Separator with a bypass

A separator may include a housing with a separation space in which a ventilation base is disposed and in which separation stock is perfusable by separation gas so as to separate fine stock from coarse stock. A separation-gas inlet and a separation-stock inlet may open into the separation space, and a fine-stock outlet and a coarse-stock outlet may lead out of the separation space. A bypass duct may be integrated in the housing for bypassing the separation space. The bypass duct may lead out of the separation-gas inlet and open out downstream of the separation space.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage Entry of International Patent Application Serial Number PCT/EP2015/000180, filed Jan. 30, 2015, which claims priority to German Patent Application No. DE 10 2014 101 188.0 filed Jan. 31, 2014, the entire contents of both of which are incorporated herein by reference.

FIELD

The present disclosure relates to static-operation separators for separating fine stock from coarse stock.

BACKGROUND

Static-operation separators separate bulk materials into two fractions having dissimilar distributions of particle sizes. Separating the fractions is performed in a separation space in which the separation stock, falling in from a separation-stock inlet in the direction of a coarse-stock outlet, is perfused in the transverse direction by a separation gas. Comparatively small particles are entrained by the separation-gas flow and transported to a fine-stock outlet, while comparatively large particles are discharged by way of the coarse-stock outlet.

The ventilation bases of a static separator are aligned so as to be more or less transverse to the movement direction of the separation stock, a step-type arrangement of the ventilation bases often being provided (DE 43 37 215 A1). According to one preferred embodiment, a ventilation base which is configured so as to be substantially planar is provided with a multiplicity of ventilation slots. The ventilation base here may be assembled from a multiplicity of individually replaceable slotted plates. The separation stock falling into the separation space impacts the ventilation base(s) and is perfused there by the separation gas. The dwelling time of the separation stock in the separation space may be increased by the separation stock impacting the ventilation base(s), on the one hand. On the other hand, the separation stock impacting on the ventilation bases causes separation-stock agglomerates, so-called slugs, which are often present to disagglomerate. Both lead to the separation effect of a static separator being enhanced.

Static separators are often combined with dynamic separators, the static separators, as coarse separator, typically being upstream of the dynamic separator which serves as a fine separator. Dynamic separators operate on the basis of separating two fractions of the separation stock which are dissimilar in terms of the distribution of the particle sizes by means of a rotatingly driven separation cage.

A combination of a static separator as a coarse separator, and of a dynamic separator as fine separator in a recirculating grinding mill for cement clinker is known from DE 43 37 215 A1, for example. The static separator therein is downstream of a roller press and is impinged by the latter with separation stock which is comparatively coarse and has a multiplicity of slugs. The coarse stock which has been separated in the static separator is fed back to the roller press, while the fine stock by means of the separation gas flow is infed to a tubular ball mill in which said fine stock is further comminuted. From the tubular ball mill, the separation stock is then infed to the dynamic separator in which a separation of the separation stock into medium-fine stock and finest stock is performed. The finest stock as finished stock is then eliminated from the separation gas in a sorter, while the medium-fine stock is fed back to the tubular ball mill. In the case of the recirculating grinding mill according to DE 43 37 215 A1, the static separator and the dynamic separator are kept apart in terms of both space and function by the interdisposed tubular ball mill. The static separator thus serves substantially for avoiding excessively large particles or slugs being infed to the tubular ball mill.

A device for separating bulk material, in which a static separator and a dynamic separator are disposed in direct succession and integrated in a common housing, thus being perfused by the same separation-gas flow, is known from DE 10 2011 055 762 A1. The upstream disposal of the static separator serves substantially for avoiding impingement of the rotatingly driven and comparatively delicate separation cage of the dynamic separator by large particles and slugs.

It is also disclosed in DE 10 2011 055 761 A1 that, in addition to a main separation-gas inlet for a static separator, additional openings which by means of flaps or slides may be embodied so as to be closable may be provided, on account of which regulation of the separation gas which is infed to the static separator is to be enabled.

Finally, a dynamic separator in the housing of which a bypass duct which bypasses the separation space is integrated is known from DE 42 56 970 C3, by way of which bypass duct part of the dust-air mixture which is infed by way of an inlet may be directed so as to avoid separation in the separation space. On account thereof, targeted influencing of the particle sizes in the finished stock leaving the dynamic separator is to be possible.

