Foaming method and foaming apparatus

Abstract

The application relates to a freezing equipment technology and provides a foaming method and a foaming equipment. The foaming method comprises the following steps: keeping the flow of foaming material constant; keeping the size of a discharging port of a mixing bin constant, so that the initial landing position of the foaming material on a back plate of a box body is stopped for a first predetermined time length; adjusting the size of the discharging port, so that the intermediate landing position of the foaming material changes along a predetermined route; keeping the size of the discharging port constant, so that the terminal landing position of the foaming material on the back plate is stopped for a second predetermined time length. The flow rate of the foaming material is changed by adjusting the size of the discharging port of the mixing bin under the condition that the flow of the foaming material is constant, then the change of the landing position of the foaming material is controlled, the purpose of directional enrichment of the foaming material in a cavity is achieved, the uniformity or non-uniformity of the distribution of the foaming material is artificially controlled, the covering area of the foaming material is increased, the flow time and distance of the foaming material are reduced, the injection efficiency is improved due to single injection, and the production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration equipment, and in particular to a foaming method and foaming equipment. Background Art

[0002] The performance and process of refrigerator foam determine the quality of refrigerator performance. There are two main types of existing refrigerator foaming processes. One is to assemble the outer shell and the inner liner to form a pre-assembled box, and to form a filling cavity between the outer wall of the inner liner and the outer shell. The foaming material is injected into the filling cavity. After the injection is completed, the back panel of the box is closed. This foaming process has the following problems: the back panel is closed after the injection is completed, which affects the foaming efficiency; the equipment changes are large and the technical transformation cost is high. The other is to inject the foaming material into the mold cavity multiple times, with each injection landing point being different, and the foaming material expands until it fills the mold. This foaming process has the following problems: multiple injections affect the injection efficiency; the variable flow injection process is used, which places high demands on the foaming equipment and the injection cost is high. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a foaming method that utilizes the flow rate of the foaming material to control the change in the foaming material landing point, thereby increasing the coverage area of ​​the foaming material, reducing the foaming material flow time, reducing production costs, and improving the uniformity or unevenness of the foaming material distribution.

[0004] The present invention also provides a foaming device.

[0005] According to the foaming method of the first embodiment of the present invention, the foaming method comprises the following steps:

[0006] Keep the flow of foaming material constant;

[0007] Maintaining a constant size of the discharge port of the mixing bin so that the foaming material remains at an initial landing position on the back panel of the box for a first predetermined period of time;

[0008] Adjusting the size of the discharge port so that the middle landing point of the foaming material changes along a predetermined route;

[0009] The size of the discharge port is maintained constant so that the foaming material stops at the final landing point on the back plate for a second predetermined period of time.

[0010] According to the foaming method of an embodiment of the present invention, the flow rate of the foaming material is changed by adjusting the size of the discharge port of the mixing bin while the flow rate of the foaming material is constant, thereby controlling the change in the landing position of the foaming material, and combining the control of the pause time of the landing position of the foaming material to achieve the purpose of directional enrichment of the foaming material in the mold cavity, artificially control the uniformity or unevenness of the distribution of the foaming material, increase the coverage area of ​​the foaming material, reduce the flow time of the foaming material, and reduce production costs.

[0011] According to one embodiment of the present application, the adjusting the size of the outlet comprises:

[0012] If the average thickness of the foaming layer is less than L, and the injection time is less than the creaming time of the foaming material, the cleaning piston is driven to move away from the nozzle of the foaming gun body, so as to increase the size of the outlet;

[0013] Or, if the average thickness of the foaming layer is greater than L, and the injection time is less than the creaming time of the foaming material, the cleaning piston is driven to move close to the nozzle of the foaming gun body, so as to decrease the size of the outlet;

[0014] Or, if the injection time is greater than the creaming time of the foaming material, the cleaning piston is driven to move close to the nozzle of the foaming gun body first, and then move away from the nozzle of the foaming gun body, so as to decrease the size of the outlet first and then increase the size of the outlet.

