Patent Description:
A vacuum adiabatic body is a product for suppressing heat transfer by vacuumizing the interior of a body thereof. The vacuum adiabatic body may reduce heat transfer by convection and conduction, and hence is applied to heating apparatuses and refrigerating apparatuses. In a typical adiabatic method applied to a refrigerator, although it is differently applied in refrigeration and freezing, a foam urethane adiabatic wall having a thickness of about <NUM> or more is generally provided. However, the internal volume of the refrigerator is therefore reduced.

In order to increase the internal volume of a refrigerator, there is an attempt to apply a vacuum adiabatic body to the refrigerator.

First, <CIT> (Reference Document <NUM>) of the present applicant has been disclosed. According to Reference Document <NUM>, there is disclosed a method in which a vacuum adiabatic panel is prepared and then built in walls of a refrigerator, and the exterior of the vacuum adiabatic panel is finished with a separate molding as Styrofoam. According to the method, additional foaming is not required, and the adiabatic performance of the refrigerator is improved. However, fabrication cost is increased, and a fabrication method is complicated. As another example, a technique of providing walls using a vacuum adiabatic material and additionally providing adiabatic walls using a foam filling material has been disclosed in <CIT> (Reference Document <NUM>). According to Reference Document <NUM>, fabrication cost is increased, and a fabrication method is complicated.

As further another example, there is an attempt to fabricate all walls of a refrigerator using a vacuum adiabatic body that is a single product. For example, a technique of providing an adiabatic structure of a refrigerator to be in a vacuum state has been disclosed in U. Patent Laid-Open Publication No. <CIT> (Reference Document <NUM>). However, it is difficult to obtain a practical level of an adiabatic effect by providing a wall of the refrigerator with sufficient vacuum. In detail, there are limitations that it is difficult to prevent a heat transfer phenomenon at a contact portion between an outer case and an inner case having different temperatures, it is difficult to maintain a stable vacuum state, and it is difficult to prevent deformation of a case due
to a negative pressure of the vacuum state. Due to these limitations, the technology disclosed in Reference Document <NUM> is limited to a cryogenic refrigerator, and does not provide a level of technology applicable to general households.

The present applicant had filed Patent Application No. <CIT> (Cited document <NUM>) in consideration of the above-described limitations. In the above document, a refrigerator including a vacuum adiabatic body is proposed. Particularly, a resin material that is adequate for a material for forming a supporting unit of the vacuum adiabatic body is proposed.

Even in the above document, it may be difficult to install a radiation resistance sheet on the supporting unit, and when a plurality of radiation resistance sheets are inserted, a separate insertion member for maintaining an interval between the plurality of radiation resistance sheets has to be inserted. A resin material having low outgassing may be selected to deteriorate formability of the supporting unit, and thus, the supporting unit may be damaged during assembly, and productivity may be reduced during the assembly.

<CIT> discloses a vacuum insulator comprising: a heat diffusion block placed in a third space; a thermoelectric module coming into contact with the heat diffusion block so as to exchange heat therewith, and placed in the third space; and a heat sink exchanging heat with the thermoelectric module and placed in a first space or a second space.

<CIT> presents a vacuum insulated panel. A tightly sealed space is formed by disposing a pair of side panels to face each other and disposing four frame pieces along the various sides of the side panels. Using an exhaust port, the tightly sealed space is evacuated. In the tightly sealed space, an inner panel of stainless steel, etc. is disposed to be substantially parallel to the side panels. Multiple protrusions are disposed on the inner panel. As a result of the protrusions contacting the inner surface of the side panel with the tips thereof, the side panels are supported. The protrusions are formed from a material with a lower thermal conductivity than the inner panel such as glass or ceramic.

<CIT> provides an insulation panel having a hollow panel body containing a pair of panels arranged for opposing at regular intervals, a braid connecting the pair of panels on its margin, a spacer arranged in the panel body and an air extraction means contained on arbitrary positions of the panel body to create a vacuum state in the panel body.

<CIT> presents a compact insulation panel which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases therebetween are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. These two metal sheets are textured with ribs or convex bulges in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and various laminates, including wood, porcelain-enameled metal, and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels.

Embodiments also provide a vacuum adiabatic body, which is convenient in installation of a radiation resistance sheet in a supporting unit, and a refrigerator.

Embodiments also provide a vacuum adiabatic body, which prevents a supporting unit from being damaged, and a refrigerator.

The invention is defined by the features of appended claim <NUM>. In order to improve low moldability of a supporting unit, the supporting unit includes a two-dimensional planar structure and crossing the third space and a left bar and a right bar, which respectively extend from both sides of the support to the plate member. The left bar and the right bar may have the same length.

In order to conveniently install a radiation resistance sheet to the supporting unit, the radiation resistance sheet is supported by at least one of the left bar, the right bar, and the support.

In order to prevent the supporting unit from being damaged, an insertion guide may be coupled to the bar. A surface of the insertion guide may have a low frictional structure.

According to the embodiments, the supporting unit may be well maintained in design shape. Thus, the completeness of the product may increase.

According to the embodiments, the radiation resistance sheet may be conveniently installed.

According to the embodiments, the damage of the supporting unit may be reduced to improve the yield of the product.

Hereinafter, exemplary embodiments will be described with reference to the accompanying drawings.

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 of the present invention. It should not be construed as limited.

In the following description, the vacuum pressure means any pressure state lower than the 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> is a perspective view of a refrigerator according to an embodiment.

Referring to <FIG>, the refrigerator <NUM> includes a main body <NUM> provided with a cavity <NUM> capable of storing storage goods and a door <NUM> provided to open/close the main body <NUM>. The door <NUM> may be rotatably or slidably movably disposed to open/close the cavity <NUM>. The cavity <NUM> may provide at least one of a refrigerating compartment and a freezing compartment.

