Storage tank device configured to prevent ice formation

Abstract

To provide a cryogenic storage tank configured to detect a pressure of the tank and configured to remove ice formation without warming the entire cryogenic tank.SOLUTION: A cryogenic storage device 10 includes a storage tank 12 having an inner tank, an intermediate tank and an outer tank 16, which are spaced apart from each other so as to define a fluid reservoir for holding a cryogenic liquid and a thermal insulative space bounding the fluid reservoir. A top cover closes an open top. An inlet supplies the cryogenic liquid to the fluid reservoir. A fluid sensor is configured to detect a pressure within the cryogenic storage device and is removably disposed within the fluid reservoir so as to allow ice formation to be thawed without having to thaw the entire cryogenic storage device.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to cryogenic storage tanks. [Background technology]

[0002] Cryogenic storage tanks are used to store items at subarctic temperatures. For example, the cryogenic storage tank may be configured to store items at a temperature of -196° F. The cryogenic storage tank may include a fluid sensor configured to detect pressure within the tank to ensure sufficient cryogenic fluid is present.

[0003] 1 illustrates a current embodiment of a cryogenic storage device 100 in which a fluid sensor 102 is disposed within the evacuated interior space of a storage tank 104. The fluid sensor 102 is a tube fixedly coupled to a sensor unit 106 configured to detect pressure within the evacuated interior space; such sensor units are currently known and used and are illustratively shown as evacuated tubes. Temperature drops relative to the height of the cryogenic storage tank, which can cause ice to form within the tube of the fluid sensor 102, causing the sensor to detect inaccurate pressure.

[0004] To remove the ice, a service technician must heat the storage tank 104 above its melting point, as direct heat will not remove the ice because it will freeze instantly. Therefore, the items in the storage tank must be removed to a separate cold storage device during the thawing process.

[0005] Thus, it remains desirable to have a cryogenic storage tank configured to sense the pressure in the tank and to remove ice formation without warming the entire cryogenic tank. Summary of the Invention

[0006] The details of one or more implementations of the disclosure are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will become apparent from the description and drawings, and from the claims.

[0007] A cryogenic storage device for storing items in a cryogenic environment is provided. The cryogenic storage device includes a storage tank. The storage tank includes an inner tank and an outer tank. The inner tank is configured to hold a cryogenic liquid. The inner tank is spaced apart from the outer tank to form a thermally insulating space.

[0008] The fluid inlet is attached to the storage tank to supply a cryogenic liquid to a fluid reservoir of the inner tank, the cryogenic liquid being thermally isolated by the thermally insulating space. The fluid sensor is configured to detect pressure within the cryogenic storage device. The fluid sensor is removably positioned within the inner tank to allow thawing of ice formations without thawing the entire cryogenic storage device.

[0009] In one aspect, the fluid sensor is a capacitance sensor. In another aspect, the collar assembly includes an upper collar attached to the outer tank and a lower collar attached to the inner tank. The collar assembly is sealed to the inner and outer tanks to maintain the integrity of the thermally insulating space, and the fluid sensor is removably coupled to the upper collar.

[0010] In one aspect of the collar assembly, the upper and lower collars each have a slot extending along a radius of the respective upper and lower collar, and the intermediate tube is positioned within the slot of the respective upper and lower collar.

[0011] In one embodiment, the fluid sensor includes a head, the head being fixedly attached to the fluid sensor and removably attached to the collar assembly. For example, the head may be configured with a bore sized to receive the upper collar.

[0012] In one aspect of the cryogenic storage device, the head includes a vacuum port, the vacuum port being open to the thermally insulating space. In such an aspect, the cryogenic storage device may further include an air compressor.

[0013] In one aspect, the cryogenic storage device further includes a control housing that houses a control unit configured to process the liquid level detected by the liquid sensor in the inner tank to determine the amount of cryogenic liquid in the inner tank.

[0014] Other aspects of the cryogenic storage device are also contemplated herein, illustratively including a carousel rotatably mounted within the inner tank, a valve assembly for controlling the supply of cryogenic liquid into the inner tank, and / or a manual inlet fluidly coupled with the inner tank via a fluid inlet.

[0015] In this way, a cold storage device is provided that helps keep the cold storage device in operation by allowing ice formation that occurs at the fluid sensor to thaw upon removal of the fluid sensor, rather than thawing the entire cold storage device as is currently the case. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a description of a prior art cryogenic storage tank. [Figure 2] FIG. 1 is a perspective view of a cryogenic storage tank according to one or more embodiments described herein. [Figure 3] 3 is a cross-sectional view of FIG. 2 taken along line 3-3. [Figure 4] FIG. 2 is a perspective view showing the storage space of the low-temperature storage tank. [Figure 5A] FIG. 4 is an exploded view of the top of the cryogenic storage tank shown in FIG. 3. [Figure 5B] FIG. 4 is an exploded view of the bottom of the cryogenic storage tank shown in FIG. 3. [Figure 6] FIG. 3 is a rear view of FIG. 2.

