Device for transporting bulk materials

Abstract

Device for transporting bulk materials, comprising a conveying trough (1) having at least one tubular conveying trough section (2), in which fluidizing gas can be introduced into the lower region of the pipe cross-section via at least one main channel (3) or main channel section (11) extending longitudinally in the conveying trough (1) and gas outlet channels (4) branching off from it at intervals, wherein the at least one main channel (3) or main channel section (11) extends outside the conveying trough (1) or the respective conveying trough section (2), wherein the gas outlet channels (4) are designed at least at their gas outlet ends as nozzle pipes (6) branching off from the main channel (3) or the respective main channel section (11), characterized in that the nozzle pipes (6) extend obliquely from the side through the pipe wall (5) into the lower region of the conveying trough (1) or the respective main channel section (2) at their gas outlet end.of the respective conveying channel section (2) are directed downwards.

Description

The invention relates to an apparatus for transporting bulk materials, having a conveying chute which has at least one tubular conveying-chute section, in which fluidizing gas can be introduced into the lower region of the tube cross section via at least one main duct or main-duct section running in the longitudinal direction of the conveying chute or of the conveying-chute section and gas outlet ducts branching off from the latter at intervals.Such devices serve, for example, for the pneumatic transport of pulverulent bulk materials, such as dry aluminum hydrate, from an electrostatic filter to an airlift within a calcination plant or for transporting aluminum oxide to a silo. Such devices can also be used for transporting any other desired bulk material.Classic fluidizing conveyor channels are distinguished, for example, by an inclined rectangular housing channel which is provided with a fluidizing base in its lower region. When the bulk material is fluidized via the fluidization tray, it behaves as a liquid and flows in the direction of the gradient. The fluidizing base is usually made of a porous material in the form of a fine cloth or a more stable sintered metal membrane through which the fluidizing gas can flow but through which the solid cannot fall. However, the cloth may easily tear, wear and clog over time. In sintered metal membranes, blockages often occur over time as a result of very fine particles which become fixed in the pores of the sintered metal. Both lead to the fluidization base having to be exchanged regularly. When the bulk material is moist, it can even block immediately by "cementing", which requires replacement of the fluidization base. Also when sharp-edged objects are introduced into the stream of bulk material, for example during maintenance work, the fluidization base can be damaged. At the bulk material inlet of conventional fluidization feed troughs, a grid is therefore required. When objects are accumulated on the grid, it must be cleaned from time to time. A further disadvantage of conventional fluidising conveyor channels with a rectangular housing channel is the risk of leaks in the flange connections running in the longitudinal direction of the channel.DE 197 09 425 C1 discloses a device for fluidizing and transporting fine-grained, pulverulent or short-fiber materials within a hose, tube or container, to which fluidizing gas is fed via a main channel running in the longitudinal direction of the hose, tube or container and a plurality of throttle connection channels arranged one behind the other. The main channel and the throttle channels are arranged within a gas distribution profile element provided on the inner side of the hose, pipe or container wall and are connected via intermediate chambers to the interior of the hose, pipe or container via a plurality of gas outlet channels arranged next to one another in the longitudinal direction in the gas distribution profile element. As a result, only a part of the above-described disadvantages is eliminated. In addition, there is the problem that the main channel, throttle connecting channels, intermediate chambers and gas outlet channels arranged within the hose, pipe or container are difficult to access in the event of maintenance and, for example, also do not permit regulation of the fluidizing gas over the length of the conveying channels.Similar disadvantages exist in a device for pneumatic conveying of bulk materials in the dense phase process, which is known from EP 1 623 941 A1. This device for the pneumatic conveying of a pourable material in a dense phase process comprises a conveying line which is closed in cross-section and has a conveying channel, a compressed gas bypass line having a compressed gas channel and compressed gas passage means for feeding the conveying channel with a compressed gas from the compressed gas channel. The conveying channel is assigned a fluidization device which contains a fluidization channel with a fluidization channel and fluidization gas passage means for feeding a fluidization gas from the fluidization gas channel into the conveying channel. The fluidizing body and the tubular fluidizing gas channel are likewise accommodated within the conveying line which is closed in cross section, with the same problem of lack of accessibility for maintenance and / or repair work.From GB 1 035 584 A a pneumatic conveyor for loose material is known, with a conveying line and a parallel arranged gas supply line. Gas outlet channels run from the gas supply line from below into the conveying line, wherein the gas outlet channels end in a curved section in the conveying line or open obliquely from below into the conveying line.DE 202 11 376 U1 describes a device for pneumatic conveying of bulk material, having a conveying pipe and a nozzle designed as a pipe for introducing compressed air into the conveying pipe. The tube forming the nozzle passes perpendicularly from above through the lateral surface of the conveying tube as far as into the middle of the conveying tube and ends in a section which is curved in the conveying direction, so that the nozzle opening is aligned in the conveying direction, or has on its lateral surface an opening aligned in the conveying direction, through which compressed air is introduced into the conveying tubeDE 30 24 568 C2 describes a device for pneumatic conveying of conveyed material with a conveying line to which two high-pressure bypass accumulators run parallel and from which a plurality of individual gas lines emerge, which open into the conveying line at an acute angle. The gas lines end at an inlet in the wall of the conveying line.The conveying device