EP1000719A2 - Process and device for obtaining a sprayable concrete or mortar - Google Patents

Abstract

The spray concrete producing process involves producing a premix of binder and fine-grain additive, transporting it to the site and mixing a coarse-grain additive, brought in from the vicinity of the site, with it. The device used to implement the process has two pressure silos (3, 4), each with an issuing unit, a mixing device (8) and a transporting line (23) taking the mixture to a spray jet (24).

Description

The invention relates to a method for producing a Shotcrete or shot mortar on site, i.e. on a Construction site. The invention also relates to a Device, in particular for performing the above. Procedure, with two storage containers for holding two substances to be mixed with each other, each Storage container has a discharge member, via which the substance is discharged from the storage container, and a mixing device is provided in which the two Substances are mixed together, and a Transport line is provided, through which the Mixture of substances e.g. is fed to a spray nozzle.

EP 698 419 A1 describes a system for spraying Dry building materials became known. This facility owns a storage container in which the dry building material is stocked. There is one on this reservoir Compressed air line connected and the dry building material is conveyed from the storage container by means of compressed air. The Storage container is therefore designed as a pressure container. This has the main advantage that between the Transport line in which the dry building material is used Compressed air passed, and the reservoir no seal is required. Such seals are e.g. generated by rotary locks, via which the Dry building material transported on the one hand, on the other is dosed. Because the cells in turn in the lock are sealed, can in the delivery line Compressed air located in the storage container. However, it has been found that such Cell wheel locks, especially their seals relative wear out quickly and are therefore maintenance-intensive.

The storage container is usually dry Mixture of binder and aggregate filled, this Mixture usually over long distances to the construction site must be transported. This transportation is very costly and the provision of the dried Surcharge, which has a grain size in the range from 0 mm to 8 mm also has a relatively high cost connected because the aggregate is normally earth-moist.

To reduce costs, it has already been proposed just to transport the binder and the Surcharge to buy locally, so the transportation costs for the surcharge can be significantly reduced. It has also been proposed to add two reservoirs use, the dry in a storage container Binder and in other storage containers the surcharge is stocked. The supplement can be dry as well can also be stored moist in the silo. Since the knockdown in is usually moist, it is also stored moist. However, it turned out that due to the relatively large grain size range from 0 mm to 8 mm for a very high moisture content, on the other hand strong fluctuating moisture levels are present. Relatively small Grain sizes bind relatively due to their capillary action a lot of moisture, this moisture depending on the grain size mix of the aggregate, not evenly is distributed. In particular, it was observed that one prolonged standstill of the silo, e.g. overnight or over the weekend, the moisture within the surcharge sags and thus in the area of the lower outlet of the Surcharge is much wetter than in overhead Area. Will this very damp supplement now Binder admixed so there is a risk that through the premature hydration of the binder affects the quality of the Shotcrete or shot mortar is negatively affected. In addition, the constantly changing Moisture of the aggregate the amount of to be fed Water is very difficult and usually not exact to adjust.

The invention is therefore based on the object To provide methods and / or a device with a high-quality shotcrete or spray mortar at one relatively low price can be produced, or the Production of the binder aggregate mixture is relatively exact and is easy to do.

This problem is solved with a method in which a dry premix of binder and aggregate with a Grain size in the range from 0 min to 6 mm, in particular from 0 mm to 4 mm delivered and possibly in a storage silo is filled, a surcharge with a grain size in the range from 2 mm to 8 mm, in particular from 4 mm to 8 mm on site is stocked, i.e. is delivered up close, that Premix and the surcharge in the desired Mixing ratio to a binder aggregate mixture are mixed, and the binder additive mixture required amount of liquid, especially water is added.

This method according to the invention provides that neither complete binder aggregate mixture in dry form a long journey to the construction site is transported, nor that just the binder in dry form is fed, but that a premix of binder and premium as a premix over the long distance is transported. The further surcharge will be on site bought and only needs a short distance be transported. This premix consists of the Binder and the fine-grained aggregate, the one Grain size in the lower range. This lower one The range includes all grain sizes, which are relatively high Have or create capillary action. This premix is now in dry form over the further distance which has the advantage that only a part of the finished binder aggregate mixture are transported got to. The transport costs compared to the above Process in which the entire binder aggregate mixture transported are therefore lower.

Another advantage is the method according to the invention seen in that the moisture content in the site Purchased surcharge low on the one hand, relative on the other is evenly distributed. This surcharge is relative coarse-grained and can be stored in a moist form. The capillary action is due to the relatively large grains reduced and the moisture distribution evenly, because a drop in moisture as described above does not is to be feared. Now the premix and the Supplement mixed together, you get one Binder aggregate mixture, which on the one hand is a very has high quality, on the other hand is relatively inexpensive, since the largest percentage of the surcharge is not over long distances must be transported. In addition, the handling of the coarse grain surcharge on site, i.e. the metering under Taking moisture into account, relatively simple. Since the Moisture distribution within the coarse-grained Surcharge is relatively constant there are no wet ones Nests so that there is no premature hydration of the Binder is to be feared, so the quality of the Shotcrete is relatively high. The surcharge can be like already mentioned, in moist, i.e. earth moist condition or be stored dry on site.

