Device for cooling and/or drying bulk goods

Abstract: The invention relates to a device for cooling and/or drying bulk goods, provided with a bunker (2) having a supply opening (12) for the material to be cooled, said supply opening being located near the upper side of the bunker, and with a single grate construction located near the bottom side of the bunker. The grate construction has been provided with a number of bar-shaped means (4) extending at least substantially parallel to each other. Further there are means for supplying cooling and/or drying air to the interior of the bunker through the grate construction at the bottom side of the device and for discharging said air near the upper side of the device after is has flowed through the material. The bar-shaped means can be pivoted forwards and backwards about a centre position during operation and are provided with plate-shaped parts (9-11) extending along both sides of the longitudinal axes, said plate-shaped parts being arranged such that they can overlap each other during normal operation. The centre position of the bar-shaped means is adjustable and the bar-shaped means (4) with the plate-­ shaped means (9-11) fixed thereto can be pivoted forwards and backwards in any set centre position. Preferably the plate-shaped parts (9-11) are perforated.

Description: The invention relates to a device for cooling and/or drying bulk goods, provided with a bunker having a supply opening for the material to be treated, said supply opening being located near the upper side of the bunker, and with a grate construction located near the bottom side of the bunker, said grate construction being provided with a number of bar-shaped means extending at least substantially parallel to each other being pivotable about axes of rotation extending in the longitudinal direction of the bar-shaped means and being provided with plate-shaped parts which by pivoting of the bar-shaped means can be arranged such that the plate-shaped parts of adjacent bars overlap each other, as well as with means for supplying cooling and/or drying air to the interior of the bunker through the grate construction at the bottom side of the device and for discharging said air near the upper side of the device after it has flowed through the material. From DE-C-406 there is known a device having various grate constructions, one arraged above the other and each having upper plate-shaped members, which can be moved up and down and rotated and lower plate-shaped members, which can be rotated. Contrary thereto the invention aims at a device having a simple structure with only a single grate structure. However the dimensions of the products which are processed in such a device, such as mealy products, granular products, flaky products, cylindrical products etc., can vary within ample margins. Usually the varying dimensions of the products also require varying dimensions of the passages present between the parts of the grate construction for passing the material. With the known grate constructions the dimension of said passages can usually be used for a certain material only and when another and/or finer and/or coarser material is to be processed it is necessary to use another decive or to build in another grate in a particular device. The purpose of the invention is to obtain a device of the above kind which is suitable for processing a large number of different bulk goods. According to the invention this can be achieved in that the pivot axes of the bar-shaped means forming the single grate construction of the device have a fixed position with respect to each other and are lying at least substantially in a single plane whereby each bar-shaped means comprises two plate-shaped parts extending essentially parallel to and spaced from each other and a third plate-shaped part extending transverse to said two essentially parallal plate-shaped parts, whilst the device comprises a drive mechanism for rotating the bar-shaped means about said pivot axes for adjusting the bar-shaped means between various starting positions and for pivoting the bar-shaped means to and fro over the same angle about the axes of rotation in any said starting position whilst means has been provided for adjusting said angle. The passages for passing the material bounded by the overlapping plate-shaped parts can be adjusted in a simple manner by changing the starting position of the bar-shaped means, whilst in every starting position an even discharge of the products to be processed can be ensured because of the possibility to pivot the bar-shaped means with the plate-shaped parts fixed thereto forwards and backwards from said starting position. It is noted that from the British patent specification 9801/1912 there is known a drying device provided with a large number of floors arranged at relatively short distances above one another, said floors being built up of partly overlapping tiltable plates. Drying air is supplied between said floors and can flow out via passages provided between the plates. At set intervals the plates forming a floor will be tilted in order to deposit the material present thereon onto a floor located thereunder. Thus the material will be moved in steps from the one floor to the next floor. From said publication there is not known, however, a device provided with a bunker for taking up the bulk goods and with a single grate construction located near the bottom side of the bunker, built up of bar-shaped means, which bar-shaped means can be pivoted forwards and backwards during operation in order to be able to ensure a regular outflow of the material from the bunker. Nor can an indication be found in said publication with regard to a possible adjustment of the device for processing various kinds of materials. From the German patent specification 318,693 there is known a similar drying device, provided with a number of floors located at short distances above one another, said floors being built up of a large number of plate-shaped parts which may overlap one another. The plates are jointly pivotable thereby from the position in which they form a floor into a position in which the material lying on a floor falls in one movement onto a floor located thereunder. Neither is any indication provided in this publication, therefore, with regard to the construction of a drying device provided with a bunker containing the material to be processed and a single grate construction located at the bottom side thereof, as constructed in accordance with the proposal according to the