Patent ID: 12209795

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments will be described with reference to the accompanying drawings. The embodiments may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein, and a person of ordinary skill in the art, who understands the spirit, may readily implement other embodiments included within the scope of the same concept by adding, changing, deleting, and adding components; rather, it will be understood that they are also included within the scope.

The drawings shown below may be displayed differently from the actual product, or exaggerated or simple or detailed parts may be deleted, but this is intended to facilitate understanding of the technical idea. It should not be construed as limited.

In the following description, the term vacuum pressure means any pressure state lower than atmospheric pressure. In addition, the expression that a vacuum degree of A is higher than that of B means that a vacuum pressure of A is lower than that of B.

FIG.1is a perspective view of a refrigerator according to an embodiment. Referring toFIG.1, the refrigerator1includes a main body2provided with a cavity9capable of storing storage goods and a door3provided to open/close the main body2. The door3may be rotatably or slidably movably disposed to open/close the cavity9. The cavity9may provide at least one of a refrigerating compartment or a freezing compartment.

Parts constituting a freezing cycle in which cold air is supplied into the cavity9. In detail, the parts include a compressor4that compresses a refrigerant, a condenser5that condenses the compressed refrigerant, an expander6that expands the condensed refrigerant, and an evaporator7that evaporates the expanded refrigerant to take heat. As a typical structure, a fan may be installed at a position adjacent to the evaporator7, and a fluid blown from the fan may pass through the evaporator7and then be blown into the cavity9. A freezing load is controlled by adjusting a blowing amount and blowing direction by the fan, adjusting an amount of a circulated refrigerant, or adjusting a compression rate of the compressor, so that it is possible to control a refrigerating space or a freezing space. Other parts constituting the refrigeration cycle may be constituted by applying a member including a thermoelectric module.

FIG.2is a view schematically showing a vacuum adiabatic body used in the main body and the door of the refrigerator. InFIG.2, a main body-side vacuum adiabatic body is illustrated in a state in which top and side walls are removed, and a door-side vacuum adiabatic body is illustrated in a state in which a portion of a front wall is removed. In addition, sections of portions at conductive resistance sheets are provided are schematically illustrated for convenience of understanding.

Referring toFIG.2, the vacuum adiabatic body includes a first plate member (first plate)10for providing a wall of a low-temperature space, a second plate member (second plate)20for providing a wall of a high-temperature space, a vacuum space part (vacuum space)50defined as an interval part between the first and second plate members10and20. Also, the vacuum adiabatic body includes conductive resistance sheets60and63for preventing heat conduction between the first and second plate members10and20. A sealing part (sealing)61for sealing the first and second plate members10and20is provided such that the vacuum space part50is in a sealed state. When the vacuum adiabatic body is applied to a refrigerator or a warming apparatus, the first plate member10providing a wall of an inner space of the refrigerator may be referred to as an inner case, and the second plate member20providing a wall of an outer space of the refrigerator may be referred to as an outer case.

A machine room8in which parts providing a freezing cycle are accommodated is placed at a lower rear side of the main body-side vacuum adiabatic body, and an exhaust port40for forming a vacuum state by exhausting air in the vacuum space part50is provided at any one side of the vacuum adiabatic body. In addition, a pipeline64passing through the vacuum space part50may be further installed so as to install a defrosting water line and electric lines.

The first plate member10may define at least one portion of a wall for a first space provided thereto. The second plate member20may define at least one portion of a wall for a second space provided thereto. The first space and the second space may be defined as spaces having different temperatures. The wall for each space may serve as not only a wall directly contacting (facing) the space but also a wall not contacting (facing) the space. For example, the vacuum adiabatic body of the embodiment may also be applied to a product further having a separate wall contacting (facing) each space.

Factors of heat transfer, which cause loss of the adiabatic effect of the vacuum adiabatic body, are heat conduction between the first and second plate members10and20, heat radiation between the first and second plate members10and20, and gas conduction of the vacuum space part50. Hereinafter, a heat resistance unit provided to reduce adiabatic loss related to the factors of the heat transfer will be provided. The vacuum adiabatic body and the refrigerator of the embodiment do not exclude that another adiabatic means is further provided to at least one side of the vacuum adiabatic body. Therefore, an adiabatic means using foaming, for example, may be further provided to another side of the vacuum adiabatic body.

FIGS.3A-3Bare views illustrating various embodiments of an internal configuration of the vacuum space part. Referring toFIG.3A, the vacuum space part50may be provided in a third space having a pressure different from that of each of the first and second spaces, for example, a vacuum state, thereby reducing adiabatic loss. The third space may be provided at a temperature between a temperature of the first space and a temperature of the second space. As the third space is provided as a space in the vacuum state, the first and second plate members10and20receive a force contracting in a direction in which they approach each other due to a force corresponding to a pressure difference between the first and second spaces. Therefore, the vacuum space part50may be deformed in a direction in which it is reduced. In this case, the adiabatic loss may be caused due to an increase in amount of heat radiation, caused by the contraction of the vacuum space part50, and an increase in amount of heat conduction, caused by contact between the plate members10and20.

A supporting unit (support)30may be provided to reduce deformation of the vacuum space part50. The supporting unit30includes a bar31. The bar31may extend in a substantially vertical direction with respect to the plate members to support a distance between the first plate member and the second plate member. A support plate may be additionally provided on at least any one end of the bar31. The support plate may connect at least two or more bars31to each other to extend in a horizontal direction with respect to the first and second plate members10and20. The support plate may be provided in a plate shape or may be provided in a lattice shape so that an area of the support plate contacting the first or second plate member10or20decreases, thereby reducing heat transfer. The bars31and the support plate35are fixed to each other at at least one portion, to be inserted together between the first and second plate members10and20. The support plate35contacts at least one of the first and second plate members10and20, thereby preventing deformation of the first and second plate members10and20. In addition, based on an extending direction of the bars31, a total sectional area of the support plate35is provided to be greater than that of the bars31, so that heat transferred through the bars31may be diffused through the support plate35.

