A method to prevent calendering rolls from colliding due to material breakage

Abstract

This invention discloses a method for preventing calender rolls from colliding due to material breakage, belonging to the field of calender control technology. The method includes the following steps: S1, using an infrared monochromatic thermometer to detect the surface temperature of the calender rolls; S2, calibrating the detected surface temperature of the calender rolls against a defined temperature range; S3, if the detected surface temperature of the calender rolls is outside the defined temperature range, a response action is executed; if the detected surface temperature of the calender rolls is within the defined temperature range, the next detection cycle begins. Based on the characteristic of the temperature difference between the coated and uncoated surfaces of the calender rolls under normal calender operation, a temperature detection device is set up to detect the temperature status of the coated or uncoated surfaces of the calender rolls under operating conditions, thereby determining whether there is a material breakage and idling situation, issuing an alarm in a timely manner, and shutting down the calender to avoid damage to the calender rolls due to idling, thus optimizing the calender's operating mechanism.

Description

Technical Field

[0001] This invention relates to the field of calender control technology, and in particular to a method for preventing calender rolls from colliding due to material breakage. Background Technology

[0002] Existing calenders mainly consist of calendering rolls, a frame, a roll gap adjustment device, a roll temperature adjustment device, a transmission device, a lubrication system, a control system, and a roll removal device. Currently, four-roll and five-roll calenders are the most common. During calendering, the thickness of the calendered film is controlled by adjusting the gap between the calendering rolls using the roll gap adjustment device. When the calendered film thickness is less than 0.1mm, the gap between the calendering rolls is much smaller than 0.1mm. During normal production, the material stored between the two sets of calendering rolls will widen the gap when entering it, preventing collisions between the calendering rolls. However, because the gap between the calendering rolls is very small, collisions and wear can easily occur during idling, leading to surface damage to the calendering rolls, or even the complete scrapping of the calendering rolls, resulting in high maintenance costs. Furthermore, after a material breakage, the subsequent portion of the film produced in continuous production will gradually shrink and narrow, failing to meet the required width, and ultimately having to be treated as waste, significantly increasing production costs. Summary of the Invention

[0003] In order to overcome the defects of the existing technology, the present invention provides a method for preventing calendering rollers from colliding due to material breakage.

[0004] The technical solution adopted by this invention to solve its technical problem is: a method for preventing calendering rollers from colliding due to material breakage, comprising the following steps:

[0005] S1. Detect the temperature of the surface area of ​​the calendering roll;

[0006] S2. The detected surface temperature of the calender roll is compared with the specified temperature range;

[0007] S3. If the detected temperature of the calender roll surface area is outside the specified temperature range, then execute the response action;

[0008] If the detected temperature of the calender roll surface area is within the specified temperature range, then proceed to the next detection cycle.

[0009] Preferably, the response actions include, but are not limited to, issuing an alarm or shutting down the equipment.

[0010] Preferably, in step S1, while the calender is in operation, the surface temperature of the calender roll is detected by setting multiple detection points, wherein the detection points are set at locations including the coated surface and the non-coated surface on the calender roll.

[0011] Preferably, in step S1, when setting the detection points, detection points are set on at least one set of calendering rollers on both the coated and uncoated surfaces.

[0012] Preferably, in step S1, when setting the detection points, multiple detection points are set at least at axial intervals along a set of calendering rolls.

[0013] Preferably, the number of detection points and the axial spacing on the same group of calendering rolls are determined by the length of the calendering rolls, and the temperature detection equipment of the same group of calendering rolls is connected to the same temperature controller.

[0014] Preferably, step S0 is also included;

[0015] In step S0, for different products being processed, the surface temperature of the coated surface and the surface temperature of the non-coated surface of the calender roll under normal working conditions are detected by a temperature detection device. Based on the surface temperature of the coated surface and the non-coated surface of the calender roll under normal working conditions, different temperature limits are set for different detection points. The temperature limits for the coated surface and the non-coated surface of the same calender roll are different.