described in FR 1 491 292 A comprises a pipeline to which a gas line running parallel below the line is connected, branches which open into a nozzle which opens obliquely from below into the line below a porous separating wall in the base region extending from the line.The object of the present invention is to provide an apparatus for transporting bulk materials, in which the disadvantages described above do not occur and in particular easy accessibility and controllability of the fluidization device is provided.To achieve this object, according to the invention, in a transport device having the features of claim 1, it is provided in particular that the at least one main channel or main channel section extends outside the conveying channel or the respective conveying channel section and the gas outlet channels are formed at least at their gas outlet ends as nozzle pipes branching off from the main channel or the respective main channel section and directed obliquely downward from the side through the pipe wall of the conveying channel or the respective conveying channel section.The conveying channel is thus composed, for example, of conventional round pipe sections which are to be connected to conventional flange connections on the end face. This eliminates leaks at flange connections running over the entire length of the conveying channel. For fluidization, tube nozzles can be used which are introduced obliquely from the side into the conveying channel, with their gas outlet ends directed obliquely downwards, so that penetrated solid can easily flow out of them again. The fluidizing nozzles are supplied with air via a main channel, preferably one on each side per conveyor channel section. In order to achieve an equal distribution of the air in the conveying channel, the fluidizing nozzles can be provided, for example, independently of one another with adjustable flow resistances. The quantity of fluidizing gas is smaller in the tubular conveying channel than in a rectangular conveying channel because of the round cross section. Due to the largely closed-off condition of the conveying channel, it is also suitable for the overpressure operation. Since no fluidization tray is required any longer, the transport device according to the invention is insensitive to mechanical influences, so that a grid at the bulk material inlet is unnecessary. There is also no sensitivity to moisture. A further important advantage is, in particular, that the entire fluidizing gas supply system is easily accessible, so that in the event of faults such as, for example, clogging of the nozzles, easy access is provided for maintenance and repair work. Cleaning by means of water is also readily possible.In the dependent claims, particular features of the novel transporting device are designated in more detail.In a special embodiment of the inventive idea, each conveying channel section is assigned at least one separate main channel section which can be supplied separately with fluidizing gas.If two main channels or main channel sections are located symmetrically to the vertical longitudinal central plane of the conveying channel or conveying channel section in the upper region of the latter, uniform supply of fluidizing gas can be achieved in a simple manner.With the aid of the flow resistances, undesired non-uniformities in the supply of fluidizing gas into the conveying channel can be compensated.For simplicity and for space saving reasons, the at least one main channel or the at least one main channel sections can be fastened on the outside to the tube wall of the conveying channel.In practical operation, the positioning of the nozzle tubes is provided, for example, at distances of about 100 to 400 mm, preferably about 150 to 250 mm.For the correct conveyance of the bulk material, an inclination of the conveying channel or of the conveying channel sections can be utilized. The inclination of the conveying channel is, for example, about 1 to 20°, preferably about 5 to 15°.In order that the conveying channel can also be used for use with bulk material having an elevated temperature of up to 1200° C., it is preferably supported by a steel framework and / or a lining.For assembly, adjoining conveyor channel sections are connected to one another in a sealing manner via end-face flanges.Due to the good accessibility of the gas fluidization system, the nozzle pipes can also be provided, for example, with cleaning and / or piercing openings accessible from outside the conveying channel.Further developments, advantages and possible applications will become apparent from the following description of an exemplary embodiment and the drawing. All features described and / or graphically depicted form the subject matter of the invention by themselves or in any combination, irrespective of their summary in individual claims or their reference back.The single FIGURE illustrates in oblique view a part of a transporting device having the invention.The device for transporting bulk materials, which is shown schematically in the drawing, has a conveying channel 1, which is formed from individual tubular conveying channel sections 2. Each conveying channel section 2 is assigned a main channel section 11 of a main channel 3 with fluidizing gas feed connection 10, and specifically preferably two such main channel sections 11 in the respective upper region of the respective conveying channel section 2 symmetrically with respect to the vertical longitudinal center plane of the conveying channel 1. Gas outlet channels 4 branch off from the main channel 3 or the respective main channel sections 11 at intervals, via which fluidizing gas can be introduced into the lower region of the tube cross section.The main channel 3 runs or the main channel sections 11 each run outside the conveying channel 1 or the respective conveying channel section 2, to which the respective main channel 3 or the respective main channel sections 11 can / can be attached. The gas outlet channels 4 are in any case formed at their gas inlet end in the lower region of the conveying channel 1 as nozzle pipes 6 directed obliquely downwards from the side through the pipe wall 5.The individual gas outlet channels 4 can be provided with preferably individually adjustable flow resistances 7.The positioning of the nozzle pipes 6 is provided, for example, at distances of approximately 100 to 400 mm, preferably approximately 150 to 250 mm.Cleaning and / or piercing openings on the nozzle pipes 6 are not shown in the drawing.List of reference numbers:1 Conveying channel 2 Conveying channel sections 3 Main channel 4 Gas outlet channels 5 Pipe wall 6 Nozzle pipes 7 Flow resistances 8 Flanges 9 Bulk material feed connection 10 Fluidizing gas feed connection 11 Main channel sections

