Portable cooling unit

Abstract

A portable cooling unit includes: a multi-stage cascaded cooling system adapted to operate during transport of the portable cooling unit and adapted to be cooled to and maintained at a temperature greater than 70 K below ambient temperature; a suspension system arranged to serve as an elastic support for the multi-stage cascaded cooling system and / or components of the multi-stage cascaded cooling system; a motion limiting system arranged to restrict the movement of the multi-stage cascaded cooling system and / or the movement of its components; an impact protection system arranged to dampen collisions between the multi-stage cascaded cooling system and other parts of the portable cooling unit and / or collisions between components of the multi-stage cascaded cooling system; a lubrication system that facilitates lubrication of the components of the multi-stage cascaded cooling system when the portable cooling unit is tilted at least 10° from a horizontal orientation; and a monitoring system adapted to generate an alarm signal in the event of a malfunction in the portable cooling unit.

Description

Technical Field

[0001] This invention relates to a portable cooling unit for transporting temperature-sensitive items while maintaining a desired cooling temperature. Background Technology

[0002] Portable cooling units are generally known. However, such cooling units, which operate by passive cooling with dry ice or liquid nitrogen, cannot be used for highly temperature-sensitive items due to their instability over long periods and the dissipation of the limited supply of cooling medium.

[0003] Furthermore, portable cooling units based on Stirling cooling systems are not suitable for highly temperature-sensitive items because their relatively low cooling capacity hinders the rapid restoration of the desired or required cooling temperature, for example, after a door has been opened.

[0004] Typically, these portable cooling units cannot cool to and maintain a temperature 60K to 70K below ambient temperature, making them unsuitable for transporting highly temperature-sensitive items such as vaccines.

[0005] On the other hand, stationary cooling units avoid some of the disadvantages mentioned above. However, because stationary systems are used only under controlled conditions, such as in indoor laboratories or storage areas, they are not suitable for large differences between ambient temperature and the desired cooling temperature; instead, these systems are designed to operate within a specific predetermined ambient temperature or a narrow ambient temperature range. This also applies to other environmental conditions, such as ambient pressure.

[0006] Furthermore, fixed systems are not permitted to operate when tilted; in other words, fixed systems are not portable. On the contrary, such tilting can cause the fixed system to malfunction or be damaged.

[0007] Therefore, there is a lack of transportable cooling units that are used to reliably transport highly temperature-sensitive items while maintaining them at a desired cooling temperature greater than 70K below ambient temperature under varying environmental conditions. Summary of the Invention

[0008] Therefore, the object of the present invention is to provide a portable cooling unit for reliably transporting highly temperature-sensitive items while maintaining a desired cooling temperature greater than 70K below the ambient temperature over extended periods of time under varying environmental conditions.

[0009] Another object of the present invention will become apparent from the following description of the invention.

[0010] Description of the present invention

[0011] The objective of this invention is achieved by means of a portable cooling unit for transporting temperature-sensitive items while maintaining a desired cooling temperature, the portable cooling unit comprising:

[0012] - A multi-stage cascaded refrigeration system suitable for operation during transport of a portable cooling unit, and suitable for cooling to and maintaining at a temperature greater than 70K, preferably greater than 120K, below ambient temperature.

[0013] - A suspension system adapted and arranged to serve as a resilient support for components of a multi-stage cascaded refrigeration system and / or a multi-stage cascaded refrigeration system.

[0014] - A motion clearance system adapted and arranged to restrict the motion of a multi-stage cascaded refrigeration system and / or the motion of its components.

[0015] - Impact protection system, adapted and arranged to dampen collisions between the multi-stage cascaded refrigeration system and other parts of the portable cooling unit and / or collisions between components of the multi-stage cascaded refrigeration system.

[0016] - A lubrication system that facilitates the lubrication of components in a multi-stage cascaded refrigeration system when the portable cooling unit is tilted at least 10°C, preferably more than 20°C, from a horizontal orientation.

[0017] - A monitoring system adapted to generate alarm signals when a portable cooling unit malfunctions.