Parts constituting a freezing cycle in which cold air is supplied into the cavity <NUM>. In detail, the parts include a compressor <NUM> for compressing a refrigerant, a condenser <NUM> for condensing the compressed refrigerant, an expander <NUM> for expanding the condensed refrigerant, and an evaporator <NUM> for evaporating the expanded refrigerant to take heat. As a typical structure, a fan may be installed at a position adjacent to the evaporator <NUM>, and a fluid blown from the fan may pass through the evaporator <NUM> and then be blown into the cavity <NUM>. A freezing load is controlled by adjusting the blowing amount and blowing direction by the fan, adjusting the amount of a circulated refrigerant, or adjusting the compression rate of the compressor, so that it is possible to control a refrigerating space or a freezing space.

<FIG> is a view schematically showing a vacuum adiabatic body used in the main body and the door of the refrigerator. In <FIG>, 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 to <FIG>, the vacuum adiabatic body includes a first plate member <NUM> for providing a wall of a low-temperature space, a second plate member <NUM> for providing a wall of a high-temperature space, a vacuum space part <NUM> defined as an interval part between the first and second plate members <NUM> and <NUM>. Also, the vacuum adiabatic body includes the conductive resistance sheets <NUM> and <NUM> for preventing heat conduction between the first and second plate members <NUM> and <NUM>. A sealing part <NUM> for sealing the first and second plate members <NUM> and <NUM> is provided such that the vacuum space part <NUM> is in a sealing state. When the vacuum adiabatic body is applied to a refrigerating or heating cabinet, the first plate member <NUM> may be referred to as an inner case, and the second plate member <NUM> may be referred to as an outer case. A machine room <NUM> in 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 port <NUM> for forming a vacuum state by exhausting air in the vacuum space part <NUM> is provided at any one side of the vacuum adiabatic body. In addition, a pipeline <NUM> passing through the vacuum space part <NUM> may be further installed so as to install a defrosting water line and electric lines.

The first plate member <NUM> may define at least one portion of a wall for a first space provided thereto. The second plate member <NUM> may 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. Here, the wall for each space may serve as not only a wall directly contacting the space but also a wall not contacting the space. For example, the vacuum adiabatic body of the embodiment may also be applied to a product further having a separate wall contacting 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 members <NUM> and <NUM>, heat radiation between the first and second plate members <NUM> and <NUM>, and gas conduction of the vacuum space part <NUM>.

Hereinafter, a heat resistance unit provided to reduce adiabatic loss related to the factors of the heat transfer will be provided. Meanwhile, 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 or the like may be further provided to another side of the vacuum adiabatic body.

<FIG> is a view illustrating various embodiments of an internal configuration of the vacuum space part.

First, referring to <FIG>, the vacuum space part <NUM> may be provided in a third space having a pressure different from that of each of the first and second spaces, preferably, a vacuum state, thereby reducing an adiabatic loss. The third space may be provided at a temperature between the temperature of the first space and the temperature of the second space. Since the third space is provided as a space in the vacuum state, the first and second plate members <NUM> and <NUM> receive 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 part <NUM> may 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 part <NUM>, and an increase in amount of heat conduction, caused by contact between the plate members <NUM> and <NUM>.

The supporting unit <NUM> may be provided to reduce deformation of the vacuum space part <NUM>. The supporting unit <NUM> includes a bar <NUM>. The bar <NUM> may 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 <NUM> may be additionally provided on at least any one end of the bar <NUM>. The support plate <NUM> may connect at least two or more bars <NUM> to each other to extend in a horizontal direction with respect to the first and second plate members <NUM> and <NUM>. The support plate <NUM> 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 member <NUM> or <NUM> decreases, thereby reducing heat transfer. The bars <NUM> and the support plate <NUM> are fixed to each other at at least one portion, to be inserted together between the first and second plate members <NUM> and <NUM>. The support plate <NUM> contacts at least one of the first and second plate members <NUM> and <NUM>, thereby preventing deformation of the first and second plate members <NUM> and <NUM>. In addition, based on the extending direction of the bars <NUM>, a total sectional area of the support plate <NUM> is provided to be greater than that of the bars <NUM>, so that heat transferred through the bars <NUM> may be diffused through the support plate <NUM>.

A material of the supporting unit <NUM> will be described.

The supporting unit <NUM> is to have a high compressive strength so as to endure the vacuum pressure. Also, the supporting unit <NUM> is to have a low outgassing rate and a low water absorption rate so as to maintain the vacuum state. Also, the supporting unit <NUM> is to have a low thermal conductivity so as to reduce the heat conduction between the plate members. Also, the supporting unit <NUM> is to secure the compressive strength at a high temperature so as to endure a high-temperature exhaust process. Also, the supporting unit <NUM> is to have an excellent machinability so as to be subjected to molding. Also, the supporting unit <NUM> is to have a low cost for molding. Here, the 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 unit <NUM>. Therefore, resin may be considered as the material of the supporting unit <NUM>.

<FIG> is a diagram illustrating results obtained by examining resins.

Referring to <FIG>, 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, PE is inappropriate to be used due to its high outgassing rate and its low compressive strength. PCTFE is not preferable to be used due to its remarkably high price. 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 <NUM>, 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> is a view illustrating results obtained by performing an experiment on vacuum maintenance performances of the resins.

Referring to <FIG>, 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 <NUM> hours, exposed to the air for <NUM> hours, and then subjected to an exhaust process at <NUM> for about <NUM> 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 <NUM>×<NUM>-<NUM> Torr, its vacuum performance will be maintained for a time of about <NUM> 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 <NUM> 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 (O/G PC), its vacuum maintenance performance is excellent, and its vacuum performance will be maintained under the same condition for a time of about <NUM> 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, the 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 most preferably considered that, based on the vacuum maintenance performance, the PPS is used as the material of the supporting unit.

<FIG> illustrates 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> illustrates a result obtained by analyzing a gas discharged from the low outgassing PC. In <FIG>, it may be seen that H<NUM> series (I), H<NUM>O series (II), N<NUM>/CO/CO<NUM>/O<NUM> series (III), and hydrocarbon series (IV) are equally discharged. <FIG> illustrates a result obtained by analyzing a gas discharged from the PPS. In <FIG>, it may be seen that H<NUM> series (I), H<NUM>O series (II), and N<NUM>/CO/CO<NUM>/O<NUM> series (III) are discharged to a weak extent. <FIG> is a result obtained by analyzing a gas discharged from stainless steel. In <FIG>, 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> illustrates results obtained by measuring maximum deformation temperatures at which resins are damaged by atmospheric pressure in high-temperature exhaustion. At this time, the bars <NUM> were provided at a diameter of <NUM> at a distance of <NUM>. Referring to <FIG>, it may be seen that a rupture occurs at <NUM> in the case of the PE, a rupture occurs at <NUM> in the case of the low outgassing PC, and a rupture occurs at <NUM> in the case of the PPS.

