ES3041443T3 - Apparatus for spraying concrete - Google Patents

Abstract

The present application relates to a device 1 for spraying concrete, comprising the following features: a) a conveying line 2, which is configured and designed to receive concrete from an inlet end 5 and convey it to its outlet end 6; b) a lance 13, which is configured and designed to discharge the concrete by spraying; c) the lance 13 has an inlet end for the concrete supplied by the conveying line 2 and a water supply 7 adjacent to this inlet end, wherein the water supply 7 is configured and designed to introduce water into the lance 13 so that the concrete mixes with the water in the lance 13 and the flowability of the concrete within the lance 13 is increased; f) a binder supply 9 is connected to the lance 13 at a distance from the water supply 7 in the direction of flow of the concrete, wherein the binder supply 9 is configured and designed to introduce a binder into the water-enriched concrete; g) at a distance from the binder supply 9 An air supply 11 is connected to the lance 13, which is designed and configured to form an annular airflow 12 that determines the size of a spray cone of concrete emerging from the lance 13. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Device for projecting concrete

The invention relates to a device for projecting concrete according to the features of claim 1.

Blast furnace channels are lined with refractory material, which is subject to constant wear and requires continuous repair. This repair is carried out, for example, using shotcrete. Shotcrete sets immediately upon contact with the hot channel lining. Therefore, the technology needed to apply shotcrete is often already available within a blast furnace.

A mixer is typically used to prepare shotcrete by blending. The mixer is charged with a fine-grained material to produce a fluid mass. This fluid mass is then conveyed from the mixer to a concrete pump. The concrete pump usually conveys the material through a double-piston system to a delivery hose. The delivery hose is typically 120 mm in diameter, making it very difficult to handle. Operating the system requires a relatively large number of personnel. One person has to start the concrete mixer, another the pump, and two people have to carry the relatively heavy hose with the nozzle. The work is physically demanding and strenuous.

Another disadvantage of this system is the relatively high water consumption for cleaning the machine. Concrete is always lost during cleaning, as the pump, mixer, and, of course, the delivery hoses all need to be cleaned. On average, around 300 kg of concrete are wasted. Besides the concrete losses, the cost of the equipment required for this type of shotcrete application is relatively high.

With regard to the prior art, reference is made to WO 98/40168 A1, which describes a device for spraying concrete. A conveying pipe is configured and designed to receive concrete from an inlet end and convey it to its outlet end. A spray gun is used to apply the concrete by spraying. It has an inlet end for the concrete fed by the conveying pipe and a water supply adjacent to this inlet end. The water supply is configured and designed to introduce water into the gun so that the concrete mixes with the water in the gun and increases the fluidity of the concrete within the gun. In the direction of concrete flow and at a distance from the water supply, a binder supply is connected to the gun, configured and oriented to introduce a binder into the water-enriched concrete. Finally, there is an air supply in the gun at a distance from the binder supply. It is configured and designed to create an airflow that is directed at least partially radially toward the material flow through nozzles arranged in an annular pattern. Specifically, it is compressed air that is controlled by the operator to achieve optimal spraying results, particularly to accelerate the material before it exits the connected lance nozzle.

EP 3431172 A1 discloses a nozzle for spreading concrete, the nozzle having an additional opening for an additive, specifically a setting accelerator. Such a nozzle is used for 3D printing. The process is configured so that the concrete begins to harden within the nozzle. Thanks to a thin mixing tube, the concrete can be spread homogeneously, precisely, and accurately from the nozzle. Furthermore, concrete can be blown into the nozzle with compressed air, allowing for controlled material discharge.

With regard to the state of the art, reference is also made to document FR 2798092 B1 as well as to document WO 2017021259 A1.

The invention is based on the objective of showing a device for projecting concrete that is much easier to handle and, in particular, that can be operated more economically.

The invention achieves this objective by means of a device with the characteristics of claim 1.

Dependent claims relate to advantageous improvements of the invention.

The device according to the invention for injecting concrete comprises, firstly, a conveying conduit configured and designed to receive concrete from an inlet end and convey it to its outlet end. The concrete is fed into a lance, which is itself configured and designed to apply the concrete by spraying. The particular advantages of the invention derive in particular from the configuration of the lance. The lance has an inlet end for the concrete fed by the conveying conduit and a water supply adjacent to this inlet end. The water supply is configured and designed to introduce water into the lance in such a way that the dry concrete mix is blended with the water in the lance, increasing the fluidity of the concrete within the lance.

