A foaming apparatus based on pulp fiber foam density control
By monitoring foam density in real time and dynamically adjusting the speed of the foaming machine, the problems of rough control of the foaming process and severe pulp stratification in chemical foaming equipment have been solved, achieving precise control of pulp fiber foam and improving the production efficiency and product quality of paper-based materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHINA HAISUM ENG
- Filing Date
- 2025-06-23
- Publication Date
- 2026-07-07
AI Technical Summary
Existing chemical foaming equipment suffers from problems such as poor control of the foaming process, insufficient stability, and severe pulp foam stratification, which affect the continuous production of paper-based materials.
By monitoring the foam density in real time and dynamically adjusting the speed of the foaming machine, and combining the foaming machine, the conveying pump and the density measuring device, a foaming-conveying-measuring-conveying cycle system is formed to achieve precise control of the foam density of pulp fibers.
It improves the production efficiency and product quality of paper-based materials, avoids insufficient or excessive foaming, reduces the stratification of fiber foam during pipeline transportation, and ensures the continuous production of paper-based materials.
Smart Images
Figure CN224462564U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a foaming device based on pulp fiber foam density control, belonging to the technical field of pulp foaming equipment. Background Technology
[0002] In recent years, with the continuous advancement of environmental protection policies, the use of traditional petroleum-based plastics has been strictly restricted, and the market demand for environmentally friendly materials has continued to rise. Paper-based materials, with their renewable and biodegradable properties, have been widely used in many fields, such as packaging, construction, automobiles, and electronics, and are gradually becoming a popular alternative to traditional plastics, demonstrating broad development prospects.
[0003] In the preparation process of paper-based materials, chemical foaming has gradually become the mainstream method due to its significant advantages in terms of condition control, temperature and pressure requirements, and equipment investment. Chemical foaming can produce paper-based materials with specific cell structures and excellent mechanical properties to meet the needs of different application scenarios.
[0004] The foaming process of plant fibers is a crucial step in the preparation of paper-based materials, and its quality directly determines the mechanical properties of the paper-based materials. The stability of the fiber foam has a significant impact on the material density and performance of the final product. Foam half-life is a commonly used method to measure foam stability. Generally speaking, fiber foam has a short half-life, which requires molding and drying to be completed in a very short time to ensure the quality of the final product.
[0005] The existing chemical foaming preparation equipment and processes have the following main drawbacks:
[0006] The foaming process is poorly controlled and lacks stability: Existing technologies mainly regulate the foaming process by controlling the foaming rate (foaming ratio), but this method is relatively crude, makes it difficult to guarantee the stability of the foam, and is easily affected by changes in raw materials and production parameters, resulting in insufficient or excessive foaming, which is not conducive to continuous industrial production.
[0007] Severe pulp foam stratification: In continuous production processes, pulp foam is prone to stratification during pipeline transportation, affecting the structural properties of the paper base material. Foam stratification leads to an increased drainage rate, further shortening the foam stabilization time and reducing the mechanical properties of the paper base material.
[0008] Therefore, there is an urgent need in this field for a foaming device based on pulp fiber foam density control to overcome the shortcomings of existing chemical foaming preparation equipment. Utility Model Content
[0009] The technical problem this invention aims to solve is how to accurately control pulp foam during continuous production.
[0010] To address the aforementioned technical problems, this invention provides a foaming device based on pulp fiber foam density control. By monitoring the foam density in real time and dynamically adjusting the speed of the foaming machine according to the density signal, precise control of pulp fiber foam density is achieved, thereby improving the production efficiency and product quality of paper-based materials and providing a feasible control strategy for the continuous production of paper-based materials.
[0011] To achieve the above-mentioned technical objectives and effects, this application provides the following technical solution:
[0012] A foaming device based on pulp fiber foam density control includes a foaming machine, a conveying pump, and a density measuring device. The foaming machine serves as the carrier for the pulp fiber foaming process. The conveying pump connects the foaming machine, the density measuring device, and the next stage. The conveying pump passes a portion of the pulp fiber foam from the foaming machine into the density measuring device for online density detection of the foamed fiber foam. If the density is within acceptable limits, the conveying pump pumps the remaining pulp fiber foam from the foaming machine to the next stage.
