Mixing pump system for continuous building material production and transport

Abstract

The invention relates to a mixing pump system for the continuous production and conveying of a curable building material, and to a method for its production, which makes it possible to generate a homogeneous, pumpable building material dispersion (3) in a continuous process from separately available raw building material components, namely a bulk binder (7), an aggregate (8), and mixing water (9). The mixing pump system comprises a first mixing pump (1), a second mixing pump (2), and a control unit (15) connected to both mixing pumps (1, 2), wherein a flowable binder suspension (5) is produced in the first mixing pump (1) from the bulk binder (7) and the mixing water (9). The binder suspension (5) is then fed to a mixing unit (19) of the second mixing pump (2), within which the binder suspension (5) is mixed with the aggregate (8) to form the building material dispersion (3).The mixing pump system and the process are designed for on-site use on construction sites; they are particularly suitable for the cost-effective production of cast-in-place concrete or mortar.

Description

[0001] The invention relates to a mixing pump system for the continuous production and delivery of a hardenable building material in the form of a homogeneous, pumpable building material dispersion, as well as a method for producing the hardenable building material. The mixing pump system and method are intended for on-site use on construction sites; they are particularly suitable for the cost-effective production of in-situ concrete or mortar.

[0002] The on-site production and processing of mostly viscous, pumpable building material dispersions, such as in-situ concrete, mortar, flowing screed, or sprayed plaster, is one of the most commonly used processes on construction sites. For this purpose, the building material dispersions, which typically consist of an inorganic, non-metallic binder bulk material, aggregate, and mixed water, are produced on-site using continuously operating mixing pumps. Typically, a ready-mixed mixture of the binder bulk material and aggregate is used. For the production of in-situ concrete, for example, dry concrete, a ready-mixed mixture of cement as the binder bulk material and sand as the aggregate, is used.The mixing pumps used, also referred to as plastering machines in specific applications, are portable, compact small construction machines by means of which the ready-mixed mixture is continuously processed into a building material dispersion with the addition of water and then pumped - also continuously - to the processing point via a flexible building material conveying line. Such mixing pumps are disclosed, for example, in DE 10 2007 030 458 A1 or EP 2 343 170 A1. The mixing pump can have a mixing device or mixing unit, as described in DE 10 2007 030 458 A1 or EP 1 914 056 A2, in particular for processing difficult-to-mix building material raw components. A mixing shaft integrated into the mixing unit, as disclosed in DE 10 2008 050 394 A1 or EP 2 161 074 A1, has proven particularly suitable for the continuous processing of difficult-to-mix building material raw components.

[0003] Also known from JP H02 117 109 U is a mixing pump system according to the preamble of claim 1 for the continuous production and conveyance of building materials, wherein the mixing pump system comprises a first mixing pump and a second mixing pump, and wherein the second mixing pump has a mixing unit for mixing an aggregate with a binder suspension produced in the first mixing pump.

[0004] US 530 654 A describes a mortar mixing machine comprising a lime slaker and a mixing tank located below the level of the lime slaker, the mixing tank being connected to the lime slaker via a valve line.

[0005] GB 2 610695 A discloses a unit for producing and preparing mortar for spraying it onto a construction site. The unit comprises a mixing module into which water from a water circuit and powder from a powder collector are fed. The mixing module has a mixer and a pump in which the powder and water are mixed. A control unit controls the addition of water and powder. Furthermore, the viscosity of the mortar can be controlled by a secondary water circuit.

[0006] However, the production of building materials from ready-mixed materials often has a significant cost disadvantage compared to on-site mixing of the building material from separate raw building material components. To date, discontinuous mixing devices, such as drum mixers or batch mixers, have been used to mix building materials from raw building material components on construction sites, for example, in the production of concrete. However, in batch operation, the building materials can only be delivered to the processing site with interruptions, resulting in delays in the production process; in other words, they cannot be pumped or conveyed continuously.

[0007] The object of the invention is to provide a device or plant suitable for use on construction sites for producing and conveying a hardenable building material and a method for producing the hardenable building material, which make it possible to produce a homogeneous, pumpable building material dispersion from separately present building material raw components, namely a binder bulk material, an aggregate and added water, in a continuous process.