A material of the supporting unit30will be described hereinafter.

The supporting unit30is to have a high compressive strength so as to endure the vacuum pressure. Also, the supporting unit30is to have a low outgassing rate and a low water absorption rate so as to maintain the vacuum state. Further, the supporting unit30is to have a low thermal conductivity so as to reduce heat conduction between the plate members. Furthermore, the supporting unit30is to secure the compressive strength at a high temperature so as to endure a high-temperature exhaust process. Additionally, the supporting unit30is to have an excellent machinability so as to be subjected to molding. Also, the supporting unit30is to have a low cost for molding. A time required to perform the exhaust process takes about a few days. Hence, the time is reduced, thereby considerably improving fabrication cost and productivity. Therefore, the compressive strength is to be secured at the high temperature because an exhaust speed is increased as a temperature at which the exhaust process is performed becomes higher. The inventor has performed various examinations under the above-described conditions.

First, ceramic or glass has a low outgassing rate and a low water absorption rate, but its machinability is remarkably lowered. Hence, the ceramic and glass may not be used as the material of the supporting unit30. Therefore, resin may be considered as the material of the supporting unit30.

FIG.4is a diagram illustrating results obtained by examining resins. Referring toFIG.4, the present inventor has examined various resins, and most of the resins cannot be used because their outgassing rates and water absorption rates are remarkably high. Accordingly, the present inventor has examined resins that approximately satisfy conditions of the outgassing rate and the water absorption rate. As a result, polyethylene resin (PE) is inappropriate to be used due to its high outgassing rate and its low compressive strength. Polychlorotrifluoroethylene (PCTFE) is not used due to its remarkably high price. Polyether ether ketone (PEEK) is inappropriate to be used due to its high outgassing rate. Accordingly, it is determined that that a resin selected from the group consisting of polycarbonate (PC), glass fiber PC, low outgassing PC, polyphenylene sulfide (PPS), and liquid crystal polymer (LCP) may be used as the material of the supporting unit. However, an outgassing rate of the PC is 0.19, which is at a low level. Hence, as the time required to perform baking in which exhaustion is performed by applying heat is increased to a certain level, the PC may be used as the material of the supporting unit.

The present inventor has found an optimal material by performing various studies on resins expected to be used inside the vacuum space part. Hereinafter, results of the performed studies will be described with reference to the accompanying drawings.

FIG.5is a view illustrating results obtained by performing an experiment on vacuum maintenance performances of the resins. Referring toFIG.5, there is illustrated a graph showing results obtained by fabricating the supporting unit using the respective resins and then testing vacuum maintenance performances of the resins. First, a supporting unit fabricated using a selected material was cleaned using ethanol, left at a low pressure for 48 hours, exposed to air for 2.5 hours, and then subjected to an exhaust process at 90° C. for about 50 hours in a state that the supporting unit was put in the vacuum adiabatic body, thereby measuring a vacuum maintenance performance of the supporting unit.

It may be seen that in the case of the LCP, its initial exhaust performance is best, but its vacuum maintenance performance is bad. It may be expected that this is caused by sensitivity of the LCP to temperature. Also, it is expected through characteristics of the graph that, when a final allowable pressure is 5×10-3 Torr, its vacuum performance will be maintained for a time of about 0.5 year. Therefore, the LCP is inappropriate as the material of the supporting unit.

It may be seen that, in the case of the glass fiber PC (G/F PC), its exhaust speed is fast, but its vacuum maintenance performance is low. It is determined that this will be influenced by an additive. Also, it is expected through the characteristics of the graph that the glass fiber PC will maintain its vacuum performance will be maintained under the same condition for a time of about 8.2 years. Therefore, the LCP is inappropriate as the material of the supporting unit.

It is expected that, in the case of the low outgassing PC (L/O PC), its vacuum maintenance performance is excellent, and its vacuum performance will be maintained under the same condition for a time of about 34 years, as compared with the above-described two materials. However, it may be seen that the initial exhaust performance of the low outgassing PC is low, and therefore, fabrication efficiency of the low outgassing PC is lowered.

It may be seen that, in the case of the PPS, its vacuum maintenance performance is remarkably excellent, and its exhaust performance is also excellent. Therefore, it is considered that, based on the vacuum maintenance performance, the PPS is used as the material of the supporting unit.

FIGS.6A-6Cillustrate results obtained by analyzing components of gases discharged from the PPS and the low outgassing PC, in which the horizontal axis represents mass numbers of gases and the vertical axis represents concentrations of gases.FIG.6Aillustrates a result obtained by analyzing a gas discharged from the low outgassing PC. InFIG.6A, it may be seen that H2series (I), H2O series (II), N2/CO/CO2/O2series (III), and hydrocarbon series (IV) are equally discharged.FIG.6Billustrates a result obtained by analyzing a gas discharged from the PPS. InFIG.6B, it may be seen that H2series (I), H2O series (II), and N2/CO/CO2/O2series (III) are discharged to a weak extent.FIG.6Cis a result obtained by analyzing a gas discharged from stainless steel. InFIG.6C, it may be seen that a similar gas to the PPS is discharged from the stainless steel. Consequently, it may be seen that the PPS discharges a similar gas to the stainless steel. As the analyzed result, it may be re-confirmed that the PPS is excellent as the material of the supporting unit.

FIG.7illustrates results obtained by measuring maximum deformation temperatures at which resins are damaged by atmospheric pressure in high-temperature exhaustion. The bars31were provided at a diameter of 2 mm at a distance of 30 mm. Referring toFIG.7, it may be seen that a rupture occurs at 60° C. in the case of the PE, a rupture occurs at 90° C. in the case of the low outgassing PC, and a rupture occurs at 125° C. in the case of the PPS. As the analyzed result, it may be seen that the PPS is most used as the resin used inside of the vacuum space part. However, the low outgassing PC may be used in terms of fabrication cost.

