EP2879552B1

EP2879552B1 - Refrigerated sales cabinet

Info

Publication number: EP2879552B1
Application number: EP12741010.8A
Authority: EP
Inventors: Oliver Stakelbeck
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 2012-08-01
Filing date: 2012-08-01
Publication date: 2017-07-19
Anticipated expiration: 2032-08-01
Also published as: CN104640482A; EP2879552A1; WO2014019622A1; CN104640482B

Description

The present invention relates to a refrigerated sales cabinet.
A refrigerated sales cabinet as it is known in the art comprises a cabinet body, side panels, a door frame and at least one door, wherein the side panels are installed on the sides of the cabinet body, the door frame is installed on the cabinet body, the door is installed on the door frame, and sealing strips are provided between the cabinet door and the door frame.
The front surface of the door frame, which is exposed to ambient conditions, is cooled when the refrigerated sales cabinet is operated and humid ambient air condensates at this front surface causing water droplets to appear, which is uncomfortable for the customers. Therefore, there is a need to prevent the temperature of this surface to fall below the dew point temperature.
A door frame according to the prior art comprises an electrical heating element, which serves to keep the temperature of the front surface above the dew point in order to prevent the condensation of water on the door frame. The electrical energy consumed by such an electrical heating element is very high and considerably contributes to the total energy consumed by the refrigerated sales cabinet in operation.
US 4 891 912 A discloses a refrigerator door assembly having a thermally efficient door mounting frame which includes a forward structural frame member mounted within the opening of a refrigerator cabinet for providing an attractive finished appearance for the frame, a separate rear structural frame member for establishing a door closure sealing surface against which doors of the assembly close and which may be made of less expensive and/or less heat conductive material than the forward structural frame member, and a flexible plastic barrier sheet interposed between the forward and rear structural members for thermally insulating the structural members from each other. Stitch like connections are formed from adjacent connecting flanges of the forward and rear structural members together without substantial contact therebetween. Various magnetically attractable sealing strip arrangements are disclosed that are adapted for use in low temperature refrigeration units without condensation or frost build up.
It therefore would be beneficial to reliably avoid condensation at the front surface of a door frame of a refrigerated sales cabinet, whereas at the same time the electrical energy consumption is minimized.
A refrigerated sales cabinet according to the invention comprises a cabinet body providing a refrigerated sales space for supporting refrigerated goods to be sold therein; a door frame having a top post, a bottom post, and at least two upright posts; and at least one door. Each of said upright posts has a cold main body providing a structural frame member, which is cooled to low temperatures when the refrigerated sales cabinet is operated as it is exposed to the cooled goods presentation space, and an insulating front element. Said cold main body has a basically C-shaped cross section comprising a rear portion and two side portions, which are arranged basically parallel to each other and perpendicular to the rear portion. Said insulating front element comprises, from back to front, a rear panel attached to the cold main body, a layer of a thermally insulating nanoporous aerogel material, and a front panel forming the front surface of the post. Said insulating front element provides a thermal insulation against the cold main body of the post and thereby avoids condensation at the front surface of the front panel. Each of said at lest two upright posts comprises an internal support member arranged within the cold main body extending basically parallel to the rear portion and providing an elongated first hollow space within the cold main body. Said first hollow space being defined by the internal support member, the rear portion and the two side portions. A front side of the internal support member facing the at least one door is provided with two first bracket members extending opposite to each other in a plane extending basically parallel to the plane of the at least one door when it is arranged in a closed position parallel to the door frame. Said insulating front element is mounted to a front side of the internal support member facing the at least one door by means of two second bracket members provided at the rear side of the rear panel and engaging with the first bracket members provided at the internal support member. The disclosure of the invention will become more easily understood with reference to the accompanying drawings. It is appreciated by those skilled in the art that the accompanying drawings are exemplary only and are not intended to limit the scope of protection of the invention. In the drawings:

Fig. 1 shows an exploded view of a refrigerated sales cabinet of the front-access type with doors and a door frame according to an embodiment of the invention, and
Fig: 2 shows a horizontal cross section through one of the upright posts of the door frame and part of adjacent doors.

