Falling film evaporator

Abstract

The utility model discloses a falling film evaporator. The falling film evaporator comprises a shell, a heat exchange pipe, a main spraying pipeline, a branch spraying pipeline, a circulating pipeline and a circulating pump, wherein the heat exchange pipe is coiled in the shell; a refrigerant flows into the branch spraying pipeline from the spraying pipeline and is sprayed to the shell; one end of the circulating pipeline communicates with the bottom of the shell, the other end of the circulating pipeline communicates with the branch spraying pipeline away from the main spraying pipeline, and the circulating pump is arranged on the circulating pipeline and used for conveying the cooling liquid in the shell to the branch spraying pipeline. The circulating pump and the circulating pipeline are arranged in the falling film evaporator, and the circulating pipeline is communicated with the branch spraying pipeline far away from the main spraying pipeline, so that the flow of the branch spraying pipeline far away from the area of the main spraying pipeline can be increased; the situation that spraying of the heat exchange pipes in the branch spraying pipeline areas far away from the main spraying pipeline area is not in place can be avoided, heat exchange uniformity can be improved, and the heat exchange efficiency can be greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of refrigeration, and in particular to a falling film evaporator. Background Technology

[0002] An evaporator is an apparatus that converts a liquid substance into a gaseous state. Evaporators are widely used in industry, with those applied to refrigeration systems being one type. Evaporators typically include dry evaporators, flooded evaporators, and falling film evaporators.

[0003] In a dry-type evaporator, the refrigerant flows inside the heat exchange tubes, while chilled water runs outside the high-efficiency heat exchange tubes. This type of heat exchanger has relatively poor heat exchange efficiency, with a heat transfer coefficient only about twice that of a bare tube heat exchanger. However, its advantages include oil return and controlled expansion, and the refrigerant charge is approximately 1 / 2 to 1 / 3 that of a flooded unit. Due to the lower wetting degree of the refrigerant inside the tubes, the heat transfer coefficient is relatively low. The larger boiling temperature difference in a dry-type evaporator can lead to larger water temperature fluctuations.

[0004] In a flooded evaporator, chilled water flows through the heat exchange tubes, which are completely submerged by refrigerant. The refrigerant absorbs heat and evaporates outside the tubes. The tube surface has numerous pinholes, and the inner surface features spiral protrusions to enhance heat transfer on the chilled water side. This highly efficient heat transfer tube design, which simultaneously enhances boiling outside the tubes and heat transfer inside, results in a high heat transfer coefficient. However, it requires a relatively large refrigerant charge. For oil-soluble refrigerants, the oil may be difficult to remove, potentially causing system problems. The static liquid level can affect the evaporation temperature, potentially leading to a higher evaporation temperature.

[0005] Falling film evaporators, also known as spray evaporators, are similar to flooded evaporators, but they also differ in some aspects. In this type of evaporator, the refrigerant is sprayed from the top of the heat exchanger onto the heat exchange tubes, forming only a thin film of refrigerant liquid on the tubes. This reduces the static liquid pressure during boiling and evaporation, thereby improving heat exchange efficiency by approximately 5% compared to flooded evaporators.

[0006] Currently, falling film evaporators are prone to scaling during use, which affects heat transfer efficiency. Inadequate spraying from the spray pipes of falling film evaporators can also significantly impact heat transfer efficiency. Utility Model Content

[0007] The technical problem to be solved by this utility model is to overcome the above-mentioned defects in the existing falling film evaporator, where the spray pipe may not spray in place, which greatly affects the heat transfer efficiency, and to provide a falling film evaporator.

[0008] The present invention solves the above-mentioned technical problems through the following technical solution:

[0009] A falling film evaporator includes: a shell, heat exchange tubes, a main spray pipe, branch spray pipes, a circulation pipe, and a circulation pump. The heat exchange tubes are coiled inside the shell. Multiple branch spray pipes are spaced apart, through which refrigerant flows from the main spray pipe into the branch spray pipes and is sprayed onto the shell. One end of the circulation pipe is connected to the bottom of the shell, and the other end is connected to a branch spray pipe located away from the main spray pipe. The circulation pump is located in the circulation pipe and is used to transport coolant from the shell to the branch spray pipes.

