Low-temperature device

Abstract

According to the low-temperature device provided by the invention, the first heat exchanger and the second heat exchanger are connected in series in the flowing path of the refrigerant by utilizing the characteristics that the refrigerating effect of the refrigerant is gradually reduced and the requirements of the first heat exchanger and the second heat exchanger on the refrigerant are different, and the cavity of the second heat exchanger forms an effect similar to a cold shield; the first heat exchanger and the second heat exchanger can be roughly cooled synchronously, heat exchange between the first heat exchanger and the external environment can be effectively weakened or even isolated in the cooling process, the cooling capacity of refrigerants can be fully utilized, and heat exchange between devices in the heat exchange assembly and the external environment can be automatically weakened in time along with the cooling process. And the cooling efficiency is greatly improved, so that the cooling capacity of the refrigerant is fully utilized.

Description

Technical Field

[0001] This invention belongs to the field of measurement and testing technology, and relates to the adjustment of the temperature of the sample being tested, specifically to a low-temperature device. Background Technology

[0002] A cryostat is a device that can cool or maintain a sample or component under test at a low temperature. It provides the necessary temperature conditions for testing the sample at low temperatures and is a key component in equipment involving the detection of low-temperature and superconducting states.

[0003] Most existing cryogenic thermostats achieve cooling of the sample by using refrigerant to flow and exchange heat near the object being cooled. For example, CN112825278B describes a cryogenic thermostat structure and magnetic resonance imaging device for magnetic resonance imaging. In this device, a refrigerant container is placed inside a chamber, and a superconducting coil is housed within the container by immersing it in liquid refrigerant to cool and maintain its low temperature. However, in practice, the refrigerant typically enters a recovery or release path after flowing past the object being cooled, wasting its remaining cooling capacity and resulting in insufficient utilization of the refrigerant's cooling capacity, thus affecting its efficiency.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of the present invention, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] To improve the efficiency of refrigerant cooling utilization in cryogenic constant temperature applications, this invention provides a cryogenic device, comprising a heat exchange assembly, a sample rod, a sample cooling shield, and a housing. The heat exchange assembly includes a first heat exchanger and a second heat exchanger, with refrigerant channels of the first and second heat exchangers connected in series. The refrigerant passes sequentially through the first and second heat exchangers. The second heat exchanger is configured as a cavity, and the first heat exchanger is disposed inside the cavity of the second heat exchanger. The sample rod is connected to the first heat exchanger, passes through the second heat exchanger, and extends outward from the second heat exchanger. The sample cooling shield is connected to the second heat exchanger and fitted over the sample rod. The housing is fitted over the heat exchange assembly and the sample cooling shield, and the interior of the housing is a vacuum environment.

[0006] Preferably, the refrigerant flows between the first heat exchanger and the second heat exchanger through a pipeline, and the pipeline between the first heat exchanger and the second heat exchanger is located within the cavity of the second heat exchanger.

[0007] Preferably, the first heat exchanger has an internal cavity, and at least one of the heater and the temperature sensor is disposed in the internal cavity of the first heat exchanger. The heater is directly or indirectly thermally connected to the sample rod.

[0008] More preferably, a heater and a temperature sensor are disposed in the cavity inside the first heat exchanger, with the temperature sensor close to the sample rod and the heater away from the sample rod.

[0009] Preferably, the sample rod is provided with at least one of a heater and a temperature sensor.

[0010] Preferably, the housing and the sample cooling screen are each provided with a transparent and closed observation window, which is generally positioned opposite the position where the sample rod carries the sample.

[0011] Preferably, the heat exchange component is spaced apart from the housing, and the heat exchange component is fixedly connected to the housing.

[0012] Preferably, the first heat exchanger and the second heat exchanger are spaced apart, and the first heat exchanger and the second heat exchanger are fixedly connected.

[0013] More preferably, a connecting member is provided between the first heat exchanger and the second heat exchanger, the connecting member is fixed inside the cavity of the second heat exchanger, and the first heat exchanger is fixedly connected to the connecting member.

[0014] In a further preferred embodiment, two connectors are provided, and the two connectors are respectively fixedly connected to the two ends of the first heat exchanger in one direction.

