DE2846551A1 - Pneumatic conveyor system including sifting equipment - has adjustable sieve inside coarse material hopper between top and bottom chambers - Google Patents

Abstract

The sifting equipment is for use in a pneumatic conveyor working at 0.6-0.8 bar pressure, having a collecting hopper to which a telescopic suction pipe is connected. This is followed by separators and an exhauster, grading according to grain size hot, and highly abrasive filling powder, being partic. for furnaces producing block electrodes for Al smelting electrolysis, the powder being exhausted after manufacture of the electrodes. The sleeve has an adjustable gap, and is mounted inside the coarse material hopper on an intermediate bottom dividing the hopper into top and bottom chambers. A gap in the sieve joins the two chambers to equalise the pressure, and the suction pipe ends inside the sieve. A fan is connected at the pressure side to the lower chamber, generating a sifting air current, while its suction side is connected to the upprt chamber via a separator for the fine material and a pipe. The latter is also connected to the pipe leading to the exhauster.

Description

Arrangement and design of a sifter

in a suction air conveyor system " The invention relates to the arrangement and design of a sifter in a substantially between 0.6 and 0.8 bar pressure working suction air conveyor system, consisting of a collecting container with connected telescopic suction line, nearby separators and a suction air generator for the grain-sized separation of hot, strongly abrasive ones Filling powder, as it is in particular from kilns for the production of block electrodes for the aluminum melt flow electrolysis after the electrodes have been completed will.

This electrode production is supported by LUEGER, Lexikon der Technik, Roro edition, volume 47, pages 164 to 166.

Accordingly, the pre-pressed block electrodes become yellow placed in deep furnaces, embedded in filling powder and slowly increased to 13,000 C to 14,000 C heated up and slowly cooled down again.

This process usually extends over a period of several weeks.

The filling powder is usually based on coking coal. In interest embedding with as little dust as possible and maintaining an optimal, even The granulometry of the filling powder, which enables degassing, generally requires to separate the fine dust from the reusable filling powder and this to separate grain fractions.

For this purpose, the filling powder has so far been taken from the stationary kilns sucked into a arranged on a mobile bridge crane container, and this driven to the end of the furnace hall, drained there and placed in the stationary screening plant separated into the required grain fractions This method is right on the one hand cumbersome, on the other hand, the space on the crane trolley leaves it the high operating temperature, the low negative pressure and the high sales performance not to install a screening machine directly on top of the crane system.

As a further method for separating powdery bulk materials the wind sifting is known.

This usually takes place in the low pressure range.

For this purpose, after the filling powder has been suctioned off, a deposition and Removal from the vacuum area required. With regard to those already given This is not possible in the cramped height conditions in the furnace halls.

Based on this situation, it is the object of this invention Arrangement and design of an air separator in a Sauyluft conveyor system, according to the classification mentioned at the beginning, with the one in the range of a low Satisfactory results with negative pressure, with fluctuating pressures and temperatures be achieved.

The inventive solution to this problem provides that a with sifter equipped with adjustable viewing gap cross-section within the collecting container for the coarse material on a container separating this into an upper and a lower chamber Intermediate floor, leading through this and the two chambers, via at least one formed in the sifter gap is arranged pressure-equalizing connecting, wherein the suction line ends inside the classifier, and that in addition a with dcr Lower chamber, fan connected on the pressure side to generate a stream of classifying air is provided, the suction side with the upper chamber via a; n separator for the fine material and a pipeline is connected, this connecting pipeline Furthermore, the pipeline leading to the Sauylufterzeuyer is connected.

This arrangement of a sifter directly inside the collecting container on a preferably inclined, the container into an upper and lower Chamber separating intermediate floor, allows the image of a through the sifter of view air flow leading upwards from the bottom in the area of the introduction into the The classifier is completely separated from the actual conveying air flow.

The clearing air menye and their speed in the viewing gap is thereby practically exclusively through this lesturg of the additional fan and through the setting of the passage cross-section is determined by the viewing gap.

The heavy parts of the exiting from the suction line in the classifier Material flow are deflected in this, for example on a baffle plate, and fall back into the lower chamber of the collecting container, while the finer parts pass through borne the sifting air stream, fail essentially in the upper chamber and from this - in the case of sloping ground - can be carried away due to gravity.

The additional separator provided ensures that there is an indulgence and that exiting from the upper chamber and that from the downstream separator Accruing goods can be combined or individually bunkered.

