WO2024146855A1

WO2024146855A1 - Method and device for cleaning concrete mixers, and concrete mixing plants

Info

Publication number: WO2024146855A1
Application number: PCT/EP2023/087877
Authority: WO
Inventors: Markus Bürgin; Marc KEUSCH; Reto Urs STEINER
Original assignee: Bang & Clean Gmbh
Priority date: 2023-01-04
Filing date: 2023-12-28
Publication date: 2024-07-11

Abstract

The invention relates to a method for removing adhering deposits and incrustations made of hardened concrete in mixing drums (54) of concrete mixers (50, 51) for transporting flowable concrete. An exothermic chemical reaction is triggered by means of a device (1, 101), which chemical reaction generates a pressure wave in the interior (54) of the apparatus (50, 51), which causes the deposits and incrustations made of hardened concrete in the interior to flake off.

Description

METHOD AND DEVICE FOR CLEANING

TRUCK MIXERS AND CONCRETE MIXING PLANTS

The invention relates to a method and a device for removing adhering deposits and encrustations from hardened concrete in the interiors of facilities for the production, storage and/or transport of flowable concrete.

Truck mixers, also known as mobile concrete mixers, are trucks with a rotating drum in which the flowable fresh concrete is transported to the construction site. The fresh concrete is fed into the drum via an upper hopper. The drum rotates during the journey and prevents the flowable fresh concrete from setting prematurely.

Inside the rotating drum, the screw conveyor of a screw conveyor is arranged to transport the flowable fresh concrete out of the drum.

When the drum is unloaded, concrete residues stick to the inner walls of the drum and to the surface of the conveyor screw. If the drum is not cleaned thoroughly immediately after unloading, concrete residues adhering to the walls and the conveyor screw can harden over time. This leads to hard deposits and encrustations of hardened concrete inside the drum, which can practically only be removed using mechanical means.

Since these deposits can reach critical thicknesses that impair the functionality of the truck mixer, they must be removed again. It is well known that concrete deposits can be removed by hand using a hammer and chisel.

It is also known to clean the inside of the drum using water by means of a high-pressure cleaner.

However, conventional cleaning methods for removing deposits and encrustations from hardened concrete are cumbersome and time-consuming and therefore not very effective. Some methods are also only suitable if the concrete residues have not yet hardened.

The publication US2002036003 Al, for example, describes a washing device for washing out a concrete mixing drum of a truck mixer using a spray system. This cleaning system is particularly suitable when the concrete residues in the concrete mixing drum have not yet hardened.

Publication EP 3 556 481 A1 also describes a device for washing out a concrete mixing drum of a truck mixer. The cleaning liquid is introduced into the concrete mixing drum via a cleaning arm. The cleaning system is also particularly suitable when the concrete residues in the concrete mixing drum have not yet hardened.

The publication WO 2017/042802 describes a cleaning process in which the concrete mixing drum is partially filled with water and a gas pulse generator arranged under water generates shock waves which cause concrete residues to be removed from the surfaces.

It is an object of the present invention to propose a method and a device by means of which deposits of hardened concrete can be detached and removed from the interior of such drums in an efficient manner and with as little manual work as possible. The method and the device should also be suitable for removing deposits from hardened concrete in the interior of concrete mixing plants in general.

The cleaning process should also be simple and safe to use.

The process should also make it possible to remove deposits of hardened concrete from interior surfaces without the need for the presence of workers in the interior.

The process should also not produce any residues of cleaning agents, such as water, which would have to be disposed of separately or recycled.

The object is solved by the features of independent claims 1 and 18. Further developments and special embodiments of the invention emerge from the dependent claims, the description and the drawings.

The invention is characterized in that the device triggers an exothermic chemical reaction which releases a pressure wave in the interior of the device, which leads to the flaking off of the deposits and encrustations of hardened concrete in the interior.

The device for producing, storing and/or transporting flowable concrete is in particular a truck mixer in which the rotatable drum or mixing drum is cleaned by means of the method according to the invention and the associated device.

The facility for the production, storage and/or transport of flowable concrete can also be a concrete mixing plant, in which its mixing and/or Storage containers can be cleaned by means of the method according to the invention and the associated device.

The exothermic chemical reaction is in particular a combustion process. The combustion process is in particular an explosion. If the combustion process is associated with an explosion, the interior of the facility is cleaned using explosion technology.

The explosion can occur in the form of a deflagration. The explosion can occur in the form of a detonation.

The exothermic chemical reaction is triggered in particular by the ignition of a reactive, particularly flammable and particularly explosive substance.

The reactive substance may be an explosive, such as a blasting agent.

The reactive substance is in particular produced or mixed from at least two starting components.

The production or mixing of the reactive substance from the at least two starting components takes place in particular during a cleaning cycle.

The reactive substance is in particular a flammable and in particular explosive gaseous mixture. The flammable or explosive gaseous mixture is in particular produced or mixed from at least two starting components. The at least two starting components can be gaseous or liquid. The at least two starting components are in particular gaseous or change into the gaseous state during the production of the mixture. The starting components can be liquid, especially when they are under pressure in pressure vessels. The liquid starting components can, for example, only change into the gaseous state when the explosive, gaseous mixture is produced.

A first starting component is in particular a fuel. The fuel can in particular be a rapidly evaporating liquid. The fuel is in particular from the group of combustible hydrocarbons, such as acetylene, ethylene, methane, ethane or propane, petrol or diesel.

A second gaseous component is in particular an oxidizing agent, such as oxygen or an oxygen-containing gas.

The combustible or explosive gaseous mixture is formed in particular from a first starting component, which is a fuel, and a second starting component, which is an oxidizing agent.

The explosive, gaseous mixture is produced or mixed from the at least two starting components in particular during the process according to the invention, i.e. during each cleaning cycle.

By igniting the reactive substance, in particular the flammable or explosive gaseous mixture, an explosion is triggered, which creates a pressure wave or explosion pressure wave, which leads to the flaking off of deposits and encrustations of hardened concrete inside the device.