As the analyzed result, it may be seen that the PPS is most preferably used as the resin used inside the vacuum space part. However, the low outgassing PC may be used in terms of fabrication cost.

A radiation resistance sheet <NUM> for reducing heat radiation between the first and second plate members <NUM> and <NUM> through the vacuum space part <NUM> will be described. The first and second plate members <NUM> and <NUM> may be made of a stainless material capable of preventing corrosion and providing a sufficient strength. The stainless material has a relatively high emissivity of <NUM>, and hence a large amount of radiation heat may be transferred. In addition, the supporting unit <NUM> made 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 members <NUM> and <NUM>. Hence, the supporting unit <NUM> does not have great influence on radiation heat. Therefore, the radiation resistance sheet <NUM> may be provided in a plate shape over a majority of the area of the vacuum space part <NUM> so as to concentrate on reduction of radiation heat transferred between the first and second plate members <NUM> and <NUM>. A product having a low emissivity may be preferably used as the material of the radiation resistance sheet <NUM>. In an embodiment, an aluminum foil having an emissivity of <NUM> may be used as the radiation resistance sheet <NUM>. Also, since the transfer of radiation heat may not be sufficiently blocked using one radiation resistance sheet, at least two radiation resistance sheets <NUM> may 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 member <NUM> or <NUM>.

Referring back to <FIG>, the distance between the plate members is maintained by the supporting unit <NUM>, and a porous material <NUM> may be filled in the vacuum space part <NUM>. The porous material <NUM> may have a higher emissivity than the stainless material of the first and second plate members <NUM> and <NUM>. However, since the porous material <NUM> is filled in the vacuum space part <NUM>, the porous material <NUM> has a high efficiency for resisting the radiation heat transfer.

In the present example, not forming part of this invention, the vacuum adiabatic body may be manufactured without the radiation resistance sheet <NUM>.

<FIG> is a view showing various embodiments of conductive resistance sheets and peripheral parts thereof. Structures of the conductive resistance sheets are briefly illustrated in <FIG>, but will be understood in detail with reference to the drawings.

First, a conductive resistance sheet proposed in <FIG> may be preferably applied to the main body-side vacuum adiabatic body. Specifically, the first and second plate members <NUM> and <NUM> are to be sealed so as to vacuumize the interior of the vacuum adiabatic body. In this case, since the two plate members have different temperatures from each other, heat transfer may occur between the two plate members. A conductive resistance sheet <NUM> is provided to prevent heat conduction between two different kinds of plate members.

The conductive resistance sheet <NUM> may be provided with sealing parts <NUM> at which both ends of the conductive resistance sheet <NUM> are sealed to defining at least one portion of the wall for the third space and maintain the vacuum state. The conductive resistance sheet <NUM> may 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 parts <NUM> may be provided as welding parts. That is, the conductive resistance sheet <NUM> and the plate members <NUM> and <NUM> may be fused to each other. In order to cause a fusing action between the conductive resistance sheet <NUM> and the plate members <NUM> and <NUM>, the conductive resistance sheet <NUM> and the plate members <NUM> and <NUM> may be made of the same material, and a stainless material may be used as the material. The sealing parts <NUM> are not limited to the welding parts, and may be provided through a process such as cocking. The conductive resistance sheet <NUM> may be provided in a curved shape. Thus, a heat conduction distance of the conductive resistance sheet <NUM> is provided longer than the 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 sheet <NUM>. Therefore, in order to block heat transfer to the exterior of the conductive resistance sheet <NUM>, a shielding part <NUM> may be provided at the exterior of the conductive resistance sheet <NUM> such that an adiabatic action occurs. In other words, in the refrigerator, the second plate member <NUM> has a high temperature and the first plate member <NUM> has a low temperature. In addition, heat conduction from high temperature to low temperature occurs in the conductive resistance sheet <NUM>, and hence the temperature of the conductive resistance sheet <NUM> is suddenly changed. Therefore, when the conductive resistance sheet <NUM> is opened to the exterior thereof, heat transfer through the opened place may seriously occur. In order to reduce heat loss, the shielding part <NUM> is provided at the exterior of the conductive resistance sheet <NUM>. For example, when the conductive resistance sheet <NUM> is exposed to any one of the low-temperature space and the high-temperature space, the conductive resistance sheet <NUM> does not serve as a conductive resistor as well as the exposed portion thereof, which is not preferable.

The shielding part <NUM> may be provided as a porous material contacting an outer surface of the conductive resistance sheet <NUM>. The shielding part <NUM> may be provided as an adiabatic structure, e.g., a separate gasket, which is placed at the exterior of the conductive resistance sheet <NUM>. The shielding part <NUM> may be provided as a portion of the vacuum adiabatic body, which is provided at a position facing a corresponding conductive resistance sheet <NUM> when 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 part <NUM> may be preferably provided as a porous material or a separate adiabatic structure.

A conductive resistance sheet proposed in <FIG> may be preferably applied to the door-side vacuum adiabatic body. In <FIG>, portions different from those of <FIG> are described in detail, and the same description is applied to portions identical to those of <FIG>. A side frame <NUM> is further provided at an outside of the conductive resistance sheet <NUM>. 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, and the like may be placed on the side frame <NUM>. This is because the mounting of parts is convenient in the main body-side vacuum adiabatic body, but the 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 sheet <NUM> at a front end portion of the vacuum space part, i.e., a corner side portion of the vacuum space part. This is because, unlike the main body, a corner edge portion of the door is exposed to the exterior. More specifically, if the conductive resistance sheet <NUM> is 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 sheet <NUM>.