[0016] Preferably, in step S0, if the detection temperature at different detection points is different under normal working conditions, then the corresponding limited temperature ranges for different detection points are different.

[0017] The defined temperature range for each detection point consists of the detection temperature of the corresponding detection point under normal operating conditions, plus a temperature fluctuation range.

[0018] Preferably, step S3 also includes step S3-1, which compares the temperature of the coated surface area of ​​the same calendering roller with the temperature of the uncoated surface area. If the temperature of the coated surface area of ​​the same calendering roller is equal to the temperature of the uncoated surface area, then a response action is performed.

[0019] Preferably, when detecting the temperature of the surface area of ​​the calendering roll, an infrared monochromatic thermometer is used as the temperature detection equipment.

[0020] The beneficial effects of this invention are as follows: Based on the temperature difference detected between the coated and uncoated surfaces of the calender rolls under normal operating conditions, by setting up temperature detection equipment, the temperature status of the coated or uncoated surfaces of the calender rolls under operating conditions can be detected in real time. This allows for the determination of whether the calender is running dry due to material shortage, timely alarm issuance, and shutdown of the calender, preventing further dry running that could damage the calender rolls. Compared with existing technologies, this invention further optimizes the calender's operating mechanism, reduces labor intensity, decreases the manpower cost of manual operation, and avoids production line shutdowns due to damage to the calender rolls caused by material shortage and dry running. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating an embodiment of the present invention;

[0022] Figure 2 This is a structural illustration of an embodiment of the present invention. Figure 1 ;

[0023] Figure 3 This is a structural illustration of an embodiment of the present invention. Figure 2 ;

[0024] Figure 4 This is a structural illustration of an embodiment of the present invention. Figure 3 ;

[0025] Figure 5 This is a structural illustration of an embodiment of the present invention. Figure 4 ;

[0026] Figure 6 This is a structural illustration of an embodiment of the present invention. Figure 5 ;

[0027] Figure 7 This is a structural illustration of an embodiment of the present invention. Figure 6 . Detailed Implementation

[0028] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] As attached Figure 1 As shown, the present invention provides a method for preventing calendering rollers from colliding due to material breakage, comprising the following steps:

[0030] S0. For processing different products, the surface temperature of the coated surface and the surface temperature of the uncoated surface of the calender roller under normal working conditions are detected by temperature detection equipment. Based on the surface temperature of the coated surface and the uncoated surface of the calender roller under normal working conditions, different temperature limits are set for different detection points. Since the surface temperature of an object with high emissivity tends to its true temperature when performing infrared thermometry, and the surface temperature of an object with low emissivity tends to its surrounding ambient temperature, the surface temperature of the calender roller covered with film tends to be closer to the set temperature of the calender roller, while the surface temperature of the uncoated surface tends to be closer to its surrounding ambient temperature. Therefore, the temperature limits for the coated surface and the uncoated surface of the same calender roller are different.

[0031] In step S0, if the detection temperature at different detection points is different under normal working conditions, then the corresponding limited temperature ranges for different detection points will be different.

[0032] The defined temperature range of the detection point is composed of the detection temperature of the corresponding detection point under normal working conditions, plus a temperature fluctuation range.

[0033] Taking PVC film production as an example, when the calendering roller is set to a temperature of 160-180℃, the surface temperature of the coated side of the calendering roller is generally 170-190℃, and the surface temperature of the non-coated side of the calendering roller is generally 70-80℃. When detecting the surface temperature of the calendering roller, an infrared monochromatic thermometer is used.

[0034] S1. When the calender is in operation, the surface temperature of the calender roll is detected by setting at least one detection point, wherein the detection point is set at at least one of the coated surface and the non-coated surface on the calender roll.

[0035] S2. The surface temperature of the calender roll at the corresponding detection point is compared with the defined temperature range of the corresponding detection point;

[0036] S3. If the surface temperature of the calender roll at the corresponding detection point is outside the specified temperature range of the corresponding detection point, that is, the calender roll of the calender has a material breakage fault, then a response action is executed to prevent the calender roll from being damaged due to collision caused by the material breakage and idling. The above response action includes, but is not limited to, issuing an alarm and stopping the equipment.