A radiation resistance sheet32for reducing heat radiation between the first and second plate members10and20through the vacuum space part50will be described. The first and second plate members10and20may be made of a stainless material capable of preventing corrosion and providing a sufficient strength. The stainless material has a relatively high emissivity of 0.16, and hence a large amount of radiation heat may be transferred. In addition, the supporting unit30made of the resin has a lower emissivity than the plate members, and is not entirely provided to inner surfaces of the first and second plate members10and20. Hence, the supporting unit30does not have great influence on radiation heat. Therefore, the radiation resistance sheet32may be provided in a plate shape over a majority of the area of the vacuum space part50so as to concentrate on reduction of radiation heat transferred between the first and second plate members10and20. A product having a low emissivity may be used as the material of the radiation resistance sheet32. In an embodiment, an aluminum foil having an emissivity of 0.02 may be used as the radiation resistance sheet32. Also, as the transfer of radiation heat may not be sufficiently blocked using one radiation resistance sheet, at least two radiation resistance sheets32may be provided at a certain distance so as not to contact each other. Also, at least one radiation resistance sheet may be provided in a state in which it contacts the inner surface of the first or second plate member10or20.

Referring back toFIG.3B, a distance between the plate members is maintained by the supporting unit30, and a porous material33may be filled in the vacuum space part50. The porous material33may have a higher emissivity than the stainless material of the first and second plate members10and20. However, as the porous material33is filled in the vacuum space part50, the porous material33has a high efficiency for resisting the radiation heat transfer.

FIGS.8A-8Care views showing various embodiments of conductive resistance sheets and peripheral parts thereof. Structures of the conductive resistance sheets are briefly illustrated inFIG.2, but will be understood in detail with reference to the drawings.

First, a conductive resistance sheet proposed inFIG.8Amay be applied to the main body-side vacuum adiabatic body. Specifically, the first and second plate members10and20are to be sealed so as to vacuumize the interior of the vacuum adiabatic body. In this case, as the two plate members have different temperatures from each other, heat transfer may occur between the two plate members. Conductive resistance sheet60is provided to prevent heat conduction between two different kinds of plate members.

The conductive resistance sheet60may be provided with sealing parts61at which both ends of the conductive resistance sheet60are sealed to defining at least one portion of the wall for the third space and maintain the vacuum state. The conductive resistance sheet60may be provided as a thin foil in unit of micrometer so as to reduce the amount of heat conducted along the wall for the third space. The sealing parts610may be provided as welding parts. That is, the conductive resistance sheet60and the plate members10and20may be fused to each other. In order to cause a fusing action between the conductive resistance sheet60and the plate members10and20, the conductive resistance sheet60and the plate members10and20may be made of the same material, and a stainless material may be used as the material. The sealing parts610are not limited to the welding parts, and may be provided through a process, such as cocking. The conductive resistance sheet60may be provided in a curved shape. Thus, a heat conduction distance of the conductive resistance sheet60is provided longer than a linear distance of each plate member, so that the amount of heat conduction may be further reduced.

A change in temperature occurs along the conductive resistance sheet60. Therefore, in order to block heat transfer to the exterior of the conductive resistance sheet60, a shielding part (shield)62may be provided at an exterior of the conductive resistance sheet60such that an adiabatic action occurs. In other words, in the refrigerator, the second plate member20has a high temperature and the first plate member10has a low temperature. In addition, heat conduction from high temperature to low temperature occurs in the conductive resistance sheet60, and hence, the temperature of the conductive resistance sheet60is suddenly changed. Therefore, when the conductive resistance sheet60is opened to the exterior thereof, heat transfer through the opened place may seriously occur. In order to reduce heat loss, the shielding part62is provided at the exterior of the conductive resistance sheet60. For example, when the conductive resistance sheet60is exposed to any one of the low-temperature space and the high-temperature space, the conductive resistance sheet60does not serve as a conductive resistor as well as the exposed portion thereof.

The shielding part62may be provided as a porous material contacting an outer surface of the conductive resistance sheet60. The shielding part62may be provided as an adiabatic structure, e.g., a separate gasket, which is placed at the exterior of the conductive resistance sheet60. The shielding part62may be provided as a portion of the vacuum adiabatic body, which is provided at a position facing a corresponding conductive resistance sheet60when the main body-side vacuum adiabatic body is closed with respect to the door-side vacuum adiabatic body. In order to reduce heat loss even when the main body and the door are opened, the shielding part62may be provided as a porous material or a separate adiabatic structure.

A conductive resistance sheet proposed inFIG.8Bmay be applied to the door-side vacuum adiabatic body. InFIG.8B, portions different from those ofFIG.8Aare described, and the same description is applied to portions identical to those ofFIG.8A. A side frame70is further provided at an outside of the conductive resistance sheet60. A part for sealing between the door and the main body, an exhaust port necessary for an exhaust process, a getter port for vacuum maintenance, for example, may be placed on the side frame70. This is because mounting of parts is convenient in the main body-side vacuum adiabatic body, but mounting positions of parts are limited in the door-side vacuum adiabatic body.

In the door-side vacuum adiabatic body, it is difficult to place the conductive resistance sheet60at a front end portion (front end) of the vacuum space part, i.e., a corner side portion (corner side) of the vacuum space part. This is because, unlike the main body, a corner edge portion (corner edge) of the door is exposed to the exterior. More specifically, if the conductive resistance sheet60is placed at the front end portion of the vacuum space part, the corner edge portion of the door is exposed to the exterior, and hence, there is a disadvantage in that a separate adiabatic part should be configured so as to heat-insulate the conductive resistance sheet60.

