DE102012108907B4 - Method and device for dedusting bulk materials by means of ionization - Google Patents

Abstract

A process for dedusting a granulate (4), wherein the granulate (4) is fluidized in a granular container (9) and during the fluidization ionized gas (34) is introduced into the granule container (9) and at the same time the dust (11 ) is separated from the granules (4) by the dust (11) from the granules container (9) is sucked off, characterized in that during the dedusting of the granules (4) in the granular container (9) in the lower region of the granule container ( 9) existing granule opening (25) is kept closed.

Description

I. Field of application

The invention relates to the dedusting of bulk materials by means of ionization.

II. Technical background

Especially in plastics technology, but also in pharmacy - and food technology, often raw materials in the form of bulk materials, such as granules, grindings, coarse powders or the like. be handled. For the purposes of the present application, all bulk materials are referred to by the shortening term "granules".

Especially the transporting of these bulk materials is often carried out by means of compressed air conveyor technology, in which the granules are sucked by means of compressed air through delivery lines and brought to the desired location.

The granules should be as clean as possible for further processing, for example use as raw material in a plastic injection molding machine, and in particular should not be contaminated with dusty impurities. These dusty impurities may both consist of foreign material, which were inadvertently added to the granules during manufacture or during transport, or it may also be dust-like particles of the same material as the granules themselves, but this may also be undesirable depending on the subsequent use ,

Therefore, the general aim is to separate such granules before use from the dust content contained therein.

For this purpose, different techniques are available, from simple sieves over a separation of the transport air from granules and filters of the transport air to the fraction separation by means of a cyclone.

One of the problems encountered is the strong adhesion of dust particles and granular particles to each other, but also the adhesion of dust particles to device parts such as conveyor lines or granules containers.

This strong adhesion is often caused by electrostatic charging, so that removal of the dust with mechanical measures can usually be performed only when these binding forces, especially the so-called Lorenzkraft have been repealed.

In principle, this is known to be possible in that the differently charged and thus attracting parts, in this case dust particles on the one hand and granulate particles on the other hand, respectively, are discharged, for example by the one fraction is grounded.

With a very large number of very small particles, as in the present case, this is hardly possible in practice.

From the EP 0616856 B1 , which represents the next state of the art, as well as the WO 2004/049884 A2 It is known that granules fall down in a dedusting chamber and thereby repeatedly bounce on baffles, while an upwardly flowing gas stream to remove the dust particles present in the granules upwards.

This is supported by introducing ionized gas into the dedusting chamber in the former specification, and in the second-mentioned document the baffles are ionized.

From the DE 102009013220 A1 a similar solution is known in which, however, in the high, upright Entstaubungskammer no baffles are present, but the granules gravitationally fall down and the dust particles are to be dissipated by the countercurrent gas flow upwards. In the feed for the granules, an ionization is arranged.

From the EP 181811182 It is also known to drop the granules on the sieve bottom of a Entstaubungskammer, and to press an air flow through this bed of granules and the sieve bottom, which is to dissipate the dust particles through the sieve bottom with.

Furthermore, from the WO 2004/048006 , which forms the closest prior art, an air classifier in the form of a perforated plate drum known, which is arranged in a frontally open container. The closed on one end face and open on the other side perforated metal drum is arranged in an analog housing and therein about its axis of symmetry. In addition, the entire housing is pivotable about a transverse axis between filling position, operating position and emptying position. Therefore, the one end opening is both filling opening and removal opening for the granules to be dedusted by this top opening when filling, when emptying down.

In the operating position, the axis of symmetry of the perforated plate drum is horizontal and the granule opening is located laterally on the Face. In this operating position, air is blown in from the first air outlet openings below the screen drum and, on the other hand, air is also blown through the granule opening pointing to the side, causing the granules in the screen drum to be swirled up. At a high in this operating position air outlet, the dust-laden air is sucked out of the housing.

This construction is mechanically complex and susceptible to wear, since all inlets and outlets must join the pivoting movements between the individual operating positions, and must therefore be made flexible and thus susceptible to wear.

III. Presentation of the invention

a) Technical task

It is therefore the object of the invention to provide a method and a device for canceling the binding forces between dust particles and granules particles available, which work simply and inexpensively.

b) Solution of the task

This object is solved by the features of claims 1 and 13. Advantageous embodiments will be apparent from the dependent claims.

These binding forces are canceled according to the invention by the procedure that an ionized gas, in particular ionized air, is brought into contact with the granules and preferably brought into contact with the entire granules.

If the granulate is batchwise dedusted in a container, the ionized gas is introduced into the container. However, in a continuous treatment process, the ionized gas can be applied to the granules also permanently, for example in a continuous process.

The ionized gas can be generated in different ways, but according to the invention preferably by means of an electric arc, which is maintained at an applied voltage of 2 to 8 kilovolts.