[0018] Due to this specific combination of features, the portable cooling unit avoids all the aforementioned drawbacks. The employed multi-stage cascaded refrigeration system provides sufficient cooling power and achieves and maintains the desired or required cooling temperature, i.e., the target temperature; the suspension system, motion clearance system, and impact protection system serve as dedicated protection devices for the multi-stage cascaded refrigeration system during transport, thereby adapting the multi-stage cascaded refrigeration system for operation during transport and thus making the cooling unit portable; the lubrication system reliably prevents the multi-stage cascaded refrigeration system from failing when in a tilted position, which the portable cooling unit typically assumes during transport; and the monitoring system ensures protection for temperature-sensitive items in the event of a cooling unit failure, as this monitoring system allows for early detection of the fault and rapid intervention.

[0019] The term "portable" within the scope of this invention means that the cooling unit is able to operate normally during transport, particularly when the cooling unit is tilted at least 10° from a horizontal orientation.

[0020] In a preferred embodiment of the portable cooling unit according to the invention, the portable cooling unit weighs 50 kg or less.

[0021] This makes it easier for the person in charge to operate the portable cooling unit, as the increased weight would increase the risk of injury or damage and make the operation more difficult.

[0022] In a preferred embodiment of the portable cooling unit according to the invention, the portable unit includes at least one, preferably two, handles to facilitate operation of the portable unit.

[0023] This further improves the handling safety and stability of the cooling unit during transport. In particular, it makes it easier to keep the cooling unit in a horizontal orientation, thereby minimizing the risk of failure of the multi-stage cascaded refrigeration system and its components during transport.

[0024] In another preferred embodiment of the portable cooling unit according to the invention, the multi-stage cascaded refrigeration system is implemented as a two-stage cascaded refrigeration system.

[0025] The use of a two-stage cascaded refrigeration system makes portable cooling units suitable for operation in a particularly efficient manner over a wide range of ambient temperatures. When the two-stage cascaded refrigeration system has a simple and robust design sufficient for portable cooling units, it allows the desired temperature difference to be divided into two steps by utilizing two thermally connected standard refrigeration systems, such as two vapor compression refrigeration systems. In the first step, the ambient temperature of the ambient air in the cooling unit is cooled to an intermediate temperature, also known as the intercooler temperature, and in the second step, it is cooled from said intermediate temperature to the target temperature of the cooling unit, also known as the target temperature. Therefore, one can rely entirely on standard components found in other devices used in the light commercial cooling industry without losing reliability due to overload when dealing with the temperature differences associated with standalone portable cooling units.

[0026] In another preferred embodiment of the portable cooling unit according to the invention, the high-temperature refrigeration cycle of the two-stage cascaded refrigeration system includes a first compressor, the condenser of which has a cooling capacity of 60W at an ambient temperature of 43°C, and the evaporator of which has an intercooler temperature of -25°C.

[0027] In another preferred embodiment of the portable cooling unit according to the invention, the cryogenic refrigeration cycle of the two-stage cascaded refrigeration system includes a second compressor, the condenser of which has a cooling capacity of 30W at an intercooler temperature of -25°C, and the evaporator of which has a target temperature of -80°C.

[0028] This design of the two-stage cascaded refrigeration system enables the portable cooling unit to cool highly temperature-sensitive items to and maintain that temperature without overloading the refrigeration cycle (e.g., a vapor compression refrigeration system).

[0029] The evaporator of the high-temperature refrigeration cycle and the condenser of the low-temperature refrigeration cycle, together with the thermal connection between the evaporator and the condenser, form the intercooler of a two-stage cascaded refrigeration system. The high-temperature refrigeration cycle can be designed to dissipate 120W of heat between the condenser and ambient air at a temperature difference of 10K, and to absorb 60W of heat at the evaporator (i.e., the intercooler) at a temperature difference of 5K. On the other hand, the second refrigeration cycle can be designed to dissipate 60W of heat at the condenser (i.e., the intercooler) at a temperature difference of 5K, and to absorb 30W of heat from the activated cooling compartment to the evaporator at a temperature difference of 10K. Therefore, the cooling compartment is defined as the volume portion of the portable cooling unit for storing temperature-sensitive items.

