CA2626090A1 - Mixing device and method for adding an additive to a pumpable mixture - Google Patents
Mixing device and method for adding an additive to a pumpable mixture Download PDFInfo
- Publication number
- CA2626090A1 CA2626090A1 CA002626090A CA2626090A CA2626090A1 CA 2626090 A1 CA2626090 A1 CA 2626090A1 CA 002626090 A CA002626090 A CA 002626090A CA 2626090 A CA2626090 A CA 2626090A CA 2626090 A1 CA2626090 A1 CA 2626090A1
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- Prior art keywords
- mixing device
- additive
- metering
- mixture
- concrete
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28C5/00—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions
- B28C5/02—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions without using driven mechanical means effecting the mixing
- B28C5/06—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions without using driven mechanical means effecting the mixing the mixing being effected by the action of a fluid
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
- B01F25/30—Injector mixers
- B01F25/31—Injector mixers in conduits or tubes through which the main component flows
- B01F25/313—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit
- B01F25/3132—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit by using two or more injector devices
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
- B01F25/30—Injector mixers
- B01F25/31—Injector mixers in conduits or tubes through which the main component flows
- B01F25/313—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit
- B01F25/3133—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit characterised by the specific design of the injector
- B01F25/31331—Perforated, multi-opening, with a plurality of holes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
- B01F25/40—Static mixers
- B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
- B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
- B01F25/433—Mixing tubes wherein the shape of the tube influences the mixing, e.g. mixing tubes with varying cross-section or provided with inwardly extending profiles
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F2101/00—Mixing characterised by the nature of the mixed materials or by the application field
- B01F2101/28—Mixing cement, mortar, clay, plaster or concrete ingredients
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Dispersion Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Structural Engineering (AREA)
- Preparation Of Clay, And Manufacture Of Mixtures Containing Clay Or Cement (AREA)
Abstract
In a mixing device (6) for metering an additive into a pumpable mixture (10) with plastic-viscous behaviour, in particular concrete, the mixture is transported in a line (4). The mixing device comprises, in the direction of flow of the mixture (10), a diffusor element (8) and a confusor element (11).
Arranged in the interior of the mixing device is at least one metering device (12, 17, 18, 22) with at least one metering location (13), by means of which additive (5) is added into the mixture (10).
Arranged in the interior of the mixing device is at least one metering device (12, 17, 18, 22) with at least one metering location (13), by means of which additive (5) is added into the mixture (10).
Description
Mixing device and method for adding an additive to a pumpable mixture Technical field The invention is based on a mixing device according to the precharacterizing clause of the first claim.
The invention is likewise based on a method for adding an additive to a pumpable mixture according to the precharacterizing clause of the independent method claim.
Prior art In many applications, small amounts of a substance, for example an additive, are admixed to a mixture with plastic-viscous behavior. However, thoroughly good mixing is frequently difficult to achieve. For example, to mix an additive, for example an activator, with fine mortar, use is made of conventionally known static mixers. If such known static mixers are also used with conventional concrete, the static mixer rapidly becomes blocked because of the coarse gravel fraction, and the mixer may even be destroyed.
The addition of the activator to the truck-mixed concrete and the mixing are therefore frequently already undertaken in the vehicle drum. The activator plasticizes the concrete and brings the setting mechanism into motion. A disadvantage is that, after the activator has been added to the concrete in the vehicle drum, not much more time must elapse before the activated concrete is used in the construction, since it otherwise already hardens beforehand.
Summary of the invention The invention is based on the object, in the case of a mixing device and a method of the type mentioned at the beginning, of providing a mixing device which makes it possible to rapidly and efficiently introduce additive to a plastic-viscous mixture.
This object is achieved according to the invention by the features of the first claim.
It is therefore the core of the invention that the mixing device comprises a diffuser element and a confusor element, and that at least one metering apparatus with at least one metering location, by means of which additive is added to the mixture, is arranged in the interior of the mixing device.
The advantages of the invention include the fact that the device shown here and the method are suitable in particular for the continuous addition and mixing of very small amounts of chemical additive to a pumpable mixture with plastic-viscous behavior, in particular to a granule-suspension mixture, such as concrete.
The invention therefore relates to a mixing apparatus for the continuous, homogeneous addition of very small amounts of chemical liquid additives to a pumpable granule-suspension mixture which has a plastic-viscous behavior, in particular wet concrete or truck-mixed concrete, such that said concrete can harden/set uniformly and in a defined manner, since, in particular in the case of concrete, an activator is used as the additive.
The practical difficulty of the realization in terms of apparatus of such a project resides in the homogeneous distribution of extremely small amounts of additive and in the blockage-free conveying, for example of the concrete, through the mixing apparatus. In more precise terms, there is both a general risk of blockage as the concrete flows around the metering elements and also as it flows from the cylindrical part of the mixing apparatus into the convergent part, and also local backflows in the mixing device and therefore nonuniform residence times, which results in different chemical reaction times in the granule-suspension mixture. The inert gravel fraction can be understood as meaning the granule, and fine sand, cement and water can be understood as meaning the suspension of the mixture fraction.
