A heat exchanger, a cooling container and system comprising such, and a method for manufacturing a heat exchanger and a cooling container

Abstract

The present disclosure relates to a heat exchanger (1a, 1b) for a cooling container, such as a tank for milk cooling, the heat exchanger (1a, 1b) comprising: a pair of plate materials (2a, 2b), an inlet (12) for a coolant, and an outlet (13) for the coolant; wherein a peripheral portion of at least one of the plate materials is joined to the other plate material by a seal (14) such to form a sealed coolant passage space (11) between the plate materials (2a, 2b), and wherein the pair of plate materials (2a, 2b) are welded together by a weld pattern (30), wherein the weld pattern comprises a plurality of welded spots (31), wherein the weld pattern comprises at least one welded baffle line (32) for directing a flow of coolant from the inlet (12) to the outlet (13) when in use, wherein the welded baffle line (32) comprises a main portion (321) extending in a first direction, and an end portion (322) extending in a second direction being different from the first direction. The present disclosure further relates to a heat exchanger assembly, a cooling container, a system comprising a cooling container and a coolant, a method of producing a heat exchanger and a cooling container, and a method of cooling milk.

Description

Technical field

[0001] The present disclosure relates to a heat exchanger, in particular for a cooling container, such as a tank for milk cooling. Further is also a method for manufacturing a heat exchanger disclosed.

[0002] The disclosure also relates to a heat exchanger assembly, a cooling container comprising a heat exchanger or a heat exchanger assembly, to a system comprising a cooling container, to a method for manufacturing a cooling container, and to a method for cooling milk by a cooling container.Background

[0003] In dairy production, hygiene and efficient utilization of milk already on the farm are important, to fulfill requirements for food production. At farms, large tanks or silos are used for storing milk produced before the milk is transported to dairies. Different environments and different amount of milk in a tank or silo require different efficiency of the cooling equipment. The milk is preferably to be kept at a constant temperature around 3°C, and not to higher or lower than this.

[0004] In cooling circuits of such tanks and silos, it has commonly been used coolants that are hazardous and not environmentally friendly. These coolants are to be phased out of the market, and replaced with more environmentally friendly coolants. However, some of these coolants, for example CO 2 , requires a much higher pressure, which put needs on the construction of the cooling circuits and heat exchangers.

[0005] Heat exchangers are commonly placed in the bottom of a tank or silo for cooling the milk. The milk is agitated in the tank or silo to get a good cooling of the milk. In a silo, circular heat exchangers are often used, to be able to cover the whole bottom surface of the silo. However, these circular heat exchangers are more complicated to manufacture than a rectangular heat exchanger.

[0006] Further, in cooling systems, lubrication of the compressor is important for the service life of the compressor and for high performance of the cooling system. However, oil may be carried with the coolant to other parts of the cooling system. There is a problem of oil being lost over time and not being efficiently returned to the compressor. Without sufficient oil return, the compressor may break. Accumulation of oil in any part of the cooling system may result in decreased cooling efficiency. It is known to use an oil separator to reduce the risk of oil accumulation. However, an oil separator may not fully eliminate the risk of oil accumulation in the system. Thus, efficient oil return is desirable, both for the service life of the compressor and for a secure and reliable cooling system.

[0007] It is therefore needed a new and improved heat exchanger and cooling system to alleviate at least some of above mentioned problems.Summary

[0008] It is an object of the present disclosure to provide an improved solution that alleviates at least some of the above mentioned drawbacks with present solutions. In particular, there is an object to provide an improved heat exchanger, heat exchanger assembly, cooling container and / or cooling system having an improved cooling efficiency and / or improved oil return. There is a further object to provide an improved method for manufacturing a heat exchanger and / or cooling container.

[0009] The invention is defined by the appended independent claims, with embodiments being set forth in the appended dependent claims, in the following description and in the drawings.

[0010] According to a first aspect, there is provided a heat exchanger for a cooling container, such as a tank for milk cooling, the heat exchanger comprising a pair of plate materials, an inlet for a coolant, and an outlet for the coolant. A peripheral portion of at least one of the plate materials is joined to the other plate material by a seal such to form a sealed coolant passage space between the plate materials. The pair of plate materials are welded together by a weld pattern, wherein the weld pattern comprises a plurality of welded spots. The weld pattern comprises at least one welded baffle line for directing a flow of coolant from the inlet to the outlet when in use, wherein the welded baffle line comprises a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0011] The heat exchanger is suitable for use as an evaporator. Thus, the heat exchanger may be an evaporator for a cooling container for cooling of a liquid, such as for example milk. The heat exchanger is particularly suitable for use as an evaporator for large cooling containers, such as milk tanks or milk silos.

[0012] The heat exchanger plate may be formed as a pillow plate, preferably a single-embossed pillow plate. Thus, as seen after an inflation-process used to form a "pillow-shaped" surface of the heat exchanger, one side of the plates welded together may be flat. The other side may be deformed. The flat side may form a product face, i.e. a surface adapted to be in contact with a product, such a milk. Thus, the flat side may be adapted to form an inner surface of a cooling container.

[0013] The pair of plate materials may be provided in form of two metal plates. The pair of plate materials may be made of any suitable metal or metal alloy, preferably stainless steel. One of the pair of plate materials may present a first thickness. The other one of pair of plate materials may present a second thickness. The first and second thicknesses may vary. Thus, the pair of plate materials may have a varying thickness in relation to one another. The size and shape of the two metal plates may vary.

[0014] Alternatively, the size and shape of the two metal plates may be essentially the same.

[0015] The coolant passage space formed between the plate materials may be configured to allow a flow of coolant through the space, from the inlet to the outlet of the heat exchanger, when in use.

[0016] The heat exchanger may have an at least partly curved periphery.

[0017] Said seal may be provided in form of a welded seal. Thus, the pair of plate materials may be welded together by a welded seal extending along an edge portion of at least one of the plates. The seal may be formed by seam welding, such as laser seam welding.

[0018] The welded spots may form a spot pattern. The spots may be formed by spot welding, such as laser spot welding.

[0019] The seal can be seen to extend such to encompass said weld pattern. Thus, the seal can be seen as an outermost limit of said weld pattern.

[0020] The seal can comprise at least one curved portion.

[0021] The at least one welded baffle line may be provided for directing a flow of coolant in a meandering path, from the inlet to the outlet.

[0022] The heat exchanger may comprise a plurality of welded baffle lines. A space between two adjacent welded baffle lines may be seen to form a channel. For example, a space between a first welded baffle line and an adjacent second welded baffle line can be seen to form a first channel for passing a flow of coolant in a first direction. The first channel can open up into a turning zone. The turning zone can be seen as a space wherein the flow is forced to change direction. A space between the second welded baffle line and an adjacent third welded baffle line can be seen to form a second channel for passing a flow of coolant in a second direction, opposite to the first direction of the first channel. The second channel may open up into another turning zone.

[0023] The coolant may be a cooling medium or refrigerant in liquid or gas phase configured to be transported between the pair of plates. The coolant may transform between liquid and gas phase while heat-exchanging in the heat exchanger, or the coolant will be in the same phase, liquid or gas, while heat-exchanging in the heat exchanger.

[0024] The heat exchanger according to the above may preferably be used with a coolant in form of CO2. However, the heat exchanger may be used with any suitable coolant, such as for example a natural or a synthetic refrigerant.

[0025] When in use, a lubricant, such as an oil may be mixed with the coolant and flow with the coolant of the system. The oil may be insoluble with the coolant. Alternatively, the oil may be at least partly soluble with the coolant. The coolant may be at least partly soluble with the oil. The oil may for example be a polyol ester (POE) oil or a polyalkylene glycol (PAG) oil.

[0026] The heat exchanger according to the above allows for an improved cooling efficiency. Further, the heat exchanger according to the above reduces the risk of oil clogging or oil accumulation in the heat exchanger and allows for an improved oil return.

[0027] Said end portion of the welded baffle line may be located in a turning zone of the heat exchanger. According to one example, all turning zones may comprise an end portion of a welded baffle line, said end portion extending in a second direction being different from the first direction of a main portion of the welded baffle line.

[0028] Said end portion of the welded baffle line may be located between the inlet and the outlet, as seen along a flow path for the coolant. The flow path can be determined by the at least one welded baffle line for directing a flow of coolant from the inlet to the outlet. Thus, when in use, the coolant may pass said end portion when the coolant flows from the inlet towards the outlet.

[0029] The weld pattern may comprise two welded baffle lines for directing a flow of coolant from the inlet to the outlet when in use, wherein the two welded baffle lines each comprises a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0030] The weld pattern may comprise three, four, or five welded baffle lines for directing a flow of coolant from the inlet to the outlet when in use, wherein the three, four, or five welded baffle lines each comprises a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0031] The weld pattern may comprise a first welded baffle line and an adjacent second welded baffle line, wherein the first welded baffle line and the second welded baffle line form a channel for passing a flow of coolant between a first turning zone and a second turning zone, wherein each one of the first and second welded baffle lines comprises a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0032] The weld pattern may comprise a plurality of welded baffle lines, wherein at least two, at least three, at least four, or at least five of said plurality of welded baffle lines each comprises a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0033] The weld pattern may comprises a plurality of welded baffle lines for directing a flow of coolant from the inlet to the outlet, wherein at least 40 %, preferably at least 50 %, at least 60 % or at least 75 %, of the plurality of welded baffle lines each comprises a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0034] Thus, according to one example, a majority of the plurality of welded baffle lines may comprise a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction. By "majority" is meant more than 50 % of the total amount of welded baffle lines that are provided for directing a flow of coolant from the inlet to the outlet when in use. As one example, all of the welded baffle lines that are provided for directing a flow of coolant from the inlet to the outlet may each comprise a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0035] A first angle between the main portion and the end portion may be 80-160°, preferably 90-150° or 110-140°.

[0036] The main portion may extend as a first straight line.

[0037] The end portion may extend as a second straight line or as a curved line.

[0038] Said end portion may be connected to said seal.

[0039] Thus, a first end of said end portion is connected to the main portion of the welded baffle line. A second end of said end portion may be connected to the seal.

[0040] A second angle between the end portion and a tangent that tangents a connection point at which the end portion and seal connects, may be 70-120°, preferably 75-110° or 90-100°.

[0041] The end portion may intersect said seal.

[0042] Thus, the end portion may intersect and extend pass said seal. Thus, a second end of said end portion may be located closer to an outermost edge of said peripheral portion of at least one of the plate materials, than said seal.

[0043] Thereby a heat exchanger with improved quality and / or improved strength can be provided.

[0044] The weld pattern may comprise at least two welded baffle lines, wherein a distance between the main portions of two adjacent welded baffle lines may be 140-220 mm, or 150-215 mm, preferably 170-210 mm or 180-200 mm.

[0045] The plurality of welded spots may form a continuous diamond pattern having a first distance between the spots in a first direction and a second distance in second direction, wherein the first and the second directions may be perpendicular to each other. The first distance may be 15-35 mm, preferably 20-30 mm, and the second distance may be 30-60 mm, preferably 40-55 mm.

[0046] At least one of the pair of plate materials may have a zig-zag shaped edge portion.

[0047] The zig-zag shape may be provided by a zig-zag pattern. The zig-zag pattern may be provided along at least a portion of the periphery of the plate material, preferably along more than 50 % of the periphery, more preferably along more than 75 % or along more than 90 % of the periphery of the plate material. The zig-zag pattern may be substantially regular along said at least a portion of the periphery of the plate material. The zig-zag pattern may comprise a plurality of triangles having a height of 3-15 mm, preferably 5-13 mm or 7-11 mm. Thus, a radial extent of said zig-zag pattern may be 3-15 mm, preferably 5-13 mm or 7-11 mm. The zig-zag pattern may have an internal angle of 30-120°, preferably 35-90° or 40-60°.

[0048] The zig-zag shape may be provided in form of a cut zig-zag pattern provided along at least a portion of the periphery of the plate material. Thus, the zig-zag shape may be provided by a cutting operation before the pair of plate materials are welded together.

[0049] The zig-zag shape may enable joining the plate materials together. In particular, the zig-zag shape prevents undesirable displacement of the plate materials relative to one another during the step of providing the seal. The zig-zag shape can enable welding the plate materials together. Furthermore, it can release stresses of the plate materials and prevent breakage of the seal, thus allowing for a heat exchanger with improved quality and / or strength. By having a zig-zag shaped edge portion, the plate materials may be allowed to shrink without interfering with the design of the design of the heat exchanger, and the risk of warping is decreased.

[0050] The weld pattern may comprise at least two welded baffle lines, wherein at least a portion of the respective main portions of the at least two welded baffle lines are parallel to one another.

[0051] The heat exchanger may have a substantially circular, semicircular or crescent shape.

[0052] The heat exchanger may have a diameter of 1.5-5 m, preferably 2-3.5 m.

[0053] The heat exchanger may have a surface area of 2-8 m 2< , preferably 3-6 m 2< .

[0054] A first side of the heat exchanger may present a substantially flat surface, and an opposite second side of the heat exchanger may present a substantially flat surface.

[0055] Thus, the heat exchanger may be uninflated i.e. the pair of plate materials may be substantially flat and not deformed.

[0056] Alternatively, a first side of the heat exchanger may present a substantially flat surface, and an opposite second side of the heat exchanger may present a deformed surface.

[0057] Thus, the heat exchanger may be inflated. I.e. one of the pair of plate materials may be substantially flat and the other one may be deformed.