The exothermic chemical reaction is triggered in particular in the interior of the facility. According to this first variant, an explosion of a flammable or explosive reactive substance also occurs in particular in the interior of the facility The corresponding pressure wave is also generated on site in the interior of the facility.

If the reactive substance is a flammable or explosive gaseous mixture, it can be provided in a container shell or a container of a cleaning device of the device.

"Providing" means in particular that the container shell or the container is filled with an explosive, gaseous mixture. "Providing" can, however, also mean that the container shell or the container is filled with at least two starting components, whereby the explosive mixture is formed in the container shell or in the container.

In the latter case, the at least two starting components can be introduced into the container shell or into the container one after the other or simultaneously.

The at least two output components can be introduced into the container shell or into the container via a common feed or supply line, e.g. one after the other, or via separate feed or supply lines, e.g. simultaneously.

According to one embodiment, the cleaning device of the device comprises a particularly pressure-resistant container with a pressure chamber or explosion chamber, which has a pressure outlet opening that can be closed via a closure member.

To carry out the process, an explosive substance, in particular an explosive gaseous mixture, is provided in the pressure chamber of the container. The explosive substance is under pressure in the pressure chamber. The pressure can be, for example, several bar or several 100 kPa.

To generate a pressure wave, the explosive substance in the pressure chamber is ignited by an ignition device and caused to explode.

Before, during or after the ignition of the explosive substance, the outlet opening is opened by actuating the closure device, whereby an (explosive) pressure wave escapes through the outlet opening into the interior of the facility. The pressure wave causes hard concrete deposits to chip off the inner wall of the interior.

The outlet opening is released before or after the ignition of the explosive substance, in particular fractions of a second before or after the ignition of the explosive substance.

The starting components, in particular gaseous ones, are fed into the pressure chamber via a feed line from dosing containers. The dosing containers are in turn fed in particular from gas storage devices, such as gas bottles.

The closure member is in particular a closure piston. The device can be designed in such a way that the closure member or closure piston is actuated by the explosion of the explosive substance, thereby releasing the outlet opening. For this purpose, the closure member or closure piston can have a pressure application surface, via which an opening pressure or an opening force is exerted on the closure member or closure piston by the substance exploding in the pressure chamber.

It can also be provided that the opening pressure or the opening force is generated by a secondary explosion, which occurs, for example, in a secondary chamber. However, the closure element can also be actuated by an actuating mechanism. The actuation of the actuating mechanism is controlled in particular by a control device and is particularly synchronized with the ignition of the explosive substance. The actuating mechanism can also be actuated by the explosion of the explosive substance or by a secondary explosion itself.

The closure member can interact with return means which return the closure member to the closed position after the explosion pressure has escaped from the pressure chamber.

The return means can be, for example, a gas chamber filled with a gas in which a gas is compressed when the locking member moves back into the opening position. The locking member returns to the closed position when the gas is released after the explosion pressure escapes from the pressure chamber. The return means can therefore be designed as a gas pressure spring.

The return means may also comprise a (mechanical) return spring, such as a compression spring, which is pre-tensioned when the closure member is moved.

In order to carry out the method according to the invention, the cleaning device or its container can be mounted on the device to be cleaned with the outlet opening pointing into the interior.

The cleaning device or its container can also be attached to an insertion device, such as a lance, and can be inserted into the interior via this or can be positioned in an opening to the interior.

The container may contain an outlet channel, such as an outlet funnel, connected to the outlet opening. According to a further embodiment, the cleaning device of the device comprises a container casing. The container casing is in particular thin-walled. The container casing is in particular flexible and, for example, foldable. The container casing is in particular designed as a consumable which is destroyed when the explosive, gaseous mixture is ignited. The container casing can have a capacity of 50 to 300 liters, in particular 100 to 250 liters.

The container cover can be made of paper or plastic, for example. The container cover can also consist of a layered composite.

To carry out the method, the container shell, in particular an empty one, is introduced into the interior of the device and then filled with a combustible and in particular explosive gaseous mixture or at least two starting components thereof.

For this purpose, the container shell can be connected to a transport line. The flammable or explosive gaseous mixture or at least two of its initial components are transported to the container shell via the transport line.

According to a further embodiment, a cloud of combustible and in particular explosive gaseous mixture is generated in the interior of the device by means of the device or the cleaning device.

The flammable or explosive gaseous mixture or its at least two starting components can be transported by means of a transport line to an outlet device connected to the transport line and discharged into the interior of the device via at least one outlet opening of the outlet device, forming the cloud. The outlet device contains, in particular, a diffuser. The diffuser is characterized by a funnel-like expansion of the outlet opening. This causes a reduction in the outflow speed of the flammable or explosive gaseous mixture. This also reduces or prevents the turbulence of the flammable or explosive gaseous mixture as it exits the outlet device and thus the mixing of the flammable or explosive gaseous mixture with the surrounding atmosphere.

According to a second variant, the exothermic chemical reaction is triggered outside the interior of the device or takes place outside. Accordingly, an explosion also takes place in particular outside the interior of the device. According to this variant, the resulting pressure wave is directed into the interior of the device. This can be done, for example, via appropriate pressure wave introduction means. The pressure wave introduction means can, for example, comprise a pipe with an outlet opening directed into the interior of the device.

As already mentioned, the flammable and in particular explosive gaseous mixture or its starting components can be conveyed or transported to the interior of the facility or introduced into it in particular via at least one supply or transport line.

According to one variant, the flammable and in particular explosive gaseous mixture is produced or mixed from the at least two starting components, in particular outside the interior of the device, and conveyed or transported into the interior of the device via the at least one transport or supply line.

According to a particular embodiment of the method, which contains features as described above, it comprises the steps:

Providing a gaseous, explosive mixture in the at least one transport line; - Transporting the gaseous, explosive mixture to an outlet opening on the cleaning side of the transport line;

- controlled ignition of the gaseous, explosive mixture by means of an ignition device, whereby the gaseous, explosive mixture is caused to explode.