A conductive resistance sheet proposed inFIG.8Cmay be installed in the pipeline passing through the vacuum space part. InFIG.8C, portions different from those ofFIGS.8A and8Bare described, and the same description is applied to portions identical to those ofFIGS.8A and8B. A conductive resistance sheet having the same shape as that ofFIG.8A, a wrinkled conductive resistance sheet63may be provided at a peripheral portion of the pipeline64. Accordingly, a heat transfer path may be lengthened, and deformation caused by a pressure difference may be prevented. In addition, a separate shielding part may be provided to improve adiabatic performance of the conductive resistance sheet.

A heat transfer path between the first and second plate members10and20will be described with reference back toFIG.8A. Heat passing through the vacuum adiabatic body may be divided into surface conduction heat conducted along a surface of the vacuum adiabatic body, more specifically, the conductive resistance sheet60, supporter conduction heat conducted along the supporting unit30provided inside of the vacuum adiabatic body, gas conduction heat conducted through an internal gas in the vacuum space part, and radiation transfer heat transferred through the vacuum space part.

The transfer heat may be changed depending on various depending on various design dimensions. For example, the supporting unit may be changed such that the first and second plate members10and20may endure a vacuum pressure without being deformed, the vacuum pressure may be changed, a distance between the plate members may be changed, and a length of the conductive resistance sheet may be changed. The transfer heat may be changed depending on a difference in temperature between the spaces (the first and second spaces) respectively provided by the plate members. In the embodiment, a configuration of the vacuum adiabatic body has been found by considering that its total heat transfer amount is smaller than that of a typical adiabatic structure formed by foaming polyurethane. In a typical refrigerator including the adiabatic structure formed by foaming the polyurethane, an effective heat transfer coefficient may be proposed as 19.6 mW/mK.

By performing a relative analysis on heat transfer amounts of the vacuum adiabatic body of the embodiment, a heat transfer amount by the gas conduction heat may become smallest. For example, the heat transfer amount by the gas conduction heat may be controlled to be equal to or smaller than 4% of the total heat transfer amount. A heat transfer amount by solid conduction heat defined as a sum of the surface conduction heat and the supporter conduction heat is largest. For example, the heat transfer amount by the solid conduction heat may reach 75% of the total heat transfer amount. A heat transfer amount by the radiation transfer heat is smaller than the heat transfer amount by the solid conduction heat but larger than the heat transfer amount of the gas conduction heat. For example, the heat transfer amount by the radiation transfer heat may occupy about 20% of the total heat transfer amount.

According to such a heat transfer distribution, effective heat transfer coefficients (eK: effective K) (W/mK) of the surface conduction heat, the supporter conduction heat, the gas conduction heat, and the radiation transfer heat may have an order of Math Equation 1.
eKsolid conduction heat>eKradiation transfer heat>eKgas conduction heat  [Equation 1]

Here, the effective heat transfer coefficient (eK) is a value that may be measured using a shape and temperature differences of a target product. The effective heat transfer coefficient (eK) is a value that may be obtained by measuring a total heat transfer amount and a temperature at least one portion at which heat is transferred. For example, a calorific value (W) is measured using a heating source that may be quantitatively measured in the refrigerator, a temperature distribution (K) of the door is measured using heats respectively transferred through a main body and an edge of the door of the refrigerator, and a path through which heat is transferred is calculated as a conversion value (m), thereby evaluating an effective heat transfer coefficient.

The effective heat transfer coefficient (eK) of the entire vacuum adiabatic body is a value given by k=QL/AΔT. Here, Q denotes a calorific value (W) and may be obtained using a calorific value of a heater. A denotes a sectional area (m2) of the vacuum adiabatic body, L denotes a thickness (m) of the vacuum adiabatic body, and ΔT denotes a temperature difference.

For the surface conduction heat, a conductive calorific value may be obtained through a temperature difference (ΔT) between an entrance and an exit of the conductive resistance sheet60or63, a sectional area (A) of the conductive resistance sheet, a length (L) of the conductive resistance sheet, and a thermal conductivity (k) of the conductive resistance sheet (the thermal conductivity of the conductive resistance sheet is a material property of a material and may be obtained in advance). For the supporter conduction heat, a conductive calorific value may be obtained through a temperature difference (ΔT) between an entrance and an exit of the supporting unit30, a sectional area (A) of the supporting unit, a length (L) of the supporting unit, and a thermal conductivity (k) of the supporting unit. Here, the thermal conductivity of the supporting unit is a material property of a material and may be obtained in advance. The sum of the gas conduction heat, and the radiation transfer heat may be obtained by subtracting the surface conduction heat and the supporter conduction heat from the heat transfer amount of the entire vacuum adiabatic body. A ratio of the gas conduction heat, and the radiation transfer heat may be obtained by evaluating radiation transfer heat when no gas conduction heat exists by remarkably lowering a vacuum degree of the vacuum space part50.

When a porous material is provided inside the vacuum space part50, porous material conduction heat may be a sum of the supporter conduction heat and the radiation transfer heat. The porous material conduction heat may be changed depending on various variables including a kind, and an amount, for example, of the porous material.

According to an embodiment, a temperature difference ΔT1between a geometric center formed by adjacent bars31and a point at which each of the bars31is located may be provided to be less than 0.5° C. Also, a temperature difference ΔT2between the geometric center formed by the adjacent bars31and an edge portion of the vacuum adiabatic body may be provided to be less than 0.5° C. In the second plate member20, a temperature difference between an average temperature of the second plate and a temperature at a point at which a heat transfer path passing through the conductive resistance sheet60or63meets the second plate may be largest. For example, when the second space is a region hotter than the first space, the temperature at the point at which the heat transfer path passing through the conductive resistance sheet meets the second plate member becomes lowest. Similarly, when the second space is a region colder than the first space, the temperature at the point at which the heat transfer path passing through the conductive resistance sheet meets the second plate member becomes highest.

