A method of foaming an insulation layer

Abstract

A method for foaming an insulation layer includes the following steps: continuously or intermittently arranging several elongated foaming cavities within a foaming space; injecting foaming material into the foaming cavities; when the foaming cavities are intermittently arranged, continuing to inject foaming material into the gaps between adjacent foaming cavities; and expanding and solidifying the foaming material to form an insulation layer. This invention distributes the foaming material within multiple elongated spaces for expansion and foaming. The elongated spaces facilitate the rapid upward movement of the foaming material, resulting in a more uniform foaming density. This avoids uneven foaming density caused by the foaming material spreading outwards or the first-foamed material enveloping the unfoamed material, leading to a higher density at the bottom and a lower density at the top. Furthermore, foaming within elongated spaces eliminates the outward diffusion force, making the foaming process closer to free foaming, thereby reducing the overall average foaming density, and consequently reducing the consumption of foaming material and lowering costs.

Description

Technical Field

[0001] This invention belongs to the field of electrical insulation layer technology, specifically relating to a foaming method for insulation layers of household appliances. Background Technology

[0002] Appliances such as water heaters, refrigerators, and freezers typically require insulation layers. Currently, these layers are generally formed using a one-time injection molding process. For larger appliances, such as water heaters, due to their height, the foaming space is large, and a large amount of foaming material is needed. However, since the foaming machine injects the material from a single inlet, the injection time is relatively long due to the limitations of the machine's foaming speed. For example... Figure 1 As shown ( Figure 1 The slashed filler in the image represents the foaming material. The first foaming material injected will foam and diffuse outwards. This diffusion reduces the foaming material's climbing ability, and the diffused foaming material will surround the unfoamed foaming material injected later, increasing foaming resistance, making foaming difficult, slowing volume growth, and leading to increased foaming material density and consumption. Furthermore, due to the height of the water heater, the injected foaming material falls to the bottom under gravity. The greater the pressure at the bottom, the greater the density difference between the top and bottom, which also leads to increased foaming material consumption. In addition, the inner tank surface of the water heater is usually coated with enamel or other anti-corrosion materials. After spraying anti-corrosion materials, the inner tank surface is relatively rough, with a frosted feel. This roughness also hinders the flow of the foaming material, reducing its fluidity and thus increasing the amount of foaming material used. Summary of the Invention

[0003] The purpose of this invention is to provide a foaming method for insulation layers that produces uniform foam density and reduces costs by lowering the average foam density.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A method for foaming an insulation layer includes the following steps:

[0006] Several narrow, elongated foaming cavities are arranged continuously or at intervals within the foaming space;

[0007] Foaming material is injected into the foaming cavity; when the foaming cavities are spaced apart, foaming material is continued to be injected into the gaps between adjacent foaming cavities; the foaming material expands and solidifies to form an insulation layer.

[0008] In the above-described insulation layer foaming method, optionally, the foaming cavity is a flexible foaming cavity.

[0009] Furthermore, the cross-sectional area of ​​the foaming cavity is 2000 mm². 2 ~5000mm 2 ;

[0010] And / or, the wall thickness of the foaming cavity is 0.01 to 0.1 mm;

[0011] And / or, the cross-sectional shape of the foaming cavity is circular, elliptical, or polygonal.

[0012] Furthermore, the foaming cavity is a polymer film bag, and the polymer film material is PET, PVC, PE, PP, or PE-HD.

[0013] Furthermore, when the foaming chambers are spaced apart, the foaming method is as follows:

[0014] Foaming material is injected into the foaming cavity;

[0015] A small amount of foaming material is injected into the gap between adjacent foaming cavities;

[0016] After the small amount of foaming material injected into the bottom of the gap has solidified, continue to inject foaming material into the gap between adjacent foaming cavities.

[0017] Furthermore, a vacuum nozzle located at the opening end of the foaming cavity is used to fix the foaming cavity.

[0018] Furthermore, a bag body support is used to fix the foaming cavity. The bag body support includes several bag opening fixing rings for installing the foaming cavity. The bag opening fixing rings are fixed on the support body composed of an outer ring and an inner ring.

