EP0218864A2 - Device and method for continuously making a hydraulically setting mass - Google Patents

Abstract

The device has a tubular housing (10) which has a loading point (12) and a discharge opening (20). A driven rotating shaft (32) is mounted in the housing, which causes a flow through the housing. The shaft (32) carries tools for metering (34), mixing (40, 46), fine comminution (52, 54) and optionally for installing fibers (60, 62) in the conveying direction. Water can be added via a connection (14). The device continuously delivers fiber concrete of constant consistency with adjustable fiber content and adjustable fiber length.

Description

The invention relates to an apparatus and a method for the continuous provision of hydraulically setting compound, in particular wet mortar or dry mortar, preferably with a proportion of fibers. A preferred field of application is the production of fiber concrete, in particular glass fiber concrete, but also concrete containing steel fibers, plastic fibers, etc.

According to the state of the art, continuous production of fiber concrete takes place solely in a spraying process. However, this is accompanied by considerable material losses, particularly in the material-consuming and correspondingly cost-intensive fibers. Known mixing processes for the production of fiber concrete, on the other hand, run discontinuously. The hydraulically setting matrix is first prepared, whereby it must be adjusted to an extremely soft consistency using additives. Both the preparation of the matrix and the installation of the fibers require the use of trained specialists. It is also hardly possible to have a consistent consistency of the fiber concrete in successive batches and to achieve an equal fiber content.

The object of the invention is to provide a structurally inexpensive, compact and user-friendly device and a method with which a hydraulically setting compound, in particular wet mortar or dry mortar, can be continuously provided in a consistency which is excellently suitable for the incorporation of fibers, and in particular a continuous one Allow the production of fiber concrete with good material utilization and consistently reproducible, constant composition and consistency.

This object is achieved by a device according to claim 1 and a method according to claim 19.

The invention enables the production of fiber concrete in a continuous mixing process. In this way, fiber concrete of constant, but widely variable composition is provided in a constant flow of material without the material losses associated with a spraying process occurring. The type, length and amount of fiber can be varied within wide limits. The fibers are carefully incorporated into the mortar by the mixing process, and due to the provision in a continuous stream of material, which preferably only passes through the device according to the invention, there is no risk of damaging or destroying the fibers by mixing for too long.

The device has a housing which has a loading point and a discharge opening. A driven rotating shaft is accommodated in the housing, which causes a conveying flow through the housing. The shaft is arranged one behind the other in the conveying direction arranged tools for dosing, mixing, crushing and, if necessary, for installing fibers.

The construction of the device is simple and compact, and the settings to be made are simple, so that they can also be made by unskilled personnel. For example, the output of the device can be regulated by changing the speed of the shaft. Of course, the device can also be operated at a constant speed. A change in the output can then possibly be brought about by exchanging the metering shaft.

In a preferred design, the housing is substantially cylindrical and possibly conical in places, and the shaft is accommodated in the center and axially in the housing and is preferably mounted twice. This gives a particularly robust, compact structure. The housing can be divided into sections, which can preferably be connected with a quick-release fastener. The device can thus be disassembled into handy and easily transportable segments and quickly assembled and disassembled, which in particular makes cleaning easier.

A storage container can be provided at the loading point of the device, for example in the form of a top box or silo connection. This means that both sack loading and silo loading of the device can take place, with minimal conversion work. A dosing screw, which sits on a section of the shaft inside the storage container, is preferably used to discharge the material from the storage container. In this way, a precisely predeterminable dry substance dosage is obtained in a structurally uncomplicated manner.

The housing can have a preferably central cross-sectional constriction in the outlet area of the storage container, through which the shaft with the metering screw protrudes. This narrowing of the cross section results in a material jam on the outlet side of the storage container, which facilitates keeping the metering rate constant. Furthermore, the narrowing of the cross section flawlessly separates a drying zone of the device, to which the storage container belongs, from a wet zone which may follow downstream. When the device is switched off and the delivery flow is interrupted, water does not penetrate into the reservoir. This is extremely important because in practice there is always the need to interrupt the production of the fiber concrete at short notice. Shutdowns of a certain duration, e.g. B. 10 to 15 minutes are possible with the device according to the invention without special measures; it then starts up again promptly and without any problems.

