US20120205007A1

US20120205007A1 - Device for densely loading a divided solid into a chamber

Info

Publication number: US20120205007A1
Application number: US13/395,144
Authority: US
Inventors: Olivier Girard; Romain Vial
Original assignee: Total Raffinage Marketing SA
Current assignee: Total Marketing Services SA
Priority date: 2009-09-09
Filing date: 2010-09-07
Publication date: 2012-08-16
Also published as: FR2949755A1; CA2772819A1; WO2011029815A1; FR2949755B1; CN102712429A; EP2475602A1; BR112012005429A2

Abstract

A device for densely loading a divided solid into a chamber, intended to interact with a divided-solid supply device arranged to release the divided solid above an access to the chamber. The loading device contains a shaft rotated about an axis X1 at an adjustable rotational speed, a plurality of deflecting elements rigidly connected in rotation with the shaft, the deflecting elements having an angle, relative to the shaft, which is separately adjustable from the rotational speed of the latter. According to a preferred embodiment, the shaft is hollow in order to define a passage for the divided solid, at least some of the deflecting element having an end arranged at a distance from the axis X1 that is smaller than the distance separating the axis X1 from the hollow shaft.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a device for densely loading a divided solid into a chamber, intended to interact with a divided-solid supply device designed so as to release the divided solid above an access point to the chamber.
Within the scope of the present disclosure, a divided solid is understood to be a solid in the form of grains or particles, such as, for example, cereal grains in the cereals transportation or storage sector, catalyst pellets in the chemical industry, or fertilizer or wood pellets.
More precisely, the loading device according to the invention is preferably of the type comprising a shaft, driven in rotation about an axis X1 at an adjustable rotational speed, and a plurality of deflecting elements that are integral in rotation with the shaft. Thus, when it falls onto the deflecting elements, the divided solid is deflected so as to be distributed more or less uniformly over the whole surface of the chamber into which it is loaded.

