DEVICE FOR PRODUCING A MINERAL FOAM

Description

[0001] The invention relates to a device for producing a mineral foamed material, comprising a mortar pump and / or a mortar mixer with an automatic dispensing device.

[0002] For the thermal insulation of buildings, external thermal insulation composite systems are currently offered, comprising at least one layer of mineral wool insulation board and a layer of mineral plaster. One advantage of this is that, unlike other insulation materials, such materials are non-combustible. Such external thermal insulation composite systems can be attached to concrete or masonry. A disadvantage, however, is that such composite systems have a comparatively large overall thickness due to the multiple layers. Another problem is ensuring sufficient mechanical strength between the different layers.

[0003] WO 2011 / 106816 A1 discloses a formulation for producing a fire-retardant mineral foam, each comprising one or more sulfate-aluminate cements, sulfate components, aluminum silicates, and calcium oxide-providing components. The sulfate-aluminate cement is present in a proportion selected from a range of 55 parts by weight to 85 parts by weight, the sulfate component is present in a proportion such that the sulfate content is between 5 parts by weight and 15 parts by weight, the aluminum silicate is present in a proportion such that the Al 2 O 3 content is between 3 and 30 parts by weight, and the calcium oxide-providing component is present in a proportion such that the CaO content is between 0.5 and 2 parts by weight. Furthermore, a mineral foam and a method for producing the mineral foam are described.In this process, a foam component produced in a foam generator is added to the main component of the formulation beyond a paddle mixer. This foam component consists of either a protein foam or a surfactant foam. Thus, according to the prior invention, the mineral foam, i.e., the formulation for the mineral foam, is not directly foamed; rather, the pores of the mineral foam are formed by the addition of its own foam. Instead of a mechanical foaming process, a chemical foaming process takes place, which inevitably entails environmental pollution.

[0004] DE 1 947 365 A describes a method for producing a cellular material and solid, water-bound, cellular foamed material with an inorganic, hydraulic binder. The prior invention relates to a method for producing porous foamed materials by releasing gas in a water-setting slurry containing Portland cement, high-alumina cement, or burnt gypsum, as well as a particulate, lamellar foam stabilizer, wherein the mixture is subsequently allowed to foam and set. Within a mixing chamber, to which the dry, premixed substance is fed from a solids storage container by means of a screw conveyor, on the one hand, and a liquid, in particular water, by means of a metering pump, on the other hand, a conveyor screw is arranged, which mixes the substance on the one hand and conveys it to an outlet on the other.Although this screw conveyor has approximately radially projecting mixing rods, there is no narrowing of the flow path because these mixing rods are arranged along the entire screw conveyor and therefore do not cause any narrowing in the conveying direction.

[0005] The invention disclosed in DE 32 41 193 A1 relates to a device for continuously mixing dry material with a liquid and for conveying the mixed material, comprising a storage container for the dry material, dosing fittings for adding the liquid, and a vertically arranged mixer. The mixer comprises a vertical tube in which a mixer shaft is rotatably mounted. In addition to a helical upper part, this mixer shaft also carries centrifugal blades, mixer blades, and scrapers, which are connected to the mixer shaft via webs. Drive fingers are provided at the lower end of the shaft to drive the eccentric screw of a subsequent feed pump. None of the elements connected to the mixer shaft lead to a substantial constriction of the conveyed dry material and therefore cannot cause substantial foaming.In addition, there is no provision for air supply in the lower wet area, which would be important for the mechanical formation of pores in order to keep them open.

[0006] DE 25 22 106 A1 discloses a device for the continuous static mixing of flowable materials. This device consists of a tubular housing with at least one mixing insert arranged therein, which consists of webs arranged in two intersecting planes oriented obliquely to the housing wall, with a flow-through slot located between each two webs. The device is characterized in that the webs of the two planes are arranged on a common connecting web extending perpendicular to the longitudinal axis of the webs and transversely through the housing, with which they form a single piece, and that the flow-through slots extend all the way to the wall of the housing. There is no central core or lance to stabilize these webs, so that they can be deformed under the pressure of the conveyed mortar substance.In addition, there is no possibility of supplying air, which supports the mechanical formation of pores.

[0007] A similar arrangement can be found in EP 1 206 962 A1. This discloses a component for a static mixer, which, however, is not suitable for foaming the mixed substance. The component known therefrom is produced by cutting and forming or by punching from a flat material strip and extends in a longitudinal direction defined by the material strip within, for example, a cylindrical mixer and / or conveyor tube. Here, too, there is no central core or lance running in the longitudinal direction of the respective tube to absorb forces acting in the longitudinal direction of the mixer and / or conveyor tube, and no lateral opening within the mixer and / or conveyor tube for the active or passive supply of air.