According to the invention, the additive is added via one or more metering apparatuses, for example helical coils, with the shape of the metering apparatus and a number of metering locations being designed and dimensioned in respect of a locally uniform and continuous distribution of the additive. This means, inter alia, that the flow of the granule-suspension mixture, for example of the concrete, is at the same time less obstructed, and therefore no blockage occurs.
Furthermore, the effect achieved by the high solids fraction of, for example, gravel in the ready-mixed concrete is that the liquid amount of additive which is metered in only passes into the suspension fraction of the concrete.
Further advantageous refinements of the invention emerge from the subclaims.
Brief description of the drawing Exemplary embodiments of the invention are explained in more detail below with reference to the drawings.
Identical elements are provided with the same reference numbers in the various figures. The direction of flow of the media is indicated by arrows.
In the drawings:
Figure 1 shows, schematically, the use of concrete in a construction;
The invention is likewise based on a method for adding an additive to a pumpable mixture according to the precharacterizing clause of the independent method claim.
Prior art In many applications, small amounts of a substance, for example an additive, are admixed to a mixture with plastic-viscous behavior. However, thoroughly good mixing is frequently difficult to achieve. For example, to mix an additive, for example an activator, with fine mortar, use is made of conventionally known static mixers. If such known static mixers are also used with conventional concrete, the static mixer rapidly becomes blocked because of the coarse gravel fraction, and the mixer may even be destroyed.
The addition of the activator to the truck-mixed concrete and the mixing are therefore frequently already undertaken in the vehicle drum. The activator plasticizes the concrete and brings the setting mechanism into motion. A disadvantage is that, after the activator has been added to the concrete in the vehicle drum, not much more time must elapse before the activated concrete is used in the construction, since it otherwise already hardens beforehand.
Summary of the invention The invention is based on the object, in the case of a mixing device and a method of the type mentioned at the beginning, of providing a mixing device which makes it possible to rapidly and efficiently introduce additive to a plastic-viscous mixture.
This object is achieved according to the invention by the features of the first claim.
It is therefore the core of the invention that the mixing device comprises a diffuser element and a confusor element, and that at least one metering apparatus with at least one metering location, by means of which additive is added to the mixture, is arranged in the interior of the mixing device.
The advantages of the invention include the fact that the device shown here and the method are suitable in particular for the continuous addition and mixing of very small amounts of chemical additive to a pumpable mixture with plastic-viscous behavior, in particular to a granule-suspension mixture, such as concrete.
The invention therefore relates to a mixing apparatus for the continuous, homogeneous addition of very small amounts of chemical liquid additives to a pumpable granule-suspension mixture which has a plastic-viscous behavior, in particular wet concrete or truck-mixed concrete, such that said concrete can harden/set uniformly and in a defined manner, since, in particular in the case of concrete, an activator is used as the additive.
The practical difficulty of the realization in terms of apparatus of such a project resides in the homogeneous distribution of extremely small amounts of additive and in the blockage-free conveying, for example of the concrete, through the mixing apparatus. In more precise terms, there is both a general risk of blockage as the concrete flows around the metering elements and also as it flows from the cylindrical part of the mixing apparatus into the convergent part, and also local backflows in the mixing device and therefore nonuniform residence times, which results in different chemical reaction times in the granule-suspension mixture. The inert gravel fraction can be understood as meaning the granule, and fine sand, cement and water can be understood as meaning the suspension of the mixture fraction.
According to the invention, the additive is added via one or more metering apparatuses, for example helical coils, with the shape of the metering apparatus and a number of metering locations being designed and dimensioned in respect of a locally uniform and continuous distribution of the additive. This means, inter alia, that the flow of the granule-suspension mixture, for example of the concrete, is at the same time less obstructed, and therefore no blockage occurs.
Furthermore, the effect achieved by the high solids fraction of, for example, gravel in the ready-mixed concrete is that the liquid amount of additive which is metered in only passes into the suspension fraction of the concrete.
Further advantageous refinements of the invention emerge from the subclaims.
Brief description of the drawing Exemplary embodiments of the invention are explained in more detail below with reference to the drawings.
Identical elements are provided with the same reference numbers in the various figures. The direction of flow of the media is indicated by arrows.