[0017] Like reference symbols in the various drawings indicate like elements. DETAILED DESCRIPTION OF THE INVENTION

[0018] A cryogenic storage device is provided that eliminates the need to thaw the entire device to remove ice formation within a fluid sensor. The cryogenic storage device includes a storage tank having an inner tank and an outer tank spaced apart from each other to define a thermally insulating space surrounding the inner tank. A fluid inlet supplies cryogenic liquid to the inner tank. A fluid sensor is configured to detect a liquid level within the inner tank. The sensor is removably disposed within the storage tank and allows thawing of ice formation without thawing the entire cryogenic storage device.

[0019] Referring first to FIG. 2 , a cryogenic storage device 10 is provided in accordance with one or more embodiments described herein. The cryogenic storage device 10 is configured to store items, such as biological specimens, in a cryogenic environment. The cryogenic storage device 10 includes a storage tank 12. The storage tank 12 is a generally cylindrical body closed at the top and bottom. The cryogenic storage device 10 may include wheels and a handle. The handle is illustratively secured to the exterior of the storage tank 12 to facilitate movement of the cryogenic storage device 10.

[0020] For illustrative purposes, a storage tank 12 configured to hold 230 liters is preferably constructed of rigid and durable materials configured to withstand internal pressures in excess of 200 psi, such materials being currently known and used and illustratively including stainless steel. The dimensions and pressure capabilities of the storage tank 12 may deviate from the examples shown in the figures and described herein without departing from the scope of the appended claims.

[0021] Referring again to FIG. 2 and also to FIG. 3, the storage tank 12 includes an inner tank 14 and an outer tank 16. Preferably, the inner tank 14 and the outer tank 16 are made of a durable material suitable for use in cryogenic environments, such as stainless steel. The inner tank 14 is configured to hold items such as cryogenic liquids and biological samples. The inner tank 14 is spaced apart from the outer tank 16 to form a thermally insulating space 18. The thermally insulating space 18 extends along the periphery of the inner tank 14 and surrounds it. Preferably, the thermally insulating space 18 is evacuated.

[0022] Referring again to Figure 3 and also to Figure 4, the cold storage device 10 may further include a control housing 20. Each of the inner tank 14 and outer tank 16 is generally rounded, and the control housing 20 is mounted to the top surface of the outer tank 16. Preferably, the control housing 20 is welded to the top surface of the storage tank 12.

[0023] 4 is an exploded view showing the top of the storage tank 12 and the control housing 20 above the storage tank 12. A neck 22 is formed on the top of the storage tank 12. The neck 22 includes an opening 22a through the outer tank 16 and the inner tank 14 to provide access to the inner tank 14. The neck 22 may be formed of a thermally insulating composite material, such as fiberglass. The neck 22 may include a lid 24 for opening and closing the access. The lid 24 may be placed within the opening in the control housing 20 and locked to the neck 22.

[0024] A fluid inlet 26 is attached to the storage tank 12 to supply cryogenic liquid into the inner tank 14. In particular, the fluid inlet 26 extends through the outer tank 16 and the inner tank 14. A supply pipe 28 is fluidly coupled to the fluid inlet 26 to supply the cryogenic liquid. The supply pipe 28 extends toward the bottom of the inner tank 14. Preferably, the supply pipe 28 is formed of a rigid and durable material configured to operate in a cryogenic environment, such as stainless steel.

[0025] The cryogenic storage device 10 may further include a carousel 30 (shown in FIG. 3 ) disposed within the inner tank 14. The carousel 30 may be rotatably disposed within the inner tank 14. The carousel 30 is preferably formed of stainless steel and includes a plurality of spaced-apart trays, each of which may rotate independently of the others. The carousel 30 holds items within the inner tank 14 above a cryogenic liquid deposited at the bottom of the inner tank 14 to prevent damage to the items. In one embodiment of the carousel 30, the trays are stacked on top of each other and configured to rotate independently of each other, and may include openings to allow a user to access different trays.

[0026] 3 and now to FIG. 4, the cold storage device further includes a fluid sensor 32. The fluid sensor 32 is configured to detect pressure within the cold storage device 10. The fluid sensor 32 is removably disposed within the inner tank 14, thereby allowing ice formations to thaw without thawing the entire cold storage device 10.

[0027] 5A, one embodiment of a cold storage device 10 is provided, the cold storage device 10 including a collar 34 attached to the outer tank 16 and the inner tank 14. The collar 34 includes a bore 36 in which the fluid sensor 32 is located. The collar 34 is attached to the outer tank 16 and the inner tank 14 to maintain a vacuum within the thermally insulating space.

