Medical preservation box and arrangement method of evaporation pipeline thereof

Abstract

The present disclosure relates to a medical preservation box and an arrangement method of an evaporation pipeline thereof, wherein the medical preservation box comprises a shell including a top, a bottom and a circumferential side, the circumferential side is composed of a door and a plurality of side surfaces, the plurality of side surfaces are divided into a top region, a middle region and a bottom region along a direction from the top to the bottom; and an evaporation pipeline is arranged in the plurality of side surfaces; a pipeline length of the evaporation pipeline in a first sub-region of the top region is greater than a pipeline length in a second sub-region of the middle region; a pipeline length of the evaporation pipeline in a third sub-region in the bottom region is less than or greater than the pipeline length in the second sub-region of the middle region; an area of the first sub-region is equal to an area of the second sub-region, and an area of the first sub-region is equal to an area of the third sub-region. The embodiments of the present disclosure can improve the uniformity of the temperature in the shell, so as to alleviate the problem of uneven temperature in the medical preservation box.

Description

Technical Field

[0001] This disclosure relates to the field of refrigeration technology, and in particular to a medical storage box and a method for arranging its evaporation pipes. Background Technology

[0002] Common cooling methods for cryogenic refrigeration equipment are divided into air cooling and direct cooling. Compared with air cooling, direct cooling has a higher utilization rate of the refrigeration space. In some related technologies, direct cooling is designed with evaporator pipes evenly arranged on the surface of the inner liner to cool the space inside. However, for large medical cryogenic storage chambers, because the evaporator pipes are nearly 100 meters long, the evaporation temperature of the refrigerant decreases along the evaporation pressure, and factors such as natural air convection within the chamber can cause uneven temperature distribution within the large medical cryogenic storage chamber. Summary of the Invention

[0003] Some embodiments of this disclosure propose a method for arranging a medical preservation box and its evaporation pipes to alleviate the problem of uneven temperature inside the medical preservation box.

[0004] In one aspect of this disclosure, a medical storage box is provided, comprising:

[0005] A housing, comprising a top, a bottom, and circumferential sides, the circumferential sides being formed by a door and a plurality of side surfaces, the plurality of side surfaces being divided into a top region, a middle region, and a bottom region along a direction from the top to the bottom; and

[0006] An evaporation pipe is provided on the plurality of sides; the pipe length of the evaporation pipe in the first sub-region of the top region is greater than the pipe length in the second sub-region of the middle region; the pipe length of the evaporation pipe in the third sub-region of the bottom region is less than or greater than the pipe length in the second sub-region of the middle region; the area of ​​the first sub-region is equal to the area of ​​the second sub-region, and the area of ​​the first sub-region is equal to the area of ​​the third sub-region.

[0007] In some embodiments, the ratio of the length of the evaporation pipe in the second sub-region to the length of the evaporation pipe in the first sub-region ranges from 0.5 to 0.9.

[0008] In some embodiments, the length of the evaporation pipe in the third sub-region is less than the length of the pipe in the second sub-region, and the ratio of the length of the evaporation pipe in the third sub-region to the length of the evaporation pipe in the second sub-region ranges from 0.75 to 0.85.

[0009] In some embodiments, the length of the evaporation pipe in the second sub-region is less than the length of the pipe in the third sub-region, and the ratio of the length of the evaporation pipe in the second sub-region to the length of the evaporation pipe in the third sub-region is in the range of 0.75 to 0.85.

[0010] In some embodiments, the length of the evaporation pipe in the first sub-region is greater than the length of the evaporation pipe in the third sub-region.

[0011] In some embodiments, the ratio of the length of the evaporation pipe in the third sub-region to the length of the evaporation pipe in the first sub-region ranges from 0.6 to 0.8.

[0012] In some embodiments, along the direction from the top to the bottom, the length of the evaporation pipe in the second sub-region closer to the top of the two second sub-regions of the central region is greater than the length of the evaporation pipe in the second sub-region closer to the bottom.

[0013] In some embodiments, the ratio of the length of the evaporation pipe in the second sub-region near the bottom to the length of the evaporation pipe in the second sub-region near the top of the central region ranges from 0.75 to 0.85.

[0014] In some embodiments, the evaporation pipes are arranged in a zigzag pattern on the plurality of sides, and the first average spacing between adjacent pipes of the evaporation pipes is less than the second average spacing, wherein the first average spacing is the average spacing between adjacent pipes of the evaporation pipes in the top region, and the second average spacing is the average spacing between adjacent pipes of the evaporation pipes in the middle region.

[0015] In some embodiments, the evaporation pipes are arranged in a zigzag pattern on the plurality of sides, and the third average spacing between adjacent pipes of the evaporation pipes is less than the second average spacing, wherein the third average spacing is the average spacing between adjacent pipes of the evaporation pipes in the bottom region, and the second average spacing is the average spacing between adjacent pipes of the evaporation pipes in the middle region.

[0016] In some embodiments, the evaporator conduit is configured to allow refrigerant within it to flow in a direction from the top to the bottom.

[0017] In some embodiments, the evaporation pipes are also evenly arranged at the top, and / or, the evaporation pipes are also evenly arranged at the bottom.

[0018] In some embodiments, the central region includes two second sub-regions, wherein the evaporation pipes within the two second sub-regions are of equal length.

[0019] In one aspect of this disclosure, a method for arranging the evaporation pipes of a medical storage box is provided, comprising the following steps: dividing multiple sides of the shell of the medical storage box into n regions along a direction from top to bottom according to a preset area ratio;

[0020] The heat flux of each region is obtained based on the wall temperature of the shell in each region, the geometric mean temperature of the refrigerant in the evaporator pipes in each region when evaporator pipes are arranged, and the contact area between the evaporator pipes and the wall in each region.

[0021] Based on the fact that the heat flux ratio of each region is the same as the preset area ratio, the ratio of the contact area between the evaporation pipe and the shell wall of two adjacent regions is obtained.

[0022] Based on the ratio of the contact area between the evaporation pipes and the shell wall of two adjacent regions, the length of the evaporation pipes that should be arranged in each region is obtained.

[0023] Evaporation pipes of corresponding length are laid out in each area.

[0024] In some embodiments, arranging evaporation pipes of corresponding length in each region includes: uniformly arranging evaporation pipes of corresponding length in each region by folding them back and forth within that region.

[0025] In some embodiments, obtaining the heat flux of each region includes: based on Q i =hA i (t wi -t eqvi Obtain the heat flux for each region;

[0026] Among them, Q i Let be the heat flux of the i-th region;

[0027] h is the local heat transfer coefficient of the boiling flow inside the evaporation pipe;

[0028] A i Let be the contact area between the evaporation pipe and the wall of the shell in the i-th region;

[0029] t wi Let be the wall temperature of the shell in the i-th region;

[0030] t eqvi Let be the geometric mean temperature of the refrigerant in the evaporator pipe within the i-th region;

[0031] The value of i is [1, n].

[0032] In some embodiments, the proportional relationship between the contact area between the evaporation pipe and the shell wall of two adjacent regions is obtained based on the fact that the proportion of heat flux in each region is the same as the preset area proportion.

[0033] according to get:

[0034]

[0035] in,

[0036] Q i+1 Let be the heat flux of the (i+1)th region;

[0037] A i+1 Let be the contact area between the evaporation pipe and the wall of the shell in the (i+1)th region;

[0038] t w(i+1) Let be the wall temperature of the shell in the (i+1)th region;

[0039] t eqv(i+1) Let be the geometric mean temperature of the refrigerant in the evaporator pipe within the (i+1)th region;

[0040] Let a be the area of ​​the i-th region. i The area a of the (i+1)th region i+1 The ratio of .

[0041] In some embodiments, t wi and t w(i+1) All are set values, and t wi =t w(i+1) .