This means that the amount of heat transferred through other points except the surface conduction heat passing through the conductive resistance sheet should be controlled, and the entire heat transfer amount satisfying the vacuum adiabatic body may be achieved only when the surface conduction heat occupies the largest heat transfer amount. To this end, a temperature variation of the conductive resistance sheet may be controlled to be larger than that of the plate member.

Physical characteristics of the parts constituting the vacuum adiabatic body will be described. In the vacuum adiabatic body, a force by vacuum pressure is applied to all of the parts. Therefore, a material having a strength (N/m2) of a certain level may be used.

Under such circumferences, the plate members10and20and the side frame70may be made of a material having a sufficient strength with which they are not damaged by even vacuum pressure. For example, when the number of bars31is decreased so as to limit support conduction heat, deformation of the plate member occurs due to the vacuum pressure, which may negatively influence the external appearance of refrigerator. The radiation resistance sheet32may be made of a material that has a low emissivity and may be easily subjected to thin film processing. Also, the radiation resistance sheet32is to ensure a sufficient strength not to be deformed by an external impact. The supporting unit30is provided with a strength sufficient so as to support the force of the vacuum pressure and endure an external impact, and is to have machinability. The conductive resistance sheet60may be made of a material that has a thin plate shape and may endure the vacuum pressure.

In an embodiment, the plate member, the side frame, and the conductive resistance sheet may be made of stainless materials having the same strength. The radiation resistance sheet may be made of aluminum having a weaker strength that the stainless materials. The supporting unit may be made of resin having a weaker strength than the aluminum.

Unlike the strength from the point of view of materials, analysis from the point of view of stiffness is required. The stiffness (N/m) is a property that would not be easily deformed. Although the same material is used, its stiffness may be changed depending on its shape. The conductive resistance sheets60or63may be made of a material having a strength, but the stiffness of the material is low so as to increase heat resistance and minimize radiation heat as the conductive resistance sheet is uniformly spread without any roughness when the vacuum pressure is applied. The radiation resistance sheet32requires a stiffness of a certain level so as not to contact another part due to deformation. Particularly, an edge portion (edge) of the radiation resistance sheet may generate conduction heat due to drooping caused by self-load of the radiation resistance sheet. Therefore, a stiffness of a certain level is required. The supporting unit30requires a stiffness enough to endure a compressive stress from the plate member and an external impact.

In an embodiment, the plate member and the side frame may have the highest stiffness so as to prevent deformation caused by the vacuum pressure. The supporting unit, particularly, the bar may have the second highest stiffness. The radiation resistance sheet may have a stiffness that is lower than that of the supporting unit but higher than that of the conductive resistance sheet. Lastly, the conductive resistance sheet may be made of a material that is easily deformed by the vacuum pressure and has the lowest stiffness. Even when the porous material33is filled in the vacuum space part the conductive resistance sheet may have the lowest stiffness, and the plate member and the side frame may have the highest stiffness.

The vacuum space part50may resist heat transfer by only the supporting unit30. A porous material33may be filled within the supporting unit30inside of the vacuum space part50to resist heat transfer. The heat transfer to the porous material33may resist without applying the supporting unit30.

In the above description, as a material suitable for the supporting unit, a resin of PPS has been proposed. The bar31is provided on the support plate35at intervals of 2 cm to 3 cm, and the bar31has a height of 1 cm to 2 cm. These resins often have poor fluidity of the resin during molding. In many cases, the molded article does not have design value. Particularly, a shape of a molded product, such as a bar having a short length, is often not provided properly due to non-uniform injection of resin into a part far from a liquid injection port. This may cause damage to the supporting unit or a defective vacuum adiabatic body later.

The supporting unit30is a substantially two-dimensional structure, but its area is considerably large. Therefore, if a defect occurs in one of the portions, it is difficult to discard the entire structure. This limitation becomes even more pronounced as refrigerators and warming apparatus are becoming larger in size to meet the needs of consumers.

Hereinafter, a supporting unit for solving the above-described limitation will be described.

FIG.9is a view illustrating any one side portion of the supporting unit according an embodiment. Referring toFIG.9, one (first) side support plate350is provided with at least two partial plates coupled to each other. In other words, partial plates having a small rectangular shape are coupled to each other to provide one side support plate350having a large rectangular shape. For example, in the drawings, a second partial plate352and a fourth partial plate354are coupled to lower and right sides of a first partial plate351. The second partial plate352and the fourth partial plate354are coupled to left and upper sides of a third partial plate353.

In an embodiment, the partial plates may have a same shape. Thus, a size of one side support plate350may reach four times the size of the partial plate. When varying the number of partial plates351,352,353and354, which have the same shape and structure to be coupled to each other, the size of the one side support plate350may be changed. It is easily guessed that the size of the one side support plate350is differently provided depending on a size of the vacuum adiabatic body.

According to this configuration, the partial plate may be manufactured using resin having a poor fluidity when the partial plate is a liquid such as PPS, and the partial plate may be coupled. As the partial plate is small in size, defects may be prevented during molding, and even if a molding failure occurs, only the corresponding partial plate is discarded, so that it is not necessary to discard the whole support plate.

After producing the small partial plate, it is assembled at an assembly site of the vacuum adiabatic body and then put into the vacuum adiabatic body. Thus, there is an advantage that handling and transportation are convenient. In addition, it may be possible to prevent damage which may occur during handling of the large parts.

A plurality of small partial plates may be produced, and various types of supporting units having a desired area may be obtained.

FIG.10is a plan view of the partial plate. Referring toFIG.10, the partial plate351has one side base (base)355of a lattice structure, and a column356provided at a crossing point of the lattice on the one side base355. The one side base355may maintain the vacuum space inside of the plate members10and20by contacting inner surfaces of the plate members10and20. The column356may provide a portion of the bar31to maintain an interval between the plate members10and20.