Figs. 1 and 2 and the following discussion describe particular embodiments of the invention so as to teach those skilled in the art how to produce and use the best modes of the invention. In order to teach the principle of the invention, several conventional aspects have been simplified or omitted. Those skilled in the art should understand that variations originating from these embodiments also fall within the scope of the invention. Those skilled in the art should understand that the features to be described below can be combined in various ways so as to form numerous variations of the invention. Therefore, the invention is not limited to the following particular embodiments and is merely defined by the appended claims and their equivalents.
A refrigerated sales cabinet 20 of the front-access type with doors 14 and a door frame 21 according to an exemplary embodiment of the invention is shown in Fig. 1.
The refrigerated sales cabinet 20 as shown in Fig. 1 comprises a cabinet body 22, a left side panel 30, a right side panel 31, a door frame 21 and a plurality of doors 14. The cabinet body 22 comprises a bottom part 26, a roof plate 24, a rear wall 27 and a plurality of shelves 28 arranged in between.
A complete refrigeration circuit comprising a compressor, a condenser, an expansion device and an evaporator may be installed in the cabinet body 22, in order to provide a standalone refrigerated cabinet which only needs to be connected to an electric power supply for operation.
Alternatively, only one or more evaporators may be installed within the cabinet body 22, the evaporators being configured to be fluidly connected to an external refrigeration circuit provided in the building in which the refrigerated sales cabinet is to be installed.
The refrigerated sales cabinet may be a cooling sales cabinet which is configured to cool the goods presentation space to cooling temperatures above 0°C.
Alternatively, the refrigerated sales cabinet may be a freezing sales cabinet, which is configured to cool the goods presentation space to freezing temperatures below 0 °C, in particular to temperatures below -15 °C in order to store and present frozen goods to potential customers.
The left side panel 30 and the right side panel 31 are respectively installed on the left and right hand side of the cabinet body 22. The door frame 21, which comprises a plurality of vertical extending upright posts 32, a horizontal top post 34 and a horizontal bottom post 36, respectively connecting the upright posts 32 to each other, is installed on a front side of the cabinet body 22.
A plurality of cabinet doors 14 is installed on the front side of the door frame 21. The cabinet body 22, the left side panel 30, the right side panel 31, the door frame 21 and the cabinet doors 14 are installed together to form a refrigerated goods storage and presentations space which is closed by and accessible through the doors 14.
Figure 2 shows a horizontal cross section through one of the upright posts 32 of the door frame 21 and portions of two adjacent doors 14.
The doors 14 are for example insulated glass doors 14 respectively comprising two glass panels 16 separated by an intermediate vacuum layer 16a. The glass panels 16 are supported by an outer frame member 15, which may be an extruded element made of plastic or metal, for example aluminium. According to the invention each upright post 32 includes a main body 4 providing a structural frame member. Said frame member may be made of aluminium or another high strength material and which is cooled to low temperatures when the refrigerated sales cabinet 20 is operated as it is exposed to the cooled goods presentation space, and an insulating front element 9. The cross section of the cold main body 4 is basically C-shaped, when looked at in the cross-section, comprising a rear portion 4a and two side portions 4b.
The side portions 4b are arranged basically parallel to each other and perpendicular to the rear portion 4a. An internal support member 6 is arranged within the cold main body 4 extending basically parallel to the rear portion 4a and providing an elongated first hollow space 5 within the cold main body 4, the first hollow space 5 being defined by the internal support member 6, the rear portion 4a and the two side portions 4b. Optionally, the first hollow space 5 may be filled with an insulating material, e.g. a thermally insulating foam, in order to enhance the thermally insulating properties of the upright post 32.
A front side of the internal support member 6 facing the doors 14 is provided with two first bracket members 8 extending opposite to each other in a plane extending basically parallel to the plane of the doors 14 when they are arranged in the closed position parallel to the door frame 21. An insulating front element 9 is mounted to the internal support member 6 by means of corresponding second bracket members 13 provided at the rear side of the rear panel 10 engaging with the first bracket members 8 provided at the internal support member 6. The mutual engagement of the bracket members 8, 13 allows a convenient and secure installation of the insulating front element 9 within the cold main body 4 of the upright post 32.
The insulating front element 9 includes a rear panel 10 facing the internal support member 6 and comprising the corresponding second bracket members 13. The rear panel 10 is basically planar comprising side wall strips 10a so as to have a C-shape when looked at in the cross-section and extends basically parallel to the rear portion 4a of the cold main body 4 spanning the distance between the two side portions 4b, thereby providing two further elongated hollow spaces 7, which are respectively defined by the rear panel 10 of the insulating front element 9, one of the side portions 4b of the cold main body 4 and the internal support member 6.
A layer comprising a nanoporous aerogel 12 is provided on the front side of the C-shaped rear panel 10 of the insulating front element 9 facing the doors 14.
