GB2250219A

GB2250219A - Separating solids

Info

Publication number: GB2250219A
Application number: GB9123786A
Authority: GB
Inventors: Eberhard Stodt; Erwin Kaldenbach
Original assignee: Lindemann Maschinenfabrik GmbH
Current assignee: Lyndex Recycling Systems Ltd
Priority date: 1990-11-12
Filing date: 1991-11-08
Publication date: 1992-06-03
Also published as: GB9123786D0; FR2668961A1; DE4035960A1

Abstract

An improved, reciprocating internal combustion engine is disclosed herein. This engine consists of multiple cylinders (1), each closed by a cylinder head (2) and containing a piston (3) which is connected to a power output shaft. Each cylinder (1) has means (6, 7) for the intake and exhaust of working fluid. It also contains a movable, thermal regenerator (8), an alternating flow heat exchanger, and means (10) to move this regenerator. Finally, means are provided for the introduction of fuel into the cylinder. Improvements include improved heating strokes, the use of unequal effective compression and expansion ratios, and non-direct fuel injection.

Description

) 2) 321 1 Method and apparatus for separatinq different sized components

of a solid mixture.

The invention relates to a method and an apparatus f or separating different sized components of a solid mixture, in particular from mixtures containing non-ferrous metals.

In order to recover valuable non-ferrous metals it is known to generate an alternating magnetic field, for example by means of an inductor or by means of a magnetic rotor, and to perf orm the so-called eddy current separation of non-magnetisable metals of good electrical conductivity. In this the material charged may be passed, for example on a conveyor or in free fall, over the poles of an alternating magnetic f ield generator. Eddy currents are induced in the electrically conductive components of the mixture to be separated, which build up their own magnetic field opposed to the generating field and thereby accelerate these components relative to the other components of the mixture by electromagnetic forces. Eddy current separation enables non-ferromagnetic materials of good electrical conductivity, such as aluminium. and copper, to be separated from nonferrous solid mixtures and nonferrous metal/non-metal solid mixtures, such as car shredder scrap, electronic scrap or the like. Should there be ferromagnetic fractions in these mixtures a magnetic separator can be arranged before the eddy current separator to first remove ferromagnetic fractions. In addition other sorting and classifying stages are advantageously arranged before the eddy current separation, since preenriching and fractionating the solid mixture charged as thoroughly as possible improves the separation and the throughput capacity of the eddy current separator.

In the preparatory sieving classification of a precomminuted solid mixture, in particular in sieving off a fraction that is smaller than 20 mm, numerous 30 to 70 mm 2 long pieces of thin wire from cables or the like also fall through the 20 mm or smaller sieve openings. These pieces of wire also consist of valuable, non-ferrous metals, generally copper, that it is desired to recycle, and in the case of the eddy current separator disclosed in DE-OS 39 09 499, which has a parting plate that projects into the turbulent zone of the magnetic field generator, they are carried over into the non- ferrous metal fraction. However, the pieces of wire interfere with the subsequent sorting of the non-ferrous metal mixture in a flotation plant. These pieces of wire, about 20 to 70 mm in length, are undesirable because they block up the sieves and material outlets in the flotation plant.

In practice where wires are undesired in the further processing of the non-ferrous metal fraction, e.g. in order to avoid breakdowns due to blockage in subsequent processing plants and in particular in said flotation plants, compromises in separation are made, namely part of the recyclable non-ferrous metals, in particular wire, is discarded so that there is an acceptable proportion of wire in the non-ferrous metal fraction. In the case of an eddy current separator this can be controlled through the speed of the conveyor supplying the mixture of material, the position of the separating saddle or both. However, this compromise leads to the following substantial disadvantages: loss of non-ferrous metals on the one hand and a corresponding non-ferrous-metal-containing waste fraction on the other hand. Recovery of the wire and non- ferrous metals contained in the waste fraction requires a separation in an expensive flotation plant to separate the valuable components from the relatively much larger proportion of waste. Separation by repeated sieving is out of the question, e.g. because experience shows that 30 to 70 mm long thin wires contained in a 0 to 20 mm fraction of a mixture would for the most part again fall through the small sieve openings.

3 It is an object of the invention to provide a method and an apparatus for separating such pieces of wire from a sieved-of f mixture of solid components having a particle size of less than 20 mm or from a mixture of non-ferrous metals of this fraction that has already been separated from the non- metallic components.

