DE2021881A1 - Method and device for the continuous mixing of granular materials - Google Patents

Description

Dr. ing. E. B ERKE N FELD · 'Dip I, -1 ng. H. BERKENFELD, patent attorneys / Cologne Attachment file number - ^ -

for entry of April 27th . ' 1-970 Sch // "Name d \ Note Ma» Le Va

Method and apparatus for the continuous mixing of granular materials.

The invention relates to a method and an apparatus for continuous mixing of granular materials which have the same or different density or particle size. The invention represents an improvement against-; | above the batch process described in British Patent 94j5,085. As in the lot procedure stop stirring and ventilate the container after each Mixing process must be emptied, is between the introduction of a batch and the introduction of the next batch consumes considerable time.

Another disadvantage is that the capital investment per unit weight of the material to be mixed is considerable and the results that can be obtained are inferior than would be desirable.

Most of the commonly used mixers rework the principle of a tumbling drum. 'When the differences in density or particle size are substantial but will not be homogeneous mixtures achieved. In such cases, the tumbling causes a separation of the materials by concentrating the heavier particles of the bed near the bottom of the bed.

It is therefore an object of the invention to provide training a new method and a device for the continuous aerated mixing of granular material, to achieve substantial labor savings.

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a.

Another object of the invention is to provide a novel method and apparatus which have a require less capital investment and lower operating costs than the batch process.

Another object of the invention is to provide a novel method and apparatus for continuous Mixing of granular materials, so that overall better repeatability of the mixing results, in particular a better uniformity of the mixed materials can be achieved is.

Yet another object of the invention is to provide an improved apparatus which can be used for a given Floor space has a much greater capacity.

Another object of the invention, compared to the above-mentioned wobble principle and the lot method, is that the make individual mixtures more homogeneous by keeping the heavier or larger particles in place in the batch while careful mechanical agitation and just adequate ventilation come into play so that leash Segregation occurs.

The invention therefore relates to a method and an apparatus for the continuous mixing of granular materials, which have the same or different density or particle size. The device consists of one or more containers, which are beveled downwards and inwards. Each container is equipped with a stirrer that rotates around a vertical axis is rotatable to stir the granular material at the same time that air is passed through it. Two or more stages can be arranged in series, either side by side or in a vertical direction one above the other, with the solid substances can be conveyed pneumatically or by gravity between these stages «,

Further features and advantages emerge from the following. Description with reference to the drawings, in which L 65/2 '_2-

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shows:

Fig. 1 in elevation, partly in longitudinal section, a single-stage Apparatus constructed in accordance with the principles of the invention,

Fig. 2 is a schematic view of a two-stage device according to the invention, in which mixed particles and air to the top of the second stage be funded,

Fig. 3 shows a two-stage device in which mixed Particles and air from the first stage are pneumatically conveyed to the lower end of the second stage,

Fig. 4 shows a two-stage device, the units in perpendicular direction are arranged one above the other.

Figures 5 and 6 show a two-stage device whose Units as in Fig. 4, one above the other in a vertical direction are arranged, but which has various modifications.

Fig. 7 shows a modified embodiment of Fig. 1,

8 'shows a partial side view of another embodiment of the connection in a two-stage process direction,

Figure 9 is a partial side view of yet another embodiment the connection in a fluidization device,

Fig. 10 is a partial side view of a further embodiment the connection in a fluidizing device and

Figure 11 is a partial side view of yet another Embodiment of the connection in a fluidizing device.

