained. in and material volumetric flow rate P out .

[0045] Belt conveyors, short for belt conveyors, are available in stationary and mobile types. They are simple in structure, highly efficient, and continuous conveying machines that use a flexible conveyor belt as the material-carrying and traction component. An endless conveyor belt wraps around a drive drum and a redirecting drum, with upper and lower branches between the two drums supported by several idlers. Material is placed on the upper branch, and the friction between the drive drum and the belt pulls the conveyor belt and the material. Belt conveyors are suitable for conveying bulk materials and packaged goods horizontally and at an incline, and can also be used in assembly lines for certain processes. They are simple in structure, operate smoothly and reliably, are highly adaptable to materials, have a large conveying capacity, low power consumption, and are widely used.

[0046] In this embodiment, to obtain the material volumetric flow rate, flow detection devices are installed on both the infeed conveyor belt 1 and the discharge conveyor belt 3. For example... Figure 2 As shown, the flow detection device includes a 2D laser scanning device 01 (which can also be replaced by a line structured light scanner). The 2D laser scanning device 01 is installed directly above the belt via a mounting bracket 02. The mounting bracket 02 is set on the belt support 06. The installation height can be adjusted according to the site environment, ranging from 1 meter to 4 meters. As the belt moves, the 2D laser scanning device scans the material 03 on the belt 04.

[0047] A two-dimensional coordinate system is established using a 2D laser scanning device. The X and Y directions and positions of the coordinate system are as follows: Figure 2 As shown, the center of the coordinate system is located at the optical center of the 2D laser scanning device. The 2D laser scanning device can obtain data from n points by acquiring data from one cross section at a time, including the distances from the n measured points to the 2D laser scanning device and the measurement angle of each point. Based on the angle and distance information of each measurement point, it can be converted into two-dimensional points in the X and Y coordinate system. These two-dimensional points constitute the surface contour of the material on the conveyor belt. Figure 2 In this context, H represents the maximum distance from the scanner (i.e., the 2D laser scanning device) to the upper surface of the belt, and L represents the width of the belt.

[0048] A 2D laser scanning device generates n distance and corresponding angle data from the scanner to n measurement points during a single measurement, where the k-th data point is point P. k The angle it measures is θ k The measured distance value is d k Then its corresponding X and Y coordinate values ​​P k-x Pk-y They are respectively:

[0049] P k-x =d k *cos(θ k (1),

[0050] P k-y =d k *sin(θ k (2) Based on the measured n discrete data points, a B-spline interpolation curve can be fitted, and its equation is:

[0051]

[0052] Where: N k,p (t) is a p-th degree B-spline basis function, usually p = 2, t = [0, 1]; x k For discrete data point P k The x-axis coordinate value, y k For discrete data point P k The Y-axis coordinate value.

[0053] For each input variable x, a corresponding t can be obtained using formula (3), and then the corresponding y value can be calculated using t. This can be described as: y = B(x) = g(f -1 (x)).

[0054] Because of the presence of roller 05 on belt support 06, the belt at the measurement position is not deformed. The belt's function is h(x), which is a high-order curve. It could be the lower half of an ellipse, a parabola, or a piecewise parabola. Therefore, assuming the belt's equation is a cubic curve, then:

[0055] h(x) = a*x 3 +b*x 2 +c*x+d (4),

[0056] In actual measurement, the outline coordinates of the belt without material can be measured by a laser scanner. The coefficients of the equation can be obtained by substituting the coordinates of the belt location into equation (4).

[0057] Based on the calculated data contour equation, the cross-sectional area of ​​the material can be calculated. Therefore, the cross-sectional area of ​​the material on the belt is calculated as follows:

[0058]

[0059] in: The step size in the X direction is...

[0060] Based on the cross-sectional area obtained from formula (5) and the belt speed, the volumetric flow rate of the material on the belt can be calculated. Given the belt speed v and the data measurement frequency f, and since the cross-sectional area is a discrete variable, the distance the belt travels per unit time dt is l.

[0061] l=v*dt / f (6), then the volumetric flow rate of the material on the belt per unit time can be calculated by accumulation:

[0062]

[0063] Wherein: S i Let be the cross-sectional area of ​​the material detected in the i-th instance.

[0064] At this point, the material volumetric flow rate P at the inlet within the statistical time T can be obtained. in :

[0065]

[0066] Similarly, the material volumetric flow rate P at the outlet can be calculated. out ;

[0067] The difference in material volumetric flow rate at the inlet and outlet, dP, is:

[0068] dP = P in -P out (9).