To this end, according to the invention in order to separate pieces of wire, nails or the like (hereinafter referred to as wire-like components) from a solid mixture with granular material that has been passed through a sieve with openings smaller than 20 mm, the solid mixture is conveyed on an endless conveyor with the wire- like components aligned in the direction of transport to a gap located in the conveying path immediately after the endless conveyor through which granular pieces of material can pass, the width of said gap being smaller than the shortest length of wire-like component to be separated out. In particular when a pre7sorted mixture of material, either as a preliminary treatment step or as a post-treatment step to an eddy current separation (a preliminary treatment step being understood as one in which the wires are first separated from a sieved mixture of non- ferrous metal, wire and waste and thereafter the remaining mixture of non- ferrous metal and waste passes through the eddy current separation) reaches the region of the gap in the conveying path in this way the granular components (either nonferrous metals or non-ferrous metals and waste components) of smaller dimensions fall downwards through the gap, while the wires pass over the gap and can thus be collected separately from the other components of the mixture.

The invention also includes an apparatus for carrying out the abovementioned method which comprises an endless conveyor, means for feeding a mixture of granular and wirelike components on to the conveyor, means for aligning the wire-like components on the conveyor substantially in the 4 direction of transport, and a transfer plate at the discharge end of the conveyor having its upper edge spaced from the conveyor to define a gap permitting the passage of granular components of the mixture but arranged to be bridged by wire-like components of greater than a preselected length. The width of the mouth of the gap is measured in the radial direction - referring to the head end of the endless conveyor, which as a rule is curved - at the throw-off zone. It need only be slightly larger than the largest particle, within the dimensional limits, obtained by sieving. To align the wires a vibrating chute (vibrating conveyor) having longitudinal grooves in which the wires being aligned in the longitudinal direction by the vibrations lie, can be provided before the endless conveyor. Alignment of the wires also occurs in the transfer of the solid mixture from the preceding feed conveyor, such as a vibrating chute, to the endless conveyor because, as a rule, the two ends of the wires do not meet the endless conveyor simultaneously. The end of the wire that reaches the endless conveyor first is thus already being transported in the conveying direction before the other end of the wire reaches the endless conveyor. This means that the wires are aligned on the endless conveyor. This effect is further magnified by reason of the greater speed of the endless conveyor, since the ends of the wires lying on the endless conveyor are accelerated first. Finally sharply pointed aligning stops could also project into the stream of material and align the wires without causing a jam.

In an apparatus for separating said sieved solid mixture the gap is located between an endless conveyor and a transfer plate that is preferably arranged so that the largest granular components of the sieved fraction only 35 just pass through between the endless conveyor and the transf er plate. This improves the separation as wires thrown off at the end of the endless conveyor will then not 1 1 fall down in front of the transfer plate (in the direction of movement of the material) but will bridge the gap in front of the transfer plate and be guided to the wire collecting zone located further on.

It is advantageous to arrange the transfer plate with its end close to the material throw-of f line. However, the width of the mouth, i.e. the gap distance measured in the radial direction f rom the curve of the head end of the endless conveyor to the upper edge of the transfer plate, depends on the particle size range and is only slightly larger than the size of the largest particle present. The material throw-of f line is reached when the mixture of granular material charged just begins to slide or f all under gravity on a curved line formed at the throw-off end of the endless conveyor, i.e. in its deflecting zone, and separates f rom the conveyor. Consequently the transfer plate projects a long way upwards and prevents the nonferrous metals, or non-ferrous metals and waste material, f rom entering the path into which the wires are diverted and f rom mixing with them. Depending on the conveying speed the granular material components fall substantially vertically downwards bef ore having had any real opportunity to enter a trajectory parabola, or else they strike the side of the transfer plate facing them and bounce off it. The wires to be separated. on the other hand, cannot fall because, owing to their length, they only tip downward later, and cannot fall downwards through the mouth of the gap, which is very much narrower than their length.

Instead they bridge the width of the mouth of the gap between the throwoff end of the endless conveyor and the upper edge of the transfer plate and are intentionally guided via the transfer plate, as a kind of slide, to the wire collecting zone.

When, as is preferred, a variable speed endless conveyor is used, the conveying speed, which is one of the 6 factors determining the trajectory parabolas, can be adapted to the particular composition of the mixture.

