Ice making unit manufacturing method

Abstract

To provide a method for manufacturing an ice making unit, capable of enhancing connection strength between an ice making plate and an evaporation pipe and improving product quality.SOLUTION: An evaporation pipe is formed into a flat shape that is wider on a side facing an ice making plate, and the evaporation pipe is plated with nickel. A nickel brazing material is applied to a joint surface of the ice making plate with the evaporation pipe. A pair of ice making plates is set on a jig so that they are facing each other with the evaporation pipe interposed therebetween. With the ice making plate and the evaporation pipe set in the jig, a gap between the evaporation pipe and the ice making plate and the parallelism of the pair of ice making plates are made appropriate. The jig in which the pair of ice making plates and the evaporation pipe are set is heated to a temperature suitable for the nickel brazing material, using a continuous vacuum furnace, and brazing is performed in the furnace in a state where the ice making plate and the evaporator pipe are not pressurized in a direction in which they overlap.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an ice making unit in which an evaporator tube and an ice making plate are arranged opposite each other. [Background technology]

[0002] A known ice-making machine that produces a large amount of ice blocks is a flow-down ice-making machine, which arranges a pair of ice-making plates facing each other across an evaporator pipe that constitutes a refrigeration system, sprays and supplies ice-making water onto the surface (ice-making surface) of each ice-making plate, which is cooled by a refrigerant circulated and supplied to the evaporator pipe, to form ice blocks, and then peels off the resulting ice blocks and drops them out (see, for example, Patent Document 1). Conventionally, the ice-making unit, which is composed of the pair of ice-making plates and evaporator pipe, is produced by overlapping the evaporator pipe with an ice-making plate to which a tape-like solder material is temporarily attached where it contacts the evaporator pipe, heating and cooling them while applying pressure in the overlapping direction, and soldering the evaporator pipe and ice-making plate together. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-257607 Summary of the Invention [Problem to be solved by the invention]

[0004] In the manufacturing method of the ice-making unit, which solders the ice-making plate and evaporator tube, the strength of the solder material itself is low. Furthermore, numerous voids (air bubbles) are generated due to the inability to evaporate gas generated during the melting of the solder material. Therefore, by increasing the amount of solder and enlarging the fillet, the contact area between the ice-making plate and the evaporator tube is increased, thereby improving the joint strength, durability, and corrosion resistance. However, due to the low thermal conductivity of the solder material, when de-icing, spraying water directly on the evaporator tube to heat the ice-making plate and promote ice detachment, the large contact area due to the solder increases the resistance to heat conduction, resulting in a long de-icing time.

[0005] In addition, in conventional manufacturing methods, the evaporation tubes are deformed by applying pressure to increase the contact area with the ice-making plate, but this pressure exerts a compressive load on the surface of the ice-making plate, causing the plate to deform, reducing its flatness and scratching it, resulting in a deterioration in quality. Furthermore, a low-quality ice-making unit with a scratched or poorly flat ice-making plate can affect the way ice blocks fall during de-icing, potentially causing problems such as ice blocks getting caught.

[0006] The present invention has been proposed in consideration of the above-mentioned problems inherent in the conventional technology, and aims to provide a method for manufacturing an ice-making unit that increases the bonding strength between the ice-making plate and the evaporator tube and improves product quality. [Means for solving the problem]

[0007] In order to overcome the above problems and achieve the intended purpose, the method for manufacturing an ice-making unit according to the invention of claim 1 comprises: A method for manufacturing an ice making unit in a flow-down ice making machine, the ice making unit comprising an ice making plate (12) and an evaporator tube (14), The ice-making plate (12) and the evaporation pipe (14) are arranged opposite each other, and the ice-making plate (12) and the evaporation pipe (14) are brazed together without applying pressure to the ice-making plate (12) and the evaporation pipe (14) in the overlapping direction. According to the invention of claim 1, the ice-making plate and the evaporator tube are joined by brazing, which increases the joint strength and improves the durability of the ice-making unit. Furthermore, because the brazing joint strength is high, the amount of brazing material used can be reduced compared to joining with solder, and the fillet in the ice-making unit can be made smaller, reducing the resistance to heat conduction during de-icing. Furthermore, because the ice-making plate and the evaporator tube are brazed without pressure, no compressive load is applied to the surface of the ice-making plate, preventing a decrease in flatness or scratches due to deformation. In other words, the product quality of the ice-making unit can be improved, and problems such as ice blocks getting caught during de-icing can be prevented.

