ES3016809T3 - Multiple separators which are pneumatically connected to one another - Google Patents

Abstract

The invention relates to a separator (100, 300, 400, 500) for separating granular material into at least a fines fraction and a coarse fraction, comprising a housing (G) in which a stepped cascade (108, 108') permeable by the separation gas (5) is installed at an angle (α) deviating from the horizontal, at least one inlet channel (103) leading to the housing (G) for separating the gas, and at least one outlet channel (105a, 105a', 105b, 105b') leading from the housing (G) for separating the gas laden with fines, where, opposite the stepped cascade (108, 108') and separated from it by a separation zone (SZ), separation sheets (107, 107') are arranged one above the other in the manner of a Venetian blind. and where an inlet opening (102, 102', 102'', 102''') is arranged above the separation zone (SZ) in the upper part of the housing (G) and a discharge opening (104, 104') for the coarse material is arranged below the separation zone (SZ) in the lower part of the housing (G). According to the invention, it is provided that at least two individual separators (100', 100'', 100''', 100'''), arranged opposite each other, are pneumatically connected to one another by means of a common pressure equalization chamber (DAK), through which the separation gas flows into the respective inlet channels (103', 103'') of the at least two individual separators (100', 100'', 100''', 100'''). As a result, pressure fluctuations between two individual separators can be avoided and overall height can be saved. (Automatic translation with Google Translate, no legal value)

Description

DESCRIPTION

Multiple classifiers that are pneumatically connected to each other

The invention relates to a classifier for classifying granular classifying material into at least a fine material fraction and a coarse material fraction, which classifier has a housing in which a classifying gas-permeable staircase cascade is installed at an angle deviating from the horizontal, at least one inlet channel into the housing for the classifying gas, and at least one outlet channel from the housing for the classifying gas laden with fine material, whereby the classification flows arranged one above the other, in a shutter-like manner, are arranged opposite the staircase cascade and separated by a classification zone, and whereby an inlet opening for the classification material is arranged above the classification zone, in the upper part of the housing, and a discharge opening for the coarse material is arranged below the classification zone, in the lower part of the housing.

To classify the fine material to be classified, the material to be classified is allowed to fall over a cascade of stair-shaped baffles in a closed chamber, through which classifying air flows transversely, and the fine components are expelled by the classifying air. The expelled fine material is discharged from the chamber with the classifying air through an outlet channel, and the fine material is separated from the classifying air flow in another device. The classifiers described here are commonly referred to as V-classifiers due to their external structure.

The efficiency of V-classifiers is determined by their geometry. The chutes should not be too flat, to ensure sufficient flow of the material to be classified, nor too steep to allow the classifying air enough time to expel the fine material. A V-classifier should not have an arbitrary width, as very wide V-classifiers, which are wider than the material cone formed with a corresponding throughput, could cause a distribution problem across the width of the classifier. Therefore, the ideal shape of a V-classifier has geometric limits.

To increase the throughput of a system for classifying the material to be classified, it is possible to arrange many individual classifiers side by side. These classifier batteries operate independently and in parallel. The total separation throughput of the classifier battery constructed in this way is equal to the sum of the separation throughputs of the individual classifiers. To supply classifying air to the individual classifiers, they must be connected to a classifying air supply, usually central. This gives rise to problems with pneumatic control, which also occur on a much smaller scale in air conditioning systems. The classifying air flow rate differs between individual classifiers because the distances of the different individual classifiers from the central compressor vary. An individual classifier located closer to the compressor reduces the pressure in the waste line, so that individual classifiers located further from the compressor operate with a lower classifying air pressure. This means that the separation throughput, as well as the grain composition of the fine material, of the different individual classifiers differ. Although it is also possible to regulate the classifying air supply to individual classifiers using air flow regulators, controlling several individual classifiers is no longer trivial, as control oscillations can occur in the line from the compressor to the individual classifiers. This can occur due to the generation of dynamic air pressure fluctuations in the classification air throughput. In addition to the actual control oscillation, which is caused by the synchronization element between the actuator and the control element, there is also an oscillation in the air pressure that is introduced into the control system and accumulates within the system itself, potentially influencing the grinding circuit.

