EP0051224B1 - Process and apparatus for the continuous preparation of mortar, plaster or the like building material - Google Patents

Description

The invention relates to a method for the continuous preparation of mortar, plaster, concrete or the like. Building material or material, in which the material is fed to a metering device and then mixed with liquid. is mixed at the same time and fed to a discharge opening, the mixture being stowed in the area of the water supply and / or in the conveying direction behind it and being stirred in the meantime, while a quantity of material exceeding the stowed quantity emerges from the mixing area and the discharge opening.

The invention further relates to a device for the continuous preparation of mortar, plaster, concrete or the like. Material with a feed or loading device, a metering device for the dry material adjoining it, a liquid addition point and a tubular mixing chamber, a metering screw being provided in the metering area and a rotating shaft with stirring or mixing tools and conveyor blades or the like being provided in the metering area and the like A discharge opening is arranged at the end of the mixing chamber.

A method of the type mentioned at the outset is essentially known from DE-C-360 266. In this case, a baffle wall is provided at the end of the mixing space, so that only a quantity exceeding the quantity of material stowed by this wall can exit the outlet opening for the mixed material. In this case, dead spaces are unfavorably formed in the area of this baffle wall, so that at least after a long period of operation an interruption in operation and cleaning of the device is necessary in order to remove this material, which has been removed from the further work process, from the dead spaces.

From DE-C-461 22o a trough mixer is known in which the bottom of the trough rises slightly at an angle. However, this makes it practically impossible for the material to be stowed, since the Ford scoops extending into this base area continuously move the material to the discharge opening which is not provided with a jam plate. The slight rise in soil serves to bring the mixing water safely into the area of the feed opening for the dry material in order to achieve good moisture penetration. However, there is a risk that the water will also penetrate into the dry feed area for the material, which is undesirable.

From FR-A-2 382 992 a device for the continuous preparation of mortar, plaster, concrete or the like material is known, which has a metering screw between the supply area for the dry material and the area for preparation with water.

However, the mixing chamber opens into a discharge opening without a jam protruding from below, which is only partially closed from above by a bearing bracket. A material jam is only possible if more material accumulates than the discharge opening directly from the floor can release. If a jam occurred, there was again the disadvantage that dead spaces were formed in the area of the jammed wall.

In both DE-C-36o 266 and FR-A-2 382 992, in the event of a jam, part of the material is simply fixed and takes no or hardly part in the mixing processes, so that the remaining part of the material is conveyed over this material portion located in a dead space and then in turn is not exposed to the mixing tools for a sufficient period of time in order to be able to mix in large amounts of air, which can later increase the thermal insulation, for example, within wall cleaners or the like. This applies all the more to the device according to DE-C-461 22o, in which, although no material can remain in a dead space, the entire material flow is continuously discharged and therefore there is little or no time to additionally mix in a significant amount of air.

The object is therefore to create a method and a device of the type mentioned at the outset with which the air content in the material being made can be increased in a simple manner.

With regard to the method, the solution to this problem is that the material which has been brought into contact with water is subjected to counter-conveyance from the outlet from the mixing zone which is less than the conveyance in the conveying direction. This counter-promotion causes: in the desired manner, a restraint of the material without completely preventing its escape and without leading to a jam of part of the material in a dead space. At the same time, an additional mixing effect with additional introduction of air pores can be generated by such counter-promotion.

It is particularly favorable for the admixing of air if the mixing chamber has more than 50%, preferably more than 60% to 70% of its internal volume during operation, in particular after deducting the volume taken up by the agitator shaft, but with less than 100%. preferably less than 90% is filled.

The residence time of the mixture in the mixing chamber can be selected to be longer than 15 to 20 or 30 seconds, preferably 40 to 60 seconds, and the circumferential speed at the outer agitator diameter can be approximately 2 to 3 meters per second, preferably approximately 2.5 meters per second.