Because water is only supplied to the concrete mix at the nozzle, the concrete mix in the delivery hose is drier and therefore considerably lighter before reaching the water supply. This also makes the nozzle easier to handle manually. A dry refractory material, typically conveyed by a pneumatic conveyor, can be used as the concrete mix. It is not absolutely necessary to use a completely dry refractory material; a relatively dry or only slightly damp concrete mix is sufficient. This relatively dry concrete mix, referred to as dry concrete from now on, is conveyed by air from the pneumatic conveying system to the nozzle.

In the lance area, a binder supply is located at a distance from the water supply. This binder supply is configured and designed to introduce a binder into the water-enriched concrete. Soluble glass or potassium silicate, for example, can be used as binders. This mixture, prepared only shortly before the actual discharge, can then be spread. The binder is also supplied relatively late, allowing the dry concrete in the conveying pipe to be particularly dry. It does not need to transport binder or water in the quantities required for setting. This makes it possible to equip the conveying pipe and lance with a relatively small cross-section, for example, less than 50 mm, particularly 45 mm. The lance is thus significantly lighter than a conveying pipe with a 120 mm cross-section, which is also filled with a wet concrete mix. In this way, the spear can be held and operated by a single person, which is a significant handling advantage.

Furthermore, as a special feature, the lance has an air supply that should not be confused with an air supply for transporting the concrete mix. This air supply is configured and designed to create an annular airflow that determines the size of the spray cone of concrete exiting the lance. This allows for the processing of classic refractory liquid concrete in a particularly specific way. The annular airflow, which can also be called an air ring, acts as a nozzle sleeve surrounding the material flow.

A key advantage of the invention is that no costs are incurred in developing a new, specially formulated shotcrete. Conventional refractory liquid concrete can be used and sprayed with the device according to the invention. Furthermore, preparing the concrete mix is significantly simpler. There is no need for a twin-piston pump or a mixer. Less personnel are required. There is no need to transport or install the necessary equipment. With fewer installation components, there are fewer hoses, and cleaning is less effort.

Another advantage is that there is no concrete loss. The finished mix is produced only shortly before exiting the nozzle. This significantly reduces water consumption for cleaning the conveyor, especially since the dry concrete is only pneumatically conveyed in the conveyor line. The high air content in the conveyor line reduces the weight of the conveyor line per meter.

Another advantage is that no complex site preparation is required. In blast furnace areas, a concrete conveyor is always present. It is used for repairing channels with a special shotcrete. However, compared to this special shotcrete, liquid concrete has the advantage of being denser and of higher quality. The denser the channel wall, the less slag and iron can penetrate it and cause wear. The concrete is generally applied to the hot channel and hardens immediately. The less water in the concrete mix, the faster it will harden.

Another advantage of the invention is that channel wall formwork can be dispensed with. When formwork is dispensed with, stripping can also be eliminated. With this invention, intermediate repairs to the channel are therefore also possible quickly and easily. Downtime in the blast furnaces can be significantly reduced.

The device according to the invention is also particularly suitable for projecting coarse-grained material with a grain size of up to 19 mm. Material of this grain size cannot be processed using twin-piston pumps because they would become clogged. The very low water content of the material leads to higher density and, therefore, also to higher quality canal improvement work.

At one end of the nozzle, a nozzle ring is arranged, configured and designed to form an annular airflow surrounding the flow of concrete material exiting the nozzle. To this end, the nozzle ring may consist of several individual nozzles. The individual nozzles may also be axially oriented openings in a circular annular plate. According to the invention, a nozzle ring is also an axially open annular space with a single circular ring-shaped opening from which an annular airflow emerges to surround the material flow. The annular opening may preferably have a separation width of 2 to 6 mm, particularly 3 to 5 mm, measured radially with respect to the nozzle.

In an improvement of the invention, the nozzle ring protrudes a length beyond the outlet end for the concrete to be sprayed. The airflow is directed on the outside of the nozzle ring. In particular, the nozzle ring protrudes a length greater than the diameter of the spray lance. In the case of a lance with a diameter of 40 mm, the length of the nozzle ring before the outlet end is 50 to 100 mm, preferably 60 to 80 mm. The nozzle ring is fixed to the lance and thus also surrounds an end zone of the lance before the outlet end. This end zone is preferably at least as long as the length of the nozzle ring before the outlet end. The technical effect of this is that a cylindrical tube with a slightly larger diameter than the lance can be used as the nozzle ring. Within the sufficiently long annular space between the outer side of the lance and the inner side of the nozzle ring, a homogeneous, axially oriented annular airflow can be generated along the entire circumference of the nozzle ring, guiding the discharged material. This annular airflow is axially oriented and does not point towards the outgoing material flow. The airflow envelops the material flow, thus concentrating the spray and contributing extremely effectively to guiding the material flow. The annular airflow preferably has a constant diameter in the flow direction, directly adjacent to the material flow. The connected airflow preferably has a pressure of approximately 500 to 600 kPa (5 to 6 bar).

