WO2018108678A1

WO2018108678A1 - Mixing nozzle for a shotcrete application device, and a shotcrete application device comprising such a mixing nozzle, and a shotcrete application method

Info

Publication number: WO2018108678A1
Application number: PCT/EP2017/081749
Authority: WO
Inventors: Sebastian Bender; Stefan Scheffler; Bertram Kesselheim
Original assignee: Refratechnik Holding Gmbh
Priority date: 2016-12-12
Filing date: 2017-12-06
Publication date: 2018-06-21
Also published as: EP3551408B1; RU2730720C1; DE102016124101A1; EP3551408A1

Abstract

The invention relates to a mixing nozzle (8) for a shotcrete application device (1) for spraying concrete, in particular refractory concrete, using a dry-mix process, and also to a shotcrete application device (1) of this type and a shotcrete application method, in particular for applying refractory concrete. The mixing nozzle (8) comprises: a) an aerosol-generating device (55) for generating an aerosol from a liquid or dry flowable injection material and conveying air, and b) an aerosol-injecting device (56) for injecting the aerosol, in particular centrally, into the interior of a dry material flow consisting of a dry mixture.

Description

Mixing nozzle for a shotcrete application device, as well as shotcrete application device with such a mixing nozzle and shotcrete application method

The present invention relates to a mixing nozzle or injection nozzle for a shotcrete application device for dry spraying of concrete, in particular fireproof concrete, as well as such a shotcrete application device and a shotcrete application process or dry spray process, in particular for applying refractory concrete.

Shotcrete is conveyed in a pipe or hose line to the installation parts, where it is pneumatically applied from a spray nozzle and compressed by the impact energy. In the dry spraying process, the dry, preferably hydraulic, binder, the additives and additives and the additives are dry pre-mixed and transported in a stream of compressed air through the pipe or hose line to a spray nozzle. In the spray nozzle water or a liquid binder is supplied to the dry mixture and generates a spray mass. Thereafter, the sprayed compound is sprayed onto the surface to be coated in an uninterrupted stream.

GB 2 025 794 A discloses a spray nozzle for applying shotcrete inter alia on building walls. The spray nozzle has an inlet end and an outlet end. At the inlet end, a powdered cement mixture is supplied. In addition, the spray nozzle has a mixing chamber in which the powdery cement mixture is mixed with water. For this purpose, a cylindrical sleeve is present, which surrounds the mixing chamber. The sleeve also has a plurality of radial bores through which the water enters the mixing chamber in the form of individual water jets. At the tapered outlet end of the spray nozzle emerges from the spray mass.

Fireproof concrete is made with a room temperature setting binder and refractory aggregates. The curing at room temperature binder causes the primary or cold bonding. The technological conditions are similar to those of conventional construction clay. Characteristic of Fire concrete is the transition from the primary or cold bond to the ceramic bond that occurs on the first heating. Fireproof concrete according to the invention has a pressure softening point T ₀ s according to DIN EN ISO 1893: 2009-09 of T ₀₅ ^ 600 ° C, preferably T ₀₅ > 800 ° C. Accordingly, refractory or refractory additives in the context of the invention are those additives which are suitable for a refractory concrete with the above-mentioned printer softening point T ₀₅ .

US Pat. No. 4,239,397 discloses a spray nozzle for applying fiber-reinforced shotcrete. The spray nozzle comprises a conduit for feeding the fibers and a conduit for supplying a dry mix of binder and aggregates, the conduits being arranged to introduce the dry mix tangentially into the stream of fibers. At an outlet end of the spray nozzle, water is introduced from a ring having radial openings radially from the outside into the flow of material from the dry mix and the fibers.

WO 2005/098333 A1 discloses a dry spraying process in which a premix of a first liquid and a dry mixture is produced in a mixing device and this premix is mixed at a spray nozzle with a second liquid to a shotcrete fresh mass. The first liquid may e.g. have a setting accelerator. After premixing, according to WO 2005/098333 A1, the setting process already begins. In the mixing device, the first liquid is supplied radially or slightly obliquely from the outside of the material flow of the dry mixture. In the spray nozzle, the water is also supplied by means of a water ring radially from the outside.

EP 1 153 861 A1 discloses a shotcrete application apparatus and method. According to EP 1 153 861 A1, a fine-grained, dry spray mass, which already contains hardener, is mixed with water in a mixing tube of a moistening device. The water is previously atomized in the humidifier with compressed air. It may be at the end of the mixed tube a re-wetting take place. According to a further embodiment, the hardener may be added during the rewetting. At the end of the mixing tube, a spray nozzle for applying the spray mass is arranged. WO 2010/105049 A2 discloses a dry spraying process for refractory concrete in which a dry mixture containing refractory material and a setting regulator is provided in a storage container. The dry mix is introduced into the air flow stream of a shotcrete application device. Furthermore, a liquid binder is mixed with the dry mixture at or shortly before the spray nozzle of the shotcrete application device. The resulting shotcrete fresh mass is then applied to the surface to be coated by means of the spray nozzle.

EP 0 738 676 A1 discloses a device for adding air, liquids or pulverulent solids in shotcrete lines. The device has an annular insert part which can be inserted into the delivery line and has an inlet channel opening into an annular chamber of the insert part and a plurality of outlet channels directed from the annular chamber to the delivery flow. The outlet channels are aligned obliquely to the conveying direction. Through the insert part, a powdery mixture is introduced into a flow. The flow can be an air / water mixture.

The object of the present invention is to provide a shotcrete application device for dry spraying concrete, in particular fireproof concrete, and a shotcrete application method, wherein the physical properties of the shotcrete to be applied are to be easily and quickly adaptable and optimizable.

Another object is to provide a mixing nozzle for such a shotcrete application device and / or such a shotcrete application method. These objects are achieved by a mixing nozzle according to claim 1, a shotcrete application device having the features of claim 20 and a shotcrete application method having the features of claim 22. Advantageous developments of the invention are characterized in the appended subclaims.