[0013] The foaming machine includes a foaming tank, a stirrer, a motor, a frequency converter, and a control unit. The stirrer is located inside the foaming tank and is driven by the motor. The frequency converter is electrically connected to both the motor and the control unit and is used to control the speed of the motor. The control unit is electrically connected to the density measuring device and is used to feed back density measurement data to the control unit. The control unit controls the stirring speed of the motor driven by the frequency converter based on the fed-back density data.
[0014] Preferably, the foaming barrel has a discharge port at the bottom and multiple return ports are evenly distributed on the outer periphery of the foaming barrel near the top, and each return port is connected to an electric valve.
[0015] Furthermore, the inlet of the conveying pump is connected to the outlet at the bottom of the foaming tank, and the outlet of the conveying pump is connected to the density measuring device, the multiple return ports at the top of the foaming tank, and the next section through independent pipelines and control valves installed on the independent pipelines.
[0016] Furthermore, the density measuring device includes a measuring module for online density detection of foamed fiber foam. The measuring module includes a feed valve, a measuring tank, a drain valve, a drain pipe, and a weighing module. The feed end of the feed valve is connected to the independent pipeline corresponding to the outlet end of the delivery pump. The top of the measuring tank is provided with a measuring inlet, and the discharge end of the feed valve is connected to the measuring inlet. A drain outlet is provided at the center of the bottom of the measuring tank, and the drain outlet is connected to the inlet end of the drain valve. The bottom edge of the measuring tank is connected to the weighing module by a connecting rod. The weighing module is placed on a flat platform, and the outlet end of the drain valve is connected to the drain pipe.
[0017] Furthermore, the discharge end of the feed valve is positioned above the measuring inlet of the measuring tank and does not contact the measuring tank.
[0018] Furthermore, the outlet end of the drain valve is connected to the drain pipe in a non-contact manner.
[0019] Furthermore, the inner diameter of the drain pipe is 1.5 to 3 times the inner diameter of the drain valve.
[0020] Furthermore, the density measuring device also includes a rinsing module for online cleaning of the measuring module after the measurement is completed. The rinsing module includes a rinsing water pipe, a rinsing water valve, a spray head, and a fan. The spray head is located at the center of the upper part of the measuring tank. The spray head is connected to the rinsing water pipe through the rinsing water valve. The rinsing water pipe is also connected to an external water supply device to supply rinsing water at a constant pressure to the spray head. The fan is located at the top of the measuring tank to blow air into the inner cavity of the measuring tank.
[0021] Furthermore, the discharge end of the conveying pump is closely connected to the density measuring device.
[0022] Preferably, the delivery pump includes, but is not limited to, positive displacement pumps, such as gear pumps, screw pumps, or diaphragm pumps.
[0023] The foaming device based on pulp fiber foam density control provided by this utility model has the following advantages:
[0024] 1. The foaming equipment based on pulp fiber foam density control of this utility model organically combines a foaming machine, a conveying pump, and a density measuring device to form a "foaming-conveying-measuring-conveying" cycle system; it realizes precise control of the foaming process of pulp fiber in the foaming machine, adjusts the speed of the foaming machine in a timely manner according to the foaming density value during production, realizes visualization of the foaming process, successfully avoids the problem of insufficient or excessive foaming, and ensures that the final product meets the predetermined quality standards.
[0025] 2. This invention installs a density measuring device adjacent to the inlet of the conveying pump to the next stage, enabling real-time detection of the pulp fiber foam density at the pump outlet. This effectively reduces the impact of stratification and foam collapse during fiber foam transport in the pipeline, ensuring that the measured value is essentially the same as the actual value at the next stage. This facilitates precise control of the pulp fiber foaming process, and is particularly significant for the continuous production of pulp fiber paper-based materials. Attached Figure Description
[0026] Figure 1 A schematic diagram of the structure of a foaming device based on pulp fiber foam density control provided for an embodiment of this utility model;
[0027] Figure 2 A schematic diagram of the foaming process of a foaming device based on pulp fiber foam density control provided for an embodiment of this utility model.
