US3543414A

US3543414A - Gas treatment apparatus

Info

Publication number: US3543414A
Application number: US794676*A
Authority: US
Inventors: Claude Gomarin
Original assignee: Tunzini Ameliorair SA
Current assignee: Tunzini Ameliorair SA
Priority date: 1968-02-13
Filing date: 1969-01-28
Publication date: 1970-12-01
Anticipated expiration: 1987-12-01
Also published as: GB1260389A; DE6905710U; FR1564658A; ES363900A1

Description

S U T A m mw RA AT M m wm m cm. s A G Dec. l, 1970 3 Sheets-Sheet l Filed Jan. 28, 1969 nella" Dec. l, 1970 Filed Jan. 28. 1969 cz, GOMARIN GAS TREATMENT APPARATUS C5` Sheets-Sheet 2 Dec., l, 197@ Q. GQMARIN m @As TREATMENT APPARATUS Filed Jan. 28, 1969 asheets-sheet s United States Patent O 3,543,414 GAS TREATMENT APPARATUS Claude Gomarin, Champigny-sur-Marne, France, assigner to Tunzini Ameliorair, Paris, France Filed Jan. 28, 1969, Ser. No. 794,676 Claims priority, application France, Feb. 13, 1968,

Inf. (31.152611 9/08 U.S. Cl. 34-164 14 Claims ABSTRACT F THE DISCLOSURE This invention relates to apparatus for the treatment, by a gaskcalled hereafter treatment gas-of a fragmented material, that is to say of a material divided into solid constituent parts, of determined average dimensions, called hereafter fragments Such apparatus comprises, firstly, a treatment enclosure having a bottom-called hereafter Solal-disposed at least approximatively horizontally, and constituted by a wall having a multiplicity of orices distributed over practically all of its surface, the material to be treated resting on this sole, secondly, feed means for generating a flow of treatment gas, which flow is brought below the sole and is characterized by a owrate and a pressure such that the treatment gas is distributed by the sole into the midst of the fragmented material with a speed-called hereafter fluidization speedcapable of causing and maintaining the fluidization of the fragmented material resting on this sole, and thirdly, motor means for subjecting the sole to mechanical vibrations in the vertical direction and whose purpose is to hinder the agglomeration of several fragments of the material among themselves to form an agglomerate greater in mass and in volume than the initial fragments, such an agglomerate being apt to hinder the fluidization partially or totally, and consequently, to stop the treatment partially or totally.

This invention is concerned more particularly, but not exclusively, with apparatus of this type in lwhich the treatment of the fragmented material consists of a drying by a hot treatment gas or of a cooling by a cold treatment gas.

ln such apparatus, a dimension is generally adopted, for the smallest dimension of the orifices of the sole, which is greater than the average dimension of the fragments of the material to be treated, in order to avoid the risk of clogging of these orifices by exceptional fragments having dimensions smaller than the average dimension, or by parts of broken fragments, or by dust.

It will be appreciated that the sole, which is subjected to mechanical vibrations, has a tendency to behave like a sieve, and that a part of the material being treated is lost since it passes below the sole.

A conventional sole constituted by a perforated sheet of thickness e and subjected to vibrations of amplitude A moves vertically through a distance 2A which, in apparatus known hitherto, is considerably greater than the thickness e of the perforated sheet constituting the sole. Consider then a fragment of material which, at an instant corresponding to the lower extreme position of the sole, is located at the level of an orifice. This fragment is then subjected to an aerodynamic force directed towards the ice top which is greater than its weight. At the following instant, corresponding to the upper extreme position of the sole, this same fragment will not have substantially changed its absolute position, but it will then be located below the sole in a region where it is subjected to an aerodynamic force directed towards the top which is smaller than its weight, this fragment being accordingly irremediably lost since it fall towards the lower part of the apparatus under its own weight.

To remedy the disadvantage constituted by this sieve effect, it has been proposed to constitute the sole by two perforated sheets whose orifices are disposed in quincunx, that is to say in staggered rows, these two sheets being maintained one with respect to the other at a distance such that the flow of treatment gas between the adjacent faces of these two sheets brings back above the upper perforated sheet the fragments which are located on the lower perforated sheet after having passed through the orifices of the upper perforated sheet.

