Abstract:
Inside a steel container ( 1, 17, 23 ), a bin ( 3 ) of corrosion-resistant material is fitted. This bin ( 3 ) is fastened to the container walls. The side walls and the top wall of the bin are substantially identical in shape to those of the steel container. The container is intended for the transport of bulk goods, especially plastics particle material, the contamination of this material by steel particles, which have come loose as a result of corrosion, being prevented.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a steel container, especially intended for the storage and transport of bulk goods, the inner surfaces of the container being covered by walls made of corrosion-resistant material, which walls together form a closed box, the upright side walls and the top wall of which are substantially identical in shape to those of the steel container. 
     DESCRIPTION OF THE RELATED ART 
     Such a container is disclosed in GB-A-1276795. 
     Transport of plastics particle material in steel ISO containers or steel high-cube containers produces problems if the plastics particles come into direct contact with the steel inner surfaces of the container walls. Steel particles which come loose as a result of corrosion of these walls are extremely damaging to the extruder in which the plastics particle material is processed, whilst, moreover, the product emerging from the extruder will be of relatively low quality. The customary solution to this problem is to hang up a large plastics sack (inner liner) in the container and to feed the plastics particles into this. This solution exhibits a number of drawbacks. The fitting of a sack in a container, the filling of the sack and the emptying thereof is time-consuming. Moreover the sacks are difficult to empty fully, so that material is left behind. In order to keep the sacks in place as the container is tipped, a frame (bulkhead) is erected, which can consist of wood and/or cardboard and/or steel tubular profiles. These materials have to be removed, which can cause a problem. Sometimes the sacks tear, so that steel particles emanating from the container manage, after all, to find their way into the plastics material. The sacks are used once and thrown away, including the plastics granules remaining therein, which is bad for the environment and entails costs. 
     The above-mentioned GB-A-1276795 deals with the difficulties encountered in forming the connection at the angular joint between two meeting walls especially at a corner where three walls meet. This problem is due to the fact that the walls seldom abut at exactly right angles. This document does not give a solution for the above-mentioned problems. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to avoid the abovementioned problems with the transport of plastics particle material or other bulk material in containers, without experiencing the abovementioned drawbacks. 
     According to the invention, the steel container specified in the introduction is, to this end, characterized in that one or more fill openings are make either in a bulk head of the closed box or in the upper wall of the closed box, which fill openings may be closed off by a lid and can be brought in communication with the space outside the steel container via an open door or via an opening in the upper wall of the container, that one or more discharge openings are made either in a bulkhead of the closed box or in the lower wall of the closed box, which discharge openings can be closed off by a lid, and that the discharge openings are flanged by funnel-shaped bottom walls extending towards the discharge openings. 
     As the corrosion-resistant material, stainless steel and hard plastic (including composite) enter into consideration, though an aluminium alloy, for example an aluminium magnesium alloy, is preferable owing to the low price and low weight and the excellent anti-corrosive properties. 
     The transportation of solid plastics in the containers according to the invention, for example from the plastic producer to the processing plant, yields a positive environmental effect. The plastic remains pure. There is no loss of plastic. Both the steel walls of the container and the corrosion-resistant bin inside the container are recyclable. 
     In order to connect together the steel container walls and the walls of corrosion-resistant material, the fastening between the steel container walls and the walls of corrosion-resistant material can be formed by a bushing inserted through a mutually aligned opening in both walls and in which the screw bolt is turned, which bushing is deformed into an annular thickening lying against the outer side of the steel wall. Such a connection is denoted by the term blind rivet nut. At least the transitions from the long side walls into the top wall and from a short side wall into the top wall and the long side walls preferably comprise angled or rounded parts, which are welded at their bent-over flat ends to the vertical and horizontal walls of closed box 
     The internal bin of corrosion-resistant material must regularly be cleaned. This can easily be realized if a water pipe having spray openings emerging in the closed box of corrosion-resistant material is moulded onto those angled or rounded corner pieces of the box of corrosion-resistant material which run in the longitudinal direction of the container. 
     The invention further relates to a method for storing and transporting bulk material, especially plastics particle material, in containers, in which the bulk material is situated unpacked in the internal bin of a container according to one of the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be now explained in greater detail with reference to the figures, in which: 
     FIG. 1 shows a perspective view of a portion of an ISO container constructed according to the invention, 
     FIG. 2 shows a cross section through a corner of the container according to FIG. 1, 
     FIG. 3 shows a cross section through a wall of the container, 
     FIG. 4 shows a longitudinal section of the container according to FIGS. 1-3, 
     FIG. 5 shows a front view of the internal bin of the container according to FIGS. 1-4, 
     FIG. 6 shows a longitudinal section of a high-cube container according to the invention having a floor consisting of funnel-shaped discharge elements, 
     FIG. 7 shows a front view of the internal bin of the high-cube container according to FIG.  6 . 
