WO2011147901A2

WO2011147901A2 - Refrigeration appliance and low-pressure storage unit therefor

Info

Publication number: WO2011147901A2
Application number: PCT/EP2011/058610
Authority: WO
Inventors: Yegui Huang; Jingdong Ma; Zhenyu Yang; Defei Zhao
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2010-05-28
Filing date: 2011-05-26
Publication date: 2011-12-01
Also published as: CN102261801A; CN102261801B; EP2577194A2; WO2011147901A3

Abstract

The present invention relates to a low-pressure storage unit for a refrigeration appliance and such a refrigeration appliance. The low-pressure storage unit (7) comprises an evacuable storing chamber (32). According to suggestion of the present invention, the storing chamber (32) has at least one wall (21, 23), which is made of metal and has a plurality of reinforcement structures (34a, 34b, 34c) that are spaced apart from one another.

Description

REFRIGERATION APPLIANCE AND LOW-PRESSURE STORAGE UNIT

THEREFOR FIELD OF THE INVENTION

The present invention relates to a refrigeration appliance and a low-pressure storage unit therefore.

BACKGROUND

A refrigeration appliance having an evacuable storing chamber is well-known in the prior art. After the storing chamber is evacuated, the air content in it is reduced such that the hyperoxidation of foods is weakened to prolong the storing period and quality of the foods.

In a refrigeration appliance disclosed by Chinese patent application CN 103243942A and having an evacuable storing chamber (a low-pressure chamber), a main body of the low-pressure chamber having a food access opening comprises an external contour, which is formed by resin in a box shape and forms the food access opening, and a plate-shaped member made of metal, which member extends along a plurality of wall faces (including the bottom face) of the external contour. In this way, because the external contour that is easy to deform is supported by the plate-shaped member made of metal, the deformation of the external contour under pressure is reduced, such that the air tightness at the access site between the external contour and the low-pressure chamber door is ensured. However, when the endured pressure difference is large, the external contour made of resin is easy to deform and thus the air tightness of the low-pressure chamber is reduced.

Furthermore, although a larger thickness can be adopted to prevent the wall of the storing chamber from deforming, the larger thickness reduces the thermal conductive effect between the exterior and the interior of the storing chamber, and in this case the cabinet molding process is more complex and the defect rate of finished articles is high.

SUMMARY OF THE INVENTION

It is an objective of the present invention to solve at least one of the above-mentioned problems, such that it is possible to provide a low-pressure storage unit having a better pressure enduring and thermal conductive capability and a refrigeration appliance having said low-pressure storage unit.

To this end, the present invention in one aspect relates to a low-pressure storage unit for a refrigeration appliance, wherein the low-pressure storage unit comprises an evacuable storing chamber, characterized in that the storing chamber has at least one wall, which is made of metal and has a plurality of reinforcement structures that are spaced apart from one another.

In this way, the wall made of metal may have a less deformation amount under the same pressure, such that the low-pressure storage unit can endure a larger pressure. By providing the plurality of reinforcement structures spaced apart from each other, the wall made of metal has a relatively less thickness in at least a part of the wall region. Therefore, this facilitates not only saving material, but also improving the thermal conduction of the low-pressure storage unit.

Other individual features or features which are combined with other features so as to be considered as belonging to the characteristic of the present invention will be described in the attached claims. According to a preferred embodiment of the present invention, the wall has a constant thickness but is rugged to form the reinforcement structures.

According to a preferred embodiment of the present invention, the reinforcement structures are formed by protrusions that protrude outwardly from the wall.

According to a preferred embodiment of the present invention, the reinforcement structures are formed by stamping. According to a preferred embodiment of the present invention, the plurality of reinforcement structures are of different shapes, and at least one of the reinforcement structures has an arcuate contour.

According to a preferred embodiment of the present invention, among the plurality of reinforcement structures, at least one reinforcement structure is at least partially surrounded by another one or more reinforcement structures.

According to a preferred embodiment of the present invention, the wall has the reinforcement structure at its central region.

According to a preferred embodiment of the present invention, the wall is formed by a first member, which is of a box-structure and is made of metal, and that the first member has an opening on at least one side thereof. According to a preferred embodiment of the present invention, the plurality of reinforcement structures include at least one first reinforcement structure provided along an edge of the opening.

According to a preferred embodiment of the present invention, the plurality of reinforcement structures include such a first reinforcement structure that is provided along an edge of the opening and extends from a first longitudinal central axis, which is perpendicular to the opening, of the wall toward opposite lateral sides by at least one fourth of a lateral width of the wall.

