Preparation method of total heat exchanger core and total heat exchanger core

Abstract

The invention relates to the technical field of total heat exchangers, and discloses a total heat exchanger core body preparation method and a total heat exchanger core body, the method is an integral injection molding method of a total heat exchanger, the total heat exchanger core body is prepared through a front mold and a rear mold, an exchange membrane is subjected to heat exchange treatment through the rear mold, and the total heat exchanger core body is obtained. The temperature of the exchange membrane can be kept below the softening point all the time, it is guaranteed that a coating on the exchange membrane is not damaged, in addition, the air duct ribs which are thinner and more stable in shape can be obtained by controlling the exchange temperature, and the heat exchange efficiency of the unit area of the total heat exchanger core can be remarkably improved; in addition, the total heat exchanger core manufactured through integral injection molding is free of degumming risk and high in sealing performance.

Description

Technical Field

[0001] The present invention relates to the technical field of total heat exchangers, and in particular to a preparation method of a total heat exchanger core body and a total heat exchanger core body. Background Art

[0002] A total heat exchanger is an air purification device that can discharge indoor air through filtration and input outdoor air into the room after filtration, realizing the replacement of indoor and outdoor air. During the heat exchange process, the total heat exchanger can perform heat exchange on the air to be discharged and the air to be input in the casing, thereby achieving heat preservation for the room and reducing energy consumption.

[0003] The heat exchange component of the total heat exchanger is the core body. Currently, the total heat exchanger core body in the prior art is mainly composed of a heat exchange membrane and a gas flow channel. The heat exchange membrane can isolate the air flow but allow water molecules to pass through. When the output air and the input air flow in the gas flow channel, heat and water molecules can be exchanged through the heat exchange membrane; currently, the structures of heat exchange cores are diverse. For example, a square convection plate type total heat exchanger core body disclosed in CN203629387U is made by stacking an exchange membrane and a keel in sequence. In addition, a total heat exchanger core body and a total heat exchanger disclosed in the prior art CN113865380A point out that the exchange membrane of the total heat exchanger core body in the prior art is compounded with a heat exchange core plate or a keel using an adhesive, and problems such as glue peeling and air leakage, high processing costs, and more complex processes are likely to occur during the adhesive compounding.

[0004] Currently, although the problem of glue peeling and air leakage can be solved by adjusting the structures of the core plate and the exchange membrane, the problem of glue peeling of the exchange membrane still exists. Therefore, in view of the problem of glue peeling of the exchange membrane, those skilled in the art propose to use an integral injection molding method to integrally form the exchange membrane and the skeleton. However, the material of the exchange membrane is usually PP or PE, while the material of the skeleton is ABS, which results in low compatibility and low composite strength when the two are compounded; therefore, in view of the above problems, those skilled in the art propose to modify the PP material so that the strength of the modified PP is close to that of ABS. The shrinkage rate of the PP material is smaller than that of ABS. Using the PP material can ensure the flatness of the membrane and can ensure excellent heat exchange efficiency under a low-height (1.5 - 2 mm) air duct. In addition, the PP material has excellent compatibility with the exchange membrane, ensuring excellent composite strength of the PP material; when the present invention actually operates on the above content, it is found that there is also a problem that the rubber material changes the state of the heat exchange membrane during the integral injection molding process. Summary of the Invention

[0005] In view of the problem that the glue material changes the state of the exchange membrane during the integral injection molding of the total heat exchanger core in the prior art, the present invention provides a preparation method for a total heat exchanger core and a total heat exchanger core. The method uses a front mold and a rear mold to prepare the total heat exchanger core. The exchange membrane is placed in the mold cavity of the rear mold. The front mold is a skeleton injection mold. The rear mold performs heat exchange treatment on the exchange membrane. The front mold performs injection molding. Through the heat exchange treatment of the exchange membrane, the glue material of the front mold can quickly crystallize and solidify after contacting the exchange membrane to complete the composite of the skeleton and the exchange membrane, preventing the exchange membrane from softening and deforming due to excessive temperature when contacting the glue material. Moreover, the heat exchange treatment can obtain thinner air duct ribs, thereby increasing the heat exchange efficiency per unit area of the total heat exchanger.

[0006] The specific technical solution of the present invention is as follows: A preparation method for a total heat exchanger core includes the following steps: using a front mold and a rear mold to prepare the total heat exchanger core, placing the exchange membrane in the mold cavity of the rear mold, closing the rear mold and the front mold, melting the skeleton raw material to make the skeleton glue material, and then injecting the skeleton glue material into the front mold for injection molding. The rear mold performs heat exchange treatment on the exchange membrane, and the heat exchange treatment maintains the temperature of the exchange membrane at 16 - 20°C.

