Dry ice temperature control device

Abstract

The utility model discloses a dry ice temperature control device belongs to temperature control technical field. The device includes dry ice bucket, pumping module and reaction tank. Dry ice bucket is equipped with heat exchange coil pipe, and pumping module is constituted by main pump and vice pump. Main pump drives circulation refrigerant to flow in the main circulation loop that is constituted by reaction tank, dry ice bucket heat exchange coil pipe and connecting pipeline, realizes the cooling of reaction tank. To solve the problem of air binding when the system starts, the device is provided with the starting branch that is constituted by vice pump, second solenoid valve and branch pipeline, and is parallelly connected with the main loop through the tee joint. The control unit can control the cooperative action of double pump and solenoid valve according to the preset program, realizes full -automatic or semi -automatic starting, and can adjust the main pump speed according to temperature sensor feedback, realizes accurate temperature control. The utility model has the advantages of reliable starting, accurate temperature control and compact structure, and is especially suitable for laboratory scene.

Description

Technical Field

[0001] This utility model relates to the field of temperature control technology, specifically to a low-temperature temperature control device that uses dry ice as a cold source, which is particularly suitable for precise cooling and constant temperature control of reaction tanks in laboratories or small-to-medium-scale production. Background Technology

[0002] In laboratory research and small-scale production in fields such as chemical synthesis, biopharmaceuticals, and materials science, it is often necessary to conduct reactions or preserve samples at low temperatures. Currently, the commonly used techniques for achieving and maintaining the required low-temperature environment suffer from the following main problems and shortcomings: 1. Traditional dry ice / ethanol bath. This is the most common temporary cryogenic solution in laboratories. This method typically involves directly immersing dry ice in an open container filled with organic solvents such as ethanol, creating a cryogenic environment through the sublimation and heat absorption of the dry ice. However, this method has significant drawbacks: Poor temperature control accuracy and large fluctuations: The temperature depends entirely on the amount and rate of dry ice addition, making it impossible to achieve precise closed-loop control, resulting in poor temperature uniformity in the reaction system.

[0003] It cannot be continuously circulated: it can only provide static cooling and cannot continuously and circulate the cooling energy to the external reaction equipment, which limits its application scenarios.

[0004] Reliant on manual labor and cumbersome operation: Experimenters need to frequently add dry ice to maintain the temperature, which is not only labor-intensive but also poses a risk of frostbite, making it difficult to automate and standardize the process.

[0005] 2. Commercial low-temperature circulating baths: These devices provide a relatively stable low-temperature environment through a built-in compressor refrigeration system. However, they also have a series of problems: The equipment is bulky and inconvenient to deploy: the presence of compressors and supporting systems results in large size and heavy weight of the equipment, making it difficult to move and requiring high standards for laboratory space layout.

[0006] Slow cooling rate: It usually takes a long time to cool from room temperature to the target low temperature (such as -70℃), which cannot meet the experimental requirements that require rapid cooling.

[0007] High purchase and maintenance costs: Precision refrigeration systems are expensive, and ongoing investment is required for maintenance and refrigerant replacement.

[0008] Low temperature limits are limited: the low temperature limits of conventional equipment are usually between -40°C and -80°C. To achieve even lower temperatures (such as -78°C with dry ice / ethanol bath), more complex and expensive systems are required.

[0009] 3. Complex Temperature Control Systems for Specialized Fields. Existing technologies also include temperature control systems designed to address specific extreme environments (such as deep-sea exploration), such as the "System for Actively Maintaining the Temperature of Sampling Cylinder Based on Alcohol-Dry Ice Cyclic Cooling" (CN120368675A). While these systems achieve active temperature control, their technical solutions are designed for extreme conditions such as high pressure, sealing, and pressure resistance in the deep sea. They incorporate a series of complex structures and control logics, including gear pumps, bladder pressure compensators, pressure relief valves, and complex predictive control algorithms based on BP neural networks. This solution is structurally complex and costly to manufacture. Furthermore, its core purpose is to address specific issues such as preventing phase changes in the medium and maintaining structural strength under high pressure. Its technical approach and system architecture are too complex and redundant for ordinary laboratory environments under normal pressure, lacking universality and economic viability.

