GB2387897A

GB2387897A - Cold storage appliance

Info

Publication number: GB2387897A
Application number: GB0316697A
Authority: GB
Inventors: Ian David Wood
Original assignee: Applied Design and Engineering Ltd
Current assignee: Applied Design and Engineering Ltd
Priority date: 2000-09-13
Filing date: 2001-03-13
Publication date: 2003-10-29
Anticipated expiration: 2021-03-13
Also published as: GB2387897B; GB2368898A; GB2368898B; GB0118281D0; GB0316697D0

Abstract

A cold storage appliance includes at least one container, and a structure defining a vapour-sealable container compartment from which the container can be withdrawn to open the container and afford access to its interior and to which the container can be returned to close the container for cold storage of any items within the container. Valve means communicate with the container compartment to admit air through duct 358 to the container compartment when the container is being withdrawn from the container compartment, the air being supplied from outside the appliance via duct 350 and valve member 352; or to expel air (see Fig.2c not shown) outside the appliance through valve member 356 and exhaust duct 354 when the container is being returned to the container compartment. The valve means allows a vapour seal to be maintained within the container compartment when the container is positioned within the container compartment.

Description

IMPROVEMENTS IN OR RELATING TO COLD STORAGE

The invention herein relates to the art of cold storage, including appliances such as refrigerators and freezers for storing foodstuffs and other perishables. Other applications - 5 of the invention include storage of chemicals and medical or biological specimens. The invention also finds use in mobile applications, for example in the bulk transport and storage of perishable goods.

The invention develops and adds to the various features of the Inventor's co-pending 10 International Patent Application No. PCT/GB00/03521, the contents of which are incorporated herein by reference. As in that specification, the invention can be applied to

storing any items within a cooled environment, such as in a refrigerated goods vehicle.

The term 'appliance' is therefore to be construed broadly, extending beyond fixed domestic devices into industrial, scientific and mobile applications.

Briefly to recap the introduction of PCT/GB00/0352 1, the advantages of storing foodstuffs

and other perishable items in refrigerated and segregated conditions have long been known: refrigeration retards the degradation of such items and segregation helps to prevent their cross-contamination. Accordingly, modern cold-storage appliances such as 20 refrigerators and freezers are usually compartmentalized, albeit not often effectively, so that a user can store different types of food in different compartments. All such appliances have the additional aim of maximising their energy efficiency.

US Patent No. 1,337,696 to Ewen is a prior art document cited as technological

25 background against PCT/GB00/03521. Ewen speaks of segregation between refrigerated

drawers contained in a surrounding cabinet and employs refrigerating units placed immediately and closely above each drawer... so that said drawer may in effect be said to be closed against said refrigerating unit'. However, there has to be a gap left between the drawer and the refrigerating unit if the drawer is going to open. That gap will promote 30 icing as moist air within the cabinet migrates into the drawer and the water vapour condenses and freezes. The smaller the gap, the sooner the accumulating ice will prevent drawer movement. If a larger gap is tried instead, there will be a greater spillage of air and hence the refrigerator will be less energy-efficient and more susceptible to cross

-2 contamination. That aside, the spillage of cold air in Ewen lowers the temperature within the cabinet around the drawers, and so increases the likelihood of condensation on the drawers when 5 opened. It will be noted that cold air spilled in this way can fall freely behind the drawers within the cabinet and so expose the exterior of the drawers to air substantially below ambient temperature. Certain design details of Ewen worsen this effect. For example, the bottom wall of the Ewen unit is an efficient insulator which will significantly reduce the surface temperature of the drawers. Also, the internal divisions between the drawers do not 10 allow for ambient heat transfer to the drawers but only for heat transfer between the drawers, thus promoting drawer-to-drawer temperature equalisation over time. Left for long periods, or even overnight, large parts of the external surface of each drawer will fall to temperatures significantly below ambient dew point. Condensation or ice will therefore Loran on those surfaces as soon as the drawers are opened; similarly, if the drawers are 15 removed and left outside the appliance, they will start to 'sweat' with condensation.