Such a sole gives full satisfaction with regard to the absence of sieving, but it has the disadvantage of becoming deformed as soon as the temperature reaches a few hundreds of degrees centigrade for the lower perforated sheet is brought to a temperature notably different from the temperature of the upper perforated sheet.

In particular, in the case of an apparatus for drying a fragmented product, the lower perforated sheet-in contact with the hot treatment gasis brought to a higher temperature than the temperature of the upper perforated sheet-in contact with the material to be dried.

Conversely, in the case of an apparatus for cooling a fragmented product, the lower perforated sheet-in contact with the cold treatment gas-is brought to a lower temperature than the temperature of the upper perforated sheetin contact with the material to be cooled.

An object of this invention is to provide apparatus of the type in question which fulfills the requirements of practice, and in particular which mitigates the disadvantage constituted by the sieve effect, and whose sole can be subjected to differences of temperature between the lower face and the upper face without undergoing large deformations.

According to the principal feature of this invention, in an apparatus of the type in question, each of the orices comprised by the sole is constituted by the upper opening of a conduit which extends down from the level of the sole and whose axial length L, counted between its upper opening and its lower opening, is at least equal to, and preferably slightly greater than, the distance 2A which separates the lower extreme position and the upper extreme position that the sole occupies alternately under the effect of the mechanical vibrations to which the sole is subjected, these conduits being disposed, with respect to the level of the sole, so as to be in contact with the treatment gas along practically all their exterior wall.

With regard to the sieve effect of such a sole, it will be appreciated that it is practically entirely eliminated for a fragment of material which, at an instant corresponding to the lower extreme position of the sole, is located at the level of an orifice constituted by the upper opening of a conduit-this fragment then being subjected to an aerodynamic force directed towards the top and greater than its weight-is located, at the instant corresponding to the upper extreme position of the sole, in the conduit considered-this fragment then being still subjected to an aerodynamic force greater than its weight.

With regard to the deformations of such a sole due to temperature gradients between its lower face and its upper face, it will be appreciated that they are substantially diminished, since the only parts of the sole which are subjected to these temperature gradients are the parts joining together two successive orifices, hence parts of very small dimensions with respect to the overall dimensions of the sole; moreover, the conduits corresponding to each of the orifices can contribute towards ensuring the rigidity of the sole.

The invention comprises, apart from this principal feature, certain other features which are preferably used at the same time, and which will be more explicitly described hereafter.

In any case, the invention will be well understood from the following complementary description as well as from the accompanying drawings, which complementary description and drawings are given merely by way of example.

FIG. l, of these drawings, is a schematic cross-section of an apparatus established according to the invention;

FIGS. 2 and 3 show in detail a part of the sole of an apparatus according to the invention, this sole lbeing shown in its lower extreme position in FIG. 2 and in its upper extreme position in FIG. 3;

FIG. 4 shows a cross-section on a larger scale of a part of the sole of an apparatus according to the invention, this sole being established according to a first embodiment;

FIG. 5 is a perspective View of an element of the sole shown in FIG. 4;

FIGS. 6 and 7 show respectively, in the same conditions as FIG. 4, two modifications of another embodiment of the sole of an apparatus according to the invention; and

FIG. 8 shows, still in the same conditions as in FIG. 4, still another embodiment of the sole of an apparatus according to the invention.

The apparatuses which will now be described with reference to the drawings, are apparatuses for the drying, by a hot treatment gas, of a fragmented material.

As shown in FIG. 1, such apparatus comprises:

A treatment enclosure 1 having a sole 2 constituted by a wall having a multiplicity of orifices 3 distributed over practically all of its surface, the material to be treated M resting on this sole 2 which is disposed horizontally, approximatively at least,

Feed means 4 for generating a ow of treatment gas, which flow is brought, after having been previously heated by heating means 5, below the sole 2, this flow being characterized by a fiow-rate and a pressure such that the treatment gas is distributed by the sole 2 into the midst of the fragmented material M with a speed of fiuidization, that is to say a speed capable of causing and maintaining the fluidization of the fragmented material M resting on this sole 2, and i Motor means 6 for subjecting the sole 2 to mechanical fvibrations in the vertical direction and whose frequency and amplitude are such that they hinder the agglomeration of several fragments of the material M among themselves to form an agglomerate greater in mass and in volume than the initial fragments, such an agglomerate being apt to hinder the fluidization partially or totally, and consequently, to stop the treatment partially or totally.

