KR102588870B1 - Refrigerator for super-freezing a storing chamber - Google Patents

Abstract

The present invention includes a case including a storage space cooled to ultra-low temperature using a refrigeration cycle containing a mixed refrigerant; an inlet provided in the case to communicate with the storage space; an external door rotatably provided on the case to open and close the inlet; A gasket provided on the outer door to seal between the outer door and the inlet; A cryogenic refrigerator can be provided that includes an internal door provided inside the storage space to partition the storage space.

Description

Ultra-low temperature refrigerator {Refrigerator for super-freezing a storing chamber}

The present invention relates to ultra-low temperature refrigerators.

The refrigerator may include a case that forms the exterior, a storage compartment provided inside the case to store items, a door that opens and closes the storage compartment, and a cooling unit that implements a refrigeration cycle to cool the storage compartment.

A general home refrigerator may have a storage compartment with at least one of a refrigerating compartment that creates an internal environment at a temperature lower than room temperature or around 0°C, and a freezer compartment that creates an internal environment with a temperature below zero, which is lower than the temperature of the refrigerator compartment. In this case, the temperature of the freezer is generally set to be lower than -30°C.

Meanwhile, an ultra-low temperature refrigerator creates an internal environment at a temperature lower than the temperature of the freezer compartment provided in a home refrigerator. In this case, the storage compartment can be an extremely low temperature environment of -60°C to -80°C or lower.

However, because the temperature difference between the internal temperature and the external temperature of the ultra-low temperature refrigerator is large, a large negative pressure is generated when the door is opened and closed, causing a problem in that the door cannot be opened for a certain period of time.

In other words, when the door is opened and the stored items inside the storage room are taken out, outside air flows into the storage room, and when the door is closed, the inflowing outside air is momentarily condensed by the ultra-low temperature storage room, creating negative pressure inside the storage room. Therefore, it requires so much force that an ordinary adult male cannot open it, and it takes several minutes for the negative pressure inside the storage compartment to be released, causing discomfort to the user.

In order to solve the above-mentioned problem, the following issues are addressed.

The object of the present invention is to provide a refrigerator that does not require much force to open the door even if negative pressure is generated inside the storage compartment when the door is reopened after opening and closing.

The object of the present invention is to provide a refrigerator that minimizes the negative pressure generated on the bottom of the door when the door is opened and closed and then reopened.

In order to solve the above-described problem, the present invention includes a case including a storage space cooled to ultra-low temperature using a refrigeration cycle containing a mixed refrigerant; an inlet provided in the case to communicate with the storage space; an external door rotatably provided on the case to open and close the inlet; A gasket provided on the outer door to seal between the outer door and the inlet; A cryogenic refrigerator can be provided that includes an internal door provided inside the storage space to partition the storage space.

The storage space may include a first space formed by the inner door and the outer door, and a second space where storage items are stored and whose volume is larger than the first space.

The first space and the second space may be provided to allow air flow.

A storage space cooled to ultra-low temperatures may be characterized as being cooled to a lower temperature than the freezer compartment of a general household refrigerator.

The case includes a first guider extending from the inner peripheral surface of the storage space to the inside of the storage space, and a second guider extending further than the first guider, and the inner door is a first guider sliding on the first guider. It may include an inner door and a second inner door sliding on the second guider.

The sum of the cross-sectional areas of the first inner door and the second inner door may be larger than the cross-sectional area of the inlet.

The width of the second inner door may be longer than that of the first inner door.

It may include an inner door handle recessed in an upper surface of the first inner door or the second inner door.

The inner door includes a transparent member through which the storage space can be viewed, and an inner door frame provided around the transparent member, and the inner door frame may include a plurality of first reinforcing ribs provided in a longitudinal direction. there is.

Meanwhile, the present invention includes an inner door hinge that rotatably connects the inner door; A cryogenic refrigerator may be provided, comprising an opening delay unit that interlocks the outer door and the inner door to open the inner door a predetermined time after the outer door is opened.

In addition, according to the present invention, the case includes a fourth guider extending from the inner peripheral surface of the storage space, a shutter insertion hole communicating with the inside of the case above the fourth guider, and the inner door is connected to the fourth guider. It is possible to provide a cryogenic refrigerator characterized in that the storage space is divided by a shutter that slides from above and is inserted into the shutter insertion hole.

In addition, according to the present invention, the case includes a fifth guider extending from the inner peripheral surface of the storage space, the inner door is supported on the upper surface of the fifth guider, and a third inner door is rotatably connected to the inside of the storage space. A cryogenic refrigerator can be provided, which includes a door and a fourth inner door that is rotatably mounted on the third inner door 620 and has a free end.

The mixed refrigerant may be comprised of a high-temperature refrigerant having a first boiling point and a low-temperature refrigerant having a second boiling point lower than the first boiling point.

The mixed refrigerant is a high-temperature refrigerant selected from the group consisting of isopentane, 1,2-butadiene, butane (N-Butane), 1-butene, and isobutane. Additionally, the low-temperature refrigerant may be comprised of a combination of one of ethane and ethylene.

The refrigeration cycle is connected by a refrigerant pipe in the order of a compressor, condenser, expansion device, and evaporator, and the refrigerant pipe includes a condensation pipe extending from the outlet of the condenser to the expansion device, and a suction pipe extending from the outlet of the evaporator to the compressor. It includes a first heat exchanger in which heat exchange occurs between the refrigerant flowing in the condensation pipe and the refrigerant flowing in the suction pipe, and a second heat exchanger in which heat exchange occurs between the refrigerant flowing in the expansion device and the refrigerant flowing in the suction pipe. It can be characterized as:

Based on the flow direction of the refrigerant flowing through the suction pipe, the first heat exchanger may be provided at the outlet side of the second heat exchanger.

The present invention has the effect of providing a refrigerator that does not require much force to open the door even if negative pressure is generated inside the storage compartment when the door is reopened after opening and closing.

The present invention has the effect of providing a refrigerator that minimizes the negative pressure generated on the bottom of the door when the door is opened and closed and then reopened.