The insulating front element 9 further comprises a basically planar front panel 11, which is provided on the front side of the nanoporous aerogel 12 facing the doors 14 opposite to the rear panel 10. As a result, the nanoporous aerogel 12 is enclosed within the insulating front element 9 in between the rear panel 10 and the front panel 11. This enclosure within the insulating front element 9 protects the nanoporous aerogel 12 from being damaged, e.g. by the doors 14 or clumsy customers hitting the upright post 32, and further allows an easy installation of the nanoporous aerogel 12 at the cold main body 4 of the upright post 32.
The first and second panels 10, 11 of the insulating front element 9 may be made of any suitable plastic or metallic material, e.g. Aluminium or PVC, or a combination thereof.
Sealing elements 18, which may be made of an elastic material such as rubber, are mounted to front panel 11 of the insulating front element 9 about the periphery of the door openings for defining a sealing and stop surface for the doors 14 in order to provide an air seal between the doors 14 and the upright post 32 of the door frame 21, when the doors 14 are in their respective closed positions. Alternatively or additionally sealing elements 18 may be mounted to the doors 14. The sealing elements 18 are configured to prevent the exchange of cool air from the refrigerated goods storage and presentation space of the refrigerated sales cabinet 20 with warm ambient air.
A magnet 19 may be provided in, on or below the sealing element 18 in order to attract the metallic outer frame member 15 locking the doors 14 securely in the closed position in order to avoid an undesired opening of the doors 14. If the outer frame member 15 is made of plastic or a non magnetic metal, a further magnet 17 or an element 17 comprising a magnetic metal may be provided in or on the outer frame member 15 in order to be attracted by the magnet 19 provided in on or below the sealing element 18.
Alternatively or additionally a mechanical lock, which is not shown in the figures, may be provided in order to securely lock the doors 14.
An exemplary embodiment of the invention has been described with reference to the upright posts 32 of the door frame 21. The skilled person, however, will easily understand that the idea of the invention may be analogously applied to the top and bottom posts 34, 36, which extend horizontally between the upright posts 32, as well, in order to avoid the generation of condensation water on the complete front surface of the door frame 21.
According to exemplary embodiments, as explained herein, a thermally insulating front element is positioned at the front of at least one of the posts of the door frame of the refrigerated sales cabinet, in order to avoid the heat transfer through the upright post and to keep the front surface temperature above the dew point. In particular, such thermally insulating front element comprises a layer of nanoporous aerogel material having a porous structure and providing exceptional thermal insulation properties. Due to the exceptional thermal insulation properties it is not necessary to heat the door frame in order to avoid condensation of ambient air at the door frame.
The inventors have discovered that instead of heating the posts of the door frame of a refrigerated sales cabinet, an insulating front element as defined in the claims and as described herein can be provided, which is - contrary to what was believed until the present invention was made - capable to reliably avoid condensation at the front surface of such posts. Until the point in time when the present invention was made, there was no insulating front element known or available which could reliably avoid condensation at the front surface of such posts while being subject to constant cooling from the back of the refrigerated sales cabinet. None of the available insulating techniques was able to provide a sufficient insulation at that particular position that could reliably avoid condensation over time.
In an embodiment the nanoporous aerogel material of the layer of nanoporous aerogel material has a porous structure with a pore size in the range of some nanometers, particularly of 1 to 10 nanometers. A nanoporous aerogel material having a porous structure with a pore size in said range comprises good thermally insulating properties. In particular, the thermal insulation properties of such a nanoporous aerogel are better than those of any classical thermal insulation materials as they are known to be used for the insulation of buildings, for example.
Aerogel materials are synthetic porous materials derived from a gel, in which the liquid component of the gel has been replaced with a gas. Aerogel materials are solids with an extremely low density and an extremely low thermal conductivity. Aerogel materials often have a translucent nature and feel like expanded polystyrene (styrofoam) to the touch. Aerogel materials are produced by extracting the liquid component of a gel through supercritical drying. This allows liquid to be slowly drawn off without causing the solid matrix in the gel to collapse from capillary action, as would happen with conventional evaporation.
Aerogel materials are rigid, dry materials and do not resemble a gel in their physical properties. Aerogel materials can have a dentritic microstructure in which spherical particles of average size of 2-5 nm are fused together into clusters. These clusters form a three-dimensional highly porous structure of almost fractal chains. The average size and density of the pores can be controlled during the manufacturing process.
The nanoporous aerogel materials are good thermal insulators because they have a very small heat transfer in regard of convection, conduction and radiation. They are good conductive insulators because they are composed almost entirely from a gas, and gases are very poor heat conductors.