According to a first variant of this embodiment, the method comprises the following steps:

- Attaching a container cover to the outlet opening of the transport line on the cleaning side;

- Inserting the container shell into the interior of the facility;

- Filling the container shell with the gaseous, explosive mixture transported through the transport line.

According to a second variant of this embodiment, the method comprises the following steps:

- The explosive mixture flows out through at least one outlet opening of the transport line on the cleaning side into the interior of the device and forms a cloud of gaseous, explosive mixture.

The invention also relates to a device for carrying out the method described above.

The device is characterized by a cleaning device for generating or triggering an exothermic chemical reaction by activating the reactive substance and releasing a pressure wave in the interior of the device.

The device may further comprise a supply device for providing the reactive substance or its starting components. The cleaning device may contain an ignition device for igniting the reactive substance.

The ignition device is arranged in particular in the mixing zone of a mixing unit or downstream of the mixing zone. The ignition device is arranged in particular in the mixing unit or a transport line connected to it.

The device contains in particular a control device for controlling the ignition of the reactive substance by means of the ignition device.

The control device also serves in particular to control the dosed provision of the reactive substance.

If the reactive substance, such as a flammable or explosive gaseous mixture, is produced from at least two starting components, the device in particular contains a mixing unit for mixing the reactive substance from the at least two starting components.

The cleaning device can contain pressure introduction means for introducing the pressure wave triggered by the exothermic chemical reaction into the interior of the device. This applies in particular if the exothermic chemical reaction is triggered or takes place outside, e.g. completely or partially outside, the interior of the device to be cleaned. The means can comprise a pressure outlet device and/or a pressure wave line.

The cleaning device contains in particular at least one transport line for transporting the reactive substance or its starting components to the interior of the device. The at least one transport line serves in particular for introducing the reactive substance or its starting components into the interior of the device. The transport line is connected in particular to a mixing unit.

The transport line forms at least one closed transport channel through which a flammable or explosive gaseous mixture or its starting components can be transported.

The transport line can be designed as a transport pipe, in particular a rigid one, or can contain one. The transport line can be designed as a transport hose or can contain one. The transport line can have one or more closed transport channels.

The transport line can be made of metal such as steel or plastic.

The transport channel can have a (largest) diameter of 60 mm or less, 50 mm or less, 40 mm or less, 30 mm or less, or even 20 mm or less.

The (largest) diameter can be 5 mm or larger, 10 mm or larger, 20 mm or larger, or even 30 mm or larger.

If the reactive substance is a flammable and in particular explosive gaseous mixture, the supply device contains in particular at least one pressure vessel for storing the flammable or explosive gaseous mixture or its starting components.

If the flammable or explosive gaseous mixture is produced from at least two starting components, the supply device comprises at least two pressure vessels for storing the respective starting components. This means that a pressure vessel is provided for each starting component. The pressure vessels can be gas bottles, for example, as are commercially available. In a further development, the supply device contains at least one dosing container for the metered provision or production of a flammable or explosive gaseous mixture.

If the flammable or explosive gaseous mixture is produced from at least two starting components, the supply device according to the development contains at least two dosing containers for the respective starting components. This means that one dosing container is provided for each starting component.

The flammable or explosive gaseous mixture or its starting components intended for a cleaning cycle are stored or temporarily stored under pressure in the dosing containers.

The at least one dosing container is fed in particular from the at least one pressure vessel with a flammable or explosive gaseous mixture or with its starting components. Accordingly, the at least one dosing container is connected in particular to the at least one pressure vessel via at least one feed line.

The device contains at least one valve for the controlled release of flammable or explosive gaseous mixture or of its starting components from at least one dosing container or pressure vessel.

In particular, the device contains a corresponding valve for each dosing container or pressure vessel. The valve can be used to control the amount of flammable or explosive gaseous mixture or its starting components that is to be released from the associated dosing container or pressure vessel.

The fittings are controlled in particular via the control device. In particular, the fittings also have the function of inlet fittings for admitting the flammable or explosive gaseous mixture or its starting components into a mixing unit or a transport line.

The control of the valves by the control device serves in particular to provide or produce a flammable or explosive gaseous mixture in a metered manner. The valves are accordingly metering valves.

The dosage is used to provide the optimal amount of flammable or explosive gaseous mixture for a cleaning cycle. The optimal amount is characterized by the fact that a sufficiently strong pressure wave is generated so that the deposits of hardened concrete flake off the surfaces. However, the pressure wave should not be too strong so that no components are damaged.

For example, a metered amount of flammable or explosive gaseous mixture of 100 to 200 liters can be produced for a cleaning cycle.

If the flammable or explosive gaseous mixture is made from at least two starting components, the dosing serves in particular to provide the individual starting components in a stoichiometric ratio. The stoichiometric ratio reflects the ratio of starting components specified by the associated reaction equation.

Two methods are available to provide a specific quantity of flammable or explosive gaseous mixture, and in the case of several starting components, in particular in a stoichiometric ratio of starting components. According to a first method, the starting components are provided in the appropriate stoichiometric ratio in the dosing containers. When the dosing containers are completely emptied and the starting components provided from the dosing containers are mixed, a flammable or explosive gaseous mixture in a stoichiometric ratio is automatically created.

According to a second method, the quantities of starting components required for a stoichiometric ratio are provided by a so-called differential pressure process. According to this process, the starting components are discharged from the dosing containers between a maximum pressure at the beginning of the introduction and a target residual pressure after completion of the discharge process, with the target residual pressure being in an overpressure range.

The target residual pressure can be calculated in advance based on the maximum pressure at the beginning of the discharge process and the amount of output component to be introduced.

The target residual pressure is determined based on the amount of output components to be discharged, starting from the maximum pressure, and the discharge process is stopped when the target residual pressure is reached.

For this purpose, during the discharge process of the at least two output components, the pressure in the at least two dosing containers is measured by means of at least one pressure sensor.