[0042] In some embodiments, the length of the evaporation pipe to be arranged in each region is obtained based on the ratio of the contact area between the evaporation pipe and the wall of the shell in two adjacent regions, including:

[0043] The ratio of the evaporation pipe lengths of two adjacent regions is obtained by the ratio of the contact area between the evaporation pipes and the shell wall of two adjacent regions. The evaporation pipe length of each region is obtained by the ratio of the evaporation pipe lengths of two adjacent regions and the total length of the evaporation pipes.

[0044] In some embodiments, the geometric mean temperature t of the refrigerant in the evaporator pipe of any region eqv for:

[0045] in,

[0046] t eq(x) represents the friction temperature distribution within the evaporation pipe, which is obtained based on the friction pressure distribution P(x) within the evaporation pipe.

[0047] x is the length of the evaporation pipe in this area; x = x2 - x1;

[0048] x1 is the starting length of the evaporation pipe in this area;

[0049] x2 represents the length of the evaporation pipe at the end of the pipe in this area.

[0050] In some embodiments, the friction pressure distribution P(x) in the evaporation pipe is obtained based on the inlet pressure of the evaporation pipe and the friction pressure drop ΔP in the evaporation pipe.

[0051] In some embodiments, the friction drop ΔP in the evaporation pipe is obtained based on the pressure drop of the liquid single-phase flow straight pipe and the pressure drop of the gas single-phase flow straight pipe in the evaporation pipe.

[0052] In some embodiments, the pressure drop along the evaporation pipe

[0053] Among them, the conversion factor

[0054] A1, A2, A3, and A4 are all constants;

[0055]

[0056] ΔP l For pressure drop in a straight pipe for single-phase liquid flow;

[0057] ΔP g This refers to the pressure drop in a straight pipe for single-phase gas flow.

[0058] In some embodiments, the pressure drop in a single-phase liquid flow straight pipe Among them, friction coefficient Reynolds number Liquid phase conversion rate

[0059] In the formula, V ol G represents the liquid phase reduced velocity. l ρ is the liquid phase flow rate; l U is the liquid phase density; l denoted as ρ, where A is the viscosity of the liquid phase; D is the inner cross-sectional area of ​​the evaporation pipe; and L is any length of the evaporation pipe.

[0060] In some embodiments, the pressure drop in a single-phase gas flow straight pipe Among them, friction coefficient Reynolds number Gas phase conversion rate

[0061] In the formula, V og G represents the gas phase reduced velocity. g ρ is the gas phase flow rate; g U is the gas phase density; g denoted as V0, where A is the viscosity of the gas phase; D is the inner cross-sectional area of ​​the evaporation pipe; and L is any length of the evaporation pipe.

[0062] Based on the above technical solution, this disclosure has at least the following beneficial effects:

[0063] In some embodiments, evaporation pipes are arranged on multiple sides of the shell of the medical storage box. The pipe length of the evaporation pipe in the first sub-region of the top region is greater than the pipe length in the second sub-region of the middle region. When the refrigerant is sufficient, the pipe length of the evaporation pipe in the third sub-region of the bottom region is less than the pipe length in the second sub-region of the middle region. When the refrigerant is insufficient, the pipe length of the evaporation pipe in the third sub-region of the bottom region is greater than the pipe length in the second sub-region of the middle region. Therefore, the uniformity of temperature inside the shell can be improved to alleviate the problem of uneven temperature inside the medical storage box. Attached Figure Description

[0064] The accompanying drawings, which are included to provide a further understanding of this disclosure and form part of this application, illustrate exemplary embodiments of this disclosure and are used to explain this disclosure, but do not constitute an undue limitation of this disclosure. In the drawings:

[0065] Figure 1 This is a diagram showing the heat flux density and temperature distribution when the evaporator pipes are uniformly distributed along the surface of the shell.

[0066] Figure 2 This is a schematic diagram of the housing of a medical storage box provided according to some embodiments of the present disclosure;

[0067] Figure 3 This is a schematic diagram showing the unfolded sides of the housing of a medical storage box provided according to some embodiments of the present disclosure, with evaporation pipes arranged on the sides.

[0068] The labels in the attached diagram are explained as follows:

[0069] 1-Shell; 11-Top; 12-Bottom; 13-Circumferential side; 131-Door; 132-Multiple sides; 132a-First side; 132b-Second side; 132c-Third side;

[0070] 2-Evaporation pipe; 21-Branch pipe; 22-Connection part;

[0071] D1 - First region; D2 - Second region; D3 - Third region; D4 - Fourth region;

[0072] S1 - First curve; S2 - Second curve; S3 - Third curve.

[0073] It should be understood that the dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale. Furthermore, the same or similar reference numerals denote the same or similar components. Detailed Implementation

[0074] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the present disclosure or its application or use. The present disclosure may be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that the present disclosure will be thorough and complete, and will fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless specifically stated otherwise, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0075] The terms "first," "second," and similar words used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "contains" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. Terms such as "above," "below," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, this relative positional relationship may also change accordingly.

[0076] In this disclosure, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may be not directly connected to the other devices but have an intermediary device.

[0077] All terms used in this disclosure (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as a dictionary, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0078] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0079] For large medical storage boxes, the evaporation pipes are nearly 100 meters long. Due to the influence of viscous resistance, the evaporation temperature of the refrigerant in the evaporation pipe decreases along the evaporation pressure, resulting in a certain temperature difference between the inlet and outlet of the evaporation pipe. In addition, the uneven temperature distribution in the storage box causes natural air convection, which leads to uneven temperature inside the medical storage box.

[0080] Based on this, the present disclosure provides a medical preservation box and a method for arranging its evaporation pipes, thereby improving the uniformity of temperature inside the box through the reasonable layout of the evaporation pipes.

[0081] Figure 2 and Figure 3 This is a structural schematic diagram of some embodiments of the medical storage box according to this disclosure. (Reference) Figure 2 and Figure 3 In some embodiments, the medical storage box includes a housing 1 and an evaporation pipe 2.

[0082] refer to Figure 2 The housing 1 includes a top 11, a bottom 12 and a circumferential side 13, which is composed of a door 131 and a plurality of side surfaces 132.

[0083] Multiple sides 132 are divided into a top region, a middle region and a bottom region along the direction from the top 11 to the bottom 12.

[0084] Evaporation pipe 2 is located on multiple sides 132; the pipe length of evaporation pipe 2 in the first sub-region of the top region is greater than the pipe length in the second sub-region of the middle region; the pipe length of evaporation pipe 2 in the third sub-region of the bottom region is less than or greater than the pipe length in the second sub-region of the middle region. The area of ​​the first sub-region is equal to the area of ​​the second sub-region, and the area of ​​the third sub-region is equal to the area of ​​the first sub-region.

[0085] The first, second, and third sub-regions are areas arbitrarily selected between the top 11 and the bottom 12. The size of the first sub-region is not a fixed value and can be selected as needed.

[0086] Evaporation pipe 2 is arranged on the surface of the shell 1 of the storage box. However, due to the distribution characteristics of heat flux density and temperature differences within the evaporation pipe, natural convection occurs in the air inside the storage box. This results in a temperature distribution within the storage box that generally decreases from top to bottom. Alternatively, due to the refrigerant flowing within the pipe, the dryness increases, and at the end, if the cooling capacity is insufficient, the temperature at the bottom may rise. Given a fixed pipe length for evaporation pipe 2 located in the same area, the contact area between the pipe and the surface of shell 1 is fixed, and the heat exchange effect is also fixed. Based on this, the pipe length of the first sub-region in the top region of evaporation pipe 2 is greater than the pipe length of the second sub-region in the middle region, and the heat exchange effect of the first sub-region in the top region of evaporation pipe 2 is better than that of the second sub-region in the middle region. Similarly, the pipe length of the third sub-region in the bottom region of evaporation pipe 2 is greater than the pipe length of the second sub-region in the middle region, and the heat exchange effect of the third sub-region in the bottom region of evaporation pipe 2 is better than that of the second sub-region in the middle region, thus improving the temperature uniformity within the storage box. When the cooling capacity is sufficient, the pipe length of the evaporator pipe 2 in the third sub-region of the bottom area is shorter than that in the second sub-region of the middle area, in order to improve the temperature uniformity inside the storage box.