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In Pig. 1 is denoted by 1 a container, which is essentially has the shape of a cone. The container is provided with a vertical shaft 6 which rotates around its axis and which by means of a frame 6a supports a plurality of blades or agitators 6b, which are around and along the entire height the shaft are arranged to intimately mix the granular materials of the same different density or particle size, which are introduced through the inlet tube 2 for the solids. Low pressure air is introduced into the air inlet pipe 4, goes through the entire height of the mixture and exits through the outlet pipe 5. The device described so far is similar to the lot device described in British Patent 9 ^ 3 085 except that the known The device has no inlet and outlet openings for the solids, while the present device has both with an inlet opening as well as with an outlet opening is provided for the solid substances. In addition, the outlet port of the present device is about 1/3 to 1/4 of the height L of the solids arranged. In addition, a synchronization of the inlet valve 2 'and the outlet valve 7 for the fixed Substances provided, which is an absolutely necessary requirement for continuous mixing.

A sieve or a porous plate 8 is provided in order to prevent solid substances from penetrating into the tube 4 during an interruption in operation. The solids are therefore simultaneously agitated while air is passed through them and then discharged through pipe 5, either into the atmosphere or into a cyclone, to recover entrained particles. The container 1 can be ^{completely emptied through the outlet valve 7 1} and the pipe 3 ¹ as soon as this is desired, for example when new mixtures are to be mixed.

The essential feature of the operation of the device according to FIG. 1 is that the speed of removal of the solids through pipe J5 and valve 7 at speed the introduction of the solids through the inlet pipe 2 must be synchronized. Eie £ t such synchronization can be achieved in several ways. Mechanically, the-L 65/2 _4_

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the same can be effected in that the opening of the outlet valve 7 is closed

is set until the discharge speed is such that the level L is kept at a constant level during the entire process of continuous introduction of the solids through the inlet pipe 2. Perhaps the most suitable method of synchronization is to determine the differential pressure Λ P of the air passing through the device, which is proportional to L. Since the differential pressure depends on the mass of the solids into which the air must penetrate as it moves upwards, any change in the level L of the solids will affect the differential pressure.

However, the level L of the solids will only change if the rate of introduction is not equal to the rate of discharge. Accordingly, any known level control device can be used to operate the valve 2 'in response to changes in the level L so that the opening of the valve is changed to the extent necessary to keep the level L substantially constant. The most common type of mechanical device that can be used for such level control may be similar to a float operated valve such as is commonly used in water closets for toilets. Namely, when the float located at the level L is moved in the vertical direction, the same through a mechanical linkage the opening is modified, the Λ exhaust valve 7 cause the same only to a sufficient extent, the opening or closure in order to keep the level L at a constant level . Yet another method is to cause selected contacts to be closed by a part whose position is monitored by level L so that a relay or motor is actuated which in turn actuates valve 2 * to do the same in accordance with changes in level to be regulated so that the level is kept essentially constant.

A typical control device is in Pig. 1 shown. the Electrodes D are adjustable in the vertical direction, so that the same set according to the desired differential pressure Δ P

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can be provided. When the level L drops below the desired level, an excitation circuit can be closed via the battery B and the relay A in order ^{to actuate the inlet valve 2 1} and to open the same to a greater extent, while the valve 7 is partially closed. In this way, the. Inlet and outlet flow of solids synchronized to maintain the desired level L of solids. If the differential pressure ΔΡ becomes too large, the flow through the inlet valve 2 * is reduced, while the outlet valve 7 is opened to a greater extent. In a modified embodiment, each valve can be operated alone in the manner described.

Fig. 7 shows a modified embodiment of Pig. 1 with a lower cylindrical section which has a diameter d which is not greater than half the diameter D of the container and the height L ^{MI of which is} not greater than 1/3 of the height L ^: . L ¹ \ denotes the height that extends below the bottom of the cylindrical section.

