Material conveying device and method of operation thereof

Abstract

This application provides a material conveying device and its operating method, comprising: a controller, a vibrating screen, a receiving device, a rotary valve connected between the inlet of the vibrating screen and the receiving device, a conveying pipe connected to the outlet of the receiving device, an air inlet pipe connected to the air inlet of the receiving device, an air inlet valve and a flow regulating valve connected to the air inlet pipe, and a pressure transmitter for detecting the internal pressure of the material conveying device; the controller is communicatively connected to the rotary valve, the air inlet valve, the flow regulating valve, and the pressure transmitter, enabling the controller to determine whether there is a blockage based on the rotational speed or internal pressure of the rotary valve, and to automatically clear the blockage by controlling the rotary valve, the air inlet valve, and the flow regulating valve when a blockage occurs. This application can automatically clear blockages, thereby allowing the air intake to be controlled to be smaller during the conveying stage, thereby increasing the conveying concentration, reducing the conveying speed, reducing the chip breakage rate, and alleviating chip stringing and material spraying phenomena in the daily feed bin.

Description

Technical Field

[0001] This application relates to the field of plastic slice conveying technology, and in particular to a material conveying device capable of conveying plastic slices and a method for operating the material conveying device. Background Technology

[0002] There are many types of plastic chips, but they are basically granules, with a particle size of approximately Φ3.0mm × 3.0mm and a bulk density of approximately 700kg / m³. 3 ~900kg / m 3 .

[0003] Rotary valve conveying systems are generally used to transport plastic chips. Current rotary valve conveying systems have lower conveying concentrations and higher conveying speeds, which reduces the risk of pipe blockage. However, this can lead to problems such as high chip breakage rates, severe chip stringing within the conveying system, and material spraying from the daily feed hopper.

[0004] Therefore, how to alleviate or avoid the above-mentioned drawbacks is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] This application provides a material conveying device, which includes: a controller, a vibrating screen, a receiving device, a rotary valve connected between the inlet of the vibrating screen and the receiving device, a conveying pipe connected to the outlet of the receiving device, an air inlet pipe connected to the air inlet of the receiving device, an air inlet valve and a flow regulating valve connected to the air inlet pipe, and a pressure transmitter for detecting the internal pressure of the material conveying device.

[0006] The controller is communicatively connected to the rotary valve, the inlet valve, the flow regulating valve, and the pressure transmitter, enabling the controller to determine whether there is a blockage based on the rotational speed of the rotary valve or the detection data of the pressure transmitter, and to automatically clear the blockage by controlling the rotary valve, the inlet valve, and the flow regulating valve when a blockage occurs.

[0007] One embodiment of the material conveying device includes a buffer chamber connected between the vibrating screen and the rotary valve. A level gauge is connected to the upper part of the buffer chamber, and a controller is communicatively connected to the level gauge, enabling the controller to control the vibrating screen to stop operating when the material level in the buffer chamber reaches a set value.

[0008] In one embodiment of the material conveying device, an expansion joint is connected between the vibrating screen and the material bin, as well as between the vibrating screen and the buffer bin.

[0009] In one embodiment of the material conveying device, the rotary valve is equipped with a rotary valve exhaust pipe, the exhaust port of the rotary valve exhaust pipe is connected to the upper part of the buffer bin, the upper part of the buffer bin is equipped with a buffer bin exhaust port, and the connection position of the level gauge to the buffer bin is lower than the connection position of the exhaust port of the rotary valve exhaust pipe to the buffer bin.

[0010] One embodiment of the material conveying device includes a pressure reducing valve connected to the air inlet pipe, and a controller communicatively connected to the pressure reducing valve so that the controller can regulate the air inlet pressure by controlling the pressure reducing valve.

[0011] One embodiment of a material conveying device includes a safety valve connected to an air inlet pipe, and a filter screen is provided between the safety valve and the air inlet pipe.

[0012] This application also provides a method for operating a material conveying device, wherein the material conveying device is any of the above-mentioned material conveying devices, and the method for operating includes the following stages: first entering the start-up stage, then entering the conveying stage after start-up, then entering the automatic unblocking stage if pipe blockage occurs in the conveying stage, and entering the shutdown stage after receiving a shutdown signal.