A mesh end of the lattice structure constituting the one base351may have a male and female coupling structure for coupling different partial plates351to each other. For example, upper and left edges may have a male coupling structure, and right and lower edges may have a female coupling structure. Extension lines of arrows in the drawings indicate edges having the same coupling structure.

FIG.11is an enlarged view of a portion A ofFIG.10.FIG.12is an enlarged view of a portion B ofFIG.10.

Referring toFIGS.11and12, the male coupling structure (seeFIG.11) has an insertion part357at an end of a branch that provides the lattice of one base (base)355. The insertion part357may be provided in a structure in which the end of the branch is extended. The male coupling structure (seeFIG.12) may be provided with a holding part358which is held at the end of the one base355. A holding part358may be provided with a recess359at the end of the branch. The shape of the recess359may be provided in a shape corresponding to the insertion part357. The insertion part357may be inserted into the recess359.

The male coupling structure of the adjacent partial plate is vertically aligned with the female coupling structure of the other partial plate, and the insertion part357and the recess359are used as a reference for vertical alignment. Thereafter, when the insertion part357is moved in the vertical direction to the recess359, coupling between the partial plates may be completed. The vertical direction may be a direction perpendicular to the plane of a corresponding plate member.

For example, right and lower side male coupling structures of the first partial plate351are coupled to the male coupling structure of the fourth partial plate354and the male coupling structure of the second partial plate352. This coupling structure may be the same for other partial plates.

The male coupling structure and the female coupling structure of the partial plates allow for use of as small a quantity of resin as possible and are intended to enable coupling while reducing size as much as possible. Movement in one direction, i.e., up and down direction, is permitted to be coupled. However, movement in the two-dimensional direction, i.e., in the area direction is not allowed, so that the coupling is performed.

The male coupling structure and the female coupling structure do not need to be completely fitted to each other, e.g., they are coupled to each other. This is because not only the movement in the two-dimensional direction but also the vertical movement of the respective partial plates is permitted, but the vertical movements are fixed later by a separate member. Also, this is because of characteristics of resin having poor liquid fluidity, it is necessary to make it easy to couple slight loose coupling through movement in the up and down direction through the coupling. That is, this is because a numerical value of the coupling structure for press-fitting may lead to damage to the partial plate at the time of coupling.

This structure reduces an amount of resin as much as possible to reduce an amount of outgasing so as not to cause the limitation in vacuum maintenance of the vacuum space part and to prevent molding of the male coupling structure and the female coupling structure from being difficult even if the resin having poor formability is used.

FIG.13is an enlarged view of a portion C ofFIG.9. Referring toFIG.13, in the case of the embodiment, all of the partial plates are in contact with each other, and the partial plates have the same shape. The insertion part357is fixed to the holding part358in a vertical direction. The holding parts358and357provided on the respective partial plates351,352,353and354are coupled to each other so that movement of the partial plates in the two-dimensional direction, i.e., one support plate350may provide a large area. The area of the one side support plate350may be achieved by coupling a necessary number of partial plates. When varying the size and number of the partial plates, the sizes of the one side support plates350having various shapes and sizes may be obtained.

The column356provided at the intersection of the respective lattices constituting the one base355may include two types. For example, the columns356may include a spacing (first) column3561that functions to maintain an interval between the plate members10and20and a support (second) column3562that supports the radiation resistance sheet32.

The spacing column3561is coupled to a groove (see reference numeral373inFIG.16) of the other support plate (see reference numeral370inFIG.14) to maintain the interval between the plate members10and20. In order to facilitate coupling with the groove373and to ensure moldability using liquid resin, the spacing column3561is provided with a diameter H1at a lower end of the spacing column, which is greater than a diameter H2at an upper end. Although the cross-sectional shape of the spacing column3561may not be circular, the cross-sectional size of the upper end may be small. However, the cross-sectional shape of the spacing column3561may be provided in a circular shape in order to secure the forming shape of the spacing columns3561and the coupling between the spacing columns3561and the groove373.

As in the case of the spacing column3561, the support column3562has a smaller cross-sectional size of the support column3562toward the upper end for securing coupling and moldability. Further, for supporting the radiation resistance sheet32, the support column3562may be provided with a stepped protrusion3563. A plurality of support columns3562may be provided at predetermined intervals to stably support the radiation resistance sheet32. The action of the support column3562will be described in more detail below.

As has been described above, movement of the one side support plate350in the vertical direction is restricted while the one side support plate350is free to move in the vertical direction. Therefore, a configuration for limiting the vertical movement of each partial plate may be provided. The supporting unit30may be in contact with the inner surface of the plate member to support the interval of the plate members10and20. When the supporting unit is in contact with the plate member, point contact may provide a stable supporting force as compared with line contact. Therefore, a configuration may be provided such that the column356does not directly contact the inner surface of the plate member.

In order to achieve this object, another side support plate370corresponding to the one side support plate350may be further provided. Hereinafter, the one side support plate350and the other side support plate370will be described.

FIG.14is a view for explaining coupling between one side support plate and the other side support plate. Referring toFIG.14, at least two of the partial plates are coupled to each other to provide the one side support plate350. The one side support plate350is restricted to separate in the area (lateral) direction, but the upward and downward (vertical) movement is not restricted. In order to restrict vertical separation of the one side support plate350and securely secure the interval of the plate members10and20while more strongly coupling the one side support plate350in the direction of the area separation, a support plate370is provided. The other side support plate370may be coupled to the one side support plate350.

The other side support plate370may be understood as a member for supporting the plate member opposite to the plate member supported by the one side support plate350. The other side support plate370may be used as it is with a standardized other side plate member having a predetermined size, or a standardized side plate member may be separated at a proper position by cutting, for example. Therefore, it may be understood that the other plate member has the same configuration, but the applied area is different.

Of course, the other side plate member as a unit having an area corresponding to the one side support plate350may be provided, but a same constitution as the embodiment may be presented in order to maximize the effect as a part.