     FIG. 8 shows a longitudinal section of an alternative embodiment of a high-cube container according to the invention which differs from that according to FIGS. 6 and 7 by the placement of fill openings in the top wall, 
     FIG. 9 shows a front view of the internal bin of the container according to FIG.  8 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In FIG. 1, a part of a steel ISO container  1  can be seen. Such containers are used in large numbers in the 20′, 40′, 30′ and 45′ sizes and possess at the comers usual facilities  2  to enable them to be locked to a hoisting trestle or to one another with the aid of twist locks. Inside the ISO container  1 , a bin  3  of corrosion-resistant material is fastened, the shape of which substantially conforms to the parallelepipedal shape of the ISO container. Unlike the ISO container, the bin  3  has angled or rounded transition parts  4  at the transitions from an upright long side into the floor and into the top wall; as well as at the transitions from the bin wall, situated close to the thick short side of the container, into the floor and top wall of the bin. These transition parts  4 —as shown by FIG.  2 —are fastened at bent-over end edges to the walls of the bin  3  by means of a weld joint  5  extending over the length of the wall concerned. 
     The flat walls of the bin  3  of corrosion-resistant material are fastened to the steel ISO container walls by means of connections, one of which is shown in cross section in FIG. 3. A bushing  6  made from deformable material is inserted through aligned openings in the steel wall of the container and the wall of the corrosion-resistant bin  3  and a screw bolt  7  is screwed through this bushing  6 . This bolt  7  presses with its head, via a sealing ring  8 , onto the corrosion-resistant material. On the opposite side, the screwed-in bolt has deformed the bushing material in such a way that the thickening  9 , which engages the steel wall of the container  1 , has been formed. Such a connection is referred to as a blind rivet nut. 
     The narrow upright wall of the bin  3 —the bulkhead, as it is known—which is situated close to the doors of the steel ISO container, is provided with a discharge opening  11  close to the floor of the bin  3 , which discharge opening can be closed off by a butterfly valve  10 , a manhole  13  close to the top wall of the bin  3 , which manhole can be closed off by a hinged door  12 , and two inspection holes  14 ,  15  somewhat below the manhole  13 . The bin is filled via the manhole  13 , a conveyor belt being able to be introduced temporarily through that manhole in order to bring bulk material, especially plastics particles, into the bin in well-distributed arrangement. The discharging of the bin is realized by tilting the container  1  with bin  3  and opening the butterfly valve  10 . At the sites of the opening  11 , angled partitions  16  are fitted, which prevent the material to be discharged from being left in the corners of the bin  3 . 
     The bin  3  preferably consists of an aluminium alloy, such as an aluminium magnesium alloy. This material is lightweight, is corrosion-resistant by virtue of the presence of an oxide film on the surfaces and is not unduly expensive. Stainless steel and a hard plastic, including a composite material, are not, however, precluded. 
     The embodiment according to FIGS. 6 and 7 does not relate to an ISO container, but to a high-cube container  17 , in which an internal bin  3  is fitted. This high-cube container with internal bin has a number of discharge openings  21 , which can be closed off by a valve  20  and which are situated at the bottom end of funnel-shaped floor parts  22 . The internal bin  3  is filled in the same way as the internal bin of the ISO container discussed above, that is to say via a manhole  13 , which can be closed off by a door  12 , and a conveyor belt, which can be introduced via that manhole. There are also inspection holes  14 ,  15 , which are closed off by glass. 
     It will be clear that this container does not need to be tilted during discharging, since the material leaves the container via the discharge openings  21 . The discharge openings  21  above the floor of the carbon steel container  17  are not precluded from emerging in a horizontal pipe, which is connected to a vacuum appliance for discharging of the bulk material. 
     The embodiment according to FIGS. 8 and 9 likewise relates to a high-cube container  17 , in which an internal bin  3  made of corrosion-resistant material is fitted. This container has on the top side a number of fill openings  19 , which can be closed off by a lid  18  and into which plastics material can be fed. As in the container according to FIGS. 6 and 7, discharge openings  21 , which can be closed off by a valve  20 , are made. These are situated at the bottom end of funnel-shaped floor parts  22 . 
     It is important that the inside of the bin  3  of corrosion-resistant material of the abovementioned containers can easily be cleaned on the inside. To this end, water pipes  24  are moulded onto the angled corner parts  4  of the internal bin  3  of the containers  1 ,  17  and  23 , which water pipes are provided at irregular intervals with spray openings  25 , which emerge in the inside of the bin  3 . The water pipes  24  are connected by snap couplings  26  (FIG. 4) to a water feed hose (not represented). Various modifications and additions are possible within the scope of the claims.