Downstream of the metering zone of the device according to the invention is a mixing zone in which the shaft carries mixing blades projecting radially therefrom, at least some of which can be set at an angle to the conveying direction. Together with the mixing, these mixing blades cause the mass to be transported forward. They can be equipped with wipers bearing against the inner tube wall and / or the end face of the cross-sectional constriction, which in a preferred embodiment extend in the axial direction and are attached to the tips of a pair of mixing blades. These scrapers intensify the mixing and ensure that the mixing zone extends right up to the inner wall of the pipe. The latter is constantly scraped free, which is accompanied by a bearing of the shaft. Working wipers on the cross Narrowed section of the housing keeps this area free of wet mass, so that the period is extended over which the device can be left switched off without problems.

In the area of the mixing zone, the housing can have a peripheral water connection, preferably with at least a slightly current-repellent spray direction. When water is added, mortar can be mixed with the device according to the invention, as is necessary for the production of fiber concrete. By feeding in water with the spray direction downstream, the water is kept away from the metering zone and storage container, so that the possible switch-off time of the device is in turn extended. However, it should be emphasized that the device according to the invention does not necessarily have to work with the addition of water; it can also be used to prepare a hydraulically setting dry mass, preferably with a fiber component.

Downstream of the mixing zone there is a fine grinding zone, which, however, can also be omitted if necessary. As a fine comminution tool, the shaft carries at least one comb which engages with at least one further comb which is arranged in a housing-fixed manner according to the key-lock principle. The combs can extend in the axial direction and have essentially radially directed pins. It is recommended to use a plurality of combs which are preferably offset in the circumferential direction at the same angular distance. With the latter one achieves a homogenization and pasty adjustment of the mass, which as a result is very fluid and practically free of lumps and is excellently suited for the installation of fibers. It is not absolutely necessary to add relatively complex additives required, but it can of course be done if necessary, for example by feeding in together with the mixing water.

A fiber input point with a chute opening into the housing can be located downstream of the fine comminution zone. In the area of the chute, the shaft carries a spiral axial screw and optionally further fiber installation tools, for example in the form of pins which protrude radially from the shaft, preferably in the circumferential direction counter to the direction of rotation of the shaft. The latter result in an even, gentle installation of the fibers. Sensitive fibers can also be used in this way, which would be destroyed by the previous intensive work-up of the hydraulically setting mass. Working in a continuous flow of material limits the dwell time of the fibers in the area of the conveyor line and fiber installation pins in a well-defined manner, so that damage or destruction of fibers by the mixing in is effectively prevented.

The fibers can come from a cutting unit, which is arranged upstream of the chute and should be adjustable with regard to the quantity and length of fibers fed. The composition of the mass obtained can be easily regulated on the basis of the operating parameters of such a cutting unit.

The housing of the device can taper conically downstream from the chute towards the discharge opening and can contain a correspondingly conically tapering screw section on the shaft. In this conical end part of the housing, the fiber concrete is gently mixed.

The device according to the invention has a control unit that starts the shaft with a lead in terms of fiber addition when it is started and stops with a lag in terms of fiber addition when it is switched off. Two selectable pre-air periods of the shaft can be provided, one of which is intended for start-up after the device has been dismantled and the shorter one for starting up after a short break in work. In the latter case there is still mass in the housing and it is only necessary to prevent excess fibers in the mixture for a short time when starting up. After an extended interruption, disassembly and cleaning of the device, on the other hand, the housing is empty when starting, and the running time of the mass from the storage container to the fiber addition point is taken into account.

The composition of the mass remains the same even after it has been switched off, and fiber material is saved, which is normally the most expensive component.

The device according to the invention can be provided with a safety circuit which monitors the water pressure and / or suitable operating parameters of a fiber cutting unit and switches off in the event of a malfunction.

• Figur 1 einen Längsschnitt der erfindungsgemäßen Vor­richtung;
• Figur 2 den Austrittsbereich eines Vorratsbehälters der Vorrichtung, ebenfalls im Längsschnitt;
• Figur 3 einen schematischen Querschnitt nach III-III von Figur 2;
• Figur 4 ein Mischwerkzeug der erfindungsgemäßen Vor­richtung in Seitenansicht;
• Figur 5 einen Schnitt nach V-V von Figur 4;
• Figur 6 eine Einzelheit eines Feinzerkleinerungsbe­reichs der Vorrichtung im Längsschnitt;
• Figur 7 zu der Vorrichtung gehörige Fasereinbauwerkzeu­ge in einer schematischen axialen Draufsicht auf einen Wellenabschnitt der Vorrichtung.