[0013] During the startup phase, the air intake valve is opened and the flow regulating valve is set to the initial opening M. After opening the air intake valve, the rotary valve is opened after a set delay. After opening the rotary valve, the vibrating screen is started after a set delay.

[0014] During the conveying stage, the following methods are used to determine if there is any pipe blockage:

[0015] When the current rotational speed of the rotary valve is less than a multiple of the set rotational speed of the rotary valve, it is determined that there is a blockage.

[0016] When the current internal pressure of the material conveying device is greater than the first pressure setting value P1, the vibrating screen is stopped. If the current internal pressure of the material conveying device is less than the second pressure setting value P2 after the vibrating screen is stopped, the vibrating screen is started. If the current internal pressure of the material conveying device is greater than the third pressure setting value P3 after the vibrating screen is stopped, it is determined that there is a pipe blockage.

[0017] During the automatic congestion clearing phase, automatic congestion clearing is achieved through the following methods:

[0018] First, close the rotary valve and the intake valve, and adjust the opening of the flow regulating valve to M3;

[0019] The second step is to determine whether the current internal pressure of the material conveying device is less than the fourth pressure setting value P4. If so, the air inlet valve is opened.

[0020] Third, if the current internal pressure of the material conveying device after opening the air inlet valve is less than the fourth pressure setting value P4, then close the air inlet valve to complete the unblocking; if the current internal pressure of the material conveying device after opening the air inlet valve is greater than the fifth pressure setting value P5, then close the air inlet valve and return to the second step.

[0021] Among them, M > M3, P3 > P5 > P1 > P2 > P4.

[0022] One embodiment of the operation method of the material conveying device includes a buffer silo connected between the vibrating screen and the rotary valve, with a level gauge connected to the upper part of the buffer silo. During the conveying phase, if the material level in the buffer silo reaches a set level, the vibrating screen is stopped; when the material level in the buffer silo drops below the set level, the vibrating screen is restarted.

[0023] In one embodiment of the operation method of the material conveying device, the pressure reducing valve is controlled to adjust the inlet pressure to no more than 0.4 MPa during the start-up stage, the conveying stage, and the automatic unblocking stage.

[0024] In one embodiment of the operation method of the material conveying device, during the shutdown phase, the vibrating screen is shut down. If the current internal pressure of the material conveying device is less than the fourth pressure setting value P4 after the vibrating screen is shut down, the rotary valve is closed after a set delay time, and the opening of the flow regulating valve is increased stepwise. After maintaining each opening setting time, the air inlet valve is closed.

[0025] This application, due to its automatic unblocking capability, allows for a smaller intake air volume during the conveying stage (achieved by setting a smaller initial opening M of the flow regulating valve). Controlling the intake air volume during the conveying stage can increase the conveying concentration, reduce the conveying speed, decrease the slice breakage rate, alleviate slice stringing, and reduce material spraying from the daily feed hopper. Attached Figure Description

[0026] Figure 1 A schematic diagram of one embodiment of the material conveying device provided in this application;

[0027] Figure 2 A schematic diagram of one embodiment of the screen mesh of a vibrating screen;

[0028] Figure 3 An overall flowchart of an embodiment of the operation method of the material conveying device provided in this application;

[0029] Figure 4 A flowchart of the startup phase of an embodiment of the operation method of the material conveying device provided in this application;

[0030] Figure 5A flowchart of the conveying stage of an embodiment of the operation method of the material conveying device provided in this application;

[0031] Figure 6 A flowchart of the unblocking stage of an embodiment of the operation method of the material conveying device provided in this application;

[0032] Figure 7 A flowchart of the shutdown phase of an embodiment of the operation method of the material conveying device provided in this application;

[0033] The annotations in the attached figures are explained as follows:

[0034] 1. Material silo, 2. Gate valve, 3. First expansion joint, 4. Vibrating screen, 5. Second expansion joint, 6. Buffer silo, 7. Level gauge, 8. Buffer silo exhaust port, 9. Rotary valve, 10. Rotary valve exhaust pipe, 11. Acceleration chamber, 12. Air source, 13. Manual ball valve, 14. Pressure reducing valve, 15. Flow meter, 16. Inlet valve, 17. Flow regulating valve, 18. Safety valve, 19. Pressure transmitter, 20. Conveying pipeline, 21. Daily material silo, 22. Daily material silo exhaust port, 23. Filter screen, 24. Inlet pipeline. Detailed Implementation