[0015] According to one embodiment of the present application, the dwell time of each intermediate landing point of the foaming material is equal or partially equal.

[0016] According to one embodiment of the present application, the initial landing point position and the final landing point position are the same position, or are different positions on the same straight line.

[0017] According to one embodiment of the present application, the box comprises a refrigerator shell and a refrigerator liner arranged inside the refrigerator shell, and a cavity for accommodating the foaming material is formed between the refrigerator shell and the refrigerator liner.

[0018] According to the foaming device of the second embodiment of the present application, the foaming device comprises:

[0019] The foaming gun comprises a foaming gun body and a mixing bin arranged on one side of the foaming gun body, an internal flow channel is formed in the foaming gun body, an outlet of the mixing bin is in communication with the flow channel, an inlet of the mixing bin is in communication with the feeding system, a valve body is arranged in the flow channel, the valve body is adapted to change the flow rate of the foaming material by changing the size of the outlet, and then change the landing point position of the foaming material.

[0020] According to one embodiment of the present application, further comprising:

[0021] A driving system connected with the valve body, the valve body being a cleaning piston in sliding fit with the flow channel, the driving system being adapted to drive the cleaning piston to move along the axial direction of the flow channel;

[0022] A control system electrically connected with the driving system;

[0023] An adjusting system electrically connected with the control system and the feeding system, respectively.

[0024] According to one embodiment of the present invention, the further embodiment includes:

[0025] A precise feedback system is electrically connected to the control system. The precise feedback system is arranged in the drive system and is suitable for sensing the distance that the drive system drives the cleaning piston to move.

[0026] According to one embodiment of the present invention, the driving system is a hydraulic system, and the cleaning piston rod of the hydraulic system is connected to the cleaning piston.

[0027] According to one embodiment of the present invention, the control system is a PLC control system, the adjustment system is a frequency converter, and the feeding system is a feeding pump.

[0028] The above one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0029] According to the foaming method of an embodiment of the present invention, the flow rate of the foaming material is changed by adjusting the size of the discharge port of the mixing bin when the flow rate of the foaming material is constant, thereby controlling the change of the landing position of the foaming material, and combining the pause time control of the landing position of the foaming material to achieve the purpose of directional enrichment of the foaming material in the mold cavity, artificially control the uniformity or unevenness of the distribution of the foaming material, increase the coverage area of ​​the foaming material, and reduce the flow time and distance of the foaming material. Since it is a single injection, the injection efficiency is improved and the production cost is reduced.

[0030] Furthermore, according to the foaming equipment of the embodiment of the present invention, the flow rate of the foaming material is changed by adjusting the size of the discharge port of the mixing bin while the flow rate of the foaming material is constant, thereby controlling the change of the landing position of the foaming material, and combining the pause time control of the landing position of the foaming material to achieve the purpose of directional enrichment of the foaming material in the mold cavity, artificially control the uniformity or unevenness of the distribution of the foaming material, increase the coverage area of ​​the foaming material, and reduce the flow time and distance of the foaming material. Since it is a single injection, the injection efficiency is improved and the production cost is reduced.

[0031] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 This is one of the flow diagrams of the foaming method provided in an embodiment of the present invention;

[0034] Figure 2 This is the second flow chart of the foaming method provided in an embodiment of the present invention;

[0035] Figure 3 This is the third flow chart of the foaming method provided in an embodiment of the present invention;

[0036] Figure 4 This is the fourth flow chart of the foaming method provided in an embodiment of the present invention;

[0037] Figure 5 This is one of the schematic diagrams of the placement of the foaming material on the back plate provided in an embodiment of the present invention;

[0038] Figure 6 This is the second schematic diagram of the location of the foaming material on the back plate provided in an embodiment of the present invention;

[0039] Figure 7 This is one of the structural diagrams of the foaming gun provided by an embodiment of the present invention;

[0040] Figure 8 This is the second structural schematic diagram of the foaming gun provided in an embodiment of the present invention.