The invention is explained below with reference to an embodiment shown in the drawings. Show schematically:

• 1 shows a longitudinal section of the device according to the invention;
• Figure 2 shows the exit area of a storage container of the device, also in longitudinal section;
• 3 shows a schematic cross section according to III-III of Figure 2;
• Figure 4 shows a mixing tool of the device according to the invention in side view;
• 5 shows a section along VV of Figure 4;
• FIG. 6 shows a detail of a fine comminution area of the device in longitudinal section;
• Figure 7 belonging to the device fiber installation tools in a schematic axial plan view of a shaft section of the device.

The device shown in FIG. 1 has a housing with a substantially circular cylindrical tube 10 coming horizontally. At one end of the tube is the storage container 12 for dry substance, downstream of which there is a radial water connection 14, further downstream a fiber installation station with a fiber cutting device 16, and finally at the other end of the tube 10, a conically tapering end part 18, which has a discharge opening 20 towards the bottom. The device provides 10 fiber concrete in a continuous flow through the tube when using desiccant, water and fibers.

The device is mounted on rollers 22 in the region of the storage container 12 and is supported with a foot 24 against the ground. The fiber cutting mechanism 16 has a separate frame 28, which also runs on rollers 26. This structure enables a change of location to be carried out quickly and easily.

In the exemplary embodiment shown, the storage container 12 is designed as an attachment box, which can in particular be provided with a sack ripper. However, instead of an attachment box, a silo connection part can also be used, via which dry matter is fed directly from a silo to the device according to the invention. The conversion between the two variants is easy.

A motor 30 is attached to the reservoir 12 in the axial extension of the tube 10. This drives a shaft 32, which runs through the full length of both the reservoir 12 and, in a central, axial arrangement, the tube 10. The shaft 32 carries a number of tools, which are used for dosing dry material from the storage container 12, mixing, grinding, for fiber installation and last but not least for transporting the mass through the pipe 10.

FIG. 2 shows schematically how dry substance is discharged from the storage container 12. A section of the shaft 32 running inside the storage container 12 carries a metering screw 34 and individual, radially projecting loosening vanes 35. The shaft 32 is guided through a front-side outlet opening 36 of the storage container 12, which represents the transition to the tube 10. The outlet opening 36 has a circular cross section and has a smaller diameter than the tube 10, with respect to which it is arranged in the center. The cross-sectional constriction is formed by a cylinder sleeve 38, which is arranged coaxially to the tube 10 and protrudes radially inwards and has a length. The dosing screw 34 protrudes into the cylinder sleeve 38 in which it ends.

With the shaft 32 rotating, the dosing screw 34 transports dry material from the storage container 12 into the pipe 10 at a well-defined rate. The dosing rate depends on the structural geometry, in particular the size of the outlet opening 36 and the gradient of the dosing screw 34, the chamber volume and the speed of the shaft 32 from which it can be regulated within wide limits.

Referring to Figures 1 to 5, closes downstream a mixing zone from the dosing zone in the tube 10. Here, the shaft 22 carries mixing blades 40 projecting radially therefrom, which mix the material located in the tube 10 and, at the same time, transport it through its shape, a suitable angle of attack, etc. A part of the mixing blades is equipped with scrapers 42, 44 made of hard rubber or the like. exist and lie on the inner wall of the tube 10. In particular in FIGS. 4 and 5, wipers 42 can be seen, which are attached to the radially outer end of a pair of mixing blades 40 and which extend essentially in the axial direction. The mixing blades carry a flat part 41 serving as a holder, to which the wipers 42 are fastened with screws or rivets 43. A number of such mixing vane groups 40 with wipers 4 are provided, which follow the shaft 32 at a distance from one another in the axial direction (FIG. 1). The mixing blades 40 of the individual groups are angularly offset by 120 ° in the circumferential direction. At the level of each group there are also individual mixing blades 46 without wipers, and also at an angular offset of, for example, 120 °. This geometry is shown schematically in FIG. 3.