[0007] The present invention provides a preparation method for a total heat exchanger core. The method uses a front mold and a rear mold to prepare the heat exchanger core. The prepared total heat exchanger core is integrally injection molded without the problem of glue separation and air leakage. During the actual operation of the present invention, it is found that since the thickness of the exchange membrane is only 0.02 mm and there is a coating that is not resistant to high temperature on the surface, when the front mold glue material contacts the exchange membrane, the high-temperature glue material will heat the exchange membrane, causing the exchange membrane to soften and damage the coating of the exchange membrane. Therefore, the present invention performs heat exchange treatment on the rear mold for the above problems. The surface of the coating is placed on the rear mold side to avoid direct contact with the glue position. The heat exchange treatment can maintain the temperature of the exchange membrane always below the softening point and ensure that the coating on the exchange membrane is not damaged. In addition, the present invention also finds that when the rear mold performs heat exchange treatment on the exchange membrane, it can accelerate the solidification speed of the glue material of the front mold, enable the front mold to be quickly formed, obtain thinner air duct ribs, and increase the air duct spacing between the ribs, thereby significantly improving the heat exchange efficiency per unit fixed area of the total heat exchanger.

[0008] Preferably, the skeleton raw material includes, by mass: 45 - 49 parts of homopolypropylene, 23 - 27 parts of block copolymerized polypropylene, 6 - 10 parts of grafting agent, 0.5 - 1 part of antioxidant, 0.5 - 1 part of lubricant, 0.5 - 1 part of nucleating agent, 0.1 - 1 part of dispersant, and 20 - 21 parts of glass fiber.

[0009] The main functions of the skeleton raw materials used in the present invention are as follows: The combination of homopolypropylene and block copolymerized polypropylene can improve the fluidity of the rubber compound and the filling speed of the rubber compound in the front mold; glass fiber can improve the strength of the skeleton raw materials; the nucleating agent can increase the solidification speed of the rubber compound; the dispersant can evenly disperse particulate matter in the resin material and improve the homogeneity of the skeleton; the antioxidant can improve the antioxidant performance of the resin material and enhance the durability of the skeleton. Compared with the skeleton made of ABS material, the skeleton made of this skeleton raw material has less shrinkage, has less impact on the flatness of the exchange membrane, excellent structural strength, and a stable skeleton structure is formed.

[0010] Preferably, the heat exchange treatment uses liquid heat exchange, and the liquid is water.

[0011] Preferably, the gap between the front mold and the exchange membrane after film combination is 0.01 - 0.03 mm.

[0012] In the present invention, a gap is formed between the front mold and the exchange membrane after film combination. The formed gap can protect the membrane during injection molding, without damaging the tissue of the membrane, making the movement of the rubber compound towards the membrane smoother. An exhaust groove is provided in the outer circle, and there is clearance inside to facilitate the rapid injection molding of the rubber compound, shortening the injection molding time. In addition, the size of the gap affects the shape of the bottom of the air duct rib. When the gap is too large, the exchange membrane cannot quickly cool the rubber compound between the exchange membrane and the gap of the front mold. Due to the large fluidity of the rubber compound, the un-solidified rubber compound between the gaps overflows, resulting in a significant change in the shape of the air duct rib formed after final solidification, thus affecting the heat exchange efficiency of the exchange membrane.

[0013] Preferably, the injection time is that the injection shot time ≤ 3 s, and the total molding cycle time is ≤ 70 s.

[0014] A total heat exchanger core includes a skeleton and an exchange membrane compounded on the skeleton. The skeleton includes an outer frame and a plurality of air duct ribs provided on the outer frame. The total heat exchanger core is made by the above preparation method.

[0015] Preferably, a reinforcing rib is connected between the air duct rib and its adjacent air duct rib.

[0016] Preferably, the width of the air duct rib is 0.6 - 1 mm.

[0017] Preferably, the height of the air duct rib is 1.5 - 2 mm.

[0018] Preferably, the exchange membrane is one of a PP membrane and a PE membrane.

[0019] The present invention also provides a total heat exchanger core manufactured by the above preparation method. The exchange membrane and the skeleton of the core are integrally injection-molded, without adhesives and the risk of degumming, with high sealing performance. The air duct rib of the core is thin in thickness, and the heat exchange efficiency per unit area is high.

[0020] Compared with the prior art, the present application has the following technical effects: The present invention provides a method for integrally injection-molding a total heat exchanger core. The method prepares the total heat exchanger core through a front mold and a rear mold. The method performs heat exchange treatment on the exchange membrane through the rear mold, which can maintain the temperature of the exchange membrane always below the softening point and ensure that the coating on the exchange membrane is not damaged. In addition, by controlling the exchange temperature, air duct ribs with thinner thickness and more stable shape can be obtained, which can significantly improve the heat exchange efficiency per unit area of the total heat exchanger core. In addition, the total heat exchanger core integrally injection-molded has no risk of degumming and high sealing performance. Description of the Drawings

[0021] Figure 1 It is a schematic structural diagram of the total heat exchanger core of the present invention.

[0022] Figure 2 It is a schematic structural diagram of the front mold and the rear mold of the present invention.

[0023] In the figure, there are a skeleton 1, an exchange membrane 2, an outer frame 101, an air duct rib 102, a reinforcing rib 103, a front mold 3 and a rear mold 4. Specific Embodiments

[0024] The present invention will be further described below in conjunction with embodiments.

