High-temperature-resistant adhesive packaging process and packaging equipment for humidifier

Abstract

The invention discloses a high-temperature-resistant adhesive packaging process and packaging equipment for a humidifier, and belongs to the technical field of fuel cells. The gradient glue injection and low-frequency vibration synergistic process without pre-blocking is provided for solving the problems that an existing hollow fiber membrane humidifier packaging process depends on manual pre-blocking, membrane holes are prone to being blocked, sealing performance and membrane climbing control are difficult to consider by a single glue type, the centrifugal exhaust efficiency is low, and membrane filaments are prone to being damaged by vibration equipment. The process comprises the following steps: firstly, injecting low-viscosity glue with the thickness of 2-4mm to form a sealing barrier with the climbing film length of 50-60mm, then injecting main sealant with the thickness of 40-50mm on the sealing barrier, and applying vertical low-frequency vibration with the frequency of 4-10Hz and the frequency of 3 minutes within 30 seconds after each time of glue injection so as to exhaust gas; a spring-rubber composite damping structure and a high-precision bearing table are adopted in corollary equipment, and it is ensured that the vibration direction is controllable, and a rubber layer is uniform. According to the invention, zero blockage and zero air hole are realized, the capacity of a single shift is more than 200 pieces, and the method is suitable for efficient and reliable packaging of the hollow fiber membrane humidifier of a fuel cell system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fuel cell technology, in particular to a high-temperature-resistant glue packaging device for a hollow fiber membrane humidifier in a fuel cell system and a packaging process thereof, and more particularly to the application of gradient glue injection, protective vibration exhaust and other technologies in the sealing of the end of the humidifier membrane assembly. BACKGROUND

[0002] Fuel cells are high-efficiency clean energy conversion devices, and their performance is highly dependent on the humidity control of the reaction gas. As the core component of the fuel cell system, the hollow fiber membrane humidifier uses the selective permeation characteristics of thousands of hollow fiber membranes to establish a water vapor pressure difference between the wet side and the dry side, achieving efficient humidification without liquid water contact, thereby maintaining the conductivity of the proton exchange membrane and the stability of the stack operation.

[0003] To ensure the normal functioning of the humidification function, the ends of the bundled hollow fiber membranes must be reliably sealed: on the one hand, to fix the fragile membrane filaments and prevent them from shifting or breaking during assembly or operation; on the other hand, to form an airtight end to prevent the reaction gas from bypassing through the pores between the hollow fiber membranes, thereby ensuring the isolation of the wet / dry side flow channels.

[0004] Therefore, the quality of the potting structure directly determines the sealing performance, effective membrane area utilization rate and long-term service life of the humidifier, and has important engineering significance.

[0005] Currently, the closest prior art in the industry uses a "manual pre-plugging + centrifugal potting" process: first, the hollow fiber membranes are loaded into the membrane box according to the specified number, the end face is cut to be neat, and then the end face is manually blocked by scraping or brushing with putty powder or high-viscosity silicone glue; before the blocking material is completely cured, the membrane filaments need to be manually dispersed to prevent sticking; finally, the assembly is loaded into a packaging mold, high-temperature-resistant potting glue (such as polyurethane or epoxy glue) is injected, and the assembly is placed in a centrifuge for centrifugal packaging. Although this method can achieve basic sealing, it has several defects in actual application.

[0006] First, the process is complicated and has poor reliability, which can easily cause membrane hole plugging. Since the internal channels of the hollow fiber membrane are connected, if the pre-plugging is not complete, the potting glue will seep into the membrane cavity, causing permanent plugging and rendering the membrane filament ineffective. Manual scraping cannot guarantee that each membrane filament is effectively covered, especially when the membrane bundle and the membrane box do not match in porosity or the end face is not cut evenly, the risk of incomplete plugging increases significantly. This not only reduces the effective number of hollow fiber membranes used, but also directly weakens the overall humidification efficiency of the humidifier.

[0007] The technical route of the field in solving the problem of membrane hole blockage is to follow the early manual pre-blocking method of microfiltration membrane module, and to realize the old idea of "physical plugging" through putty powder or silica gel. The existing technology focuses on "uniformity of pre-blocking material application" and "manual dispersion operation skill", and does not break through the process framework of "blocking first and then filling". Correspondingly, the present patent application creates a technical route of forming a sealed barrier by gradient glue injection without pre-blocking.

[0008] Second, the viscosity selection of the filling adhesive faces a fundamental contradiction. The mixed viscosity of polyurethane high-temperature glue is usually 200-1000 cps (centipoise), and the mixed viscosity of epoxy high-temperature glue is 1500-2500 cps.

