Vacuum cooling device for silicone oil molecular distillation

Abstract

The utility model belongs to the technical field of silicone oil fraction purification processing, and discloses a vacuum cooling device for silicone oil molecular distillation, which comprises a vacuum condensation cavity, a cooling coil is arranged in the vacuum condensation cavity, a cooling liquid circulating device is arranged on one side of the vacuum condensation cavity, and a cooling liquid outlet is formed in the other side of the vacuum condensation cavity. The cooling coil penetrates through the side wall of the vacuum condensation cavity and is in sealed connection with a cooling liquid circulating device, the top and the bottom of the vacuum condensation cavity are both in sealed connection with three-way sealing joints, and the vacuum condensation cavity flows out of a vacuum negative pressure pipeline and a steam output pipeline through the top portions of the three-way sealing joints. The device is compact and reasonable in structural design, high-temperature silicone oil steam molecules can be cooled, impurities and low-molecular silicone oil in the high-temperature silicone oil steam molecules can be condensed and separated, the condensation efficiency of the device is high, the condensation temperature control precision is high, and the device is suitable for large-scale production. And the production efficiency and the production quality can be greatly improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of silicone oil fraction purification processing, specifically to a vacuum cooling device for silicone oil molecular distillation. BACKGROUND

[0002] Silicone oil, as an important class of organosilicon polymers, has a wide range of applications in numerous fields due to its unique chemical structure and excellent properties, such as good thermal stability, low surface tension, high insulation, etc. in cosmetics, medical, electronic, mechanical and other industries. However, the unpurified silicone oil often contains impurities and components of different molecular weights, which will affect its performance and application effect. Therefore, it is particularly important to purify silicone oil by molecular distillation.

[0003] Molecular distillation, as an efficient separation technology, plays a key role in the purification process of silicone oil. It is a non-equilibrium distillation under high vacuum conditions, based on the difference in the average free path of different molecules to achieve separation. In the molecular distillation process, the silicone oil mixture is heated and evaporated, and the light molecules can quickly escape from the evaporation surface and reach the condensation surface due to their larger average free path, while the heavy molecules are difficult to reach the condensation surface due to their smaller average free path, thus realizing the separation of silicone oil of different molecular weights and impurities. The purity and performance of the silicone oil purified by molecular distillation can be significantly improved, better meeting the demand for high-quality silicone oil in various fields.

[0004] However, in the existing molecular distillation device for silicone oil, there are some problems affecting the distillation effect and product quality. Among them, the problem of condensation is more prominent. On the one hand, in the existing device, the temperature difference between the first end and the last end of the condensing tube is large during the condensation process. During the cooling process, the cooling liquid exchanges heat with the high-temperature silicone oil vapor at the first end, and the temperature gradually rises. When it flows to the last end, its cooling capacity has decreased, resulting in a relatively high temperature at the last end of the condensing tube. The high temperature at the last end makes it difficult for impurities and low molecular silicone oil to condense fully, which cannot be effectively separated from the system, greatly affecting the impurity removal effect. When trying to solve the problem of condensation at the last end by adjusting the overall condensation temperature, a new situation will be caused. At the first end, the lower temperature will cause the silicone oil that should be condensed at the next stage at a more suitable temperature to condense prematurely. This premature condensation disrupts the normal distillation and separation order, causing different molecular weight silicone oil fractions to mix with each other, resulting in a significant reduction in separation purity and ultimately leading to a product quality that cannot meet the expected standards.

[0005] On the other hand, in the condensation process, the steam molecules are easily adsorbed on the cooling pipe when condensing on the surface of the cooling pipe, and are gathered to form a liquid film by the surface tension of the liquid. This phenomenon is mainly due to the interaction between the steam molecules after losing energy on the surface of the cooling pipe, which promotes them to gather together. Once the liquid film is formed, it is like setting a thermal resistance barrier between the steam molecules and the cooling pipe. The steam molecules need to pass through the liquid film first to exchange heat with the cooling pipe, which greatly increases the resistance of heat transfer, resulting in a sharp decrease in heat exchange efficiency. The decrease in heat exchange efficiency not only prolongs the time of the entire distillation process, reduces the production efficiency, but also further affects the separation effect of the distillate and the product quality. Practical new type content

[0006] (I) The technical problem solved

[0007] In view of the deficiencies of the prior art, the utility model provides a vacuum cooling device for silicon oil molecular distillation to solve the problems of the existing condensing device, such as large temperature difference between the first end and the terminal, which affects the distillate purification quality and the like.