DETAILED DESCRIPTION

The present disclosure is based at least in part on the object of performing the separation effect of a static separator so as to be variable in as simple a manner as possible. In some examples, a separator may have a housing that configures a separation space in which one or a plurality of ventilation bases are disposed and in which separation stock is perfused by separation gas so as to separate fine stock from coarse stock. A separation-gas inlet and a separation-stock inlet may open into the separation space, and a fine-stock outlet and a coarse-stock outlet may lead out of the separation space.

The present disclosure is based at least in part on the concept that the volumetric flow of the separation gas being directed through the static separator represents an easy-to-influence control variable, the modification of which having a relevant effect on the separation effect of the separator. In particular, an adaptation of the distributions of the particle sizes of the material which is discharged from the static separator as fine stock, on the one hand, and as coarse stock, on the other hand, may be performed by modification of the volumetric flow of the separation gas. This may be performed, in particular, depending on the apparatuses (for example, a mill or a dynamic separator), which are downstream of the static separator. A modification of the drying effect of the (optionally heated) separation gas may also be achieved by adapting the volumetric flow.

By correspondingly actuating a blower which generates the separation-gas flow, the volumetric flow of the separation gas herein could in principle be set to the envisaged separation effect. However, it is disadvantageous here that the volumetric flow of the separation gas for an apparatus which is downstream of the static separator, in particular a dynamic separator, is also modified on account thereof.

In order for this potential disadvantage to be avoided it is provided according to the invention for the volumetric flow of the separation gas which is infed to the static separator, which preferably may be air, to be embodied in a variable manner in that at least one bypass duct, by way of which part of the separation-gas flow bypasses the separation space, is provided.

Accordingly, a static separator of the generic type, having at least one housing in which the separation space is located, in which one or a plurality of ventilation bases are disposed and in which separation stock is perfused by separation gas so as to separate the separation stock into fine stock and coarse stock, wherein (at least) one separation-gas inlet and (at least) one separation-stock outlet open into the separation space, and (at least) one fine-stock outlet and (at least) one coarse-stock outlet lead out of the separation space, according to the invention is characterized by at least one bypass duct, integrated in the housing, for bypassing the separation space, wherein the bypass duct leads out of the separation-gas inlet and opens out downstream of the separation space.

A separation space is understood to be in particular that region of the separator in which material separation, that is to say sorting out of a material of a specific grain size is performed. The material of a comparatively coarse grain size exits the separation space by way of the coarse-stock outlet, the material of comparatively fine grain size entering the fine-stock outlet. The fine-stock outlet is downstream of the separation space and is configured in such a manner that no material separation is performed therein.

The bypass duct opens into the separator downstream of the separation space, wherein the bypass duct into the fine-stock outlet, for example, or into a gas entry point of a second and in particular dynamic separator which is downstream of the first separator.

Herein, a bypass duct integrated in the housing is understood in particular to be at least one wall face (preferably all wall faces) which delimits (delimit) the bypass duct and which preferably runs (run) along the entire length of the bypass duct, is (are) part of the housing and, apart from functioning as a delimitation of the bypass duct, is (are) used in structural terms (as a supporting wall) or in functional terms (for example for directing a medium) for other parts of the separator.

By integrating the at least one bypass duct in the housing of the separator one or a plurality of advantages may be generated as compared with an externally routed bypass duct which may be configured in the form of a bypass hose, for example. In particular, a smaller space requirement, better accessibility of maintenance and inspection openings, simplified packaging and transportation of the separator, and/or less investment in assembling may be achieved. Compensators which may be required in the case of an externally routed bypass duct for equalizing dissimilar thermal expansions may also be dispensed with in the case of a bypass duct integrated in the housing.

In one preferred design embodiment of the separator according to the invention it may be provided that said separator has one static coarse separator and one fine separator, downstream of said coarse separator, integrated in one housing. Accordingly, it may be provided that a second, in particular dynamic, separator having a second separation space adjoins the fine-stock outlet, wherein a housing which configures the second separator and which surrounds the second separation space configures a medium-fine stock outlet and a finest-stock outlet, which may also be referred to as a ‘most-fine stock outlet.’ Herein, it may be provided in particular that the fine separator is a dynamic fine separator which accordingly comprises a rotatingly drivable separation rotor, for example in the form of a conventional separation cage, which is disposed in the second separation space. Such a separator which comprises a static coarse separator and a fine separator downstream thereof may be preferably utilized in combination with (at least) one blower for generating the separation-gas flow which is utilized by both (part-)separators.

