Separating particles from a processing gas stream

Abstract

A separator for separating solid particles from a processing gas stream that has been fed repeatedly through a work machine, wherein the separator includes a processing gas inlet through which particle-laden processing gas emitted from the work machine is fed into the separator, and a filterless separator element to reduce the particle content of the processing gas and a processing gas outlet to discharge the processing gas with its reduced particle content to the work machine, the separator including a secondary stream filter, which filters a smaller portion of the processing gas, and a secondary outlet, connected thereto, which ejects the filtered secondary stream of processing gas.

Claims

1. A separator for separating solid particles from a processing gas stream that has been fed repeatedly through a work machine, the separator comprising: a processing gas inlet through which particle-laden processing gas emitted from the work machine is fed into the separator, a filterless separator element to reduce a particle content of the processing gas, and a processing gas outlet to discharge a portion of the processing gas with the reduced particle content to the work machine, wherein the separator includes a secondary stream filter and a secondary outlet downstream from the secondary stream filter, the secondary stream filter filtering another portion of the processing gas with the reduced particle content to provide a filtered secondary stream, and the secondary outlet ejecting the filtered secondary stream of the processing gas, wherein the separator element comprises a cyclone separator and a baffle connected to the cyclone separator downstream from said cyclone separator, wherein a tube with a front-end inlet opening is provided as the baffle, said tube being positioned as an immersion tube in an area of an eye of a cyclone stream, and wherein the immersion tube passes through the cyclone stream.

2. The separator according to claim 1, wherein the filterless separator element is situated upstream from the secondary stream filter in such a way that the secondary stream filter is fed with processing gas bearing reduced particle content.

3. The separator according to claim 1, wherein a lower front end of the immersion tube comprises the front-end inlet opening, wherein within an interior of the immersion tube, the immersion tube is configured to project a stream rising along a longitudinal axis of the immersion tube, and wherein the separator is configured in such a way that the cyclone stream provides a falling stream between the processing gas inlet and the lower front end of the immersion tube.

4. The separator according to claim 3, wherein where the immersion tube provides the baffle, the immersion tube is configured in several parts so that the front-end inlet opening is configured from an immersion-tube end piece, which is removable from a remainder of the immersion tube, and wherein the immersion-tube end piece is exchangeable with another immersion-tube end piece, which comprises a front-end inlet opening with a different diameter.

5. The separator according to claim 1, wherein the immersion tube branches into a first branch, which configures the processing gas outlet, and into a second branch, which forms the secondary outlet, such that an end of the first branch is situated below an end of the second branch.

6. The separator according to claim 5, wherein the immersion tube contains in the second branch the secondary stream filter upstream from the secondary outlet, and wherein the secondary stream filter is configured as a filter tube, with a vertically directed tube longitudinal axis, of which a coating surface is penetrated by the secondary stream from outside to inside.

7. The separator according to claim 6, wherein the secondary stream is fed to the secondary stream filter through a gap between the immersion tube and the filter tube.

8. The separator according to claim 1, wherein the separator is equipped with a suction pump, which applies a low pressure to the secondary outlet or the second branch.

9. The separator according to claim 8, wherein the separator is equipped with the suction pump behind the secondary outlet.

10. The separator according to claim 1, wherein the separator comprises a dust-removal or flushing device configured to flush the filter in a direction counter to a filtering direction.

11. The separator according to claim 10, wherein the filter is flushed by pressure surges.

12. The separator according to claim 1, wherein the immersion tube contains the secondary stream filter for the secondary outlet.

13. The separator according to claim 1, wherein the secondary stream filter mounted upstream from the secondary outlet is positioned in such a way that particles removed by the secondary stream filter are evacuated during flushing through the immersion tube downward into a particle discharge area.

14. The separator according to claim 1, wherein a cyclone sheath tube widens above the baffle and narrows again at the level of the baffle.

15. A system comprising: a mill or crushing machine, and a separator connected by tubing to the mill or crushing machine, the separator being configured to remove dust from a processing gas in the mill or crushing machine, wherein the separator includes: a processing gas inlet through which particle-laden processing gas emitted from the mill or crushing machine is fed into the separator, a filterless separator element to reduce a particle content of the processing gas, and a processing gas outlet to discharge a portion of the processing gas with the reduced particle content to the mill or crushing machine, wherein the separator includes a secondary stream filter and a secondary outlet downstream from the secondary stream filter, the secondary stream filter filtering another portion of the processing gas with the reduced particle content to provide a filtered secondary stream, and the secondary outlet ejecting the filtered secondary stream of the processing gas, wherein the separator element comprises a cyclone separator and a baffle connected to the cyclone separator downstream from said cyclone separator, wherein a tube with a front-end inlet opening is provided as the baffle, said tube being positioned as an immersion tube in an area of an eye of a cyclone stream, and wherein the immersion tube passes through the cyclone stream.