[0019] When preparing the insulation layer between the inner tank and the outer shell of a water heater, the diameter of the outer ring corresponds to the inner diameter of the outer shell of the water heater, and the outer ring can be placed inside the outer shell. The diameter of the inner ring corresponds to the outer diameter of the inner tank of the water heater, and the inner ring can be fitted over the inner tank.

[0020] Optionally, when the foaming cavities are continuously arranged, the foaming method for the insulation layer described above is as follows:

[0021] Foaming material is injected into the foaming cavity at intervals of one cavity.

[0022] After the foaming material that was injected first has solidified, the remaining foaming material is injected into the foaming cavity.

[0023] Furthermore, a sponge pad is provided at the bottom of the foaming space. After the foaming material expands and foams in the foaming cavity, the bottom of the foaming cavity and the sponge pad are squeezed and sealed.

[0024] Optionally, in the above-described method for foaming the insulation layer, adjacent foaming cavities are connected as a single unit, and the foaming method is as follows:

[0025] Foaming material is injected into the foaming cavity in sequence;

[0026] Alternatively, foaming material can be injected into the foaming cavities in a manner that alternates between foaming cavities. After the first foaming material has solidified, foaming material can be injected into the remaining foaming cavities.

[0027] In the above-described insulation layer foaming method, optionally, the foaming cavity is a rigid foaming cavity.

[0028] Furthermore, the cross-sectional area of ​​the foaming cavity is 2000 mm². 2 ~7500mm 2 ;

[0029] And / or, the wall thickness of the foaming cavity is 1.0 to 1.5 mm.

[0030] Furthermore, the foaming cavity is made of PS, PVC, or PU.

[0031] Furthermore, when the foaming chambers are spaced apart, the foaming method is as follows:

[0032] Foaming material is injected into the foaming cavity;

[0033] A small amount of foaming material is injected into the gap between adjacent foaming cavities;

[0034] After the small amount of foaming material injected into the bottom of the gap has solidified, continue to inject foaming material into the gap between adjacent foaming cavities.

[0035] Furthermore, when the foaming cavities are continuously arranged, the foaming method is as follows: foaming material is injected into the foaming cavities sequentially, or foaming material is injected into the foaming cavities in a manner that skips one foaming cavity, and then foaming material is injected into the remaining foaming cavities.

[0036] Furthermore, adjacent foaming cavities are connected as one unit.

[0037] In the insulation layer foaming method described above, the foaming density of the insulation layer is 27.5–30 kg / m³. 3 Its strength is 150–205 kPa.

[0038] As can be seen from the above technical solutions, the foaming method of the present invention changes the traditional foaming process of injection molding at one point. It distributes the foaming material in multiple narrow spaces for expansion and foaming. The narrow spaces are conducive to the rapid upward movement of the foaming material, resulting in a more uniform foaming density. This avoids the uneven foaming density caused by the foaming material spreading and flowing in all directions, or the foaming material wrapping around the unfoamed foaming material. The bottom density is high and the top density is low. Moreover, foaming in narrow spaces eliminates the divergent force that spreads in all directions, making the foaming process closer to free foaming. This reduces the overall average foaming density, which in turn reduces the consumption of foaming material and thus reduces costs.

[0039] In some embodiments, the foaming cavity is made of stretched polymer material with a very smooth surface, which can reduce the flow resistance of foaming and facilitate the rapid rise of the foaming material, ensuring uniform foaming density and consistent insulation layer strength.

[0040] In some embodiments, the foaming cavity can be a regular shape such as round or square, and can be used in the production of regular foamed space insulation layers, such as between the inner tank and outer shell of a water heater, the inside of the door panel of a refrigerator, the inside of the cabinet panel of a freezer, etc.

[0041] The insulation layer prepared using the foaming method of this invention will not exhibit a high density at the bottom and a low density at the top. It will have a uniform foam density distribution and consistent strength, with a foam density ranging from 27.5 to 30 kg / m³. 3 The strength is between 150 and 205 kPa, meeting the requirements for insulation layers in household appliances.

