A cold trap

Abstract

The application provides a cold trap, comprising: a cold trap body; a wall scraping stirring piece arranged in the cold trap body and used for cleaning the blockage of the inner wall of the cold trap body when the cold trap is blocked; and a support fixedly arranged on the bottom surface of the cold trap body, wherein the top surface of the support is in abutment with the wall scraping stirring piece and used for supporting the wall scraping stirring piece; and the distance between the wall scraping stirring piece and the outer periphery of the cold trap body is less than 1.5 mm. The implementation of the application can continuously scrape the condensate or high-viscosity material attached to the inner wall during the condensation process, and effectively prevent the condensate or high-viscosity material from being accumulated to form blockage.

Description

Technical Field

[0001] This application relates to the field of reaction vessel equipment technology, specifically to a cold trap. Background Technology

[0002] In the polyester synthesis process, the vacuum system is one of the key pieces of equipment to ensure the efficient and stable progress of the reaction. Its main function is to promptly remove small-molecule byproducts generated during the reaction, promote the reaction in the forward direction, and maintain the high vacuum environment required by the reaction system. The cold trap, as an important component of the vacuum system, is usually located between the reactor and the vacuum pump. Its main purpose is to condense and recover low-boiling-point byproducts (such as ethylene glycol and water) generated during the reaction, preventing these volatile substances from entering the vacuum pump and causing problems such as lubricant emulsification, pump corrosion, or a decline in vacuum performance.

[0003] However, in existing vacuum systems of polyester reactors, the cold traps mostly employ simple jacketed cooling structures, with the cooling medium flowing within the jacket to indirectly cool the inner cavity of the cold trap. During prolonged continuous operation, byproduct vapors continuously condense and accumulate on the inner wall of the cold trap, especially at low temperatures, easily forming solid or high-viscosity condensates. Prolonged accumulation can easily cause blockage of the cold trap channels, leading to a decrease in system vacuum and reduced pumping efficiency, and in severe cases, even affecting the reaction process or causing reaction failure. Currently, the industry commonly uses manual disassembly and cleaning after shutdown to address the blockage problem. This not only increases the labor intensity of operators but also significantly reduces production continuity and overall efficiency. Furthermore, frequent shutdowns for cleaning not only disrupt the production rhythm but may also introduce dust, impurities, and other contaminants during disassembly and assembly, posing a risk of contaminating the reaction system and potentially threatening product quality stability.

[0004] Therefore, there is an urgent need to develop a new type of cold trap device that can effectively prevent cold trap blockage and has an online automatic cleaning function, so as to achieve stable operation and continuous operation of the vacuum system in the polyester synthesis process, improve production efficiency, reduce maintenance costs, and ensure the safety of the reaction process and the consistency of product quality. Summary of the Invention

[0005] In view of the above-mentioned problems in the prior art, the purpose of this application is to provide a reaction vessel to solve the problem of cross-contamination between dry and wet materials in the prior art.

[0006] To solve the above-mentioned technical problems, the specific technical solution of this application is as follows:

[0007] This application provides a cold trap, comprising:

[0008] Cold trap body;

[0009] A wall-scraping agitator is disposed inside the cold trap body and is used to clean the blockage on the inner wall of the cold trap body when the cold trap is blocked.

[0010] A bracket is fixedly installed on the bottom surface of the cold trap body, and the top surface of the bracket abuts against the wall scraping and stirring component to support the wall scraping and stirring component.

[0011] The distance between the wall-scraping agitator and the outer periphery of the cold trap body is less than 1.5 mm.

[0012] Optionally, the wall-scraping agitator includes: a scraper and a rotating shaft;

[0013] The rotation axis is located at the axis of the cold trap body;

[0014] The scraper is fixedly disposed on the outer periphery of the rotating shaft, and the distance between the scraper and the outer periphery of the cold trap body is less than 1.5 mm.

[0015] Optionally, it may also include: a drive unit and a magnetic coupler;

[0016] The rotating shaft is connected to the driving component via the magnetic coupler.

[0017] Optionally, the outer wall of the cold trap body has a coolant inlet and a coolant outlet, with the coolant inlet located near the bottom surface of the cold trap body and the coolant outlet located near the top surface of the cold trap body.