Opening and closing a drawer within a sealed cabinet in Ewen acts like a piston, alternately applying both negative and positive pressures to adjacent areas. This promotes air transfer through the drawer opening at the front of the cabinet, which can displace cold 20 treated air in a drawer, and within the cabinet itself An over-sized cabinet would reduce the piston effect but would also be wasteful of space. Conversely, a more space-effcient close-ftting cabinet may decrease the displacement of cold treated air, and so reduce the burden of cooling the warmer air that takes its place, but it will increase resistance to opening and closing the drawer.

Cold air spillage aside, the gap inevitably left between a drawer and its associated lid in prior art arrangements is large enough to allow the passage of enzymes, spores and other

airborne contaminants. Also, Ewen discloses a common interconnecting drain and this too would allow free transfer of contaminants between each drawer, particularly under the 30 aforementioned piston action.

It is against this background that the present invention has been devised.

-3 The invention resides in a cold-storage appliance including: at least one container; a structure defining a vapour-sealable container compartment from which the container can be withdrawn to open the container and afford access to its interior and to which the 5 container can be returned to close the container for cold storage of any items within the container; and valve means communicating with the container compartment to admit air from outside the appliance when the container is being withdrawn from the container compartment, to expel air outside the appliance when the container is being returned to the container comparunent, and to maintain a vapour seal with the container compartment 10 when the container is within the container compartment. This mitigates the piston effect which could otherwise promote cross-contamination between containers in a multi-

container arrangement.

The valve means may comprise an inlet duct closable by an inlet valve member, an 15 exhaust duct closable by an exhaust valve member, and an intermediate duct connected to the container compartment that communicates with a central valve chamber disposed between the inlet valve member and the exhaust valve member. In that arrangement, the inlet valve member can normally rest on an inlet valve seat around a port between the inlet duct and the central valve chamber, and open into the central valve chamber.

20 Similarly, the exhaust valve member can normally rest on an exhaust valve seat around a port between the exhaust duct and the central valve chamber, and open into the exhaust duct. The inlet valve member and the exhaust valve member are suitably in their respective rest positions when the container is static.

25 The invention preferably achieves the effect that when the container is being opened, the inlet valve member opens and admits air from the inlet duct to flow into the container compartment. Conversely, when the container is being closed, it is preferred that air forced from the container compartment causes the exhaust valve member to open and is exhausted out of the exhaust duct.

The inlet duct suitably draws ambient air from outside the appliance and the exhaust duct suitably exhausts air to outside the appliance.

The valve members may be rigid flaps or plates, and may rely upon gravity and pressure differences to close. It is also possible for the valve members to be resilient curved diaphragms whose resilience and curvature biases them shut. In any case, the valve 5 members may have magnetic or compressible seals around their periphery that co-

operate with valve seats to seal respective ports.

In order that the invention can be more readily understood, reference will now be made, by way of example only, to the accompanying drawings in which: Figures l(a), l(b) and l(c) are a front elevation and two sectional views respectively of a cold-storage appliance of the invention; Figures 2(a), 2(b), and 2(c) are schematic sectional side views of a hinged-plate air 15 transfer valve for use in the appliance of Figures l(a), l(b) and l(c), in three modes of operation; Figures 3(a), 3(b), and 3(c) correspond to Figures 2(a), 2(b), and 2(c) but show a loose-plate air transfer valve in the same three modes of operation; and Figures 4(a), 4(b), and 4(c) correspond to Figures 2(a), 2(b), and 2(c) and Figures 3(a), 3(b), and 3(c) but show a diaphragm air transfer valve in the same three modes of operation.

25 Referring firstly to Figure l(a), this is a front elevation of a coldstorage appliance 332 that is functionally akin to the aforementioned Ewen prior art but addresses some of its

problems. In outward appearance, the appliance of Figure l(a) is a benchtype appliance having drawers 4, control panel 274 and refrigerator engine 272 under a worktop 270.