The mode of action is that yes, the dust particles adhere strongly due to their positive or negative electrical charge, especially on the electrically non-conductive granules. Now, when an oppositely charged ion of the ionized gas comes into contact with such an electrically charged dust particle, the mutual charges neutralize, and the strong adhesive force of the dust article is lost, so that the dust particles can be easily detached from the granule particles and, for example, by air sifting or another method, the dust from the granules can be separated.

If a sufficiently large amount can be made available to ionized gas per unit time, the granules can also be treated in a continuous flow, that is, for example, continuously through a curtain of ionized gas.

As a rule, however, a purified granules is not constantly required with a large throughput per unit time, the granules to be cleaned of the dust is preferably treated batchwise by a certain amount of unrefined granules is introduced into a granular container and dedusted there. For this purpose, the granule container is only partially filled with granules, u.a. because, due to the granules located in the lower area of the granulate container, fluidization of the granules and distribution in the entire granulate container can occur due to injection of compressed air.

The removal of the binding forces between dust and granules requires that the ionized gas reaches as far as possible the entire granules received in the granulate container. This is favored by different measures:
On the one hand, the ionized gas is introduced into the granulate container at a pressure above atmospheric pressure, in particular at 3 bar to 5 bar overpressure.

Each region within the granule container can also be achieved by the ionized gas in that the introduction of the ionized gas in the granule container via a hollow supply body, which is approximately matched in its contour of the inner contour of the granule container, ie to the walls everywhere in about maintains equal distance, or extends through one of the walls of the granule container into its interior and extends along the largest extent of the granule container over more than 60% in this direction, preferably in the center of the granule container viewed in the direction of the feed body.

The supply body may be a simple, preferably closed at the front end, tube. In any case, the supply body for the ionized gas must be penetrable, for example by having a plurality of passage openings in the walls and also in the closed end side of the supply body.

In order to be able to dedust reliably even with a relatively small amount of ionized gas produced per unit of time, the granules in the granules repeatedly, preferably with waiting time in between, swirled up and brought the granules with the ionized gas in contact. For this purpose, ionized gas is introduced into the granule container before it is swirled up and a high density of ions in the granule container is produced over the duration of introduction, which also penetrate into the deposited granules, but only up to a certain depth, but when the granules are stirred up very many, preferably all, granules particles come into contact.

Also, during the fluidization, ionized gas is preferably further introduced into the granule container. The fluidization is preferably carried out by injecting compressed air into the granules deposited in the granulate container, wherein the compressed air has a higher pressure than the introduced ionized gas, preferably namely an overpressure of 5 bar to 7 bar.

The production of ionized gas, preferably ionized air, is preferably carried out during the entire phase of the multiple successive swirling and the waiting times in between, to preserve the life of the ionizer, which decreases by frequent switching, especially if the ionization by means of an electric arc happens because then the arc tip wears faster.

The introduction of ionized gas can also take place when filling the granule container, but this is not the decisive point because of the short filling time.

Since the arc tip also works worse and worse, the more impurities the gas to be ionized in the form of solids or liquids, the ionized gas is preferably purified before the ionization of solid contaminants and / or liquid impurities, especially oil, which is in particular then it is necessary if the gas to be ionized is provided by the compressed air network provided by a conventional compressed air and reduced in terms of pressure only to the extent necessary compressed air.

Nevertheless, the ionizing tip must be cleaned at intervals. This can be done either whenever a visual inspection through a window of the granular container shows that dust is present despite ionization and aspiration of the air, or cleaning takes place at fixed maintenance intervals, e.g. determined in operating hours of the ionizer.

The separation of the dust from the granules - and also from the inner walls of the granule container - is carried out according to the invention preferably by sucking the air, which is in the granule together with the dust through a sieve, which can be penetrated by the dust, but not by the granules.

Preferably, at least when sucking the air, the granule inlet opening of the granule container is not closed in order to avoid the build-up of a negative pressure.

The closable granule opening present in the lower region of the granulate container is kept closed during the introduction of ionized gas and dedusting, that is the aspiration of the air after the granules have been fluidized, in order to make the same batch of granules multiply by the multiple fluidizing and sucking off of air edit one after the other, so you can dust off.

How many Aufwirbelungsvorgänge in a row and with what waiting times are performed in between depends on the type of granules and in particular its dust content and / or adhesion and / or electrostatic charge.

The number of revolutions of a batch of granules is usually between 1 and 5 times. The duration of each rejuvenation process is between 1 s and 5 s.

The agitation of the granules by means of compressed air and the introduction of ionized gas is usually carried out via separate openings, but both can be functionally combined by the pressure at which the ionized gas is introduced, and the point of introduction into the granules so be chosen so that thereby a Aufwirbelung of the granules takes place in the container. Possibly. For this purpose, the pressure of the introduced ionized gas is also varied, in particular varies periodically, so that alternately Aufwirbelung takes place or not.