PRIOR ART

Many devices of this type have been disclosed, generally by companies active in the chemical industry, in relation to the loading of chemical reactors with catalyst.
The patent FR 2 431 449 describes an example of a device intended to load chemical reactors with catalyst, comprising a shaft arranged inside a catalyst supply chute, coaxial with the latter. Series of superposed deflecting strip-shaped elements are distributed evenly around the shaft, fixed to the latter by means of couplings that allow the angle defined between the deflecting elements and the shaft to be modified.
The deflecting elements thus move away from the shaft when the latter is driven in rotation, under the effect of centrifugal force, which makes it easier to insert the device into chemical reactors which generally have restricted access. The rotational speed of the shaft can be adjusted in order to control the angle between the deflecting elements and the shaft to take into account the surface area of the reactor to be covered with catalyst.
It should, however, be noted that a change in the rotational speed of the shaft for a given device also entails a change in the permeability of the latter. Consequently, it is not possible to independently adjust the parameters that allow the mode of operation to be adjusted according to the geometry of the chamber to be filled with divided solid.
These devices are thus particularly suited to loading chemical reactors which are generally cylindrical in shape and have a radius of the order of a few meters.
However, these devices are less suited to loading the holds of ships such as bulk carriers. These latter have loading capacities of a different order of magnitude to that of chemical reactors. Indeed, the most common bulk carriers today are Handymax bulk carriers with a capacity of between 35 and 50,000 tonnes, and Panamax bulk carriers with a capacity of between 50 and 80,000 tonnes, whilst Capesize bulk carriers have an even greater capacity.
It should be noted that there are particularly strict regulations on the transportation of cereals by sea. The traditional bulk loading of ships transporting cereals can endanger the stability of the ships when at sea. Even if the hold is completely filled with cargo, the pitching and yawing of the ship when it is sailing cause the grains to settle and create a gap between the bed of grains and the top of the hold. This phenomenon is exacerbated when the hold is not completely filled with cargo.
Even if dockers mechanically level the cargo, this settling when at sea cannot be avoided and can endanger the integrity of the ship, the crew and the cargo. This is because it is a feature of cereal cargoes that they shift easily, like a liquid, as soon as there is a gap between the surface of the grains and the top of the hold.
These movements of the grains resulting from the listing can cause large shifts in the center of gravity of the ship and endanger its stability. Many studies of shipwrecks have shown that a large number of them are the result of this settling phenomenon.
In order to limit this phenomenon, responsible for the capsizing of many ships, the loading of cereals has been subject to special regulations with a view to reducing the risks of the cargo being displaced but which cannot remove these risks altogether. These rules were drawn up by the International Maritime Organization in the 1970s and are collected in the international treaty SOLAS (Safety Of Life At Sea). Chapter VI of this treaty stipulates that grain must be distributed uniformly in holds so that the exposed surfaces are level. The treaty also states that the angle by which the ship lists when the grain is displaced must be no greater than twelve degrees.
Moreover, the devices for loading ships must preferably be able to achieve loading rates of between 600 and 2000 tonnes per hour. The devices mentioned above in connection with the loading of chemical reactors generally do not allow such rates to be achieved.
The devices used today are consequently more basic as they are based simply on the principle of gravity filling, as in the case of loading tubes, conveyor belts, or buckets and require human intervention during and at the end of the loading process to improve the uniformity of the distribution of the grains. Shiploader-type loading devices are also used which allow the flow of grains to be deflected during loading in order to distribute the load throughout the chamber which needs to be filled. However, these shiploaders are not appropriate for the geometries of all the holds of bulk carriers. Furthermore, none of the abovementioned devices allow the density of the loading of the grains to be optimized and hence completely obviate the problem of the stability of the ships.