Figure l(b) - a section on line A-A of Figure l(a) - shows that each drawer 4 comprises a 30 lid 22 within the cabinet and a bin 16 movable forwardly from the cabinet on telescopic runners 74. Figure l(c) - a section on line B-B of Figure l(a) - shows those runners 74 beside the bin 16.

-5 Like Ewen, the bin 16 simply slides horizontally past the closefitting lid 22. The gap between the bin 16 and the lid 22 that is therefore necessary requires the creation of a complete external vapour barrier around the compartment that houses each drawer, so as 5 to overcome the associated moisture transmission and cross-contamination problems.

Thus, as Figure l(b) shows, the front panel 118 of each drawer extends beyond the corresponding drawer aperture defined between the lids 22 or between a lid 22 and a bottom panel 334. The overlapping portion of each front panel 118 has vertical magnetic seals 336 on its rear face that, when the drawer 4 is closed, seal by flexible resilience and 10 magnetic attraction against the opposed front faces of the lids 22 and/or the bottom panel 334 as appropriate. The drawer compartments are also sealed from each other; this applies especially to penetrations and service connections that run between neighbouring drawer compartments. It also applies to water drainage from the drawer compartments: separate drain lines (not shown) should be run individually from each compartment and should 15 each have in-line water traps.

Figure l(c) also shows L-section bin supports 338 depending from the runners 74 to cradle the bin 16 in a removable manner. Each drawer compartment should be of the minimum volume that allows access to the bin 16 and the associated runners 74.

Figures 2 to 4 show various air transfer valves that mitigate.the piston effect experienced when opening and closing a drawer 4 of the appliance 332 of Figures 1 (a), 1 (b) and 1 (c).

Figures 2(a), 3(a) and 4(a) show the status of the respective valves when the bin 16 is static, for example when the bin 16 is closed. Figures 2(b), 3(b) and 4(b) show the status 25 of the respective valves when the bin 16 is being opened, and Figures 2(c), 3(c) and 4(c) show the status of the respective valves when the bin 16 is being closed.

Dealing firstly with the features in common to all of the valves of Figures 2 to 4, they comprise an inlet duct 350 closable by an inlet valve member 352, an exhaust duct 354 30 closable by an exhaust valve member 356, and an intermediate duct 358 connected to the drawer compartment 344 that communicates with a central valve chamber 360 disposed between the valve members 352, 356. The inlet valve member 352 normally rests on an

-6 inlet valve seat 362 around a port 364 between the inlet duct 350 and the central valve chamber 360, and opens into the central chamber 360. Similarly, the exhaust valve member 356 normally rests on an exhaust valve seat 366 around a port 368 between the exhaust duct 354 and the central valve chamber 360, but the exhaust valve member 356 5 opens into the exhaust duct 354.

Both of the valve members 352, 356 are in their respective rest positions when the bin 16 is static, as Figures 2(a), 3(a) and 4(a) show. When the drawer 4 is being opened, however, air is drawn from the central valve chamber 360 toward the drawer compartment 344 as 10 shown in Figures 2(b), 3(b) and 4(b). The resulting low pressure in the central valve chamber 360 causes the inlet valve member 352 to open and admit air from the inlet duct 350 through the inlet port 364 into the central valve chamber 360 and from there into the drawer compartment 344. Conversely, when the drawer 4 is being closed, air is forced from the drawer compartment into the central valve chamber 360 as shown in Figures 2(c), 15 3(c) and 4(c), which increases the pressure in the central valve chamber 360 and so causes the exhaust valve member 356 to open. The air in the central valve chamber 360 thereby exhausts through the exhaust port 368 and out of the exhaust duct 354.

The inlet duct 350 draws ambient air from outside the cabinet of the appliance 332 and the 20 exhaust duct 354 similarly exhausts air to outside the cabinet. Thus, such air as is displaced by the piston action of the opening and closing drawer 4 does not travel between compartments 344 of the appliance 332 and so does not have a chance to cross contaminate between those compartments 344. It will be noted that in the passive or rest position shown in Figures 2(a), 3(a) and 4(a), the valves maintain the vapour barrier of the 25 cabinet. The valves and the inlet and exhaust ducts 350, 354 should be sized and located to minimise disturbance to the cold treated air in the bin 16 as the bin 16 experiences piston action upon opening and closing the associated drawer 4.