According to a preferred embodiment of the present invention, the first reinforcement structure has a length, which is at least over three fourth of the width of the wall.

According to a preferred embodiment of the present invention, the first reinforcement structure is provided symmetrically with respect to the first central axis, and that both ends of the first reinforcement structure are close to both sides of the wall respectively.

According to a preferred embodiment of the present invention, the first reinforcement structure is in the shape of an elongated strip, and that the first reinforcement structure is provided adjacent a door for selectively closing or opening the opening.

According to a preferred embodiment of the present invention, the plurality of reinforcement structures include a second reinforcement structure which is disposed in the central region of the wall, and that the second reinforcement structure extends from the first longitudinal central axis, which is perpendicular to the opening, of the wall toward opposite lateral sides by at least one eighth of the lateral width of the wall.

According to a preferred embodiment of the present invention, the second

reinforcement structure has a contour which is at least partially arcuate.

According to a preferred embodiment of the present invention, the second

reinforcement structure is generally oval, and that the length, in a direction parallel to the opening, of the second reinforcement structure is larger than the length, in a direction perpendicular to the opening, thereof. According to a preferred embodiment of the present invention, it is characterized in that the low-pressure storage unit further comprises a second member, which is connected to the first member along the opening and is made of plastic.

According to a preferred embodiment of the present invention, the evacuable storage room is of a flat structure, and that the wall comprises a top wall and/or a bottom wall of the storing chamber. According to a preferred embodiment of the present invention, the thickness of the wall is not more than 4 millimeters, for example is in a range of 2 ~ 2.5 millimeters.

The present invention in another aspect relates to a refrigeration appliance, comprising a storage compartment and a low-pressure storage unit, which is received in the storage compartment and is claimed as above.

The configuration of the present invention and other objectives and beneficial effects thereof will be well understood by description of preferred embodiment in accompany of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

As a part of the description and in order to provide further explanation of the present invent, the drawings illustrate preferred embodiments of the present invention, and together with the description are used to explain the principle of the present invention. In the drawings:

Figure 1 shows a schematic perspective view of a refrigeration appliance according to a preferred embodiment of the present invention, wherein a door of the refrigeration appliance is not shown;

Figure 2 shows a schematic assembly perspective view of a low-pressure storage unit according to a preferred embodiment of the present invention;

Figure 3 is a schematic perspective view showing that the low-pressure storage unit according to the preferred embodiment of the present invention is opened;

Figure 4 is a schematic exploded view showing a main body of the low-pressure storage unit according to the preferred embodiment of the present invention;

Figure 5 is a schematic partial cross-sectional view taken in a direction A-A in figure 2;

Figure 6 is a schematic cross sectional view of the main body according to a preferred embodiment of the present invention along a longitudinal plane where the first central axis X lies.

DETAILED DESCRIPTION OF THE INVENTION As shown in figure 1 , a refrigeration appliance 1 comprises a thermally insulated cabinet 2, the cabinet 2 comprising an outer shell 2a, an inner shell 2b and a thermal insulation layer (not shown) therebetween. The cabinet 2 defines a plurality of thermally insulated storage compartments 3, 4 and 5 to store items such as foods. In the present embodiment, these storage compartments are an upper refrigeration compartment 3, a lower freezing compartment 5 and a preservation compartment 4 which is located between the upper and lower compartments and is maintained at a temperature of slightly higher than zero Degree Celsius. These storage compartments 3, 4 and 5 can be closed by respective doors (not shown). It should be understood that the present invention is not limited by the specific arrangement of the storage compartments of the refrigeration appliance. The present invention can be applied for other types of refrigeration appliance, such as a refrigerator having refrigerating and freezing compartments arranged one above the other, a side-by-side combination refrigerator as well as a refrigerator having a drawer-typed door and/or a French door refrigerator or the like.

The refrigeration appliance 1 has a close-looped evaporative refrigeration system. The refrigeration system comprises at least a compressor (not shown), a condenser (not shown), a throttling device (not shown) and an evaporator (not shown). Since this kind of refrigeration system is well-known in the prior art, its detailed explanation is omitted here.