[0008] GB 608 276 A describes a machine for mixing concrete and the like, wherein sand and aggregates are placed in chambers arranged in a row and fed by a spiral conveyor extending through two chambers. Within a mixing chamber, the driven shaft there carries approximately radially projecting paddles, which both mix and convey the still-liquid mortar substance. However, this does not result in substantial pore formation because these paddles do not constrict the conveying cross-section. Accordingly, the inventor does not claim any foaming process within the mixer.

[0009] The disadvantages of the described prior art give rise to the problem that prompted the invention: to further develop a generic device in such a way that the above-described disadvantages are overcome. In particular, a mineral foam produced therewith, which itself is not part of the invention, should simultaneously fulfill the following parameters as completely as possible: non-combustibility, high thermal insulation, and low overall thickness.

[0010] This problem is solved in a generic device by the features according to claim 1.

[0011] This is achieved using a mechanical foaming device, which exposes the mass to the strongest possible pressure gradients, particularly with the creation of localized negative pressure zones where the mass can rupture. In addition, (compressed) air is supplied or injected, particularly in or near the negative pressure zones, for example, using one or more lances extending into the mixing area. If necessary, the kneading device itself can also be equipped with internal channels that ultimately lead into the mass being kneaded, allowing air to enter the mass and fill and keep open any pores that have opened up.

[0012] This mechanical foaming principle is based on the fact that in the area of ​​the discharge device of a mixing or pumping device for the mass, the free cross-section of the flow path for the mass is tapered by one, two or more flat obstacles arranged one behind the other in the flow direction of the mortar.

[0013] Such flow obstacles must be circumvented by the mass. Because, in a continuous flow, the same mass throughput prevails in the narrowed areas as in the cross-sectionally expanded areas, the flow velocity increases at the bottlenecks; at the same time, the mass must change its flow direction, possibly even several times. Due to these relationships, shearing and / or turbulence occur within the mass, which are associated with local areas of negative pressure, so that the mass further tears open existing pores and absorbs air, which prevents the pores from subsequently collapsing. This measure thus increases the volume fraction of air pores and thus also the thermal insulation capacity.

[0014] Two or more flat obstacles are arranged on at least one core or lance in the flow path of the mass. Since the mass is intended to adhere to a vertical wall – possibly even suspended from a ceiling – it must be comparatively viscous. However, this means that such a viscous mass can only be conveyed with great energy expenditure, with flow obstacles quickly resulting in enormous flow resistance. Conversely, this flow resistance also presses against the flow obstacles and attempts to "wash them away." In order for them to withstand this strong force, they must be sufficiently anchored. This is achieved by at least one lance or core, preferably arranged in the direction of flow. This is preferably a sturdy metal rod with a diameter of at least 3 mm, better still 5 mm to 25 mm, especially 10 mm to 20 mm.

[0015] Two or more flat obstacles are designed as curved plates. In contrast to linear obstacles, which can divide the mortar strand into several parts but can easily be circumvented, flat bodies form more serious obstacles for the flow and force the mortar strand to change its internal structure, which then causes it to tear further at existing pores. The curved plates have a V-shaped cross-section, with the tip of the V pointing upstream and the two free ends of the legs pointing downstream. This allows the flow behavior to be precisely adjusted. You can imagine that the plates are initially cut out with a circular outline, for example, whose diameter is e.g.corresponds to the inner diameter of the pipe section in question; by subsequent bending along a straight line passing through the center, the plates then acquire the approximate geometry of two semicircular wings that abut each other centrally; the intermediate angle in the region of the bend line is less than 180°, preferably less than 120°, in particular less than 90°, but greater than 0°, preferably greater than 15°, in particular greater than 30°. Intermediate angles of 30° to 60°, in particular around 45°, have proven particularly effective.

[0016] Furthermore, at least one connection for the active or passive supply of air is provided in the area of ​​the pipe surrounding the flat obstacles. This connection allows the mortar to absorb additional air as the pores rupture. This air can either be passively drawn in by the rupturing mortar itself or actively forced in, for example, using compressed air. A check valve may need to be installed at an air connection to prevent air, the mortar, or components thereof from escaping.

[0017] Preferably, a core or lance according to the invention is arranged concentrically with or within a tube of the mass delivery device. With a central arrangement, the forces of the resistance bodies, in particular resistance plates, projecting on both sides are balanced, and the lance ideally experiences neither bending nor lateral forces, but exclusively axial forces in its longitudinal direction. It is particularly beneficial for this purpose if the lance or core itself follows a straight, extended path and is arranged in a straight tube section, in particular concentrically with the respective tube section.

[0018] Preferably, the core or lance has, at one or both ends, at least at its downstream end, an element extending transversely or diametrically to the surrounding pipe, e.g., a welded crossbar or plate with a plane extending in the direction of flow. This has / have the function, on the one hand, of supporting the core or lance in a coaxial orientation within the pipe, i.e., of centering it against lateral forces. On the other hand, such a crossbar or plate arranged at the downstream end can be supported against axial loads by a taper within the flow path, e.g., by a cover that can be attached, e.g., screwed on, to the downstream pipe end.