[0008] The invention of claim 2 is characterized in that the evaporator tube (14) is formed in a flat shape with a wider side facing the ice-making plate (12), and is arranged to face the ice-making plate (12) and brazed thereto. According to the invention of claim 2, the evaporation pipe is formed in a flat shape with a wider surface facing the ice making plate, which increases the joining area between the ice making plate and the evaporation pipe, thereby further improving the joining strength. Moreover, since the evaporation pipe is formed in a flat shape in advance, the evaporation pipe can be formed in a uniform flat shape, which makes the joining degree between the ice making plate and the evaporation pipe uniform, thereby further improving quality.

[0009] The invention of claim 3 is characterized in that the ice making plate and the evaporator tube are brazed with a nickel brazing material. According to the invention of claim 3, the use of a nickel brazing filler metal can improve corrosion resistance. In addition, nickel brazing filler metal is less likely to generate gas during melting, resulting in fewer voids, and can further improve joining strength and durability.

[0010] The invention of claim 4 is characterized in that the evaporator tube (14) is disposed opposite to and brazed to the ice making plate (12) coated with a nickel brazing material. According to the invention of claim 4, the nickel brazing material is applied to the ice making plate before it is placed opposite the evaporator tube, so that an appropriate amount of nickel brazing material can be applied to the appropriate position on the ice making plate, and the degree of bonding between the ice making plate and the evaporator tube can be made uniform. In other words, a high-quality ice making unit can be manufactured without uneven cooling during ice making or uneven heating during de-icing.

[0011] The invention of claim 5 is characterized in that the nickel-plated evaporator tube (14) is disposed opposite the ice making plate (12) and brazed thereto. According to the invention of claim 5, a nickel coating is formed uniformly on the surface of the evaporator tube by plating, which makes it possible to uniformly bond the ice making plate and the evaporator tube, thereby producing a high-quality ice making unit that does not cause uneven cooling during ice making or uneven heating during de-icing.

[0012] The invention of claim 6 is characterized in that the ice-making plate (12) and the evaporation pipe (14) are brazed together in a state in which the ice-making plate (12) and the evaporation pipe (14) are set in a jig (16) so that an appropriate gap is formed between them. According to the invention of claim 6, brazing is performed with the ice making plate and evaporator tube set in a jig manufactured to ensure an appropriate gap between the evaporator tube and the ice making plate, thereby achieving a uniform degree of bonding between the ice making plate and the evaporator tube and improving product quality.

[0013] The invention of claim 7 is characterized in that the evaporator tube (14) and a pair of ice-making plates (12, 12) facing each other across the evaporator tube (14) are set in a jig (16) so that the pair of ice-making plates (12, 12) are appropriately parallel, and then the ice-making plates (12) and the evaporator tube (14) are brazed together. In the invention of claim 7, the brazing is performed while the evaporator tube and a pair of ice making plates are set in a jig so that the parallelism of the plates is appropriate, thereby resulting in a uniform degree of bonding between the ice making plates and the evaporator tube and improving the quality of the manufactured ice making unit.

[0014] According to an eighth aspect of the present invention, the ice making plate (12) and the evaporator tube (14) are brazed together using a vacuum furnace. According to the invention of claim 8, the ice making plate and evaporator tube are heated and brazed in their entirety, allowing for high-precision joining with minimal distortion, and enabling evaporator tubes with complex, meandering shapes to be properly joined to the ice making plate at multiple locations. Furthermore, no oxide film forms on the surfaces of the ice making plate or evaporator tube, resulting in a good-looking joint. Furthermore, since the ice making plate and evaporator tube can be joined without the use of flux, not only is post-processing to remove flux unnecessary, but environmental pollution and corrosion caused by residual flux are also eliminated, resulting in a good-looking ice making unit. Furthermore, vacuum furnace brazing prevents voids (air bubbles) from forming in the joint due to degassing, thereby increasing the joint strength.