[0010] In summary, there is an urgent need in this field for a new type of temperature control device that can balance low-temperature performance, temperature control accuracy, automation level, compact structure, and cost-effectiveness, in order to fill the market gap between traditional simple methods and modern complex systems. Utility Model Content

[0011] To address at least one of the aforementioned technical problems, this utility model provides a dry ice temperature control device, comprising a dry ice bucket, a pumping module, and a reaction tank. The dry ice bucket contains a heat exchange coil and is used to hold dry ice and a static heat transfer medium. The reaction tank holds circulating refrigerant. The pumping module includes a main pump and an auxiliary pump. The main pump is connected between the reaction tank and the inlet of the heat exchange coil and is used to drive the refrigerant circulation. The outlet of the heat exchange coil is connected to the reaction tank via a return pipe, on which a first solenoid valve is installed. The inlet of the auxiliary pump is connected via a branch pipe to the pipe section between the outlet of the heat exchange coil and the first solenoid valve, and the outlet of the auxiliary pump is connected to the reaction tank via a second solenoid valve. The device also includes a control unit, which is communicatively connected to the main pump, the auxiliary pump, the first solenoid valve, and the second solenoid valve.

[0012] In some implementations, the branch line is connected to the return line via a tee fitting.

[0013] In some implementations, the reaction vessel is an open-top container.

[0014] In some implementations, both the static heat transfer medium and the refrigerant are ethanol.

[0015] In some implementations, the top of the dry ice bucket is provided with a feeding port.

[0016] In some implementations, the main pump is a centrifugal pump and the auxiliary pump is a diaphragm pump.

[0017] In some implementations, the ends of the pipes connected to the reaction tank are all submerged below the surface of the refrigerant; the level of the static heat transfer medium in the dry ice bucket is not lower than the height of the heat exchange coil.

[0018] In some embodiments, the apparatus further includes a first temperature sensor disposed in the reaction tank and a second temperature sensor disposed in the dry ice bucket; the control unit is communicatively connected to the first temperature sensor and the second temperature sensor.

[0019] In some implementations, the control unit is configured to control the start / stop or speed of the main pump based on the detection value of the first temperature sensor.

[0020] In some implementations, the control unit is configured to perform one or all of the following modes: Fully automatic start mode: controls the second solenoid valve to open, the first solenoid valve to close, and starts the auxiliary pump; after a preset process, it switches to controlling the first solenoid valve to open, the second solenoid valve to close, and starts the main pump; Semi-automatic start mode: When the main pump inlet is full of liquid, the first solenoid valve is opened, the second solenoid valve is closed, and the main pump is started directly.

[0021] All materials used in this utility model are existing materials and do not involve new materials; all processes and methods used are existing technologies and do not involve new processes and methods.

[0022] Compared with the prior art, the beneficial effects of this utility model are mainly reflected in the following aspects: 1. Reliable Start-up and Stable Operation: Through a unique "dual-pump design" (combination of a diaphragm pump auxiliary pump and a centrifugal pump main pump) and automatic control logic, the system effectively solves the problems of "air binding" or difficulty in liquid aspiration caused by air in the pipeline during the startup of cryogenic equipment. The system can first use the self-priming capability of the diaphragm pump to complete the filling and emptying process, and then seamlessly switch to the centrifugal pump to provide a stable high-flow circulation, thus balancing the reliability of startup with the high efficiency and stability of operation.

[0023] 2. High temperature control accuracy: The device integrates multiple temperature sensors and, in conjunction with a control unit, adjusts the main pump at least twice its speed. By monitoring temperature feedback at key points, the main pump flow rate (i.e., refrigerant circulation speed) is adjusted in real time, thereby achieving precise control over the cooling rate and final temperature of the reaction tank, avoiding large temperature fluctuations.

[0024] 3. High system integration and compact structure: Through reasonable piping design and solenoid valve switching, the reuse and separation of the start-up circuit and the main circulation circuit are achieved using only simple tee connectors and branch lines. This design avoids complex and expensive dedicated equipment, making the entire device compact and cost-effective, and particularly suitable for use in laboratories and small-to-medium-scale production scenarios.

[0025] 4. High energy efficiency and safe operation: The dry ice bucket uses a static heat transfer medium (such as ethanol) and an immersion coil for heat exchange, which ensures a stable and efficient release of the cold energy of the dry ice and reduces the violent boiling and sudden change in cold energy caused by directly throwing dry ice.