1 is a perspective view of the ultra-low temperature refrigerator of the present invention.
FIG. 2 is a diagram illustrating a cryogenic refrigerator with the door closed in a cross section taken along line AA′ of FIG. 1 .
FIG. 3 is a diagram illustrating a cryogenic refrigerator with the door closed in a cross section taken along line BB′ of FIG. 1 .
Figure 4 is a diagram showing a first embodiment of the inner door provided in the ultra-low temperature refrigerator of the present invention.
Figure 5 is a bottom view of the first inner door or the second inner door provided in the ultra-low temperature refrigerator of the present invention.
Figure 6 is a diagram showing an exploded perspective view of the first inner door or the second inner door provided in the ultra-low temperature refrigerator of the present invention.
FIG. 7A is a cross-sectional view taken along line CC′ of FIG. 5.
FIG. 7B is a cross-sectional view taken along line DD′ of FIG. 5.
Figure 8 is a diagram showing a second embodiment of the inner door provided in the ultra-low temperature refrigerator of the present invention.
Figure 9 is a diagram showing a third embodiment of the inner door provided in the ultra-low temperature refrigerator of the present invention.
Figure 10 is a diagram showing a fourth embodiment of the inner door provided in the ultra-low temperature refrigerator of the present invention.
FIG. 11 is a cross-sectional view of EE′ in FIG. 1.
Figure 12 is a diagram showing a first embodiment of a cooling unit that can be provided in the ultra-low temperature refrigerator of the present invention.
Figure 13 is a diagram showing a second embodiment of a cooling unit that can be provided in the ultra-low temperature refrigerator of the present invention.
Figure 14 is a diagram showing a third embodiment of a cooling unit that can be provided in the ultra-low temperature refrigerator of the present invention.
Figure 15 is a diagram showing a fourth embodiment of a cooling unit that can be provided in the ultra-low temperature refrigerator of the present invention.
Figure 16 is a diagram showing a fifth embodiment of a cooling unit that can be provided in the ultra-low temperature refrigerator of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The configuration or control method of the device described below is only for explaining the embodiments of the present invention and is not intended to limit the scope of the present invention, and the same reference numbers used throughout the specification indicate the same components. .

Unless otherwise specified, all terms in this specification have the same general meaning as understood by those skilled in the art, and if a term used in this specification conflicts with the general meaning of the term, the definition used in this specification It follows.

Referring to the Cartesian coordinate system shown in Figure 1, the positive direction of the X-axis is forward, the negative direction of the , The negative direction of the Y axis is defined as left.

1 is a perspective view of the ultra-low temperature refrigerator of the present invention. Hereinafter, the ultra-low temperature refrigerator of the present invention will be described with reference to FIG. 1.

The ultra-low temperature refrigerator of the present invention includes a case 100 including a storage space 150 cooled to ultra-low temperature, an inlet 122 provided in the case 100 to communicate with the storage space 150, and an inlet 122. It may include an external door 200 that is rotatably provided on the case 100 to open and close it.

Case 100 includes an outer case 110 that forms the exterior of a cryogenic refrigerator, an inner case 130 that is provided inside the outer case 110 and forms a storage space 150, and an outer case 110. It may include a cover case 120 connecting between and the inner case 130.

However, the cover case 120 may be made of a single member extending from the outer case 110.

FIG. 2 is a diagram illustrating a cryogenic refrigerator with the door closed in a cross section taken along line A-A′ of FIG. 1 . FIG. 3 is a diagram illustrating a cryogenic refrigerator with the door closed in a cross section taken along line B-B′ of FIG. 1 . Figure 4 is a diagram showing a first embodiment of the inner door provided in the ultra-low temperature refrigerator of the present invention.

Referring to FIG. 2, the external case 110 may be provided in the shape of a rectangular parallelepiped. The outer case 110 may be open on one side to communicate with the interior, and may include an outer opening 112 into which the cover case 120 is inserted and fixed. The outer case 110 and the cover case 120 may be made of plastic, and are preferably made of ABS.

The inner case 130 is provided inside the outer case 110 and forms a storage space 150 therein.

The storage space 150 is a space in which items can be stored, and an environment cooled to a very low temperature can be formed. Ultra-low temperature is a temperature that is cooled to a temperature lower than the temperature inside the freezer of a general home refrigerator. For example, cryogenic temperatures can be temperatures below -60°C.

The inner case 130 may include an inner opening 132 that communicates with the outer opening 112 and allows stored objects to enter and exit. The inner case 130 may be made of a metal material with good thermal conductivity, and in the present invention, it is preferably made of aluminum.

The cover case 120 can seal the internal space 140 provided between the external case 110 and the internal case 130 by connecting the external opening 112 and the internal opening 132. In other words, the internal space 140 may be formed by the external case 110, the internal case 130, and the cover case 120.

In the present invention, the outer opening 112 is provided on the upper side of the outer case 110, the inner opening 132 is provided on the upper side of the inner case 130, and the cover case 120 is provided between the outer case 110 and the inner case. The upper end of the case 130 can be connected.

The cover case 120 includes an internal opening 132 and an inlet 122 communicating with the storage space 150. That is, the inlet 122 is provided on one side of the case 100 so as to communicate with the storage space 150 provided inside the case 100.

The ultra-low temperature refrigerator of the present invention may include an insulating material (not shown) in the internal space 140 provided between the outer case 110 and the inner case 130. Therefore, heat exchange between the storage space 150 and the outside of the case 100 can be prevented.

The external door 200 opens and closes the inlet 122 to prevent the cooled air from inside the storage space 150 from leaking to the outside.

The external door 200 may be rotatably connected to the case 100 and to the external door hinge 250. The external door 200 may include an external door case 210 forming the exterior, and an insulation material (not shown) provided inside the external door case 210.

When the external door 200 is closed, it may include an external door insertion part 240 that extends toward the inlet 122 and protrudes. The external door insertion portion 240 may be provided with a smaller cross-sectional area than the inlet 122. When the external door 200 is closed, the external door insertion part 240 is inserted into the inlet 122, so the external door 200 is fixed without shaking from side to side on the upper side of the case 100.

The external door 200 may include an external door handle 220 protruding from the front end.

The cryogenic refrigerator of the present invention may include a gasket 230 for sealing between the external door 200 and the inlet 122.

The gasket 230 can be fixed to the lower surface of the external door 200, and seals the space between the inlet 122 and the external door 200 by the load of the external door 200 when the external door 200 is closed. This prevents cold air inside the storage space 150 from leaking to the outside.

The gasket 230 may be provided around the outer door insertion portion 240.

The gasket 230 may seal between the upper surface of the case and the lower surface of the external door 200, and/or the gasket 230 may seal the inner peripheral surface of the case 100 and the outer peripheral surface of the external door insertion portion 240. You may.

When the external door 200 is opened and closed to take out stored items from an operating ultra-low temperature refrigerator, the outside air flowing into the storage space 150 is instantaneously condensed, generating a large negative pressure inside the storage space 150.

This is because when the external door 200 is closed, the internal air of the storage space 150 sealed by the gasket 230 cannot flow with external air.