[0042] Moreover, the foaming cavity of the present invention has a certain strength. When the foaming material is squeezed from above, the pressure will increase to a certain extent due to the constraint of the foaming cavity. Attached Figure Description

[0043] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 A schematic diagram of the diffusion of foaming materials in existing foaming processes;

[0045] Figure 2 This is a schematic diagram of the diffusion of the foaming material in the foaming cavity according to the method of the present invention;

[0046] Figure 3 A schematic diagram showing the installation of an insulation layer between the inner tank and the outer shell of a water heater;

[0047] Figure 4 This is a schematic diagram illustrating the placement of the foaming chamber between the inner tank and outer shell of a water heater according to an embodiment of the present invention;

[0048] Figure 5 This is a simplified schematic diagram of the flexible foaming cavity disposed between the inner tank and the outer shell of a water heater according to Embodiment 1 of the present invention;

[0049] Figure 6 This is a schematic diagram of the structure of the bag support in Embodiment 3 of the present invention;

[0050] Figure 7 This is a schematic diagram of the flexible foaming cavity mounted on the bag support in Embodiment 3 of the present invention;

[0051] Figure 8 This is a simplified schematic diagram of the flexible foaming cavity disposed between the inner tank and the outer shell of a water heater according to Embodiment 4 of the present invention;

[0052] Figure 9 This is a schematic diagram of the foaming chamber structure in Embodiment 5 of the present invention;

[0053] Figure 10 This is a top view of the foaming cavity in Embodiment 5 of the present invention.

[0054] Explanation of icon numbers

[0055] 100—Inner liner; 200—Outer shell; 300—Flexible foam cavity

[0056] 400—Vacuum nozzle; 500—Bag body support; 501—Bag opening fixing ring

[0057] Outer Ring Road - 502 Inner Ring Road - 503

[0058] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Detailed Implementation

[0059] The present invention will now be described in detail with reference to the accompanying drawings. In the detailed description of the embodiments of the present invention, for ease of explanation, the drawings illustrating the device structure will be partially enlarged without adhering to the general scale. Furthermore, the schematic diagrams are merely examples and should not be construed as limiting the scope of protection of the present invention. It should be noted that the drawings are in a simplified form and use non-precise scales, solely for the purpose of conveniently and clearly illustrating the embodiments of the present invention. Additionally, in the description of this application, terms such as "first" and "second" are used only to distinguish descriptions and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Terms such as "positive," "negative," "bottom," "upper," and "lower" indicate orientation or positional relationships based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0060] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0061] Many electrical appliances incorporate insulation layers, which are formed by the expansion of foamed materials. Polyurethane foam is a common type of foamed material used for insulation. For example, polyurethane foam in its free-expansion state has a foam density of 20–30 kg / m³. 3 When using traditional foaming processes to foam polyurethane foam in corresponding locations in appliances such as water heaters, the foaming density of polyurethane foam in the mold (the mold refers to the foaming space of the foaming material, such as the space between the inner tank and outer shell of a water heater, the internal space of a refrigerator door, the internal space of a freezer panel, etc., where insulation material needs to be filled) is 45-55 kg / m³. 3 The foam density is much higher than that in the free-foaming state. If the foam density of the foam material in the mold can be reduced to be close to that in the free-foaming state, the foaming cost can be reduced.

[0062] To address the problems of existing large-scale foaming processes where the foaming material reacts rapidly and diffuses outwards during injection, resulting in low foaming height, uneven foaming density (high density at the bottom, low density at the top), and high consumption of foaming material, this invention proposes an improved foaming process. This invention replaces the existing single-point injection method with a multi-space foaming approach, using multiple elongated foaming cavities. An elongated foaming cavity is defined as one whose length is at least twice its width.

[0063] like Figure 2 As shown ( Figure 2 The slanted filled portion (representing the foaming material) in this invention involves injecting the foaming material into a narrow, elongated foaming cavity. The cavity's specific shape guides the material's expansion. Constrained by the narrow cavity, the material flows upwards only from the bottom, eliminating outward diffusion and allowing it to rise higher and faster. This prevents diffusion, which reduces the material's rising ability, and avoids the situation where diffused material surrounds unfoamed material, increasing foaming resistance, making foaming difficult, and leading to higher material density. The foaming is more uniform. Furthermore, because the material rises rapidly within the cavity, the foaming process is close to free foaming, reducing density and ensuring more uniform distribution. This avoids a situation where the bottom density is high and the top density is low, reducing material consumption and thus lowering costs.