[0087] In some embodiments, the ratio of the pipe length of the evaporator pipe in the second sub-region of the middle region to the pipe length of the evaporator pipe 2 in the first sub-region of the top region ranges from 0.5 to 0.9, and optionally from 0.8 to 0.9.

[0088] The pipe length ratio is determined by the specific refrigerant and refrigerant quantity, which in turn is related to the volume of the storage box, insulation technology, and system structure. Because the pressure drop and temperature difference are small in the first section of the pipe and large in the latter section, the temperature drop increases rapidly along the pipe. Therefore, a longer pipe length in the first sub-region and a shorter pipe length in the second sub-region can improve the temperature uniformity within the storage box.

[0089] In some embodiments, the pipe length of the evaporation pipe 2 in the third sub-region of the bottom region is less than the pipe length in the second sub-region of the middle region, and the ratio of the pipe length of the evaporation pipe 2 in the third sub-region of the bottom region to the pipe length of the evaporation pipe 2 in the second sub-region of the middle region ranges from 0.75 to 0.85.

[0090] Due to the flow and heat transfer characteristics of the refrigerant in the pipe, the evaporation temperature is slightly higher and the heat transfer capacity is low at the beginning of the flow. As the flow progresses, the evaporation temperature gradually decreases and the heat transfer capacity is enhanced. When the refrigerant is sufficient, the pipe length of the evaporation pipe 2 in the third sub-region of the bottom region is shorter than the pipe length in the second sub-region of the middle region, which can improve the temperature uniformity inside the shell 1.

[0091] In some embodiments, the pipe length of the evaporation pipe 2 in the second sub-region of the middle region is less than the pipe length in the third sub-region of the bottom region, and the ratio of the pipe length of the evaporation pipe 2 in the second sub-region of the middle region to the pipe length of the evaporation pipe 2 in the third sub-region of the bottom region ranges from 0.75 to 0.85.

[0092] Due to the flow and heat transfer characteristics of the refrigerant in the pipe, the evaporation temperature is slightly higher and the heat transfer capacity is lower at the beginning of the flow. As the flow progresses, the evaporation temperature gradually decreases and the heat transfer capacity is enhanced. During the flow of the refrigerant in the evaporation pipe, the dryness increases. Towards the end, if the refrigerant is insufficient, the temperature at the bottom 12 of the shell 1 may rise. The pipe length of the third sub-region of the evaporation pipe 2 in the bottom region is greater than the pipe length of the second sub-region in the middle region, which can improve the temperature uniformity inside the storage box.

[0093] In some embodiments, the pipe length of the evaporation pipe 2 in the first sub-region of the top region is greater than the pipe length of the evaporation pipe 2 in the third sub-region of the bottom region.

[0094] Due to the flow and heat transfer characteristics of the refrigerant in the pipe, the evaporation temperature is slightly higher and the heat transfer capacity is lower at the beginning of the flow. As the flow progresses, the evaporation temperature gradually decreases and the heat transfer capacity is enhanced. Therefore, the pipe length of the first sub-region in the top area of ​​the evaporation pipe 2 is greater than the pipe length of the third sub-region in the bottom area of ​​the evaporation pipe 2, which can improve the temperature uniformity in the storage box.

[0095] In some embodiments, the ratio of the pipe length of the evaporation pipe 2 in the third sub-region of the top region to the pipe length of the evaporation pipe in the first sub-region of the top region ranges from 0.6 to 0.8.

[0096] In some embodiments, along the direction from top 11 to bottom 12, the length of the evaporation pipe 2 in the second sub-region closer to top 11 in the two second sub-regions of the middle region is greater than the length of the evaporation pipe 2 in the second sub-region closer to bottom 12.

[0097] Due to the flow and heat transfer characteristics of the refrigerant in the pipe, the evaporation temperature is slightly higher and the heat transfer capacity is lower at the beginning of the flow. As the flow progresses, the evaporation temperature gradually decreases and the heat transfer capacity increases. Therefore, the length of the evaporation pipe 2 in the second sub-region near the top 11 in the two second sub-regions of the middle region is greater than the length of the evaporation pipe 2 in the second sub-region near the bottom 12.

[0098] In some embodiments, the ratio of the length of the evaporation pipe 2 in the second sub-region near the bottom 12 to the length of the evaporation pipe 2 in the second sub-region near the top 11 in the two second sub-regions of the central region ranges from 0.75 to 0.85.

[0099] In some embodiments, the evaporation pipe 2 is arranged in a reciprocating manner on multiple sides 132, and the first average spacing between adjacent pipes of the evaporation pipe 2 is less than the second average spacing, wherein the first average spacing is the average spacing between adjacent pipes of the evaporation pipe 2 in the top region, and the second average spacing is the average spacing between adjacent pipes of the evaporation pipe 2 in the middle region.

[0100] In some embodiments, the evaporation pipe 2 is arranged in a reciprocating manner on multiple sides 132, and the third average spacing between adjacent pipes of the evaporation pipe 2 is less than the second average spacing, wherein the third average spacing is the average spacing between adjacent pipes of the evaporation pipe 2 in the bottom region, and the second average spacing is the average spacing between adjacent pipes of the evaporation pipe 2 in the middle region.

[0101] In some embodiments, the distance between adjacent pipes of the evaporation pipe 2 in the same area is equal.

[0102] The shell 1 of the medical storage box can be divided into two, three, four or more compartments, each compartment being configured to hold items to be stored.

[0103] Arranging evaporation pipes 2 in the top region helps to improve the heat exchange effect of the topmost compartment in the shell 1.

[0104] Evaporation pipe 2 is arranged in the bottom area, which can improve the heat exchange effect of the compartment located at the bottom when the refrigerant is insufficient.

[0105] In some embodiments, the distance between adjacent pipes in the top region of the evaporation pipe 2 is equal to improve the temperature uniformity within the casing 1.

[0106] In some embodiments, the distance between adjacent pipes of the evaporation pipe 2 in the bottom region is equal to improve the temperature uniformity within the casing 1.

[0107] In some embodiments, the distance between adjacent pipes in the central region of the evaporation pipe 2 is equal to improve the temperature uniformity within the casing 1.

[0108] If the distance between adjacent pipes in the same area is equal, it means that the pipes in that area are evenly distributed, and the distance between adjacent pipes in that area is equal to the average distance between adjacent pipes in that area.

[0109] In the same area, the pipelines are not uniformly arranged, and there are cases where the distance between one pair of adjacent pipelines is not equal to the distance between another pair of adjacent pipelines. The average distance between adjacent pipelines in this area needs to be obtained by dividing the sum of the distances between each pair of adjacent pipelines by the total number of pairs of adjacent pipelines.

[0110] In some embodiments, the central region includes two second sub-regions, and the evaporation pipes 2 in the two second sub-regions are of equal length.

[0111] according to Figure 1 As shown in the heat distribution diagram, the maximum heat exchange occurs in the central region. Therefore, the heat exchange of the two second sub-regions located in the central region is not significantly different, and the length of the evaporation pipe 2 can be set to be equal.

[0112] The outer surface area of ​​shell 1 is large, which increases the amount of refrigerant required, and the corresponding total length of evaporation pipe 2 is long.

[0113] The evaporation pipe 2 is arranged in a reciprocating manner on multiple sides 132.

