EP1153661B1 - Mill separator - Google Patents

Abstract

The mill classifier has a dynamic sifter part with a ring (4) of guide flaps (5) whose flow channels are divided horizontally and have partial channels (23) for smoothing out the inflow of the rotor strips (7). The channels are divided by horizontal guide devices formed as guide plates (8) fixed on the flaps (5). The plates can be welded uniformly spaced one above the other

Description

The invention relates to a mill classifier, in particular a roller mill classifier, according to the preamble of the claim 1.

DE 36 17 746 A1 discloses a roller mill with an attached Classifier known which a fixed Leitklappenkranz and a concentrically arranged, rotating Has lamellae basket. Between the classifier housing and the Leitklappenkranz is a cylindrical Annular space formed, which leads to an increase in speed of the laden with the grain to be examined fluid should lead. The fixed baffles of the Leitklappenkranzes are to the tangential flow of the rotating Lamellare in the direction of rotation and the slats of the Display basket set in the opposite direction, whereby the visual result should be improved. By the front of the Leitklappenkranz trained annular space, which is down to in extended the mill into it by means of a double mantle can be, and the speed increase achievable with it of the fluid should be the flow of the Leitklappenkranzes uniform over the entire height and one premature precipitation of coarse grits can be prevented.

EP 0 204 412 B1 discloses a mill classifier, whose rotating lamellar viewing basket is adjustable Leitschaufelsystem is concentrically surrounded. The vane system consists of two or more nozzle sets, which are arranged one above the other on stationary rings and are independently adjustable.

The lamellae used in the aforementioned mill classifiers or inguinal rotor usually has a number of strips which is at least twice as high as the standard classifiers, which has a cone-shaped inguinal rotor screwed on a double cone rotor, slanted Have visible strips.

To reduce the associated, relatively high production costs already became a selective sifter proposed (European Patent Application 123 98 66, prior art under Article 54 (3) EPC), softer the advantages of a ledge rotor with respect to the suspension and storage and in particular in terms of number the rotor strips takes over and with the help of a Leitklappenkranzes allows a purely dynamic sighting. The guide damper has adjustable and flow-optimized Leaflets, which one rising from the mill Regrind fluid flow to a tangential to radial Flow of rotor blades, which are vertical and not are arranged more obliquely and a radial dimensioning have, forces.

This is a selective screening without an upstream static sighting through flow-optimized baffles achieved, which has a rounded leading edge and at least have a baffle and opposite the rotor bars of the inguinal rotor can be made in such a way that a parallel flow without constriction in the Outflow or an expanding outflow with diffuser effect established. The proposed selective separator Advantageously, not only rotor bars as in Lesche-Kreisel- / basket-classifier LKS, but also its classifier housing and classifier top, drive and drive shaft on. The space for the rising regrind fluid flow thus narrows over the height of the Leitklappenkranzes, causing the particle flow in the flow channels of the Leitklappenkranzes in is accelerated.

It is known that in a Wälzmühlenseer, which integrated into the roller mill or on the mill housing sitting, the regrind particles of the two-phase mixture due their inertia tends to almost reach the soffit to stream. From there, the particles are due to the from the mill fan generated drag force of the fluid Rotated axis of the classifier. Wear marks on the baffles prove that the particle concentration in the upper area of the baffles is particularly high and a uniform radial velocity over the height of the rotor strips can not be achieved.

The invention has for its object to provide a mill classifier for an ascending Mahlgut fluid mixture, in particular a Wälzmühlenseer, which ensures a high selectivity and a homogenization of the flow of the rotor blades on their height at a comparatively low production costs.

According to the invention the object is achieved by the features of the claim 1 solved. Advantageous and advantageous embodiments are in the description of the figures and in the subclaims contain.

The invention is based on the idea, one possible uniform radial velocity over the height of the Rotor strips by a horizontal subdivision of the flow channels to reach the static diffuser. tries have shown that an arrangement of horizontal intermediate rings on inguinal rotor to no change in the admission the upper portions of the rotor strips leads. A made according to the invention horizontal division in the region of the Leitklappenkranzes, such that each of two baffles formed flow channels in sub-channels surprisingly not only leads to a homogenization of the radial component of the fluid about the height of the rotor bars, but also to a homogenization the particle flow over the height of the rotor bars and to an improved selectivity of the sighting.

It was found that by a horizontal subdivision the flow channels of the Leitklappenkranzes in several, superimposed sub-channels a significantly reduced Particle concentration in each area of the rotor bars can be achieved while in the conventional flow channels without horizontal dividing or guiding devices an increased loading of the upper rotor bar areas to be recorded.