In the following the invention will be explained in more detail by way of example with reference to a drawing. Show it:

Figure 1: A schematic view of the shotcrete application device according to the invention Figure 2: A longitudinal section through the mixing nozzle according to the invention

Figure 3: A perspective view of the mixing nozzle according to the invention

FIG. 4: A perspective view of an inlet-side housing component of the mixing nozzle according to the invention

FIG. 5: a perspective view of a first middle component of the mixing nozzle according to the invention

FIG. 6: A perspective view of a second middle component of the mixing nozzle according to the invention

FIG. 7: a perspective view of an outlet-side housing component of the mixing nozzle according to the invention; FIG. 8: a perspective view of an injection tube of the mixing nozzle according to the invention;

FIG. 9: a longitudinal section of the injection tube

Figure 10: Cold bending strength REFRAJET Nanobond F-58 R

Figure 1 1: Cold compressive strength REFRAJET Nanobond F-58 R Figure 12: Cold bending strength REFRAJET Nanobond S-60 Figure 13: Cold pressure REFRAJET Nanobond S-60

Figure 14: Cold bending strength REFRAJET Nanobond C-84 AL

Figure 15: Cold pressure REFRAJET Nanobond C-84 AL

The shotcrete application device 1 according to the invention (FIG. 1) has a compressed-air source 2, three air-conveying lines 3a, 3b, 3c connected to it, an injection-material reservoir 4 filled with an injection medium or material, in particular an injection liquid, an injection material delivery line 5 connected thereto , preferably an injection material feed pump 50, as well as a dry mixture storage container 6 filled with a dry mixture or granulated dry material and the mixing nozzle 8 according to the invention. In order to be able to measure and control the flow rates of the injection material, an injection material flow meter 51, which is arranged within the injection material delivery line 5, is preferably also present. The injection material reservoir 4, the injection material delivery line 5, preferably the injection material delivery pump 50, preferably the injection material flow meter 51, the dry mix reservoir 6 and the mixing nozzle 8 are components of a unit referred to as an injection molding machine 7. The spraying machine 7 is either movable and has for this purpose preferably in a conventional manner wheels and preferably a handle for the operator. In this case, the injection molding machine 7 is thus a sprayer. However, the injection molding machine 7 can also be stationary, in particular be arranged stationarily under a silo. A first air conveying line 3a, the injection material conveying line 5 and the dry mixture reservoir 6 are each connected to the mixing nozzle 8 and lead the mixing nozzle 8 to the respective material or conveying air. A second air conveying line 3b is connected to the lower end of the dry mixture reservoir 6 and leads to the dry mixture Reservoir 6 conveying air for blowing the dry mixture from the dry mixture reservoir 6 to. In a manner known per se, a discharge device, for example a rotor or a pocket wheel, is present at the lower end of the dry mixture reservoir 6 (not shown), which conveys the dry mixture from the dry mixture reservoir 6 into a discharge nozzle (not shown) , The mixing nozzle 8 is connected directly or indirectly via an intermediate piece, such as a hose, to the Ausblasstutzen. The mixing nozzle 8 according to the invention thus serves to mix the individual components of the sprayed concrete to be applied, ie the injection material from the injection material reservoir 4 with the dry mixture from the dry mixture reservoir 6 to a, in particular pre-wetted, material mixture.

Furthermore, the shotcrete application device 1 according to the invention has a hose line 9 connected to the mixing nozzle 8, a spray nozzle 10, a liquid reservoir 1 1 filled with a liquid, preferably water or a liquid binder, and a liquid feed line 12 connected thereto and preferably a first and a second liquid feed pump 52, 53. In order to be able to control the flow rates of the liquid, the shotcrete application device 1 also preferably has a liquid flow meter 54, which is arranged inside the liquid feed line 12. In the first liquid feed pump 52, which sucks the liquid from the liquid reservoir 1 1, it is preferably a submersible pump. The second liquid feed pump 53 is preferably a high pressure pump. The second liquid feed pump 53 conveys the liquid to a liquid injection device, e.g. a water ring, the spray nozzle.

The hose line 9 and the liquid delivery line 12 are both connected to the spray nozzle 10 and lead this coming from the mixing nozzle 8, in particular pre-wetted, material mixture or the liquid. The hose 9 preferably has a length of at least 10 m up. The spray nozzle 10 thus serves in a conventional manner for mixing the, in particular pre-wetted, material mixture with the liquid to a Spritzbetonfrischmasse or spray mass, especially a Feuerbetonspritzmasse, and for spraying the spray mass, in particular the Feuerbetonspritzmasse on the respective substrate.

The injection material is preferably an injection fluid. However, the injection material may also be a pourable or loose dry material, in particular a dry mixture.

The injection material preferably contains at least one concrete additive or a concrete additive. Concrete additives or concrete admixtures are known to be added to the concrete, by chemical or physical action or by both the properties of fresh or hardened concrete, such as. B. processability, solidification, hardening or frost resistance to change. Setting additives or setting regulators influence the setting reaction, e.g. the solidification and / or hardening reaction, of the respective binder. Concrete admixtures are added (in contrast to concrete additives) in such small amounts (in total, ie the sum of all concrete admixtures <5 wt .-% based on the dry matter of the total sum of aggregates and binder of the concrete) that they are irrelevant as a proportion of the concrete , They are therefore not taken into account in the substance space calculation. Concrete additives or concrete admixtures can also serve as auxiliaries in the ceramic fire, which takes place in situ in the case of Feuerbetons after application of the Feuerbetons. Sintering aids e.g. lower e.g. the firing temperature. Additives or concrete admixtures are usually supplied in liquid, powder or granular form.

Preferably, the injection material contains at least one solidification accelerator and / or hardening accelerator and / or retarder and / or plasticizer and / or a dust binder and / or a gelling agent. Gelling agents are known to initiate gelation of the binder. The solidification accelerator is used in a conventional manner to stimulate the solidification reaction of the binder and thereby increases the early strength. The solidification accelerator in the case of the liquid injection material is preferably water glass or alkali solutions. In addition, the dry injection material may contain cement and / or dry phosphates as accelerators.

If the injection material is liquid, it is in particular a suspension and / or solution and / or emulsion. Preferably, the liquid injection material is at least hydrous. The liquid injection material may also be (additionally) oil and / or alcohol and / or glycerol-containing.