[0028] In the picture:
[0029] 1-Foaming machine; 11-Foaming tank; 111-Discharge port; 112-Return port; 12-Agitator; 13-Motor; 14-Frequency converter; 15-Control unit; 2-Transfer pump; 3-Density measuring device; 31-Measuring module; 311-Feed valve; 312-Measuring tank; 3121-Measuring inlet; 3122-Drain outlet; 313-Drain valve; 314-Drain pipe; 315-Weighing module; 32-Rinsing module; 321-Rinsing water pipe; 322-Rinsing water valve; 323-Spray head; 324-Fan. Detailed Implementation
[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0031] Reference Figure 1 and Figure 2 A foaming device based on pulp fiber foam density control includes a foaming machine 1, a conveying pump 2, and a density measuring device 3. The foaming machine 1 is the carrier of the pulp fiber foaming process. The conveying pump 2 is used to connect the foaming machine 1, the density measuring device 3, and the next process. Through the conveying pump 2, part of the pulp fiber foam in the foaming machine 1 can be passed into the density measuring device 3 for online density detection of the foamed fiber foam. If the density is qualified, the conveying pump 2 pumps the remaining pulp fiber foam from the foaming machine 1 to the next process.
[0032] Reference Figure 1The foaming machine 1 includes a foaming tank 11, a stirrer 12, a motor 13, a frequency converter 14, and a control unit 15.
[0033] The stirrer 12 is installed inside the foaming tank 11 and driven by the motor 13. In feasible embodiments, the control unit 15 can be a PLC control module or an MCU controller. In this embodiment, the control unit 15 is preferably a PLC controller. The frequency converter 14 is electrically connected to the motor 13 and the control unit 15 through wiring terminals. The frequency converter 14 is used to control the speed of the motor 13. The control unit 15 is electrically connected to the density measuring device 3. The density measuring device 3 is used to feed back the density measurement data to the control unit 15. The control unit 15 has a preset target density value for the pulp fiber foam molding process. The control unit 15 controls the flow according to the fed-back density data. The inverter 14 drives the stirring speed of the motor 13. When the measured density is lower than the target density value, it indicates that the foaming is excessive. The control unit 15 controls the foaming machine 1 to reduce the frequency of the inverter 14 and reduce the speed of the motor 13 driving the stirrer 12 to continue running. When the measured density is higher than the target density value, it indicates that the foaming is insufficient. The control unit 15 controls the frequency of the inverter 14 of the foaming machine 1 and increases the speed of the stirrer 12 of the foaming machine 1, so that the pulp fibers in the foaming tank 11 can continue to foam and expand in volume. The target value preset of the PLC and the linkage control between the stirrer 12, the motor 13, the inverter 14 and the control unit 15 are existing technologies and will not be described in detail.
[0034] Reference Figure 1 The bottom of the foaming tank 11 is integrally formed with a discharge port 111. A control valve is installed at the discharge port 111 to control its opening and closing. Multiple return ports 112 are evenly distributed on the outer wall of the foaming tank 11 near the top. The multiple return ports 112 are symmetrically arranged, and each return port 112 is connected to an electric valve to control the opening and closing of the return port 112.
[0035] Furthermore, the inlet of the conveying pump 2 is connected to the outlet 111 at the bottom of the foaming tank 11. The outlet 111 of the conveying pump 2 is connected to the density measuring device 3, multiple return ports 112 on the upper part of the foaming tank 11, and the next stage equipment through independent pipelines and control valves installed on the independent pipelines. The next stage equipment can be a drying device, which will be further determined according to the preparation process and will not be elaborated in detail. The outlet of the conveying pump 2 is connected to the density measuring device 3 as closely as possible so that the measured fiber foam density value is consistent with the density value conveyed to the next stage, ensuring the accuracy and reliability of the measurement value.
[0036] The transfer pump 2 includes, but is not limited to, positive displacement pumps, such as gear pumps, screw pumps, or diaphragm pumps. Power pumps (such as centrifugal pumps) must not be used to reduce the impact of centrifugal force generated by the transfer pump 2 on the pulp fiber foam during the transfer process, which may cause the pulp fiber foam to break or delaminate, resulting in the pulp fiber foam foam quality failing to meet the requirements of the next stage.