As can be seen in FIG. 2, one of the wipers 44 is located at the axial end of the cylinder bush 38, at which the passage cross section for the material widens to the inside dimension of the tube 10. The scraper 44 lies against both the end face 48 of the cylinder liner 38 and the inner wall of the tube 10. It thus ensures that the step-like transition to the outlet of the storage container 12 is always scraped free of material, which among other things promotes a well-defined separation of the wet zone and dry zone of the device according to the invention.

Referring to Figures 1 and 2, there is water port 14 of the device in the mixing zone, in its upstream part. The water connection 14 is at some distance from the diameter step at the end of the cylinder liner 38. It is also inclined against the pipe axis, so that a water jet fed in has a spray direction downstream in the conveying direction of the material. All of these measures, in particular the grading of the diameter of the housing of the device and the stripper 44 working there, prevent water from getting into the reservoir 12. This lock is particularly effective when the drive of the shaft is switched off and the flow of the material is interrupted. It is thus possible to interrupt the continuous production of mortar at short notice, for example for 10 to 15 minutes, and then to restart the device without having to take any special measures.

The wipers 42, 44 intensify the mixing process and ensure that the mixing zone extends over the full cross section of the tube 10. Furthermore, they also serve to support the shaft 32. As FIG. 1 shows, the shaft 32 is supported twice; a roller bearing 50 is provided as a second bearing on the end face of the conical tube end part 18.

A fine comminution zone of the device adjoins the mixing zone downstream. In this, the shaft 32 carries comb-like tools 52 which adjoin the shaft 32 with their comb back, extend essentially in the radial direction and have radially projecting pins. A plurality of combs 52 offset at an angle can be attached at the same axial height, for example three combs 52 at an angular distance of 120 °. The combs 52 rotating with the shaft 32 stand with combs fixed to the housing 54 engaged. The latter come to rest with their comb back on the inner wall of the tube 10, extend essentially in the axial direction, and have radially inwardly directed tines. The engagement of the combs 52, 54 according to the key-lock principle is illustrated in FIG. 6. With the shaft 32 rotating, the mass conveyed through the tube 10 is finely comminuted and homogenized between the combs 52, 54. It is lump-free, pasty and very free-flowing, making it ideally prepared for the installation of fibers. The combs 52, 54 are preferably made of steel wire. However, other materials, in particular plastic and hard rubber, can also be used.

The fiber addition point with the fiber cutting unit 16 follows downstream of the fine comminution zone. This is supplied with fiber strands 58, for example glass fiber rovings, which are cut to a predetermined length. The amount of fiber provided per unit of time can be regulated via the retraction speed of the fiber cutting unit 16. After being cut, the fibers enter a chute 56 which is oriented essentially vertically and opens into the tube 10 of the device.

The invention is not restricted to the use of glass fibers, in particular alkali-resistant glass fibers. For example, other mineral fibers, plastic fibers, steel fibers, etc. are processed.

The material conveyed by the device is taken up downstream of the combs 52, 54 by a spiral axial screw 60 which extends under the chute 56 and through the conical end part 18 up to the dispensing opening 20. The worm 60 sits on the shaft 32 and mix the material and the fibers. At the level of the chute 56, the shaft 32 is additionally equipped with pin-shaped fiber installation tools 62. As can be seen in FIG. 1, these pins 62 follow one another axially at a distance. They are further distributed over the circumference of the shaft 32, wherein, for example, three angularly offset pins 62 can be arranged at the same axial height. This is illustrated in Figure 7; the screw 60 is not shown for the sake of clarity. The pins 62 protrude essentially radially from the shaft 32, and they are curved in the circumferential direction, namely counter to the direction of rotation of the shaft 32. With these pins 62, the fibers are carefully and uniformly installed in the material.

Downstream of the chute 56, the conical pipe end part 18 tapers towards the discharge opening 20. The section of the screw 60 contained in this end part 18 tapers accordingly. This shape enables gentle, particularly intensive installation of the fibers.