A conductive resistance sheet proposed in <FIG> may be preferably installed in the pipeline passing through the vacuum space part. In <FIG>, portions different from those of <FIG> are described in detail, and the same description is applied to portions identical to those of <FIG>. A conductive resistance sheet having the same shape as that of <FIG>, preferably, a wrinkled conductive resistance sheet <NUM> may be provided at a peripheral portion of the pipeline <NUM>. 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 the adiabatic performance of the conductive resistance sheet.

A heat transfer path between the first and second plate members <NUM> and <NUM> will be described with reference back to <FIG>. Heat passing through the vacuum adiabatic body may be divided into surface conduction heat ① conducted along a surface of the vacuum adiabatic body, more specifically, the conductive resistance sheet <NUM>, supporter conduction heat ② conducted along the supporting unit <NUM> provided inside the vacuum adiabatic body, gas conduction heat ③ conducted through an internal gas in the vacuum space part, and radiation transfer heat ④ 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 members <NUM> and <NUM> may endure a vacuum pressure without being deformed, the vacuum pressure may be changed, the distance between the plate members may be changed, and the 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 preferred 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 <NUM> 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 ③ may become smallest. For example, the heat transfer amount by the gas conduction heat ③ may be controlled to be equal to or smaller than <NUM>% of the total heat transfer amount. A heat transfer amount by solid conduction heat defined as a sum of the surface conduction heat ① and the supporter conduction heat ② is largest. For example, the heat transfer amount by the solid conduction heat may reach <NUM>% of the total heat transfer amount. A heat transfer amount by the radiation transfer heat ③ is transfer 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 ③ may occupy about <NUM>% 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 ①, the supporter conduction heat ②, the gas conduction heat ③, and the radiation transfer heat ④ transfer may have an order of Math Equation <NUM>.

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 (m<NUM>) 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 sheet <NUM> or <NUM>, 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 unit <NUM>, 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 ③, and the radiation transfer heat ④ 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 ③, and the radiation transfer heat ④ may be obtained by evaluating radiation transfer heat when no gas conduction heat exists by remarkably lowering a vacuum degree of the vacuum space part <NUM>.

When a porous material is provided inside the vacuum space part <NUM>, porous material conduction heat ⑤ may be a sum of the supporter conduction heat ② and the radiation transfer heat ④. The porous material conduction heat may be changed depending on various variables including a kind, an amount, and the like of the porous material.

According to an embodiment, a temperature difference ΔT<NUM> between a geometric center formed by adjacent bars <NUM> and a point at which each of the bars <NUM> is located may be preferably provided to be less than <NUM>. Also, a temperature difference ΔT<NUM> between the geometric center formed by the adjacent bars <NUM> and an edge portion of the vacuum adiabatic body may be preferably provided to be less than <NUM>. In the second plate member <NUM>, 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 sheet <NUM> or <NUM> meets 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/m<NUM>) of a certain level may be preferably used.

Under such circumferences, the plate members <NUM> and <NUM> and the side frame <NUM> may be preferably made of a material having a sufficient strength with which they are not damaged by even vacuum pressure. For example, when the number of bars <NUM> is decreased so as to limit the support conduction heat, deformation of the plate member occurs due to the vacuum pressure, which may bad influence on the external appearance of refrigerator. The radiation resistance sheet <NUM> may be preferably made of a material that has a low emissivity and may be easily subjected to thin film processing. Also, the radiation resistance sheet <NUM> is to ensure a strength enough not to be deformed by an external impact. The supporting unit <NUM> is provided with a strength enough to support the force by the vacuum pressure and endure an external impact, and is to have machinability. The conductive resistance sheet <NUM> may be preferably 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 sheets <NUM> or <NUM> may be made of a material having a strength, but the stiffness of the material is preferably 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 sheet <NUM> requires a stiffness of a certain level so as not to contact another part due to deformation. Particularly, an edge portion of the radiation resistance sheet may generate conduction heat due to drooping caused by the self-load of the radiation resistance sheet. Therefore, a stiffness of a certain level is required. The supporting unit <NUM> requires 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 preferably have the highest stiffness so as to prevent deformation caused by the vacuum pressure. The supporting unit, particularly, the bar may preferably have the second highest stiffness. The radiation resistance sheet may preferably 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 preferably made of a material that is easily deformed by the vacuum pressure and has the lowest stiffness.

Even when the porous material <NUM> is filled in the vacuum space part <NUM>, the conductive resistance sheet may preferably have the lowest stiffness, and the plate member and the side frame may preferably have the highest stiffness.

As described above, various resin materials may be applied to the supporting unit <NUM>. Particularly, a PPS may be preferably used. However, a resin containing a large amount of PPS may have an advantage in that outgassing is low, but have a limitation in that moldability is poor due to high viscosity in a liquid state. In this case, since the molded supporting unit is changed in shape when designed, damage and shape change may occur when parts are coupled to each other.

Hereinafter, various specific examples of the supporting unit, which are capable of solving the above limitations, are proposed.

<FIG> is a schematic perspective view of a supporting unit according to any embodiment.

Referring to <FIG>, a supporting unit <NUM> includes a non-lattice support <NUM> manufactured in a planar shape, i.e., a two-dimensional planar structure and a left bar <NUM> and a right bar <NUM>, which respectively protrude from left and right surfaces of the non-lattice support <NUM>. The left bar <NUM> and the right bar <NUM> may have the same length. Thus, it is understood that the non-lattice support <NUM> is disposed between the left bar and the right bar.

Thus, an injection liquid introduced into any point of a molding frame may widely flow through an inner empty space of the non-lattice support <NUM>. In addition, since each of the left bar <NUM> and the right bar <NUM> has a length less than a half of a width of the inner space of the vacuum adiabatic body, the injection liquid may smoothly flow in the molding frame constituting the left bar <NUM> and the right bar <NUM>. In case of the bar <NUM> has a length equal to the width of the inner space of the vacuum adiabatic body, it may be easily understood by comparison with the case in which the injection liquid does not reach an end of the bar <NUM>, and a desired shape of the bar <NUM> may not be obtained when the flow distance of the injection liquid becomes long. If the width of the vacuum adiabatic body is maintained in small enough, the non-lattice support <NUM> need not be provided in the middle of the vacuum adiabatic body. However, it is most preferable for the shape of the bar to be provided in a desired shape.