Likewise, the time between the Aufwirbelungsvorgängen, so the waiting time, during which usually continuous ionized gas is introduced, each between 2 seconds and 20 seconds, in particular between 3 seconds and 10 seconds.

In general, between 100 l and 100 l of ionized gas per 100 ml of de-dusting granules should be used, e.g. be introduced into the granule container.

The fact that air is sucked out of the granule container together with the dust is usually achieved by generating the necessary negative pressure in the suction line by means of compressed air and the required compressed air as well as the air which is ionised and / or the air to stir it up Preferably, all of the granules are taken from the same source of compressed air, and adjusted only by pressure reducing valves to the necessary pressure at each consumption point, in particular for the gas to be ionized.

To carry out the dedusting method described so far, a device is needed which initially - as usual for batch treatment - has a granular container having a Granulateinlassöffnung and a Granulatauslassöffnung and beyond an outlet opening for sucking the air together with the dust to be removed.

According to the invention, the device further comprises a hollow supply body for the ionized gas, which is at least partially in the interior of the granule container and has passage openings in its wall for the exit of the ionized gas into the granule container.

The supply body must be designed and dimensioned such that the ionized gas flowing out of it reaches as far as possible all the areas in the interior of the granulate container and preferably uniformly strongly pressurizes it with ionized gas.

The supply body is connected to a gas supply, in which an ionizer is arranged, which in particular comprises an electric arc.

Preferably, the ionizer is arranged as close as possible to the granule container.

In order to regulate the pressure in the gas supply and thus in the supply of ionized gas in the granule container, a pressure control valve is further preferably arranged in the gas supply.

Preferably, the gas supply is a compressed air supply, wherein the compressed air is preferably fed from the same compressed air source as the compressed air for stirring up the granules and / or the compressed air for conveying the granules into the granule container.

The Granulatauslassöffnung is closed, preferably with a granule flap, and is usually in the bottom of the granule container, so that after opening the Granulatauslassöffnung the granules therein can gravitationally fall out.

A further final granulate container can be arranged under the granulate container so that the container previously known as "granulate container" is then only a granulate intermediate container.

The final container thus serves as a storage buffer for dedusted granules, and dedusting is continued with additional batches in the intermediate container as soon as the level falls below a predetermined minimum in the final container.

For this purpose, at least one level sensor for a minimum filling quantity and possibly also a filling level sensor for a maximum filling quantity are contained in such an end container, for example capacitive sensors which detect the fill level through corresponding windows.

The supply body may be a simple round tube with a closed end face and passage openings in the walls as well as in the end face of the tube, or the feed body may be contoured to the contour of the inner walls of the granule container, so preferably the distance between both at all locations is substantially the same, and differs by more than +/- 10% or +/- 20%.

When the granule container is more tall than wide, which may be the most common case for reasons of space, the supply body extends either from the top closing lid down into the granule container or through the bottom, and extends upwardly.

The latter has the advantage that the supply body and thus outlet openings for the ionized gas are present directly in the granules deposited in the lower region, the disadvantage, however, is that in the lower region, the fluidizing fluidized-pressure jet is present for stirring up the granules, and when swirling the granules strikes very strongly against the supply body and this is therefore subject to heavy wear, especially when individual outlet openings of this compressed air-Aufwirbelungsdüse are directed to the supply body.

One possibility, therefore, is to let the supply body run near or directly along that wall, for example the front wall, of the granulate container in which the fluidizing compressed-air nozzle is located.

In order for the supply body on the outside to withstand the highly abrasive effects of the granules for a long time, it often consists of a hard material, preferably of steel or stainless steel. As the touch of the ions with such Metal part immediately leads to a neutralization of the charge, the supply body consists at least on its inner side of an electrically non-conductive material, in particular plastic. In a supply body made of stainless steel this carries at least on the inside a coating of such a non-conductive material.

As ionized gas, air does not necessarily have to be used, but this is a simple and inexpensive solution. When using other ionized gases, they may be heavier or lighter than air, and accordingly, with an ionized gas heavier than air, the feed body may preferably protrude from above into the granule container or with an ionized gas that is lighter than air protrude down into the granule container, since the gas then flows in the other direction by itself.

In order to make the device small and compact, a granule container with a volume of less than 2000 cm ³ , in particular less than 1500 cm ³ , is used.

In such a granule container granules are usually filled in batches of 80 to 200 ml and dedusted.

In order to be able to visually control the effect of dedusting, the granulate container in a side wall, preferably the front wall, a window, preferably the air outlet opening of the granule container approximately opposite. In the air outlet opening a sieve is further arranged, which can be penetrated by dust but not by the granules, whereby the deposition of the granules is carried out in the deduster and thus the additional function of the granule separation is achieved.

Since the ionizer must be cleaned from time to time, it preferably has an hour meter and cleaning is set at cleaning intervals of a certain number of operating hours.