Accordingly, even if an attempt is made to open the external door 200 again, the external door 200 does not open, and there is a problem in that a time period during which the external door 200 is not opened occurs.

In order to solve this problem, the cryogenic refrigerator of the present invention may include an internal door 300 provided inside the storage space 150 to partition the storage space 150.

The storage space 150 may be divided into a first space 152 formed by the external door 200 and the internal door 300, and a second space 154 in which storage items are stored.

The inner door 300 may be provided horizontally at the input port 122 inside the storage space 150.

The first space 152 may be provided on the upper side of the inner door 300, or may be provided in the direction from the inner door 300 toward the inlet 122. The second space 154 may be provided on the lower side of the inner door 300, or may be provided in the opposite direction of the inlet 122 in the inner door 300.

The second space 154 is a space where items are actually stored, and is provided with a larger volume than the first space 152. The second space 154 is formed by the inner door 300 and the inner case 130, and makes up most of the storage space 150.

The first space 152 serves to prevent large negative pressure from being generated inside the external door 200 when the external door 200 is opened and closed and then opened again.

This does not mean that the first space 152 and the second space 154 are completely sealed to each other so that no air flows, but rather that the storage space 150 is spatially partitioned. That is, the first space 152 and the second space 154 are provided to allow air flow, and a large amount of air flow is prevented from occurring between the first space 152 and the second space 154. The first space 152 and the second space 154 are divided.

With reference to FIGS. 3 and 4, a first embodiment of the inner door 300 will be described.

The inner door 300 is provided to be slidable inside the storage space and includes a first inner door 310 that opens and closes a portion of the inner opening 132, and an inner opening that is not opened or closed by the first inner door 310 ( 132) may include a second inner door 330 that closes the remaining portion.

The first inner door 310 is provided on the upper side of the second inner door 330 and can be slidably in contact with the upper surface of the second inner door 330. Therefore, when the first inner door 310 is slid and moved in one direction, a portion of the inner opening 132 that was closed by the first inner door 310 is opened, and when the first inner door 310 is slid and moved in the opposite direction, the inner opening 132 is opened. Close part of the Since this is the same for the second inner door 330, detailed description will be omitted.

The first inner door 310 and the second inner door 330 may be slidable in the longitudinal direction of the inlet 122.

The sum of the cross-sectional areas of the first inner door 310 and the second inner door 330 may be larger than the sum of the cross-sectional areas of the inlet 122.

The longitudinal lengths of the first internal door 310 and the second internal door 330 may be different from each other, and the longitudinal length of the first internal door may be longer than the longitudinal length of the second internal door. It can be.

The unidirectional (width direction) lengths of the first inner door 310 and the second inner door 330 may be different from each other, and the width length W2 of the second inner door is equal to that of the first inner door 310. It can be provided longer than the width and length (W1).

Here, the long direction and the single direction refer to the long edge and short edge, respectively, on the outer peripheral surface of the first inner door 310 or the second inner door 330.

Meanwhile, the upper surface of the first inner door 310 may be provided with concave first inner door handles 312 on both sides in one direction. Two first inner door handles 312 may be provided at the longitudinal center of the upper surface of the first inner door 310. Additionally, the upper surface of the second inner door 330 may be provided with concave second inner door handles 332 on both sides in one direction. Two second inner door handles 332 may be provided at the longitudinal center of the upper surface of the second inner door 330.

In this case, when the ends of the second inner door 330 and the first inner door 310 are aligned, the width length W2 of the second inner door 330 and the width length of the first inner door 310 ( The difference in W1) may be the exposed length of only one of the two second inner door handles provided on the upper surface of the second inner door 330. That is, when the first inner door 310 is slid to the upper side of the second inner door 330, one of the two second inner door handles provided on the second inner door 330 is exposed upward at some time. The user can hold the second inner door handle 332 and move the second inner door 330 to both sides.

Meanwhile, the first inner door 310 may be guided by the upper surface of the first guider 124 extending from the bottom of the first predetermined depth H1 at the inlet 122 to the inside of the storage space 150, The second inner door 330 can be guided by the upper surface of the second guider 126 extending from the end of the first guider 124 to the inside of the storage space 150 at the bottom of the second predetermined depth H2. there is.

In other words, the first guider 124 is provided to extend from the inner peripheral surface of the storage space 150 to the inside of the storage space 150. In addition, the second guider 126 is provided to extend from the inner peripheral surface of the storage space 150 to the inside of the storage space 150, and may be provided to extend further than the first guider 124.

In this case, the thickness D1 of the first inner door 310 may be smaller than the first predetermined depth H1. However, it is preferable that the length of the first predetermined depth H1 is within twice the length of the thickness D1 of the first inner door 310. This is because the sound pressure due to condensation of external air in the first space 152 can be minimized only by minimizing the volume of the first space 152.

Additionally, the thickness D2 of the second inner door 330 may be less than or equal to the second predetermined depth H2. Therefore, the gap between the first inner door 310 and the second inner door 330 is minimized to prevent cold air inside the storage space from leaking between the first inner door 310 and the second inner door 330. do.

Figure 5 is a bottom view of the first inner door or the second inner door provided in the ultra-low temperature refrigerator of the present invention. Figure 6 is a diagram showing an exploded perspective view of the first inner door or the second inner door provided in the ultra-low temperature refrigerator of the present invention. FIG. 7A is a cross-sectional view taken along line C-C′ of FIG. 5. FIG. 7B is a cross-sectional view taken along line D-D′ of FIG. 5.

Referring to FIGS. 5 to 7, the first inner door or the second inner door will be described. Since the structures other than the longitudinal length and unidirectional length of the first inner door or the second inner door are the same, hereinafter, the terminology of the inner door will be used instead of the terminology of the first inner door and the second inner door. The description can be equally applied to the first inner door and the second inner door.

The inner door 300 may include a transparent member 380 that allows the storage space to be viewed from the outside, and an inner door frame 350 provided around the transparent member 380.

Since the transparent member 380 is provided inside the storage space 150, which is a very low temperature environment, it can be made of tempered glass that can withstand a very low temperature environment.

The inner door frame 350 may be made of plastic and may have a rectangular shape.

Additionally, the inner door frame 350 may include a penetrating portion 360 formed by the inner peripheral surface of the inner door frame 350, and the penetrating portion 360 may be provided in a rectangular shape.

The longitudinal length l2 of the penetrating portion 360 may be longer than the longitudinal length l1 of the transparent member 380. This is because the transparent member, which is tempered glass, does not shrink much even in an ultra-low temperature environment, but the inner door frame 350 is made of a plastic material, so it shrinks a lot.