[0008] This object is achieved by a mixing pump system for the continuous production and conveyance of a curable building material having the features of claim 1 and a method for producing the curable building material according to claim 13. Appropriate further developments of the invention are set out in claims 2 to 12 as well as 14 and 15.

[0009] According to the invention, the mixing pump system comprises a first mixing pump, a second mixing pump, and a control and regulation unit connected to both mixing pumps. The mixing pump system continuously produces and conveys a hardenable building material in the form of a homogeneous, pumpable building material dispersion consisting of an inorganic, non-metallic binder bulk material, an aggregate, and mixing water. When used as intended, the raw building material components—i.e., the binder bulk material, the aggregate, and the mixing water—are fed separately to the mixing pump system.

[0010] Both mixing pumps have the usual, familiar design of these small construction machines, i.e., a storage container into which bulk material can be poured, a mixing unit connected to a drive, and a conveying unit also connected to the drive for generating or conveying a flowable mixture, as well as connections for the mixing water and the power supply. A preferably flexible line, e.g., a hose, leading to the processing point is connected to the respective mixing pump for transporting the flowable mixture.

[0011] The first mixing pump is used to produce a pumpable, flowable binder suspension from the binder bulk material and the added water. It has a mixing unit for this purpose. A preferably flexible binder line is connected to the first mixing pump to discharge the binder suspension.

[0012] A conveying unit of the first mixing pump, which is usually designed as an eccentric screw pump, is used to convey the binder suspension.

[0013] The second mixing pump has an aggregate storage container for adding and receiving the aggregate, and a mixing unit connected to the aggregate storage container for generating the construction material dispersion. The mixing unit of the second mixing pump is referred to below as the mixing unit to distinguish it from the mixing unit of the first mixing pump. Furthermore, the second mixing pump has a discharge shaft arranged in the aggregate storage container for conveying the aggregate from the aggregate storage container into the mixing unit. The discharge shaft is designed, for example, as a conveyor screw.

[0014] According to the invention, the mixing unit or the mixing unit of the second mixing pump comprises a tubular mixing chamber designed as a housing and a mixing shaft rotatable therein for mixing the aggregate with the binder suspension to form the homogeneous building material dispersion. The binder line leading from the first mixing pump for introducing the binder suspension into the mixing unit is connected laterally to the mixing chamber of the mixing unit. The discharge shaft, which can be rotated in the aggregate storage container, is aligned coaxially to the mixing shaft, i.e. the discharge shaft and the mixing shaft rotate about one and the same axis of rotation. To transmit torque, the discharge shaft can be coupled or coupled to the mixing shaft - for example by means of a shaft coupling. The mixing shaft is inserted within the mixing chamber without fixed bearings; the mixing shaft rotates floatingly within the mixing chamber when the mixing pump is in operation.

[0015] The mixing unit of the first mixing pump preferably has a comparable or similar structure to the mixing unit or mixing unit of the second mixing pump. The mixing unit of the first mixing pump can also be designed according to EP 1 914 056 A2. In this regard, reference is made to the patent application with the publication number EP 1 914 056 A2.

[0016] A delivery unit of the second mixing pump is connected axially to the mixing unit, and to this, in turn, a preferably flexible construction material delivery line for discharging the construction material dispersion is connected. The material movement caused by the rotating mixing shaft occurs in the axial conveying direction toward the discharge end of the mixing unit. The delivery unit of the second mixing pump, connected to the discharge end of the mixing unit, serves to convey the construction material dispersion via the construction material delivery line to the processing point. The delivery unit of the second mixing pump is usually designed as an eccentric screw pump, the shaft of which is aligned coaxially with and coupled to the mixing shaft.

[0017] The control and regulation unit, connected to both mixing pumps via suitable lines, is configured to control the flow rate and to coordinate the activation and deactivation of the first mixing pump depending on the operating state of the second mixing pump. The control and regulation unit is configured, for example, to start up the first mixing pump with a defined time delay after the start-up of the second mixing pump and / or to deactivate the first mixing pump when the second mixing pump is deactivated. It can also be configured to adjust the mixing ratio of binder suspension and aggregate in the mixing unit by controlling the flow rate using predefined pump drive powers of the first and second mixing pumps.