[0008] (II) Technical scheme

[0009] In order to achieve the above purpose, the utility model provides the following technical scheme: a vacuum cooling device for silicon oil molecular distillation, comprising a vacuum condensation cavity, a cooling coil is arranged in the vacuum condensation cavity, a cooling liquid circulating device is arranged on one side of the vacuum condensation cavity, the cooling coil is sealingly connected with the cooling liquid circulating device through the side wall of the vacuum condensation cavity, three-way sealing joints are sealingly connected to the top and the bottom of the vacuum condensation cavity, the vacuum condensation cavity is connected to a vacuum negative pressure pipeline and a steam output pipeline through the top of the three-way sealing joint, and the bottom of the vacuum condensation cavity is connected to a low molecular separation material pipe and a steam input pipeline.

[0010] Preferably, the cooling coil is a spiral structure, a plurality of flow guide rods are arranged at the spiral core, a liquid inlet is arranged at the top of the cooling coil, and a liquid outlet is arranged at the bottom of the cooling coil; the liquid inlet and the liquid outlet are arranged on the outer wall of the vacuum condensation cavity.

[0011] Preferably, the cooling liquid circulating device comprises a first cooling liquid cavity, a second cooling liquid cavity and a refrigerator, the first cooling liquid cavity and the second cooling liquid cavity are filled with cooling liquid, and the bottom of the first cooling liquid cavity is provided with a refrigerator.

[0012] Preferably, a first liquid pump is arranged at the upper part of the first cooling liquid cavity, the output end of the first liquid pump is sealingly connected with a transfer pipeline, the other end of the transfer pipeline extends to the top of the second cooling liquid cavity, the liquid outlet is sealingly connected with the first cooling liquid cavity through a connecting pipeline, and the output port is arranged at the bottom of the first cooling liquid cavity.

[0013] Preferably, the second cooling liquid cavity bottom is provided with a second liquid pump and a temperature sensor, and the output end of the second liquid pump is connected with the liquid inlet through a connecting pipeline.

[0014] (III) Beneficial effects

[0015] Compared with the prior art, the vacuum cooling device for silicon oil molecular distillation has the following beneficial effects:

[0016] 1. The vacuum cooling device for silicon oil molecular distillation is provided with a vacuum condensation cavity, a cooling coil and a cooling liquid circulating device, can cool and cool the high-temperature silicon oil vapor molecules, can condense and separate the impurities and low-molecular silicon oil therein, and has high condensation efficiency, high condensation temperature control precision, and can greatly improve the production efficiency and production quality.

[0017] 2. The flow guide rod is arranged, the flow guide rod can guide and adsorb the condensed liquid on the cooling coil, can prevent the liquid from covering the cooling coil to affect heat exchange, can greatly improve the condensation efficiency of the device, and the device has high distillation efficiency and high production efficiency.

[0018] 3. The cooling liquid circulating device is arranged, the temperature of the cooling liquid can be accurately controlled through the two groups of cooling liquid cavities and the temperature sensor, and the cooling efficiency is high, the condensation temperature control is accurate, the distillation quality is greatly improved, and the production quality is good. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a whole structure schematic view of the utility model;

[0020] Figure 2 It is a vacuum condensation cavity schematic view of the utility model;

[0021] Figure 3 It is a cooling liquid circulating device schematic view of the utility model;

[0022] Figure 4 It is a cooling liquid circulating device schematic view of the utility model.

[0023] In the drawing: 1, vacuum condensation cavity; 2, cooling coil; 3, cooling liquid circulating device; 4, three-way sealing joint; 5, vacuum negative pressure pipeline; 6, vapor output pipeline; 7, low-molecular separation pipeline; 8, vapor input pipeline; 9, flow guide rod; 10, liquid inlet; 11, liquid outlet; 12, first cooling liquid cavity; 13, second cooling liquid cavity; 14, refrigerator; 15, first liquid pump; 16, transfer pipeline; 17, second liquid pump. DETAILED DESCRIPTION

[0024] Clearly, the described embodiments are merely a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts under the premise that no creative efforts are made, belong to the scope of protection of the present application.