The differences between the valves of Figures 2 to 4 lie mainly in the valve members 30 and in their sealing arrangements with respect to their seats. The valve members 352, 356 in Figures 2 and 3 are rigid flaps or plates having magnetic or compressible seals 370 around their periphery that co-operate with the valve seats 362, 366 to seal the

-7 respective ports 364, 368. Both variants rely upon gravity and pressure differences to close the respective ports 364, 368. In Figure 2, the plates 352, 356 are hinged to one side so as to lift to the other side when they open their ports 364, 368. In Figure 3, however, the plates 352, 356 lie loosely on their seats 362, 366 and may be inclined as 5 shown to encourage one side to lift in favour of the other side when they open their ports 364, 368. In contrast, the valve members 352, 356 of Figure 4 are curved diaphragms whose curvature and resilience biases them shut, but which flex resiliently in response to pressure changes to open by flattening against the bias. It will also be evident from Figure 4 that the diaphragms 352, 356 have a flexible peripheral flange 372 that seals 10 against the valve seats 362,366. The diaphragm valve of Figure 4 has the benefit that its operation does not rely upon gravity to any extent; hence, the valve can be oriented in any way that may be desired.

Claims

-8 CLAIMS

1. A cold-storage appliance including: 5 at least one container; a structure defining a vapour-sealable container compartment from which the container can be withdrawn to open the container and afford access to its interior and to which the container can be returned to close the container for cold storage of any items 10 within the container, and valve means communicating with the container compartment to admit air from outside the appliance when the container is being withdrawn from the container compartment, to expel air outside the appliance when the container is being returned to the 15 container compartment, and to maintain a vapour seal with the container compartment when the container is within the container compartment.

2. The appliance of Claim 1, wherein the valve means comprises an inlet duct closable

by an inlet valve member, an exhaust duct closable by an exhaust valve member, and an 20 intermediate duct connected to the container compartment that communicates with a central valve chamber disposed between the inlet valve member and the exhaust valve member.

3. The appliance of Claim 2, wherein the inlet valve member normally rests on an inlet 25 valve seat around a port between the inlet duct and the central valve chamber, and opens into the central valve chamber.

4. The appliance of Claim 2 or Claim 3, wherein the exhaust valve member normally rests on an exhaust valve seat around a port between the exhaust duct and the central 30 valve chamber, and opens into the exhaust duct.

5. The appliance of any of Claims 2 to 4, wherein the inlet valve member and the

-9- exhaust valve member are in their respective rest positions when the container is static.

6. The appliance of any of Claims 2 to 5, wherein when the container is being opened, the inlet valve member opens and admits air from the inlet duct to flow into the 5 container compartment.

7. The appliance of any of Claims 2 to 6, wherein when the container is being closed, air forced from the container compartment causes the exhaust valve member to open and is exhausted out of the exhaust duct.

8. The appliance of any of Claims 2 to 7, wherein the inlet duct draws ambient air from outside the appliance and the exhaust duct exhausts air to outside the appliance.

9. The appliance of any of Claims 2 to 8, wherein the valve members are rigid flaps or 1 5 plates.

10. The appliance of any of Claims 2 to 9, wherein the valve members rely upon gravity and pressure differences to close.

20

11. The appliance of any of Claims 2 to lO, wherein the valve members are resilient curved diaphragms whose resilience and curvature biases them shut.

12. The appliance of any of Claims 2 to 11, wherein the valve members have magnetic or compressible seals around their periphery that co- operate with valve seats to seal 25 respective ports.

13. A cold-storage appliance, substantially as hereinbefore described with reference to or as illustrated in any of Figures 2(a) to 4(c) of the accompanying drawings.