[0028] Referring again to FIG. 5A and also to FIG. 5B, one embodiment of the fluid sensor 32 and collar 34 will be described. In one embodiment, the fluid sensor 32 is a capacitance sensor 32a. The capacitance sensor 32a includes an inner rod 32b disposed within an outer sleeve 32c. The outer sleeve 32c has an open bottom to allow cryogenic liquid to rise therethrough. The inner rod 32b is centered within the outer sleeve 32c and spaced apart from the inner surface of the outer sleeve 32c. The inner rod 32b is fixed to the inner surface of the outer sleeve 32c to define a uniform gap between the outer surface of the inner rod 32b and the inner surface of the outer sleeve 32c. The fluid sensor 32 is configured to detect changes in electrical resistance to calculate the fluid level in the inner tank 14.

[0029] In another embodiment, the collar 34 includes an upper collar 34a attached to the outer tank 16 and a lower collar 34b attached to the inner tank 14. The collar 34 is sealed to the inner tank 14 and the outer tank 16 to maintain the integrity of the thermally insulating space 18, and the fluid sensor 32 is removably coupled to the upper collar 34a.

[0030] In one embodiment of the collars 34, the upper collar 34a and the lower collar 34b each have a slot 38 extending along a radius of the respective collar 34a and lower collar 34b. An intermediate tube 40 is disposed within the slot 38 of the respective collar 34a and lower collar 34b. In one embodiment, the intermediate tube 40 is made of glass-reinforced epoxy, such as G10 tubing, and is configured to retain its shape under vacuum pressure. It should be understood that the width of the intermediate tube 40 is wider than the width of the slot 38, forming a pinch-fit engagement between the intermediate tube 40 and the upper collar 34a and lower collar 34b to retain the vacuum pressure in the thermally insulating space 18.

[0031] In one embodiment, the fluid sensor 32 includes a head 42. The head 42 is fixedly attached to the fluid sensor 32 and removably attached to the collar 34. For example, the head 42 may be configured with a bore 42a sized to receive the upper collar 34a. A mechanical fastener, such as a set screw, may be threaded into a threaded opening in the upper collar 34a to secure and release the head 42 from the upper collar 34a.

[0032] In one embodiment of the cryogenic storage device 10, the head 42 includes a vacuum port 44. The vacuum port 44 opens to the thermally insulating space 18; for example, the head 42 may include a bore formed therein, or a corresponding bore may be formed in the upper collar 34a. The bore in the upper collar 34a opens to the thermally insulating space 18. The vacuum port 44 is fluidly coupled to the head 42 and configured to draw air from the thermally insulating space 18. In such an embodiment, the cryogenic storage device 10 may further include an air compressor (not shown) configured to draw air through the vacuum port 44.

[0033] 2-4, the control housing 20 houses a control unit 46. The control unit 46 is configured to execute instructions to perform fluid level and pressure control functions. For example, the control unit 46 may include computer resources (e.g., data processing hardware, a field programmable gate array ("FPGA"), etc.) for executing instructions configured to determine a fluid level based on information detected by the fluid sensor 32 to determine the amount of cryogenic liquid in the inner tank 14 and / or to operate an air compressor to maintain a vacuum in the thermally insulating space 18.

[0034] The cryogenic storage system 10 may further include a valve assembly 48 for controlling the supply of cryogenic liquid into the inner tank 14. The valve assembly 48 may further include a vent 50 for releasing pressure within the storage tank 12.

[0035] The cryogenic storage device 10 may further include a manual inlet 52 fluidly coupled to the inner tank 14 via the fluid inlet 26. FIG. 6 provides an example of a cryogenic storage device 10 having an automatic inlet 54 and a manual inlet 52. The automatic inlet 54 is fluidly coupled to the valve assembly 48 and the manual inlet 52, which couples the storage tank 12 to a source of cryogenic liquid. The pressure within the storage tank 12 is manipulated by the valve assembly 48 to introduce the cryogenic liquid from the source. In this manner, the cryogenic liquid may be introduced automatically or manually via the automatic inlet 54 or the manual inlet 52.

[0036] During operation, cryogenic liquid is introduced into the inner tank 14. Thus, the storage tank 12 is cooled to subarctic temperatures. Because the fluid sensor 32 is located within the inner tank 14 and exposed to subarctic temperatures, ice may form within the inner tube, which may cause erroneous readings. In particular, ice formation may cause the fluid sensor 32 to indicate a high pressure when the pressure within the inner tank 14 is below a predetermined pressure. The control unit 46 then transmits the high pressure reading to the user, which may result in a service call.