[0035] This application provides a material conveying device and its operating method. In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] like Figure 1 As shown, the material conveying device provided in this application includes at least a controller (not shown in the figure), a vibrating screen 4, a receiving device (11 in the figure), a rotary valve 9 connected between the inlet of the vibrating screen 4 and the receiving device, a conveying pipe 20 connected to the outlet of the receiving device, an air inlet pipe 24 connected to the air inlet of the receiving device, an air inlet valve 16 and a flow regulating valve 17 connected to the air inlet pipe 24, and a pressure transmitter 19 for detecting the internal pressure of the material conveying device.

[0037] The controller is communicatively connected to the rotary valve 9, the inlet valve 16, the flow regulating valve 17, and the pressure transmitter 19, enabling the controller to determine whether there is a blockage based on the rotational speed of the rotary valve 9 or the detection data of the pressure transmitter 19, and to automatically clear the blockage by controlling the rotary valve 9, the inlet valve 16, and the flow regulating valve 17 when a blockage occurs.

[0038] More specifically, the pressure transmitter 19 can be connected to the air intake pipe 24.

[0039] More specifically, such as Figure 2As shown, the screen of vibrating screen 4 can be a perforated plate type. The screen holes can be circular. The center-to-center distance L of the screen holes can be set in the range of 3.5mm > L > 2mm to ensure the opening rate and screening efficiency of the screen. The aperture R of the screen holes can be set in the range of 2.5mm > R > 1.5mm to ensure that debris in the slices can be effectively screened out while normal slices are not screened out. The thickness H of the screen should preferably be no less than 2.5mm to ensure the strength of the screen.

[0040] More specifically, the receiving device can employ an acceleration chamber 11. The acceleration chamber 11 has a feed inlet at its upper end, an air inlet on its left side, and a discharge outlet on its right side. A tapering section is provided between the air inlet and the discharge outlet of the acceleration chamber 11. The cross-sectional area of ​​the tapering section gradually decreases from the side with the air inlet to the side with the discharge outlet, thus providing an acceleration function. The structure of the receiving device is not limited to this; it only needs to be able to receive materials and allow for the introduction and discharge of gas.

[0041] In the illustrated embodiment, the material conveying device further includes a buffer chamber 6. The buffer chamber 6 is connected between the vibrating screen 4 and the rotary valve 9. The interior of the buffer chamber 6 is a hollow structure. A level gauge 7 is connected to the upper part of the buffer chamber 6, and the controller is communicatively connected to the level gauge 7, enabling the controller to stop the vibrating screen 4 when the material level in the buffer chamber 6 reaches the set level.

[0042] In the illustrated embodiment, a first expansion joint 3 connects the vibrating screen 4 to the material bin 1; in other words, the vibrating screen 4 and the material bin 1 are connected via the first expansion joint 3. A second expansion joint 5 connects the vibrating screen 4 to the buffer bin 6; in other words, the vibrating screen 4 and the buffer bin 6 are connected via the second expansion joint 5. This prevents the excitation force of the vibrating screen 44 from being transmitted to the material bin 1 and the buffer bin 6, thus avoiding damage to them and ensuring the safe operation of the vibrating screen 4 itself.

[0043] In the illustrated embodiment, the rotary valve 9 is equipped with a rotary valve exhaust pipe 10. The exhaust port of the rotary valve exhaust pipe 10 is connected to the upper part of the buffer chamber 6, and the upper part of the buffer chamber 6 is equipped with a buffer chamber exhaust port 8. This allows gas leaking through the gap between the rotor and the housing of the rotary valve 9 during operation to be discharged. The connection position of the level gauge 7 to the buffer chamber 6 is lower than the connection position between the exhaust port of the rotary valve exhaust pipe 10 and the buffer chamber 6, which facilitates the smooth discharge of exhaust gas into the atmosphere through the buffer chamber exhaust port 88. The volume of the buffer chamber 6 below the connection position of the rotary valve exhaust pipe 10 and the buffer chamber 6 should preferably be no less than 70% of the total volume of the buffer chamber 6.