For the flow of the injection liquid, it is preferable that the width of the bar decreases toward the end.

The non-lattice support <NUM> may be molded together with the left bar <NUM> and the right bar <NUM>.

It is preferable that the non-lattice support <NUM> is a two-dimensional plane and has no vacant area. A coating surface <NUM> may be provided on at least one outer surface of two outer surfaces of the non-lattice support <NUM>. A metal material having low emissivity may be applied to the coating surface to perform a function of the radiation resistance sheet. Aluminum may be used as the metal material.

The coating surface <NUM> may be performed as one process when the non-lattice support <NUM> is mass-produced. Thus, the function of the radiation resistance sheet <NUM> may be realized through only a simple process.

According to the present embodiment, there is an advantage that it is not necessary to provide a separate structure for manufacturing the radiation resistance sheet, fixing the radiation resistance sheet, providing a separator structure for installing the radiation resistance sheet, and installing the radiation resistance sheet when the vacuum adiabatic body is manufactured.

The non-lattice support <NUM> is a part having a predetermined thickness. Thus, more expensive resin material such as PPS is introduced, and outgassing further increases. Another embodiment is proposed in consideration of this limitation.

According to the present embodiment, in providing the supporting unit <NUM>, it is possible to eliminate the inconvenience that the bars <NUM> extending from the pair of facing support plates <NUM> are engaged with each other. That is to say, in order to provide an female structure and a male structure at the ends of the facing bars <NUM> and to be coupled to each other, numerous aligning structures and insertion of the aligned structures are required. On the other hand, since the left bar <NUM> and the right bar <NUM> are manufactured on both sides of the support, there is no need to separately align or couple the bars.

When the left bar <NUM> and the right bar <NUM> contact the plate members <NUM> and <NUM>, an unevenness may occur on the plate member. Thus, to reduce the unevenness, a planarization plate may be provided. A detailed configuration of the planarization plate will be described later.

These advantages may be similarly implemented in all of the following embodiments.

<FIG> is a perspective view of a supporting unit according to another embodiment.

Referring to <FIG>, a supporting unit <NUM> includes a lattice support <NUM> manufactured in a two-dimensional lattice structure and a left bar <NUM> and a right bar <NUM>, which respectively protrude to left and right sides of the non-lattice support <NUM>. The left bar <NUM> and the right bar <NUM> may be provided at the intersection of the lattices for reinforcement of strength.

The left bar and the right bar may function as the supporting unit <NUM> by directly or indirectly contacting the plate members <NUM> and <NUM>.

The radiation resistance sheet <NUM> may be supported by the lattice support <NUM>. The radiation resistance sheet <NUM> may be supported by the lattice support <NUM>, and both left and right sides of the radiation resistance sheet <NUM> face the plate members <NUM> and <NUM> to resist to radiation heat transfer.

A center of each lattice of the lattice support <NUM> is empty, and no resin is used. Therefore, an amount of resin used may be reduced, and outgassing may be reduced.

The radiation resistance sheet <NUM> may be supported by the lattice support <NUM> through various methods. <FIG> illustrates a coupling manner, and <FIG> illustrates an insert injection manner.

First, referring to <FIG>, a left lattice support <NUM> and a right lattice support <NUM> are disposed to be symmetrical to each other, and the radiation resistance sheet <NUM> is inserted between the left and right lattice supports <NUM> and <NUM>.

Thereafter, the left lattice support <NUM> and the right lattice support <NUM> are coupled to each other. The radiation resistance sheet <NUM> are fixed between the left lattice support <NUM> and the right lattice support <NUM>. The coupling between the left lattice support <NUM> and the right lattice support <NUM> may be realized by fusing portions of the two parts or coupling the two parts by using a fixing tool.

Referring to <FIG>, in a state in which the radiation resistance sheet <NUM> is inserted into the molding frame, an injection liquid is injected into the molding frame. The radiation resistance sheet <NUM> forms a body with the lattice support <NUM> as the injection liquid in the molding frame is cured.

According to the present embodiment, the radiation resistance sheets may be conveniently handled in batches at the manufacturing stage of the parts. In addition, an amount of resin to be used may be reduced.

The method of coupling the radiation resistance sheet <NUM> to the non-lattice support may be variously proposed.

<FIG> is a view illustrating an example in which the radiation resistance sheet is fixed to the left bar and/or the right bar according to an embodiment.

Referring to <FIG>, the radiation resistance sheet <NUM> may be inserted to be fixed to the left bar <NUM> and the right bar <NUM>. A hole may be previously processed in the radiation resistance sheet <NUM>, and the bar may be inserted into the hole.

When the left bar <NUM> and the right bar <NUM> are inserted into the hole, a support protrusion <NUM> may be provided on each of the left bar <NUM> and the right bar <NUM> to prevent the radiation resistance sheet from being separated due to oscillation even if vibration or impact occurs. To secure fluidity of the injection liquid, each of the left bar <NUM> and the right bar <NUM> may be provided with a thinner section toward the end thereof. Thus, the radiation resistance sheet <NUM> may be prevented from being pulled out by being caught by the support protrusion <NUM> after radiation resistance sheet <NUM> passes over the support protrusion <NUM>.

In the present embodiment, the radiation resistance sheet may be deformed or damaged while the radiation resistance sheet is forcibly inserted into the bar. Thus, there is a limitation that the operator has to pay more attention. A method for solving this limitation is proposed in <FIG>.

<FIG> is a plan view illustrating an example in which the radiation resistance sheet is fixed to the bar according to another embodiment.

First, referring to <FIG>, holes <NUM> each of which has a predetermined shape and into which the bar is inserted are defined in the radiation resistance sheet <NUM>. The holes <NUM> are symmetrical to each other in a plurality of directions.

A round support piece <NUM> smoothly protruding to contact the left bar <NUM> and the right bar <NUM> and a groove <NUM> allowing the round support piece <NUM> to be smoothly bent are provided in an edge of the hole <NUM>.

An end of the round support piece <NUM> has a rounded shape. According to this shape, when the bar is inserted into the hole of the radiation, damage of the bar may be prevented. The round support piece <NUM> may be more smoothly deformed by the groove <NUM>.