2 shows, as a modified embodiment, a two-stage device into which the materials to be mixed enter through the inlet pipe 2, while low-pressure air enters the first stage through the inlet pipe 4. The cleaning outlet J5 ^f is also connected to the pneumatic conveying line 4 for cleaning and emptying purposes. The important transmission line for the solids is again the line 5. The flow control valve 7 for the solids is synchronized with the inlet flow through the pipe 2 by one of the methods described above. The mixed particles and air are pneumatically conveyed through the pipe 10 by introducing low pressure air at one end so that the partially mixed solids are pneumatically conveyed into the upper end of the second stage and discharged through the pipe 11 so that they onto the Top of the indicated level of solids fall. Air is introduced into the lower end of the second stage through the inlet pipe 4a, and the solids control valve 7a is synchronized with the solids feed rate in order to divert the solids through the

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Drain outlet pipe 9. Air can pass through the upper outlet pipe 5a exit into the atmosphere or into a cyclone 24. By operating the valves A and B, the cyclone 24 can be used be det or not. The cyclone may be necessary for very fine particles.

FIG. 3 shows a modified embodiment of the two-stage device according to FIG. 2. The solids are not fed to the upper end of the second stage after mixing in the first stage, but rather directly into the lower end of the second stage through the pipe 10b pneumatically conveyed into which air is introduced at one end. This air not only causes the movement of the mixture mini-pipe 10b9i but at the same time fluidizes the charge in the second stage in the container 1b. on the right side of * Fig. 3. In order to improve the mode of operation, the air inlet pipe 1 should be widened somewhat and covered by a guide wall 12 in order to prevent solid substances from falling back into the pipe 10b during an interruption in operation. Instead of the guide wall 12, a pipe which is bent at an angle of 90-180 ° can be attached to the upper mouth part of the pipe 13. Since the conveying air conveys the solids from the first stage to the second stage, the speed of the air when entering the second stage is lower and the conveyed solids are deposited as a bed. For proper operation of such a device, the air velocity through the pipe 10b must be defined similar to that coordinated carefully required for aerating the batch in the second stage. In some cases it may be necessary. Supply secondary air through pipe 15 or 16.

The two-stage device shown in Figures 2 or 3 is particularly suitable for those cases in which carefully prepared mixtures are needed and in which the solid Substances have sufficiently good flow properties to enable the pneumatic transmission shown. Desired- ■ if necessary, 2 or 3 additional stages can be added to the figures when more even mixes are required.

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When the solids are introduced into the second stage through the pipe 10b, the bed is formed in the second stage and stirred. If the level of the bed is that indicated in FIG. Solids level is reached, the mixed solids will overflow and through the adjustable valve 1j5 and the Pass outlet pipe 14 through.

Fig. 4 shows a two-stage device, in which, however the steps instead of side by side as in Figures 2 and 5 in perpendicular direction are arranged one above the other. This arrangement has the advantage that only one agitator motor is used for both stages and a reduction gear are required, since both agitators for stages 1 and 2 are arranged on a common shaft are. There is a sealing arrangement for the agitator shaft at the transition from the upper or first stage to the lower or second stage provided so that stuffing boxes and the like are unnecessary. To form such a seal, that can Bed of the gestures fabrics themselves can be used as below is described.

In operation, the solids to be mixed enter the first stage through the inlet pipe 2 to form the level L shown. The solid substances are retained in the first stage, ie in the container 1, since the valve 24 is closed and no substantial amount of the solid substances can fall through the bearing sleeve 21 which is inserted into the end flange 20. and through which the agitator shaft 6-6c passes. Air is introduced through valve 17 while valve 18 remains closed and the batch is agitated. As soon as sufficient stirring and simultaneous aeration have taken place in order to produce a homogeneous mixture, the valve 24 is opened so that the now partially mixed solids are fed into the lower container 1c, ie. can overflow into the second stage. Air is before the level L is reached · _{2 t} admitted through the inlet pipe 4c and through the porous plate 8ö, while the mixers are already in operation mix the solids uniformly. As soon as the level L _{2 is} reached, the control valve 7c is actuated and the mixed solids are discharged through the outlet pipe j5c. Those from the second stage from-L 65/2 “ ₈ .

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Exiting air can either be passed through the valve 18 in order to support the ventilation of the first stage or it can passed through tube 19 to the top of the first stage and discharged through the pipe 3 into the atmosphere or into a cyclone will.