European patent application EP 1090 685 A1 describes a compact circuit grinding system in which two cascades are located opposite each other within the same housing. These cascades are not dissociated and tend to have one cascade operating at a higher pressure drop than the second, resulting in the cascades operating with different separation performances and classification results. A classifier according to the preamble of claim 1 is known from this document.

Chinese utility model CN 202460996 U shows individual classifiers operating in parallel and with different interconnections. Regarding classifying air, classifiers connected in series and those operating in parallel are shown.

German patent specification DE 102015 013892 B3 describes a double classifier in which two successive cascades, each forming its own classification zone, are arranged in a common housing. The two cascades are connected in series with respect to the classifying air.

European patent application EP 1084769 A1 presents a classifier combination consisting of a cascade classifier and a wire basket classifier in a common housing. The two classifiers are connected in series with respect to the classifying air.

International patent application WO 2013/079416 A1 also presents a classifier combination consisting of a cascade classifier and a wire basket classifier in a common housing. The two classifiers are connected in series with respect to the classifying air.

US Patent 2,294,290 A shows a battery of classifiers connected in parallel, each supplied with classification air via a common supply line. In this battery of classifiers, the last classifier operates at a significantly lower pressure than the preceding classifiers in the classification air supply line.

The object of the invention is therefore to provide a scalable classifier that is not built high, so as to save lifting work, and that has no tendency to oscillate, so that it classifies a uniform fine material, of the material to be classified, with a consistent grain composition.

The objective of the invention is achieved in that at least two individual classifiers, located opposite each other, are pneumatically connected via a common pressure equalization chamber, through which the classifying gas flows into the respective inlet channels of the individual classifier. Further advantageous embodiments are specified in the claims subordinate to claim 1.

According to the inventive idea, a pressure equalization chamber is arranged between the more than one individual classifier, via which the more than one individual classifier are connected to one another. The pressure equalization chamber makes individual classification air flow regulation unnecessary, since it supplies each individual classifier with the same classification air pressure. The common, central pressure equalization chamber is connected to each individual classifier in a geometrically identical manner, so that air pressure fluctuations cannot arise due to different air paths between the individual classifiers. This design makes it possible to replace a large classifier with a multiple arrangement of smaller, interconnected classifiers according to the invention.

In a preferred embodiment of the classifier according to the invention, the classifying gas resistance, which describes the pressure drop of the classifying gas from the inlet channel to the outlet channel for a given classifying gas flow rate, is provided to be approximately the same in at least two individual classifiers. The classifying gas resistance is determined by the flow cross-section of the individual classifier in question, the path length that the classifying air must travel in the individual classifier, and the air flow rate. The air flow rate describes whether the classifying air is redirected several times or flows in an ideal cylindrical tube. The effects of the geometric shape of a device on its flow resistance are well known to those skilled in the art, although predictability is not trivial. Thanks to the comparability of the classifying air resistance between the individual classifiers, the tendency toward control fluctuations and the tendency toward air pressure fluctuations in the supply line with classifying air are reduced, and the classification efficiency is equalized.

In a preferred embodiment of the invention, the more than one individual classifier is constructed mirror-inverted relative to one another, such that it faces each other and exhibits the same reaction to the classification air flow. It is advantageous in this case for the more than one individual classifier to always be constructed in pairs that are mirror images of one another. It is irrelevant whether the individual classifiers exhibit mirror symmetry or not, i.e., whether they do not exhibit any mirror planes. The pressure compensation chamber of the classifier according to the invention can be constructed in various ways. It has proven advantageous for the pressure compensation chamber to be directly connected to the classification air inlet openings of the more than one individual classifier. In this case, it may happen that the material to be classified also reaches the pressure compensation chamber. This occurs due to unwanted interruptions in operation, deviations from ideal behavior, or short-term overloading of an individual classifier. In order to be able to discharge the material to be sorted from the pressure compensation chamber, in a preferred embodiment of the classifier, it is provided that the pressure compensation chamber has its own material discharge opening.