In the drawings:
Figure 1 shows, schematically, the use of concrete in a construction;
Figure 2 shows a schematic illustration of the outer shape of the mixing device according to the invention;
Figure 3 shows a schematic illustration of the outer shape of a further mixing device according to the invention;
Figure 4 shows a schematic illustration of the mixing device according to the invention according to figure 2 with a metering-in apparatus;
Figure 5 shows a schematic illustration of the mixing device according to the invention according to figure 2 with a further metering-in apparatus;
Figure 6 shows a schematic side view of the mixing device according to the invention according to figure 2 with a further metering-in apparatus;
Figure 7 shows a schematic top view along the axis of the metering-in apparatus;
Figure 8 shows a schematic top view along the axis of the metering-in apparatus in the mixing device with the granule-suspension mixture;
Figure 9 shows a schematic illustration of the metering-in operation;
Figure 10 shows a schematic illustration of a mixing device according to the invention with a further metering-in apparatus;
Figure 11 shows a schematic illustration of a mixing device according to the invention with a further metering-in apparatus;
Figure 12 shows a schematic illustration of the geometry of the confusor;
Figure 13 shows a schematic illustration of the geometry of the confusor;
Figure 14 shows a schematic illustration of the geometry of the diffuser.
Only the elements essential for directly understanding the invention are shown.
Figure 3 shows a schematic illustration of the outer shape of a further mixing device according to the invention;
Figure 4 shows a schematic illustration of the mixing device according to the invention according to figure 2 with a metering-in apparatus;
Figure 5 shows a schematic illustration of the mixing device according to the invention according to figure 2 with a further metering-in apparatus;
Figure 6 shows a schematic side view of the mixing device according to the invention according to figure 2 with a further metering-in apparatus;
Figure 7 shows a schematic top view along the axis of the metering-in apparatus;
Figure 8 shows a schematic top view along the axis of the metering-in apparatus in the mixing device with the granule-suspension mixture;
Figure 9 shows a schematic illustration of the metering-in operation;
Figure 10 shows a schematic illustration of a mixing device according to the invention with a further metering-in apparatus;
Figure 11 shows a schematic illustration of a mixing device according to the invention with a further metering-in apparatus;
Figure 12 shows a schematic illustration of the geometry of the confusor;
Figure 13 shows a schematic illustration of the geometry of the confusor;
Figure 14 shows a schematic illustration of the geometry of the diffuser.
Only the elements essential for directly understanding the invention are shown.
Way of implementing the invention Figure 1 illustrates, schematically, the use of a plastic-viscous mixture, here of concrete 10, in a construction. Concrete is delivered to the building site by means of a transport vehicle 1. The fact that the concrete is usually transported in a rotating drum mounted on the transport vehicle is not illustrated.
This concrete has been treated in the concrete factory with additives such that the hydration or setting mechanism is delayed by a number of hours. This concrete corresponds in general to a pumpable granule-suspension mixture with plastic-viscous behavior. The concrete 10 is temporarily stored in a container 2 or else is pumped directly from the vehicle to the building site under pressure by means of a pump 3 and a line 4. Such a line may be used for transporting the concrete over several hundred meters or even a few kilometers. Before the concrete 10 is used, the latter has to be reactivated for use by the addition of additives 5, such as activators, for example a setting accelerator. The addition of the additive takes place in a mixing device 6. Further substances, for example water, concrete from a different source, etc., can be supplied via a further line 7. The concrete 10' which is mixed with the additive 5 is then appropriately used at the building site at the use location 20. The concrete can be used in accordance with any desired methods, for example by means of spraying methods, casting methods, etc. The distance of the mixing device to the use location is as desired per se, but is advantageously selected to be as short as possible such that as little waste as possible occurs nor does activated concrete remain in the line and possibly make the latter unusable. With the present mixing device, it is also possible to fill the line from the mixing device to the use location with non-activated concrete 10 by no more activator being added to the mixing device. This prevents the line from becoming blocked.
By means of the mixing device shown here, it is permitted to meter in and mix small amounts of additive with the plastic-viscous mixture, in particular in a ratio of 1:100 to 1:1000.
Figures 2 and 3 illustrate the mixing device 6 schematically. Said mixing device comprises a diffuser element 8, a cylinder element 9 and a confusor element 11 in the direction of flow of the granule-suspension mixture. The cylinder element 9 may have any desired cross section, such as circular, oval, polygonal, etc., and the cross sections are in each case adapted to the particular requirements. The length of the cylinder element 9 is likewise adapted in each case to the particular conditions, such as amount of additive to be added, etc., and may, according to figure 2, be virtually zero. The diameter of the cross section remains essentially constant in the cylinder element.