[0064] The foaming cavity of this invention can be a flexible foaming cavity, such as one made of a polymer film material. The surface of the polymer film material is smooth and has low resistance, allowing the foaming material to expand rapidly within the foaming cavity. This reduces the average foaming density of the foaming space while maintaining the foaming strength.

[0065] In practical applications, polymer film materials can be made into long, strip-shaped bags to serve as flexible foaming cavities. Foaming material is then injected into the bags for foaming. The polymer film materials used to prepare the flexible foaming cavities can be PET, PVC, PE, PP, PE-HD, etc. These polymer film materials are characterized by easy stretching and high toughness.

[0066] To prevent the foam material from spreading outwards during foaming in the foaming cavity, the cross-sectional area of ​​the foaming cavity should not be too large. Moreover, since the flexible foaming cavity is made of thin film material, if the cross-sectional area of ​​the foaming cavity is too large, more foam material is required. The more foam material at the same height, the greater the foaming pressure, which can easily lead to film rupture. At the same time, if the cross-sectional area of ​​the foaming cavity is too small, the expansion rate of the foam material is fast, resulting in greater pressure on the sides of the foaming cavity, which can also easily lead to film rupture.

[0067] Therefore, optionally, the cross-sectional area of ​​the flexible foam cavity can be 2000 mm². 2 ~5000mm 2 The cross-sectional shape of the flexible foam cavity can be circular, elliptical, or polygonal, such as square, trapezoidal, or hexagonal. When the cross-sectional shape of the foam cavity is circular, the diameter of the foam cavity is preferably 66±10mm.

[0068] The wall thickness of the flexible foam cavity can be 0.01–0.1 mm. When used in the insulation layer of water heaters, the wall thickness of the flexible foam cavity is preferably 0.03 mm. This thickness ensures the strength of the film bag and prevents it from breaking during the foaming process. Furthermore, excessive thickness will increase the thermal conductivity of the film bag and reduce its insulation performance.

[0069] When using thin film materials to prepare a flexible foam cavity in the shape of a bag, one end of the foam cavity is sealed, which can be done twice with a sealing machine to ensure a sealing effect and prevent the foam material from expanding and opening the first sealing line. The other end of the foam cavity is not sealed, and the foam material is injected from the open end.

[0070] The foaming cavity of this invention can also be a rigid foaming cavity. The material of the rigid foaming cavity can be porous plastic, such as PS, PVC, PU, ​​etc., which can ensure thermal insulation performance. The wall thickness of the rigid foaming cavity can be 1.0 to 1.5 mm.

[0071] Rigid foam cavities have thicker walls than flexible foam cavities, so they can withstand greater foaming pressure. Therefore, the cross-sectional area of ​​rigid foam cavities can be slightly larger.

[0072] Optionally, the cross-sectional area of ​​the rigid foam cavity can be 2000 mm². 2 ~7500mm 2 In other words, the cross-sectional area of ​​the rigid foam cavity can be 1 to 1.5 times that of the flexible foam cavity. The cross-sectional area of ​​the rigid foam cavity should also not be too large. If the cross-sectional area is too large, that is, the internal space of the foam cavity is too large, the effect of reducing the foam density will be relatively worse, and it is easy to deform under the expansion force of the foam material.

[0073] The length of the foaming cavity can be adjusted according to actual usage, and is generally less than or equal to the length of the product's foaming space, but should not exceed 2 meters. If the length of the foaming cavity is too long, the foaming material may not have completely descended to the bottom of the cavity before foaming begins, resulting in low foam density at the bottom, uneven foam density, and inconsistent thermal insulation performance.

[0074] The foaming process of the present invention includes the following steps:

[0075] Several narrow, elongated foaming cavities are placed continuously or intermittently within the foaming space;

[0076] Foaming material is injected into the foaming cavity, and the foaming material rises from the bottom of the foaming cavity to foam.

[0077] When the foaming chambers are spaced apart, meaning there are gaps between adjacent foaming chambers, foaming material is continuously injected into the gaps between adjacent foaming chambers. The foaming material rises from the bottom of the gap and foams upwards. After the foaming material expands and solidifies, it forms an insulation layer.