[0025] Please refer to Figures 1-4 The present application provides a technical scheme:

[0026] A vacuum cooling device for silicon oil molecular distillation, comprising a vacuum condensation cavity 1, a cooling coil 2 is arranged in the vacuum condensation cavity 1, a cooling liquid circulating device 3 is arranged on one side of the vacuum condensation cavity 1, the cooling coil 2 is sealingly connected with the cooling liquid circulating device 3 through penetrating the side wall of the vacuum condensation cavity 1, three-way sealing joints 4 are sealingly connected to the top and bottom of the vacuum condensation cavity 1, the vacuum condensation cavity 1 is connected to a vacuum negative pressure pipeline 5 and a steam output pipeline 6 through the top three-way sealing joints 4, and the vacuum condensation cavity 1 is connected to a low molecular separation material pipeline 7 and a steam input pipeline 8 through the bottom three-way sealing joints 4. The vacuum negative pressure pipeline 5 is connected to a vacuum negative pressure machine to perform vacuumization, so as to provide a vacuum environment for separation, and the low molecular separation material pipeline 7 is used to discharge low molecular silicon oil and part of impurities condensed into a liquid state. The low molecular separation material pipeline 7 can also be used to discharge some condensed liquid substances through a fractional condensation process, that is, gradually reducing the condensation temperature to make different molecular weights condense at different stages.

[0027] Further, the cooling coil 2 is in a spiral structure, a plurality of flow guide rods 9 are arranged at the spiral core of the cooling coil 2, a liquid inlet 10 is arranged at the top of the cooling coil 2, and a liquid outlet 11 is arranged at the bottom of the cooling coil 2. The liquid inlet 10 and the liquid outlet 11 are arranged on the outer wall of the vacuum condensation cavity 1. The flow guide rods 9 slightly contact the cooling coil 2 and are used to guide the flow of condensed liquid downward along the flow guide rods 9, so as to prevent steam molecules from being condensed and adsorbed on the cooling coil 2 and from being gathered and covered to form a liquid film through surface tension of the liquid. The liquid film will affect the contact and heat exchange between the steam molecules and the cooling coil 2, which will reduce the heat exchange efficiency and affect the distillation efficiency. The cooling coil 2 is provided with a unique upper liquid inlet, that is, the cooling liquid with a relatively low temperature enters from the upper part, flows downward along the spiral cooling coil 2 to exchange heat, and the high-temperature cooling liquid after heat exchange is discharged from the lower end. Compared with the traditional method, the present method needs a faster cooling liquid flow rate and a high precision of cooling liquid temperature control. The high-speed cooling liquid has a high cooling efficiency from top to bottom, and the high flow rate can make the temperature difference between the upper end and the lower end of the cooling coil 2 smaller, that is, the condensation temperature precision is higher, which is beneficial to improving the distillation quality.

[0028] Further, the cooling liquid circulating device 3 comprises a first cooling liquid cavity 12, a second cooling liquid cavity 13 and a refrigerating device 14, the first cooling liquid cavity 12 and the second cooling liquid cavity 13 are filled with cooling liquid, and the bottom of the first cooling liquid cavity 12 is provided with the refrigerating device 14. The refrigerating device 14 is preferably a refrigerating device based on thermoelectric effect. The refrigerating device based on Carnot cycle has a large area requirement and has a poor refrigerating effect at high temperature. The distillation condensation temperature of silicon oil molecules has different temperature ranges according to different processes, and is usually 50-150 degrees Celsius. The liquid cooling circulating device adopts a double liquid cavity mode, wherein the first cooling liquid cavity 12 is used as a cooling cooling liquid, and the second cooling liquid cavity 13 is used as a temperature detection for precise control.

[0029] Further, the first cooling liquid cavity 12 is provided with a first liquid pump 15 at the top, the output end of the first liquid pump 15 is sealingly connected with a transfer pipeline 16, the other end of the transfer pipeline 16 extends to the top of the second cooling liquid cavity 13, the liquid outlet 11 is sealingly connected with the first cooling liquid cavity 12 through a connecting pipeline, and the output port is arranged at the bottom of the first cooling liquid cavity 12. Different from the traditional liquid cooling mode, the device adopts a unique top liquid inlet, the high-temperature cooling liquid circulating through the cooling coil 2 enters the bottom of the first cooling liquid cavity 12 near the cold end of the refrigerating device 14, so as to facilitate cooling, and the first liquid pump 15 and the transfer pipeline 16 can transfer the cooled cooling liquid in the first cooling liquid cavity 12 to the second cooling liquid cavity 13. The first liquid pump 15 must be arranged at the top of the first cooling liquid cavity 12. If it is arranged at the bottom, the low-temperature liquid in the first cooling liquid cavity 12 and the high-temperature liquid just discharged from the cooling coil 2 may be extracted, which will affect the subsequent temperature detection and the stability of the system.