[0058] According to a second aspect, there is provided a heat exchanger for a cooling container, such as a tank for milk cooling, the heat exchanger comprises a pair of plate materials, an inlet for a coolant, and an outlet for the coolant. A peripheral portion of at least one of the plate materials is joined to the other plate material by a seal such to form a sealed coolant passage space between the plate materials. The pair of plate materials are welded together by a weld pattern, wherein the weld pattern comprises a plurality of welded spots. The weld pattern comprises two welded baffle lines for directing a flow of coolant from the inlet to the outlet when in use, wherein a distance between the two welded baffle lines is 140-220 mm or 150-215 mm, preferably 170-210 mm or 180-200 mm.

[0059] The heat exchanger is suitable for use as an evaporator. Thus, the heat exchanger may be an evaporator for a cooling container for cooling of a liquid, such as for example milk. The heat exchanger is particularly suitable for use as an evaporator for large cooling containers, such as milk tanks or milk silos. Unless stated otherwise, the heat exchanger may be designed and / or configured essentially the same as the heat exchanger as described in relation to the first aspect.

[0060] The two welded baffle lines may be parallel to one another.

[0061] Each of the two welded baffle lines may comprise a main portion extending in a first direction. Thus, a distance between the main portions of the two welded baffles lines may be 140-220 mm or 150-215 mm, preferably 170-210 mm or 180-200 mm. Further, each of the two welded baffle lines may comprise an end portion extending in a second direction. The second direction may be the same or different from the first direction.

[0062] The heat exchanger according to the second aspect may preferably be used with a coolant in form of CO 2 . However, the heat exchanger may be used with any suitable coolant, such as for example a natural or a synthetic refrigerant.

[0063] When in use, a lubricant, such as an oil may be mixed with the coolant and flow with the coolant of the system. The oil may be insoluble with the coolant. Alternatively, the oil may be at least partly soluble with the coolant. The coolant may be at least partly soluble with the oil. The oil may for example be a polyol ester (POE) oil or a polyalkylene glycol (PAG) oil.

[0064] The heat exchanger according to the second aspect allows for an improved cooling efficiency.

[0065] The plurality of welded spots may form a continuous diamond pattern having a first distance between the spots in a first direction and a second distance in second direction, wherein the first and the second directions are perpendicular to each other. The first distance may be 15-35 mm, preferably 20-30 mm, and the second distance may be 30-60 mm, preferably 40-55 mm.

[0066] A first side of the heat exchanger may present a substantially flat surface, and an opposite second side of the heat exchanger may present a substantially flat surface.

[0067] Thus, the heat exchanger may be uninflated, i.e. the pair of plate materials may be substantially flat and not deformed.

[0068] Alternatively, a first side of the heat exchanger may present a substantially flat surface, and an opposite second side of the heat exchanger may present a deformed surface.

[0069] Thus, the heat exchanger may be inflated. I.e. one of the pair of plate materials may be substantially flat and the other one may be deformed.

[0070] According to a third aspect, there is provided a heat exchanger assembly comprising two heat exchangers as disclosed above, wherein the two heat exchangers are welded together.

[0071] The two heat exchangers may be welded together along a center line.

[0072] In the case of the heat exchangers having a substantially semicircular shape, the two heat exchangers may be welded together to form a substantially circular shape. The pair of plate materials may be bent. For example, the heat exchanger assembly may be formed so as to have a conical shape. The conical shape may be centered, or the conical shape may be shifted so that the mantle area is not uniformly shaped.

[0073] According to a fourth aspect, there is provided a cooling container comprising a heat exchanger as disclosed above or a heat exchanger assembly as disclosed above.

[0074] The cooling container may be a tank for cooling of a liquid, such as milk.

[0075] The cooling container may have an inner container space having a product volume of 1500-70 000 liter.

[0076] The cooling container may be a vertical cooling tank, such as a silo. For example, the cooling container may have a height of 2-10 meters. A diameter of the cooling container may be 1-5 meters, preferably 1.5-4 or 2-3.5 meters.

[0077] Alternatively, the cooling container may be a horizontal tank. For example, the cooling container may have a length of 2-10 meters. A height of the horizontal tank may for example be 1.5-3.5 meters. A width of the horizontal tank may for example be 1-3 meters.

[0078] The cooling container may comprise an agitator arranged inside the container for stirring of a liquid, when the liquid is placed in the container.

[0079] The heat exchanger or heat exchanger assembly may be arranged at a bottom portion of the cooling container.

[0080] The heat exchanger or heat exchanger assembly may present a surface forming an inner surface of the cooling container.

[0081] For example, the heat exchanger or heat exchanger assembly may present a surface forming an inner bottom surface of the cooling container. The surface of the heat exchanger or heat exchanger assembly forming the inner surface of the cooling container may be substantially flat.

[0082] According to a fifth aspect, there is provided a system comprising a cooling container as disclosed above, and a coolant.

[0083] The coolant may be anyone chosen from a group of CO 2 , propane, ammonium or a HFC refrigerant.

[0084] The heat exchanger may be used with any suitable coolant, such as for example a natural or a synthetic refrigerant.

[0085] A lubricant, such as an oil may be mixed with the coolant. The oil may be insoluble with the coolant. Alternatively, the oil may be at least partly soluble with the coolant. The coolant may be at least partly soluble with the oil. The oil may for example be a polyol ester (POE) oil or a polyalkylene glycol (PAG) oil.

[0086] The system may be an inverter-driven system.

[0087] The system may also be referred to as a frequency-driven system. Thus, the system may be configured such to control and adjust a flow rate of the coolant in the system.

[0088] The system may further comprise a controller, and a compressor, wherein the controller is configured to control the compressor.

[0089] The controller may control the compressor so that the compressor causes a flow of the coolant through the heat exchanger. The controller may control the flow so that the flow of the coolant may be varied in speed.

[0090] The compressor may be a variable speed compressor.

[0091] The variable speed compressor may also be referred to as an inverter compressor or inverter-driven compressor.

[0092] According to a sixth aspect, there is provided a method for manufacturing a heat exchanger comprising providing two plate materials, joining a peripheral portion of at least one of the plate materials to the other plate material by a seal, and welding the two plate materials together by a weld pattern, including: welding a plurality of spots, and welding at least one baffle line, wherein the at least one baffle line is welded such to comprise a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0093] The method may be used to manufacture a heat exchanger as described above.

[0094] The plate materials can be seen to be joined together so as to form a body of the heat exchanger.

[0095] The seal may be provided such to form a sealed coolant passage space between the plate materials.

[0096] The seal may be provided by welding. Thus, said seal may be provided in form of a welded seal. Thus, the pair of plate materials may be welded together by a welded seal extending along an edge portion of at least one of the plates. The seal may be formed by seam welding, such as laser seam welding. The seal may comprise at least one curved portion.

[0097] The weld pattern may be provided by laser welding.

[0098] The welded spots may form a spot pattern. The spots may be formed by spot welding, such as laser spot welding.

[0099] The at least one baffle line may be provided by laser welding.

[0100] The method may comprise aligning the plate materials so that a surface of each plate material is facing each other before the joining the plate materials.

[0101] The step of joining a peripheral portion of at least one of the plate materials to the other plate material by a seal, and the step of welding the two plate materials together by a weld pattern may be performed separately or simultaneously. As one example, the step of welding the two plate materials together by a weld pattern may be performed before the seal is provided. Alternatively, the seal may be provided before the weld pattern.

[0102] As one example, welding the plurality of spots may be performed before welding the at least one baffle line, which may be performed before joining the peripheral portion of the at least one of the plate materials to the other plate material by a seal. Alternatively, welding the plurality of spots may be performed before joining the peripheral portion of the at least one of the plate materials to the other plate material by a seal, which may be performed before welding the at least one baffle line. Alternatively, two or more of welding the plurality of spots, joining a peripheral portion of the at least one of the plate materials, and welding the at least one baffle line may be performed simultaneously.

[0103] The method may further comprise cutting at least one edge portion of one of the two plate materials into a zig-zag shape.

[0104] The cutting may be performed before the joining of the two plate materials. Thus, said joining may comprise joining a peripheral portion of the plate material comprising the edge portion that has been cut into a zig-zag shape, to the other plate material by the seal.

[0105] At least one of the two plate materials may have at least one edge being curved. The curved edge may be cut into the zig-zag shape in said cutting step.

[0106] According to a seventh aspect, there is provided a method for manufacturing a cooling container, comprising providing a heat exchanger obtained by the method as disclosed above, or a heat exchanger as disclosed above, forming the heat exchanger into a desired shape, and inflating the heat exchanger.

[0107] The method may be used to form a cooling container as described above.

[0108] The desired shape may be for example be conical or cylindrical.

[0109] The method may comprise joining the heat exchanger to a cooling container portion for forming the cooling container. For example, the method may comprise joining the heat exchanger to a container wall portion. The heat exchanger and container wall portion may define an inner container space for the product, i.e. an inner product space. The container wall portion may have a substantially cylindrical form. The container wall portion may form a main body of the cooling container. The joining may be performed by welding. Joining the heat exchanger to another cooling container portion may be performed before the inflation of the heat exchanger. Joining the heat exchanger to another cooling container portion may be performed after the heat exchanger has been formed into the desired shape. The container wall portion may form a support structure for the heat exchanger when being inflated. The support structure enables inflation of the heat exchanger, such to form the pillow structure of the heat exchanger, while also ensuring that the heat exchanger maintain the desired shape. Alternatively, a separate support structure, different from the container wall portion, may be provided. The support structure may have essentially the same shape as said desired shape of the heat exchanger. Thus, the heat exchanger may be placed within the support structure before being inflated.

[0110] Further, the step of forming the heat exchanger may comprise joining the heat exchanger to another heat exchanger by welding, such to form a heat exchanger assembly.

[0111] The step of forming the heat exchanger may comprise forming the heat exchanger or heat exchanger assembly into a conical-shaped end portion of the cooling container.

[0112] Thus, the heat exchanger or heat exchanger assembly may form a bottom portion of the product space of the cooling container.

[0113] The forming may comprise bending the heat exchanger or heat exchanger assembly, i.e. the pair of plate materials that are welded together may be processed, such as in a bending process, into the desired shape.

[0114] Thus, the heat exchanger may be formed into a cooling container or a portion of a cooling container, such as a bottom portion and / or a wall portion of the cooling container.

[0115] The method may further comprise joining the cooling container with a jacket. Thus, the cooling container may form an inner part, such as an inner cooling container, of a cooling tank assembly or cooling silo assembly. Thus the assembly may be seen to comprise an inner cooling container for holding the product, and an outer tank formed by the jacket. There may be a distance between the inner cooling container and the jacket of 50-150 mm, which creates a space that may be filled with insulating material.

[0116] According to an eighth aspect, there is provided a method of cooling milk comprising providing a cooling container comprising a heat exchanger as disclosed above or a heat exchanger assembly as disclosed above, providing milk in a product space of said cooling container, allowing a coolant to flow through said heat exchanger or heat exchanger assembly, and stirring the milk by an agitator.

[0117] The coolant may for example be CO 2 . However, any other suitable coolant may be used, such as a natural or synthetic coolant, for example propane, ammonia, or HFC-refrigerants. A lubricant, such as an oil may be mixed with the coolant. The oil may be insoluble with the coolant. Alternatively, the oil may be at least partly soluble with the coolant. The coolant may be at least partly soluble with the oil. The oil may for example be a polyol ester (POE) oil or a polyalkylene glycol (PAG) oil.

[0118] The method may further comprise controlling the flow rate of the coolant. The method may comprise controlling an inverter-driven compressor.

[0119] Below are described further aspects of the present disclosure.

[0120] According to a ninth aspect, there is provided a method for manufacturing a heat-exchanger comprising providing two plate materials, cutting at least one edge portion of one of the two plate materials into a zig-zag shape, joining a peripheral portion of at least one of the plate materials to the other plate material by a seal, and welding the two plate materials together by a weld pattern, including welding a plurality of spots. The zig-zag shape may be provided by a cutting operation before the two plate materials are welded together.

[0121] The method may be used for manufacturing of for example an evaporator. Thus, the heat exchanger may be an evaporator, for example an evaporator for a cooling container for cooling of a liquid, such as for example milk. The method is particularly suitable for production of evaporator plates for large cooling containers, such as milk tanks or milk silos.

[0122] The plate materials, the seal, and / or the weld pattern may be provided as previously described above.

[0123] The edge portion may have a curved periphery before being cut into a zig-zag shape.

[0124] According to a tenth aspect, there is provided a heat exchanger for a cooling container, such as a tank for milk cooling, the heat exchanger comprising a pair of plate materials, an inlet for a coolant, and an outlet for the coolant. A peripheral portion of at least one of the plate materials is joined to the other plate material by a seal such to form a sealed coolant passage space between the plate materials. The pair of plate materials are welded together by a weld pattern, wherein the weld pattern comprises a plurality of welded spots. At least one of the pair of plate materials has a zig-zag shaped edge portion.

[0125] The zig-zag shape may be provided by a zig-zag pattern. The zig-zag pattern may be provided as previously described above. The plate materials, the seal, and / or the weld pattern may be provided as previously described above. The heat exchanger may have the same size and / or shape as previously described above.

[0126] According to an eleventh aspect, there is provided a heat exchanger assembly comprising two heat exchangers according to the tenth aspect, wherein the two heat exchangers are welded together.