[0041] Reference numerals:

[0042] 100. Foaming gun; 110. Mixing chamber; 111. Foaming gun body; 120. Discharge port; 130. Cleaning piston; 140. Initial landing point; 150. Final landing point; 160. Box body; 200. Foaming material. DETAILED DESCRIPTION

[0043] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0044] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0045] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on the specific circumstances.

[0046] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," or "above" a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," or "below" a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0047] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0048] Figure 1 One of the flow diagrams of the foaming method provided by an embodiment of the present invention is illustrated, as shown in FIG. Figure 1 As shown, the foaming method comprises the following steps:

[0049] Step a10, maintaining the flow rate of the foaming material 200 constant;

[0050] Step a20, maintaining a constant size of the discharge port 120 of the mixing bin 110 so that the foaming material 200 pauses at the initial landing position 140 on the back plate of the box body 160 for a first predetermined time;

[0051] Step a30, adjusting the size of the discharge port 120 so that the middle landing point of the foaming material 200 changes along a predetermined route;

[0052] Step a40, keep the size of the discharge port 120 constant, so that the end point landing position 150 of the foaming material 200 on the back plate stops for a second predetermined time length.

[0053] According to the foaming method of the embodiment of the present application, by adjusting the size of the discharge port 120 of the mixing bin 110 to change the flow rate of the foaming material 200 when the flow of the foaming material 200 is constant, the change of the landing position of the foaming material 200 is controlled, and the purpose of directional enrichment of the foaming material 200 in the cavity is achieved in combination with the landing position stopping time control of the foaming material 200, the uniformity or non-uniformity of the distribution of the foaming material 200 is artificially controlled, the coverage area of the foaming material 200 is increased, and the flow time and distance of the foaming material 200 are reduced. Since it is a single injection, the injection efficiency is improved, and the production cost is reduced.

[0054] According to the embodiment of the present application, Figure 5 One of the foaming material 200 landing position schematic diagram on the back plate provided by the embodiment of the present application is illustrated, Figure 6 The second foaming material 200 landing position schematic diagram on the back plate provided by the embodiment of the present application is illustrated, Figure 7 The structure schematic diagram of the foaming gun provided by the embodiment of the present application is illustrated, Figure 8 The structure schematic diagram of the foaming gun provided by the embodiment of the present application is illustrated; as Figures 5 to 8 As shown, adjusting the size of the discharge port 120 includes the following three cases:

[0055] The first case is that the average thickness of the foaming layer is less than L, and the injection time length is less than the creaming time length of the foaming material 200, and the cleaning piston 130 is driven to move away from the nozzle of the foaming gun body 111.

[0056] Due to the structural difference of the box body 160, the landing position change scheme of the foaming material 200 needs to be set in advance according to the structure of the box body 160, and the average size of the flow channel inside the box body 160 determines the average thickness of the foaming layer, so the landing position change scheme of the foaming material 200 is determined according to the average thickness of the foaming layer and / or the injection time length during implementation. As Figure 6 and Figure 8 As shown, in the case where the average thickness of the foaming layer is less than L and the injection time length is less than the creaming time length of the foaming material 200, the cleaning piston 130 is driven to move away from the nozzle of the foaming gun body 111. At this time, the size of the discharge port 120 of the mixing bin 110 is increased, and since the flow of the foaming material 200 input into the mixing bin 110 is constant, the flow rate of the foaming material 200 is reduced, and the distance from the landing position of the foaming material 200 to the foaming gun 100 gradually decreases.

[0057] The existing single-gun injection foaming process is not suitable for the foaming needs of large-volume boxes, ultra-thin refrigerators and boxes with special-shaped structures, while the foaming method of the embodiment of the present application increases the coverage area of the foaming material 200 by changing the falling point of the foaming material 200, reduces the flow time and distance of the foaming material 200, improves the injection efficiency due to single injection, and reduces the production cost. At the same time, by taking advantage of the low viscosity and strong flowability of the starting end of the foaming material 200, the narrow runner or special-shaped structure design is preferentially filled, thereby reducing the use amount of the foaming material 200 on the basis of ensuring sufficient filling.