When catalyst is loaded into a chamber such as a reactor, constraints connected with the anisotropy of the particles of catalyst can result in deviations in the loading profile (appearance of the exposed surface of the catalyst bed, for example the observation of the presence of bumps and craters) from a theoretical flat loading profile.
If the positioning of the particles of catalyst on the surface of the catalyst bed is not homogeneous during loading, this can cause the appearance of the phenomenon of channeling during operation, in other words favored passages which impair the effectiveness of the desired conversion. There may be many consequences, including an increase in the rate of piercing of the catalyst bed, a reduction in the conversion efficiency, a change in the pressure drop, irregularities in the temperature profile during operation, and premature ageing of the catalyst.
As a consequence, a more frequently replacement of the catalyst bed may be observed, as well as an increase of the catalyst costs, of the maintenance costs, of the rate of use of the industrial equipment, and there may be a further economic loss connected with the poor quality of the products resulting from the conversion, the value of said products consequently being reduced. This phenomenon is associated with a more rapid ageing of the equipment, connected with a greater proportion of catalyst fines that will erode the walls of the equipment, cause clogging, and increase the pace of corrosion.

DESCRIPTION OF THE INVENTION

A main object of the present invention is to overcome the disadvantages of the loading devices known from the prior art by providing a dense loading device that offers greater flexibility in the adjustment of the different parameters that affect the quality and uniformity of the distribution of the particles of a divided solid, whilst allowing high loading rates to be achieved.
Another object of the present invention is to optimize the density of the loading, the increased mass transported within a predefined volume having obvious advantages from an economic and environmental point of view.
To this end, the present invention relates more particularly to a device for densely loading a divided solid into a chamber, which has the features mentioned above and also characterized in that its deflecting elements have an angle, with reference to the shaft, that can be adjusted independently of the rotational speed.
By virtue of these features, the device according to the invention has operating conditions which can be adjusted precisely depending on the geometry of the chamber to be loaded, which incidentally makes it possible to meet the required filling conditions for loading bulk carriers and at a sufficient rate.
The device preferably has a shaft which is hollow so as to define a passage for the divided solid, at least some of the deflecting elements having one end arranged at a distance from the axis X1 which is less than the distance separating the axis X1 from the hollow shaft.
The hollow shaft furthermore preferably has a cylindrical general shape that is adapted to interact with a supply chute of the supply device with a cylindrical general shape, and has a radius that is substantially equal to or less than that of the supply chute so as to be able to interact with the latter so that the passage in the shaft is an exclusive passage for the divided solid.
According to a preferred embodiment, the hollow shaft has an opening at its end that is intended to be situated in the vicinity of the chamber, at least some of the deflecting elements having an inner end arranged in the extension of the shaft, opposite its opening.
By virtue of these features, the divided solid can be distributed uniformly over the whole surface of the chamber to be filled, including in the extension of the drive shaft for the deflecting elements.
The density of the loading can thus be optimized. Consequently, the same ship can transport a larger quantity of divided solid on each journey compared with the loading methods from the prior art, affording certain advantages from an economical and environmental point of view.
Moreover, each of the deflecting elements can comprise two substantially plane portions connected to each other such that they have a V shape in cross-section, the plane portions preferably being disconnected in the region of the inner end of each of the deflecting elements so as to define an additional passage for the divided solid. Adjusting means can also be provided to adjust the inclinations of the deflecting elements about a first axis A1 and a second axis A2 which are perpendicular to each other.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will become more apparent on reading the following detailed description of a preferred embodiment, made with reference to the attached drawings, given by way of non-limiting example, in which:

FIG. 1 shows a schematic general view illustrating the principle for loading the hold of a ship with the aid of a loading device according to the present invention;

FIG. 2 shows a schematic perspective view of a loading device according to a preferred embodiment of the present invention, and

FIG. 3 shows a simplified schematic view from above of the loading device in FIG. 2.

EMBODIMENT(S) OF THE INVENTION

FIG. 1 illustrates, by way of non-limiting example and schematically, the principle of the operation of the dense loading device according to the present invention.
The dense loading device 1 is supplied with cereal grains 2 from a primary storage site, through a pipe, generally at a fixed rate, opening out into a chute 3. The use of a conventional buffer hopper between the pipe and the chute can be provided without going beyond the scope of the invention.
The loading device 1, arranged in alignment with the chute 3, comprises a rotating member 4, crammed full of grains from the pipe, having a plurality of openings (described in more detail in relation to FIG. 2) intended to homogeneously distribute the grains over a set of deflecting elements 5.
The stream of grains must preferably be broken up as much as possible in order to optimize the distribution of the grains before they are acted on by the deflecting elements. The grains then fall onto the deflecting elements which, because of their elaborate geometry, separate the grains from one another and distribute them over the whole surface of the chamber which is to be filled, in this case the hold 7 of a ship. The grains are preferably distributed in the hold in the form of a homogeneous “rain” so as to allow the bed of cereal grains to rise evenly over the whole surface of the hold, ensuring that the loading is performed as densely as possible.
When a dense loading is performed, the stable position of each grain is directly linked to the ratio between the flow rate and surface area. The recommended maximum ratio of flow rate to surface area is around 5 tonnes per hour per m². In other words, in order to obtain an optimum loading of the grains, for one hour of loading no more than five tonnes of grains can fall over a 1 m²surface area.
Furthermore, the following additional criteria should also be taken into account in order to optimize the loading.
If slopes appear on the bed of grains during the loading, they should be no greater than 15 degrees. It may be noted that, in the case of a slope of around 37 degrees, the increase in density when comparing bulk loading and loading using a device according to the invention is zero.
It is preferable that the loading can be performed without there being any need for external intervention to level the bed of cereal grains. Indeed, as soon as there is external intervention to level the bed of cereal grains, the bed is dedensified, in other words the density of the loading obtained beforehand is reduced.
It should be possible to optimize the loading rates depending on the surface areas of the holds. It should be possible for them to reach an instantaneous value of the order of 800 tonnes per hour.
To achieve these objectives, the Applicant has developed the dense loading device shown schematically in FIG. 2.
This device comprises a rotating member 4 connected to the chute 3 of the grain-supply device via a cylindrical support 9. The rotating member 4 has the form of a hollow shaft of axis X1 and with a radius that is substantially equal to or less than the radius of the chute 3.
Drive means 10 are provided for driving the hollow shaft 4 in rotation at an adjustable rotational speed. These drive means can take any suitable form known from the prior art. By way of non-limiting example, a motor 12 has been shown in FIG. 2, engaging with a drive belt 13, which may be toothed, that acts on the periphery of the hollow shaft 4 in order to drive it in rotation.
Similarly, the means for connecting the cylindrical support 9 to the chute 3, on the one hand, and the hollow shaft 4 to the cylindrical support 9, on the other hand, can be of any suitable form known from the prior art. It may advantageously be provided that the hollow shaft 4 is mounted rotatably on the cylindrical support 9 by means of a ball or roller bearing (not shown).
The hollow shaft 4 is open at its upper end so that it can receive the grains from the chute 3 and also has an opening 14 at its lower end for pouring the grains into the chamber to be filled.
In the embodiment shown by way of non-limiting example, the hollow shaft 4 carries six series of three superposed deflecting elements 5 (one series being obscured in FIG. 2 for greater clarity), in the form of blades. It appears that the use of eight series can be particularly advantageous in some circumstances, but the variant with six series has been shown for greater clarity in the figures. These series of blades are evenly distributed around the hollow shaft, arranged downstream from the latter. Each blade thus has an inner end 16 arranged at a distance from the axis X1 that is less than the radius of the hollow shaft so that it is placed in the passage for the grains which is defined by the inside of the hollow shaft.
Each series of deflecting elements is advantageously connected mechanically to the hollow shaft from the outside of the latter, so as not to obstruct the passage of the grains.
More precisely, each series of deflecting elements is connected to the hollow shaft by means of a fastening element in the form of an arm 17 which has two portions 19, 20 oriented substantially in the direction of the axis X1 (just one arm 17 has been shown in FIG. 2 for the sake of clarity). One of these portions 19 comprises an adjusting device 22 designed for adjusting its length and so modifying the longitudinal inclination of the corresponding deflecting elements, relative to the axis X1, by rotation about a first axis A1 orthogonal to the latter, the length of the other portion 20 being fixed. The adjusting device 22 can take the form of an actuator or any other suitable form known from the prior art, such as, for example, a worm interacting with an internal screwthread integral with the deflecting elements.
The longitudinal inclination is preferably the same for all the deflecting elements of a same series, or even for all the deflecting elements of all the series.
The second portion 20 can moreover advantageously comprise a knurled part 24 interacting with notched spindles 25 integral with the deflecting elements of a given series and making it possible to modify the transverse inclination of the deflecting elements by the rotation of each of these spindles about an axis A2 orthogonal to the first axis A1.
In the same way as for the longitudinal inclination, the transverse inclination of the deflecting elements is preferably the same for all the deflecting elements of a same series, or even for all the deflecting elements of all the series.
By way of non-limiting example, a motor 26 can be arranged for remote-controlling the rotation of the knurled part 24.
A person skilled in the art will be readily capable of adapting the present teaching for their own purposes by using known alternative means for assembling the deflecting elements on the hollow shaft, without going beyond the scope of the invention.