[0069] Then, based on the difference in material volumetric flow rate dP, the allowable cross-sectional area S of material to pass through when a blockage occurs in the transfer station is estimated. k Then, based on the material volumetric flow rate P measured m times... in The average value and the cross-sectional area S predicted m times k Permissible material volumetric flow rate P 估 The average value is used to determine whether the transfer station needs to issue a blockage clearing warning, where m is a natural number greater than or equal to 1;

[0070] Specifically, since the blockage starts from the bottom of the transfer station, for a cylindrical transfer station, the blockage will first form an inverted frustum inside the station, and then eventually an inverted cone. When the inverted frustum forms, the transfer station has begun to blockage, but is not completely blocked. When the inverted cone forms, it indicates that the transfer station is completely blocked. Therefore, the transfer station needs to be cleaned during the process of the inverted frustum transforming into an inverted cone. When an inverted frustum forms inside the transfer station, the flow cross-sectional area S at the bottom of the inverted frustum can be estimated based on the difference in material volume flow rate dP. k Please see Figure 3 Here, the estimated cross-sectional area S in this embodiment is... k Please provide an explanation.

[0071] like Figure 3 As shown, an auxiliary line is established on the already formed inverted frustum to form an inverted cone, where h1 is the height of the inverted cone, h2 is the height of the cylinder formed by the auxiliary line, r1 is the inner diameter of the transfer station, r2 is the radius of the flow section formed by the accumulated material (i.e., the blockage), and S k Let S be the area of ​​the flow cross section that allows material to pass through when a blockage occurs, S be the flow cross section of the transfer station, and θ be the angle between the slope formed by the accumulation of material in the transfer station and the horizontal plane. θ can be selected based on experience, for example, by taking multiple measurements when a blockage occurs and then selecting the average value. Alternatively, θ can be directly selected as the angle of repose of the material accumulation.

[0072] Based on the triangular relationship, we can obtain:

[0073]

[0074]

[0075] The accumulation volume V of the material in the transfer station can be obtained according to formulas (12)-(14). l Expressed as:

[0076]

[0077]

[0078]

[0079] Due to the accumulation volume V of the material in the transfer station l This is the difference in material volumetric flow rate, dP. Therefore, we can obtain:

[0080]

[0081] Where π is the ratio of a circle's diameter to its circumference.

[0082] After obtaining the difference between the volumetric flow rate and the material volume flow rate dP, the allowable cross-sectional area S of the material to pass through when there is a blockage in the transfer station can be obtained according to formula (15). k ; Combining materials through cross-sectional area S k speed v 截 The volumetric flow rate P of the material passing through the cross-section during a single measurement can be obtained. 估 As shown in formula (16):

[0083] P 估 =S k ×v 截 (16),

[0084] Among them, v 截It can be obtained directly by sensor measurement, or it can be estimated according to formula (17):

[0085]

[0086] In the formula: H1 is the height from the feed conveyor to the transfer station outlet (the material enters the transfer station vertically from the feed point and leaves the transfer station from the outlet, and the material is in free fall during this process), g is the acceleration due to gravity; since the material blockage in the transfer station starts from the bottom and the material is in free fall, the formula (17) can be used to estimate the actual needs.

[0087] Furthermore, in this embodiment, when the material volumetric flow rate P is measured m times... in The average value is greater than the estimated cross-sectional area S of m times. k Permissible material volumetric flow rate P 估 When the average value is reached, a transfer station cleaning warning will be issued:

[0088]

[0089] in, This represents the volumetric flow rate of the material at the inlet of the transfer station during the j-th measurement. This represents the estimated cross-sectional area within the transfer station that allows material to pass through during the j-th measurement. This represents the cross-sectional area through which the material passes during the j-th measurement. The speed, of which It can be estimated according to formula (17) or obtained by sensor measurement.

[0090] The material blockage early warning method for the transfer station in this embodiment is built into the early warning system. When the early warning system determines that the transfer station needs to be cleaned according to the early warning method, it can remind the operators by means of an alarm (such as an audible or visual alarm). At the same time, the early warning system can also control the cleaning device to clean the transfer station. For the composition of the early warning system, please refer to the prior art. It will not be described in detail in this embodiment.

[0091] See Figure 4 This embodiment also provides a cleaning device for a transfer station. The cleaning device includes a drive device 4, a transmission shaft 5, and a scraper 6. The scraper 6 is symmetrically arranged at the lower end of the transmission shaft 5, and the upper end of the transmission shaft 5 is connected to the drive device 4. The drive device 4 drives the transmission shaft 5 and the scraper 6 to rotate together. Preferably, the scraper 6 is mounted on the transmission shaft 5 via a scraper bracket 7. The drive device is either an electric motor or a hydraulic motor.

[0092] More preferably, both the scraper rake 6 and the scraper rake support 7 are made of steel bars with a rhomboid cross-section, wherein the long axis of the rhombus is set in the vertical direction, so as to reduce the impact of falling material on the scraper rake support and scraper rake and the accumulation of material.

[0093] The rake-type structure minimizes contact with the material when scraping the stockpile, reducing the power required for rotation. Meanwhile, the symmetrically arranged scraper rakes in the transfer station can clean a ring of sticky material with just half a rotation.