The capability of influencing the volumetric flow of the separation gas which is directed through the static coarse separator by way of the bypass duct in the case of such a combination with a fine separator has advantages in particular since in this manner the volumetric flow through the static coarse separator may be implemented in a regulatable manner so as to be largely independent of the volumetric flow through the fine separator. It may be provided in particular that the total volumetric flow of the separation gas which is infed to the separator by way of the separation-gas inlet is planned with a view to the volumetric flow requirement of the fine separator, and the typically lesser volumetric flow requirement of the coarse separator is adapted by redirecting a more or less large part of the total volumetric flow past the (first) separation space of the coarse separator.

In order for the capability of regulating the volumetric flow of the separation gas that is directed by way of the coarse separator to be kept as variable as possible, a regulator element by means of which the available flow cross section of the bypass duct may be (manually or automatically) modified may be provided. The regulator element may be embodied as a regulator flap or as a regulator slide, for example, which is adjustable by means of an actuator.

Furthermore preferably, it may be provided that the bypass duct configures a plurality of flow ducts (which are kept apart in spatial terms). On account thereof, a more uniform distribution of the flow of the separation gas which is directed by way of the bypass duct and, on account thereof, also a more uniform introduction into the main flow of the separation gas in the fine-stock outlet may be achieved.

In the case of such a design embodiment of the bypass duct it may then also be provided in order for the part-flows of the separation gas that are directed by way of the individual flow ducts to be homogenized that one regulator element is provided for each of a plurality and in particular for each of all of the flow ducts. It may also be provided here that the regulator elements are individually adjustable.

In a furthermore preferred design embodiment of the separator according to the invention it may be provided that the flow ducts terminate in the fine-stock outlet at a spacing from the port of the bypass duct. On account thereof, the part-flows which are directed by way of the flow ducts are re-unified even before entering the fine-stock outlet and thus even prior to being mixed with the main flow of the separation gas. This may have a positive effect with a view to as uniform as possible an introduction of the part-flows which are directed by way of the bypass duct into the main flow.

Unification of the part-flows of the separation gas which are directed by way of the flow ducts may be particularly advantageous when the separation-gas flow which is directed by way of the bypass duct is introduced into the fine-stock outlet by way of a port opening which is comparatively small in comparison to the cross-sectional dimensions of the fine-stock outlet in the region of the port of the bypass duct. Herein, it may be particularly preferably provided that the bypass duct opens into the fine-stock outlet in a decentralized manner, on account of which the again mixed total flow of the separation gas may be imparted a swirl by means of the separation-gas flow which enters from the bypass duct into the fine-stock outlet which may have a positive effect in particular on the separation effect of a dynamic fine separator which is downstream of the static coarse separator. Herein, it may preferably be provided that the rotation direction of the swirl of the separation-gas flow corresponds to the rotation direction of the separation rotor of the dynamic fine separator.

“Decentralized” herein is understood to mean that the (mean) flow direction of the separation-gas flow entering from the bypass duct into the fine-stock outlet (and in particular the longitudinal central axis of the port opening) does not intersect the longitudinal central axis of the cross-sectional faces of the fine-stock outlet in the region of the port of the bypass duct. It may be provided in particular that the separation-gas flow entering from the bypass duct into the fine-stock outlet is introduced as far as possible from the longitudinal central axis and thus as close as possible to a wall of the housing that delimits the fine-stock outlet.

In as far as the separator according to the invention has at least two bypass ducts which may preferably be disposed on opposite sides of the first separation space, it may be provided for an increased swirl effect of the separation-gas flows entering from the two bypass ducts into the fine-stock outlet that each of these two bypass ducts does not only open into the fine-stock outlet in a decentralized manner but also mutually diametrically in relation to a longitudinal central axis of the fine-stock outlet.