As already mentioned at the beginning, the invention also includes a device for the continuous preparation of mortar, plaster, concrete or the like material, as is known from FR-A-2 382 992. This mentioned at the beginning The device is said to be particularly suitable for carrying out the method according to the invention and is characterized in order to achieve the stated object in that the mixing chamber in the area in front of and / or at the discharge opening in the conveying direction has a conically narrowing longitudinal section such that a counter-conveying of part of the material is achievable.

So far, it has been assumed in such mixing devices, in particular for building materials, that the mixture should be discharged as smoothly and continuously as possible so that it can be processed accordingly. The few examples with baffle walls revealed dead spaces that hindered this smooth discharge. Due to the conical design of the mixing chamber in front of and / or at the discharge opening, a counter-conveyance of the material is now achieved on the one hand, whereby this material is exposed to the mixing tools for a longer time, so that more air can be mixed in, while at the same time continuous discharge is made possible without Parts of the material remain in dead spaces. A material jam results from the fact that the material has to rise towards the end of its conveying in the mixing chamber via a slope which causes the counter-conveying mentioned, that is to say a counterforce.

It can be arranged in the conically narrowing area with its outer edge adapted to the slope of this area stirring tool. This means that additional air pores can also be introduced into the material in this area. It is particularly important that the bottom of the tapered area of the mixing chamber rises at the discharge opening.

Another embodiment of the invention of its own worthy of protection may consist in that at least one damming element is attached to the shaft carrying the mixing tools and rotates with it. As a result, this baffle element can in turn participate in the mixing process by its movement and, with a corresponding design, can support the introduction of air into the mixture.

As a baffle element, a disk, a ring or the like can be attached to the shaft, which has passages on the inside and / or on the outside opposite the housing of the mixing chamber openings or the like. In this case, the damming element fastened to the shaft can carry projections, wings, blades or the like. Additional mixing devices, so that this element has a double function by, on the one hand, jamming the material in the desired manner and, on the other hand, because of its rotation, additionally as a mixing and Stirring tool is used.

Both in the above-described embodiment and in a modified embodiment of the invention, an embodiment is possible which, due to its apparent contradiction, has its own meaning worthy of protection. It is namely possible that, seen in the conveying direction, conveyor vanes, blades or the like acting at the end of the mixing shaft against the conveying direction are provided. The counter-conveyance caused by this not only causes material to jam, but also causes additional movements within the material that increase the air intake.

The counter-acting conveying vanes or blades can have approximately the same conveying effect as the conveying vanes or vanes provided overall in the mixing area, so that the material feed is brought about by the pressure exerted by the metering screw in the conveying direction.

Overall, a particularly expediently designed and well-effective device results if at least one row of conveying vanes located at the circumference of the shaft and at the end the baffle element, in particular the vanes acting against the conveying direction, as well as conveying-neutral mixing or stirring tools are arranged in between at the beginning of the mixing chamber . The material is mainly stirred through most of the mixing chamber and a corresponding amount of air can be mixed in. A further advantageous embodiment is given in expression 13.

A considerable advantage of the rotating dam elements is that the mixing chamber can have a substantially constant cross section over its entire length, tapering only at the end, so that enlargements of the chamber or the like make production difficult or a trough with a rising bottom or the like can be avoided.

Overall, there is a device and also a method for switching on building materials in particular, with which the absorption of air in the made-up material can be increased considerably, so that this material has a lower weight in the processed state, while at the same time increasing the insulating effect . The cleaning material, which is often quite expensive, can not only be improved in its effect in this way, but can also be used sparingly. Dead spaces that reduce or even destroy the traffic jam effect after filling up are avoided.