[0114] The evaporation pipe 2 includes a plurality of spaced branch pipes 21, which extend on a plurality of sides 132 and are connected to adjacent branch pipes 21 by a connecting part 22.

[0115] In some embodiments, with the multiple sides 132 extended, the branch pipe 21 extends horizontally in a straight line.

[0116] In some embodiments, the branch pipe 21 extends at an angle. The heat flux ratio can be determined simply by dividing the unfolded area at an angle and calculating the area ratio of each segment.

[0117] In some embodiments, two adjacent branch pipes 21 are parallel.

[0118] In some embodiments, the connecting portion 22 is configured as a straight line or an arc.

[0119] refer to Figure 3 The evaporation pipes 2 are located on multiple sides 132; the arrangement density of the evaporation pipes 2 in the middle region of the multiple sides 132 is less than the arrangement density of the evaporation pipes 2 in the region of the multiple sides 132 near the top 11. The middle region here refers to the middle region between the top 11 and the bottom 12.

[0120] In some embodiments, the shell 1 includes an inner liner.

[0121] In some related technologies, evaporation pipes are evenly arranged on the inner surface of the storage box with equal spacing between them. However, due to the distribution characteristics of heat flux density within the evaporation pipes and temperature differences, natural convection occurs in the air inside the storage box, resulting in a temperature distribution inside the storage box that generally decreases from top to bottom.

[0122] In this embodiment of the present disclosure, the arrangement density of the evaporation pipes 2 in the middle region of the plurality of sides 132 is less than the arrangement density of the evaporation pipes 2 in the region of the plurality of sides 132 near the top 11.

[0123] Due to the flow and heat transfer characteristics of the refrigerant within the pipes, the evaporation temperature is slightly higher and the heat transfer capacity is lower at the initial flow stage. As the flow progresses, the evaporation temperature gradually decreases, and the heat transfer capacity increases. Therefore, the arrangement density of the evaporation pipes 2 in the middle region of the multiple sides 132 is less than the arrangement density of the evaporation pipes 2 in the region near the top 11 of the multiple sides 132, which can improve the temperature uniformity within the shell 1.

[0124] In some embodiments, the evaporation pipe 2 is arranged in a reciprocating manner on multiple sides 132.

[0125] refer to Figure 2 and Figure 3 The housing 1 has a square structure. One side of the circumferential side 13 of the housing 1 is provided with a door 131, and the other three sides are provided with evaporation pipes 2. That is, the multiple sides 132 in this embodiment include a first side 132a, a second side 132b, and a third side 132c, wherein the first side 132a and the third side 132c are arranged opposite to each other, and the second side 132b is arranged opposite to the door 131.

[0126] exist Figure 3 In the unfolded diagrams of the first side 132a, the second side 132b, and the third side 132c, the evaporation pipe 2 is arranged in a reciprocating manner. The evaporation pipe 2 is arranged starting from the second side 132b and then in the following order: second side 132b → third side 132c → second side 132b → first side 132a → second side 132b → third side 132c. Finally, the evaporation pipe 2 is led out from the machine compartment at the bottom 12.

[0127] In some embodiments, the arrangement density of the evaporation pipes 2 in the middle region of the plurality of sides 132 is less than the arrangement density of the evaporation pipes 2 in the region of the plurality of sides 132 near the bottom 12.

[0128] In some related technologies, evaporator pipes are evenly arranged on the inner surface of the storage box with equal spacing between them. However, due to the distribution characteristics of heat flux density in the evaporator pipes and temperature differences, there is natural convection of air in the storage box. This results in the temperature distribution in the storage box generally decreasing from top to bottom. Alternatively, due to the refrigerant flowing in the pipes, the dryness increases, and by the time it reaches the end, the cooling capacity is insufficient, thus causing the temperature at the bottom to rise.

[0129] The arrangement density of the evaporation pipes 2 in the middle region of the plurality of sides 132 in the embodiments of this disclosure is less than the arrangement density of the evaporation pipes 2 in the region of the plurality of sides 132 near the bottom 12.

[0130] Due to the flow and heat transfer characteristics of the refrigerant within the pipes, the evaporation temperature is lowest in the later stages of the flow, but the dryness increases and the heat flux density decreases. Therefore, the arrangement density of the evaporation pipes 2 in the middle region of the multiple sides 132 is less than the arrangement density of the evaporation pipes 2 in the region near the bottom 12 of the multiple sides 132, thus improving the uniformity of temperature distribution within the shell 1.

[0131] In some embodiments, the evaporator pipe 2 is configured to allow the refrigerant within it to flow in a direction from top 11 to bottom 12.

[0132] In some embodiments, the inlet of the evaporator pipe 2 is located at the top 11, and the outlet of the evaporator pipe 2 is located at the bottom 12. Refrigerant enters the evaporator pipe 2 through the inlet and flows out through the outlet. The refrigerant within the evaporator pipe 2 flows from the top 11 to the bottom 12.

[0133] In some embodiments, the evaporation pipes 2 are also arranged uniformly or non-uniformly on the top 11.

[0134] Because of the natural convection of air inside the storage box, the temperature in the top 12 area is high. Since the top is in direct contact with the environment, the heat exchange with the environment is large. Therefore, evaporation pipes 2 are arranged in the top 11 of the shell 1 to improve the temperature uniformity inside the shell 1.

[0135] In some embodiments, the evaporation pipes 2 are evenly arranged on the top 11 of the shell 1, and the distance between adjacent pipes is equal. In this case, the bottom 12 of the shell 1 may not be arranged with evaporation pipes 2.

[0136] In some embodiments, the evaporation pipes 2 are not uniformly arranged on the top 11 of the shell 1, and the distance between adjacent pipes is not equal. In this case, the bottom 12 of the shell 1 may not be arranged with evaporation pipes 2.

[0137] In some embodiments, the evaporation pipes 2 are also arranged uniformly or non-uniformly at the bottom 12.

[0138] As the refrigerant flows through the evaporator pipe, its dryness increases, and at the end, the cooling capacity may be insufficient, causing the temperature at the bottom 12 of the casing 1 to rise. Therefore, arranging the evaporator pipe 2 at the bottom 12 of the casing 1 can improve the temperature uniformity inside the casing 1.

[0139] In some embodiments, the evaporation pipes 2 are evenly arranged at the bottom 12 of the shell 1, and the distance between adjacent pipes is equal. In this case, the top 11 of the shell 1 may not be arranged with evaporation pipes 2.

[0140] In some embodiments, the evaporation pipes 2 are not uniformly arranged at the bottom 12 of the shell 1, and the distance between adjacent pipes is not equal. In this case, the top 11 of the shell 1 may not be arranged with evaporation pipes 2.

[0141] In some embodiments, the evaporation pipes 2 are also arranged uniformly or non-uniformly at the top 11 and at the bottom 12.

[0142] Because of the natural convection of air inside the storage box, the temperature in the top 12 area is high. Also, because the refrigerant increases in dryness as it flows through the evaporator pipe, the cooling capacity is insufficient at the end, and the temperature in the bottom 12 of the shell 1 rises. Therefore, evaporator pipes 2 are arranged in both the top 11 and bottom 12 of the shell 1 to improve the temperature uniformity inside the shell 1.

[0143] In some embodiments, evaporation pipes are uniformly arranged on the top 12 of the housing 1, with equal distances between adjacent pipes, and evaporation pipes are uniformly arranged on the bottom 12 of the housing 1, with equal distances between adjacent pipes.

[0144] In some embodiments, the top 12 of the housing 1 is non-uniformly arranged with evaporation pipes, and the distance between adjacent pipes is not equal, while the bottom 12 of the housing 1 is uniformly arranged with evaporation pipes, and the distance between adjacent pipes is equal.