All relevant components, ie pressure control valve and / or shut-off valve in the gas supply, ionizer, closing device in the granule conveyor for granules in the granule container into it, for example, an ejector compressed air nozzle, level sensor in the granule end container and / or in the granular intermediate container or in the single Granule containers communicate with a controller that controls these components. The control is preferably able to control the waiting time between the Aufwirbelungsvorgängen, in which yes continues to be applied with ionized gas, as well as the number of Aufwirbelungsvorgänge, and the pressure at which the ionized gas is fed to the granule container as well the period of time with the beginning and end of the supply of ionized gas, in particular in relation to the time of refilling the granule container.

In addition, the granule container can be designed specifically by, for example, the wall of the vortexing compressed air opposite wall, usually the rear wall of the granule container is formed sloping upwards and reinforced on the outside, in particular with a metal plate to the heavy wear to resist the emerging from the fluidizing jet compressed air jet. This wear can be reduced by the Aufwirbelungsdüse has a plurality of nozzle openings, of which at least one, in particular a plurality of nozzle openings are directed obliquely upward, so not all are directed horizontally to the opposite wall.

If the granulate container is a granulate intermediate container, below which there is additionally a granulate end container, the intermediate granulate container can be folded down about an axis with respect to the granulate end container, and if the closure device closing the passage therebetween, for example the closure flap, thereby is attached to the lower container, the granulate end container, can be cleaned very easily from below after folding the granules intermediate container.

The feed line for granules into the granule container is preferably by means of a closure device, e.g. a closure flap, closable, which is also in particular connected to the controller and is controlled by this.

However, the ionized gas flowing out of the supply body can always leave the granulate container unhindered, namely through the outlet opening for air, which can not be closed, so that no disadvantageous high back pressure can arise in the granule container, which obstructs or even prevents the inflow of ionized gas.

In a granular container and two different delivery lines can lead to the delivery of different granules, which can then be mixed in the granule and can also be supplied in a certain mixing ratio.

c) embodiments

Embodiments according to the invention are described in more detail below by way of example. Show it:

1a a granulate separator with only one granulate container,

1b : a granulate separator with granulate intermediate container and granulate end container,

1c : the granule separator of 1b in the view from the back,

1d : similar to a granulate separator 1b in the side view,

1e : the granule separator according to 1d in the front view,

2a : the granule separator according to 1b with filled granulate intermediate container,

2 B the granule separator when introducing ionized gas into the intermediate granulate container,

3 : the granule separator when fluidizing the granules in the intermediate granulate container,

4 : the granule separator after emptying the intermediate granulate container,

5a : an overall view of a compressed air conveying system with granulate separator according to the invention during filling of the intermediate granulate container,

5b : the compressed air conveyor according to 5a when dedusting the granules in the granular intermediate container and

5c : the compressed air conveyor according to 5a after emptying the granulate intermediate container.

In 1a shows in side view a granule 1 with only a single granule container 9 in which a certain amount of granules 4 , such as in 2 can be seen, introduced and each dedusted such a batch:
The granule container 9 is tall format, so the height is the largest extension direction of the granule container 9 ,

The granules pass through a delivery line 15 in the granules container 9 in its removable lid 27 opens, which is the upper end of the granule container 9 forms.

The granules can the granules container 9 over the granule outlet opening 25 , preferably the entire bottom surface of the granule container 9 matters, leave again, taking this granule outlet opening 25 preferably closable.

In contrast to the straight and vertical front wall is the back wall of the granule container 9 inclined at the bottom, so that the cross section of the granule container 9 in this area down to the granule outlet opening 25 decreasing more and more. In the lower part of the front wall is a fluidizing air jet 28 arranged, via the compressed air to whirl up the granules 4 in the granule container 9 can be injected.

In the upper part of a side wall, here the rear wall, is an outlet opening 18 arranged, to which a dust line 20 connected, via which air from the granule container 9 can flow and in particular can be sucked out of this by in the dust line 20 an ejector compressed air nozzle 21 is arranged, preferably in the form of an elbow, which is a negative pressure in the dust line 20 generated.

By the outlet opening 18 from a sieve 5 is covered, which may be penetrated by air and dust, but not by the granules, the granules remain 4 in the granule container 9 of the granule separator 1 ,

To the dedusting of the granules 4 in the granule container 9 to improve, protrudes through the lid 27 a hollow supply body approximately in the middle of the section viewed in the plan view 35 in the form of a round tube 35 vertically down into the granule container 9 into it. Over passage openings 36 both in the walls of the feed body 35 and in particular in its closed end face may be an ionized gas 34 in the granules container 9 to be introduced:
For this purpose, the rear, outside the granule container 9 located end of the open feed body 35 In connection with a gas supply, in the course of which an ionizer 37 is arranged, which ionizes the gas flowing through it. In the gas supply are still a pressure control valve 38 and a check valve 40 arranged.