[0019] In another embodiment, the pipe containing the flow obstructions could be divided along its length into several partial shells, for example, into two half-shells. In this case, the flow obstructions could be attached directly to the inner sides of these shells, in particular to the two half-shells, so that in this case, a core or lance for arranging and holding the flow obstructions would not be necessary. However, a one-piece pipe section has proven to be more pressure-resistant than a pipe section constructed from several partial shells, so that the embodiment with a core or lance removable from a one-piece pipe is generally preferable.

[0020] A pumping device, in particular a screw casing pump or a peristaltic or piston pump, is arranged upstream of the discharge device. This generates the necessary flow pressure to transport the mass to the discharge device and further through a hose connected thereto to the wall. A screw casing pump generally consists of a screw casing as the stator and a conveyor screw driven for rotation therein as the rotor.

[0021] At least one connection for the active or passive supply of air can also be provided in the area of ​​the pumping system to provide air to the mortar mixture as needed. However, the use of such air inlets in this section should be carefully considered to prevent air from being forced out of the mixture under the influence of the pump's discharge pressure. If necessary, a check valve should be installed at an air connection there to prevent air, the mixture, or components thereof from escaping.

[0022] It is within the scope of the invention that a mixing device, in particular a mixing pot, is installed upstream of the pumping device. There, the mortar can be freshly prepared, in particular from a dry mix and water, or even from individual components such as sand, cement, and / or lime, as well as water. This allows the moisture content and viscosity to be precisely adjusted according to the respective requirements.

[0023] A stirrer located inside the mixing bowl is responsible for creating a homogeneous mass from the initially separated ingredients. However, within the scope of the present invention, it is also assigned the task of creating pores within the mortar mass, which can then be enlarged at a later time if necessary.

[0024] Further advantages arise from the fact that the agitator is concentrically aligned with the screw of the pumping device. This allows the rotary drives of these two devices to be combined, if necessary, to further reduce the design effort, since only a single drive is required.

[0025] The invention can be further developed in such a way that the stirrer and the pumping device are motor-driven, preferably by the same motor, in particular an electric motor. As already explained above, the viscous mortar mass offers considerable resistance to any external influence, so a powerful electric motor with, for example, a rated power of 5 to 20 kW is recommended for the required pumping power.

[0026] While prior art stirrers generally have the shape of a mixing helix, i.e., a ring bent in the axial direction or an axially bent spiral, a stirrer according to the invention has several stirring vanes or the like branching off radially from a central axis. These do not guide the mortar continuously along an entire helix, but rather only induce partial movement, leaving it to the mortar itself to ensure the necessary pressure equalization, knowing full well that this creates local areas of negative pressure where increased pores can form.

[0027] The invention proposes that several propeller-like stirring vanes be arranged within a common propeller plane, traversed approximately perpendicularly by the central axis of the stirrer. In this way, the mortar mass is moved in a common direction of rotation in the respective plane, while this is not the case in neighboring planes. Thus, a velocity gradient forms in the mortar mass in the axial direction, resulting in shearing of the mortar mass—relative movements within the mortar mass that promote pore formation.

[0028] By - as the invention further provides - one or more stirring vanes are set relative to the propeller plane so that their main planes enclose an angle α ≠ 0 with the propeller plane, the rotary movement of the stirrer imparts to the mortar mass, in addition to a rotating flow, an axial movement component which forces far more complex compensating movements in the mortar mass, in particular if the axial movement component is greater or lesser than the material transport caused by the feed pump due to the choice of the pitch of the vanes, or if an axial flow counter to the pump delivery direction is possibly even caused due to a pitch of the vanes in the opposite direction.

[0029] Particularly advantageous properties can be achieved if at least two agitator vanes are positioned in opposite directions within the propeller plane. This results in different axial movements being imposed on the mortar mass in the propeller plane during one rotation of such agitator vane propeller. These movements can then combine with each other and form turbulence, which also severely influences the internal structure of the mortar mass and promotes the formation of pores.

[0030] Furthermore, at least one connection for the active or passive supply of air can be provided within the mixing device. This allows the mortar to be supplied with air at this point as well, if necessary, to fill any pores that may have formed.

[0031] A thermal insulation material that can be produced using the device according to the invention, which itself is not part of the invention, combines the properties of thermal insulation and a (base) plaster in a single layer and is therefore multifunctional, i.e., several functions such as thermal insulation and mechanical cohesion in a single layer, so that one layer can be saved compared to the prior art and the overall thickness of this material is increased compared to known composite systems. This does not have to compromise either the thermal insulation capacity or the non-flammability. A further advantage is that, although this material can be prefabricated, it can also be processed on site while still in a liquid, pasty, or plastic state and can therefore be optimally adapted to local conditions; in particular, this allows the creation of a maximally strong bond with a substrate.With the exception of possible functional additives, the composition according to the invention preferably does not contain any further additives besides the heat-insulating additives.