The through the subdivision of the flow channels of the Leitklappenkranzes achieved reduction of the vertical component at equalization of the radial component of the particle flow and the associated homogenization of the particle flow about the height of the rotor bars can with a better and faster draining one in the visual space between the rotor strips and the Leitklappenkranz formed Grießewolke be explained. For a concentrated particle supply in the upper region of the Leitklappenkranzes also the inguinal rotor in a comparable area its upper end acted upon. In the visual space between the inguinal rotor and the Leitklappenkranz enters a relative high concentration of oversized grain rejected by the rotor in Shape of a semolina cloud. This semolina cloud passes under Gravity effect the viewing area or viewing gap of top down over its entire height before entering the flow-calmed semolina cone below the baffles falls. While passing the Sichtspaltes is the Grießewolke but constantly from the fluid, which from the grinding chamber upwards and through the flow channels of the Leitklappenkranzes flows, blown again. With flow channels of the Leitklappenkranzes without a horizontal subdivision this blowing happens with a distinct vertical Flow component in the flow channels of the guide flaps, which are directed upwards and only slightly inwards is. However, this vertical flow component hinders significantly the free fall of the concentrated semolina cloud. With the aid of the horizontal guide devices according to the invention in the flow channels of the Leitklappenkranzes the vertical flow component is reduced or switched off and the radial flow component relative to Overall speed increased, so that blowing the Grießewolke upwards no longer occurs or to a minimum is reduced and an unhindered outflow of the now rectified semolina cloud can be down.

Due to the unobstructed outflow of the inguinal rotor rejected coarse particles is by the inventive horizontal subdivision of the flow channels of the baffles achieved an improvement in the selectivity of the classifier. The fanned over the subchannels formed Supply of the particle flow from the baffle system to the Rotor bars leads to a reduction of the specific Rotor load, as it currently exists in the upper rotor area. While in the prior art a concentrated stress of an upper region of the Visual strips occurs are in the inventive Mühlensicht the rotor blades over their entire height with applied to an approximately equal mass flow of particles, causing it to lower the maximum specific inguinal loading of the inguinal rotor comes.

It is advantageous to have a horizontal subdivision of the Flow channels by means of guide devices, in particular horizontal baffles, which are spaced above each other can be arranged to perform.

Conveniently, the horizontal baffles to the Flaps attached, welded, for example. To one Counteract wear of the horizontal baffles, It is recommended that the baffles at least on their Wear side to form wear-resistant and, for. with a wear-resistant material, armor or coating to provide.

In a particularly simple and inexpensive training the horizontal baffles are evenly spaced attached to each other on the baffles.

Basically, it is convenient to the distances between the To choose baffles so that the flow resistance of the Grist-fluid mixture over the entire, horizontally divided Height of the flow channels of the Leitklappenkranzes remains approximately constant.

Depending on the grist to be seen and the required Fines may be beneficial to the horizontal Baffles with one up or down to arrange decreasing distance.

For deflectors, which are fixed and not pivotable to a Leaflet can be arranged, the horizontal Baffles each at two adjacent vanes of a Flow channel fixed, in particular welded become.

In Leitklappenkränzen with adjustable arranged vanes it is advantageous to the horizontal baffles to be attached to the baffles in a flying manner. When the baffles in each case only on one side of the guide flaps horizontally be arranged, it is for a changeable angular adjustment of the baffles useful, the baffles form such that an adjustment distance to the adjacent Guide flap is present.

In another training variant, the horizontal Baffles mounted on both sides of a deflector, flying where both baffles are the same or different Width may have.

For an effective subdivision of the flow channels of the Leitklappenkranzes it is appropriate to the horizontal To form baffles of two adjacent baffles in such a way that they are with their free edge areas overlap. The attachment of the overlapping baffles should be done at the adjacent vanes so that they are in the overlap area only with a small Distance, but against each other adjustable superimposed.

For mill classifiers with flow-optimized baffles, which, for example, according to the European patent application 123 99 66 (state of the art according to Article 54 (3) EPC), it is appropriate to use the horizontal ones Baffles on the vertical baffles of the baffles to fix.

In another training variant, the horizontal Subdivision of the flow channels of the Leitklappenkranzes with Help made by horizontal guide rings or ring segments become. The horizontal guide rings or ring segments can then at the leading edges, for example, flow pipes, the flow-optimized vanes are attached. An adjustment of the baffles is by horizontal Recesses which are complementary to the guide rings or Ring segments, for example, slit-like design can, guaranteed.