[0078] The present invention will be further described below through specific embodiments. Unless otherwise specified, the materials and equipment used in the following description are all conventional materials and equipment, and are commercially available.

[0079] Example 1

[0080] The foaming cavity in this embodiment is a flexible foaming cavity, specifically a long strip of plastic bag made of PE-HD. PE-HD material has good toughness, good tensile strength, and is inexpensive. This embodiment uses the production of the insulation layer of a water heater as an example to illustrate the foaming method of the present invention. The insulation layer of the water heater is located between the inner tank and the outer shell of the water heater.

[0081] The foaming material used in this embodiment can be a safe and environmentally friendly cyclopentane-based foaming material. In other embodiments, one or more foaming materials selected from 245fa, n-, isopentane, 365mfa, and butane can also be used. 141b foaming material has good foaming performance, but its environmental performance is poor, and it is generally not used for insulation layers in household appliances.

[0082] like Figure 3 As shown, an insulation layer needs to be installed between the inner tank 100 and the outer shell 200 of the water heater. Foamed material is injected between the inner tank 100 and the outer shell 200, and the foamed material expands to form the insulation layer. In this embodiment, the foaming cavity is a long, narrow plastic bag with a circular cross-section. The length of the foaming cavity is no greater than the height of the water heater's inner tank. If the length of the foaming cavity is greater than the height of the water heater's inner tank (the length of the insulation layer), the foaming cavity will bend during the foaming process, causing deformation of the foaming voids and affecting subsequent foaming.

[0083] The inner tank 100 of the water heater is suspended inside the outer casing 200 with the bottom cover installed, and its position is adjusted to be centered. The foaming method of this embodiment includes the following steps:

[0084] S1. Flexible foaming cavities 300 are inserted intermittently in the space between the inner tank 100 and the outer shell 200 of the water heater, such as... Figure 4As shown; there is a gap between adjacent flexible foaming cavities 300, and the cross-sectional area of ​​the gap is less than or equal to the cross-sectional area of ​​the flexible foaming cavity 300; in order to avoid frequent adjustment of the injection volume of the foaming machine, the cross-sectional area of ​​the gap between the flexible foaming cavities 300 can be comparable to the cross-sectional area of ​​the flexible foaming cavity, or slightly smaller than the cross-sectional area of ​​the flexible foaming cavity.

[0085] S2. Inject foaming material into the flexible foaming cavity; such as Figure 5 As shown, Figure 5 A simplified diagram illustrating the flexible foaming cavity positioned between the inner tank and outer shell of a water heater. Figure 5 The numbers 1, 3, 5, 7, ... represent flexible foaming cavities, and 2, 4, 6, 8, ... represent the gaps between adjacent flexible foaming cavities. The foaming machine injects foaming material into the flexible foaming cavities 1, 3, 5, 7, ..., so that each flexible foaming cavity is filled with foaming material. The foaming material reaches the bottom of the flexible foaming cavity under the action of gravity, and then foams and fills the flexible foaming cavity.

[0086] S3. A small amount of foaming material is injected into the gaps 2, 4, 6, 8, ... between adjacent flexible foaming cavities. The foaming material falls under the action of gravity and fills the gap between the bottom of the flexible foaming cavities 1, 3, 5, 7, ... and the bottom cover of the outer shell 200. After the foaming material expands, it comes into contact with the bottom of the flexible foaming cavities 1, 3, 5, 7, ... Thus, the gaps 2, 4, 6, 8, ... between the flexible foaming cavities also form independent spaces, similar to long and narrow foaming cavities, which are not interconnected. In this way, the foaming material cannot flow from one gap to another.

[0087] The small amount of foaming material mentioned here refers to the amount of foaming material that is injected, which is only enough to fill the space between the flexible foam cavity and the bottom cover of the outer shell. The specific amount will vary depending on the size and structure of the actual product, and is not limited here.

[0088] S4. After the small amount of foamed material injected to the bottom of the gap has solidified, continue injecting foamed material into the gaps 2, 4, 6, 8, ... between adjacent flexible foamed cavities, so that the foamed material fills the gaps 2, 4, 6, 8, ... The foamed material expands and foams from bottom to top in the gaps 2, 4, 6, 8, ... between adjacent flexible foamed cavities. After the flexible foamed cavities and the gaps between adjacent flexible foamed cavities are filled with foamed material, an insulation layer is formed between the inner liner and the outer shell.