The at least two dosing valves are controlled by the control device depending on the pressure values measured by the at least two pressure sensors in the dosing container. This means that as soon as the pressure sensors measure the target residual pressure, the discharge process is controlled by the control device stopped by closing the dosing valves via the control device.

In principle, the differential pressure method can also be applied directly to pressure vessels or gas cylinders.

The differential pressure method can also be used if an already explosive gaseous mixture is discharged from at least one dosing container.

In principle, the two methods mentioned above can also be used to release a defined amount of flammable or explosive gaseous mixture from a pressure or dosing container.

The flammable or explosive gaseous mixture or its starting components are stored in the dosing container, particularly under pressure.

The at least one dosing container is supplied in particular from the at least one pressure vessel with a flammable or explosive gaseous mixture or with its starting components.

Thus, for each cleaning cycle, the at least one dosing container is filled anew with flammable or explosive gaseous mixture or its starting components from the at least one pressure container.

The flammable or explosive gaseous mixture or its starting components are introduced from the dosing container or the pressure vessel in particular into the transport line, e.g. via at least one feed line.

If output components are provided by the dosing tanks or the pressure tanks, they are fed downstream via at least one feed line in particular, into a mixing unit arranged upstream of the transport line. The mixing unit can be integrated into the supply device. The mixing unit can also be part of the cleaning device. The mixing unit can also be arranged between the at least one dosing container and the transport line.

According to a particular embodiment, the cleaning device comprises a cleaning lance with a supply-side end section into which the at least two starting components or the flammable or explosive gaseous mixture can be supplied and a cleaning-side end section with an outlet opening for the flammable or explosive gaseous mixture.

The cleaning lance includes a transport line, for example, designed as a rigid transport pipe.

The cleaning lance can be designed as a guide tube or as a cleaning device with an integrated mixing unit.

The cleaning-side end section of the cleaning lance can be inserted into the interior of the device to be cleaned.

Furthermore, the mixing unit can be arranged in the feed-side end section downstream of the transport line. The mixing unit can also be arranged upstream separately from the cleaning lance.

The supply-side end section of the cleaning lance forms in particular a hand part for holding the cleaning lance.

The flammable or explosive gaseous mixture or its starting components are fed in particular via at least one feed line from at least one pressure vessel or dosing vessel at the feed-side end section into the Cleaning lance embedded. The at least one supply line can be a hose, for example.

The transport of the flammable or explosive gaseous mixture or its starting components takes place from the end section on the supply side to the outlet opening on the cleaning side.

"Supply side" means in particular facing the supply device or arranged near the supply device, "cleaning side" means in particular in the operating position facing the point to be cleaned (cleaning point) or arranged at the cleaning point.

The transport line can be cooled. For this purpose, a cooling fluid, such as liquid or gas or a mixture thereof, can circulate in an annular channel formed in the transport line.

A container cover for the flammable or explosive gaseous mixture can be attached to the cleaning-side end section or to its outlet opening.

Thanks to the method according to the invention and the associated device, adhesions and encrustations of hardened concrete in mixing drums of truck mixers can be detached and removed from them in a simple, efficient and cost-effective manner.

The method according to the invention also leaves no cleaning agent residues, such as cleaning fluid, which must also be disposed of or recycled along with the removed concrete residues. The subject matter of the invention is explained in more detail below using preferred embodiments, which are shown in the accompanying drawings. They show schematically:

Figure 1: a first embodiment of a device according to the invention;

Figure 2: a side view of a truck mixer to be cleaned;

Figure 3: a second embodiment of a device according to the invention from the feed side area;

Figure 4: the cleaning side area of the device according to Figure 3;

Figure 5: an outlet device for a device according to the invention for forming a cloud of explosive gaseous mixture;

Figure 6: a third embodiment of a device according to the invention,

Basically, identical parts in the figures are provided with identical reference symbols. To facilitate understanding of the invention, certain features are not shown in the figures. The described embodiments are examples of the subject matter of the invention and have no limiting effect.

Figure 1 shows a cleaning device 1 for carrying out the cleaning method according to the invention. The cleaning device 1 comprises a cleaning device (cleaning device) in the form of a coolable cleaning lance 2. The cleaning lance 2 contains an outer casing tube 8 and an inner gas intake tube 7 arranged within the outer casing tube 8, which, among other things, forms the gas intake channel or transport channel 11. The outer casing tube 8 encases the inner gas intake tube 7 and thereby forms an annular cooling channel 12. The lance cooling and with it the casing tube 8 and the cooling channel 12 are not, however, a mandatory feature.

The cleaning lance 2 has a cleaning-side end section 4 and a supply-side end section 5. At the cleaning-side end section 4, the supply channel 11 opens into a container connection element with outlet openings 31 for an explosive, gaseous mixture. Furthermore, a container casing 29 is attached to the container connection element at the cleaning-side end section 4. The container casing 29 can be filled with the explosive, gaseous mixture provided in the cleaning lance 2 via the supply channel 11 and the outlet openings 31.

The cleaning lance 2 contains an inner tube 6 arranged in the gas intake tube 7 at the supply-side end section 5. The inner tube 6 forms a first inlet channel 9. The inner tube 6 ends in the direction of the cleaning-side end section 4 in the gas intake tube 7 and forms an outlet opening for the first inlet channel 9.

A second, annular inlet channel 10 is formed between the outer gas intake pipe 7 and the inner pipe 6. The two inlet channels 9, 10 merge at the end of the inner pipe 6 in the direction of the cleaning-side end section 4 into the feed channel 11, which is formed by the outer gas intake pipe 7. In this transition, the gas flows of a first and second gaseous starting component meet. A mixing zone 32 is formed in the said transition. The mixing zone 32 is part of a mixing unit 39 in the feed-side end section 5 of the cleaning lance 2. In the mixing zone 32, the two gaseous starting components are mixed to form an explosive, gaseous mixture and are passed as a mixture through the transport line 11 in the direction of the container shell 29.

