A plastic protective tube production extrusion device

Abstract

The present invention relates to the field of injection molding technology, and specifically to a plastic protective tube production extrusion device. A material stirring area and a material extrusion area are set up in different areas, and the flow rate and temperature of the material stirring and extrusion areas are monitored. Combined with historical data analysis, the ideal flow rate and temperature range when the materials are evenly mixed are established. During the production process, the flow rate and temperature values ​​of the material stirring area are monitored in real time, and the motor speed of the material extrusion area is dynamically adjusted, thereby regulating the extrusion speed of the material extrusion area to ensure that the material extrusion speed is accurately matched with the stirring and mixing state. This instant feedback and adjustment mechanism significantly enhances the stability and controllability of the production rate and product quality.

Description

Technical Field

[0001] The invention relates to the technical field of injection molding, and in particular to a production extrusion device for a plastic protection tube. Background Art

[0002] With the increasing demand for industrial automation and cable protection, the market demand for plastic protective tubes (such as cable ducts and cable protection tubes) continues to grow. These tubes are widely used in industries such as construction, electricity, communications, and automobiles to protect cables and pipes from physical damage, chemical corrosion, and environmental impacts. In the production process of plastic protective tubes, uniform mixing and precise extrusion of materials are key factors to ensure product quality and production efficiency.

[0003] Existing plastic protective tube production extrusion devices usually use a fixed motor speed to control the extrusion speed of the material when extruding the mixed material. However, since the degree of material mixing uniformity will change dynamically at different times, using a fixed motor speed to control the extrusion speed may lead to inaccurate judgment of the material uniformity, thereby affecting the production rate and product quality of the plastic protective tube. Summary of the invention

[0004] In order to solve the technical problem that the material extrusion speed cannot be matched with the dynamically changing material uniformity when the material extrusion speed is controlled by a fixed motor speed, thereby affecting the production rate and product quality of the plastic protective tube, the purpose of the present invention is to provide a plastic protective tube production extrusion device, and the technical solution adopted is as follows:

[0005] The present invention proposes a plastic protection tube production extrusion device, the plastic protection tube production extrusion device comprises a heating cylinder, the heating cylinder is divided into a material stirring area and a material extrusion area, a temperature sensor and a flow rate sensor are installed at the central position of the bottom of the material stirring area and the entrance position of the material extrusion area, the temperature sensor is used to obtain the temperature time series data when the material is stirred, and the flow rate sensor is used to obtain the flow rate time series data when the material is stirred; a motor for driving a rotating shaft in the material extrusion area is installed in the material extrusion area, and the motor is also provided with a motor control module, and the motor control module is used to control the speed of the motor according to the temperature time series data and the flow rate time series data of the material, wherein the motor speed control method comprises:

[0006] Obtaining flow rate time series data and temperature time series data of materials at two locations within a preset number of historical periods;

[0007] In all historical cycles, the numerical characteristics and differences between the flow rate time series data of the materials at two locations are integrated to determine the normal flow rate range for uniform material mixing;

[0008] In each historical cycle, the data values ​​in the flow rate time series data of each location are screened based on the normal flow rate range to determine the target time; in all historical cycles, the numerical characteristics of the temperature time series data of the two locations at the target time are integrated to determine the normal temperature range for uniform material mixing;

[0009] Based on the deviation between the flow velocity value at the central position at the current moment and the flow velocity value in the normal flow velocity range, as well as the deviation between the temperature value at the central position at the current moment and the temperature value in the normal temperature range, the motor speed of the rotating shaft in the material extrusion area is adjusted to determine the motor speed at the next moment.

[0010] Furthermore, the method for obtaining the normal flow rate interval includes:

[0011] The central position at the bottom of the material stirring area is used as the first marking position, and the entrance position of the material extrusion area is used as the second marking position;

[0012] In each historical period, based on the numerical characteristics of the flow velocity value in the flow velocity time series data at the second marking position, a flow velocity standard value and a reference time are determined;

[0013] In each historical cycle, in the flow velocity time series data at the first mark position, the moment at the same position as the reference moment in the flow velocity time series data at the second mark position is used as the comparison moment; based on the difference between the flow velocity value at the comparison moment and the flow velocity standard value, the flow velocity value at the comparison moment is adjusted to determine the flow velocity boundary value;

[0014] In each historical period, a normal flow rate range is determined based on the flow rate standard value and the flow rate boundary value;

[0015] The intersection of the normal flow rate ranges of all historical cycles is taken as the normal flow rate range for uniform material mixing.

[0016] Furthermore, in each historical period, based on the numerical characteristics of the flow rate value in the flow rate time series data at the second mark position, determining the flow rate standard value and the reference time includes:

[0017] In each historical period, the mode of all flow velocity values ​​in the flow velocity time series data at the second mark position is used as the flow velocity standard value, and the time corresponding to all flow velocity standard values ​​is used as the reference time.

[0018] Furthermore, the method for obtaining the flow velocity boundary value includes:

[0019] The absolute value of the difference between the flow velocity value at each comparison moment and the standard flow velocity value is taken as a flow velocity difference factor; among all the flow velocity difference factors, the occurrence probability of each flow velocity difference factor is calculated;

[0020] The velocity values ​​at the comparison moments corresponding to the velocity difference factors are weightedly fused using the occurrence probabilities of all velocity difference factors to obtain the velocity boundary value.