The diffuser element is divergent and has an expansion angle a. The expansion angle a of the divergent part of the mixer apparatus is necessitated by the flow or depends on the permissible overall length of the mixing apparatus. A backflow may occur in the vicinity of the wall, see figure 14 in this respect, if the expansion angle is too large and/or the viscosity of the medium is too low. If the plastic-viscous flow of behavior of concrete in a cylindrical line with an apparent dynamic viscosity of ri = 30 Pa=s is described, then the classic fluid dynamics presupposes a backflow after an expansion angle a = approx. 60 , since Blasius's equation for the flow in a diffuser is:
Redy_35 dl 2 where dy/dl = tan((XG). The following applies for the expansion angle a:
This concrete has been treated in the concrete factory with additives such that the hydration or setting mechanism is delayed by a number of hours. This concrete corresponds in general to a pumpable granule-suspension mixture with plastic-viscous behavior. The concrete 10 is temporarily stored in a container 2 or else is pumped directly from the vehicle to the building site under pressure by means of a pump 3 and a line 4. Such a line may be used for transporting the concrete over several hundred meters or even a few kilometers. Before the concrete 10 is used, the latter has to be reactivated for use by the addition of additives 5, such as activators, for example a setting accelerator. The addition of the additive takes place in a mixing device 6. Further substances, for example water, concrete from a different source, etc., can be supplied via a further line 7. The concrete 10' which is mixed with the additive 5 is then appropriately used at the building site at the use location 20. The concrete can be used in accordance with any desired methods, for example by means of spraying methods, casting methods, etc. The distance of the mixing device to the use location is as desired per se, but is advantageously selected to be as short as possible such that as little waste as possible occurs nor does activated concrete remain in the line and possibly make the latter unusable. With the present mixing device, it is also possible to fill the line from the mixing device to the use location with non-activated concrete 10 by no more activator being added to the mixing device. This prevents the line from becoming blocked.
By means of the mixing device shown here, it is permitted to meter in and mix small amounts of additive with the plastic-viscous mixture, in particular in a ratio of 1:100 to 1:1000.
Figures 2 and 3 illustrate the mixing device 6 schematically. Said mixing device comprises a diffuser element 8, a cylinder element 9 and a confusor element 11 in the direction of flow of the granule-suspension mixture. The cylinder element 9 may have any desired cross section, such as circular, oval, polygonal, etc., and the cross sections are in each case adapted to the particular requirements. The length of the cylinder element 9 is likewise adapted in each case to the particular conditions, such as amount of additive to be added, etc., and may, according to figure 2, be virtually zero. The diameter of the cross section remains essentially constant in the cylinder element.
The diffuser element is divergent and has an expansion angle a. The expansion angle a of the divergent part of the mixer apparatus is necessitated by the flow or depends on the permissible overall length of the mixing apparatus. A backflow may occur in the vicinity of the wall, see figure 14 in this respect, if the expansion angle is too large and/or the viscosity of the medium is too low. If the plastic-viscous flow of behavior of concrete in a cylindrical line with an apparent dynamic viscosity of ri = 30 Pa=s is described, then the classic fluid dynamics presupposes a backflow after an expansion angle a = approx. 60 , since Blasius's equation for the flow in a diffuser is:
Redy_35 dl 2 where dy/dl = tan((XG). The following applies for the expansion angle a:
- if a>aG, then a backflow occurs.
- if a<aG, then no backflow occurs.
The expansion angle a of the diffuser is therefore preferably selected in a range of a = 10 to 60 , so that no backflow occurs. Of course, this angle may vary depending on the viscosity of the granule-suspension mixture used, it being essential that no backflow takes place.
The confusor element 11 is convergent and has a closing angle R. Experience shows that, in particular, a rapid reduction in diameter, i.e. a large angle R of concrete transport lines, leads to blockage. The angle R is preferably selected in a range of R= 5 to 20 .
There are essentially two types of outflow, the core flow and the mass flow. The two types of outflow are dependent on the closing angle, also called the cone angle, and the outlet diameter. For example, there is a core flow in a silo with a steep angle, i.e. the bulk material in the center flow outs while the bulk material at the wall temporarily remains stationary.
Such a behavior in the concrete line leads to a blockage, since, for reasons of continuity, the conveying by piston requires an outflow which is constant over the entire cross section, i.e., in the case of concrete, a flow velocity which is constant over the cross section.
In the case of a shallow angle, the mass flow occurs.
This flow is constant over the cross section. Faced with the requirement for a constant concrete flow velocity, this means that the mass flow is the desired flow form in the convergent part of the mixing apparatus. The angle R is therefore preferably selected in such a manner that a mass flow takes place.
- if a<aG, then no backflow occurs.
The expansion angle a of the diffuser is therefore preferably selected in a range of a = 10 to 60 , so that no backflow occurs. Of course, this angle may vary depending on the viscosity of the granule-suspension mixture used, it being essential that no backflow takes place.
The confusor element 11 is convergent and has a closing angle R. Experience shows that, in particular, a rapid reduction in diameter, i.e. a large angle R of concrete transport lines, leads to blockage. The angle R is preferably selected in a range of R= 5 to 20 .
There are essentially two types of outflow, the core flow and the mass flow. The two types of outflow are dependent on the closing angle, also called the cone angle, and the outlet diameter. For example, there is a core flow in a silo with a steep angle, i.e. the bulk material in the center flow outs while the bulk material at the wall temporarily remains stationary.
Such a behavior in the concrete line leads to a blockage, since, for reasons of continuity, the conveying by piston requires an outflow which is constant over the entire cross section, i.e., in the case of concrete, a flow velocity which is constant over the cross section.
In the case of a shallow angle, the mass flow occurs.