[0018] The production of the hardenable building material in the form of the pumpable building material dispersion is carried out according to the process according to the invention from the separately present raw building material components, namely from the inorganic, non-metallic binder bulk material, from the aggregate and from the mixing water by means of the mixing pump system described above.

[0019] In the first mixing pump, the inorganic, non-metallic binder bulk material is continuously mixed with the addition of water to form a flowable binder suspension with a predetermined first viscosity. The binder suspension is then continuously fed to the mixing unit of the second mixing pump. In the mixing unit of the second mixing pump, the aggregate conveyed from the aggregate storage container into the mixing unit is then continuously mixed with the binder suspension to form the pumpable, homogeneous building material dispersion, whereby the building material dispersion has a predetermined second viscosity. This means that in the mixing unit, the binder suspension and the aggregate are mixed together by stirring using the mixing shaft and are simultaneously transported by the mixing shaft in the form of the resulting building material dispersion to the delivery unit of the second mixing pump.The hardenable building material is finally conveyed to the respective processing point via the construction material conveying line by means of the conveying unit of the second mixing pump.

[0020] Mineral, water-setting binders such as cement, lime, and / or gypsum are particularly suitable as bulk binders. Preferred aggregates are sand, gravel, and similar rock mixtures. When using cement as the bulk binder, the binder suspension can be prepared, for example, in a ratio of 100 parts cement by mass to 45 to 50 parts water by mass by continuous mixing in the first mixing pump. A binder suspension produced from cement and water is also called cement paste.

[0021] The mixing pump system according to the invention and the method implemented therewith enable the continuous supply of the curable building material produced from separate raw building material components as a pumpable building material dispersion, eliminating the need for premixed finished products. Since the costs of producing a specific quantity of building material from separate raw building material components are usually significantly lower than the costs for the same quantity of building material using premixed products, significant cost savings can be achieved by utilizing the proposed technology.

[0022] A homogeneous, pumpable construction material dispersion is achieved by blending the aggregate conveyed into the mixing unit with the binder suspension. While, for example, the singular addition of water to the conventionally used aggregate sand does not produce a pumpable mixture, the targeted addition of the binder suspension to the aggregate enables the uniform blending of the aggregate and binder suspension without any separation or demixing. The glue-like flow properties of the binder suspension ensure intensive, demixing-free blending during the stirring process as it is introduced into the aggregate conveyed by the rotational mixing shaft in the mixing unit—thus resulting in a pumpable construction material dispersion.

[0023] The shared control and regulation unit also ensures the functional interaction of both mixing pumps, in particular to convey the produced building material dispersion without interruption and with consistent consistency and quality.

[0024] According to one embodiment of the mixing pump system, the mixing shaft of the mixing unit comprises a premixing tool and a postmixing tool axially connected to the premixing tool in the conveying direction. The premixing tool and the postmixing tool can be connected to each other inseparably or separably, e.g., via a shaft coupling.

[0025] Advantageously, the premixing tool is designed as a stirrer with stirring elements that are axially aligned or run parallel to the rotation axis. This means that the premixing tool generates a stirring movement exclusively in the circumferential direction without any axial movement component.

[0026] The premixing tool is preferably designed as a frame agitator. The frame agitator comprises, for example, two radially projecting flat webs lying in one plane, mirror-inverted to the rotational axis of the mixing shaft, whose respective ends converge radially in the center and are connected. A frame agitator designed in this way can also be considered a blade agitator with a central recess in the blade area.

[0027] Furthermore, the premixing tool can also be designed as an anchor stirrer. The premixing tool designed as an anchor stirrer preferably has two- to four-fold rotational symmetry.

[0028] According to a preferred embodiment, the post-mixing tool comprises a shaft body on which one or more feed elements, one or more radial primary mixing blades, one or more radial inertia elements, and one or more secondary mixing blades are mounted axially one behind the other in the conveying direction. The post-mixing tool is designed, in particular, as the mixing shaft disclosed in EP 2 161 074 A1. In this regard, reference is made to the patent application with the publication number EP 2 161 074 A1.