16. A method for separating solid particles from a processing gas stream, which issues from a work machine, the method comprising: feeding particle-laden processing gas from the work machine to a separator via a processing gas inlet, subjecting the processing gas to a filterless separator element of said separator to reduce a particle content of the processing gas, dividing the processing gas with the reduced particle content into a first part and a second part, discharging the first part via a processing gas outlet of said separator and feeding back the first part, unfiltered, to the work machine, and filtering the second part via a secondary stream filter of said separator to provide a filtered secondary stream and then discarding the filtered secondary stream via a secondary outlet, wherein the secondary outlet is downstream from the secondary stream filter, wherein the separator element comprises a cyclone separator and a baffle connected to the cyclone separator downstream from said cyclone separator, wherein a tube with a front-end inlet opening is provided as the baffle, said tube being positioned as an immersion tube in an area of an eye of a cyclone stream, and wherein the immersion tube passes through the cyclone stream.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an embodiment of an inventive separator in center longitudinal section.

(2) FIG. 2 shows the entire installation in which the inventive separator is constructed.

(3) FIG. 3 shows a view according to FIG. 1, in which the streaming directions are symbolized by corresponding arrows.

(4) FIG. 4 shows an alternative immersion-tube end piece 11 belonging to the separator with the separator in disassembled state.

DETAILED DESCRIPTION

(5) FIG. 1 shows the preferred embodiment of the separator 1.

(6) The separator 1 is realized here as an installation placed alongside the work machine, that is, a device that is situated, quasi freely or at least as independently as possible, beside the work machine that it is meant to serve—herein the figure of a mill M with a release of milled material MAG—and is connected by tubes with the machine; see also FIG. 2, illustrating this individual utilization.

(7) The separator 1 consists of a housing 2, which as a rule constitutes the separation from the outside. The housing 2, integrally with the major portion of its enclosing surface, forms a cyclone sheath tube, which is described more fully below.

(8) The processing gas inlet 9 is situated on the upper side of the housing 2. Processing gas, loaded with particles, is fed from the work machine, by way of the processing gas inlet 9, to the separator; said particles must be removed from it, at least essentially, in the next step.

(9) On its underside, the housing 2 is equipped with a product discharger 10 for expelling the particles extracted from the processing gas. A gas-proof element is provided on the product discharger 10. Preferably, the likely means used here include flap valves, flaps, rotary feeders or a firmly docked vessel. Ideally, the product discharger 10 is simultaneously configured as a modification opening, through which the plant installer can replace the immersion-tube end piece 11 (to be described immediately hereafter) of the immersion tube 3 for another such immersion-tube end piece. For this purpose the narrow diameter of the product discharger 10 is preferably of such dimensions that through it the immersion-tube end piece 11 can be released, removed and a new immersion-tube end piece 11 can be inserted, positioned and secured to the immersion tube 3.

(10) The immersion tube 3 can extend above the housing 2, on its upper side, as FIG. 1 shows.

(11) At least the greater part of the immersion tube 3, however, should preferably be situated inside the housing 2. The immersion tube is preferably arranged in such a way that its tube's longitudinal axis L runs vertically.

(12) As can be seen clearly from FIG. 1 or FIG. 3, the housing 2 and the immersion tube 3 are configured and constructed to interlock with one another in such a way that the ring-like space between the housing and the immersion tube directly behind the preferably tangential processing gas inlet forms a cyclone area, which can also be designated as the first separation zone 13. The configuration is selected in such a way that here a pre-cleaning takes place, with a degree of effectiveness, depending on product, grain size, density and temperature, of more than 90%.

(13) Joined thereto for streaming, the ring-like space widens between the housing 2 and the immersion tube 3. It thereby forms a slowdown zone 14 connecting to the cyclone area or the first separation zone 13. The slowdown zone is configured in such a way that it reduces speed to such an extent that the particles expelled to the outside in the cyclone area can fall directly downward into the product discharger.

(14) As can likewise be clearly recognized by reference to FIG. 1, the immersion tube 3 comprises—preferably on its lower front end—a front entry opening 20 open on the lower side, which functions as processing gas entry into the immersion tube.

(15) For the stream to go from the slowdown zone into the processing gas inlet and then to rise in the immersion tube, it must “bend” inward “sharply” into the interior of the immersion tube, as a rule by more than 150°, ideally by almost 180°.

(16) The slowdown zone has a synergistic effect to this extent, because the resulting speed reduction makes it possible for the processing gas flow to make a particularly sharp turn through the open front end of the immersion tube and into it.

(17) This “turning” occurs on path whose curvature radius is decisively smaller than the curvature radius of the paths in the cyclone. The “turning” overwhelms a good portion of the smaller particles still remaining until now in the stream. Due to inertia, they continue the motion previously forced upon them for a moment longer than the gas stream and therefore they too now fall into the product discharger 10.