In an improvement of the invention, a nozzle ring is arranged at one end of the lance, adjustable along the lance's length. The nozzle ring is designed and configured to adjust the size of the concrete spray cone. The further the nozzle ring is retracted toward the lance, the larger the spray cone becomes. As the nozzle ring slides further forward, the concrete spray cone decreases.

The air supply is advantageously used to form an annular airflow in the annular space between the nozzle ring and the lance, so that the spray cone size can be controlled simply by controlling the airflow, even without adjusting the nozzle ring.

In an improvement of the invention, the annular space has several openings distributed along its circumference, through which it is connected to an air distribution chamber that borders the annular space. The openings can be holes with a diameter of 3 to 10 mm, arranged radially along the circumference, for example, at an angular distance of 30° to 60°. The openings are located at a distance from the outlet end of the lance, so that the air in the annular space is first distributed uniformly and then deflected toward the outlet end to form the desired annular airflow.

The airflow effect is such that the concrete flows through the nozzle ring without touching it. When the airflow is interrupted, the liquid concrete will flow from the nozzle ring instead of being projected. The airflow is essential for transporting concrete beyond the nozzle's discharge end. The airflow that guides the concrete through the nozzle to the discharge end serves solely for transport to and within the nozzle.

In an improvement of the invention, the water supply is designed in an annular configuration so that the water can be distributed evenly to the concrete along its circumference. Therefore, the water supply is preferably an annular nozzle arrangement with several water outlets arranged along the circumference of the flow channel. As a result of the uniform water supply, the dry concrete mix is moistened as evenly as possible and bonded to the concrete.

The binder is supplied in the flow direction at a distance from the water supply. In an advantageous refinement of the invention, the binder supply is also designed in an annular fashion, so that the binder can also be supplied, distributed along the circumference, to the concrete previously mixed with water. The distance between the binder supply and the water supply can be from 50 cm to 2 m. The mixing section only needs to be long enough to allow the water to mix thoroughly with the relatively dry concrete mix and, finally, for the binding agent to be absorbed uniformly.

The nature of the finished concrete mix depends largely on the water and binder supply. The supply can be regulated by valves. In an advantageous improvement, these valves for opening and closing the water, binder, and air supply are located directly on the spray gun. The gun operator can precisely control the three valve positions and readjust them during concrete placement to achieve the optimal mix design.

In an improvement of the invention, the water supply valve and the binder supply valve are arranged side by side at a distance of less than 30 cm, so that a sprayer operator only needs one hand to operate both valves while holding the sprayer with the other. The device according to the invention is designed to be operated by a single person. When the valves required for operation are very close together, the concrete spraying can continue while the operator adjusts or selects the valve positions to establish the correct mix ratio.

In an improvement to the invention, the air supply valve is further arranged less than 30 cm from the other valves, so that a lance operator only needs one hand to operate the valves while holding the lance with the other. This concept is also based on the single-person operation of the device, and in particular the lance. For ergonomic reasons, all the adjustments required to operate the lance or the projectile device can be minimized so that the operator can always hold the lance with one hand and does not have to interrupt their work when the valves are operated.

In another advantageous improvement, the invention provides that the water supply valve, the binder supply valve, and the air supply valve can be operated by a single common actuating lever. The three gas and liquid flows can be stopped and started via this common actuating lever, functioning as a start-stop circuit. The respective valve positions can preferably be adjusted independently of each other to achieve the desired mixing ratio. The respective valve position can be adjusted independently of the actuating lever.

For single-person operation of the device according to the invention, it is advantageous when the lance has a cross-sectional area of less than 50 mm, so that the lance can be carried and operated by a single person. The cross-sectional area of less than 50 mm is also preferably continued in the transport channel. The lance preferably has a diameter of 40 mm to 45 mm.

The lance according to the invention is configured and designed specifically for spreading refractory concrete, particularly for applying it to a hot tapping channel of a melting furnace. As mentioned above, the concrete used is, in particular, dry concrete that can be conveyed within the conveying pipe by means of air. The grain size is not limited. In combination with a pneumatic rotor injection machine, which can be used to introduce the concrete into the conveying pipe, dry concrete with a grain size of up to 19 mm can be processed.