[0029] The connection of the binder line to the mixing chamber, i.e. the supply of the binder suspension to the mixing unit, is preferably made at an axial position on the mixing unit in the area of ​​the pre-mixing tool. In particular, the connection to the mixing chamber is located at an axial position on the mixing unit in the rear third of the axial extension of the pre-mixing tool in the conveying direction. Furthermore, the binder line is preferably aligned transversely to the axis of rotation of the mixing shaft in the connection area, i.e. the binder suspension is introduced into the mixing unit transversely to the conveying direction. This positioning and alignment of the binder line in the connection area to the mixing chamber has proven particularly suitable for achieving intensive mixing of aggregate and binder suspension.

[0030] According to one embodiment of the mixing pump system, the second mixing pump, particularly with regard to the aggregate storage container and the discharge shaft, is designed according to the disclosure in EP 2 343 170 A1. In this regard, reference is made to the patent application with the publication number EP 2 343 170 A1.

[0031] It can further be provided that the mixing pump system – in addition to the mandatory additive water supply to the first mixing pump – has additional water introduction or addition units. For example, the second mixing pump can have a water supply device that can be controlled by the control and regulation unit for the additional, quantity-controlled feed of additive water into the aggregate storage tank. Furthermore, a control water supply can be installed on the inlet side of the mixing chamber, which can be controlled by the control and regulation unit, for the additional, quantity-controlled direct feed of additive water into the mixing unit. The viscosity of the building material dispersion can be adjusted, for example, using the additional water introduction or addition units.

[0032] The invention is explained in more detail below using an exemplary embodiment and with reference to the schematic drawings, in which identical or similar features are provided with the same reference numerals; in this case: Fig. 1: the mixing pump system in plan view and partial sectional view, and Fig. 2: details of the second mixing pump in longitudinal section.

[0033] The two mixing pumps 1, 2 of the mixing pump system according to Fig. 1 are small construction machines that have the basically familiar structure of this machine type.

[0034] The first mixing pump 1 has the upwardly open binder storage tank 16 for filling the binder bulk material 7, as well as the mixing unit 18 of the first mixing pump 1 connected to the binder storage tank 16. The mixing water 9 is fed into the binder storage tank 16 of the first mixing pump 1 via the water connection 11 and mixed with the binder bulk material 7 to form the binder suspension 5. The additional water connection 11.1 (adjusting water supply) serves to feed the mixing water 9 directly into the mixing unit 18 of the first mixing pump 1. By means of the conveying unit 32 (eccentric screw pump) of the first mixing pump 1 connected to the mixing unit 18, the binder suspension 5 is conveyed via the binder line 6 to the second mixing pump 2. The first mixing pump 1 is driven by the pump drive 13.

[0035] The second mixing pump 2 has an open-top aggregate storage tank 17 for filling the aggregate 8. Additional mixing water 9 can be fed into the second mixing pump 2 via the water connections 12, 12.1 if required; mixing water 9 is supplied to the aggregate storage tank 17 via the water connection 12; mixing water 9 is fed directly into the mixing unit 19 via the water connection 12. In the mixing unit 19 of the second mixing pump 2, the aggregate 8 and the binder suspension 5 are mixed to form the building material dispersion 3; by means of the conveying unit 33 (eccentric screw pump) of the second mixing pump 2, the building material dispersion 3 is then conveyed to the processing point via the building material conveying line 4. The second mixing pump 2 is driven by the pump drive 14.

[0036] The common control and regulation unit 15 is spatially arranged on the second mixing pump 2 and is connected via suitable lines - as in Fig. 1 shown by the dashed lines - connected to the pump drives 13, 14 and the water connections 11, 11.1, 12, 12.1 for their control and regulation.

[0037] The mixing unit 19 of the second mixing pump 2 has the circular-cylindrical mixing chamber 21 and the mixing shaft 20 rotatable therein; the mixing shaft 20 rotates around the rotation axis 22. The binder line 6 is connected laterally to the mixing chamber 21. The construction material delivery line 4, which carries the construction material dispersion 3 away, is aligned coaxially with the mixing shaft 20 in the connection area to the delivery unit 33 of the second mixing pump 2.

[0038] The representation in Fig. 2shows details of the second mixing pump 2, namely the aggregate storage container 17 with the discharge shaft 30 integrated therein and the mixing unit 19.

[0039] The structure and function of the unit consisting of aggregate storage hopper 17 and discharge shaft 30 correspond to the descriptions in EP 2 343 170 A1: The rotating discharge shaft 30 conveys the aggregate 8 within the aggregate storage hopper 17 to its outlet or transition to the mixing unit 19. The (undesignated) side shafts serve to loosen the aggregate 8 during material conveyance.