The inner peripheral surface of the inner door frame 350 forming the penetrating portion 360 includes a first edge 362, a second edge 364 opposing the first edge 362, a first edge 362, and a second edge 364. It can be formed with edges 366 on both sides connecting the edges 364.

The inner door frame 350 extends from the inner peripheral surface and may include a front support portion 372 that supports the front side of the transparent member and a rear support portion 374 that supports the rear side of the transparent member.

The front support portion 372 may be provided to support the entire periphery of the front edge of the transparent member 380.

The rear support portion 374 includes a first rear support portion 374a extending from the first edge 362, and a second rear support portion extending from the second edge 364, but extending shorter than the first rear support portion 374a ( It may include 374b) and a third rear support portion 374c extending from both edges 366. The third rear support portion 374c includes a cut portion 368 cut to a predetermined length on the second rear support portion 374b, and the transparent member 380 is connected to the front support portion 372 and the front support portion 372 through the cut portion 368. It is inserted between the rear supports 374 so that it can be fixed.

Meanwhile, the inner door frame 350 may include at least one of a plurality of first reinforcing ribs 392 provided in the longitudinal direction of the inner door frame 350 and a second reinforcing rib 394 provided in a unidirectional direction. there is.

The first reinforcing rib 392 and the second reinforcing rib 394 may be provided on the lower surface of the inner door frame 350.

The inner door frame 350 includes a first member 352 and a second member 354 that are unidirectional, and a third member that connects the first member 352 and the second member 354 in a longitudinal direction ( 356) and a fourth member 358.

The first reinforcing ribs 392 are provided in parallel in the longitudinal direction of the third member 356 or/and the fourth member 358, and are provided in plurality of the first member 352 or/and the second member 354. A plurality of them may be provided vertically in the longitudinal direction.

In this case, the spacing S1 of the first reinforcing ribs 392 provided in the third member or/and the fourth member is the spacing (S1) of the first reinforcing ribs 392 provided in the first member or/and the second member ( It can be provided narrower than S2). Because the third and fourth members are provided longer than the first and second members, the shrinkage length of the third and fourth members is longer than that of the first and second members in a cryogenic environment. Therefore, in order to prevent shrinkage in ultra-low temperature conditions, the spacing of the first reinforcing ribs 392 is narrow.

Meanwhile, a plurality of second reinforcing ribs 394 may be provided perpendicular to the longitudinal direction of the third member 356 and/or the fourth member 358. Accordingly, shrinkage of the third member 356 and the fourth member 358 can be minimized.

Figure 8 is a diagram showing a second embodiment of the inner door provided in the ultra-low temperature refrigerator of the present invention. Figure 9 is a diagram showing a third embodiment of the inner door provided in the ultra-low temperature refrigerator of the present invention. Figure 10 is a diagram showing a fourth embodiment of the inner door provided in the ultra-low temperature refrigerator of the present invention.

Hereinafter, various embodiments of the inner door will be described with reference to FIGS. 8 to 10. The description of the first embodiment of the inner door, excluding the inner door and the structure changed to install the inner door, can be applied to other embodiments of the inner door, and only the differences will be described below.

Referring to FIG. 8, the inner door 400 of the second embodiment provided in the present invention can be rotatable inside the storage space 150.

The inner door 400 of the second embodiment may be rotatably connected to the inner door hinge 410 on one side of the storage space 150. The inner door hinge 410 may be provided on the inner peripheral surface of the case 100 equipped with the outer door hinge 250.

The inner door 400 of the second embodiment is supported by the upper surface of the third guider 430 extending from the inner peripheral surface of the storage space 150, and the third guider 430 is at a third predetermined depth ( It can be provided at the bottom of H3).

In this case, the third predetermined depth H3 may be longer than the thickness D3 of the inner door 400 of the second embodiment. However, it is preferable that the third predetermined depth H3 is smaller than twice the thickness D3 of the inner door 400 of the second embodiment.

The third guider 430 may be provided around the entire or partial inner surface of the storage space 150.

In this case as well, the storage space 150 is divided into a first space 152 above the inner door 400 of the second embodiment and a second space 154 below, and is divided into a second space 154 below the inner door 400 of the second embodiment. The volume of the second space 154 is provided to be large.

The inner door hinge 410 may be located on the upper surface of the third guider 430. When the inner door 400 of the second embodiment is closed, the upper side of the storage space 150 is closed to form a second space 154, and when the outer door 200 is closed, a first space 152 is formed. do.

Meanwhile, the cryogenic refrigerator of the present invention may include an opening delay unit 420 that interlocks the outer door 200 and the inner door so that the inner door can be automatically opened after the outer door 200 is opened.

The inner door 400 of the second embodiment can be automatically opened and closed a predetermined time after the outer door 200 is opened by the opening delay unit 420. Therefore, when the outer door is reopened after opening and closing, the inner door remains closed until the outer door is reopened, so a large negative pressure is applied only in the second space 154, and a small negative pressure is applied in the first space 152. The external door 200 can be opened with a small force due to negative pressure, and after the external door is opened, air flows through the gap between the internal door and the storage space 150, thereby eliminating the large negative pressure in the second space. The inner door can be opened with little force.

As shown in FIG. 8, the opening delay part 420 connects the inner door and the outer door 200, and may be provided as a line longer than the gap between the inner door and the outer door 200. Therefore, when the outer door 200 is closed, no tension is generated, but after the outer door 200 is opened, tension is generated so that the inner door can be opened. Through this, a time interval can be provided between the opening and closing of the external door 200 and the internal door, and the internal door can be automatically opened and closed a predetermined time after the external door 200 is opened.

Referring to FIG. 9, the inner door 500 of the third embodiment provided in the present invention can be slidable inside the storage space 150.

The inner door 500 of the third embodiment is supported by the upper surface of the fourth guider 510 extending from the inner peripheral surface of the storage space 150 to the inside of the storage space 150, and the fourth guider 510 is connected to the inlet 122. ) may be provided at the bottom of the fourth predetermined depth (H4).

In this case, the fourth predetermined depth H4 may be longer than the thickness D4 of the inner door 500 of the third embodiment. However, it is preferable that the fourth predetermined depth H4 is smaller than twice the thickness D4 of the inner door 500 of the third embodiment.

The fourth guider 510 may be provided around the entire or partial inner circumferential surface of the storage space 150.

The inner door 500 of the third embodiment may be made of a shutter with a plurality of members each rotatably provided, and the inner door 500 of the third embodiment may have a shutter insertion hole provided on the inner peripheral surface of the storage space 150 ( 520) to enter and exit. The shutter insertion hole 520 may be provided above the fourth guider 510.

