Liquefied gas storage system

Abstract

This invention provides a liquefied gas preservation system that can stably preserve cells contained in a cell preservation container by maintaining the environment inside the container. [Solution] The liquefied gas storage system includes a cell storage container for storing the contained cells at a low temperature while maintaining the volume of the supplied liquefied gas.

Description

Technical Field

[0001] The present invention relates to a system for storing liquefied gas.

Background Art

[0002] A system for supplying liquid nitrogen is known (for example, Patent Document 1, etc.). In this system, a storage tank installed outdoors and a container are always connected, and liquid nitrogen is directly supplied from the storage tank to the container.

[0003] Also, another system for supplying liquid nitrogen is known (for example, Patent Document 2, etc.). In this system, a liquefied gas storage tank 1 installed outdoors and a liquefied gas container 3 for cryopreserving biological samples are always connected, and liquid nitrogen is directly supplied from the liquefied gas storage tank 1 to the liquefied gas container 3.

[0004] Furthermore, a device in which a primary dewar 1412 storing liquid nitrogen and a secondary dewar 1414 are mounted on a wheeled cart together with other devices is also known (for example, Patent Document 3, etc.).

[0005] Furthermore, a supply system in which a storage tank 1 and a treatment tank 6 are connected and liquefied dimethyl ether 2 is supplied from the storage tank 1 to the treatment tank 6 is known (for example, Patent Document 4, etc.). In this system, the amount of liquefied dimethyl ether 2 supplied into the treatment tank 6 could not be obtained.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

[0007] The systems described in Patent Documents 1 and 2 inevitably required long liquid nitrogen supply paths, and furthermore, the installation locations of the systems were limited. As a result, it was often difficult to maintain the environment inside the container to which the liquid nitrogen was supplied, or to adjust the configuration for maintaining the environment inside the container.

[0008] The apparatus described in Patent Document 3 was prone to vibration and shock during operations such as replacing the primary dewar 1412 and secondary dewar 1414. These vibrations and shocks were transmitted throughout the wheeled cart, making it difficult to maintain the environment inside the containers placed on the cart.

[0009] The supply system described in Patent Document 4 simply supplies liquefied dimethyl ether 2 to the processing tank 6, and it was not possible to obtain the amount of liquefied dimethyl ether 2 supplied into the processing tank 6. Therefore, it was not possible to determine whether or not the environment inside the processing tank 6 was being maintained.

[0010] The present invention has been made in view of the above-mentioned points. Its objective is to provide a liquefied gas preservation system that can stably preserve objects contained in a cell preservation container by maintaining the environment inside the cell preservation container. [Means for solving the problem]

[0011] The features of the liquefied gas storage system according to the present invention are: The system includes a cell preservation container for maintaining the volume of the supplied liquefied gas while preserving the contained cells at a low temperature. [Effects of the Invention]

[0012] Maintaining the environment within the cell storage container allows for the stable preservation of cells contained within the container. [Brief explanation of the drawing]

[0013] [Figure 1] It is a block diagram showing the configuration of the liquefied gas storage system according to this embodiment. [Figure 2] It is a schematic diagram showing the configuration of the cell storage container 100. [Figure 3] It is a schematic diagram (FIG. 3A) showing the configuration of the cell storage container 100 using the liquid level sensor 200 and a schematic diagram (FIG. 3B) showing the configuration of the cell storage container 100 using the weight sensor 250. [Figure 4] It is a perspective view showing the configuration of the fluid pump 300 having two first electrodes 310-1 and a second electrode 310-2. [Figure 5] It is an enlarged plan view (FIG. 5A) showing the details of the arrangement of the two first electrodes 310-1 and the second electrode 310-2 of the fluid pump 300 and an enlarged cross-sectional view (FIG. 5B) showing the cross-section taken along the arrow A-A in FIG. 4. [Figure 6] It is a flowchart showing the process of maintaining the capacity of liquid nitrogen. [Figure 7] It is a time chart showing the operating state of the fluid pump 300. [Figure 8] It is a flowchart showing the process of notifying the remaining amount of liquid nitrogen. [Figure 9] It is a flowchart showing the process of notifying an abnormal consumption amount of liquid nitrogen. [Figure 10] It is a flowchart showing the process for switching from liquid-phase storage to gas-phase storage. [Figure 11] It is a flowchart showing the process for switching from gas-phase storage to liquid-phase storage.

Mode for Carrying Out the Invention

[0014] <<<<Summary of This Embodiment>>>> <<First Feature>> According to the first feature, A liquefied gas storage system is provided that includes a cell storage container (e.g., cell storage container 100 described below) for storing the contained cells at a low temperature while maintaining the bulk of the supplied liquefied gas.

[0015] The cell storage container is a container for storing the contained cells at a low temperature. The bulk of the liquefied gas supplied to the cell storage container is maintained.

[0016] By maintaining the bulk of the liquefied gas supplied to the cell storage container, the storage environment of the cells can be maintained. Bulk refers to the height or size of stacked items. Also, bulk generally refers to the quantity of an aggregate. In the case of a liquid, bulk may include volume, capacity, weight, etc., as well as the liquid level. Bulk may be anything that indicates the size of the area occupied by the entire object.

[0017] The liquefied gas may be any refrigerant that can stably cool the cells. For example, the liquefied gas can use an inert gas such as liquid nitrogen, liquid helium, or liquefied argon. Also, the liquefied gas preferably has a configuration supplied from a liquefied gas tank. The liquefied gas tank may be fixed or portable. Any configuration that can supply liquefied gas to the liquefied gas storage system is acceptable.

[0018] <<Second Feature>> The second feature is as follows in the first feature. A bulk detection unit (e.g., liquid level sensor 200 or weight sensor 250 described below) for detecting the bulk of the liquefied gas supplied to the cell storage container, and a bulk adjustment unit (e.g., fluid pump 300 described below) for adjusting the bulk of the liquefied gas when the detected bulk of the liquefied gas exceeds a predetermined range.

[0019] The liquefied gas storage system further comprises a volume detection unit and a volume adjustment unit. The volume detection unit detects the volume of liquefied gas supplied to the cell storage container. The volume adjustment unit adjusts the volume of liquefied gas when the volume of liquefied gas detected by the volume detection unit exceeds a predetermined range. The volume adjustment unit adjusts the volume of liquefied gas by increasing the amount of liquefied gas if the volume is less than the predetermined range, and by decreasing the amount of liquefied gas if the volume is more than the predetermined range.

[0020] The liquefied gas in the cell storage container can be maintained at the desired volume, thereby preserving the cell storage environment.

[0021] <<Third characteristic>> The third characteristic is that, in the first or second characteristic, The aforementioned height adjustment section is A supply operation in which liquefied gas is supplied from a liquefied gas tank to the cell storage container, A discharge operation to discharge liquefied gas from the cell storage container, This can be executed selectively.

[0022] The volume adjustment unit selectively performs supply and discharge operations. The supply operation is the operation of supplying liquefied gas from the liquefied gas tank to the cell storage container. The discharge operation is the operation of discharging liquefied gas from the cell storage container.