[0032] It has proven advantageous that the volume ratio between additives, in particular heat-insulating additives, e.g. lightweight aggregates, and binder is 1:1 or more, for example 2:1 or more, preferably 3:1 or more, in particular 4:1 or more, and / or in a range between 1:1 and 4:1.

[0033] Since the thermal insulation properties of the binder are generally poorer than those of the thermal insulation additives, the binder should only be used to the extent that is essential for the basic mechanical stability of the layer in question. For this purpose, a binder proportion of around 25 vol.% in the dry mix should be sufficient, for example 20 vol.% or less, preferably 15 vol.% or less, in particular 10 vol.% or less. The stated volume fractions are always given as bulk volume, in particular with a bulk density that complies with the standard. In this context, it should be mentioned that with granules, i.e. mixtures of a granular solid, the so-called bulk material, and a continuous fluid which fills the cavities between the particles, e.g.Air or water, different quantities are used to determine density, in particular the true density, the raw density, the tapped density and the bulk density. While the true density describes the density of the pure solid component, as it results without pores and gaps, the raw density is based on a raw volume, which includes any pores in the granulate particles. The bulk density is based on the bulk volume, which is established during a standardized pouring process from a standardized height and, in addition to the pores in the particles, also includes the spaces filled with the continuous fluid. The tapped density is calculated using the tapped volume that the granulate takes up after a standardized pouring process and one or more standardized tamping processes. The tapped density and the bulk density can be determined using the so-calledHausner factors are linked to one another, with a Hausner factor of 1 meaning that the granulate in question is hardly or not at all compacted when tamped. Like the pure and bulk density, the bulk and tamped densities are purely material quantities that depend on particle size and shape and the resulting pouring and compaction behavior. In this respect, the standardized bulk density of a granulate can be determined, for example, according to DIN EN ISO 60 [2] and DIN EN ISO 61 [3] for measuring bulk density and flowability; special measuring devices are commercially available for this purpose. Tables also exist with the bulk densities of a wide variety of materials. For example, Römpp's ChemieLexikon, 7th edition, under the keyword "bulk density," gives the bulk density for cement in powder form as 1,200 kg / m 3<, for building gypsum as 1,250 kg / m 3<, and for sand as 1,800 kg / m 3<.

[0034] Depending on the lightweight aggregate used, the weight ratio between binder and thermally insulating lightweight aggregate can vary widely. It is therefore not readily possible to specify a mass or weight ratio for the dry mix. Nevertheless, the weight ratio between thermally insulating additives and binder is generally equal to or greater than 1:1, for example, 1.2:1 or more, preferably 1.4:1 or more; otherwise, the ratio is usually 3:1 or less, for example, 2.5:1 or less, preferably 2:1 or less, and in particular 1.8:1 or less.

[0035] In a water-mixed but not yet foamed state, the volumetric ratio of the heat-insulating additives and the binder / water fraction in the wet mixture is generally equal to or greater than 3:1, for example 4:1 or more, preferably 6:1 or more, in particular 10:1 or more; on the other hand, this volumetric ratio is usually 25:1 or less, preferably 20:1 or less, in particular 18:1 or less.

[0036] Preferably, the mass that can be produced with the device according to the invention has the following composition in the foamed and set state: ≤ 7.5 vol.% binder, ≥ 22.5 vol.% thermal insulation additives; and ≥ 70 vol.% air voids.

[0037] In the foamed and cured state, any previously added water is already bound as water of crystallization. It can be seen that, on the one hand, the volume ratio between additives and binder of at least 3:1 is maintained, and, on the other hand, that the pores occupy at least about two-thirds of the total volume.

[0038] With a more specific composition, namely the following: With ≤ 5 vol.% binder, ≥ 20 vol.% thermal insulation additives, and ≥ 75 vol.% air voids, the air voids constitute at least three-quarters of the total volume in the foamed and cured state. Furthermore, the volume ratio of thermal insulation additives to binder is even 4:1 or greater. As a result, the thermal insulation capacity of such a composition is increased.

[0039] The following composition offers even better thermal insulation properties for the foamed and cured state: ≤ 4 vol.% binder, ≥ 16 vol.% thermal insulation additives; and ≥ 80 vol.% air voids.

[0040] The air pores even comprise at least four-fifths of the total volume, so that excellent thermal insulation properties can be achieved.

[0041] The binder content in the unconsolidated dry mix can be between 1 and 50 vol.%, for example between 1 and 40 vol.%, preferably between 1 and 30 vol.%. It can be seen that the binder content can be reduced to a very small residual value of only about 1 vol.%.

[0042] The proportion of thermal insulation additives in the unconsolidated dry mix should be between 50 and 99 vol.%, for example, 60 vol.% or higher, preferably 70 vol.% or higher. The combination of such a high thermal insulation content with a high air void content ultimately leads to an optimal thermal insulation value, so that the layer thickness can be minimized despite the mineral insulation. For example, the thickness of the produced thermal insulation layer is 20 cm or less, preferably 15 cm or less, especially 12 cm or less. The target layer thickness is between 8 and 10 cm, i.e., in the range of typical plaster and insulation thicknesses.