In the front wall of the granules container 9 is also a window 8a densely incorporated, which serves different purposes:
Firstly, in the middle region of the height of the granule container 9 on the outside of the window a capacitive level sensor 19a arranged when filling the granule container 9 detects when the desired level is reached, and the supply of granules 4 then via a controller 22 is switched off, which is also connected to all other on and off components.

Furthermore, the window is used 8a to do so by simple visual inspection in the granule container 9 to be able to observe whether and how well the dedusting of the granulate 4 it works in it.

1b shows a granule 1 , in which additionally under the now serving as granule intermediate container granules container 9 another granulate final container 14 is arranged by the granules 4 with open granulate outlet opening 25 can fall into it. In the granule final container 14 is a granule flap 6 attached, this granule outlet opening 25 can close by plant from below and also with the control 22 communicates.

On the front wall of the granule end tank 14 is again a window 8b incorporated, through which a level sensor 19b measures the level there.

1c shows the granule 1 according to 1b in the view from the rear, in which it is apparent that also the side walls of the intermediate granulate container 9 even if it is a single granule container 9 is, in the lower area obliquely down on the granule outlet 25 run.

1d shows in the same view as 1b one to the local granule 1 similar embodiment, in addition to the granule intermediate container 9 opposite the granulate end container 14 around a horizontal horizontal axis 24 can be tilted backwards. As can be seen, there is the granule flap 6 while continuing on the granulate end container 14 , so that in this tilted back position of the granular intermediate container 9 a lower open granule outlet opening 25 which is easily accessible for cleaning work inside the granulate intermediate container 9 from below.

1e shows this granule 1 in the view from the front, where there in the lid 27 two delivery lines 15 next to each other open for two different granules in the granule 1 to be mixed in a certain proportion, which also by means of the controller 22 can be done, the promotion in the two delivery lines 15 can switch on and off in the right relationship to each other.

The 2a , b and the 3 and 4 show now - the example of a granulate 1 with granulate intermediate container 9 and final granules 14 The different process conditions for dedusting a batch of granules 4 in the granulate intermediate container 9 :
According to 2a is first - with closed lower granule outlet 25 , so closed granule flap 6 - as long as the support line 15 granules 4 in the granule intermediate container 9 promoted, beyond the level sensor 19a a sufficient level is detected and the control of the further promotion of granules is stopped.

Maybe already with the beginning of the transport of granules 4 in the granule intermediate container 9 is started, via the feed body 35 ionized gas 34 in the granule intermediate container 9 to bring, as in 2 B shown. The ions of the ionized gas 34 distribute themselves in the air space above the granulate 4 , and penetrate something, but in smaller numbers, in the deposited granules 4 a, especially by exiting those passages 36 of the feed body 35 that accumulate in the deposited granules 4 are located.

After a predetermined time already the ionized gas 34 in the granule intermediate container 9 is introduced, is now in addition, so without interruption of the introduction of ionized gas 34 by injecting compressed air through the fluidizing air jet 28 the granules 4 in the entire granulate intermediate container 9 whirled up and distributed. At the same time in the granule intermediate container 9 air including the ionized gas contained therein 34 for a while through the sieve 5 sucked through. For this purpose, the suction line 20 subjected to negative pressure, for example by activating the ejector suction nozzle 21 ,

As a result of the fluidization of the granules, these and the dust particles adhering to them are much more likely to come into contact with one of the gas ions than in the deposited state of the granules 4 , Part of the dust particles will lose its electrostatic charge through contact with the gas ions and will detach from the granular particles and thus can be with the air in the dust line 20 be sucked off.

After completion of the Aufwirbelung stores the granules 4 again in the lower area of the granulate intermediate tank 9 ab, the introduction of ionized gas 34 will continue over a certain waiting time, and then again a Aufwirbelung with extraction via the suction line 20 carried out.

During the waiting time, the suction is carried out via the suction line 20 interrupted to the highest possible concentration of ionized gas 34 in the space above the deposited granules 4 to achieve. However, the waiting time must not be too long, because with increasing waiting time increases the probability that the ions of the ionized gas 34 For example, by contact with the usually made of stainless steel outer walls, so with an electrically conductive material, lose their charge and become electrically neutral.

Therefore - depending on the specific properties of the dedusting granules 4 , In particular its dust content, its static charge, its adhesion, its particle size and possibly other parameters - a variety of cycles of waiting and Aufwirbelung / suction are carried out in a row, including the duration of the waiting time, if necessary, and also the period for Aufwirbelung and suction , depending on the parameters of the granules 4 should be determined.