[0037] The service provider may simply remove the fluid sensor 32 to allow the ice to melt. For example, the service provider may simply remove the panel 56 from the control housing 20 and remove the mechanical fastener (set screw) to access the head 42 of the fluid sensor 32. The plug 58 is located on the top surface of the control housing 20, closing the opening 60. The plug 58 is removed from the opening 60, and the fluid sensor 32 is simply removed from the opening 60. The fluid sensor 32 is then allowed to thaw to room temperature, where ice formation has been eliminated. The fluid sensor 32 is then inserted through the opening, the head 42 is secured to the collar 34 by the mechanical fastener, and the panel 56 and plug 58 are attached. It should be understood that the cold storage device 10 may be operating during service. It should also be understood that the collar 34 maintains the vacuum in the thermally insulating space 18 during this operation.

[0038] In this manner, a cold storage device 10 is provided that helps maintain the cold storage device 10 in an operational state by melting any ice formation that occurs at the fluid sensor 32 upon removal of the fluid sensor 32, rather than melting the entire cold storage device 10 as is currently the case.

[0039] A number of embodiments have been described. Nevertheless, it will be understood that various modifications can be made without departing from the spirit and scope of the disclosure. Accordingly, other embodiments are within the scope of the following claims.

Claims

1. 1. A cryogenic storage device for storing items in a cryogenic environment, comprising a storage tank, the storage tank including an inner tank and an outer tank, the inner tank configured to hold a cryogenic liquid, the inner tank being disposed within the outer tank and spaced apart from an inner surface of the outer tank to define a thermally insulating space; a liquid inlet configured to supply a cryogenic liquid to a liquid reservoir of the inner tank; and a liquid sensor configured to detect a liquid level within the inner tank, the liquid sensor removably positioned within the inner tank to allow ice formations to thaw without thawing the entire cold storage device.

2. 10. The cryogenic storage device of claim 1, wherein the fluid sensor is a capacitance sensor.

3. 10. The cryogenic storage device of claim 1, further comprising a collar assembly having an upper collar attached to the outer tank and a lower collar attached to the inner tank, the collar assembly being sealed to the inner and outer tanks to maintain the integrity of the thermally insulating space, and the fluid sensor being removably coupled to the upper collar.

4. 4. The cryogenic storage device of claim 3, wherein the lower collar and the upper collar each comprise a cylindrical body having a through hole extending the axial length of the cylindrical body.

5. 5. The cryogenic storage device of claim 4, wherein the upper and lower collars each have a slot extending along a respective radius of the upper and lower collars, and the collar assembly further includes an intermediate tube disposed within the respective slot of the upper and lower collars.

6. 4. The cryogenic storage device of claim 3, wherein the fluid sensor includes a head removably attached to the collar assembly.

7. 7. The cryogenic storage device of claim 6, wherein the head includes a vacuum port open to the thermally insulating space.

8. 10. The cryogenic storage device of claim 1, further comprising a control housing for housing a control unit, the control unit configured to process a pressure sensor within the inner tank to determine a volume of cryogenic liquid within the inner tank.

9. 10. The cryogenic storage device of claim 1, further comprising a carousel rotatably mounted within the inner tank.

10. 10. The cryogenic storage device of claim 1, further comprising a valve assembly, a control inlet, and a manual inlet, wherein the control inlet is fluidly coupled to the valve assembly, the valve assembly is fluidly coupled to the liquid inlet, and the manual inlet is fluidly coupled to the liquid inlet.

11. 1. A cryogenic storage device for storing items in a cryogenic environment, comprising an inner tank and an outer tank, the inner tank being disposed within the outer tank and spaced from an inner surface of the outer tank to define a thermally insulating space, a fluid inlet configured to supply a cryogenic liquid to the fluid reservoir; a capacitance sensor configured to detect pressure within the cold storage device, the capacitance sensor having a tubular member open to the thermal space, the capacitance sensor removably positioned within the thermally insulating space to allow ice formations to thaw without having to thaw the entire cold storage device.

12. 12. The cryogenic storage device of claim 11, further comprising a collar assembly having an upper collar attached to the outer tank and a lower collar attached to the inner tank, the collar assembly sealed to the inner and outer tanks to maintain the integrity of the thermal space, and the fluid sensor removably coupled to the upper collar.

13. 13. The cold storage device of claim 12, wherein the lower collar and the upper collar each comprise a cylindrical body having a through hole extending the axial length of the cylindrical body.

14. 14. The cryogenic storage device of claim 13, wherein the upper and lower collars each have a slot extending along a respective radius of the upper and lower collars, and the collar assembly further includes an intermediate tube disposed within the respective slot of the upper and lower collars.

15. 14. The cryogenic storage device of claim 13, wherein the fluid sensor includes a head removably attached to the collar assembly.

16. 14. The cryogenic storage device of claim 13, wherein the fluid sensor includes a head removably attached to the collar assembly.

17. 17. The cryogenic storage device of claim 16, wherein the head includes a vacuum port open to the thermal space.

Images