It is clear from the above that both the longitudinal and transverse orientations of the deflecting elements are independent of the rotational speed of the hollow shaft, which affords great flexibility in adjusting the operation of the dense loading device according to the present invention, depending on the geometrical features of the chamber to be filled and the type of divided solid in question.
It will be noted that the deflecting elements shown in FIG. 2 have a particular preferred form but this is not limiting.
Indeed, each of the deflecting elements has two portions 28 and 29 which are substantially plane and inclined relative to each other so as to have a V shape in cross-section. The portions 28, 29 are furthermore disconnected in the region of the inner end of the corresponding deflecting element so as to define an additional passage 30 so that the divided solid can be poured over each of the deflecting elements of a same series from the element closest to the hollow shaft. By way of example, each portion 28 or 29 can have a trapezoidal shape and be integral with the other portion by way of one of its long sides in the region situated in proximity to the long base, in other words its base furthest from the axis X1.
A person skilled in the art will be readily capable of adapting the form and type of the deflecting elements for their own requirements. They could be made with a rectangular or curved section, from a rigid, semi-rigid, or flexible material without going beyond the scope of the present invention such as, for example and with no limitation being implied, from metal, plastic, rubber, reinforced rubber, or a composite material. It should also be noted that the two portions 28, 29 can be made from different materials depending on the type of divided solid and the geometry of the chamber to be loaded. When the device is used in a maritime context, the selected materials will preferably have appropriate properties to withstand the demanding conditions such as the presence of a large amount of salt.
In order to further improve the quality of the loading, additional adjusting means are preferably provided for adjusting the way in which the particles of divided solid are poured from the hollow shaft 4 in the direction of the deflecting elements 5.
The opening 14 of the hollow shaft can thus advantageously be equipped with means for adjusting its size such as, for example, a diaphragm 32, as can be seen particularly clearly in FIG. 3 which shows the device in FIG. 2 in a schematic view from above.
A person skilled in the art will be readily capable of producing this diaphragm or any other suitable equivalent means. By way of example, the patent application EP 0 482 991 A1 discloses several embodiments of diaphragms.
Returning to FIG. 2, it is clear that the hollow shaft 4 is also equipped with a plurality of lateral openings 34 arranged in alignment with the series of deflecting elements in the direction of the axis X1. The size of the opening of each of these lateral openings 34 can be adjusted by means of a flap 35 with an inclination that can be adjusted independently of that of the other flaps.
By virtue of all of the adjustment features which have just been explained, combined with the special form and distribution of the deflecting elements, the dense loading device according to the present invention affords a very high degree of flexibility so that its operating properties can be adapted according to the geometrical features of the chamber to be filled, and depending on the type of divided solid to be loaded.
Furthermore, the adjustment features make it possible to adjust the operating parameters of the device during loading so as to take into consideration in particular the rising bed of grains. Indeed the higher the bed of grains rises, the shorter the distance that the grains fall becomes, which can require the longitudinal inclination of the deflecting elements to be modified so that they can be raised. In this case, unlike the devices from the prior art, the device according to the invention advantageously allows the longitudinal inclination of the deflecting elements to be modified without modifying their rotational speed.
Experiments undertaken by the Applicant using a device similar to that which has just been described but on a smaller scale found an increase of around 11% in the density of a load of grains of wheat, compared with the density obtained by bulk loading. These results clearly show the advantage of the device according to the invention in terms of safety in the field of cereals transportation and in economic terms given the increase in the load that can be transported in a given volume. As well as the economic advantage that the invention provides, it is also apparent that it is clearly advantageous for the environment that a given ship can transport a larger mass of cereals.
With respect to the use of the dense loading device by the end user, it is possible to provide adjustment data tables that are made available to users to show them how to adjust the different parameters of the device (longitudinal and transverse inclinations of the deflecting elements, sizes of the central 14 and lateral 34 openings) according to the geometry of the chamber to be filled and the exact type of the divided solid to be loaded (taking into consideration in particular the density of a given cereal, for example, as this value also influences the manner in which the loading takes place).
The description above corresponds to a preferred embodiment of the invention, described with no limitation being implied. In particular, the forms shown and described for the different components of the dense loading device are not limiting.
It is, for example, possible to use a solid shaft with a small radius instead of the hollow shaft, whilst ensuring that the longitudinal inclination of the deflecting elements can still be adjusted independently of the rotational speed of the shaft. However, it is preferred to use a hollow shaft as it makes it possible to remove any stress on the passage of the divided solid to be loaded until the latter comes into contact with the deflecting elements. It should also be noted that, because the divided solid flows inside the hollow shaft, a component of rotation can be imparted to the speed of its particles before they fall onto the deflecting elements, so reducing the likelihood of these particles being attritted.
Moreover, a person skilled in the art will be readily capable of adapting the present teaching for their own purposes, in particular by choosing an appropriate number of series of deflecting elements around the shaft (preferably 3, 4, 5, 6, 7, or 8), and an appropriate number of deflecting elements per series (preferably between 1, 2, or 3 or even more than 3).
It is furthermore possible to provide for the adjustments described to be automated without going beyond the scope of the present invention, and to provide video means for monitoring the progress of the loading and means for collecting dust produced during loading, such as for example a device for spraying a fine mist of water droplets in proximity to the openings of loading device.
As mentioned above, it will be noted that the invention can also be applied in the oil, chemical and pharmaceutical industries, for loading grains of, for example, catalyst into a chamber such as a reactor.