Therefore, when the upper surface of the fourth guider 510 is slid and moved backward so that the inner door 500 of the third embodiment is inserted into the shutter insertion hole 520, the upper side of the storage space 150 is opened, and the third The upper side of the storage space 150 can be closed by sliding the upper surface of the fourth guider 510 and moving forward so that the inner door 500 of the embodiment is pulled out from the shutter insertion hole 520.

That is, the inner door 500 of the third embodiment made of a shutter can partition the storage space 150 while moving the upper surface of the fourth guider 510.

In this case as well, the storage space 150 is divided into a first space 152 on the upper side of the inner door and a second space 154 on the lower side, and the volume of the second space 154 is larger than that of the first space 152. It is provided to be large.

Meanwhile, a shutter stopper 530 may be provided at the end of the inner door 500 of the third embodiment to restrict movement when the inner door enters the shutter insertion hole 520. Therefore, it is possible to prevent the inner door from being completely inserted into the shutter insertion hole 520. Additionally, a shutter handle 540 that is concave so that the user's hand can be inserted may be provided on the front upper surface of the inner door.

Referring to FIG. 10, the inner door 600 of the fourth embodiment provided in the present invention has a third inner door 620 rotatably connected to the inside of the storage space 150, and a third inner door 620. It may include a fourth inner door 630 that is rotatably connected and has a free end.

The third inner door 620 is connected to the storage space 150 by a third hinge 622, and the fourth inner door 630 is connected to the third inner door 620 by a fourth hinge 632. do.

The inner door 600 of the fourth embodiment is supported by the upper surface of the fifth guider 610 extending from the inner peripheral surface of the storage space 150 to the inside of the storage space 150, and the fifth guider 610 is an inlet ( 122), it may be provided at the bottom of the fifth predetermined depth H5.

In this case, the fifth predetermined depth H5 may be longer than the thickness D5 of the inner door 600 of the fourth embodiment. However, it is preferable that the fifth predetermined depth H3 is smaller than twice the thickness D5 of the inner door 600 of the fourth embodiment.

The fifth guider 610 may be provided around the entire or partial inner circumferential surface of the storage space 150.

The third hinge 622 of the third inner door may be located on the upper surface of the fifth guider 610.

When the inner door 600 of the fourth embodiment is closed, both the third inner door 620 and the fourth inner door 630 are supported by the fifth guider 610, and the upper side of the storage space 150 is closed. do.

Conversely, when the inner door 600 of the fourth embodiment is open, the third inner door 620 rotates upward, the fourth inner door 630 rotates in the opposite direction to the third inner door 620, and the third inner door 620 rotates upward. The free end of the door 620 is supported by the fifth guider 610, and the upper side of the storage space 150 is opened.

In this case as well, the storage space 150 is divided into a first space 152 on the upper side of the inner door and a second space 154 on the lower side, and the volume of the second space 154 is larger than that of the first space 152. It is provided to be large.

According to the various embodiments of the inner door described above, in the present invention, when the outer door is opened, closed and reopened, most of the large negative pressure generated in the second space 154 due to condensation of the outside air acts on the inner door. , a small negative pressure generated in the first space 152 due to condensation of the outside air acts on the external door, so that the external door can be reopened immediately.

FIG. 11 is a cross-sectional view taken along line E-E′ in FIG. 1. Figure 12 is a diagram showing a first embodiment of the cooling unit 700 that can be provided in the ultra-low temperature refrigerator of the present invention. With reference to FIGS. 11 and 12, the present invention will describe a first embodiment of a cooling unit included in an ultra-low temperature refrigerator.

The ultra-low temperature refrigerator of the present invention may include a cooling unit 700 between the outer case 110 and the inner case 130 that implements a refrigeration cycle capable of cooling the storage compartment.

The refrigeration cycle operates to repeat compression, condensation, expansion, and evaporation of the refrigerant.

11 and 12, the cooling unit 700 includes a compressor 710 that compresses the refrigerant, a condenser 720 that condenses the refrigerant, an expansion device 730 that expands the refrigerant, and an evaporator 740 that evaporates the refrigerant. may include.

The compressor 710, condenser 720, expansion device 730, and evaporator 740 are connected by a refrigerant pipe 750. The condenser 720 is connected to the outlet side of the compressor 710, the expansion device 730 is connected to the outlet side of the condenser 720, and the evaporator 740 is connected to the outlet side of the expansion device 730, The compressor 710 is connected to the outlet side of the evaporator 740 and has a circulation structure.

The compressor 710 compresses the refrigerant to produce high temperature and high pressure. The compressor 710 may be installed in the machine room 718 provided in the internal space 140.

The machine room 718 is provided between the inner case 130 and the outer case 110, and may be provided on the right and lower sides when viewed from the front of the ultra-low temperature refrigerator 1, and may be provided long in the front-back direction. (See Figures 2 and 11)

The machine room 718 may include a cooling fan 716 for cooling the compressor 710.

The condenser 720 condenses the mixed refrigerant discharged from the compressor 710. The refrigerant condensed inside the condenser 720 releases heat, and the released heat is released to the outside of the condenser 720 to exchange heat with external air. The condenser 720 is provided on the outer rear surface of the case 100 and can exchange heat with the external air of the case 100.

Meanwhile, the refrigerant pipe 750 connecting the condenser 720 and the evaporator 740 may further include a dryer 725. The dryer 725 filters out moisture or foreign substances from the refrigerant condensed in the condenser 720.

The expansion device 730 depressurizes the refrigerant condensed in the condenser 720. The expansion device 730 may include a capillary tube or an expansion valve.

The evaporator 740 evaporates the refrigerant depressurized in the expansion device 730. The evaporator 740 absorbs heat by exchanging heat from the outside of the evaporator 740 to evaporate the refrigerant, so the surrounding area of the evaporator 740 is cooled.

The evaporator 740 may be provided around the outer peripheral surface of the inner case 130. In this case, the evaporator 740 is provided in the form of a tube and directly contacts the outer peripheral surface of the inner case 130 to absorb heat from the inner case 130 and lower the temperature of the inner case 130.

To implement an ultra-low temperature refrigerator, a refrigerant with a low boiling point can be used. However, if a refrigerant with a low boiling point is used alone, the discharge pressure of the compressor may increase, which may reduce the reliability of the compressor. To prevent this, a mixed refrigerant that mixes two or more refrigerants with different boiling points can be used.

The mixed refrigerant is an azeotropic refrigerant mixture whose temperature does not change in a quasi-equilibrium state when liquefaction or vaporization occurs between the liquid phase and the gas phase under a certain pressure, and a non-azeotropic mixed refrigerant whose temperature changes during the liquefaction or vaporization process. may include a refrigerant mixture).