[0037] Reference Figure 1 The density measuring device 3 includes a measuring module 31 for online density detection of foamed fiber foam.
[0038] The measuring module 31 includes a feed valve 311, a measuring tank 312, a drain valve 313, a drain pipe 314, and a weighing module 315. The feed end of the feed valve 311 is connected to an independent pipeline corresponding to the outlet end of the conveying pump 2. The top of the measuring tank 312 has a measuring inlet 3121, and the discharge end of the feed valve 311 is connected to the measuring inlet 3121. The bottom center of the measuring tank 312 has a drain port 3122, which is connected to the inlet end of the drain valve 313. The bottom edge of the measuring tank 312 is connected to the weighing module 315 by a connecting rod. The weighing module 315 is placed on a flat platform. The outlet end of the drain valve 313 is connected to the drain pipe 314, and the inner diameter of the drain pipe 314 is 1.5 to 3 times the inner diameter of the drain valve 313. Specifically, the discharge end of the feed valve 311 is located above the measuring inlet 3121 of the measuring tank 312 and does not contact the measuring tank 312. The outlet end of the drain valve 313 is connected to the drain pipe 314 in a non-contact manner. That is, the discharge of the feed valve 311 and the discharge of the drain valve 313 can both be done by spraying. The weighing module 315 can be a conventional weighing scale.
[0039] The foam density of measuring tank 312 is measured as follows: the delivery pump 2 is fixed for a fixed time, the volume of pulp fiber foam injected each time is constant, the weight is measured by weighing, and the foam density can be obtained by M / V, where M is the weight increase of measuring tank 312 after the pulp fiber foam is injected, and V is the volume of pulp fiber foam injected.
[0040] Reference Figure 1 The density measuring device 3 also includes a rinsing module 32 for online cleaning of the measuring module 31 after the measurement is completed, so that the density can be measured again next time.
[0041] The rinsing module 32 includes a rinsing water pipe 321, a rinsing water valve 322, a spray head 323, and a blower 324. The spray head 323 is arranged at the center of the upper part of the measuring tank 312. The spray head 323 is connected to the rinsing water pipe 321 through the rinsing water valve 322. The spray rinsing process is controlled by the opening and closing of the rinsing water valve 322. The rinsing water pipe 321 is also connected to an external water supply device to supply rinsing water at a constant pressure to the spray head 323. The blower 324 is installed on the top of the measuring tank 312 to blow dry air into the inner cavity of the measuring tank 312 to achieve air drying.
[0042] The method of using the foaming equipment based on pulp fiber foam density control according to this utility model is as follows:
[0043] Step 1: Put a certain concentration of wood pulp fiber into the foaming tank 11, adjust the speed of the agitator 12 of the foaming machine 1, and use a higher speed to quickly mix the wood pulp fiber. After 2 to 6 minutes, reduce the speed of the agitator 12 to run at a low speed. At the same time, add the foaming agent according to the ratio and keep running at a low speed for 1 to 5 minutes. The purpose is to make the foaming agent and wood pulp fiber evenly mixed.
[0044] Taking the addition of 45 kg of 4.5% wt pulp fiber to foaming tank 11 as an example, adjust the speed of agitator 12 of foaming machine 1 to quickly mix the wood pulp fiber at 800 RPM. After 2 minutes, reduce the speed of agitator 12 to 200 RPM. At the same time, add 1 L of 4% wt foaming agent according to the ratio. Keep the foaming machine running at 1200 RPM for 1 minute to allow the foaming agent to mix evenly with the pulp fiber.
[0045] Step 2: Increase the rotation speed of the agitator 12 of the foaming machine 1 and run it at high speed for 1 to 5 minutes. After the wood pulp fiber foam expands in volume, open the control valve of the discharge port 111 at the bottom of the foaming tank 11 and the electric valve of the return port 112 around the top of the foaming tank 11. Turn on the delivery pump 2 and use the operation of the delivery pump 2 to make the pulp fiber foam circulate in the pipeline between the foaming tank 11 and the delivery pump 2. The delivery pump 2 runs in circulation for 1 to 4 minutes. After the time is up, proceed to step 3.