The device according to the invention is segmented. The conical end part 18 is a removable part which is connected to the tube 10 via a quick-release fastener 64. The tube 10 is in turn attached to the reservoir 12 with a corresponding quick-release fastener, not shown. You can easily dismantle the housing of the device for cleaning purposes. The shaft 32 is in one piece at least from the mixing zone to the discharge opening 20. The shaft section in the interior of the storage container 12 can be a separate part on which the shaft 32 can be detachably fixed in a rotationally fixed connection.

The device according to the invention can be used with or without the addition of mixing water both for the production of fiber-reinforced hydraulically setting compositions and for other purposes. A first construction variant of the device includes the part that extends from the storage container 12 to just behind the fine comminution tools 52, 54. This unit alone is used for continuous dosing, mixing and fine grinding, alternatively for dry matter or a matrix made with water. In a second construction variant, the fiber installation part is also connected. The combined unit can also be used as an alternative to mixing dry material with fibers and incorporating fibers into a matrix made with water. A preferred area of application is the production of fiber concrete in a continuous mixing process.

Water is preferably added by means of a water pump 66 via a metering unit 68. From this the water reaches the water connection 14 via a line 70, in which a tap 72 and a pressure gauge 74 are located.

The device according to the invention has a control unit 76 with a time delay circuit which takes effect when the device is started up and switched off. When commissioning, the metering and mixing shaft 32 starts up with a lead relative to the fiber cutting unit 16. There are two different lead times that can be selected at the push of a button. A longer lead-up period of, for example, approximately 8 seconds is used when the device is started up for the first time, after dismantling and cleaning, etc., ie in an operating state with an empty pipe 10. This takes into account the fact that the dosage of the goods a certain runtime is required from the storage container 12 until the fiber addition point is reached. After a brief switch-off of the device, which is easily possible thanks to the separation of the drying zone and the wet zone, the shorter lead-in period of the metering and mixing shaft 32 relative to the fiber cutting unit 16 is selected, which can be, for example, approximately one second. When the device is switched off, the fiber cutting mechanism is always stopped first, while the shaft 32 continues to run for a short time, for example also about a second.

When producing a mixture mixed with water, the water supply is started at the same time as the metering and mixing shaft 32 starts. A safety circuit is provided which monitors the water pressure and prevents the device from operating when the water pressure is insufficient. Furthermore, the proper functioning of the cutting unit 16 is monitored so that there are no operational disturbances due to the drawing in of uncut fibers. The cutting unit 16 contains a roller, which presses the fiber strands pneumatically controlled against rotating cutting knives. If the pneumatic working pressure is insufficient, the system is switched off.

• 1. die Dosierung des Trockenstoffs (Fördern einer vorgegebenen Menge pro Zeiteinheit mit der Dosierschnecke),
• 2. die Dosierung von Wasser und die Herstel­lung der Naßmischung in dosierter Menge (vorgegebene Menge pro Zeiteinheit) mittels eines Durchlaufmischers;
• 3. das Unterziehen bzw. Untermischen bzw. Einbauen von Faserschnitzel, die in der Fasereinbauzone von einem Schneidwerk dosiert zugegeben werden.

A core idea of the invention is to perform various functions in succession by means of a shaft and a drive, in particular

• 1. the dosing of the dry substance (conveying a predetermined amount per unit of time with the dosing screw),
• 2. the dosing of water and the production of the wet mixture in a metered amount (predetermined amount per unit of time) by means of a continuous mixer;
• 3. the subjecting or mixing in or installing fiber chips, which are added in the fiber installation zone metered by a cutting unit.

The device according to the invention permits the continuous production of fiber concrete with an adjustable fiber content and predeterminable fiber length in a mixing process which delivers a steady stream of material with a constant and excellently reproducible composition. The material can be placed directly in molds, formwork, etc., for example to produce thin-walled moldings with high stability. Further areas of application are the production of cement-bound pipe coatings, fiber plasters, floor coverings, etc. Finally, building renovation offers a variety of possible uses.