[0015] The invention of claim 9 is characterized in that the ice making plate and the evaporator tube are brazed together using a reduction furnace in a reducing gas atmosphere. According to the invention of claim 9, the ice making plate and the evaporator tube are heated and brazed in their entirety, which allows for a highly accurate joint with little distortion and allows for the snaking, complex-shaped evaporator tube to be properly joined to the ice making plate at multiple locations. Furthermore, since no oxide film is formed on the surface of the ice making plate or the evaporator tube, the joint looks good. Furthermore, since the joint can be performed without using flux, not only is there no need for post-processing to remove the flux, but there is also no environmental pollution or corrosion problems caused by residual flux, and a good appearance can be achieved. [Effects of the Invention]

[0016] According to the method for manufacturing an ice-making unit of the present invention, the bonding strength between the ice-making plate and the evaporator tube is high, and a high-quality ice-making unit can be manufactured. [Brief explanation of the drawings]

[0017] [Figure 1] 4A to 4C are process diagrams of a method for manufacturing an ice-making unit according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing the ice making section of the flow-down type ice maker. [Figure 3] FIG. 2 is a schematic plan view showing the ice making section of the flow-down type ice maker. [Figure 4] 10 is a schematic plan view showing the ice making plate and evaporator tube set in the jig. FIG. [Figure 5] 10 is a schematic front view showing the ice making plate and evaporator tube set in the jig. FIG. [Figure 6] (a) is an explanatory diagram showing a fillet of solder material joining the ice making plate and the evaporator tube, and (b) is an explanatory diagram showing a fillet of brazing material joining the ice making plate and the evaporator tube. [Figure 7] 10A to 10C are process diagrams of a method for manufacturing an ice making unit according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Next, a method for manufacturing an ice-making unit according to the present invention will be described below by way of a preferred embodiment with reference to the accompanying drawings. [Example]

[0019] Before describing a manufacturing method for an ice-making unit according to an embodiment, the ice-making unit of a flow-down type ice maker manufactured by this manufacturing method will be described. As shown in Figures 2 and 3, ice-making unit 10 is composed of a pair of ice-making plates 12, 12 arranged facing each other at a distance in a vertical or nearly vertical position, and an evaporator pipe 14 that constitutes a refrigeration system and is sandwiched between the opposing surfaces (between the back surfaces) of ice-making plates 12, 12. In ice-making unit 10, a refrigerant is circulated through evaporator pipe 14 to forcibly cool ice-making plates 12, 12 during the ice-making process, and a hot gas (high-temperature refrigerant) is supplied to evaporator pipe 14 by switching a valve in the refrigeration system to heat ice-making plates 12, 12 during the de-icing process. In addition, an ice-making water supply means (neither shown) is provided at the top of the ice-making section 10 to supply ice-making water to the surface (ice-making surface) of each ice-making plate 12 during the ice-making process, and a de-icing water supply means (neither shown) to supply de-icing water between the opposing surfaces of the ice-making plates 12, 12 during the de-icing process.

[0020] As shown in Figures 2 and 3, each ice making plate 12 has multiple protrusions 12a extending vertically and spaced laterally at predetermined intervals, forming a flat, vertically extending ice making surface 12b between adjacent laterally adjacent protrusions 12a. Each protrusion 12a is convex on its front side, away from the other ice making plate 12, and concave on its back side, opening toward the other ice making plate 12, forming a roughly V-shape in plan view. The evaporator tube 14 is serpentine, with multiple straight pipe sections 14a and curved pipe sections 14b. The straight pipe sections 14a, extending horizontally and spaced apart vertically, are positioned between the ice making plates 12, and the curved pipe sections 14b are positioned on the sides of the ice making plates 12, so that the straight pipe sections 14a are sandwiched between the back surfaces of the ice making surfaces 12b.

[0021] Here, methods for joining two metals include "soldering," which uses a "solder material" made of an alloy primarily composed of tin and lead as the joining material, and "brazing," which uses a "filler material" made of various alloys with a lower melting point than the base metal as the joining material. Academically, "soldering" and "brazing" are both types of welding, and "soldering" is generally referred to as using a joining material (soft solder material) with a melting point of 450°C or less when heated, while "brazing" is generally referred to as using a joining material (hard solder material) with a melting point of 450°C or more. In the present invention, hard solder material is used to braze ice-making plate 12 and evaporator tube 14.

