DE102021134458A1 - Device for cleaning a surface around which a fluid flows - Google Patents

Abstract

The invention relates to a device (100) for cleaning a surface of a body around which a fluid flows, in particular a ship's hull (S) around which water (W) flows, comprising a first ultrasound transmitter (1) for coupling ultrasound into the body. According to the invention, the device (100) has means for autonomous operation of the first ultrasonic generator (1) and includes a holding system (2) for stationary attachment of the device (100) to the surface to be cleaned.

Description

The invention relates to a device for cleaning a surface of a body around which a fluid flows, in particular a ship's hull around which water flows, comprising a first ultrasound transmitter for coupling ultrasound into the body. The invention further relates to an associated method for cleaning.

STATE OF THE ART

Technical surfaces of bodies around which fluid flows, in particular ship hulls or, for example, inner walls of pipelines, are subject to permanent contamination and wear processes during operational use in the interaction with the fluid and/or substances or organisms entrained therein.

In the case of ship hulls, the growth on the surface below the waterline is a major problem. This process of unwanted settlement of organisms and organism communities, also known as fouling, leads to the formation of macroscopic layers of growth within a short time, which increase the flow resistance of the ship hull and in extreme cases cause a non-negligible increase in the weight of ships, which leads to a significant increase in ships' fuel requirements.

The use of biocide-containing coatings on the surface of ship hulls to prevent growth is only possible to a very limited extent due to legal requirements. Therefore, regular mechanical cleaning of the ship's hulls is carried out in shipping practice. For this purpose, the ships are brought into dry docks, for example, which is a disadvantageously time-consuming and cost-intensive procedure. Alternatively, cleaning work can be carried out in the harbor basin, for example manually by professional divers or by means of cleaning devices or robots, which are typically operated as wired systems from the deck of the ship in question. Such cleaning measures also require ships to stand idle for an undesirably long time, and there are also ordinances in force in numerous regions of the world which prohibit the cleaning of ships' hulls in the harbor basin in order to prevent invasive species from being introduced into the local ecosystem.

It is therefore desirable to carry out the cleaning of ships' hulls while the ship is underway, preferably at sea. In particular, an essentially continuous implementation of the cleaning can permanently prevent the formation of macroscopic fouling. A continuous cleaning operation is also desirable because, typically, after only a few days of undisturbed growth, significant aerodynamically disadvantageous effects become apparent, with cargo or cruise ships traveling for several weeks being not uncommon.

A method for cleaning ship hulls based on ultrasonic vibrations is known in the prior art. In this case, one or more ultrasonic transmitters are arranged on the inner surface of the ship's hull, which is accessible from inside the ship, in such a way that ultrasound can be coupled directly into the ship's hull by means of the transmitters. The ultrasonic propagation within the ship's hull causes vibrations of the outer surface to be cleaned and due to these vibrations the colonization of microorganisms on the outer surface is suppressed. The ultrasonic cleaning thus has an effect in particular on the early phase of the fouling process and is therefore preferably carried out in a continuous operating mode, so that the build-up of macroscopic growth layers is suppressed.

The main disadvantage of this method is the limited accessibility of the ship's hull from the inside of the ship, especially in the case of large ferries or cargo ships. A prerequisite for an effective ultrasonic excitation of the ship's hull is an appropriate placement of the ultrasonic transducer. It must be taken into account here that ship hulls are typically designed as surface structures, which are constructed from planar sheet metal elements capable of vibrating and frames, frames, beams or the like that support them. For an effective vibration excitation by means of coupled ultrasound, the respective ultrasonic generator should be arranged as centrally as possible on a sheet metal element, while an arrangement in the immediate vicinity of a carrier element does not lead to the desired vibration excitation and cleaning effect. Because of the limitations with regard to the positionability of the ultrasonic transducers, the cleaning method described is essentially only used on small ships, for example sports boats or yachts, but not on large cargo ships or ferries. Furthermore, the method cannot be used with double-walled ship hulls in which ultrasound coupling into the inner wall does not lead to significant vibration of the outer surface of the outer wall and therefore no cleaning effect can be achieved.