List of reference numbers

• 10 pipe
• 12 storage containers
• 14 water connection
• 16 fiber cutting unit
• 18 pipe end part
• 20 dispensing opening
• 22 roll
• 24 feet
• 26 roll
• 28 frame
• 30 engine
• 32 wave
• 34 dosing screw
• 35 loosening blades
• 36 outlet opening
• 38 cylinder liner
• 40 mixing blades
• 41 flat part, holder
• 42 wipers
• 43 screw, rivet
• 44 wipers
• 46 mixing blades
• 48 end face
• 50 rolling bearings
• 52 comb
• 54 comb
• 56 chute
• 58 fiber strand
• 60 snail
• 62 pen
• 64 quick release
• 66 water pump
• 68 dosing unit
• 70 line
• 72 cock
• 74 pressure gauge
• 76 control unit

Claims (19)

1. Device for the continuous provision of hydraulically setting compound, in particular wet mortar or dry mortar, preferably with a proportion of fibers, with a housing which has a charging point and an outlet opening (20), and with a shaft which is driven and rotates therein and causes a flow through the housing (32), which is equipped with tools arranged one behind the other in the conveying direction for metering (34) mixing (40, 46, 60), fine comminution (52, 54) and optionally for installing fibers (60, 62). 2. Apparatus according to claim 1, characterized in that the housing is substantially cylindrical-tubular (10) and optionally conical in places (18), and that the shaft (32) is received centrally and axially in the housing (10) and is preferably mounted twice . 3. Apparatus according to claim 1 or 2, characterized in that the housing is divided into sections which are preferably connectable with a quick release (64). 4. Device according to one of claims 1 to 3, characterized in that a storage container (12) is provided at the loading point, for example in the form of a top box or silo connection, and that a shaft section projecting into the storage container (12) has a metering screw (34) wearing. 5. The device according to claim 4, characterized in that the housing in the outlet region (20) of the storage container (12) has a preferably central cross-sectional constriction through which the shaft (32) with the metering screw (34) protrudes. 6. Device according to one of claims 1 to 5, characterized in that the shaft (32) downstream of the metering screw (34) carries radially projecting mixing blades (40, 46), at least some of which are employed at an angle to the conveying direction can be. 7. The device according to claim 6, characterized in that the mixing blades (40) with the abutting against the inner tube wall and / or the end face (48) of the cross-sectional wipers (42, 44) are equipped, which extend in particular in the axial direction and to the Tips of a pair of mixing blades (40) can be attached. 8. Device according to one of claims 1 to 7, characterized in that the housing in the region of the motor-side mixing zone has a peripheral water connection (14) with preferably at least slightly downstream spray direction. 9. Device according to one of claims 1 to 8, characterized in that the shaft (32) downstream of the mixing blades (40, 46) carries at least one comb (52) with at least one housing-arranged further comb (54) for fine comminution of the mix is engaged. 10. The device according to claim 9, characterized in that the combs (52, 54) extend in the axial direction and have substantially radially directed pins. 11. The device according to claim 9 or 10, characterized by a plurality of combs (52, 54) which are preferably offset at the same angular distance in the circumferential direction. 12. Device according to one of claims 1 to 11, characterized in that there is a fiber input point downstream of the fine comminution zone with a chute (56) opening into the housing, and that the shaft (32) in the region of the chute (56) is a spiral -Axial worm (60) and optionally carries at least one further fiber installation tool. 13. The apparatus according to claim 12, characterized in that a number of substantially radially projecting from the shaft (32) as a fiber installation tool pins (62) are preferably provided in the circumferential direction counter to the direction of rotation of the shaft (32). 14. Device according to one of claims 1 to 13, characterized in that the chute (56) is arranged upstream of a fiber cutting mechanism (16) which is preferably controllable with respect to the amount of fiber and / or fiber cut length supplied. 15. The device according to one of claims 1 to 14, characterized in that the housing tapers downstream from the chute (56) to the dispensing opening (20) and has a correspondingly conically tapering screw section (60) seated on the shaft (32) ) contains. 16. A method of operating and controlling the device according to one of claims 1 to 15, characterized in that the shaft (32) is started with a lead in relation to the fiber addition and is stopped with a lead in relation to the fiber addition. 17. The method and control unit according to claim 16, characterized by two selectable lead periods of the shaft (32), one of which is longer for the start-up and the other shorter for starting after a short-term interruption. 18. Control unit according to claim 16 or 17, characterized by a safety device, the water pressure and / or suitable operating parameters, for example. monitors the pneumatic operating pressure of the fiber cutting unit (16). 19. Production of fiber concrete in a continuous mixing process, in particular with a device according to one of claims 1 to 18.

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