DEVICE FOR SPRAYING CONCRETE

Description

[0001] The invention relates to a device for spraying concrete according to the features of claim 1.

[0002] Blast furnace runners are lined with refractory linings that are subject to constant wear and tear and require continuous repair. This repair is achieved, for example, with shotcrete. The shotcrete sets immediately upon contact with the hot runner lining. Therefore, the necessary technology for applying shotcrete is usually available in the blast furnace area.

[0003] Typically, a mixer is used to mix the shotcrete. The mixer is fed with a fine-grained material to create a flowable mass. This flowable mass is then transported from the mixer to a concrete pump. The concrete pump typically conveys the material into a delivery hose using a dual-piston system. The delivery hose often has a diameter of 120 mm, making it very heavy to handle. Operating the system requires a relatively large number of personnel. One person must start the concrete mixer, another person operate the pump, and two people must carry the relatively heavy hose with the nozzle. The work is physically demanding and labor-intensive.

[0004] Another disadvantage of this system is the relatively high water consumption for cleaning the machine. Concrete loss is always incurred during cleaning, as both the pump and the mixer, and of course the delivery hoses, must be cleaned. On average, approximately 300 kg of concrete is generated, which must be disposed of. Aside from the concrete loss, the equipment required for this type of sprayed concrete application is also relatively high.

[0005] Regarding the prior art, reference is made to WO 98 / 40168 A1, which discloses a device for spraying concrete. A delivery line is designed and configured to receive concrete from an inlet end and to direct it to its outlet end. A lance serves to discharge the concrete by spraying. It has an inlet end for the concrete supplied from the delivery line and a water supply adjacent to this inlet end. The water supply is designed and configured to introduce water into the lance so that the concrete mixes with the water in the lance and increases the flowability of the concrete within the lance. A binder supply is connected to the lance in the direction of concrete flow and at a distance from the water supply, wherein the binder supply is designed and configured to introduce a binder into the water-enriched concrete.Finally, an air supply is located on the lance at a distance from the binder supply. It is designed and constructed to generate an air flow that is directed into the material flow via annularly arranged nozzles, at least partially radially oriented. This air flow is, in particular, compressed air, which is controlled by the operator to achieve the optimal spraying result, in particular to accelerate the material before it exits the connected lance nozzle.

[0006] EP 3431172 A1 discloses a nozzle for dispensing concrete, wherein the nozzle has an additional opening for an additive, in particular for a setting accelerator. Such a nozzle is used for 3D printing. The process is designed so that the concrete begins to harden already in the nozzle. Thanks to a thin mixing tube, concrete can be dispensed from the nozzle homogeneously, precisely, and with pinpoint accuracy. In addition, concrete can be blown out of the nozzle using compressed air, allowing the material discharge to be operated with compressed air as required.

[0007] For the state of the art, reference is also made to FR 2798092 B1 and WO 2017021259 A1.

[0008] The invention is based on the object of providing a device for spraying concrete which is considerably easier to handle and, in particular, can be operated more cost-effectively.

[0009] The invention solves this problem by a device having the features of claim 1.

[0010] The subclaims relate to advantageous developments of the invention.

[0011] The device according to the invention for spraying concrete initially comprises a delivery line which is set up and designed to receive concrete from an inlet end and to direct it to its outlet end. The concrete is fed to a lance, which in turn is set up and designed to discharge the concrete by spraying. The particular advantages of the invention arise in particular from the design of the lance. The lance has an inlet end for the concrete supplied from the delivery line and a water supply adjacent to this inlet end. The water supply is set up and designed to introduce water into the lance so that the dry concrete mix mixes with the water in the lance and the flowability of the concrete in the lance is increased.

[0012] Because the water is only added to the concrete mix in the lance, the concrete mix in the delivery hose is drier and therefore considerably lighter until it reaches the water inlet. This also makes the lance easier to handle manually. A dry refractory mass can therefore be used as the concrete mix, which is usually transported using a pneumatic conveyor. It is not absolutely necessary to use a completely dry refractory mass. It is sufficient to use a relatively dry or only slightly moist concrete mix. This relatively dry concrete mix, which will subsequently be referred to as dry concrete, is transported by air from the pneumatic conveying source towards the lance.