• Fig. 1 in schematischer Darstellung einen Längsschnitt durch eine Vorrichtung zum Anmachen von Mörtel od. dgl., bei der ein eine Gegenförderung bewirkendes Stauelement in Form von Gegenflügeln mitdrehend auf der die Rührwerkzeuge aufweisenden Welle angeordnet ist,
• Fig. 2 in vergrößertem Maßstab einen Querschnitt durch den die Gegenflügel tragenden Bereich der Mischkammer entlang der Linie V-V in Fig. 1,
• Fig. 3 einen Längsschnitt durch eine Mischkammer, bei der an der sich drehenden Welle nahe der Austrittsöffnung eine sich mitdrehende Ringscheibe angeordnet ist,
• Fig. 4 einen Querschnitt der Mischkammer im Bereich der sich mitdrehenden Ringscheibe und ihrer Befestigung an der Welle gemäß der Linie VII-VII in Fig. 3,
• Fig. 5 einen Längsschnitt durch eine Mischkammer mit einem im Bereich der Austragsöffnung enger werdenden Querschnitt und
• Fig. 6 einen Querschnitt durch den Endbereich der Mischkammer gemäß der Linie IX-IX der Fig. 5..

In the following, the invention is described with its details, which belong to it as essential, with reference to the drawing in several exemplary embodiments, which show suitable devices for carrying out the method. however, only the embodiment according to FIGS. 5 and 6 falls under the wording of the device claims. It shows

• Fig. 1 shows a schematic representation of a longitudinal section through a device for Putting on mortar or the like, in which a damming element, which brings about counter-conveying, is arranged in the form of counter-blades and rotates on the shaft having the stirring tools,
• FIG. 2 shows, on an enlarged scale, a cross section through the area of the mixing chamber that bears the counter-wings along the line VV in FIG. 1,
• 3 shows a longitudinal section through a mixing chamber, in which a rotating rotating disk is arranged on the rotating shaft near the outlet opening,
• 4 shows a cross section of the mixing chamber in the region of the rotating rotating ring disk and its attachment to the shaft according to line VII-VII in FIG. 3,
• 5 shows a longitudinal section through a mixing chamber with a cross section which becomes narrower in the region of the discharge opening and
• 6 shows a cross section through the end region of the mixing chamber along the line IX-IX of FIG. 5 ..

A device for making mortar, for example placed on a running gear, has an inlet and a connecting piece 2. The latter leads to a horizontally running loosening space 3.

An electric motor 4 is connected to one side of this loosening space 3, the horizontally running shaft 5 of which has blades 6 in the loosening space, which convey the loosened dry material to a dosing screw 7.

The cylindrical space captured by the dosing screw 7 has a much smaller diameter than the loosening space 3.

In the illustrated embodiments, a mixing device or mixing chamber 8 is connected to the dosing device, which has a water addition 9 and is detachably flanged to the tubular part forming the loosening space 3 and the dosing space. The shaft 5 also extends straight into the mixing chamber 8. The mixing tools 11 can be conventional mixing paddles, some of which provide for mixing and some of which promote the mixing material.

As can be seen, for example, from FIGS. 5 and 6, the discharge opening 17 of the mixing chamber 8 is substantially smaller than the diameter thereof. In a mixing chamber 8 which is usually non-rotating, the discharge opening 17 can be arranged asymmetrically. Of course, the inlet with the connection piece 2 can be provided below a silo and the device according to the invention for mixing mortar can be connected to this silo in a fixed or detachable manner.

From the outlet from the mixing zone, the material that has been mixed with water is subjected to counter-conveyance, which will be described below, which is less than the conveyance in the conveying direction in order to expose the mixed material to a longer residence time in the mixing chamber 8 and thus the number of air pores within one To increase the mix.

In the exemplary embodiment according to FIGS. 5 and 6, the desired counter-promotion of the mixing chamber 8 is brought about by the design through this chamber 8 in the region of the discharge opening 17. The mixing chamber 8 has namely in this area in front of and at the discharge opening 17 in the conveying direction such a narrowing, in the exemplary embodiment tapering longitudinal section that counter-conveyance of a part of the material can be achieved. The cross section decreases steadily towards the discharge opening 17. As a result of this narrowing, the material conveyed to the discharge opening 17 is exposed to a counterforce and thus to a counter-promotion, above all due to the increase in the base region. In addition, the discharge opening 17 can be correspondingly narrow.