[0043] An inorganic binder, particularly lime, cement, or gypsum, in pure form or as a blend, is preferred. Other inorganic binders, such as silica or water glass, may also be considered. The question of whether the binder hardens hydraulically or not is generally of secondary importance.

[0044] Further advantages arise from the fact that at least one heat-insulating additive has pores or other cavities, for example, in a volume fraction of 10 vol.% or more, preferably in a volume fraction of 30 vol.% or more, in particular in a volume fraction of 50 vol.% or more, in each case based on the volume of the additive. Such heat-insulating additives inherently have very good thermal insulation properties and contribute this directly to the thermal insulation coefficient of the produced mass or layer.

[0045] It has proven useful to use at least one heat-insulating additive containing silicon dioxide SiO 2, for example in a weight fraction of at least 25 wt.%, preferably in a weight fraction of at least 35 wt.%, in particular in a weight fraction of at least 45 wt.%, in each case based on the weight of the additive. It has been found that the structure of silicon dioxide is sufficiently strong to provide sufficient mechanical stability despite a high pore content.

[0046] The thermal insulation additive(s) can consist of one or more of the following substances: vermiculite, perlite, aerogels, expanded glass, synthetic glass foams, hollow glass spheres, glass flakes, or porous mineral sands, natural or synthetically produced, such as pumice or tuff. These materials have good thermal insulation properties, which are of great value, mostly due to their high pore content. Many of these materials are silicate minerals, which are preferred as thermal insulation additives. Vermiculite, for example, is a phyllosilicate; perlite is volcanic glass, also known as obsidian, and contains quartz, cristobalite, and feldspar. Aerogel is often made from silicate glass, e.g., using silicic acid, and can have up to 99.98 vol.% pores. Expanded glass and foam glass are usually made from recycled glass, while glass flakes are generated in the glass industry or can be deliberately produced.Pumice is a porous, glassy volcanic rock whose mineral content consists of hardened lava and therefore has around 45 to 70 wt.% SiO2; tuff rock is also of volcanic origin and essentially consists of solidified pyroclastics. The powdered mixture should be wetted before foaming, especially with water. This provides the binder with the necessary H2O, which the binder needs for its setting process and is incorporated into its structure in the form of crystal water. Due to the desired processability on site and without the need for a separate energy supply, burnout materials, for example, are not suitable as pore formers. The heat-insulating additives are usually in the form of granules of hard, porous particles in their unset state, e.g. in the form of expanded glass or similar., wherein the shell or matrix of the particles is wettable by the binder to form a three-dimensional matrix; the binder is usually present in powder form and already mixed into the dry mix. In the interest of an easy-to-use material, chemical foaming agents, which would only be added shortly before setting, can be dispensed with. Instead, the invention provides for the wet mineral mixture, in its mixed state, to be provided with pores using a mechanical foaming device. This can preferably be a type of kneading device that creates a pressure gradient within the mixed substance, in particular with local negative pressure areas. There, the moist mass can rupture and pores form. If air is actively introduced or at least passively offered in these areas, these pores do not subsequently close again, but remain until processing.An optimal result is therefore obtained when the wet mineral mixture is foamed with active or passive air addition in combination with a static mixer, e.g. using one or more lances that project into the mass and deliver (compressed) air.

[0047] In order to prevent the resulting air pores from being destroyed again during subsequent processing, it may be advisable not to process the wet mineral mixture by spraying, but rather by bubbling, i.e. only under moderate pressure, which is preferably so low that the moist mass just bubbles out loosely from a hose or similar, but does not spray out under pressure.

[0048] To improve the strength properties, the powdered or wet mineral mixture can be mixed with fibers, particularly glass fibers, which serve as internal reinforcement when cured. Alkali-resistant glass is preferred for this purpose.

[0049] To improve mechanical strength, the cured material can contain a fabric or be applied to a fabric, in particular a 3D fabric and / or a honeycomb structure. Such a fabric or structure can also serve as reinforcement. Honeycomb structures that are open on one or both sides have proven to be suitable. These structures preferably consist of a plurality of adjacent circles or polygons, e.g., hexagons, squares, or triangles, and thus form a flat network into whose recesses the mass produced with the device according to the invention can penetrate and anchor itself.

[0050] In a first, preferred application, the cured material is used as a coating for a load-bearing component, particularly applied to it, especially as plaster on a wall or ceiling. This technique can be used to insulate and plaster exterior walls simultaneously. The compound is preferably used on exterior walls, although it can also be used on interior walls.

[0051] It is possible to cover the cured material with a finishing coat. This can serve, for example, to close the pores to the outside if water-repellent properties are desired, or it can cover fibers contained in the mass produced with the device according to the invention, both to protect them and for aesthetic reasons.

