EP0155537A2 - Device for cleaning semolina - Google Patents

Abstract

In the case of an apparatus for cleaning grits, which has a plurality of superimposed screen layers, which can be vibrated by means of at least one unbalance exciter and with an inlet or outlet for the product inlet or screen discharge arranged at one end, collecting means with adjustable setting flaps for the screenings, as well as an air circulation through the screen layers over an air distribution chamber in a suction collecting channel adjustable by means of adjusting flaps, it is provided that the apparatus is constructed as a stand with a stand head, a stand base and a vertical intermediate support connecting said two parts, the screen layers being constructed as a dust box and being vibratably supported in the vicinity of the stand base, the stand top being formed by the upper air distribution chamber.

Description

The invention relates to a device for cleaning semolina, with vibrating, superimposed screen layers and each arranged on one end inlet or outlet for the product inlet or the screen rejection, and with collecting devices under the screen layers for screen diarrhea and a means Adjustable flaps adjustable air flow through the sieve layers and through an upper air distribution space in a suction channel.

Such devices for cleaning semolina are special machines that are used almost exclusively in grain milling. They are used to sort out semolina and dun and occasionally maize semolina from the product fed to the machine, with the aim of achieving the highest possible yield of clean semolina.

In the case of conventional semolina cleaning machines, the sieve diarrhea was previously thrown from the lower sieve layer directly into the collecting devices. The sifter air sucked in under the lowest sieve layer for cleaning the semolina influences the sieving diarrhea (semolina) that trickles down there with regard to its falling behavior, whereby, for example, a lateral blowing away of the sieve diarrhea, changes in the falling speed, turbulence or the like. can occur. An increase in the cleaning performance, which causes an increase in the amount of air sucked in for the flow through the sieve layers, then leads at the same time to an increased disturbance of the trickling sieve diarrhea, so that there are narrow limits to an increase in performance of the known cleaning devices if one does not want to accept considerable cuts in the quality of the semolina obtained. In addition, the problem-free operation of the known semolina cleaning machines can be influenced noticeably and undesirably by the penetration of disturbing air from the machine environment into the area of the air intake and the trickling of the sieve diarrhea.

Proceeding from this, the object of the invention is now to develop a semolina cleaning machine which, compared to known semolina cleaning machines, permits a further increase in product performance and has an improved immunity to interference from external air disturbances from the machine environment.

According to the invention, this is achieved in a semolina cleaning machine of the type mentioned at the outset in that an oscillatingly mounted floor with a plurality of outlets directed toward the collecting devices is arranged between the bottom sieve layer and the collecting devices, forming a lower air distribution space for air intake.

With the solution according to the invention, a defined lower air distribution space is now created for the first time, and the individual fractions can be derived underneath this space and separated from it by the floor undisturbed. The invention thus enables a functional separation between the air intake and air distribution on the one hand and the collection and discharge of the sieve diarrhea on the other hand, which allows an optimized adjustability of the overall machine and an increase in performance in a wide range with very good grit quality and yield. The air supply on the one hand and the division of the fractions on the other hand is carried out in two spatially separate steps and thereby the occurrence of undesirable influences from cross air from the environment or the like. almost completely excluded.

In a device according to the invention, lateral air intake gaps are preferably formed between the bottom and the sieve layers are advantageously in the order of a few centimeters gap width. This enables possible interference from outside, for example the occurrence of strong local air currents (draft) from the machine environment, to be eliminated, since these interferences due to such air intake gaps are practically no longer effective. In order to ensure the best possible and sharp separation into the individual fractions, in a further advantageous embodiment of the invention, the bottom is designed as an inwardly inclined conveyor trough which has product steering flaps assigned to the outlets in its central lower section. The floor is preferably provided with individual trough-shaped depressions corresponding to the number of product steering flaps, which open out into the outlets and can optionally be directed into different collecting devices by the product steering flaps. The product steering flaps are preferably designed as chutes that can be tilted about one articulation point. It is particularly advantageous here if the cross section of the outlet opening between the chutes and the floor is smaller than the cross section of the air intake gaps.