[0127] According to a twelfth aspect, there is provided a cooling container comprising a heat exchanger according to the tenth aspect or a heat exchanger assembly according to the eleventh aspect. The cooling container may have the same size and / or shape as previously described above. The cooling container may be designed essentially the same as previously described above.

[0128] According to a thirteenth aspect, there is provided a system comprising a cooling container according to the twelfth aspect. The system may be designed and / or configured essentially the same as previously described in relation to the fifth aspect.

[0129] According to a fourteenth aspect, there is provided a method for manufacturing a cooling container, comprising providing a heat exchanger obtained by the method of the ninth aspect, or a heat exchanger according to the tenth aspect, forming the heat exchanger into a desired shape, and inflating the heat exchanger. The method may be performed as described above in relation to the seventh aspect.

[0130] According to a fifteenth aspect, there is provided a method of cooling milk comprising providing a cooling container comprising a heat exchanger according to the tenth aspect or a heat exchanger assembly according to the eleventh aspect, providing milk in a product space of said cooling container, allowing a coolant to flow through said heat exchanger or heat exchanger assembly, and stirring the milk by an agitator. The method may be performed as described above in relation to the eighth aspect.Brief description of the drawings

[0131] The invention will in the following be described in more detail with reference to the enclosed drawings, wherein: Figs 1a-1c schematically illustrates cooling containers comprising a heat exchanger assembly. Figs 2a-2c schematically illustrates a heat exchanger and a heat exchanger assembly. Figs 3a-3d schematically illustrates enlarged portions of a detailed view of the heat exchanger as illustrated in Figs. 2a-2c. Fig. 3a displays a main portion and an end portion of the welded baffle line, and also schematically illustrates an example of a flow path for a coolant. Fig. 3b displays a main portion and an end portion of the welded baffle line, wherein the end portion has a rounded shape, and also schematically illustrates an example of a flow path for a coolant. Fig. 3c schematically illustrates a plurality of welded spots in a continuous diamond pattern. Fig. 3d schematically illustrates a zig-zag shaped edge portion. Fig. 4 schematically illustrates a cross-sectional view of a heat exchanger. Fig. 5 schematically illustrates a system comprising a cooling container. Figs 6a-6c schematically illustrates a method for manufacturing a heat-exchanger. Detailed description

[0132] The present inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled addressee. Like reference characters refer to like elements throughout.

[0133] The present inventive concept finds use in various types of containers for cooling, such as tanks or silos for cooling of a product.

[0134] The heat exchanger may be an evaporator.

[0135] The heat exchanger may be placed within or as a wall of an inner container space 101 holding the product to be cooled.

[0136] In the following description, the inventive concept will be described with reference to a cooling container 100 in form of a silo for milk cooling, having a heat exchanger comprising a pair of plate materials 2a, 2b, an inlet 12 and an outlet 13 for a coolant.

[0137] The coolant may be CO 2 . However, any other suitable coolant may be used, such as a natural or synthetic coolant, for example propane, ammonia, or HFC-refrigerants.

[0138] A lubricant, such as an oil may be mixed with the coolant. The oil may be insoluble with the coolant. Alternatively, the oil may be at least partly soluble with the coolant. The coolant may be at least partly soluble with the oil. The oil may for example be a polyol ester (POE) oil or a polyalkylene glycol (PAG) oil.

[0139] As illustrated in figs 1a-1c, a silo 100 may comprise a heat exchanger assembly 10 comprising two heat exchangers 1a, 1b for cooling a product stored in the silo 100. The product to be cooled by the heat exchanger assembly 10 may be milk, water, beer or any other beverage or intermediate in production of a beverage. The heat exchanger assembly 10 may be positioned in a bottom part of the silo 100, so as to constitute a bottom wall of a storage space 101, i.e. a product space, within the silo 100. The product being in the vicinity of the heat exchanger assembly 10 may heat exchange with the coolant of the heat exchanger 1a, 1b. To achieve an even more effective cooling of the product, the silo 100 may, according to one embodiment, comprise equipment for agitating the product within the silo 100. For example, the silo may comprise at least one agitator. By agitating the product, a more even cooling of the product may be achieved.

[0140] The heat exchanger assembly 10 may constitute a bottom wall that is conical, in which the walls are tapering in a downwards direction. The bottom part, where a mantle of the conical shape meet, may comprise an outlet for the product, so that the product may be emptied in a convenient way from the silo 100. Further, the silo 100 may comprise an inlet (not shown) for the product. The inlet may be placed in an upper part of the silo 100.

[0141] The heat exchanger assembly 10 may be a centered conical shape, as illustrated in fig. 1b. The heat exchanger assembly 10 may be a skewed conical shape, as illustrated in fig. 1c.

[0142] The silo 100 may have a product volume of 1500-2500 liters, 2500-3500 liters, 3000-4000 liters, 4000-5000 liters, 5000-6000 liters, 6000-7000 liters, 7000-8000 liters, 9000-10 000 liters, 10 000-20 000 liters, 20 000-30 000 liters, 30000-40 000 liters, 40 000-50 000 liters, 50 000-60 000 liters, or 60 000-70 000 liters. The silo 100 may have a height of 2-3, 3-4, 4-5, 5-6, 6-7, 7-8, 8-9 or 9-10 meters. A diameter of the silo 100 may be 1-5 meters, preferably 1.5-4 or 2-3.5 meters.

[0143] As illustrated in figs. 1a-1c, the cooling container may comprise a container wall portion 102. As illustrated, the container wall portion may be cylindrical. However, other shapes and / or sizes are possible. Further, as illustrated, the container wall portion may be joined with the heat exchanger assembly 10.

[0144] Figs 1a-1c illustrate one example of a cooling container in form of a silo. However, it is understood that other shapes and / or sizes of the cooling container is possible. For example, the cooling container may be a horizontal tank, such as a horizontal milk tank.

[0145] Further, although not illustrated, the silo 100 may be provided with an outer jacket. Thus, the silo 100 may form part of an assembly comprising the silo forming an inner cooling container and a jacket forming an outer tank.

[0146] There may be a distance between the silo and the jacket of 50-150 mm, which creates a space that may be filled with insulating material.

[0147] In fig. 2a, a heat exchanger 1a is schematically illustrated. The heat exchanger 1a comprises a pair of plate materials 2a, 2b, wherein a peripheral portion of at least one of the plate materials 2b is joined to the other plate material 2a by a seal 14 such to form a sealed coolant passage space 11 between the plate materials 2a, 2b. The seal 14 may be welded.

[0148] The heat-exchanger 1a, 1b and heat exchanger assembly 10 in figs 2a-2c are illustrated as being substantially flat, wherein both surfaces of the heat exchangers 1a, 1b are substantially flat. When being manufactured, the heat exchanger 1a, 1b may be flat and un-inflated and unpressurized. The heat exchanger 1a, 1b or heat exchanger assembly 10 may at a later stage first be formed to a desired shape and mounted in a cooling container, such as a tank or silo, and then be pressurized and inflated. The heat exchanger 1a, 1b may be mounted in a supporting structure, that supports the heat exchanger 1a, 1b when being inflated so as to keep the desired shape of the heat exchanger 1a, 1b intact. In an alternative embodiment the heat exchanger 1a, 1b or heat exchanger assembly 10 may be pressurized and inflated after being manufactured, and at a later stage being mounted in a cooling container, such as a tank or silo. When the heat exchangers 1a, 1b or heat exchanger assembly 10 are pressurized and inflated, one surface may remain substantially flat and the opposite surface may be deformed. The deformed surface may present a surface having bubble shapes or pillow shapes. The substantially flat surface may be the surface of the plate material 2a, and the deformed surface may be the surface of the plate material 2b.

[0149] The heat exchanger 1a further comprises an inlet 12 for a coolant and an outlet 13 for the coolant. The coolant may be passed through the heat exchanger 1a from the inlet, to the outlet, in order to heat exchange with the surrounding of the heat exchanger 1a.

[0150] The pair of plate materials 2a, 2b are further weld together by a weld pattern 30 comprising a plurality of welded spots 31. The weld pattern may provide an even flow of the coolant through the heat exchanger 1a.

[0151] Further, a flow of coolant through the heat exchanger 1a may be guided in a serpentine pattern across the coolant passage space 11 between the plate materials 2a, 2b by welded baffle lines 32. The welded baffle lines 32 may create a channel within the passage space 11 for the flow of coolant. The heat exchanger 1a may comprise at least one or at least two welded baffle lines 32. The embodiment according to fig. 2a discloses a heat exchanger 1a having four welded baffle lines 32. According to another embodiment (not illustrated), the heat-exchanger may have three, five, six, seven or more welded baffle lines 32.

[0152] The baffle lines 32 comprises a main portion 321 extending in a first direction, and an end portion 322 extending in a second direction being different from the first direction. The main portion 321 may extend as a first straight line. The end portion 322 may connect to the main portion 321 by creating a first angle α between the main portion 321 and the end portion 322, as seen in fig. 3a. The first angle α may be about 80-90° or 90-100° or 100-110° or 110-120° or 120-130° or 130-140° or 140-150° or 150-160°. The end portion 322 may connect at its other end to the seal 14. The end portion 322 may extend as a second straight line or as a curved line. A connection point 141 at which the end portion 322 and seal 14 connects may create a second angle β between the end portion 322 and a tangent T that tangents the connection point 141, as seen in fig. 3a. The second angle β may be about 70-80° or 80-90° or 90-100° or 100-110° or 110-120°.

[0153] A distance S between the main portions 321 of two adjacent welded baffle lines 32 may be about 140-150 mm or 150-160 mm or 160-170 mm or 170-180 mm or 180-190 mm or 190-200 mm or 200-210 mm or 210-220 mm.

[0154] The heat exchanger 1a according to an embodiment of fig. 2a has a half circle-resembling shape. By half circle-resembling shape is meant a shape substantially having the shape of a half circle and having a portion deviating from the half circular shape. The deviating portion may be a cutout portion. In the embodiment of fig. 2a, the main portion 321 of the welded baffle lines 32 may extend parallel to a base of the half circle.

[0155] The plate material 2a according to fig. 2a is shaped as having a circle arc that extends from the base of a half circle in one end, until there is a circle sector having an angle of about 8-12° left until the circle arc would have reached a base line. The base extends from the end connected to the arc and about 65-75% of the distance of a full base line for a half circle. The base comprises a half circular-resembling recess for shaping an outlet of an inner container space. The edge of the plate material 2a then continues in a straight line that meet the arc. The base of the half circle of the plate material 2a may have additional recesses for fixing of at least one agitator and / or at least one temperature sensor. The plate material 2b according to fig. 2a may have essentially the same shape as the plate material 2a, differing in that the arc extends until there is a circle sector having an angle of about 14-18° left until the circle arc would have reached a base line. The base extends in the same direction as the base of the plate material 2a. The extent of the base of the plate material 2a may be larger than the extent of the base of the plate material 2b. The base of the plate material 2b then continues in a quarter circular recess continuing in a substantially straight edge line parallel with an extension of the base, said edge line extends for a distance shorter than a distance needed to reach the arc. An end of the arc and an end of the straight edge line of the recess is then connected by a substantially straight edge line. However, the heat exchangers 1a, 1b are not limited to this shape. The heat exchangers 1a, 1b may be shaped as circles, half circles, squares, rectangles or any other suitable shape.

[0156] An edge portion 20 of at least one of the plate materials 2a, 2b may have a zig-zag shape. The edge portion may have a curved periphery before being cut into a zig-zag shape. The zig-zag shape may be provided by a zig-zag pattern. The zig-zag pattern may be provided along at least a portion of the periphery of the plate material 2a, 2b, preferably along more than 50 % of the periphery, more preferably along more than 75 % or along more than 90 % of the periphery of the plate material.

[0157] In fig. 2a, the edge portion 20 extends over the circle arc, the base, and the straight parts connecting the arc and the base. In an alternative embodiment (not illustrated), only the circle arc has a zig-zag shaped edge portion 20. During welding, the plate material 2a, 2b may shrink and warp, due to the high temperature treatment. By having a zig-zag shaped edge portion 20, the plate materials 2a, 2b may be allowed to shrink without interfering with the design of the heat exchanger 1a, and the risk of warping is decreased.

[0158] Along the base of the half circular heat exchanger there may be a separate channel 15, having an inlet 151 and an outlet 152. In the channel 15, ethanol, glycol or any other coolant may be circulated so as to create a cooled outlet for the product. Thereby, product located at the outlet, which may not be sufficiently cooled by coolant flowing through the coolant passage space 11 can be cooled. When a product is loaded to the inner container space 101 of the cooling container 100, the outlet of the inner container space may be closed, for example by a closing mechanism. However, the closing mechanism of the inner container space can be located within the outlet, thereby allowing a portion of the product to be stored in the beginning of the outlet. The outlet may not be in contact with the heat exchanger 1a, 1b, instead, a separate cooling circuit may cool the product in the outlet. This cooling circuit may be connected to the inlet 151 and the outlet 152 of the channel 15, so that a coolant of said cooling circuit is cooled within the channel 15 by the cooled product.

[0159] The heat exchanger 1a may have a diameter of about 1.5-2 m or 2-2.5 m or 2.5-3 m or 3-3.5 m or 3.5-4 m or 4-4.5 m or 4.5-5 m. In one embodiment, the diameter may be 2.3 m. In another embodiment, the diameter may be 3 m. The heat exchanger 1a may have a surface area of 2-3 m 2< or 3-4 m 2< or 4-5 m 2< or 5-6 m 2< or 6-7 m 2< or 7-8 m 2< .