The lattice support <NUM> and the bar <NUM> are observed inside the hole <NUM>.

Referring to <FIG>, holes <NUM> each of which has a predetermined shape and into which the bar is inserted are defined in the radiation resistance sheet <NUM>. The holes <NUM> are symmetrical to each other in a plurality of directions.

A wide support piece <NUM> including a linear holding part <NUM> and having a wide contact length on each of the left bar <NUM> and the right bar <NUM> is provided on the edge of the hole <NUM>. The linear holding part <NUM> may have an arc shape similar to an outer appearance of each of the bars <NUM> and <NUM>. Thus, the bar may be supported at a wide interval to stably support the inserted radiation resistance sheet <NUM> without being separated. A groove <NUM> allowing the wide support piece <NUM> to be smoothly bent may be provided.

Referring to <FIG>, although the holes are symmetrical to each other in a plurality of directions like the above-described holes, a thick cross-shaped hole <NUM> having a thick cross shape is provided.

When the bars <NUM> and <NUM> are inserted into the thick cross-shaped hole <NUM>, a cusp <NUM> may spear and hold the bar. Thus, the fixed position of the radiation resistance sheet may be more stably maintained.

A small cross-shaped hole <NUM> having a shape corresponding to the thick cross-shaped hole <NUM> may be provided in <FIG>.

When comparing the thick cross-shaped hole <NUM> with the small cross-shaped hole <NUM>, it is the same that the cusp <NUM> is provided. However, an area on which a contact piece <NUM> contacts the bar may be smaller in the thick cross-shaped hole <NUM>.

As described above, as the contact area of the contact piece is reduced, the heat transfer between the radiation resistance sheet and the bar may be further reduced.

As illustrated in <FIG> and <FIG>, the radiation resistance sheet <NUM> may be fixed in a manner directly mounted on the bar <NUM>. The support protrusion <NUM> and the piece-shaped members <NUM>, <NUM>, and <NUM> may be applied to each other in a redundant manner.

The position of the radiation resistance sheet <NUM> may be directly fixed to the interval between the supports <NUM> and <NUM> and the plate members <NUM> and <NUM>. Hereinafter, details will be described with reference to the accompanying drawings.

<FIG> and <FIG> are views for explaining the self-standing type radiation resistance sheet.

Referring to <FIG>, the self-standing type radiation resistance sheet may be provided in a spacing part between the lattice support <NUM> and the plate members <NUM> and <NUM>.

To allow the self-standing type radiation resistance sheet <NUM> to stand up in itself, the self-standing type radiation resistance sheet <NUM> includes a sheet base <NUM> having a two-dimensional wide plate shape and a sheet protrusion <NUM> protruding from the sheet base <NUM>. The sheet protrusion <NUM> may be provided on the plate-shaped sheet through press processing. The sheet protrusion <NUM> and the sheet base <NUM> may be integrally provided.

The sheet base <NUM> may contact the lattice support <NUM>, and the sheet protrusion <NUM> may contact any member toward the plate member <NUM> and thus be supported in its position. To prevent the self-standing type radiation resistance sheet <NUM> from moving along the lattice support <NUM>, a through-hole <NUM>, through which the bars <NUM> and <NUM> pass, may be further provided.

The self-standing type radiation resistance sheet <NUM> may be provided on all left and right sides of the lattice support <NUM> to improve an effect of radiation resistance.

The self-standing type radiation resistance sheet <NUM> may be made of a metal material and thus be high in thermal conductivity. When the self-standing type radiation resistance sheet <NUM> directly contacts the plate members <NUM> and <NUM>, heat loss may increase. To solve this limitation, a heat conduction prevention tool <NUM> may be further provided at a portion at which the self-standing type radiation resistance sheet <NUM> contacts the plate members <NUM> and <NUM>.

Referring to <FIG>, like <FIG>, it is seen that the self-standing type radiation resistance sheet <NUM> is disposed on only any one side of the lattice support <NUM>. It is seen that the bar <NUM> is inserted into the through-hole <NUM> to prevent the self-standing type radiation resistance sheet <NUM> from moving in a vertical direction or a vertical direction with respect to the ground in the drawings.

It is seen that the bars <NUM> and <NUM> protrude outward in all of the lattice support <NUM> and the non-lattice support <NUM>. Each of the bars <NUM> and <NUM> is a small part made of a resin material. Thus, the bars <NUM> and <NUM> may be easily damaged during storage and transport. When the bars <NUM> and <NUM> are mounted on the vacuum adiabatic body, the bars <NUM> and <NUM> may be deformed due to collision with other parts.

An insertion guide may be coupled to the outside of each of the bars <NUM> and <NUM> in consideration of this limitation. The insertion guide may prevent the bars <NUM> and <NUM> from being deformed and damaged when the supporting unit <NUM> is inserted between the plate members <NUM> and <NUM>. The insertion guide may protect the bar during the storage and the transport.

<FIG> is a view for explaining the insertion guide.

Referring to <FIG>, the insertion guide <NUM> is fixed to the plurality of bars <NUM> and <NUM> extending to both sides of the supports <NUM> and <NUM>. As described above, the insertion guide <NUM> may prevent the bar from being damaged when the supporting unit is slidably inserted between the plate members and prevent the bar from being damaged during the storage and the transport.

In addition, when vacuum exhaust is performed in the state in which the supporting unit <NUM> is mounted, any one bar may be prevented from being locally damaged due to partial concentration of a load. That is to say, a generally uniform load may be applied by the insertion guide <NUM> to prevent the bar from buckling. The bars <NUM> and <NUM> may be seated in a groove corresponding to the insertion guide <NUM>. In this case, the buckling may be more reliably prevented.

The insertion guide <NUM> may be inserted into the spacing part between the plate members <NUM> and <NUM>. Here, to realize the smooth insertion, various surface treatment may be performed on an outer surface of the insertion guide <NUM>, i.e., a surface at which the insertion guide faces the plate members <NUM> and <NUM>.

<FIG> and <FIG> are views illustrating an example of the surface treatment.