Since the air flow seeks the path of least resistance within the machine, a suitable air flow is always ensured in the solution according to the invention, the area of the product discharge remaining free of any disruptive air flow.

The semolina cleaning machine according to the invention is preferably designed as a double machine.

An advantageous embodiment of the invention is also that. a collecting device designed as a double conveyor trough and capable of swinging in the same direction as the double layer is provided, which is supported so as to be able to oscillate independently of the sieve layers, which makes it possible to choose an oscillating movement for this double conveyor trough that does not match the oscillating movement of the sieve layers, i.e. different from that of the sieve layers.

It is particularly advantageous if the sieve layers and the bottom are designed as an oscillatable structural unit. Conveniently this unit consisting of sieve layers and base is supported on the two end sides so that it can swing. The measure already described is particularly advantageous here, namely that the sieve layers and the double vibrating conveyor trough are driven by a common unbalance exciter, which is firmly connected to the sieve layers and whose direction of force can be set. The double vibrating conveyor trough can advantageously be driven by the oscillatable unit via a lever joint in order to increase the oscillation stroke, in that the double conveyor trough can be set in vibration by means of a drive lever and a support from an end support of the sieve layers, the articulation points of this lever both on the end support as on the support to adjust the throwing distance can be changed. As a result, the oscillation deflection of the double conveyor trough can be selected independently of the oscillating movement of the sieve layers, although this is done with the same unbalance exciter.

The device according to the invention allows a clean guidance of the product as well as an excellent distribution of the air, whereby not only the quality of work, but also the product performance of the device can be significantly increased compared to previously known semolina cleaning machines.

In the device according to the invention, the process of discharging the individual sieve diarrhea fractions is moved into the corresponding collecting devices in a machine area which is completely separated from the area of the incoming working air and therefore cannot be undesirably disturbed or influenced by it.

• Fig. i eine Längsansicht einer erfindungsgemäßen Vorrichtung;
• Fig. ₂ den Schnitt 11-11 aus Fig. _I;
• Fig. ₂a eine Detail-Prinzipdarstellung für eine gegenüber Fig. ₂ geänderte Ausbildung von Schwingboden und Luftzuführung;
• Fig. ₃ die kombinierte Abstützung der Sieblagen auf Federn und des Schwingbodens auf einem Hebelgelenk (in prinzipieller Darstellung);
• Fig. ₃a eine prinzipielle Detaildarstellung eines Abschnitts eines Schwingbodens mit Produktauslässen;
• Fig. ₄ eine schematische Darstellung der variierbaren Möglichkeiten einer Kraftübertragung von den Sieblagen an den Schwingboden (Schwingförderrinne) bei einer erfindungsgemäßen Vorrichtung;
• Fig. 5 eine schematische Darstellung des oberen Luftteilraumes bei einer erfindungsgemäßen Vorrichtung, und
• Fig. 6 eine Schnittdarstellung längs IV-IV in Fig. 5.

The invention is explained in more detail below in principle on the basis of the drawing. Show it:

• I shows a longitudinal view of a device according to the invention;
• Fig. _{2 shows} the section 11-11 of Fig. _I ;
• FIG. ₂ a shows a detailed illustration of the principle for a design of the oscillating floor and air supply that has been changed compared to FIG. ₂ ;
• _{3 shows} the combined support of the sieve layers on springs and the vibrating base on a lever joint (in a basic representation);
• ₃ a shows a basic detailed illustration of a section of an oscillating floor with product outlets;
• FIG. _{4 shows} a schematic representation of the variable possibilities of power transmission from the sieve layers to the vibrating floor (vibrating conveyor trough) in a device according to the invention;
• Fig. 5 is a schematic representation of the upper air compartment in a device according to the invention, and
• 6 shows a sectional view along IV-IV in FIG. 5.