The cleaning lance 2 also contains an ignition device 13 with an ignition-effective component, which is arranged in the feed channel 11, viewed in the direction of the cleaning-side end, after the end of the inner tube 6. The ignition device 13 is connected to a control device 3 via a control line 15a.

The cleaning device 2 further contains a supply device 37 with a first pressure storage container 24 in the form of a first gas bottle for Feeding a first gaseous starting component into the cleaning lance 2. The first gas bottle 24 is connected to a first dosing container 21 via a first gas line 22. The first dosing container 21 is fed with the first gaseous component from the first gas bottle 24. A filling fitting 23, in particular in the form of a valve, is arranged between the first dosing container 21 and the first gas bottle 24, which allows a controlled feeding of the first gaseous component from the first gas bottle 24 into the first dosing container 21. A first pressure sensor 17 is provided on the first dosing container 21 to measure the pressure in the first dosing container 21.

A first feed line 20 leads from the first dosing container 21 to the first inlet channel 9 of the cleaning lance 2.

A first dosing valve 18, in particular in the form of a valve, is arranged between the first dosing container 21 and the first inlet channel 9, which allows a metered introduction of the first gaseous component from the first dosing container 21 into the first inlet channel 9. The first dosing valve 18 is attached to the outlet of the first dosing container 21. However, the first dosing valve 18 can also be arranged in the supply-side end section 5 of the cleaning lance 2.

Furthermore, a first non-return device 19, such as a check valve, is installed between the metering valve 18 and the first inlet channel 9 to prevent a backflow of explosive gaseous mixture into the feed line 20 caused by the explosion. However, the non-return device 19 is not mandatory.

The supply device 37 further contains a second pressure storage container 24' in the form of a second gas bottle for feeding a second gaseous component into the cleaning lance 2. The second gas bottle 24' is connected to a second dosing container 21' via a second gas line 22'. The second dosing container 21' is filled with the second gaseous component from the second gas bottle 24'. Output component is fed. Between the second dosing container 21' and the second gas bottle 24' there is a second filling fitting 23', in particular in the form of a valve, which allows a metered feeding of the second gaseous component from the second gas bottle 24' into the second dosing container 21'. To measure the pressure in the second dosing container 21', a second pressure sensor 17' is provided on the second dosing container 21'.

A second feed line 20' leads from the second dosing container 21' to the second, ring-shaped inlet channel 10 of the cleaning lance 2. Between the second dosing container 21' and the second inlet channel 10 there is a second dosing fitting 18', in particular in the form of a valve, which allows a metered introduction of the second gaseous component from the second dosing container 21' into the second inlet channel 10. The second dosing fitting 18' is attached to the outlet of the second dosing container 21'. However, the second dosing fitting 18' can also be arranged in the supply-side end section 5 of the cleaning lance 2.

Furthermore, a second non-return device 19', such as a check valve, is installed between the second metering valve 18' and the second inlet channel 10 to prevent a backflow of explosive gaseous mixture into the second feed line 20' caused by the explosion. However, the non-return device 19' is not mandatory.

The first gaseous component is a combustible gas, such as acetylene, ethylene or ethane. The second gaseous component is oxygen or an oxygen-containing gas, which is supplied in larger quantities through the larger, second inlet channel 10 due to the stoichiometry.

The dosing containers 21, 21' are filled by opening the filling valves 23, 23', whereby the gaseous component flows from the gas bottle 24, 24' into the pressure vessel 21, 21'. The gaseous component can have a maximum pressure of between 20 and 40 bar in the pressure vessel 21, 21'. The Pressure vessels 21, 21' serve to dose the starting components, as described in more detail below.

The introduction of the gaseous components from the pressure vessel 21, 21' into the associated inlet channel 9, 10 is carried out by opening the metering valves 18, 18', whereby the gaseous component flows from the pressure vessel 21, 21' into the associated inlet channel 9, 10.

The dosing containers 21, 21' with the associated pressure sensors 17, 17' form in particular a dosing unit 38.

The dosing valves 18, 18' are controlled, i.e. opened or closed, by the control device 3 via control lines 15b, 15c.

The control device 3 comprises an input module 14 for entering control-relevant parameters, as already explained above.

The gaseous starting components are introduced into the cleaning lance 2 from the pressure vessels 21, 21' in defined quantities and in a stoichiometric ratio to one another. In this way, a defined quantity or volume of explosive gaseous mixture is produced in the correct stoichiometric ratio. Only the correct stoichiometric ratio of the gaseous starting components makes the gaseous mixture truly explosive.

Based on the desired amount of explosive gaseous mixture and the known stoichiometric ratio of the gas components, the exact amounts of the gaseous components can be calculated. Since the amount of gaseous component that is released from the pressure vessel can be calculated from the differential pressure in the pressure vessel, a target residual pressure can now be determined based on a maximum pressure at the beginning of the gas introduction. at which the predefined amount of gas has been released from the pressure vessel,

A value for the target residual pressure is stored in the control device 3. The pressure sensors 17, 17' are connected to the control device 3 via corresponding data lines 16a, 16b. The control device 3 then repeatedly measures the pressure in the pressure vessel 21, 21' using the pressure sensors 17, 17' on the pressure vessel 21, 21' while the gas is flowing out of the pressure surface 21, 21'. As soon as the measured pressure corresponds to the target residual pressure, the dosing valves 18, 18' are closed via the control device 3 and the introduction of gas into the cleaning lance 2 is stopped. Since the pressure vessel 21, 21' has a target residual pressure which is above the ambient pressure, the pressure vessel 21, 21' still contains a certain amount of gaseous component.

As an alternative to the aforementioned differential pressure method, the dosing containers 21, 21' can also be filled with the exact defined amount of starting component. Accordingly, the dosing containers 21, 21' - in contrast to the differential pressure method described above - are completely emptied when the starting components are introduced into the cleaning lance 2.