[0009] When the viscosity is too large, the glue solution is difficult to fully infiltrate the gap between the densely arranged membrane filaments, leading to local sealing failure and causing gas bypass (the fluid that should flow through the lumen of the hollow fiber membrane bypasses through the pores between the hollow fiber membranes); When the viscosity is too small, the glue solution will climb up along the outer wall of the hollow fiber membrane due to capillary phenomenon, not only shortening the effective mass transfer length, but also making the membrane material brittle due to swelling or stress concentration, which is easy to break in subsequent processing.

[0010] The existing technology tries to balance this contradiction through single glue formula optimization, but it is difficult to meet the sealing integrity and membrane filament protection at the same time. In the field of filling adhesive selection, the thinking mode of "single glue completing all functions" has been continued for a long time, and the viscosity is regarded as a single parameter that needs to be compromised. The existing technology focuses on the "linear relationship between glue viscosity and sealing effect", ignoring the functional differences in different stages of membrane end sealing. Correspondingly, the present patent application creates a gradient packaging strategy of differential glue injection in different stages, and resolves the viscosity contradiction through the coordinated control of thickness and membrane climbing length.

[0011] Third, the centrifugal packaging efficiency is low, which seriously restricts the large-scale production. The current mainstream method relies on the high G force provided by the centrifuge to exclude air bubbles and promote glue filling, but the single-end centrifugation time is as long as 4-6 hours, and the maximum processing capacity is 4-6 products at a time, and two shifts can only produce about 12 products. This inefficient mode is difficult to meet the large-scale, low-cost supply demand of humidifiers in emerging markets such as fuel cell vehicles.

[0012] When improving the packaging efficiency, the technical route of the field is to realize the old method of "centrifugal intensification" by increasing the capacity of the centrifuge or prolonging the centrifugation time. The existing technology focuses on "centrifugal parameter optimization", and does not explore alternative solutions suitable for gentle degassing of high-density brittle membrane bundles across fields. Correspondingly, the present patent application creates a non-centrifugal high-efficiency new path of low-frequency vibration degassing and multi-piece parallel static curing.

[0013] Fourth, if vibration degassing is introduced, the existing equipment has poor adaptability and is easy to damage the membrane filaments or cause uneven glue layers.

[0014] The conventional vibration table is usually connected rigidly and excited at high frequency (20-50 Hz) to maximize energy transmission. However, hollow fiber membranes have high aspect ratio, low strength, and dense arrangement, and such vibration can easily cause membrane fatigue fracture or overall displacement. At the same time, the surface processing precision of the ordinary vibration platform is insufficient, which cannot guarantee the flatness of the bottom surface of the packaging mold, leading to uneven distribution of glue liquid and affecting the integrity of the sealing interface.

[0015] In the field of vibration equipment design, the technical route is to follow the "rigid and efficient" mode of industrial vibration table, without considering the special protection needs of precision brittle workpieces. The existing technology focuses on "vibration power improvement", without establishing a collaborative vibration reduction mechanism of "elastic buffer + direction constraint + surface precision control". Correspondingly, the present application creates a protective vibration system integrating spring-rubber pad composite support and high-precision platform (≤0.02 mm).

[0016] It is worth noting that the "low-frequency vibration" referred to in the present application means a vibration frequency of 4-10 Hz, which is significantly lower than the 20-50 Hz high-frequency vibration commonly used in existing industrial vibration tables. Due to the high aspect ratio and low stiffness of hollow fiber membranes, their first-order bending natural frequency is usually above 15 Hz. Using 4-10 Hz excitation can avoid the resonance region and effectively prevent membrane fatigue fracture, while ensuring that the bubbles escape sufficiently before the glue liquid initial setting.

[0017] In summary, the existing humidifier packaging technology is bound by historical path dependence, relying excessively on manual pre-blocking and centrifugal forced means, and cannot balance sealing reliability, membrane integrity, process simplicity, and production efficiency. The above shortcomings have seriously hindered the industrialization process of high-performance humidifiers. Therefore, there is an urgent need for a new type of humidifier high-temperature-resistant glue packaging equipment and packaging process that can save the pre-blocking process, accurately control the glue liquid climbing membrane, effectively remove bubbles, support mass parallel production, and ensure membrane safety and glue layer uniformity through a special vibration platform, ultimately achieving the technical goal of zero blockage, zero air hole, controllable climbing membrane, and single-shift production capacity exceeding 200 pieces. The necessity of the above improvement is the core problem to be solved by the present patent. SUMMARY

[0018] The present application aims to provide a humidifier gradient filling process that can reliably seal the end of a hollow fiber membrane without pre-blocking, to overcome the fundamental defects of membrane hole blockage, sealing failure, and low production efficiency caused by reliance on pre-blocking operations in the prior art.