As in the illustrated arrangement, the compressed air shocks from the fluidizing air jet 28 partly directly and partly by reflection on the oblique rear wall of the feed body 35 this will be exposed to increased wear. For this reason, it may be useful to use the feed body 35 - such as in 5a shown - to run near or directly on the front wall in the area above the fluidizing air pressure nozzle 28 ,

Likewise, it may be necessary for the uniform distribution of the ions of the ionized gas in the granule container 9 or granule intermediate container 9 Make sense, the supply body so to the contour of the granule container 9 , so its interior surfaces, adapt that - as in 1a shown with dashed lines - the feed body 35 on all sides about the same distance to the walls of the granule container 9 occupies.

Whether the dedusting is successful and far enough advanced, can be achieved through simple visual inspection through the window 8a in the granule container 9 or granulate intermediate container 9 be noted, especially during the Aufwirbelung and suction of the granules 4 ,

If dedusting is sufficiently advanced, the dedusted batch can be opened by opening the granulate outlet 25 in the serving as a buffer for a downstream processing machine granular intermediate container 14 fall.

As a rule, from this point on and until reaching the next filling in the intermediate granulate container 9 the introduction of ionized gas 34 interrupted, but this is not absolutely necessary. Only if the stock in granules final container 14 over a longer period is sufficient, ie for a long time no new granules 4 in the granule intermediate container 9 is promoted for dedusting, it is highly advisable to use the ionizer 37 to protect, as this is subject to contamination and wear, and the ionizer 37 off.

The 5a -C show a complete compressed air conveyor system for a granulate:
The primary purpose is - as in 5a shown - a example granules 4 to transport to a desired location.

The granules 4 is doing in an open-topped reservoir 7 , For example, a bag or a barrel, delivered and the granules should be supplied in the required amount, for example, a plastic injection molding machine or previously a granular dryer.

There is often the need for several available storage containers 7 that different granules 4 contain, in a row briefly changing granules 4 in practice, in contrast to the 5a -C not one but several reservoirs 7 located next to each other.

The conveying takes place by means of suction of the granules 4 from the reservoir 7 eg with a suction lance 16 by means of conveying air 3 , which sucked the granules in the conveying air from the suction lance 16 over a usually designed as a hose delivery line 15 in the granule separator 1 conveyed, with its lower discharge opening 31 above the desired demand site, such as the injection molding machine is constructed.

In this case, there is the inside of the granule 1 , the granules collection area, from the granulate intermediate tank 9 above and the underlying granule end container 14 , with a closable granule flap 6 between.

The granule separator 1 otherwise corresponds to the design according to the 1 - 4 ,

From the outlet opening 18 becomes the conveying air 3 over a dust line 20 , which is again usually designed as a hose, a dust collector 12 supplied, in the outlet opening, a filter 2 to retain the dust content from the conveying air 3 located. The conveying air thus penetrates the filter 2 and exits into the environment while being in the dust line 20 in the conveying air 3 still contained dust 11 at the bottom of the dust container 12 settles.

The entire system is operated by compressed air, by also the negative pressure, which for the conveying air 3 is required, is generated by means of compressed air, by means of a transport ejector 21 who are building the 5a -C at the beginning of the dust line 20 , So in the dust outlet, the at the granulate 1 is arranged, is provided:
It is an elbow with a mostly nozzle-shaped outlet opening, which is installed, for example So in a side wall of the dust discharge nozzle, that the outlet opening of this transport ejector 21 is arranged centrally in the usually round cross section of the nozzle and compressed air in the flow direction 10 , So the direction of the dust line 20 in the direction of the dust collector 12 , which gives off upstream of the transport ejector 21 a strong negative pressure is generated, the over the granule intermediate container 9 and the support line 15 to the suction lance 16 acts back and at the free open end of a suction of granules 4 in the storage container 7 causes.

The required compressed air is supplied by a compressed air source 17 provided, which may be a separate air compressor or a connection to a larger compressed air network. Among other things, the delivery of compressed air to the individual points of the compressed air conveyor system is controlled by a controller 22 controlled:
With compressed air is also the granule flap 6 controlled, the granule opening 25 between the granules intermediate container 9 and the final granule 14 closes. In this case, in the absence of pressurized air, the granule flap 6 in the open state and is closed by means of compressed air.

The mouths of one or more delivery lines 15 in the top, namely the lid 27 , of the granulate separator 1 are each using a flap 32 lockable, the gravity-actuated applied to the bottom of the outlet opening.

5a now shows the funding process:
Here is the granule flap 6 closed by compressed air and via the transport ejector 21 Compressed air is supplied via these compressed air nozzles 21 leading unbranched compressed air line 26a injected.

Because the from the transport ejector 21 escaping compressed air serves to build up the negative pressure in the delivery line 15 and thus the suction of the granules 4 , The negative pressure upstream of the transport ejector 21 also ensures that the optional gravity-operated flap 32 opens, since in the presence of such a flap the only place the otherwise closed granulate intermediate container 9 is, from the air can flow, that of the transport ejector 21 is sucked.