[0018] Optionally, it also includes: a high-pressure spraying component, movably disposed between the rotating shaft and the scraper, the outlet of the high-pressure spraying component facing the inner wall of the cold trap body, the high-pressure spraying component being used to spray cleaning fluid onto the inner wall of the cold trap body.

[0019] Optionally, the high-pressure nozzle assembly includes: a nozzle and a pipeline that are interconnected;

[0020] The nozzle is disposed between the rotating shaft and the scraper, and the outlet of the nozzle faces the inner wall of the cold trap body;

[0021] One end of the pipe is connected to the nozzle, and the other end of the pipe passes through the outer wall of the cold trap body and is connected to an external liquid storage device or a liquid storage device.

[0022] Optionally, it may also include an electrically heated band disposed around the outer surface of the cold trap body.

[0023] Optionally, the magnetic coupler includes an outer magnetic rotor and an inner magnetic rotor, wherein the outer magnetic rotor is connected to the driving member and the inner magnetic rotor is connected to the rotating shaft.

[0024] Optionally, the outer wall of the cold trap body has a coolant inlet and a coolant outlet, with the coolant inlet located near the bottom surface of the cold trap body and the coolant outlet located near the top surface of the cold trap body.

[0025] Optionally, an air inlet is formed on the bottom surface of the cold trap body, and an air outlet is formed on the top surface of the cold trap body.

[0026] This application provides a cold trap. By installing a wall-scraping agitator inside the cold trap body and stably supporting it with a bracket, a precise gap of less than 1.5mm is maintained between the wall-scraping agitator and the inner wall of the cold trap body. This allows for the continuous scraping of condensate or high-viscosity materials adhering to the inner wall during the condensation process, effectively preventing their accumulation and blockage. When blockage occurs, the wall-scraping agitator can be activated online for mechanical cleaning without stopping the machine for disassembly. This significantly improves the continuity of cold trap operation and ease of maintenance, ensures the stable operation of the vacuum system, and enhances the safety and efficiency of the polyester reaction process.

[0027] To make the above and other objects, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A schematic diagram of a cold trap according to an embodiment of this application is shown;

[0030] 1-Cold trap body, 2-Air inlet, 3-Air outlet, 4-Coolant inlet, 5-Coolant outlet, 6-Support, 7-Wall scraping and stirring component, 8-Nozzle, 9-Pipeline, 10-Electric heating belt. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0033] To address the aforementioned problems, this application provides a cold trap, such as... Figure 1 As shown, this device is used in the vacuum system of a polyester reactor to efficiently condense and recover low-boiling-point byproducts (such as ethylene glycol and water vapor) generated during the reaction process, preventing them from entering the vacuum pump and causing pollution, corrosion, or performance degradation. The cold trap includes a cold trap body 1, a wall-scraping agitator 7, a support 6, a coolant inlet 4, a coolant outlet 5, an air inlet 2, and an air outlet 3. Its core function is to achieve online removal of condensate and emergency treatment of blockages through mechanical wall scraping, electric heating, and high-pressure spraying, thereby improving the continuity and stability of system operation.

[0034] The cold trap body 1 is a vertically positioned cylindrical pressure vessel, typically made of corrosion-resistant stainless steel (such as 316L), possessing good mechanical strength and sealing performance, capable of withstanding the internal and external pressure differences under vacuum conditions. Its interior forms a cavity for gas condensation. During prolonged operation, vapor condenses on the low-temperature walls and gradually accumulates, easily forming high-viscosity or semi-solid deposits, leading to channel blockage and affecting the vacuum level. Therefore, this application includes a wall-scraping agitator 7 inside the cold trap body 1, used to continuously scrape away condensate adhering to the inner wall during the condensation process, preventing its accumulation and blockage.

[0035] The wall-scraping agitator 7 is a longitudinally arranged rotating structure, with its outer edge maintaining a precise gap of less than 1.5 mm with the inner wall of the cold trap body 1, preferably 0.5–1.0 mm. This tiny gap effectively removes adhering substances while preventing damage to the scraper or the vessel wall due to friction. The scraper edge is made of polytetrafluoroethylene (PTFE), which has excellent chemical corrosion resistance, low surface energy, and self-lubricating properties, making it suitable for use in polyester synthesis processes involving corrosive media such as organic acids and ethylene glycol. The scraper can be a frame-type, anchor-type, or spiral-belt structure, fixed to the outer circumference of the rotating shaft and rotating synchronously with the shaft to achieve continuous scraping of the entire inner wall surface.