[0023] The supply operation allows for the replenishment of liquefied gas from the liquefied gas tank into the cell storage container. This replenishment of liquefied gas helps maintain a stable cell storage environment. Furthermore, the supply operation allows for a smooth transition from gas-phase to liquid-phase cell storage.

[0024] The discharge operation simply involves discharging the liquefied gas from the cell storage container; there is no need to return the liquefied gas to the liquefied gas tank. However, the system may be configured to return the liquefied gas discharged from the cell storage container to the liquefied gas tank. A solenoid valve or similar device may be provided to allow or prevent the return of liquefied gas to the liquefied gas tank as needed. The discharge operation allows for a smooth transition from liquid-phase to gas-phase storage of cells.

[0025] <<Fourth characteristic>> The fourth characteristic is that, in the first to third characteristics, The system further includes a control unit that determines whether the volume of the detected liquefied gas falls within the predetermined range.

[0026] The control unit's decision-making process allows the detected volume of liquefied gas to be kept within a predetermined range.

[0027] <<The fifth characteristic>> The fifth characteristic is that, in the first through fourth characteristics, The liquefied gas tank and the cell storage container are further provided with an on / off valve (for example, solenoid valves 600a, 600b, 600c, etc., described later), The control unit outputs an open command or a close command to the on / off valve.

[0028] By closing the on / off valve, the supply of liquefied gas from the liquefied gas tank can be shut off. In this way, even if vibration or shock occurs during the liquefied gas tank replacement work, the liquefied gas will not flow rapidly into the cell storage container, thus preventing the effects of the replacement work from affecting the cell storage container and preventing abrupt changes in the cell storage environment inside the cell storage container.

[0029] <<Feature #6>> The sixth characteristic is that, in the first through fifth characteristics, It also features a movable mounting platform, At least the cell storage container and the volume detection unit are placed on the aforementioned stand.

[0030] Since the cell storage container and the bulk detection unit are mounted on a stand, they can be moved simultaneously, making it easy to adjust their positions and improving usability. Furthermore, because the cell storage container and bulk detection unit can be integrated into a single unit, miniaturization is easier.

[0031] The control unit, as well as the cell storage containers and volume detection unit, may be mounted on the mounting platform. This allows for further integration. However, it is preferable not to mount the liquefied gas tank on the mounting platform. By not mounting the liquefied gas tank on the mounting platform, vibrations and shocks that occur during the replacement of the liquefied gas tank can be prevented from being transmitted to the cell storage containers.

[0032] <<Characteristic 7>> The seventh characteristic is that, in the first through sixth characteristics, The height adjustment unit operates in at least one of periodic or non-periodic operation.

[0033] By making the volume adjustment unit operate in a periodic or non-periodic manner, the preferred operation can be selected according to the type and size of the cells.

[0034] <<Feature #8>> The eighth characteristic is, in the first through seventh characteristics, The height adjustment unit, which operates in a non-periodic motion, has a non-movable member. The aforementioned non-movable member displaces the liquefied gas.

[0035] Because it has no moving parts, it can operate stably and accurately even at low temperatures. Furthermore, since the liquefied gas is displaced by non-moving parts and not by moving parts, it does not generate vibrations or pulsations, allowing cells to be stored in a quiet storage environment.

[0036] <<Characteristic 9>> The ninth feature is, in the first through eighth features, The control unit, The volume adjustment unit stores the amount of liquefied gas supplied from the liquefied gas tank to the cell storage container. From the supply amount, at least one of the remaining amount in the liquefied gas tank and the replacement time for the liquefied gas tank is calculated. Based on the remaining amount or replacement time, information regarding the liquefied gas tank is output.

[0037] As liquefied gas is supplied from the liquefied gas tank to the cell storage containers, the amount of liquefied gas in the tank gradually decreases. When the amount of liquefied gas remaining in the tank falls to a certain level, the tank needs to be replaced.

[0038] The cumulative supply amount can be calculated by adding the amount of liquefied gas supplied to the cell storage containers. When the cumulative supply amount exceeds a predetermined value, it indicates that the remaining amount of liquefied gas in the liquefied gas tank is low, and a notification can be issued that it is time to replace the liquefied gas tank. This notification ensures that liquefied gas is supplied to the cell storage containers without interruption, providing a stable storage environment.

[0039] <<Feature #10>> The tenth feature is, in the first through tenth features, The control unit, Information regarding the consumption of liquefied gas in the cell storage container is output based on the difference between a first timing when the volume adjustment unit stops supplying liquefied gas to the cell storage container and a second timing when the volume adjustment unit first starts supplying liquefied gas to the cell storage container after the first timing.

[0040] The time between the first instance of stopping the supply of liquefied gas and the second instance of starting the supply of liquefied gas is usually approximately constant. However, if leaks occur in the cell storage container or supply system due to changes in the sealing state over time, the time between the first and second instances tends to shorten. By monitoring the time between the first and second instances, changes in the sealing state, such as leaks, can be detected early, and the storage environment can be maintained.

[0041] <<<<Details of this embodiment>>>> The embodiments will be described below with reference to the drawings.

[0042] <<<Liquefied Gas Storage System 10>>> Figure 1 is a block diagram showing the configuration of the liquefied gas storage system 10 according to this embodiment. Figure 2 is a schematic diagram showing the configuration of the cell storage container 100. Figure 3 is a schematic diagram (Figure 3A) showing the configuration of the cell storage container 100 using a liquid level sensor 200, and a schematic diagram (Figure 3B) showing the configuration of the cell storage container 100 using a weight sensor 250.

[0043] The liquefied gas storage system 10 mainly comprises a cell storage container 100, a liquid level sensor 200, a fluid pump 300, a control unit 400, a liquid nitrogen tank 500, pipes 550a, 550b, 550c, solenoid valves 600a, 600b, 600c, a used tank 700, and a movable stand 800.

[0044] <<Cell storage container 100>> The cell storage container 100 has a lower part 110 and an upper part 150.

[0045] <Bottom of container 110> The lower part of the container 110 has a roughly cylindrical shape, and the upper part of the container 150 has a roughly conical shape. The lower part 110 and the upper part of the container 150 share a common central axis O (see Figures 2 and 3).

[0046] The lower part of the container 110 has a bottom surface 112 and side surfaces 114. The bottom surface 112 and side surfaces 114 have an insulating material (not shown). The insulating material allows cells to be stored stably at low temperatures. The bottom surface 112 is located at the very bottom of the lower part of the container 110. The bottom surface 112 has a substantially circular shape. The side surfaces 114 are provided on the bottom surface 112 perpendicular to it.

[0047] <Opening 120 for liquid nitrogen> The side portion 114 has a liquid nitrogen opening 120 near the bottom portion 112. Liquid nitrogen is injected into or discharged from the cell storage container 100 through the liquid nitrogen opening 120.