In this area, with its outer edge 13 there is also a stirring tool 25 adapted to the bevel of the taper 24. The material jammed in the taper 24 is therefore additionally mixed by the stirrer 25, so that a corresponding introduction of air pores can also be expected in this area. If necessary, it could be sufficient if only the bottom 26 of the mixing chamber rises in front of or at the discharge opening 17 in order to achieve the effect of the counterforce and counter-promotion.

In the exemplary embodiments according to FIGS. 1 to 4 it is provided that the counter-conveying element serving to extend the dwell time of the material to be mixed is fastened to the shaft 5 carrying the mixing tools and rotates with it.

1 and 2 show an exemplary embodiment in which conveyor blades 27 acting against the conveying direction are provided at the end of the mixing shaft 5 in the conveying direction. 2 shows three evenly distributed conveying vanes 27 of this type, which according to FIG. 1 are arranged just before the discharge opening 17. These conveying vanes 27 operating in the opposite direction to the conveying vanes 28 located at the beginning of the mixing chamber 8 could have approximately the same conveying effect as the aforementioned vanes 28, so that the material feed through the mixing chamber 8 is carried out by the pressure exerted by the metering screw 7 in the conveying direction.

In the exemplary embodiment according to FIGS. 3 and 4, the shaft 5 is fastened to an annular disk 29, which has 8 openings or through-slits both in its interior 30 and on its outer edge 31 with respect to the mixing chamber housing. An agitator 11 is connected directly to this ring 29, which increases the stability of the fastening of the ring disks 29. 4 mi thereby that, for example, three webs 32 can support the washer 29.

Both in the embodiment of FIGS. 1 and 2 and in that of FIGS. 3 and 4 are at the beginning of the mixing chamber 8 a row of conveying vanes 28 located on the circumference of the shaft 5 and at the end the counter-conveying element and in between the conveying-neutral mixing or Stirring tool 11 arranged. As a result, this space in particular is practically fully utilized as storage space, in which these stirring tools 11 can introduce as much air as possible into the material mixed with water at the same time. In the exemplary embodiments according to FIGS. 4 to 6, the mixing and stirring tools 11 are designed as grids in order in turn to intensify the introduction of air.

Except for the conical taper 24, the mixing chambers 8 are each provided with essentially the same cross-section over their entire length, so that they can be manufactured, for example, from a tube or the like. In addition, this makes it easy to clean a mixing chamber 8, which can be separated from the metering area, for example, it being advantageous that the counter-conveying element remains on the shaft 5.

It is particularly advantageous if, in one or more of the devices described above, the respective filling volume in the mixing chamber 8 during operation is more than 50%, preferably even more than 60 to 70%, of the respective inner volume of the mixing chamber 8. The volume occupied by the shaft 5 and the stirring tools 11 may need to be taken into account accordingly. In any case, however, the filling volume should be less than 100% and preferably less than 90% of the total inner volume. It has been shown that a good loading and intensive introduction of air pores into the mixture is possible in this way.

The residence time of the mixture in the mixing chamber 8 is preferably more than 20 or 30 seconds and, particularly in the exemplary embodiment according to FIGS. 5 and 6, is expediently of the order of 40 or more seconds. In the other exemplary embodiments, too, a residence time is expedient which allows sufficient air pores to be stirred into the material. It is advantageous if the peripheral speed on the outer agitator diameter is 2 to 3 m per second and preferably about 2.5 m per second. Depending on the embodiment of the stirring tools, certain deviations from these values may be appropriate. If the peripheral speed is too slow or too fast, the result is less favorable.

It should also be mentioned that the invention can also be practiced in that the shaft 5 carries several baffle elements distributed over its length in the region of the mixing chamber 8, these baffle elements in each case being counter-vanes or parts thereof. These are expediently connected to the stirring tools 11 in FIG. 1. It is conceivable, for example, to design the ends of the stirring tools 11 in FIGS. 1 or 3 and 5 as blades which act partially counter to the conveying direction, so that there is a corresponding build-up of the stirred material and therefore a correspondingly long dwell time.