First of all, reference is made to FIGS. I and ₂ , in which (as in the other figures) a so-called “double machine” is shown, which consists of two semolina cleaning machines that are completely separate in terms of working technology, as shown in FIG. ₂ . These two semolina cleaning machines are arranged on the left and right with respect to a central stand construction.

In Fig. I one can see on the top left an inlet i for the product to be fed to the device and on the bottom right outlet ₂ for the screen rejection. Furthermore, three screen layers ₃ arranged one above the other are provided, an inner collecting device ₄ and an outer collecting device _{5 being} arranged beneath them (FIG. ₂ ), in which the sieve diarrhea is collected. As a rule, each individual collecting device ₄ or 5 has two processes 6 or ₇ . The sieve layers ₃ are combined to form a cleaning box 8 (FIG. ₂ ), so that each cleaning box 8 is assigned two outlets ₂ for the screen rejection and four outlets 6 and ₇ for the screen diarrhea in accordance with the illustrated embodiment. Each cleaning box 8 is via an end support ₁₂ (FIG. I) via oscillating elements or hollow rubber springs ₁₃ on a stand base 10 Stand ₉ supported swingable. With the end support _12, an unbalance exciter ₁₄ is fixedly connected to the thrust (see FIG. Arrow 15 in Fig. I) by rotating the Unmwuchterregers ₁₄ on a tubular cross-connection is adjustable ₁ 6. Likewise, what is known can regulate the strength of the unbalance forces by appropriate adjustment of the unbalance weights ₁₇ . At the cross connection ₁ 6 two unbalance exciters _{14 are} attached and electrically connected so that they rotate in opposite directions. So that their lateral Unwuchtkomponeten cancel out and there is a purely linear longitudinal vibration in the direction of arrow 15. About the unbalance exciters ₁₄ is mounted a cover ₁ 8, which is designed for structural simplification as a part of the vibrating system.

The collecting device ₄ is designed as a vibrating conveyor trough, which rests on both end sides on a support 19 mounted in rubber (FIG. I). The oscillation drive of the collecting device ₄ takes place via a lever ₂₀ which connects the oscillating end support ₁₂ to the support 19. Depending on the height of the point of application of the lever ₂ o on the support 19 (this height can be adjusted), the swing stroke of the collecting device ₄ can thus be selected or adjusted independently of the swing stroke of the cleaning box 8. The stand ₉ carries all non-vibrating components directly, the vibrating elements being mounted above the lower part of the stand. The stand _{9 also} has a vertical support ₂₁ on each end side (FIG. ₂ ), which merges into a foot construction at the bottom via an extension. According to the illustration in FIG. _2, the vertical support ₂₁ extends a little beyond the uppermost sieve position and supports the stand head 11, which essentially forms the upper air distribution space ₂₂ . This upper air distribution space ₂₂ has an upwardly tapered shape and is divided over its length by bulkheads ₂₃ into sixteen separate air guiding chambers ₂₄ . The bulkheads ₂₃ , as can be seen in FIG. 1, are brought close to the uppermost sieve layer, the distance being chosen so that it is somewhat larger than the greatest layer thickness of the material that ever occurs.

The upper inclined surfaces of the air distribution space ₂₂ have transparent windows ₂₅ over their entire length (FIG. ₂ ), so that with one electrical light source from the outside of the device, the flow behavior of the material over the top sieve layer ₃ can be controlled. In Fig. ₅ it can be seen between the upper end of the Luftverteilraumes ₂₂ and a Absaugsammelkanal Verstellklappen _{27 2} 8, such as ₅ and 6 can be seen from Fig., the respective air requirement can be set in accordance with a head _29.