In another embodiment of the classifier according to the invention, it can be provided that the at least two individual classifiers have, in addition to a discharge opening for fine material, a further discharge opening for a medium material fraction. By discharging the medium material fraction, the composition of the fine material can be controlled very precisely.

To ensure that the pressure equalization chamber between the more than one individual classifier distributes the pressure evenly to the individual classifiers, the pressure equalization chamber is connected to the inlet ducts of the at least two individual classifiers via a perforated panel wall or a grille wall. The perforated panel wall or grille provides a low resistance to the classification air flow. During equalization, the air flow resistance of an individual classifier acts as a passive control element with a small but perceptible compensation function for the classification air flow, so that the pressure in the pressure equalization chamber in the more than one individual classifier results in a classification air flow rate that is as identical as possible between the individual classifiers.

To ensure a uniform flow to more than one individual classifier, in a preferred embodiment of the classifier, the classifying gas flowing through the pressure equalization chamber to the inlet channels of the at least two individual classifiers can be provided so that it flows into the pressure equalization chamber exactly centrally between the at least two individual classifiers. The geometric center results in a lower tendency toward air pressure fluctuations, which have different effects for different individual classifiers.

In a first specific embodiment of the invention, it is provided that pairs of opposing classifiers are constructed as a classifier battery, arranged in pairs one behind the other and interconnected with the same pressure equalization chamber. In order to subject the separated fine material to further division, the housing outlet channel of the individual classifier for fine material can be connected to a separate rod basket classifier assigned to this individual classifier, or the housing outlet channels of more than one individual classifier for fine material can be connected to a common rod basket classifier.

The invention is explained in more detail with reference to the following figures. It is shown in:

Fig. 1 a truncated view of a prior art V-classifier,

Fig. 2 a sectional view of a classifier according to the invention,

Fig. 3 the classifier of Fig. 2 with additional rod basket classifiers,

Fig. 4 an embodiment of the classifier according to the invention, with a battery arrangement,

Fig. 5 a top view of the classifier according to Fig. 2, with the cut line drawn,

Fig. 6 a top view of a classifier according to the invention in a cross arrangement,

Fig. 7 a top view of a classifier according to the invention in star arrangement.

A V-classifier 1 is shown in vertical section in Fig. 1 for classifying granular classifying material into at least a fine material fraction and a coarse material fraction according to the prior art. This known V-classifier has a housing G, in which a gas-permeable classifying staircase cascade 8 is installed at an angle α deviating from the horizontal. In the drawing, to the right of the staircase cascade 8 is an inlet channel 3 through which the classifying gas can flow into the housing G. The granular classifying material to be classified falls through a classifying material inlet opening 2 for classifying material located above the classification zone SZ in the upper part of the housing G onto the staircase cascade, where it slides over the cascades and is flowed through by the classifying gas flowing in from the right. The classifying gas flowing into the V-classifier 1, i.e. air or hot drive gas, exits the housing G through at least one outlet channel 5a, 5b, whereby the classifying gas is loaded with fine material, which in turn is suspended in the classifying gas. The classifying flows 7, arranged one above the other in a louver-like manner and located opposite the staircase cascade 8 and separated by a classification zone SZ, direct the classification flow in a vertical direction, in which the classifying material is separated into different particle size fractions by gravity and the ascending classifying gas. The fine material suspended in the classifying gas exits the V-classifier 1 through the outlet channels 5a and 5b. However, the coarse material falling downwards into the classifying gas in the classifying zone falls below the classifying zone SZ in the lower part of the housing G, through a classifying material discharge opening 4 to the outside for the coarse material, below the V-classifier. In order to dimension the performance of the classifiers, the prior art provides for operating several classifiers and supplying the inlet channels 3 of the different V-classifiers with classifying gas via a Y-line 6 as a supply line, generally via a line with branches. This can lead to problems in maintaining an optimal operating condition for each individual V-classifier if the classifying gas pressure in the individual V-classifiers in the supply line is already slightly different.