If the injection material is a dry material or mixture, it is a powdery material or mixture having a particle size <0.5 mm, preferably <0.1 mm in accordance with DIN EN ISO 1927-3 (March 2013).

As already explained, the liquid or dry injection material may also contain further constituents, in particular pulverulent constituents. For example, the injection material may contain microsilica or fumed silica or Aerosil or MgO, which act as a sintering aid during the ceramic, in-situ firing of the fire concrete. The sintering aids do not or not significantly contribute to cold bonding, so they do not or not significantly interfere with the setting reaction of the shotcrete.

Furthermore, the injection liquid may also be pure water.

The free-flowing or loose dry mixture consists of granular and optionally fibrous material. The dry mixture can consist exclusively of material which is essentially inert, ie it does not react or only slightly reacts with the particular binder supplied to the spray nozzle 10. In particular, no setting additives or setting additives are therefore contained in the dry mixture. When it comes to refractory concrete, the dry mixture preferably consists exclusively of mineral and refractory or refractory material or aggregate. As already explained above, refractory or refractory materials or additives in the sense of the invention are materials or additives which are suitable for a refractory concrete with the above-mentioned printer softening point T ₀₅ . Preferably, the dry mix comprises grains of the following materials:

Andalusite and / or Cordierichamotte and / or basalt and / or bauxite and / or expanded and / or light chamotte and / or chrome ore and / or chromium corundum and / or Corhart Zac (zirconium silicate) and / or precious corundum (WFA) and / or brown corundum ( BFA) and / or hollow spherical corundum and / or kerphalite and / or kyanite and / or sillimanite and / or magnesia and / or microsilica and / or calcined clays (reactive clays) and / or chamotte and / or olivine and / or perlite and / or vermiculite and / or recycling raw materials (sanitary porcelain, insulator porcelain, slide plate fracture, chamotte fracture, etc.) and / or quartz and / or quartz glass (fused silica) and / or silicon carbide and / or spinel and / or mullite and / or zirconium mullite and / or or tabular earth and / or graphite or another carbon carrier and / or clay and / or zirconium oxide and / or zirconium sand. However, the dry mixture may additionally contain at least one, in particular pulverulent, binder. Preferably, it is a mineral binder. In particular, the dry mixture comprises, as binder, clay and / or alumina cement and / or Portland cement and / or pulverulent water glass preparations and / or powdered phosphate preparations, in particular alumetaphosphate and / or monoaluminum phosphate, and / or dry resins and / or silicate binder.

The dry mixture preferably has both coarse and medium-grained and fine-grained constituents or coarse and medium grain fractions (> 0.063 mm according to DIN EN ISO 1927-3 (March 2013)) and flour grain fractions (<0.063 mm according to DIN EN ISO 1927 -3 (March 2013)). Prefers the dry mixture has the following particle size distribution according to DIN EN ISO 1927-3 (March 2013) (the proportions are based on the total dry matter and add up to 100% by weight):

As already explained, the liquid which is added to the nozzle nozzle 10 is pure water or liquid binder or a concrete additive containing liquid.

If, for example, the dry mix and / or the injection material contains sufficient binders and concrete admixtures, water is preferably added exclusively.

The liquid binder is preferably a solution or suspension in water or other solvent or liquid polymer, preferably synthetic resin. The suspension preferably contains dispersed, colloidal particles. The liquid binder is preferably cementless and solidifies and hardens directly after spraying as a result of the reaction with the additives contained in the injection material. In the case of Feuerbetons the liquid binder thus provides for the primary, so-called cold bonding.

Preferably, the liquid binder is a refractory or refractory liquid binder, which is thus suitable after hardening for use in a refractory concrete with the above-mentioned printer softening point.

The liquid binder is preferably silica sol or water glass, preferably sodium and / or potassium and / or Li water glass, or phosphoric acid or monoaluminum phosphate or a polymer binder, preferably Synthetic resin, preferably phenolic resin, in particular novolak, or mixtures of the abovementioned binders.

The liquid binder preferably contains no concrete additives or concrete admixtures. He can, however, e.g. Contains an antifreeze that prevents the liquid binder from freezing before mixing at low temperatures.

The mixing nozzle 8 according to the invention (FIGS. 1, 2) has an aerosol generating device 55 for producing an aerosol from the liquid or dry, free-flowing injection material and conveying air and an aerosol injection device 56 for injecting the aerosol, in particular centrally, into the interior of a dry mixture existing dry material flow on. An aerosol is a heterogeneous mixture of solid and / or liquid suspended particles in a gas.

The mixing nozzle 8 also has a nozzle housing 13 and a nozzle longitudinal axis 14. Furthermore, the mixing nozzle 8 has a nozzle inlet end 8a and a nozzle outlet end 8b opposite this in the direction of the nozzle longitudinal axis 14. In addition, the mixing nozzle 8 has a flow or conveying channel 15 extending in the direction of the nozzle longitudinal axis 14 through the mixing nozzle 8. The delivery passage 15 extends from the nozzle inlet end 8a to the nozzle outlet end 8b through the mixing nozzle 8.

A main conveying direction 18 of the mixing nozzle 8 is parallel to the nozzle longitudinal axis 14 and extends from the nozzle inlet end 8a to the nozzle outlet end 8b.

The nozzle housing 13 also has a Gehäuseumfangs- or outer wall 16, which surrounds the flow or conveying channel 15. The housing wall 16 is preferably made of metal or ceramic or plastic. Preferably, the mixing nozzle 8 also consists of several, in particular four housing parts 13a to 13d, which are firmly connected to each other, in particular screwed. Within the scope of the invention it is also the case that the housing part 13b is omitted and the housing parts 13a and 13c are placed directly against each other, which will be discussed in more detail below.

The nozzle inlet end 8a of the mixing nozzle 8 according to the invention serves to connect the first air conveying line 3a. As a result, the mixing nozzle 8 according to the invention at the nozzle inlet end 8a per se known means for gas-tight connection of the first air conveyor line 3a. These means are, for example, a known coupling with a rubber seal, in particular a quick-release coupling. In addition, the mixing nozzle 8 at the nozzle inlet end 8a has an air chamber 17 open toward the nozzle inlet end 8a. The air chamber 17 preferably has a circular cylindrical cross section. In addition, it is arranged with its air chamber axis in particular coaxially to the nozzle longitudinal axis 14.