After the initial components have been introduced into the cleaning lance 2 and the explosive gaseous mixture has been produced in the mixing unit 39 of the cleaning lance 2, and after the container casing 29 has been filled with the explosive gaseous mixture, the explosive gaseous mixture is ignited via the control device 3 using the ignition device 13. The explosive gaseous mixture is ignited in the feed or transport channel 11, whereby the explosion propagates into the container casing 29 and causes it to explode. A viscous coolant 30 is introduced into the annular cooling channel 12 formed by the outer casing tube 8 and the inner gas intake tube 7 and is directed in the direction of the cleaning-side end section 4. The coolant 30 cools the gas intake tube 7 and thus the cleaning lance 2.

The cleaning lance 2 has connections for the feed lines 27, 28 of the coolant supply on its feed-side end section 5 or in its vicinity. Water, for example, is supplied through the first feed line 27 and air, for example, is supplied through the second feed line 28. It is also possible to provide only one coolant supply line for supplying only one coolant, e.g. water.

The coolant, e.g. a water/air mixture, is guided through the coolant channel 12 in a closed coolant circuit. Accordingly, connections for discharging the coolant can also be provided on the cleaning lance 2 (not shown).

The introduction of the coolant components into the coolant channel 12 is controlled by corresponding fittings 25, 26, such as valves. Operating the same allows the cooling to be switched on and off. This active lance cooling, or the valves 25, 26, can be operated manually or controlled via the control device 3. Accordingly, the fittings 25, 26 are connected to the control device 3 via control lines (not shown).

The coolant channel 12 can also be designed only for passive cooling and have an insulating effect and in this way protect the cleaning lance 2 and the explosive gas mixture or its components located therein from heating.

As already mentioned, the lance cooling described above is optional and not a mandatory feature of the present invention. To carry out the cleaning method according to the invention, the cleaning-side end section 4 of the cleaning lance 2 with the (empty) container casing 29 attached thereto is introduced in the insertion direction E through an inlet opening 53 into the interior 54 of a mixing drum 51 of a truck mixer 50. The feed-side end section 5 with the mixing unit 39, which forms a hand part, is not necessarily introduced into the mixing drum 51.

By operating the metering valves 18, 18', a predefined quantity of starting components, as described above, is introduced from the pressure vessels 21, 21' into the cleaning lances 2 and mixed in the mixing zone 32 to form an explosive, gaseous mixture. The starting components are introduced in a relatively short time. Depending on the level of the selected maximum pressure and the quantity to be introduced, the introduction can take from less than a second to a few seconds.

The explosive gaseous mixture produced in the mixing unit 39 flows in the flow direction S through the cleaning lance 2 to the cleaning-side end section 4 and through the outlet openings 31 into the container shell 29.

After the metering valves 18, 18' are closed, the explosive gaseous mixture is ignited and caused to explode immediately or with a time delay via the control device 3 by means of the ignition device 13.

The explosion creates a pressure wave which dislodges the deposits and encrustations of hardened concrete on the surfaces inside the concrete mixing drum 51.

The pressure wave generates vibrations or oscillations in the components of the mixing drum, which leads to the hard concrete residues breaking up and thus to their detachment. The explosion destroys or burns the container shell, which is designed as a consumable.

To start a new cleaning cycle, the cleaning-side end section 4 of the cleaning lance 2 is pulled out of the concrete mixing drum 51 again and fitted with a new container casing 29. A new cleaning process can begin. Depending on the degree of contamination, several cleaning cycles may have to be carried out inside a dirty concrete mixing drum 51 to completely remove the deposits and encrustations with hardened concrete. To do this, the container casing 29 can be positioned at a different point in the concrete mixing drum 51 for each cleaning cycle in order to increase the cleaning effect in selected areas.

Figure 2 shows a known truck mixer 50 with a concrete mixing drum 51 to be cleaned.

Figure 3 shows the cleaning device 101 according to the invention from the area of the supply device 137. The supply device 137 comprises a dosing unit 121 with dosing containers 122, 123 for supplying a mixing unit 112 connected downstream to the dosing unit 121 with a first and second starting component for producing the explosive, gaseous mixture. The first and second starting components are fed to the mixing unit 112 via supply lines 117, 118. The dosing containers 122, 123 are in turn supplied with the respective starting components via supply lines 127, 128 from gas bottles 125, 126, which in the present example are not integrated in the dosing unit 121.

The dosing unit 121 is designed as a mobile device on wheels, which is intended to simplify the handling of the cleaning device 101. The dosing unit 121 is also supplied with water and compressed air from the outside via corresponding supply lines 129, 130. These components are required to produce the cooling medium.

Furthermore, the dosing unit 121 also has a connecting line 136 to an external power source for power supply.

The dosing unit 121 also contains a control device 124 for controlling the cleaning process. The control device 124 controls, among other things, the introduction of the starting components into the mixing unit 112.

A mixing unit 112 is connected downstream to the dosing unit 121. A first component in the form of a gaseous fuel, such as ethylene, is introduced into a first feed channel 114 of the mixing unit 112 via a first supply line 117.

A second component in the form of a gaseous oxidizing agent, such as oxygen, is introduced into a second feed channel 115 of the mixing unit 112 via a second supply line 118. The two feed channels 114, 115 open into a mixing zone 113 of the mixing unit 112, in which the two components are mixed to form an explosive, gaseous mixture. The feed of the starting components into the mixing zone 113 of the mixing unit 112 can be carried out analogously to the embodiment according to Figure 1. The arrangement of fittings and pressure sensors can also be analogous to the embodiment according to Figure 1.

A transport hose 110 is connected downstream to the mixing unit 112 and is connected to the mixing unit 112 via a swivel joint 111. The explosive mixture is introduced from the mixing zone 113 via a transport channel into the transport channel 103 of the adjoining transport hose 110. In the present embodiment, the second supply channel 115 is arranged in a ring shape around the first supply channel 114. However, this arrangement is not mandatory.

The mixing unit 112 further contains an ignition device 131 with an ignition-effective component arranged in the mixing zone 113 or adjacent to the mixing zone. The ignition device 131 is connected to the dosing unit 121 or to the associated control device 124 via a connecting line 132. The ignition device 131 or the ignition process is controlled via the control device 124.

