GB2529753A

GB2529753A - Heated door

Info

Publication number: GB2529753A
Application number: GB1511202.2A
Authority: GB
Inventors: Ian Mark Throp
Original assignee: Ralph Ellerker 1795 Ltd
Current assignee: Ralph Ellerker 1795 Ltd
Priority date: 2014-06-26
Filing date: 2015-06-25
Publication date: 2016-03-02
Also published as: GB201511202D0; GB201411367D0

Abstract

A door system 10 for closing an aperture between spaces at different temperatures comprises a door member 12 of flexible fabric moveable between an open (fig 2) and closed configuration, and comprises an electrical heated element 22 used to heat the door. The door system may comprise left and right upright frame members 14a, 14b, an overhead hood / frame member 16 and a motor 18 to roll the door up and down. The door system closes a hatch 20 and the heated element is coextensive with the hatch. The heated element may be a printed metallic or graphene pad, mat or panel embedded within the door between at least two skins and located in a lower portion of the door. When raised an upper portion of the door becomes wound on a roller inside the overhead hood / frame member and when above the hatch leaves the hatch completely open. When raised the lower portion of the door 12 containing the heated element remains flat and is not rolled up. An insulating member (28, fig 5) may be embedded in the door. The door may be used in refrigerated stores and prevent ice forming on the door.

Description

Heated Door The present invention relates to a heated door, and is concerned particularly, although not exclusively, with a heated door for closing a hatchway of a refrigerated store.

Thermally insulated doors are used in various environments where a temperature differential must be maintained between two spaces, despite access being required between the spaces. Such doors are used, for example, at the entrance to refrigerated storerooms. When the door is opened, typically by raising it, moisture-laden air from outside the storeroom can come into contact with the much lower temperature of the storeroom and ice can form on the cold surfaces of the door and frame.

Our United Kingdom Patent, Number GB 2 385 659 B, the entire conLents of which are incorporated herein by reference, describes one such door system, comprising a double-skinned flexible fabric door mounted in a frame.

Conditioned air is directed through cavities in the uprights of the frame, inLo a gap beLween the two skins of the door and back to an overhead hood, in a closed loop.

The conditioned air Is heated arid de-ht]rn.i.dif.i ed so as to minimise the risk of condensation forming on the interior surfaces of the door skins and inside the frame members, and also of frost and ice forming on the frame surfaces facing inwardly and exposed to the refrigerated room, and the door skin facing the moisture-laden air outside the refrigerated room.

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The door is raised or lowered, respectively to open or close the doorway into the refrigerated space. When the door is raised the two skins roll up around rollers located above the door. The above-described door system is an effective solution to the problem of ice and frost building up on the cold side of the door due to the repeated ingress of relatively humid air when the door is opened.

However, the abovementioned type of door is suited mainly to relatively large openings, such as major doorways through which personnel and even vehicles pass. Because of its bulk, its mass and its level of sophistication it is not ideal for smaller openings, such as hatchways through which conveyors pass. These are typically much smaller, and can often be found high up on a wall of a warehouse, for

example.

Accordingly, embodiments of the present invention aim to provide a door system of relatively simple design that addresses at least some of the abovementjoned drawbacks of the previously considered systems.

The present invention is defined in the atLached independent claims, to which reference should now be made.

Further, preferred features may be found in the sub-claims appended thereto.

According to one aspecL of the present invention, there is provided a door system for closing an aperture between spaces at different temperatures, Lhe door system comprising a door member moveable between a closed configuration in which it substantially closes the aperture, and an open configuration in which the aperture is substantially open, wherein the door member comprises an electrically operable heater element arranged in use to heat the door member.

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The heater element is preferably located in a first portion of the door meraber.

Preferably the heater element is in the form of a pad, mat or panel.

The first portion of the door member may be relatively rigid. The door member may have a second portion LhaL is relatively flexible.

In a preferred arrangement the heater element is embedded within the door member.

The door member may comprise at least two skins or layers.

Tn a preferred arrangement the heater element is located beLween the skins.

Alternatively, Lhe heater element may be affixed to an outward-facing surface of the door skin, such as a surface of the door skin Lacing a higher temperature space.

The door member may be arranged to be at least partly rolled up when in the open configuration. In a preferred arrangement the second portion of the door member is arranged to be rolled up, and the IirsL portion of the door member is arranged to remain substantially flat, when the door member is in the open configuration.

The door member preferably includes an insulating member.

Preferably the insulating member is embedded in the door member. In a preferred arrangement, the insulating member is located closer to a side of the door member that is arranged in use to face a lower temperature space.