[0021] Furthermore, the method for obtaining the target time includes:

[0022] In each historical cycle, in the two flow velocity time series data, traversal starts from the first moment. When the flow velocity values ​​corresponding to the moments at the same position in the two flow velocity time series data exist in the normal flow velocity range at the same time, the currently traversed moment in the two flow velocity time series data is used as the target moment in each historical cycle.

[0023] Furthermore, the method for obtaining the normal temperature range includes:

[0024] In each historical period, the normal temperature range is determined based on the numerical characteristics of the temperature values ​​at the target time in the two temperature time series data;

[0025] The intersection of the normal temperature ranges of all historical cycles is taken as the normal temperature range for uniform material mixing.

[0026] Furthermore, the method for obtaining the normal temperature range includes:

[0027] In the temperature time series data at each position in each historical period, the average of the temperature values ​​corresponding to the target time is used as the temperature boundary value corresponding to each position, and the normal temperature range is determined based on the temperature boundary values ​​at the two positions.

[0028] Furthermore, the method for obtaining the motor speed at the next moment includes:

[0029] Based on the deviation between the flow velocity value at the central position at the current moment and the flow velocity value within the normal flow velocity interval, a normal flow velocity difference factor is determined;

[0030] Determine the normal temperature difference factor based on the deviation between the temperature value at the central position at the current moment and the temperature value in the normal temperature range;

[0031] The normalized value of the sum of the flow rate normal difference factor and the temperature normal difference factor is used as an adjustment weight, and the product of the adjustment weight and the preset adjustment value is used as a speed adjustment amount;

[0032] The motor speed of the motor of the rotating shaft in the material extrusion area at the current moment is adjusted according to the speed adjustment amount to obtain the motor speed at the next moment, and the motor speed at the current moment is positively correlated with the motor speed at the next moment, wherein, if the flow velocity value at the central position at the current moment is within the normal flow velocity range, then the speed adjustment amount is positively correlated with the motor speed at the next moment, and if the flow velocity value at the central position at the current moment is not within the normal flow velocity range, then the speed adjustment amount is negatively correlated with the motor speed at the next moment.

[0033] Furthermore, the method for obtaining the normal flow velocity difference factor includes:

[0034] Taking the minimum value of all flow velocity values ​​within the normal flow velocity interval as the flow velocity characteristic value;

[0035] The value obtained by normalizing the absolute value of the difference between the flow velocity value at the central position at the current moment and the flow velocity characteristic value is used as the flow velocity normal difference factor.

[0036] Furthermore, the method for obtaining the normal temperature difference factor includes:

[0037] Taking the minimum value of all temperature values ​​within the normal temperature range as the temperature characteristic value;

[0038] The value obtained by normalizing the absolute value of the difference between the temperature value at the central position at the current moment and the temperature characteristic value is used as the temperature normal difference factor.

[0039] The present invention has the following beneficial effects:

[0040] By dividing the device into a material stirring area and a material extrusion area, and installing temperature sensors and flow rate sensors at key positions in the material stirring area—the bottom center and near the entrance of the material extrusion area, the material stirring process can be fully monitored, so that the motor speed of the rotating shaft in the material extrusion area can be controlled in real time according to the uniformity of the material stirring, thereby ensuring the production rate and product quality of the plastic protective tube. First, the flow rate time series data and temperature time series data at two positions in a preset number of historical cycles are obtained, and rich production data samples can be accumulated. Due to the different mixing states of materials at different positions in the stirring area, when it is closer to the material extrusion area, it is believed that its mixing state will be more uniform and more in line with the production standards. On the contrary, when it is far away from the material extrusion area, that is, at the central position at the bottom of the material stirring area of ​​the device, the mixing uniformity of the material will be weaker; at the same time, the corresponding properties of the material in different mixing states will change, which will lead to corresponding changes in the flow rate and temperature. Therefore, by analyzing the numerical characteristics and differences between the flow rate time series data of the materials at the two positions in all historical cycles, the normal flow rate range for uniform material mixing can be determined, so as to reflect the range of the material flow rate under normal conditions when the materials are uniformly mixed. Next, in view of the different mixing degrees of the materials, the temperature will also change. Therefore, in each historical cycle, the time corresponding to the flow rate value in the flow rate time series data at each position that meets the normal flow rate range is screened out as the target time. The material state at the target time can be regarded as having reached a uniform mixing state at the flow rate analysis level. Then, in all historical cycles, the numerical characteristics of the temperature values ​​in the two temperature time series data at the target time are combined to determine the normal temperature range for uniform material mixing. The normal temperature range reflects the range of the material temperature under normal conditions when the materials are uniformly mixed. Further, the flow rate value and temperature value at the central position at the current moment can be obtained. By comparing the deviation of the flow rate value with the flow rate value in the normal flow rate range and the deviation of the temperature value with the temperature value in the normal temperature range, the motor speed in the material extrusion area is dynamically adjusted, so that the extrusion speed of the material extrusion area at the next moment can match the mixing degree of the material in the material stirring area. This instant response control method can more accurately judge the mixing uniformity of the material, thereby ensuring the production rate and product quality of the plastic protective tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 A schematic diagram of the overall structure of a plastic protective tube production extrusion device provided by one embodiment of the present invention;

[0043] Figure 2 A schematic diagram of the internal structure of a heating cylinder provided by an embodiment of the present invention;

[0044] Figure 3 A schematic structural diagram of a first rotating shaft provided by an embodiment of the present invention;

[0045] Figure 4 A schematic structural diagram of a first rotating shaft provided by an embodiment of the present invention;