[0160] The description above of a heat exchanger 1a equally applies to a heat exchanger 1b comprising the same parts but being mirrored to the heat exchanger 1a.

[0161] Fig. 2b schematically illustrates a heat exchanger 1a. The description above in relation to fig. 2a equally applies to the heat exchanger of fig. 2b, except for that the end portion 322 is a curved line, having a radius of about 110 mm.

[0162] Fig. 2c schematically illustrates a heat exchanger assembly 10 comprising a heat exchanger 1a and a heat exchanger 1b. The heat exchangers 1a, 1b and the parts illustrated in fig. 2c may have the same functions and features as described above in connection to fig. 2a or fig. 2b.

[0163] The heat exchangers 1a, 1b may be welded together along the base of the respective half circle. In fig. 2c, the heat exchanger assembly 10 is illustrated flat. A flat heat exchanger assembly 10 may be used, for example in a cylindrical milk tank. The heat exchanger assembly 10 may be shaped so as to be conical, as illustrated in figs 1a-1c, and used in a silo as a bottom portion of an inner storage space of a silo for cooling milk.

[0164] Fig. 3a-d schematically illustrates enlarged portions of detailed views of a heat exchanger 1a, 1b. The main part 321 of the welded baffle line 32 may be welded along a row of welded spots 31. In fig. 3a, the main portion 321 may be substantially straight, and extending parallel to the base of a half circular heat exchanger 1a, 1b. The end portion 322 may connect to one end of the main portion 321, thereby creating a first angle α between the main portion 321 and the end portion 322. The first angle α may be about 80-90° or 90-100° or 100-110° or 110-120° or 120-130° or 130-140° or 140-150° or 150-160°. According to the embodiment of fig. 3a, the first angle α is about 130-140°.

[0165] The end portion 322 may be substantially straight. The end portion 322 may extend so as to connect to the seal 14. As may be seen in fig. 3a, the end portion 322 may extend past the seal 14, so as to intersect the seal 14. By extending past the seal 14, the welded lines provide a robust channel with minimum risk for a leakage between lines and thereby preventing creating bypass channels for the coolant.

[0166] In an alternative embodiment, the end portion 322 may be curved so as to have a radius, as illustrated in fig. 3b. All other features described in connection to fig. 3a equally applies to the heat exchanger of fig. 3b.

[0167] The seal 14 may comprise two welded lines. Thereby, the seal 14 creates a more robust welded line, if one line is failing, the heat exchanger 1a, 1b is still sealed from the outer surroundings, and the coolant is kept within the sealed coolant passage space 11.

[0168] According to the embodiment of fig. 3a, the plate material 2a is of larger dimensions than the plate material 2b. The peripheral portion of the plate material 2b is joined to the plate material 2a, thereby leaving a larger part of the plate material 2a protruding from the seal 14 than on the plate material 2b.

[0169] As seen in fig 3a-3c, the welded spots 31 may form a continuous diamond pattern. As illustrated in fig. 3c, the diamond pattern may have a first distance D 1 between the spots 31 in a first direction and a second distance D 2 in second direction, wherein the first and the second directions are perpendicular to each other. The first distance D 1 may be 15-20 mm or 20-25 mm or 25-30 mm or 30-35 mm. The second distance D 2 may be 30-35 mm or 35-40 mm or 40-45 mm or 45-50 mm or 50-55 mm or 55-60 mm. According to the embodiment of figs. 3a-3c, the first distance D 1 may be 22-26 mm and the second distance D 2 may be 40-44 mm.

[0170] The coolant may flow in between the welded spots 31. The welded spots 31 may enable a swirling flow, thereby achieving a good mixing of the coolant and an even flow of the coolant through the sealed coolant space 11. The coolant may flow in a swirling way around the welded spots 31, as seen in fig. 3a, taking different directions, but resulting in a net flow as illustrated in figs. 2a-b.

[0171] Further, at least one of the pair of plate materials 2a, 2b may have a zig-zag shaped edge portion 20. As seen in fig. 3a, the plate material 2b has a zig-zag shaped edge portion 20. The zig-zag shaped edge portion 20 of the plate material 2b is positioned on the plate material 2a. The plate materials 2a, 2b as illustrated in fig. 3a are joined together by a welded seal 14.

[0172] As illustrated in fig. 3d, the zig-zag shape may be a pattern comprising a plurality of triangles having a height H. The height may be 3-15 mm, preferably 5-13 mm or 7-11 mm. The triangles of the zig-zag shape pattern may have an internal angle δ of 30-40° or 40-50° or 50-60° or 60-70° or 70-80° or 80-90° or 90-100° or 100-110° or 110-120°.

[0173] Fig. 4 schematically illustrates a cross-sectional view of a heat exchanger 1a, 1b, after the heat exchanger 1a, 1b has been pressurized and inflated. The heat exchanger 1a, 1b may be a single-embossed pillow plate. The description of the heat exchanger 1a, 1b above, equally applies to the heat exchanger 1a, 1b in fig. 4. The pair of plate materials 2a, 2b may be of different thickness. The plate material 2a may be thicker than the plate material 2b.

[0174] The welded spots 31 creates spots or areas where the plate materials 2a, 2b are joined together, so that when pressurizing and inflating the heat exchanger 1a, 1b, the inflated areas create the pillow plate structure. When pressurizing and inflating the heat exchanger 1a, 1b, the sealed coolant passage space 11 may be inflated so that a coolant may pass through the space 11.

[0175] Fig. 5 schematically illustrates a system comprising a heat exchanger. The system may comprise a cooling container 100, a compressor 200, a gas cooler 300 and an expansion valve 400. The coolant may flow through the system. In the cooling container, the coolant may pass through a heat exchanger 1a, 1b or a heat exchanger assembly 10, as described above in relation to figs. 1-4. The coolant heat exchange to a product stored in the cooling container 100, so that the coolant cools the product. Thereby, the coolant has a higher temperature when leaving the cooling container 100 than before entering the cooling container 100. The coolant may also have transformed from one phase to another, for example from liquid phase to vapor phase. The coolant may then flow to the compressor 200, which may compress the coolant so that pressure is raised. The temperature may be raised when compressing the coolant. Further, the coolant flows through the gas cooler 300, in which the temperature of the coolant is lowered, while the pressure is maintained. The gas cooler 300 may heat exchange the coolant with ambient air, surrounding the gas cooler 300. The coolant may change phase after treatment in the gas cooler 300, for example, the coolant may transform from vapor phase to liquid phase. The coolant may flow through the expansion valve 400. The expansion valve 400 restricts the flow of coolant to the cooling container 100, thereby may the pressure of the coolant be lowered before the coolant reaches the cooling container 100.

[0176] The system may be an inverter-driven system, so as to be a frequency-driven system. Thus, the system may be configured such to control and adjust a flow rate, or speed, of the coolant in the system.

[0177] The system may further comprise a controller (not illustrated) for controlling the flow rate of coolant within the system. The system may control the compressor 200 so that the flow of coolant may be higher or lower, thereby adjusting the cooling effect of the heat exchanger assembly 10.

[0178] The cooling container 100 may comprise a heat exchanger assembly 10 having a heat exchanger 1a and a heat exchanger 1b. The compressor 200, the gas cooler 300 and the expansion valve 400 may then supply coolant to both heat exchangers 1a, 1b, wherein the heat exchangers 1a, 1b are coupled in parallel. Alternatively, each heat exchanger 1a, 1b may be coupled to its own circuit comprising a compressor 200, a gas cooler 300 and an expansion valve 400.

[0179] Figs. 6a-6c schematically illustrates a method for manufacturing a heat-exchanger. The method may be used to produce a heat exchanger as described above in relation to figs. 2-3. The method may comprise providing S1 two plate materials, cutting S2 at least one edge portion of one of the two plate materials into a zig-zag shape, joining S3 a peripheral portion of at least one of the plate materials to the other plate material by a seal, and welding S4 the two plate materials together by a weld pattern, including welding a plurality of spots. The seal may be provided by welding. The seal may be formed by seam welding, such as laser seam welding. The weld pattern may be provided by laser welding. The spots may be formed by spot welding, such as laser spot welding. The method may comprise, after the cutting step S2, aligning the plate materials so that a surface of each plate material is facing each other. The step S4 may further comprise welding at least one baffle line. The at least one baffle line may be provided by laser welding.

[0180] The step S3 of joining a peripheral portion of at least one of the plate materials to the other plate material by a seal, and the step of welding S4 the two plate materials together by a weld pattern may be performed separately or simultaneously. As one example, the step of welding the two plate materials together by a weld pattern may be performed after the seal is provided, see fig. 6a. Alternatively, the seal may be provided after the weld pattern, see fig. 6b. Alternatively, the seal and weld pattern may be provided simultaneously, see fig. 6c. In step S4, the spots and at least one baffle line may be provided simultaneously or as sub-steps. Thus, the spots may be provided before said at least one baffle line. Alternatively, the at least one baffle line may be provided before said spots. The weld pattern may be provided as described above in relation to figs. 2-3.

[0181] Further, the heat exchanger as described above in relation to figs. 2-3 or as obtained by the method as described in relation to figs. 6a-6c may be used to produce a cooling container, for example a cooling container as described in relation to fig. 1a-1c and fig. 5. A method for manufacturing a cooling container can comprising providing said heat exchanger, forming the heat exchanger into a desired shape, and inflating the heat exchanger. After inflation, the heat exchanger may present the form as illustrated in fig. 4. The desired shape of the heat exchanger may for example be conical or cylindrical. The method may comprise joining the heat exchanger to a cooling container portion for forming the cooling container. For example, the method may comprise joining the heat exchanger to a container wall portion. The joining may be performed by welding. Joining the heat exchanger to another cooling container portion may be performed before the inflation of the heat exchanger. Joining the heat exchanger to another cooling container portion may be performed after the heat exchanger has been formed into the desired shape. The container wall portion may form a support structure for the heat exchanger when being inflated. The support structure enables inflation of the heat exchanger, such to form the pillow structure of the heat exchanger, while also ensuring that the heat exchanger maintain the desired shape. Alternatively, a separate support structure, different from the container wall portion, may be provided. The support structure may have essentially the same shape as said desired shape of the heat exchanger. Thus, the heat exchanger may be placed within the support structure before being inflated.

[0182] Further, the step of forming the heat exchanger may comprise joining the heat exchanger to another heat exchanger by welding, such to form a heat exchanger assembly, for example as described above in relation to fig. 1a-1c and fig. 2c. The step of forming the heat exchanger may comprise forming the heat exchanger or heat exchanger assembly into a conical-shaped end portion of the product space of the cooling container, as illustrated in figs 1b-1c. The forming may comprise bending the heat exchanger or heat exchanger assembly, i.e. the pair of plate materials that are welded together may be processed, such as in a bending process, into the desired shape. The method may further comprise joining the cooling container with a jacket (not illustrated).

[0183] The heat exchanger, heat exchanger assembly, cooling container and / or system as described above in relation to figs. 1-5 may be used in a method of cooling a liquid, such as for example milk. Thus, a method of cooling milk may comprise providing a cooling container comprising a heat exchanger as disclosed above or a heat exchanger assembly as disclosed above, providing the liquid, such as milk, in a product space of said cooling container, allowing a coolant to flow through said heat exchanger or heat exchanger assembly, and stirring the liquid by an agitator.

Examples

Embodiment Construction

[0132]The present inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled addressee. Like reference characters refer to like elements throughout.

[0133]The present inventive concept finds use in various types of containers for cooling, such as tanks or silos for cooling of a product.

[0134]The heat exchanger may be an evaporator.

[0135]The heat exchanger may be placed within or as a wall of an inner container space 101 holding the product to be cooled.

[0136]In the following description, the inventive concept will be described with reference to a cooling container 100 in form of a silo for milk cool...

Technical field

[0001] The present disclosure relates to a heat exchanger, in particular for a cooling container, such as a tank for milk cooling. Further is also a method for manufacturing a heat exchanger disclosed.

[0002] The disclosure also relates to a heat exchanger assembly, a cooling container comprising a heat exchanger or a heat exchanger assembly, to a system comprising a cooling container, to a method for manufacturing a cooling container, and to a method for cooling milk by a cooling container.Background

[0003] In dairy production, hygiene and efficient utilization of milk already on the farm are important, to fulfill requirements for food production. At farms, large tanks or silos are used for storing milk produced before the milk is transported to dairies. Different environments and different amount of milk in a tank or silo require different efficiency of the cooling equipment. The milk is preferably to be kept at a constant temperature around 3°C, and not to higher or lower than this.

[0004] In cooling circuits of such tanks and silos, it has commonly been used coolants that are hazardous and not environmentally friendly. These coolants are to be phased out of the market, and replaced with more environmentally friendly coolants. However, some of these coolants, for example CO 2 , requires a much higher pressure, which put needs on the construction of the cooling circuits and heat exchangers.

[0005] Heat exchangers are commonly placed in the bottom of a tank or silo for cooling the milk. The milk is agitated in the tank or silo to get a good cooling of the milk. In a silo, circular heat exchangers are often used, to be able to cover the whole bottom surface of the silo. However, these circular heat exchangers are more complicated to manufacture than a rectangular heat exchanger.