The refrigeration appliance 1 is provided with a low-pressure storage unit 7, having an evacuable storing chamber 32, and an evacuation device (not shown) for evacuating gas out of the storing chamber 32. The evacuation device can comprise a vacuum pump and a pipeline (not shown) connecting between the vacuum pump and the low-pressure storage unit 7. In the present embodiment, the low-pressure storage unit 7 is provided in the preservation compartment 4. The low-pressure storage unit 7 is located at a bottom of the preservation compartment 4, and is supported on a bottom wall of the preservation compartment 4. In the present embodiment, a preservation container 6 is provided above the low-pressure storage unit 7, which preservation container has a higher humidity and is adapted for storing foods such as vegetables. It should be understood that, in an alternative embodiment, the low-pressure storage unit 7 can be provided in other storage compartments, such as the refrigerating compartment 3 or a variable compartment whose temperature zone can be changed between a refrigerating temperature zone and a freezing temperature zone. Figurer 2 is a schematic assembly perspective view showing the low-pressure storage unit 7 according to a preferred embodiment of the present invention. Figure 3 is a schematic perspective view showing that the low-pressure storage unit 7 according to the preferred embodiment of the present invention is opened. As shown in figures 2 and 3, in this embodiment, the low-pressure storage unit 7 is generally in the form of a flat rectangular parallelepiped and comprises a main body 8 being opened at one end and a drawer-typed container 9 which is movably received in the main body 8. The main body 8 defines a flat receiving space having a front opening. The drawer-typed container 9, at its front wall, is formed with a door 10 for closing the front opening of the main body 8. A tray-shaped container body 12 is connected at a rear side of the door 10 for storing items. The main body 8 is received and secured in the cabinet 2. It is preferable that the main body 8 is detachably secured in the

preservation compartment 4. A user can draw out the draw-typed container 9 to have access to the items in the low-pressure storage unit 7.

The main body 8 and the door 10 have widths which each are slightly less than the width of the preservation compartment 4. Thus it is ensured that the main body 8 and the door 10 can be inserted into the preservation compartment 4 or be pulled out of the preservation compartment 4. Therefore, gaps can be formed between both sides of the low-pressure storage unit 7 and the inner shell 2b of the preservation compartment 4 respectively. In order to shield these gaps, the low-pressure storage unit 7 can comprise a deformable gap shielding member 50 which is provided at the front end of the main body 8.

The low-pressure storage unit 7 has a housing 40 which is constituted by the main body 8 and the door 10 of the drawer-typed container 9. The housing 40 defines the evacuable storing chamber 32, wherein the tray-shaped container body 12 is located in the storing chamber 32. In the present embodiment, the storing chamber 32 is essentially formed by the receiving space of the main body 8.

When the storing chamber 32 is closed by the door 10 and the evacuation device is switched on, gas in the storing chamber 32 is evacuated off and the storing chamber 32 is in a low-pressure state. According to a preferred embodiment of the present invention, after the evacuation procedure is completed, the storing chamber 32 has a pressure therein, which pressure is between one standard atmospheric pressure and the absolute vacuum (for example, the absolute vacuum being less than 690 millibars). Because the gas pressure in the storing chamber 32 is less than one standard atmospheric pressure, this chamber can also be called as "a vacuum chamber" by the skilled in the art. In the present embodiment, the storing chamber 32 has a volume of about 20 L. A sealing element (not shown) can be provided at the front end of the main body 8 and/or at the door 10, such that there is a gas tightness engagement formed between the main body 8 and the door 10 after the drawer-typed container 9 is completely closed. Therefore, gas is prevented from entering into the storing chamber 32 via the engagement site between the main body 8 and the door 10.

A telescopic guide unit 14 is provided between the drawer-typed container 9 and the main body 8, such that the drawer-typed container 9 can be smoothly pulled out of the main body 8 or pushed into the main body 8. The door 10 is provide with a gas filling passage (not shown), which gas filling passage fluidly communicates with the interior and exterior of the storing chamber 32, and a gas filling valve (not shown) for opening or closing the gas filling passage. When the gas filling passage is opened by the gas filling valve, gas from the exterior can enter into the storing chamber 32 via the gas filling passage such that the low-pressure state of the storing chamber 32 is released.

The door 10 is provided with a handle 13 at its front end. The user can operate the drawer-typed container 9 by the handler 13. In a preferred embodiment, the gas filling valve is provided in such a way that it is associated with the handle 13. That is, when the handle 13 is operated, the gas filling valve is opened such that the storing chamber 32 fluidly communicates with the exterior. Therefore, gas can enter into the storing chamber 32 such that the low-pressure state of the storing chamber 32 is released. In an alternative embodiment, the gas filling valve can be provided independently from the handle 13. For example, the door 10 is provided with a button thereon. The gas filling valve is opened by pressing the button. Then, the user can operate the handle 13 to open the door 10.

The door 10, constituting the front wall of the storing chamber 32, is made of plastic which is easy to be molded, because some complex structures such as the gas filling valve and the handler 13 and so on will be formed. In the present embodiment, the door 10 is made of ABS resin (acrylonitrile butadiene styrene).