In an apparatus of this type, the fragmented material M thus fluidized behaves as a fluid, and this material can thus be introduced through an introduction spout 7 at one of the ends of the sole 2 and can flow out, in the direction indicated by the arrow D, over a sill 8, preferably adjustable, disposed at the other end of the sole 2.

The disadvantages of apparatuses of this type known hitherto are constituted, as recalled in detail in the introduction of this text:

By the sieve effect due to the sole which is subjected to mechanical vibrations, and

By the risk of deformation of the sole whose lower face-in contact with the hot treatment gas-is brought to a higher temperature than the temperature of its upper face-in contact with the material M t0 be, dried This being the case, according to the principal feature of the invention, which has for its chief object the reduction of the sieve effect and the reduction of the deformations of the sole, each of the orifices 3 comprised by the sole 2 is constituted by the upper opening of a conduit 9 which extends down from the level of the sole 2 and whose axial length L, counted between its upper opening and its lower opening, is at least equal to, and preferably slightly greater than, the distance 2A which separates the lower extreme position and the upper extreme position that the sole 2 occupies alternately under the effect of the mechanical vibrations to which this sole 2 is subjected, these conduits 9 being disposed with respect to the level of the sole 2 so as to be in contact with the treatment gas along practically all their exterior wall.

With regard to the sieve effect of such a sole, it will be appreciated, as explained hereafter, that it is practically entirely eliminated.

Consider a fragment m which, at an instant corresponding to the lower extreme position of the sole 2 (FIG. 2) is located at the level of an orifice 3 constituted by the upper opening of a conduit 9, this fragment m is then subjected to an aerodynamic force F directed towards the top which is greater than its weight P. At the following instant corresponding to the Iupper extreme position of the sole 2 (FIG. 3), this same fragment m will not have substantially changed its absolute position, it will be located below the sole 2, in the conduit 9 considered, and it will still be subjected to an areodynamic force F directed towards the top and which is greater than its Weight P.

With regard to the deformations of such a sole 2 due to temperature gradients between its lower face and its upper face, it will be appreciated that they are substantially decreased since the only parts of the sole 2 which are subjected to these temperature gradients are the parts 10 joining together two successive orifices 3. These parts 10 have very small dimensions with respect to the overall dimensions of the sole 2. Moreover, the conduits corresponding to each orifice 3 contribute towards ensuring the rigidity of the sole 2.

According to the embodiments of the invention illustrated respectively in FIGS. 4 and 5 and in FIGS. 6 and 7, each conduit 9, whose upper opening constitutes one of the orifices 3 comprised by the sole 2, is constituted by the adjacent faces of two channel bars 11 of upside down U cross-section, the sole 2 being th-us constituted by a plurality of channel bars 11 disposed parallel to each other with a pitch S.

This pitch S is equal to the sum of the separation n existing between each channel bar 11 and of the Width r of each channel bar 11.

The separation n, which constitutes the smallest dimension of the orifice 3, is determined as a function of the average dimension of the fragments of the material to be treated.

The ratio n/s, which is equal to the ratio between the cross-section for the passage of the treatment gas through the sole 2 and the total cross-section of the sole 2, is determined as a function of the speed of fluidization of the fragmented material M to be treated.

Preferably, the channel bars 11 are oriented perpendicular to the direction D along which the fiuidized fragmented material M fiows.

According to the embodiment illustrated in FIGS. 4 and 5, the two wings of each channel bar 11 are extended towards the bottom respectively by two extensions 12 bent towards the longitudinal plane of symmetry of the channel bar 11 considered, such extensions 12 contributing towards increasing the rigidity of each channel bar 11 and favouring the fiow of the treatment gas `from below the sole 2 into the conduits 9.

As shown in FIG. 5, the sole 2 can then be constituted by a succession of channel bars 11, inserted, either individually, or by prefabricated groups of channel bars, into two horizontal slideways 13, each channel bar 11 being provided with distance pieces 14 fixing its separation n.

In these conditions, it is advantageous to provide the two ends of each channel bar 11, in the region where these two ends cooperate with the two horizontal slideways 13, with added members interconnecting the two wings of the channel bar 11 along an axial length corresponding to the depth of the horizontal slideways 13. Such added members 15 can advantageously be constituted by a section of channel bar identical to the channel bar 11 and spot welded on the external face of one of the wings and on the internal face of the other Wing of the channel bar 11.