[0037] If the temperature of the calender roll surface area at the corresponding detection point is within the specified temperature range for that detection point, then proceed to the next detection cycle.

[0038] Specifically, based on the temperature difference detected between the coated and uncoated surfaces of the calender rolls under normal operating conditions, a temperature detection device is installed to monitor the temperature of the coated or uncoated surfaces of the calender rolls in real time during operation. This allows for the determination of whether the calender is running dry due to material shortage, prompting an alarm and shutdown of the calender to prevent further dry running and damage to the calender rolls. Compared to existing technologies, this further optimizes the calender's operating mechanism, reduces labor intensity, lowers the manpower cost of manual operation, and prevents production line shutdowns due to calender roll damage caused by material shortage and dry running.

[0039] Example 1

[0040] See appendix Figure 2 -3. An infrared monochromatic thermometer is installed on the outside of the non-coated surface of one of the calendering rollers. In the figure, the arrow on the black line indicates the direction of film material conveying, and the black dot and the arrow on the black dot indicate the setting position and detection direction of the infrared monochromatic thermometer (the same below).

[0041] Taking the production of PVC film and the setting temperature of the calendering rollers as 160-180℃ as an example, if the temperature detected by the infrared monochromatic thermometer is less than 100℃, the calender is in normal working condition. If the temperature detected by the infrared monochromatic thermometer is greater than 150℃, it is determined that the calendering rollers of the calender are experiencing film material wrapping, triggering the calender controller to issue an alarm and simultaneously control the calendering rollers to stop running to prevent collisions between the calendering rollers.

[0042] Example 2

[0043] See appendix Figure 4 Infrared monochromatic thermometers are installed on the outer side of the non-coated surface of at least two sets of calendering rolls;

[0044] Taking the production of PVC film and the setting temperature of the calendering rollers as 160-180℃ as an example, if the detected temperature of both sets of infrared monochromatic thermometers is less than 100℃, the calender is in normal working condition. If the detected temperature of one set of infrared monochromatic thermometers is greater than 150℃, it is determined that the calendering rollers of the calender are experiencing film material wrapping, triggering the calender controller to issue an alarm and simultaneously control the calendering rollers to stop running to prevent collisions between the calendering rollers.

[0045] Example 3

[0046] See appendix Figure 5 Infrared monochromatic thermometers are installed on the outer side of the coating surface of at least two sets of calendering rollers;

[0047] Taking the production of PVC film with a calendering roller temperature set at 160-180℃ as an example, if the temperature detected by one of the infrared monochromatic thermometers is less than 150℃, it is determined that the calendering rollers are experiencing film wrapping, triggering the calender controller to issue an alarm and simultaneously stopping the calendering rollers to prevent collisions.

[0048] Furthermore, in step S1, when setting the detection points, detection points are set on at least one set of calendering rollers for both the coated and uncoated surfaces.

[0049] Specifically, Example 4

[0050] See appendix Figure 6 -7, infrared monochromatic thermometers are installed on the outer side of the coated and uncoated surfaces of at least one set of calendering rolls respectively;

[0051] Taking the production of PVC film and the setting temperature of the calendering rollers as 160-180℃ as an example, if the detected temperature of the film-coated surface of the calendering rollers is less than 150℃, or the detected temperature of the non-film-coated surface of the calendering rollers is greater than 150℃, it is determined that the calendering rollers of the calendering machine have a film wrapping phenomenon, triggering the calendering machine controller to issue an alarm and simultaneously control the calendering rollers to stop running to prevent collisions between the calendering rollers. Compared with using a single set of infrared monochromatic thermometers, the system using multiple sets of infrared monochromatic thermometers has higher reliability and avoids malfunctions caused by the failure of a single infrared monochromatic thermometer.