It is advantageous if the endless conveyor has a driven conveyor belt that is guided over tail pulleys at least at the feed and throw-off ends. If the tail pulley at the throw-of f end of the endless conveyor is used as the reference point for the position of the upper edge of the transfer plate, the upper edge can lie clearly above the horizontal axis of the tail pulley. Thus in the case of known eddy current separators, which have a conveyor belt running over pulleys, an alternating magnetic field generator arranged in the f ront pulley and a separating saddle arranged high up in front of the front pulley, it is possible, using the idea on which the invention is based, to provide an apparatus for separating wires according to the invention by passing a previously magnetically separated mixture of material or a sieved mixture of material still containing non-ferrous metals and pieces of wire and waste material over the separator in a separate operation providing it is switched off, i.e. is not generating eddy currents, and can thus be used as a wire separator. It is also necessary, in complete contrast to the known eddy current separators with a raised parting plate, where pieces of wire and non-ferrous metals end up in the same mixed fraction (which is exactly what the invention avoids), to make the width of the mouth between the endless conveyor and the transfer plate so small that it is only slightly (about 2 mm) larger than the known 30 largest particle (20 mm) in the sieved mixture of material.

For continuous operation it is however advantageous to arrange a separating device according to the invention either after or before a known eddy current separator.

If the - advantageously multi-part - transfer plate is adjustable, e.g. has adjustable angle of inclination or height and can also be moved horizontally, it is simple to 7 obtain suitable settings for any given operating conditions.

is Further features and advantages of the invention are set forth in the claims and in the following description, in which an embodiment of the subject matter of the invention is described in more detail by way of example.

Fig. 1 Fig. 2 shows, in a diagrammatic side view, an apparatus according to the invention f or separating wires from a mixture of material, and shows a detail of the throw-off end of the separating apparatus according to Fig. 1 on a larger scale.

In a preferred apparatus within the scope of the invention an endless conveyor 1 comprises an endless circulating conveyor belt 2 that is guided over tail pulleys 5, 6 at the feed and throw-off ends 3, 4. The rear tail pulley 5, at the feed end 3, is provided with a drive (axial cylinder engine) by means of which the speed of the conveyor belt 2 can be continuously adjusted.

Adjacent to the endless conveyor 1 at the throw-off end 4 is a transfer plate 7 made up of several parts and comprising a supporting frame 8 and a plate 11 that can be tilted therewith in the direction of the double arrow 9. The upper edge 12 of the transfer plate 7 or the plate 11 lies well above the horizontal middle axis 13 of the front tail pulley 6; the transfer plate 7 ends at the level of and close to the material throw- off line 14 - shown diagrammatically in Fig. 1 - on the front tail pulley 6. The material throw-off line 14 - whose position moves around the periphery of the pulley 6 depending on the composition of the material and the speed of the conveyor belt 2 - is located at about the point where a mixture of 8 material 15 transported by the conveyor belt 2 just begins to slide or f all under gravity in the region of the tail pulley 6 and separates from the conveyor belt 2. The upper edge 12 of the transfer plate 7 is spaced from the head or throw-off end 4 of the endless conveyor 1 so as to define a gap 16, with the distance, measured in the radial direction with reference to the curvature, from the front tail pulley 6 or the conveyor belt 2 to the upper edge 12 of the plate 11 of the transfer plate 7 corresponding to the width of the mouth of the gap 16. The width of the mouth of the gap 16 is smaller than the length of the wires 17 (cf. Fig. 2) in the mixture of material 15 and larger than the granular non-ferrous metals 18 also contained in the pre-sorted mixture of material 15. The transfer plate is 7, which is at least as wide as the conveyor belt 2, may besides the tilting adjustment according to arrow 9 - also be adjusted horizontally in the direction of the double arrow 19 and in height in the direction of the double arrow 21, so that variable- setting positions adapted to the respective operating conditions are possible.

To separate wires 17 from a pre-sorted mixture of material 15 that also contains non-ferrous metals 18 in addition to the wires, the mixture of material 15 is 25 charged on to a vibrating chute 22 formed as a feed conveyor. While being transported in the conveying direction 23 the mixture of material 15 is made uniform in height and width on the vibrating chute 22 and at the same time the wires 17 are aligned in the longitudinal 30 direction. So that the wires 17 retain their alignment the vibrating chute 22 may be provided with longitudinal grooves. The vibrating chute 22, which is inclined in the conveying direction 23, deposits the mixture of material 15 on to the conveyor belt 2 of the endless conveyor 1 from a 35 small height. If at this stage any wires 17 have not yet been aligned the following occurs: when the wires 17 fall from the vibrating chute 22 on to the conveyor belt 2 the 1 9 two ends of the wire 17 do not meet the conveyor belt 2 simultaneously. The end of the wire that reaches the conveyor belt 2 is thus already being transported in the conveying direction before the other end of the wire reaches the conveyor belt 2, so that alignment of the wires is also effected in this way. The speed of the conveyor belt 2 is greater than the conveying speed of the vibrating chute 22 so that the layer of mixed material 15 is further reduced in depth to a single layer by the transfer to the conveyor belt 2.