Preferably the heater element is located closer to a s-ide of the door member thaL is arranged in use to face a higher temperature space.

Alternatively, or in addition, the heater element may be in the form of an electrically conductive layer located in or on the door member. The electrically conductive layer may comprise a track, strip or pattern of electrically conductive material, which may be metallic or may comprise graphene for example. The conductive layer may be applied directly to the door member, and may comprise a printed layer.

In another aspect the invention comprises a method of heating a door member in a door system for closing an aperture between spaces at different temperatures, the door system comprising a door member moveable between a closed configuration in which it substantially closes the aperture, and an open configuration in which the aperture is substantially open, the door member comprising an electrically operable heater element arranged.. use to heat the door member, wherein the method comprises applying an electrical current to the heater element causing the heater element to experience resistive heating, and to heat the door member by thermal conduction.

The invention may include any combination of the features or limitations referred to herein, except such a combination of features as are mutually exclusive, or mutually inconsistent.

A preferred embodiment of the present invention will now be described. By way of example only, with reference to the accompanying diagrammatic drawings, in which: Figure 1 shows schematically, in front view, a door system according to an embodiment of the present invention1 in a first, closed configuration; Figure 2 shows schematically, in front view, the door system of Figure 1 in a second, open configuration; Figure 3 is a schematic side view of Lhe door system of Figures 1 and 2; Figure 4 is a schematic plan view of part of the door system of Figures 1 to 3; and Figure 5 is a part-sectional view of a part of the door of Figures 1 to 4.

Turning to Figure 1, this shows, generally at 10, an electromechanical door system according to a preferred embodiment of the present invention. The door system 10 comprises a door member, or door leaf 12, of flexible fabric, left and right upright frame members 14a and 14b, overhead hood/frame member 16 and a motor 18.

In Figure 1, the door is in a closed configuration, in which it closes a hatch 20, shown in dotted lines behind the door leaf 12. A lower portion of the door leaf 12 has embedded within it an electrically operated heater pad, comprising a heater element. The electrical heater pad is substantially co-extensive with the hatch 20, and is represented by the broken lines at 22.

The door can be operated automatically by one or more of a variety of activators and sensors such as, but not limited to: a photo-cell., pressure pad, light sensor, to suit the specific application and site conditions Lhrough an operation console 24 located adjacent the door where practicable, or else located remotely if necessary. The operation console can be used to manually operate the door.

When the door is raised, an upper portion of the door leaf 12 becomes wound up on a roller inside the hood/overhead frame member, as shown in Figure 2. In this configuration, the door leaf 12, incorporating the heater pad 22, becomes raised above the hatch 20, leaving it completely open. The lower portion of the door 12 containing the pad 22 remains flat and is not rolled up inside the hood/frame member 16.

In use the hatch 20 connects a refrigerated space with a non-refrigerated space, and the door 12 is usually kept closed when access is not needed, so as to help maintain the temperature differential.

The warmer air from the ambient, or non-refrigerated, side typically has a higher moisLure content than the cooler air inside the refrigerated space, and condensation tends to form on the warmer, ambient-facing side of the door, quickly forming frost and ice. To combat this, the heater pad 22 warms the ambient-facing side of the door 12.

Figure 3 shows the door in side view.

Figure 4 is a plan view of part of the door system shown in Figures 1 to 3. The door 12 itself comprises a pair of skins 12a and 12b sandwiching the heater pad 22 therebetween, and edge connectors 26 that are retained in the upright fj..ame members j..

Figure 5 is a more detailed, and part-sectional, view of part of the door system shown in Figure 4. In this drawing the heater pad 22 can be seen sandwiched between the skins 12a and 12b of the door 12. The heater pad is adhered to the skin 12a that faces the ambient-temperature air, ie the heater pad is located closer to the skin that faces away from the refrigerated side of the hatch. An insulating pad 28, of composite material, is located between the heater pad 22 and the skin 12b that faces the refrigerated side of the door.

The door system described above has been developed specifically for very small conveyor openings into cold stores from chilled or ambient-temperature areas where condensation can form on the fabric skins of the door blade between the two areas, due to differences in temperature and humidity levels.

typically sizes for the conveyor openings range from 300mm x 300mm up to a maximum of 1.5m x l.5m and can be at ground level or high level. The small size and locations of these openings make it impractical to install a typical freezer door such as referred to above in relation to our UK Patenb Number GB 2 385 659 B, which may often be considered to be too heavy, bulky, unnecessarily sophisticated and expensive for the openings in question.