[0046] Figure 5 A method flow chart of a motor speed control method provided by an embodiment of the present invention;

[0047] Figure 6 A method flow chart of a method for obtaining a normal flow rate interval provided by an embodiment of the present invention;

[0048] Figure 7 A method flow chart of a method for obtaining a normal temperature range provided by an embodiment of the present invention;

[0049] Figure 8 A method flow chart of a method for obtaining the motor speed at the next moment provided by an embodiment of the present invention;

[0050] Figure markings: 1-mounting plate, 2-heating cylinder, 3-first rotating shaft, 4-first spiral blade, 5-auxiliary branch chain, 6-gear, 7-gear ring, 8-second rotating shaft, 9-second spiral blade, 10-worm gear, 11-worm, 12-first motor, 13-second motor, 14-first sensor group, 15-second sensor group, 16-docking mechanism, 17-cooling mechanism, 18-feeding port, A-material stirring area, B-material extrusion area. DETAILED DESCRIPTION

[0051] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the specific implementation, structure, features and effects of a plastic protective tube production extrusion device proposed by the present invention in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0052] Unless defined otherwise, 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 belongs.

[0053] The specific scheme of the plastic protection tube production extrusion device provided by the present invention is described in detail below with reference to the accompanying drawings.

[0054] See also Figure 1 , which shows a schematic diagram of the overall structure of a plastic protective tube production extrusion device provided by an embodiment of the present invention, including a mounting plate 1, a heating cylinder 2, a first motor 12, a second motor 13, a docking mechanism 16, a cooling mechanism 17 and a feed port 18.

[0055] In the embodiment of the present invention, the interior of the heating cylinder 2 is divided into a material stirring area and a material extrusion area. Figure 2 , which shows a schematic diagram of the internal structure of a heating cylinder provided by an embodiment of the present invention, Figure 3 and Figure 4 The schematic diagrams of the structures of the first rotating shaft and the second rotating shaft provided in one embodiment of the present invention are respectively. The heating cylinder 2 is divided into a material stirring area A and a material extrusion area B. In the material stirring area A, the first motor 12 is used to control the rotation speed of the first rotating shaft 3 in the material stirring area, thereby driving the first spiral blade 4 to stir and mix the material. In the material extrusion area B, the second motor 13 controls the rotation of the worm 11, and then the worm 11 cooperates with the worm gear 10 to control the rotation speed of the second rotating shaft 8, thereby driving the second spiral blade 9 to control the material extrusion speed, wherein a motor control module (not shown in the figure) is arranged in the second motor 13. In order to make the extrusion speed of the material extrusion area B at the next moment match the mixing degree of the material in the material stirring area A, a first sensor group 14 (including a temperature sensor and a flow rate sensor) is arranged at the central position of the bottom of the material stirring area A, and a second sensor group 15 (including a temperature sensor and a flow rate sensor) is arranged at the position closest to the entrance of the material extrusion area B, which is used to obtain the temperature time series data and flow rate time series data when the material is stirred.

[0056] In the embodiment of the present invention, the motor control module can control the speed of the second motor 13 corresponding to the second rotating shaft 8 in the material extrusion area B through the temperature time series data and flow rate time series data at two positions in the material stirring area A. In the subsequent motor speed control method, the motor refers to the second motor 13. Figure 5 , which shows a method flow chart of a motor speed control method provided by an embodiment of the present invention, the method comprising the following steps:

[0057] Step S1: Obtaining flow rate time series data and temperature time series data of materials at two locations within a preset number of historical periods.

[0058] In the production process of plastic protective tubes, uniform mixing and precise extrusion of materials are key factors to ensure product quality and production efficiency. However, existing plastic extrusion devices often rely on a fixed material extrusion speed for operation. This method is difficult to adapt to the dynamic changes in the characteristics of the material during mixing and stirring, and it is easy to cause the material extrusion speed to be too fast or too slow, thus affecting the quality and production efficiency of the final product.

[0059] In an embodiment of the present invention, a plastic protective tube production extrusion device is divided into a material stirring area and a material extrusion area. In the material stirring area, since the material close to the material extrusion area is stirred for a longer time, its mixing uniformity is higher than that far away from the material extrusion area. Under different mixing conditions, the characteristics of the material, such as temperature and flow rate, will change. Therefore, in an embodiment of the present invention, temperature timing data and flow rate timing data are obtained by placing a temperature sensor and a flow rate sensor at the central position at the bottom of the material stirring area and at the position closest to the entrance of the material extrusion area. The motor speed of the material extrusion area is adjusted according to these data, thereby controlling the material extrusion speed.

[0060] During the operation of the plastic protective tube production extrusion device, in order to achieve precise control of the material extrusion process, it is necessary to accumulate rich production data samples. Therefore, based on the temperature sensors and flow rate sensors at two positions, the temperature time series data and flow rate time series data of the materials at two positions within a preset number of historical cycles are obtained.

[0061] It should be noted that the length of the cycle can be expressed in days, and the preset number can be set to 30, that is, the data cycle within one month from the current data cycle is taken, the time interval for data collection in each cycle is set to 1s, the length of each historical cycle must be consistent and sampling is performed simultaneously at two locations; the preset number, cycle length and sampling time interval can be adjusted according to the implementation scenario and are not limited here.

[0062] At this point, the flow rate time series data and temperature time series data of the material at two locations within a preset number of historical periods can be obtained.

[0063] Step S2: In all historical cycles, the numerical characteristics and differences between the flow rate time series data of the materials at the two positions are integrated to determine the normal flow rate range for uniform material mixing.