present invention. In some cases problems may arise when fine products, such as mealy products, are processed when non-perforated plate-shaped parts are used because, also when the plate-shaped parts are set such that only narrow gaps are present between adjacent plate-shaped parts, so much air is still sucked in through the gaps that local passages are formed in the layer of meal or the like material supported by the plate-shaped parts. As a result there may be a very irregular distribution of the air speed and an irregular degree of flow of air through the meal or the like material on the surface of the grate construction in such a case. According to a further aspect of the invention such a disadvantage can be met in that the plate-shaped parts are perforated. When using such perforated plate-shaped parts it will be possible, when meal or the like fine material is processed, to put the plate-shaped parts into such a position that the edges of the plate-shaped parts are at least substantially in contact with one another, and it is practically only possible for the air to flow through the perforation openings during operation, as a result of which an even passage of air through the material to be processed can be ensured. The invention will be further explained hereinafter with reference to an embodiment of the construction according to the invention diagrammatically illustrated in the accompanying figures. Fig 1 is a diagrammatic view of a device according to the invention. Fig 2 illustrates a few bar-shaped means according to a first embodiment of the invention in three different positions. Figs 3 - 5 illustrate a few further embodiments of the bar-shaped means, each illustrated in three different positions. Fig 6 diagrammatically illustrates a part of a mechanism for regulating the pivoting of the bar-shaped means about their longitudinal axes. The device illustrated in fig 1 comprises a frame 1 on which there is placed a bunker 2. Under the bunker there is located a chute 3 supported by the frame. Between the bunker 2 and the chute 3 there is arranged a grate construction, which is built up of a number of bars 4 extending parallel to each other, which bars are rotatably journalled near their ends in bearings, not shown, fixed to the frame, such that the bars 4 are pivotable about their longitudinal axes. To the ends of the bars 4 there are furthermore fitted arms 5 which are mutually coupled by a coupling rod 6 only diagrammatically indicated by means of a chain-dotted line. One of the arms 5' is longer than the other arms 5 and is coupled, with its end remote from the relevant bar-shaped means 4, to the piston rod of a setting cylinder 7, which setting cylinder is coupled to the frame with its other end. During operation the bar-shaped means 4 can be pivoted forwards and backwards about their longitudinal axes by means of the setting cylinder 7. As is also further illustrated in fig 2 three plate-shaped parts 9 - 11, extending along the entire length of the bar-shaped means, are fixed to each bar-shaped means 4. As appears from the figures thereby the two plate-shaped parts 9 and 10 extend parallel to and spaced from each other because they are located on both sides of the bar-shaped means 4 in question and extend in opposite directions from said bar-shaped means 4 thereby. The third plate-shaped means 11 may be perpendicular to the two plate-shaped parts 9 and 10 and extends downwards in the position of the plate-shaped parts illustrated in fig 1. At its upper side the bunker 2 is provided with a cellular valve 12, via which bulk goods to be processed can be supplied to the interior of the bunker. Cold or hot air for cooling and/or drying can be supplied to the interior of the bunker 2 via the grate formed by the bar-shaped means 4 with the plates 9 - 11 fixed thereto, as indicated by means of the arrows A and, after having flowed through the material present in the bunker 2, be discharged via a pipe 13 connected to the upper side of the bunker 2. Material flowed from the bunker 2 into the chute 3 through the grate-shaped means can be discharged via a spout 14 provided at the bottom side of the chute 3. As is illustrated in fig 2a the bar-shaped means 4 forming a grate can be pivoted such that the free ends of the overlapping parts 9 and 10 of adjacent bar-shaped means substantially touch each other or are located at short distances from each other, such that the gaps still present between the plate-shaped parts 9 and 10 of the grate-shaped construction are too small to pass the material, so that no flow of the material from the bunkers is possible. From the position of the bar-shaped means illustrated in fig 2a, in which the outlet from the bunker will be at least substantially closed, the bar-shaped means can be pivoted to an intermediate position illustrated in fig 2b, in which the distance between the overlapping plate-shaped means is such that material present in the bunker 2 can flow out via the gap present between the plate-shaped means. In order to start and stop said outflow the bar-shaped means 4 can thereby be pivoted at an angle about the set intermediate position or centre position by means of the setting cylinder 7, as a result of which the material lying on the plate-shaped means 9 will be put into a slight upward and downward movement. In particular when products which tend to stick are processed such a displacement of the material in order to loosen the material is important. The bunker above the grate construction may be slightly conical towards the top, which will prevent bridge formation in the material in the bunker. Because in the centre position illustrated in fig 2b the free end of the plate-shaped part 10 across which the material flows out of the bunker is located at a short distance from the plate-shaped part 11 extending perpendicularly to said plate-shaped part 10, which plate-shaped part 11 extends some distance under the edge of the plate-shaped part 10, it is prevented that the material flows out of the bunker too quickly, because the material is braked, as it were, by the plate-shaped part 11. At the same time the plate-shaped part 11 contributes to the rigidity of the bar-shaped means 4 in order to prevent bending of said bar-shaped means 4 under the influence of the weight of the material present in the bunker. When it is desired to empty the bunker quickly the bar-shaped means can be pivoted from the position of the grate illustrated in fig 2a or b at an angle of about 90°, so that the plate-shaped parts 9 and 