METHOD FOR PRODUCING WALL, WALL DEVICE OR ELEMENT FOR COLD STORAGE SPACES AND DEVICE MADE ACCORDING TO THE METHOD

Abstract: This invention relates to a method for producing a wall, wall device of wall element for containers, boxes and the like, including outer sheets of panes defining the exterior and between them defining chamber means for water or the like phase changing material. The novelty lies in joining an outer and an inner sheet or pane (1 and 2) so that they together define a chamber (4), to provide such chamber with a permanently closable opening (5) and to allow an outer force (T) in a pressing together direction act against at least one of the sheets or panes thereby reducing the volume of the chamber approximately 10 % and make liquid introduced into the chamber completely fill the thus reduced volume and in the pressed together state permanently close the opening. The invention also relates to a device made according to the method, wherein at least one side sheet or pane can be inwardly buckled from a rest position to a position reducing the chamber volume between the side sheets or panes.

Description: Method for producing wall, wall device or element for cold storage spaces and device made according to the method. Technical Field of the Invention Products sensitive to temperature, such as fresh food, other heat sensitive products and medicines and pharmaceutical products are today - as long as it concerns larger quantities - transported in vehicles large containers and the like provided with apparatuses for keeping the inside temperature at an intended level. Large volumes and long transports motivate the use of such vehicles or container and there a few problems connected with the keeping of the temperature on intended levels. On transporting small volumes - e.g. to retailers or end users - problems often occur concerning the keeping the temperature level also when properly insulated containers or boxes are used. In order to guarantee that correct temperature is kept containers of which at least the walls include "chargeable" cooling elements, e.g. spaces filled with water or similar phase changing material (PCM) are frequently used. Such cooling elements are charged by placing the container part including such elements, in some cases the entire container, inside a space where they are exposed to cold , i.e. placed in a cool place so that the water is transformed to ice and another phase changing material congeals, respectively. Such a charging procedure results in a defined duration as long as the time necessary for transforming the ice to water/the congealed PCM to liquid phase. Background of the Invention On manufacturing elements or devices or parts intended to contain water or other PCM one seeks to minimize the weight of the material as much as possible, i.e. to make the water containing walls as thin, and accordingly as light as possible. It has then to be considered that the transformation from liquid to solid phase and the other way round results in a change of volume in the range of about 10%. This means that the full volume of a chamber or space can be filled only up to 90% of the liquid phase without risking a breaking or bursting on a later transformation to solid phase. At walls of rigid materials and including one or more chambers has up till now , in order to compensate for the increase of volume on the phase transformation only been filled up to 90% of the available volume only, hoping that on the increase of volume the free space be filled with congealed material. The expansion on the phase transformation however takes place essentially in a direction perpendicular to enclosing walls, which means that a space at the upper portion of the wall remains unoccupied also after the transformation into solid phase. The corresponding portion of the wall thereby not only will lack cooling ability but also serves a heat passage. The wall portion adjacent to the empty space thus will serve as a heat passage towards to surroundings and will reduce the cooling effect totally. In order to solve the problem with lack of cooling effect especially at the upper portions of walls and like provided with coolant substance containing chambers it is earlier suggested to fill such chambers with a multitude of hose or bladder shaped units filled with water, brine of other PCM. Such units which are made of elastic material, can be completely filled with liquid PCM as they on the phase changing and the expansion are able to expand into small free spaces between them. Such kinds of wall or panel arrangements for cool containers are however expensive in production, have short life length and have not gained any mentionable market. One object of the invention is to bring about method for producing a simple, inexpensive, mechanically strong and easy to maintain wall, wall arrangement or wall intended to be included in or form panels or walls or spacers for containers, boxes and the like for temperature sensitive goods and arranged to safeguard a reliable temperature control over its entire surface, i.e. the entire volume of the container. Summary of the Invention The new method according to the invention lies in providing a wall device having a thickness being small relatively to its width and height and including two side panes arranged at a distance from each other and at least along its outer edges liquid and gas tight joined to each other in order to form a least one chamber and having a permanently closable filling opening, introducing through said opening into said chamber water or other PTM in liquid phase is filled, wherein in a preferred embodiment where the volume of the chamber is known, a water or liquid volume corresponding to 90% of the chamber volume is introduced. After that a mechanical pressure is allowed to act towards the side panes of the chamber unit, resulting in a reduction of the chamber volume so much that the level of the water or liquid introduced reaches the filling opening, upon which the opening is closed and sealed. Alternatively the chamber volume initially can be completely filled whereupon a pressure is allowed to act the side panes until a water or liquid volume corresponding to 10 % of the total volume is ejected. Finally the opening is closed and sealed. By closing and sealing the opening no air can enter the chamber resulting in that the side panes or at least one of them will be slightly inwardly buckled, said shape remaining as long as the water or liquid temperature remains above the congealing point of the water or liquid. On freezing or congealing a expansion of the volume will occur and the panes enclosing the chamber will pressed outwardly to the position before the inwardly pressing. The new wall element presents at least one slightly inwardly buckled side sheet or pane or the like as long as the water or liquid is in liquid shape and that such pane or the like after a phase change has occurred, thanks to the expansion resulting thereof returned to an essentially plane shape, i.e. the shape appearing before the pressing operation. Brief Description of the Drawings The invention will be described in details in the following with references to the drawing attached hereto wherein, Fig.1 schematically shows a section of a wall element according to the invention after it has been filled with water or liquid, Fig. 2 shows the same section and how a mechanical pressure is acting against it sees and how the filling opening is closed and Fig. 3 shows the same section after phase change i.e. the water or liquid has frozen or congealed respectively. Detailed Description of Preferred Embodiment A wall device according to the invention of the kind shown on the drawing can be adapted to form or be part of a wall of a container, the other walls as well as bottom and lid of which also being similar wall devices. The device can also be one of six or more similar devices intended to form below, around and above an object put into a container a cooling cover means. The precise shape thus may vary. In the common case the device will be shaped as a rather thin panel or wall element, which can be detachably or permanently arranged at container or even constitute the very wall of the container. The device shown on the drawing essentially includes two oppositely arranged relatively thin sheets or panels 1 and 2 of aluminium, stainless steel, plastic material or the like. The sheets or panels are along their edges 3 tightly joined, e.g. by welding or lapping to that a tight joint is formed. The edge portions of the sheets or panes normally are slightly bent toward each other so that the major areas thereof will be at a distance from each other and a chamber 4 is created between them. At the upper edge of the wall of the device there is a permanently closable opening 5, through which water or other liquid can be introduced. According to the preferred method, it is essential to, before introducing water, find out the exact volume of the chamber 4 of the device. A volume water or other phase changing liquid corresponding to 90%o of the total chamber volume is then filed into the chamber. After that and with the opening 5 still open, a pressure force T is made to bias the panes or sheets 1 and 2 of the device so that at least one of them is slightly inwardly buckled . This results in a reduction of the chamber volume and that the water or liquid level will raise so that the chamber is filled all the way to the opening. Keeping the pressure against the sides the opening is closed and sealed. The device is now ready for use. According to an alternative method water or the like is filled into the chamber volume defined by the sheets or panes 1 and 2 until it is completely filled, the volume filled is subsequently noted. By pressing together the panes or sheets so that the volume of the chamber is reduced, a quantity water or liquid corresponding to 10%> of the total volume is ejected, that is a quantity of water or liquid corresponding to the expected volume expansion or freezing or congealing. Finally the opening 5 is closed and sealed and the device is ready for use. The filled and sealed wall device will as long as the water or the like is in liquid state have slightly inwardly buckled sides. When the device is exposed to cold below the freezing or congealing point, an expansion occurs resulting in a return of the walls to their original shape, i.e. their shape before the pressing together. Due to the fact that the interior volume of the device is permanently filled with water or liquid alternatively ice or congealed liquid, there will appear no heat transmitting areas at any edge.