In an advantageous refinement of the invention, the rotor projection machine comprises a remote control for starting and stopping with respect to the concrete to be transported and the transport air for transporting the concrete, the remote control being arranged in the area of the valves for water supply, binder supply and air supply.

In an improvement of the invention, the remote control and the valves can be operated by means of a common actuating element.

With the device according to the invention, it is possible to spread shotcrete with significantly less personnel and at lower equipment costs. Concrete loss due to cleaning the device according to the invention is also significantly lower compared to the prior art.

The invention is explained in more detail below by means of exemplary embodiments, which are represented schematically in the drawings. They show:

Figure 1 shows a device for projecting concrete, and

Figure 2 A nozzle ring for an alternative device for projecting concrete.

Figure 1 shows a device 1 for projecting concrete with a transport conduit 2 in the form of a flexible transport hose. The transport hose preferably has a diameter less than 50 mm, in particular a diameter of 45 mm.

A dry concrete mix 3 is pneumatically introduced into an inlet end 5 of the conveying line 2 by a rotor spraying machine 4 and conveyed to its outlet end 6. Following the outlet end 6 is a water supply 7, which is designed and configured to introduce water into a mixing section 8 that follows the flow direction of the concrete mix 3. The water supply 7 is designed in an annular shape so that the water can be distributed around the circumference of the concrete. Several water inlet points are symbolically represented in the water supply area 7. This is an annular arrangement surrounding the mixing section 8.

In the flow direction, at a distance from the water supply 7, there follows an annular binder supply, for example, for the supply of silicate or soluble glass. Here too, several inlet openings are shown as an example so that the concrete mix, previously mixed with water, can also be uniformly moistened with the binders. The binder supply 9 is followed by an additional mixing section 10 and, finally, an annular air supply 11. The air supply 11 generates an annular airflow 12 between an outer sleeve of the lance 13 and a nozzle ring 14 that can be adjusted in the longitudinal direction of the lance 13. Depending on the position of the nozzle ring 14 with respect to the lance 13 or with respect to the intensity of the airflow 12, the size of the concrete spray cone can be influenced.

Figure 1 shows that valves 15, 16, and 17 for the water, binder, and air supplies are arranged relatively close together, specifically in this case, in the binder supply area 9. The binder supply 9 is located approximately in the central area between the upstream mixing section 8 and the downstream mixing section 10 in the flow direction. Valves 15, 16, and 17 are arranged so that they can be easily operated by a single person carrying the lance 13. The distance between valves 15, 16, and 17 is preferably less than 30 cm. The actuators of valves 15, 16, and 17 can be combined so that all three substance flows can be operated with a single lever. Additionally, the air and material supply to the rotor 4 projector machine can also be controlled by a remote control 18 for the rotor 4 projector machine.

Figure 2 shows an alternative embodiment of a spear 13, maintaining the reference numbers used in Figure 1 for functionally identical components.

The front end of the nozzle 13 is shown in longitudinal section. The nozzle 13 extends to its outlet end 22, where the concrete mix 3 exits as a material flow M, in accordance with the central arrow drawn. The air supply 11 is shown on the nozzle 13. The air supply 11 comprises a ring of nozzles 14. This is a circular cylindrical tube with a diameter slightly larger than that of the nozzle 13, defining an annular space 21 with the nozzle 13. The annular space 21 is a narrow slit with width S1. In this case, the width S1 is 3 mm. The diameter D1 of the nozzle 13 is 40 mm. The annular space 21 is open towards the outlet end 22 of the concrete mix 3 from the nozzle 13. Its other axial end is closed. The annular space 21 is surrounded by an air distribution chamber 19 along its entire circumference. An air duct 24 is radially connected on the outside to the air distribution chamber 29 for air supply. Openings 24 are distributed along the inner circumference of the air distribution chamber 19. Through these openings 24, air flows uniformly from the air distribution chamber 19 radially from all sides into the annular space 21. In the annular space 21, the air is deflected axially, generating a purely axially oriented airflow 12 at the outlet end 22, which runs parallel to the material flow M. The airflow 12 is not directed at the material flow M; that is, there are no means in the nozzle ring 13 that cause the airflow to form an acute angle with the material flow.