[0058] The second case is that the average thickness of the foaming layer is greater than L, and the injection time is less than the creaming time of the foaming material 200, and the cleaning piston 130 is driven to move towards the direction close to the nozzle of the foaming gun body 111.

[0059] As shown in Figure 5 and Figure 7 , in the case where the average thickness of the foaming layer is greater than L and the injection time is less than the creaming time of the foaming material 200, the cleaning piston 130 is driven to move towards the direction close to the nozzle of the foaming gun body 111. At this time, the size of the discharge port 120 of the mixing bin 110 is reduced, and since the flow of the foaming material 200 input into the mixing bin 110 is constant, the flow rate of the foaming material 200 increases, and the distance from the falling point position of the foaming material 200 to the foaming gun 100 gradually increases.

[0060] As shown in Figure 5 and Figure 6 , the black dots represent the falling point positions of the foaming material 200, and the dashed lines represent the coverage range of each foaming material 200 at the falling point position. The foaming material 200 flows in liquid state to the surrounding, so that the coverage range increases.

[0061] The existing multiple injection process is to inject the foaming material 200 into the mold cavity in multiple times, and the falling point is different each time, so that the foaming material 200 enters each area and expands until the mold is filled. However, this foaming process needs to be completed by multiple injections, which seriously affects the injection efficiency. The foaming method of the embodiment of the present application increases the coverage area of the foaming material 200 by changing the falling point of the foaming material 200, reduces the flow time and distance of the foaming material 200, and improves the injection efficiency and reduces the production cost compared with the multiple injection foaming process. At the same time, by taking advantage of the low viscosity and strong flowability of the starting end of the foaming material 200, the narrow runner or special-shaped structure design is preferentially filled, thereby reducing the use amount of the foaming material 200 on the basis of ensuring sufficient filling.

[0062] It should be noted that since the average size of the runner of each type of box 160 is different, the average thickness of the foaming layer is also different, so the specific vertical of L is determined according to the average size of the runner of the box.

[0063] In the third case, the injection time is longer than the milky time of the foaming material 200 , and the cleaning piston 130 is driven to move toward the muzzle of the foaming gun body 111 first, and then move away from the muzzle of the foaming gun body 111 .

[0064] When the injection time is longer than the milky white duration of the foaming material 200, the cleaning piston 130 is driven to first move toward the muzzle of the foaming gun body 111, and then move away from the muzzle of the foaming gun body 111. This causes the landing point of the foaming material 200 to first move away from the foaming gun 100 and then toward the foaming gun 100, forming a reciprocating injection process. Because the injection time is longer than the milky white duration of the foaming material 200, the flow properties of the foaming material 200 deteriorate. By repeatedly changing the landing point of the foaming material 200, the low viscosity and high flow properties of the foaming material 200 at the starting point of the subsequent injection are fully utilized, reducing the amount of foaming material 200 used while ensuring sufficient filling.

[0065] According to an embodiment of the present invention, the pause duration at each intermediate landing point of the foaming material 200 is equal or partially equal. When the pause duration at each intermediate landing point of the foaming material 200 is equal, the intermediate landing points of the foaming material 200 change uniformly, that is, the distance between the landing point of the foaming material 200 and the foaming gun 100 changes uniformly. When the pause duration at the intermediate landing points of the foaming material 200 is partially equal, the intermediate landing points of the foaming material 200 change non-uniformly, that is, the distance between the landing point of the foaming material 200 and the foaming gun 100 also changes non-uniformly.

[0066] According to an embodiment of the present invention, housing 160 comprises a refrigerator outer shell and a refrigerator liner disposed within the outer shell. A cavity is formed between the outer shell and the liner to accommodate foam material 200. The foam material 200 within the cavity determines the performance of the refrigerator. The foaming method of this embodiment of the present invention increases the coverage area of ​​foam material 200 and reduces the flow time and distance of foam material 200, thereby reducing refrigerator production costs and increasing product competitiveness.