The inner surface of the door 10 is exposed to the storing chamber 32, and the outer surface of the door constitutes a part of the external contour of the low-pressure storage unit 7 so as to form a part of the wall of the storing chamber 32. When the storing chamber 32 is in the low-pressure state, the door 10 must endure a pressure difference between the interior and the exterior. However, the tray-shaped container body 12 endures no pressure because it is located in the storing chamber 32.

Therefore, the door 10 has a thickness which is larger than the tray-shaped container body 12. In the present embodiment, the thickness of the door 10 is 6 millimeters, and the tray-shaped container body 12 can have a thickness of about 1 to 2 millimeters.

Figure 4 is a schematic exploded perspective view showing the main body 8 according to a preferred embodiment of the present invention. As shown in figures 2 and 3 by combination with figure 4, the main body 8 comprises a box-shaped box body 11 which is opened at front and rear ends, a rear cover 16 which is secured at the rear end of the box body 11 to close a rear opening 26 of the box body 11 , and a front jointing unit 17, which is secured at an edge of a front opening 25 of the box body 11 .

A sealing element 18 is provided between the box body 11 and the rear cover 16 as well as between the box body 11 and the front jointing unit 17 respectively, such that the box body 11 forms a gas tightness engagement with the rear cover 16 and a gas tightness engagement with the front jointing unit 17 respectively.

In the present embodiment, the box body 11 comprises a top wall 21 , a bottom wall 23, left and right side walls 22 which are connected between the top wall 21 and the bottom wall 32. The top, bottom, left and right side walls are made of metal having a larger material strength. The box body 11 constitutes a main part of the housing 40. In the present embodiment, the top wall 21 , the bottom wall 23 and the left and right side walls 22, all of which are made of metal, are exposed at their inner sides to the storing chamber 32 respectively. Outer surfaces of these walls constitute a part of the external contour of the low-pressure storage unit 7. When the storing chamber 32 is in the low-pressure state, the top wall 21 , the bottom wall 23 and the left and right side walls 22 endure a pressure caused by the pressure in the storing chamber 32 being less than the pressure of the exterior.

The top wall 21 , the bottom wall 23 as well as the left and right side walls 22 can be produced by a metal sheet, whose thickness is not more than 4 millimeters. Preferably, the thicknesses of these walls 21 -23 are 2 millimeters to 2.5 millimeters.

The top wall 21 , the bottom wall 23 as well as the left and right side walls 22 of the box body 11 are preferably formed in a one-piece structure, such that any jointing seam between these walls can be reduced or even eliminated. In the present embodiment, the top wall 21 , the bottom wall 23 as well as the left and right side walls 22 are formed by a piece of metal sheet (cold rolled plate), which is bent into a rectangular shape and then is welded. As shown in figures 3 and 4, a welding seam 33 is located at the middle site of the right side wall 22. On the one hand, because the side wall 22 endures a less pressure than the top wall 21 and the bottom wall 23, this may facilitate reducing a possibility that air leakage occurs at the welding seam 33 under pressure. On the other hand, this may also facilitate arranging a clamp during the welding procedure.

Furthermore, because the welding seam is located at a side wall which cannot be readily noticed by the user, this may facilitate achieving a better aesthetic of the refrigeration appliance 1 .

It should be understood that, in an alternative embodiment, it is also possible that the top wall 21 , the bottom wall 23 as well as the left and right side walls 22 of the box body 11 are formed by a plurality of metal sheets, which are jointed (such as welded) together.

Furthermore, the box body 11 can also be made of other metal such as aluminum. On the case that the box body is made of aluminum, the box body is preferably achieved by an integrally extruding procedure. Because the modulus of elasticity of aluminum is less than that of steel, it is preferable that the box body made of aluminum has a thickness of lager than 2 millimeters, for example being 4 millimeters.

In the present embodiment, the top wall 21 is symmetrical to the bottom wall 23. The two walls constitute a majority of the total wall area of the box body 11 .

According to a preferred embodiment of the present invention, as shown in figures 3, 4 and 5, mounting plates 27 are provided at the front and rear ends of the box body 11 and at outer sides of the top wall 21 , the bottom wall 23 as well as the left and right side walls 22, such that no through hole needs be provided on the top wall 21 , the bottom wall 23 as well as the left and right side walls 22 to secure the front jointing unit 17 and the rear cover 6 to the box body 11 . The mounting plates 27 can be made of metal, for example made by steel sheets.