[0006] Further, in cooling systems, lubrication of the compressor is important for the service life of the compressor and for high performance of the cooling system. However, oil may be carried with the coolant to other parts of the cooling system. There is a problem of oil being lost over time and not being efficiently returned to the compressor. Without sufficient oil return, the compressor may break. Accumulation of oil in any part of the cooling system may result in decreased cooling efficiency. It is known to use an oil separator to reduce the risk of oil accumulation. However, an oil separator may not fully eliminate the risk of oil accumulation in the system. Thus, efficient oil return is desirable, both for the service life of the compressor and for a secure and reliable cooling system.

[0007] It is therefore needed a new and improved heat exchanger and cooling system to alleviate at least some of above mentioned problems.Summary

[0008] It is an object of the present disclosure to provide an improved solution that alleviates at least some of the above mentioned drawbacks with present solutions. In particular, there is an object to provide an improved heat exchanger, heat exchanger assembly, cooling container and / or cooling system having an improved cooling efficiency and / or improved oil return. There is a further object to provide an improved method for manufacturing a heat exchanger and / or cooling container.

[0009] The invention is defined by the appended independent claims, with embodiments being set forth in the appended dependent claims, in the following description and in the drawings.

[0010] According to a first aspect, there is provided a heat exchanger for a cooling container, such as a tank for milk cooling, the heat exchanger comprising a pair of plate materials, an inlet for a coolant, and an outlet for the coolant. A peripheral portion of at least one of the plate materials is joined to the other plate material by a seal such to form a sealed coolant passage space between the plate materials. The pair of plate materials are welded together by a weld pattern, wherein the weld pattern comprises a plurality of welded spots. The weld pattern comprises at least one welded baffle line for directing a flow of coolant from the inlet to the outlet when in use, wherein the welded baffle line comprises a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0011] The heat exchanger is suitable for use as an evaporator. Thus, the heat exchanger may be an evaporator for a cooling container for cooling of a liquid, such as for example milk. The heat exchanger is particularly suitable for use as an evaporator for large cooling containers, such as milk tanks or milk silos.

[0012] The heat exchanger plate may be formed as a pillow plate, preferably a single-embossed pillow plate. Thus, as seen after an inflation-process used to form a "pillow-shaped" surface of the heat exchanger, one side of the plates welded together may be flat. The other side may be deformed. The flat side may form a product face, i.e. a surface adapted to be in contact with a product, such a milk. Thus, the flat side may be adapted to form an inner surface of a cooling container.

[0013] The pair of plate materials may be provided in form of two metal plates. The pair of plate materials may be made of any suitable metal or metal alloy, preferably stainless steel. One of the pair of plate materials may present a first thickness. The other one of pair of plate materials may present a second thickness. The first and second thicknesses may vary. Thus, the pair of plate materials may have a varying thickness in relation to one another. The size and shape of the two metal plates may vary.

[0014] Alternatively, the size and shape of the two metal plates may be essentially the same.

[0015] The coolant passage space formed between the plate materials may be configured to allow a flow of coolant through the space, from the inlet to the outlet of the heat exchanger, when in use.

[0016] The heat exchanger may have an at least partly curved periphery.

[0017] Said seal may be provided in form of a welded seal. Thus, the pair of plate materials may be welded together by a welded seal extending along an edge portion of at least one of the plates. The seal may be formed by seam welding, such as laser seam welding.

[0018] The welded spots may form a spot pattern. The spots may be formed by spot welding, such as laser spot welding.

[0019] The seal can be seen to extend such to encompass said weld pattern. Thus, the seal can be seen as an outermost limit of said weld pattern.

[0020] The seal can comprise at least one curved portion.

[0021] The at least one welded baffle line may be provided for directing a flow of coolant in a meandering path, from the inlet to the outlet.

[0022] The heat exchanger may comprise a plurality of welded baffle lines. A space between two adjacent welded baffle lines may be seen to form a channel. For example, a space between a first welded baffle line and an adjacent second welded baffle line can be seen to form a first channel for passing a flow of coolant in a first direction. The first channel can open up into a turning zone. The turning zone can be seen as a space wherein the flow is forced to change direction. A space between the second welded baffle line and an adjacent third welded baffle line can be seen to form a second channel for passing a flow of coolant in a second direction, opposite to the first direction of the first channel. The second channel may open up into another turning zone.

[0023] The coolant may be a cooling medium or refrigerant in liquid or gas phase configured to be transported between the pair of plates. The coolant may transform between liquid and gas phase while heat-exchanging in the heat exchanger, or the coolant will be in the same phase, liquid or gas, while heat-exchanging in the heat exchanger.

[0024] The heat exchanger according to the above may preferably be used with a coolant in form of CO2. However, the heat exchanger may be used with any suitable coolant, such as for example a natural or a synthetic refrigerant.

[0025] When in use, a lubricant, such as an oil may be mixed with the coolant and flow with the coolant of the system. The oil may be insoluble with the coolant. Alternatively, the oil may be at least partly soluble with the coolant. The coolant may be at least partly soluble with the oil. The oil may for example be a polyol ester (POE) oil or a polyalkylene glycol (PAG) oil.

[0026] The heat exchanger according to the above allows for an improved cooling efficiency. Further, the heat exchanger according to the above reduces the risk of oil clogging or oil accumulation in the heat exchanger and allows for an improved oil return.

[0027] Said end portion of the welded baffle line may be located in a turning zone of the heat exchanger. According to one example, all turning zones may comprise an end portion of a welded baffle line, said end portion extending in a second direction being different from the first direction of a main portion of the welded baffle line.

[0028] Said end portion of the welded baffle line may be located between the inlet and the outlet, as seen along a flow path for the coolant. The flow path can be determined by the at least one welded baffle line for directing a flow of coolant from the inlet to the outlet. Thus, when in use, the coolant may pass said end portion when the coolant flows from the inlet towards the outlet.

[0029] The weld pattern may comprise two welded baffle lines for directing a flow of coolant from the inlet to the outlet when in use, wherein the two welded baffle lines each comprises a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0030] The weld pattern may comprise three, four, or five welded baffle lines for directing a flow of coolant from the inlet to the outlet when in use, wherein the three, four, or five welded baffle lines each comprises a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0031] The weld pattern may comprise a first welded baffle line and an adjacent second welded baffle line, wherein the first welded baffle line and the second welded baffle line form a channel for passing a flow of coolant between a first turning zone and a second turning zone, wherein each one of the first and second welded baffle lines comprises a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0032] The weld pattern may comprise a plurality of welded baffle lines, wherein at least two, at least three, at least four, or at least five of said plurality of welded baffle lines each comprises a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0033] The weld pattern may comprises a plurality of welded baffle lines for directing a flow of coolant from the inlet to the outlet, wherein at least 40 %, preferably at least 50 %, at least 60 % or at least 75 %, of the plurality of welded baffle lines each comprises a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0034] Thus, according to one example, a majority of the plurality of welded baffle lines may comprise a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction. By "majority" is meant more than 50 % of the total amount of welded baffle lines that are provided for directing a flow of coolant from the inlet to the outlet when in use. As one example, all of the welded baffle lines that are provided for directing a flow of coolant from the inlet to the outlet may each comprise a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0035] A first angle between the main portion and the end portion may be 80-160°, preferably 90-150° or 110-140°.

[0036] The main portion may extend as a first straight line.

[0037] The end portion may extend as a second straight line or as a curved line.

[0038] Said end portion may be connected to said seal.

[0039] Thus, a first end of said end portion is connected to the main portion of the welded baffle line. A second end of said end portion may be connected to the seal.

[0040] A second angle between the end portion and a tangent that tangents a connection point at which the end portion and seal connects, may be 70-120°, preferably 75-110° or 90-100°.

[0041] The end portion may intersect said seal.

[0042] Thus, the end portion may intersect and extend pass said seal. Thus, a second end of said end portion may be located closer to an outermost edge of said peripheral portion of at least one of the plate materials, than said seal.

[0043] Thereby a heat exchanger with improved quality and / or improved strength can be provided.

[0044] The weld pattern may comprise at least two welded baffle lines, wherein a distance between the main portions of two adjacent welded baffle lines may be 140-220 mm, or 150-215 mm, preferably 170-210 mm or 180-200 mm.

[0045] The plurality of welded spots may form a continuous diamond pattern having a first distance between the spots in a first direction and a second distance in second direction, wherein the first and the second directions may be perpendicular to each other. The first distance may be 15-35 mm, preferably 20-30 mm, and the second distance may be 30-60 mm, preferably 40-55 mm.

[0046] At least one of the pair of plate materials may have a zig-zag shaped edge portion.

[0047] The zig-zag shape may be provided by a zig-zag pattern. The zig-zag pattern may be provided along at least a portion of the periphery of the plate material, preferably along more than 50 % of the periphery, more preferably along more than 75 % or along more than 90 % of the periphery of the plate material. The zig-zag pattern may be substantially regular along said at least a portion of the periphery of the plate material. The zig-zag pattern may comprise a plurality of triangles having a height of 3-15 mm, preferably 5-13 mm or 7-11 mm. Thus, a radial extent of said zig-zag pattern may be 3-15 mm, preferably 5-13 mm or 7-11 mm. The zig-zag pattern may have an internal angle of 30-120°, preferably 35-90° or 40-60°.

[0048] The zig-zag shape may be provided in form of a cut zig-zag pattern provided along at least a portion of the periphery of the plate material. Thus, the zig-zag shape may be provided by a cutting operation before the pair of plate materials are welded together.

[0049] The zig-zag shape may enable joining the plate materials together. In particular, the zig-zag shape prevents undesirable displacement of the plate materials relative to one another during the step of providing the seal. The zig-zag shape can enable welding the plate materials together. Furthermore, it can release stresses of the plate materials and prevent breakage of the seal, thus allowing for a heat exchanger with improved quality and / or strength. By having a zig-zag shaped edge portion, the plate materials may be allowed to shrink without interfering with the design of the design of the heat exchanger, and the risk of warping is decreased.

[0050] The weld pattern may comprise at least two welded baffle lines, wherein at least a portion of the respective main portions of the at least two welded baffle lines are parallel to one another.

[0051] The heat exchanger may have a substantially circular, semicircular or crescent shape.

[0052] The heat exchanger may have a diameter of 1.5-5 m, preferably 2-3.5 m.

[0053] The heat exchanger may have a surface area of 2-8 m 2< , preferably 3-6 m 2< .

[0054] A first side of the heat exchanger may present a substantially flat surface, and an opposite second side of the heat exchanger may present a substantially flat surface.

[0055] Thus, the heat exchanger may be uninflated i.e. the pair of plate materials may be substantially flat and not deformed.

[0056] Alternatively, a first side of the heat exchanger may present a substantially flat surface, and an opposite second side of the heat exchanger may present a deformed surface.

[0057] Thus, the heat exchanger may be inflated. I.e. one of the pair of plate materials may be substantially flat and the other one may be deformed.

[0058] According to a second aspect, there is provided a heat exchanger for a cooling container, such as a tank for milk cooling, the heat exchanger comprises a pair of plate materials, an inlet for a coolant, and an outlet for the coolant. A peripheral portion of at least one of the plate materials is joined to the other plate material by a seal such to form a sealed coolant passage space between the plate materials. The pair of plate materials are welded together by a weld pattern, wherein the weld pattern comprises a plurality of welded spots. The weld pattern comprises two welded baffle lines for directing a flow of coolant from the inlet to the outlet when in use, wherein a distance between the two welded baffle lines is 140-220 mm or 150-215 mm, preferably 170-210 mm or 180-200 mm.

[0059] The heat exchanger is suitable for use as an evaporator. Thus, the heat exchanger may be an evaporator for a cooling container for cooling of a liquid, such as for example milk. The heat exchanger is particularly suitable for use as an evaporator for large cooling containers, such as milk tanks or milk silos. Unless stated otherwise, the heat exchanger may be designed and / or configured essentially the same as the heat exchanger as described in relation to the first aspect.

[0060] The two welded baffle lines may be parallel to one another.

[0061] Each of the two welded baffle lines may comprise a main portion extending in a first direction. Thus, a distance between the main portions of the two welded baffles lines may be 140-220 mm or 150-215 mm, preferably 170-210 mm or 180-200 mm. Further, each of the two welded baffle lines may comprise an end portion extending in a second direction. The second direction may be the same or different from the first direction.

[0062] The heat exchanger according to the second aspect may preferably be used with a coolant in form of CO 2 . However, the heat exchanger may be used with any suitable coolant, such as for example a natural or a synthetic refrigerant.

[0063] When in use, a lubricant, such as an oil may be mixed with the coolant and flow with the coolant of the system. The oil may be insoluble with the coolant. Alternatively, the oil may be at least partly soluble with the coolant. The coolant may be at least partly soluble with the oil. The oil may for example be a polyol ester (POE) oil or a polyalkylene glycol (PAG) oil.

[0064] The heat exchanger according to the second aspect allows for an improved cooling efficiency.

[0065] The plurality of welded spots may form a continuous diamond pattern having a first distance between the spots in a first direction and a second distance in second direction, wherein the first and the second directions are perpendicular to each other. The first distance may be 15-35 mm, preferably 20-30 mm, and the second distance may be 30-60 mm, preferably 40-55 mm.

[0066] A first side of the heat exchanger may present a substantially flat surface, and an opposite second side of the heat exchanger may present a substantially flat surface.

[0067] Thus, the heat exchanger may be uninflated, i.e. the pair of plate materials may be substantially flat and not deformed.

[0068] Alternatively, a first side of the heat exchanger may present a substantially flat surface, and an opposite second side of the heat exchanger may present a deformed surface.

[0069] Thus, the heat exchanger may be inflated. I.e. one of the pair of plate materials may be substantially flat and the other one may be deformed.