[0019] To achieve the above-mentioned purpose, the humidifier high-temperature-resistant glue packaging process of the present application is used to seal the end of a humidifier containing thousands of hollow fiber membranes, and the packaging process comprises the following steps: The bundle of hollow fiber membranes is loaded into the packaging mold without any pre-blocking operation; A first layer of high-temperature resistant glue is injected into the end of the membrane bundle to form a thin glue layer with a thickness of 2-4 mm, so that the glue liquid climbs up to a length of 50-60 mm along the outer wall of the hollow fiber membrane, and is left to stand for 3-6 hours to preliminarily solidify and form a sealing barrier to prevent the subsequent glue liquid from penetrating into the membrane holes; A second layer of high-temperature resistant glue is injected above the sealing barrier to form a main sealing layer with a thickness of 40-50 mm, and the climbing length of the second layer of glue liquid does not exceed 60 mm; After each glue injection is completed and before the glue liquid is initially solidified, low-frequency vibration with a frequency of 4-10 Hz and a duration of 3 minutes is applied to the packaging mold to expel the air bubbles in the glue; After the glue is completely solidified, the mold is removed, and the solidified glue with a length of 10-20 mm is cut off from both ends to expose the clean end face of the hollow fiber membrane that is not contaminated by the glue.

[0020] The climbing length of the second layer of glue liquid does not exceed the climbing length of the first layer of glue liquid.

[0021] The low-frequency vibration is started within 30 seconds after each glue injection is completed.

[0022] The first layer of glue and the second layer of glue are the same or different kinds of high-temperature resistant glue, and polyurethane glue and epoxy glue can be combined to improve the adaptability of the process to glue with a wide viscosity range. When the first layer of glue and the second layer of glue are different kinds of high-temperature resistant glue, the first layer of glue is low-viscosity glue, and the second layer of glue is high-viscosity glue.

[0023] The cutting operation is completed by mechanical milling or wire cutting.

[0024] The application also discloses a packaging device for implementing the packaging process, which comprises a vibration platform, a packaging mold and a glue liquid injection system. The vibration platform comprises a base, a bearing table and a composite damping structure connecting the base and the bearing table. The composite damping structure comprises an upper fixed ring, a lower fixed ring, rubber pads nested in the upper fixed ring and the lower fixed ring and springs, the upper ends of the springs are pressure-connected with the rubber pads in the upper fixed ring, and the lower ends of the springs are pressure-connected with the rubber pads in the lower fixed ring; the surface processing precision of the bearing table is ≤0.02 mm; the upper fixed ring is connected to the bearing table upward, and the lower fixed ring is connected to the base downward; a vibration generator is connected to the bottom surface of the bearing table; the bearing table bears the packaging mold. Four sets of composite damping structures are connected between the base and the bearing table, and the four sets of composite damping structures are respectively located at the four corners of the base and the bearing table.

[0025] The upper surface of the support platform has a groove for limiting the displacement of the packaging mold during vibration, and the packaging mold is placed in the groove. The packaging mold includes a base plate, and the upper surface of the base plate is provided with an upward-opening packaging groove. The packaging groove matches the humidifier housing. The humidifier housing is placed downward on the groove wall of the packaging groove, and the humidifier housing is connected to a glue injection tube. The outer end of the glue injection tube is connected to a glue injection machine, and the inner end of the glue injection tube communicates with the packaging groove.

[0026] The present invention has the following advantages: The encapsulation process of this invention eliminates the need for manual pre-plugging, fundamentally avoiding membrane pore blockage caused by leakage; the controllable creep of the first layer of adhesive forms a self-sealing barrier, effectively blocking the penetration of the second layer of adhesive; two low-frequency vibrations ensure that air bubbles are fully discharged; more than 200 products can be processed in parallel in a single shift, significantly improving efficiency.

[0027] Starting low-frequency vibration within 30 seconds after glue application ensures the glue remains at a low viscosity, maximizing venting efficiency.

[0028] Using different combinations of adhesives can actively cover a wide viscosity range: First layer of adhesive: Low viscosity adhesive (such as polyurethane potting compound, 200–1000 cps) is preferred because of its good flowability and ability to climb up the outer wall of the membrane for 50–60 mm to form a continuous sealing barrier. Second layer of adhesive: High viscosity adhesive (such as epoxy potting compound, 1500–2500 cps) can be selected because of its strong cohesion and low shrinkage, which is suitable for building a dense main sealing layer with a thickness of up to 40–50 mm. Results: By matching different functional requirements in stages, the entire process can effectively utilize colloids in the full range of 200–2500 cps, achieving "low viscosity for penetration and high viscosity for strength".