[0052] On the other hand, it is also possible for the foamed material to serve as a filling in a hollow structure, for example, in one or more hollow bricks. In this case, the overall properties are particularly important, i.e., the combination of thermal and sound insulation as well as strength.

[0053] The cured material can also be self-supporting, for example, in the form of a panel and / or a room divider. In this case, the binder content will generally be higher than in other applications involving load-bearing structures. Reinforcement should also be used in these cases; this can be in the form of embedded fibers, but also in the form of fabrics and / or honeycomb structures.

[0054] The cured substance can have a thermal conductivity of 0.02 to 0.06 W / (m*K). The thermal conductivity is defined in DIN 4108. It is a measure of the thermal conductivity λ of a building material; its unit is watts per meter (thickness) and Kelvin temperature difference. The above range limits therefore indicate that in a steady state, a heat flux of 0.02 to 0.06 W flows through an area of ​​1 m2<—i.e., a heat quantity of only 0.02 to 0.06 joules per second—if there is a perpendicular temperature gradient of 1 K / m.

[0055] A method for producing a predominantly inorganic, in particular mineral, material for the purpose of thermal insulation in construction, in particular for coating load-bearing structures and / or for filling cavities or as a self-supporting component, comprising at least one binder and at least one thermally insulating additive, is characterized in that the material is foamed before setting, in particular mechanically foamed, such that in the set state it has a solid consistency with a three-dimensional matrix, the structure of a foam and a pore volume of 60 vol.% or more, preferably 70 vol.% or more, in particular 80 vol.% or more. Mechanical foaming offers the advantage that no chemical reaction is required for foaming, i.e. a single, chemically stable mixture can be used which sets solely through the addition of water.

[0056] Further features, details, advantages, and effects based on the invention will become apparent from the following description of a preferred embodiment of the invention and from the drawings. Herein: Fig. 1 a schematic representation of a mortar mixing and pumping device according to the invention; Fig. 2a stirrer for the mixing device upstream of the pumping device according to Fig. 1 ; Fig. 3 a core or lance with flow obstacles for the mortar delivery device downstream of the pumping device made of Fig. 1 ; and Fig. 4 a device according to the Fig. 1 to 3 plastered wall section, partially demolished.

[0057] To plaster a wall 31, for example a wall made of fired bricks 32 with preferably vertical, groove-shaped depressions 33, a reinforcing mesh 34, for example made of nylon or the like, is first attached there.

[0058] The mass for the plaster 35 is then mixed: For this purpose, for example, a granular or powdered thermal insulation additive is dry-mixed with a binder in a volume ratio of approximately 4:1, if necessary also 3:1 or 2:1 or 1.5:1, down to 1.2:1; but possibly also up to 5:1. As a thermal insulation additive, for example, perlite or aerogel based on silicate glass is used, and as a binder, for example, cement or lime or gypsum or mixtures thereof.

[0059] After mixing these components, the dry mix is ​​diluted with water, whereby the required amount of water depends primarily on the desired consistency. During setting, the water is partially converted into crystal water; any excess water can evaporate.

[0060] During or after mixing, the wet mass is foamed in a foaming device. This device can be installed downstream of a mixing device. In such a mixing device, the mass is stirred by a large number of moving elements until the dry mix and the mixing water are distributed as evenly as possible.

[0061] The mortar mixing and pumping device 1 according to the invention can be fed with a dry mix or with the individual ingredients for the mortar via a feed device 2. From there, the still-dry mortar mixture then flows, for example, via a screw conveyor 3, into the actual mixing chamber or mixing pot 4, where the required amount of water is added and then mixed with the dry mix.

[0062] The mixing process is carried out by a stirrer 5, which rotates about an axis 6, which in the example shown is approximately vertical, and is driven by an electric motor 7 on top of the mixing chamber or mixing pot 4. This is preferably a powerful electric motor 7 with a nominal power of 5 kW or more; moreover, a reduction gear can be provided between the electric motor 7 and the stirrer so that the stirrer rotates slowly but powerfully and is able to impose its movement on the viscous mortar mass.

[0063] The stirrer 5 is in Fig. 2reproduced in an enlarged perspective view. In addition to two frame-shaped, in particular U-shaped, stirring extensions 8, 9, which are diametrically opposed to one another with respect to the stirrer axis 6 and whose webs 10 can at least partially be located at different axial heights, one can see two further stirring extensions 11, each offset by approximately 90°, each comprising, for example, a radial stirring blade 12 and a blade 13 projecting approximately perpendicularly from the respective blade plane and extending predominantly in the axial direction.

[0064] It can also be seen that both the radial webs 10 of the U-shaped stirring extensions 8, 9 and the radial stirring blades 12 of the additional stirring extensions 11 are set in the direction of rotation relative to the main plane traversed vertically by the stirrer axis 6; however, at least one stirring blade 12 of an additional stirring extension 11 - preferably the stirring blades 12 of both additional stirring extensions 11 - is set in the opposite direction to the radial webs 10 of the U-shaped stirring extensions 8, 9. As a result, during continuous stirring, alternating upward and downward axial movements are caused within the mortar mass, which can create turbulence that is particularly conducive to pore formation.