[0070] According to a third aspect, there is provided a heat exchanger assembly comprising two heat exchangers as disclosed above, wherein the two heat exchangers are welded together.

[0071] The two heat exchangers may be welded together along a center line.

[0072] In the case of the heat exchangers having a substantially semicircular shape, the two heat exchangers may be welded together to form a substantially circular shape. The pair of plate materials may be bent. For example, the heat exchanger assembly may be formed so as to have a conical shape. The conical shape may be centered, or the conical shape may be shifted so that the mantle area is not uniformly shaped.

[0073] According to a fourth aspect, there is provided a cooling container comprising a heat exchanger as disclosed above or a heat exchanger assembly as disclosed above.

[0074] The cooling container may be a tank for cooling of a liquid, such as milk.

[0075] The cooling container may have an inner container space having a product volume of 1500-70 000 liter.

[0076] The cooling container may be a vertical cooling tank, such as a silo. For example, the cooling container may have a height of 2-10 meters. A diameter of the cooling container may be 1-5 meters, preferably 1.5-4 or 2-3.5 meters.

[0077] Alternatively, the cooling container may be a horizontal tank. For example, the cooling container may have a length of 2-10 meters. A height of the horizontal tank may for example be 1.5-3.5 meters. A width of the horizontal tank may for example be 1-3 meters.

[0078] The cooling container may comprise an agitator arranged inside the container for stirring of a liquid, when the liquid is placed in the container.

[0079] The heat exchanger or heat exchanger assembly may be arranged at a bottom portion of the cooling container.

[0080] The heat exchanger or heat exchanger assembly may present a surface forming an inner surface of the cooling container.

[0081] For example, the heat exchanger or heat exchanger assembly may present a surface forming an inner bottom surface of the cooling container. The surface of the heat exchanger or heat exchanger assembly forming the inner surface of the cooling container may be substantially flat.

[0082] According to a fifth aspect, there is provided a system comprising a cooling container as disclosed above, and a coolant.

[0083] The coolant may be anyone chosen from a group of CO 2 , propane, ammonium or a HFC refrigerant.

[0084] The heat exchanger may be used with any suitable coolant, such as for example a natural or a synthetic refrigerant.

[0085] A lubricant, such as an oil may be mixed with the coolant. The oil may be insoluble with the coolant. Alternatively, the oil may be at least partly soluble with the coolant. The coolant may be at least partly soluble with the oil. The oil may for example be a polyol ester (POE) oil or a polyalkylene glycol (PAG) oil.

[0086] The system may be an inverter-driven system.

[0087] The system may also be referred to as a frequency-driven system. Thus, the system may be configured such to control and adjust a flow rate of the coolant in the system.

[0088] The system may further comprise a controller, and a compressor, wherein the controller is configured to control the compressor.

[0089] The controller may control the compressor so that the compressor causes a flow of the coolant through the heat exchanger. The controller may control the flow so that the flow of the coolant may be varied in speed.

[0090] The compressor may be a variable speed compressor.

[0091] The variable speed compressor may also be referred to as an inverter compressor or inverter-driven compressor.

[0092] According to a sixth aspect, there is provided a method for manufacturing a heat exchanger comprising providing two plate materials, joining a peripheral portion of at least one of the plate materials to the other plate material by a seal, and welding the two plate materials together by a weld pattern, including: welding a plurality of spots, and welding at least one baffle line, wherein the at least one baffle line is welded such to comprise a main portion extending in a first direction, and an end portion extending in a second direction being different from the first direction.

[0093] The method may be used to manufacture a heat exchanger as described above.

[0094] The plate materials can be seen to be joined together so as to form a body of the heat exchanger.

[0095] The seal may be provided such to form a sealed coolant passage space between the plate materials.

[0096] The seal may be provided by welding. Thus, said seal may be provided in form of a welded seal. Thus, the pair of plate materials may be welded together by a welded seal extending along an edge portion of at least one of the plates. The seal may be formed by seam welding, such as laser seam welding. The seal may comprise at least one curved portion.

[0097] The weld pattern may be provided by laser welding.

[0098] The welded spots may form a spot pattern. The spots may be formed by spot welding, such as laser spot welding.

[0099] The at least one baffle line may be provided by laser welding.

[0100] The method may comprise aligning the plate materials so that a surface of each plate material is facing each other before the joining the plate materials.

[0101] The step of joining a peripheral portion of at least one of the plate materials to the other plate material by a seal, and the step of welding the two plate materials together by a weld pattern may be performed separately or simultaneously. As one example, the step of welding the two plate materials together by a weld pattern may be performed before the seal is provided. Alternatively, the seal may be provided before the weld pattern.

[0102] As one example, welding the plurality of spots may be performed before welding the at least one baffle line, which may be performed before joining the peripheral portion of the at least one of the plate materials to the other plate material by a seal. Alternatively, welding the plurality of spots may be performed before joining the peripheral portion of the at least one of the plate materials to the other plate material by a seal, which may be performed before welding the at least one baffle line. Alternatively, two or more of welding the plurality of spots, joining a peripheral portion of the at least one of the plate materials, and welding the at least one baffle line may be performed simultaneously.

[0103] The method may further comprise cutting at least one edge portion of one of the two plate materials into a zig-zag shape.

[0104] The cutting may be performed before the joining of the two plate materials. Thus, said joining may comprise joining a peripheral portion of the plate material comprising the edge portion that has been cut into a zig-zag shape, to the other plate material by the seal.

[0105] At least one of the two plate materials may have at least one edge being curved. The curved edge may be cut into the zig-zag shape in said cutting step.

[0106] According to a seventh aspect, there is provided a method for manufacturing a cooling container, comprising providing a heat exchanger obtained by the method as disclosed above, or a heat exchanger as disclosed above, forming the heat exchanger into a desired shape, and inflating the heat exchanger.

[0107] The method may be used to form a cooling container as described above.

[0108] The desired shape may be for example be conical or cylindrical.

[0109] The method may comprise joining the heat exchanger to a cooling container portion for forming the cooling container. For example, the method may comprise joining the heat exchanger to a container wall portion. The heat exchanger and container wall portion may define an inner container space for the product, i.e. an inner product space. The container wall portion may have a substantially cylindrical form. The container wall portion may form a main body of the cooling container. The joining may be performed by welding. Joining the heat exchanger to another cooling container portion may be performed before the inflation of the heat exchanger. Joining the heat exchanger to another cooling container portion may be performed after the heat exchanger has been formed into the desired shape. The container wall portion may form a support structure for the heat exchanger when being inflated. The support structure enables inflation of the heat exchanger, such to form the pillow structure of the heat exchanger, while also ensuring that the heat exchanger maintain the desired shape. Alternatively, a separate support structure, different from the container wall portion, may be provided. The support structure may have essentially the same shape as said desired shape of the heat exchanger. Thus, the heat exchanger may be placed within the support structure before being inflated.

[0110] Further, the step of forming the heat exchanger may comprise joining the heat exchanger to another heat exchanger by welding, such to form a heat exchanger assembly.

[0111] The step of forming the heat exchanger may comprise forming the heat exchanger or heat exchanger assembly into a conical-shaped end portion of the cooling container.

[0112] Thus, the heat exchanger or heat exchanger assembly may form a bottom portion of the product space of the cooling container.

[0113] The forming may comprise bending the heat exchanger or heat exchanger assembly, i.e. the pair of plate materials that are welded together may be processed, such as in a bending process, into the desired shape.

[0114] Thus, the heat exchanger may be formed into a cooling container or a portion of a cooling container, such as a bottom portion and / or a wall portion of the cooling container.

[0115] The method may further comprise joining the cooling container with a jacket. Thus, the cooling container may form an inner part, such as an inner cooling container, of a cooling tank assembly or cooling silo assembly. Thus the assembly may be seen to comprise an inner cooling container for holding the product, and an outer tank formed by the jacket. There may be a distance between the inner cooling container and the jacket of 50-150 mm, which creates a space that may be filled with insulating material.

[0116] According to an eighth aspect, there is provided a method of cooling milk comprising providing a cooling container comprising a heat exchanger as disclosed above or a heat exchanger assembly as disclosed above, providing milk in a product space of said cooling container, allowing a coolant to flow through said heat exchanger or heat exchanger assembly, and stirring the milk by an agitator.

[0117] The coolant may for example be CO 2 . However, any other suitable coolant may be used, such as a natural or synthetic coolant, for example propane, ammonia, or HFC-refrigerants. A lubricant, such as an oil may be mixed with the coolant. The oil may be insoluble with the coolant. Alternatively, the oil may be at least partly soluble with the coolant. The coolant may be at least partly soluble with the oil. The oil may for example be a polyol ester (POE) oil or a polyalkylene glycol (PAG) oil.

[0118] The method may further comprise controlling the flow rate of the coolant. The method may comprise controlling an inverter-driven compressor.

[0119] Below are described further aspects of the present disclosure.

[0120] According to a ninth aspect, there is provided a method for manufacturing a heat-exchanger comprising providing two plate materials, cutting at least one edge portion of one of the two plate materials into a zig-zag shape, joining a peripheral portion of at least one of the plate materials to the other plate material by a seal, and welding the two plate materials together by a weld pattern, including welding a plurality of spots. The zig-zag shape may be provided by a cutting operation before the two plate materials are welded together.

[0121] The method may be used for manufacturing of for example an evaporator. Thus, the heat exchanger may be an evaporator, for example an evaporator for a cooling container for cooling of a liquid, such as for example milk. The method is particularly suitable for production of evaporator plates for large cooling containers, such as milk tanks or milk silos.

[0122] The plate materials, the seal, and / or the weld pattern may be provided as previously described above.

[0123] The edge portion may have a curved periphery before being cut into a zig-zag shape.

[0124] According to a tenth aspect, there is provided a heat exchanger for a cooling container, such as a tank for milk cooling, the heat exchanger comprising a pair of plate materials, an inlet for a coolant, and an outlet for the coolant. A peripheral portion of at least one of the plate materials is joined to the other plate material by a seal such to form a sealed coolant passage space between the plate materials. The pair of plate materials are welded together by a weld pattern, wherein the weld pattern comprises a plurality of welded spots. At least one of the pair of plate materials has a zig-zag shaped edge portion.

[0125] The zig-zag shape may be provided by a zig-zag pattern. The zig-zag pattern may be provided as previously described above. The plate materials, the seal, and / or the weld pattern may be provided as previously described above. The heat exchanger may have the same size and / or shape as previously described above.

[0126] According to an eleventh aspect, there is provided a heat exchanger assembly comprising two heat exchangers according to the tenth aspect, wherein the two heat exchangers are welded together.

[0127] According to a twelfth aspect, there is provided a cooling container comprising a heat exchanger according to the tenth aspect or a heat exchanger assembly according to the eleventh aspect. The cooling container may have the same size and / or shape as previously described above. The cooling container may be designed essentially the same as previously described above.

[0128] According to a thirteenth aspect, there is provided a system comprising a cooling container according to the twelfth aspect. The system may be designed and / or configured essentially the same as previously described in relation to the fifth aspect.

[0129] According to a fourteenth aspect, there is provided a method for manufacturing a cooling container, comprising providing a heat exchanger obtained by the method of the ninth aspect, or a heat exchanger according to the tenth aspect, forming the heat exchanger into a desired shape, and inflating the heat exchanger. The method may be performed as described above in relation to the seventh aspect.

[0130] According to a fifteenth aspect, there is provided a method of cooling milk comprising providing a cooling container comprising a heat exchanger according to the tenth aspect or a heat exchanger assembly according to the eleventh aspect, providing milk in a product space of said cooling container, allowing a coolant to flow through said heat exchanger or heat exchanger assembly, and stirring the milk by an agitator. The method may be performed as described above in relation to the eighth aspect.Brief description of the drawings

[0131] The invention will in the following be described in more detail with reference to the enclosed drawings, wherein: Figs 1a-1c schematically illustrates cooling containers comprising a heat exchanger assembly. Figs 2a-2c schematically illustrates a heat exchanger and a heat exchanger assembly. Figs 3a-3d schematically illustrates enlarged portions of a detailed view of the heat exchanger as illustrated in Figs. 2a-2c. Fig. 3a displays a main portion and an end portion of the welded baffle line, and also schematically illustrates an example of a flow path for a coolant. Fig. 3b displays a main portion and an end portion of the welded baffle line, wherein the end portion has a rounded shape, and also schematically illustrates an example of a flow path for a coolant. Fig. 3c schematically illustrates a plurality of welded spots in a continuous diamond pattern. Fig. 3d schematically illustrates a zig-zag shaped edge portion. Fig. 4 schematically illustrates a cross-sectional view of a heat exchanger. Fig. 5 schematically illustrates a system comprising a cooling container. Figs 6a-6c schematically illustrates a method for manufacturing a heat-exchanger. Detailed description

[0132] The present inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled addressee. Like reference characters refer to like elements throughout.

[0133] The present inventive concept finds use in various types of containers for cooling, such as tanks or silos for cooling of a product.

[0134] The heat exchanger may be an evaporator.

[0135] The heat exchanger may be placed within or as a wall of an inner container space 101 holding the product to be cooled.

[0136] In the following description, the inventive concept will be described with reference to a cooling container 100 in form of a silo for milk cooling, having a heat exchanger comprising a pair of plate materials 2a, 2b, an inlet 12 and an outlet 13 for a coolant.