This flow is constant over the cross section. Faced with the requirement for a constant concrete flow velocity, this means that the mass flow is the desired flow form in the convergent part of the mixing apparatus. The angle R is therefore preferably selected in such a manner that a mass flow takes place.
There is a further risk of blockage due to bridging, see figure 12. The cone geometry defined in the mixing apparatus can now take place by means of criteria for eliminating bridging. Among the demands made by said criteria is that the angle 5 has to be > Y+gw because the solids bridge then slides along the wall, i.e.
cannot get stuck, and consequently no blockage occurs even in the case of plastic-viscous granule-suspension mixtures, such as ready-mixed and truck-mixed concrete.
This gives rise, according to the invention, to the angle y which defines the contour of the cone, see figures 12 and 13. The wall friction angle gW is in each case dependent on the material flowing through and on the wall. Also according to figure 13, the convergent part is advantageously defined by a convex and concave radius. The convergent part can be welded together, for example, from a dished head, basket head or any spherical head and a"trumpet-shaped" confusor.
Stress peaks may occur during the transition between the cylinder and cone. In the case of this mixing apparatus according to the invention for the continuous metering in of additive to the ready-mixed and truck-mixed concrete, the stress peak is prevented by specific, local-geometric design of the apparatus.
Depending on the concrete yield used, the diameter D is advantageously in a range of D = 0.2 m to 0.75 m, and the length 1 of the mixing device 6 is advantageously 1 = 0.8 m to 3 m.
The mixing device is in each case advantageously arranged in a line with the concrete line, and therefore it lies concentrically with respect to the concrete line. As a result, pipe bends, angled portions, etc. are no longer required, which saves on space. The mixing device can be installed both horizontally and vertically in the concrete conveying line.
cannot get stuck, and consequently no blockage occurs even in the case of plastic-viscous granule-suspension mixtures, such as ready-mixed and truck-mixed concrete.
This gives rise, according to the invention, to the angle y which defines the contour of the cone, see figures 12 and 13. The wall friction angle gW is in each case dependent on the material flowing through and on the wall. Also according to figure 13, the convergent part is advantageously defined by a convex and concave radius. The convergent part can be welded together, for example, from a dished head, basket head or any spherical head and a"trumpet-shaped" confusor.
Stress peaks may occur during the transition between the cylinder and cone. In the case of this mixing apparatus according to the invention for the continuous metering in of additive to the ready-mixed and truck-mixed concrete, the stress peak is prevented by specific, local-geometric design of the apparatus.
Depending on the concrete yield used, the diameter D is advantageously in a range of D = 0.2 m to 0.75 m, and the length 1 of the mixing device 6 is advantageously 1 = 0.8 m to 3 m.
The mixing device is in each case advantageously arranged in a line with the concrete line, and therefore it lies concentrically with respect to the concrete line. As a result, pipe bends, angled portions, etc. are no longer required, which saves on space. The mixing device can be installed both horizontally and vertically in the concrete conveying line.
Figure 4 illustrates the mixing device 6 with a metering apparatus 12. The metering apparatus 12 here is a helical coil on which are arranged a plurality of metering locations 13, which can also be referred to as injection locations. The metering locations 13 are advantageously arranged in the direction of flow of the mixture 10 such that the additive is metered in the direction of flow and the metering locations do not become blocked. The additive can be added via one or more of the metering apparatus 12, for example here the helical coils, with the shape of the metering elements and number of the metering locations 13 being designed and dimensioned with respect to a locally uniform and continuous distribution of the additive. This means, inter alia, that at the same time the flow of the granule-suspension mixture, for example of the concrete, is less obstructed, and therefore no blockage occurs. Furthermore, the effect achieved by the high solids fraction of, for example, gravel, in the ready-mixed concrete is that the liquid amount of additive metered in only passes into the suspension fraction of the concrete. Gravel particles are inert and if they are situated immediately in front of a local metering or injection location, they only deflect the additive jet, see figure 9 in this respect, and distribute the additive further.
The course 14 of the added additive through the mixer 6 is now explained by way of example by means of a metering location 13. After being metered into the granule-suspension mixture, the additive follows the mixture as a type of additive thread. These additive threads are illustrated as spots over the cross section at the location 15. The granule-suspension mixture then flows through the confusor 11 and, at the location 16, the additives are again illustrated as spots. It can clearly be seen that the additive threads lie very much closer together because of the narrowing than at the location 15 in the cylinder 9. Thoroughly good mixing of the additive into the granule-suspension mixture or the suspension fraction is thereby achieved. The number of metering locations is advantageously n = 100 to 300, the metering locations are at a distance 1 = 10 to 70 mm, and the diameter of the metering openings is d 0.4 to 1.5 mm.
Figures 5 and 6 illustrate the mixing device 6 with a metering apparatus 12 and 17 which here comprises a first helical coil 12 and a second helical coil 17.