[0048] <Container top 150> The upper part 150 of the container tapers towards the top. The upper part 150 has an opening 152 at its uppermost end. The opening 152 has a roughly circular shape. A liquid level sensor 200 can be inserted into and removed through the opening 152. Cell holding members 180, such as canes or boxes for cryopreserving cells, can be inserted into and removed through the opening 152. By using cell holding members 180, such as canes or boxes, cells can be held in a fixed position in the cell storage container 100 and cryopreserved. Liquid nitrogen can be injected or discharged through the liquid nitrogen opening 120, but it may also be injected or discharged through the opening 152.

[0049] The opening 152 is smaller than the bottom surface 112. This helps to suppress the evaporation of liquid nitrogen.

[0050] <Lid 170> The lid 170 seals the opening 152. A liquid level sensor 200 can be detachably mounted on the lid 170. Cell holding members 180, such as canes or boxes, can also be detachably mounted on the lid 170 (Figure 2). Alternatively, other members or jigs may be prepared separately from the lid 170 to hold the cell holding members 180, such as canes or boxes, in a fixed position on the cell storage container 100.

[0051] The overall shape of the cell storage container 100 is not limited to this. The cell storage container 100 only needs to be able to hold liquid nitrogen and stably freeze and store cells.

[0052] <<Liquid level sensor 200>> The liquid level sensor 200 has a sensor unit 210 and an interface unit 220 (see Figure 3A).

[0053] The sensor unit 210 is electrically connected to the interface unit 220. The interface unit 220 is held in a fixed position within the cover 170. The sensor unit 210 has an elongated shape. The sensor unit 210 extends from the interface unit 220.

[0054] When the lid 170 is attached to the opening 152, the interface portion 220 is positioned inside the cell storage container 100. When the lid 170 is attached to the opening 152, the interface portion 220 extends along the central axis O, and at least a portion of it is immersed in the liquid nitrogen contained in the cell storage container 100. When the lid 170 is attached to the opening 152, the sensor portion 210 extends in a direction perpendicular to the liquid level LV, i.e., parallel to the side portion 114.

[0055] The liquid level sensor 200 detects the liquid nitrogen level LV by capacitance generated between the sensor unit 210 and the side unit 114. When the liquid nitrogen level LV changes, the capacitance between the sensor unit 210 and the side unit 114 changes. The liquid level sensor 200 can continuously detect the liquid nitrogen level LV. The interface unit 220 outputs a detection signal indicating the detected liquid level LV. The liquid level sensor 200 is electrically connected to the control unit 400. The detection signal is output to the control unit 400.

[0056] <Sensor for detecting the volume of liquid nitrogen> Instead of the liquid level sensor 200, another sensor that detects the volume of liquid nitrogen may be used.

[0057] <Weight Sensor 250> For example, a weight sensor 250 may be used instead of the liquid level sensor 200 (see Figure 3B).

[0058] The weight sensor 250 detects the weight of the liquid in the cell storage container 100. The weight sensor 250 is installed on the mounting platform 260 on which the cell storage container 100 is placed. In this case, the cell storage container 100 is detachably mounted on the mounting platform 260. The weight sensor 250 outputs a detection signal indicating the weight of the cell storage container 100 and the liquid nitrogen placed on the mounting platform 260. By subtracting the weight of the cell storage container 100 through calibration processing, only the weight of the liquid nitrogen can be obtained and processed as the volume or liquid level of the liquid nitrogen.

[0059] <Level switch> Alternatively, a level switch may be used instead of the liquid level sensor 200 or the weight sensor 250 (not shown).

[0060] The level switch has a float that displaces vertically in response to changes in the liquid level. When the float reaches the uppermost position within the level switch, an electrical connection is formed, and when the float is in any other position, the electrical connection is released. When an electrical connection is formed, a detection signal is output from the level switch.

[0061] Multiple level switches are arranged spaced apart from each other along a direction perpendicular to the liquid level LV. Multiple level switches are arranged along the central axis O of the cell storage container 100. That is, level switches are provided at multiple different positions along the central axis O. A detection signal is emitted from each level switch according to the liquid level LV. The liquid level LV of the liquid nitrogen can be obtained by the number of detection signals output from the level switches. By arranging multiple level switches along the central axis O of the cell storage container 100, the liquid level LV of the liquid nitrogen can be detected discretely.

[0062] <Other detection methods> Furthermore, sensors using other detection methods may be used instead of the liquid level sensor 200, weight sensor 250, and level switch (not shown). For example, an optical sensor may be used to detect the presence or absence of liquid nitrogen and process it as the volume of liquid nitrogen or the liquid level LV.

[0063] <<Fluid Pump 300>> Figure 4 is a perspective view showing the configuration of a fluid pump 300 having two first electrodes 310-1 and a second electrode 310-2. Figure 5 is an enlarged plan view (Figure 5A) showing details of the arrangement of the two first electrodes 310-1 and the second electrode 310-2 of the fluid pump 300, and an enlarged cross-sectional view (Figure 5B) showing the cross-section indicated by arrow AA in Figure 4.

[0064] The fluid pump 300 has two first electrodes 310-1 and a second electrode 310-2. The fluid pump 300 has a housing 320 of a predetermined size. The entirety of the two first electrodes 310-1 and the second electrode 310-2 is housed within the housing 320 and immersed in a fluid such as liquid nitrogen.

[0065] <Enclosure 320> The housing 320 has a fixed, elongated, roughly rectangular cylindrical shape. The cross-section of the housing 320 perpendicular to the longitudinal direction (the upstream and downstream direction of fluids such as liquid nitrogen) (the horizontal direction shown in Figure 4) is a rectangle of a fixed size. The housing 320 has two ends in the longitudinal direction. One end of the housing 320 has a first opening 332. The other end of the housing 320 has a second opening 334. The housing 320 has an elongated through hole 336 along its longitudinal direction. The first opening 332 and the second opening 334 face each other with the through hole 336 in between. The housing 320 communicates with the through hole 336 from the first opening 332 to the second opening 334. The through hole 336 defines an elongated flow path along its longitudinal direction. Liquid nitrogen can flow along the longitudinal direction of the through hole 336.

[0066] The first opening 332 is connected to pipe 550b, and the second opening 334 is connected to pipe 550c (see Figure 1). The housing 320 is made of a material through which a fluid such as liquid nitrogen can flow. The housing 320 has an insulating member (not shown). The housing 320 has a bottom surface 340 along its longitudinal direction. The bottom surface 340 has a flat, elongated rectangular shape.

[0067] <First electrode 310-1 and second electrode 310-2> The first electrode 310-1 and the second electrode 310-2 are made of a conductive material. The first electrode 310-1 and the second electrode 310-2 are made of a material that does not deteriorate or change in quality even when directly exposed to liquid nitrogen. The first electrode 310-1 and the second electrode 310-2 are made of linear members having a cross-section of a certain size and shape. The first electrode 310-1 and the second electrode 310-2 have the same configuration, the same size and the same shape.

[0068] The first electrode 310-1 and the second electrode 310-2 have a generally comb-like shape. The first electrode 310-1 and the second electrode 310-2 extend along the bottom surface 340. The first electrode 310-1 and the second electrode 310-2 are provided within the through hole 336. The first electrode 310-1 and the second electrode 310-2 are positioned between the first opening 332 and the second opening 334.