2 shows a sectional drawing through a classifier 100 according to the invention along the section line shown in FIG. 5. In accordance with the present invention, it is provided that at least two individual classifiers 100', 100'' arranged opposite each other are pneumatically connected to one another via a common pressure equalization chamber DAK, through which the classifying gas flows into the respective inlet channels 103', 103'' of the at least two individual classifiers 100', 100''. In the exemplary variant shown here, two individual classifiers 100' and 100'', both of which are part of the classifier 100, are connected to one another via the pressure equalization chamber DAK, with the entire opening of the grid wall 109, 109' present in the inlet channels being freely wide towards the pressure equalization chamber. In this way, the free cross-section of the inlet channels 103, 103' is not reduced by a pipe cross-section of a supply line. This has the advantage that pressure fluctuations cannot occur and the individual classifiers 100' and 100" can therefore operate in a synchronized operating state. The pressure equalization chamber between the at least two individual classifiers is delimited by a roof D, a floor B, and a rear surface R (Fig. 4), as well as by a front wall not shown here by the section line. An inlet channel 103 leads to the pressure equalization chamber and is arranged as centrally as possible between the individual classifiers 100' and 100". The individual classifiers 100' and 100" are constructed similarly to prior art V-classifiers. They classify the coarse material into a fine material fraction and a coarse material fraction. Both individual classifiers 100', 100" have a continuous housing G, in which a stair cascade 108, 108' permeable to classifying gas is installed at an angle a that deviates from the horizontal. In the drawing, between the two stair cascades 108 and 108' there is an inlet channel 103 through which the classifying gas can flow into the pressure equalization chamber DAK. The granulated classifying material to be classified falls through a classifying material inlet opening 102, 102'' for the classifying material, located above the respective classification zone SZ, SZ' of each individual classifier 100', 102'', in the upper part of the housing G, onto the respective stair cascade 108, 108', where it slides over the cascades and is passed through by the incoming centrally flowing classifying gas. The classifying gas flowing into the individual classifier respective, i.e. hot drive air or gas, leaves the housing G through at least one outlet channel 105a, 105a', 105b and 105b', whereby the classifying gas is loaded with fine material which is in turn suspended in the classifying gas. The classifying flows 107, 107', arranged one above the other in a shutter-like manner, and located opposite the respective staircase cascade 108, 108' and separated by a classification zone SZ, SZ', direct the classification flow in a vertical direction, in which the classifying material is separated into different grain size fractions, thanks to gravity and the ascending classification gas. The fine material suspended in the classifying gas leaves the respective individual classifier 100', 100'' through the outlet channels 105a, 105a' and 105b, 105b'. In contrast, Coarse material falling downwards in the classification zone into the classification gas falls into a classification material discharge opening 104, 104' for the coarse material to the outside below the classification zone SZ, SZ' in the lower part of the housing G, below the respective individual classifier 100', 100''.

An enlargement of the classifier 100 is shown in Fig. 3, in which a rod basket classifier 200, 200' is placed in each of the outlet channels 105a, 105a' to further separate the fine material suspended in the classifying gas. The size relationships between the individual classifiers 100', 100'' and the rod basket classifiers 200, 200' shown here are not to scale. Essentially, the interconnection is shown here. It is possible for each outlet channel 105a, 105a' to have its own rod basket classifier assigned to it. Alternatively, it is also possible for the outlet channels 105a and 105a' to be connected and direct the classifying gas with the fine material suspended therein to a common rod basket classifier.

A particular embodiment of the classifier according to the invention is shown in Fig. 4 as classifier 300. In this case, three pairs of rows of individual classifiers are arranged in a battery-like arrangement, such that a central pressure equalization chamber DAK supplies classifying gas to the six individual classifiers. The pressure equalization chamber DAK is delimited by a floor B, a roof D, a rear wall R and a front wall not shown here. The coarse material falling from the individual classifiers is transported via conveyor belts 150 and 150 to return to a classifying or grinding circuit.

In Fig. 5, the classifier of Fig. 2 is shown in a top view. In this embodiment of the invention, the pressure equalization chamber DAK is designed to have a comparatively large volume compared to the volume of the individual classifiers, thereby avoiding pressure fluctuations between the two individual classifiers. Thanks to the large-volume pressure equalization chamber DAK, it is also possible to pneumatically couple more than two individual classifiers of 100', 100" to one another via a common pressure equalization chamber DAK. In Fig. 6, two pairs of individual classifiers 100', 100", 100''', 100"" are pneumatically coupled to one another via a cross arrangement via a common pressure equalization chamber to form a classifier 400. This variant can be further improved so that, as shown in Fig. 7, even 8 individual classifiers are coupled to one another in a star-shaped arrangement to form a classifier 500.