Each mounting plate 27 comprises a jointing foot 27a, which is horizontally secured on a corresponding one of the walls 21 to 23. In the present embodiment, the mounting plate 27 is secured on the box body 11 by welding the jointing foot 27a to the corresponding one of the walls 21 to 23. In an alternative embodiment, the mounting plate 27 can be secured on the box body 11 in other ways, for example is adhered on the box body 11 .

The mounting plate 27 comprises an extension 27b, which folds from the jointing foot 27a and then extends outwardly. In the present embodiment, the extension 27b is substantially perpendicular to the corresponding one of the walls 21 to 23. The extension 27b has a plate shape. It has planar front and rear surfaces. The extensions 27b at the front and rear ends of the box body 11 each are at a distance from the front and rear end faces of the box body 11 . In the present embodiment, the mounting plate 27 has an L-shape in its cross-section, which is formed by the extension 27b and the jointing foot 27a. However, in an alternative embodiment, the extension 27b can be formed integrally on the

corresponding one of the walls 21 to 23 such that the extension extends outwards directly from the corresponding one of the walls 21 to 23 of the box body 11 .

Each extension 27b is provided with a plurality of first holes 31 a which extend all the way through the front and rear surfaces of the extension. Preferably, the first holes 31 a of each extension 27b are arranged at a predetermined interval with each other, and they are arrayed in a row. The first holes 31 a located at the front and rear ends of the box body 11 each form a rectangular frame, whose size is larger than the front/rear opening 25, 26. The corresponding rectangular frame encloses the box body 11 therein. The first holes 31 a at the rear end of the box body 11 are threaded. However, the first holes 31 a at the front end of the box body 11 are not threaded.

The rear cover 16 and the front jointing unit 17 according to a preferred embodiment of the present invention are particularly explained in their structures in detail below.

The rear cover 16 is connected to the rear opening 26 of the box body 11 , constitutes the rear wall of the housing 40 and delimits the rear boundary of the storing chamber 32. The rear cover 16 is in the form of a square plate, which corresponds to the rear opening 26. The rear cover 16 has a size which is larger than that of the rear opening 26. The rear cover 16 extends beyond the rear opening 26. The rear cover 16 is provided with an evacuation passage (not shown) extending through the rear cover 16 and an evacuation valve unit 36 for selectively closing or opening the evacuation passage. In the present embodiment, the evacuation valve unit 36 extends above the top wall 21 , and has a jointing opening 39 above the top wall 21 . The low-pressure storage unit 7 connects with a pipeline secured on the cabinet 2 via the jointing opening 39, such that the low-pressure storage unit 7 can fluidly

communicate with the evacuation device.

The rear cover 16 comprises a main wall portion 20 constituting the most part of the rear cover and a rear jointing portion 19, which is provided around the main wall portion 20 and connects the rear cover 16 to the edge of the rear opening 26. The rear jointing portion 19 connects with the entire edge of the rear opening 26.

In the present embodiment, the rear jointing portion 19 and the main wall portion 20 are produced by integral injection molding of plastic, whose modulus of elasticity is less than metal. Preferably, the rear cover 16 is made of material having a larger material strength, such as polycarbonate (PC). The main wall portion 20 made of PC has a thickness of about 6 millimeters. In order to enhance the strength of the main wall portion 20, the main wall portion 20 is provided with a plurality of reinforcing ribs 35 on its rear surface.

It should be understood that, in an alternative embodiment, the rear jointing portion 19 and the main wall portion 20 can be provided independently with each other, and then they are airtightly secured to form the rear cover 16. This will be particularly beneficial in the case that the rear jointing portion 19 and the main wall portion 20 are made of different materials.

The front jointing unit 17 connects at the entire edge of the front opening 25, and has a square framed structure forming a close-loop. The front jointing unit 17 has an abutting face 37 for abutting with the door 10. In the present embodiment, the abutting face 37 is planar, and is in the same longitudinal plane. When the door 10 is closed, the sealing element on the door 10 is pressed between the abutting face 37 and the door 10 to make a sealing effect. In order that the front jointing unit 17 and the rear cover 16 are airtightly connected on the box body 11 respectively, the front jointing unit 17 and the rear cover 16 each are provided with a ring-shaped groove 30 at a side facing the box body 11 , which groove is used to receive a ring-shaped sealing element 18. The front and rear ends of the top wall 21 , the side walls 22 and the bottom wall 23 of the box body 11 each are inserted into the corresponding groove 30. The sealing element 18 is located between the groove 30 and the box body 11 .