Referring to <FIG>, the insertion guide <NUM> may have an unevenness <NUM> on the guide frame <NUM> and the outer surface of the guide frame <NUM>, i.e., surfaces facing the plate members <NUM> and <NUM>. The unevenness <NUM> may reduce friction force on an inner surface of each of the plate members <NUM> and <NUM> and the outer surface of the insertion guide <NUM> and allow the insertion guide <NUM> to be smoothly inserted by small deformation of the unevenness.

Referring to <FIG>, the insertion guide <NUM> may have a coating surface <NUM> on the outer surface of the guide frame <NUM>, i.e., a coating surface <NUM> facing the plate members <NUM> and <NUM>. The coating surface <NUM> may reduce friction force on an inner surface of each of the plate members <NUM> and <NUM> and the outer surface of the insertion guide <NUM> and allow the insertion guide <NUM> to be smoothly inserted. The coating surface may be Teflon coated.

A fitting groove into which the bar is fitted may be provided in the guide frame <NUM>. In a state in which at least several bars are fitted into the fitting groove, the transport and storage may be performed. Of course, all the bars may be fitted into the corresponding grooves or holes to prevent the bar from being damaged.

<FIG> is a cross-sectional view illustrating further another example of the insertion guide.

Referring to <FIG>, the insertion guide <NUM> may not be provided in a flat plate shape but be provided in a predetermined structure having a frame. That is to say, the fitting groove <NUM> may be provided in the guide frame <NUM> as a mesh structure having a lattice shape or a frame. A reinforcing structure may be provided at a portion, in which the fitting groove <NUM> is provided, in a manner in which the frame reinforces a thickness.

According to the guide frame <NUM> provided as the mesh structure, an amount of resin to be used may be reduced.

<FIG> is a view illustrating the fitting groove of the insertion guide.

Referring to <FIG>, a plurality of fitting grooves <NUM> may be provided in an edge of the insertion guide <NUM> so that the bars <NUM> and <NUM> are coupled.

Since the bar is coupled to the fitting groove <NUM>, the supporting unit may be provided as one body. A seat groove <NUM> for preventing the bar from buckling may be provided in the portion on which the bar is disposed. The seat groove <NUM> may not affect the coupling of the bar and the insertion guide, but it is possible to prevent the bar from twisted to prevent the bar from buckling. It is understood that a single seat groove <NUM> is provided as an example, but a plurality of seat grooves <NUM> are provided.

The bars <NUM> and <NUM> may directly contact the plate members <NUM> and <NUM> to support the interval between the plate members. However, when the bar directly contact the plate member, the plate member may be bent by force due to a high vacuum pressure. This phenomenon does not greatly affect the inside of the vacuum adiabatic body, but the bending that occurs on the outer surface of the vacuum adiabatic body may cause a user's dissatisfaction.

A planarization plate may be further provided in the supporting unit to prevent this phenomenon from occurring and to achieve planarization of the plate member.

<FIG> is a view for explaining the supporting unit in which the planarization plate is provided.

Referring to <FIG>, the planarization plate <NUM> is disposed on an outer surface of each of the supports <NUM> and <NUM>, i.e., the outside of the right bar <NUM>. The planarization plate <NUM> may be disposed in a spacing part between the right bar <NUM> and the second plate member <NUM>.

An operation of the planarization plate <NUM> will be described. When an end of the right bar <NUM> directly contacts the second plate member <NUM>, the second plate member <NUM> may be recessed inward to be deformed by using a portion between the right bar <NUM> and the adjacent different right bar <NUM> as a support point. This is done because large force is applied to the support point of the right bar <NUM>.

Due to this phenomenon, the deformation of the second plate member <NUM> may be reduced by allowing the mesh shape or plate shape of the planarization plate <NUM> to be supported by the force. The coupling between the planarization plate <NUM> and the bar may be provided in a manner similar to the insertion guide <NUM>.

However, unlike that the seat groove <NUM> and the fitting groove <NUM> are provided different from each other, ends of all the bars may uniformly contact the planarization plate <NUM>. According to the above-described constituents, the uniform force may be applied to all the bars to prevent the bars from being damaged due to the concentration of the force.

The planarization plate <NUM> and the bar <NUM> may uniformly contact each other. However, the bar <NUM> may not be coupled to the planarization plate <NUM> in a manner in which the bar <NUM> is inserted into the groove of the planarization plate <NUM>. That is to say, as the number of coupled portions increases, the coupling process may be troublesome and difficult. For this, the number of coupling grooves between the planarization plate <NUM> and the bar <NUM> may be minimized. For example, the coupling groove may be provided in only a portion of an edge of the planarization plate <NUM>, and the bar <NUM> may be coupled to only the coupling groove to conveniently perform the coupling therebetween and improve work convenience through temporary assembly.

The planarization plate may be similarly provided with respect to the first plate. However, the inside of the vacuum adiabatic body is not a part of great interest to the user, so there is no great need.

<FIG> is a view for explaining an example in which an outer cover is disposed outside the plate member according to an embodiment.

If there is a limitation such as a narrow internal width of the vacuum adiabatic body, a planarization plate may not be provided. In this case, the second plate member may be bent.

Referring to <FIG>, an outer cover <NUM> may be further provided on an outer surface of the second plate member. The outer cover may cover the bent portion to further provide an elegant surface to the user.

According to the outer cover, since a separate planarization plate does not need to be coupled to the bar at the portion on which the outer cover is disposed, the supporting unit may be conveniently manufactured.

Although the outer cover and the planarization plate may be used together, it is not necessary to provide the two covers together in the same planar area. Thus, the area on which the planarization plate is easily installed may not be provided with the outer cover, and the area on which the outer cover is easily provided may not be provided. The convenience of manufacturing the supporting unit may be further improved by using the planarization plate and the outer cover in place.

<FIG> is a view for explaining another function of the planarization plate.

Referring to <FIG>, an end of the sheet protrusion <NUM> of the self-standing type radiation resistance sheet <NUM> may contact the planarization plate <NUM>. In this case, the planarization plate <NUM> may further perform the function of the conduction prevention tool <NUM>. In this case, the planarization plate <NUM> may be made of a resin material.

Hereinafter, a vacuum pressure preferably determined depending on an internal state of the vacuum adiabatic body. As already described above, a vacuum pressure is to be maintained inside the vacuum adiabatic body so as to reduce heat transfer. At this time, it will be easily expected that the vacuum pressure is preferably maintained as low as possible so as to reduce the heat transfer.