[0036] To support the stable rotation of the wall-scraping agitator 7, a bracket 6 is fixedly installed on the bottom surface of the cold trap body 1. The bracket 6 has a transverse "+" or "well" shaped structure, and its top surface abuts against or is connected to the lower end of the rotation axis of the wall-scraping agitator 7 through a bearing, serving as a support and positioning element. The design of the bracket 6 ensures that it does not affect the entry of gas from the air inlet 2 into the cold trap cavity, ensuring unobstructed airflow, while also preventing resonance or swaying during the stirring process.

[0037] The rotating shaft of the wall-scraping agitator 7 is positioned along the axial direction of the cold trap body 1, extending through the entire condensation chamber to ensure stable trajectory of the scraper during rotation. The rotating shaft can be made of stainless steel or titanium alloy, possessing sufficient rigidity and fatigue resistance. The scraper is fixed to the rotating shaft by screws or a retaining mechanism for easy disassembly and replacement. The distance between the scraper and the inner wall of the cold trap body 1 is controlled within the range of 0.5–1.5 mm through precision machining and assembly, ensuring effective scraping while minimizing wear.

[0038] To ensure stable driving of the wall-scraping agitator 7 and maintain system sealing, the rotating shaft is connected to an external drive component (such as a variable frequency motor) via a magnetic coupler. The magnetic coupler consists of an outer magnetic rotor and an inner magnetic rotor: the outer magnetic rotor is mounted on the output shaft of the drive motor, located outside the cold trap; the inner magnetic rotor is fixed to the upper end of the rotating shaft, located inside the cold trap cavity. A non-magnetic metal spacer separates the two, completely isolating the inner and outer spaces and achieving contactless torque transmission. When the drive motor rotates the outer magnetic rotor, the magnetic field induces the inner magnetic rotor to rotate synchronously, thereby driving the rotating shaft and scraper to rotate. Since a mechanical shaft seal penetrating the vessel wall is unnecessary, the problems of easy leakage and wear under vacuum conditions inherent in traditional sealing structures are completely avoided, improving the system's sealing reliability and service life. The drive component is preferably a speed-adjustable motor, with the speed adjusted by a controller to adapt to the wall-scraping requirements under different operating conditions.

[0039] The outer wall of the cold trap body 1 is equipped with a cooling jacket for introducing a cooling medium (such as an aqueous solution of ethylene glycol, cold water, or liquid nitrogen). The cooling jacket has a coolant inlet 4 and a coolant outlet 5. The coolant inlet 4 is located near the bottom surface of the cold trap body 1, and the coolant outlet 5 is located near the top surface, forming a bottom-up coolant flow path. This counter-flow design has significant advantages: after the high-temperature gas enters from the bottom inlet 2, it first contacts the lowest-temperature lower wall, which is conducive to the preferential condensation of high-boiling-point components; as the gas rises, the temperature gradually increases, preventing frost buildup at the top and blockage of the outlet 3. Simultaneously, the coolant flows from bottom to top, forming a counter-current heat exchange with the gas, resulting in a large temperature difference and high efficiency. The cooling jacket can adopt a spiral guide plate structure to extend the coolant flow path and increase the heat exchange area. The temperature of the cooling medium can be adjusted according to process requirements, typically controlled between -10℃ and 10℃.

[0040] To further enhance the emergency handling capability of the cold trap in case of blockage, this application adds a high-pressure spray component for online cleaning of the inner wall. The high-pressure spray component is movably positioned between the rotating shaft and the scraper, with its outlet facing the inner wall of the cold trap body 1. Specifically, the high-pressure spray component includes a nozzle 8 and a conduit 9: the nozzle 8 is fixed to the scraper frame or the side of the rotating shaft, with its nozzle angled towards the wall; one end of the conduit 9 connects to the nozzle 8, and the other end passes through a sealed joint on the outer wall of the cold trap body 1, connecting to an external liquid storage device (such as a cleaning fluid tank) or a high-pressure air source. The nozzle 8 can be designed as a telescopic rotating structure, achieving radial extension and angle adjustment via a pneumatic or electric actuator to ensure the spray range covers the entire inner wall surface of the cold trap. The conduit 9 uses a stainless steel flexible hose or a PTFE-lined tube, capable of withstanding the impact of high-pressure cleaning fluid (such as hot ethylene glycol, hot water, or compressed air). In some embodiments, multiple nozzles 8 can be provided, arranged in layers along the height direction of the rotating shaft to form a multi-stage spray network, improving cleaning coverage and efficiency.