Outside of the groove 30, the front jointing unit 17 and the rear cover 16 each are provided with a plurality of second holes 31 b. These second holes 31 b are provided on the outer surface portions of the front jointing unit 17 and the rear jointing unit 19 beyond the top wall 21 , the side walls 22 and the bottom wall 23, and are located outside of the storing chamber 32. The second holes 31 b on the front jointing portion 17 and the rear cover 16 form rectangular frames respectively, each of which rectangular frames has a size which is larger than the front/rear opening 25, 26.

In the present embodiment, the second holes 31 b on the front jointing unit 17 extend forwards from the rear side of the front jointing unit 17, do not extend through the front jointing unit 17 and thus form blind holes, which are threaded therein for attaching screws 29. The second holes 31 b on the rear cover 16 extend forwards from the rear side of the rear jointing portion 19 through the rear jointing portion 19 and form through holes to be inserted by corresponding screws 29.

The front jointing unit 17 is formed by integral injection molding of plastic. In the present embodiment, because the front jointing unit 17 is provided with the threaded holes for attaching the screws 29, the front jointing unit 17 is formed from a mixture of PC resin having a larger strength and ABS resin having a better toughness by injection molding, such that the strength and the toughness of the unit is balanced. The securing manner between the front jointing unit 17, the rear cover 16 and the box body 11 will be particularly explained below.

The front jointing unit 17 and the rear cover 16 are secured on the front and rear ends of the box body 11 by a plurality of securing units respectively.

In the present embodiment, each securing unit comprises the screw 29, the first hole 31 a provided on the mounting plate 27 of the box body 11 and the second hole 31 b provided on the front jointing unit 17/the rear cover 16. By inserting the screw 29 into the first hole 31 a and the second hole 31 b and then screwing the screw 29 with the threaded first hole 31 a or the threaded second hole 31 b, the front jointing unit 17/the rear cover 16 each can be reliably secured on the box body 11 . By use of the screw 29, the securing unit provides a pretension force between the front jointing unit 17 and the box body 11 as well as between the rear cover 16 and the box body 11 , such that the sealing elements 18 located between the front jointing unit 17/the rear cover 16 and the box body 11 can be pressed and thus the sealing effect between the front jointing unit 17/the rear cover 16 and the box body 11 can be enhanced.

In an alternative embodiment, the securing unit can adopt another securing piece which can provide the pretension force. For example, the screw can be replaced by a rod-shaped piece which is integrally injection molded on the front jointing unit 17 and the rear cover 16. In this case, the second holes 31 b on the jointing frame 17 and the rear cover 16 can be omitted. In the present embodiment, because all of the first holes 31 a and the second holes 31 b are located outside of the storing chamber 32, the interior of the storing chamber 32 cannot fluidly communicate with the exterior due to the arrangement of the first holes 31 a and the second holes 31 b. Furthermore, because the first holes 31 a and the second holes 31 b are located outside of the ring-shaped sealing element 18, the first holes 31 a and the second holes 31 b is in fact separated from the storing chamber 32 and does not communicate with it. In this way, a possibility that gas from the exterior enters into the storing chamber 32 via the first holes 31 a and the second holes 31 b is eliminated. That is, these first and second holes 31 a, 31 b cannot have a negative effect on the air tightness of the storing chamber 32, such that the air tightness of the low-pressure storage unit 7 is improved.

When the low-pressure storage unit 7 is in the low-pressure state, the top wall 21 and the bottom wall 23 of the box body 11 endure a larger pressure than the other walls of the low-pressure storage unit 7. In order to improve the pressure enduring capability of the top and bottom walls 21 and 23 and to reduce their deformation, according to a preferred embodiment of the present invention, the top wall 21 and the bottom wall 23 each are provided with a plurality of reinforcement structures 34a, 34b and 34c, which are spaced apart from each other.

Since the top wall 21 is symmetrical to the bottom wall 23, only the top wall 21 as an example is explained particularly here.

In the present embodiment, the above-mentioned reinforcement structures 34a, 34b and 34c are obtained in that the top wall 21 is rugged and has a constant thickness. The inertia moment of the top wall 21 can be varied by changing the cross sectional shape of the top wall 21 , such that the pressure enduring capability of the top wall 21 is improved. This facilitates reducing the use of material without significantly increasing the manufacturing step. For example, these reinforcement structures can be obtained by stamping the box body 11 during its production.