Claims: Claims 1. Method for producing a wall device, wall element or wall intended for containers, boxes or the like arranged for the transport of cold or freeze transport, the wall device including outer sheets or panes defining the exterior thereof and a chamber means for water or the like phase changing material c h a r a c t e r i z e d by joining an inner and an outer sheet or pane (1 and 2) for the device so that they together define a chamber (4) having a cross width being small compared with its length and height, providing a permanently closable opening (5) at the chamber, adapting the volume of water or the like liquid relatively to the total chamber volume so that it in the initial and open state fills approximately 90% of the available chamber volume, allowing a force (T) to essentially perpendicularly bias at least one of the chamber defining sheets or panes (1, 2) in order to reduce the chamber volume with approximately 10 % , i.e. a reduction of volume corresponding to the expansion of volume on freezing or congealing, respectively, so that the water or liquid inside the chamber completely occupies the reduced chamber volume and in the pressed together state permanently closing and sealing the opening (5). 2. Method according to claim ^ c h a r ac t e r i z e d in introducing into the chamber a quantity of water or other phase changing material in liquid state occupying approximately 90% of the chamber (4) and before closing of the opening (5) press the at least one of the sheets or panes (1, 2) thereby reducing he inside volume so that the water or liquid level reaches the filling opening (5). 3. Method according to claim 1, c h a r a c t e r i z e d in introducing into the chamber (4) an adapted volume of water or phase changing material in liquid state all the way up to the filing opening (5) and before the closing of the opening press the device together so that approximately 10%o of the water or liquid is ejected. 4. Wall device, wall or wall element for containers, boxes or the like units adapted for cold or freeze transport including inner and outer sheets or panes (1, 2) defining between them chamber means (4) for phase changing material such as water c h a r a c t e r i z e d in that at least one of the inner or outer sheets or panes (1, 2), which define the chamber for receiving phase changing material, is flexible and on being pressed from the outside able to buckle inwardly, so that in the inwardly buckled state the two sheets or panes together define a chamber volume in the range of 90% of the volume thereof in the unbiased state of the sheets, and in that quantity of phase changing material introduced corresponds to the volume defined by the inwardly buckled inner and outer sheets or panes , whereas the chamber volume in the state of the sheets or panes unbiased by outer pressure corresponds to the volume of the phase changing material in its solid or congealed phase.

Inventors: BRUCE HANS, BRUCE, HANS
Applicants: BRUCE HANS, BRUCE, HANS
Application year: 2001
Main classification: B65D81
IPC codes: F25D3, F25D23, F28D20