[0029] At this point, using different types of adhesives is a proactive design approach to expand viscosity adaptability.

[0030] The use of the same type of adhesive demonstrates the robustness of the encapsulation process of this invention: If only one type of adhesive is available (e.g., only medium viscosity epoxy adhesive, ~2000cps), this process can still be used to make the first layer of adhesive form an effective barrier under limited climbing (e.g., climbing 40–50 mm) by controlling the amount of adhesive injected, the settling time, and the vibration parameters, and then the second layer of adhesive can be stacked on top of it. Although its performance is slightly inferior to the optimized combination, it can still avoid clogging and complete the seal, indicating that the process also has good tolerance for single adhesive types.

[0031] Therefore, the feasibility of the encapsulation process of the present invention with the same type of adhesive demonstrates the robustness and universality of the process.

[0032] The encapsulation device in this invention can achieve controllable vertical vibration to prevent lateral shearing of the film fibers; the high-precision surface ensures a flat bottom surface of the adhesive layer.

[0033] The groove can limit the displacement of the encapsulation mold during vibration, ensuring uniform distribution of the adhesive. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of the humidifier housing and the packaging mold.

[0035] Figure 2 yes Figure 1 AA sectional view.

[0036] Figure 3 yes Figure 1 A three-dimensional image.

[0037] Figure 4 This is a schematic diagram of the structure where the humidifier housing and the packaging mold are assembled together and placed on a vibration platform.

[0038] Figure 1 As can be seen, the lower part of the glue injection tube 10 bends to the right in the figure, therefore Figure 2 The bottom of the glue injection tube 10 could not be reached during the cutting process; Figure 2 The red dashed line in the middle shows the direction of the bottom of the dispensing tube 10, indicating that the final dispensing position of the dispensing tube 10 is to dispense the dispensing material into the encapsulation groove 2. Detailed Implementation

[0039] like Figures 1 to 4 As shown, the high-temperature resistant adhesive encapsulation process of the humidifier is used to seal the end of the humidifier 3, which contains thousands of hollow fiber membranes. The humidifier 3 includes a shell and an internal hollow fiber membrane bundle, wherein the shell is used in this invention to cooperate with the encapsulation groove 2.

[0040] The packaging process includes the following steps: The hollow fiber membrane bundles are loaded into the encapsulation mold without any pre-plugging operation; Inject the first layer of high-temperature resistant adhesive into the end of the hollow fiber membrane bundle to form a thin adhesive layer with a thickness of 2–4 mm (millimeters, including both ends, the same below). Let the adhesive climb up the outer wall of the hollow fiber membrane to 50–60 mm, and let it stand for 3–6 hours to allow it to initially cure, forming a sealing barrier that prevents subsequent adhesive from penetrating into the membrane pores. A second layer of high-temperature resistant adhesive is injected above the sealing barrier to form a main sealing layer with a thickness of 40–50 mm, and the climbing length of the second layer of adhesive does not exceed 60 mm; in this invention, "climbing" specifically refers to the phenomenon of the adhesive climbing upward along the outer wall of the hollow fiber membrane due to capillary action, and the climbing length L refers to the maximum climbing value measured from the end face of the adhesive layer.

[0041] After each injection of adhesive and before the adhesive initially sets, apply low-frequency vibration of 4–10 Hz for 3 minutes to the encapsulation mold to remove air bubbles inside the adhesive. The "low frequency" mentioned in this invention refers to the 20-50Hz high-frequency excitation commonly used in conventional industrial vibration equipment (such as vibration tables, vibration degassing machines, etc.). This invention limits the vibration frequency to 4-10Hz. This range has been experimentally verified to effectively remove air bubbles while avoiding resonance damage or lateral displacement of high aspect ratio hollow fiber membranes.

[0042] The 4–10Hz frequency range is significantly lower than the 20–50Hz high-frequency vibration commonly used in existing industrial vibration tables. Due to the high aspect ratio and low stiffness of hollow fiber membranes, their first-order bending natural frequency is usually above 15Hz. Using 4–10Hz excitation can avoid the resonance zone, effectively prevent membrane fiber fatigue breakage, and ensure that bubbles can escape fully before the adhesive initially solidifies.

[0043] After the colloid has fully cured, demold it (fully cured means that the hardness of the colloid reaches Shore D70 or above after standing at 25°C for 24 hours), and cut off 10-20 mm of cured colloid from each end (i.e. cut off 10-20 mm deep end colloid layer) to expose the clean end face of the hollow fiber membrane that has not been contaminated by the colloid.