Experiments have shown that a separating sharpener in accordance with European Patent Application 123 99 66 (Article 54 (3) EPC) by the invention subdivided flow channels of the Leitklappenkranzes can be further optimized. Through flow simulations could be proved by horizontal Baffles in Leitklappenkranz a significantly stronger radial component the streamlines is achieved and not only a gas flow, but also a particle flow a stronger deflection experiences and the supply of particles is equalized over the height of the sifter rotor.

Fig. 1

einen erfindungsgemäßen Mühlensichter;

Fig. 2

einen ausschnittsweisen Horizontalschnitt des erfindungsgemäßen Mühlensichters gem. Fig. 1

Fig. 3

eine ausschnittsweise Ansicht eines von zwei fest angeordneten Leitklappen gebildeten Strömungskanals mit horizontalen Leitblechen und

Fig. 4

eine ausschnittsweise Ansicht eines von verstellbaren Leitklappen gebildeten Strömungskanals mit horizontalen Leitblechen.

The invention will be further explained below with reference to a drawing; in this show in a highly schematic representation

Fig. 1

a mill classifier according to the invention;

Fig. 2

a fragmentary horizontal section of the mill classifier gem. Fig. 1

Fig. 3

a fragmentary view of a flow channel formed by two fixed vanes with horizontal baffles and

Fig. 4

a partial view of a flow channel formed by adjustable vanes with horizontal baffles.

Fig. 1 shows a rolling mill classifier 2, which in a Roller mill (not shown) integrated or on this can be put on. The roller mill classifier 2 is a selective sifter, which is a rod sifter with an upstream baffle system is. The rolling mill classifier 2 essentially has one Housing 30, an upper housing part 31 with outlet nozzle for Fine material 34, a strip rotor 6 with vertically arranged Rotor strips 7 and a concentric with the strip rotor. 6 arranged Leitklappenkranz 4, between which a Classifying space 17 is formed.

A in a swirl flow from a nozzle ring of the roller mill (not shown) upwardly flowing regrind-fluid mixture 3 enters the mill classifier 2, which is located in Area of the Leitklappenkranzes 4 tapers upwards. The Rotor bars 7 of the cylindrical guide rotor 6 are almost the same height as the guide flaps 5 of the Leitklappenkranzes 4 on.

The guide flaps 5 of the Leitklappenkranzes 4 are optimized flow trained and can be up for a tangential radial outflow are adjusted about a vertical axis 9 (see also Fig. 2). To reach over the entire height uniform flow of the rotor strips 7 and a to achieve an improved separation effect of the mill classifier 2, are in the area of the Leitklappenkranzes 4 horizontal guide devices 8 arranged. As horizontal guidance devices are baffles 8 in a substantially horizontal orientation attached to the baffles 5. In the present Embodiment are each five horizontal baffles 8 formed in each of two vanes 5 Flow channels 13 arranged and form six sub-channels 23 for a fanned flow of the rotor strips. 7

The flow channels 13 and sub-channels 23 go from the figures 2 to 4, in which training variants of the horizontal Guides or baffles 8 and their arrangement represented in the region of the Leitklappenkranzes 4 are.

Fig. 2 shows a plan view of a section of a horizontal section through the mill classifier 2. On a base plate 18 are adjustable, flow-optimized baffles 5 arranged and surrounded to a Leitklappenkranz 4 a strip rotor 6 concentric. The rotor strips 5 of the inguinal rotor 6 can as Z-bars according to the lower Part of Fig. 2 or as radially oriented flat bars formed of lesser radial extent than the Z-strips be (see upper part in Fig. 2).

The guide flaps 5 each have a flow pipe as a rounded Leading edge 10 and a vertical baffle 11 on which tangentially to the leading edge 10 with the help fasteners 16, e.g. mounting flanges, is attached. The guide flaps 5 are around a vertical Axis 9 adjustable and form flow channels 13 with a Diffuser effect. It is based on the already cited German Patent Application 199 61 837.2 referenced which component of the present application.

The for horizontal subdivision of the flow channels 13th arranged horizontal baffles 8 are for the better Overview in Fig. 2 in each case only in each second flow channel 13 drawn.