In this way, the granules collect 4 at the bottom of the intermediate granulate container 9 more and more, while in the conveying air 3 existing free-floating dust content through the dust line 20 is dissipated.

Filling the granulate intermediate tank 9 takes place until the outside of the transparent window 8a in the front wall of the intermediate granulate container 9 arranged level sensor 19a a sufficient level in the granular intermediate container 9 to the controller 22 reports and this the compressed air supply to the transport ejector 21 off.

Now - as in 5b shown - in the granule intermediate container 9 contained batch of granules 4 dedusted, as based on the 2 B and 3 explained.

The dust is sucked off by the transport ejector 21 some compressed air is supplied, both supplied via the branch line 33 and the wires 26b but with a throttle 13 in the branch to the transport ejector 21 ,

The compressed air jet of the fluidizing ejector 28 is on the slanted lower part of the rear wall of the intermediate granulate container 9 directed, which is subject to heavy wear, which is why they from the outside through a metal plate 30 is reinforced.

The inclination of the rear wall in the lower area is dimensioned so that the upwardly deflected from this compressed air jet further up on the recessed in the vertical part of the rear wall sieve 5 the outlet opening 18 impinges, and this of adhering dirt, preferably adhering dust, also freed, both by directly there impinging compressed air from the fluidizing ejector 28 as well as by the entrained and against the sieve 5 spun granule particles.

Subsequently, as in 5c shown - the granule flap 6 open, eliminating the deposited granules 4 from the granulate intermediate tank 9 in the granules final container 14 falls and from there through the outlet opening 31 in the demand place.

In this process, in turn, in turn by the two compressed air nozzles 21 . 28 over the wires 26b Compressed air will be injected to during the fall of the granules 4 also to remove residues of dust from the granules again and through the dust line 20 dissipate. The flap 32 remains closed due to gravity, as a subsequent flow of air from the Granulatendbehälter 14 is possible.

Then the granule flap closes 6 again and the process according to 5a starts again.

In the pipes 26a , b are each check valves installed.

LIST OF REFERENCE NUMBERS

1

granule

2

filter

3

conveying air

4

granules

5

scree

6

granules flap

7

reservoir

8a, b

window

9

Granulate intermediate container, granules container

10

flow direction

11

dust

12

Dust collecting

13

Granule-collection area

14

Granule final container

15

delivery line

16

lance

17

Compressed air source

18

Outlet opening (air)

19a, b

level sensor

20

dust line

21

Ejector compressed air nozzle

22

control

23

pneumatic cylinder

24

axis

25

Granulate outlet

26

Compressed air line

27

cover

28

Aufwirbelungs-air nozzle

29

axis

30

metal plate

31

discharge opening

32

flap

33

manifold

34

ionized gas

35

supply body

36

Port

37

ionizer

38

Pressure-regulating valve

39

Granule inlet port

40

check valve

Claims (24)