[0022] In the manufacturing method of the ice-making unit of this embodiment, the ice-making plate 12 and the evaporator tube 14 are joined together using a nickel brazing material as a hard brazing material. As shown in FIG. 1 , before brazing the ice-making plate 12 to the evaporator tube 14, the evaporator tube 14 is first formed into a flat shape (see FIG. 2 ) using a press mold or the like, with a wider side facing the ice-making plate 12, so as to increase the contact area with the ice-making plate 12. The evaporator tube 14 is then nickel-plated to form a coating of nickel as a brazing material with a predetermined thickness on its surface. The ice-making plate 12 is then pre-coated with a nickel brazing material to a predetermined thickness on its joining surface (back surface) with the evaporator tube 14. The nickel-plated evaporator tube 14 and the ice-making plates 12, 12 coated with the nickel brazing material are then set in a jig 16 shown in FIGS. 4 and 5 so that the pair of ice-making plates 12, 12 face each other with the evaporator tube 14 sandwiched between them. Jig 16 is manufactured so that the gap between evaporator tube 14 and ice-making plates 12, 12 and the parallelism of the pair of ice-making plates 12, 12 (flat ice-making surfaces 12b, 12b) are appropriate, and by setting ice-making plates 12, 12 and evaporator tube 14 in jig 16, the positional relationship (gap and parallelism) between ice-making plates 12, 12 and evaporator tube 14 is maintained in an appropriate state. Furthermore, when ice-making plates 12, 12 and evaporator tube 14 are set in jig 16, their relative positional relationship is maintained appropriately without pressure being applied in the overlapping direction.

[0023] 1, the jig 16 holding the pair of ice-making plates 12, 12 and the evaporation tube 14 is heated in a continuous vacuum furnace to a temperature suitable for the nickel brazing material, and brazing is performed in the furnace without applying pressure to the ice-making plates 12, 12 and the evaporation tube 14 in the overlapping direction. A continuous vacuum furnace is provided with a conveying means inside the furnace, and a preheating section, a heating section, and a cooling section are set in this order from the upstream side in the conveying direction. The ice-making plates 12, 12 held in the jig 16 are brazed to the evaporation tube 14 by conveying the jig 16 with the conveying means.

[0024] [Operation of the Example] Next, the operation of the method for manufacturing the ice-making unit according to the embodiment will be described.

[0025] According to the manufacturing method of the embodiment, ice-making plates 12 and evaporator tubes 14 are joined by brazing, which increases the joint strength and improves the durability of ice-making unit 10 compared to soldering. Furthermore, because the joint strength can be increased without increasing the contact area of ​​the fillet, the amount of brazing material used can be reduced compared to joining with solder, and the fillet can be made smaller, reducing the resistance to heat conduction during deicing. Furthermore, because ice-making plates 12 and evaporator tubes 14 are brazed without pressure, no compressive load is applied to the surface of ice-making plate 12, preventing deformation that could reduce the flatness of ice-making plate 12 or damage it. In other words, a high-quality ice-making unit 10 can be manufactured that does not cause problems such as ice blocks getting caught during deicing.

[0026] In the manufacturing method of the embodiment, the evaporator tube 14 is formed in a flat shape with a wider surface facing the ice-making plate 12, thereby increasing the joint area between the ice-making plate 12 and the evaporator tube 14 and further improving the joint strength. Moreover, because the evaporator tube 14 is formed in a flat shape in advance, the evaporator tube 14 can be formed into a uniform flat shape using a press mold or the like, resulting in a uniform degree of joint between the ice-making plate 12 and the evaporator tube 14 and further improving quality. That is, in the conventional method of deforming the evaporator tube 14 by applying pressure during soldering to increase the contact area with the ice-making plate 12, if the tape-shaped solder material is not uniformly temporarily attached to the ice-making plate 12, the evaporator tube 14 will deform non-uniformly, resulting in an uneven degree of joint between the ice-making plate 12 and the evaporator tube 14. However, this situation does not occur in the manufacturing method of the embodiment.