A further development provides that the subordinate separator a temperature and for the pipe connecting the fine material and the fan Pressure-sensing measuring and regulating device including a connected control device for stepless adjustment of the viewing gap cross-section via an adjusting ring is provided.

Servomotors are usually provided as the control device, which are connected to the preferably conical adjusting ring.

Since, as already mentioned, the one from the upper chamber of the collecting container and brought together from the first downstream separator for the fine material can be, it is provided that in the classifying air circuit between the classifier and Separator an additional settling tank is arranged.

Since the separation of the coarse fractions is highly abrasive, it is intended that that a replaceable baffle plate for their separation from the conveying air flow is intended as part of the sifter.

In summary, it should be noted that the intended arrangement and Training of a classifier in a suction air conveyor system in the full scope of the task is fair.

The sifter can, however, practically independently of the suction air Consideration of the given pressure and temperature conditions on a optimal classifier performance can be set.

The arrangement and training according to the invention is illustrated by the attached Drawings explained in more detail in an exemplary representation.

Figure 1 shows the flow diagram of a filling powder suction and sifting system, how it can be arranged on a bridge crane.

Figure 2 shows the classifier in section.

The filling powder system shown in Figure 1 consists of a telescopic Suction pipe 1, which opens into the classifier 2 and here through the distributor plate 18 is limited.

The classifier 2 is in the coarse material collecting container equipped with a gate valve 4 3 arranged on an inclined intermediate floor 33, namely passing through this. The admixing floor 33 divides the collecting container 3 into an upper chamber 31 and one lower chamber 32. The upper chamber 31 is equipped with the gate valve 6 Settling tank 5 connected, which in turn again the separator 7 for the fine material is connected via the gate valve 8.

The classifying air circuit leads from the fan 11 into the lower chamber 32 of the collecting container 3, from there over the classifier 2 and viewing gap cross-section 21 into the upper chamber 31, into the collecting container 5 and here via lines 9, the are connected to the separator 7 via the measuring and control device 10 back to the fan 11.

The pipe 9 is also connected to the suction air generator 16 leading pipeline 12 connected.

In the pipeline 12 there is also a dust separator 13 arranged with a coupled by gate valve 15 dust collector 14.

The design of the classifier 2 is explained in more detail by FIG.

In this center there is an impact separator to the outlet of the suction pipe 17 arranged. The material diverted here is transferred to the outlet of the suction pipe 1 connected distributor plate returned to the lower chamber 32.

In the upper area is the conical viewing gap adjustment ring 19 arranged, which is set by the servomotors 20 in toner position.

Claims (4)

Claims arrangement and design of a classifier in one A suction air conveyor system operating essentially between 0.6 and 0.8 bar pressure, consisting of a collecting container with a connected telescopic suction line, downstream separators and a suction air generator, for grain-sized separation of hot, highly abrasive filling powder, such as is used in particular from kilns Manufacture of block electrodes for aluminum fused flow electrolysis after completion of the electrodes is suctioned off, characterized in that a with adjustable Viewing gap cross-section (21) of equipped sifter (2) within the collecting container (3) - for the coarse material on this container (3) in an upper (31) and a lower Chamber (32) separating intermediate floor (33) leading through this and the two chambers (31 and 32) compensate for pressure via at least one gap (22) formed in the classifier is arranged in a connecting manner, the suction line ending inside the sifter (2), and d a ß additionally one with the lower chamber (32) on the pressure side connected fan (11) is provided for generating a stream of classifying air, the suction side with the upper chamber (31) via a separator (7) for the fine material and a pipe (9) is connected, this connecting pipe (9) also connected to the pipeline (12) leading to the suction air generator (16) is. 2. Arrangement and training according to claim 1, characterized in that d a 13 in the downstream separator (7) for the fine material and the fan connecting pipe (9) a temperature and pressure detecting measuring and control device (10) including a connected control device (20) for stepless adjustment the viewing gap cross-section (21) is provided via an adjusting ring (19). 3. Arrangement and training according to claim 1 and 2, characterized in that d a ß an additional one in the classifying air circuit between the classifier (2) and separator (7) Settling tank (5) is arranged. 4. Arrangement and training according to claim 1 to 3, characterized in that d a ß an exchangeable baffle plate for their separation from the conveying air flow (17) is provided as part of the classifier (2).