[0015] Preferably, the housing is provided with a connecting pipe, and a pipe for conveying refrigerant that passes through at least the heat exchange component is provided inside the connecting pipe, and the connecting pipe is provided on the side away from the sample rod.

[0016] The present invention has at least the following beneficial effects: by utilizing the gradual decrease in the cooling effect of the refrigerant and the difference in refrigerant demand between the first and second heat exchangers, the first and second heat exchangers are connected in series in the refrigerant flow path, and the cavity of the second heat exchanger forms a cold screen-like effect. This allows the first and second heat exchangers to cool down substantially synchronously. At the same time, during the cooling process, the heat exchange between the first heat exchanger and the external environment can be effectively reduced or even isolated. This not only makes full use of the cooling capacity of the refrigerant, but also automatically and timely reduces the heat exchange between the internal devices of the heat exchange components and the external environment during the cooling process, greatly improving the cooling efficiency and making full use of the cooling capacity of the refrigerant. Attached Figure Description

[0017] Figure 1This is a schematic diagram of the external shape of one embodiment of the present invention; Figure 2 This is a schematic diagram of a heat exchange assembly and a sample cooling screen according to one embodiment of the present invention; Figure 3 A schematic diagram of the inner side of a heat exchange assembly according to one embodiment of the present invention; Figure 4 A schematic diagram of a first heat exchanger according to one embodiment of the present invention; Figure 5 This is a schematic diagram of a sample rod and related components according to one embodiment of the present invention. Detailed Implementation

[0018] To make the objectives and features of the present invention more apparent and understandable, the specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that the drawings are all in a very simplified form and use non-precise ratios, and are only used to conveniently and clearly assist in illustrating the objectives of the embodiments of the present invention.

[0019] This invention provides a cryogenic device, including a heat exchange assembly, a sample rod 400, a sample cooling shield 500, and a housing 100. The heat exchange assembly includes a first heat exchanger 300 and a second heat exchanger 200, with refrigerant channels of the first heat exchanger 300 and the second heat exchanger 200 connected in series, allowing the refrigerant to pass through the first heat exchanger 300 and the second heat exchanger 200 sequentially. The second heat exchanger 200 is configured as a cavity, with the first heat exchanger 300 disposed inside the cavity of the second heat exchanger 200. The sample rod 400 is connected to the first heat exchanger 300, thus the first heat exchanger 300 can utilize the cooling effect of the refrigerant to lower the temperature of the sample rod 400. The sample rod 400 passes through the second heat exchanger 200 and extends outward from the second heat exchanger 200, thereby reducing the space requirement of the sample rod 400 during use. The sample cooling screen 500 is connected to the second heat exchanger 200 and is fitted over the sample rod 400. The temperature of the second heat exchanger 200 is used to cool the sample cooling screen 500, and the sample cooling screen 500 is used to isolate the sample rod 400 from the external environment. The housing 100 is fitted over the heat exchange assembly and the sample cooling screen 500. The housing 100 is a vacuum environment, which further reduces the heat transfer between the heat exchange assembly, the cooling screen assembly 500 and the external environment.