[0027] In the manufacturing method of the embodiment, nickel brazing filler metal is used as the brazing filler metal, thereby improving corrosion resistance. Furthermore, nickel brazing filler metal is less likely to generate gas during melting, resulting in fewer voids and improved joint strength and durability. Furthermore, nickel brazing filler metal is applied to the joint surface of ice-making plate 12 before it is set in jig 16. This allows for the application of an appropriate amount of nickel brazing filler metal to the appropriate position on ice-making plate 12, thereby ensuring a uniform joint between ice-making plate 12 and evaporator tube 14. Furthermore, a uniform nickel coating is formed on the surface of evaporator tube 14 by plating, ensuring a uniform joint between ice-making plate 12 and evaporator tube 14. This means that a high-quality ice-making unit 10 can be manufactured without uneven cooling during ice making or uneven heating during de-icing.

[0028] In the manufacturing method of the embodiment, the ice-making plates 12, 12 and the evaporator tube 14 are set in a jig 16 manufactured so that the gap between the ice-making plates 12, 12 and the evaporator tube 14 and the parallelism of the pair of ice-making plates 12, 12 are appropriate, and brazing is then performed in that state.This results in a uniform degree of bonding between the ice-making plates 12 and the evaporator tube 14, further improving the quality of the manufactured ice-making unit 10.

[0029] In the manufacturing method of the embodiment, the ice-making plates 12, 12 and the evaporator tube 14 are brazed in a continuous vacuum furnace. This allows for high-precision bonding with minimal distortion by heating the entire ice-making plates 12, 12 and the evaporator tube 14. Furthermore, since no oxide film forms on the surfaces of the ice-making plates 12 or the evaporator tube 14, the bond looks attractive. Furnace brazing using a continuous vacuum furnace allows for bonding of the ice-making plates 12 and the evaporator tube 14 without the use of flux, eliminating the need for post-processing to remove flux and the risk of environmental pollution or corrosion due to residual flux. A good-looking ice-making unit 10 can be manufactured. Furthermore, vacuum furnace brazing prevents voids (air bubbles) from forming in the bonded area due to degassing, thereby increasing bond strength.

[0030] Here, when soldering the ice-making plate 12 and the evaporator tube 14 together using solder, the amount of solder required to obtain the specified joint strength and durability is as shown in Figure 6(a), and the fillets of the solder formed at the upper and lower corners formed by the ice-making plate 12 on the side of the evaporator tube 14 facing the ice-making plate 12 have a fillet shape R of approximately 1 mm.As a result, when the vertical dimension at the longest part of the evaporator tube 14 is approximately 15 mm, the contact length L1 between the evaporator tube 14 and the ice-making plate 12, including the fillets, is approximately 12.5 mm. In contrast, when using a brazing material to braze an ice-making plate 12 to an evaporator tube 14 having a vertical dimension of approximately 15 mm at its longest point, it has been verified that if the R of the fillet shape of the brazing material formed at the corner is approximately 0.5 mm and the contact length L2 between the evaporator tube 14 and the ice-making plate 12, including the fillet, is approximately 10.6 mm, joint strength and durability equivalent to those achieved when using solder material can be obtained. That is, it is possible to reduce the amount of brazing material used when manufacturing ice-making unit 10 with joint strength and durability equivalent to that achieved with soldering. This reduces the contact area between ice-making plate 12 and evaporator tube 14 caused by the brazing material, and when water is sprayed directly onto evaporator tube 14 to heat ice-making plate 12 and promote the separation of ice blocks during de-icing in ice-making unit 10, the resistance to heat conduction caused by the brazing material is reduced, making it possible to quickly separate the ice blocks.

[0031] (Regarding another embodiment) In the above embodiment, the ice making plates 12 and the evaporation tubes 14 are brazed using a continuous vacuum furnace, but in another embodiment, the only difference is that the ice making plates 12 and the evaporation tubes 14 are brazed using a continuous reduction furnace with a reducing gas atmosphere created by hydrogen gas, which is a reducing gas. Like the above continuous vacuum furnace, the continuous reduction furnace is provided with a conveying means within the furnace, and a preheating section, a heating section, and a cooling section are set in this order from the upstream side in the conveying direction. By conveying a jig 16 with the conveying means, the ice making plates 12, 12 and the evaporation tubes 14 set on the jig 16 are brazed without being pressurized in the overlapping direction.