[0069] The first electrode 310-1 and the second electrode 310-2 each have a long, linearly extending support portion 312. The support portions 312 of the first electrode 310-1 and the second electrode 310-2 are arranged along the longitudinal direction of the housing 320. The support portions 312 extend along the longitudinal direction of the through hole 336 between the first opening 332 and the second opening 334.

[0070] The first electrode 310-1 and the second electrode 310-2 each have a plurality of linear electrodes 314 that extend parallel to each other and spaced apart. The plurality of linear electrodes 314 extend perpendicularly from the support portion 312. The plurality of linear electrodes 314 are arranged perpendicular to the longitudinal direction of the housing 320. The support portion 312 and the plurality of linear electrodes 314 are electrically connected. The support portion 312 and the plurality of linear electrodes 314 are at the same potential. Two adjacent linear electrodes 314 of the first electrode 310-1 and two adjacent linear electrodes 314 of the second electrode 310-2 each have a constant interval D0. The plurality of linear electrodes 314 of the first electrode 310-1 and the plurality of linear electrodes 314 of the second electrode 310-2 are each arranged in parallel at constant intervals D0.

[0071] The multiple linear electrodes 314 are of the same length. Each of the multiple linear electrodes 314 has a first end 316 and a second end 318. The first end 316 is fixedly attached to the support 312. Each of the multiple linear electrodes 314 is electrically connected to the support 312 at the first end 316. The second end 318 is the end furthest from the support 312.

[0072] The lengths of the multiple linear electrodes 314 and the spacing between two adjacent linear electrodes 314 can be appropriately determined according to the potential applied to the first electrode 310-1 and the second electrode 310-2. The thickness and cross-sectional shape of the linear members constituting the first electrode 310-1 and the second electrode 310-2 can also be appropriately determined according to the potential applied to the first electrode 310-1 and the second electrode 310-2.

[0073] <Arrangement of the first electrode 310-1 and the second electrode 310-2> The entirety of the first electrode 310-1 and the second electrode 310-2 extends parallel to the bottom surface 340. As shown in Figures 4 and 5A, the support portion 312 of the first electrode 310-1 and the support portion 312 of the second electrode 310-2 are arranged parallel to each other and spaced apart along the bottom surface 340. The longitudinal directions of the support portion 312 of the first electrode 310-1 and the support portion 312 of the second electrode 310-2 are aligned with the longitudinal direction of the bottom surface 340.

[0074] As shown in Figure 5A, the second ends 318 of the multiple linear electrodes 314 of the first electrode 310-1 are positioned toward the support portion 312 of the second electrode 310-2. The second ends 318 of the multiple linear electrodes 314 of the first electrode 310-1 are spaced apart from the support portion 312 of the second electrode 310-2.

[0075] Similarly, the second ends 318 of the multiple linear electrodes 314 of the second electrode 310-2 are positioned toward the support portion 312 of the first electrode 310-1. The second ends 318 of the multiple linear electrodes 314 of the second electrode 310-2 are spaced apart from the support portion 312 of the first electrode 310-1.

[0076] As shown in Figure 4, the power supply unit 350 is electrically connected to each of the two first electrodes 310-1 and the second electrode 310-2. In the example shown in Figure 4, a positive power supply voltage (+V1) is applied to the first electrode 310-1, and a negative power supply voltage (-V2) lower than +V1 is applied to the second electrode 310-2. As a result, the linear electrode 314 of the first electrode 310-1 is at a potential of (+V1), and the linear electrode 314 of the second electrode 310-2 is at a lower potential (-V2) than the linear electrode 314 of the first electrode 310-1 (see Figure 5B). In this way, an electric field can be generated between the linear electrode 314 of the first electrode 310-1 and the linear electrode 314 of the second electrode 310-2 in a direction along the longitudinal direction of the housing 320. The potential of the linear electrode 314 of the first electrode 310-1 and the potential of the linear electrode 314 of the second electrode 310-2 can be appropriately determined according to the type of fluid to be flowed and the desired flow velocity.

[0077] <<Formation of electric fields of different magnitudes>> As shown in Figures 5A and 5B, there are two types of spacing between the linear electrodes 314 of adjacent first electrodes 310-1 and second electrodes 310-2: a short spacing D1 and a long spacing D2. The short spacing D1 and the long spacing D2 are alternately repeated along the longitudinal direction of the housing 320.

[0078] A strong jet stream can be generated by the short gap D1 between the linear electrode 314 of the first electrode 310-1 and the linear electrode 314 of the second electrode 310-2. In other words, a pair of electrodes that generate a strong jet stream is formed by the linear electrode 314 of the first electrode 310-1 and the linear electrode 314 of the second electrode 310-2 separated by a narrow gap D1. By arranging pairs of electrodes at regular intervals D0 along the longitudinal direction of the housing 320, it is possible to easily generate a strong jet stream.

[0079] However, interference between these pairs of electrodes can cause backflow of the jet stream. Therefore, by providing a wide gap D2 between the single linear electrode 314 of the first electrode 310-1 and the single linear electrode 314 of the second electrode 310-2, backflow of the jet stream can be prevented, ensuring that the fluid flows in one direction and allows the fluid to flow smoothly.

[0080] <<Power supply 350>> In the example shown in Figure 4, the power supply unit 350 supplies a DC voltage separately to each of the two first electrodes 310-1 and the second electrode 310-2. The power supply unit 350 supplies a DC voltage of a constant value that does not change over time. In this way, a static electrostatic field and electric field lines that do not change over time are generated from each of the linear electrodes 314 of the first electrode 310-1 and the linear electrode 314 of the second electrode 310-2.

[0081] In the following, we will first operate the fluid pump 300 so that the fluid flows from the left side (upstream) to the right side (downstream), as shown by the white arrow in Figure 4.

[0082] A power supply voltage of either positive or negative polarity is applied to the first electrode 310-1, and a power supply voltage of a different polarity from that of the first electrode 310-1 is applied to the second electrode 310-2. The polarity of the power supply voltage applied to each of the first electrode 310-1 and the second electrode 310-2 is determined by the fluid composition, etc. The polarity of the power supply voltage is set so that the fluid flows from the left side (upstream) to the right side (downstream) in Figure 4, and the fluid pump 300 is operated.

[0083] Specifically, when a positive power supply voltage is applied to the first electrode 310-1, a negative power supply voltage is applied to the second electrode 310-2. Conversely, when a negative power supply voltage is applied to the first electrode 310-1, a positive power supply voltage is applied to the second electrode 310-2. By determining the polarity of the power supply voltage according to the fluid's components, the fluid can be made to flow from the left side (upstream) to the right side (downstream) in Figure 4, regardless of the type of liquid.

[0084] The spacings D1 and D2 should be determined appropriately depending on the type of fluid and the desired flow velocity.