[0089] Example 2

[0090] Based on Example 1, such as Figure 4As shown, in this embodiment, a pair of vacuum nozzles 400 are provided at the open end of each flexible foaming cavity 300. The two vacuum nozzles 400, which are arranged opposite each other, clamp the flexible foaming cavity 300, thereby fixing the flexible foaming cavity 300 and ensuring that the open end of the flexible foaming cavity 300 remains open during the foaming material injection process, facilitating the injection of foaming material. On the other hand, fixing the flexible foaming cavity 300 with the vacuum nozzles 400 can prevent the foaming material ejected from the foaming machine during injection from impacting the flexible foaming cavity 300, causing the flexible foaming cavity 300 to fall into the outer shell 200 and affect foaming.

[0091] In practical applications, the vacuum nozzle can be fixed to the nozzle holder (not shown). The nozzle holder has a suspension part and a clamp to hold the vacuum nozzle, similar to the structure of a clothes rack. As long as it can help fix the vacuum nozzle to the open end of the flexible foam cavity, it is sufficient.

[0092] Example 3

[0093] When the flexible foaming cavity is a thin film plastic bag made of polymer material, in order to facilitate fixing the flexible foaming cavity in the foaming space, such as fixing it between the inner tank and the outer shell of the water heater, this embodiment uses a bag support 500 to install the flexible foaming cavity 300 to improve work efficiency.

[0094] Based on Example 1, such as Figure 6 As shown, the bag support 500 includes several bag opening fixing rings 501 for installing flexible foaming cavities. The bag opening fixing rings 501 are fixed at intervals on the support body composed of an outer ring 502 and an inner ring 503. The diameter of the outer ring 502 corresponds to the inner diameter of the water heater shell, so that the outer ring 502 can be inserted into the water heater shell. The diameter of the inner ring 503 corresponds to the outer diameter of the inner tank, so that the inner ring 503 can be fitted onto the outside of the inner tank. Thus, the bag support 500 can be fixedly installed between the inner tank and the outer shell of the water heater.

[0095] The diameter of the bag opening fixing ring 501 is set to correspond to the diameter of the flexible foam cavity 300, such as... Figure 7 As shown, the open end of the flexible foaming cavity 300 is fixed together with the bag mouth fixing ring 501. The bag mouth fixing ring 501 plays a role in fixing the flexible foaming cavity 300. When the bag body support 500 is installed at the top between the inner tank and the outer shell of the water heater, the flexible foaming cavity is also installed in the space between the inner tank and the outer shell of the water heater. The operation is simple and quick.

[0096] The foaming method in this embodiment includes the following steps:

[0097] S1. Insert the flexible foaming cavity 300 between the inner tank and the outer shell of the water heater;

[0098] S2. First, inject foaming material into the flexible foaming cavity 300;

[0099] S3. Then, inject a small amount of foam material into the gap between adjacent flexible foam materials to fix the bottom of the flexible foam cavity 300 and the bottom of the outer shell.

[0100] S4. Then, inject foam material into the gap between adjacent flexible foam cavities 300. The foam material expands and solidifies to form an insulation layer.

[0101] When injecting foaming material, the foaming material can be injected into each foaming cavity simultaneously, or it can be injected into each foaming cavity sequentially.

[0102] Similarly, foaming material can be injected into each gap simultaneously, or it can be injected into each gap sequentially.

[0103] Example 4

[0104] The difference between this embodiment and Embodiment 1 is that in this embodiment, the flexible foaming cavities are continuously placed within the foaming space, with no gaps between adjacent flexible foaming cavities. This embodiment will still be described using the example of setting an insulation layer between the inner tank and the outer shell of a water heater.