Claims

Device for transporting bulk materials, having a conveying chute (1) which has at least one tubular conveying chute section (2), in which fluidizing gas can be introduced into the lower region of the tube cross section via at least one main channel (3) or main channel section (11) which runs in the longitudinal direction of the conveying chute (1) and gas outlet channels (4) branching off from the latter at intervals, wherein the at least one main channel (3) or main channel section (11) runs outside the conveying chute (1) or the respective conveying chute section (2), wherein the gas outlet channels (4) are designed at least at their gas outlet ends as nozzle tubes (6) branching off from the main channel (3) or the respective main channel section (11), characterized in that, the nozzle tubes (6) are directed at their gas outlet end obliquely downward from the side through the tube wall (5) into the lower region of the conveying channel (1) or of the respective conveying channel section (2).Device according to claim 1, characterised in that each conveying channel section (2) is assigned its own main channel section (11), which can be supplied separately with fluidising gas.Device according to claim 1 or 2, characterised in that two main channels (3) or main channel sections (11) are arranged symmetrically to the vertical longitudinal centre plane of the conveying channel (1) in the upper region of the conveying channel (1).Device according to one of the preceding claims, characterized in that the gas outlet ducts (4) are provided with, in particular adjustable, flow resistances (7) preferably arranged outside the conveying channel (1).Device according to one of the preceding claims, characterized in that the at least one main channel (3) or main channel section (11) is fastened on the outside to the tube wall (5) of the conveying channel (1).Device according to one of the preceding claims, characterized in that the nozzle pipes (6) are positioned at distances of approximately 100 to 400 mm, preferably approximately 150 to 250 mm.Device according to one of the preceding claims, characterized in that the conveying channel (1) or the conveying channel sections (2) is / are inclined.Device according to claim 7, characterised in that the inclination of the conveying channel (1) or of the conveying channel sections (2) is approximately 1 to 20°, preferably approximately 5 to 15°.Device according to one of the preceding claims, characterized in that the conveying channel (1) or the conveying channel sections (2) is / are supported by a steel framework and / or a lining.Device according to one of the preceding claims, characterized in that at least two conveying channel sections (2) are connected to one another in a sealing manner via end-face flanges (8).Device according to one of the preceding claims, characterized in that the nozzle pipes (6) are provided with cleaning and / or hopper openings which are accessible from outside the conveying chute (1).

Images