[0067] It should be noted here that the foaming method of the embodiment of the present invention can be used not only in the production process of refrigerators, but also in other production processes that require a foaming process.

[0068] According to an embodiment of the present invention, the length of the box 160 is 1700 mm, where L = 15 mm. Because the initial drop point 140 and the final drop point 150 are related to the length of the box 160, when the length of the box 160 changes, the initial drop point 140 and the final drop point 150 also change. Of course, the determination of the initial drop point 140 and the final drop point 150 also needs to take into account the fluidity of the foaming material 200 and the structure of the box 160.

[0069] According to one embodiment of the present invention, the final landing point 150 and the initial landing point 140 can be located at the same position. This situation is suitable for a reciprocating injection method, that is, the landing point of the foaming material 200 first leaves the initial landing point 140, then returns to the initial landing point 140 after a period of movement, and the intermediate landing point and the initial landing point 140 are located on the same straight line. Of course, the final landing point 150 and the initial landing point 140 can also be located at different positions on the same straight line. This situation is suitable for the movement of the foaming material 200 from far to near or from near to far relative to the foaming gun 100. In this case, because the angle of the foaming gun 100 does not change, the final landing point 150 and the initial landing point 140 remain on the same straight line even when the flow rate of the foaming material 200 changes.

[0070] According to an embodiment of the present invention, Figure 2 The second flow chart of the foaming method provided by the embodiment of the present invention is illustrated as follows: Figure 2 As shown, before injection, the foam material 200's landing point variation is pre-set based on the cabinet 160 structure. The refrigerator's top uses a VIP panel, the average flow channel size is 10mm-15mm, and the cabinet 160 is 1700mm long. Based on the cabinet 160 structure, the foam material 200's landing point range is determined to be 300mm-1200mm. The injection time is 5 seconds, which is less than the foam material 200's milky white duration. During injection, follow these steps:

[0071] Step b10, maintaining the flow rate of the foaming material 200 constant;

[0072] Step b20, maintaining the size of the discharge port 120 of the mixing bin 110 constant so that the initial landing point of the foaming material 200 pauses for 0.5s at 1200mm;

[0073] Here, 1200mm is the initial landing point 140, and a pause of 0.5s at 1200mm is used to preferentially fill the narrow flow channel at the top.

[0074] Step b30, driving the cleaning piston 130 to move away from the muzzle of the foaming gun body 111, so that the middle landing point of the foaming material 200 changes along a predetermined route;

[0075] When the cleaning piston 130 is driven to move away from the muzzle of the foaming gun body 111, the size of the discharge port 120 of the mixing chamber 110 increases. Since the flow rate of the foaming material 200 entering the mixing chamber 110 is constant, the flow rate of the foaming material 200 decreases, and the distance between the landing point of the foaming material 200 and the foaming gun 100 gradually decreases, and all the landing points of the foaming material 200 are located on the same straight line. As the intermediate landing points change along the predetermined route, the pause duration of each intermediate landing point of the foaming material 200 is equal or partially equal.

[0076] Step b40: maintaining the size of the discharge port 120 constant so that the final landing point of the foaming material 200 pauses at 450 mm for 0.5-1.0 s.

[0077] The foam material 200 pauses at the final landing point of 450mm for 0.5-1.0s to fill the space at the bottom. It should be noted that the pause time at the initial landing point of 1200mm is not limited to 0.5s and is determined by the structure of the box 160 and the fluidity of the foam material 200. The pause time at the final landing point of 450mm is not limited to 0.5-1.0s and is determined by the structure of the box 160 and the fluidity of the foam material 200.