[0025] Embodiment 1: A preparation method of a total heat exchanger core includes the following steps: Preparing the skeleton rubber compound: Mix 47 parts of homopolypropylene (grade: Y26), 25 parts of block copolymerized polypropylene (grade: 3500), 8 parts of grafting agent (substance: maleic anhydride grafting agent, grade: B1A), 0.4 parts of antioxidant (substances: phosphite antioxidant, hindered amine antioxidant, grades: AT168, AT1010, 0.2 parts each), 0.5 parts of lubricant (substance: polar amide wax, grade: WAX-2120), 0.5 parts of nucleating agent (substance: organic phosphate rigidifying nucleating agent, grade: NP-509), and 0.1 parts of dispersant (substance: linear non-active polydimethylsiloxane, model: 1000CS) by mass, inject the mixture into a screw extruder for melt mixing after uniform mixing, then inject 20.8 parts of glass fiber (particle size range: 13μm) from the feeding port of the screw machine, and extrude the skeleton rubber compound after mixing. The temperature of zone 1 of the screw extruder is 150°C, zone 2 is 230°C, zone 3 is 230°C, zone 4 is 220°C, zone 5 is 220°C, zone 6 is 210°C, zone 7 is 210°C, zone 8 is 210°C, the temperature at the discharge port is 220°C, and the screw speed is 320Hz; Integral injection molding: Place the exchange membrane (PP membrane, thickness 0.02mm) in the membrane cavity of the rear mold 4. There is a water heat exchange structure in the membrane cavity of the rear mold, and the water heat exchange structure exchanges heat with the exchange membrane. Use a clamping force of 12MPa to close the front mold 3 and the rear mold 4. After closing the mold, the gap between the front mold and the exchange membrane is 0.02mm. Start the water heat exchange device to cool the exchange membrane by heat exchange, and then perform injection molding. Inject the skeleton rubber compound into the front mold from the injection pipe of the front mold, and the injection time is 1.5s. During the injection molding process, maintain the temperature of the exchange membrane at 16 - 20°C (the temperature of the heat exchange water is set at 13°C). After the injection molding is completed, cool and form, and open the mold to make the total heat exchanger core.

[0026] A total heat exchanger core as described above, comprising a skeleton 1 and an exchange membrane 2. The thickness of the exchange membrane is 0.02mm. The skeleton includes an outer frame 101 and a number of parallel air duct ribs 102 disposed within the outer frame and compounded with the exchange membrane. The width of the top of the air duct rib from the top to the bottom is 0.6 - 1mm, the height of the air duct rib is 1.8mm, the spacing between adjacent air duct ribs is 5 - 12mm, and adjacent air duct ribs are connected with a reinforcing rib 103.

[0027] Example 2: A preparation method of a total heat exchanger core, comprising the following steps: Preparing the skeleton rubber compound: Mix 45 parts of homopolypropylene (grade: Y26), 23 parts of block copolymerized polypropylene (grade: 3500), 6 parts of grafting agent (substance: maleic anhydride grafting agent, grade: B1A), 0.5 part of antioxidant (substances: phosphite antioxidant, hindered amine antioxidant, grades: AT168, AT1010, 0.25 part each), 0.5 part of lubricant (substance: polar amide wax, grade: WAX - 2120), 0.5 part of nucleating agent (substance: organic phosphate rigidifying nucleating agent, grade: NP - 509), and 0.1 part of dispersant (substance: linear non - active polydimethylsiloxane, model: 1000CS) by mass. After mixing evenly, inject them into a screw extruder for melt mixing. Then, inject 20 parts of glass fiber (particle size range: 13μm) from the feeding port of the screw machine. After mixing and extrusion, the skeleton rubber compound is obtained. The temperature of zone 1 of the screw extruder is 150°C, zone 2 is 230°C, zone 3 is 230°C, zone 4 is 220°C, zone 5 is 220°C, zone 6 is 210°C, zone 7 is 210°C, zone 8 is 210°C, the temperature at the discharge port is 220°C, and the screw speed is 320Hz; Integral injection molding: Place the exchange membrane (PP membrane, thickness 0.02mm) in the membrane cavity of the rear mold 4. There is a water heat exchange structure in the membrane cavity of the rear mold, which conducts heat exchange with the exchange membrane. Use a clamping force of 15MPa to close the front mold 3 and the rear mold 4. After closing the mold, the gap between the front mold and the exchange membrane is 0.01mm. Start the water heat exchange device to cool the exchange membrane by heat exchange, and then perform injection molding. Inject the skeleton rubber compound into the front mold from the injection tube of the front mold, and the injection time is less than 1.5s. During the injection molding process, maintain the temperature of the exchange membrane at 16 - 20°C (the temperature of the heat exchange water is set at 13°C). After the injection molding is completed, cool and form, and then open the mold to make the total heat exchanger core.

[0028] A total heat exchanger core as described above, comprising a skeleton 1 and an exchange membrane 2. The thickness of the exchange membrane is 0.02mm. The skeleton includes an outer frame 101 and a number of parallel air duct ribs 102 disposed within the outer frame and compounded with the exchange membrane. The width of the top of the air duct rib from the top end to the bottom end is 0.6 - 1mm, the height of the air duct rib is 1.5mm, the spacing between adjacent air duct ribs is 5 - 12mm, and adjacent air duct ribs are connected by a reinforcing rib 103.