[0013] In the area of ​​the lance, at a distance from the water inlet, there is a binder inlet. The binder inlet is designed and constructed to introduce a binder into the water-enriched concrete. Water glass or potassium silicate, for example, can be used as a binder. This mixture, which is only prepared shortly before the actual discharge, can then be applied. The binder is also added at a relatively late stage, which means that the dry concrete in the delivery line can be particularly dry. It does not have to transport binder or water in the quantities required for setting. This makes it possible to equip the delivery line and the lance with a comparatively small cross-section, for example less than 50 mm, and in particular with a cross-section of 45 mm. The lance is therefore considerably lighter than a delivery line with a cross-section of 120 mm, which is also filled with a wet concrete mix.This means that the lance can be held and operated by just one person, which is a significant handling advantage.

[0014] Another special feature of the lance is its air supply. This is not to be confused with an air supply for conveying the concrete mix, but is designed and constructed to create an annular air flow that determines the size of the spray cone of concrete emerging from the lance. This allows for the particularly targeted application of traditional refractory cast concrete. The annular air flow, which can also be referred to as an air ring, acts like a nozzle jacket surrounding the material flow.

[0015] A key advantage of the invention is that no costs are required for the development of a new type of special shotcrete. Conventional, refractory cast concrete can be used to apply it, i.e., to spray it, with the device according to the invention. Furthermore, the preparation of the concrete mix is ​​significantly easier. No double-piston pump or mixer is required. Fewer personnel are required. The corresponding equipment does not need to be transported and installed. Fewer system components mean fewer hoses and less cleaning effort.

[0016] Another advantage is that there is no concrete waste. The finished mix is ​​prepared just before exiting the lance. This also significantly reduces water consumption for cleaning the conveyor, especially since the dry concrete is conveyed pneumatically in the conveyor line. The high air content in the conveyor line reduces the weight of the conveyor line per meter.

[0017] Another advantage is that no complex site preparation is required. A concrete conveyor is usually always present in blast furnace areas. It is used to repair the chute using a special gunite. However, poured concrete has the advantage over this special gunite in that it is denser and of higher quality. The more densely the chute wall is lined, the less slag and iron can penetrate the wall and cause wear. The concrete is usually applied to the hot chute and hardens immediately. The less water the concrete mix contains, the faster the concrete hardens.

[0018] A further advantage of the invention is that it eliminates the need for formwork for the trough wall. If formwork is eliminated, stripping is also eliminated. The invention therefore also allows for quick and easy interim repairs to the trough. Blast furnace downtimes can be significantly reduced.

[0019] The device according to the invention is particularly suitable for spraying coarse-grained material with a grain size of up to 19 mm. Material of this grain size cannot be processed using double-piston pumps because they would block the pump. The very low water content of the material leads to a higher density and thus also to a higher quality of the improvement work on the channel.

[0020] At an outlet end of the lance, a nozzle ring is arranged, which is designed and constructed to form the annular air stream that surrounds the material stream of concrete exiting the outlet end of the lance. For this purpose, the nozzle ring can have several individual nozzles. The individual nozzles can also be axially oriented openings in a circular ring plate. A nozzle ring within the meaning of the invention is also an axially open annular space with a single circular opening from which an air stream exits in a ring shape to surround the material stream. The annular opening can have a gap width, measured in the radial direction to the lance, of preferably 2 to 6 mm, in particular 3 to 5 mm.

[0021] In a further development of the invention, the nozzle ring protrudes by a length beyond the outlet end for the concrete to be sprayed. The air flow is guided externally by the nozzle ring. In particular, the nozzle ring protrudes by a length that is greater than the diameter of the lance. For a lance with a 40 mm diameter, the length of the nozzle ring in front of the outlet end is 50 to 100 mm, preferably 60 to 80 mm. The nozzle ring is attached to the lance and therefore also surrounds an end region of the lance in front of the outlet end. This end region is preferably at least as long as the length of the nozzle ring in front of the outlet end.The associated technical effect is that a cylindrical tube can be used as the nozzle ring, which is slightly larger in diameter than the lance, and that in the sufficiently long annular space between the outside of the lance and the inside of the nozzle ring, an axially oriented annular air flow that is homogeneous over the entire circumference of the nozzle ring and guides the material to be discharged can be generated. The annular air flow is axially oriented and does not point into the flow of the escaping material. The air flow surrounds the material flow, thereby focusing the jet and contributing extremely effectively to guiding the material flow. The annular air flow preferably has a constant diameter in the direction of flow, which is directly adjacent to the material flow. The connected air flow preferably has a pressure of approximately 5 to 6 bar.