DISCLOSURE OF THE INVENTION

It is the object of the present invention to provide an alternative embodiment of a prior propose a device with at least one first ultrasonic transducer for cleaning a surface of a body around which fluid flows, in particular a ship's hull around which water flows, and a cleaning method based thereon.

This object is solved by a device according to claim 1 and a method according to claim 10. Advantageous developments of the invention are specified in the dependent claims.

The invention includes the technical teaching that the device has means for autonomous operation of the first ultrasonic generator and includes a holding system for stationary attachment of the device on the surface to be cleaned.

The basic idea of the invention is to enable the device to operate directly on the surface to be cleaned, i.e. within the fluid flow. For this purpose, the device is equipped with a holding system which allows the device to be conveniently arranged in any desired area on the surface to be cleaned. Due to this flexible positionability, the areas of the surface that are most suitable for effective ultrasound coupling into the body and/or the areas of the surface that are particularly in need of cleaning can be equipped with one or more devices according to the invention in a targeted manner. The means for self-sufficient operation integrated into the device enable at least temporary continuous operation of the device without the need for an external power supply or data connection.

When the device according to the invention is used for cleaning a ship's hull, the first ultrasonic generator is used to couple ultrasound, for example in the frequency range from 20 kHz to 100 kHz, into the ship's hull from the outside, i.e. the device is stationarily arranged on the ship's hull below the waterline and the first The ultrasonic transducer is preferably in direct body contact with the ship's hull. The hull, also referred to as the hull or hull, includes the entire underwater hull, i.e. the hull and the bottom of the ship, whereby the surfaces to be cleaned can also extend to sea chests, rudders, water coolers or propeller shafts, for example.

The power coupled into the ship's hull for cleaning is preferably designed in such a way that an antifouling effect with subcavitative intensity results. The ultrasound causes vibrations in the surface to be cleaned, which, even at low intensity, stimulate the surrounding water to such an extent that it is significantly more difficult for aquatic microorganisms and microorganisms such as barnacles to settle on the ship's hull. The disruption of this first stage of the "biofilm" that forms on the ship's hull effectively prevents the entire sequence of further colonization. In the context of the present invention, the term “cleaning” thus in particular also includes the aspect of preventive keeping of the treated surface clean.

In an advantageous embodiment, the means for self-sufficient operation include a turbine for extracting flow energy from the fluid flowing around, an electric generator and an accumulator, the electric generator being drivable by the turbine and being set up to charge the accumulator. In this embodiment, the device is largely self-sufficient in terms of energy, provided the surrounding fluid has a sufficient flow rate. In particular, when using the device on a ship's hull below the waterline, continuous cleaning operation can be carried out while the ship is underway. The turbine can, for example, be arranged at the end of the device, and the blade wheel of the turbine is preferably designed to be pivotable between a working position and a rest position. In the working position, the impeller offers the circulating fluid a high flow resistance and is set in rotation, and in the rest position the flow resistance is significantly reduced and the electric generator is not driven. The diameter of the impeller can be, for example, 20 cm to 30 cm, which means that with a flow speed of the fluid of 20 km/h and an overall efficiency (turbine and generator) of 50%, an electrical output of approx. 1 kW can be generated.

The holding system is preferably designed as a magnetic holding system for the detachable attachment of the device. The magnetic holding system includes in particular one or more permanent magnets for contact with the surface of the body to be cleaned. For example, rare earth magnets such as neodymium-iron-boron can be used for this purpose, which are particularly suitable for securely fastening the device according to the invention to a surface surrounded by a flow due to their high specific adhesive force.

The device preferably comprises a medium-tight housing, the housing in particular having a torpedo-like shape, ie the housing having an essentially circular cross-section, the diameter of the housing being able to vary along a direction of longitudinal extent. In this torpedo-shaped form, the housing, and thus the Vorrich tion, advantageously a very low flow resistance.