[0064] Since the mixing state at the bottom center of the material stirring area is less uniform than the mixing state at the position closest to the entrance of the material extrusion area (because the material at the bottom center has a shorter stirring time than the material at the position closest to the entrance of the material extrusion area), there will be certain differences in the numerical characteristics of the flow rate values ​​in the flow rate time series data at the two positions. Therefore, by collecting and analyzing the numerical characteristics and differences in the flow rate time series data of the materials at the two positions in the historical period, the flow rate characteristics of the materials in different mixing states can be identified, which helps to determine the normal flow rate range for uniform material mixing. The normal flow rate range can provide an approximate range of the flow rate when the materials are uniformly mixed. This information is of great significance for the subsequent adjustment of the motor speed in the material extrusion area.

[0065] Preferably, in one embodiment of the present invention, the method for obtaining the normal flow rate interval includes:

[0066] See also Figure 6 , which shows a method flow chart of a method for obtaining a normal flow rate interval in one embodiment of the present invention, the method comprising the following steps:

[0067] Step S201: Determine a first mark position and a second mark position, and in each historical period, determine a flow rate standard value and a reference time based on the numerical characteristics of each flow rate value in the flow rate time series data of the second mark position.

[0068] In the embodiment of the present invention, for the convenience of subsequent description, the central position at the bottom of the material stirring area is used as the first marking position, and the position closest to the entrance of the material extrusion area is used as the second marking position.

[0069] Since the second mark position is closest to the material extrusion area, during the process of stirring the material in the stirring area, the material at the second mark position will be more evenly mixed than the material at the first mark position, and will be closer to the mixing standard required for the final product. Therefore, in each historical period, the mode of all flow rate values ​​in the flow rate time series data of the second mark position is used as the flow rate standard value. The reason for selecting the mode is that the mode represents the flow rate value with the highest frequency in the flow rate values ​​at the second mark position, that is, it represents the most typical and standard flow rate state; and the time corresponding to all flow rate standard values ​​is used as the reference time. The determination of the reference time is helpful to locate the state with better material mixing effect in the time dimension later.

[0070] Step S202: determining a comparison time in the first mark position, and adjusting the flow rate value at the comparison time based on the difference between the flow rate value at the comparison time and the flow rate standard value to determine the flow rate boundary value.

[0071] In step S201, in each historical cycle, a reference time, that is, a time when the material mixing effect is better, is determined based on the flow velocity time series data at the second mark position. Since the material mixing state at the first mark position is less uniform than that at the second mark position, but in the process of transporting the material from the first mark position to the second mark position, the stirring force in the stirring area is fixed, if a comparison time is determined in the flow velocity time series data at the first mark position based on the reference time, and a flow velocity range is determined based on the flow velocity value at the comparison time and the flow velocity value at the reference time, when the flow velocity value at the first mark position is within this flow velocity range, it can be regarded that after the stirring during the period between the first mark position and the second mark position, the state of the material at the second mark position can reach a uniformly mixed state.

[0072] The method for determining the comparison time includes: in the flow velocity time series data at the first mark position, taking the time at the same position as the reference time in the flow velocity time series data at the second mark position as the comparison time. For example: in the flow velocity time series data at the second mark position, if the reference time is the 7th time and the 9th time, then in the flow velocity time series data at the first mark position, the comparison time is also the 7th time and the 9th time.

[0073] The flow rate standard value determined in step S201 can be regarded as a boundary value in the flow rate range, and then another flow rate boundary value can be determined according to the flow rate value corresponding to the comparison moment in the first mark position.

[0074] The absolute value of the difference between the velocity value at each comparison moment and the velocity standard value is taken as the velocity difference factor. The velocity difference factor characterizes the fluctuation of the velocity value between the two marking positions. Then, among all the velocity difference factors, the occurrence probability of each velocity difference factor is calculated; and the velocity value at the comparison moment corresponding to the velocity difference factor is weightedly fused using the occurrence probability of the velocity difference factor to obtain the velocity boundary value. The weighted fusion method can comprehensively consider the influence of different velocity difference factors on the velocity boundary value, so that the final velocity boundary value is more reasonable and accurate. The formula model of the velocity boundary value can be specifically, for example:

[0075]

[0076] in, Indicates the velocity boundary value corresponding to each historical period; Indicates The probability of occurrence corresponding to the velocity difference factor of the velocity value at the comparison moment; Indicates The flow rate value at the comparison moment; Indicates the number of comparison moments.

[0077] In the formula model of the velocity boundary value, the absolute value of the difference between the velocity value at the comparison time and the corresponding reference time is calculated as the velocity difference factor ,in, Indicates The flow rate value at the reference moment corresponding to the comparison moment, when the value is larger, it means that the flow rate values ​​of the materials at the two positions are greatly different. It can be regarded as that at the same moment, the mixing state of the material at the first mark position is greatly different from the mixing state of the material at the second mark position. Conversely, it is regarded as that at the same moment, the mixing state of the material at the first mark position is less different from the mixing state of the material at the second mark position. Then the probability of occurrence of each flow rate difference factor is counted, that is, the ratio of the number of occurrences of each flow rate difference factor to the number of all comparison moments is calculated to obtain the probability of occurrence. The larger the probability of occurrence, the more times the flow rate value corresponding to the comparison moment appears, and it is more likely to be used as a boundary value of the flow rate range. Because the flow rate difference factors corresponding to different comparison moments may be the same, the value after the normalization of the sum is finally performed using the probability of occurrence of the flow rate difference factor. The flow velocity values ​​at the corresponding comparison moments are weighted and fused to determine a flow velocity boundary value.