[0044] In the illustrated embodiment, the material conveying device includes a pressure reducing valve 14, which is connected to the air inlet pipe 24. The controller is communicatively connected to the pressure reducing valve 14 so that the controller can adjust the air inlet pressure by controlling the pressure reducing valve 14.

[0045] In the illustrated embodiment, the material conveying device includes a safety valve 18. The safety valve 18 is connected to the air inlet pipe 24. The opening pressure setting of the safety valve 18 is not greater than the design pressure of the rotary valve 9. A filter screen 23 is provided between the air inlet of the safety valve 18 and the air inlet pipe 24. This prevents material from entering the gap between the valve core and the valve housing of the safety valve 18 through the filter screen 23 when the safety valve 18 is open, thus preventing the valve core of the safety valve 18 from failing to reset when required. The aperture of the filter holes in the filter screen 23 is preferably no greater than 2.5 mm.

[0046] In the illustrated embodiment, the outlet of the conveying pipe 20 is connected to the top of the daily feed hopper 21. A daily feed hopper vent 22 is provided at the top of the daily feed hopper 21 to discharge any stale air inside. The diameter of the daily feed hopper vent 22 should preferably be no smaller than the diameter of the outlet of the conveying pipe 20.

[0047] In the illustrated embodiment, a manual valve, specifically a manual ball valve 13, is also connected to the air inlet pipe 24. A flow meter 15 is also connected to the air inlet pipe 24. A discharge valve, specifically a gate valve 2, is also connected to the discharge port of the material silo 1.

[0048] More specifically, in the illustrated embodiment, the material bin 1, gate valve 2, first expansion joint 3, vibrating screen 4, second expansion joint 5, buffer bin 6, rotary valve 9, acceleration chamber 11, manual ball valve 13, pressure reducing valve 14, flow meter 15, air inlet valve 16, flow regulating valve 17, safety valve 18, conveying pipeline 20, daily feed bin 21, and air inlet pipeline 24 can all be made of stainless steel.

[0049] like Figure 3 As shown, the operation method of the material conveying device provided in this application includes the following stages: First, entering the start-up stage. After start-up, entering the conveying stage. If pipe blockage occurs during the conveying stage, entering the automatic unblocking stage. After automatic unblocking is completed, the start-up stage can be entered again. Upon receiving a shutdown signal, entering the shutdown stage.

[0050] Because it can automatically clear blockages, the air intake can be controlled to be smaller during the conveying stage (achieved by setting the initial opening M of the flow regulating valve 17 to be smaller). Controlling the air intake to be smaller during the conveying stage can increase the conveying concentration, reduce the conveying speed, reduce the breakage rate of slices, alleviate the phenomenon of slice stringing, and alleviate the phenomenon of material spraying from the daily feed hopper 21.

[0051] like Figure 4 As shown, during the startup phase, the air intake valve 16 is opened. After a set delay following the opening of the air intake valve 16, the rotary valve 9 is opened. After a set delay following the opening of the rotary valve 9, the vibrating screen 4 is started. During the startup phase, the flow regulating valve 17 is opened to the initial opening degree M.

[0052] like Figure 5As shown, during the conveying stage, the following methods are used to determine whether pipe blockage exists:

[0053] When the current rotational speed of rotary valve 9 is less than a multiple of its set rotational speed, a blockage is considered to exist. Specifically, the set multiple F should preferably be in the range of 1 > F > 0.7.

[0054] When the current internal pressure of the material conveying device is greater than the first pressure setting value P1, the vibrating screen 4 is stopped. If the current internal pressure of the material conveying device is less than the second pressure setting value P2 after the vibrating screen 4 is stopped, the vibrating screen 4 is started. If the current internal pressure of the material conveying device is greater than the third pressure setting value P3 after the vibrating screen 4 is stopped, it is determined that there is a pipe blockage. Among them, P3 > P1 > P2.

