Heat exchange unit

Abstract

To provide a heat exchange device that minimizes the loss of thermal energy from the heat-exchanged fluid, such as high-temperature wastewater, while also being easy to maintain. [Solution] In a heat exchange apparatus that performs heat exchange between a heat transfer medium and a heat exchange fluid by allowing the heat exchange fluid to flow in a thin film down the outer surface of a heat transfer medium flow tube 4, the support member 9 that supports the heat transfer medium flow tube has at least a right cylindrical portion, and the heat transfer medium flow tube is formed into a spiral shape to conform to the outer shape of the support member by rotating it around a vertical axis so that the heat transfer medium inlet 7 is at the lowest end and the outlet 8 is at the uppermost end, and is supported by the support member, and a cover body 10 is provided on the outside of the heat transfer medium flow tube, and the cover body has at least a side portion, the side portion being a vertical side portion provided parallel to the right cylindrical portion of the support member, and its upper and lower bottom portions are open, and the space between the support member and the cover body is a guide flow passage C for the heat exchange fluid to flow down the outer surface of the heat transfer medium flow tube.

Description

[Technical Field]

[0001] The present invention relates to a heat exchange unit, and more particularly to a falling liquid film heat exchanger that performs heat exchange by causing a heat medium flowing inside heat transfer tubes and a fluid to be heat-exchanged to flow down in a thin film form on the outer surfaces of the heat transfer tubes. [Background Art]

[0002] The government has set a target of reducing carbon dioxide (CO₂) emissions from energy sources, which account for the majority of greenhouse gases, to zero by 2050, increasing the need for energy conservation. When talking about energy conservation, electric energy often comes to mind first. On the other hand, although thermal energy is consumed in many processes such as production activities at factories of various enterprises, as an approach for energy conservation measures, it has not become as widely recognized and prevalent as electric energy.

[0003] As a well-known energy conservation measure from the perspective of thermal energy, there are large-scale initiatives by local governments and other organizations to effectively utilize the large amount of heat (waste heat) generated in waste incineration facilities as power generation, steam, and hot water. On the other hand, even without such large-scale waste heat, thermal energy is consumed and discharged as waste heat in many scenarios during production processes. However, most of such small and medium-scale waste heat is not recognized as reusable thermal energy and is often directly discarded as waste heat.

[0004] For example, examples of waste heat include cleaning equipment used in food factories and kitchens, and medium-high temperature wastewater discharged after heating food and other materials. If such waste heat can be recovered and reused as thermal energy, the fuel used to generate thermal energy can be reduced. This not only reduces costs for enterprises, but also cuts CO₂ emissions, killing two birds with one stone.

[0005] Reducing environmental impact is a societal demand, regardless of scale, and is unavoidable for businesses. Patent documents 1 and 2 are highly significant inventions that address this need, opening the way for even small-scale waste heat to be recovered and reused as thermal energy.

[0006] Specifically, the heat exchange unit is housed in a case, and a storage tank with numerous drip holes on its bottom is located on top of the case. The fluid to be heat exchanged is dripped from these drip holes towards the heat transfer medium flow pipe of the heat exchange unit, and heat exchange takes place between the heat transfer medium in the heat transfer medium flow pipe and the fluid to be heat exchanged. The heat exchange unit is detachably mounted from the case. This configuration is common to both Patent Documents 1 and 2.

[0007] Furthermore, if the heat exchange fluid is, for example, hot wastewater used for cleaning, that wastewater is often dirty or contains impurities. Therefore, Patent Documents 1 and 2 also emphasize ease of maintenance, such as being able to remove the heat exchange unit from its case and clean the heat transfer medium flow pipes.

[0008] Furthermore, in Patent Documents 1 and 2, in order to efficiently drip the heat exchange fluid onto a heat transfer medium flow pipe that is formed in a long, narrow oval shape or a loop shape wound in a circular shape when viewed from above, a storage tank is installed at the top of the heat exchange unit, and the heat exchange fluid is temporarily stored there. The bottom surface of the storage tank is provided with numerous small-diameter dripping holes that match the shape of the heat transfer medium flow pipe, and the heat exchange fluid is evenly dripped onto the heat transfer medium flow pipe from there.