[0040] From the aggregate storage container 17, the aggregate 8 is fed into the mixing unit 19, where it is mixed with the binder suspension 5 supplied by the first mixing pump 1. The connection of the binder line 6 to the mixing chamber 21 is - in contrast to Fig. 1 - shown on the left side.

[0041] Additional additive water 9 can be supplied to the mixing unit 19 via the water connection 12.1. The water is fed into the mixing chamber 21, the design of which is described in more detail in EP 1 914 056 A2, via an annular channel and several distribution openings.

[0042] The mixing shaft 20, which can be rotated in the mixing chamber 21, is composed of the pre-mixing tool 23 and the post-mixing tool 24; both are detachably connected to one another by the intermediate shaft coupling 25.

[0043] The premixing tool 23 is designed as a frame agitator, which extends in an axial plane similar to a blade agitator and is constructed as a mirror image of the rotation axis 22. The connection of the binder line 6 to the mixing chamber 21 is located in the axial end region of the premixing tool 23; the binder line 6 and the frame agitator end approximately on a sectional plane of the mixing unit 19 lying transversely to the rotation axis 22.

[0044] The post-mixing tool 24 corresponds to the mixing shaft described in EP 2 161 074 A1: It has a shaft body on which the input elements 26, the primary mixing blades 27, the inertia elements 28 and the secondary mixing blades 29 are attached one after the other in axial order according to the conveying direction.

[0045] The mixing shaft 20, composed of pre-mixing and post-mixing tools 23, 24, is aligned coaxially with the discharge shaft 30 and is detachably connected to it via the inter-shaft coupling 31.

[0046] The construction material dispersion 3 produced in the mixing unit 19 is discharged via the construction material conveying line 4 which is axially connected to the conveying unit 33 of the second mixing pump 2. List of reference symbols

[0047] 1 First mixing pump 2 Second mixing pump 3 Construction material dispersion 4 Construction material delivery line 5 Binder suspension 6 Binder line 7 Binder bulk material 8 Aggregate 9 Addition water 11, 11.1 Water connections (first mixing pump) 12, 12.1 Water connections (second mixing pump) 13 Pump drive (first mixing pump) 14 Pump drive (second mixing pump) 15 Control and regulation unit 16 Binder storage tank 17 Aggregate storage tank 18 Mixing unit (first mixing pump) 19 Mixing unit, mixing unit (second mixing pump) 20 Mixing shaft 21 Mixing chamber 22 Rotation axis 23 Pre-mixing tool 24 Post-mixing tool 25 Intermediate shaft coupling 26 Feed element 27 Primary mixing blade 28 Inertia element 29 Secondary mixing blade 30Discharge shaft 31Intershaft coupling 32Feed unit (first mixing pump) 33Feed unit (second mixing pump)

Claims

1. Mixing pump system for the continuous production and conveyance of a hardenable building material in the form of a homogeneous, pumpable building material dispersion (3) which is formed from an inorganic, non-metallic binding agent bulk material (7), from an aggregate (8) and from mixing water (9), wherein the mixing pump system has a first mixing pump (1) for producing a pumpable, flowable binding agent suspension (5) from the binding agent bulk material (7) and the mixing water (9), and wherein a binding agent line (6) is connected to the first mixing pump (1) for outputting the binding agent suspension (5), wherein the mixing pump system further comprises a second mixing pump (2), wherein the second mixing pump (2) has: - an aggregate storage container (17) for adding and receiving the aggregate (8), - a mixing unit (19) connected to the aggregate storage container (17), comprising a tubular mixing chamber (21) and a mixing shaft (20) rotatable therein, for mixing the aggregate (8) with the binding agent suspension (5) to form the building material dispersion (3), characterized in that the mixing pump system further comprises a control and regulation unit (15) connected to the first mixing pump (1) and second mixing pump (2) for controlling the delivery rate and for the coordinated switching on and off of the first mixing pump (1) depending on the operating state of the second mixing pump (2), wherein the binding agent line (6) leading from the first mixing pump (1) for inputting the binding agent suspension (5) into the mixing unit (19) is connected laterally to the mixing chamber (21) of the mixing unit (19), and wherein the second mixing pump (2) further comprises: - an output shaft (30) arranged in the aggregate storage container (17), aligned coaxially with the mixing shaft (20) and connectable thereto for conveying the aggregate (8) from the aggregate storage container (17) into the mixing unit (19), and - a conveyor unit (33) axially connected to the mixing unit (19) for conveying and outputting the building material dispersion (3) into a building material conveyor line (4).