Claims

1. A device (1) for densely loading a divided solid (2) into a chamber (7), intended to interact with a divided-solid supply device (3) designed so as to release said divided solid into said chamber in the form of a homogeneous rain distributed over the whole surface of said chamber, the loading device comprising

a shaft (4) driven in rotation about an axis Xl at an adjustable rotational speed,

a plurality of deflecting elements (5) that are integral in rotation with said shaft, characterized in that said deflecting elements have an angle, with reference to said shaft, that can be adjusted independently of said rotational speed.

2. The device (1) as claimed in claim 1, characterized in that said shaft (4) is hollow so as to define a passage for said divided solid (2), and in that at least some of said deflecting elements (5) have an end (16) arranged at a distance from said axis X1 that is less than the distance separating said axis X1 from said hollow shaft.

3. The device (1) as claimed in claim 2, characterized in that said hollow shaft (4) has a cylindrical general shape that is adapted to interact with a supply chute (3) of the supply device with a cylindrical general shape, and has a radius that is substantially equal to or less than that of the supply chute so as to be able to interact with the latter so that said passage is an exclusive passage for said divided solid.

4. The device (1) as claimed in claim 2, characterized in that said hollow shaft (4) has an opening (14) at its end that is intended to be situated in the vicinity of said chamber (7), and in that at least some of said deflecting elements (5) have an inner end (16) arranged in the extension of said shaft, opposite said opening.

5. The device (1) as claimed in claim 4, characterized in that it comprises an adjusting member (32) for said opening (14).

6. The device (1) as claimed in claim 5, characterized in that said adjusting member (32) is a diaphragm.

7. The device (1) as claimed in claim 4, characterized in that said hollow shaft (4) also has a plurality of lateral openings (34) arranged in alignment with said deflecting elements (5) in the direction of said axis X1.

8. The device (1) as claimed in claim 4, characterized in that it comprises a plurality of fastening elements (17) for the deflecting elements (5), each of which is connected to the periphery of said hollow shaft (4), on the one hand, and to a portion of one of said deflecting elements which is not said inner end (16).

9. The device (1) as claimed in claim 8, characterized in that each of said fastening elements (17) has an adjustable length.

10. The device (1) as claimed in claim 1, characterized in that each of said deflecting elements (5) has two substantially plane portions (28, 29) connected to each other so as to have the shape of a V in cross-section.

11. The device (1) as claimed in claim 10, characterized in that said plane portions (28, 29) are disconnected in the region of the inner end (16) of each of said deflecting elements (5) so as to define an additional passage (30) for said divided solid (2).

12. The device (1) as claimed in claim 1, characterized in that it comprises at least one first member (22) for adjusting the inclination of said deflecting elements (5) about a first axis of rotation A1 orthogonal to said axis X1.

13. The device (1) as claimed in claim 12, characterized in that it comprises at least one second member (24) for adjusting the inclination of said deflecting elements (5) about a second axis of rotation A2 orthogonal to said first axis of rotation A1.

14. The device (1) as claimed in claim 1, characterized in that said deflecting elements (5) are arranged in series of deflecting elements superposed one above the other, said series being evenly distributed around said hollow shaft (4).

15. The device (1) as claimed in claim 14, comprising at least one first member (22) for adjusting the inclination of said deflecting elements about a first axis of rotation A1 orthogonal to said axis X1, characterized in that said first member (22) acts in a similar and simultaneous manner at least on all of the deflecting elements (5) forming part of the same series.

16. The device (1) as claimed in claim 15, comprising at least one second member (24) for adjusting the inclination of said deflecting elements (5) about a second axis of rotation A2 orthogonal to said first axis A1, characterized in that said second member (24) acts in a similar and simultaneous manner at least on all of the deflecting elements (5) forming part of the same series.