[0009] However, Patent Document 1 has drawbacks such as the dripping holes becoming clogged or the large amount of hot water being discharged overflowing from the storage tank. In such cases, the hot water not only reduces the heat exchange efficiency as a heat-exchanged fluid that does not undergo heat exchange, but it also overflows from the case, soiling the floor of factories and other facilities.

[0010] Therefore, Patent Document 2 provides an overflow pipe in the storage tank, and further provides a guide member made of a circular flat plate between the storage tank and the heat transfer medium flow pipe, so that the heat-exchanged fluid that flows out from the overflow pipe becomes a dripping channel for the heat-exchanged fluid that drips from the dripping hole in the storage tank into the heat transfer medium flow pipe.

[0011] However, Patent Document 2 does not completely solve the problem of the drip holes becoming clogged. When the drip holes become clogged, the heat exchange fluid can only come into contact with the heat transfer medium flow pipe after passing through the overflow pipe and guide member, and during this time, the temperature of the heat exchange fluid decreases, resulting in poor thermal efficiency. In addition, the structure becomes complex due to the inclusion of the overflow pipe and guide member, making maintenance, including cleaning them, time-consuming. [Patent Document 1] Japanese Patent Publication No. 2021-042868 [Patent Document 2] Patent No. 7138384 [Overview of the project] [Problems that the invention aims to solve]

[0012] In view of the aforementioned problems, this invention aims to minimize the loss of thermal energy from the heat-exchanged fluid, such as wastewater discharged from a cleaning device, and to provide a heat exchange device that is easy to maintain. [Means for solving the problem]

[0013] The heat exchange device according to the present invention is a heat exchange device that performs heat exchange between a heat transfer medium and a heat transfer fluid by allowing a heat exchange fluid to flow in a thin film down the outer surface of a heat transfer medium flow tube through which a heat transfer medium flows internally. The support member has at least a right cylindrical portion or a right-angled prism portion, and the heat transfer medium flow tube is formed into a spiral shape to conform to the outer shape of the support member by rotating it around a vertical axis such that the side connected to the inlet of the heat transfer medium is at the lowest end and the side connected to the outlet is at the uppermost end, and is supported by the support member. A cover body is provided on the outside of the heat transfer medium flow tube, and the cover body has at least a side portion, the side portion being a vertical side portion provided parallel to the right cylindrical portion or right-angled prism portion of the support member, and its upper and lower bottom portions are open, and the space between the support member and the cover body is a guide flow passage for the heat exchange fluid to flow down the outer surface of the heat transfer medium flow tube.

[0014] Because there are no physical barriers between the heat-exchange fluid and the heat transfer medium flow tube, the heat-exchange fluid can directly contact the heat transfer medium flow tube while minimizing the loss of thermal energy. Furthermore, the cover prevents the heat-exchange fluid from splashing unnecessarily, allowing it to adhere closely to the heat transfer medium flow tube and flow down in a thin film, resulting in efficient and waste-free heat exchange. In addition, since the heat transfer medium flow tube, support member, and cover are all independent parts, they can be easily removed and cleaned.

[0015] Furthermore, the support member of the heat exchange device of this invention is characterized in that the upper part of the right cylindrical portion or the right-angled cylindrical portion has a conical portion or a polygonal thrust portion.

[0016] This prevents the heat exchange fluid, which flows in large quantities and hits the support members, from scattering unnecessarily, and instead guides it efficiently into the heat transfer medium flow pipe.

[0017] Furthermore, the cover body of the heat exchange device of the present invention is characterized in that the upper part of the vertical side surface has an inverted conical side surface or an inverted polygonal pyramidal side surface that extends in a direction away from the conical or polygonal thrust portion of the support member.

[0018] This allows for the guidance of a large amount of heat-exchangeable fluid into the heat transfer medium flow tube, minimizing spillage even when a large amount of heat-exchangeable fluid flows down from a cooking pot or similar container.

[0019] Furthermore, the heat exchange device of this invention is characterized in that at least one notch is provided at the lower end of the vertical side surface of the cover body.