A particularly suitable nanoporous aerogel material is a silica aerogel material, which is a silica-based substance, derived from silica gel. The lowest density aerogel is a silica nanofoam of 1 mg/cm³. The density of air is 1.2 mg/cm³ (at 20°C and 1 atm). By convention, the mass of air is excluded when the micro-lattice density is calculated. Allowing for the mass of the interstitial air, the true, unevacuated density of the micro-lattice is approximately 2.1 mg/cm³. The silica aerogel material has remarkable thermal insulative properties, having an extremely low thermal conductivity: from 0.03 W/mK down to 0.004 W/mK.
An example of a suitable nanoporous aerogel material is formed by the nanoporous silica aerogel insulation mat named Spaceloft manufactured by the company Aspen Aerogel.
In an embodiment said layer of nanoporous aerogel material is sandwiched between said rear panel and said front panel. In an alternative embodiment said rear panel and said front panel together with two respective side wall strips completely enclose said layer of nanoporous aerogel material. Such a configuration securely fixes the nanoporous aerogel material and protects it from being damaged. It further allows an easy and convenient installation of the nanoporous aerogel material.
In an embodiment the rear panel and/or the front panel comprise a plastic material, particularly PVC. A plastic material, such as PVC, provides a cheap lightweight material with good thermal insulating properties.
In an embodiment the insulating front element is attached to the cold main body of the post by means of a snap-on connection, particularly by a fastening bracket provided at the rear side of the rear panel that engages with a corresponding fastening bracket provided at the cold main body. A snap-on connection allows an easy installation and deinstallation of the front element to and from the post, respectively.
Optionally the fastening bracket may be provided in the form of a rail extending along the length of the post. Such a rail may be produced by extrusion and provides a secure fixture over the whole length of the post.
In an embodiment the door is formed as a pivotable door being pivotable between a closed position and at least one open position, said pivotable door having a first side portion connected with a hinge and a pivotable second side portion opposite to the first side portion. In the closed position the door rests with the rear side of its second side portion against one of the upright posts, and with the rear sides of its upper and lower portions against the top and bottom posts, respectively. A pivotable door in its closed position isolates the refrigerated sales space from the environment in order to avoid cold air from flowing out of the refrigerated sales space thereby reducing the energy needed for cooling the refrigerated sales space. In its open position a pivotable door allows an easy and convenient access to the refrigerated sales space and the goods stored and presented therein.
In an embodiment the rear sides of the second side portion, of the upper portion and/or of the lower portion of the door, that, in the closed position of the door, respectively rest against the upright, top and/or bottom posts, are respectively provided with sealing elements, and/or the front sides of the upright, top and/or bottom posts are respectively provided with sealing elements. Sealing elements provided between the door and the posts enhance the insulating properties of the door in its closed position.
The front surface of the upright post may provide a stop for the door in order to define the position of the door in its closed position.
In an embodiment the second side portion of the door and the associated upright post, particularly a sealing element provided at the associated upright post, comprise a pair of two magnets or a combination of a magnet and an element of magnetic material, in order to hold the door in its closed position. Such an arrangement of at least two magnets and/or a magnet and an element of magnetic material reliably prevents the door from being accidentally opened or not completely closed, which would allow cold air to flow out of the refrigerated sales space thereby increasing the energy needed for cooling the refrigerated sales space.
In an embodiment at least one pair of two doors with mirror-inverted pivoting directions is provided, one door being arranged besides the other, wherein the pivotable second end portions of both doors are facing each other, such that both doors, in their respective closed positions, rest with the rear sides of their second side portions against the same upright post. Such an arrangement of adjacent doors allows a convenient access to the goods stored within the refrigerated sales space.
In an embodiment the doors respectively comprise at least one pane of glass, allowing to look into the refrigerated sales space without opening at least one of the doors.
In an embodiment the refrigerated sales cabinet is configured to cool the refrigerated sales space down to freezing temperatures below 0 °C, in particular to temperatures below -15 °C. This allows to store and present frozen goods to potential customers. Good thermal insulation properties of the insulating front element are in particular important at such low temperatures in order to reduce condensation at the front surface of the refrigerated sales cabinet.
The refrigerated sales cabinet may be a standalone refrigerated cabinet comprising a complete refrigeration circuit which needs to be connected only to an electric power supply for operation. Alternatively the refrigerated sales cabinet may comprise only at least one evaporator to be fluidly connected to an external refrigeration circuit which is installed in the building in which the refrigerated sales cabinet is placed.
While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention is not limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