[0078] Step S203: In each historical period, a normal flow rate range is determined based on the flow rate standard value and the flow rate boundary value, and the normal flow rate ranges corresponding to all historical periods are combined to determine a normal flow rate interval for uniform material mixing.

[0079] Based on the above steps, a flow rate boundary value and a flow rate standard value can be determined in each historical period. These two values ​​are used as a boundary value (the smaller value is the lower boundary value and the larger value is the upper boundary value), and the normal flow rate range corresponding to each historical period can be obtained.

[0080] In order to obtain a more accurate and comprehensive flow rate range, the intersection of the normal flow rate ranges of all historical cycles can be used as the normal flow rate range for uniform material mixing. At this time, if the flow rate value of the first mark position at the current moment is within the normal flow rate range, then when the material at the first mark position is mixed and transported to the second mark position, the possibility that its mixing state meets the standard mixing state will be higher.

[0081] It should be noted that in some special cases, when obtaining the normal flow rate interval based on the intersection, the intersection of some normal flow rate ranges may be an empty set. In this case, the following method can be used to obtain the normal flow rate interval:

[0082] The smaller of the two boundary values ​​in all normal flow rate ranges is taken as a boundary value of the normal flow rate interval. Similarly, the larger of the two boundary values ​​in all normal flow rate ranges is taken as a boundary value of the normal flow rate interval, thereby obtaining the normal flow rate interval.

[0083] It should be noted that the normal flow rate interval can be an open interval or a closed interval, which can be selected according to the implementation scenario and is not limited here.

[0084] At this point, the normal flow rate range when the materials are mixed evenly can be determined.

[0085] Step S3: In each historical cycle, the data values ​​in the flow rate time series data of each position are screened based on the normal flow rate range to determine the target time; in all historical cycles, the numerical characteristics of the temperature time series data at the two positions at the target time are integrated to determine the normal temperature range for uniform material mixing.

[0086] In the above steps, it can be determined that the normal flow rate range of the material at the first marked position should be when the materials are mixed evenly. However, the uniform mixing state of the materials is not only reflected in the flow rate of the materials, but also in the change in temperature. This is because when the melting and mixing conditions of different component materials change, the temperature distribution of the molten material will also change accordingly. Therefore, after determining the normal flow rate range, the normal temperature range corresponding to the material at the first marked position when the materials are mixed evenly can be determined on this basis.

[0087] First, in each historical cycle, the flow rate values ​​in the flow rate time series data at two positions are screened based on the normal flow rate range to determine the target time, which is the time when the flow rate value meets the uniform mixing state of the materials.

[0088] Preferably, in one embodiment of the present invention, the method for acquiring the target time includes:

[0089] In each historical cycle, in the flow velocity time series data of two locations, traversal starts from the first moment. When the flow velocity values ​​corresponding to the moments at the same positions in the flow velocity time series data of the two locations exist in the normal flow velocity range corresponding to the historical cycle at the same time, the currently traversed moment in the flow velocity time series data of the two locations is used as the target moment in each historical cycle.

[0090] An example of the method for obtaining the target moment is given: for the flow rate time series data at the first mark position and the second mark position, determine whether the two flow rate values ​​at the first moment exist in the normal flow rate range at the same time. If so, take the first moment as the target moment, then determine whether the two flow rate values ​​at the second moment exist in the normal flow rate range at the same time. If not, continue to determine whether the two flow rate values ​​at the third moment exist in the normal flow rate range at the same time. If so, take the third moment as the target moment, and so on, until all moments are determined and all target moments are obtained.

[0091] The material at the target time indicates that the material flow rate meets the standard of uniform material mixing, so the temperature value of the temperature time series data at the target time is further analyzed to determine the normal temperature range for uniform material mixing.

[0092] Preferably, in one embodiment of the present invention, the method for obtaining the normal temperature range includes:

[0093] See also Figure 7 , which shows a method flow chart of a method for obtaining a normal temperature range in one embodiment of the present invention, the method comprising the following steps:

[0094] Step S301: In each historical period, a normal temperature range is determined based on the numerical characteristics of the temperature values ​​at the target time in two temperature time series data.

[0095] Since the mean can represent the average level of a group of data, in the temperature time series data at each position in each historical period, the mean of the temperature values ​​corresponding to the target time is used as the temperature boundary value corresponding to each position. At this time, the temperature time series data at the first mark position and the second mark position both correspond to a temperature boundary value, and then these two temperature boundary values ​​are respectively used as the two boundary values ​​of the normal temperature range (the smaller value is the lower boundary value, and the larger value is the upper boundary value) to determine the normal temperature range.

[0096] Step S302: Determine the normal temperature range for uniform material mixing by integrating the normal temperature ranges corresponding to all historical cycles.

[0097] The intersection of the normal temperature ranges of all historical cycles is taken as the normal temperature range for uniform material mixing.

[0098] It should be noted that in some special cases, when obtaining the normal temperature range based on the intersection, the intersection of some normal temperature ranges may be an empty set. In this case, the following method can be used to obtain the normal temperature range:

[0099] The smaller of the two boundary values ​​in all normal temperature ranges is taken as a boundary value of the normal temperature interval. Similarly, the larger of the two boundary values ​​in all normal temperature ranges is taken as a boundary value of the normal temperature interval, thereby obtaining the normal temperature interval.