An approximately in the middle of Fig. 2 illustrated flow channel 13, in a first variant, has a horizontal Guide plate 8, which on the vertical guide plates 11th the adjacent guide flaps 5 is welded. Such Arrangement of the horizontal baffles 8 requires a fixed arrangement of the guide flaps, which thus not adjusted can be (see also Fig. 3).

In flow channels 13, which in the section of FIG. 2 are shown above and below, horizontal baffles 8 each formed on both sides of the guide flaps 5 and overlap in an overlap area 14. In this Training variant, the baffles 5 for a required adjusted tangential to radial outflow become.

Fig. 3 shows a partial view of the middle flow channel 13 to arrow A of Fig. 2, but with fixed Leader 5. The leaflets 5 are on a base plate Welded 18 and have stacked, horizontal baffles 8, which the flow channel Divide 13 into several sub-channels 23. The lower upstream sides 15 of the horizontal baffles 8 are resistant to wear educated.

4 shows a partial view according to arrow B in FIG. 2 again and shows a flow channel 13, which of pivotable, flow-optimized baffles 5 formed is. To ensure the adjustment of the baffles 5, are the horizontal baffles 8 on both sides of Leitklappen 5 and not shown here vertical Guiding plates 11 attached and with an adjustment 12th formed to the respective adjacent guide flap 5. To one to achieve efficient subdivision of the flow channel 13, overlap the horizontal baffles 8 with free edge regions in an overlap region 14. The horizontal baffles 8 are so on the baffles 5 or their vertical baffles 11 attached, In particular, they welded with a small Distance over each other.

Claims (14)

1. Mill classifier for a rising ground material-fluid mixture, particularly roller mill classifier, having a dynamic classifier part, which is constructed as a bladed rotor (6) and has rotor blades (7), and having a guide vane ring (4) as static guide means, which has guide vanes (5) and flow channels (13) constructed between the latter and which concentrically surrounds the bladed rotor (6) accompanied by the formation of an annular separating area (17),
   characterized in that
   the flow channels (13) of the guide vane ring (4) are horizontally subdivided and have partial channels (23) for rendering uniform the incident flow over the height of the rotor blades (7).
2. Mill classifier according to claim 1,
   characterized in that
   horizontal guide means (8) are provided for subdividing the flow channels (13) of the guide vane ring (4).
3. Mill classifier according to claim 2,
   characterized in that
   the horizontal guide means are constructed as horizontal guide plates (8) and are fixed to the guide vanes (5).
4. Mill classifier according to claim 3,
   characterized in that
   the horizontal guide plates (8) are welded to the guide vanes (5).
5. Mill classifier according to claim 3 or 4,
   characterized in that
   the horizontal guide plates (8) are superimposed with a uniform spacing.
6. Mill classifier according to claim 3 or 4,
   characterized in that
   the horizontal guide plates (8) are arranged with an upwardly increasing or decreasing spacing.
7. Mill classifier according to one of the claims 3 to 6,
   characterized in that
   in each case the horizontal guide plates (8) are fixed to two guide vanes (5) of one flow channel (13), whereby the two guide vanes (5) are non-adjustable.
8. Mill classifier according to one of the claims 3 to 6,
   characterized in that
   the guide vanes (5) are adjustable about a vertical axis (9) and the horizontal guide plates (8) are fixed with an edge region to one side of the guide vanes (5).
9. Mill classifier according to claim 8,
   characterized in that
   the guide vanes (5) are constructed in flow-optimized manner for a tangential to radial incident flow on the vertically oriented rotor blades (7) of a cylindrical bladed rotor (6) and have at least one vertical guide plate (11) and that the horizontal guide plates (8) are at least fixed to the vertical guide plates (11) of the guide vanes (5).
10. Mill classifier according to claim 8 or 9,
    characterized in that
    the horizontal guide plates (8) are constructed with an adjustment spacing (12) with respect to the adjacent guide vane (5).
11. Mill classifier according to one of the claims 7 to 10,
    characterized in that
    the horizontal guide plates (8) are fixed to both sides of a guide vane (5).
12. Mill classifier according to claim 11,
    characterized in that
    the horizontal guide plates (8) located on both sides of the guide vanes (5) are constructed with an overlap area (14).
13. Mill classifier according to claim 12,
    characterized in that
    the horizontal guide plates (8) located on both sides of the guide vanes (5) are positioned in such a way that they are superimposed with a limited spacing in the overlap area (14).
14. Mill classifier according to one of the claims 3 to 13,
    characterized in that,
    at least on their incident flow side (15), the horizontal guide plates (8) are constructed in wear-resistant manner.

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