Adjoining the air chamber 17, in the main conveying direction 18, is a partition wall 19. The dividing wall 19 separates the air chamber 17 from a first mixing chamber or aerosol chamber 20. The dividing wall 19 thus cuts through the conveying channel 15. It is preferably perpendicular to the main conveying direction 18 or to the nozzle longitudinal axis 14. The dividing wall 19 has an inlet-side dividing wall surface and an outlet end Partition wall surface. The two partition wall surfaces are preferably perpendicular to the nozzle longitudinal axis 14 or to the main conveying direction 18.

In addition, the partition wall 19 a plurality, in particular circular cylindrical, air passageways 21, which extend in the main conveying direction 18 through the partition wall 19 through. The air passageways 21, seen in the circumferential direction with respect to the longitudinal axis of the nozzle 14, are arranged distributed around the nozzle longitudinal axis 14 and are spaced from the nozzle longitudinal axis 14. In this case, the air passage channels 21 preferably all have the same distance from the nozzle longitudinal axis 14. Preferably, 5 to 20 air passageways 21 are present. The air passageways 21 are also preferably all equally spaced in the circumferential direction. The partition 19 also has an injection material supply passage 22 for supplying the injection material into the aerosol chamber 20. The injection material supply channel 22 has a first, in particular circular cylindrical, supply channel section 23 and an adjoining second, in particular circular cylindrical, supply channel section 24. The first feed channel section 23 extends, in particular perpendicular to the nozzle longitudinal axis 14 or main conveying direction 18, into the housing outer wall 16 and the dividing wall 19 from the outside. A channel axis of the first feed channel 23 is thus preferably perpendicular to the nozzle longitudinal axis 14 and main conveying direction 18 and extends radially with respect to the nozzle longitudinal axis 14. The second Zuführkanalabschnitt 24 also has a channel axis, which, however, extends parallel to the nozzle longitudinal axis 14 and main conveying direction 18. In particular, the channel axis is coaxial with the nozzle longitudinal axis 14. As a result, the injection material supply channel 22 has a bend at which the first and second supply channel sections 23, 24 merge into one another. The second feed channel section 24 also opens into the aerosol chamber 20. At the free end of the second feed channel section 24, a sputtering nozzle 25 (shown schematically) is arranged in the second feed channel section 24. The atomizing nozzle 25 is used for atomizing the injection material into the aerosol chamber 20. The atomizing nozzle 25 is in particular a flat jet nozzle, smooth jet nozzle, hollow cone nozzle, full cone nozzle or mist nozzle (in the case of the injection liquid) or a sandblasting nozzle or jet nozzle for free flowing bulk materials (in the US Pat Case of dry injection mate- neck).

The first Zuführkanalabschnitt 23 opens, as already explained, outward to the environment. As a result, the first supply channel section 23 has means for connecting the injection material delivery line 5, in particular an internal thread 26. The aerosol chamber 20 has a chamber wall 27 surrounding the aerosol chamber 20. Viewed in the main conveying direction 18, the cam- merumfangswandung 27 initially a circular cylindrical wall portion 27a, which is followed by another circular cylindrical wall portion 27b, the diameter of which is larger than the diameter of the first wall portion 27a. Connected to the second circular-cylindrical wall section 27b is a conical wall section 27c, which, viewed in the main conveying direction 18, that is to say from the nozzle inlet end 8a to the nozzle outlet end 8b, tapers. The aerosol chamber 20 in this case has a chamber central axis 28, which is preferably coaxial with the nozzle longitudinal axis 14. The second cylindrical wall section 27b serves in particular to save material and can also be dispensed with, so that the first cylindrical wall section 27a merges directly into the conical wall section 27c. If the housing part 13b is omitted, the conical wall section 27c is omitted. In the simplest case, the comb-peripheral wall 27 is of continuous cylindrical design. The aerosol chamber 20 is adjoined in the main conveying direction 18 by a connecting channel 29, in particular a circular-cylindrical one. A channel axis of the connecting channel 29 is also preferably coaxial with the nozzle longitudinal axis 14. The connecting channel 29 opens into a second mixing chamber or swirl chamber 30. The connecting channel 29 also has an internal thread 31, which serves for screwing in an injection tube 32.

The injection tube 32 (Figures 2, 8 and 9) has an inlet-side tube end 32a and an outlet-side tube end 32b. The injection tube 32 is preferably made of metal or ceramic. In addition, the injection tube 32 has a tube longitudinal axis 33, which is preferably also coaxial with the nozzle longitudinal axis 14. A tube wall 34 of the injection tube 32 has a tube wall outer surface 34a and tube wall inner surface 34b. The tube wall inner surface 34b is of continuous circular cylindrical shape and surrounds a tube flow channel or tube conveying channel 35, which extends from the inlet-side tube end 32a to the outlet-side tube end 32b through the injection tube 32. The pipe wall outer surface 34a, viewed in the main conveying direction 18, initially has an external thread 36. To the outside Thread 36 is followed by a radially projecting from the pipe wall outer surface 34 a annular collar 37. The circular collar 37 is adjoined by a circular-cylindrical surface section 38, which in turn is adjoined by a conical surface section 39. The conical surface portion 39 tapers seen in the main conveying direction 18. It is also arranged on the outlet side pipe end 32b.

The vortex chamber 30 has a chamber peripheral wall 40 and a chamber center axis 41, which is coaxial with the nozzle longitudinal axis 14. The chamber perimeter wall 40 of the vortex chamber 30, seen in the main conveying direction 18, has a cylindrical wall section 40a and an adjoining conical wall section 40b. The conical wall section 40b tapers in the main conveying direction 18, that is to say seen from the nozzle inlet end 8a to the nozzle outlet end 8b.

The vortex chamber 30 opens into an outlet channel 42 with a preferably circular-cylindrical cross-section. The outlet channel 42 opens to the environment. A channel axis of the outlet channel 42 is preferably coaxial with the nozzle longitudinal axis 14.