[0020] This allows the heat-exchanged fluid, which has finished exchanging heat with the heat transfer medium flow pipe, to flow out through the notch. For example, the heat exchange device of this invention can be directly mounted in a drain pit located directly beneath a cooking pot in a kitchen to receive high-temperature wastewater flowing out of the cooking pot.

[0021] Furthermore, the heat transfer medium flow pipe of the heat exchange device of this invention is characterized by having a spiral-shaped portion or a helical-shaped portion around a vertical axis that matches the shape of the upper part of the support member. This allows the flow of the heat transfer medium flow pipe to be made longer, and the heat exchange fluid to be heated can come into contact with the heat transfer medium flow pipe at a position closer to the flow position of the heat exchange fluid.

[0022] Furthermore, the heat transfer medium flow pipe, cover body, and support member of the heat exchange device of this invention are housed in a housing box, and this housing box is provided with an outlet for discharging the heat exchange fluid that overflows from the guide flow passage and the heat exchange fluid that flows out from the cutouts in the cover body. By providing a housing box, this device can be safely adopted even in environments where the heat exchange fluid does not flow directly onto the floor. [Brief explanation of the drawing]

[0023] [Figure 1] This figure shows a schematic diagram of a heat exchange system in a kitchen, which is one example of a heat exchange device according to the present invention. [Figure 2]These are (a) a cross-sectional view, (b) a plan view, (c) an enlarged view of part A, and (d) a perspective view of a cover body, schematically showing one embodiment of the heat exchange device according to the present invention. [Figure 3] These are views showing another shape of the heat exchange device according to the present invention, which are (a) a circular cylinder, (b) a perspective view of the cover body of (a), (c) an ellipse, and (d) a polygonal prism. [Figure 4] These are views showing a state where the heat exchange device according to the present invention is accommodated in a storage box, which are (a) a perspective view and (b) a front cross-sectional view. [Mode for Carrying Out the Invention]

[0024] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the drawings, the same or corresponding portions are denoted by the same reference numerals. Note that the term "right circular cylinder" is used to mean not only a circular shape in plan view, but also includes an elliptical shape in plan view; and the term "right prism" is used to mean including squares and rectangles in plan view, and for example also includes hexagons in plan view.

[0025] Reference numeral 1 in Fig. 1 denotes a heat exchange device according to a first embodiment of the present invention, which is a diagram schematically showing a heat exchange system in a kitchen. The heat exchange device is installed in a drainage pit 3 provided directly below a large cooking pot 2 used in kitchens such as catering centers. When a fluid to be heat-exchanged, which is high-medium temperature wastewater discharged from the cooking pot 2, drips under its own weight onto a heat transfer medium flow pipe 4 of the heat exchange device 1, heat exchange is performed between the fluid to be heat-exchanged and the heat transfer medium flowing inside the heat transfer medium flow pipe.

[0026] Water supply pipes 5 and 6 are connected to an inlet 7 and an outlet 8 of the heat transfer medium flow pipe 4, respectively. This is a mechanism in which the heat transfer medium flowing inside the heat transfer medium flow pipe 4 is warmed and supplied to a hot water tank or the like such as an air conditioning boiler.

[0027] Figure 2(a) shows a schematic cross-sectional view of the heat exchanger 1. The heat transfer medium flow pipe 4 is formed into a spiral shape that is twisted around a vertical axis, following the outer shape of the right cylindrical support member 9. The upper bottom surface 9a of the support member is closed, and the heat transfer medium flow pipe 4 is removably supported by the support member 9. In order to make the flow between the heat-exchanged fluid and the heat transfer medium close to counterflow, the heat transfer medium flow pipe 4 connected to the inlet 7 connected to the water supply pipe 5 is positioned on the lowest end of the support member 9, and the outlet 8 is positioned on the uppermost end of the support member 9.

[0028] The support member 9 may support the heat transfer medium flow pipe 4 in a manner such that the uppermost pipe 4b on the outlet 8 side of the heat transfer medium flow pipe 4 rests on the upper bottom surface 9a of the support member 9, or a flange portion (not shown) may be provided on the support member 9, and the lowermost pipe 4a on the inlet 7 side of the heat transfer medium flow pipe 4 may be placed on or engaged with it. Alternatively, the heat transfer medium flow pipe 4 may be placed on the upper bottom surface 9a of the support member 9 in a spiral shape.