[0137] The coolant may be CO 2 . However, any other suitable coolant may be used, such as a natural or synthetic coolant, for example propane, ammonia, or HFC-refrigerants.

[0138] A lubricant, such as an oil may be mixed with the coolant. The oil may be insoluble with the coolant. Alternatively, the oil may be at least partly soluble with the coolant. The coolant may be at least partly soluble with the oil. The oil may for example be a polyol ester (POE) oil or a polyalkylene glycol (PAG) oil.

[0139] As illustrated in figs 1a-1c, a silo 100 may comprise a heat exchanger assembly 10 comprising two heat exchangers 1a, 1b for cooling a product stored in the silo 100. The product to be cooled by the heat exchanger assembly 10 may be milk, water, beer or any other beverage or intermediate in production of a beverage. The heat exchanger assembly 10 may be positioned in a bottom part of the silo 100, so as to constitute a bottom wall of a storage space 101, i.e. a product space, within the silo 100. The product being in the vicinity of the heat exchanger assembly 10 may heat exchange with the coolant of the heat exchanger 1a, 1b. To achieve an even more effective cooling of the product, the silo 100 may, according to one embodiment, comprise equipment for agitating the product within the silo 100. For example, the silo may comprise at least one agitator. By agitating the product, a more even cooling of the product may be achieved.

[0140] The heat exchanger assembly 10 may constitute a bottom wall that is conical, in which the walls are tapering in a downwards direction. The bottom part, where a mantle of the conical shape meet, may comprise an outlet for the product, so that the product may be emptied in a convenient way from the silo 100. Further, the silo 100 may comprise an inlet (not shown) for the product. The inlet may be placed in an upper part of the silo 100.

[0141] The heat exchanger assembly 10 may be a centered conical shape, as illustrated in fig. 1b. The heat exchanger assembly 10 may be a skewed conical shape, as illustrated in fig. 1c.

[0142] The silo 100 may have a product volume of 1500-2500 liters, 2500-3500 liters, 3000-4000 liters, 4000-5000 liters, 5000-6000 liters, 6000-7000 liters, 7000-8000 liters, 9000-10 000 liters, 10 000-20 000 liters, 20 000-30 000 liters, 30000-40 000 liters, 40 000-50 000 liters, 50 000-60 000 liters, or 60 000-70 000 liters. The silo 100 may have a height of 2-3, 3-4, 4-5, 5-6, 6-7, 7-8, 8-9 or 9-10 meters. A diameter of the silo 100 may be 1-5 meters, preferably 1.5-4 or 2-3.5 meters.

[0143] As illustrated in figs. 1a-1c, the cooling container may comprise a container wall portion 102. As illustrated, the container wall portion may be cylindrical. However, other shapes and / or sizes are possible. Further, as illustrated, the container wall portion may be joined with the heat exchanger assembly 10.

[0144] Figs 1a-1c illustrate one example of a cooling container in form of a silo. However, it is understood that other shapes and / or sizes of the cooling container is possible. For example, the cooling container may be a horizontal tank, such as a horizontal milk tank.

[0145] Further, although not illustrated, the silo 100 may be provided with an outer jacket. Thus, the silo 100 may form part of an assembly comprising the silo forming an inner cooling container and a jacket forming an outer tank.

[0146] There may be a distance between the silo and the jacket of 50-150 mm, which creates a space that may be filled with insulating material.

[0147] In fig. 2a, a heat exchanger 1a is schematically illustrated. The heat exchanger 1a comprises a pair of plate materials 2a, 2b, wherein a peripheral portion of at least one of the plate materials 2b is joined to the other plate material 2a by a seal 14 such to form a sealed coolant passage space 11 between the plate materials 2a, 2b. The seal 14 may be welded.

[0148] The heat-exchanger 1a, 1b and heat exchanger assembly 10 in figs 2a-2c are illustrated as being substantially flat, wherein both surfaces of the heat exchangers 1a, 1b are substantially flat. When being manufactured, the heat exchanger 1a, 1b may be flat and un-inflated and unpressurized. The heat exchanger 1a, 1b or heat exchanger assembly 10 may at a later stage first be formed to a desired shape and mounted in a cooling container, such as a tank or silo, and then be pressurized and inflated. The heat exchanger 1a, 1b may be mounted in a supporting structure, that supports the heat exchanger 1a, 1b when being inflated so as to keep the desired shape of the heat exchanger 1a, 1b intact. In an alternative embodiment the heat exchanger 1a, 1b or heat exchanger assembly 10 may be pressurized and inflated after being manufactured, and at a later stage being mounted in a cooling container, such as a tank or silo. When the heat exchangers 1a, 1b or heat exchanger assembly 10 are pressurized and inflated, one surface may remain substantially flat and the opposite surface may be deformed. The deformed surface may present a surface having bubble shapes or pillow shapes. The substantially flat surface may be the surface of the plate material 2a, and the deformed surface may be the surface of the plate material 2b.

[0149] The heat exchanger 1a further comprises an inlet 12 for a coolant and an outlet 13 for the coolant. The coolant may be passed through the heat exchanger 1a from the inlet, to the outlet, in order to heat exchange with the surrounding of the heat exchanger 1a.

[0150] The pair of plate materials 2a, 2b are further weld together by a weld pattern 30 comprising a plurality of welded spots 31. The weld pattern may provide an even flow of the coolant through the heat exchanger 1a.

[0151] Further, a flow of coolant through the heat exchanger 1a may be guided in a serpentine pattern across the coolant passage space 11 between the plate materials 2a, 2b by welded baffle lines 32. The welded baffle lines 32 may create a channel within the passage space 11 for the flow of coolant. The heat exchanger 1a may comprise at least one or at least two welded baffle lines 32. The embodiment according to fig. 2a discloses a heat exchanger 1a having four welded baffle lines 32. According to another embodiment (not illustrated), the heat-exchanger may have three, five, six, seven or more welded baffle lines 32.

[0152] The baffle lines 32 comprises a main portion 321 extending in a first direction, and an end portion 322 extending in a second direction being different from the first direction. The main portion 321 may extend as a first straight line. The end portion 322 may connect to the main portion 321 by creating a first angle α between the main portion 321 and the end portion 322, as seen in fig. 3a. The first angle α may be about 80-90° or 90-100° or 100-110° or 110-120° or 120-130° or 130-140° or 140-150° or 150-160°. The end portion 322 may connect at its other end to the seal 14. The end portion 322 may extend as a second straight line or as a curved line. A connection point 141 at which the end portion 322 and seal 14 connects may create a second angle β between the end portion 322 and a tangent T that tangents the connection point 141, as seen in fig. 3a. The second angle β may be about 70-80° or 80-90° or 90-100° or 100-110° or 110-120°.

[0153] A distance S between the main portions 321 of two adjacent welded baffle lines 32 may be about 140-150 mm or 150-160 mm or 160-170 mm or 170-180 mm or 180-190 mm or 190-200 mm or 200-210 mm or 210-220 mm.

[0154] The heat exchanger 1a according to an embodiment of fig. 2a has a half circle-resembling shape. By half circle-resembling shape is meant a shape substantially having the shape of a half circle and having a portion deviating from the half circular shape. The deviating portion may be a cutout portion. In the embodiment of fig. 2a, the main portion 321 of the welded baffle lines 32 may extend parallel to a base of the half circle.

[0155] The plate material 2a according to fig. 2a is shaped as having a circle arc that extends from the base of a half circle in one end, until there is a circle sector having an angle of about 8-12° left until the circle arc would have reached a base line. The base extends from the end connected to the arc and about 65-75% of the distance of a full base line for a half circle. The base comprises a half circular-resembling recess for shaping an outlet of an inner container space. The edge of the plate material 2a then continues in a straight line that meet the arc. The base of the half circle of the plate material 2a may have additional recesses for fixing of at least one agitator and / or at least one temperature sensor. The plate material 2b according to fig. 2a may have essentially the same shape as the plate material 2a, differing in that the arc extends until there is a circle sector having an angle of about 14-18° left until the circle arc would have reached a base line. The base extends in the same direction as the base of the plate material 2a. The extent of the base of the plate material 2a may be larger than the extent of the base of the plate material 2b. The base of the plate material 2b then continues in a quarter circular recess continuing in a substantially straight edge line parallel with an extension of the base, said edge line extends for a distance shorter than a distance needed to reach the arc. An end of the arc and an end of the straight edge line of the recess is then connected by a substantially straight edge line. However, the heat exchangers 1a, 1b are not limited to this shape. The heat exchangers 1a, 1b may be shaped as circles, half circles, squares, rectangles or any other suitable shape.

[0156] An edge portion 20 of at least one of the plate materials 2a, 2b may have a zig-zag shape. The edge portion may have a curved periphery before being cut into a zig-zag shape. The zig-zag shape may be provided by a zig-zag pattern. The zig-zag pattern may be provided along at least a portion of the periphery of the plate material 2a, 2b, preferably along more than 50 % of the periphery, more preferably along more than 75 % or along more than 90 % of the periphery of the plate material.

[0157] In fig. 2a, the edge portion 20 extends over the circle arc, the base, and the straight parts connecting the arc and the base. In an alternative embodiment (not illustrated), only the circle arc has a zig-zag shaped edge portion 20. During welding, the plate material 2a, 2b may shrink and warp, due to the high temperature treatment. By having a zig-zag shaped edge portion 20, the plate materials 2a, 2b may be allowed to shrink without interfering with the design of the heat exchanger 1a, and the risk of warping is decreased.

[0158] Along the base of the half circular heat exchanger there may be a separate channel 15, having an inlet 151 and an outlet 152. In the channel 15, ethanol, glycol or any other coolant may be circulated so as to create a cooled outlet for the product. Thereby, product located at the outlet, which may not be sufficiently cooled by coolant flowing through the coolant passage space 11 can be cooled. When a product is loaded to the inner container space 101 of the cooling container 100, the outlet of the inner container space may be closed, for example by a closing mechanism. However, the closing mechanism of the inner container space can be located within the outlet, thereby allowing a portion of the product to be stored in the beginning of the outlet. The outlet may not be in contact with the heat exchanger 1a, 1b, instead, a separate cooling circuit may cool the product in the outlet. This cooling circuit may be connected to the inlet 151 and the outlet 152 of the channel 15, so that a coolant of said cooling circuit is cooled within the channel 15 by the cooled product.

[0159] The heat exchanger 1a may have a diameter of about 1.5-2 m or 2-2.5 m or 2.5-3 m or 3-3.5 m or 3.5-4 m or 4-4.5 m or 4.5-5 m. In one embodiment, the diameter may be 2.3 m. In another embodiment, the diameter may be 3 m. The heat exchanger 1a may have a surface area of 2-3 m 2< or 3-4 m 2< or 4-5 m 2< or 5-6 m 2< or 6-7 m 2< or 7-8 m 2< .

[0160] The description above of a heat exchanger 1a equally applies to a heat exchanger 1b comprising the same parts but being mirrored to the heat exchanger 1a.

[0161] Fig. 2b schematically illustrates a heat exchanger 1a. The description above in relation to fig. 2a equally applies to the heat exchanger of fig. 2b, except for that the end portion 322 is a curved line, having a radius of about 110 mm.

[0162] Fig. 2c schematically illustrates a heat exchanger assembly 10 comprising a heat exchanger 1a and a heat exchanger 1b. The heat exchangers 1a, 1b and the parts illustrated in fig. 2c may have the same functions and features as described above in connection to fig. 2a or fig. 2b.

[0163] The heat exchangers 1a, 1b may be welded together along the base of the respective half circle. In fig. 2c, the heat exchanger assembly 10 is illustrated flat. A flat heat exchanger assembly 10 may be used, for example in a cylindrical milk tank. The heat exchanger assembly 10 may be shaped so as to be conical, as illustrated in figs 1a-1c, and used in a silo as a bottom portion of an inner storage space of a silo for cooling milk.

[0164] Fig. 3a-d schematically illustrates enlarged portions of detailed views of a heat exchanger 1a, 1b. The main part 321 of the welded baffle line 32 may be welded along a row of welded spots 31. In fig. 3a, the main portion 321 may be substantially straight, and extending parallel to the base of a half circular heat exchanger 1a, 1b. The end portion 322 may connect to one end of the main portion 321, thereby creating a first angle α between the main portion 321 and the end portion 322. The first angle α may be about 80-90° or 90-100° or 100-110° or 110-120° or 120-130° or 130-140° or 140-150° or 150-160°. According to the embodiment of fig. 3a, the first angle α is about 130-140°.

[0165] The end portion 322 may be substantially straight. The end portion 322 may extend so as to connect to the seal 14. As may be seen in fig. 3a, the end portion 322 may extend past the seal 14, so as to intersect the seal 14. By extending past the seal 14, the welded lines provide a robust channel with minimum risk for a leakage between lines and thereby preventing creating bypass channels for the coolant.

[0166] In an alternative embodiment, the end portion 322 may be curved so as to have a radius, as illustrated in fig. 3b. All other features described in connection to fig. 3a equally applies to the heat exchanger of fig. 3b.

[0167] The seal 14 may comprise two welded lines. Thereby, the seal 14 creates a more robust welded line, if one line is failing, the heat exchanger 1a, 1b is still sealed from the outer surroundings, and the coolant is kept within the sealed coolant passage space 11.

[0168] According to the embodiment of fig. 3a, the plate material 2a is of larger dimensions than the plate material 2b. The peripheral portion of the plate material 2b is joined to the plate material 2a, thereby leaving a larger part of the plate material 2a protruding from the seal 14 than on the plate material 2b.