[0030] Further, the second cooling liquid cavity 13 is provided with a second liquid pump 17 and a temperature sensor at the bottom, and the output end of the second liquid pump 17 is sealingly connected with the liquid inlet 10 through a connecting pipeline. According to the principle of thermal convection, the hotter liquid will rise, and the cooler liquid will sink to the bottom, so the second liquid pump 17 is arranged at the bottom of the second cooling liquid cavity 13.

[0031] Structure description:

[0032] The vacuum condensing cavity 1 is a cavity, which is the core part of the device, used for accommodating the cooling coil 2 and providing a silicon oil vapor cooling space. The top and bottom of the vacuum condensing cavity 1 are provided with three-way sealing joints 4, which are connected with a vacuum negative pressure pipeline 5, a vapor output pipeline 6, a low-molecular separation pipeline 7 and a vapor input pipeline 8 respectively.

[0033] The cooling coil 2 is a spiral structure, located in the vacuum condensing cavity 1, connected with the cooling liquid circulating device 3 through the liquid inlet 10 and the liquid outlet 11, used for cooling silicon oil vapor, and the flow guide rod 9 at the center of the spiral can guide the condensed liquid to prevent the liquid film from affecting heat exchange.

[0034] Cooling liquid circulating device 3: composed of first cooling liquid cavity 12, second cooling liquid cavity 13 and refrigerator 14, used for adjusting the temperature of cooling liquid, ensuring the high efficiency of cooling coil 2, and sealingly connected with cooling coil 2 through connecting pipeline;

[0035] Three-way sealing joint 4: located at the top and bottom of vacuum condensing cavity 1 respectively, used for distributing pipeline, realizing the transportation of vacuum, steam and material, and sealingly connecting vacuum condensing cavity 1 with each pipeline;

[0036] Vacuum negative pressure pipeline 5: one end connected with three-way sealing joint 4 at the top of vacuum condensing cavity 1, and the other end connected with vacuum negative pressure machine, used for extracting air in vacuum condensing cavity 1, creating vacuum environment, and ensuring the smooth progress of molecular distillation;

[0037] Steam output pipeline 6: connected with three-way sealing joint 4 at the top of vacuum condensing cavity 1, used for discharging silicon oil steam after condensation and low molecule removal, and transporting it to the next process;

[0038] Low molecule separation pipeline 7: connected with three-way sealing joint 4 at the bottom of vacuum condensing cavity 1, used for discharging low molecule silicon oil and impurities after condensation, and realizing the separation of silicon oil molecules and impurities;

[0039] Steam input pipeline 8: connected with three-way sealing joint 4 at the bottom of vacuum condensing cavity 1, used for inputting high temperature silicon oil steam;

[0040] Flow guide rod 9: located at the screw core of cooling coil 2, slightly contacting with cooling coil 2, used for guiding the condensed liquid on cooling coil 2, preventing the formation of liquid film, and improving the heat exchange efficiency;

[0041] Liquid inlet 10: located at the top of cooling coil 2, being the inlet of cooling liquid into cooling coil 2, and connected with second cooling liquid cavity 13 in cooling liquid circulating device 3 through connecting pipeline;

[0042] Liquid outlet 11: located at the bottom of cooling coil 2, being the outlet of cooling liquid out of cooling coil 2, and connected with first cooling liquid cavity 12 in cooling liquid circulating device 3 through connecting pipeline;

[0043] First cooling liquid cavity 12: containing cooling liquid inside, having refrigerator 14 at the bottom, used for cooling the high temperature cooling liquid flowing out of cooling coil 2, and connected with liquid outlet 11 of cooling coil 2 and transfer pipeline 16 through connecting pipeline;

[0044] Second cooling liquid cavity 13: containing cooling liquid inside, having second liquid pump 17 and temperature sensor at the bottom, used for storing the cooling liquid after temperature reduction in first cooling liquid cavity 12, and providing cooling liquid for cooling coil 2, and connected with transfer pipeline 16 and liquid inlet 10 of cooling coil 2 through connecting pipeline;