[0029] Example 3: A method for preparing a total heat exchanger core, comprising the following steps: Preparing the skeletal rubber compound: Mix 49 parts of homopolypropylene (grade: Y26), 27 parts of block copolymerized polypropylene (grade: 3500), 10 parts of grafting agent (substance: maleic anhydride grafting agent, grade: B1A), 1 part of antioxidant (substances: phosphite antioxidant, hindered amine antioxidant, grades: AT168, AT1010), 1 part of lubricant (substance: polar amide wax, grade: WAX - 2120), 1 part of nucleating agent (substance: organic phosphate rigidifying nucleating agent, grade: NP - 509), and 1 part of dispersant (substance: linear non - active polydimethylsiloxane, model: 1000CS) by mass fraction. After mixing evenly, inject them into a screw extruder for melt mixing. Then, inject 21 parts of glass fiber (particle size range: 13μm) from the feeding port of the screw machine. After mixing and extrusion, the skeletal rubber compound is obtained. The temperature of zone 1 of the screw extruder is 150°C, zone 2 is 230°C, zone 3 is 230°C, zone 4 is 220°C, zone 5 is 220°C, zone 6 is 210°C, zone 7 is 210°C, zone 8 is 210°C, the temperature of the discharge port is 220°C, and the screw speed is 320Hz; Integral injection molding: Place the exchange membrane (PP membrane, thickness 0.02mm) in the membrane cavity of the rear mold 4. There is a water heat exchange structure in the membrane cavity of the rear mold, which conducts heat exchange with the exchange membrane. Use a clamping force of 9MPa to close the front mold 3 and the rear mold 4. After closing the mold, the gap between the front mold and the exchange membrane is 0.03mm. Start the water heat exchange device to cool the exchange membrane by heat exchange, and then perform injection molding. Inject the skeletal rubber compound into the front mold from the injection pipe of the front mold, and the injection time is 1.5s. During the injection molding process, maintain the temperature of the exchange membrane at 16 - 20°C (the temperature of the heat exchange water is set at 13°C). After the injection molding is completed, cool and form, and then open the mold to make the total heat exchanger core.

[0030] A total heat exchanger core as described above, comprising a skeleton 1 and an exchange membrane 2. The thickness of the exchange membrane is 0.02mm. The skeleton includes an outer frame 101 and a number of parallel air duct rib strips 102 disposed within the outer frame and compounded with the exchange membrane. The width of the top of the air duct rib strip from the top to the bottom is 0.6 - 1mm, the height of the air duct rib strip is 2mm, the spacing between adjacent air duct rib strips is 5 - 12mm, and adjacent air duct rib strips are connected by a reinforcing rib 103.

[0031] Example 4: A method for preparing a total heat exchanger core, comprising the following steps: Preparing the skeleton rubber compound: Mix 47 parts of homopolypropylene (grade: Y26), 25 parts of block copolymerized polypropylene (grade: 3500), 8 parts of grafting agent (substance: maleic anhydride grafting agent, grade: B1A), 0.5 part of antioxidant (substances: phosphite antioxidant, hindered amine antioxidant, grade: AT168, AT1010), 0.5 part of lubricant (substance: polar amide wax, grade: WAX - 2120), 0.5 part of nucleating agent (substance: organic phosphate rigidifying nucleating agent, grade: NP - 509), and 0.1 part of dispersant (substance: linear non - active polydimethylsiloxane, model: 1000CS) by mass fraction, inject the mixture into a screw extruder after mixing evenly for melt mixing, then inject 20.8 parts of glass fiber (particle size range: 13μm) from the feeding port of the screw machine, and extrude the skeleton rubber compound after mixing. The temperature of zone 1 of the screw extruder is 150°C, zone 2 is 230°C, zone 3 is 230°C, zone 4 is 220°C, zone 5 is 220°C, zone 6 is 210°C, zone 7 is 210°C, zone 8 is 210°C, the temperature of the discharge port is 220°C, and the screw speed is 320Hz; Integral injection molding: Place the exchange membrane (PE membrane, thickness 0.02mm) in the membrane cavity of the rear mold 4. There is a water heat exchange structure in the membrane cavity of the rear mold, which exchanges heat with the exchange membrane. Use a clamping force of 12MPa to close the front mold 3 and the rear mold 4. After closing the mold, the gap between the front mold and the exchange membrane is 0.02mm. Start the water heat exchange device to cool the exchange membrane by heat exchange, and then perform injection molding. Inject the skeleton rubber compound into the front mold from the injection pipe of the front mold, and the injection time is 1.5s. During the injection molding process, maintain the temperature of the exchange membrane at 16 - 20°C (the set temperature of the heat exchange water is 13°C). After the injection molding is completed, cool and form, and open the mold to make the total heat exchanger core.

[0032] A total heat exchanger core as described above, comprising a skeleton 1 and an exchange membrane 2. The thickness of the exchange membrane is 0.02mm. The skeleton includes an outer frame 101 and a number of parallel air duct ribs 102 disposed within the outer frame and compounded with the exchange membrane. The width of the top of the air duct rib from the top to the bottom is 0.6 - 1mm, the height of the air duct rib is 1.8mm, the spacing between adjacent air duct ribs is 5 - 12mm, and adjacent air duct ribs are connected by a reinforcing rib 103.