[0100] It should be noted that the normal temperature interval can be an open interval or a closed interval, which can be selected according to the implementation scenario and is not limited here.

[0101] Step S4: Based on the deviation between the flow velocity value at the central position at the current moment and the flow velocity value in the normal flow velocity range, as well as the deviation between the temperature value at the central position at the current moment and the temperature value in the normal temperature range, the motor speed of the rotating shaft in the material extrusion area is adjusted to determine the motor speed at the next moment.

[0102] Considering that the central position, that is, the first mark position, is far away from the material extrusion area, if the flow rate value at the first mark position at the current moment is within the normal flow rate range and the temperature value is within the normal temperature range, then after the time of being transported from the first mark position to the second mark position, the material will also be in a standard state of uniform mixing. Therefore, based on the deviation between the flow rate value of the material at the first mark position at the current moment and the flow rate value in the normal flow rate range and the deviation between the temperature value and the temperature value in the normal temperature range, the mixing state of the material can be judged, thereby adjusting the motor speed of the rotating shaft in the material extrusion area to make the speed in the material extrusion area consistent with the state of the material in the material stirring area.

[0103] Preferably, in one embodiment of the present invention, based on the deviation between the flow velocity value at the central position at the current moment and the flow velocity value in the normal flow velocity range, and the deviation between the temperature value at the central position at the current moment and the temperature value in the normal temperature range, the motor speed of the rotating shaft in the material extrusion area is adjusted to determine the motor speed at the next moment, comprising:

[0104] See also Figure 8 , which shows a method flow chart of a method for obtaining the motor speed at the next moment in one embodiment of the present invention, the method comprising the following steps:

[0105] Step S401: Determine a normal flow rate difference factor based on the deviation between the flow rate value at the central position at the current moment and the flow rate value within the normal flow rate interval.

[0106] Based on the deviation between the flow velocity value at the central position at the current moment and the flow velocity value in the normal flow velocity range, determine the normal flow velocity difference factor: Since the minimum value represents the time after the material is transported from the first mark position to the second mark position, in order to ensure uniform mixing, the minimum value in the normal flow velocity range is used as the flow velocity characteristic value, and the flow velocity characteristic value can be used as a relatively stable flow velocity reference value. Then, the absolute value of the difference between the flow velocity value at the central position at the current moment and the flow velocity characteristic value is normalized and used as the normal flow velocity difference factor. The formula model of the normal flow velocity difference factor can be, for example, as follows:

[0107]

[0108] in, represents the normal difference factor of flow rate; Indicates the flow velocity value at the central position at the current moment; represents the characteristic value of flow velocity; Represents the normalization function.

[0109] In the formula model of the normal difference factor of flow velocity, if the deviation between the flow velocity value at the central position at the current moment and the flow velocity characteristic value is greater, then the difference value The larger the difference is, the worse the approximation between the velocity value at the central position and the velocity characteristic value is. The smaller the value is, the closer the flow velocity value at the central position at the current moment is to the flow velocity characteristic value. The difference value is normalized to obtain the normal flow velocity difference factor. The smaller the normal flow velocity difference factor is, the closer the flow velocity value at the central position at the current moment is to the flow velocity characteristic value in the mixed uniform state.

[0110] Step S402: determining a normal temperature difference factor based on the deviation between the temperature value at the central position at the current moment and the temperature value in the normal temperature range.

[0111] Similarly, based on the deviation between the temperature value at the central position at the current moment and the temperature value in the normal temperature range, the temperature normal difference factor is determined: the minimum value of all temperature values ​​in the normal temperature range is taken as the temperature characteristic value, and the absolute value of the difference between the temperature value at the central position at the current moment and the temperature characteristic value is normalized as the temperature normal difference factor. The formula model of the temperature normal difference factor can be, for example, as follows:

[0112]

[0113] in, represents the normal difference factor of temperature; Indicates the temperature value at the central position at the current moment; Indicates the temperature characteristic value; Represents the normalization function.

[0114] In the formula model of the temperature normal difference factor, if the deviation between the temperature value at the central position at the current moment and the temperature characteristic value is greater, then the difference value The larger the difference is, the worse the degree of convergence between the temperature value at the central position and the temperature characteristic value at the current moment is; conversely, when the difference is The smaller the value is, the closer the temperature value at the central position at the current moment is to the corresponding characteristic value. The difference value is normalized to obtain the normal temperature difference factor. The smaller the normal temperature difference factor is, the closer the temperature value at the central position at the current moment is to the temperature characteristic value in the mixed uniform state.

[0115] Step S403: adjusting the motor speed of the motor of the rotating shaft in the material extrusion area at the current moment based on the normal flow rate difference factor and the normal temperature difference factor to obtain the motor speed at the next moment.

[0116] The normalized value of the sum of the flow rate normal difference factor and the temperature normal difference factor is used as the adjustment weight. The larger the adjustment weight, the larger the deviation between the flow rate value and the flow rate characteristic value of the material at the central position at the current moment, and the larger the deviation between the temperature value and the temperature characteristic value. In the subsequent process, the speed of the material extrusion area can be adjusted to a greater extent. Therefore, the product of the adjustment weight and the preset adjustment value is used as the speed adjustment amount, which is recorded as , where the normalization method can be used Normalization function, as an example, in the embodiment of the present invention, the preset adjustment value is set to 3, and the specific value needs to be adjusted according to the implementation scenario and is not limited here.