The injection tube 32 is screwed with its external thread 36 into the internal thread 31 of the connecting channel 29 so far that a part of the injection tube 32 projects into the swirl chamber 30 inside. In particular, the region of the injection tube 32 projects with the circular-cylindrical and the conical surface section 38; 39 into the vortex chamber 30 inside. Respectively. a part of the injection tube 32 having the outlet-side tube end 32b of the injection tube 32 protrudes into the vortex chamber 30. The injection tube 32 is in this case spaced from the chamber peripheral wall 40, so that a flow cross-section is formed therebetween.

The nozzle housing 13 also has a connecting piece 43, which serves to connect the dry mixture reservoir 6. The connecting piece 43 is radially outside of the housing peripheral wall 16 from. In addition, the connecting piece 43 has a, preferably cylindrical, dry mixed inlet channel 44 on. A channel axis 44a of the dry mixture inlet channel 44 extends radially to the nozzle longitudinal axis 14. However, the channel axis 44a can also be arranged at an angle to the nozzle longitudinal axis 14. Preferably, the angle (Fig. 1) is 30 to 90 °. In particular, it is 90 °. The dry mixture inlet channel 44 may of course also have a bent or bent course. The angular ranges specified above then apply to the mouth region in which the dry mixture inlet channel 44 opens into the vortex chamber 30.

Furthermore, the dry mixture inlet channel 44 extends through the housing peripheral wall 16 and opens into the swirl chamber 30. Here, the dry mixture inlet channel 44 is arranged so that it in the radial direction with respect to the nozzle longitudinal axis 14 in alignment with the projecting into the swirl chamber 30 in Injection tube 32 is arranged. Preferably, the dry mixture inlet channel 44 is arranged in the radial direction in alignment with the circular cylindrical surface section 38 of the injection tube 32. The dry mixture inlet channel 44 is thus arranged at the inlet end of the vortex chamber 30. Respectively. the dry mixture inlet channel 44 is arranged at the rear end of the vortex chamber 30 in the main conveying direction 18. Respectively. the dry mixture inlet channel 44 is arranged in the region of the cylindrical wall section 40a of the vortex chamber 30.

The mixing nozzle 8 according to the invention also preferably has an additional bypass air inlet channel 45 for the possible additional supply of bypass air. The air inlet channel 45 has a first inlet channel section 46 opening out to the surroundings and a second inlet channel section 47 adjoining it. The first inlet channel section 46 extends, in particular perpendicular to the nozzle longitudinal axis 14, through a further connecting piece 48 through and into the housing wall 16. A channel axis of the first inlet channel section 46 thus extends radially with respect to the nozzle longitudinal axis 14. The second inlet channel section 47 has a channel axis which extends parallel to the nozzle longitudinal axis 14. The channel axis may also be slightly inclined to the nozzle longitudinal axis 14 and include an angle <90 ° with this. As a result, the air intake passage 45 has a bend at which the first and second intake passage portions 46; 47 merge into each other. The channel axis of the second inlet channel section 47 is, however, spaced from the nozzle longitudinal axis 14. The second inlet channel section 47 opens into the swirl chamber 30 at the inlet end of the swirl chamber 30. In addition, the second inlet channel section 47 is seen in a view perpendicular to the nozzle longitudinal axis 14, preferably radially opposite to Dry mixture inlet channel 44 arranged. The bypass air inlet channel 45 serves to connect a preferably existing bypass air delivery line 3 c, which is in communication with the compressed air source 2. Alternatively, an additional compressed air source may be present.

In this case, the entire compressed air supply of the shotcrete application device 1 is set up so that the mixing nozzle 8 is operated at the same pressure level as the rest of the injection molding machine 7. If the pressure in the mixing nozzle 8 is too high, the air would flow back into the machine 7. Conversely, the material mixture would be pressed into the injection tube 32 and the mixing nozzle 8 would be closed. The shotcrete application method according to the invention using the shotcrete application device 1 according to the invention will now be explained below.

At the nozzle inlet end 8a, conveying air is fed from the compressed air source 2 through the first air conveying pipe 3a into the air chamber 17 of the mixing nozzle 8. The conveying air flows from the air chamber 17 through the air passageways 21 in the main conveying direction 18 into the aerosol chamber 20.

Furthermore, the injection material from the injection material reservoir 4, for example by means of the injection material feed pump 50, which is preferably a compressed air operated double membrane ran pump transported through the injection material delivery line 5 and the injection material supply channel 22 into the aerosol chamber 20.

The injection material is, as already explained, injected through the atomizing nozzle 25 into the aerosol chamber 20. In this case, the injection material, also due to the simultaneously flowing at high speed into the aerosol chamber 20 into the conveying air, zer and dusted and mixed with the conveying air, so that the aerosol forms. The injection material is thereby introduced into the interior of the conveying air flow, in particular centrally in the conveying air flow. A nozzle longitudinal axis of the atomizing nozzle 25 is parallel to the main conveying direction 18.

The aerosol chamber 20, the air passageways 21, the injection material supply channel 22 and the atomizing nozzle 25 arranged at the end of the injection material supply channel 22 are part of the aerosol generating device 55 of the mixing nozzle 8. The aerosol formed flows out of the aerosol chamber 20 into the connecting channel 29 in the main conveying direction 18 and through the pipe flow passage 35 into the swirl chamber 30. Since the injection tube 32 projects far into the vortex chamber 30, the aerosol flows into the vortex chamber 30 at the outlet end. In addition to the aerosol, the dry mixture is also fed into the swirl chamber 30.

The dry mix flows through the dry mix inlet channel 44 into the swirl chamber 30. The dry mixture thus flows in the radial direction with respect to the nozzle longitudinal axis 14 into the vortex chamber 30. Since the dry mixture inlet channel 44 is arranged at the inlet end of the vortex chamber 30 and the injection tube 32 protrudes into the vortex chamber 30, the dry material flow from the dry mixture as it flows into the vortex chamber 30 strikes the outer wall surface 34a of the tube, in particular the circular cylindrical surface section 38 , of the injection tube 32th Thus the dry material stream is divided and optimally swirled and distributed in the swirl chamber 30.

