Efficient filling device for polyester melt filter

Abstract

The utility model belongs to the technical field of polyester melt filtering, and particularly relates to an efficient filling device of a polyester melt filter, which comprises a melt three-way valve and a vacuumizing system, the melt three-way valve is provided with three connecting ports, one connecting port is connected with a melt conveying pipe I, and the other connecting port is connected with a melt conveying pipe II. One end, far away from the melt three-way valve, of the melt conveying pipe I is connected with an outlet of the melt filter, one end, far away from the melt three-way valve, of the melt conveying pipe II is connected with an inlet of the casting strip head, a control valve is mounted on the vacuum pipe, and one end, far away from the melt three-way valve, of the vacuum pipe is connected with a vacuumizing system. According to the utility model, the melt three-way valve is used for switching the pipeline communication path, and the vacuum-pumping system is used for forming negative pressure in the melt conveying pipe I and the melt filter, so that the negative pressure filling of the melt is realized, the melt filling efficiency is improved, the generation of bubbles is reduced, and the waste discharge amount of the melt is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of polyester melt filtration, and particularly relates to a high-efficiency filling device for a polyester melt filter. Background Art

[0002] During the production of polyester bottle flakes, the polyester melt undergoes meticulous filtration to ensure it meets high food-grade purity standards. To filter out all impurities from the melt, the melt filter requires extremely high density. Positive pressure applied by the melt pump pushes and squeezes the melt through the filter, thoroughly separating impurities. The filtered melt then passes through a strip casting head to produce ester strands, which are then pelletized in a pelletizer to produce transparent base flakes. As the production process continues, impurities gradually accumulate within the melt filter or at its front end. To assess the filter's condition, the pressure differential between the front and rear ends of the filter is typically monitored. A pressure differential exceeding 3 MPa indicates that the filter is clogged with impurities and requires cleaning. Under normal production conditions, the filter should be cleaned approximately every one to two months. To clean the filter, first close the six-way valve to prevent further melt from entering the filter. Then, drain any remaining melt from the pipe. Finally, use a hoist to remove the filter and replace it with a spare one.

[0003] After replacing the filter, melt filling is required. The traditional filling method is natural filling, and the natural filling process is often slow, usually lasting about 1 hour. According to statistical factory data, the natural filling duration is as short as 40 minutes and as long as 2 hours, and the filling efficiency is low. Moreover, if the melt filling effect is not good, bubbles may remain in the filter. These bubbles will cause the ester strips to be unstable during the subsequent pelletizing process, which will manifest as up and down jumping or bubbles inside the ester strips, causing the particles to be hollow. These unqualified slices cannot proceed to the next process and need to be continuously discharged until the bubbles are completely discharged before pelletizing. According to statistical factory data, the waste discharge under the natural filling method is at least 0.5 tons and at most 9 tons, which is a large amount of waste discharge. In summary, the natural filling method has the problems of low filling efficiency and large waste discharge losses. It is necessary to design a filling method to replace the natural filling method. Utility Model Content

[0004] The utility model aims to provide a high-efficiency filling device for a polyester melt filter, so as to solve the problems of low filling efficiency and large waste loss.

[0005] In order to achieve the above-mentioned purpose, the solution of the utility model is: a polyester melt filter high-efficiency filling device, including a melt three-way valve and a vacuum system, the melt three-way valve has three connecting ports, one of which is connected to a melt delivery pipe I, one is connected to a melt delivery pipe II, and the remaining connecting port is connected to a vacuum pipe, the end of the melt delivery pipe I away from the melt three-way valve is connected to the outlet of the melt filter, the end of the melt delivery pipe II away from the melt three-way valve is connected to the inlet of the casting head, a control valve is installed on the vacuum pipe, and the end of the vacuum pipe away from the melt three-way valve is connected to the vacuum system.

[0006] The working principle and beneficial effects of this solution are as follows: in this solution, a melt three-way valve is used to switch the pipeline connection path, so that after the melt filter is replaced, the melt delivery pipeline I is connected to the vacuum tube, and a vacuum system is used to form a negative pressure in the melt delivery pipeline I and the melt filter, thereby realizing negative pressure filling of the melt, greatly reducing the generation of bubbles, reducing the amount of melt waste, and improving the melt filling efficiency.