Method for dedusting a granulate ( 4 ), the granules ( 4 ) in a granule container ( 9 ) and during ionization ionized gas ( 34 ) in the granule container ( 9 ) and at the same time the dust ( 11 ) of granules ( 4 ) is separated by the dust ( 11 ) from the granule container ( 9 ) is sucked off, characterized in that during the dedusting of the granules ( 4 ) in the granule container ( 9 ) one at the bottom of the granule container ( 9 ) existing granule opening ( 25 ) is kept closed. Method according to claim 1, characterized in that - the ionized gas ( 34 ) is introduced at a pressure above atmospheric pressure, or - the ionized gas ( 34 ) is cleaned prior to ionization of solid contaminants as well as liquid contaminants, especially oil. Method according to one of the preceding claims, characterized in that the ionized gas ( 34 ) is generated by means of an electric arc, in particular with a voltage of 2-8 kV. Method according to one of the preceding claims, characterized in that in one in a granule container ( 9 ) received granules ( 4 ) the ionized gas ( 34 ) is introduced so that it covers all areas of the granule container ( 9 ) and reaches, especially with the same volume throughput. Method according to one of the preceding claims, characterized in that the swirling of the granules ( 4 ) by injecting compressed air and the compressed air at a pressure above the injection pressure of the ionized gas ( 34 ) is introduced. Method according to one of the preceding claims, characterized in that the introduction of ionized gas ( 34 ) already when filling the granule container ( 9 ) with granules ( 4 ) or immediately after the filling of the granule container ( 9 ) with granules ( 4 ) he follows. Method according to one of the preceding claims, characterized in that - before the granules are stirred up ( 4 ) ionized gas ( 34 ) in the granule container ( 9 ), and in particular - during the entire phase of the multiple, discontinuous fluidization of the granules ( 4 ) throughout, during the whirling up and in between, ionized gas ( 34 ) in the granule container ( 9 ) is introduced. Method according to one of the preceding claims, characterized in that by means of the introduction of ionized gas ( 34 ) at the same time the granules ( 4 ) in the granule container ( 9 ), in particular by varying the pressure with which the ionized gas ( 34 ) in the granule container ( 9 ) is introduced. Method according to one of the preceding claims, characterized in that - the introduction of the ionized gas ( 34 ) in the granule container ( 9 ) via a hollow feed body ( 35 ) passing through one of the walls of the granular container ( 9 ) extends in the interior, and in particular - the supply body ( 35 ) of the contour of the granule container ( 9 ) is adjusted. Method according to one of the preceding claims, characterized in that the suction of dust ( 11 ) from the granule container ( 9 ) takes place via negative pressure, which is generated by means of compressed air and the air for generating the ionized gas ( 34 ) and / or the air for stirring up the granulate ( 4 ) in the granule container ( 9 ) from the same compressed air source ( 17 ) is taken as the compressed air to generate the negative pressure. Method according to one of the preceding claims, characterized in that - the number of revolutions of a batch of granules ( 4 ) is between 1 and 5 times, or - the period of introduction of ionized gas ( 34 ) between the resuspension processes of the granules ( 4 ) is in each case between 2 seconds and 20 seconds, in particular between 3 seconds and 10 seconds. Method according to one of the preceding claims, characterized in that the cleaning of the arc generating Ionisierspitze takes place after a specified number of operating hours. Device for dedusting a granulate, comprising - a granulate container ( 9 ), which has a granulate inlet opening for the granules ( 4 ), an outlet opening ( 18 ) for air and granule outlet ( 25 ) and is connected to a gas supply, wherein - in the gas supply an ionizer ( 37 ), characterized by - a supply body ( 35 ) for the ionized gas ( 34 ), which extends through at least one wall of the granule container ( 9 ) extends in the interior and in this inner part passage openings ( 36 ) in its wall, - wherein the hollow interior of the feed body ( 35 ) is connected to the gas supply, - the gas supply with a controller ( 22 ), the beginning and end of the introduction of ionized gas ( 34 ) in the granule container ( 9 ) controls depending on the beginning and end of a re-suspension of the granules ( 4 ) in the granule container ( 9 ) - in the operating state of the device in the lower region of the granule container ( 9 ) a granule opening ( 25 ), which can be opened and closed. Apparatus according to claim 13, characterized in that in the gas supply, a pressure control valve ( 38 ) is arranged. Device according to one of the preceding device claims, characterized in that the gas supply is a compressed air supply, in particular from the same compressed air source ( 17 ) is fed as the compressed air for stirring up the granules ( 4 ) and / or the compressed air for conveying the granules ( 4 ) in the granule container ( 9 ) into it. Device according to one of the preceding device claims, characterized in that the granulate outlet opening ( 25 ) is closable by means of a closing device and the closing device of the granulate outlet opening ( 25 ) from the controller ( 22 ), Device according to one of the preceding device claims, characterized in that the supply body ( 35 ) a round tube is with passage openings ( 36 ) in the walls of the tube and in the closed end face of the tube. Device according to one of the preceding device claims, characterized in that - the supply body ( 35 ) consists at least on its inside of an electrically non-conductive material, in particular plastic, or consists entirely of such a material. Device according to one of the preceding device claims, characterized in that - the granule container ( 9 ) has a volume of less than 2000 cm ³ , in particular of less than 1500 cm ³ , and in particular - with a batch of granules ( 4 ) filled granule containers ( 9 ) between 80 and 200 ml granules ( 4 ) contains. Device according to one of the preceding device claims, characterized in that - in the air outlet opening ( 18 ) a sieve ( 5 ) is arranged, which of dust ( 11 ), but not from the granules ( 4 ) can be penetrated and the air outlet is in particular connected to a vacuum source, or - the fluidizing fluid nozzle ( 28 ) and the transport ejector ( 21 ) by means of a simple manifold ( 33 ) are actuated from a single valve, and in the branch to the transport ejector ( 21 ) a throttle ( 13 ) is available. Device according to one of the preceding device claims, characterized in that the lower region of the granule container ( 9 ) is conically tapered with a sloping rear wall in the lower area. Device according to one of the preceding device claims, characterized in that - the whirling nozzle ( 28 ) has a plurality of nozzle openings, at least a plurality of obliquely directed upward, or - the device an operating hours counter for the ionizer ( 37 ). Device according to one of the preceding device claims, characterized in that - the granule container ( 9 ) a granular intermediate container ( 9 ) and in addition a granulate end container ( 14 ) below the granulate intermediate container ( 9 ), and in particular - the granular intermediate container ( 9 ) about a horizontal axis ( 29 ), in particular behind the granule opening ( 25 ) is arranged, opposite the granulate end container ( 14 ) is foldable. Device according to one of the preceding device claims, characterized in that the delivery line ( 15 ) for granules ( 4 ) by a closure device, eg a closure flap ( 32 ), lockable, in particular with the control ( 22 ) and is controlled by this.

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