[0033] Example 5: A preparation method of a total heat exchanger core, comprising the following steps: Preparation of the Skeleton Rubber Compound: Weigh 47 parts of homopolypropylene (grade: Y26), 25 parts of block copolymerized polypropylene (grade: 3500), 8 parts of grafting agent (substance: maleic anhydride grafting agent, grade: B1A), 0.5 part of antioxidant (substances: phosphite antioxidant, hindered amine antioxidant, grade: AT168, AT1010), 0.5 part of lubricant (substance: polar amide wax, grade: WAX - 2120), 0.5 part of nucleating agent (substance: organic phosphate rigidifying nucleating agent, grade: NP - 509), and 0.1 part of dispersant (substance: linear non - reactive polydimethylsiloxane, model: 1000CS) by mass. Mix them evenly and then inject into a screw extruder for melt mixing. Then inject 20.8 parts of glass fiber (particle size range: 13μm) from the feeding port of the screw machine. After mixing and extrusion, the skeleton rubber compound is obtained. The temperature of zone 1 of the screw extruder is 150°C, zone 2 is 230°C, zone 3 is 230°C, zone 4 is 220°C, zone 5 is 220°C, zone 6 is 210°C, zone 7 is 210°C, zone 8 is 210°C, the temperature at the discharge port is 220°C, and the screw speed is 320Hz; Integral Injection Molding: Place the exchange membrane (PP membrane, thickness 0.02mm) in the membrane cavity of the rear mold 4. There is a water heat exchange structure in the membrane cavity of the rear mold, which conducts heat exchange with the exchange membrane. Use a clamping pressure of 12MPa to close the front mold 3 and the rear mold 4. After closing the mold, the gap between the front mold and the exchange membrane is 0.02mm. Start the water heat exchange device to cool the exchange membrane by heat exchange, and then perform injection molding. Inject the skeleton rubber compound into the front mold from the injection tube of the front mold. The injection time is 1.5s. During the injection molding process, maintain the temperature of the exchange membrane at 16 - 20°C (the temperature of the heat exchange water is set at 13°C). After the injection molding is completed, cool and form, and then open the mold to make the total heat exchanger core.

[0034] A total heat exchanger core as described above, comprising a skeleton 1 and an exchange membrane 2. The thickness of the exchange membrane is 0.02mm. The skeleton includes an outer frame 101 and a number of parallel air duct ribs 102 disposed within the outer frame and compounded with the exchange membrane. The width of the air duct ribs from the top to the bottom is 0.6 - 1mm, the height of the air duct ribs is 1.8mm, the spacing between adjacent air duct ribs is 5 - 12mm, and adjacent air duct ribs are connected with reinforcing ribs 103.

[0035] Comparative Example 1: Compared with Example 1, in Comparative Example 1, the rear mold was not subjected to heat exchange treatment, including the following steps: Preparation of the Skeleton Rubber Compound: Weigh 47 parts of homopolypropylene (grade: Y26), 25 parts of block copolymerized polypropylene (grade: 3500), 8 parts of grafting agent (substance: maleic anhydride grafting agent, grade: B1A), 0.5 part of antioxidant (substances: phosphite antioxidant, hindered amine antioxidant, grade: AT168, AT1010), 0.5 part of lubricant (substance: polar amide wax, grade: WAX - 2120), 0.5 part of nucleating agent (substance: organic phosphate rigidifying nucleating agent, grade: NP - 509), and 0.1 part of dispersant (substance: linear non - reactive polydimethylsiloxane, model: 1000CS) by mass fraction. Mix them evenly and then inject into a screw extruder for melt mixing. Then, inject 20.8 parts of glass fiber (particle size range: 13μm) from the feeding port of the screw machine. After mixing and extrusion, the skeleton rubber compound is obtained. The temperature of zone 1 of the screw extruder is 150°C, zone 2 is 230°C, zone 3 is 230°C, zone 4 is 220°C, zone 5 is 220°C, zone 6 is 210°C, zone 7 is 210°C, zone 8 is 210°C, and the temperature at the discharge port is 220°C. The screw speed is 320Hz; Integral Injection Molding: Place the exchange membrane (PP membrane, thickness 0.02mm) in the membrane cavity of the rear mold 4. Use a clamping pressure of 12MPa to close the front mold 3 and the rear mold 4. After closing the mold, the gap between the front mold and the exchange membrane is 0.02mm. Then, carry out injection molding. Inject the skeleton rubber compound into the front mold through the injection pipe of the front mold. The injection time is 1.5s. After the injection molding is completed, cool and form, and then open the mold to make the total heat exchanger core.