In one furthermore preferred design embodiment of the separator according to the invention at least one intermediate wall which is disposed in the fine-stock outlet so as to be aligned transversely to the ventilation base(s) may be provided. The intermediate wall may have the effect of reinforcing the housing, on the one hand. On the other hand, an increase of the loading capacity of the main flow as a result of an increase in the Froude number may be achieved by the at least one intermediate wall which subdivides the flow space which is configured by the fine-stock outlet for the main flow of the separation gas into a plurality of part-flow spaces. This may be relevant in particular in the case of the design embodiment of a separator according to the invention in which part of the total volumetric flow of the separation gas which is infed by way of the separation-gas inlet is to be directed past the (first) flow space as required by means of the bypass duct(s).

In order for the intermediate wall to as far as possible not impede the introduction of the separation-gas flow which is directed by way of the at least one bypass duct it may be preferably provided that the bypass duct opens into the fine-stock outlet downstream of the intermediate wall.

In order to avoid as far as possible that diverting part of the volumetric flow of the separation gas from the main flow has a negative effect on the perfusion of the ventilation base(s) it may furthermore preferably be provided that the bypass duct leads out of the separation-gas inlet at (as large as possible) a spacing from the ventilation base(s). In terms of construction this may be implemented simply in that a partition wall which extends the bypass duct into the separation-gas inlet is provided.

The separator illustrated inFIG. 1comprises a static coarse separator1and a dynamic fine separator2which is directly downstream thereof. The latter are both integrated in one (multi-part) housing3, representing one functional unit.

The fine stock11by way of the fine-stock outlet8is infed to the dynamic fine separator2. By way of interaction with a rotatingly driven separation rotor14, having guide blades15, which is disposed in a (second) separation space13, fine separation arises, wherein comparatively large particles of the fine stock11, that is to say the medium-fine stock, is discharged from the second separation space13by way of a medium-fine stock outlet16, while comparatively small particles, that is to say the finest stock, this in particular also potentially being a finished stock to be produced, flow away with the separation-gas flow by way of a finest-stock outlet17.

The static coarse separator1is provided with two bypass ducts18which are integrated in the (part-) housing3of the coarse separator1and which are provided for directing part-flows of the total flow of the separation gas which enters the separator by way of the separator-gas inlet5in a regulatable manner past the first separation space4, on account of which these part-flows do not participate in the coarse separation taking place in the first separation space4. The two bypass ducts18are disposed on two opposite sides of the first separation space4and of the fine-stock outlet8, having rectangular cross sections. Herein, external walls of the housing3encompass the bypass ducts18as well as the separation space4and the fine-stock outlet8, while keeping apart in spatial terms the bypass ducts18on the one hand, and the separation space4as well as the fine-stock outlet8, on the other hand, is implemented by way of two partition walls19.

The partition walls19here are embodied so as to be extended upstream of the first separation space4(cf.FIG. 4), thereby protruding into the separation-gas inlet5. On account thereof, separation of the part-flows of the separation gas which are directed by way of the bypass ducts18from the main flow which is directed by way of the first separation space4is implemented at a comparatively large spacing (upstream) from the ventilation base9. On account thereof, it can be avoided as far as possible that diverting the part-flows has a negative influence on the perfusion of the ventilation base9by means of the main flow.

The diverted part-flows within the bypass ducts18are directed in a plurality of flow ducts21which run in parallel and which in spatial terms are kept apart by means of sub-partition walls20. Herein, each flow duct21at the entry side is assigned in each case one regulator element in the form of a regulator flap22which is rotatable by approx. 90° about a shaft. The volumetric flow of the part-flows of the separation gas which is directed by way of the bypass ducts18is regulatable by the regulator flaps22between a minimal value which is present in the case of fully closed regulator flaps22and which is essentially zero, and a maximum value in the case of fully opened regulator flaps22.FIGS. 6 and 8show the regulator flaps22in the fully closed position, while a partially opened position of the regulator flaps22is shown inFIG. 4.

Adjustment of the regulator flaps22is performed in each case by means of one actuator23for each bypass duct, which in each case acts directly on the shaft of one of the regulator flaps22, rotation of this one regulator flap22being transmitted by way of push-pull rods24and levers25to the other regulator flaps22of the respective bypass duct18.