[0085] Furthermore, even if the power supply voltages applied to the first electrodes 310-1 and 310-2 have the same polarity, it is sufficient that the power supply voltage applied to the first electrode 310-1 is different from the power supply voltage applied to the second electrode 310-2.

[0086] Furthermore, instead of a DC power supply voltage, a pulsating power supply voltage, such as a pulsed power supply voltage, may be applied to at least one of the first electrodes 310-1 and 310-2. The timing of application, pulse period, and voltage value to the first electrode 310-1 and the second electrode 310-2 should be appropriately determined according to the type of fluid, the desired fluid flow rate, and the output of the fluid pump 300.

[0087] Up to this point, we have shown an example of operating the power supply unit 350 to flow a fluid from left to right in Figure 4, regardless of the type of liquid.

[0088] In contrast, for a fluid having the same components, the direction of fluid flow can be reversed by reversing the polarity of the power supply voltage applied to the first electrode 310-1 and the second electrode 310-2.

[0089] For example, applying a positive power supply voltage to the first electrode 310-1 and a negative power supply voltage to the second electrode 310-2 allows the fluid to flow from the left (upstream) to the right (downstream) in Figure 4. However, applying a positive power supply voltage to the second electrode 310-2 and a negative power supply voltage to the first electrode 310-1 allows the fluid to flow from the right (upstream) to the left (downstream) in Figure 4.

[0090] Furthermore, by applying a negative power supply voltage to the first electrode 310-1 and a positive power supply voltage to the second electrode 310-2, the fluid can flow from the left (upstream) to the right (downstream) in Figure 4. Similarly, by applying a negative power supply voltage to the second electrode 310-2 and a positive power supply voltage to the first electrode 310-1, the fluid can flow from the right (upstream) to the left (downstream) in Figure 4.

[0091] In this way, for fluids having the same components, the direction of the fluid flow can be reversed by changing the polarity of the power supply voltage. For example, one direction of flow can be used to supply liquid nitrogen to the cell storage container 100, and the opposite direction of flow can be used to discharge liquid nitrogen from the cell storage container 100. Thus, the fluid pump 300 can be used for both supplying (supplying operation) and discharging (discharging operation) liquid nitrogen.

[0092] The control unit 400 outputs an operating control signal to the fluid pump 300. The power supply unit 350 outputs the polarity and power supply voltage indicated by the operating control signal to the two first electrodes 310-1 and the second electrode 310-2. This allows a fluid such as liquid nitrogen to flow in the desired direction and at the desired flow rate.

[0093] The fluid pump 300 has no moving parts and is resistant to deterioration over time, even when immersed in liquids such as liquid nitrogen or in low-temperature conditions, and can maintain the desired operation.

[0094] <<Control Unit 400>> The control unit 400 controls various devices such as the fluid pump 300 and solenoid valves 600a, 600b, and 600c by performing various calculations, data processing, and decision processing based on the detection signal emitted from the liquid level sensor 200.

[0095] For example, the control unit 400 receives detection signals emitted from the liquid level sensor 200 at predetermined intervals. The control unit 400 also outputs an operation control signal to the fluid pump 300 to control the operating state of the fluid pump 300. Furthermore, the control unit 400 outputs open / close control signals to the solenoid valves 600a, 600b, and 600c to control the open / closed state of the solenoid valves 600a, 600b, and 600c.

[0096] The control unit 400 mainly includes a processor (such as a CPU (Central Processing Unit)), ROM (Read-Only Memory), RAM (Random Access Memory), I / F (Interface Device), auxiliary storage devices (such as HDD (Hard Disk Drive) or SSD (Solid State Drive)), input devices (such as a keyboard, mouse, or touch panel), a display, a speaker, etc. (not shown). For example, the control unit 400 can be a PLC (Programmable Logic Controller), a personal computer, a tablet computer, a portable terminal device, or a similar device. The ROM and RAM store programs for the flowcharts shown in Figures 6 and 8-11, which will be described later, as well as data used for these programs. Various information can be output from the display and speaker to inform the operator.

[0097] The control unit 400 transmits control signals to various devices such as the fluid pump 300 and solenoid valves 600a, 600b, and 600c via an interface device (I / F).

[0098] <<Liquid Nitrogen Tank 500>> The liquid nitrogen tank 500 is a dedicated liquid extraction container suitable for replenishing liquefied gas, etc. The liquid nitrogen tank 500 has an on / off valve 510 (see Figure 1). The liquid nitrogen tank 500 has a roughly cylindrical shape. The liquid nitrogen tank 500 has casters 520 (see Figure 1). The casters 520 allow the liquid nitrogen tank 500 to be moved, facilitating the replacement of the liquid nitrogen tank 500. Liquid nitrogen is supplied from the liquid nitrogen tank 500 to the cell storage container 100 according to the operating state of the fluid pump 300 and the open / closed states of the solenoid valves 600a, 600b, and 600c.

[0099] <<Pipe 550a, 550b, 550c, 550d, 550e>> Pipes 550a to 550e are long, flexible, sealing, and heat insulating. Pipes 550a to 550e have a long, hollow space along their longitudinal direction. Pipes 550a to 550e guide liquid nitrogen along their longitudinal direction.

[0100] Pipe 550a connects the liquid nitrogen tank 500 and the solenoid valve 600a so that they can communicate with each other. Pipe 550a allows liquid nitrogen to flow between the liquid nitrogen tank 500 and the solenoid valve 600a.

[0101] Pipe 550b connects the solenoid valve 600c and the fluid pump 300 in a manner that allows them to communicate. Pipe 550b allows liquid nitrogen to flow between the solenoid valve 600c and the fluid pump 300.

[0102] The tube 550c connects the fluid pump 300 and the cell storage container 100 so that they can communicate with each other. The tube 550c allows liquid nitrogen to flow between the fluid pump 300 and the cell storage container 100.

[0103] Pipe 550d connects the solenoid valve 600b and the spent tank 700 in a way that allows them to communicate. Pipe 550d allows liquid nitrogen to flow between the solenoid valve 600b and the spent tank 700.

[0104] Pipe 550e connects solenoid valves 600a, 600b, and 600c in a manner that allows them to communicate with each other. Pipe 550e allows liquid nitrogen to flow between solenoid valves 600a, 600b, and 600c.

[0105] <<Solenoid valves 600a, 600b, 600c>> The solenoid valves 600a, 600b, and 600c switch their open / closed state according to the open / closed control signal output from the control unit 400, changing the communication state to the following first to third states.

[0106] The first state (supply state) is a state in which liquid nitrogen can be supplied by opening solenoid valves 600a and 600c and closing solenoid valve 600b, thereby connecting the liquid nitrogen tank 500 and the fluid pump 300. By opening solenoid valves 600a and 600c and operating the fluid pump 300 in supply mode, liquid nitrogen can be guided from the liquid nitrogen tank 500 to the cell storage container 100.

[0107] The second state (discharge state) is a state in which liquid nitrogen can be guided by opening solenoid valves 600b and 600c and closing solenoid valve 600a, thereby connecting the fluid pump 300 to the used tank 700. By opening solenoid valves 600b and 600c and operating the fluid pump 300 in discharge mode, liquid nitrogen can be discharged from the cell storage container 100 to the used tank 700.