[0036] Comparative Example 2: Compared with Example 1, the heat exchange treatment in Comparative Example 2 keeps the temperature of the exchange membrane below the softening point of the exchange membrane, including the following steps: Preparation of the skeleton rubber compound: According to the mass parts, 47 parts of homopolypropylene (grade: Y26), 25 parts of block copolymerized polypropylene (grade: 3500), 8 parts of grafting agent (substance: maleic anhydride grafting agent, grade: B1A), 0.5 part of antioxidant (substances: phosphite antioxidant, hindered amine antioxidant, grades: AT168, AT1010), 0.5 part of lubricant (substance: polar amide wax, grade: WAX - 2120), 0.5 part of nucleating agent (substance: organic phosphate rigidifying nucleating agent, grade: NP - 509), and 0.1 part of dispersant (substance: linear non - active polydimethylsiloxane, model: 1000CS) are mixed evenly and then injected into a screw extruder for melt mixing. Then, 20.8 parts of glass fiber (particle size range: 13μm) are injected from the feeding port of the screw machine. After mixing and extrusion, the skeleton rubber compound is obtained. The temperature of the 1st zone of the screw extruder is 150°C, the 2nd zone is 230°C, the 3rd zone is 230°C, the 4th zone is 220°C, the 5th zone is 220°C, the 6th zone is 210°C, the 7th zone is 210°C, the 8th zone is 210°C, the temperature of the discharge port is 220°C, and the screw speed is 320Hz; Integral injection molding: Place the exchange membrane (PP membrane, thickness 0.02mm) in the membrane cavity of the rear mold 4. The membrane cavity of the rear mold is equipped with a water heat exchange structure, which conducts heat exchange with the exchange membrane. The front mold 3 and the rear mold 4 are clamped with a clamping pressure of 15MPa. After clamping, the gap between the front mold and the exchange membrane is 0.01mm. Start the heat exchange device to cool the exchange membrane by heat exchange, and then perform injection molding. Inject the skeleton rubber compound into the front mold from the injection pipe of the front mold, and the injection time is 1.5s. During the injection molding process, maintain the temperature of the exchange membrane at 100 - 120°C (the temperature of the heat exchange oil is set at 120°C). After the injection molding is completed, cool and form, and then open the mold to make the total heat exchanger core.

[0037] Comparative Example 3: Compared with Example 1, in Comparative Example 3, the heat exchange treatment keeps the temperature of the exchange membrane below the temperature tolerance of the surface coating of the exchange membrane, including the following steps: Preparing the Skeleton Rubber Compound: Mix 47 parts of homopolypropylene (grade: Y26), 25 parts of block copolymerized polypropylene (grade: 3500), 8 parts of grafting agent (substance: maleic anhydride grafting agent, grade: B1A), 0.5 part of antioxidant (substances: phosphite antioxidant, hindered amine antioxidant, grades: AT168, AT1010), 0.5 part of lubricant (substance: polar amide wax, grade: WAX - 2120), 0.5 part of nucleating agent (substance: organic phosphate rigidifying nucleating agent, grade: NP - 509), and 0.1 part of dispersant (substance: linear non - active polydimethylsiloxane, model: 1000CS) by mass fraction, then inject the mixture into a screw extruder for melt mixing. Next, inject 20.8 parts of glass fiber (particle size range: 13 microns) from the feeding port of the screw machine. After mixing and extrusion, the skeleton rubber compound is obtained. The temperature of the 1st zone of the screw extruder is 150°C, the 2nd zone is 230°C, the 3rd zone is 230°C, the 4th zone is 220°C, the 5th zone is 220°C, the 6th zone is 210°C, the 7th zone is 210°C, the 8th zone is 210°C, the temperature at the discharge port is 220°C, and the screw speed is 320Hz; Integral Injection Molding: Place the exchange membrane (PP membrane, thickness 0.02mm) in the membrane cavity of the rear mold 4. There is a water heat exchange structure in the membrane cavity of the rear mold, which exchanges heat with the exchange membrane. Use a clamping pressure of 12MPa to close the front mold 3 and the rear mold. After closing the mold, the gap between the front mold and the exchange membrane is 0.02mm. Start the water heat exchange device to cool the exchange membrane by heat exchange, and then perform injection molding. Inject the skeleton rubber compound into the front mold from the injection pipe of the front mold, and the injection time is 1.5s. During the injection molding process, maintain the temperature of the exchange membrane at 70 - 80°C (the temperature of the heat exchange water is set at 80°C). After the injection molding is completed, cool and form, and then open the mold to make the total heat exchanger core.

[0038] Comparative Example 4: Compared with Example 1, in Comparative Example 4, the temperature of the exchange membrane during the heat exchange treatment is too low, including the following steps: Preparing the skeleton rubber compound: Mix 47 parts of homopolypropylene (grade: Y26), 25 parts of block copolymerized polypropylene (grade: 3500), 8 parts of grafting agent (substance: maleic anhydride grafting agent, grade: B1A), 0.5 part of antioxidant (substances: phosphite antioxidant, hindered amine antioxidant, grade: AT168, AT1010), 0.5 part of lubricant (substance: polar amide wax, grade: WAX-2120), 0.5 part of nucleating agent (substance: organic phosphate rigidifying nucleating agent, grade: NP-509), and 0.1 part of dispersant (substance: linear non-active polydimethylsiloxane, model: 1000CS) evenly by mass, then inject the mixture into a screw extruder for melt mixing. Next, inject 20.8 parts of glass fiber (particle size range: 13 microns) from the feeding port of the screw machine. After mixing and extrusion, the skeleton rubber compound is obtained. The temperature of zone 1 of the screw extruder is 150°C, zone 2 is 230°C, zone 3 is 230°C, zone 4 is 220°C, zone 5 is 220°C, zone 6 is 210°C, zone 7 is 210°C, zone 8 is 210°C, the temperature of the discharge port is 220°C, and the screw speed is 320 Hz; Integral injection molding: Place the exchange membrane (PP membrane, thickness 0.02 mm) in the membrane cavity of the rear mold 4. There is a water heat exchange structure in the membrane cavity of the rear mold, and the water heat exchange structure exchanges heat with the exchange membrane. Use a clamping pressure of 12 MPa to close the front mold 3 and the rear mold 4. After closing the mold, the gap between the front mold and the exchange membrane is 0.02 mm. Start the water heat exchange device to cool the exchange membrane by heat exchange, and then perform injection molding. Inject the skeleton rubber compound into the front mold from the injection pipe of the front mold, and the injection time is 1.5 s. During the injection molding process, maintain the temperature of the exchange membrane at 5 - 8°C (the temperature of the heat exchange water is set at 3°C). After the injection molding is completed, cool and form, and then open the mold to make the total heat exchanger core.