10 extend at least substantially vertically thereby, whilst there is a relatively large gap present between the free boundary edge of a plate-shaped part 11 located substantially horizontally in that case and an adjacent bar-shaped means 4. Thus large passages are formed between the adjacent bar-shaped means 4, through which the material can flow out freely and without impediment. A little material at the very most will remain behind on the plate-shaped parts 11 located substantially horizontally in that case, but this material will also be discharged when the bar-shaped means are pivoted back towards the closed position of fig 2a. As is illustrated in more detail in figs 3 - 5 the shape of the plate-shaped means may possibly be adapted to the nature of the products which will mainly be processed in the device. Thus, in the embodiment according to fig 3, the ends 15 of the plate-shaped parts 10 are bent upwards a little in the direction of the plate-shaped parts 9 located thereabove. As a result of this the gap between the overlapping plate-shaped parts can be reduced in a simple manner in the closed position of the grate. In the embodiment according to fig 4 not only the edges 15 of the plate-shaped parts 10, but also the edges 16 of the plate-shaped parts 9 are bent upwards. The upwardly bent edges of the plate-shaped parts 9 will thereby have an extra scraping effect on the material in the bunker 2 when the bar-shaped means are pivoted forwards and backwards during operation. In the embodiment according to fig 5, on the contrary, the edges 17 of the plate-shaped parts 9 are bent downwards, in order to prevent that e.g. small spherical products flow through the grate in the so-called closed position of the grate. There should always remain an opening between plate parts 9 and 10 for the passage of the air. Fig 6 illustrates a part of a mechanism for regulating the stroke of the setting cylinder 7 or the angle at which the bar-shaped means are pivoted during operation. For that purpose an arm 18 is fixed to one of the bar-shaped means 4, which arm co-operates with a pair of switches 19 and 20 arranged on both sides of the arm. The switch 19 is thereby movable in horizontal direction and adjustable between the position 19 and the position 19' illustrated by dotted lines. In a similar manner the switch 20 is adjustable in horizontal direction between the position 20 and the position 20' illustrated by dotted lines. When the arm 18 touches one of the switches the direction of rotation of the bar-shaped means will be reversed via a mechanism (not shown). It will be apparent that the angle at which the bar-shaped means are pivoted and the place of said angle can be influenced by adjusting the switches 19 and 20. A further switch 21, having a fixed arrangement and co-operating with the arm, is used for stopping the pivoting motion when the bar-shaped means 4 have been put in the completely open position, as is e.g. illustrated in fig 2c. For processing very fine products, e.g. meal, it is desirable to perforate at least those parts of the plate-shaped parts that project from the bar-shaped means. When the plate-shaped parts 9 and 10 are then pivoted into such a position that the free edges of adjacent plate-shaped parts at least substantially rest on each other, the air supplied will mainly be supplied to the layer of material lying above the plate-shaped means 9 and 10 exclusively via the perforations, so that a very even distribution of air over the grate surface is obtained. For the discharge of material the plate-shaped parts can be pivoted at desired moments to a position in which the material can flow out through the gaps formed between the plate-shaped parts. The bars 4 may be hollow and perforated, so that a supply of air over practically the entire grate surface can be created.

Claims: Device for cooling and/or drying bulk goods provided with a bunker (2) having a supply opening (12) for the material to be treated, said supply opening (12) being located near the upper side of the bunker (2) and with a grate construction located near the bottom side of the bunker, said grate construction being provided with a number of bar-shaped means (4) extending at least substantially parallel to each other, being pivotable about axes of rotation extending in the longitudinal direction of the bar-shaped means and being provided with plate-shaped parts (9, 10), which by pivoting of the bar-shaped means can be arranged such that the plate-shaped parts of adjacent bar-shaped means overlap each other, as well as with means for supplying cooling and/or drying air to the interior of the bunker through the grate construction at the bottom side of the device and for discharging said air near the upper side of the device after it has flowed through the material, characterised in that the pivot axes of the bar-shaped means (4) forming the single grate construction of the device have a fixed position with respect to each other and are lying at least substantially in a single plane, whereby each bar-shaped means (4) comprises two plate-shaped parts (9, 10) extending essentially parallel to and spaced from each other and a third plate-shaped part (11) extending transverse to said two essential parallel plate-shaped parts (9, 10), whilst the device comprises a drive mechanism (7, 18-20) for rotating the bar-shaped means (4) about said pivot axes for adjusting the bar-shaped means between various starting positions and for pivoting the bar-shaped means to and fro over the same angle about the axes of rotation in any said starting position whilst means (18-20) has been provided for adjusting said angle. Device according to claim 1, characterised in that the plate-shaped parts (9-11) are perforated. Device according any one of the preceding claims, characterised in that the third plate-shaped part (11) of a bar-shaped means (4) extends downwards during normal operation at some distance from a boundary edge of one of the other plate-shaped parts (10) of said bar-shaped means (4). Device according to any one of the preceding claims, characterised in that the free edge of a plate-shaped part (9, 10) is bent upwardly. Device according to any one of the preceding claims, characterised in that the plate-shaped parts (9-11) are fixed to a hollow bar (4) provided with perforations.

Inventors: GEELEN PIERRE MARIE LAMBERT, GEELEN, PIERRE MARIE LAMBERT
Applicants: GEELEN TECHNIEK, GEELEN TECHNIEK B.V.
Application year: 1988
Main classification: F26B17
IPC codes: F26B17, F25D1, F26B25, F26B3