[0145] In some embodiments, the top 12 of the housing 1 is non-uniformly arranged with evaporation pipes, and the distance between adjacent pipes is not equal. The bottom 12 of the housing 1 is also non-uniformly arranged with evaporation pipes, and the distance between adjacent pipes is not equal.

[0146] In some embodiments, evaporation pipes are uniformly arranged on the top 12 of the housing 1, with equal distances between adjacent pipes, while evaporation pipes are non-uniformly arranged on the bottom 12 of the housing 1, with unequal distances between adjacent pipes.

[0147] In some embodiments, the distance between adjacent pipes of the evaporation pipe 2 located in the central region of the plurality of sides 132 is equal.

[0148] In some embodiments, the distance between adjacent pipes of the evaporation pipe 2 located in the region of the plurality of sides 132 near the top 11 is equal.

[0149] In some embodiments, the distance between adjacent pipes of the evaporation pipe 2 located in the region of the plurality of sides 132 near the bottom 12 is equal.

[0150] In one specific embodiment, the multiple sides 132 of the housing 1 are divided into four regions, wherein the uppermost is the top region, the two middle regions are the middle regions, and the lowermost is the bottom region. The housing 1 thus has four compartments, including one top compartment, two middle compartments, and one bottom compartment. The following provides test data for two sets of refrigerant charge amounts.

[0151] To achieve a low-temperature storage environment of -86°C, medical storage boxes often use a cascade refrigeration system, in which the high-temperature stage uses R290 refrigerant and the low-temperature stage uses R170 refrigerant.

[0152] As described in the above embodiment, the evaporator pipes 2 are arranged in a dense-sparse pattern on the inner surface of the chamber, which can improve the temperature uniformity between the various compartments. When the length ratio of the evaporator pipes attached to the inner surface of the four compartments is 6:3:3:4, the temperature distribution between different parts of the compartments according to different filling volumes is shown in the table below.

[0153] When there is sufficient refrigerant in the evaporator pipes:

[0154]

[0155] As shown in the table above, the temperature of the evaporator pipes decreases successively, and the temperature at the geometric center of the compartment also decreases successively. Assuming the set temperature is -81℃, the maximum temperature difference is 0.9℃, and the uniformity is good.

[0156] When there is insufficient refrigerant in the evaporator pipes:

[0157]

[0158] As shown in the table above, the evaporator pipe temperature begins to rise in the latter half of the process, resulting in insufficient cooling capacity. The temperature change trend at the geometric center of the compartments is similar. Assuming the set temperature is -81℃, the maximum temperature difference is 0.8℃, and the uniformity remains good.

[0159] The principle of non-uniform distribution of evaporation pipes provided in the embodiments of this disclosure will be analyzed below.

[0160] refer to Figure 1 This is a diagram showing the heat flux density and temperature distribution when the evaporation pipes are uniformly distributed along the surface of a one-dimensional shell (inner liner).

[0161] Figure 1 In the diagram, the vertical axis represents the length of the evaporation pipe, and the arrow on the vertical axis points in the same direction as the evaporation pipe from outlet to inlet. min and q max The horizontal axis represents heat flux density. min and T maxThe horizontal axis represents the temperature change inside the shell.

[0162] In the refrigeration system, the refrigerant, after being throttled and depressurized through a capillary tube, becomes a two-phase mixed working fluid. This fluid enters the evaporator and undergoes boiling heat exchange with the environment inside the storage chamber. This increases the amount of gaseous working fluid, raises its dryness fraction, and decreases its pressure along the flow path, correspondingly lowering the evaporation temperature. The temperature difference between the inlet and outlet of the evaporator pipe is mainly determined by factors such as the refrigerant's mass flow rate, pipe length, and pipe diameter. Generally, the outlet temperature of the evaporator pipe is 5℃ to 10℃ lower than the inlet temperature. Furthermore, as the proportion of the refrigerant in the gas phase increases, the flow transitions to annular flow, the working fluid velocity increases, the liquid film thins, and the liquid film's thermal resistance decreases, resulting in an increased heat transfer coefficient. However, the mass flow rate of the liquid working fluid decreases. Therefore, the cooling capacity is highest at a certain point in the middle of the evaporator pipe, with its heat flux density roughly distributed as follows: Figure 1 The first curve S1 is shown in the figure. The first curve S1 mainly represents the change of heat flux density along the evaporation pipe, which can illustrate the influence of heat flux density on the temperature distribution in the storage box and provide a basis for the layout of the evaporation pipe.

[0163] Assuming the evaporator pipes are uniformly distributed across the shell surface, and the refrigeration system operates stably, the regional temperature is in dynamic equilibrium. If there is no natural convection caused by the sinking of cold air, the temperature variation along the shell surface from top to bottom follows the same trend as the heat flux density variation; that is, the temperature distribution first decreases and then increases from top to bottom. Figure 1 As shown in the second curve S2, the second curve S2 mainly represents the temperature change in the storage box without natural convection. The temperature distribution in the storage box is similar to the heat flux density distribution of the refrigerant along the evaporator pipe.

[0164] However, in reality, due to the lower temperature and increased air density in the upper part of the region, cold air sinks, causing natural air convection in the region. This changes the temperature trend from top to bottom from initially decreasing and then increasing to decreasing sequentially. For example... Figure 1 As shown in the third curve S3, the third curve S3 mainly represents the temperature change in the storage box due to natural convection. This means that the temperature distribution is affected not only by the heat flux density of the refrigerant along the evaporator pipe, but also by natural convection.

[0165] Therefore, heat flux density and natural convection can affect the temperature uniformity within the storage chamber.

[0166] refer to Figure 3If the storage box is divided into four areas from top to bottom (in reality, three or five areas can be set, and the number of areas is unlimited; this is just an example for illustration), they are area D1, area D2, area D3, and area D4. Area D1 belongs to the top area, area D2 and area D3 belong to the middle area, and area D4 belongs to the bottom area.

[0167] When the influence of natural convection on temperature distribution is greater than the influence of heat flux density in the evaporator pipe on temperature distribution, the temperature distribution at the geometric center of the region is roughly: temperature of the first region > temperature of the second region > temperature of the third region > temperature of the fourth region. However, when the influence of natural convection on temperature distribution is less than the influence of heat flux density in the evaporator pipe on temperature distribution, the temperature distribution at the geometric center of the region may become: temperature of the first region > temperature of the second region > temperature of the third region < temperature of the fourth region (when the cooling capacity is insufficient, the sinking of cold air caused by natural convection cannot make up for the missing cooling capacity, and the temperature of the fourth region will be higher than the temperature of the third region), that is, the temperature in the lower region is higher than that in the middle region.

[0168] Meanwhile, in the initial system design phase, the diameter and total length of the evaporation pipes were determined based on the operating parameters. Therefore, it was only necessary to optimize the layout of the evaporation pipes on the shell surface to reduce the temperature difference between areas, thereby improving the temperature uniformity within the storage chamber.

[0169] From the above analysis, it can be seen that when the temperature distribution inside the storage chamber decreases sequentially, the evaporation pipes follow a distribution pattern of denser pipes at the top and sparser pipes at the bottom. Conversely, when the temperature inside the storage chamber rises slightly at the bottom, the evaporation pipes follow a distribution pattern of denser pipes at the top, sparser pipes in the middle, and denser pipes at the bottom. Figure 3 As shown.

[0170] If the refrigerant at the outlet of the evaporator pipe is not overheated, it indicates that the cooling capacity is always sufficient. In this case, the evaporator pipe usually follows a distribution pattern of denser refrigerant at the top and sparser refrigerant at the bottom.

[0171] The arrangement of evaporation pipes provided in this embodiment is mainly based on the calculation of the temperature distribution law along the pipe in the two-phase flow pressure drop formula. After simplification and assumptions, the number of evaporation pipes arranged in each region is obtained.