[0039] Comparative Example 5: Compared with Example 1, in Comparative Example 5, the gap between the front mold and the exchange membrane is too large, with a gap of 0.05 mm, and it includes the following steps: Prepare the skeleton rubber compound: According to the mass parts, 47 parts of homopolypropylene (grade: Y26), 25 parts of block copolymerized polypropylene (grade: 3500), 8 parts of grafting agent (substance: maleic anhydride grafting agent, grade: B1A), 0.5 part of antioxidant (substances: phosphite antioxidant, hindered amine antioxidant, grade: AT168, AT1010), 0.5 part of lubricant (substance: polar amide wax, grade: WAX-2120), 0.5 part of nucleating agent (substance: organic phosphate rigidifying nucleating agent, grade: NP-509), and 0.1 part of dispersant (substance: linear non-active polydimethylsiloxane, model: 1000CS) are mixed evenly and then injected into a screw extruder for melt mixing. Then, 20.8 parts of glass fiber (particle size range: 13 microns) are injected from the feeding port of the screw machine, and after mixing and extrusion, the skeleton rubber compound is obtained. The temperature of the 1st zone of the screw extruder is 150 °C, the 2nd zone is 230 °C, the 3rd zone is 230 °C, the 4th zone is 220 °C, the 5th zone is 220 °C, the 6th zone is 210 °C, the 7th zone is 210 °C, the 8th zone is 210 °C, the temperature of the discharge port is 220 °C, and the screw speed is 320 Hz; Integral injection molding: Place the exchange membrane (PP membrane, thickness 0.02 mm) in the membrane cavity of the rear mold 4. There is a water heat exchange structure in the membrane cavity of the rear mold, and the water heat exchange structure conducts heat exchange on the exchange membrane. The front mold 3 and the rear mold are clamped with a clamping pressure of 6 MPa. After clamping, the gap between the front mold and the exchange membrane is 0.1 mm. Start the water heat exchange device to cool the exchange membrane by heat exchange, and then perform injection molding. Inject the skeleton rubber compound into the front mold from the injection pipe of the front mold, and the injection time is 30 s. During the injection molding process, maintain the temperature of the exchange membrane at 16 - 20 °C (the temperature of the heat exchange water is set at 13 °C). After the injection molding is completed, cool and form, and then open the mold to make the total heat exchanger core.

[0040] Comparative Example 6: Compared with Example 1, in Comparative Example 6, the skeleton rubber compound uses ABS (ABS-121H Ningbo Yongxing), and it includes the following steps: Place the exchange membrane (PP membrane, thickness 0.02 mm) in the membrane cavity of the rear mold 4. The front mold 3 and the rear mold are clamped with a clamping pressure of 12 MPa. After clamping, the gap between the front mold and the exchange membrane is 0.02 mm. Perform injection molding. Inject the skeleton rubber compound into the front mold from the injection pipe of the front mold, and the injection time is 6.5 s. During the injection molding process, maintain the temperature of the exchange membrane at 16 - 20 °C (the temperature of the heat exchange water is set at 13 °C). After the injection molding is completed, cool and form, and then open the mold to make the total heat exchanger core.

[0041] Detection Example: The skeleton impact strength, the composite strength between the exchange membrane and the skeleton, the thickness of the air duct rib, and the heat exchange efficiency of the total heat exchanger cores prepared in Examples 1 to 5 and Comparative Examples 1 to 6 were tested; The structural strength test method was carried out with reference to the method disclosed in "ISO 180 / 1eA Cantilever Beam Notch Impact Strength"; The test method for the composite strength between the exchange membrane and the skeleton was carried out using a tensiometer; The heat exchange efficiency was tested with reference to the method disclosed in "GB-T 21087-2020 Heat Recovery Fresh Air Units"; The test results are shown in Table 1.

[0042] Table 1 Test Results As shown in Table 1, the heat exchange efficiency of the total heat exchanger cores prepared in Examples 1 to 5 was 67-68.5%, the skeleton impact strength was 10-12 kJ / m2, and the composite strength between the exchange membrane and the skeleton was 24.05-26.59 N. The above results show that the total heat exchanger cores prepared by the present invention have excellent skeleton impact strength, composite strength, and heat exchange efficiency.