• beim Stand der Technik sind nämlich die Umlenkklappen direkt auf der Auffangvorrichtung ₄ bzw. 5 angebracht, wodurch eine Hälfte der betreffenden Auffangvorrichtung andauernd zugedeckt wird, was dazu führt, daß sich unter ihr abgesperrte Schmutzecken ausbilden können, was wiederum bei der Erfindung nicht eintreten kann, da dort diese Abdeckung entfällt. Noch ein weiterer merklicher Vorteil der erfindungsgemäßen Vorrichtung besteht auch darin, daß der Siebdurchfall sehr exakt in die gewünschten Fraktionen aufgeteilt werden kann, weil störende Luftströmungen in Längsrichtung so gut wie ausgeschaltet sind.

As can be seen from Fig. _2, is provided between the flush-mounting box 8 and the procedures 6 and _7, a swingably Supported out at the stand base 10 bottom ₃₂ is provided which has over its length a plurality of recesses ₃₃ having outlets ₃ 6, the bottom in each case via a product longitudinal flap or chute ₃₄ (Fig. ₂ and 2a) can be aligned to the inner or outer collecting device 4 and 5, respectively, so that the sieve tailings, as desired, derived either in one or in the other collecting device below the sieve layers ₃ can be. The number of product longitudinal flaps ₃₄ is preferably selected to be approximately the same size as the corresponding number of air guiding chambers ₂₄ . From Fig. ₂ it can also be seen that the working air flows over air intake gaps ₃₅ provided on both sides, but which, as shown in Fig. ₂ a, can also be provided only on the outside of the floors ₃₂ . These measures bring various advantages: on the one hand, the guidance of the air flow is completely separate from the product discharge, which takes place below each floor ₃₂ , where there is no more air flow. On the other hand, the air flowing in from the side causes the product stream falling onto the bottom ₃₂ to be deflected towards the center of the bottom, where the chute _{34 is} arranged, thus “concentrating” towards the inside. In addition, the product flow has a certain self-cleaning effect in the device:

• in the prior art, namely, the deflection flaps are mounted directly on the collecting device ₄ or 5, as a result of which half of the relevant collecting device is covered continuously, which means that dirt corners which are shut off can form below it, which in turn cannot occur in the case of the invention, since there is no cover. Yet another noticeable advantage of the device according to the invention is that the sieve diarrhea can be divided very precisely into the desired fractions, because disturbing air flows in the longitudinal direction are virtually eliminated.

When the semolina cleaning machine shown is started up, the vibrator is switched on, so that the cleaning box 8, the bottom ₃₂ and the collecting devices 4 and ₅ carry out the preselected oscillating movement in the longitudinal direction of the device. Likewise, the entire device is placed in a slight negative pressure via the suction collecting duct ₂₇ or an aspiration associated therewith. Depending on the separation task, all slides and flaps are provisionally adjusted, after which the product can be fed into the inlet i. The product immediately falls on the top sieve layer ₃ . Due to the shaking movement, which is imprinted on the material, as well as through the sieve layers which are deliberately inclined downwards from the inlet i to the outlet ₂ and through the air flow through the sieve layers ₃ , the product behaves like a liquid (fluidized). The central task of the semolina cleaning machine lies in the actual sieving process. So the air flow must not be adjusted so much that the entire product layer could be lifted off the sieve layers. Rather, the air primarily serves the function of loosening up the product and distributing it evenly over the entire surface.

Depending on the task, it is required that the product should be fractionated into coarse, medium and fine size or into cooking size and medium size etc. In the second case, e.g. B. the first six chutes can be directed into the collecting device ₄ , the subsequent eleven chutes into the collecting device ₅ . In this case, the two sieve passes are finished products that can be delivered to the corresponding storage cells or to the consumers. The screen rejects at the outlets are partially regrinded or crushed and then transferred to a second, appropriately set, grit cleaning machine.

The specific sieve mesh sizes suitable for the respective task must be selected in each semolina cleaning machine.

Once the semolina cleaning machine is in full operation, the miller's actual task begins, namely the assessment of the functioning of the device and the quantitative and qualitative assessment of the fractions obtained.