[0020] The refrigerant first undergoes a first heat exchange in the first heat exchanger 300, and then enters the second heat exchanger 200 for a second heat exchange. In some cases, the cooling effect of the refrigerant generally decreases gradually after multiple heat exchanges. That is to say, the refrigerant in the first heat exchanger 300 has the best cooling effect, while the refrigerant in the second heat exchanger 200 has a slightly lower cooling effect compared to the first heat exchanger 300. Correspondingly, when the refrigerant is used for sufficient heat exchange, the temperature of the first heat exchanger 300 is the lowest, and the temperature of the second heat exchanger 200 is relatively slightly higher. Correspondingly, the temperature of the sample rod 400 connected to the first heat exchanger 300 is lower, while the temperature of the sample cooling screen 500 connected to the second heat exchanger 200 is slightly higher than that of the sample rod 400 (but still at a relatively low temperature). In operation, when refrigerant is introduced for cooling, the refrigerant flows through the first heat exchanger 300 and then the second heat exchanger 200. From the cooling process perspective, the first heat exchanger 300 and the second heat exchanger 200 begin cooling approximately simultaneously, with the second heat exchanger 200 cooling slightly less than the first heat exchanger 300. The cavity of the second heat exchanger 200 forms a shape similar to a cold screen to reduce heat exchange between the first heat exchanger 300 and the external environment of the second heat exchanger 200. Even though the cooling of the second heat exchanger 200 is slightly less than that of the first heat exchanger 300, the second heat exchanger 200... This configuration is sufficient to reduce or even isolate the heat exchange between the first heat exchanger 300 and the external environment. In other words, the arrangement of the first heat exchanger 300 and the second heat exchanger 200 provided by this invention utilizes the cooling characteristics of the refrigerant, enabling the first heat exchanger 300 and the second heat exchanger 200 to cool down substantially synchronously. Simultaneously, during the cooling process, it effectively reduces or even isolates the heat exchange between the first heat exchanger 300 and the external environment. This fully utilizes the cooling capacity of the refrigerant and automatically and timely reduces the heat exchange between the internal components of the heat exchange assembly and the external environment during the cooling process, significantly improving cooling efficiency. Correspondingly, the cooling relationship between the sample rod 400 and the sample cold shield 500 is similar to that of the first heat exchanger 300 and the second heat exchanger 200. It also fully utilizes the cooling capacity of the refrigerant and automatically and timely reduces the heat exchange between the sample rod 300 and the external environment of the sample cold shield 500 during the cooling process, significantly improving the cooling efficiency of the sample rod 400. Furthermore, by creating a vacuum environment inside the housing 100, the heat exchange between the sample rod 400, the sample cold shield 500, the heat exchange assembly and the external environment of the housing 100 is further reduced, so that the sample rod 300, the sample cold shield 500 and the heat exchange assembly can be cooled down quickly and maintained at a lower temperature, thereby reducing the consumption of refrigerant.At low temperature, the refrigerant consumes relatively little cooling capacity in the first heat exchanger 300 to keep the sample rod 400 at a low temperature. The remaining cooling capacity is transferred to the second heat exchanger 200 to reduce the heat exchange between the first heat exchanger 300, the sample rod 400 and external equipment. The overall demand of the low temperature device on the cooling capacity carried by the refrigerant is reduced, thus reducing the amount of refrigerant required to maintain the low temperature.

[0021] The refrigerant flows between the first heat exchanger 300 and the second heat exchanger 200 through piping. The piping between the first heat exchanger 300 and the second heat exchanger 200 is located within the cavity of the second heat exchanger 200. Please refer to [link / reference]. Figure 4 This diagram illustrates a refrigerant piping configuration, wherein a first heat exchanger 300 is provided with a refrigerant inlet 322 and a refrigerant outlet 323, and a second heat exchanger 200 is provided with a refrigerant inlet 232 and a refrigerant outlet 233. A refrigerant inlet pipe 610 is connected to the refrigerant inlet 322 of the first heat exchanger 300, allowing the refrigerant to enter the first heat exchanger 300 from the outside. The refrigerant flows in the first heat exchanger 300, causing the temperature of the first heat exchanger 300 to decrease and the temperature of the refrigerant to increase slightly. Subsequently, the refrigerant flows out from the refrigerant outlet 323 of the first heat exchanger 300 and flows through pipe 630 to... The refrigerant enters the second heat exchanger 200 through the refrigerant inlet 232; the refrigerant flows in the second heat exchanger 200 to lower its temperature. Since the refrigerant temperature in the second heat exchanger 200 is slightly higher than that in the first heat exchanger 300, the degree of cooling in the second heat exchanger 200 is slightly less than that in the first heat exchanger 300 in some cases. According to the arrangement of the invention, this difference in the degree of cooling is acceptable; the refrigerant then flows out of the second heat exchanger 200 through the refrigerant outlet 233 and flows out of the device through the output pipe 620. It should be noted that the pipe 630 is at least partially located within the cavity of the second heat exchanger 200. The refrigerant flowing through the pipe 630 also generates a cooling effect. Therefore, placing the pipe 630 within the cavity of the second heat exchanger 200 can lower the temperature within the cavity, further ensuring a low-temperature environment for the first heat exchanger 300 and improving the utilization efficiency of the refrigerant's cooling capacity. Of course, in some cases, the pipe 630 can also be placed in other locations within the cavity of the second heat exchanger 200, such as on the cavity wall or the outer side of the cavity.