The mixing unit 112 further comprises a cooling channel 116, which is arranged in a ring shape around the mixing zone 113 or around the adjoining transport channel of the mixing unit 112.

The cooling medium 109 consists of water and air, which are each fed via separate supply lines 119, 120 from the dosing unit 121 into the cooling channel 116. The supply of the cooling medium 109 is also controlled via the control device 124.

The cooling medium 109 can also be guided through an (annular) cooling channel of the transport hose 110.

Even if the mixing unit 112 has a cooling device, transport hoses can also be connected which do not contain a cooling channel for introducing a cooling medium 109.

However, cooling and the associated equipment are not mandatory in this embodiment and can be omitted in some cases.

A check valve 133 is arranged on each of the two supply channels 114, 115, which prevents the introduction of pressure surges upstream from the Mixing unit 112 into the supply lines 117, 118 of the output components.

Figure 4 shows the cleaning device 101 according to the invention according to Figure 3 from the cleaning side area. The cleaning device 101 contains, as already mentioned, a transport hose 110, which is connected on the supply side to a mixing unit 112 (see Figure 3).

A guide tube 42, which is designed as a handpiece, is connected to the cleaning-side end of the transport hose 110. The guide tube 42 is connected to the transport hose 110 via a hose coupling 44.

The guide tube 42 has a transport channel through which the explosive gaseous mixture is introduced in the flow direction S from the transport hose 110 into the container casing 108. At the cleaning-side end, the guide tube 42 has a container connection element 43 with an outlet opening to which a container casing 108 is attached.

To clean the interior of the device or the mixing drum, the guide pipe 42 with the container casing 108, but not necessarily the transport hose 110, is introduced into the interior of the concrete mixing drum 51. However, the container casing 108 is only filled with the explosive, gaseous mixture in the interior, which is fed in the flow direction S through the transport channel 103.

As an alternative to a connecting element for a container shell, the cleaning device can also contain an outlet device 91 in the cleaning-side end section for generating a cloud 96 inside the concrete mixing drum 54 from an explosive, gaseous mixture, as shown in Figure 5. The outlet device 91 is connected to a feed pressure line 92 (transport line) with a Feed pressure channel 98, in which the explosive gaseous mixture is transported in the flow direction S to the outlet device 91.

The feed pressure line 92 can be a cleaning lance 2 according to Figure 1, a guide pipe 42 or a transport hose 1 according to Figure 4. The outlet device 91 contains a diffuser 93 with an outlet opening 95. The explosive gaseous mixture flows out via the diffuser 93 through the outlet opening 95 and forms the cloud 96. The diffuser 93 serves to reduce the exit speed of the explosive gaseous mixture. This is intended to prevent turbulence of the explosive gaseous mixture with the ambient atmosphere and thus dilution of the explosive gaseous mixture.

The outlet device according to Figure 5 and the operation thereof can alternatively be designed in such a way that only a receiving space of the diffuser 93 is filled with an explosive mixture and caused to explode. In this case, no cloud is generated outside the diffuser 93.

When the explosive gaseous mixture is ignited, an explosion pressure wave 97 spreads from the outlet opening 95 or from the cloud 96 into the interior 54 of the concrete mixing drum 51.

The device 71 according to Figure 6 comprises a pressure-resistant container 72 which forms a pressure chamber or explosion chamber 73. The pressure chamber 73 has an outlet opening 75 which can be closed via a closure piston 74.

To carry out the method according to the invention, a combustible gas, such as methane or propane, is fed into the reactor via a first feed or supply line 78 from a first dosing container 79, and an oxygen-containing gas, such as oxygen or air, is fed into the reactor via a second feed or supply line 80 from a second dosing container 81. introduced into the pressure chamber 73 closed by the closure piston 74. The introduction of the output components is controlled by a control device 84, which switches dosing fittings or valves 85, which are arranged on the feed or supply lines 78, 80.

The combustible gas and oxygen are introduced into the pressure chamber 73 and mixed in particular in a stoichiometric ratio.

The explosive gas mixture provided in the pressure chamber 73 in the aforementioned manner is caused to explode via an ignition device 82. The ignition device 82 is also controlled via the control device 84.

The closure piston 74 contains a pressurization surface 83 on which the explosion pressure acts. The force acting on the pressurization surface 83 due to the explosion pressure causes a displacement or retreat of the closure piston 74 from the closed position in which the outlet opening 75 is closed, into an open position in which the outlet opening 75 is open and the pressure wave 87 can escape through the outlet opening 75.

The pressure wave 87 escaping from the outlet opening 75 generates vibrations in the interior 54 of the device 50, 51, which leads to spalling of hardened concrete deposits in the interior 54.

The closure piston 74 interacts with return means 77, which return the closure piston 74 to the closed position after the explosion pressure has escaped from the pressure chamber 73. The return means 77 can be, for example, a gas chamber filled with a gas, such as nitrogen, in which a gas is compressed when the closure piston 74 returns to the opening position and is released again when the closure piston 74 returns to the closed position. The outlet opening 75 is connected to an outlet funnel 76, which in particular ensures a directed escape of the pressure wave 87.

Claims

PATENT CLAIMS

1. Method for removing adhering deposits and encrustations of hardened concrete in interior spaces (54) of facilities (50,51) for producing, storing and/or transporting flowable concrete by means of a device (1, 101), characterized in that an exothermic chemical reaction is triggered by means of the device (1, 101), which releases a pressure wave in the interior space (54) of the facility (50,51), which leads to the deposits and encrustations of hardened concrete in the interior space (54) flaking off.

2. Method according to claim 1, characterized in that the device (50, 51) for producing, storing and/or transporting flowable concrete is a truck mixer (50) or a concrete mixing plant,

3. Method according to one of claims 1 to 2, characterized in that the exothermic chemical reaction takes place in the form of a combustion process, in particular an explosion.

4. Method according to one of claims 1 to 3, characterized in that the exothermic chemical reaction is triggered by ignition of a reactive, in particular flammable and particularly explosive substance.