[0043] In Comparative Example 1, the exchange membrane was not heat-treated. It was found that the shape of the exchange membrane of the total heat exchanger core prepared in Comparative Example 1 changed and could not be used.

[0044] In Comparative Example 2, the temperature of the heat exchange membrane was controlled below the softening point of the heat exchange membrane. It was found that the shape of the exchange membrane of the total heat exchanger core prepared in Comparative Example 2 did not change, but the coating on the surface of the exchange membrane was damaged, and the function of the exchange membrane to isolate gas was damaged and could not be applied.

[0045] In Comparative Example 3, the temperature of the heat exchange membrane was controlled below the coating tolerance temperature. It was found that the shape of the exchange membrane of the total heat exchanger core prepared in Comparative Example 3 did not change and the surface coating was not damaged, but the shape of the air duct rib prepared at this temperature changed greatly. A part of the width of the air duct rib compounded with the surface of the exchange membrane was larger, and the interface of the air duct rib formed an inverted T shape, resulting in a significant increase in the coverage area of the air duct rib on the exchange membrane and significantly reducing the exchange efficiency of the exchange membrane per unit time.

[0046] In Comparative Example 4, the temperature of the heat exchange membrane was controlled too low. It was found that when the skeleton adhesive had not yet contacted the exchange membrane, the skeleton adhesive had already started to solidify, resulting in the inability to form a composite between the skeleton adhesive and the exchange membrane. By analyzing the results of Example 1 and Comparative Examples 1 to 4, it was found that controlling the temperature during the heat treatment of the heat exchange membrane has an important impact. Reasonable temperature control can ensure the effective combination of the exchange membrane and the skeleton and form air duct ribs with a stable shape and a thin thickness.

[0047] In Comparative Example 5, the gap between the front mold and the exchange membrane was explored. It was found that when the gap between the front mold and the exchange membrane was enlarged to 0.1 mm, the cross-section of the air duct rib formed would also be an inverted T shape, resulting in a significant reduction in the exchange efficiency of the exchange membrane per unit time. After analysis, the present invention believes that when the temperature of the exchange membrane and the gap between the front mold and the exchange membrane are appropriate, the rubber compound will quickly solidify the rubber compound between the exchange membrane and the front mold after contacting the exchange membrane, so that the rubber compound will not undergo obvious shape changes, thereby ensuring that the formed air duct rib will not overly cover the surface of the exchange membrane, and the composite can be completed, ensuring that the thickness of the air duct rib is thinner.

[0048] In Comparative Example 6, the skeleton was prepared using ABS material. As a result, it was found that the ABS material could not complete injection molding, and the composite strength between the formed skeleton and the exchange membrane was only 3.68 N. In addition, through calculation, it was found that the minimum thickness of the air duct rib formed by injection molding using ABS could only reach 2 - 2.5 mm, and the unit heat exchange efficiency of the total heat exchanger core was only 30.65%. Compared with Examples 1 to 5, the heat exchange performance and composite strength of the total heat exchanger core in Comparative Example 6 were significantly reduced.

[0049] The above are only the preferred embodiments of the present invention, and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent transformations made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a total heat exchanger core, characterized in that: The following steps are involved: The full heat exchanger core is prepared using the front mold and the rear mold, the exchange membrane is placed in the mold cavity of the rear mold, the rear mold is molded with the front mold, the skeleton raw material is melted to make a skeleton rubber compound, and then the skeleton rubber compound is injected into the front mold for injection molding, and the rear mold performs heat exchange treatment on the exchange membrane, and the heat exchange treatment maintains the exchange membrane temperature at 16~20 ℃.

2. The preparation method according to claim 1, characterized in that: The skeleton raw materials include, by weight: 45-49 parts of homopolymer polypropylene, 23-27 parts of block copolymer polypropylene, 6-10 parts of grafting agent, 0.5-1 part of antioxidant, 0.5-1 part of lubricant, 0.5-1 part of nucleating agent, 0.1-1 part of dispersant, and 20-21 parts of glass fiber.

3. The preparation method according to claim 1, characterized in that: The heat exchange process adopts liquid heat exchange.

4. The preparation method according to claim 1, characterized in that: After the membrane is closed, the gap between the front mold and the exchange membrane is 0.01~0.03 mm.

5. The preparation method according to claim 1, characterized in that: The injection molding time is ≤3s and the total molding cycle time is ≤70s.

6. A total heat exchanger core, characterized in that: The invention comprises a skeleton (1) and an exchange membrane (2) composited on the skeleton, wherein the skeleton comprises an outer frame (101) and a plurality of air duct ribs (102) arranged on the outer frame, and the full heat exchanger core is manufactured by the manufacturing method according to any one of claims 1 to 5.

7. The total heat exchanger core according to claim 6, characterized in that: The air duct ribs and adjacent air duct ribs are connected with reinforcing ribs (103).

8. The total heat exchanger core according to claim 6 or 7, characterized in that: The width of the air duct ribs is 0.6-1 mm.

9. The total heat exchanger core according to claim 6 or 7, characterized in that: The height of the air duct ribs is 1.5-2 mm.

10. The total heat exchanger core according to claim 6, characterized in that: The exchange membrane is one of a PP membrane and a PE membrane.

Images