For this purpose, the light source ₂ 6 (Fig. ₂₎ is turned on, so that the entire room is illuminated within the Luftverteilraumes. The flow behavior of the product within the individual air guiding chambers ₂₄ can be observed over the entire length through the windows ₂₅ . Is shown within one or more Luftführungskammren _24, an image similar to the boiling water, so the amount of air is throttled in the relevant air duct ₂₄ through the chambers Verstellklappen _2. 8 Conversely, a congestion can also occur at individual points: here the local air volume must be increased accordingly. If the flow behavior of the product is flawless and if there are no parts in the mixed product (outlets) that belong to sieve diarrhea, the quality of the sieve diarrhea is checked again and the chutes _{34 are} adjusted to the correct collecting devices ₄ and ₅ , respectively.

As can be seen from FIG. 1, two different processes 6 and ₇ can be selected from each collecting device ₄ or ₅ , so that four different fractions can be separated from each cleaning box 8.

FIGS. ₅ and 6 show an advantageous embodiment with respect to the used Verstellklappen ₂ 8 which are designed as a slide. These sliders allow more precise adjustment of the air requirement in all slider positions. A proportional change in cross-section of the slide opening is caused in accordance with the revolutions of the head ₂₉ . If a flap were used instead of a slider, a similar, proportional cross-sectional change would no longer occur here, since in such a case the effective opening cross-section would no longer change in proportion to the rotation of the head ₂₉ . The slide solution also has the further advantage that the free cross section of the suction collecting duct ₂₇ is not influenced by the different open positions of the slide.

In the solution according to FIGS. ₅ and 6, it has been shown that the suction collecting duct ₂₇ can be designed with a constant cross section in the air flow direction.

In Fig. ₃ , the support of the vibrating unit is shown on a rubber joint ₄₂ , which is embodied by a spring system ₄₀ .

The unbalance exciter ₁₄ can, as shown in FIG. ₁ can be seen to a transverse axis ₁ 6 are rotated, so that either the force effect device ₄₁ is adjustable, as indicated by the arrows in Fig. _3. If the direction of the force action passes through the center of gravity of the vibrating unit, a uniform vibration of the entire sieve stack is generally achieved. However, if the direction of force ₄₁ does not run through the center of gravity, then - depending on the particular requirements - an actual vibration can be set in the area of the inlet i in accordance with an angle and in the outlet _{2 in} accordance with another angle.

Figs. ₃ and ₄ provide a total of a particularly advantageous embodiment in principle is: the cleaning box 8 is defined herein as real cantilever on a spring system ₄ o or a steel spring ₄₂ mounted for oscillation. The unbalance vibrator _{14, which} is adjustable with respect to the direction of the force action, is fastened to the end support ₁₂ and, by using two counter-vibrating vibrators, brings about an essentially purely linear oscillating movement analogously to the illustration from FIG. I. The collecting device ₄ , ₅ is mounted on a support 19 so as to be able to oscillate independently of the cleaning box 8. The end support _{12 is} connected to the support 19 via a lever ₂₀ , so that the vibrations of the unit which is supported transversely via the spring system ₄₀ can be transmitted to the catch device ₄ , ₅ via the lever ₂₀ . The lever ₂₀ can be attached to the support 19 at different heights xi, x2, ... x6 (cf. FIG. ₄ ). This creates the possibility, starting from the drive of the unbalance vibrator ₁₄ via a correspondingly selected and adjustable lever path, to trigger or force different lateral oscillation deflections of the collecting device ₄ , ₅ , thereby obtaining a surprisingly simple oscillating structure. The sieve stack carries out a short-lived vibration for the "sieving" task, while the collecting device carries out a long-lasting swing-throwing movement in accordance with the function of a vibrating conveyor trough, which is carried out by the correct articulation of the Lever ₂ o is supported on the support 19. The work result of this combined cantilever lever arm has proven to be surprisingly good.