The vacuum space part may resist to heat transfer by only the supporting unit <NUM>. Here, a porous material <NUM> may be filled with the supporting unit inside the vacuum space part <NUM> to resist to the heat transfer.

The case where only the supporting unit is applied will be described.

<FIG> illustrates graphs showing changes in adiabatic performance and changes in gas conductivity with respect to vacuum pressures by applying a simulation.

Referring to <FIG>, 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 (Graph <NUM>) or in the case where the main body and the door are joined together (Graph <NUM>) is decreased as compared with that in the case of the typical product formed by foaming polyurethane, thereby improving the adiabatic performance. However, it may be seen that the degree of improvement of the adiabatic performance is gradually lowered. Also, it may be seen that, as the vacuum pressure is decreased, the gas conductivity (Graph <NUM>) is decreased. However, it may be seen that, although the vacuum pressure is decreased, the ratio at which the adiabatic performance and the gas conductivity are improved is gradually lowered. Therefore, it is preferable that the vacuum pressure is decreased as low as possible. However, it takes 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> is 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 to <FIG>, in order to create the vacuum space part <NUM> to be in the vacuum state, a gas in the vacuum space part <NUM> is exhausted by a vacuum pump while evaporating a latent gas remaining in the parts of the vacuum space part <NUM> through 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 (ΔT<NUM>). After that, the getter is activated by disconnecting the vacuum space part <NUM> from the vacuum pump and applying heat to the vacuum space part <NUM> (ΔT<NUM>). If the getter is activated, the pressure in the vacuum space part <NUM> is 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 the activation of the getter is approximately <NUM>×<NUM>-<NUM> 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 the lowest limit of the vacuum pressure used in the vacuum adiabatic body, thereby setting the minimum internal pressure of the vacuum space part <NUM> to <NUM>×<NUM>-<NUM> Torr.

<FIG> is a graph obtained by comparing a vacuum pressure with gas conductivity.

Referring to <FIG>, gas conductivities with respect to vacuum pressures depending on sizes of a gap in the vacuum space part <NUM> are represented as graphs of effective heat transfer coefficients (eK). Effective heat transfer coefficients (eK) were measured when the gap in the vacuum space part <NUM> has three sizes of <NUM>, <NUM>, and <NUM>. The gap in the vacuum space part <NUM> is defined as follows. When the radiation resistance sheet <NUM> exists inside vacuum space part <NUM>, the gap is a distance between the radiation resistance sheet <NUM> and the plate member adjacent thereto. When the radiation resistance sheet <NUM> does not exist inside vacuum space part <NUM>, the gap is a distance between the first and second plate members.

It was seen that, since the size of the gap is small at a point corresponding to a typical effective heat transfer coefficient of <NUM> W/mK, which is provided to a adiabatic material formed by foaming polyurethane, the vacuum pressure is <NUM>×<NUM>-<NUM> Torr even when the size of the gap is <NUM>. Meanwhile, 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 <NUM>×<NUM>-<NUM> Torr. The vacuum pressure of <NUM>×<NUM>-<NUM> 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 <NUM> W/mK, the vacuum pressure is <NUM>×<NUM>-<NUM> Torr.

When the vacuum space part <NUM> is 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 <NUM>×<NUM>-<NUM> Torr. Also, the vacuum pressure at the point at which the reduction in adiabatic effect caused by gas conduction heat is saturated is approximately <NUM>×<NUM>-<NUM> Torr. Also, the pressure where the reduction in adiabatic effect caused by gas conduction heat reaches the typical effective heat transfer coefficient of <NUM> W/mK is <NUM> 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 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 the present disclosure, 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 the present disclosure may be preferably 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.

Claim 1:
A vacuum adiabatic body comprising:
a first plate member (<NUM>) defining at least a portion of a wall for a first space;
a second plate member (<NUM>) defining at least a portion of a wall for a second space having a temperature different from that of the first space;
a sealing part (<NUM>) sealing the first plate member (<NUM>) and the second plate member (<NUM>) to provide a third space (<NUM>) that has a temperature between a temperature of the first space and a temperature of the second space and is a vacuum space;
a supporting unit (<NUM>) maintaining the third space (<NUM>);
a heat resistance unit (<NUM>) reducing a heat transfer amount between the first plate member (<NUM>) and the second plate member (<NUM>), the heat resistance unit (<NUM>) comprising a radiation resistance sheet (<NUM>) disposed in the third space (<NUM>); and
an exhaust port (<NUM>) through which a gas of the third space (<NUM>) is exhausted,
wherein the supporting unit (<NUM>) comprises:
a support (<NUM>, <NUM>) having a two-dimensional planar structure and crossing the third space (<NUM>);
characterized in that the supporting unit (<NUM>) comprises a left bar (<NUM>) and a right bar (<NUM>), which respectively extend from both sides of the support (<NUM>, <NUM>) to the first and the second plate members (<NUM>, <NUM>); and
wherein the radiation resistance sheet (<NUM>) is supported by at least one of the left bar (<NUM>) and the right bar (<NUM>);
wherein the radiation resistance sheet (<NUM>) includes a hole (<NUM>) into which the bar (<NUM>, <NUM>) is inserted; and
wherein:
- a support piece (<NUM>) protruding to contact the left bar (<NUM>) or the right bar (<NUM>) and a groove (<NUM>) allowing the support piece (<NUM>) to be bent are provided in an edge of the hole (<NUM>); or
- a support piece (<NUM>) including a linear holding part (<NUM>) and having a contact length on the left bar (<NUM>) or the right bar (<NUM>) is provided on the edge of the hole (<NUM>), wherein the linear holding part (<NUM>) has an arc shape similar to an outer appearance of the bar (<NUM>, <NUM>) and a groove (<NUM>) allowing the support piece (<NUM>) to be bent is provided; or
- wherein the hole is a cross-shaped hole (<NUM>), and when the bar (<NUM>, <NUM>) is inserted into the cross-shaped hole (<NUM>), a cusp (<NUM>) spears and holds the bar (<NUM>, <NUM>).