[0055] Additionally, when a buffer silo 6 and a level gauge 7 are installed, during the conveying stage, if the material level in the buffer silo 6 reaches the set level, the vibrating screen 4 will stop operating; when the material level in the buffer silo 6 drops below the set level, the vibrating screen 4 will restart. More specifically, the level gauge 7 can be connected to a higher position in the buffer silo 6. Thus, when the level gauge 7 has a level signal, it indicates that the material level in the buffer silo 6 has reached the set level; when the level gauge 7's level signal disappears, it indicates that the material level in the buffer silo 6 has dropped below the set level.

[0056] like Figure 6 As shown, during the automatic congestion clearing phase, automatic congestion clearing is achieved through the following methods:

[0057] First, close the rotary valve 9 and the intake valve 16, and reduce the opening of the flow regulating valve 17 from M to M3. The range of M3 should preferably be 0.8M > M > 0.3M.

[0058] In this way, when clearing blockages, because the opening of the flow regulating valve 17 is relatively small (the opening is M3, which is smaller than the initial opening M), the air intake valve 16 will open and allow a small amount of air to enter. The incoming air will flow along the gaps between the slice particles and slowly carry away the slice particles, thereby clearing blockages in the conveying pipe 20. This method is more effective and efficient than using a large amount of air to clear blockages, and it will not cause the material in the daily feed bin 21 to spray out from the daily feed bin exhaust port 22 due to excessive air intake.

[0059] The second step is to determine whether the current internal pressure of the material conveying device is less than the fourth pressure setting value P4. If so, the air inlet valve 16 is opened.

[0060] Third, if the current internal pressure of the material conveying device is less than the fourth pressure setting value P4 after opening the air inlet valve 16, then close the air inlet valve 16 to complete the unblocking process; if the current internal pressure of the material conveying device is greater than the fifth pressure setting value P5 after opening the air inlet valve 16, then close the air inlet valve 16 and return to the second step. Wherein, P3 > P5 > P1 > P2 > P4.

[0061] In addition, when pressure reducing valve 14 is provided, it controls the intake pressure to be adjusted to no more than 0.4 MPa during the start-up, delivery, and automatic unblocking phases. This ensures stable intake volume, avoids delivery instability caused by intake pressure fluctuations, and prevents damage to the sealing structure of rotary valve 9 and disruption of the clearance balance between the rotor and housing of rotary valve 9.

[0062] like Figure 7 As shown, during the shutdown phase, the vibrating screen 4 is shut down. If the current internal pressure of the material conveying device is less than the fourth pressure setting value P4 after the vibrating screen 4 is shut down, the rotary valve 9 is closed after a set delay time, and the opening of the flow regulating valve 17 is increased stepwise. After maintaining each opening setting time, the air inlet valve 16 is closed. Figure 7 In this process, the opening of the flow control valve 17 is adjusted twice. First, the opening of the flow control valve 17 is adjusted to M1. After intake time T4 at M1, the opening of the flow control valve 17 is then adjusted to M2. After intake time T5 at M2, the intake valve 16 is closed. Where M2 > M1 > M. More specifically, the range of M2 should ideally be M2 < 4M.

[0063] In this way, during the shutdown phase, residual slices (or other types of materials) in the conveying pipe 20 can be blown out by air intake, preventing cross-contamination caused by different types of slices during the next conveying. Moreover, when there are many residual slices, a larger air volume (flow regulating valve 17 opening M1) is used to purge the conveying pipe 20 to prevent the material in the pipe from forming long material plugs that would cause violent vibration in the conveying pipe 20. After most of the residual slices in the conveying pipe 20 have been blown into the daily material bin 21, the air volume is further increased (flow regulating valve 17 opening increased to M2) to purge the remaining small amount of slices, ensuring thorough cleaning.