[0065] How Fig. 1further shows, above and / or below these stirring extensions 8, 9, 11 there are further stirring blades 14, 15, which lie approximately within a plane through which the stirrer axis 6 passes vertically and extend approximately radially away from the stirrer axis 6. The stirring blades 14, 15 are also set in the direction of rotation of the stirrer 5 relative to the main plane through which the stirrer axis 6 passes vertically; however, here too at least one stirring blade 14 or possibly even two stirring blades 14 are set in the opposite direction to the other stirring blades 15 of this propeller-like stirring blade arrangement 14, 15. As a result, during continuous stirring, alternating upward and downward axial movements are caused within the mortar mass, which can lead to turbulence, which is particularly conducive to pore formation.Furthermore, these impellers 14, 15 can be present in the same number n as the impeller extensions 8, 9, 11 and can be offset by 180° / n from each of them – i.e., always approximately midway between two adjacent impeller extensions 8, 9, 11 to ensure turbulence there as well. All impellers 14, 15 and extensions 8, 9, 11 consist, for example, of 5 mm thick flat iron pieces, which are welded, for example, to the impeller shaft 6.

[0066] A screw casing pump 16 is then connected to the bottom of the mixing chamber or mixing pot 4, the screw axis of which is preferably in common alignment with the agitator axis 6, and which can be plugged together with the agitator axis 6 in a form-fitting and thus rotationally locking manner during assembly, so that the conveyor screw of the screw casing pump 16 can also be driven by the electric motor 7.

[0067] Of course, all components of the mortar mixing and pumping device 1 according to the invention are easily dismantled so that they can be easily cleaned after use and the mortar mass does not solidify inside the machine.

[0068] This also applies to the mortar discharge device 17 located downstream of the screw casing pump 16: This is connected to the outlet of the mortar pump 16—possibly with the interposition of an elbow 18—and essentially consists of a straight pipe 19, onto the end of which a cover 20 is screwed, tapering the flow cross-section. This cover, in turn, has connecting elements 21 for a hose (not shown), e.g., locking elements similar to elbow joints or the like.

[0069] A core or lance 22 is supported on the upstream edge of the cover 20, which tapers the flow cross-section, with a plate 23 arranged at its downstream end. The core or lance 22 consists of a solid metal rod with a diameter of at least 5 mm, preferably approximately 10 mm to 20 mm, and extends concentrically and coaxially within the tube 19, ideally over its entire, straight length. The core or lance 22 is held in this central position by another plate 24 at its upstream end, which can have approximately the same dimensions as the downstream metal plate 23, namely a rectangular shape with an extension transverse to the core or lance 22 that approximately corresponds to the inner diameter of the tube 19. The two holding plates 23, 24 can lie in a common plane together with the longitudinal axis of the core or lance 22 or can be offset from one another, e.g.by an angle of 90° relative to the longitudinal axis of the core or lance 22.

[0070] Between its two ends, the core or lance 22 carries several flat flow obstacles 25. These flow obstacles 25 are each bent from an originally round sheet metal blank, the diameter of this sheet metal blank approximately corresponding to the inner diameter of the tube 19. These sheet metal blanks each have a through-hole in the middle for the core or lance 22 to pass through. Furthermore, they are bent or folded in such a way that two approximately congruent halves 26 are formed, with the bending line 27 running through each of the through-holes and thereby dividing the sheet metal blank into two equal halves 26. However, these two halves 26 are not parallel to one another, but diverge from one another at an angle that is preferably approximately between 30° and 60°.A cross-section through such a flow obstacle 25 can therefore be described as V-shaped, with the two legs of the V each corresponding to a half 26 of the obstacle 25, and the tip of the V corresponding to the bending line 27.

[0071] These flat flow obstacles 25 are placed one after the other on the core or lance 22 in such a way that the bending line 27 is located upstream of the halves 26, thus the tip of the V points upstream.

[0072] In addition, the flow obstacles 25 are aligned in such a way that the bending lines 27 of successive flow obstacles 25 do not run parallel to each other, but are rotated relative to each other around the longitudinal axis of the core or lance 22, for example by an angle of 90°, as can be seen from Fig. 3 visible.

[0073] Finally, successive flow barriers 25 are spaced apart by a distance that is preferably in the range of the radius and the diameter of the pipe 19. In these positions, the flow barriers 25 are fixed, preferably welded, to the core or lance 22.

[0074] When the feed pump 16 is activated, the mortar flows through the pipe 19. It is forced to flow around each of the flow obstacles 25, changing the gradient of flow direction and velocity within the flow. This causes a fluctuating pressure distribution within the mortar mass with local areas of negative pressure, which causes existing pores to rupture and thus significantly increases the pore content.

