Transport container
This invention relates to a transport container especially but not exclusively intended for air freight and comprising a closed unit provided with one or more doors or the like and an internal cooling space. In connection with air freight of transport containers it is previously known to use closed units provided with an outer casing of preferably glassfibre with so-called self- -circulation, cooling of the intended goods being obtained by using dry ice developing gases which are passed through the very container. However, the gases, preferably carbonic acid, are a security risk both for the very goods in the containers and for the passengers in the aircraft. For this reason it is normally not permitted to transport more than two containers per aircraft. However, the carbonic acid gas has always a certain tendency to influence living products, e.g. vegetable foodstuffs in the form of green plants or animal foodstuffs in the form of e.g. crabs, in a negative direction. This means that said food products can be subjected to non-desired colour changes . Cooling containers based on cooling by the aid of dry ice, which, in addition, requires much space, have also always a limited cooling ability which is an essential disadvantage and may per se also involve great operational problems. Thus, only a limited amount of dry ice can of course be brought alon and obviously unintentinal transport pauses in the form of stops on airports or the like may considerably prolong the transport time calculated from the beginning, so that the whole store of dry ice is consumed and the contents of the container run the risk of being destroyed. It is the object of the invention to eliminate the dis¬ advantages mentioned above in connection with known transport containers intended for air freight. The construction of the new container must be light, simultaneously as the container must be well *insulated and essentially have no cold bridges. Thus, there must be no direct contact between the in- and out¬ side of the new unit. Moreover, the insulation of the container should be very little moisture-absorbing simultaneously as its outer covering layer should have a smooth surface easy to
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clean. Of course there should be a possibility of a simple cleaning of the inside of the container, and its interior surfaces should therefore also be smooth although they may possibly be corrugated. The intended purpose of the invention is achieved in that the transport container defined in the introductory section consists of a unit built of a insulating sandwich construction with a cooler unit mounted therein, which is arranged with current supply by one or more associated rechargeable batteries. It must be possible to supply current not only from said batteries but also directly from an arbitrary outer current source. By designing and arranging the transport container in this way it will be possible to carry through "from-door-to-door" transports without breaking or risking to break the continuous cooling line of the transported goods.
Thus, the goods to be transported can e.g. be loaded into the container when this is accomodated in some form of cooling space, after which the container is closed and stowed onto a truck. During truck transport to e.g. an airport the cooler unit of the transport container is fed with current from the separate current supply source of the car or, as an alternative from the built-in batteries. On the air terminal current is supplied by the electric mains there, e.g. a conventional one of 220 or 100 V. After stowing the container into the cargo space of the aircraft the charged batteries - preferably
24 V - are connected, or else the current supply, whenever applicable, can take place via the internal current supply source of the aircraft. The cooler unit is then fed with current in the same or similar way from the terminal of delivery to the customer, also, by the associated batteries, the conventional mains or local current supply sources. The invention will now be described in a preferred illustrative example with reference to the enclosed drawing. Fig. 1 is a top plan view from one short side of a trans- port container embodied according to the principles of the invention.
Fig. 2 is a front plan view of the transport container illustrated in Fig. 1.
Fig. 5 is a top plan view of the new transport container, the roof portion of the container being removed to illustrate
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its interior.
Fig. 4 schematically shows the main portions included in the cooler unit of the new transport container.
The transport container illustrated in Figs. 1-3 consists of a closed unit 12 provided with an internal cooling space 10, said unit being built for an insulating sandwich construction in the form of a core 14 consisting of a DIVINYCELL material, which is surrounded on both sides by a protective covering layer 16 and 18, respectively. The DIVINYCELL material consists of light cellular plastic i.e. expanded plastic with closed cells, and has a very low density. The expanded plastic material is based on polyvinyl having properties which are especially suited for use for the intended purpose such as load-carrying core material in a sandwich construction. The material has a low water absorption ability and a good ability of standing heavy loads. Besides, it is resistent to many chemicals and, moreover, selfquenching which is particularly advantageous when used in aircrafts. The protective covering layers 16, 18 applied upon the core material 14 are bonded to the core material by means of an adhesive especially intended for the purpose. The covering layers 16, 18 advantageously consists of light aluminum plates. This gives a transport container of a very low total weight . In the embodiment shown on the drawing the walls 20, the roof 22, the bottom 24 and the door 26 of the cooling space are internally corrugated which contributes to increasing spreading of cooling air passing through the cooling space 10. Moreover, the in- and outsides of the construction are smooth which makes it easy to clean the container, as already mentioned by way of introduction.
One long side of the transport container on the whole consists of the light double door 26 adjustable in conventional manner by means of rail 28 and control handle 30 and resting on hinges 52 of a construction also known per se. Between the two halves of the door 52 as well as at its outer edges against the short sides of the container there are sealing jointings 34 ensuring a good insulation when the door is closed.
The cooler unit 56 associated with the new transport container can be embodied and placed in many different ways.
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What is essential in this connection is that said unit 36 is arranged for current supply via one or more associated re¬ chargeable batteries 38. Moreover, a battery charger as well as battery eliminator not shown on the drawing belong to the unit which can also be fed with current from an outer current soruce, e.g. the conventional mains at 220 or 110 V.
As is apparent from the drawing the cooler aggregate 56 projects into the transport container at one of its upper corners, the unit being accessible via a cover plate made as a door 10. In Figs. 1-5 the transport container is shown in resting position on a pallet bottom 42.
As appears from Fig. 4 the cooler unit belonging to the transport container comprises an internal voltage source, preferably with the voltage 24 V, in the form of four battery units 38, which are connectible, as desired, in parallel or in series, to drive the electric devices of the cooler unit. The cooler unit is of compressor type and, thus, comprises a compressor 44 as well as a condenser 46 connected thereto. A first fan device 4S is associated with the condenser 46 and a second fan device 50 is associated with the evaporator 52 in the very cooling space 10. A throttle valve 54 and a filter 56 are arranged in the line 58 between the evaporator 52 and the condenser 46 in conventional manner. Moreover, in the cooling space there is a thermostat 60 for control of the temperature within the desired temperature range.
Modifications of the transport container described above can be made within the scope of the invention. The container form, in particular, may vary within w-ide limits for adaption to the form of various storage spaces.