DE2609509A1 - Dust removing arrangement for flat grain driers - has porous filter hoses or endless filter belt for rejected air - Google Patents

Abstract

The dust removal arrangement is used in the flat drier for example for drying grain, by a heated air stream, and exposed at the end of drying process to a cooling air flow. The waste air is cleaned to a high degree from dust, and the system operates with low pressure drop. The whole drier is enclosed in a chamber (2). The drying gas and the cooling air is supplied from the atmosphere outside the enclosure. The waste air is rejected into atmosphere through an opening at the top through a porous separation wall. The outlet opening is connected to the extraction chamber made from porous material which forms a dust collector on its underside. Filter hoses (9) are arranged to form the air extraction chamber. An endless filter belt which can be drawn over the waste air outlet openings is cleaned from adhering dust in a dust collector chamber.

Description

Dipl-lng. Rudolf Seibert Legal approach ■ Patent attorney KA H. PA Dipl.-Inp. Stltwrt, I MOncScn 22, St * intdorfsfra6 · i

MUNICH 22, Steinsdorfstrasse 6 Telephone (089) 29 34 U Postal checking account: Munich 1 * 3515-80) Bank account: Bayer. Association bank 900

Wh _S .:

leonhard-Frank-Strasse 3 Telephone (089) 3 00 67 M

Attorney File 3079

& fe 1076

Stefan Laxhuber KG, 8332 Massing

Dedusting device for flat dryers

The present invention relates to a dust collector for flat dryers, in particular for so-called push-and-turn dryers. With these types of dryers, this will be the case Goods to be dried, e.g. crops such as cereals or the like, a warm gas flow, preferably a warm air flow.

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sets and, if necessary, a flow of cooling air at the end of the drying process. It is the peculiarity of the one to be dried It is good that a relatively large amount of dust, e.g. stalks and the like. between the actual good is present, which is the permanent Turn is whirled up by the air passing through and is also removed with the air flow.

It is known to separate this dust again with the aid of cyclones, the cyclones themselves not only being proportionate are expensive, but the operation of the same requires a relatively high expenditure of energy to reduce the pressure loss To compensate for drying air, which is about 50 to 80 mm water column. A simple separation in dust chambers is in most cases not sufficient.

By using cyclones, however, the operating costs of a simple dryer are significantly increased and thereby reduces profitability.

The object of the invention is to create a dedusting device for flat dryers that has a high degree of cleaning the exhaust air is guaranteed, has a simple structure and only a small pressure loss has to be accepted, what in turn enables a lower inlet pressure during the drying process.

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This task is carried out with the dedusting device for flat dryers solved according to the invention in that the entire dryer is housed in a closed room »or itself has a cladding that the drying gas and optionally the cooling air are fed to the dryer from the outside and that the exhaust air from the room or the cladding through a preferably in the ceiling of the room or the cladding provided exhaust opening is in turn passed to the outside via a porous partition.

In the dedusting device for flat dryers according to the invention, an air cycle is carried out from the outside in such a way that that the drying air is let in from the outside and the dusty air that flows through the goods to be dried has, in turn, led to the outside via a filter layer will.

The implementation possibilities of such a dedusting device are based on the following description in conjunction with the drawing, in which two design options are reproduced, explained. Here the

Fig. 1 is a schematic sectional view of an overall layer, consisting of flat dryer with dedusting part according to the Invention,

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Fig. 2 shows an enlarged partial section of the filter chambers and

Fig. 3 shows another embodiment of the invention with a
Filter belt.

In Fig. 1, a so-called push-and-turn dryer is shown schematically in section and designated across the board with the reference symbol I ^. This dryer has a sieve-like shape on the underside
openings through which the air heater 4 is heated
Dry air passes through the property. The goods run along with this
Help the longitudinally movable push and turn device 5 from left to right. At the end of the drying process, cooling air is blown through the material via a fan (not shown), and when
Removal of the goods to get no significant temperature differences to the ambient temperature.

According to the prerequisite, the entire Trocjner I ^ i * ^{1 is} housed in a closed room 2 or has its own cladding, the fan 4 for the warm air, as well as the fan for the cooling air sucks in the air from the outside and in the room or the cladding through the Pushes well.

The outlet opening is on the top of the room 2 or the cladding 3 provided through which the exhaust air, which carries large amounts of dust with it, exits. At this exhaust opening

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an air shaft 6 is connected, which leads the dusty and moist, warm air to the air distributor 7. This air distributor has on its underside a plurality of openings with fastening stubs 8 through which the exhaust air in Filter hoses 0 overflows.

The filter bags themselves are made of a porous material, preferably made of a correspondingly coarse fabric made of textile or metal threads. In the context of the invention, the Filter bags, however, also made of other porous material, for example a sieve-like one with correspondingly fine openings provided sheet metal.

The exhaust air passes through the pores or meshes and leaves behind the dust inside the filter bags is emitted via the vent 10 as pure exhaust air.

Dust collectors 11 are located at the lower end of the filter hoses 9 provided, which are connected to the filter hoses 9 in an airtight manner via fastening nozzles 12.

The dust collectors themselves have one or more connections 13 for attaching dust bags 14 to during operation to replace the bags 14 filled with dust with empty ones

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can be used without air and dust escaping are gate valves 15 provided.

When dimensioning the overall system, according to a further proposal of the invention, the filter surface should be selected in this way that only a slight overpressure (less than 10 mm water column) builds up inside the dryer room. With one like that At low pressure, the room can then be entered at any time via a tightly closing door without the need for special pressure locks etc. would have to be provided.