[0032] In another embodiment of the method for manufacturing an ice-making unit, the ice-making plates 12, 12 and the evaporator tube 14 are brazed together using a continuous reduction furnace. This allows for high-precision joining with minimal distortion by heating the entire ice-making plates 12, 12 and the evaporator tube 14. Furthermore, the snaking, complex-shaped evaporator tube 14 can be properly joined to the ice-making plates 12, 12 at multiple locations. Furthermore, because no oxide film forms on the surfaces of the ice-making plates 12 or the evaporator tube 14, the joining can be made with a good appearance. Furthermore, furnace brazing using a continuous reduction furnace allows for joining the ice-making plates 12 and the evaporator tube 14 without the use of flux. This eliminates the need for post-processing to remove flux, and also eliminates the environmental pollution and corrosion problems caused by residual flux, resulting in the manufacture of an ice-making unit 10 with a good appearance.

[0033] [Example of change] The present application is not limited to the methods of the above-described examples and other examples, and other methods may be adopted as appropriate. Furthermore, the methods described in the examples and other examples may be implemented in various ways within the scope of the present invention, without being limited to the following modifications. 1. In the examples, nickel brazing filler metal is used as the brazing filler metal, but brazing filler metals of various other materials that do not pose food hygiene problems can also be used. 2. In the examples, an ice-making unit is manufactured in a configuration in which a pair of ice-making plates are arranged opposite each other with an evaporator tube sandwiched therebetween, but an ice-making unit in a configuration in which an evaporator tube and one ice-making plate are arranged opposite each other may also be manufactured. 3. In the examples, a continuous vacuum furnace or reduction furnace is used, but a batch vacuum furnace or reduction furnace may also be used to braze the ice making plate and the evaporator tube. [Explanation of symbols]

[0034] 12 ice making plate, 14 evaporator tube, 16 jig

Claims

1. A method for manufacturing an ice making unit consisting of an ice making plate and an evaporator tube in a flow-down type ice maker, The ice-making plate and the evaporation tube are arranged opposite to each other, and the ice-making plate and the evaporation tube are brazed together without applying pressure to the ice-making plate and the evaporation tube in the overlapping direction. A method for manufacturing an ice-making unit.

2. 2. The method for manufacturing an ice-making unit according to claim 1, wherein the evaporator tube is formed in a flat shape so that the side facing the ice-making plate is wider, and the evaporator tube is disposed opposite the ice-making plate and brazed.

3. 3. The method for manufacturing an ice-making unit according to claim 1, wherein the ice-making plate and the evaporator tube are brazed with a nickel brazing material.

4. 4. The method for manufacturing an ice-making unit according to claim 1, wherein the evaporator tube is disposed opposite the ice-making plate coated with a nickel brazing material and brazed to the ice-making plate.

5. 5. The method for manufacturing an ice-making unit according to claim 1, wherein the nickel-plated evaporator tube is disposed opposite the ice-making plate and brazed to the ice-making plate.

6. A method for manufacturing an ice making unit described in any one of claims 1 to 5, wherein the ice making plate and the evaporator tube are brazed together while being set in a jig so that an appropriate gap is maintained between them.

7. A method for manufacturing an ice-making unit described in any one of claims 1 to 6, wherein the evaporator tube and a pair of ice-making plates facing each other across the evaporator tube are set in a jig so that the parallelism of the pair of ice-making plates is appropriate, and then the ice-making plates and the evaporator tube are brazed together.

8. The method for manufacturing an ice-making unit according to any one of claims 1 to 7, wherein the ice-making plate and the evaporator tube are brazed using a vacuum furnace.

9. The method for manufacturing an ice-making unit according to any one of claims 1 to 7, wherein the ice-making plate and the evaporator tube are brazed together using a reducing furnace in a reducing gas atmosphere.

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