The airflow 12 is directed beyond the outlet end 12 by the nozzle ring 14, the nozzle ring 14 extending beyond the outlet end 12. This cylindrical end section 23 of the nozzle ring 14 has a length L1 which is greater than the diameter D1 of the lance 13. In this case, it amounts to 70 mm.

Airflow 23 flows along the inner side 25 of the end section 23 parallel to the material flow M. The material flow M is completely enveloped by the parallel-guided airflow 12. The airflow 12 is not directed towards the material flow M.

Reference symbols:

1- Device for projecting concrete

2- Transport driving

3- concrete mix

4- rotor projector machine

5- 2-inlet end

6- 2-outlet end

7- water supply

8- mixing section

9- supply of binder

10- mixing section

11 - air supply

12- airflow

13- spear

14- nozzle ring

15- water supply valve

16- valve for binder supply

17- air supply valve

18- Remote control for 4-rotor projector machine

19- air distribution chamber

20- opening

21 - annular space

22- 13-outlet end

23- end section of 14

24- air conduction

25- inner side of 14

D1- diameter of 13

L1 - length of 23

M- material flow of 3

S1- width of 21

Claims (13)

1. Device (1) for projecting concrete, with the following characteristics: a) a transport conduit (2) that is configured and designed to receive concrete from an inlet end (5) and convey it to its outlet end (6), b) a lance (13) that is configured and designed to spread the concrete by projection; c) the lance (13) has an inlet end for the concrete fed by the transport conduit (2) and a water supply (7) adjacent to this inlet end, wherein the water supply (7) is configured and designed to introduce water into the lance (13) so that the concrete is mixed with the water in the lance (13) and the fluidity of the concrete within the lance (13) is increased; d) in the flow direction of the concrete, at a distance from the water supply (7), a binder supply (9) is connected to the lance (13), wherein the binder supply (9) is configured and designed to introduce a binder into the water-enriched concrete; e) at a distance from the binder supply (9), an air supply (11) is connected to the lance (13), which is configured and designed to form an annular airflow (12) that determines the size of a spray cone of the concrete coming out of the lance (13); f) at one outlet end (22) of the lance (13) there is a nozzle ring (14) that is configured and designed to form the annular airflow (12) surrounding the material flow (M) of the exiting concrete, wherein the air supply (11) is configured and designed to introduce air into an annular space (21) between the nozzle ring (14) and the lance (13), characterized in that In the annular space (21), the air is deflected in an axial direction so that an airflow (12) is generated that is purely axially oriented at the outlet end (22), which is conducted parallel to the material flow (M). 2. Device according to claim 1, characterized in that the lance protrudes a length (L1) with respect to the exit end (22). 3. Device (1) according to claim 1 or 2, characterized in that the nozzle ring (14) is adjustable in the longitudinal direction of the lance (13) and is designed and configured to adjust the size of the concrete spray cone. 4. Device (1) according to claim 3, characterized in that the annular space (21) is connected by means of several openings (20) distributed along its circumference to an air distribution chamber (19) that borders the annular space (21). 5. Device (1) according to any one of claims 1 to 3, characterized in that the lance (13) has valves (15, 16, 17) to open and close the water supply (7), the binder supply (9) and the air supply (11). 6. Device (1) according to claim 5, characterized in that the valve (15) for the supply of water (7), the valve (16) for the supply of binder (9) and the valve (17) for the supply of air (11) can be actuated by means of a single common actuating lever. 7. Device (1) according to any one of claims 1 to 6, characterized in that the lance (13) has a cross-sectional area of less than 50 mm, so that the lance (13) can be carried and operated by a single person. 8. Device (1) according to any one of claims 1 to 7, characterized in that the lance (13) is configured and designed to spread refractory concrete. 9. Device (1) according to any one of claims 1 to 8, characterized in that the concrete transported through the transport conduit (2) is dry concrete that can be transported with air inside the transport conduit (2). 10. Device (1) according to any one of claims 1 to 9, characterized in that it is designed and configured to project dry concrete with a grain size of up to 19 mm. 11. Device (1) according to any one of claims 1 to 10, characterized in that the concrete can be introduced into the transport conduit (2) by means of a pneumatic rotor projection machine (4). 12. Device (1) according to claim 11, characterized in that the rotor projection machine (4) has a remote control (18) for start-stop with respect to the concrete to be transported and the transport air, wherein the remote control (18) is arranged in the area of the valves for the supply of water (7), the supply of binder (9) and the supply of air (11). 13. Device (1) according to claim 12, characterized in that the remote control (18) and the valves (15, 16, 17) can be actuated through a common actuating element.