[0022] Please see Figure 2 , Figure 3The second heat exchanger 200 includes a heat exchange plate 230, a heat insulation cavity 220, and caps 221 and 222. The heat exchange plate 230 is connected to one end of the heat insulation cavity 220. Cap 221 closes the other end opening of the heat insulation cavity 220. Cap 222 is connected to the heat exchange plate 230 to close the other end opening of the assembly of the heat insulation cavity 220 and the heat exchange plate 230. A through hole for the sample rod 400 to extend is provided on the side of the heat insulation cavity 220. A sample cooling screen 500 is fitted over the sample rod 400 and connected to the side of the heat insulation cavity 220 to close the through hole for the sample rod 400 to extend. The heat exchange plate 230, heat insulation cavity 220, caps 221 and 222, and sample... The cold shield 500 forms a cavity to accommodate the first heat exchanger 300 and the sample rod 400. The refrigerant flowing out of the first heat exchanger 300 enters the interior of the second heat exchanger 200 through the refrigerant inlet 232 provided on the second heat exchanger 200. The refrigerant flows inside the heat exchanger 200 to exchange heat fully. Then, the refrigerant flows out of the second heat exchanger 200 through the refrigerant outlet 233 provided on the second heat exchanger 200. The low temperature of the second heat exchanger 200 reduces the temperature of components such as the heat insulation cavity 220, the sample cold shield 500, and the caps 221 and 222. In other words, it reduces the temperature of the cavity structure where the first heat exchanger 300 is located. In some cases, the cavity of the second heat exchanger 200 can be provided with an opening 224 to accommodate the refrigerant pipes 610 and 620. The opening 224 can connect the cavity of the second heat exchanger 200 and its corresponding components with the cavity of the outer shell 100. The cavity of the second heat exchanger 200 and its corresponding components is a vacuum environment. By utilizing the vacuum environment, the heat transfer between the first heat exchanger, the sample rod and the second heat exchanger is further reduced.

[0023] Please see Figure 3 The first heat exchanger 300 has a cavity 321 inside, and at least one of the heater 330 and the temperature sensor 340 is disposed in the cavity 321 inside the first heat exchanger 300. Figure 3 A feasible structure of a first heat exchanger 300 is shown, wherein the first heat exchanger 300 is provided with a body 320 in which refrigerant flows for heat exchange. A heater 330 is directly or indirectly thermally connected to a sample rod 400. Specifically, the heater 330 can be directly connected to the sample rod 430, or the heater 330 can be connected to the first heat exchanger 300, which in turn connects to the sample rod 400, thus achieving an indirect thermal connection between the heater 330 and the sample rod 400. This invention... Figure 3 This paper presents a technical solution for an indirect thermal connection between the heater 330 and the sample rod 400. It is understood that the thermal connection method between the heater 330 and the sample rod 400 can be adjusted according to actual needs, which will not be elaborated here.

[0024] A temperature sensor 420 is arranged at the sample rod near the sample-bearing position 410, which makes the temperature data obtained by the temperature sensor 420 closer to the temperature of the sample-bearing position 410, and thus closer to the temperature of the sample carried on the sample rod 400.

[0025] It is understandable that during the cooling process of the sample rod 400, the temperature of the sample rod 400 is reduced under the action of the first heat exchanger 300. During the cooling process, the cooling process of the sample rod 400 and the first heat exchanger 300 is roughly similar. When the preset cooling range is reached, the temperatures of the sample rod 400 and the first heat exchanger 300 stabilize within the preset range. The temperature of the first heat exchanger 300 can be detected by the temperature sensor 340 to at least determine the temperature of the first heat exchanger 340. In some cases, the temperature of the sample rod 400 can also be inferred from the data measured by the temperature sensor 340.