Preferably, the reinforcement structures 34a, 34b and 34c are formed by protrusions which protrude outwardly from the top wall 21 . This facilitates increasing the holding capacity of the storing chamber 32. Further, because these reinforcement structures 34a, 34b and 34c are depressed outwardly at their inner sides, the influence of the reinforcement structures 34a, 34b and 34c on the internal appearance of the storing chamber 32 can be reduced in the case that the low-pressure storage unit 7 is inserted in the preservation compartment 4. In the present embodiment, each protrusion is in the form of a boss. Each boss is substantially of the same height.

These reinforcement structures 34a, 34b and 34c include two first reinforcement structures 34a, 34c which are provided along the front opening 25 and the rear opening 26 respectively. The first reinforcement structures 34a, 34c are continuous and each extend from a first longitudinal central axis X, extending perpendicular to the front and rear openings 25 and 26 and in a fore-and-aft direction, of the top wall 21 toward opposite lateral sides by at least one fourth of a lateral width W of the top wall 21 , such that the central portion which will be greatly deformed can be effectively reinforced.

Preferably, the length Wa of the first reinforcement structure 34a and the length Wc of the first reinforcement structure 34c are at least over three fourth of the lateral width W of the top wall 21 . In the present embodiment, both ends of each of the first

reinforcement structures 34a, 34c are close to both sides of the top wall 21 respectively, such that the length of each first reinforcement structure is approximate to the width W of the top wall 21 . It is preferable that each of the first reinforcement structures 34a, 34c is provided symmetrically with respect to the first central axis X.

The length Wa of the first reinforcement structure 34a is substantially identical with the length Wc of the first reinforcement structure 34c. The first reinforcement structure 34a adjacent the front opening 25 is in the form of an elongated strip. The length in the fore-and-aft direction of the other first reinforcement structure 34c adjacent the front opening 26 is larger than that of the first reinforcement structure 34a, and the first reinforcement structure adjacent the rear opening has a larger area than the first reinforcement structure adjacent the front opening. In the present embodiment, the area of the first reinforcement structure 34c is more than one fourth of the area of the top wall 21 . The front end of the first reinforcement structure 34c has an arcuate contour and thus is generally U-shaped. Between the two first reinforcement structures 34a, 34c, the top wall 21 is provided with one second reinforcement structure 34b. The second reinforcement structure 34b is located at the central region of the top wall 21 and extends from the first longitudinal central axis X toward opposite lateral sides by at least one eighth of the lateral width W of the top wall 21 . It is preferable that the second reinforcement structure 34b is provided symmetrically with respect to the first central axis X. The length in a direction parallel to the front opening 25 of the second reinforcement structure 34b is between one fourth and one half of the lateral width W of the top wall 21 . The second reinforcement structure 34b has an arcuate contour. In the present embodiment, it is generally oval. The length in the direction parallel to the front opening 25, 26 of the second reinforcement structure 34b is more than its length in the direction of the first central axis X. The second reinforcement structure 34b lies generally in the U-shaped region of the first reinforcement structure 34c and is enclosed by it.

Because each of the first reinforcement structures 34a, 34c extends from the first longitudinal central axis X of the top wall 21 toward opposite lateral sides by at least one fourth of the lateral width W of the top wall 21 and the second reinforcement structure 34b extends from the first longitudinal central axis X of the top wall 21 toward opposite lateral sides by at least one eighth of the lateral width W of the top wall 21 , the cross-sectional moment of inertia of the region that is greatly deformed can be effectively increased in the case that the box body 11 has the front and rear openings 25, 26.

As shown in figure 6, in a cross section of the top wall 21 along the first central axis X and in several cross sections which are parallel with the cross section and provided with the second reinforcement structure 34b, concave and convex portions alternate more densely in the front half region of each cross section than in the rear half region thereof. This facilitates reducing the deformation amount in the front half region of the top wall 21 , and thus facilitates reducing the deformation amounts of the front jointing element 17 and of the door 10 which may be noticed by the user. Because the reinforcement structures 34a, 34b and 34c are of different shapes, for example the first reinforcement structure 34a adjacent the front opening 25 is trip-shaped, the second reinforcement structure 34b in the central region of the top wall 21 is oval and the first reinforcement structure 34c extending forwards adjacent the rear opening 26 has an U-shaped portion which encloses the second reinforcement structure 34b, it is possible that the rugged shape presents in more cross sections of the top wall 21 with only limited reinforcement structures being provided thereon.

Claims

1. A low-pressure storage unit (7) for a refrigeration appliance (1 ), wherein the low-pressure storage unit (7) comprises an evacuable storing chamber (32), characterized in that the storing chamber (32) has at least one wall (21 , 23) which is made of metal and has a plurality of reinforcement structures (34a, 34b, 34c) that are spaced apart from one another.