FIG. ₂ a shows a shape of the vibrating base for the left half of a double machine that is modified from FIG. ₁ , in which the bottom sieve layer _{3 is designed} with the vibrating base ₃₂ as a structural unit. The air intake gap _{35 is} provided only on the outside of the machine (thus in FIG. ₂ a: left). The lowest of the sieve layers ₃ is attached directly to the upper edges of the bottom ₃₂ . The lower part of the bottom ₃₂ converges towards an outlet ₃ 6 on which a pivotable chute 34 is arranged, can be discharged by means of the incoming there Good optionally (not shown) arranged underneath the collecting devices.

The detail section of FIG. ₃ a shows an enlarged section of the device from FIG. ₃ in the area of the oscillating floor. In this case, a plurality of adjacently disposed trough-shaped outlets ₃ 6 are shown below in the sprung floor _32, a chute is mounted pivotably in the manner already described ₃₄ on each of which below. Above the outlets ₃ of the 6 Luftansaugspalt ₃₅ is shown extending over the entire length of the bottom of _{the 32nd}

Claims (9)

i. Device for cleaning semolina, with vibrating sieve layers ( ₃ ) arranged one above the other and an inlet (r) or outlet ( ₂ ) arranged on one end side for the product inlet or sieve rejection, collecting devices ( ₄ , ₅ ) under the sieve layers ( ₃ ) for the sieve diarrhea and an air duct which can be adjusted by means of adjusting flaps through the sieve layers ( ₃ ) and via an upper air distribution space ( ₂₂ ) into a suction collecting duct ( ₂₇ ), characterized in that between the lowest sieve layer ( ₃ ) and the collecting devices ( ₄ , 5 ) with the formation of a lower air distribution space (22 ') for the air intake, a floor ( ₃₂ ) with an oscillating bearing and a plurality of outlets ( _3, 6) directed towards the collecting devices ( ₄ , ₅ ) is arranged. _2nd Device according to claim i, characterized in that lateral air intake gaps ( ₃₅ ) are formed between the bottom ( ₃₂ ) and the sieve layers ( ₃ ). _3rd Apparatus according to claim I or ₂ , characterized in that the bottom is designed as an inwardly inclined conveyor trough ( ₃₂ ) which has product steering flaps ( ₃₄ ) assigned to the outlets ( ₃ 6) in its central lower section. _4th Device according to claim ₃ . characterized in that the base ( ₃₂ ) has individual trough-shaped depressions ( ₃₃ ) corresponding to the number of product steering flaps ( ₃₄ ) which extend into the outlets ( ₃ 6) open and can be emptied through the product steering flaps ( ₃₄ ) optionally into different collecting devices ( ₄ , 5). 5. Apparatus according to claim ₃ or ₄ , characterized in that the product steering flaps are formed as chutes which can be tilted about a respective pivot point ( ₃₄ ). 6. Device according to one of claims i to ₅ , characterized in that the screen layers ( ₃ ) and the bottom ( ₃₂ ) are designed as a vibratable unit. ₇ . Apparatus according to claim 6 with an unbalance exciter ( ₁₄ ) for generating the vibrations of the sieve layers ( ₃ ), characterized in that the sieve layers ( ₃ ) and the bottom ( ₃₂ ) are firmly connected to the unbalance exciter ( ₁₄ ) and its direction of force action ( ₄₁ ) is adjustable. 8. Device according to one of claims i to ₇ , characterized in that a in the same direction to the sieve layers ( ₃ ) oscillatable, designed as a double conveyor trough ( ₄ , 5) is provided, which is supported independently of the sieve layers ( ₃ ). 9. The device according to claim 8, characterized in that the double conveyor trough ( ₄ , ₅ ) from an end support ( ₁₂ ) of the screen layers ( ₃ ) via a drive lever ( ₂₀ ) and a support ( ₁₉ ) can be set in vibration, the articulation points the lever ( ₂₀ ) on the end support ( ₁₂ ) and on the support ( ₁₉ ) can be changed to adjust the throwing distance.

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