DE2332986A1 - PROCESS FOR CLEANING A STREAM OF MECHANICAL CRUSHED MATERIAL AND EQUIPMENT FOR CARRYING OUT THE PROCESS - Google Patents

Description

Dr. Pichard Glawe
Dipl-lng. Klaus Delfs

Patent attorneys

United Austrian Iron
and steel works - Alpine Montan
Corporation
in Vienna

Method of cleaning a stream from mechanical
crushed material and equipment for carrying out the process

The invention relates to a method for cleaning a stream of mechanically comminuted material / such as wood chips, which are primarily used for the production of
Cellulose, cardboard or fibreboard are intended.

During the production of cellulose, cardboard or Paser boards, impurities such as sand, stones,
Metal parts or the like, which with the raw material
be carried along, cause operational disruptions or
even cause a standstill.

Various methods and devices have therefore been used to clean the raw material added to the process.

3098ÖA / 0A97

leads is developed. The raw material was either washed with liquids or on mechanical route by dry sorting, such as sieving or shaking, if necessary with the aid of a Air flow, treated.

■ In many cases, washing has reduced the level of impurities be greatly diminished; but the large amounts of liquid that must be used and in Introducing the following manufacturing process involves operational difficulties. Washing systems with sufficient capacity for the entire flow of raw materials are also expensive and take up a lot of space.

In mechanical cleaning processes, the separation of foreign particles is rarely complete. Sometimes it can a good separation of particles of a certain type can be achieved, while in other cases only an enrichment can be achieved by particles in a part of the material.

The aim of the invention is to avoid the disadvantages of the known cleaning methods and to make it possible. Bringing material, in particular wood chips and sawdust, to a low level of impurities, without adding large amounts of liquid to the material.

The inventive method with which this goal is achieved is that, in a subsequent second stage, the material flow is pneumatically blown with Controlled pressure air is diverted and sorted, with heavier particles falling through the air stream and thereby be separated.

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An advantageous device for performing this method comprises a sieve apparatus with one to one Sieve inclined towards the central outlet. It is characterized in that below the outlet of the sieve a distribution cone and a collecting funnel arranged at a distance below it is provided, the outer one The edge of the edge of the distribution cone protrudes, whereby an annular gap is formed, a pneumatic blow molding: direction is arranged outside the gap and a

ring-shaped baffle surrounding the edge of the distribution cone is provided for deflecting the material flow.

The collecting funnel and the blowing device are advantageously arranged coaxially to the outlet.

The method according to the invention and the device for carrying it out are explained in more detail in the drawing, which shows a schematic vertical section. The arrow Ä indicates the incoming material flow that is to be cleaned and sorted. Arrow B indicates the stream of purified material flowing out of the facility. The arrows C .. and C ₂ denote outflowing material flows in which impurities from the main flow are accumulated.

In the vibrating sieve 1, material A flows from the inlet Via a distribution hump 5 on a distribution plate This distribution plate 7 is at its .Peripherie of a Shell 9 surrounded, in the bottom of which the actual sieve 11 for the passage of a certain particle size of the main stream is accommodated. Under this sieve 11 is located A collecting bowl 13 with an outlet 15 is located. The sieve 11 is slightly inclined in the direction of a central outlet 17.

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According to the invention, a distribution cone 19 is located directly under this outlet 17 and at a certain distance including a collecting funnel 21, the periphery of which does not extend beyond the distribution cone 19 and with this one annular gap 23 forms. A pneumatic blowing device 25 is arranged in a ring outside the gap 23, to blow a stream of air through the gap towards the center. Located outside the distribution cone a guide plate 27, the lower edge of which is arranged somewhat inside and above the blower device 25.

The device works in the following way: The material flow A, consisting essentially of wood chips, is applied via the distribution hump 5 and the distribution plate 7 in the form of a relatively thin layer along the outer circumference of the sieve 11, from where the material as a result of the shaking movement of the sieve 11 and the inclination of the sieve 11 against the outlet 17 migrates. The sieve 11 lets through essentially small and heavy particles, such as sawdust, sand and grit, which collect in the collecting bowl 13 and flow towards the outlet 15 as material flow C-. This stream of material C. can either be washed or discarded. The material that does not fall through the sieve 11 migrates towards the outlet 17 on to the distribution cone 19, from the lower edge of which it emerges as a thin layer against the air flow coming from the blower ring 25. The guide plate 27 prevents material from the distribution cone 19 from reaching outside the effective area of the blower device 25. The air flow from the blower device 25 is adjusted so that it allows relatively heavy particles of the raw material and the impurities to fall through, which are collected _{as material flow C 2.} Stream C ₂ is subsequently washed or discarded. The particles of the raw material of normal nature are carried by the air flow

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passed the gap 23 into the collecting funnel 21, the bent edge of the guide plate 27 as Diverting organ acts. The blown air is either through an air vent or an air duct on Distribution cone 19 or discharged through the collecting funnel 21. The cleaned material is discharged as stream B from the collecting funnel.

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Claims (3)

Patent claims: experienced in cleaning a stream of mechanically crushed material, such as wood chips, the primarily intended for the production of cellulose, cardboard or fiberboard, by mechanical means Sorting and, if necessary, washing, the flow of material being passed through a vibrating sieve is freed from heavier particles of smaller diameter, characterized in that in a subsequent second stage of the material flow pneumatically by blowing air at regulated pressure is diverted and sorted, with heavier particles falling through the air stream and being separated off as a result. 2. Device for performing the method according to claim 1 with a central outlet inclined sieve, characterized in that below the outlet (17) of the sieve a distribution cone (19) and a collecting funnel arranged at a distance below (21) is provided, the outer edge of which is protruded by the edge of the distribution cone, with an annular gap (23) is formed, a pneumatic blowing device (25) is arranged outside the gap (23) and an annular The guide plate (27) surrounding the edge of the distribution cone (19) is provided for deflecting the material flow is. 3. Device according to claim 2, characterized in that the collecting funnel (21) and the blowing device (25) are arranged coaxially to the outlet (17). 309884/0497