[0007] Optionally, the melt conveying pipe I is provided with a pressure sensor for detecting the pressure inside the pipe, and the pressure sensor is connected to the control valve signal.

[0008] In this solution, the detection end of the pressure sensor is located near the top wall of the melt conveying pipe I. When the melt fills the melt filter, the pressure sensor will detect the pressure signal exerted by the melt on it, the control valve will automatically close, and the vacuum tube will be cut off in time through the melt three-way valve to prevent the melt from flowing into the vacuum system.

[0009] Optionally, a vacuum gauge is installed on the vacuum tube.

[0010] In this solution, a vacuum meter is used to display the vacuum degree in the vacuum tube and the melt delivery tube I to ensure that the vacuum degree is within a preset range.

[0011] Optionally, the vacuum pumping system is a vacuum pump.

[0012] In this solution, a vacuum pump is used to form negative pressure in the melt conveying pipe I.

[0013] Optionally, the vacuum pumping system is a final polycondensation vacuum pumping system.

[0014] In this solution, the final polycondensation vacuum system is used to achieve negative pressure formation in the melt conveying pipe I, avoiding the need for adding a vacuum pump and reducing equipment costs.

[0015] Optionally, the vacuum tube is provided with an air pressure sensor for detecting the air pressure in the tube, and the air pressure sensor is connected to the control valve signal.

[0016] In this solution, an air pressure sensor is used to detect the air pressure in the vacuum tube. When the air pressure in the vacuum tube reaches a preset value, the control valve is automatically closed and the vacuum pumping stops.

[0017] Optionally, a heat medium insulation jacket is provided outside the vacuum tube.

[0018] In this solution, during the melt filling process, even if a small amount of melt is extracted by the vacuum system, the melt will be quickly condensed and collected when it enters the scraper condenser of the final polycondensation vacuum system, ensuring the continuity and stability of the production process. The heat medium insulation jacket outside the vacuum tube can prevent the melt inside the tube from condensing and clogging the vacuum tube.

[0019] Optionally, the melt three-way valve is located at the highest point of the pipeline between the melt filter and the strip casting head.

[0020] In this solution, the melt three-way valve is located at the highest point of the pipeline between the melt filter and the casting head, thereby ensuring that the melt does not immediately enter the melt three-way valve after passing through the melt filter, thereby ensuring that vacuum can be continuously drawn during the process of the melt filling the melt filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic structural diagram of a high-efficiency filling device for a polyester melt filter in Example 1 of the present utility model;

[0022] Figure 2 This is a schematic structural diagram of a high-efficiency filling device for a polyester melt filter in Example 2 of the present utility model;

[0023] Figure 3 This is a schematic structural diagram of a high-efficiency filling device for a polyester melt filter in Example 3 of the present utility model;

[0024] Figure 4 This is a structural schematic diagram of a high-efficiency filling device for a polyester melt filter in Example 4 of the present utility model. DETAILED DESCRIPTION

[0025] The following is further described in detail through specific implementation methods:

[0026] The symbols in the drawings of the specification include: melt three-way valve 1, melt delivery pipe I2, melt delivery pipe II3, vacuum tube 4, melt filter 5, strip casting head 6, control valve 7, vacuum gauge 8, vacuum pump 9, final polycondensation reactor 10, melt pump 11, melt six-way valve 12, air pressure sensor 13, final polycondensation vacuum system 14, and pressure sensor 15.

[0027] Example 1

[0028] This embodiment is basically as Figure 1The figure shows a high-efficiency filling device for a polyester melt filter, comprising a melt three-way valve 1 and a vacuum system. The melt three-way valve 1 has three connections, one of which is connected to a melt delivery pipe I2, one to a melt delivery pipe II3, and the remaining to a vacuum pipe 4. The end of the melt delivery pipe I2, away from the melt three-way valve 1, is connected to the outlet of the melt filter 5. The end of the melt delivery pipe II3, away from the melt three-way valve 1, is connected to the inlet of the strip casting head 6. The vacuum pipe 4 is equipped with a control valve 7 and a vacuum gauge 8. The end of the vacuum pipe 4, away from the melt three-way valve 1, is connected to the vacuum system. In this embodiment, the vacuum system is a vacuum pump 9. In addition, the melt three-way valve 1 is located at the highest point of the pipeline between the melt filter 5 and the strip casting head 6.

