Fluent material handling – with receiver or receiver coacting mea – Multiple passage filling means for diverse materials or flows – With baffle – spreader – displacer – drip ring – filter or screen
Reexamination Certificate
2002-01-02
2002-09-03
Douglas, Steven O. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Multiple passage filling means for diverse materials or flows
With baffle, spreader, displacer, drip ring, filter or screen
C239S688000, C414S301000
Reexamination Certificate
active
06443193
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a device for dispersing a divided solid material, particularly in the form of granules or rods, inside a receptacle such as a tank.
DESCRIPTION OF THE RELATED ART
The invention finds a particularly advantageous application in the petrochemical industry, for filling reactors with catalyst material, but could be used for filling any type of receptacle with any type of divided solid material provided that the bed of material deposited in this receptacle has to be flat, uniform and/or dense, and provided that filling has to be performed with a limited emission of dust. The invention could thus, for example, be used for filling grain silos.
In the field of the petrochemical industry, it is commonplace for fluids to be treated by passing these fluids through a bed of catalyst material. This catalyst material is in the form of rods a few millimeters long placed inside the tank of the reactor which is generally of cylindrical shape.
One method of charging such a reactor consists in purely and simply tipping the catalyst material into the tank. This material does, however, have the disadvantage of depositing itself in the form of a more or less conical heap, the compaction of which is far greater in the central part than in the peripheral parts. The result of this is that the fluid to be treated tends to prefer to pass through the thinner and less dense layers, which appreciably reduces the efficiency of the reactor.
In addition, the catalyst material is frequently based on alumina, and is therefore friable and prone to breaking up. The rods of which it is made break up to some extent as they are being tipped out, which lessens the efficiency of the treatment and leads to a significant loss of material through the emission of dust.
Furthermore, the amount of material that can be placed in the reactor is reduced.
Another filling technique consists in providing, at the outlet of the conduit used for introducing the material into the tank, a dispersing head comprising plates or blades driven in rotation, which break up the stream of material.
This kind of head improves the distribution of product in the tank, without, however, making it possible to obtain a perfectly uniform bed of material. What happens is that dispersion adopts highly random paths, and the rods often reach the peripheral wall of the tank before reaching the bottom of this tank, and therefore tend to accumulate as a matter of preference at the base of this wall. The result of this is that the upper face of the bed obtained is more or less in the shape of a conical dish, also creating passages that the fluid that is to be treated prefers to take.
Furthermore, the rods strike the plates or blades, and this causes damage to them and the emission of abundant quantities of dust.
Certain problems in regulating the rate of flow of the material arise, and the density of the bed obtained is not very high.
SUMMARY OF THE INVENTION
The present invention sets out to overcome all these drawbacks by providing a dispersing device that makes it possible to deposit the material in the form of a flat, uniform bed of high density without the risk of damaging the granules or rods that make up this material, and with limited emissions of dust.
The device to which it relates comprises, in a way known per se, an element driven in rotation about a vertical axis, placed at the outlet of the duct for introducing divided solid material into the receptacle.
According to the invention, this element comprises two conduits for dispersing the material, each having a curved shape and an opening through which the material can flow out into the receptacle; these conduits are curved about one and the same axis perpendicular to the axis of rotation of said dispersing element but in opposite directions from each other, and are shaped in such a way that their outflow openings are each positioned on one side of the axis of rotation of said dispersing element, more or less in one and the same diametral plane, and are directed in opposite directions; each of these conduits furthermore comprises at least one longitudinal partition extending over all or over a large part of its length, this partition being capable of splitting the stream of material and of distributing the flow thereof, against centrifugal force, over all or over a large part of the outflow opening.
As a result their aforementioned curved shape, these conduits eliminate any impact of the material as it flows and, when the element is driven in rotation, allow the material to be sprayed out in two helical streams in opposite directions, the width of which more or less corresponds to the radius of the receptacle that is to be filled. The speed of rotation of the dispersing element may be regulated, as a function of the type of material, of the outflow speed thereof and of the distance separating this element and the bottom of the receptacle or the surface of the material, so that the granules or rods situated on the outside of these streams drop more or less to the base of the side wall of the receptacle.
A more or less flat bed of material with uniform compaction is thus obtained, without damage to the granules or rods or emission of dust.
The cross section of the conduits may be relatively small so that the two helical streams spread a relatively limited amount of this material on each revolution of said element, and the speed of rotation of said element may, by contrast, be relatively high. A bed of very high density is thus obtained without this in any way affecting the speed with which the receptacle is filled, given said speed of rotation.
As a preference, the distance between axes of two adjacent partitions increases from that part of each opening that lies on the same side as the axis of rotation of the dispersing element toward that part of the same opening that lies on the opposite side. This positioning of the partitions allows better distribution of the material within the stream emitted by the conduit.
According to a preferred embodiment of the invention, each conduit has a shape more or less in the form of half a helicoid turn. This particular shape has in the past yielded excellent results.
Advantageously, the dispersing element comprises additional means allowing the flow of the material to be regulated, such as position-adjustable plates, situated at the level of the conduits so as to increase or decrease the cross section of these conduits, or situated facing the openings of these conduits. The plates situated facing the openings of the conduits may have inclined edges capable of suitably deflecting the stream of material slightly in the vertical plane, if necessary.
As a preference, the device according to the invention comprises a system for sucking up the dust of the divided solid material, acting inside the receptacle that is to be filled and/or inside the device itself.
BRIEF DESCRIPTION OF THE DRAWINGS
For a good understanding thereof, the invention is described once again hereinbelow with reference to the appended schematic drawing which, by way of non-limiting example, depicts one preferred embodiment of the dispersion device to which it relates.
FIG. 1
is a simplified part view in longitudinal section of a reactor which can be used in the field of the petrochemical industry;
FIG. 2
is a view in longitudinal section of the device according to the invention;
FIG. 3
is a perspective view of the dispersing element that this device comprises; and
FIG. 4
is a view of this element in section on the line IV—IV of FIG.
2
.
REFERENCES:
patent: 1065960 (1913-07-01), Murray
patent: 4397423 (1983-08-01), Beaver et al.
patent: 4437613 (1984-03-01), Olson
patent: 331 714 (1976-08-01), None
patent: 2 766 386 (1999-01-01), None
Cantor & Colburn LLP
Douglas Steven O.
LandOfFree
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