(18) In the area where the stream curves into the interior of the immersion tube, a second separation zone 15 therefore takes shape, which differs in its separation principle or its deflection structure from that of the first separation zone 13, and therefore causes other-sized particles to be separated, namely those that have evaded the cyclone. It is true that in this second separation zone, in absolute quantitative terms, only far fewer particles are separated out than in the first separation zone; nevertheless, the second separation zone makes a decidedly positive contribution, because here considerably finer particles are excluded than before in the first separation area—that is, particles that otherwise would clog a particle filter with particular speed. With a corresponding configuration of the second separation zone, it is possible to exclude between 75% and 90% of those particles still borne by the processing gas after it leaves the first separation zone. This appreciably reduces the burdening of the mounted filter.

(19) As already mentioned, preferably the immersion tube, in the area where it forms the second separation zone, is configured in two or more parts and comprises a removable immersion-tube end piece 11. As a rule, the separator is made up of various immersion-tube end pieces, which form front entry openings with various slight diameters and/or comprise various lengths in the direction of the immersion tube longitudinal axis L and thereby influence separation behavior. It should be mentioned here that the precise location of the second separation zone and its distance from the first separation zone can be established, by means of the respective length of the immersion-tube end piece, in such a way that the second separation zone can have the most effective impact possible, depending on the concrete parameters.

(20) As can be seen from FIG. 1, the immersion tube 3 divides into a first branch 4 and a second branch 5. Thus it forms two separately streamed pathways. The first branch ends in the processing gas outlet 6. This processing gas outlet 6 here penetrates the housing 2 in the radial direction and ends preferably with a flange or tube connection outside the housing 2. Through this processing gas outlet 6, part or the major part of the processing gas, freed at least from most of its particle content, is conveyed back to the work machine or mill and recycled into it.

(21) The second branch 5 of the immersion tube 3 ends in the secondary outlet 7, which most often ends likewise in a flange.

(22) A filter 8, preferably positioned completely within the second branch 5, is mounted upstream of the secondary outlet 7 in flow sequence. The filter 8 constitutes a third separation zone 16, preferably situated above the second separation zone, and preferably, at least essentially, at the same height as the first separation zone.

(23) A smaller portion of the processing gas is diverted through the secondary outlet 7 and eventually is discarded. For this purpose, the secondary outlet 7 ends outside the immersion tube 3 with a flange or tube connection. A suction pump 22, which will be described in more detail hereinafter, can be flange-mounted at this point. It is connected to serve the separator 1 and therefore constitutes, in some cases, a functional component of it.

(24) At its upper end, the immersion tube 3 can end, or be equipped with a dust removal device 12 for the filter 8. In the simplest case, the dust removal device for the filter 8 is a simple, primarily electrically remote-actuated open-and-close valve. It controls a compressed-air connection. It enables the insufflation of compressed air against the direction of the filter. In more demanding cases, a valve is employed that enables a so-called knocking, that is, the impacting of the filter 8 with pressure surges in rapid succession. Alternatively, a mechanical knocking or vibrating apparatus, not illustrated, can also be provided here.

(25) The ring-like gap between the outer sheath surface of the filter 8 and the interior sheath surface of the immersion tube 3 should preferably be configured so that particles retained by the filter 8, at least agglomerated in clumps, can fall downward, preferably in a straight line as far as the product discharger 10—provided no accompanying withdrawal occurs through the first branch 4 and its processing gas outlet 6. It is essential that the particles already separated by the filter should be kept from being swept in and collected inside the aforementioned ring-like gap.

(26) To compensate for the internal pressure losses of the separator, an injector, a vacuum pump or a radial bellows (not illustrated) can be mounted on it downstream and then becomes a functional component of the separator.

(27) Thereafter, with reference again to FIG. 3, the gas and/or particle flow can be visualized.

(28) The arrow P1 symbolizes the entering processing gas with its particle content.

(29) The arrow P2 symbolizes the cyclone stream. On the other hand, the arrows P3 indicate how the stream in the slowdown zone is modified. As a result, the particles separated by cycloning now fall directly away, as indicated by arrows P4.

(30) The arrows P5 are relatively inconspicuous but important, showing how the stream is sharply diverted to the baffle, which is realized here by the immersion tube 3 or its immersion-tube end piece 11, so that an additional separation follows.

(31) The arrow P6 symbolizes the processing gas issuing out through the processing gas outlet and fed back into the mill. The arrows of the P7 type symbolize the secondary stream, which flows by way of the second branch in the direction of the filter 8. The arrows P8 symbolize the stream flowing away through the filter sheath into the filter interior, which is diverted and discarded as a secondary stream along the arrow P9.

(32) The arrows of type P10 symbolize the compressed air insufflated in some cases by the dust removal device in the opposite direction, serving for filter cleaning. The arrow P11 symbolizes how particles thereby blown off the filter fall into the product discharger 10.