Said helical coils are nested together in such a manner that a homogenous distribution of the metering locations 13 takes place in the projection in the metering locations over the cross sectional surface of the mixing apparatus, see figure 7 in this respect.
Figure 8 illustrates how often gravel particles can arrive at metering locations. Gravel particles are inert and if they are situated right in front of a local metering or injection location, they only deflect the additive jet, see figure 9 in this respect, and distribute the additive further.
It is apparent from figure 6 that the helical coils are at a minimum distance a from the wall of the mixing device 6. As already discussed, a blockage can occur both locally in the metering apparatuses 12, 17 of the mixing apparatus 6, which is fitted into a concrete transport pipeline, but also in the expanding diffuser and re-contracting part of the confusor apparatus. In terms of qualitative considerations, the conveying of the concrete in the cylindrical part through the mixing apparatus and around the metering elements is uniform over the cross section. For the mixer apparatus, it is particularly advantageous for the distance, firstly, from the metering apparatuses to the wall of the mixing device 6 not at any point to drop below the critical size a > 3 x dparticler preferably a = 3 to 9 x dParticler particularly preferably a = 3 to 7 x dParticlei in particular a = 5 to 7 x dPartiole = However, given an appropriate pitch of the metering apparatus, in particular of the coil, it is also possible to bring the latter to the outside. This is advantageous in particular if a relatively large area has to be supplied with additive.
Figure 10 illustrates a further possibility of configuring a metering apparatus 18. The metering apparatus here comprises pipes 19 which are angled and are each arranged twisted with respect to the other pipe in the mixing device. By means of this arrangement, a homogeneous distribution of the additive over the cross section is likewise made possible, as is apparent from the projection at the location 21.
Figure 11 shows a further possibility of configuring a metering apparatus 22. The metering apparatus here comprises pipes 23 which are likewise angled and are each arranged on a central pipe 24. The central pipe 24 is located essentially on the longitudinal axis of the mixing device 6. The pipes 23 and therefore the metering locations (not illustrated specifically) can be supplied with additive by the central pipe 24. By means of this arrangement, a homogeneous distribution of the additive over the cross section is likewise made possible.
The pipes 19 and 23 shown in figures 10 and 11 advantageously have an appropriate pitch in order to avoid the above-described problems with blockages.
The liquid additive is advantageously pumped through the metering apparatuses in such a manner that it flows at the end of the metering apparatus back through a line to the conveying pump. There is therefore a circuit. As a result, a virtually uniform pressure loss through the metering openings is obtained over the entire length of the additive line and therefore a uniform metering of the additive at every delivery location.
At an internal diameter of the metering line of 17.3 mm and a volumetric flow of 1 m3/h, the calculated pressure loss due to wall friction and outlet is approx. Ap = 0.06 bar depending on the outlet velocity.
The additive is supplied in such a manner that it has a positive pressure in comparison to the granule-suspension mixture. This permits the injection and at the same time prevents the nozzle from becoming blocked.
Of course, the invention is not restricted to the exemplary embodiment shown and described. Instead of the activator, use may be made of any desired additives or other substances which are to be mixed into a plastic-viscous mixture in relatively small amounts.
Also the plastic-viscous mixture to be used is as desired per se. Mixing devices of this type, as have been illustrated above, can therefore be used not only for mixing additives into concrete but also wherever something has to be admixed to a mixture with plastic-viscous behavior. Fields of application therefore reside in the construction industry, oil refining, pyro-metallurgical addition in the extraction of metals from ores, the alloying of metals, production of dough goods, the introduction of additives to dough, for example nuts to bread, the introduction of berries, etc. to yogurt, processing of plastics, the emulsifying of aromatic oils into various foodstuffs, the preparation of honey, the chemical industry, pharmaceutical industry, dyeing industry, etc. In particular in the production of ceramics by means of slip castings, the slips are transported to the ceramics factory and a thixotropic agent is also added to the slip prior to casting.
The course 14 of the added additive through the mixer 6 is now explained by way of example by means of a metering location 13. After being metered into the granule-suspension mixture, the additive follows the mixture as a type of additive thread. These additive threads are illustrated as spots over the cross section at the location 15. The granule-suspension mixture then flows through the confusor 11 and, at the location 16, the additives are again illustrated as spots. It can clearly be seen that the additive threads lie very much closer together because of the narrowing than at the location 15 in the cylinder 9. Thoroughly good mixing of the additive into the granule-suspension mixture or the suspension fraction is thereby achieved. The number of metering locations is advantageously n = 100 to 300, the metering locations are at a distance 1 = 10 to 70 mm, and the diameter of the metering openings is d 0.4 to 1.5 mm.
Figures 5 and 6 illustrate the mixing device 6 with a metering apparatus 12 and 17 which here comprises a first helical coil 12 and a second helical coil 17.
Said helical coils are nested together in such a manner that a homogenous distribution of the metering locations 13 takes place in the projection in the metering locations over the cross sectional surface of the mixing apparatus, see figure 7 in this respect.