When an apparatus comprising a sole 2 established according to the embodiment illustrated in FIGS. 4 and 5 ceases to operate, a certain quantity of the fragmented material M which remains on this sole 2 passes irremediably through the sole 2 and accumulates in the lower part of the apparatus.

In certain cases, during the restarting of the apparatus, this material can be reinjected into the treatment enclosure 1, on condition that this material has remained in fragmented form.

Nevertheless, and still in the case in which the material can remain-at least a certain time-in fragmented form, the embodiment illustrated in FIGS. 6 and 7 can be used, which has precisely for its object the avoidance of the accumulation of fragmented material M in the lower part of the apparatus during periods of non-operation of the apparatus.

According to this embodiment, one of the two wings of each channel bar 11, always the same Wing, is extended towards the bottom by one branch of a right angled extension 16 whose other branch extends horizontally at least as far as the level of the wing of the adjacent channel bar 11, which wing is not provided with such an extension.

The vertical dimension of this extension 1-6 is such that the height h of the passage defined by the upper face of the horizontal branch of the extension 16 and by the lower end of the wing of the adjacent channel bar 11 is sufficiently small so that the speed of the treatment gas in this passage causes the blowing of the particles of `fragmented material M which can have accumulated on this upper face vertically in line with each orifice 3, during periods of non-operation of the apparatus.

Generally the blowing can be caused by a speed practically equal to the speed of the treatment gas in the conduit 9. In these conditions, the height h can be equal, approximately at least, to the separation n between two adjacent channel bars 11.

As for the length of the horizontal branch of this extension 16, it is s-uch that this horizontal branch extends beyond the wing of the adjacent channel bar 11 by a value t which depends on the form taken by the flank of the heap constituted by the particles of fragmented' material M accumulated on the upper face of the horizontal branch of the extension 16. If it is considered, which is generally the case, that the flank of the heap is inclined at 45, the value of t must be equal to and preferably slightly greater than the value of h.

According to the modification of this embodiment shown in FIG. 6, the extension 16 is provided on the wings of the channel bars 11 which are remote from the region of the introduction of the treatment gas under the sole 2. Such a disposition creates a large pressure drop which can improve the distribution of the treatment gas below the sole 2, in particular in the case of a low speed of fluidization.

According to the modification of this embodiment shown in FIG. 7, the extension 16 is provided on the wings of the channel bars 11 which are near to the region of the introduction of the treatment gas under the sole 2. Such a disposition decreases the pressure drops. 'Ihe horizontal branch of the extension 16 can advantageously comprise a part in the form of a deflector 17, bent towards the bottom, favouring the passage of the treatment gas into the sole 2.

According to the embodiment illustrated in FIG. 8, each conduit 9, whose upper opening constitutes one of the orifices 3 comprised by the sole 2, is constituted by a tube 18, advantageously of circular cross-section. The sole 2 is then constituted by a sheet 19 provided with holes 20 of diameter equal to the exterior diameter of the tubes 18, each of these tubes 18 being inserted in this sheet 19.

The interior diameter d of each of these tubes 18, which constitutes the smallest dimension of the orifice 3, is determined as a function of the average dimension of the fragments of the material to be treated.

The number of orifices 3, which conditions the ratio between the cross-section for the passage of the treatment gas through the sole 2 and the total cross-section of the sole 2, is determined as a function of the speed of fluidization of the fragmented material M to be treated.

Preferably, the holes 20 provided in the sheet 19 are disposed in quincunx.

There can then be provided, towards the lower part of the conduits 9 thus realized, connection elements 21 rigidly secured to a series of aligned tubes 18, such connection elements 21 contributing towards increasing the rigidity of the sole 2.

An apparatus for the drying of a fragmented material, according to the present invention, has a certain number of advantages of which the principal ones are summarized by the following points:

Practically total elimination ofthe sieve effect of the sole,

Substantial decrease of the deformations of the sole,

Possibility of effecting the drying at high temperature,

Facility of assembling and dismantling of the sole,

No passage of the fragmented material below the sole during periods of non-operation.