[0029] The pipe 4a on the inlet 7 side and the pipe 4b on the outlet 8 side are molded so that the inlet 7 and outlet 8 are at the same height, and are connected to the water supply pipes 5 and 6. A cover body 10 is placed on the outer circumference of the heat transfer medium flow pipe 4. The cover body 10 has a vertical side portion 10a that is parallel to the support member 9, and is cylindrical in shape with open top and bottom surfaces.

[0030] As shown in Figures 2(b) and 2(c), the heat-exchange fluid strikes the upper bottom surface 9a of the support member 9 and is guided to the side surface 9b. The heat-exchange fluid flows down in a thin film in the gap between the support member 9 and the side surface 9b and the outer surface of the heat transfer medium flow pipe 4, releasing heat of vaporization from the liquid film surface to the outside air, and performing heat exchange with the heat transfer medium inside the heat transfer medium flow pipe 4.

[0031] The cover body 10 plays a role in controlling the flow of the heat-exchanged fluid so that it flows evenly down the outer surface of the heat transfer medium flow pipe 4, and the space between the support member 9 and the cover body 10 serves as a guide passage C through which the heat-exchanged fluid flows.

[0032] The heat transfer medium flow tube 4 is made of a material with high thermal conductivity, specifically copper or aluminum. On the other hand, the support member 9 and cover body 10 are made of a material with lower thermal conductivity than the material used in the heat transfer medium flow tube 4, such as stainless steel. This is to concentrate the thermal energy of the heat-exchange fluid in the heat transfer medium flow tube 4. Furthermore, using stainless steel for the support member 9 and cover body 10 makes cleaning and maintenance easier because stainless steel is less prone to corrosion.

[0033] As shown in Figure 2(b), there may be a small gap S between the support member 9 and the heat transfer medium flow pipe 4. The heat-exchange fluid passes through this gap S, forming a liquid film over the entire outer surface of the heat transfer medium flow pipe 4 as it flows down through the guide passage 11 between the support member 9 and the cover body 10. Since the support member 9 and the cover body 10 are made of stainless steel, which has high heat retention properties, the heat-exchange fluid can come into contact with the heat transfer medium flow pipe 4 without losing the high temperature and thermal energy it had when it was discharged from the cooking pot 2.

[0034] The lower end of the cover body 10 is provided with one or more notches 10b, and the heat-exchanged fluid that flows down the guide channel 11 will flow out into the drain pit via these notches 10b.

[0035] The support member 12 of the heat exchanger 11 shown in Figure 3(a) has a conical portion 12b at the top of the right cylindrical portion 12a. This reduces splashing when the heat exchange fluid collides with the support member 12, and guides it more smoothly into the heat transfer medium flow pipe 13.

[0036] Furthermore, the heat transfer medium flow pipe 13 has a spiral shape that extends not only around the right cylindrical portion 12a of the support member 12, but also around the conical portion 12b, allowing the heat transfer medium to flow through the heat transfer medium flow pipe 13 for a longer period of time, and also allowing it to receive the thermal energy of the heat-exchanged fluid closer to the outlet from the cooking pot 2.

[0037] Furthermore, the side surface of the cover body 14 has a vertical side surface 14a parallel to the right cylindrical portion 12a of the support member 12, and an inverted conical side surface 14b that extends away from the conical portion 12b of the support member 12, and these side surfaces are open in the vertical direction. The space between the right cylindrical portion 12a of the support member 12 and the vertical side surface 14a of the cover body 14 serves as a guide flow passage C through which the heat exchange fluid flows.

[0038] Furthermore, the inverted conical side portion 14b allows the heat-exchanged fluid flowing out of the cooking pot 2 in large quantities to be guided into the guide flow passage C without spilling as much as possible.

[0039] Furthermore, in order to maintain the heat transfer medium inlet 17 and outlet 18 at the same height, the heat transfer medium flow pipe 13 on the inlet 17 side runs upward from the lower end of the spiral shape within the guide flow passage C. The cross-sectional path of the guide flow passage C, which is composed of the vertical side portion 14a of the cover body 14 and the right cylindrical portion 12a of the support member 12, is large enough to accommodate at least twice the diameter of the heat transfer medium flow pipe 13.