5. Method according to claim 4, characterized in that the reactive substance is a gaseous mixture or explosive.

6. Process according to one of claims 1 to 5, characterized in that the reactive substance is prepared by mixing at least two starting components.

7. Process according to one of claims 1 to 6, characterized in that a combustible and in particular explosive gaseous mixture is produced from at least two starting components.

8. Method according to one of claims 1 to 7, characterized in that the exothermic chemical reaction is triggered in the interior (54) of the device (50, 51).

9. Method according to one of claims 1 to 8, characterized in that the combustible and in particular explosive gaseous mixture is provided in a container shell (29, 108), wherein the container shell (29, 108) is destroyed upon ignition of the combustible or explosive gaseous mixture.

10. Method according to claim 9, characterized in that the container shell (29, 108) is introduced into the interior (54) of the device (50, 51) and is filled with a combustible and in particular explosive gaseous mixture.

11. Method according to one of claims 1 to 8, characterized in that a cloud (96) of combustible and in particular explosive gaseous mixture is generated by means of the device (1, 101) in the interior (54) of the device (50, 51).

12. Method according to one of claims 1 to 7, characterized in that the exothermic chemical reaction is triggered outside the interior (54) of the device (50, 51) and the pressure wave is guided into the interior (54) of the device (50, 51).

13. Process according to one of claims 1 to 12, characterized in that the reactive substance or its starting components are introduced via at least one Transport line (7 110) to the interior (54) of the device (50, 51).

14. Method according to one of claims 1 to 13, characterized in that outside the interior (54) of the device (50, 51) a combustible and in particular explosive gaseous mixture of at least two starting components is produced and transported via at least one transport line (7, 110) to the interior (54) of the device (50, 51).

15. Method according to one of claims 1 to 14, characterized by the steps:

- providing a combustible and in particular explosive gaseous mixture in the at least one transport line (7, 110), and

- transporting the flammable, in particular explosive, gaseous mixture to a cleaning-side outlet opening (31, 95) of the transport line (7, 110);

- controlled ignition of the combustible, in particular explosive, gaseous mixture by means of an ignition device (13, 131), whereby in particular an explosion is generated.

16. Method according to claim 15, characterized by the following steps:

- Attaching a container cover (29, 108) to the cleaning-side outlet opening (31, 95) of the transport line (7, 110);

- Filling the container shell (29, 108) with the flammable, in particular explosive, gaseous mixture emerging through the cleaning-side outlet opening (31, 95) of the transport line (7, 110).

17. Method according to claim 15, characterized by the following steps:

- outflow of the flammable and in particular explosive gaseous mixture through at least one cleaning-side outlet opening (31, 95) of the transport line (7, 110) into the interior (54) of the device (50, 51) and Forming a cloud (96) of combustible and in particular explosive gaseous mixture,

18. Method according to one of claims 1 to 13, characterized in that the device (71) comprises a pressure-resistant container (72) with a pressure chamber (73) which has an outlet opening (75) which can be closed by a closure member (74), comprising the steps:

- Providing an explosive substance, in particular an explosive gaseous mixture, in the pressure chamber (73) of the container (72);

- igniting the explosive substance by means of an ignition device (82);

- releasing the outlet opening (75) before, with or after ignition of the explosive substance by actuating the closure device (74), and

- Releasing a pressure wave through the outlet opening (75) into the interior (54) of the device (50,51).

19. Device for carrying out the method according to one of claims 1 to 18, characterized by a cleaning device for generating an exothermic chemical reaction by activating the reactive substance and for releasing a pressure wave in the interior (54) of the device (50, 51).

20. Device according to claim 19, characterized by a supply device (37, 137) for providing a reactive substance or starting components for producing a reactive substance.

21. Device according to one of claims 19 to 20, characterized in that the cleaning device contains an ignition device (13, 131) for igniting the reactive substance.

22. Device according to one of claims 19 to 21, characterized by a control device (3, 124) for controlling the ignition of the reactive substance by means of the ignition device (13, 131) and in particular for controlling the provision of the reactive substance.

23. Device according to one of claims 19 to 22, characterized by a mixing unit (5, 112) for mixing a reactive substance from at least two starting components.

24. Device according to one of claims 19 to 23, characterized in that the cleaning device contains pressure introduction means for introducing the pressure wave triggered by the exothermic chemical reaction into the interior (54) of the device (50, 51).

25. Device according to one of claims 19 to 24, characterized in that the cleaning device contains at least one transport line (7, HO) for transporting reactive substance, in particular combustible and in particular explosive gaseous mixture, or its starting components to the interior (54) of the device (50, 51).

26. Device according to one of claims 19 to 25, characterized in that the supply device (37, 137) is designed to provide a combustible and in particular explosive gaseous mixture or the at least two starting components, and contains at least one pressure vessel (24, 24'; 125, 126) for storing the combustible and in particular explosive gaseous mixture or the at least two starting components,

27. Device according to one of claims 19 to 26, characterized in that the supply device (37, 137) contains at least one dosing container (21, 21'; 122, 123) for dosing the combustible and in particular explosive gaseous mixture or the at least two starting components.

28. Device according to one of claims 19 to 27, characterized by at least one metering valve (18, 18') for the metered provision of the combustible, in particular explosive, gaseous mixture or its at least two starting components.

29. Device according to one of claims 19 to 28, characterized in that the at least one transport line (7, 110) comprises at least one transport hose (110) or one transport pipe (7).

30. Device according to one of claims 19 to 29, characterized in that the cleaning device (1) contains a cleaning lance (2) with a supply-side end section (5) into which the at least two starting components or the combustible and in particular explosive gaseous mixture can be fed and a cleaning-side end section (4) with an outlet opening (31) for discharging the combustible and in particular explosive gaseous mixture and/or a pressure wave.

31. Device according to one of claims 19 to 30, characterized in that the cleaning device (71) comprises a container (72) with a pressure chamber (73) which has a pressure outlet opening (75) which can be closed via a closure member (74).