The door is of a typical hi-speed design concept having a support frame 14, 16 with integral door skin side guides, a top roll assembly powered by an electric geared motor unit 18 that collects and dispels the door skin during opening and closing; and with various safety device options.

The part of the door 12 that covers the aperture 20 in the closed position has a low voltage encapsulated rigid heating element pad 22 within. The element, which may comprise a mesh or plural loops of wire, in a generally planar arrangement, is sandwiched between door skins 12a and l2b and is adhered to the door sktn l2a facing the side with the greaLer air temperature in use. The Lwo door skins 12a and l2b are high-frequency welded together to form one thickness at the leg side guide location. The rigid heating element pad 22 can be designed to be temperature-controlled or of a fixed temperature type. A Lhermal overload is provided to protect the integrity of the heating wires at a temperature suitable for the chosen heating element. Mains electrical power is supplied through wiring (not shown) The door height is designed in such a way that when the door member 12 is raised to reveal the aperture 20, the rigid heated clement pad 22 stops just prior to the top roll 16. This ensures that damage to the heated element

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does not occur by bending the embedded heating wires within around the top roll. The door skin material is manufactured from a fire retardant material to increase the safety of the door.

The door is suitable where ample headroom is available as the complete door assembly is in excess of twice the aperture height.

In an alternative embodiment of the present invention (not shown) the door member has an electrically conductive layer, in the form of a track or pattern applied directly to the door skin. The layer is preferably applied to the side of the door member facing the ambient-temperature side or non-refrigerated side. The layer may he metallic, or may be of a material such as graphene, for example, and may be printed onto the door skin. When connected to an electrical power supply, the Jayer experienced resistive heating. The heat generated passes to the door by [thermal conduction.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance, it should be understood that the applicant claims protection in respect of any patentable feature or combination of features referred to herein, and/or shown in Lhe drawings, whether or not particular emphasis has been placed thereon.

Claims

CLAIMS1. A door system for closing an aperture between spaces at different temperatures, the door system comprising a door member moveable between a closed configuration in which it substantially closes the aperture, and an open configuration in which the aperture is substantially open, wherein the door member comprises an electricajjy operable heater element arranged in use to heat the door member.
2. A door system according to Claim 1, wherein the heater element is in the form of a pad, mat or panel.
3. A door system according to Claim 1 or claim 2, wherein the heater element is located in a first, relatively rigid, portion of the door member and the door member has a second portion that is relatively flexible.

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4. A door system according to any of claims 1 to 3, wherein the heater element is embedded within the door member.
5. A door system accordtng to any of Claims 1 to 4, wherein the door member comprises at least two skins or layers.
6. A door system according to claim 5, wherein the heater clement is located between the skins.
7. A door system according to any of the preceding claims, wherein the door member is arranged to be rolled up when in the open configuration.
8. A door system according to Claims 3 and 7, wherein the second portion of the door member is arranged to be rolled up, and the first portion of the door member is arranged to remain substantially flat, when the door member is in the open configuration.
9. A door system according to any of the preceding claims, wherein the door member includes an insulating member.
10. A door system according to Claim 9, wherein the insulating member is embedded in the door member.
11. A door system according to Claim 9 or 10, wherein the insulating member is located closer to a side of the door member that is arranged in use to face a lower temperature space.
12. A door system according to any of the preceding claims, whcrein the heater element is located closer to a side of the door member that is arranged in use to face a higher temperature space.
13. A door system according to Claim 1, wherein the heater element comprises an electrically conductive layer located in or on the door member.
14. A door sysLem according to Claim 13, wherein the electrically conductive layer comprises a track, strip or paLLern of e].ectricelly conductive material. ii
15. A door system according to Claim 13 or 14, wherein the layer is of metallic material or of graphene.
16. A door system according bo any of Claims 13 to 15 wherein the conductive layer is applied directly to the door member.
17. A door system according to any of Claims 13 to 16, wherein the conductive layer comprises a printed layer.
18. A method of heating a door member in a door system for closing an aperture between spaces at differenL temperatures, the door system comprising a door member moveable bcbwraon a closed configuration in which it substantially closes the aperture, and an open configuration in which the aperture is substantially open, the door member comprising an electrically operable heater element arranged in use to heat the door member, wherein the method comprises applying an electrical current to the heater element causing the heater element to experience resistive heating, and to heat the door member by thermal conduction.
19. A door system substantially as herein described with reference to the accompanying drawings.
20. A method of heating a door member1 the method being substantially as herein described, with reference to the accompanying drawings.