2. The low-pressure storage unit (7) according to claim 1 , characterized in that the wall (21 , 23) has a constant thickness but is rugged to form the reinforcement structures (34a, 34b, 34c).

3. The low-pressure storage unit (7) according to claim 1 or 2, characterized in that the reinforcement structures (34a, 34b, 34c) are formed by protrusions that protrude outwardly from the wall (21 , 23).

4. The low-pressure storage unit (7) according to claim 3, characterized in that the reinforcement structures (34a, 34b, 34c) are formed by stamping.

5. The low-pressure storage unit (7) according to any one of the preceding claims, characterized in that the plurality of reinforcement structures (34a, 34b, 34c) are of different shapes, and that at least one (34b, 34c) of the reinforcement structures has an arcuate contour.

6. The low-pressure storage unit (7) according to any one of the preceding claims, characterized in that among the plurality of reinforcement structures (34a, 34b, 34c), at least one reinforcement structure (34b) is at least partially surrounded by another one or more reinforcement structures (34c).

7. The low-pressure storage unit (7) according to any one of the preceding claims, characterized in that the wall (21 , 23) has the reinforcement structure (34b) at its central region.

8. The low-pressure storage unit (7) according to any one of the preceding claims, characterized in that the wall (21 , 23) is formed by a first member (11 ) which is of a box-structure and is made of metal, and that the first member (11 ) has an opening (25, 26) on at least one side thereof.

9. The low-pressure storage unit (7) according to claim 8, characterized in that the plurality of reinforcement structures (34a, 34b, 34c) include at least one first reinforcement structure (34a, 34c) provided along an edge of the opening (25, 26).

10. The low-pressure storage unit (7) according to claim 8, characterized in that the plurality of reinforcement structures (34a, 34b, 34c) include such a first reinforcement structure (34a, 34c) that is provided along an edge of the opening (25, 26) and extends from a first longitudinal central axis (X), which is perpendicular to the opening (25, 26), of the wall (21 , 23) toward opposite lateral sides by at least one fourth of a lateral width (W) of the wall (21 , 23).

11 . The low-pressure storage unit (7) according to claim 9 or 10, characterized in that the first reinforcement structure (34a, 34c) has a length (Wa, Wc) which is at least three fourths of the width (W) of the wall (21 , 23).

12. The low-pressure storage unit (7) according to claim 11 , characterized in that the first reinforcement structure (34a, 34c) is provided symmetrically with respect to the first central axis (X), and that both ends of the first reinforcement structure are close to both sides of the wall (21 , 23) respectively.

13. The low-pressure storage unit (7) according to any one of claims 9 to 12, characterized in that the first reinforcement structure (34a) is in the shape of an elongated strip, and that the first reinforcement structure is provided adjacent a door (10) for selectively closing or opening the opening (25).

14. The low-pressure storage unit (7) according to any one of claims 8 to 13, characterized in that the plurality of reinforcement structures (34a, 34b, 34c) include a second reinforcement structure (34b) which is disposed in the central region of the wall (21 , 23), and that the second reinforcement structure (34b) extends from a first longitudinal central axis (X), which is perpendicular to the opening (25, 26), of the wall (21 , 23) toward opposite lateral sides by at least one eighth of a lateral width (W) of the wall (21 , 23).

15. The low-pressure storage unit (7) according to claim 14, characterized in that the second reinforcement structure (34b) has a contour which is at least partially arcuate.

16. The low-pressure storage unit (7) according to claim 15, characterized in that the second reinforcement structure (34b) is generally oval, and that the length, in a direction parallel to the opening (25, 26), of the second reinforcement structure (34b) is larger than the length, in a direction perpendicular to the opening (25, 26), thereof.

17. The low-pressure storage unit (7) according to any one of claims 8 to 16, characterized in that it further comprises a second member (16, 17) which is connected to the first member (11 ) along the opening (25, 26) and is made of plastic.

18. The low-pressure storage unit (7) according to any one of the preceding claims, characterized in that the evacuable storage room (32) is of a flat structure, and that the wall (21 , 23) comprises a top wall and/or a bottom wall of the storing chamber (32).

19. The low-pressure storage unit (7) according to any one of the preceding claims, characterized in that the thickness of the walls (21 , 23) is not more than 4 millimeters, for example is in a range of 2 to 2.5 millimeters.

20. A refrigeration appliance (1 ), comprising a storage compartment (4) and a low-pressure storage unit (7) which is received in the storage compartment (4) and is claimed according to any one of the preceding claims.