[0030] This design allows the portable cooling unit to quickly re-establish the target temperature after the cooling process is interrupted, such as when the door to the cooling compartment is opened.

[0031] In another preferred embodiment of the portable cooling unit according to the invention, the high-temperature refrigeration cycle of the two-stage cascaded refrigeration system uses propane as a refrigerant, and the low-temperature refrigeration cycle of the two-stage cascaded refrigeration system uses ethane as a refrigerant.

[0032] By combining these specific refrigerants for high-temperature and low-temperature refrigeration cycles, two-stage cascade systems can operate in a particularly efficient manner, especially under the different external conditions encountered by the two-stage cascade systems during transport.

[0033] In another preferred embodiment of the portable cooling unit according to the invention, the compressor of each refrigeration cycle has a motor compression unit that is elastically suspended inside the housing of the respective compressor by means of a plurality of elastic elements.

[0034] Therefore, vibration and sound transmission between the motor compressor unit and the compressor housing can be minimized. Furthermore, by elastically suspending the motor compressor unit inside the corresponding compressor housing, the compressor becomes particularly suitable for portable use because different orientations and / or positions of the compressor do not affect the operability of the motor compressor unit. Moreover, since the elastic suspension can be achieved by multiple elastic elements supported at the base of the compressor housing, these elastic elements are at least partially immersed in the lubricant groove (or oil groove) covering the base during compressor operation, which further dampens vibration and sound transmission.

[0035] In another preferred embodiment of the portable cooling unit according to the invention, the motor compression unit has a plurality of spacer elements made of an elastic material, the spacer elements being arranged on the surface of the motor compression unit and protruding from the surface toward the housing of the compressor.

[0036] The resilient spacer element serves as a dedicated protective device to prevent collisions between the motor compressor unit and the corresponding compressor housing. This protection is essential for the portability of the cooling unit, ensuring its proper operation regardless of its orientation or position during transport. Therefore, the spacer element can function as an impact protection system. The resilient spacer element can also serve as a motion limiting system because its dimensions can be selected to allow only predetermined displacement from the stationary position of the motor compressor unit.

[0037] In another preferred embodiment of the portable cooling unit according to the invention, the compressor has a lubricant receiving portion attached to the crankshaft of the motor compression unit such that the lubricant receiving portion at least partially protrudes into the lubricant reservoir of the compressor.

[0038] In this way, stable lubrication of the motor compression unit can be ensured, even when the cooling unit is not horizontally oriented. In this case, the lubricant receiving portion still protrudes at least partially into the lubricant reservoir covering the base of the compressor housing during compressor operation, thereby facilitating a stable supply of lubricant to critical components requiring lubrication. Lubricant can be delivered from the reservoir to the critical components using standard devices for lubricant delivery, such as grooves in the surface of the crankshaft, eccentric bores within the crankshaft, and / or outlet openings.

[0039] In a preferred embodiment, lubricant enters the lubricant receiver and crankshaft through the inlet opening of the lubricant receiver and can form a lubricant parabola as the crankshaft rotates—which also causes the lubricant receiver attached to the crankshaft to rotate. The lubricant can then exit from the interior of a rotationally symmetrical hollow region of the crankshaft through an outlet opening located on the outer surface of the crankshaft at the highest point of the lubricant parabola. From there, the lubricant can be directed toward critical components requiring lubrication in the motor compression unit, or it can be directed to another delivery device, such as grooves in the surface of the crankshaft. Attached Figure Description

[0040] The invention will now be briefly described using the accompanying drawings of exemplary embodiments. Thus, it is shown that:

[0041] Figure 1 A 3D view of a portable cooling unit;

[0042] Figure 2 A schematic diagram of a compressor in one refrigeration cycle of a multi-stage cascaded refrigeration system;

[0043] Figure 3 A perspective view of a portable cooling unit in a tilted orientation during transport;

[0044] Figure 4 A schematic diagram of a compressor in a refrigeration cycle of a multi-stage cascaded refrigeration system that is tilted during transport. Detailed Implementation