LIST OF REFERENCE SYMBOLS

Claims (9)

CLAIMS 1. A classifier (100, 300, 400, 500) for classifying granular material to be classified into at least a fine material fraction and a coarse material fraction, comprising: - a housing (G) in which a stair cascade (108, 108') permeable to the classifying gas is installed at an angle (a) deviating from the horizontal; - at least one inlet channel (103) to the housing (G) for the classifying gas; and - at least one outlet channel (105a, 105a', 105b, 105b') from the housing (G) for the classifying gas laden with fine material; whereby the sorting flows (107, 107') which are arranged one above the other, like a blind, are arranged in front of the staircase cascade (108, 108') and separated by a sorting zone (SZ); and whereby a classifying material inlet opening (102, 102', 102", 102m) is arranged above the classification zone (SZ) in the upper part of the housing (G); and a material discharge opening (104, 104') for coarse material is arranged below the classification zone (SZ) in the lower part of the housing (G). whereby at least two individual classifiers (100', 100", 100'', 100""), located opposite each other, are pneumatically connected via a common pressure equalization chamber (DAK), through which the classifying gas flows into the respective inlet channels (103', 103") of the at least two individual classifiers (100', 100", 100''', 100""), characterized in that the pressure equalization chamber (DAK) is delimited by a ceiling (D), a floor (B), and a rear surface (R), as well as by a front wall, and whereby the pressure equalization chamber (DAK) is connected to the inlet channels (103) of the at least two individual classifiers (100', 100", 100m, 100") by means of a perforated panel wall or a grid wall (109, 109'). 2. The classifier according to claim 1, characterized in that the classification gas resistance of the at least two individual classifiers (100', 100", 100m, 100""), defining the pressure drop of the classification gas from the inlet channel (103, 103') to the outlet channel (105a, 105a', 105a", 105a"', 105b, 105b', 105b", 105bm) at a predetermined classification gas flow rate in an individual classifier (100', 100", 100'", 100""), are approximately identical. 3. The classifier according to claim 1, characterized in that the at least two individual classifiers (100', 100", 100m, 100") are constructed so that they are mirror-inverted relative to each other and, with the exception of the mirror-inverted construction, are of identical construction. 4. The classifier according to one of claims 1 to 3, characterized in that the pressure compensation chamber (DAK) has its own sorting material discharge opening (104"). 5. The classifier according to one of claims 1 to 4, characterized in that the at least two individual classifiers (100', 100", 100m, 100""), in addition to an outlet channel (105a, 105a') for the classifying gas containing fine material, have a further outlet channel (105b, 105b') for a medium material fraction. 6. The classifier according to one of claims 1 to 5, characterized in that the classifying gas, which flows through the pressure equalization chamber (DAK) into the inlet channels (103, 103') of the at least two individual classifiers (100', 100", 100'", 100'''), flows into the pressure equalization chamber (DAK) exactly centrally between the at least two individual classifiers (100', 100", 100''', 100'''). 7. The classifier according to one of claims 1 to 6, characterized in that the pairs of individual classifiers (100', 100", 100m, 100''') arranged opposite each other are constructed as a classifier battery, arranged in pairs one behind the other, and are interconnected with the same pressure equalization chamber (DAK). 8. The classifier according to one of claims 1 to 6, characterized in that the pairs of classifiers opposite each other are arranged in a circle, whereby the individual pairs of classifiers (100', 100", 100m, 100''') are arranged in a cross- or star-shaped geometry. 9. The classifier according to one of claims 1 to 8, characterized in that the outlet channels (105a, 105a') of the at least two individual classifiers (100', 100", 100m, 100''') for the classifying gas laden with fine material are respectively connected to a rod basket classifier (200) or to a common rod basket classifier. �