List of Reference Numerals

4: main body of a post
4a: rear portion of a post
4b: side portions of a post
5: first hollow space
6: support member
7: second hollow space
8: first fastening bracket
9: insulating front element
10: rear panel
10a: side wall strip
11: front panel
12: layer of nanoporous aerogel material
13: second fastening bracket
14: door
15: outer frame member
16: door panel
16a: vacuum layer
17: magnet or element comprising magnetic metal
18: sealing strip
19: magnet
20: refrigerating sales cabinet
22: cabinet body
21: door frame
24: roof plate
26: bottom part
27: rear wall
28: shelves
30: left side panel
31: right side panel
32: upright post
34: top post
36: bottom post

Claims

Refrigerated sales cabinet (20), comprising:
a cabinet body (22) providing a refrigerated sales space for supporting refrigerated goods to be sold therein;

a door frame (21) having a top post (34), a bottom post (36), and at least two upright posts (32);

at least one door (14);

wherein each of said at least two upright posts (32) has a cold main body (4) and an insulating front element (9), wherein said cold main body (4) has a basically C-shaped cross section comprising a rear portion (4a) and two side portions (4b), which are arranged basically parallel to each other and perpendicular to the rear portion (4a),

said insulating front element (9) comprising, from back to front, a rear panel (10) which is attached to the cold main body (4), a layer comprising a nanoporous aerogel material (12), and a front panel (11) forming the front surface of the post (32, 34, 36),