Due to the higher flow velocity in the injection tube 32, the dry mixture is automatically sucked into the vortex chamber 30 in relation to the material flow of the dry mixture (venturi effect) and mixed there with the injection material. The Venturi effect results in particular from the tapering of the conical wall section 40b of the chamber peripheral wall 40 of the vortex chamber 30. For this causes an acceleration of the material and a suction effect. If the injection material is an injection liquid, the dry mixture is also advantageously prewetted in the aerosol chamber 20. Preferably, the pre-wetted material mixture has a moisture content of 0.2 to 7.0 wt .-%, preferably from 0.2 to 5.0 wt .-%, particularly preferably from 0.2 to 2.0 wt .-% based on the dry matter on. In the vortex chamber 30, the injection of the aerosol according to the invention takes place centrally in the material flow of the dry mixture, since the injection tube 32 projects into the vortex chamber 30. Respectively. The aerosol is injected from the inside into the dry material stream. Respectively. it is injected into the interior of the dry material stream. The injection direction is parallel to the main conveying direction 18. This has the advantage that the, preferably moist, aerosol does not get into the dry mixture conveying line 7. Clogging and sticking of the dry mixture delivery line 7 is thereby prevented.

The vortex chamber 30, the dry mixture inlet channel 44 opening into the vortex chamber 30 and the injection tube 32 protruding into the vortex chamber 30 and in fluid communication with the aerosol chamber 20 are thus part of the aerosol injection device 56 of the mixing nozzle 8 according to the invention.

As already explained, additional compressed air can also be introduced into the vortex chamber 30 via the bypass air feed line 3c through the bypass air inlet channel 30 be introduced. This reduces the deposition of the material on the chamber peripheral wall 40 of the vortex chamber 30. The additional air supply at the same time for even greater turbulence of the material mixture in the vortex chamber 30. The resulting, preferably pre-wetted, material mixture is then through the outlet channel 42 of the mixing nozzle 8 in the Promoted hose 9 and mixed at the injection nozzle end of the hose 9 in or just before the spray nozzle 10 with the liquid to the finished, to be applied concrete spraying compound. The finished injection molding compound preferably has a moisture content of 6.0 to 12.0% by weight (dense concrete) or from 20.0 to 40.0% by weight (lightweight concrete), based in each case on the dry mass. The liquid is added, for example, via a water ring known per se or a ring-gap nozzle known per se. The spray mass is then applied by the respective operator with the spray nozzle 10 on the respective surface. The surface to be coated is, in particular, mineral substrates, preferably masonry or refractory substrates or rocks or insulating materials, or steel armor, which may each be equipped with ceramic or metallic anchoring systems. Advantage of the invention is that the composition of the spray mass and in particular the rheology of the spray mass and their reactivity on the variation of the compositions of the injection material, the liquid and the dry mixture are flexibly adjustable. Because the conveying air, the liquid, the dry mixture and the injection material are fed individually and from individual, separate, reservoirs of the mixing nozzle. The composition of the injection material and of the dry mixture and of the liquid, in particular of the liquid binder, can thus be changed independently of one another.

If the concrete additives or additives are already contained in the, in particular liquid, injection material, they become in the aerosol and thereby in the dry mixture very finely and homogeneously distributed, resulting in improved strength properties of fresh concrete and hardened hardened concrete.

The same applies to the other constituents of the injection material, in particular the sintering aids. In particular, with the injection material, whether liquid or dry, very fine, pulverulent substances can generally be added, which can only be added poorly via the dry mixture. Because of its low bulk density, the fine constituents are very difficult to mix homogeneously into the dry mixture. In addition, in the production of the dry mixture there is the risk that the fine constituents are again removed in an uncontrolled manner from the dry mixture by various dust extraction during mixing, by conveying and sagging of the dry mixture, in relation to the other components of the dry mixture.

If the dry mixture contains no binder and no setting additive, it is advantageous that the dry mixture in principle has an unlimited storage time, since binders and reactants are stored separately from each other and thus can not prematurely react with each other. Because of this, no reactions take place even at higher air humidity, so that no performance losses occur even with a long storage time. Also, the dry mixture, if it contains no additives and no binder, harmless to health and therefore free of labeling. In addition, concrete additives are not storage stable, which would also limit the shelf life of the dry mix. The nozzle guide, which operates the spray nozzle, also has no additional burden due to additional equipment or handling. Because the pre-wetting takes place in the mixing nozzle, ie before the hose line, which leads to the spray nozzle. The spray nozzle itself is not modified and therefore uncomplicated and as usual handlebar. It is also advantageous that the injection tube is replaceable, since it is heavily loaded abrasive.

The injection of the aerosol into the interior of the dry material stream is particularly advantageous because, in contrast to a mixing supplied radially from the outside (eg via a water ring), no material sticking, settling or blocking of the delivery hose ("stopper") is formed Injection of the predefined aerosol centrally from the inside, in the case of the liquid injection material, results in immediate wetting of the dry material. without the inside of the hose coming into direct contact with the aerosol.

In the context of the invention, it is also the case that the injection tube 32 projects out of the nozzle housing 13 at the nozzle outlet end 8b (not shown). Respectively. the outlet-side pipe end 32b of the injection pipe 32 projects out of the nozzle housing 13. In this embodiment, too, it is ensured that the aerosol is always, in particular centrally, injected into the interior of the dry material flow. The injection direction is also parallel to the main conveying direction 18. The mixing of the aerosol with the dry mixture then takes place outside the mixing nozzle 8, in particular within the hose 9. If necessary, the flow cross sections must be adjusted accordingly so that the grains of the dry mixture can flow through the mixing nozzle 8 unhindered. Preferably, the flow cross-section for the areas of the mixing nozzle 8 through which the stream of dry material flows corresponds to at least 3 times the maximum grain size. This of course applies to any embodiments.

It is also within the scope of the invention that the mixing nozzle 8 is arranged in the hose line 9. Preferably, however, it is part of the injection molding machine 7 and arranged at the outlet of the injection molding machine 7. Another advantage of the invention is the pre-wetting of the dry mixture with the liquid injection material, which is only possible by the mixing nozzle according to the invention. The pre-wetted dry material is wetted much better at the spray nozzle by the liquid binder and mixed, such as a dust-dry material. This leads to lower rebound values and reduced dust formation.