[0010] In this solution, by adopting the above structure, a circulating pump and circulating pipe are installed in the falling film evaporator, and the circulating pipe is connected to the branch spray pipes that are far away from the main spray pipe. This can increase the flow rate of the branch spray pipes in the area far from the main spray pipe, avoid incomplete spraying of the heat exchange tubes in the branch spray pipe area far from the main spray pipe, improve heat exchange uniformity, and greatly improve heat exchange efficiency. This enables the compressor unit to achieve the required cooling capacity and improves the overall performance of the compressor unit.

[0011] Optionally, the plurality of branch spray pipes are arranged symmetrically relative to the main spray pipe; the branch spray pipes on both sides away from the main spray pipe are all connected to the circulation pipe.

[0012] Optionally, the falling film evaporator includes two sets of circulation pipes and circulation pumps, which are symmetrically arranged relative to the main spray pipe.

[0013] Optionally, the branch spray pipe is located above the housing, and refrigerant is sprayed into the housing from top to bottom.

[0014] Optionally, the falling film evaporator includes four branch spray pipes, with two branch spray pipes on each side of the main spray pipe, and the circulation pipe is connected to the two branch spray pipes that are away from the main spray pipe.

[0015] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of this utility model.

[0016] The positive and progressive effects of this utility model are as follows:

[0017] This invention improves the flow rate of the branch spray pipes in the area away from the main spray pipe by setting up a circulating pump and circulating pipes in the falling film evaporator and connecting the circulating pipes to the branch spray pipes in the area away from the main spray pipe. This avoids incomplete spraying of heat exchange tubes in the branch spray pipe area away from the main spray pipe, improves heat exchange uniformity, and greatly enhances heat exchange efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the refrigerant spraying system of the falling film evaporator according to an embodiment of the present invention.

[0019] Explanation of reference numerals in the attached figures:

[0020] Falling film evaporator 100

[0021] Casing 11

[0022] Main sprinkler pipe 12

[0023] Branch sprinkler pipe 13

[0024] Circulation pipe 14

[0025] Circulation pump 15 Detailed Implementation

[0026] The present invention will be described more clearly and completely below by way of embodiments and in conjunction with the accompanying drawings, but the present invention is not limited to the scope of the embodiments.

[0027] like Figure 1 As shown, this embodiment includes a falling film evaporator 100.

[0028] The falling film evaporator 100 includes: a shell 11, heat exchange tubes, a main spray pipe 12, branch spray pipes 13, a circulation pipe 14, and a circulation pump 15. The heat exchange tubes are coiled inside the shell 11. Multiple branch spray pipes 13 are arranged at intervals. Refrigerant flows into the branch spray pipes 13 from the main spray pipe 12 and is sprayed into the shell 11 through the branch spray pipes 13. One end of the circulation pipe 14 is connected to the bottom of the shell 11, and the other end of the circulation pipe 14 is connected to the branch spray pipes 13 that are away from the main spray pipe 12. The circulation pump 15 is located in the circulation pipe 14 and is used to transport the coolant in the shell 11 to the branch spray pipes 13. By installing a circulating pump 15 and a circulating pipe 14 in the falling film evaporator 100, and connecting the circulating pipe 14 to a branch spray pipe 13 that is far from the main spray pipe 12, the flow rate of the branch spray pipe 13 in the area far from the main spray pipe 12 can be increased. This can prevent the heat exchange tubes in the branch spray pipe 13 area from being sprayed in the area far from the main spray pipe 12, improve the heat exchange uniformity, and greatly improve the heat exchange efficiency. This allows the compressor unit to achieve the required cooling capacity and improves the overall performance of the compressor unit.

[0029] In the figure, multiple branch spray pipes 13 are arranged symmetrically relative to the main spray pipe 12; the branch spray pipes 13 on both sides away from the main spray pipe 12 are all connected to the circulation pipe 14.

[0030] In one embodiment, the falling film evaporator 100 includes two sets of circulation pipes 14 and circulation pumps 15, which are symmetrically arranged relative to the main spray pipe 12.

[0031] Combination Figure 1 Branch spray pipe 13 is located above shell 11, and refrigerant is sprayed into shell 11 from top to bottom.