[0075] To ensure that the mortar can be supplied with air when needed to promptly fill any pores that may form and thus prevent them from collapsing, air supply openings 28, 29 are provided, particularly in the pipe 19, but possibly also on the screw casing pump 16. These can either communicate with atmospheric air pressure or be supplied with compressed air. Furthermore, a check valve can be provided at each of these air supply openings 28, 29, which allows air to enter the interior while preventing the escape of air or mortar components.

[0076] The pumping device pumps the plastering compound 35 to an outlet 30 without exerting great pressure. If, for example, a hose is connected to a downstream connection 30 of the pipe 19, the mortar 35, which is enriched with air pores, bubbles out loosely and can then, for example, be pumped to a house wall 31 and used there for plastering. On the wall 31, it can flow around a reinforcing mesh 34 there and fill the groove-shaped depressions 33 without the internal pores being able to close again. The plastering compound 35 is smoothed mechanically, e.g., with a plastering trowel, and finally hardens on the wall 31.

[0077] The improved thermal insulation properties of such a plaster often eliminate the need for additional thermal insulation with, for example, organic substances. The advantage is that inorganic substances, especially mineral compounds based on lime and / or gypsum and / or cement, even as two- or three-component mixtures, are generally non-combustible. These compounds can also be used for screed, for dry- or wet-mortar walls, or for processing into thermal insulation boards, etc.

[0078] Further advantages of such mineral masses are that they are permeable to diffusion and allow moisture to pass through, and that they can be applied and processed very easily, if necessary in several layers up to a total layer thickness of the order of 5 cm, for example.

[0079] Depending on the application, the hardened plaster 35 can be reworked, e.g. provided with a water-repellent finishing plaster and / or painted.

[0080] For larger surfaces, to facilitate adhesion while wet, the mass 35 can be filled behind a formwork mounted in front of the wall 31, for example, at a distance of up to 20 centimeters, for example at a distance of 15 cm or less, and / or at a distance of 2 cm or more, preferably 4 cm or more, and / or at a distance of 6 to 12 cm, in particular at a distance of 8 to 10 cm. If the formwork is removed after curing, the plaster layer 35 remains with a maximally smooth and even surface, or it has a defined structure corresponding to a structural matrix inserted into the formwork.

[0081] On the other hand, a mass 35 produced with the device according to the invention can also be filled into cavities of the bricks 32 or other stones, e.g., sand-lime bricks or cement blocks, etc., in order to improve thermal and / or sound insulation properties.

[0082] Furthermore, a mass 35 can also be processed into self-supporting components, in particular panels, by not curing on a supporting structure, e.g., a wall 31, and thereby bonding to it, but rather by curing without such a supporting structure, e.g., on a flat, smooth base plate, e.g., made of metal, from which it is subsequently removed after curing. To further stiffen such a panel, it can be covered, for example, with strips of a flat medium, e.g., paper. List of reference symbols 1 Mortar mixer and pump 26 half 2 Feeding device 27 Bending line 3 screw conveyor 28 Air supply opening 4 mixing bowl 29 Air supply opening 5 stirrer 30 Hose connection 6 axis 31 Wall 7 electric motor 32 brick 8 stirring process 33 Groove 9 stirring process 34 Reinforcing mesh 10 web 35 plaster 11 stirring process 12 agitator blades 13 wing 14 agitator blades 15 agitator blades 16 feed pump 17 Mortar dispensing device 18 Knee piece 19 Pipe 20 Lid 21 Connection element 22 Soul or lance 23 plate 24 plate 25 Flow obstacle

Claims

1. Apparatus for preparation of a mineral foamed material (35), comprising a mortar pump and / or a mortar mixer (1) with an automatic dispensing facility (17) characterized in that the free cross-section of the flow path of the mortar is tapered in the area of the dispensing facility (17) by two or more flat obstacles (25) which are arranged on a central axial core or lance (22) one after another along the flow direction of the mortar, and which have the form of curved plates with a V-shaped cross-section. wherein the tip of the V points upstream, whereas the two free ends of the legs point downstream, and wherein at least one connection (28) for an active or passive air supply is provided in the area of a pipe (19) surrounding the flat obstacles (25).

2. Apparatus (1) according to claim 1, characterized in that the core or lance (22) extends concentrically to a pipe (19) of the dispensing facility (17).

3. Apparatus (1) according to one of the claims 1 to 2, characterized in that the core or lance (22) comprises, at its downstream end, a plate (23) which extends transversely or, respectively, diametrically to the surrounding pipe (19) and which is supported against the flow direction by a lid (20), which is attachable, for example screwable, on the downstream pipe end.

4. Apparatus (1) according to one of the claims 1 to 3, characterized in that a pumping facility (16) is prefixed upstream of the dispensing facility (17), for example a progressive cavity pump or a hose pump or a piston pump, wherein at least one connection (29) for an active or passive air supply is provided, preferably in the area of the pumping facility (16), and / or wherein a mixing facility, especially a mixing pot, is prefixed upstream of the pumping facility (16).