[0046] After the mixing time of 45kg of 4.5%wt pulp fiber is completed, increase the speed of the agitator 12 of the foaming machine 1 to 600RPM and run it at high speed for 4 minutes. Open the control valve of the bottom discharge port 111 of the foaming tank 11 and the electric valve of the return port 112 around the top of the foaming tank 11. Turn on the delivery pump 2 and use the operation of the delivery pump 2 to make the pulp fiber foam circulate in the pipeline between the foaming tank 11 and the delivery pump 2. After the delivery pump 2 runs for 1 minute, proceed to the third step.
[0047] Step 3: Open the feed valve 311 of the density measuring device 3 (controlled by a three-way valve, at which time the foam does not enter the foaming tank 11), and close it after 5-30 seconds (after closing, the foam flows back into the foaming tank 11); the volume of pulp fiber foam injected each time can be obtained according to the flow rate of the delivery pump 2. The weighing module 315 transmits the measured weight value to the control unit 15, which provides the measured density value of the pulp fiber foam in real time and compares it with the target density value. If the measured density value is higher than the setting value of the subsequent molding process (target density value), the control unit 15 controls the frequency of the inverter 14 of the foaming machine 1 and increases the speed of the agitator 12 of the foaming machine 1, allowing the pulp fiber in the foaming tank 11 to continue to foam and expand in volume; if the measured density value is lower than the setting value of the subsequent molding process, it indicates that the foaming is over-foamed, and the control unit 15 controls the frequency of the inverter 14 of the foaming machine 1 to decrease the speed of the agitator 12 and continue to run. If the measured density meets the requirements of the subsequent molding process, open the valve of the discharge port 111 of the conveying pump 2 to the next section and output qualified pulp fiber foam.
[0048] Taking the addition of 45 kg of 4.5% wt pulp fiber to foaming tank 11 as an example, the feed valve 311 of density measuring device 3 is opened and closed after 10 seconds (after closing, the foam flows back into foaming tank 11); the volume of pulp fiber foam in measuring tank 312 is 1L, and weighing module 315 transmits the measured weight value to control unit 15. Control unit 15 gives the measured density value of pulp fiber foam in real time as 500 g / L, which is lower than the setting value of subsequent molding process (650 ± 30 g / L). Control unit 15 controls the frequency of inverter 14 of foaming machine 1 and adjusts the speed of agitator 12 of foaming machine 1 to 400 RPM, so that the foaming rate of pulp fiber in foaming tank 11 is reduced.
[0049] Step 4: After the density measuring device 3 completes the density measurement in Step 3 above, immediately open the drain valve 313 at the bottom of the measuring tank 312 to remove the fiber foam inside the tank. Then, open the flushing water valve 322 at the top of the measuring tank 312 to spray water around the inner cavity of the tank and clean the measuring tank 312. Spray for 10-40 seconds, and close the flushing water valve 322 after spraying. Turn on the blower 324 at the top of the measuring tank 312 to blow dry the tank wall from top to bottom for 10-30 seconds. After the drying time is over, turn off the blower 324 and the drain valve 313 of the measuring tank 312 in sequence, and wait for the next measurement.
[0050] Step 5: Reduce the rotation speed to 400 RPM and run for 3 minutes as described in Step 3. Then repeat the online density measurement step in Step 3. The control unit 15 outputs a pulp fiber foam density value of 630 g / L, which meets the material requirements for the next stage. Immediately open the control valve of the conveying pump 2 to discharge the qualified pulp fiber foam to the next stage. At the same time, clean the density measuring device 3 after this measurement as described in Step 4.
[0051] The above description is merely a preferred embodiment of this utility model and is not intended to limit this utility model in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from this utility model, and these improvements and additions should also be considered within the protection scope of this utility model. Any modifications, alterations, and equivalent changes made by those skilled in the art without departing from the spirit and scope of this utility model using the disclosed technical content are equivalent embodiments of this utility model. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of this utility model are still within the scope of the technical solution of this utility model.