[0117] Finally, the motor speed of the motor used to drive the rotating shaft in the material extrusion area is adjusted at the current moment according to the speed adjustment amount to obtain the motor speed at the next moment, and the motor speed at the current moment is positively correlated with the motor speed at the next moment. Among them, since the normal temperature range is calculated based on the normal flow rate range, the normal flow rate range is still used as the benchmark here. If the flow rate value at the central position at the current moment is within the normal flow rate range, then the speed adjustment amount is positively correlated with the motor speed at the next moment. Conversely, if the flow rate value at the central position at the current moment is not within the normal flow rate range, then the speed adjustment amount is negatively correlated with the motor speed at the next moment. The formula model of the motor speed at the next moment can be specifically, for example:

[0118]

[0119] in, Indicates the motor speed at the next moment; Indicates the motor speed at the current moment; Indicates preset parameters; Indicates the speed adjustment amount.

[0120] In the above formula model, if the flow rate value at the central position at the current moment is within the normal flow rate range, it means that the mixing state of the material at the central position at this time can reach the standard state of uniform mixing after the mixing process from the central position to the second mark position, so the speed of the material extrusion area can be increased, then the preset parameter should be set to a positive number, so as to achieve a positive correlation between the speed adjustment amount and the motor speed at the next moment, which plays a role in improving the production efficiency of the plastic protective tube; on the contrary, if the flow rate value at the central position at the current moment is not within the normal flow rate range, it means that the mixing state of the material at the central position at this time is difficult to reach the standard state of uniform mixing after the mixing process from the central position to the second mark position, so the speed of the material extrusion area should be reduced, then the preset parameter should be set to a negative number, so as to achieve a negative correlation between the speed adjustment amount and the motor speed at the next moment, which plays a role in increasing the time the material stays in the stirring area, thereby giving the material more mixing time to ensure the quality of subsequent products.

[0121] It should be noted that, in order to prevent over-adjustment, in the embodiment of the present invention, when the preset parameter is a positive number, it is set to 1; when the preset parameter is a negative number, it is set to -1.

[0122] At this point, by determining the normal flow rate and temperature range when the materials are evenly mixed, detecting and comparing the difference between the current flow rate and temperature and the normal range in real time, dynamically adjusting the extrusion motor speed to ensure that the extrusion speed matches the degree of stirring and mixing, real-time response control is achieved, effectively improving the production rate and product quality of plastic protective tubes.

[0123] In summary, by dividing the device into a material stirring area and a material extrusion area, and installing temperature sensors and flow rate sensors at key positions in the material stirring area—the bottom center and near the entrance of the material extrusion area, the material stirring process can be fully monitored, so that the motor speed of the rotating shaft in the material extrusion area can be controlled in real time according to the uniformity of the material stirring, thereby ensuring the production rate and product quality of the plastic protective tube. First, the flow rate time series data and temperature time series data at two positions within a preset number of historical cycles are obtained, and rich production data samples can be accumulated. Due to the different mixing states of materials at different positions in the stirring area, when it is closer to the material extrusion area, it is believed that its mixing state will be more uniform and more in line with production standards. On the contrary, when it is far away from the material extrusion area, that is, at the central position at the bottom of the material stirring area of ​​the device, the mixing uniformity of the material will be weaker; at the same time, the corresponding properties of the material will change in different mixing states, which will lead to corresponding changes in the flow rate and temperature. Therefore, by analyzing the numerical characteristics and differences between the flow rate time series data of the materials at two positions in all historical cycles, the normal flow rate range for uniform material mixing can be determined to reflect the range of the material flow rate under normal circumstances when the materials are uniformly mixed. Next, in view of the different degrees of material mixing, the temperature will also change. Therefore, in each historical cycle, the moment corresponding to the flow rate value that meets the normal flow rate range in the flow rate time series data at each position is screened out as the target moment. The material state at the target moment can be regarded as having reached a uniformly mixed state at the flow rate analysis level. Then, in all historical cycles, the numerical characteristics of the temperature values ​​in the two temperature time series data at the target moment are combined to determine the normal temperature range for uniform material mixing. The normal temperature range reflects the range of the material temperature under normal circumstances when the materials are uniformly mixed. Furthermore, the flow velocity value and temperature value at the central position at the current moment can be obtained, and the motor speed in the material extrusion area can be dynamically adjusted by comparing the deviation of the flow velocity value from the flow velocity value in the normal flow velocity range and the deviation of the temperature value from the temperature value in the normal temperature range, so that the extrusion speed of the material extrusion area at the next moment can match the mixing degree of the material in the material stirring area. This instant response control method can more accurately judge the mixing uniformity of the material, thereby ensuring the production rate and product quality of the plastic protective tube.