[0029] In actual use, under normal operating conditions, the melt three-way valve 1 connects the melt delivery pipe I2 and the melt delivery pipe II3, and the vacuum pipe 4 is disconnected from the melt delivery pipe I2 and the melt delivery pipe II3. Under the action of the melt pump 11, the melt in the final polycondensation reactor 10 is filtered by the melt filter 5 and then enters the strip casting head 6. When the melt filter 5 needs to be replaced, the channel corresponding to the melt six-way valve 12 is first closed (the melt six-way valve 12 can independently control the connection and disconnection of the pipelines between the six melt filters 5 and the melt six-way valve 12) so that no more melt enters the pipeline where the melt filter 5 to be replaced is located. Then, the remaining melt in the pipeline where the melt filter 5 to be replaced is drained (the melt is discharged through the drain pipe, which is not shown). Next, the melt filter 5 is replaced using lifting equipment. After replacement, the melt three-way valve 1 is switched so that the melt delivery pipe I2 is connected to the vacuum pipe 4 (the direction of the melt delivery pipe II3 is cut off). The vacuum pump 9 is started and begins to evacuate until the reading on the vacuum gauge 8 is within the range of 160-200 Pa (i.e., the absolute pressure in the melt conveying pipe Ⅰ2 is 160-200 Pa. The pressure range here is only an example. In actual application, other pressure ranges may be selected according to the on-site working conditions, such as 500 Pa). Then, the control valve 7 is closed, and then the vacuum pump 9 is closed to stop the evacuation work.

[0030] Next, the melt three-way valve 1 is switched, reconnecting the melt delivery pipe I2 and melt delivery pipe II3. The vacuum pipe 4 is disconnected from both melt delivery pipes I2 and II3. The corresponding channel of the melt six-way valve 12 is then opened, unblocking the pipeline where the melt filter 5 is replaced. The melt enters the negative pressure melt filter 5, thus achieving negative pressure filling of the melt. During the melt filling process, the melt flows through the melt three-way valve 1 into the melt delivery pipe II3 and continues to flow into the strip casting head 6.

[0031] To sum up, in this embodiment, before the melt is filled, the vacuum pump 9 is used to extract the air in the pipeline between the melt six-way valve 12 and the melt filter 5, the air in the melt filter 5, and the air in the melt delivery pipe Ⅰ2 to form a negative pressure state, thereby realizing negative pressure filling of the melt, improving the melt filling efficiency, reducing the generation of bubbles, and reducing the amount of melt waste.

[0032] Example 2

[0033] The difference between this embodiment and the first embodiment is that: Figure 2 As shown, in this embodiment, a pressure sensor 13 is provided on the vacuum tube 4 for detecting the air pressure within the tube. Pressure sensor 13 is electrically connected to the control valve 7, and the model of pressure sensor 13 is MIK-P300. Thus, pressure sensor 13 detects the air pressure within the vacuum tube 4. When the air pressure within the vacuum tube 4 drops to 200 Pa, control valve 7 automatically closes, eliminating the need for manual closing of control valve 7 and improving the automation level of the device.

[0034] Example 3

[0035] The difference between this embodiment and the first embodiment is that: Figure 3 As shown, the vacuum pumping system in this embodiment is a final polycondensation vacuum pumping system 14 .

[0036] In this embodiment, the existing final polycondensation vacuum system 14 in the polyester production line is used as the power source for generating negative pressure, thereby avoiding the need for a new vacuum pump 9 and reducing equipment costs.

[0037] Example 4

[0038] The difference between this embodiment and the third embodiment is that: Figure 4 As shown, in this embodiment, melt delivery pipe I 2 is equipped with a pressure sensor 15 for detecting the hydraulic pressure within the pipe. Pressure sensor 15 is electrically connected to control valve 7. Pressure sensor 15 is model BRW800-2300, and the detection end of pressure sensor 15 is located near the top wall of melt delivery pipe I. A heat medium insulation jacket (not shown) is provided outside the vacuum tube 4 to prevent condensation of the melt within the pipe.