Figure 8 illustrates how often gravel particles can arrive at metering locations. Gravel particles are inert and if they are situated right in front of a local metering or injection location, they only deflect the additive jet, see figure 9 in this respect, and distribute the additive further.
It is apparent from figure 6 that the helical coils are at a minimum distance a from the wall of the mixing device 6. As already discussed, a blockage can occur both locally in the metering apparatuses 12, 17 of the mixing apparatus 6, which is fitted into a concrete transport pipeline, but also in the expanding diffuser and re-contracting part of the confusor apparatus. In terms of qualitative considerations, the conveying of the concrete in the cylindrical part through the mixing apparatus and around the metering elements is uniform over the cross section. For the mixer apparatus, it is particularly advantageous for the distance, firstly, from the metering apparatuses to the wall of the mixing device 6 not at any point to drop below the critical size a > 3 x dparticler preferably a = 3 to 9 x dParticler particularly preferably a = 3 to 7 x dParticlei in particular a = 5 to 7 x dPartiole = However, given an appropriate pitch of the metering apparatus, in particular of the coil, it is also possible to bring the latter to the outside. This is advantageous in particular if a relatively large area has to be supplied with additive.
Figure 10 illustrates a further possibility of configuring a metering apparatus 18. The metering apparatus here comprises pipes 19 which are angled and are each arranged twisted with respect to the other pipe in the mixing device. By means of this arrangement, a homogeneous distribution of the additive over the cross section is likewise made possible, as is apparent from the projection at the location 21.
Figure 11 shows a further possibility of configuring a metering apparatus 22. The metering apparatus here comprises pipes 23 which are likewise angled and are each arranged on a central pipe 24. The central pipe 24 is located essentially on the longitudinal axis of the mixing device 6. The pipes 23 and therefore the metering locations (not illustrated specifically) can be supplied with additive by the central pipe 24. By means of this arrangement, a homogeneous distribution of the additive over the cross section is likewise made possible.
The pipes 19 and 23 shown in figures 10 and 11 advantageously have an appropriate pitch in order to avoid the above-described problems with blockages.
The liquid additive is advantageously pumped through the metering apparatuses in such a manner that it flows at the end of the metering apparatus back through a line to the conveying pump. There is therefore a circuit. As a result, a virtually uniform pressure loss through the metering openings is obtained over the entire length of the additive line and therefore a uniform metering of the additive at every delivery location.
At an internal diameter of the metering line of 17.3 mm and a volumetric flow of 1 m3/h, the calculated pressure loss due to wall friction and outlet is approx. Ap = 0.06 bar depending on the outlet velocity.
The additive is supplied in such a manner that it has a positive pressure in comparison to the granule-suspension mixture. This permits the injection and at the same time prevents the nozzle from becoming blocked.
Of course, the invention is not restricted to the exemplary embodiment shown and described. Instead of the activator, use may be made of any desired additives or other substances which are to be mixed into a plastic-viscous mixture in relatively small amounts.
Also the plastic-viscous mixture to be used is as desired per se. Mixing devices of this type, as have been illustrated above, can therefore be used not only for mixing additives into concrete but also wherever something has to be admixed to a mixture with plastic-viscous behavior. Fields of application therefore reside in the construction industry, oil refining, pyro-metallurgical addition in the extraction of metals from ores, the alloying of metals, production of dough goods, the introduction of additives to dough, for example nuts to bread, the introduction of berries, etc. to yogurt, processing of plastics, the emulsifying of aromatic oils into various foodstuffs, the preparation of honey, the chemical industry, pharmaceutical industry, dyeing industry, etc. In particular in the production of ceramics by means of slip castings, the slips are transported to the ceramics factory and a thixotropic agent is also added to the slip prior to casting.
List of reference numbers 1 Transport vehicle 2 Container 3 Pump 4 Line 5 Additive/activator 6 Mixing device 7 Line 8 Diffuser element 9 Cylinder element 10 Concrete, delayed 10' Concrete, activated 11 Confusor element 12 Metering apparatus 13 Metering location 14 Additive course 15 Cross-sectional projection, additive 16 Cross-sectional projection, additive 17 Metering apparatus 18 Metering apparatus 19 Pipe 20 Use location 21 Cross-sectional projection, additive 22 Metering apparatus 23 Pipe 24 Central pipe
Claims (9)
1. A mixing device (6) for metering an additive (5) into a pumpable mixture (10) with plastic-viscous behavior, in particular concrete, wherein the mixture (10) is conveyed in a line (4), characterized in that the mixing device comprises a diffuser element (8) and a confusor element (11) in the direction of flow of the mixture (10), and in that at least one metering apparatus (12, 17, 18, 22) with at least one metering location (13), by means of which additive (5) is added to the mixture (10), is arranged in the interior of the mixing device.
2. The mixing device as claimed in claim 1, characterized in that the mixing device comprises a cylinder element (9) which is arranged between the diffuser element (8) and the confusor element (11).