A refrigerator that implements a cryogenic refrigerator using a mixed refrigerant is described in detail in prior document US 7,299,653 B2 (registration date: November 27, 2007), but the mixing ratio is not optimized, so the optimized cryogenic state and the appropriate discharge pressure of the compressor are not possible. There was a problem that made it difficult to satisfy everyone.

The compressor 710 may be a household compressor included in a general household refrigerator. A typical household compressor has a lower discharge pressure than an industrial compressor, but can achieve low noise.

The compressor 710 may be equipped to have a maximum discharge pressure of 25 bar or less, a maximum discharge temperature of 120° C. or less, and a minimum suction force of 1 bar or less. Home compressors have the advantage of producing less noise when operating.

The refrigerant sucked into the compressor 710 may include a mixed refrigerant. The mixed refrigerant may include a high-temperature refrigerant having a first boiling point and a low-temperature refrigerant having a second boiling point lower than the first boiling point.

In this case, an ultra-low temperature refrigerator can be implemented using a low-temperature refrigerant, but the low-temperature refrigerant has a relatively high discharge pressure when compressed, causing an overload in the compressor. In contrast, high-temperature refrigerants have a relatively low discharge pressure when compressed, thus reducing the load on the compressor. Therefore, the appropriate ratio of low-temperature refrigerant and high-temperature refrigerant is important to achieve ultra-low temperature and prevent compressor overload. Below we will look at the appropriate ratio of low-temperature refrigerant and high-temperature refrigerant.

In general, high-temperature refrigerants may include isopentane, 1,2-butadiene, butane (N-Butane), 1-Butene, or isobutane. You can. However, isopentane and 1,2-butadiene are undesirable for implementing ultra-low temperature refrigerators due to their high evaporation temperature, and butane (N-Butane) and 1-butene are not suitable for use in ultra-low temperature refrigerators. Since the evaporation temperature is too low, there is a problem that the discharge pressure of the compressor is slightly increased, so in the present invention, it is preferable to use butane (N-Butane) whose evaporation temperature is close to 0 ° C at 1 bar.

Meanwhile, low-temperature refrigerants may generally include ethane or ethylene. However, ethane has a somewhat high evaporation temperature, which poses a problem in implementing a cryogenic refrigerator. Therefore, in the present invention, it is preferable to use ethylene, which has an evaporation temperature of -100°C or lower at 1 bar.

On the other hand, when using N-Butane as the high-temperature refrigerant and ethylene as the low-temperature refrigerant, the ratio of the high-temperature refrigerant to the low-temperature refrigerant is determined within the range of 80-85% by weight of the high-temperature refrigerant. , the low temperature refrigerant can be determined within the range of 15-20% by weight.

In this case, as the weight of butane (N-Butane), a high-temperature refrigerant, relatively increases, the maximum discharge pressure, minimum suction pressure, and maximum discharge temperature of the compressor decrease, and the minimum temperature that can be achieved in the storage room increases.

As seen above, in order to meet the operating pressure and temperature range of the household compressor 710, the highest discharge pressure must be 25 bar or less, the highest discharge temperature must be 120°C or less, and the lowest suction pressure must be 1 bar or more. The ratio of N-Butane and Ethylene that satisfies these conditions forms a weight percent ratio of 80:20 to 85:15. And, within this range of weight percent, the temperature of the storage room at which the ultra-low temperature refrigerator can achieve the required performance, for example, a value of -60°C or lower, can be formed.

Meanwhile, the refrigerant pipe 750 includes a condensation pipe 752 extending from the outlet of the condenser 720 to the expansion device 730, and a suction pipe 754 extending from the outlet of the evaporator 740 to the compressor 710. may include.

In order to improve operating efficiency, the ultra-low temperature refrigerator of the present invention may include a first heat exchanger 760 in which heat is exchanged between the refrigerant flowing through the condensation pipe 752 and the refrigerant flowing through the suction pipe 754. For example, portions of the condensation pipe 752 and the suction pipe 754 may be joined by soldering to directly contact each other and exchange heat.

Accordingly, the low-temperature refrigerant flowing through the suction pipe 754 can cool the high-temperature refrigerant flowing through the condensation pipe 752, thereby lowering the condensation pressure and the discharge pressure of the compressor 710. . Additionally, the refrigerant flowing through the suction pipe 754 can reduce the proportion of liquid refrigerant (specific effective cooling power) among the refrigerants through heat absorption.

In addition, in order to improve operating efficiency, the cryogenic refrigerator of the present invention may include a second heat exchanger 762 in which heat is exchanged between the refrigerant flowing through the expansion device 730 and the refrigerant flowing through the suction pipe 754. For example, a portion of the expansion device 730 and the suction pipe 754 may be joined by soldering to directly contact each other and exchange heat.

Accordingly, the low-temperature refrigerant flowing through the suction pipe 754 can cool the high-temperature refrigerant flowing through the expansion device 730, thereby lowering the ratio of the refrigerant decompressed in the expansion device 730 to a vapor phase refrigerant. . In other words, the increase in dryness of the refrigerant can be reduced. For reference, as the proportion of gaseous refrigerant flowing into the evaporator 740 increases, the proportion of liquid refrigerant that can evaporate in the evaporator 740 decreases, making it difficult to implement a cryogenic refrigerator.

Based on the flow direction of the refrigerant flowing through the suction pipe 754, the first heat exchanger 760 may be installed on the outlet side of the second heat exchanger 762. However, the first heat exchanger 760 and the second heat exchanger 762 are provided spaced apart from each other so that heat exchange does not occur between them.

Figure 13 is a diagram showing a second embodiment of the cooling unit 700 that can be provided in the ultra-low temperature refrigerator of the present invention. Figure 14 is a diagram showing a third embodiment of the cooling unit 700 that can be provided in the ultra-low temperature refrigerator of the present invention. Figure 15 is a diagram showing a fourth embodiment of the cooling unit 700 that can be provided in the ultra-low temperature refrigerator of the present invention. Figure 16 is a diagram showing a fifth embodiment of the cooling unit 700 that can be provided in the ultra-low temperature refrigerator of the present invention. Hereinafter, various embodiments of the cooling unit 700 will be described with reference to FIGS. 13 to 16. However, since these embodiments differ only in some configurations compared to the first embodiment of the cooling unit 700, the differences will be explained, and reference numerals will be used for the same parts.