Pig. FIG. 5 shows a modified embodiment similar to FIG. Instead of the final flange 20 at the lower end T5d of the first Step an ^ adjustable trough 22 is provided, the outside the sleeve 23 is formed and in the vertical direction around a distance χ can be set to match the opening and the Removal speed from the first to the second stage change. Low pressure air is introduced into the tubes 17d and 18d, each of which has a valve, as well as into the tube 4.

Pig. Figure 6 shows the Pig's adjustable valve in greater detail. 5, which · consists of the trough 25 formed around the sleeve 26, -which can be adjusted by means of the bolts 27 by a distance χ in the vertical direction. By admitting air through either valve 18e or 17e, the density of the column of solids can be controlled so that, for a given space between the cylindrical portion 15e and the bottom of the trough 25, the solids usually flow from the first to the Second stage overflow, as indicated by dots. The solid substances in the trough 25 therefore form a seal between the steps . "" .- ■ '';. ; _; ^: - ■ ";...

The flow of solids through the intermediate space χ can easily be regulated even more simply by leaving either the valve 18e or 17e or both in the open position and by regulating the vertical position of the trough 25 by means of the bolts 27 or some other mechanical device, so that the flow rate of the solids through the space χ is exactly the same as the feed rate in the first stage. Air is discharged from the top of the container / Ie through the air outlet pipe 19e into the atmosphere or into one.

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Of course, the mixed solids that result from the lower end of the devices shown in FIGS are discharged with steps arranged one above the other in the vertical direction, if desired into the upper end of a Identical, two-stage device are introduced to two-stage (or multi-stage) devices arranged one behind the other to form which are similar to the devices shown in Figures 2 or 3.

Fig. 8 illustrates another connection in a series arrangement, in which a perforated plate 28 is provided at the base of the conical container. The plate 28 is with a Nozzle 28a provided for the flow of solids. The air entering the air inlet pipe 4 passes through the perforated one Plate 28 into the charge in the conical container and the aerated solids pass through the nozzle 28a into the tube J5 and into the second stage. In FIG. 8, the air entry into the second stage was improved by arranging a conical flow nozzle 1 ^ a behind the valve 7.

Fig. 9 shows a vertical baffle 29 at the junction of the air inlet pipe 4 and the outlet pipe 3 are arranged is. In this case, the air from the inlet pipe 4 is directed vertically upwards into the interior of the conical container and can therefore do not get into the outlet pipe 3.

The embodiment shown in Fig. 10 is the air inlet in the first stage through a connected to the inlet pipe 4 inverted Knee 30 forward. The solids from the first stage can do not enter the knee and the air leaving the knee supports the flow of solids through the pipe 3 into the pipe 10b to be conveyed to the second stage.

Fig. 11 provides in a similar manner an air inlet tube 4, which in place of the inverted knee of FIG. 10 with a perforated 31 is provided.

According to the invention are thus a novel method and a .Device for continuous mixing of granular materials

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provided in one "or two stages, which are either arranged in series next to each other, the solid substances being pneumatic be promoted from level to level, or vertically are arranged one above the other, the solid substances being stirred and aerated at the same time, and pneumatically after mixing be promoted from one level to the next * In addition, is a new type of sealing arrangement for vertically stacked Steps provided in the form of a thick bed, which acts as a cloth can for the agitator *.

The invention is not limited to those shown and described

example embodiments that limit the various

Changes can be made without the scope of the invention leaving.