[0172] In some embodiments, the method for arranging the evaporation pipes of the medical storage box includes the following steps: dividing multiple sides of the shell of the medical storage box into n regions along the direction from top to bottom according to a preset area ratio;

[0173] The heat flux of each region is obtained based on the wall temperature of the shell in each region, the geometric mean temperature of the refrigerant in the evaporator pipes in each region when evaporator pipes are arranged, and the contact area between the evaporator pipes and the wall in each region.

[0174] Based on the fact that the heat flux ratio of each region is the same as the preset area ratio, the ratio of the contact area between the evaporation pipe and the shell wall of two adjacent regions is obtained.

[0175] Based on the ratio of the contact area between the evaporation pipes and the shell wall of two adjacent regions, the length of the evaporation pipes that should be arranged in each region is obtained.

[0176] Evaporation pipes of corresponding length are laid out in each area.

[0177] In some embodiments, n takes a value greater than or equal to 2.

[0178] In some embodiments, the evaporation pipes are arranged in a reciprocating manner on multiple sides of the housing.

[0179] In some embodiments, arranging evaporation pipes of corresponding length in each region includes: uniformly distributing evaporation pipes of corresponding length in each region by zigzagging back and forth within that region. Optionally, the distance between two adjacent evaporation pipes located in the same region is equal.

[0180] In some embodiments, obtaining the heat flux of each region includes: according to Q i =hA i (t wi -t eqvi Obtain the heat flux for each region;

[0181] Among them, Q i Let be the heat flux of the i-th region;

[0182] h is the local heat transfer coefficient of the boiling flow inside the evaporation pipe;

[0183] A i Let be the contact area between the evaporation pipe and the shell wall in the t-th region;

[0184] t wi Let be the wall temperature of the shell in the i-th region;

[0185] t eqvi Let be the geometric mean temperature of the refrigerant in the evaporator pipe within the i-th region;

[0186] The value of i is [1, n].

[0187] In some embodiments, obtaining the ratio of the contact area between the evaporator pipe and the shell wall of two adjacent regions, based on the fact that the ratio of the heat flux of each region is the same as the preset area ratio, includes according to... get:

[0188]

[0189] in,

[0190] Q i+1 Let be the heat flux of the (i+1)th region;

[0191] A i+1 Let be the contact area between the evaporation pipe and the wall of the shell in the (i+1)th region;

[0192] t w(i+1) Let be the wall temperature of the shell in the (i+1)th region;

[0193] t eqv(i+1) Let be the geometric mean temperature of the refrigerant in the evaporator pipe within the (i+1)th region;

[0194] Let a be the area of ​​the i-th region. i The area a of the (i+1)th region i+1 The ratio of .

[0195] At this point, the maximum value of i is n-1.

[0196] In some embodiments, where t wi and t w(i+1) All are set values, and t wi =t w(i+1) Under the premise of ensuring uniform temperature inside the insulation box, the wall temperature of each area of ​​the shell is the same and consistent with the temperature inside the shell, which is the user's set temperature value.

[0197] In some embodiments, determining the length of the evaporation pipe to be arranged in each region based on the ratio of the contact area between the evaporation pipe and the wall of the shell in two adjacent regions includes:

[0198] The ratio of the evaporation pipe lengths of two adjacent regions is obtained by comparing the contact area between the evaporation pipes and the shell wall of two adjacent regions. The length of the evaporation pipe for each region is obtained by comparing the evaporation pipe lengths of two adjacent regions and the total length of the evaporation pipes.

[0199] The contact area between the evaporator pipe per unit length and the shell wall can be obtained based on the pipe diameter. The pipe diameter is a known parameter.

[0200] In some embodiments, the geometric mean temperature t of the refrigerant within the evaporator pipe in any region eqv for in,

[0201] t eq (x) represents the friction temperature distribution within the evaporation pipe, which is obtained based on the friction pressure distribution P(x) within the evaporation pipe.

[0202] x is the length of the evaporation pipe in this area; x = x2 - x1;

[0203] x1 is the starting length of the evaporation pipe in this area;

[0204] x2 represents the length of the evaporation pipe at the end of the pipe in this area.

[0205] In some embodiments, the friction pressure distribution P(x) of the evaporation pipe is obtained based on the inlet pressure of the evaporation pipe and the friction pressure drop ΔP within the evaporation pipe.

[0206] In some embodiments, the friction drop ΔP in the evaporation pipe is obtained based on the pressure drop of the liquid single-phase flow straight pipe and the pressure drop of the gas single-phase flow straight pipe in the evaporation pipe.

[0207] In some embodiments, the pressure drop along the evaporation pipe is...

[0208] Among them, the conversion factor

[0209] A1, A2, A3, and A4 are all constants;

[0210]

[0211] ΔP l For single-phase liquid refrigerant flow, the pressure drop in the straight pipe is considered.

[0212] ΔP g The pressure drop in a straight pipe for single-phase refrigerant gas flow.

[0213] In some embodiments, the pressure drop in a single-phase liquid flow straight pipe is... Among them, friction coefficient Reynolds number Liquid phase conversion rate

[0214] In the formula, V ol G represents the liquid phase reduced velocity. l ρ is the liquid phase flow rate; l U is the liquid phase density; ldenoted as ρ, where A is the viscosity of the liquid phase; D is the inner cross-sectional area of ​​the evaporation pipe; and L is any length of the evaporation pipe.

[0215] In some embodiments, the pressure drop in a single-phase gas flow straight pipe is... Among them, friction coefficient Reynolds number Gas phase conversion rate

[0216] In the formula, V og G represents the gas phase reduced velocity. g ρ is the gas phase flow rate; g U is the gas phase density; g denoted as V0, where A is the viscosity of the gas phase; D is the inner cross-sectional area of ​​the evaporation pipe; and L is any length of the evaporation pipe.

[0217] Since there are many formulas for the pressure drop of two-phase flow, most of which are empirical formulas, this invention is not limited to the two-phase flow pressure drop formulas provided in the above embodiments of this disclosure.

[0218] This disclosure addresses the problem of uneven temperature distribution within the storage chamber caused by the decreasing evaporation temperature along the evaporator flow path, natural air convection, and sinking of cold air. A storage chamber with non-uniformly distributed evaporation pipes is proposed. Based on the temperature variation pattern along the evaporation pipes, a functional relationship is established between the number of pipes in each region and the temperature distribution within the pipes. The non-uniform arrangement of the evaporation pipes improves the uniformity of regional temperature distribution.

[0219] The specific distribution pattern is analyzed as follows:

[0220] When the refrigeration system is in a stable operating state, the evaporator's cooling capacity and the heat load inside the storage box establish a dynamic balance.

[0221] The heat exchange formula between refrigerant cooling capacity and heat load inside the storage box is: Q 潜 =qm(h2-h1)=Q 传热 =qA=hA(t) w -t eqv ).

[0222] In the formula, Q 潜 Latent heat of refrigerant;

[0223] qm is the mass flow rate of liquid refrigerant;

[0224] h2-h1 is the specific enthalpy difference of the liquid refrigerant, h1 is the inlet enthalpy value within the micro-element, and h2 is the outlet enthalpy value within the micro-element;

[0225] Q 传热 The heat flux within the evaporator pipe is expressed in kW.

[0226] q is the heat flux density inside the evaporator pipe, in kW·m -2 ;

[0227] h is the local heat transfer coefficient of the boiling flow inside the evaporation pipe, in kW·m³. -2 ·K -1 ;

[0228] A is the contact area between the evaporator pipe and the inner liner, in meters. 2 ;

[0229] t w The local wall temperature of the shell, in °C.

[0230] t eqv The geometric mean temperature of the mixed working fluid inside the evaporation pipe is ℃.