[0094] The early warning system and the cleaning device can communicate. When the early warning system determines, using the judgment method described in this embodiment, that the transfer station needs to be cleared of blockages, it sends a cleaning signal to control the cleaning device to perform the cleaning action. Of course, Figure 4 The cleaning device shown is only one method provided in this embodiment. When it is determined that the transfer station needs to be cleaned, those skilled in the art may also use other means to clean the transfer station.

[0095] The method in this embodiment can be based on the material volumetric flow rate P at the entrance of the transfer station. in and the volumetric flow rate P of the material at the outlet of the transfer station out The difference dP is used to estimate the cross-sectional area S that allows material to pass through when there is blockage inside the transfer station. k This allows for the assessment of the impact of materials accumulating in the transfer station on its operational capacity, and enables dynamic estimation of the cross-sectional area S. k The changes in the volumetric flow rate P are used to accurately predict the degree of material blockage in the transfer station. in The average value and the m-th material volumetric flow rate P 估 Using the average value for early warning judgment can prevent false early warnings caused by single prediction errors and ensure the accuracy of early warnings; the method in this embodiment detects the difference dP and the estimated cross-sectional area S in real time. k It can issue an early warning when the transfer capacity of the transfer station begins to decline, ensuring that the transfer station can maintain a high transfer capacity most of the time.

[0096] By controlling the cleaning device through an early warning system, the cleaning process can be automated, reducing the probability of blockage failures at the transfer station. At the same time, the cleaning device has a simple structure, low maintenance costs, and is stable and reliable.

[0097] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for early warning of material blockage at a transfer station, characterized in that, include: Obtain the volumetric flow rate of materials at the entrance of the transfer station within the statistical time period T. Material volume flow rate at the transfer station exit And obtain the difference in material volumetric flow rate between the inlet and outlet. ; Based on the difference in material volumetric flow rate Estimate the cross-sectional area of ​​material that can pass through when a blockage occurs in the transfer station. ; according to m The volumetric flow rate of the material measured in this instance. The average value and m The estimated cross-sectional area Permissible material volumetric flow rate The average value is used to determine whether the transfer station needs to issue a blockage clearing warning. m It is a natural number greater than or equal to 1; Based on formula (15), estimate the cross-sectional area of ​​material that can pass through when a blockage occurs in the transfer station. : dP （15）， in: This refers to the cross-sectional area for the transfer station's circulation. It is the angle between the slope formed by the accumulation of materials within the transfer station and the horizontal plane. Pi; when m The volumetric flow rate of the material measured in this instance. The average value is greater than m The estimated cross-sectional area Permissible material volumetric flow rate When the average value is reached, a transfer station cleaning warning will be issued: （18）， in, Indicates the first j The volumetric flow rate of the material at the entrance of the transfer station was measured during this second measurement. Indicates the first j The estimated cross-sectional area within the transfer station that allows materials to pass through during this measurement. Indicates the first j During the second measurement, the material passed through the cross-sectional area The speed.

2. The method for early warning of material blockage at a transfer station according to claim 1, characterized in that, There are two methods to determine the value of : The first method is to take multiple measurements when blockage occurs and then select the average value. The second method is to directly select the angle of repose of the material stacking.

3. The method for early warning of material blockage at a transfer station according to claim 1, characterized in that, The cross-sectional area is obtained according to formula (16). Permissible material volumetric flow rate : （16）， in: For material passing through cross-sectional area The speed.

4. The method for early warning of material blockage at a transfer station according to claim 3, characterized in that, It can be obtained directly through measurement or according to formula (17): （17）， in: This refers to the height from the material unloading point to the exit of the transfer station. g This is the acceleration due to gravity.

5. A material blockage early warning system for a transfer station, characterized in that, The early warning system uses the material blockage early warning method for transfer stations as described in any one of claims 1-4 to determine whether to issue an early warning; when an early warning is issued, the system prompts staff and / or controls the cleaning device to clear the material blockage at the transfer station via an alarm.

6. The material blockage early warning system for transfer stations according to claim 5, characterized in that, The cleaning device includes a drive unit (4), a transmission shaft (5) and a scraper (6). The scraper (6) is symmetrically arranged at the lower end of the transmission shaft (5). The upper end of the transmission shaft (5) is connected to the drive unit (4). After receiving the cleaning signal, the drive unit (4) drives the transmission shaft (5) and the scraper (6) to rotate together.

7. The material blockage early warning system for transfer stations according to claim 6, characterized in that, The scraper (6) is mounted on the drive shaft (5) via a scraper bracket (7).

8. The material blockage early warning system for transfer stations according to claim 7, characterized in that, Both the scraper rake (6) and the scraper rake support (7) are made of steel bars with a rhomboid cross section, wherein the long axis of the rhomboid is set in the vertical direction.

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