[0044] The high-temperature resistant adhesive is either polyurethane or epoxy, wherein the mixed viscosity of the polyurethane adhesive at 25°C is 200–1000 cps, and that of the epoxy adhesive is 1500–2500 cps; the curing process is carried out naturally at 25°C without heating.

[0045] The encapsulation process of this invention eliminates the need for manual pre-plugging, fundamentally avoiding membrane pore blockage caused by leakage; the controllable creep of the first layer of adhesive forms a self-sealing barrier, effectively blocking the penetration of the second layer of adhesive; two low-frequency vibrations ensure that air bubbles are fully discharged; more than 200 products can be processed in parallel in a single shift, significantly improving efficiency.

[0046] "No pre-blocking operation" is one of the essential features that distinguishes it from existing technologies; the membrane climbing length of 50–60 mm is determined based on membrane embrittlement criticality experiments.

[0047] The technical approach in this invention is crucial. Before the new technical route of this invention was designed (see the introduction in the background section), the technical solution of this invention did not follow the natural extension path of the scientific and technological tree in this field. After the new technical route of this invention was designed and the general technical solution was designed, specific process parameters such as the thickness of the thin adhesive layer, etc., can be designed according to their function or determined through experiments. For example, the specific thickness of the thin adhesive layer and the main sealing layer can be determined by experiments on the minimum filling amount and rheological properties of the sealing barrier.

[0048] The membrane climbing length parameter is designed to balance sealing performance with the effective length of the membrane fibers; the vibration time parameter is designed to ensure venting is completed before the adhesive viscosity increases significantly. Specifically, high-temperature resistant adhesives (such as epoxy or polyurethane) begin cross-linking after mixing, and the viscosity increases non-linearly over time: Initial stage (0–10 min): low viscosity, good flowability, and bubbles easily rise and escape; Middle stage (10–30 min): viscosity increases rapidly, and bubble migration resistance increases dramatically; Late stage (>30 min): the colloid enters a gel state, and bubbles are "frozen" inside. If vibration is too late or insufficient, micron-sized bubbles cannot escape completely, leading to the formation of micropores after curing and causing gas bypass. Tests show that low-frequency vibration, started within 30 seconds of adhesive injection and lasting for 3 minutes, precisely covers the lowest viscosity window of the adhesive, enabling efficient venting without disturbing the initial solidification structure.

[0049] The test showed that omitting any step of the packaging process in this invention resulted in blockage or pore defects, further demonstrating that the steps are synergistic and inseparable.

[0050] The climbing length of the second adhesive layer does not exceed that of the first adhesive layer. This is achieved by controlling the viscosity of the second adhesive layer to be no lower than that of the first layer or by reducing the amount of adhesive applied. The fact that the climbing length of the second adhesive layer does not exceed that of the first layer prevents repeated climbing and extends the fibrous embrittlement zone, ensuring effective mass transfer length.

[0051] The low-frequency vibration is initiated within 30 seconds after each dispensing. A vibration delay exceeding one minute will result in air bubble retention.

[0052] Starting low-frequency vibration within 30 seconds after glue application ensures the glue remains at a low viscosity, maximizing venting efficiency.

[0053] The first and second adhesive layers are the same or different types of high-temperature resistant adhesives. Polyurethane adhesives and epoxy adhesives can be used in combination to improve the process's adaptability to colloids with a wide viscosity range (200–2500 cps). When the first and second layers of adhesive are different types of high-temperature resistant adhesives, the first layer should be a low-viscosity adhesive, and the second layer should be a high-viscosity adhesive.

[0054] Different combinations of adhesives can actively cover a wide viscosity range: First layer of adhesive: Low viscosity adhesive (such as polyurethane potting compound, 200–1000 cps) is preferred because of its good flowability and ability to climb up the outer wall of the membrane for 50–60 mm to form a continuous sealing barrier. Second layer of adhesive: High viscosity adhesive (such as epoxy potting compound, 1500–2500 cps) can be selected because of its strong cohesion and low shrinkage, which is suitable for building a dense main sealing layer with a thickness of up to 40–50 mm. Results: By matching different functional requirements in stages, the entire process can effectively utilize colloids in the full range of 200–2500 cps, achieving "low viscosity for penetration and high viscosity for strength".

[0055] At this point, using different types of adhesives is a proactive design approach to expand viscosity adaptability.