[0064] The above examples illustrate the principles and implementation methods of this application. The descriptions of these embodiments are merely for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A method for operating a material conveying device, characterized in that, The material conveying device includes: a controller, a vibrating screen, a receiving device, a rotary valve connected between the inlet of the vibrating screen and the receiving device, a conveying pipe connected to the outlet of the receiving device, an air inlet pipe connected to the air inlet of the receiving device, an air inlet valve and a flow regulating valve connected to the air inlet pipe, and a pressure transmitter for detecting the internal pressure of the material conveying device. The controller is communicatively connected to the rotary valve, the inlet valve, the flow regulating valve, and the pressure transmitter, enabling the controller to determine whether there is a blockage based on the rotational speed of the rotary valve or the detection data of the pressure transmitter, and to automatically clear the blockage by controlling the rotary valve, the inlet valve, and the flow regulating valve when a blockage occurs. The operation method includes the following stages: first, the start-up stage is entered; after start-up, the conveying stage is entered; if a blockage occurs in the conveying stage, the automatic unblocking stage is entered; and after receiving a shutdown signal, the shutdown stage is entered. During the startup phase, the air intake valve is opened and the flow regulating valve is set to the initial opening M. After opening the air intake valve, the rotary valve is opened after a set delay. After opening the rotary valve, the vibrating screen is started after a set delay. During the conveying stage, the following methods are used to determine if there is any pipe blockage: When the current rotational speed of the rotary valve is less than a multiple of the set rotational speed of the rotary valve, it is determined that there is a blockage. When the current internal pressure of the material conveying device is greater than the first pressure setting value P1, the vibrating screen is stopped. If the current internal pressure of the material conveying device is less than the second pressure setting value P2 after the vibrating screen is stopped, the vibrating screen is started. If the current internal pressure of the material conveying device is greater than the third pressure setting value P3 after the vibrating screen is stopped, it is determined that there is a pipe blockage. During the automatic congestion clearing phase, automatic congestion clearing is achieved through the following methods: First, close the rotary valve and the intake valve, and adjust the opening of the flow regulating valve to M3; The second step is to determine whether the current internal pressure of the material conveying device is less than the fourth pressure setting value P4. If so, the air inlet valve is opened. Third, if the current internal pressure of the material conveying device after opening the air inlet valve is less than the fourth pressure setting value P4, then close the air inlet valve to complete the unblocking; if the current internal pressure of the material conveying device after opening the air inlet valve is greater than the fifth pressure setting value P5, then close the air inlet valve and return to the second step. Among them, M > M3, P3 > P5 > P1 > P2 > P4.

2. The method of operating the material conveying device according to claim 1, characterized in that, The material conveying device includes a buffer chamber, which is connected between the vibrating screen and the rotary valve. A level gauge is connected to the upper part of the buffer chamber, and the controller is communicatively connected to the level gauge so that the controller can control the vibrating screen to stop when the material level in the buffer chamber reaches a set value. During the conveying stage, the vibrating screen is stopped when the material level in the buffer bin reaches the set level, and is restarted when the material level in the buffer bin drops below the set level.

3. The method of operating the material conveying device according to claim 2, characterized in that, The vibrating screen is connected to the material silo and the buffer silo by expansion joints.

4. The method of operating the material conveying device according to claim 2, characterized in that, The rotary valve is equipped with a rotary valve exhaust pipe, the exhaust port of which is connected to the upper part of the buffer chamber. The upper part of the buffer chamber is equipped with a buffer chamber exhaust port. The connection position of the level gauge to the buffer chamber is lower than the connection position of the exhaust port of the rotary valve exhaust pipe to the buffer chamber.

5. The method of operating the material conveying device according to any one of claims 1-4, characterized in that, The material conveying device includes a pressure reducing valve connected to the air inlet pipe, and the controller is communicatively connected to the pressure reducing valve so that the controller can adjust the air inlet pressure by controlling the pressure reducing valve. During the startup, delivery, and automatic unblocking phases, the pressure reducing valve is controlled to adjust the intake pressure to no more than 0.4 MPa.

6. The method of operating the material conveying device according to any one of claims 1-4, characterized in that, The material conveying device includes a safety valve connected to the air inlet pipe, and a filter screen is provided between the safety valve and the air inlet pipe.

7. The method of operating the material conveying device according to any one of claims 1-4, characterized in that, During the shutdown phase, the vibrating screen is shut down. If the current internal pressure of the material conveying device is less than the fourth pressure setting value P4 after the vibrating screen is shut down, the rotary valve is closed after a set delay, and the opening of the flow regulating valve is increased stepwise. After maintaining each opening setting time, the air inlet valve is closed.

Images