[0041] The nozzle 8 and pipeline 9 of the high-pressure liquid spraying component are interconnected. The nozzle 8 is positioned between the rotating shaft and the scraper, ensuring that the nozzle orifice is directly facing the inner wall of the cold trap. The nozzle 8 can adopt a fan-shaped, conical, or multi-hole array design to expand the cleaning coverage area. A heat tracing layer can be installed on the outside of the pipeline 9 to prevent the cleaning fluid from freezing in low-temperature environments. The sealing joint adopts a metal bellows or O-ring sealing structure to ensure airtightness under high pressure.

[0042] To enhance unblocking capabilities, this application also adds an electric heating belt 10 to the outer surface of the cold trap body 1. The electric heating belt 10 is uniformly wound around the outer periphery of the cold trap body 1 and is located outside the cooling jacket. A self-regulating heating tape is preferably used, whose power automatically adjusts with temperature, and its operating temperature range is 50–150°C, with a target temperature that can be set according to process requirements. An insulation layer is provided on the outer side of the electric heating belt 10 to reduce heat loss and improve heating efficiency. When severe blockage occurs in the cold trap, the electric heating program can be activated: the coolant supply is cut off, the electric heating belt 10 is activated, and the temperature of the cold trap body 1 slowly rises, softening or melting the high-viscosity or solid blockage adhering to the inner wall. During this process, the wall-scraping agitator 7 is simultaneously activated for mechanical scraping, and a high-pressure spray nozzle can be used to spray cleaning fluid, achieving efficient unblocking through a three-in-one approach of "thermal melting + mechanical + fluid."

[0043] The magnetic coupler consists of an outer magnetic rotor and an inner magnetic rotor. The outer magnetic rotor is driven by a motor and contains a ring of permanent magnets. The inner magnetic rotor is fixed to a rotating shaft and also contains permanent magnets with corresponding poles. The two are separated by a non-magnetic metal spacer welded to the top flange of the cold trap body 1, achieving a complete seal. The air gap between the inner and outer magnetic rotors is controlled at 2–5 mm to ensure efficient magnetic field transmission while avoiding friction. This structure achieves complete isolation between the drive system and the cold trap cavity, making it suitable for applications requiring high vacuum and high cleanliness.

[0044] The bottom center region of the cold trap body 1 forms an inlet 2 for receiving the high-temperature vapor mixture from the reactor; the top center region forms an outlet 3 for exporting uncondensed gas to the subsequent vacuum system. The inlet 2 employs a tangential or straight-through design to guide the gas flow from bottom to top, extending the residence time and improving condensation efficiency. The outlet 3 is equipped with a filter or baffle to prevent droplets from being entrained into the vacuum pump. This layout facilitates uniform gas distribution and staged condensation, avoiding localized overcooling or blockage.

[0045] This application can also integrate temperature sensors, pressure sensors, and a PLC controller to achieve intelligent operation. The temperature sensor is installed inside the cold trap to monitor the wall or gas temperature; the pressure sensor is installed at the inlet 2 and outlet 3 to measure pressure difference changes and determine if blockage has occurred. All signals are connected to the controller, which automatically starts and stops the wall-scraping agitator 7, the electric heating belt 10, or the high-pressure spraying device according to preset logic. For example, when the pressure difference continuously rises above a set threshold and lasts for more than 5 minutes, the system determines it as a "potential blockage" and automatically starts the wall-scraping agitator 7 to accelerate its operation; if the pressure difference continues to rise to the warning value, a "serious blockage" alarm is triggered, and a combined unblocking procedure of heating + spraying + agitation is automatically executed. Operators can also manually start the cleaning process or adjust parameters through the human-machine interface.