Claims

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Claims (1)

Dr. Ing. E. BERKENFELD · D ι ρ I-1 η g. H. B E RKE N F E LD, patent attorneys, Cologne Attachment file number for entry from April 27, 1970 Sch // Name d. Note JVYes _x Lg _va Claims nigen materials, characterized by a container (1) with a vertical shaft (6) ', "to which an agitator (6b) for stirring the mixed granular materials is attached, through an inlet pipe (2) for the granular material at the upper end of the Container, through an inlet pipe (4) for low pressure air at the lower end of the container, through an air outlet pipe (3) at the lower end of the container, through an air outlet pipe (5) at the upper end of the container and through a valve (7 ') in one ^{the outlet pipe (3 1} ) * adjacent to the bottom of the container, which regulates the discharge speed of the mixed materials through the outlet pipe. 2. Device according to claim 1, characterized in that that the nut tube (3) about 1/2 to 1/4 of the height of the material is arranged. j5. Device according to claim 1, characterized in that a sieve (8) is arranged in the inlet pipe (4), which prevents solid substances from penetrating into the inlet pipe during an interruption in operation, and that the valve (7 ¹ ) regulates the discharge speed of the mixed solid substances in this way regulates that the same is the rate of introduction of the solids at the top of the container (1) substantially the same. L 65/2 -12- 109809/1269 2027881 4. Apparatus according to claim 1, characterized in that that the container in its main part as an inverted cone and is shaped as a cylinder in its lower part. ' 5. Multi-stage continuous mixing device for granular materials, characterized by a first container (1) with an agitator and an aeration device for simultaneous stirring and aeration of the granular materials in the upper end of the container are introduced through a second container (1a), which is also equipped with an agitator and a Ventilation device is provided to the contents of the same to stir and ventilate at the same time, as well as through a to the Bottom of the first container adjoining outlet pipe, which into the the second container opens and is connected to 'an air source, i to get the mixed solids and air from the bottom of the first To convey the container through the Äuslaßrohr pneumatically into the second container. 6. Multi-stage device according to claim 5, characterized in that that the outlet pipe (10) for pneumatically conveying the mixed particles with the upper end of the second container (1a) that an air inlet valve brings low pressure air into the bottom of the second container and that an outlet valve Exhausts air from the top of the second container, 7. Multi-stage device according to claim 5, characterized in that f indicates that the outlet pipe (10b) for the pneumatic conveyance of the mixed particles from the first container (1) with the lower end of the second container (1a) is connected and that means in the second container granulates the accumulation Prevents material in the outlet of the pipe. 8. Apparatus according to Claim 7 * characterized by a Outlet pipe (14) and a control valve (tj5) in the same, which is upper end, e of the second container ^ Ta) is arranged to the To regulate level of mixed granular materials in the same. L 65/2 -13- 10 98 09 / 126Ö 9. Apparatus according to claim 5, characterized in that that the first and second containers (1,1c) are arranged vertically one above the other and have a common agitator shaft (6,6c). . ■. 10. The device according to claim 9 $, characterized in that a seal is provided at the bottom and at the discharge end of the upper container (1), which is formed by discharged granular material and held in place by a discharge flange (20), which the common agitator shaft (6j6c) surrounds. 11. The device according to claim 7, characterized in, that the discharge outlet of the upper container has the shape of a cylindrical part of a downwardly sloping part of the bottom of the container that an adjustable in the vertical direction Trough (25) surrounds the common agitator shaft (6,6e) of the container (1,1e) and that a device (27) for adjustment of the trough (25) is provided at a distance (x) from the lower edge of the cylindrical part (15e) in order to regulate the discharge speed of the mixed particles emerging from the upper container can be discharged into the lower container. 12. The device according to claim 11, characterized by a Bypass pipe (16), which leads from the middle part of the upper container (1) to the upper part of the lower container (1c.) And through a control valve (24) in the bypass pipe (16). 13. The apparatus according to claim 11, characterized by a pair of air inlet pipes, one of which (I7) connects to the lower one End of the upper container (1) and the other (18) connected to the upper end of the lower container (1c), as well as by a second bypass pipe (19), which the, upper parts of the lower and upper container connects and contains a control valve. L'65 / 2 -14- 109309/1269