[0169] As seen in fig 3a-3c, the welded spots 31 may form a continuous diamond pattern. As illustrated in fig. 3c, the diamond pattern may have a first distance D 1 between the spots 31 in a first direction and a second distance D 2 in second direction, wherein the first and the second directions are perpendicular to each other. The first distance D 1 may be 15-20 mm or 20-25 mm or 25-30 mm or 30-35 mm. The second distance D 2 may be 30-35 mm or 35-40 mm or 40-45 mm or 45-50 mm or 50-55 mm or 55-60 mm. According to the embodiment of figs. 3a-3c, the first distance D 1 may be 22-26 mm and the second distance D 2 may be 40-44 mm.

[0170] The coolant may flow in between the welded spots 31. The welded spots 31 may enable a swirling flow, thereby achieving a good mixing of the coolant and an even flow of the coolant through the sealed coolant space 11. The coolant may flow in a swirling way around the welded spots 31, as seen in fig. 3a, taking different directions, but resulting in a net flow as illustrated in figs. 2a-b.

[0171] Further, at least one of the pair of plate materials 2a, 2b may have a zig-zag shaped edge portion 20. As seen in fig. 3a, the plate material 2b has a zig-zag shaped edge portion 20. The zig-zag shaped edge portion 20 of the plate material 2b is positioned on the plate material 2a. The plate materials 2a, 2b as illustrated in fig. 3a are joined together by a welded seal 14.

[0172] As illustrated in fig. 3d, the zig-zag shape may be a pattern comprising a plurality of triangles having a height H. The height may be 3-15 mm, preferably 5-13 mm or 7-11 mm. The triangles of the zig-zag shape pattern may have an internal angle δ of 30-40° or 40-50° or 50-60° or 60-70° or 70-80° or 80-90° or 90-100° or 100-110° or 110-120°.

[0173] Fig. 4 schematically illustrates a cross-sectional view of a heat exchanger 1a, 1b, after the heat exchanger 1a, 1b has been pressurized and inflated. The heat exchanger 1a, 1b may be a single-embossed pillow plate. The description of the heat exchanger 1a, 1b above, equally applies to the heat exchanger 1a, 1b in fig. 4. The pair of plate materials 2a, 2b may be of different thickness. The plate material 2a may be thicker than the plate material 2b.

[0174] The welded spots 31 creates spots or areas where the plate materials 2a, 2b are joined together, so that when pressurizing and inflating the heat exchanger 1a, 1b, the inflated areas create the pillow plate structure. When pressurizing and inflating the heat exchanger 1a, 1b, the sealed coolant passage space 11 may be inflated so that a coolant may pass through the space 11.

[0175] Fig. 5 schematically illustrates a system comprising a heat exchanger. The system may comprise a cooling container 100, a compressor 200, a gas cooler 300 and an expansion valve 400. The coolant may flow through the system. In the cooling container, the coolant may pass through a heat exchanger 1a, 1b or a heat exchanger assembly 10, as described above in relation to figs. 1-4. The coolant heat exchange to a product stored in the cooling container 100, so that the coolant cools the product. Thereby, the coolant has a higher temperature when leaving the cooling container 100 than before entering the cooling container 100. The coolant may also have transformed from one phase to another, for example from liquid phase to vapor phase. The coolant may then flow to the compressor 200, which may compress the coolant so that pressure is raised. The temperature may be raised when compressing the coolant. Further, the coolant flows through the gas cooler 300, in which the temperature of the coolant is lowered, while the pressure is maintained. The gas cooler 300 may heat exchange the coolant with ambient air, surrounding the gas cooler 300. The coolant may change phase after treatment in the gas cooler 300, for example, the coolant may transform from vapor phase to liquid phase. The coolant may flow through the expansion valve 400. The expansion valve 400 restricts the flow of coolant to the cooling container 100, thereby may the pressure of the coolant be lowered before the coolant reaches the cooling container 100.

[0176] The system may be an inverter-driven system, so as to be a frequency-driven system. Thus, the system may be configured such to control and adjust a flow rate, or speed, of the coolant in the system.

[0177] The system may further comprise a controller (not illustrated) for controlling the flow rate of coolant within the system. The system may control the compressor 200 so that the flow of coolant may be higher or lower, thereby adjusting the cooling effect of the heat exchanger assembly 10.

[0178] The cooling container 100 may comprise a heat exchanger assembly 10 having a heat exchanger 1a and a heat exchanger 1b. The compressor 200, the gas cooler 300 and the expansion valve 400 may then supply coolant to both heat exchangers 1a, 1b, wherein the heat exchangers 1a, 1b are coupled in parallel. Alternatively, each heat exchanger 1a, 1b may be coupled to its own circuit comprising a compressor 200, a gas cooler 300 and an expansion valve 400.

[0179] Figs. 6a-6c schematically illustrates a method for manufacturing a heat-exchanger. The method may be used to produce a heat exchanger as described above in relation to figs. 2-3. The method may comprise providing S1 two plate materials, cutting S2 at least one edge portion of one of the two plate materials into a zig-zag shape, joining S3 a peripheral portion of at least one of the plate materials to the other plate material by a seal, and welding S4 the two plate materials together by a weld pattern, including welding a plurality of spots. The seal may be provided by welding. The seal may be formed by seam welding, such as laser seam welding. The weld pattern may be provided by laser welding. The spots may be formed by spot welding, such as laser spot welding. The method may comprise, after the cutting step S2, aligning the plate materials so that a surface of each plate material is facing each other. The step S4 may further comprise welding at least one baffle line. The at least one baffle line may be provided by laser welding.

[0180] The step S3 of joining a peripheral portion of at least one of the plate materials to the other plate material by a seal, and the step of welding S4 the two plate materials together by a weld pattern may be performed separately or simultaneously. As one example, the step of welding the two plate materials together by a weld pattern may be performed after the seal is provided, see fig. 6a. Alternatively, the seal may be provided after the weld pattern, see fig. 6b. Alternatively, the seal and weld pattern may be provided simultaneously, see fig. 6c. In step S4, the spots and at least one baffle line may be provided simultaneously or as sub-steps. Thus, the spots may be provided before said at least one baffle line. Alternatively, the at least one baffle line may be provided before said spots. The weld pattern may be provided as described above in relation to figs. 2-3.

[0181] Further, the heat exchanger as described above in relation to figs. 2-3 or as obtained by the method as described in relation to figs. 6a-6c may be used to produce a cooling container, for example a cooling container as described in relation to fig. 1a-1c and fig. 5. A method for manufacturing a cooling container can comprising providing said heat exchanger, forming the heat exchanger into a desired shape, and inflating the heat exchanger. After inflation, the heat exchanger may present the form as illustrated in fig. 4. The desired shape of the heat exchanger may for example be conical or cylindrical. The method may comprise joining the heat exchanger to a cooling container portion for forming the cooling container. For example, the method may comprise joining the heat exchanger to a container wall portion. The joining may be performed by welding. Joining the heat exchanger to another cooling container portion may be performed before the inflation of the heat exchanger. Joining the heat exchanger to another cooling container portion may be performed after the heat exchanger has been formed into the desired shape. The container wall portion may form a support structure for the heat exchanger when being inflated. The support structure enables inflation of the heat exchanger, such to form the pillow structure of the heat exchanger, while also ensuring that the heat exchanger maintain the desired shape. Alternatively, a separate support structure, different from the container wall portion, may be provided. The support structure may have essentially the same shape as said desired shape of the heat exchanger. Thus, the heat exchanger may be placed within the support structure before being inflated.

[0182] Further, the step of forming the heat exchanger may comprise joining the heat exchanger to another heat exchanger by welding, such to form a heat exchanger assembly, for example as described above in relation to fig. 1a-1c and fig. 2c. The step of forming the heat exchanger may comprise forming the heat exchanger or heat exchanger assembly into a conical-shaped end portion of the product space of the cooling container, as illustrated in figs 1b-1c. The forming may comprise bending the heat exchanger or heat exchanger assembly, i.e. the pair of plate materials that are welded together may be processed, such as in a bending process, into the desired shape. The method may further comprise joining the cooling container with a jacket (not illustrated).

[0183] The heat exchanger, heat exchanger assembly, cooling container and / or system as described above in relation to figs. 1-5 may be used in a method of cooling a liquid, such as for example milk. Thus, a method of cooling milk may comprise providing a cooling container comprising a heat exchanger as disclosed above or a heat exchanger assembly as disclosed above, providing the liquid, such as milk, in a product space of said cooling container, allowing a coolant to flow through said heat exchanger or heat exchanger assembly, and stirring the liquid by an agitator.

Examples

Embodiment Construction

[0132]The present inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled addressee. Like reference characters refer to like elements throughout.

[0133]The present inventive concept finds use in various types of containers for cooling, such as tanks or silos for cooling of a product.

[0134]The heat exchanger may be an evaporator.

[0135]The heat exchanger may be placed within or as a wall of an inner container space 101 holding the product to be cooled.

[0136]In the following description, the inventive concept will be described with reference to a cooling container 100 in form of a silo for milk cool...

Claims

1. A heat exchanger (1a, 1b) for a cooling container, such as a tank for milk cooling, the heat exchanger (1a, 1b) comprising: a pair of plate materials (2a, 2b), an inlet (12) for a coolant, and an outlet (13) for the coolant; wherein a peripheral portion of at least one of the plate materials is joined to the other plate material by a seal (14) such to form a sealed coolant passage space (11) between the plate materials (2a, 2b), and wherein the pair of plate materials (2a, 2b) are welded together by a weld pattern (30), wherein the weld pattern comprises a plurality of welded spots (31), wherein the weld pattern comprises at least one welded baffle line (32) for directing a flow of coolant from the inlet (12) to the outlet (13) when in use, wherein the welded baffle line (32) comprises a main portion (321) extending in a first direction, and an end portion (322) extending in a second direction being different from the first direction.

2. The heat exchanger according to claim 1, wherein the weld pattern comprises two welded baffle lines (32) for directing a flow of coolant from the inlet (12) to the outlet (13) when in use, wherein the two welded baffle lines (32) each comprises a main portion (321) extending in a first direction, and an end portion (322) extending in a second direction being different from the first direction.

3. The heat exchanger according to claim 1 or 2, comprising a first welded baffle line and an adjacent second welded baffle line, wherein the first welded baffle line and the second welded baffle line form a channel for passing a flow of coolant between a first turning zone and a second turning zone, wherein each one of the first and second welded baffle lines comprises a main portion (321) extending in a first direction, and an end portion (322) extending in a second direction being different from the first direction.

4. The heat exchanger according to any one of the preceding claims, wherein a first angle (α) between the main portion (321) and the end portion (322) is 80-160°, preferably 90-150° or 110-140°.

5. The heat exchanger according to any one of the preceding claims, wherein the main portion (321) extends as a first straight line, and wherein the end portion (322) extends as a second straight line or as a curved line.

6. The heat exchanger according to any one of the preceding claims, wherein said end portion (322) is connected to said seal (14), or the end portion (322) intersects said seal (14).

7. The heat exchanger according to claim 6, wherein a second angle (β) between the end portion (322) and a tangent (T) that tangents a connection point (141) at which the end portion (322) and seal (14) connects, is 70-120°, preferably 75-110° or 90-100°.

8. The heat exchanger according to any one of the preceding claims, wherein the weld pattern (30) comprises at least two welded baffle lines (32), wherein a distance (S) between the main portions (321) of two adjacent welded baffle lines (32) is 140-220 mm, or 150-215 mm, preferably 170-210 mm or 180-200 mm.

9. The heat exchanger according to any one of the preceding claims, wherein the plurality of welded spots (31) form a continuous diamond pattern having a first distance (D1) between the spots (31) in a first direction and a second distance (D2) in second direction, wherein the first and the second directions are perpendicular to each other, wherein the first distance (D1) is 15-35 mm, preferably 20-30 mm, and wherein the second distance (D2) is 30-60 mm, preferably 40-55 mm.

10. The heat exchanger according to any one of the preceding claims, wherein at least one of the pair of plate materials (2a, 2b) has a zig-zag shaped edge portion (20).

11. The heat exchanger according to any one of the preceding claims, wherein a first side of the heat exchanger presents a substantially flat surface, and an opposite second side of the heat exchanger presents a substantially flat surface.

12. A heat exchanger assembly (10) comprising two heat exchangers (1a, 1b) according to any one of claims 1-11, wherein the two heat exchangers are welded together.

13. A cooling container (100) comprising a heat exchanger (1a, 1b) according to any one of claims 1-11 or a heat exchanger assembly (10) according to claim 12.

14. A system comprising a cooling container (100) according to claim 13, and a coolant.

15. The system according to claim 14, wherein the system is an inverter-driven system.

16. A method for manufacturing a heat exchanger comprising: providing two plate materials (2a, 2b), joining a peripheral portion of at least one of the plate materials (2a, 2b) to the other plate material by a seal, and welding the two plate materials (2a, 2b) together by a weld pattern, including: welding a plurality of spots (31), and welding at least one baffle line (32), wherein the at least one baffle line (32) is welded such to comprise a main portion (321) extending in a first direction, and an end portion (322) extending in a second direction being different from the first direction.

17. A method for manufacturing a cooling container (100), comprising: providing a heat exchanger (1a, 1b) obtained by the method according to claim 16, or a heat exchanger (1a, 1b) according to claim 11, forming the heat exchanger (1a, 1b) into a desired shape, and inflating the heat exchanger (1a, 1b).

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