[0056] The use of the same type of adhesive demonstrates the robustness of the encapsulation process of this invention: If only one type of adhesive is available (e.g., only medium viscosity epoxy adhesive, ~2000cps), this process can still be used to make the first layer of adhesive form an effective barrier under limited climbing (e.g., climbing 40–50 mm) by controlling the amount of adhesive injected, the settling time, and the vibration parameters, and then the second layer of adhesive can be stacked on top of it. Although its performance is slightly inferior to the optimized combination, it can still avoid clogging and complete the seal, indicating that the process also has good tolerance for single adhesive types.

[0057] Therefore, the feasibility of the encapsulation process of the present invention with the same type of adhesive demonstrates the robustness and universality of the process.

[0058] The resection operation is performed using mechanical milling or wire cutting. The flatness error of the resection rear surface is ≤0.1mm. Using mechanical milling or wire cutting to complete the resection effectively exposes unobstructed membrane pores, eliminating the need for secondary cleaning.

[0059] The present invention also discloses a packaging apparatus for carrying out the packaging process, including a vibration platform, a packaging mold and a glue injection system; The vibration platform includes a base 4, a support platform 5, and a composite damping structure connecting the base 4 and the support platform 5. The composite damping structure includes an upper fixing ring 6, a lower fixing ring 7, rubber pads nested within the upper fixing ring 6 and the lower fixing ring 7, and a spring 8. The upper end of the spring 8 is pressed against the rubber pad inside the upper fixing ring 6, and the lower end of the spring 8 is pressed against the rubber pad inside the lower fixing ring 7. The surface machining accuracy of the support platform 5 is ≤0.02mm. The upper fixing ring 6 is connected upward to the support platform 5, and the lower fixing ring 7 is connected downward to the base 4. A vibration generator 9 is connected to the bottom surface of the support platform 5. The support platform 5 supports the encapsulation mold. Four sets of composite damping structures are connected between the base 4 and the support platform 5, and the four sets of composite damping structures are located at the four corners of the base 4 and the support platform 5 respectively.

[0060] In this invention, a fixed ring constrains the lateral degree of freedom of spring 8; a rubber pad provides high-frequency damping; and spring 8 tunes the system's natural frequency to around 4–10 Hz. The rubber pad is a conventional technology and is not shown in the figure.

[0061] The encapsulation device in this invention can achieve controllable vertical vibration to prevent lateral shearing of the film fibers; the high-precision surface ensures a flat bottom surface of the adhesive layer.

[0062] The upper surface of the support platform 5 has a groove for limiting the displacement of the packaging mold during vibration. The packaging mold is placed in the groove. The packaging mold includes a base plate 1 with a packaging groove 2 facing upwards. The packaging groove 2 matches the housing of the humidifier 3. The housing of the humidifier 3 covers the wall of the packaging groove 2 downwards, and the housing of the humidifier 3 is connected to a dispensing tube 10. The outer end of the dispensing tube 10 is connected to a dispensing machine, and the inner end of the dispensing tube 10 communicates with the packaging groove 2. The groove and the dispensing machine are conventional technologies and are not shown in detail in the figure. The groove can limit the displacement of the packaging mold during vibration and ensure uniform distribution of adhesive. Example

[0063] The packaging process using the aforementioned packaging equipment comprises the following specific steps: S1. Mold pretreatment and mold positioning.

[0064] A release agent is evenly sprayed or applied to the inner surface of the packaging mold to form a thin oil film on the bottom and side walls of the mold. The hollow fiber membrane is cut neatly to size (after being placed into the packaging mold, the membrane end face is less than 1mm from the bottom surface of the mold) and placed into the membrane box of the humidifier 3. The membrane box is then placed into the housing of the humidifier 3. One end of the housing of the humidifier 3 is placed downwards into the packaging groove 2 of the packaging mold, so that the housing and the wall of the packaging groove 2 fit tightly to form a complete humidifier 3 assembly. Then, the entire packaging mold is placed in the groove on the upper surface of the bearing platform 5 of the vibration platform, and the groove limits the circumferential movement of the packaging mold.

[0065] S2. First injection of adhesive.

[0066] The first layer of high-temperature resistant adhesive (polyurethane adhesive, viscosity 300cps at 25℃, curing time > 3h) is injected into the encapsulation tank 2 through the adhesive injection tube 10 from the moisture port 11 of the humidifier 3, forming a thin adhesive layer with a thickness of 2mm; the adhesive rises up to 50mm along the outer wall of the hollow fiber membrane by capillary action.

[0067] S3. First vibration to exhaust air.