Claims (13)

1. A process for the continuous preparation of mortar, plaster, cement or like building material, wherein the material is supplied to a metering device and thereafter mixed with liquid, is simultaneously blended and supplied to a discharge opening (17), the mixture being accumulated in the region of the water supply and/or behind it in the direction of feed and meanwhile being agitated, while an amount of material exceeding the accumulated amount passes out of the mixing zone and the discharge opening (17), characterized in that from the outlet of the mixing zone onwards the material prepared with water undergoes a counter-feeding action which is less than the feeding action in the direction of feed.

2. The process as claimed in claim 1, characterized in that during operation the mixing chamber (8) is charged with more than 50%, preferably more than 60 to 70% of its inner volume, in particular after deduction of the volume occupied by the agitator shaft, but with less than 100%, preferably less than 90%.

3. The process as claimed in claim 1 or claim 2, characterized in that the residence time of the mixture in the mixing chamber (8) is selected to be longer than 15 to 20 or 30 seconds, preferably 40 to 60 seconds and that the peripheral speed at the outer diameter of the agitator is approx. 2 to m/sec, preferably about 2.5 m/sec.

4. An apparatus for the continuous preparation of mortar, plaster, cement or like building material comprising a feed or charging device (2) followed by a metering device for the dry material, a location (9) for adding liquid and a tubular mixing chamber (8), in the metering zone there being provided a metering screw (7) and in the mixing chamber (8) there being provided a rotating shaft (5) with agitating or mixing tools (11) and feeding blades (28) or the like and a discharge opening (17) being disfor performing the process as claimed in any one of claims 1 to characterized in that in the zone before and/or at the discharge opening (17) the mixing chamber (8) has a longitudinal section narrowing conically in the direction of feed in such a manner as to enable part of the material to be counter-fed.

5. The apparatus as claimed in claim 4, characterized in that an agitating tool (25) is disposed in the conically tapered zone (24) and with its outer edge (23) is adapted to the slant of said zone (24).

6. The apparatus as claimed in claim 4 or clain 5, characterized in that the base (26) of the tapered zone (24) of the mixing chamber (8) rises at the discharge opening (17).

7. The apparatus in particular as claimed in an one of claims 4 to 6, characterized in that at leasi one accumulating element is secured to the shaf (5) bearing the mixing tools and is entrained.

8. The apparatus as claimed in claim 7, characterized in that in the form of an accumulating element there is secured to the shaft (5) a disc (29), a ring or the like which has openings or similar passages on the inside (30) and/or on the outside (31) opposite the housing of the mixing chamber (8).

9. The apparatus as claimed in claim 7 or claim 8, characterized in that the accumulating element secured to the shaft (5) has projections, fins, blades or similar additional mixing means.

10. The apparatus in particular as claimed in any one of claims 4 to 9, characterized in that viewed in the direction of feed there are provided at the end of the mixing shaft (5) feeding fins (27), blades or the like counteracting the direction of feed.

11. The apparatus as claimed in claim 10, characterized in that the counteracting feeding fins (27) or blades have approximately the same feeding effect as all the feeding fins (28) or blades provided in the mixing zone, so that the advance of the material is caused by the pressure additionally exerted by the metering screw (7) in the direction of feed.

12. The apparatus as claimed in any one of claims 4, 7, 9, 10 or 11, characterized in that at least one row of feeding fins (28) located on the circumference of the shaft (5) is disposed at the beginning of the mixing chamber (8) and at the end is disposed the accumulating element, in particular the fins (27) counteracting the direction of feed and inbetween mixing or agitating tools (11) which are neutral with regard to the direction of feed.

13. The apparatus as claimed in any one of claims 4 to 12, characterized in that in the region of the mixing chamber (8) the shaft (5) bears a plurality of accumulating elements, preferably counteracting fins (27) which are distributed over its length and are preferably connected to the agitating tools (11).

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