3. The mixing device as claimed in claim 1 or 2, characterized in that the metering locations (13) in projection are arranged homogeneously over the cross section.
4. The mixing device as claimed in claim 1, 2 or 3, characterized in that the diffuser element (8) has an expansion angle (.alpha.) of .alpha. = 1° to 60° and/or the confusor element has an angle (.beta.) of .beta. = 5° to 20°.
5. The mixing device as claimed in claim 1, 2, 3 or 4, characterized in that the metering apparatus (12, 17, 18, 22) essentially comprises a type of coil (12, 17) and/or pipes (19, 23) arranged consecutively.
6. The mixing device as claimed in one of the preceding claims, characterized in that the metering apparatus is at a distance (a) from the wall of the mixing device of a > 3 × d Particle, and/or in that the metering location is at a distance (a) from the wall of the mixing device of a > 3 × d Particle.
7. The mixing device as claimed in one of the preceding claims, characterized in that the pumpable mixture (10) with plastic-viscous behavior is a granule-suspension mixture, such as concrete.
8. A method for adding an additive (5) to a pumpable mixture (10) with plastic-viscous behavior, in particular concrete, by means of a mixing device as claimed in one of claims 1 to 7, characterized in that the additive (5) is recirculated through the metering apparatus (12, 17, 18, 22) such that a uniform outflow of additive over the entire metering element length is obtained.
9. The method as claimed in claim 8, characterized in that the additive (5) is injected at a positive pressure in comparison to the pumpable mixture (10).
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP05108813.6 | 2005-09-23 | ||
| EP05108813A EP1767322A1 (en) | 2005-09-23 | 2005-09-23 | Mixing device and method for introducing an additive into a pumpable mixture |
| PCT/EP2006/066628 WO2007033989A1 (en) | 2005-09-23 | 2006-09-22 | Mixing device and method for adding an additive to a pumpable mixture |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2626090A1 true CA2626090A1 (en) | 2007-03-29 |
Family
ID=35841735
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002626090A Abandoned CA2626090A1 (en) | 2005-09-23 | 2006-09-22 | Mixing device and method for adding an additive to a pumpable mixture |
Country Status (5)
| Country | Link |
|---|---|
| EP (2) | EP1767322A1 (en) |
| JP (1) | JP2009508725A (en) |
| CN (1) | CN101389455A (en) |
| CA (1) | CA2626090A1 (en) |
| WO (1) | WO2007033989A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2011310100B2 (en) * | 2010-10-01 | 2015-01-15 | Sika Technology Ag | Mixing apparatus for pumpable mixtures and method related thereto |
| EP2436496A1 (en) * | 2010-10-01 | 2012-04-04 | Sika Technology AG | Mixing unit for pumpable mixtures, particularly for sprayed concrete |
| EP2476530A1 (en) * | 2011-01-12 | 2012-07-18 | Sika Technology AG | Dosing unit and housing element for a mixing device |
| CN103009484A (en) * | 2012-12-20 | 2013-04-03 | 常熟市大生机械厂 | Novel concrete stirring barrel |
| CN104015264A (en) * | 2013-12-15 | 2014-09-03 | 广西鱼峰水泥股份有限公司 | Cement additive weighing device |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE460796C (en) * | 1928-06-05 | Adolf Wolfsholz | Method for spraying mortar or the like. | |
| US1848122A (en) * | 1930-02-20 | 1932-03-08 | Alois W Forster | Device for use in introducing alpha fluid into alpha conduit for flowing materials |
| CA1096630A (en) * | 1978-05-26 | 1981-03-03 | David J. Tookey | Static mixer |
| JPS6131573A (en) * | 1984-07-21 | 1986-02-14 | 鶴島建機株式会社 | Concrete spraying apparatus and accelerator mixing pipe thereof |
| DE19746958C1 (en) * | 1997-10-24 | 1999-06-17 | Friedhelm Eber | Assembly to mix building mortar, water and air and discharge through a jet |
-
2005
- 2005-09-23 EP EP05108813A patent/EP1767322A1/en not_active Withdrawn
-
2006
- 2006-09-22 WO PCT/EP2006/066628 patent/WO2007033989A1/en active Application Filing
- 2006-09-22 EP EP06793746A patent/EP1928638A1/en not_active Withdrawn
- 2006-09-22 JP JP2008531709A patent/JP2009508725A/en not_active Withdrawn
- 2006-09-22 CN CNA2006800421998A patent/CN101389455A/en active Pending
- 2006-09-22 CA CA002626090A patent/CA2626090A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| EP1767322A1 (en) | 2007-03-28 |
| EP1928638A1 (en) | 2008-06-11 |
| CN101389455A (en) | 2009-03-18 |
| WO2007033989A1 (en) | 2007-03-29 |
| JP2009508725A (en) | 2009-03-05 |
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| Date | Code | Title | Description |
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| FZDE | Discontinued |