The partition walls19which keep the bypass ducts18apart from the first separation space4and the respective part of the fine-stock outlet8terminate so as to be approximately level with the sub-partition walls20which subdivide the bypass ducts18into the flow ducts21. Downstream thereof, the housing configures in each case on outlet space26as part of the bypass ducts18(cf.FIG. 5). The part-flows which are directed in the individual flow ducts21of the bypass ducts18are collected in these outlet spaces26, and then enter the fine-stock outlet8in each case by way of a port opening27which extends only across part of the respective side of the fine-stock outlet8. It is provided here that the two port openings27of the two bypass ducts18in relation to a longitudinal central axis28of the fine-stock outlet8each are disposed in a decentralized and in a mutually diametrical manner (cf.FIG. 9; inFIG. 5the respective apertures30for partially keeping the outlet spaces26apart in spatial terms from the fine-stock outlet8are not shown). On account thereof, the part-flows which enter from the bypass ducts18into the fine-stock outlet8cause a swirl of the then reunited total flow of the separation gas about the longitudinal central axis28of the fine-stock outlet8. Herein, the rotation direction of the swirl corresponds to the rotation direction of the separation rotor14of the dynamic fine separator2.

It can also be seen inFIG. 5that the fine-stock outlet8is subdivided into part-spaces by a plurality (presently three) intermediate walls29, wherein the intermediate walls29are aligned transversely and in particular perpendicularly to the ventilation base9. The intermediate walls29serve for reinforcing the housing3, on the one hand, and on the other hand for increasing by means of an increase in the Froude number the load capacity of the main flow of the separation gas which has been reduced as a result of an optional diversion of the part-streams which have been directed by way of the bypass ducts18. The intermediate walls29terminate downstream, approximately level with the partition walls19and with the sub-partition walls20, and thus upstream of the port openings27of the bypass ducts18. On account thereof, the former impede as little as possible the mixing of the part-flows which exit from the bypass ducts18with the main flow of the separation gas and the formation of a swirl performed thereby about the longitudinal central axis28of the fine-stock outlet8.

FIG. 10shows a separator according to a further exemplary embodiment. The separator has a static coarse separator32and a dynamic fine separator34downstream thereof. The static coarse separator32is illustrated in a front view and corresponds substantially to the static coarse separator1illustrated inFIG. 2, having a ventilation base42. As opposed to the static separator1illustrated inFIG. 2, the static coarse separator32shown inFIG. 10has a housing36which may be configured so as to be tubular or to have a rectangular cross section, for example, serving as a connection piece between the ventilation base42and the fine-stock outlet. Two bypass ducts40by way of the which part-flows of the total flow entering the static separator32are directed past the ventilation base42and the first separation space38in a regulatable manner are disposed around the separation space38and within the housing36. In the exemplary embodiment of the separator illustrated inFIG. 10, the housing36extends in an arcuate manner up to a dynamic separator34which adjoins the static separator36, so that the flow perfusing the static separator32is deflected by approx. 180°, flowing into the dynamic separator34. Keeping apart in spatial terms the separation space38, or the fine-stock outlet of the static separator34, respectively, and the bypass ducts40is implemented by partition walls46. The partition walls46extend along the housing36of the static separator32. That region of the static separator in which no further material separation is carried out adjoins the separation space38of the static separator. The partition walls46of the bypass ducts40inFIG. 10extend across the length of the separation space38and across the length of the housing36in which sorting of coarse stock is performed. The partition walls46terminate in the fine-stock outlet which adjoins the separation space38, and the bypass flow and the separated fine-stock flow are collected there and enter the dynamic separator34.

As opposed to the separator which above has been described with reference toFIGS. 1 to 9, the fine stock which leaves the static separator is supplied in a substantially horizontal manner to the dynamic separator34, at the level with the separation rotor44.

FIG. 11shows a separator according to a further exemplary embodiment. The separator illustrated inFIG. 11corresponds substantially to the separator illustrated inFIG. 10, differing in that the partition wall48inFIG. 11extends beyond the fine-stock outlet up to the inlet to the dynamic separator34. The bypass flow and the separated fine-stock flow in the exemplary embodiment shown inFIG. 11are collected downstream of the separation space38and downstream of the fine-stock outlet. The partition walls48terminate at the downstream end of the fine-stock outlet at the entry to the dynamic separator. It is likewise conceivable that the partition walls48extend somewhat into the gas entry of the dynamic separator34.