[0068] Within 30 seconds after the first injection of adhesive, the vibration generator 9 connected to the bottom of the support platform 5 is activated to apply low-frequency vertical vibration at a frequency of 4Hz for a duration of 3 minutes to the encapsulation mold. The vibration energy is transmitted through four sets of composite damping structures. Among them, the spring 8 tunes the system's natural frequency to around 4–10Hz, the rubber pad provides high-frequency damping, and the upper fixing ring 6 and the lower fixing ring 7 constrain the lateral displacement of the spring 8 to ensure that the vibration direction is vertical, effectively expelling air bubbles inside the adhesive without damaging the film fibers.

[0069] S4. Initial curing.

[0070] After vibration, the membrane is left to stand at 25°C for 3 hours to allow the first layer of adhesive to initially cure, forming a sealing barrier that prevents subsequent adhesive from penetrating into the membrane pores.

[0071] S5. Second injection of adhesive.

[0072] A second layer of high-temperature resistant adhesive (epoxy adhesive, viscosity 2000cps at 25℃) is injected again through the adhesive injection system to form a main sealing layer with a thickness of 40mm, and the climbing length of the second layer of adhesive is controlled to not exceed 60mm.

[0073] S6. Second vibration exhaust.

[0074] Within 30 seconds after the second layer of adhesive is applied, the vibration generator 9 is restarted and vibrated at a low frequency with the same parameters (4Hz, 3min) to expel air bubbles from the second layer of adhesive.

[0075] S7. Complete curing and demolding.

[0076] After natural and complete curing at 25°C, the encapsulation mold is removed from the groove of the support platform 5 and separated from the housing of the humidifier 3 to complete the demolding.

[0077] S8. End face finishing.

[0078] Using mechanical milling, 10mm of cured adhesive is removed from each end of the humidifier's three components (i.e., 10–20mm deep end adhesive layer is removed), exposing the clean end face of the hollow fiber membrane that is not contaminated by the adhesive. The flatness error of the end face is ≤0.1mm. Example

[0079] Except for the following parameters, the remaining steps are the same as in Example 1: S2: The first layer of adhesive is 3mm thick, and the film climbing length is 50mm; S3 and S6: Vibration frequency is 8Hz; S5: The thickness of the second layer of adhesive is 45mm; S8: The cut thickness is 15mm. Example

[0080] Except for the following parameters, the remaining steps are the same as in Example 1: S2: The first layer of adhesive is 4mm thick, and the film climbing length is 50mm; S3 and S6: Vibration frequency is 10Hz; S5: The thickness of the second layer of adhesive is 50mm; S8: The cut thickness is 20mm.

[0081] Note: The above three embodiments cover typical values ​​of each parameter range in claim 1 (thin adhesive layer 2–4 mm, main adhesive layer 40–50 mm, frequency 4–10 Hz, cut-off 10–20 mm), verifying the feasibility and stability of the present invention under a wide parameter window.

[0082] Verification section To verify the necessity of the "two-stage vibration exhaust" step in this invention, the following comparative examples were set up: Comparative Example 1 The same process parameters as in Example 3 were used, but step S3 (i.e., vibration was not performed after the first injection) was omitted, while the remaining steps remained unchanged. Specifically, it included: first injection (4mm, 50mm film climbing) → standing for 3 hours → second injection (50mm) → second vibration (10Hz, 3min) → curing → cutting off 20mm.

[0083] Comparative Example 2 The same process parameters as in Example 3 were used, but step S6 (i.e., vibration was not performed after the second glue application) was omitted; the remaining steps remained unchanged. Specifically, these included: First injection of adhesive (4mm, 50mm for film climbing) → First vibration (10Hz, 3min) → Let stand for 3 hours → Second injection of adhesive (50mm, ≤60mm for film climbing) → No vibration → Complete curing at 25℃ → Demolding and cutting off 20mm.

[0084] Comparative Example 3 The same process parameters as in Example 3 were used, but steps S3 and S6 were omitted (i.e., no vibration after both injections), while the remaining steps remained unchanged.

[0085] All comparative examples used the same complete process as Example 3, including: spraying release agent onto the packaging mold, not performing any pre-blocking operation when loading the membrane bundle, using the same type of adhesive and injection path, etc., with the only difference being the vibration step.

[0086] Table 1: Performance Comparison of Examples and Comparative Examples

[0087] illustrate: "Membrane pore blockage rate" refers to the percentage of hollow fiber membranes blocked due to adhesive seepage into the inner cavity; a blockage rate of 1.0% means 10 membranes are blocked per thousand membranes; 1.5% means 15 membranes are blocked. "Porosity defects in the adhesive layer" refer to the micron-sized air bubbles visible inside the cured colloid, which can be confirmed by X-ray or cross-section microscopy. All test samples were prepared and tested under the same conditions (25℃, RH≤50%).