Surprisingly, it was also found in the context of the invention that in a pre-wetting and the strength of the fired Feuerbetons could be improved. Due to the pre-wetting, the refractory fine components of the dry mixture appear to be better digested. An envelope forms around the refractory fine particles, resulting in improved formation of the ceramic binder phase of the fire concrete.

Increases in strength in relation to powdered additives introduced via the dry mixture were found. The advantages mentioned are demonstrated by the following exemplary embodiments:

Three materials, completely different from their material concept, were used for test purposes:

^■ REFRAJET Nanobond F-58 R

A cement-free dry sprayed concrete based on a CO-resistant fireclay. A typical application is the repair of blast furnace shafts (cold repair and hot repair by robot).

^■ REFRAJET Nanobond S-60

A cement-free dry sprayed concrete based on silicon carbide. Typical applications are waste incineration plants.

REFRAJET Nanobond C-84 AL: A cement-free dry sprayed concrete based on corundum (WFA) with a special anti-wetting system for the aluminum industry. Typical field of application is the bath area of aluminum melting furnaces (cold repair and hot repair). A total of 6 x 2000 Kg dry matter was available for experimental purposes. From the three above-mentioned recipes each spray panels were produced. This was done in each case both by the method according to WO 2010/105049 A2 (SdT) and by the method with pre-wetting.

In the process according to WO 2010/105049 A2, corresponding curing additives were already mixed in during the production of the dry material. For spraying, a commercial dry spray device (type: Meyco Piccola 020 E, small rotor 12x round hole, 1st gear, hose length: 20 m, delivery pressure approx. 3.5 bar) was used. At the end of the conveyor tube, the liquid binder (silica sol) was injected via a water ring at a pressure of approximately 20 bar in each case.

In the method with the mixing nozzle according to the invention, the above-mentioned dry spray device was also used. However, the mixing nozzle according to the invention was additionally used. This was connected to the beginning of the conveyor tube. The drying material was mixed with no Abbindeadditive during production. The dry mix thus contained no reactive substances. At the end of the Forderschlauchs again the liquid binder (silica sol) was injected via the water ring.

It was found that all three product types could be sprayed, however, significant differences in the installation quality of the two variants (SdT / with the mixing nozzle according to the invention) could already be recognized during the test procedure:

In direct comparison, the system with the mixing nozzle according to the invention showed a significantly lower dust formation when applying the material to the bulkhead / ceiling. This positive feature can be attributed to the pre-wetting of the dust-dry material, which can then be wetted much easier and more intense at the water ring of the spray nozzle and thus exerts less dust.

In direct comparison, the system with the mixing nozzle according to the invention showed a significantly lower rebound when applying the material to the bulkhead / ceiling. This positive property feature can be attributed to the pre-wetting of the dust-dry material, which can then be wetted much easier and more intense at the water ring of the spray nozzle. The fines contained in the dry mix do not escape as dust, but help to form a homogeneous material bed on the wall / ceiling, which significantly reduces rebound.

The sprayed over the mixing nozzle according to the invention material is evidently more reactive and solidifies at the bulkhead / ceiling much faster. This leads to a faster work progress, since even larger wall thicknesses can be applied in a single operation.

In order to determine the physical characteristics of the product, spraying panels were also made (300x300x150 mm), which were switched off after 24 h and treated further. Already during stripping, a higher mechanical stripping strength could be determined for all three material qualities consistent with the spraying panels produced with the mixing nozzle according to the invention, whereas the samples squirted by the method according to the prior art were still relatively crumbly and had to be treated with appropriate care. After stripping, the material samples (300x300x150 mm) were dried at 1 10 ° C / 24 h and then sawed by diamond saw test specimen in size B (230x64x54 mm) according to DIN EN 1927-5 (March 2013), according to the respective on the X -Axis of Fig. 10-15 pre-fired and evaluated with a holding time of 5h each specified test temperatures. The cold pressure and bending strengths were determined in accordance with DIN EN 1927-6 (March 2013). The significant increases in strength can be clearly seen in FIGS. 10-15:

In the case of all three types of materials available for test purposes, it was possible to determine better characteristic features of the variants sprayed with the mixing nozzle according to the invention over the entire temperature profile.

Claims

claims

Mixing nozzle (8) for a shotcrete application device (1) for dry spraying of concrete, in particular of refractory concrete, comprising a) an aerosol generating device (55) for producing an aerosol from a liquid or dry, free-flowing injection material and conveying air,

b) an aerosol injection device (56) for injecting the aerosol, in particular centrally, into the interior of a dry material stream consisting of a dry mixture.

Mixing nozzle (8) according to claim 1,

characterized in that

the aerosol generating device (55) comprises:

a) an aerosol chamber (20),

b) at least one air passage channel (21) opening into the aerosol chamber (20) for feeding the conveying air into the aerosol chamber (20), in particular into a main conveying direction (18), c) at least one injection material feed channel (22) opening into the aerosol chamber (20) for feeding the injection material into the aerosol chamber (20),

d) an atomizing nozzle (25) arranged at the end of the injection material supply channel (22) for the atomising injection of the injection material into the conveying air flow in the aerosol chamber (20).

Mixing nozzle (8) according to claim 1 or 2,

characterized in that

the aerosol injection device (56) comprises:

a) a vortex chamber (30), b) a dry mixture inlet channel (44) opening into the vortex chamber (30) for feeding the dry mixture into the vortex chamber (30),

c) an injection tube (32) protruding into the vortex chamber (30) and in fluid communication with the aerosol chamber (20) for supplying the aerosol into the interior of the dry material stream.

Mixing nozzle (8) according to claim 3,

characterized in that

the injection tube (32) is arranged so that the dry material flow emerging from the dry mixture inlet channel (44) meets the injection tube (32) and is thereby divided.

Mixing nozzle (8) according to claim 4,

characterized in that

the injection tube (32) is arranged to divide the dry material stream before the aerosol is injected into the dry material stream.

Mixing nozzle (8) according to one of claims 2 to 5,

characterized in that

the injection tube (32) is arranged to inject the aerosol into the dry material stream within the vortex chamber (30).

Mixing nozzle (8) according to one of claims 2 to 5,

characterized in that

the injection tube (32) is arranged such that injection of the aerosol into the dry material stream occurs outside the vortex chamber (30).