[0108] The third state (shut-off state) involves closing all solenoid valves 600a, 600b, and 600c, thereby shutting off communication between the liquid nitrogen tank 500 and the fluid pump 300, as well as communication between the fluid pump 300 and the used tank 700. By entering the third state, liquid nitrogen cannot flow through solenoid valves 600a, 600b, and 600c. For example, during the replacement of the liquid nitrogen tank 500, this prevents liquid nitrogen from flowing into or out of the cell storage container 100, thus preventing abrupt changes in the cell storage environment.

[0109] <<Used Tank 700>> When switching the cell preservation state from liquid phase to gas phase, the solenoid valves 600a, 600b, and 600c are set to the second state, and the fluid pump 300 is activated to discharge liquid nitrogen from the cell preservation container 100 to the used tank 700. This reduces the amount of liquid nitrogen in the cell preservation container 100 to the amount required for gas phase preservation.

[0110] Furthermore, since the liquid nitrogen is discharged into the used tank 700 and not returned to the liquid nitrogen tank 500, even if the liquid nitrogen in the cell storage container 100 becomes contaminated, it will not mix with the liquid nitrogen stored in the liquid nitrogen tank 500, thus preventing contamination of the liquid nitrogen in the liquid nitrogen tank 500.

[0111] Furthermore, the system may be configured to resupply the cell storage container 100 with the liquid nitrogen that has been discharged into the used tank 700, if necessary. This allows for the conservation of liquid nitrogen. The used tank 700 is preferably a tank with thermal insulation properties.

[0112] <<Movable stand 800>> The cell storage container 100 and the fluid pump 300 are placed on a movable platform 800, connected by a pipe 550c. The movable platform 800 has casters 810. The movable platform 800 allows the positions of the cell storage container 100 and the fluid pump 300 to be changed simultaneously. The cell storage container 100 and the fluid pump 300 can be moved together to the desired position. Using the movable platform 800 makes the moving process easier and more user-friendly. Furthermore, not only the cell storage container 100 and the fluid pump 300, but also the control unit 400 and other components may be placed on the movable platform 800.

[0113] Furthermore, it is preferable not to place the liquid nitrogen tank 500 on the movable stand 800. By not placing the liquid nitrogen tank 500 on the movable stand 800, even if vibrations or shocks occur during work such as replacing the liquid nitrogen tank 500, it is possible to prevent these vibrations or shocks from being transmitted to the cell storage container 100, thereby preventing any impact on the cell storage environment.

[0114] <<<Liquid nitrogen volume maintenance treatment>>> Figure 6 is a flowchart showing the process for maintaining the volume of liquid nitrogen in the cell storage container 100. This process is called and executed by the control unit 400 at predetermined intervals (for example, by interrupt processing). By performing this process, the volume of liquid nitrogen can be constantly monitored.

[0115] <Liquid phase lower limit LL, liquid phase upper limit LU, gas phase lower limit VL, gas phase upper limit VU> The process shown in Figure 6 can be used whether the cells are stored in the liquid phase or the gas phase. When storing in the liquid phase, use the lower limit LL of the liquid phase in step S611 and the upper limit LU of the liquid phase in step S617. When storing in the gas phase, use the lower limit VL of the gas phase in step S611 and the upper limit VU of the gas phase in step S617.

[0116] Liquid-phase storage requires a larger amount of liquid nitrogen than gas-phase storage. Therefore, as shown in Figure 2, the lower limit LL and upper limit LU of the liquid phase are located above the lower limit VL and upper limit VU of the gas phase. In liquid-phase storage, even if the liquid nitrogen level changes, it is sufficient that all cell storage containers 100 holding the cells remain immersed in the liquid nitrogen. On the other hand, in gas-phase storage, changes in the liquid nitrogen level may affect the temperature of the gas phase. Therefore, it is preferable that the difference between the upper limit VU and the lower limit VL of the gas phase be less than or equal to the difference between the upper limit LU and the lower limit LL of the liquid phase. That is, it is preferable to set the values ​​such that upper limit VU - lower limit VL ≤ upper limit LU - lower limit LL of the liquid phase.

[0117] In the process shown in Figure 6, first, the processor of the control unit 400 determines whether the liquid level value indicated by the detection signal emitted from the liquid level sensor 200 is below the lower limit (step S611).

[0118] When the processor of the control unit 400 determines that the liquid level is below the lower limit (YES), it outputs an operation control signal to the fluid pump 300 indicating the start of pump operation (step S613). As a result, the fluid pump 300 starts operating in supply mode, and liquid nitrogen is supplied from the liquid nitrogen tank 500 to the cell storage container 100.

[0119] Next, the processor of the control unit 400 stores the time when the fluid pump 300 started operating as the start time (step S615).

[0120] After executing the process in step S615, or if the processor of the control unit 400 determines in the decision process of step S611 that the liquid level is not below the lower limit (NO), it determines whether the liquid level indicated by the detection signal emitted from the liquid level sensor 200 is above the upper limit (step S617).

[0121] When the processor of the control unit 400 determines that the liquid level is above the upper limit (YES), it outputs an operation control signal to the fluid pump 300 indicating that the pump should be stopped (step S619). As a result, the fluid pump 300 stops operating, and the supply of liquid nitrogen to the cell storage container 100 is stopped.

[0122] Next, the processor of the control unit 400 stores the time when the fluid pump 300 stopped as the stop time (step S621).

[0123] Next, the processor of the control unit 400 stores the difference between the start time stored in step S615 and the stop time stored in step S615 as the pump operating time (step S623).

[0124] Next, the processor of the control unit 400 calculates and stores the supply amount by multiplying the supply amount per unit time by the pump operating time stored in step S623 (step S625). The supply amount per unit time can be obtained by operating the fluid pump 300 in advance and measuring it beforehand. For example, the power supply voltage supplied to each of the two first electrodes 310-1 and the second electrode 310-2 of the fluid pump 300 and the flow rate generated at that time are measured, and the correspondence between various power supply voltages and flow rates is stored in a table format or interpolation formula. In the processing of step S625, the supply amount per unit time can be obtained by referring to this correspondence.

[0125] Next, the processor of the control unit 400 reads the supply amount stored in step S625 from RAM and adds it to calculate and store the cumulative supply amount (step S627). Each time the liquid nitrogen volume maintenance process shown in Figure 6 is called and the process in step S625 is executed, the supply amount is calculated and stored. In this way, each time liquid nitrogen is supplied to the cell storage container 100, the supplied amount can be stored successively. The cumulative supply amount can be calculated by reading the previously stored supply amounts from RAM and adding them.

[0126] <Operating status of fluid pump 300> Figure 7 is a time chart showing the operating state of the fluid pump 300. In the example shown in Figure 7, at time t1, the fluid pump 300 is activated to start supplying liquid nitrogen from the liquid nitrogen tank 500 (steps S613 and S615 in Figure 6), and at time t2, the fluid pump 300 is stopped to stop supplying liquid nitrogen (steps S619 and S621 in Figure 6).