[0078] According to an embodiment of the present invention, Figure 3 The third flow chart of the foaming method provided by the embodiment of the present invention is illustrated as follows: Figure 3 As shown, before injection, the foam material 200's landing point variation is pre-set based on the structure of the refrigerator housing 160. The refrigerator bottom uses a VIP plate, the average flow channel size is 15mm-30mm, and the length of the refrigerator housing 160 is 1700mm. Based on the structure of the refrigerator housing 160, the foam material 200's landing point range is determined to be 350mm-1200mm. The injection time is 5 seconds, which is less than the time it takes for the foam material 200 to become milky white. During injection, follow these steps:

[0079] Step c10, maintaining the flow rate of the foaming material 200 constant;

[0080] Step c20, maintaining a constant size of the discharge port 120 of the mixing bin 110 so that the initial landing point of the foaming material 200 pauses for 1.0-2.0 seconds at a position of 350 mm to 400 mm;

[0081] Here, 350mm-400mm is the initial landing point position 140, and a pause of 1.0-2.0s at 350mm-400mm is used to preferentially fill the narrow flow channel at the bottom. Since the bottom cavity is larger, the pause time is slightly longer.

[0082] Step c30, driving the cleaning piston 130 to move toward the muzzle of the foaming gun body 111, so that the middle landing point of the foaming material 200 changes along a predetermined route;

[0083] When the cleaning piston 130 is driven to move towards the nozzle of the foaming gun body 111, the size of the discharge port 120 of the mixing bin 110 is reduced, and since the flow of the foaming agent 200 input into the mixing bin 110 is constant, the flow rate of the foaming agent 200 is increased, the distance from the falling point position of the foaming agent 200 to the foaming gun 100 is gradually increased, and all the falling point positions of the foaming agent 200 are on the same straight line. During the change of the intermediate falling point position along the predetermined route, the stop time of each intermediate falling point of the foaming agent 200 is equal or partially equal.

[0084] Step c40, keep the size of the discharge port 120 constant, so that the terminal falling point of the foaming agent 200 at 1200mm stops for 0.5-1.0s.

[0085] The terminal falling point of the foaming agent 200 at 1200mm stops for 0.5-1.0s, which is used to fill the top foaming layer, the top exhaust is poor, and the foaming agent 200 needs to be gathered. It should be noted here that the stop time of the initial falling point at 350mm-400mm is not limited to 1.0-2.0s, and is determined according to the structure of the box body 160 and the flowability of the foaming agent 200. The stop time of the terminal falling point of the foaming agent 200 at 1200mm is not limited to 0.5-1.0s, and is determined according to the structure of the box body 160 and the flowability of the foaming agent 200.

[0086] According to the embodiment of the present application, Figure 4 The fourth flowchart of the foaming method provided by the embodiment of the present application is illustrated as follows: Figure 4 As shown in the figure, the falling point change scheme of the foaming agent 200 is set in advance according to the structure of the box body 160 before injection, the average size of the flow channel is 15mm, that is, the average thickness of the foaming layer is 15mm, and the length of the box body 160 is 1700mm. According to the structure of the box body 160, the falling point of the foaming agent 200 is determined to change reciprocatingly in the range of 400mm-1200mm, that is, 400mm-1200mm-400mm, and the injection time is 10s, which is longer than the creaming time of the foaming agent 200. The injection is carried out according to the following steps:

[0087] Step d10, keep the flow of the foaming agent 200 constant;

[0088] Step d20, keep the size of the discharge port 120 of the mixing bin 110 constant, so that the initial falling point of the foaming agent 200 at 400mm stops for 1.0-1.5s;

[0089] In step d30, the cleaning piston 130 is driven to move toward the muzzle of the foaming gun body 111 so that the landing point of the foaming material 200 moves to 1000 mm, and pauses at 1000 mm for 1.5-2.0 seconds. The cleaning piston 130 is then driven to move away from the muzzle of the foaming gun body 111 so that the landing point of the foaming material 200 moves to 400 mm.

[0090] The cleaning piston 130 is driven to move first toward the muzzle of the foaming gun body 111, then away from the muzzle. This causes the foaming material 200 to first land away from the foaming gun 100 and then move closer to it, thus forming a reciprocating injection process. When the injection duration is longer than the milky white duration of the foaming material 200, the flow properties of the foaming material 200 deteriorate. By repeatedly changing the landing point of the foaming material 200, the low viscosity and high flow properties of the foaming material 200 at the starting point of the subsequent injection are fully utilized, reducing the amount of foaming material 200 used while ensuring sufficient filling. As the intermediate landing point position changes along the predetermined route, the pause duration of the foaming material 200 at each intermediate landing point is equal or partially equal.