[0039] In this embodiment, after the melt filter 5 is replaced, the melt three-way valve 1 is switched to connect the vacuum tube 4 with the melt delivery tube I2. The control valve 7 on the vacuum tube 4 is opened, and the final polycondensation vacuum system 14 is used to evacuate the melt filter 5, creating a negative pressure of 160-200 Pa. Subsequently, the channel corresponding to the melt six-way valve 12 is opened, and the melt fills the melt filter 5 under negative pressure, with some of the melt flowing through the melt filter 5 into the melt delivery tube I2. During this process, the pressure sensor 15 detects whether the melt in the melt delivery tube I2 exerts pressure on it. If the pressure sensor 15 detects that the melt exerts pressure on it, it indicates that the melt in the melt delivery tube I has filled the portion of the melt delivery tube I2 where the pressure sensor 15 is located, indicating that the melt filter 5 has completed the filling process. The control valve 7 then automatically closes, thereby preventing the melt from flowing into the vacuum tube 4. At the same time, the melt three-way valve 1 is switched so that the melt delivery pipe I2 and the melt delivery pipe II3 are reconnected, the vacuum tube 4 and the melt delivery pipe I2 and the melt delivery pipe II3 are in a cut-off state, and the melt flows into the casting head 6 through the melt delivery pipe II3.

[0040] During the process of the melt filling the melt filter 5, vacuuming is continuously performed, so that a small amount of melt is drawn into the vacuum tube 4 and enters the final polycondensation vacuum system 14, and is condensed and collected by the scraper condenser in the final polycondensation vacuum system 14, thereby ensuring the continuity and stability of the production process. The heat medium insulation jacket outside the vacuum tube 4 can prevent the melt in the tube from condensing and clogging the vacuum tube 4.

[0041] In summary, this embodiment enables continuous vacuuming during the process of melt filling melt filter 5, thereby further improving melt filling efficiency. Furthermore, control valve 7 on vacuum tube 4 can automatically close, improving the automation level of the device. Furthermore, during the continuous vacuuming process, the melt drawn into final polycondensation vacuuming system 14 is condensed and collected by the scraper condenser, without causing damage to the vacuuming system.

[0042] The above description is merely an embodiment of the present invention. Commonly known details such as the specific structure and characteristics of the solution are not described in detail here. It should be noted that those skilled in the art may make various modifications and improvements without departing from the structure of the present invention. These modifications and improvements should also be considered within the scope of protection of the present invention and will not affect the effectiveness and practicality of the implementation of the present invention. The specific embodiments and other descriptions in the specification may be used to interpret the content of the claims.

Claims

1. A polyester melt filter high-efficiency filling device, characterized by: It includes a melt three-way valve and a vacuum pumping system. The melt three-way valve has three connecting ports, one of which is connected to a melt conveying pipe I, one is connected to a melt conveying pipe II, and the remaining is connected to a vacuum pipe. The end of the melt conveying pipe I away from the melt three-way valve is connected to the outlet of the melt filter, the end of the melt conveying pipe II away from the melt three-way valve is connected to the inlet of the casting head, a control valve is installed on the vacuum pipe, and the end of the vacuum pipe away from the melt three-way valve is connected to the vacuum pumping system.

2. The polyester melt filter high-efficiency filling device according to claim 1, characterized in that: The melt conveying pipe is provided with a pressure sensor for detecting the pressure inside the pipe, and the pressure sensor is connected to the control valve signal.

3. The polyester melt filter high-efficiency filling device according to claim 1, characterized in that: A vacuum gauge is installed on the vacuum tube.

4. The polyester melt filter high-efficiency filling device according to claim 1 or 2, characterized in that: The vacuum pumping system is a vacuum pump.

5. The polyester melt filter high-efficiency filling device according to claim 1 or 2, characterized in that: The vacuum pumping system is a final polycondensation vacuum pumping system.

6. The polyester melt filter high-efficiency filling device according to claim 4, characterized in that: The vacuum tube is provided with an air pressure sensor for detecting the air pressure in the tube, and the air pressure sensor is connected to the control valve signal.

7. The polyester melt filter high-efficiency filling device according to claim 5, characterized in that: A heat medium insulation jacket is provided outside the vacuum tube.

8. The polyester melt filter high-efficiency filling device according to claim 1, characterized in that: The melt three-way valve is located at the highest point of the pipeline between the melt filter and the strip casting head.

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