[0026] Meanwhile, all pipe ends entering the reaction tank are submerged below the liquid surface. This not only prevents air from being drawn into the pump body, but also avoids temperature disturbances introduced by backflow liquid splashing, further improving the stability of temperature control and the safety of operation.

[0027] 5. Strong applicability and scalability: The control unit supports multiple start-up modes such as "fully automatic" and "semi-automatic", which can adapt to different operating habits and site conditions.

[0028] In summary, this utility model, through ingenious system design and intelligent control, comprehensively solves the core problems of miniaturized dry ice temperature control devices in terms of start-up reliability, operational stability, and temperature control accuracy without significantly increasing costs and complexity. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure and connection relationship of the dry ice temperature control device provided in Embodiment 1 of this utility model.

[0030] Attached reference numerals: 1-Dry ice bucket, 11-Heat exchange coil, 12-Feeding port, 2-Pumping module, 21-Main pump, 22-Auxiliary pump, 3-Reaction tank, 4-Control unit, V1-First solenoid valve, V2-Second solenoid valve, T-T-connector. Detailed Implementation

[0031] In order to make the technical means, inventive features, objectives and effects of the utility model easy to understand, the utility model is further described in conjunction with specific illustrations, but the utility model is not limited to the following embodiments.

[0032] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which this utility model can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0033] Terms such as “comprising” and “including” indicate that, in addition to the components that are directly and explicitly stated in the specification and claims, the technical solution of this utility model does not exclude the presence of other components that are not directly or explicitly stated.

[0034] This utility model provides a dry ice temperature control device and offers the following technical solution, which will be described in detail below with reference to the accompanying drawings: Example 1 like Figure 1 As shown, this embodiment provides a dry ice temperature control device, the core components of which include a dry ice bucket 1, a pumping module 2, and a reaction tank 3. The entire device is connected by pipelines and is uniformly coordinated and controlled by a control unit 4.

[0035] 1. Dry ice bucket assembly The dry ice bucket 1 is a standard container with an insulation layer. It has a feeding port (12) at the top for adding materials. A heat exchange coil 11 is fixedly installed inside the bucket; this coil can be made of stainless steel or copper, or other metals with good thermal conductivity. Before use, ethanol must be injected into the dry ice bucket 1 as a static heat transfer medium. The liquid level should not be lower than the top of the heat exchange coil 11 to ensure the coil is completely submerged and achieves sufficient heat exchange. Then, dry ice can be added in layers through the feeding port (12) to form a stable low-temperature cold source.

[0036] 2. Pumping module and reaction tank Pumping module 2 integrates main pump 21 and auxiliary pump 22. Main pump 21 is a centrifugal pump, characterized by its ability to provide a stable large flow rate at low temperatures; auxiliary pump 22 is a diaphragm pump, characterized by its good self-priming capability, enabling it to start drawing liquid from an empty pipe.

[0037] The reaction tank 3 is an open-top experimental container, which is an area that requires low-temperature control, and is filled with ethanol as a circulating refrigerant.

[0038] 3. Piping connections and circuit configuration The piping connections of the device are as follows: Main circulation loop: The main pump 21 is connected between the inlet of the heat exchange coil 11 of the reaction tank 3 and the dry ice bucket 1. The outlet of the heat exchange coil 11 is connected to the reaction tank 3 through a return pipeline, on which a first solenoid valve V1 is installed to switch the main loop on and off.

[0039] Start-up branch: The inlet end of the auxiliary pump 22 is connected via a branch pipeline to the pipe section between the outlet of the heat exchange coil 11 and the first solenoid valve V1. Preferably, the branch pipeline is connected to the return pipeline via a tee connector T. The outlet end of the auxiliary pump 22 is connected to the reaction tank 3 via the second solenoid valve V2.

[0040] Piping end location: A key structural feature is that the ends of all pipes connected to reaction tank 3 are submerged below the liquid level of the circulating refrigerant inside. This design ensures that both the main and auxiliary pumps can reliably draw in liquid, prevents air from entering the system, and allows the return liquid to smoothly integrate into the medium inside the tank, reducing splashing and temperature disturbances.