[0046] This application is not only applicable to polyester synthesis, but can also be extended to other polycondensation reaction systems such as PET, PBT, and PC, as well as processes involving high-vacuum distillation or condensation recovery in the pharmaceutical, fragrance, and fine chemical industries. The cold trap body 1 can adopt an elliptical head or conical bottom structure to facilitate the discharge of condensate; the wall-scraping agitator 7 can adopt a planetary or double-layer agitation structure to adapt to the scraping requirements of materials with different viscosities; the electric heating belt 10 can be replaced with an infrared heating film or an electromagnetic induction heating device to improve heating efficiency.

[0047] In summary, this application constructs a multifunctional cold trap device integrating anti-clogging, anti-clogging, and emergency treatment by incorporating a wall-scraping agitator 7 inside the cold trap, an integrated external electric heating belt 10, and optionally a high-pressure liquid spraying system and a magnetic drive device. It features a compact structure, reliable operation, convenient maintenance, and a high degree of automation, effectively solving the technical problems of easy clogging and difficult cleaning in traditional cold traps.

[0048] It should also be understood that, in the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this application generally indicates that the preceding and following related objects have an "or" relationship.

[0049] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this application can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0050] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0051] In the embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the couplings or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections through some interfaces, apparatuses, or units, or they may be electrical, mechanical, or other forms of connection.

[0052] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments of this application, depending on actual needs.

[0053] This application uses specific embodiments to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A cold trap, characterized in that, include: Cold trap body (1); The wall-scraping agitator (7) is disposed inside the cold trap body (1) and is used to clean the blockage on the inner wall of the cold trap body (1) when the cold trap is blocked. The bracket (6) is fixedly installed on the bottom surface of the cold trap body (1). The top surface of the bracket (6) abuts against the wall scraping and stirring component (7) to support the wall scraping and stirring component (7). The distance between the scraping and stirring component (7) and the outer periphery of the cold trap body (1) is less than 1.5 mm.

2. The cold trap according to claim 1, characterized in that, The wall-scraping agitator (7) includes: a scraper and a rotating shaft; The rotation axis is located at the axis of the cold trap body (1); The scraper is fixedly disposed on the outer periphery of the rotating shaft, and the distance between the scraper and the outer periphery of the cold trap body (1) is less than 1.5 mm.

3. The cold trap according to claim 2, characterized in that, Also includes: Drive components and magnetic couplers; The rotating shaft is connected to the driving component via the magnetic coupler.

4. The cold trap according to claim 1, characterized in that, The outer wall of the cold trap body (1) has a coolant inlet (4) and a coolant outlet (5). The coolant inlet (4) is located near the bottom surface of the cold trap body (1), and the coolant outlet (5) is located near the top surface of the cold trap body (1).

5. The cold trap according to claim 2, characterized in that, Also includes: A high-pressure spray nozzle is movably disposed between the rotating shaft and the scraper. The outlet of the high-pressure spray nozzle faces the inner wall of the cold trap body (1). The high-pressure spray nozzle is used to spray cleaning fluid onto the inner wall of the cold trap body (1).

6. The cold trap according to claim 5, characterized in that, The high-pressure liquid injection component includes: a nozzle (8) and a pipeline (9) that are interconnected. The nozzle (8) is disposed between the rotating shaft and the scraper, and the outlet of the nozzle (8) faces the inner wall of the cold trap body (1); One end of the pipe (9) is connected to the nozzle (8), and the other end of the pipe (9) passes through the outer wall of the cold trap body (1) and is connected to the external liquid storage device.

7. The cold trap according to claim 5, characterized in that, Also includes: An electric heating band (10) is disposed around the outer surface of the cold trap body (1).

8. The cold trap according to claim 3, characterized in that, The magnetic coupler includes an outer magnetic rotor and an inner magnetic rotor, wherein the outer magnetic rotor is connected to the driving component and the inner magnetic rotor is connected to the rotating shaft.

9. The cold trap according to claim 1, characterized in that, The outer wall of the cold trap body (1) has a coolant inlet (4) and a coolant outlet (5). The coolant inlet (4) is located near the bottom surface of the cold trap body (1), and the coolant outlet (5) is located near the top surface of the cold trap body (1).

10. The cold trap according to claim 1, characterized in that, The bottom surface of the cold trap body (1) has an air inlet (2), and the top surface of the cold trap body (1) has an air outlet (3).

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