According to one embodiment, it is provided that Premix and / or the surcharge in a pressure silo be stocked. Stocking the fabrics in one The pressure silo has the main advantage that none Sealing elements are required which prevent the Compressed air used for mixing and as transport air into the storage silos. The premix and / or the award is made by means of discharge organs, e.g. Cell wheel locks, screws or other dosing devices deducted. The substances are in a stream of compressed air mixed together. The premix and / or the aggregate and / or the binder aggregate mixture by means of the compressed air flow to a spray nozzle transported. The water is then in the spray nozzle added. In one variant, that at a defined distance in front of the spray nozzle part of the water is already added, which makes the Dust content reduced when spraying the shotcrete becomes.

One embodiment provides that by means of a Weighing method of the two silos the composition of Premix and surcharge is determined. By means of the Weighing method is measuring the change in weight that experience the silos when the fabrics are removed. Through the Weight change can be the mass of the stripped fabrics determined and thus determined the mixing ratio become.

In particular, the premix and / or the surcharge by means of a screw conveyor from the storage silo (s) promoted. By controlling the screw conveyors, the Quantity of the substance withdrawn (premix or surcharge) changed and thus the mixing ratio changed become.

The deducted premix and the deducted surcharge are fed to and in a screw conveyor Screw conveyor mixed together. This mixture can be supported with compressed air. From the Mixing device then becomes the premix and the aggregate or the already partially manufactured Binder additive mixture conveyed with compressed air and further mixed in the compressed air flow.

According to the invention, the object mentioned at the outset is achieved by means of a device according to the preamble of claim 9 solved, which is provided that the two Storage containers are designed as pressure silos that both substances mixed in a compressed air stream and over this compressed air flow are promoted.

By using pressure silos for the storage of the both substances, i.e. for the storage of the premix and, as already mentioned, the surcharge becomes the advantage achieved that no seals at the discharge opening of the Silos are required and that in a relatively simple way high-precision mixtures can be produced. Mixing the individual substances to the substance mixture takes place in Compressed air flow, with a premix in one Mixing device can be done, which is a snail has, which is flowed through by the compressed air. Under Snails are both rotating screw conveyors understood as well as on an inner circumference of a sleeve provided helical guide devices, which one a flow of swirl flowing through the sleeve imposition.

The pressure silos sit on top for optimal mixture generation Weighing devices, in particular pressure cells, on which exactly determines the weight of the discharged substances can be. These pressure cells are with a Coupled computing device, via which the weight of the discharged substances and thereby the Mixing ratio of the two substances can be calculated can. To adjust the mixing ratio are the Discharge devices can be controlled, in particular the speed the screw conveyor changeable.

Figur 1

eine Seitenansicht der erfindungsgemäßen Vorrichtung;

Figur 2

ein Prinzipschema eines ersten Ausführungsbeispiels der erfindungsgemäßen Vorrichtung; und

Figur 3

ein Prinzipschema eines zweiten Ausführungsbeispiels der erfindungsgemäßen Vorrichtung.

Further advantages, features and details of the invention emerge from the subclaims and the following description, in which two particularly preferred exemplary embodiments are described in detail with reference to the drawing. The features shown in the drawing and mentioned in the claims and in the description can each be essential to the invention individually or in any combination. Show in the drawing.

Figure 1

a side view of the device according to the invention;

Figure 2

a schematic diagram of a first embodiment of the device according to the invention; and

Figure 3

a schematic diagram of a second embodiment of the device according to the invention.

Figure 1 shows a side view of the invention System, which in the present example has two storage silos 1 and 2 have. In these storage silos 1 and 2 there are two Stocks of substances to be mixed together. Should more than two substances, e.g. three fabrics together are mixed, then the invention Device three storage silos. In the storage silo 1 e.g. there is a surcharge 7, e.g. coarser River sand, especially with a grain size in the range of 2 mm to 10 mm, preferably from 4 mm to 8 mm is damp. There is a in storage silo 2 Premix 9 of binder and a fine-grained Surcharge, especially with a grain size in the range of 0 mm to 7 mm, preferably from 0 mm to 4 mm Premix 9 is dry. The two storage silos 1 and 2 are designed as pressure silos 3 and 4. To deduct the Surcharge 7 from the pressure silo 3 is in its bottom area a screw conveyor 5 is provided by a electric drive 6 is driven and the supplement 7th out of the pressure silo 3 and a mixing device 8 feeds. The premix 9 flows over one Slider closure 10 to a screw conveyor 11 via which the premix 9 also the mixing device 8th is forwarded.