[0022] In a further development of the invention, a nozzle ring is arranged at an outlet end of the lance, which is adjustable in the longitudinal direction of the lance. 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. If the nozzle ring is pushed further forward, the size of the concrete spray cone decreases.

[0023] Advantageously, the air supply is used to form an annular air flow in the annular space between the nozzle ring and the lance, so that the size of the spray cone can be controlled by controlling the air flow alone, even without adjusting the nozzle ring.

[0024] In a further development of the invention, the annular space has a plurality of openings distributed around its circumference, via which it is connected to an air distribution chamber adjacent to the annular space. The openings can be bores with a diameter of 3 to 10 mm, which are arranged in a radial plane distributed around the circumference, e.g., at an angular spacing of 30° to 60°. The openings are located at a distance from the outlet end of the lance such that the air is initially evenly distributed in the annular gap and then deflected towards the outlet end to form the desired annular air flow.

[0025] The air flow is designed to ensure that the concrete flows through the nozzle ring without touching it. If the air flow is interrupted, the poured concrete would flow out of the nozzle ring rather than being sprayed. The air flow is essential for transporting the concrete past the outlet end of the lance. The air flow that carries the concrete through the lance to the outlet end serves only to transport it to and within the lance.

[0026] In a further development of the invention, the water supply is designed in a ring shape so that the water can be supplied to the concrete in a distributed manner around the circumference. Therefore, the water supply is preferably an annular nozzle arrangement with several water outlets arranged around the circumference of the flow channel. The uniform water supply ensures that the dry concrete mix is ​​wetted as evenly as possible and bonds with the concrete.

[0027] The binder is fed in at a distance from the water supply, in the direction of flow. In an advantageous development of the invention, the binder feed is also ring-shaped, so that the binder can also be fed into the concrete, which has previously been mixed with water, distributed around the circumference. The distance between the binder feed and the water feed can be 50 cm to 2 m. The mixing section only needs to be long enough to allow the water to be sufficiently mixed with the relatively dry concrete mix and, ultimately, to allow the binder to be evenly absorbed.

[0028] The quality of the finished concrete mix depends largely on the water and binder supply. The supply can be regulated via valves. These valves for opening and closing the water, binder, and air supply are conveniently located directly on the lance. The lance operator can precisely control all three valve positions and readjust them during the concrete spraying process to achieve an optimal mix ratio.

[0029] In a further development of the invention, the valve for the water supply and the valve for the binding agent supply are arranged adjacent to each other at a distance of less than 30 cm, so that a lance operator only needs one hand to operate both valves while holding the lance with the other hand. The device according to the invention is designed for one-person operation. If the valves required for operation are close together, the concrete spraying can continue while the operator corrects the valve positions or selects them so that the correct mixing ratio can be set.

[0030] In a further development of the invention, it is additionally provided that the air supply valve is also arranged at a distance of 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 hand. This concept is also based on one-person operation of the device, and in particular the lance. For ergonomic reasons, all necessary settings for operating the lance or spraying device can be combined in such a way that the operator can always hold the lance with one hand and does not have to interrupt their work when operating the valves.

[0031] In a further advantageous development, the invention provides that the valve for the water supply, the valve for the binding agent supply, and the valve for the air supply can be operated via a single, common actuating lever. All three gas and liquid flows can be started and stopped via a common actuating lever, acting as a start-stop function. The respective valve positions can be adjusted independently of one another, preferably to achieve the desired mixing ratio. The respective valve position can be adjusted independently of the actuating lever.

[0032] For one-person operation of the device according to the invention, it is advantageous if the lance has a line cross-section of less than 50 mm, so that the lance can be carried and operated by a single person. The line cross-section of less than 50 mm preferably also extends into the area of ​​the delivery line. The lance preferably has a diameter of 40 mm to 45 mm.

[0033] The lance according to the invention is particularly designed and constructed to deliver refractory concrete, particularly to a hot tapping launder of a melting furnace. As mentioned above, the concrete used is, in particular, dry concrete, which can be transported by air within the conveying line. There is no upper limit on the grain size. In combination with a pneumatic rotor spraying machine, via which the concrete can be introduced into the conveying line, dry concrete with a grain size of up to 19 mm can be processed.