[0032] In this example, the falling film evaporator 100 includes four branch spray pipes 13. Two branch spray pipes 13 are provided on both sides of the main spray pipe 12. The circulation pipe 14 is connected to the two branch spray pipes 13 that are far away from the main spray pipe 12.

[0033] In the refrigerant spray distribution system of the compressor unit, although the branch spray pipes 13 are intermittently splitting or merging, as the number of branch spray pipes 13 increases and the branch spacing decreases, the refrigerant flow can be considered to continuously flow along the main spray pipe 12. This results in relatively low refrigerant flow on both sides of the falling film evaporator 100, leading to incomplete spraying of the heat exchange tubes on both sides, causing uneven heat exchange efficiency and affecting the compressor unit's cooling capacity. The falling film evaporator 100 with a circulating pump 15 in this example can effectively cover the areas on both sides of the shell 11 that are not properly sprayed, thereby greatly improving heat exchange efficiency and enabling the compressor unit to achieve the required cooling capacity, thus improving the overall performance of the compressor unit. This example can improve the heat exchange efficiency of the falling film evaporator 100 and avoid uneven spraying of the heat exchange tubes.

[0034] In this example, the falling film evaporator 100 is assisted by a circulating pump 15 for spraying, which ensures that the thin liquid film outside the spray pipe is fully sprayed, thus guaranteeing the heat exchange effect inside the falling film evaporator 100. The circulating pump 15 has a simple structure, is easy to install, maintain, and replace. The branch spray pipe 13 layout facilitates better spraying of the refrigerant. The circulating pump 15 can maintain the pressure and flow rate inside the falling film evaporator 100. The circulating pump 15 is self-powered, enabling the equipment to operate efficiently with low noise, which can improve heat exchange efficiency.

[0035] Combination Figure 1 The diagram clearly shows the spray flow path of the falling film evaporator 100 with a circulating pump 15. The circulating pump 15 draws the refrigerant from the bottom of the shell 11 of the falling film evaporator 100 to the branch spray pipes 13 for spraying. This covers areas on both sides of the falling film evaporator 100 that might otherwise be missed by the spray, ensuring the refrigerant liquid film completely covers the surface of the heat exchange tubes, achieving efficient heat exchange and improving the performance and heat exchange efficiency of the entire compressor unit. The structure of the falling film evaporator 100 mainly includes the circulating pump 15, a liquid seal orifice plate, and spray pipes. The design is relatively simple, the structure is stable, the piping is clear, facilitating pipe installation and replacement. The reasonable piping design ensures effective refrigerant spraying in the spray pipes. The falling film evaporator 100 has wide applicability. The falling film evaporator 100 in this example can meet different usage requirements, exhibiting high efficiency and stability. Targeted spraying based on the spraying effect within the falling film evaporator 100 can meet usage requirements under different conditions, demonstrating its wide applicability.

[0036] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. A falling film evaporator, characterized in that, The falling film evaporator includes: case; Heat exchange tubes, wherein the heat exchange tube coils are disposed within the housing; The main spray pipe and multiple branch spray pipes are arranged at intervals. The refrigerant flows from the main spray pipe into the branch spray pipes and is sprayed onto the shell through the branch spray pipes. A circulation pipe and a circulation pump are provided. One end of the circulation pipe is connected to the bottom of the housing, and the other end of the circulation pipe is connected to the branch spray pipe that is away from the main spray pipe. The circulation pump is located in the circulation pipe and is used to transport the coolant in the housing to the branch spray pipe.

2. The falling film evaporator as described in claim 1, characterized in that, The branch spray pipes are arranged symmetrically relative to the main spray pipe; the branch spray pipes on both sides away from the main spray pipe are all connected to the circulation pipe.

3. The falling film evaporator as described in claim 1, characterized in that, The falling film evaporator includes two sets of circulation pipes and circulation pumps, which are symmetrically arranged relative to the main spray pipe.

4. The falling film evaporator as described in claim 1, characterized in that, The branch spray pipe is located above the housing, and refrigerant is sprayed into the housing from top to bottom.

5. The falling film evaporator as described in claim 1, characterized in that, The falling film evaporator includes four branch spray pipes. Two branch spray pipes are respectively provided on both sides of the main spray pipe. The circulation pipe is connected to the two branch spray pipes that are away from the main spray pipe.

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