In an embodiment, the other side plate member of the original size which is not cut is formed at a center portion of the one side support plate350at which the partial plates351,352,353and354are coupled to each other as overlapping other side plates (boundary support plate)371. In this case, the other plate member is coupled to overlap a boundary of the different partial plates, thereby enhancing a binding force between the respective partial plates and performing the function of restricting movement in the area direction. In this case, it is needless to say that the function of restricting the movement of the partial plate in the vertical direction and the function of maintaining the interval of the plate members10and20are performed.

In other words, the boundary of each partial plate constituting one support plate and the other plate member constituting the other support plate (which may include both of the overlapping other plate and the single other plate) cross each other and do not overlap each other desirable. If the boundaries overlap each other, there is a possibility that the members of the respective support plates, i.e., the partial plate and the other plate member are separated from each other independently or together.

The other plate member may be provided in the same shape as the overlapping plate371coupled to the center portion of the one side support plate350. The other plate member may be coupled to the single partial plate without overlapping at least two of the partial plates. In this case, a portion of the other side plate member may be referred to as a single other side plate (secondary support plate)372. In this case, it is needless to say that the function of restricting the movement of the partial plate in the vertical direction and the function of maintaining the interval of the plate members10and20are performed. However, it is not possible to perform the action of restricting movement of each partial plate in the direction of the area and enhancing the binding force between the partial plates.

In the case of an embodiment, four other plate members370having the same area as the partial plates351,352,353, and354may be used. One of the four support plates350is coupled to a center of the other support plate350as the overlapping second side plate371, and two of the four plates are cut horizontally and vertically and coupled as the overlapping second side plate371to correspond to the center of the four edges of the other side support plate350. Among these, the plate which is separated horizontally and vertically is omitted in order to prevent the drawing from being complicated. One of the four plates may be quadrupled and coupled as a single other plate372corresponding to the vertex portion of the other support plate350.

As described above, the other side plate member may include a larger-sized other side plate member and a small-sized side plate member derived from the standardized largest other side plate by separation and transmission. According to this configuration, it is possible to provide the other side support plate of various shapes and structures without providing a separate second side plate member according to the shape and shape of the vacuum adiabatic body.

The arrangement of the partial plate and the other plate member may be an embodiment, and those skilled in the art may suggest other embodiments included in the scope of the same concept.

FIG.15is an enlarged view illustrating a portion D ofFIG.14. Referring toFIG.15, the other side support plate370has a lattice-shaped other side base378like the one side support plate350and a groove373which is coupled to the column356at the intersection of the lattice of the other side base378.

A radiation resistance sheet32may be supported between the stepped protrusion3563and the groove373. Upper and lower positions of the radiation resistance sheet32may be restrained between the groove373and the end of the stepped protrusion3563and the movement in the direction of the area may be restricted by the support columns3562.

FIG.16is a cross-sectional view taken along line XVI-XVI′ ofFIG.15. Referring toFIG.16, a support position of the radiation resistance sheet32in the vertical direction is restricted between the stepped protrusion3563and the groove373. For this purpose, the size of the hole provided in the radiation resistance sheet32is smaller than the size of the end of the stepped protrusion3563and the size of the end of the groove373.

The vacuum adiabatic body may be manufactured in various sizes, and shapes. For example, the vacuum adiabatic body provided on the wall of the large refrigerator will be provided in a large plane, and the vacuum adiabatic body provided on the wall of the small refrigerator may be provided in a small plane.

It is not advantageous to manufacture the respective support plates in order to cope with refrigerator sizes of various shapes as described above because the cost of the products increases. This is because part stocks are increasing due to inability of parts to be shared, and it is difficult to procure parts in the right place in response to demand. In order to cope with this limitation, the present inventor has proposed to utilize the partial plates351,352,353, and354, but it has been difficult to cope with vacuum adiabatic bodies having various sizes by the partial plate concept alone.

FIG.17is a view of a supporting unit according to another embodiment. Referring toFIG.17, the one side (first) support plate3500and the other side (second) support plate3700may be manufactured as two kinds of partial plates. The partial plate may include a first type partial plate4001having a lateral length ratio of 3:5 and a second type partial plate4002having a lateral length ratio of 4:10. Length ratios of the partial plates4001and4002may vary, but are merely examples. In addition, although support plates having a length ratio of 1:1 in the left and right (lateral) directions are assumed in the drawings, the embodiment is not limited thereto, and it is possible to provide a support plate having various shapes and sizes according to a combination of two partial plates.

The one side support plate3500and the other side support plate3700may be provided in a state of being rotated by 90 degrees from each other. Due to such a configuration, it is possible to prevent lowering of a coupling force at a portion at which the partial plate is connected.

The coupling between the one side support plate3500and the partial plate placed inside of the other side support plate3700may be applied as it is in the embodiments already described.

In this embodiment, when a virtual line A-A is drawn in a direction along edges of the one side support plate3500and the other side support plate3700, the following features are revealed. In the figures, imaginary lines are considered on the other support plate. Similar results may be obtained for one side support plate.

First, at least two partial plates in the line through which the imaginary line passes are the same. In an embodiment, there are two first type partial plates4001. This may have a technical meaning to increase commonality of parts. That is, as at least two identical partial plates are used, mass production of the same partial plate may be induced.

Second, all of the partial plates are not the same in the line through which the imaginary line passes. In the embodiment, not only the first type partial plate4001but also the second partial plate4002were used. This is a technical idea necessary for obtaining one side or the other side support plate having various shapes and areas.

Third, at least two kinds of partial plates are used in the line through which the imaginary line passes. According to this, it is possible to provide a more various one side or the other side support plate, so that it is possible to cope with vacuum adiabatic body of various shapes and sizes. By using the two partial plates, it is expected that vacuum adiabatic bodies having various shapes and sizes at present may be manufactured while achieving commonality of the partial plates. According to the present embodiment, it may be seen that the cost is reduced by more actively sharing components with respect to vacuum heat insulating bodies of various shapes and sizes.