Claims
1. A foaming device based on pulp fiber foam density control, characterized in that, Includes a foaming machine (1), a conveying pump (2), and a density measuring device (3). The foaming machine (1) is the carrier for the pulp fiber foaming process. The conveying pump (2) is used to connect the foaming machine (1), the density measuring device (3), and the next process. The conveying pump (2) passes some of the pulp fiber foam in the foaming machine (1) into the density measuring device (3) for online density detection of the foamed fiber foam. If the density is qualified, the conveying pump (2) pumps the remaining pulp fiber foam from the foaming machine (1) to the next process. The foaming machine (1) includes a foaming tank (11), a stirrer (12), a motor (13), a frequency converter (14), and a control unit (15). The stirrer (12) is located inside the foaming tank (11) and driven by the motor (13). The frequency converter (14) is electrically connected to the motor (13) and the control unit (15) respectively. The frequency converter (14) is used to control the speed of the motor (13). The control unit (15) is electrically connected to the density measuring device (3). The density measuring device (3) is used to feed back the density measurement data to the control unit (15). The control unit (15) controls the frequency converter (14) to drive the stirring speed of the motor (13) according to the fed-back density data.
2. The foaming equipment based on pulp fiber foam density control as described in claim 1, characterized in that, The foaming barrel (11) has a discharge port (111) at the bottom and a plurality of return ports (112) are evenly distributed on the outer wall of the periphery near the top of the foaming barrel (11). Each of the return ports (112) is connected to an electric valve.
3. The foaming equipment based on pulp fiber foam density control as described in claim 2, characterized in that, The inlet of the conveying pump (2) is connected to the outlet (111) at the bottom of the foaming barrel (11). The outlet (111) of the conveying pump (2) is connected to the density measuring device (3), the multiple return ports (112) at the top of the foaming barrel (11), and the next section through independent pipelines and control valves installed on the independent pipelines.
4. The foaming equipment based on pulp fiber foam density control as described in claim 3, characterized in that, The density measuring device (3) includes a measuring module (31) for online density detection of foamed fiber foam. The measuring module (31) includes a feed valve (311), a measuring tank (312), a drain valve (313), a drain pipe (314), and a weighing module (315). The feed end of the feed valve (311) is connected to the independent pipeline corresponding to the outlet end of the conveying pump (2). The top of the measuring tank (312) is provided with a measuring inlet (315). 21) The discharge end of the feed valve (311) is connected to the measuring inlet (3121). A drain port (3122) is provided at the center of the bottom of the measuring tank (312). The drain port (3122) is connected to the inlet end of the drain valve (313). The bottom edge of the measuring tank (312) is connected to the weighing module (315) by a connecting rod. The weighing module (315) is placed on a flat platform. The outlet end of the drain valve (313) is connected to the drain pipe (314).
5. The foaming equipment based on pulp fiber foam density control as described in claim 4, characterized in that, The discharge end of the feed valve (311) is located above the measuring inlet (3121) of the measuring tank (312) and does not contact the measuring tank (312).
6. The foaming equipment based on pulp fiber foam density control as described in claim 4, characterized in that, The outlet end of the drain valve (313) is connected to the drain pipe (314) in a non-contact manner.
7. A foaming device based on pulp fiber foam density control as described in claim 4, characterized in that, The inner diameter of the drain pipe (314) is 1.5 to 3 times the inner diameter of the drain valve (313).
8. The foaming equipment based on pulp fiber foam density control as described in claim 4, characterized in that, The density measuring device (3) further includes a rinsing module (32) for online cleaning of the measuring module (31) after the measurement is completed. The rinsing module (32) includes a rinsing water pipe (321), a rinsing water valve (322), a spray head (323), and a fan (324). The spray head (323) is located at the upper center of the measuring tank (312). The spray head (323) is connected to the rinsing water pipe (321) through the rinsing water valve (322). The rinsing water pipe (321) is also connected to an external water supply device to supply rinsing water at a constant pressure to the spray head (323). The fan (324) is located at the top of the measuring tank (312) to blow air into the inner cavity of the measuring tank (312).
9. The foaming equipment based on pulp fiber foam density control as described in claim 3, characterized in that, The discharge end of the conveying pump (2) is closely connected to the density measuring device (3).
10. The foaming equipment based on pulp fiber foam density control as described in claim 1, characterized in that, The delivery pump (2) includes, but is not limited to, positive displacement pumps, such as gear pumps, screw pumps or diaphragm pumps.