[0026] Please see Figure 3 In some cases, multiple heaters 330 may be provided, for example, two heaters 330 may be provided. In this case, the heaters 330 can be symmetrically arranged along the length of the sample rod 400, so that the heat transfer from the heaters 330 to the sample rod 400 via the first heat exchanger 300 is more even. Please refer to [link / reference]. Figure 5 Alternatively, a heater 430 can be installed on the sample rod 400 to directly heat the sample rod 400.

[0027] Please see Figure 5 In some cases, a temperature sensor 420 can be installed on the sample rod 400 to more accurately measure the temperature of the sample rod 400. Of course, in order to facilitate the estimation of the temperature of the analyte carried by the sample rod 400 by measuring the temperature of the sample rod 400, the temperature sensor 420 can be placed near the position 410 on the sample rod 400 where the sample is carried.

[0028] In some cases, a heater 430 and a temperature sensor 420 can be installed on the sample rod 400 simultaneously to more accurately measure and adjust the temperature of the sample rod 400 and the test object it carries.

[0029] Please see Figure 1 , 2 4. The housing 100 and the sample cooling screen 500 are respectively provided with transparent and closed observation windows 111 and 510, which are roughly opposite to the sample rod 400 at the sample-bearing position 410. It is understood that the observation windows 111 and 510 do not need to be perfectly aligned with the sample rod 400 at the sample-bearing position 410, as long as the sample can be observed from outside the device through the observation windows 111 and 510.

[0030] Please see Figure 3 , Figure 4 The sample rod 400 is provided with a sample-bearing position 410. Specifically, in some cases, the sample-bearing position 410 is provided with a sample stage, and the sample is fixed on the sample stage. In addition, when it is necessary to test the sample involving electrical signals, the sample stage may also be provided with a pin plate or electrical contacts or a structure that enables the sample to be electrically connected to the corresponding components of the sample rod 400, so that the sample can communicate with the electrical signal transmitting and receiving equipment via the sample rod 400, thereby realizing the testing of the sample involving electrical signals at low temperature.

[0031] The heat exchange component is spaced apart from the housing 100 and fixedly connected to it. By substantially separating the heat exchange component from the housing 100, heat transfer between them is reduced, further decreasing the heat transfer efficiency between the heat exchange component and the external environment of the housing 100. This improves the cooling efficiency of the heat exchange component and reduces the amount of refrigerant required to maintain its low temperature. More specifically, the aforementioned fixed connection between the heat exchange component and the housing 100 can be achieved through a thermal insulation component. For example, please refer to... Figure 2 The heat exchange assembly is fixedly connected to the housing 100 through the heat insulation column 240. More specifically, as a feasible method, when the second heat exchanger 200 is located outside the first heat exchanger 300, one end of the heat insulation column 240 can be connected to the second heat exchanger 200 and the other end can be connected to the housing 100. By setting multiple heat insulation columns 240, the connection between the heat exchange assembly and the housing 100 can be made reliable.

[0032] When the heat insulation column 240 is provided and connected to the second heat exchanger 200, the covers 221 and 222 of the second heat exchanger 200 are provided with corresponding avoidance structures so that the heat insulation column 240 can be directly connected to the second heat exchanger 200 and the shell 100.

[0033] Please see Figure 3 , Figure 4The first heat exchanger 300 and the second heat exchanger 200 are spaced apart and fixedly connected, thereby reducing the heat transfer efficiency between them. More specifically, as a feasible implementation, connectors 350 and 360 are provided between the first heat exchanger 300 and the second heat exchanger 200. Connectors 350 and 360 are fixed inside the cavity of the second heat exchanger 200, and the first heat exchanger 300 is fixedly connected to the connectors 350 and 360, so that there is no direct contact between them. This allows the heat transfer efficiency between the first heat exchanger 300 and the second heat exchanger 200 to be adjusted by using connectors 350 and 360. For example, connectors 350 and 360 made of insulating material can be used to further reduce the heat transfer efficiency between the first heat exchanger 300 and the second heat exchanger 200. Please refer to [link to relevant documentation]. Figure 5 This illustrates a feasible connection method between the first heat exchanger 300 and the connectors 350 and 360. Two connectors 350 and 360 are provided, each fixedly connected to one end of the first heat exchanger 300 in one direction. This makes the first heat exchanger 300 more securely fixed, thus reducing the impact of vibrations caused by refrigerant entering and exiting the cryogenic device on the heat exchange assembly, thereby reducing or isolating vibrations of the sample rod 400 and the sample it supports. As a feasible method, the first heat exchanger 300 can be generally cylindrical, with the two connectors 350 and 360 fixedly connected to both ends of the first heat exchanger 300, and the sample rod 400 disposed on the circumferential surface of the first heat exchanger 300. Furthermore, in some cases, a heat insulation component can be provided between the first heat exchanger 300 and the connectors 350 and 360, for example, the connection between the first heat exchanger 300 and the connectors 350 and 360 can be achieved through a heat insulation column 370. For connectors 350 and 360, since connectors 350 and 360 are located in the cavity of the second heat exchanger 200 along with the first heat exchanger 300, connectors 350 and 360 can be provided with corresponding cutouts 351 and 361 as needed, which can further reduce heat leakage while meeting the fixing requirements of the first heat exchanger 300.