[0105] The inner liner is suspended inside the outer shell with the bottom cover installed, and its position is adjusted to ensure that the inner liner is centered. The foaming method in this embodiment includes the following steps:

[0106] S1. A flexible foaming cavity is placed in the space between the inner tank and the outer shell of the water heater, and the flexible foaming cavities are placed continuously adjacent to each other;

[0107] S2. Inject foam material into the flexible foam cavity at intervals of one flexible foam cavity; such as... Figure 8 As shown, first inject foaming material into flexible foaming cavities 1, 3, 5, 7, ..., and do not inject foaming material into flexible foaming cavities 2, 4, 6, 8, ... between flexible foaming cavities 1 and 3, 3 and 5, 5 and 7, ...;

[0108] S3. After the previously injected foam material has expanded and solidified, inject more foam material into the remaining flexible foam cavities 2, 4, 6, 8, ... The foam material expands and solidifies to form an insulation layer.

[0109] Because the material of the flexible foam cavity has tensile and extensible properties, after the foam material is injected, the flexible foam cavity can deform with the expansion of the foam material, so that the foam material can fill the space between adjacent flexible foam cavities, as well as the space between the flexible foam cavity and the inner liner outer wall and the outer shell inner wall.

[0110] In this embodiment, a sponge pad is provided at the bottom of the space between the outer shell and the inner liner (foaming space). The bottom of the flexible foaming cavity is in contact with the sponge pad. After the foaming material is cured, the bottom of the flexible foaming cavity can be squeezed and sealed with the sponge pad.

[0111] The flexible foam cavity in this embodiment can be fixed using the vacuum nozzle of Embodiment 2 or the bag support of Embodiment 3. When the bag support of Embodiment 3 is used, the bag opening fixing rings on the bag support are also continuously arranged, rather than spaced out, corresponding to the flexible foam cavity.

[0112] Example 5

[0113] like Figure 9 and Figure 10 In this embodiment, adjacent foaming cavities are integrated into a single unit, manufactured using a one-piece molding process, with the foaming cavities connected sequentially. Each foaming cavity has a fan-shaped cross-section, and these consecutive fan-shaped foaming cavities are connected to form a hollow tubular body with a circular cross-section. The tubular body is placed between the inner tank and outer shell of the water heater, and foaming material is then injected into the foaming cavities.

[0114] The foaming method in this embodiment includes the following steps:

[0115] S1. Foaming chambers are inserted intermittently in the space between the inner tank and the outer shell of the water heater;

[0116] S2. Inject foaming material into the foaming cavity; In this embodiment, the adjacent foaming cavities are connected as one unit. Therefore, when injecting foaming material, it can be injected into the foaming cavity sequentially, or it can be injected into the foaming cavity by injecting foaming material at intervals of one foaming cavity. After the foaming material injected first expands and solidifies, foaming material is injected into the remaining foaming cavities.

[0117] The foaming cavity in this embodiment can be a flexible foaming cavity or a rigid foaming cavity. When it is a rigid foaming cavity, since the rigid foaming cavity itself has a certain hardness and strength, the foaming cavity itself can serve as an outer shell, making it suitable for the production of insulation layers that do not require other outer shells.

[0118] Example 6

[0119] The foaming cavity in this embodiment is a rigid foaming cavity, which can be placed at intervals within the foaming space. The foaming steps in this case are basically the same as those in Embodiment 1, and the steps are as follows:

[0120] First, inject the foaming material into the foaming cavity;

[0121] Then, foaming material is injected into the gaps between adjacent foaming cavities so that the foaming material can fill the entire foaming space.

[0122] The foaming cavities can also be placed continuously within the foaming space. Since the rigid foaming cavity itself has a certain hardness and strength, it can maintain its shape. In this case, the foaming steps can be to inject foaming material into each foaming cavity in sequence, or to inject foaming material into the foaming cavity by injecting foaming material into the foaming cavity at intervals of one foaming cavity, and then inject foaming material into the remaining foaming cavity.

[0123] The insulation layer prepared using the foaming method of this invention, because the foaming material foams within a narrow, elongated space, the foaming process can be approximated as free foaming. Therefore, compared to traditional foaming processes, the foam density can be effectively reduced by approximately 30%. The foam density of the insulation layer prepared using the foaming method of this invention is 27.5–30 kg / m³. 3 The corresponding strength is 150-205 kPa, which fully meets the requirements for insulation layers in electrical appliances such as water heaters. Because the foam density is reduced, the amount of foaming material consumed is also reduced, thus achieving the goal of cost reduction.