The mixture of material 15 is transported far beyond the crown (cf. the vertical 25) of the tail pulley 6 by means of the conveyor belt 2. On reaching the material throw-off line 14 the mixture of material 15 begins to fall or slide and separates from the conveyor belt 2. While the small pieces of non-ferrous metal 18 fall downwards through the gap 16 between the transfer plate 7 and the conveyor belt 2 in a substantially vertical trajectory parabola 26 (cf. Fig. 2), the wires 17 on the other hand pass unchecked over the gap 16 (cf. Fig. 2). Owing to their length the wires 17 bridge the gap 16 and are lifted over f rom the upper edge 12 of the plate 11 of the transfer plate 7 on to the f ar side - viewed in the transporting direction - of the transfer plate 7 (or the plate 11) where they essentially slide downwards on the rear side 27 of the plate 11, as indicated by the arrow 28 in Fig. 2.

In any event the transfer plate 7 (or plate 11) which terminates with its upper edge 12 only a small distance from the outer surface of the conveyor belt 2 in about the region of the material throw- of f line 14 gives a clean separation of the wires 17 from the non- ferrous metals 18. This is because, while the wires 17 pass unchecked across the narrow gap 16 between the conveyor belt 2 and the upper edge 12 of the transfer plate 7 and thus arrive in a wire collecting container 29 arranged behind the transfer plate 7 (viewed in the direction of transport 23), the nonferrous metals 18 fall downwards through the gap 16 substantially vertically (cf. the trajectory parabola in Fig. 2) and end up before (viewed in the conveying direction 23) the transfer plate 7 in a non-ferrous metal container 31 that is arranged there.

Claims

1. A method for separating wire-like components from different sized granular components of a solid mixture that has been passed through a sieve with openings smaller than 20 mm which comprises conveying the solid mixture on an endless conveyor with wire-like components aligned in the direction of transport to a gap located in the conveying path immediately after the endless conveyor through which granular components of the material can pass, the width of the mouth of the gap being smaller than the shortest length of wire-like component to be separated out.

2. A method according to claim 1 wherein the width of the mouth of the gap is such that the largest granular components of the sieved mixture can only just pass through it.

3. A method according to claim 1 or claim 2 wherein the wire-like components are of non-ferrous metal.

4. An apparatus for carrying out the method according to claim 1 which comprises an endless conveyor, means for feeding a mixture of granular and wire-like components on to the conveyor, means for aligning the wirelike components on the conveyor substantially in the direction of transport. and a transfer plate at the discharge end of the conveyor having its upper edge spaced from the conveyor to define a gap permitting the passage of granular components of the mixture but arranged to be bridged by wirelike components of greater than a preselected length.

5. An apparatus according to claim 4, wherein the width of the mouth of the gap is such that the largest granular components of the sieved mixture can only just pass through it.

1 12

6. An apparatus according to claim 4 or claim 5, wherein the transfer plate ends close to the material throw-off line of the endless conveyor.

7. An apparatus according to any one or more of claims 4 to 6, wherein the transfer plate is adjustable.

8. An apparatus according to any one or more of claims 4 to 7, wherein the transfer plate comprises several 10 parts.

is

9. An apparatus according to any one or more of claims 4 to 8, wherein the endless conveyor is a variable speed conveyor.

10. An apparatus according to any one or more of claims 4 to 9, wherein the endless conveyor has a driven conveyor belt that is guided over tail pulleys at least atthe feed and throw-off ends.

11. An apparatus according to any one or more of claims 4 to 10, wherein the means for feeding the mixture to the endless conveyor is a vibrating conveyor having longitudinal grooves in which the wire-like components can 25 lie.

12. A method according to claim 1 substantially as herein described by way of example with reference to the accompanying drawings.

13. An apparatus according to claim 4, substantially as herein described by way of example, with reference to the accompanying drawings.

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