[0127] After time t2, there is a period of time during which the fluid pump 300 is not operated. At time t3, the fluid pump 300 is operated again to start supplying liquid nitrogen from the liquid nitrogen tank 500 (steps S613 and S615 in Figure 6). At time t4, the fluid pump 300 is stopped to stop supplying liquid nitrogen (steps S619 and S621 in Figure 6).

[0128] Furthermore, after a period of time when the fluid pump 300 is not operated, at time t5 the fluid pump 300 is operated again to start supplying liquid nitrogen from the liquid nitrogen tank 500 (steps S613 and S615 in Figure 6), and at time t6 the fluid pump 300 is stopped to stop supplying liquid nitrogen (steps S619 and S621 in Figure 6).

[0129] Furthermore, after a period of time when the fluid pump 300 is not operated, at time t7 the fluid pump 300 is operated again to start supplying liquid nitrogen from the liquid nitrogen tank 500 (steps S613 and S615 in Figure 6), and at time t8 the fluid pump 300 is stopped to stop supplying liquid nitrogen (steps S619 and S621 in Figure 6).

[0130] In the example shown in Figure 7, The amount of liquid nitrogen supplied between time t1 and time t2, The amount of liquid nitrogen supplied between time t3 and time t4, The amount of liquid nitrogen supplied between time t5 and time t6, The amount of liquid nitrogen supplied between time t7 and time t8, The amount obtained by adding this is the cumulative supply.

[0131] Furthermore, when the liquid nitrogen tank 500 is replaced, the cumulative supply amount can be reset, allowing for the proper calculation of the cumulative supply amount after the replacement of the liquid nitrogen tank 500.

[0132] In the liquid nitrogen volume maintenance process shown in Figure 6, after executing the process in step S627, the processor of the control unit 400 calculates and stores the pump non-operating time (step S629). The pump non-operating time is the difference between the time when the operation of the fluid pump 300 is stopped and the time when the operation of the fluid pump 300 is started again.

[0133] In the example shown in Figure 7, The time from time t2 to time t3, The time from time t4 to time t5, The time from time t6 to time t7, Each of these represents a pump non-operating time. A pump non-operating time is the time when there is no supply of liquid nitrogen and liquid nitrogen is consumed in the cell storage container 100 for cooling the cells. In the example shown in Figure 7, the time from time t6 to time t7 is shorter than the time from time t2 to time t3 and time t4 to time t5. The time from time t6 to time t7 can be understood as the time when not only is liquid nitrogen consumed for cooling, but there is also a possibility that liquid nitrogen may leak to the outside or that the insulation of the cell storage container 100 becomes insufficient. The process in step S629 in Figure 6 is a process for calculating this pump non-operating time (see Figure 9).

[0134] The processor of the control unit 400 terminates this process if it determines (NO) after executing the process in step S629 in Figure 6, or after the determination process in step S617 that the liquid level is not above the upper limit.

[0135] <<<Remaining quantity notification process>>> Figure 8 is a flowchart showing the process for determining and notifying the remaining amount of liquid nitrogen in the liquid nitrogen tank 500. This process is called and executed by the control unit 400 at predetermined intervals (for example, by interrupt processing). By performing this process, the volume of liquid nitrogen in the liquid nitrogen tank 500 can be constantly monitored.

[0136] First, the processor of the control unit 400 determines whether the cumulative supply amount has reached a predetermined amount or not (step S811). The cumulative supply amount is stored in the process of step S627 of the liquid nitrogen capacity maintenance process shown in Figure 6. In step S811, the cumulative supply amount is read from RAM and it is determined whether it has reached a predetermined amount or not. The predetermined amount is changed by the liquid nitrogen tank 500. It can be determined by the specifications of the liquid nitrogen tank 500 and stored in RAM or similar. For example, the predetermined amount can be 90% or 95% of the total capacity of the liquid nitrogen tank 500.

[0137] When the processor of the control unit 400 determines that the cumulative supply amount is equal to or greater than a predetermined amount (YES), it notifies the user via the display or speaker about the remaining amount of liquid nitrogen in the liquid nitrogen tank 500 (step S813). For example, it notifies the user of specific amounts such as the cumulative supply amount and the remaining amount of liquid nitrogen, as well as information such as whether the liquid nitrogen tank 500 is nearing the time for replacement and when the replacement time will be.

[0138] If the processor of the control unit 400 determines (NO) after executing the process in step S813, or in the determination process in step S811, that the cumulative supply amount is less than a predetermined amount, then this process is terminated.

[0139] <<<Abnormal Consumption Notification Processing>>> Figure 9 is a flowchart showing the process for notifying the amount of liquid nitrogen consumed in the cell storage container 100. This process is called and executed by the control unit 400 at predetermined intervals (for example, by interrupt processing). By performing this process, the state inside the cell storage container 100 can be constantly monitored.

[0140] First, the processor of the control unit 400 determines whether the pump non-operating time is below a predetermined value (step S911). The pump non-operating time is the time it takes for liquid nitrogen to be supplied from the liquid nitrogen tank 500. If liquid nitrogen leaks out of the cell storage container 100 or if the insulation of the cell storage container 100 is insufficient, the pump non-operating time will be shorter than usual.

[0141] When the processor of the control unit 400 determines that the pump non-operating time is below a predetermined value (NO), it notifies via the display and speaker that there may be an abnormality in the amount of liquid nitrogen consumed in the cell storage container 100 (step S913). The predetermined value can be the average value of normal pump non-operating times, the previous pump non-operating time, or any other value suitable for the determination.

[0142] The processor of the control unit 400 terminates this process after executing the process in step S913, or when it determines in the determination process in step S911 that the pump non-operating time is longer than a predetermined value (NO).

[0143] <<<Liquid phase to gas phase switching process>>> Figure 10 is a flowchart showing the process for switching the cell storage state from the liquid phase to the gas phase. This process is called and executed by the control unit 400 at predetermined intervals (for example, by interrupt processing). By performing this process, the volume of liquid nitrogen can be constantly monitored.

[0144] First, the processor of the control unit 400 switches the solenoid valves 600a, 600b, and 600c to the discharge state (second state) (step S1011). Specifically, it opens solenoid valves 600b and 600c and closes solenoid valve 600a.

[0145] Next, the processor of the control unit 400 determines whether the liquid level value indicated by the detection signal emitted from the liquid level sensor 200 is equal to or greater than the gas phase upper limit VU (step S1013).

[0146] When the processor of the control unit 400 determines that the liquid level is above the upper limit VU of the gas phase (YES), it outputs an operation control signal to the fluid pump 300 indicating the start of pump operation (step S1015). As a result, the fluid pump 300 starts operating in a discharge operation, and liquid nitrogen is discharged from the cell storage container 100 to the used tank 700.

[0147] Next, the processor of the control unit 400 determines whether the liquid level value indicated by the detection signal emitted from the liquid level sensor 200 is less than or equal to the gas phase upper limit VU (step S1017).