[0045] Figure 1 A portable cooling unit 1 according to the present invention is shown, the cooling unit 1 having two handles 2 located on opposite outer surfaces of the body of the cooling unit 1 (together with...). Figure 2 compared to, Figure 1 (Only one of the two handles 2 can be seen). The cooling unit 1 is divided into an isolated cooling compartment 6 and a separate machine compartment 7, which stores highly temperature-sensitive items during transport. The machine compartment 7 houses a multi-stage cascaded refrigeration system. The cooling compartment 6 is isolated from ambient air by a door 8.

[0046] The multi-stage refrigeration system can be implemented as a two-stage cascaded refrigeration system, comprising two vapor compression refrigeration systems, which respectively form a high-temperature refrigeration cycle and a low-temperature refrigeration cycle. Each of these refrigeration cycles includes a compressor, which is designed as follows: Figure 2 As shown in the image.

[0047] exist Figure 2 In the diagram, the compressor is shown as comprising a compressor housing 9 and a motor compression unit 3, which is elastically suspended on the base 10 of the compressor housing 9 by means of a plurality of elastic elements 11 forming a suspension system. The motor compression unit 3 has a plurality of spacer elements 4 made of elastic material, which are arranged on the outer surface of the motor compression unit 3 and protrude from the outer surface toward the compressor housing 9. These spacer elements 4 serve as an impact protection system because the elastic design of these spacer elements 4 dampens any collision between the elastically suspended motor compression unit 3 and the compressor housing 9. Simultaneously, the spacer elements 4 can be used as a motion clearance system by selecting the dimensions of the spacer elements 4 such that only a predetermined displacement from the resting position of the motor compression unit 3 is allowed. Figure 4 ).

[0048] also, Figure 2 and Figure 4 A lubricant receiving portion 5 is schematically shown, attached to the crankshaft (not shown) of the motor compressor unit 3, such that the lubricant receiving portion 5 protrudes into the lubricant reservoir 12 of the compressor. This lubricant receiving portion 5 can form a lubrication system together with other means for lubricant delivery, such as grooves in the surface of the crankshaft, eccentric holes within the crankshaft, and / or outlet openings. This lubrication system ensures stable lubrication of the motor compressor unit 3 (or components of the motor compressor unit 3), even when the portable cooling unit 1 is tilted at an angle α from a horizontal orientation (e.g., ...). Figure 3 and Figure 4This is also true in the case shown in the diagram. When a compressor used in a stationary refrigeration system is at risk of serious damage due to lack of lubrication when tilted, this is because at least a portion of the bottom area of ​​the motor compressor unit 3 is no longer submerged in the lubricant reservoir 12, and the lubricant receiving part 5 still protrudes into the lubricant reservoir 12, even in this tilted ( Figure 4 The same applies in the case of ( ).

[0049] Because malfunctions of the portable cooling unit 1 must be detected and addressed immediately to prevent damage to or rendering of highly temperature-sensitive items (such as vaccines) unusable, the portable cooling unit 1 also includes a monitoring system adapted to generate an alarm signal immediately upon malfunction of the portable cooling unit. The alarm signal may be generated, for example, upon detection of a certain temperature rise in the cooling compartment, and / or exceeding a certain tilt angle α, and / or exceeding a certain ambient temperature.

[0050] List of reference numerals

[0051] 1 Portable cooling unit

[0052] 2 handles

[0053] 3-motor compression unit

[0054] 4. Spacer Components

[0055] 5. Lubricant receiving section

[0056] 6 Cooling compartments

[0057] 7 Machine compartments

[0058] 8. Doors to the cooling compartments

[0059] 9. Compressor housing

[0060] 10. Base of the compressor housing

[0061] 11. Elastic components

[0062] 12. Lubricant tank.