[0231] For a pure working fluid, its equilibrium temperature is the saturation temperature. Since the pipe diameter, total length, refrigerant mass flow rate, and working fluid of the evaporator pipe are fixed, the pressure drop of the two-phase flow inside the circular pipe can be calculated using a semi-empirical formula. Assuming the gas-liquid two-phase flow is either a single-phase gas flow or a single-phase liquid flow, the resistance drop of the single-phase refrigerant pipe is first calculated, and then corrected according to the relevant flow pattern resistance drop correction formula, i.e., the Hart-Martinelli method.

[0232] Pressure drop in a straight pipe for single-phase liquid flow: Among them, friction coefficient Reynolds number Liquid phase conversion rate

[0233] Pressure drop in a straight pipe for single-phase gas flow: Among them, friction coefficient Reynolds number Gas phase conversion rate

[0234] In the formula, V ol The velocity is the liquid phase reduced velocity, in m / s;

[0235] G l The value is the liquid phase flow rate, kg / h;

[0236] ρ l The density of the liquid phase is kg / m³. 3 ;

[0237] u l The viscosity is expressed in Pa·s.

[0238] V og For gas phase conversion velocity;

[0239] G g Gas phase flow rate, kg / h;

[0240] ρ g The density is in the gas phase, kg / m³ 3 ;

[0241] u g The viscosity is expressed in Pa·s.

[0242] A is the inner cross-sectional area of ​​the evaporation pipe, in meters. 2 ;

[0243] D is the diameter of the evaporation pipe;

[0244] L represents any length of the evaporation pipe.

[0245] Mattinelli's parametric formula Conversion factor A1, A2, A3, and A4 are all constants, and their values ​​can be obtained from the table of regression coefficients for four combinations of gas-liquid two-phase flow. Pressure drop in the evaporator pipe. Given the inlet pressure of the pipeline, the total pressure drop can be calculated, and the total temperature drop of the refrigerant at the inlet and outlet of the pipeline can be obtained.

[0246] To simplify the calculation process, some assumptions are made:

[0247] 1. The change in heat flux density within the evaporation pipe and the temperature distribution within the storage chamber interact. To improve temperature uniformity, it is necessary to control the heat flux Q to be equal in each region and the wall temperature t of the shell in each region. w Equal, for example: multiple sides of the shell are divided into four regions, namely Q1:Q2:Q3:Q4 = a1:a2:a3:a4, t w1 =t w2 =t w3 =t w4 At this time, there is no natural convection inside the storage box.

[0248] 2. The local heat transfer coefficient h of the boiling flow inside the evaporation pipe is taken from the outer surface of the evaporation pipe, so h remains the same and is a constant value.

[0249] 3. The temperature difference between the inner and outer surfaces of the evaporator pipe is not considered, and it is assumed that the temperature of the outer surface of the evaporator pipe is the same as that of the inner surface of the evaporator pipe.

[0250] 4. When the system is in a stable state, it is assumed that the cooling capacity is mainly used to balance the heat loss of the storage box. That is, when the diameter and total length of the evaporator pipe are fixed, the inlet and outlet temperatures of the evaporator pipe are constant.

[0251] 5. Since the top and bottom areas of the storage box account for a small proportion of the total surface area of ​​the shell, the layout calculation of the evaporation pipes at the top and bottom is not considered here.

[0252] After simplification, the inlet pressure of the evaporator pipe is known. The pressure distribution along the evaporator pipe, P(x), can be calculated using the two-phase flow pressure drop formula (where L is a variable, and the interval is from the inlet to the outlet of the evaporator pipe, thus obtaining the pressure variation along the pipe). This is the refrigerant evaporation pressure P. s (x).

[0253] For a specific refrigerant, the evaporation pressure P s With evaporation temperature t eq Following relation P s =f(t) eq (For each refrigerant, there is a one-to-one correspondence between saturation temperature and saturation pressure, which can be obtained by referring to tables and graphs.) Based on the relevant saturation pressure (i.e., evaporation pressure P) s ) and saturation temperature (i.e., evaporation temperature t) eq The relationship diagram or the software REFPROP can be used to obtain the temperature distribution t along the evaporator pipe. eq (x) (Temperature and pressure are in one-to-one correspondence; since the pressure variation along the pipe has been calculated, the temperature variation along the pipe can be derived accordingly), thus the geometric mean temperature within a section of the pipe can be calculated. In some embodiments, the evaporation pipe is divided into four sections, where x1 and x2 are the beginning (starting length value) and end (ending length value) of each section, respectively. The beginning of one section is the end of the previous section, and the end of one section is the beginning of the next section. The beginning of the first section is the inlet of the evaporation pipe, i.e., x1 is 0.

[0254] for Figure 3 In the four regions shown, since Q1:Q2:Q3:Q4 = 1:1:1:1:, h1 = h2 = h3 = h4 (the local heat transfer coefficients of the flow boiling within the evaporation pipes are the same in all four regions), t w1 =t w2 =t w3 =t w4 And since the unit pipe length has the same contact area with the inner liner surface, then L1(t) w1 -t eqv1 )=L2(t w2 -t eqv2 )=L3(t w3 -t eqv3 )=L4(t w4 -t eqv4 Based on this equation, the proportional relationship L1:L2:L3:L4 can be calculated, and the total length L of the evaporation pipe can be determined. 总 Given this, the length of the evaporation pipes arranged in each area can be obtained.

[0255] In some embodiments, the shell of the medical storage box can be divided into n regions along the direction from top to bottom according to a preset area ratio, and the heat flux relationship of each region also satisfies the above-mentioned preset ratio. For example, a1:a2:a3:a4 = 1:1.3:1.5:2, then Q1:Q2:Q3:Q4 = 1:1.3:1.5:2.

[0256] The outer surface area of ​​shell 1 is large, which increases the amount of refrigerant required, and the corresponding total length of evaporation pipe 2 is long.

[0257] The refrigeration system is stable, and the cooling capacity equals the heat loss, meaning the system's cooling capacity is dynamically balanced with the heat load inside the storage box. The heat loss is related to the temperature inside the storage box, the ambient temperature, and the insulation technology used in the storage box. w -t eqv = Heat leakage, h is known, the area A of the inner liner per unit pipe length is known, t w Set the temperature for the storage box, i.e. The total length of the pipeline can be determined from this.

[0258] To improve the uniformity of temperature distribution within the preservation chamber, this disclosure provides a preservation chamber with non-uniformly distributed evaporation pipes. Furthermore, it provides a method for arranging the evaporation pipes based on the temperature variation along the evaporator, thereby improving the uniformity of temperature within the preservation chamber and enhancing the reliability of sample preservation. Moreover, this disclosure only changes the layout of the evaporation pipes without incurring additional costs.

[0259] Based on the embodiments disclosed above, in the absence of explicit denial or conflict, the technical features of one embodiment may be advantageously combined with one or more other embodiments.

[0260] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. A medical storage box, characterized in that, include: The housing (1) includes a top (11), a bottom (12) and a circumferential side (13), the circumferential side (13) being composed of a door (131) and a plurality of side surfaces (132), the plurality of side surfaces (132) being divided into a top region, a middle region and a bottom region along the direction from the top (11) to the bottom (12); as well as An evaporator pipe (2) is provided on the plurality of sides (132) and configured such that the refrigerant therein flows in a direction from the top (11) to the bottom (12); the pipe length of the evaporator pipe (2) in a first sub-region of the top region is greater than the pipe length of the second sub-region of the middle region; the pipe length of the evaporator pipe (2) in a third sub-region of the bottom region is greater than the pipe length of the second sub-region of the middle region; the area of ​​the first sub-region is equal to the area of ​​the second sub-region, and the area of ​​the first sub-region is equal to the area of ​​the third sub-region.