[0034] In an advantageous development of the invention, the rotor spraying machine comprises a remote control for start-stop with respect to the concrete to be conveyed and the conveying air for conveying the concrete, wherein the remote control is arranged in the region of the valves for the water supply, the binder supply and the air supply.

[0035] In a further development of the invention, the remote control and the valves can be actuated via a common actuating element.

[0036] The device according to the invention creates a possibility for spraying shotcrete with significantly fewer personnel and less equipment. Cleaning the device according to the invention also significantly reduces concrete loss compared to the prior art.

[0037] The invention is explained in more detail below with reference to exemplary embodiments, which are shown purely schematically in the drawings. They show: Figure 1 shows a device for spraying concrete and Figure 2 shows a nozzle ring for an alternative device for spraying concrete.

[0038] The Figure 1 shows a device 1 for sprinkling concrete with a delivery line 2 in the form of a flexible transport hose. The transport hose has a diameter of preferably less than 50 mm, in particular a diameter of 45 mm.

[0039] A dry concrete mix 3 is pneumatically introduced into an inlet end 5 of the conveying line 2 via a rotor spraying machine 4 and transported to its outlet end 6. Connected to the outlet end 6 is a water inlet 7, which is designed and configured to introduce water into a mixing section 8 extending in the direction of flow of the concrete mix 3. The water inlet 7 is annular, so that the water can be supplied to the concrete in a distributed manner around its circumference. Several inlet points for the water are symbolically shown in the area of ​​the water inlet 7. This is an annular arrangement surrounding the mixing section 8.

[0040] Downstream of the water inlet 7, there is an annular binder inlet, for example for supplying silicate or water glass. Here, too, several inlet openings are shown as examples so that the concrete mix previously mixed with water can be evenly wetted with the binders. The binder inlet 9 is followed by a further mixing section 10 and finally an annular air inlet 11. The air inlet 11 creates an annular air flow 12 between an outer casing of the lance 13 and a nozzle ring 14 that is adjustable in the longitudinal direction of the lance 13. The size of the concrete spray cone can be influenced depending on the position of the nozzle ring 14 relative to the lance 13 or relative to the strength of the air flow 12.

[0041] The Figure 1shows that valves 15, 16, 17 for the supply of water, binder and air are arranged relatively close to one another, in this case in the area of ​​the binder feed 9. The binder feed 9 is located approximately in the middle area between the upstream mixing section 8 and the downstream mixing section 10 in the direction of flow. The valves 15, 16, 17 are arranged so that they can be easily operated by a single person carrying the lance 13. The distance between the valves 15, 16, 17 is preferably less than 30 cm. The actuations of the valves 15, 16, 17 can be combined with one another, so that single-lever operation of all three material flows is possible. In addition, the air and material supply to the rotor spraying machine 4 can also be controlled via a remote control 18 for the rotor spraying machine 4.

[0042] The Figure 2shows an alternative embodiment of a lance 13, where for functionally identical components the Figure 1 The reference symbols used are retained.

[0043] The front end of the lance 13 is shown in longitudinal section. The lance 13 extends to its outlet end 22, at which the concrete mix 3 exits as a material stream M according to the central arrow. The air supply 11 is shown on the lance 13. The air supply 11 comprises a nozzle ring 14. This is a circular-cylindrical tube whose diameter is slightly larger than the lance 13 and defines an annular space 21 with the lance 13. The annular space 21 is a narrow gap with a width S1. In this case, the width S1 is 3 mm. The diameter D1 of the lance 13 is 40 mm. The annular space 21 is open towards the outlet end 22 of the concrete mix 3 of the lance 13. Its other axial end is closed. The annular space 21 is surrounded around its entire circumference by an air distribution chamber 19. An air line 24 for air supply is connected radially to the outside of the air distribution chamber 29.Openings 24 are arranged distributed over the inner circumference of the air distribution chamber 19. Through the openings 24, air flows from the air distribution chamber 19 evenly from all sides radially into the annular space 21. In the annular space 21, the air is deflected in the axial direction, so that a purely axially oriented air flow 12 is generated at the outlet end 22, which is guided parallel to the material flow M. The air flow 12 is not directed into the material flow M, i.e. there are no means on the nozzle ring 13 that cause the air flow to be at an acute angle to the material flow.

[0044] The air flow 12 is guided beyond the outlet end 12 by the nozzle ring 14, as the nozzle ring 14 extends beyond the outlet end 12. This cylindrical end portion 23 of the nozzle ring 14 has a length L1 that is greater than the diameter D1 of the lance 13. In this case, it is 70 mm.