said insulating front element (9) providing a thermal insulation against the cold main body (4) of the post (9) wherein each of said at least two upright posts (32) comprises an internal support member (6) arranged within the cold main body (4) extending basically parallel to the rear portion (4a) and providing an elongated first hollow space (5) within the cold main body (4), the first hollow space (5) being defined by the internal support member (6), the rear portion (4a) and the two side portions (4b), wherein a front side of the internal support member (6) facing the at least one door (14) is provided with two first bracket members (8) extending opposite to each other in a plane extending basically parallel to the plane of the at least one door (14) when it is arranged in a closed position parallel to the door frame (21), and wherein the insulating front element (9) is mounted to the front side of the internal support member (6) facing the at least one door (14) by means of two second bracket members (13) provided at the rear side of the rear panel (10) and engaging with the first bracket members (8) provided at the internal support member (6).
Refrigerated sales cabinet (20) of claim 1, wherein the nanoporous aerogel material (12) of the layer has a porous structure with a pore size in the range of some nanometers, particularly of 1 to 10 nanometers.
Refrigerated sales cabinet (20) of claim 1 or 2, wherein the nanoporous aerogel material is a silica aerogel material being a silica-based substance, derived from silica gel, and having a thermal conductivity between 0.03 W/mK and 0.004 W/mK.
Refrigerated sales cabinet (20) of any of the preceding claims, wherein said layer of nanoporous aerogel material (12) is sandwiched between said rear panel (10) and said front panel (11), and/or wherein said rear panel (10) and said front panel (11) together with two respective side wall strips (10a) completely enclose said layer of nanoporous aerogel material (12).
Refrigerated sales cabinet (20) of any of the preceding claims, wherein the rear panel (10) and/or the front panel (11) comprise a plastic material, particularly PVC.
Refrigerated sales cabinet (20) of any of the preceding claims, wherein the insulating front element (9) is attached to the cold main body (4) of the post (32, 34, 36) by means of a snap-on connection (8, 13), particularly by a second fastening bracket (13) provided at the rear side of the rear panel (10) that engages with a corresponding first fastening bracket (8) provided at the cold main body (4).
Refrigerated sales cabinet (20) of any of the preceding claims, wherein the door (14) is formed as a pivotable door (14) being pivotable between a closed position and at least one open position, said pivotable door (14) having a first side portion connected with a hinge and a pivotable second side portion opposite to the first side portion; and/or wherein the door (14), in the closed position, rests with the rear side of its second side portion against one of the upright posts (32), and with the rear sides of its upper and lower portions against the top and bottom posts (34, 36), respectively.
Refrigerated sales cabinet (20) of claim 7, wherein the rear sides of the second side portion, of the upper portion and/or of the lower portion of the door (14) that respectively rest against the upright, top and/or bottom posts (32, 34, 36), when the door (14) is in its closed position, are provided with at least one sealing element (18), and/or wherein the front sides of the upright, top and/or bottom posts (32, 34, 36) are respectively provided with at least one sealing element (18).
Refrigerated sales cabinet (20) of claim 7 or 8, wherein the second side portion of the door (14) and the associated upright post (32), particularly a sealing element (18) provided at the associated upright post (32), comprise a pair of two magnets (17, 19) or a combination of a magnet (17) and an element (19) comprising a magnetic material, in order to hold the door (14) in the closed position.
Refrigerated sales cabinet (20) of any of claims 7 to 9, wherein at least one pair of two doors (14) with mirror-inverted pivoting directions is provided, one besides the other, wherein the pivotable second end portions of both doors (14) are facing each other, such that, in the closed position, both doors (14) rest with the rear sides of their second side portions against the same upright post (32).
Refrigerated sales cabinet (20) of any of the preceding claims, wherein the refrigerated sales cabinet (20) is configured to cool the refrigerated sales space down to freezing temperatures below 0 °C, in particular to temperatures below -15 °C.