[0034] Please see Figure 1 The housing 100 is provided with a connecting pipe 130. Pipes 610 and 620 for conveying refrigerant through at least the heat exchange components are disposed inside the connecting pipe 130, which is located on the side away from the sample rod 400. In some embodiments, the connecting pipe 130 may be further extended and connected to corresponding equipment, such as refrigerant driving equipment or vacuum equipment, which will not be described in detail here.

[0035] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Therefore, the above descriptions are merely embodiments of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the present invention. Various equivalent changes and modifications are included without departing from the spirit and scope of the present invention, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A cryogenic device, characterized in that: The device includes a heat exchange assembly, a sample rod, a sample cold shield, and a housing. The heat exchange assembly includes a first heat exchanger and a second heat exchanger. The refrigerant channels of the first heat exchanger and the second heat exchanger are connected in series. The refrigerant passes through the first heat exchanger and the second heat exchanger in sequence. The second heat exchanger is constructed in the form of a cavity. The first heat exchanger is disposed inside the cavity of the second heat exchanger. The sample rod is connected to the first heat exchanger, the sample rod passes through the second heat exchanger and extends outward from the second heat exchanger, and the sample cold shield is connected to the second heat exchanger and sleeved on the outside of the sample rod; The housing is fitted over the heat exchange assembly and the sample cooling screen, and the interior of the housing is a vacuum environment.

2. The cryogenic device as described in claim 1, characterized in that: The refrigerant flows between the first heat exchanger and the second heat exchanger through a pipeline, and the pipeline between the first heat exchanger and the second heat exchanger is located inside the cavity of the second heat exchanger.

3. The cryogenic device as described in claim 1, characterized in that: The first heat exchanger has an internal cavity, and at least one of the heater and the temperature sensor is disposed in the internal cavity of the first heat exchanger. The heater is directly or indirectly thermally connected to the sample rod.

4. The cryogenic device as described in claim 1, characterized in that: The sample rod is equipped with at least one of a heater and a temperature sensor.

5. A cryogenic device as described in claim 1, characterized in that: The housing and the sample cooling screen are each provided with a transparent and closed observation window, which is generally positioned opposite the position where the sample rod carries the sample.

6. The cryogenic device as described in claim 1, characterized in that: The heat exchange component is spaced apart from the housing, and the heat exchange component is fixedly connected to the housing.

7. The cryogenic device as described in claim 1, characterized in that: The first heat exchanger and the second heat exchanger are spaced apart and are fixedly connected.

8. The cryogenic device as described in claim 7, characterized in that: A connecting member is provided between the first heat exchanger and the second heat exchanger. The connecting member is fixed inside the cavity of the second heat exchanger, and the first heat exchanger is fixedly connected to the connecting member.

9. A cryogenic device as described in claim 8, characterized in that: Two connectors are provided, and the two connectors are fixedly connected to the two ends of the first heat exchanger in one direction.

10. A cryogenic device as described in claim 1, characterized in that: The housing is provided with a connecting pipe, and a pipe for conveying refrigerant that passes through at least the heat exchange component is provided inside the connecting pipe, which is located on the side away from the sample rod.

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