Referring to FIG. 13, the second embodiment of the cooling unit 700 is a compressor 710, a condenser 720, a dryer 725, an expansion device 730, and a first connected to the outlet side of the expansion device 730. An evaporator 742, a second evaporator 744 connected to the outlet side of the first evaporator 742, a condensation pipe 752 connected from the condenser 720 to the expansion device 730, and a second evaporator 744. It may include a suction pipe 754 connected to the compressor 710.

A first heat exchanger 760 that exchanges heat between the refrigerant flowing in the condensation pipe 752 and the refrigerant flowing in the suction pipe 754, and heat exchanges between the refrigerant flowing in the expansion device 730 and the refrigerant flowing in the suction pipe 754. It may include a second heat exchanger 762, and based on the flow direction of the refrigerant flowing through the suction pipe 754, the first heat exchanger 760 is installed on the outlet side of the second heat exchanger 762. It can be.

Meanwhile, it may include a first internal case forming a first storage compartment and a second internal case forming a second storage compartment corresponding to the first evaporator 742 and the second evaporator 744. The first evaporator 742 is provided around the first inner case and can create an environment in the first storage compartment at a very low temperature (eg, -60°C or lower). In addition, the second evaporator 744 is provided around the second inner case to create an environment in the second storage compartment at a low temperature (for example, around -20°C).

Referring to FIG. 14, the third embodiment of the cooling unit 700 includes a compressor 710, a condenser 720, a dryer 725, two expansion devices 730, and a device connected at the outlet of the expansion device 730. It may include two evaporators 740, a condensation pipe 752 connected from the condenser 720 to the expansion device 730, and a suction pipe 754 connected from the evaporator 740 to the compressor 710. .

The two expansion devices 730 are connected in parallel to the first expansion device 732 and the first expansion device 732 through which at least a portion of the refrigerant flowing in the condensation pipe 752 can flow, and the condensation pipe (752) It may include a second expansion device 734 through which another part of the refrigerant flowing 752) can flow.

A valve device 726 is installed in the condensation pipe 752 to control the amount of refrigerant so that the refrigerant flowing through the condensation pipe 752 can flow into at least one of the first expansion device 732 and the second expansion device 734. It can be. The valve device 726 may be composed of a three-way valve, and a condensation pipe 752 is connected to the inlet end of the three-way valve, and a first expansion device 732 and a second expansion device are connected to the two outlet ends of the three-way valve. Devices 734 may each be connected.

Meanwhile, the two evaporators 740 may include a first evaporator 742 connected to the outlet side of the first expansion device 732 and a second evaporator 744 connected to the outlet side of the second expansion device. .

And, a first evaporation pipe 742a extending from the first outlet of the valve device 726 to the first evaporator 742 and a first evaporation pipe 742a extending from the second outlet of the valve device 726 to the second evaporator 744. A second evaporation pipe 744a may be provided.

The first evaporation pipe 742a and the second evaporation pipe 744a can be joined at the joining portion 743. The joining portion 743 may be a point of the first evaporation pipe 742a or the second evaporation pipe 744a. With this configuration, the first evaporator 742 and the second evaporator 744 can be connected in parallel.

A check valve may be installed in the first evaporation pipe 742a to guide the one-way flow of the refrigerant in the first evaporation pipe 742a. The flow of refrigerant from the joining portion 743 toward the first evaporator 742 may be restricted by the check valve. Ultimately, the refrigerant that has passed through the second evaporator 744 can be prevented from flowing into the first evaporator 742 through the joining portion 743.

By controlling the valve device 726, at least one of the first and second evaporators 740 may be operated. When the first outlet of the two outlets of the valve device 726 is open and the second outlet is closed, only the refrigerant flow from the valve device 726 to the first evaporator 742 can occur.

On the other hand, when the second outlet of the two outlets of the valve device 726 is open and the first outlet is closed, only the refrigerant flow from the valve device 726 to the second evaporator 744 can occur. When both outlets of the valve device 726 are opened, the refrigerant flowing into the valve device 726 may branch and flow to the first and second evaporators through the first and second outlets.

A plurality of storage chambers corresponding to a plurality of evaporators 740 may be included. The plurality of storage rooms may include two cryogenic storage rooms of -60°C or lower. As another example, the plurality of storage compartments may include a cryogenic storage compartment of -60°C or lower and a freezer compartment of approximately -20°C.

The refrigerant that has passed through the first evaporator 742 or the second evaporator 744 may pass through the second heat exchanger 762. The second heat exchanger 762 may include at least a portion of the first expansion device 732, the second expansion device 734, and the suction pipe 754.

Based on the refrigerant flow direction of the suction pipe 754, the first heat exchanger 760 may be installed on the outlet side of the second heat exchanger 762. The first heat exchanger 760 may include at least a portion of the condensation pipe 752 and at least a portion of the suction pipe 754.

Referring to FIG. 15, the fourth embodiment of the cooling unit 700 includes a compressor 710, a condenser 720, a dryer 725, an expansion device 730, and an expansion device 730 extending from the condenser 720. A condensation pipe 752 may be included.

A first heat exchanger 760 that performs heat exchange between a portion of the condensation pipe 752 and a portion of the suction pipe 754, and a second heat exchanger that performs heat exchange between the expansion device 730 and a portion of the suction pipe 754. (762) is included. The description of the above configurations refers to the description of the first embodiment of the cooling unit 700.

A plurality of evaporators 740 may be provided to evaporate the refrigerant decompressed in the expansion device 730, and the plurality of evaporators 742, 744, and 746 may be installed on the outlet side of the expansion device 730. It may include an evaporator 742, a second evaporator 744 installed on the outlet side of the first evaporator 742, and a third evaporator 746 installed on the outlet side of the second evaporator 744. That is, the first, second, and third evaporators may be connected in series.

A plurality of storage compartments corresponding to the plurality of evaporators 742, 744, and 746 may be provided, and the plurality of storage compartments may include a cryogenic storage compartment of -60 or less, a freezer compartment of about -20, and a refrigerator compartment of 0 to 5. The cold air generated in the first evaporator 742 may be supplied to the cryogenic storage compartment, the cold air generated in the second evaporator 744 may be supplied to the freezer, and the cold air generated in the third evaporator 746 may be supplied to the refrigerator compartment. can be supplied.

Based on the refrigerant flow direction of the suction pipe 754, the first heat exchanger 760 may be installed on the outlet side of the second heat exchanger 762. The first heat exchanger 760 may include at least a portion of the condensation pipe 752 and at least a portion of the suction pipe 754.

Referring to FIG. 16, the fifth embodiment of the cooling unit 700 may include two independent refrigeration cycles, and the two independent refrigeration cycles may have the same configuration. The two refrigeration cycles may include a first refrigeration cycle and a second refrigeration cycle.