Claims

1. A portable cooling unit (1) for transporting temperature-sensitive items while maintaining a desired cooling temperature, the portable cooling unit (1) comprising: - A multi-stage cascaded refrigeration system, the multi-stage cascaded refrigeration system being adapted to operate during transport of the portable cooling unit (1), and the multi-stage cascaded refrigeration system being adapted to cool to and maintain a temperature greater than 70 K below ambient temperature. - A suspension system, which is arranged to serve as a resilient support for the multi-stage cascaded refrigeration system and / or components of the multi-stage cascaded refrigeration system. - A motion control system, arranged to restrict the motion of the multi-stage cascaded refrigeration system and / or the motion of the components of the multi-stage cascaded refrigeration system. - An impact protection system, which is arranged to dampen collisions between the multi-stage cascaded refrigeration system and other parts of the portable cooling unit (1) and / or collisions between the components of the multi-stage cascaded refrigeration system. - A lubrication system that facilitates the lubrication of the components of the multi-stage cascaded refrigeration system when the portable cooling unit (1) is tilted at least 10° from a horizontal orientation, and - A monitoring system adapted to generate an alarm signal when the portable cooling unit (1) malfunctions. -The multi-stage cascaded refrigeration system is implemented as a two-stage cascaded refrigeration system, which includes two vapor compression refrigeration systems.

2. The portable cooling unit (1) according to claim 1, characterized in that The lubrication system facilitates the lubrication of the components of the multi-stage cascaded refrigeration system when the portable cooling unit (1) is tilted more than 20° from the horizontal orientation.

3. The portable cooling unit (1) according to claim 1, characterized in that The portable cooling unit (1) weighs 50 kg or less.

4. The portable cooling unit (1) according to any one of claims 1 to 3, characterized in that The portable cooling unit (1) includes at least one handle (2) for improving the operation of the portable cooling unit (1).

5. The portable cooling unit (1) according to claim 1, characterized in that The high-temperature refrigeration cycle of the two-stage cascaded refrigeration system includes a first compressor, the condenser of the first compressor in the high-temperature refrigeration cycle having a cooling capacity of 60W at an ambient temperature of 43°C, and the evaporator of the first compressor in the high-temperature refrigeration cycle having an intercooler temperature of -25°C.

6. The portable cooling unit (1) according to claim 1, characterized in that The low-temperature refrigeration cycle of the two-stage cascaded refrigeration system includes a second compressor, the condenser of the low-temperature refrigeration cycle of the second compressor having a cooling capacity of 30W at an intercooler temperature of -25°C, and the evaporator of the low-temperature refrigeration cycle of the second compressor having a desired cooling temperature of -80°C.

7. The portable cooling unit (1) according to claim 5, characterized in that The low-temperature refrigeration cycle of the two-stage cascaded refrigeration system includes a second compressor, the condenser of the low-temperature refrigeration cycle of the second compressor having a cooling capacity of 30W at an intercooler temperature of -25°C, and the evaporator of the low-temperature refrigeration cycle of the second compressor having a desired cooling temperature of -80°C.

8. The portable cooling unit (1) according to claim 7, characterized in that The high-temperature refrigeration cycle of the two-stage cascaded refrigeration system uses propane as the refrigerant, and the low-temperature refrigeration cycle of the two-stage cascaded refrigeration system uses ethane as the refrigerant.

9. The portable cooling unit (1) according to claim 7, characterized in that The first compressor of the high-temperature refrigeration cycle and the second compressor of the low-temperature refrigeration cycle both have a motor compression unit (3), which is elastically suspended inside the housing of the corresponding first compressor or the housing of the second compressor by means of a plurality of elastic elements (11).

10. The portable cooling unit (1) according to claim 9, characterized in that The motor compression unit (3) has a plurality of spacer elements (4) made of elastic material, the spacer elements (4) being arranged on the surface of the motor compression unit (3) and protruding from the surface toward the housing of the corresponding first compressor or the housing of the second compressor.

11. The portable cooling unit (1) according to claim 9, characterized in that The first compressor and the second compressor have a lubricant receiving portion (5) attached to the crankshaft of the motor compression unit (3) such that the lubricant receiving portion (5) protrudes at least partially into the lubricant reservoir of the corresponding first compressor or the lubricant reservoir of the second compressor.

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