HEAT INSULATING WALL PANEL, PARTICULARLY FOR WALLS OF GOODS CONTAINERS

Abstract: Heat insulating wall panel intended in particular as a wall material in a goods container, intended for refrigerator transports or for transports where the goods should be protected from low outside temperatures, and which wall panel consists of a core applied and fixed between two surface materials (4), said core consisting of elements of two different expanding thermoplastics, in particular expanded polyvinyl chloride and expanded polystyrene, whereby the core comprises a bottom beam (1) of expanded polyvinyl chloride, two end elements (2) of expanded polystyrene of high density standing on this bottom beam, and elements (3) of expanded polystyrene of low density standing on the bottom beam and filling the space between the end elements (3).

Description: HEAT INSULATING WALL PANEL, PARTICULARLY FOR WALLS OF GOODS CONTAINERS The present invention refers to a heat insulating wall panel intended in particular as a wall material in a goods contai¬ ner, intended for refrigerator transports or for transports where the goods should be protected from low outside tempe¬ ratures, and which wall panel consists of a core applied and fixed between two surface materials, said core consisting of elements of two different expanding thermoplastics, in particular expanded polyvinyl chloride and expanded polysty¬ rene. For such purposes a material is needed, which gives a good heat insulation, which has no tendency to absorb moisture, which is relatively light, which has sufficient strength to stand high loads, and in particular edge loads, which may amount to high values when several goods containers are piled on each other. Further it is a requirement that the material should be as cheap as possible. To fulfil these requirements plastic material has been used, which in the form of panels have been placed between two cover layers, which may be sheet metal, aluminium, plastics or the like, which are glued together with known technique. One plastic material which for this purpose has shown to fulfil most of these requirements is expanded rjolyvinyl chloride PVC, which is however relatively expensive. Another plastic material which has been used with a good result is expanded polystyrene, which however has far too low strength to withstand the mechanical edge pressures, the material will be subjected to in an application to a goods container. Previously has been suggested a heat insulating panel (GB-A 2 210 396) constructed from two external hard panels, which surround two insulating expanding thermoplastics, of which one forms a frame around the other with lower density, and where the hard panels are glued to the insulating layers, and the edge lists forming the frame thereby are made in expanded polyvinyl chloride and the insulating layer pro- vided in the frame is constituted by expanded polystyrene. In this way a panel has been provided a panel which fulfils the requirements made, which however after all is relatively costly by the not insignificant amount of polyvinyl chloride which is required for the frame. The object of the present invention is to provide a heat insulating wall panel, which has at least equally good properties as the previously proposed panel with a PVC- frame around an internal insulation of a quality of expanded polystyrene, and which moreover is substantially less ex¬ pensive than this. For this object is proposed a wall panel of a design shown in the accompanying drawing of which in Fig. 1 the wall panel is illustrated without the steel plates, which are to surround the isolating material, while the wall panel in Fig. 2 is shown with plates, which however are partly cut away. The wall panel according to the invention consists of a bottom beam of polyvinylchloride 1, and on this bottom beam most adjacent to the end edges are provided two standing end elements 2, which consist of expanded polystyrene with high density, e.g. manufactured by DOW chemical with the designa¬ tion Styrofoam HD300. Between the two end elements 2 are then provided a number of elements 3 , which likewise con¬ sist of expanded polystyrene, but of a lower density , e.g. Dow styrofoam RTM. Both these insulating materials are substantially less expensive than expanded polyvinyl chlori¬ de and Styrofoam HD300 and moreover has a strength, which is comparable with that of the frame made of PVC. The bottom beam of expanded PVC absorbs loads in the bottom structure when lifting with fork truck or the like, while the polystyrene with high density has tensile properties enough to stand all normally occurring loads in the remai- ning parts of the wall structure. In Fig. 2 is shown how the insulating part av the wall element illustrated in Fig. 1, consisting of a PVC -bottom beam and two different densities of expanded polystyrene, on both flat side surfaces is provided with on thereto applied hard surface materials, preferably steel plates, which are glued to the inside situated insulating layers. For the end elements 2 of expanded polystyrene, qualities of polystyrene with a density of 45 kg/m 3 can be used, while for the intermediate polystyrene elements 3 e.g. can be chosen a density of e.g. 40 kg/m 3 . By utilizing two different densities of the comparably cheap material expanded polystyrene arranged on a bottom beam of the more expensive material expanded polyvinyl chloride, has been provided a wall element to a substantially lower price with insulating properties and strength corresponding to those of the above mentioned polystyrene panel with a frame of expensive polyvinyl chloride surrounding the whole panel. As an alternative to the design described above and illu¬ strated in the drawings of wall elements according to the invention it is possible to use a solid thin frame of ex- panded polystyrene with high density while the inner ele¬ ments are constituted by expanded polystyrene with lower density.

Claims: CLAIMS 1. Heat insulating wall panel intended in particular as a wall material in a goods container, intended for refrigera- tor transports or for transports where the goods should be protected from low outside temperatures, and which wall panel consists of a core applied and fixed between two surface materials (4), said core consisting of elements of two different expanding thermoplastics, in particular ex- panded polyvinyl chloride and expanded polystyrene, c h a r a c t e r i z e d t h e r e i n, that the core comprises a bottom beam (1) of expanded poly¬ vinyl chloride, two end elements (2) of expanded polystyrene of high density standing on this bottom beam, and elements (3) of expanded polystyrene of low density standing on the bottom beam and filling the space between the end elements (3). 2. Heat insulating wall panel intended in particular as a wall material in a goods container, intended for refrigera¬ tor transports or for transports where the goods should be protected from low outside temperatures, and which wall panel consists of a core applied and fixed between two surface materials (4), consisting of a thin frame and in this provided elements of expanded thermoplastics, c h a r a c t e r i z e d t h e r e i , that the frame is constituted by an expanded polystyrene of high density, and the elements filling the frame consist of expanded polystyrene of low density.

Inventors: LILJEGREN PETER, LILJEGREN, PETER
Applicants: LILJEGREN PETER, LILJEGREN, PETER
Application year: 1990
Main classification: E04B1
IPC codes: B65D90, E04C2, F25D23