[0148] When the processor of the control unit 400 determines that the liquid level is below the upper limit VU of the gas phase (YES), it outputs an operation control signal to the fluid pump 300 indicating that the pump should be stopped (step S1019). As a result, the fluid pump 300 stops operating, and the discharge of liquid nitrogen into the used tank 700 is stopped.

[0149] If the processor of the control unit 400 determines that the liquid level is greater than the gas phase upper limit VU (NO), it returns to step S1017.

[0150] The processor of the control unit 400 terminates this process if it has executed the process in step S1019 or if it determines that the liquid level is below the upper limit VU of the gas phase (NO).

[0151] <<<Gas phase to liquid phase switching process>>> Figure 11 is a flowchart showing the process for switching the cell preservation state from the gas phase to the liquid phase. This process is called and executed by the control unit 400 at predetermined intervals (for example, by interrupt processing). By performing this process, the volume of liquid nitrogen can be constantly monitored.

[0152] First, the processor of the control unit 400 switches the solenoid valves 600a, 600b, and 600c to the supply state (first state) (step S1111). Specifically, it opens solenoid valves 600a and 600c and closes solenoid valve 600b.

[0153] Next, the processor of the control unit 400 determines whether the liquid level value indicated by the detection signal emitted from the liquid level sensor 200 is below the lower limit LL of the liquid phase (step S1113).

[0154] When the processor of the control unit 400 determines that the liquid level is below the lower limit LL of the liquid phase (YES), it outputs an operation control signal to the fluid pump 300 indicating the start of pump operation (step S1115). As a result, the fluid pump 300 starts operating in supply mode, and liquid nitrogen is supplied from the liquid nitrogen tank 500 to the cell storage container 100.

[0155] Next, the processor of the control unit 400 determines whether the liquid level value indicated by the detection signal emitted from the liquid level sensor 200 is equal to or greater than the lower limit LL of the liquid phase (step S1117).

[0156] When the processor of the control unit 400 determines that the liquid level is above the lower limit LL of the liquid phase (YES), it outputs an operation control signal to the fluid pump 300 indicating that the pump should be stopped (step S1119). As a result, the fluid pump 300 stops operating, and the supply of liquid nitrogen to the cell storage container 100 is stopped.

[0157] If the processor of the control unit 400 determines that the liquid level is below the lower limit LL of the liquid phase (NO), it returns to step S1017.

[0158] The processor of the control unit 400 terminates this process after executing the process in step S1019, or when it determines that the liquid level is greater than the lower limit LL of the liquid phase (NO).

[0159] <<<Modification 1>>> Figures 1 to 3 show a configuration in which the liquid nitrogen opening 120 is located near the bottom surface 112. However, the presence or absence and position of the liquid nitrogen opening 120 can be determined as appropriate, as long as liquid nitrogen can be guided into the cell storage container 100. If the liquid nitrogen opening 120 is not provided, liquid nitrogen can be guided into the cell storage container 100 from the opening 152. Even when the liquid nitrogen opening 120 is provided, its position can be determined as appropriate, depending on factors such as ease of operation and relative position to other equipment.

[0160] <<<Modification 2>>> In the example described above, the fluid pump 300 was shown as a configuration in which an electric field is generated from electrodes to cause fluid to flow. However, the fluid pump 300 is not limited to this. The fluid pump 300 may also have a configuration that includes movable parts. For example, the fluid pump 300 may be configured to cause fluid to flow by rotating an impeller.

[0161] <<<Modification 3>>> The liquid nitrogen tank 500 can be either a fixed tank or a portable tank. A fixed tank allows for a stable supply of liquid nitrogen even in environments with significant vibration and shock. On the other hand, a portable tank offers greater flexibility in the placement and arrangement of the equipment constituting the liquefied gas storage system. Furthermore, it allows for more efficient use of the space occupied by these devices, making miniaturization easier.

[0162] <<<Modification 4>>> The example described above shows a configuration with a movable platform 800. Using the movable platform 800 makes it easier to move and use. However, it is not limited to this, and a configuration without the movable platform 800 is also possible. This makes it less susceptible to the effects of vibration and shock, and also makes it easier to miniaturize the overall structure.

[0163] <<<<Scope of the Embodiment>>>> As described above, this embodiment has been presented. However, the descriptions and drawings that constitute part of this disclosure should not be understood as limiting. Various embodiments not described herein are included. [Industrial applicability]

[0164] Maintaining the environment within the cell storage container allows for the stable preservation of the cells contained within. [Explanation of symbols]

[0165] 100 cell storage container 180 Cell holding components (canes, boxes, etc.) 200 Liquid level sensor 250 Weight Sensor 300 Fluid Pump 400 Control Unit 500 liquid nitrogen tank 550a, 550b, 550c tube 600a, 600b, 600c Solenoid Valves 700 Used Tanks 800 Movable platform

Claims

1. A liquefied gas storage system equipped with cell storage containers for preserving contained cells at low temperatures while maintaining the volume of liquefied gas supplied from a liquefied gas tank.

2. A volume detection unit for detecting the volume of liquefied gas supplied to the cell storage container, The liquefied gas storage system according to claim 1, further comprising a volume adjustment unit for adjusting the volume of liquefied gas when the detected volume of liquefied gas exceeds a predetermined range.

3. The aforementioned height adjustment section is A supply operation in which liquefied gas is supplied from a liquefied gas tank to the cell storage container, A discharge operation to discharge liquefied gas from the cell storage container, The liquefied gas storage system according to claim 2, which can selectively perform the following.

4. The liquefied gas storage system according to claim 2, further comprising a control unit that determines whether or not the volume of the detected liquefied gas falls within the predetermined range.

5. A valve is further provided between the liquefied gas tank and the cell storage container. The liquefied gas storage system according to claim 4, wherein the control unit outputs an open command or a close command to the on / off valve.

6. It also features a movable mounting platform, The liquefied gas storage system according to claim 2, wherein at least the cell storage container and the volume detection unit are placed on the stand described above.

7. The liquefied gas storage system according to claim 2, wherein the volume adjustment unit operates in at least one of periodic or non-periodic operation.

8. The height adjustment unit, which operates in a non-periodic motion, has a non-movable member. The liquefied gas storage system according to claim 7, wherein the non-movable member displaces the liquefied gas.

9. The control unit, The volume adjustment unit stores the amount of liquefied gas supplied from the liquefied gas tank to the cell storage container. From the supply amount, at least one of the remaining amount in the liquefied gas tank and the replacement time for the liquefied gas tank is calculated. The liquefied gas storage system according to claim 2, which outputs warning information regarding the liquefied gas tank based on the remaining amount or replacement time.

10. The control unit, The liquefied gas storage system according to claim 2, wherein information regarding the consumption of liquefied gas in the cell storage container is output from the difference between a first timing at which the volume adjustment unit stops supplying liquefied gas to the cell storage container and a second timing at which the volume adjustment unit first starts supplying liquefied gas to the cell storage container after the first timing.

Images