What I claim is:

1. Apparatus for the treatment by a gas of a fragmented material, comprising:

a treatment enclosure having a sole disposed at least approximatively horizontally and constituted by a wall having a multiplicity of orifices distributed over practically all of its surface, whereby the material to be treated can rest on this sole;

feed means for generating a ow of treatment gas,

which flow is brought below the sole and is characterized by a flow-rate and a pressure such that the treatment gas is distributed by the sole into the midst of the fragmented material with a speed capable of causing and maintaining the fluidization of the fragmented material resting on this sole; and

motor means for subjecting the sole to mechanical vibrations in the vertical direction so as to hinder the agglomeration of several fragments of the material among themselves to form an agglomerate greater in mass and in volume than the initial fragments, such an agglomerate being apt to hinder the fluidization at least partially, and consequently, to stop the treatment at least partially;

wherein the improvement resides in the fact that each of said orifices comprised by the sole is constituted by the upper opening of a conduit which extends down from the level of the sole and whose axial length, counted between its upper opening and its lower opening, is at least equal to the distance which separates the lower extreme and upper extreme positions that the sole occupies alternately under the effect of the mechanical vibrations to which said sole is subjected, these conduits being disposed with respect to the level of the sole so as to be in contact with the treatment gas along practically all their exterior Wall.

2. Apparatus according to claim 1, wherein the axial length of each said conduit, counted between its upper opening and its lower opening, is slightly greater than the 7 distance which separates the lower extreme and upper extreme positions that the sole occupies alternately under the effect of the mechanical vibrations to which said sole is subjected.

3. Apparatus according to claim 1, wherein each conduit whose upper opening constitutes one of the orifices comprised by the sole is constituted by the adjacent faces of two channel bars of upside down U cross-section, the sole being thus constituted by a plurality of channel bars disposed parallel to each other.

4. Apparatus according to claim 3, including introduction means for introducing the fragmented material at one end of the sole and outlet means for the outlet of the fragmented material at the other end of the sole, whereby the fluidized fragmented material flows from the introduction means towards the outlet means, wherein the channel bars are oriented perpendicular to the direction along which the uidized fragmented material flows.

5. Apparatus according to claim 3, wherein the two wings of each channel bar are extended towards the bottom respectively by two extensions bent towards the plane of longitudinal symmetry of the channel bar considered.

6. Apparatus according to claim 3, wherein the sole is constituted by a succession of channel bars inserted into two horizontal slideways, each channel bar being provided with distance pieces xing its separation.

7. Apparatus according to claim 6, wherein the two ends of each channel bar are provided, in the region where these two ends cooperate with said two horizontal slideways, with added members interconnecting the two wings of the channel bar along an axial length corresponding to the depth of said horizontal slideways.

8. Apparatus according to claim 7, wherein said added members are constituted by a section of channel bar identical to the channel bar whose two wings it is interconnecting, said section of channel bar being spot welded on the external face of one of the wings and on the internal face of the other wing of the channel bar whose two Wings it is interconnecting.

9. Apparatus according to claim 3, wherein one of the two wings of each channel bar, always the same wing,

is extended towards the bottom by one branch of a right angled extension whose other branch extends horizontally at least as far as the level of the wing of the adjacent channel bar, which wing is not provided with such an extension.

10. Apparatus according to claim 9, wherein said other branch of each right angled extension extends horizontally beyond the level of the wing of the adjacent channel bar, which wing is not provided with such an extension.

11. Apparatus according to claim 9, wherein the eX- tensions are respectively provided on the channel bar wings that are remote from the region of the introduction of the treatment gas under the sole.

12. Apparatus according to claim 9, wherein the extensions are respectively provided on the channel bar wings that are near to the region of the introduction of the treatment gas under the sole.

13. Apparatus according to claim 1, wherein each conduit whose upper opening constitutes one of the orifices comprised by the sole, is constituted by a tube, the sole being constituted by a sheet provided with holes of diameter equal to the exterior diameter of the tubes which are then inserted in this sheet.

14. Apparatus according to claim 13, wherein the tubes are aligned, and the lower parts of each line of tubes are interconnected by a connection element.

References Cited UNITED STATES PATENTS 2,715,565 8/1955 McKay. 2,850,808 9/1958 Jones et al. 2,876,557 3/1959 Ducatteau 34-164 XR 2,934,411 4/1960; Purse. 3,173,768 3/1965 Witte 34-164 3,254,428 6/1966 Bates 34-164 FREDERICK L. MATTESON, JR., Primary Examiner R. A. DUA, Assistant Examiner U.S. Cl. X.R. 34-57