[0091] Step d40, maintaining the size of the discharge port 120 constant so that the final landing point of the foaming material 200 pauses at 400 mm for 1.0-1.5 seconds.

[0092] The foaming method of the embodiment of the present invention is particularly effective for improving the box 160 with a long injection time and a large injection volume. By regulating the movement speed of the foaming material 200 landing point or adopting a reciprocating injection scheme, the purpose of uniform injection of the gun head is achieved, avoiding secondary injection. For special box structures, it is preferred to set a starting drop point locally, and then move the foaming material 200 landing point after the special structure is completely filled, so as to reduce premature injection or secondary foaming. Special box structures suitable for the foaming method of the embodiment of the present invention include but are not limited to: box structures with a relatively large length and width (a length-to-width ratio of more than 3.5), single-gun injection at the bottom of an ultra-thin refrigerator (or a local thickness of the foaming layer of less than 10 mm), a box structure with a large difference in the volume of the upper and lower cavities of the box 160, and a narrow local foaming layer on the injection path.

[0093] It should be noted that the landing point of the foaming material 200 described above is based on the foaming gun 100 as a reference.

[0094] The present invention also provides a foaming device, such as Figure 7 and Figure 8As shown, the foaming equipment includes a foaming gun 100, which includes a foaming gun body 111 and a mixing chamber 110. The mixing chamber 110 is arranged on one side of the foaming gun body 111. A flow channel is formed inside the foaming gun body 111. The discharge port 120 of the mixing chamber 110 is connected to the flow channel, and the feed port of the mixing chamber 110 is connected to the feeding system. A valve body is provided in the flow channel, and the valve body is suitable for changing the flow rate of the foaming material 200 by changing the size of the discharge port 120, thereby changing the landing position of the foaming material 200.

[0095] According to the foaming equipment of an embodiment of the present invention, the flow rate of the foaming material 200 is changed by adjusting the size of the discharge port 120 of the mixing bin 110 while the flow rate of the foaming material 200 is constant, thereby controlling the change in the landing position of the foaming material 200, and combining the control of the pause time of the landing position of the foaming material 200 to achieve the purpose of directional enrichment of the foaming material 200 in the mold cavity, artificially regulating the uniformity or unevenness of the distribution of the foaming material 200, increasing the coverage area of ​​the foaming material 200, and reducing the flow time and distance of the foaming material 200. Since it is a single injection, the injection efficiency is improved and the production cost is reduced.

[0096] It should be noted that the bottom plate of the refrigerator is provided with a material injection hole, through which the muzzle of the foaming gun enters the interior of the box body 160. When injecting material, the refrigerator is placed horizontally, that is, the back plate is placed downward and the front plate is placed upward, so that the foaming material 200 falls on the back plate.

[0097] According to an embodiment of the present invention, the foaming device further includes a control system, a regulating system, and a drive system, wherein the drive system is connected to the valve body, which is a cleaning piston 130 that slides with the flow channel, and the drive system is suitable for driving the cleaning piston 130 to move along the axial direction of the flow channel. The drive system is electrically connected to the control system, and the regulating system is electrically connected to the control system and the feeding system, respectively. It should be noted here that the type of valve body is not limited to the cleaning piston 130, but can also be a spiral valve body. When the valve body is a spiral valve body, the drive system adjusts the size of the discharge port 120 by driving the spiral valve body to rotate.

[0098] According to an embodiment of the present invention, the foaming apparatus further includes a precise feedback system, the control system being electrically connected to the precise feedback system, and the precise feedback system being disposed within the drive system. The precise feedback system is adapted to sense the distance traveled by the drive system driving the cleaning piston 130. The precise feedback system may be a position sensor or a distance sensor. The precise feedback system is intended to precisely control the distance traveled by the cleaning piston 130, thereby precisely controlling the landing point of the foaming material 200, thereby achieving targeted enrichment of the foaming material 200 within the mold cavity, artificially controlling the uniformity or unevenness of the distribution of the foaming material 200, and reducing the amount of foaming material 200 used.