8. mixing nozzle (8) according to one of claims 2 to 7,

characterized in that

the aerosol generating means (55) is formed, in particular the air passageways (21), the injection material supply channel (22) and the atomizing nozzle (25) are arranged and formed so that the injection of the injection material, preferably centrally, takes place in the interior of the conveying air flow ,

Mixing nozzle (8) according to one of claims 2 to 8,

characterized in that

the mixing nozzle (8) has a nozzle longitudinal axis (14) and a nozzle inlet end (8a) and a nozzle outlet end (8b) opposite the same in the direction of the nozzle longitudinal axis (14) and a flow extending in the direction of the nozzle longitudinal axis (14) through the mixing nozzle (8) or conveying channel (15), wherein a main conveying direction (18) of the mixing nozzle (8) extending from the nozzle inlet end (8a) to the nozzle outlet end (8b) is preferably parallel to the nozzle longitudinal axis (14).

Mixing nozzle (8) according to one of claims 2 to 9,

characterized in that

the mixing nozzle (8) has a dividing wall (19) which has the at least one air passage channel (21), preferably several, in particular circular cylindrical, air passage channels (21) which, in particular into the main conveying direction (18), pass through the dividing wall (19). extend through and into the aerosol chamber (20) open.

Mixing nozzle (8) according to claim 10,

characterized in that

the air passage channels (21) in the circumferential direction with respect to the nozzle longitudinal axis (14), arranged distributed around the nozzle longitudinal axis (14) and from the nozzle longitudinal axis (14), wherein in the case of the air passage channels (21), they preferably all have the same distance from the nozzle longitudinal axis (14) and are preferably all equally spaced from one another in the circumferential direction.

Mixing nozzle (8) according to claim 10 or 11,

characterized in that

the partition wall (19) has the injection material supply channel (22) for feeding the injection material into the aerosol chamber (20), the injection material supply channel (22) having a feed channel section (24) opening into the aerosol chamber (20), in particular circular cylindrical wherein the second feed channel section (24) has a channel axis which preferably extends parallel, preferably coaxially, to the nozzle longitudinal axis (14).

Mixing nozzle (8) according to one of claims 2 to 12,

characterized in that

the atomizing nozzle (25) is a flat jet nozzle, smooth jet nozzle, hollow cone nozzle, full cone nozzle or mist nozzle or a sandblasting nozzle or jet nozzle for pourable bulk materials.

14. mixing nozzle (8) according to one of claims 3 to 13,

characterized in that

the aerosol chamber (20) is in fluid communication with the vortex chamber (30) via the injection tube (32).

Mixing nozzle (8) according to one of claims 3 to 14,

characterized in that

the vortex chamber (30) has a chamber peripheral wall (40) and a chamber central axis (41) which is coaxial with the longitudinal axis of the nozzle (14), the chamber peripheral wall (40) preferably having a conical wall section (40b) extending in main Conveying direction (18) seen such that the dry mixture is sucked into the vortex chamber (30) by the Venturi effect.

Mixing nozzle (8) according to claim 15,

characterized in that

the injection tube (32) is spaced from the chamber perimeter wall (40) to form a flow area therebetween.

Mixing nozzle (8) according to one of claims 3 to 16,

characterized in that

the dry mix inlet channel (44) has a channel axis (44a) which opens into the swirl chamber (30) in an area where the dry mix inlet channel (44) opens at an angle of 30 to 90 °, preferably 90 ° Includes nozzle longitudinal axis (14).

Mixing nozzle (8) according to one of claims 3 to 17,

characterized in that

the mixing nozzle (8) has a bypass air inlet channel (45) for supplying bypass air into the vortex chamber (30), the bypass air inlet channel (45) having an inlet channel section (47) opening into the vortex chamber (30), preferably at one inlet-side end of the vortex chamber (30) opens into this and

wherein preferably a channel axis of the inlet channel section (47) is parallel to the nozzle longitudinal axis (14) or inclined to the nozzle longitudinal axis (14) and encloses an angle <90 ° therewith,

and / or wherein preferably the channel axis of the inlet channel section (47) is spaced from the nozzle longitudinal axis (14).

19. mixing nozzle (8) according to claim 18,

characterized in that the second inlet channel section (47) is arranged in a view perpendicular to the longitudinal axis of the nozzle (14) and radially opposite to the dry mixture inlet channel (44).

20. shotcrete application device (1) for spraying a spray mass, in particular a Feuerbetonspritzmasse, having on a surface:

a) a compressed air source (2) for providing conveying air,

b) an injection material reservoir (4) filled with a dry or liquid injection material, in particular an injection liquid,

c) a dry mixture reservoir (6) filled with a dry mixture,

d) a mixing nozzle (8) according to one of the preceding claims for mixing the injection material with the conveying air and the dry mixture to form a, in particular pre-wetted, material mixture,

e) a spray nozzle (10) for spraying the sprayed material onto the surface to be coated,

f) a line (9) connected to the mixing nozzle (8) for conveying the material mixture to the spray nozzle (10),

g) a liquid storage container (1 1) filled with a liquid, in particular a liquid binder,

h) means for mixing the, in particular pre-wetted, material mixture with the liquid to the spray mass at the injection nozzle side end of the hose line (9) before or in the spray nozzle (10).

21. Shotcrete application device (1) according to claim 20,

characterized in that

the mixing nozzle (8) is arranged at an inlet-side end of the hose line (9).

22. Dry spray method for spraying a spray mass, in particular a Feuerbetonspritzmasse, on a surface, preferably with a shotcrete application device (1) according to claim 20 or 21 with the following process steps:

a) mixing a dry or liquid injection material, in particular an injection liquid, with conveying air to form an aerosol,

b) injecting the aerosol, in particular centrally, into the interior of a dry material stream consisting of a dry mixture and mixing the aerosol with the dry mixture to form a material mixture,

c) conveying the material mixture by means of a hose line (9) to a spray nozzle (10),

d) mixing the material mixture at the injection nozzle end of the hose line (9) in or in front of the spray nozzle (10) with a liquid to the injection molding compound,

e) applying the spray mass to the surface to be coated by means of the spray nozzle (10).