[0041] 4. Control and Monitoring System The control unit 4 is electrically connected to the main pump 21, the auxiliary pump 22, the first solenoid valve V1, and the second solenoid valve V2 via signal lines (only the control unit is shown in the attached figure, and the signal lines are omitted).

[0042] To further improve temperature control accuracy, the device is equipped with a temperature monitoring system. A first temperature sensor is installed inside the reaction tank 3 to monitor the temperature of the core reaction area; a second temperature sensor is installed inside the dry ice bucket 1 to monitor the status of the cold source; all these sensors are communicatively connected to the control unit 4.

[0043] Control unit 4 is configured to have multiple control capabilities: Speed ​​regulation: The control unit 4 can control the main pump 21 to switch between at least two speeds (such as high speed and low speed) according to the feedback signal of the first temperature sensor, so as to achieve different cooling intensities and perform precise temperature control.

[0044] Process Control: Control unit 4 can manage the system's startup process through output sequence control signals. In "fully automatic startup mode," control unit 4 first opens the second solenoid valve V2 and starts the auxiliary pump 22, using its self-priming capability to fill the entire pipeline system with liquid and remove air. After a preset running time, control unit 4 then opens the first solenoid valve V1, starts the main pump 21, and simultaneously closes the auxiliary pump 22 and the second solenoid valve V2, seamlessly switching the system to efficient and stable main circulation loop operation. In addition, control unit 4 also supports "semi-automatic startup mode." When the operator confirms that the pipeline is full of liquid, they can directly control the first solenoid valve V1 to open and start the main pump 21, skipping the self-priming step.

[0045] Specifically, the control unit (4) is configured to support two startup modes to cope with different initial conditions: (1) Fully automatic start mode: Suitable for the first liquid filling of the system or when there is air in the pipeline. After setting the target temperature and selecting this mode, the start command is triggered, and the control unit (4) will execute the following sequence: Open the second solenoid valve V2 and start the auxiliary pump 22. At this time, the first solenoid valve V1 is in the closed state.

[0046] The auxiliary pump 22 uses its self-priming capability to draw liquid from the reaction tank 3, which then flows through the main pump 21 and the heat exchange coil 11 in the dry ice bucket 1 before being drawn out and returned to the reaction tank 3 through a branch pipeline. This process lasts for about tens of seconds and is intended to fill the entire pipeline system with liquid and remove air.

[0047] After the filling is completed, the control unit 4 opens the first solenoid valve V1 and starts the main pump 21 for a short time, while closing the auxiliary pump 22 and the second solenoid valve V2.

[0048] The system then seamlessly switched to the main circulation loop driven by the main pump 21 and entered a stable working state.

[0049] (2) Semi-automatic start mode: Applicable when the inlet of the main pump 21 is already full of liquid (e.g., system restart). In this mode, after the operator confirms that the conditions are met, the control unit 4 responds to the start command, directly opens the first solenoid valve V1 and starts the main pump 21, while keeping the auxiliary pump 22 closed and the second solenoid valve V2 closed, and the equipment immediately enters the normal pumping state.

[0050] The temperature control logic is as follows: After the system enters the main circulation, the control unit 4 dynamically adjusts the speed of the main pump 21 based on the difference between the temperature (T1) monitored by the first temperature sensor of the reaction tank and the preset target temperature (T) to achieve precise temperature control. Intensive cooling stage: When T1 > T and the temperature difference is greater than 10℃, the control unit 4 controls the main pump 21 to run at high speed and provide the maximum flow rate to quickly send the high-temperature liquid in the reaction tank to the dry ice bucket for cooling, thereby achieving rapid cooling.

[0051] Precise approach phase: When T1 approaches the target temperature (e.g., the temperature difference is within 10°C), the control unit 4 switches the main pump 21 to low-speed operation to slow down the cooling rate and prevent temperature overshoot.

[0052] Intermittent heat preservation stage: When T1 reaches the target temperature T, the control unit 4 controls the main pump 21 to stop running. Subsequently, if the temperature of the reaction tank naturally rises due to heat load, when T1 > T and the temperature difference exceeds 1℃, the control unit 4 will restart the main pump 21 to run intermittently at low speed, circulating a small amount of refrigerant to offset the heat input, thereby stabilizing the temperature within the target range for a long period of time.