[0124] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0125] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A plastic protective tube production extrusion device, characterized in that: The plastic protective tube production extrusion device comprises a heating cylinder, which is divided into a material stirring area and a material extrusion area. A temperature sensor and a flow rate sensor are installed at the central position of the bottom of the material stirring area and at the entrance of the material extrusion area. The temperature sensor is used to obtain the temperature time series data when the material is stirred, and the flow rate sensor is used to obtain the flow rate time series data when the material is stirred; a motor for driving a rotating shaft in the material extrusion area is installed in the material extrusion area, and the motor is also provided with a motor control module, and the motor control module is used to control the speed of the motor according to the temperature time series data and the flow rate time series data of the material, wherein the motor speed control method comprises: Obtaining flow rate time series data and temperature time series data of materials at two locations within a preset number of historical periods; In all historical cycles, the numerical characteristics and differences between the flow rate time series data of the materials at two locations are integrated to determine the normal flow rate range for uniform material mixing; In each historical cycle, the data values ​​in the flow rate time series data of each location are screened based on the normal flow rate range to determine the target time; in all historical cycles, the numerical characteristics of the temperature time series data of the two locations at the target time are integrated to determine the normal temperature range for uniform material mixing; Based on the deviation between the flow velocity value at the central position at the current moment and the flow velocity value in the normal flow velocity range, and the deviation between the temperature value at the central position at the current moment and the temperature value in the normal temperature range, the motor speed of the rotating shaft in the material extrusion area is adjusted to determine the motor speed at the next moment; The method for obtaining the normal flow rate interval includes: The central position at the bottom of the material stirring area is used as the first marking position, and the entrance position of the material extrusion area is used as the second marking position; In each historical period, based on the numerical characteristics of the flow velocity value in the flow velocity time series data at the second marking position, a flow velocity standard value and a reference time are determined; In each historical cycle, in the flow velocity time series data at the first mark position, the moment at the same position as the reference moment in the flow velocity time series data at the second mark position is used as the comparison moment; based on the difference between the flow velocity value at the comparison moment and the flow velocity standard value, the flow velocity value at the comparison moment is adjusted to determine the flow velocity boundary value; In each historical period, a normal flow rate range is determined based on the flow rate standard value and the flow rate boundary value; The intersection of the normal flow rate ranges of all historical cycles is taken as the normal flow rate range for uniform material mixing.

2. A plastic protective tube production extrusion device according to claim 1, characterized in that: The method of determining the flow rate standard value and the reference time based on the numerical characteristics of the flow rate value in the flow rate time series data at the second mark position in each historical period includes: In each historical period, the mode of all flow velocity values ​​in the flow velocity time series data at the second mark position is used as the flow velocity standard value, and the time corresponding to all flow velocity standard values ​​is used as the reference time.

3. A plastic protection tube production extrusion device according to claim 1, characterized in that: The method for obtaining the flow velocity boundary value comprises: The absolute value of the difference between the flow velocity value at each comparison moment and the standard flow velocity value is taken as a flow velocity difference factor; among all the flow velocity difference factors, the occurrence probability of each flow velocity difference factor is calculated; The velocity values ​​at the comparison moments corresponding to the velocity difference factors are weightedly fused using the occurrence probabilities of all velocity difference factors to obtain the velocity boundary value.

4. A plastic protection tube production extrusion device according to claim 1, characterized in that: The method for obtaining the target time includes: In each historical cycle, in the two flow velocity time series data, traversal starts from the first moment. When the flow velocity values ​​corresponding to the moments at the same position in the two flow velocity time series data exist in the normal flow velocity range at the same time, the currently traversed moment in the two flow velocity time series data is used as the target moment in each historical cycle.

5. A plastic protection tube production extrusion device according to claim 1, characterized in that: The method for obtaining the normal temperature range includes: In each historical period, the normal temperature range is determined based on the numerical characteristics of the temperature values ​​at the target time in the two temperature time series data; The intersection of the normal temperature ranges of all historical cycles is taken as the normal temperature range for uniform material mixing.

6. A plastic protection tube production extrusion device according to claim 5, characterized in that: The method for obtaining the normal temperature range includes: In the temperature time series data at each position in each historical period, the average of the temperature values ​​corresponding to the target time is used as the temperature boundary value corresponding to each position, and the normal temperature range is determined based on the temperature boundary values ​​at the two positions.

7. A plastic protection tube production extrusion device according to claim 1, characterized in that: The method for obtaining the motor speed at the next moment includes: Based on the deviation between the flow velocity value at the central position at the current moment and the flow velocity value within the normal flow velocity interval, a normal flow velocity difference factor is determined; Determine the temperature normal difference factor based on the deviation between the temperature value at the central position at the current moment and the temperature value in the normal temperature range; The normalized value of the sum of the flow rate normal difference factor and the temperature normal difference factor is used as an adjustment weight, and the product of the adjustment weight and the preset adjustment value is used as a speed adjustment amount; The motor speed of the motor of the rotating shaft in the material extrusion area at the current moment is adjusted according to the speed adjustment amount to obtain the motor speed at the next moment, and the motor speed at the current moment is positively correlated with the motor speed at the next moment, wherein, if the flow velocity value at the central position at the current moment is within the normal flow velocity range, then the speed adjustment amount is positively correlated with the motor speed at the next moment, and if the flow velocity value at the central position at the current moment is not within the normal flow velocity range, then the speed adjustment amount is negatively correlated with the motor speed at the next moment.

8. A plastic protection tube production extrusion device according to claim 7, characterized in that: The method for obtaining the normal flow rate difference factor includes: Taking the minimum value of all flow velocity values ​​within the normal flow velocity interval as the flow velocity characteristic value; The value obtained by normalizing the absolute value of the difference between the flow velocity value at the central position at the current moment and the flow velocity characteristic value is used as the flow velocity normal difference factor.

9. A plastic protection tube production extrusion device according to claim 7, characterized in that: The method for obtaining the normal temperature difference factor includes: Taking the minimum value of all temperature values ​​within the normal temperature range as the temperature characteristic value; The value obtained by normalizing the absolute value of the difference between the temperature value at the central position at the current moment and the temperature characteristic value is used as the temperature normal difference factor.

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