2 shows a section on a correspondingly larger scale of Fig. 1 along the dashed line II-II, wherein the exhaust port 10 is omitted. In FIG. 2, the parts corresponding to FIG. 1 are provided with the same reference numerals as in FIG. 1.

The operation of the dedusting device is described below with reference to FIG explained according to the invention.

The dust-laden air enters the filter hoses 9 at a relatively high speed v1 through the fastening stubs 8. Appropriate dimensioning ensures that the free

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Filter area A2 is a multiple of the inlet cross section A1. The sudden increase in available for air discharge free filter surface causes the exit velocity of the air v2, which is perpendicular to the filter surface, thus acts in relation to the longitudinal extension of the filter bags 9 A1 decreases to A 2. However, the dust particles in the air itself move practically with speed v1 to the dust collector 11 without affecting the speed v2 exiting air to be significantly influenced. A coating of the filter wall with dust occurs with correct dimensioning the areas A1 and A2 as well as the correct choice of the number of filter bags does not appear.

Since the warm exhaust air leaving the dryer is usually a has a relative humidity of 60 to 80%, there is a risk of water vapor condensation, especially in the cold season on the filter surface. This would lead to clogging of the filter surface. The falling below the dew point can be prevented by installing the entire filter hose assembly in a filter housing (not shown) or by using it a special filter chamber can be bypassed.

FIG. 3 shows in cut another Realisierungsmög-

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possibility of dedusting the from the receiving the dryer Room exiting air according to the invention. In FIG. 3, only the passage opening 3 of a space 2 is enlarged Scale reproduced. The room 2 itself corresponds essentially to the room 2 in Fig. 1 and is used for recording a flat dryer according to the proposal according to the invention. Through this opening 3 leaves the humid and dust-laden Air the dryer room. At this opening is a Filter belt 16 is provided which, as will be described below, cleans the exhaust air before it can enter the atmosphere. For this are in a flat sheet steel housing 17 two rubber-coated Rolls 18 and 19 are provided, over which the filter belt 16 as ei.n endless metal or textile fabric tape is performed. In addition, a brush roller 20 is located in the housing 17. The rollers 19 and 20 are driven by a gear motor 21 in the direction of the arrow. A tensioning device is located on the roller 18 22, which keeps the filter belt under tension, so that proper friction between the rubber roller 19 and the filter belt 16 is guaranteed.

The dust particles in the exhaust air attach themselves to the filter belt due to the flow velocity and are carried through the same in the direction of the arrow to the dust collector 23, which corresponds in its function to the dust collector 11 in FIG. 1, transported.

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Since there is no air flow in the area of the dust collector, the dust particles are relatively easy to detach from the filter belt and fall into this dust bag collector and finally into the dust bag 24. The remainder, possibly still on the filter belt Firmly adhering dust particles are wiped off by means of the slowly rotating brush roller 20. Incidentally, the The dust collector, the sack connection piece and the dust sack itself are designed in accordance with the embodiment according to FIG. be provided, for example, with a gate valve, etc.

The dedusting device for flat dryers according to the invention was made relatively based on two specific exemplary embodiments explained schematically. Here, constructive individual parts have only been dealt with as far as they are necessary for understanding of the invention are of importance. Of course, the dust collector and the filter bags are in training A large number of modifications are possible in the arrangement and guidance of the filter belt, all of which reflect the basic idea of the invention can realize. In any case, care must be taken that the exhaust air comes out via a correspondingly coarse-meshed fabric Textiles or metal or glass, etc. is removed, whereby it must be ensured that the fabric itself is attached Dust particles either through suitable air ducting or through

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Transport of the tissue in an area in which there is no overpressure, however slight, is made possible.

-Patent claims-

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Le

first page

Claims (7)

Claims 1. | Dedusting device for flat dryers (push-and-turn dryers), in which the dried goods, e.g. crops, are fed into a warm gas stream, preferably a warm air flow and optionally a cooling air flow at the end of the drying process, characterized in that that the entire dryer (1) is housed in a closed space (2) or a panel possesses that the drying gas and optionally the cooling air from the atmosphere outside the closed The room and that the exhaust air from the room or the cladding via a preferably in the ceiling the opening (3) located in the room or the cladding (cover of the dryer) via a porous partition wall is led to the outside. 2. Entstaubungsexnrxchtung according to claim 1, characterized in that the exhaust air opening provided in the ceiling (cover) of the room or cladding is connected to at least one air extraction chamber made of porous material (4) which merges downward into a dust collection basin. 709838/0039 -12- -H- 3. Dedusting device according to claim 2, characterized in that that filter tubes (9) are provided as the air extraction chamber »ι 4. Dedusting device according to claim 1 to 3, characterized due to the parallel arrangement of several air extraction chambers (filter hoses) (9) for cleaning the exhaust air. 5. Dedusting device according to claim 1, characterized in that that in the exhaust duct, preferably directly over the exhaust opening one to an infinite band closed filter belt or porous film (16) is arranged, which pulled past the opening and over a dust collection space is freed from attached dust. 6. Dedusting device according to claim 5, characterized in that that a stripping roller (20) is provided, which on the tape or the film (16) adhering dust when Passing a pulley in, stripping a dust collector. 7. Dedusting device according to one of the preceding claims, characterized in that the individual dust ; ι ι 709838/0039 -13- collection rooms preferably with the interposition of a gate valve into exchangeable dust collecting containers, e.g. bags (14,24), in which the accumulated dust due to gravity falls. 709838/0039