[0045] Refrigerator 14: installed at the bottom of the first cooling liquid cavity 12, used to cool the cooling liquid in the first cooling liquid cavity 12, to ensure that the temperature of the cooling liquid meets the cooling requirements;

[0046] First liquid pump 15: located at the upper part of the first cooling liquid cavity 12, through the transfer pipe 16, the cooled cooling liquid in the first cooling liquid cavity 12 is transported to the second cooling liquid cavity 13, to maintain the circulation of the cooling liquid;

[0047] Transfer pipe 16: one end is connected to the output end of the first liquid pump 15 in the first cooling liquid cavity 12, and the other end extends to the top of the second cooling liquid cavity 13, used for transferring the cooling liquid;

[0048] Second liquid pump 17: located at the bottom of the second cooling liquid cavity 13, used to transport the cooling liquid in the second cooling liquid cavity 13 to the liquid inlet 10 of the cooling coil 2, to ensure the continuous circulation of the cooling liquid.

[0049] Working principle: when the device is started, the vacuum negative pressure machine is connected with the vacuum condensing cavity 1 through the vacuum negative pressure pipeline 5, and the vacuum condensing cavity 1 is started to be vacuumized. In the process of molecular distillation, the vacuum environment is very important, which can reduce the pressure of the system, reduce the average free path of molecules, and make the silicon oil vapor molecules more easily escape and separate. When the pressure in the vacuum condensing cavity is reduced to a suitable range, it creates necessary conditions for subsequent distillation cooling. High-temperature silicon oil vapor enters the vacuum condensing cavity 1 through the vapor input pipeline 8. At this time, the cooling coil 2 in the vacuum condensing cavity 1 begins to play a key role. The cooling coil 2 is in a spiral structure, and the top is provided with a liquid inlet 10, and the bottom is provided with a liquid outlet 11. The cooling liquid with lower temperature enters the cooling coil 2 from the liquid inlet 10. This unique upper end liquid inlet mode enables the cooling liquid to spiral down along the cooling coil 2 and fully exchanges heat with the high-temperature silicon oil vapor. In the heat exchange process, the heat of the silicon oil vapor molecules is taken away by the cooling liquid, and the temperature gradually decreases, and then the condensation phenomenon occurs. With the condensation of the silicon oil vapor, the impurities and low molecular silicon oil therein are condensed into liquid state first. These liquid substances will flow down along the surface of the cooling coil 2 due to gravity. A plurality of flow guide rods 9 are arranged at the spiral core of the cooling coil 2, and the flow guide rods 9 slightly contact the cooling coil 2. When the condensed liquid contacts the surface of the cooling coil 2, the flow guide rods 9 play a role of guiding flow, guiding the liquid to flow down along the flow guide rods 9, avoiding the vapor molecules from being condensed and adsorbed on the cooling coil 2, and then being gathered and covered by the liquid film through the surface tension. Because the existence of the liquid film will seriously affect the contact heat exchange between the vapor molecules and the cooling coil 2, reduce the heat exchange efficiency, and then affect the purification distillation efficiency. The condensed low molecular silicon oil and part of the impurities are discharged from the low molecular separation pipe 7 at the bottom of the vacuum condensing cavity 1. If a staged condensation process is adopted, that is, the condensation temperature is gradually reduced, silicon oils with different molecular weights will condense at different stages, and the low molecular separation pipe 7 is used to discharge the liquid substances condensed at each stage, so as to realize effective separation of silicon oils with different molecular weights. The cooling liquid circulating device 3 plays a key role in temperature regulation in the whole process. It includes a first cooling liquid cavity 12, a second cooling liquid cavity 13 and a refrigerator 14. The cooling liquid circulates between the first cooling liquid cavity 12 and the second cooling liquid cavity 13 to realize accurate temperature control. The high-temperature cooling liquid discharged from the liquid outlet 11 at the bottom of the cooling coil 2 enters the first cooling liquid cavity 12 through the connecting pipeline, which is close to the cold end of the refrigerator 14, so as to be quickly cooled. The first liquid pump 15 arranged at the top of the first cooling liquid cavity 12 transfers the cooled cooling liquid to the top of the second cooling liquid cavity 13 through the transfer pipeline 16. It should be noted that the first liquid pump 15 must be arranged at the top of the first cooling liquid cavity 12. If it is arranged at the bottom, it may extract the low-temperature liquid in the first cooling liquid cavity 12 and the high-temperature liquid just discharged from the cooling coil 2, which will seriously affect the subsequent temperature detection and the stability of the system.In the second cooling liquid cavity 13, due to the principle of heat convection, the hotter liquid rises, and the cooler liquid sinks to the bottom. The second liquid pump 17 and the temperature sensor are arranged at the bottom of the second cooling liquid cavity 13. The second liquid pump 17 extracts the cooling liquid with relatively low temperature and stability from the bottom, and delivers it to the liquid inlet 10 at the top of the cooling coil 2 through the connecting pipeline, and participates in the cooling process of the silicone oil vapor again. The temperature sensor monitors the temperature of the cooling liquid in the second cooling liquid cavity 13 in real time, and feeds back the data to the system, so as to adjust the working state of the refrigeration device 14, ensure that the temperature of the cooling liquid is always in the appropriate range, and realize precise control of the condensation temperature. This unique cooling liquid circulation mode, especially the double-liquid-cavity design and the unique liquid inlet, outlet and circulation path, can meet the high requirements of the cooling liquid flow rate and temperature control precision of the cooling coil 2 liquid inlet mode at the upper end. The high-speed flowing cooling liquid cools from top to bottom, not only improves the cooling efficiency, but also makes the temperature difference between the upper and lower ends of the cooling coil 2 smaller, further ensures the improvement of the condensation temperature precision, is beneficial to improve the distillate quality, and realizes the efficient and precise silicone oil molecular distillation vacuum cooling process. In summary, through the cooperative work of each part of the vacuum cooling device, from the construction of the vacuum environment, the condensation and separation of the silicone oil vapor, to the circulation and temperature control of the cooling liquid, each link is closely matched, and the efficient cooling of the silicone oil molecular distillation is realized, which provides a strong guarantee for producing high-quality silicone oil products.