The two pressure silos 3 and 4 stand with their stands 13 on pressure cells 12, via which the weight of the Pressure silos 3 and 4 with ingredient (surcharge 7 and Premix 9) can be determined. The pressure cells 12 are with a computing device (not shown) linked, which in turn the drive 6 or Screw conveyor 11 controls.

Figure 2 shows a schematic diagram of a first Embodiment of the device according to the invention, where 14 denotes a compressor is. Several of this compressor 14 go Compressed air lines 15 to 19. The compressed air line 19 opens into the pressure silo 3 in the area of the screw conveyor 5 and directs compressed air into the screw conveyor 5, whereby the Discharge is supported. The pressure in the pressure silo 3 is by means of the supplied via the compressed air line 18 Maintain compressed air. The discharge of the surcharge 7 from the pressure silo 3 via the screw conveyor 5 and the line 20 into the mixing device 8.

The screw conveyor 11 of the pressure silo 4 is also via the compressed air line 15 and the pressure silo 4 via the Compressed air line 16 connected to the compressor 14. The The premix 9 is discharged by the Screw conveyor 11 and line 21 in the Mixing device 8.

This mixing device 8 is via the compressed air line 17th also connected to the compressor 14 and is with Compressed air applied. Both supplement 7 and that Premix 9 are in the mixing device 8 by means of a Auger 22 transported and mixed together and into the air by means of the compressed air blown in at the back Blown in thin current line 23. In a spray nozzle 24 is the binder aggregate mixture via a line 25th Water is supplied and the shotcrete produced is sprayed out.

In the alternative shown in Figure 3 The embodiment is located in the thin-current line 23 an intermediate humidifier 26 over which a part of the water to be added to the binder aggregate mixture is supplied before it reaches the spray nozzle 24. The distance between the intermediate humidifier 26 and the Spray nozzle 24 is defined so that no premature Hydration of the binder is to be feared. At this Variant of the device according to the invention can Dust formation when spraying the shotcrete be significantly reduced.

The invention thus relates to a method for manufacturing a shotcrete or shotcrete, in which a Premix of binder and small-grain aggregate is produced, which is transported to the construction site and spot this premix with a coarse grain Supplement is mixed, the coarse-grained aggregate is transported close to the construction site. The The invention also relates to a device with which two Mixtures of substances quickly and precisely mixed together can be.

Claims (12)

Process for the preparation of a shotcrete or shot mortar on site, ie at a construction site where a dry premix (9) of binder and aggregate with a grain size in the range from 0 mm to 6 mm is delivered and, if necessary, is filled into a storage silo (2), a surcharge (7) with a grain size in the range from 2 mm to 8 mm is purchased and stored on site, the premix (9) and the aggregate (7) are mixed in the desired mixing ratio to form a binder aggregate mixture, and the required amount of liquid, in particular water, is added to the binder additive mixture. A method according to claim 1, characterized in that the supplement (7) in damp, in particular earth-moist condition or stored dry on site becomes. Method according to one of the preceding claims, characterized in that the premix (9) and / or the surcharge (7) in a printing silo (4, 3) are stored. Method according to one of the preceding claims, characterized in that the premix (9) and / or the supplement (7) by means of discharge organs deducted and in a stream of compressed air with each other be mixed. Method according to one of the preceding claims, characterized in that the premix (9) and / or the supplement (7) and / or that Binder aggregate mixture using a Compressed air flow to a spray nozzle (24) be transported. Method according to one of the preceding claims, characterized in that by means of a Weighing method of the two silos (3, 4) Composition of premix (9) and aggregate (7) is determined. Method according to one of the preceding claims, characterized in that the premix (9) and / or the supplement (7) by means of a screw conveyor (11, 5) from the storage silo (s) (1, 2) be promoted. Method according to one of the preceding claims, characterized in that the premix (9) and the supplement (7) is fed to a screw conveyor (22) and be mixed together in this. Device, in particular for carrying out a Method according to one of the preceding claims, with two storage containers (1, 2) for holding two substances to be mixed with each other, each Storage container (1 and 2) has a discharge member, through which the substance from your storage container (1 or 2) is discharged, and a mixing device (8) is provided in which the two substances be mixed together, and one Transport line (23) is provided, via which the Mixture of substances e.g. fed to a spray nozzle (24) is characterized in that the two Storage containers (1, 2) as pressure silos (3, 4) are trained that the two substances in one Compressed air flow mixed and over this compressed air flow be promoted. Apparatus according to claim 9, characterized in that as a mixing device a screw (22) is provided, which is flowed through by compressed air. Apparatus according to claim 9 or 10, characterized characterized that weighing devices, in particular Pressure cells (12) are provided, on which the Mount the pressure silos (3, 4). Device according to claim 11, characterized in that a computing device is provided that the Computing device linked to the weighing devices is and that about the computing device Mixing ratio of the two substances can be determined and is adjustable by means of the discharge organs.

Images