[0040] The heat exchanger 21 shown in Figure 3(b) is the same as that in Figure 3(a), except that the shape of the support member 22 is elliptical in plan view and has a right cylindrical section and a conical section at its upper part, the heat transfer medium flow tube 23 is molded into a spiral shape to match its shape, and the cover body 24 also has a vertical side section and an inverted conical side section that match its shape.

[0041] The heat exchanger 31 shown in Figure 3(c) is the same as that in Figure 3(a), except that the shape of the support member 32 is rectangular in plan view, and has a right-angled prism section and a polygonal pyramidal section corresponding to the right circular column section and cone section in Figure 3(a), the heat transfer medium flow tube 33 is molded into a spiral shape to match the shape, and the cover body 34 also has a vertical side section and an inverted polygonal pyramidal side section to match the shape. Here, a right-angled prism is a concept that includes squares, rectangular prisms, and polygons in plan view.

[0042] Figure 4 shows an embodiment in which the heat exchanger is installed on the floor surface instead of in the drain pit 3. For example, the heat exchanger 11 that receives the heat-exchange fluid discharged from the drain port 40 of the noodle-making machine is housed in a box-shaped housing 41. The housing 41 is provided with an outlet 42 for the heat-exchange fluid.

[0043] The shape of the containment box should be appropriately sized to match the shapes of the heat exchangers 1, 21, and 31, and the containment box prevents the heat-exchanged fluid from being directly discharged onto the floor.

[0044] The heat exchange device according to this invention comprises at least a heat transfer medium flow pipe, a support member, and a cover body, each of which can be installed in a removable manner, thus offering a high degree of flexibility in installation location. Furthermore, because it is removable, it is easy to clean and maintenance is extremely simple. [Explanation of Symbols]

[0045] 1, 11, 21, 31 Heat exchange equipment 4, 13, 23, 33 Heat transfer medium flow tubes 9, 12, 22, 32 Support members 10, 14, 24, 34 Cover bodies

Claims

1. In a heat exchange apparatus that performs heat exchange between a heat transfer medium and a heat exchange fluid by allowing a heat exchange fluid to flow in a thin film down the outer surface of a heat transfer medium flow tube through which the heat transfer medium flows, The support member has at least a right-circular column portion or a right-angled column portion, The heat transfer medium flow tube is formed into a spiral shape that conforms to the outer shape of the support member by rotating it around a vertical axis, such that the side connected to the heat transfer medium inlet is at the lowest end and the side connected to the outlet is at the uppermost end, and is detachably supported by the support member. A cover body is provided on the outside of the heat transfer medium flow pipe. The cover body has at least a side portion, the side portion being a vertical side portion provided parallel to the right cylindrical portion or the right-angled cylindrical portion of the support member, and the upper and lower bottom portions of the vertical side portion are open. A heat exchange apparatus characterized in that the space between the support member and the cover body serves as a guide passage for the heat exchange fluid to flow down the outer surface of the heat transfer medium flow pipe.

2. The heat exchange device according to claim 1, characterized in that the upper part of the right cylindrical portion or the right-angled cylindrical portion of the support member has a conical portion or a polygonal thrust portion.

3. The heat exchange device according to claim 2, characterized in that the upper part of the cover body has an inverted conical side portion or an inverted polygonal pyramidal side portion that extends in a direction away from the conical portion or the polygonal thrust portion of the support member.

4. The heat exchange device according to claim 3, characterized in that at least one notch is provided at the lower end of the vertical side surface portion of the cover body.

5. The heat exchange apparatus according to claim 2, characterized in that the heat transfer medium flow tube is molded into a spiral or helical shape around a vertical axis to match the shape of the upper part of the support member, and is supported by the support member.

6. The heat exchange apparatus according to claim 1, wherein the heat transfer medium flow pipe, the cover body, and the support member are housed in a housing box, and the housing box is provided with an outlet for discharging the heat exchange fluid overflowing from the guide flow passage and the heat exchange fluid flowing out from the notch in the cover body.

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