[0053] The working principle of this utility model is briefly described as follows: First, the system is filled with liquid via auxiliary pump 22. Then, in main circulation mode, control unit 4 switches to start main pump 21 and opens the first solenoid valve V1. The heated circulating refrigerant (ethanol) in reaction tank 3 is drawn out by main pump 21 and pumped into the heat exchange coil 11 of dry ice tank 1. Inside the coil, the circulating refrigerant undergoes efficient heat exchange with the dry ice / ethanol mixture at approximately -78°C inside the tank, and is rapidly cooled. The cooled refrigerant flows out of the dry ice tank and returns to reaction tank 3 through branch pipelines to cool the materials inside. This cycle repeats continuously. Combined with feedback from the temperature sensor and speed regulation of main pump 21 by control unit 4, rapid temperature reduction and long-term precise stability within reaction tank 3 can be achieved.

[0054] This utility model has a compact structure and cleverly combines the self-priming advantage of diaphragm pumps with the stable and large flow rate advantage of centrifugal pumps through a unique dual-pump dual-circuit design. It also solves the problem of balancing startup and operation of miniaturized cryogenic devices by using a simple solenoid valve switching logic. It is particularly suitable for laboratory and small-to-medium-scale production scenarios.

[0055] The preferred embodiments of this utility model have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of this utility model without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of this utility model through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A dry ice temperature control device, comprising a dry ice bucket (1), a pumping module (2), and a reaction tank (3), characterized in that: The dry ice bucket (1) is equipped with a heat exchange coil (11) inside, which is used to contain dry ice and static heat transfer medium; The pumping module (2) includes a main pump (21) and an auxiliary pump (22). The reaction tank (3) is used to contain circulating refrigerant; The main pump (21) is connected between the reaction tank (3) and the inlet of the heat exchange coil (11) to drive the refrigerant circulation; the outlet of the heat exchange coil (11) is connected to the reaction tank (3) through a return pipeline, and a first solenoid valve (V1) is provided on the return pipeline. The inlet end of the auxiliary pump (22) is connected to the pipe section between the outlet of the heat exchange coil (11) and the first solenoid valve (V1) through a branch pipe, and the outlet end of the auxiliary pump (22) is connected to the reaction tank (3) through the second solenoid valve (V2). The device also includes a control unit (4), which is communicatively connected to the main pump (21), the auxiliary pump (22), the first solenoid valve (V1), and the second solenoid valve (V2).

2. The dry ice temperature control device according to claim 1, characterized in that, The branch line is connected to the return line via a T-joint.

3. The dry ice temperature control device according to claim 1, characterized in that, The reaction tank (3) is an open container.

4. The dry ice temperature control device according to claim 1, characterized in that, Both the static heat transfer medium and the refrigerant are ethanol.

5. The dry ice temperature control device according to claim 1, characterized in that, The top of the dry ice bucket (1) is provided with a feeding port (12).

6. The dry ice temperature control device according to claim 1, characterized in that, The main pump (21) is a centrifugal pump, and the auxiliary pump (22) is a diaphragm pump.

7. The dry ice temperature control device according to claim 1, characterized in that, The ends of the pipes connected to the reaction tank (3) are all submerged below the liquid surface of the refrigerant; the liquid level of the static heat transfer medium in the dry ice bucket (1) is not lower than the height of the heat exchange coil (11).

8. The dry ice temperature control device according to claim 1, characterized in that, It also includes a first temperature sensor installed in the reaction tank (3) and a second temperature sensor installed in the dry ice bucket (1); the control unit (4) is communicatively connected to the first temperature sensor and the second temperature sensor.

9. The dry ice temperature control device according to claim 8, characterized in that, The control unit (4) is configured to control the start / stop or speed of the main pump (21) based on the detection value of the first temperature sensor.

10. The dry ice temperature control device according to claim 1, characterized in that, The control unit (4) is configured to perform one or all of the following modes: Fully automatic start mode: control the second solenoid valve (V2) to open, the first solenoid valve (V1) to close, and start the auxiliary pump (22); after a preset process, switch to control the first solenoid valve (V1) to open, the second solenoid valve (V2) to close, and start the main pump (21). Semi-automatic start mode: When the inlet of the main pump (21) is filled with liquid, the first solenoid valve (V1) is opened, the second solenoid valve (V2) is closed, and the main pump (21) is started directly.

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