[0088] Results analysis: Examples 1–3 all achieved zero clogging and zero porosity, proving that the process of the present invention is stable and reliable; In Comparative Example 1, although there were few air bubbles in the first layer of adhesive due to the lack of the first vibration, the adhesive liquid carried air into the membrane gap during the membrane climbing process, resulting in local blockage (1%). In Comparative Example 2, due to the lack of a second vibration, air bubbles in the high-viscosity main adhesive layer could not be discharged, forming a gas bypass channel (1 pore). Comparative Example 3 showed that the simultaneous absence of two vibrations resulted in the superposition of blockage and pore defects, leading to product failure.

[0089] Conclusion: The two low-frequency vibrations target the rheological properties of different adhesive layers and efficiently degas within their respective viscosity windows. Both are indispensable (both vibrations are essential technical features) and together constitute the key technical features for achieving the "zero clogging, zero porosity" effect.

[0090] The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A high-temperature resistant adhesive encapsulation process for humidifiers, used to seal the ends of humidifiers containing thousands of hollow fiber membranes, characterized in that: The packaging process includes the following steps: The hollow fiber membrane bundles are loaded into the encapsulation mold without any pre-plugging operation; Inject the first layer of high-temperature resistant adhesive into the end of the membrane bundle to form a thin adhesive layer with a thickness of 2–4 mm. Let the adhesive climb up the outer wall of the hollow fiber membrane to a length of 50–60 mm. Let it stand for 3–6 hours to allow it to initially cure, forming a sealing barrier that prevents subsequent adhesive from penetrating into the membrane pores. A second layer of high-temperature resistant adhesive is injected above the sealing barrier to form a main sealing layer with a thickness of 40–50 mm, and the climbing length of the second layer of adhesive does not exceed 60 mm. After each injection of adhesive and before the adhesive initially sets, apply low-frequency vibration of 4–10 Hz for 3 minutes to the encapsulation mold to remove air bubbles inside the adhesive. After the colloid has fully cured, demold it and cut off 10–20 mm of cured colloid from each end to expose the clean end face of the hollow fiber membrane that has not been contaminated by the colloid.

2. The high-temperature resistant adhesive encapsulation process for humidifiers according to claim 1, characterized in that: The climbing length of the second layer of adhesive does not exceed the climbing length of the first layer of adhesive.

3. The high-temperature resistant adhesive encapsulation process for humidifiers according to claim 1, characterized in that: The low-frequency vibration is initiated within 30 seconds after each glue injection is completed.

4. The high-temperature resistant adhesive encapsulation process for humidifiers according to claim 1, characterized in that: The first and second adhesive layers can be the same or different types of high-temperature resistant adhesives. Polyurethane adhesives and epoxy adhesives can be used in combination to improve the process's adaptability to adhesives with a wide viscosity range. When the first layer of adhesive and the second layer of adhesive are different types of high-temperature resistant adhesives, the first layer of adhesive should be a low-viscosity adhesive. The second layer of adhesive uses a high-viscosity adhesive.

5. The high-temperature resistant adhesive encapsulation process for humidifiers according to claim 1, characterized in that: The cutting operation is performed by mechanical milling or wire cutting.

6. A packaging apparatus for carrying out the packaging process as described in any one of claims 1–3, characterized in that: Includes a vibration platform, packaging mold, and adhesive injection system; The vibration platform includes a base, a support platform, and a composite damping structure connecting the base and the support platform; The composite damping structure includes an upper fixed ring, a lower fixed ring, rubber pads nested within the upper and lower fixed rings, and a spring. The upper end of the spring is pressed against the rubber pad in the upper fixed ring, and the lower end of the spring is pressed against the rubber pad in the lower fixed ring. The surface machining accuracy of the support platform is ≤0.02mm. The upper fixed ring is connected upward to the support platform, and the lower fixed ring is connected downward to the base. A vibration generator is connected to the bottom surface of the support platform. The support platform supports the encapsulation mold. Four sets of composite damping structures are connected between the base and the support platform, and the four sets of composite damping structures are located at the four corners of the base and the support platform, respectively.

7. The packaging equipment according to claim 6, characterized in that: The upper surface of the support platform has a groove for limiting the displacement of the packaging mold during vibration, and the packaging mold is placed in the groove. The packaging mold includes a base plate, and the upper surface of the base plate is provided with an upward-opening packaging groove. The packaging groove matches the humidifier housing. The humidifier housing is placed downward on the groove wall of the packaging groove, and the humidifier housing is connected to a glue injection tube. The outer end of the glue injection tube is connected to a glue injection machine, and the inner end of the glue injection tube communicates with the packaging groove.

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