2. Mixing pump system according to claim 1, characterized in that the mixing shaft (20) has a premixing tool (23) and a postmixing tool (24) axially adjoining the premixing tool (23) in the conveying direction.

3. Mixing pump system according to claim 2, characterized in that the premixing tool (23) of the mixing unit (19) is a frame stirrer.

4. Mixing pump system according to claim 2, characterized in that the premixing tool (23) of the mixing unit (19) is an anchor stirrer with two- to four-fold rotational symmetry.

5. Mixing pump system according to one of claims 2 to 4, characterized in that the postmixing tool (24) has a shaft body on which one or more input elements (26), one or more radial primary mixing blades (27), one or more radial inertia elements (28) and one or more secondary mixing blades (29) are attached in axial succession in the conveying direction.

6. Mixing pump system according to one of claims 2 to 5, characterized in that the binding agent line (6) is connected to the mixing chamber (21) at an axial position in the region of the premixing tool (23).

7. Mixing pump system according to claim 6, characterized in that the binding agent line (6) is connected to the mixing chamber (21) transversely to the rotational axis (22) of the mixing shaft (20) at an axial position lying in the conveying direction in the rear third of the axial extension of the premixing tool (23).

8. Mixing pump system according to one of claims 1 to 7, characterized in that the second mixing pump (2) has a water supply device which can be controlled by means of the control and regulation unit (15) for the additional, quantity-controlled feeding of mixing water (9) into the aggregate storage container (17).

9. Mixing pump system according to one of claims 1 to 8, characterized in that on the input side of the mixing chamber (21) there is a controllable water supply which can be controlled by means of the control and regulation unit (15) for the additional, quantity-controlled direct feed of mixing water (9) into the mixing unit (19).

10. Mixing pump system according to one of claims 1 to 9, characterized in that the control and regulation unit (15) is set up to start the first mixing pump (1) with a defined time delay after starting the second mixing pump (2).

11. Mixing pump system according to one of claims 1 to 10, characterized in that the control and regulation unit (15) is set up to switch off the first mixing pump (1) when the second mixing pump (2) is switched off.

12. Mixing pump system according to one of claims 1 to 11, characterized in that the control and regulation unit (15) is set up to adjust the mixing ratio of binding agent suspension (5) and aggregate (8) in the mixing unit (19) by controlling the delivery rate by means of predetermined pump drive powers of the first (1) and the second (2) mixing pump.

13. Method for producing a hardenable building material in the form of a homogeneous, pumpable building material dispersion (3) from separately present raw building material components, namely from an inorganic, non-metallic binding agent bulk material (7), from an aggregate (8) and from mixing water (9), characterized in that the method is carried out with a mixing pump system according to one of claims 1 to 12, wherein - in the first mixing pump (1), the inorganic, non-metallic binding agent bulk material (7) is continuously mixed with the mixing water (9) to form a flowable binding agent suspension (5) with a predetermined first viscosity and the binding agent suspension (5) is then continuously fed to the mixing unit (19) of the second mixing pump (2), - in the mixing unit (19) of the second mixing pump (2), the aggregate (8) is continuously mixed with the binding agent suspension (5) to form the homogeneous, pumpable building material dispersion (3) with a predetermined second viscosity, and - the hardenable building material in the form of the homogeneous, pumpable building material dispersion (3) is continuously outputted from the mixing unit (19) of the second mixing pump (2).

14. Method for producing a hardenable building material according to claim 13, characterized in that the binding agent bulk material (7) is cement, lime and / or gypsum and the aggregate (8) is sand.

15. Method for producing a hardenable building material according to claim 14, characterized in that the binding agent bulk material (7) is cement, wherein the binding agent suspension (5) is produced by continuous mixing in a mixing ratio of 100 parts by weight of cement and 45 to 50 parts by weight of mixing water (9).

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