2. The medical storage box as described in claim 1, characterized in that, The ratio of the length of the evaporation pipe in the second sub-region to the length of the evaporation pipe (2) in the first sub-region is in the range of 0.5 to 0.

9.

3. The medical storage box as described in claim 1, characterized in that, The length of the evaporation pipe (2) in the second sub-region is less than the length of the pipe in the third sub-region, and the ratio of the length of the evaporation pipe (2) in the second sub-region to the length of the evaporation pipe (2) in the third sub-region is in the range of 0.75 to 0.

85.

4. The medical storage box as described in claim 1, characterized in that, The length of the evaporation pipe (2) in the first sub-region is greater than the length of the evaporation pipe (2) in the third sub-region.

5. The medical storage box as described in claim 4, characterized in that, The ratio of the length of the evaporation pipe (2) in the third sub-region to the length of the evaporation pipe in the first sub-region is in the range of 0.6 to 0.

8.

6. The medical storage box as described in claim 1, characterized in that, Along the direction from the top (11) to the bottom (12), the length of the evaporation pipe (2) in the second sub-region near the top (11) of the two second sub-regions of the middle region is greater than the length of the evaporation pipe (2) in the second sub-region near the bottom (12).

7. The medical storage box as described in claim 6, characterized in that, The ratio of the length of the evaporation pipe (2) in the second sub-region near the bottom (12) to the length of the evaporation pipe (2) in the second sub-region near the top (11) in the middle region is between 0.75 and 0.

85.

8. The medical storage box as described in any one of claims 1 to 7, characterized in that, The evaporation pipe (2) is arranged in a back-and-forth manner on the multiple sides (132). The first average spacing between adjacent pipes of the evaporation pipe (2) is less than the second average spacing. The first average spacing is the average spacing between adjacent pipes of the evaporation pipe (2) in the top region, and the second average spacing is the average spacing between adjacent pipes of the evaporation pipe (2) in the middle region.

9. The medical storage box as described in any one of claims 1 to 7, characterized in that, The evaporation pipe (2) is arranged in a back-and-forth manner on the multiple sides (132), and the third average spacing between adjacent pipes of the evaporation pipe (2) is less than the second average spacing. The third average spacing is the average spacing between adjacent pipes of the evaporation pipe (2) in the bottom region, and the second average spacing is the average spacing between adjacent pipes of the evaporation pipe (2) in the middle region.

10. The medical storage box as described in any one of claims 1 to 7, characterized in that, The evaporation pipe (2) is also evenly arranged at the top (11), and / or the evaporation pipe (2) is also evenly arranged at the bottom (12).

11. The medical storage box as described in any one of claims 1 to 7, characterized in that, The central region includes two second sub-regions, and the evaporation pipes (2) in the two second sub-regions are of equal length.

12. A method for arranging the evaporation pipes of a medical preservation box according to any one of claims 1 to 11, comprising the following steps: The shell of the medical storage box is divided into n areas along the direction from top to bottom according to a preset area ratio. The heat flux of each region is obtained based on the wall temperature of the shell in each region, the geometric mean temperature of the refrigerant in the evaporator pipes in each region when evaporator pipes are arranged, and the contact area between the evaporator pipes and the wall in each region. Based on the fact that the heat flux ratio of each region is the same as the preset area ratio, the ratio of the contact area between the evaporation pipe and the shell wall of two adjacent regions is obtained. Based on the ratio of the contact area between the evaporation pipes and the shell wall of two adjacent regions, the length of the evaporation pipes that should be arranged in each region is obtained. Evaporation pipes of corresponding length are laid out in each area.

13. The method for arranging the evaporation pipes of the medical preservation box as described in claim 12, wherein, Arranging evaporation pipes of corresponding length in each area includes: evenly distributing evaporation pipes of corresponding length in each area by folding them back and forth within that area.

14. The method for arranging the evaporation pipes of the medical preservation box as described in claim 12, wherein, Obtaining the heat flux for each region includes: based on Obtain the heat flux for each region; in, For the first Heat flux of each region; The heat transfer coefficient for local boiling within the evaporator pipe; For the first The contact area between the evaporator pipe and the shell wall within each region; For the first The wall temperature of the shell within each region; For the first The geometric mean temperature of the refrigerant in the evaporator pipes within each region; The value of is [1, n].

15. The method for arranging the evaporation pipes of the medical preservation box as described in claim 14, wherein, Based on the fact that the heat flux ratio of each region is the same as the preset area ratio, the proportional relationship between the contact area of ​​the evaporation pipe and the shell wall of two adjacent regions is obtained, including: according to ,get: in, For the first Heat flux of each region; For the first The contact area between the evaporator pipe and the shell wall within each region; For the first +1 area of ​​shell wall temperature; For the first The geometric mean temperature of the refrigerant in the evaporator pipes within each region; For the first Area of ​​each region With the Area of ​​each region The ratio of .

16. The method for arranging the evaporation pipes of the medical preservation box as described in claim 15, wherein, and All are set values, and .

17. The method of manufacturing a medical storage box according to any one of claims 12 to 16, wherein, Based on the proportional relationship between the contact area between the evaporator pipes and the shell wall of two adjacent regions, the length of the evaporator pipes to be arranged in each region is obtained, including: The ratio of the evaporation pipe lengths of two adjacent regions is obtained by the ratio of the contact area between the evaporation pipes and the shell wall of two adjacent regions. The evaporation pipe length of each region is obtained by the ratio of the evaporation pipe lengths of two adjacent regions and the total length of the evaporation pipes.

18. The method for arranging the evaporation pipes of the medical preservation box as described in any one of claims 12 to 16, wherein, Geometric mean temperature of refrigerant in the evaporator pipe of any region for: ,in, The temperature distribution along the evaporator pipe is determined by the pressure distribution along the evaporator pipe. get; This refers to the length of the evaporation pipes in this area; - ; This represents the length of the starting end of the evaporation pipe in this area. This is the numerical value for the end length of the evaporation pipe in this area.

19. The method for arranging the evaporation pipes of the medical preservation box as described in claim 18, wherein, Based on the inlet pressure of the evaporation pipe and the pressure drop along the pipe. Obtain the pressure distribution along the pipe. .

20. The method for arranging the evaporation pipes of the medical preservation box as described in claim 19, wherein, The pressure drop along the evaporation pipe It is obtained from the pressure drop of the single-phase liquid flow straight pipe and the pressure drop of the single-phase gas flow straight pipe in the evaporation pipeline.

21. The method for arranging the evaporation pipes of the medical preservation box as described in claim 20, wherein, Pressure drop along the evaporator pipe , Among them, the conversion factor , , , and All are constants; For pressure drop in a straight pipe for single-phase liquid flow; This refers to the pressure drop in a straight pipe for single-phase gas flow.

22. The method for arranging the evaporation pipes of the medical preservation box as described in claim 20 or 21, wherein, Pressure drop in straight pipe for single-phase liquid flow ,in, Friction coefficient Reynolds number Liquid phase reduced velocity ; In the formula, For liquid phase conversion velocity; This refers to the liquid phase flow rate; The density of the liquid phase; This refers to the viscosity of the liquid phase. This is the inner cross-sectional area of ​​the evaporator pipe; The diameter of the evaporator pipe; Let be any length of the evaporation pipe.

23. The method for arranging the evaporation pipes of the medical preservation box as described in claim 20 or 21, wherein, Pressure drop in single-phase gas flow straight pipe ,in, Friction coefficient Reynolds number Gas phase conversion velocity ; In the formula, For gas phase conversion velocity; This refers to the gas phase flow rate; This refers to the gas phase density. This refers to the viscosity of the gas phase. This is the inner cross-sectional area of ​​the evaporator pipe; The diameter of the evaporator pipe; Let be any length of the evaporation pipe.

Images