Hereinafter, vacuum pressure of the vacuum adiabatic body will be described.

FIG.18illustrates graphs showing changes in adiabatic performance and changes in gas conductivity with respect to vacuum pressures by applying a simulation. Referring toFIG.18, it may be seen that, as the vacuum pressure is decreased, i.e., as the vacuum degree is increased, a heat load in the case of only the main body (Graph1) or in the case where the main body and the door are joined together (Graph2) is decreased as compared with that in the case of the typical product formed by foaming polyurethane, thereby improving adiabatic performance. However, it may be seen that a degree of improvement of the adiabatic performance is gradually lowered. Also, it may be seen that, as the vacuum pressure is decreased, gas conductivity (Graph3) is decreased. However, it may be seen that, although the vacuum pressure is decreased, a ratio at which the adiabatic performance and the gas conductivity are improved is gradually lowered. Therefore, the vacuum pressure is decreased as low as possible. However, it takes a long time to obtain excessive vacuum pressure, and much cost is consumed due to excessive use of a getter. In the embodiment, an optimal vacuum pressure is proposed from the above-described point of view.

FIG.19is a graph illustrating results obtained by observing a time and a pressure in a process of exhausting the inside of the vacuum adiabatic body when a supporting unit is used. Referring toFIG.19, in order to create the vacuum space part50to be in the vacuum state, a gas in the vacuum space part50is exhausted by a vacuum pump while evaporating a latent gas remaining in parts of the vacuum space part50through baking. However, if the vacuum pressure reaches a certain level or more, there exists a point at which the level of the vacuum pressure is not increased any more (ΔT1). After that, the getter is activated by disconnecting the vacuum space part50from the vacuum pump and applying heat to the vacuum space part50(ΔT2). If the getter is activated, the pressure in the vacuum space part50is decreased for a certain period of time, but then normalized to maintain a vacuum pressure of a certain level. The vacuum pressure that maintains the certain level after activation of the getter is approximately 1.8×10-6 Torr.

In the embodiment, a point at which the vacuum pressure is not substantially decreased any more even though the gas is exhausted by operating the vacuum pump is set to a lowest limit of the vacuum pressure used in the vacuum adiabatic body, thereby setting a minimum internal pressure of the vacuum space part50to 1.8×10-6 Torr.

FIG.20is a graph obtained by comparing a vacuum pressure with gas conductivity. Referring toFIG.20, gas conductivities with respect to vacuum pressures depending on sizes of a gap in the vacuum space part50are represented as graphs of effective heat transfer coefficients (eK). Effective heat transfer coefficients (eK) were measured when the gap in the vacuum space part50has three sizes of 2.76 mm, 6.5 mm, and 12.5 mm. The gap in the vacuum space part50is defined as follows. When the radiation resistance sheet32exists inside of the vacuum space part50, the gap is a distance between the radiation resistance sheet32and the plate member adjacent thereto. When the radiation resistance sheet32does not exist inside of the vacuum space part50, the gap is a distance between the first and second plate members.

It was seen that, as the size of the gap is small at a point corresponding to a typical effective heat transfer coefficient of 0.0196 W/mK, which is provided to an adiabatic material formed by foaming polyurethane, the vacuum pressure is 2.65×10-1 Torr even when the size of the gap is 2.76 mm. It was seen that the point at which reduction in adiabatic effect caused by gas conduction heat is saturated even though the vacuum pressure is decreased is a point at which the vacuum pressure is approximately 4.5×10-3 Torr. The vacuum pressure of 4.5×10-3 Torr may be defined as the point at which the reduction in adiabatic effect caused by gas conduction heat is saturated. Also, when the effective heat transfer coefficient is 0.1 W/mK, the vacuum pressure is 1.2×10-2 Torr.

When the vacuum space part50is not provided with the supporting unit but provided with the porous material, the size of the gap ranges from a few micrometers to a few hundreds of micrometers. In this case, the amount of radiation heat transfer is small due to the porous material even when the vacuum pressure is relatively high, i.e., when the vacuum degree is low. Therefore, an appropriate vacuum pump is used to adjust the vacuum pressure. The vacuum pressure appropriate to the corresponding vacuum pump is approximately 2.0×10-4 Torr. Also, the vacuum pressure at the point at which the reduction in adiabatic effect caused by gas conduction heat is saturated is approximately 4.7×10-2 Torr. Also, the pressure where the reduction in adiabatic effect caused by gas conduction heat reaches the typical effective heat transfer coefficient of 0.0196 W/mK is 730 Torr.

When the supporting unit and the porous material are provided together in the vacuum space part, a vacuum pressure may be created and used, which is in the middle between the vacuum pressure when only the supporting unit is used and the vacuum pressure when only the porous material is used.

In the description of embodiments, a part for performing the same action in each embodiment of the vacuum adiabatic body may be applied to another embodiment by properly changing the shape or dimension of foregoing another embodiment. Accordingly, still another embodiment may be easily proposed. For example, in the detailed description, in the case of a vacuum adiabatic body suitable as a door-side vacuum adiabatic body, the vacuum adiabatic body may be applied as a main body-side vacuum adiabatic body by properly changing the shape and configuration of a vacuum adiabatic body.

The vacuum adiabatic body proposed in embodiments may be applied to refrigerators. However, the application of the vacuum adiabatic body is not limited to the refrigerators, and may be applied in various apparatuses, such as cryogenic refrigerating apparatuses, heating apparatuses, and ventilation apparatuses.

According to embodiments, the vacuum adiabatic body may be industrially applied to various adiabatic apparatuses. The adiabatic effect may be enhanced, so that it is possible to improve energy use efficiency and to increase the effective volume of an apparatus.

Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.