[0124] When the shape of the foaming space changes, the arrangement of the foaming cavities can also change accordingly. As in the previous embodiment, the foaming cavities are used for the foaming of the insulation layer between the inner tank and outer shell of a water heater, therefore they are arranged in a circular shape. When applied to foaming spaces with a rectangular cross-sectional shape, such as refrigerator door panels, the foaming cavities can be placed in the foaming space along a straight line. The shape and arrangement of the foaming cavities can vary according to the shape of the actual foaming space used, and are not limited here.

[0125] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for foaming an insulation layer, characterized in that, Includes the following steps: Several narrow, elongated foaming cavities are arranged continuously or at intervals within the foaming space; Foaming material is injected into the foaming cavity; when the foaming cavities are spaced apart, foaming material is continuously injected into the gaps between adjacent foaming cavities. After the foaming material injected into the bottom of the gap has solidified, foaming material is continuously injected into the gaps between adjacent foaming cavities. When the foaming cavities are continuously arranged, foaming material is injected into the foaming cavities at intervals of one foaming cavity. After the foaming material injected first has solidified, foaming material is injected into the remaining foaming cavities. The foamed material expands and solidifies to form an insulation layer.

2. The method for foaming the insulation layer as described in claim 1, characterized in that: The foaming cavity is a flexible foaming cavity.

3. The method for foaming the insulation layer as described in claim 2, characterized in that: The cross-sectional area of ​​the foaming cavity is 2000 mm². 2 ~5000mm 2 ; And / or, the wall thickness of the foaming cavity is 0.01 to 0.1 mm; And / or, the cross-sectional shape of the foaming cavity is circular, elliptical, or polygonal.

4. The method for foaming the insulation layer as described in claim 2, characterized in that: The foaming cavity is a polymer film bag, and the polymer film material is PET, PVC, PE, PP, or PE-HD.

5. The method for foaming the insulation layer as described in claim 2, characterized in that: The foaming cavity is fixed using a vacuum nozzle located at the opening end of the foaming cavity.

6. The method for foaming the insulation layer as described in claim 2, characterized in that: The foaming cavity is fixed using a bag body bracket, which includes several bag opening fixing rings for installing the foaming cavity. The bag opening fixing rings are fixed to the bracket body composed of an outer ring and an inner ring. When preparing the insulation layer between the inner tank and the outer shell of a water heater, the diameter of the outer ring corresponds to the inner diameter of the outer shell of the water heater, and the outer ring is placed inside the outer shell. The diameter of the inner ring corresponds to the outer diameter of the inner tank of the water heater, and the inner ring is fitted over the inner tank.

7. The method for foaming the insulation layer as described in claim 1, characterized in that: When the foaming chambers are continuously arranged, a sponge pad is provided at the bottom of the foaming space. After the foaming material expands and foams in the foaming chamber, the bottom of the foaming chamber and the sponge pad are squeezed and sealed.

8. The method for foaming the insulation layer as described in claim 2, characterized in that: When the foaming chambers are arranged continuously, adjacent foaming chambers are connected as one unit. The foaming method is as follows: foaming material is injected into the foaming chambers in sequence.

9. The method for foaming the insulation layer as described in claim 1, characterized in that: The foaming cavity is a rigid foaming cavity.

10. The method for foaming the insulation layer as described in claim 9, characterized in that: The cross-sectional area of ​​the foaming cavity is 2000 mm². 2 ~7500mm 2 ; And / or, the wall thickness of the foaming cavity is 1.0 to 1.5 mm.

11. The method for foaming the insulation layer as described in claim 9, characterized in that: The foaming cavity is made of PS, PVC, or PU.

12. The method for foaming the insulation layer as described in claim 9, characterized in that: When the foaming chambers are continuously arranged, the foaming method is as follows: foaming material is sequentially injected into the foaming chambers.

13. The method for foaming the insulation layer as described in claim 12, characterized in that: The adjacent foaming cavities are connected as one unit.

14. The method for foaming the insulation layer as described in claim 1, characterized in that: The foaming density of the insulation layer is 27.5–30 kg / m³. 3 Its strength is 150–205 kPa.

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