The first refrigeration cycle includes a first compressor 712, a first condenser 722, a first dryer 725a, a first expansion device 732, a first condensation pipe 752a, a first evaporator 742, and a first refrigeration cycle. 1 It may include a suction pipe (754a), a second heat exchanger (762), and a first heat exchanger (760).

The second refrigeration cycle includes a second compressor (714), a second condenser (724), a second dryer (725b), a second expansion device (734), a second condensation pipe (752b), a second evaporator (744), and a second refrigeration cycle. 2 It may include a suction pipe (754b), a fourth heat exchanger (766), and a third heat exchanger (764).

Two independent refrigeration cycles are operated to cool a plurality of storage chambers provided in the ultra-low temperature refrigerator. The plurality of storage chambers may be cooled in one of the first and second refrigeration cycles, respectively, and may include two cryogenic storage chambers of -60 degrees Celsius or lower.

The present invention can be modified and implemented in various forms, and its scope is not limited to the above-described embodiments. Therefore, if the modified embodiment includes elements of the claims of the present invention, it should be considered to fall within the scope of the present invention.

100: Case 110: External case
112: external opening 120: cover case
122: Inlet 124: First guider
126: Second guider 130: Internal case
132: internal opening 140: internal space
150: storage space 152: first space
154: Second space 200: External door
220: External door handle 230: Gasket
240: External door insertion part 250: External door hinge
300: inner door 310: first inner door
312: First inner door handle 330: Second inner door
332: Second inner door handle 350: Inner door frame
352: first member 354: second member
356: Third member 358: Fourth member
360: Penetrating part 362: First edge
364: Second corner 366: Both corners
368: cutout 372: front support
374a: first rear support 374b: second rear support
374c: third rear support 374: rear support
380: Transparent member 392: First reinforcing rib
394: Second reinforcing rib 410: Inner door hinge
420: Opening delay unit 430: Third guider
510: Fourth guider 520: Shutter insertion hole
530: Shutter stopper 540: Shutter handle
610: 5th guider 620: 3rd inner door
622: Third hinge 630: Fourth inner door
632: Fourth hinge 700: Cooling unit
710: Compressor 712: First compressor
714: second compressor 716: cooling fan
718: Machine room 720: Condenser
722: first condenser 724: second condenser
725: Dryer 725a: First dryer
725b: Second dryer 726: Valve device
730: Expansion device 732: First expansion device
734: second expansion device 740: evaporator
742: First evaporator 742a: First evaporation pipe
743: joint part 744: second evaporator
744a: Second evaporation pipe 746: Third evaporator
750: Refrigerant pipe 752: Condensation pipe
752a: First condensation pipe 752b: Second condensation pipe
754a: First suction pipe 754b: Second suction pipe
754: Suction pipe 760: First heat exchanger
762: Second heat exchanger 764: Third heat exchanger
766: Fourth heat exchanger

Claims (16)

A case including a storage space cooled to ultra-low temperature using a refrigeration cycle containing a mixed refrigerant;
an inlet provided in the case to communicate with the storage space;
an external door rotatably provided on the case to open and close the inlet;
A gasket provided on the outer door to seal between the outer door and the inlet;
It includes an internal door provided inside the storage space to partition the storage space,
The mixed refrigerant consists of a high-temperature refrigerant having a first boiling point and a low-temperature refrigerant having a second boiling point lower than the first boiling point,
The mixed refrigerant is
The high-temperature refrigerant is one of isopentane, 1,2-butadiene, butane (N-Butane), 1-Butene, and isobutane, and The low-temperature refrigerant is a combination of ethane and ethylene.
The storage space includes a first space formed by the inner door and the outer door, and a second space in which storage items are stored and a volume larger than the first space,
A cryogenic refrigerator, characterized in that the first space and the second space are provided with a gap to allow air flow. delete delete According to paragraph 1,
An ultra-low temperature refrigerator is characterized in that the storage space cooled to ultra-low temperature is cooled to a lower temperature than the freezer compartment of a general household refrigerator. According to paragraph 1,
The case includes a first guider extending from the inner peripheral surface of the storage space to the inside of the storage space, and a second guider extending further than the first guider,
The inner door includes a first inner door sliding on the first guider and a second inner door sliding on the second guider. According to clause 5,
A cryogenic refrigerator, characterized in that the sum of the cross-sectional areas of the first inner door and the second inner door is larger than the cross-sectional area of the inlet. According to clause 5,
A cryogenic refrigerator, characterized in that the width of the second inner door is longer than that of the first inner door. According to clause 5,
A cryogenic refrigerator comprising an inner door handle recessed in an upper surface of the first inner door or the second inner door. According to paragraph 1,
The inner door includes a transparent member through which the storage space can be viewed, and an inner door frame provided around the transparent member,
The inner door frame is a cryogenic refrigerator, characterized in that it includes a plurality of first reinforcing ribs provided in a longitudinal direction. According to paragraph 1,
an inner door hinge rotatably connecting the inner door;
A cryogenic refrigerator comprising an opening delay unit that interlocks the outer door and the inner door to open the inner door a predetermined time after the outer door is opened. According to paragraph 1,
The case includes a fourth guider extending from the inner peripheral surface of the storage space, and a shutter insertion hole communicating with the inside of the case above the fourth guider,
The inner door slides on the fourth guider and consists of a shutter inserted into the shutter insertion hole to partition the storage space. According to paragraph 1,
The case includes a fifth guider extending from the inner peripheral surface of the storage space,
The inner door is supported on the upper surface of the fifth guider, is rotatably provided with a third inner door rotatably connected to the inside of the storage space, and the third inner door 620, and has a free end. A cryogenic refrigerator comprising a fourth inner door. delete delete According to paragraph 1,
The refrigeration cycle is connected by refrigerant pipes in the following order: compressor, condenser, expansion device, and evaporator,
The refrigerant pipe includes a condensation pipe extending from the outlet of the condenser to the expansion device, and a suction pipe extending from the outlet of the evaporator to the compressor,
A first heat exchanger in which heat exchange occurs between the refrigerant flowing in the condensation pipe and the refrigerant flowing in the suction pipe, and a second heat exchanger in which heat exchange occurs between the refrigerant flowing in the expansion device and the refrigerant flowing in the suction pipe. Ultra-low temperature refrigerator. According to clause 15,
A cryogenic refrigerator, characterized in that, based on the flow direction of the refrigerant flowing through the suction pipe, the first heat exchanger is provided at the outlet side of the second heat exchanger.

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