[0050] Although the embodiments of the utility model have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the utility model, the scope of the utility model is defined by the appended claims and their equivalents.

Claims

1. A vacuum cooling device for the molecular distillation of silicone oils, comprising a vacuum condensation chamber (1), characterized in that: The vacuum condensation cavity (1) is provided with a cooling coil (2), one side of the vacuum condensation cavity (1) is provided with a cooling liquid circulating device (3), the cooling coil (2) is in sealing connection with the cooling liquid circulating device (3) through the side wall of the vacuum condensation cavity (1), the top and the bottom of the vacuum condensation cavity (1) are in sealing connection with a three-way sealing joint (4), the vacuum condensation cavity (1) is in outflow through the three-way sealing joint (4) top, a vacuum negative pressure pipeline (5) and a steam output pipeline (6), the bottom of the vacuum condensation cavity (1) is in outflow through a low molecular separation material pipe (7) and a steam input pipeline (8).

2. A vacuum cooling device for the molecular distillation of silicone oil according to claim 1, characterized in that: The cooling coil (2) is a spiral structure, a plurality of flow guide rods (9) are arranged at the spiral core, the top of the cooling coil (2) is provided with an inlet (10), the bottom of the cooling coil (2) is provided with an outlet (11), and the inlet (10) and the outlet (11) are arranged on the outer wall of the vacuum condensation cavity (1).

3. A vacuum cooling apparatus for the molecular distillation of silicone oil according to claim 2, characterized in that: The cooling liquid circulating device (3) comprises a first cooling liquid cavity (12), a second cooling liquid cavity (13) and a refrigerator (14), the first cooling liquid cavity (12) and the second cooling liquid cavity (13) are filled with cooling liquid, and the bottom of the first cooling liquid cavity (12) is provided with the refrigerator (14).

4. A vacuum cooling apparatus for the molecular distillation of silicone oil according to claim 3, characterized in that: The first liquid pump (15) is arranged at the top of the first cooling liquid cavity (12), the output end of the first liquid pump (15) is in sealing connection with a transfer pipeline (16), the other end of the transfer pipeline (16) extends to the top of the second cooling liquid cavity (13), the outlet (11) is in sealing connection with the first cooling liquid cavity (12) through a connecting pipeline, and the output port is arranged at the bottom of the first cooling liquid cavity (12).

5. A vacuum cooling apparatus for the molecular distillation of silicone oil according to claim 4, characterized in that: The second liquid pump (17) and a temperature sensor are arranged at the bottom of the second cooling liquid cavity (13), and the output end of the second liquid pump (17) is in sealing connection with the inlet (10) through a connecting pipeline.

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