[0045] The air flow 23 flows along the inner side 25 of the end section 23 parallel to the material flow M. The material flow M is completely surrounded by the parallel air flow 12. The air flow 12 is not directed into the material flow M. Reference symbols:

[0046] 1 - Device for spraying concrete 2 - Conveying line 3 - Concrete mix 4 - Rotor spraying machine 5 - Inlet end of 2 6 - Outlet end of 2 7 - Water supply 8 - Mixing section 9 - Binder supply 10 - Mixing section 11 - Air supply 12 - Air flow 13 - Lance 14 - Nozzle ring 15 - Valve for water supply 16 - Valve for binder supply 17 - Valve for air supply 18 - Remote control for rotor spraying machine 4 19 - Air distribution chamber 20 - Opening 21 - Annular space 22 - Outlet end of 13 23 - End section of 14 24 - Air line 25 - Inside of 14 D1 -Diameter of 13 L1 -Length of 23 M -Material flow of 3 S1 -Width of 21

Claims

1. An apparatus (1) for spraying concrete, with the following features: a) a conveying line (2) which is configured and designed to receive concrete from one inlet end (5) and to direct it to its other outlet end (6), b) a lance (13) which is configured and designed to deliver the concrete by spraying; c) the lance (13) has an inlet end for the concrete, which is 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) such that the concrete mixes with the water in the lance (13) and the flowability of the concrete within the lance (13) is increased; d) in the direction of flow of the concrete at a distance from the water supply (7), a binding agent supply (9) is connected to the lance (13), wherein the binding agent supply (9) is configured and designed to introduce a binding agent into the concrete enriched with water; e) at a distance from the binding agent supply (9), an air supply (11) is connected to the lance (13), which is configured and designed to form an annular air flow (12) which determines the size of a spray cone of the concrete emerging from the lance (13); f) at an outlet end (22) of the lance (13), a nozzle ring (14) is arranged which is configured and designed to form the annular air flow (12) surrounding the material flow (M) of the emerging 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), characterised in that in the annular space (21), the air is deflected in an axial direction such that at the outlet end (22), a purely axially oriented air flow (12) is generated, which is guided parallel to the material flow (M).

2. The apparatus according to claim 1, characterised in that the lance projects by a length (L1) relative to the outlet end (22).

3. The apparatus (1) according to claim 1 or 2, characterised 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 spray cone of the concrete.

4. The apparatus (1) according to claim 3, characterised in that the annular space (21) is connected to an air distribution chamber (19), which borders the annular space (21), by a plurality of openings (20) distributed over its circumference.

5. The apparatus (1) according to any one of claims 1 to 3, characterised in that valves (15, 16, 17) for opening and closing the water supply (7), the binding agent supply (9) and the air supply (11) are arranged on the lance (13).

6. The apparatus (1) according to claim 5, characterised in that the valve (15) for the water supply (7), the valve (16) for the binding agent supply (9) and the valve (17) for the air supply (11) can be actuated via a single common actuating lever.

7. The apparatus (1) according to any one of claims 1 to 6, characterised in that the lance (13) has a line cross-section of less than 50 mm such that the lance (13) can be carried and operated by a single person.

8. The apparatus (1) according to any one of claims 1 to 7, characterised in that the lance (13) is configured and designed to dispense refractory concrete.

9. The apparatus (1) according to any one of claims 1 to 8, characterised in that the concrete, transported via the conveying line (2), is dry concrete which can be transported with air within the conveying line (2).

10. The apparatus (1) according to any one of claims 1 to 9, characterised in that it is designed and configured to spray dry concrete with a grain size of up to 19 mm.

11. The apparatus (1) according to any one of claims 1 to 10, characterised in that the concrete can be introduced into the conveying line (2) by means of a pneumatic rotor spraying machine (4).

12. The apparatus (1) according to claim 11, characterised in that the rotor spraying machine (4) has a remote controller (18) for starting and stopping with respect to the concrete to be conveyed and conveying air, wherein the remote controller (18) is arranged in the region of the valves for the water supply (7), the binding agent supply (9) and the air supply (11).

13. The apparatus (1) according to claim 12, characterised in that the remote controller (18) and the valves (15, 16, 17) can be actuated via a common actuating element.