[0099] According to an embodiment of the present invention, the driving system is a hydraulic system, and a piston rod of the hydraulic system is connected to the cleaning piston 130 .

[0100] According to an embodiment of the present invention, the control system is a PLC control system, the regulating system is a frequency converter, and the feeding system is a feeding pump.

[0101] According to an embodiment of the present invention, Figure 7 and Figure 8 As shown, the foaming equipment includes a foaming gun 100, a control system, an adjustment system, a drive system and a precise feedback system. The foaming gun 100 includes a foaming gun body 111 and a mixing chamber 110. The mixing chamber 110 is arranged on one side of the foaming gun body 111. A flow channel for the foaming material 200 to flow is formed inside the foaming gun body 111. The discharge port 120 of the mixing chamber 110 is arranged on the side wall of the flow channel and is connected to the flow channel. The feeding system is used to input the foaming material 200. The outlet of the feeding system is connected to the feed port of the mixing chamber 110. A cleaning piston 130 is provided in the flow channel. The cleaning piston 130 changes the size of the discharge port 120 by moving, thereby changing the flow rate of the foaming material 200 and finally changing the landing position of the foaming material 200.

[0102] The drive system is a hydraulic system, and the piston rod of the hydraulic system is connected to the cleaning piston 130. The control system is a PLC control system, and the PLC control system is electrically connected to the precise feedback system, the adjustment system, and the hydraulic system, respectively. The adjustment system is electrically connected to the feeding system. The adjustment system is a frequency converter, and the feeding system is a feeding pump. In addition to changing the flow rate to change the landing point of the foaming material 200, the foaming equipment can also change the landing point of the foaming material 200 by changing the flow rate of the foaming material 200. The adjustment system controls the speed of the feeding pump according to the parameter requirements of converting the flow rate into a speed to achieve the adjustment of the landing point and flow rate of the foaming material 200 on the gun head. This situation is suitable for cavities with relatively short injection times.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

[0104] The above embodiments are intended to illustrate the present invention only and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that various combinations, modifications, or equivalent substitutions of the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and should be encompassed by the scope of the claims of the present invention.

Claims

1. A foaming method, characterized in that: The foaming method comprises the following steps: Keep the flow of foaming material constant; Maintaining a constant size of the discharge port of the mixing bin so that the foaming material remains at an initial landing position on the back panel of the box for a first predetermined period of time; Adjusting the size of the discharge port so that the middle landing point of the foaming material changes along a predetermined route; Maintaining a constant size of the discharge port so that the foaming material stops at the final landing point on the back plate for a second predetermined time; The adjusting of the size of the discharge port comprises: If the average thickness of the foaming layer is less than L, and the injection time is less than the milky white time of the foaming material, the cleaning piston is driven to move away from the muzzle of the foaming gun body to enlarge the discharge port; Alternatively, if the average thickness of the foaming layer is greater than L and the injection time is less than the milky white time of the foaming material, the cleaning piston is driven to move toward the muzzle of the foaming gun body to reduce the discharge port; Alternatively, if the injection time is longer than the milky time of the foaming material, the cleaning piston is driven to move first toward the muzzle of the foaming gun body and then away from the muzzle of the foaming gun body, so that the discharge port is first reduced and then increased.

2. The foaming method according to claim 1, characterized in that The pause time of each intermediate landing point of the foaming material is equal or partially equal.

3. The foaming method according to claim 1 or 2, characterized in that The initial landing point position and the final landing point position are the same position, or different positions on the same straight line.

4. The foaming method according to claim 1 or 2, characterized in that The box body comprises a refrigerator shell and a refrigerator liner arranged inside the refrigerator shell, and a cavity for accommodating the foaming material is formed between the refrigerator shell and the refrigerator liner.

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