[0052] Furthermore, in step S1, when setting the detection points, at least a number of detection points are set at intervals along the axial direction of a set of calendering rollers to avoid local material breakage on the calendering rollers, where a single set of infrared monochromatic thermometers cannot trigger a response action in time, or the infrared monochromatic thermometers malfunction and cannot trigger a response action. If the calendering rollers continue to operate after material breakage, the width of the calendered film will gradually narrow and waste will be formed. The number of detection points and the axial spacing on the same set of calendering rollers are determined by the length of the calendering rollers. The detection points are symmetrical about the midpoint of the calendering rollers, and the temperature detection equipment of the same set of calendering rollers is connected to the same temperature controller.

[0053] Furthermore, step S3 also includes step S3-1, which compares the temperature of the coated surface area of ​​the same calendering roller with the temperature of the non-coated surface area. If the temperature of the coated surface area of ​​the same calendering roller is equal to the temperature of the non-coated surface area, then a response action is executed. Adding this judgment logic can avoid the problem of failing to trigger the response action due to incorrect parameter settings, reduce the risk of subsequent manual operation settings, and improve system reliability.

[0054] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A method for preventing calendering rollers from colliding due to material breakage, characterized in that, Includes the following steps: S0. For processing different products, temperature detection equipment is used to detect the surface temperature of the coated surface and the non-coated surface of the calender roll under normal operating conditions. Based on the surface temperature of the coated surface and the non-coated surface of the calender roll under normal operating conditions, different temperature limits are set for different detection points. The temperature limits for the coated surface and the non-coated surface of the same calender roll are different. The temperature limit for each detection point is formed by adding a temperature fluctuation range to the detection temperature of the corresponding detection point under normal operating conditions. S1. Detect the temperature of the surface area of ​​the calendering roll; S2. The detected surface temperature of the calender roll is compared with the specified temperature range; S3. If the detected temperature of the calender roll surface area is outside the specified temperature range, then execute the response action; If the detected temperature of the calender roll surface area is within the specified temperature range, then proceed to the next detection cycle.

2. The method for preventing calendering rollers from colliding due to material breakage according to claim 1, characterized in that, The response actions include, but are not limited to, issuing alarms and shutting down equipment.

3. The method for preventing calendering rollers from colliding due to material breakage according to claim 1, characterized in that, In step S1, while the calender is in operation, the surface temperature of the calender roll is detected by setting multiple detection points. The detection points are located on both the coated and uncoated surfaces of the calender roll.

4. The method for preventing calendering rollers from colliding due to material breakage according to claim 3, characterized in that, In step S1, when setting the detection points, detection points are set on at least one set of calendering rollers for both the coated and uncoated surfaces.

5. The method for preventing calendering rollers from colliding due to material breakage according to claim 3, characterized in that, In step S1, when setting the detection points, at least a number of detection points are set at intervals along the axial direction of a set of calendering rolls.

6. The method for preventing calendering rollers from colliding due to material breakage according to claim 5, characterized in that, The number of detection points and their axial spacing on the same group of calendering rolls are determined by the length of the calendering rolls, and the temperature detection equipment on the same group of calendering rolls is connected to the same temperature controller.

7. The method for preventing calendering rollers from colliding due to material breakage according to claim 1, characterized in that, In step S0, if the detection temperature at different detection points is different under normal working conditions, then the corresponding limited temperature ranges for different detection points will be different.

8. The method for preventing calendering rollers from colliding due to material breakage according to claim 3, characterized in that, Step S3 also includes step S3-1, which compares the temperature of the coated surface area of ​​the same calendering roller with the temperature of the uncoated surface area. If the temperature of the coated surface area of ​​the same calendering roller is equal to the temperature of the uncoated surface area, then a response action is performed.

9. The method for preventing calendering rollers from colliding due to material breakage according to claim 1, characterized in that, When detecting the surface temperature of the calendering roll, an infrared monochromatic thermometer is used as the temperature detection equipment.

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