In an advantageous embodiment, the device according to the invention has a second ultrasound generator, which is set up to emit ultrasound into the surrounding fluid. No direct coupling of ultrasound into the body is provided by means of the second ultrasound generator; instead, the essential direction of emission of the ultrasound emitted by the second ultrasound generator is oriented parallel to the surface to be cleaned. The resulting cleaning effect is based on the formation of cavitation bubbles within a boundary layer of the fluid on the surface to be cleaned, and the energy released when the cavitation bubbles implode in the form of pressure surges causes impurities adhering to the surface to flake off. Furthermore, harmful microorganisms near the surface are rendered harmless by the direct impact of the ultrasound and the cavitation effect. In order to achieve a range that is sufficient in practice, the second ultrasonic generator preferably has a power of the order of 100 W to 1 kW.

The first ultrasonic generator can be operated in particular in a power range from 10 W to 100 W, since it has been shown that an expedient ultrasonic vibration excitation of ship hull segments is generated with such powers. The direct coupling of ultrasound into the body can be generated in particular by a robust solid-state contact between the first ultrasonic transducer and the body, whereby this solid-state contact can also be formed indirectly, for example by the contact being mediated by a permanent magnet of the magnetic holding system.

With a further advantage, the device has a pull-off device, by means of which the device can be detached from the surface to be cleaned against the holding force of the holding system. For example, the pull-off device can be designed in such a way that the device can be pushed off the surface of the body by actuating an extendable spindle.

The device also has a microphone, for example, which is set up to record ultrasound from the body. When using a plurality of devices according to the invention on a surface to be cleaned, for example, the frequency of the ultrasonic vibration coupled into the body by another device can be determined on the basis of the microphone recording.

In particular, the device has a control unit for controlling the electrically operated components. The control unit serves as a signal transmitter for the ultrasonic transmitters, it being possible for the first and second ultrasonic transmitters to be controlled by different control signals.

The invention also relates to a method for cleaning a surface of a body around which a fluid flows, in particular a ship's hull around which water flows, the cleaning being carried out by means of at least one device according to one of the previous embodiments, the device being stationary by means of the holding system on the to cleaning surface is attached, and ultrasound is coupled into the body by means of the first ultrasound generator and/or ultrasound is emitted into the surrounding fluid by means of the second ultrasound generator.

• - eine erste Vorrichtung Ultraschall mit einer Sollfrequenz einkoppelt,
• - die übrigen Vorrichtungen den eingekoppelten Ultraschall mittels der Mikrophone aufnehmen und daraus mittels der Steuereinheit die Sollfrequenz ermitteln, und
• - die übrigen Vorrichtungen anschließend Ultraschall mit der Sollfrequenz einkoppeln.

For example, the cleaning is carried out with a plurality of devices, with the frequencies of the ultrasound coupled into the body from the respective first ultrasound generators being matched first, in that:

• - a first device couples ultrasound with a target frequency,
• - The other devices record the injected ultrasound using the microphones and use the control unit to determine the desired frequency, and
• - The other devices then couple ultrasound with the desired frequency.

If a sufficient number of devices are used and placed appropriately, a large ship's hull, for example a cargo ship or ferry, can be cleaned over its entire surface below the waterline using the method according to the invention.

In addition to being used for cleaning ship hulls, the device according to the invention and the method according to the invention can also be used for cleaning the inner wall of pipelines, in particular pipelines.

character list

• 1: eine schematische Querschnittsansicht eines Ausführungsbeispiels der erfindungsgemäßen Vorrichtung, und
• 2a, 2b: schematische Ansichten eines Schiffsrumpfs mit erfindungsgemäßen Vorrichtungen zur Demonstration des erfindungsgemäßen Verfahrens.

Further measures improving the invention are presented in more detail below together with the description of a preferred exemplary embodiment of the invention with reference to the figures. It shows:

• 1 : a schematic cross-sectional view of an embodiment of the device according to the invention, and
• 2a , 2 B 1: schematic views of a ship's hull with devices according to the invention for demonstrating the method according to the invention.

1 shows a schematic half section of a device 100 according to the invention for cleaning a surface of a body around which a fluid flows, in particular a ship hull around which water flows.

The device comprises the first ultrasound generator 1 for coupling ultrasound into the body and the holding system 2 for stationary fastening of the device 100 on the surface to be cleaned. The holding system 2 is designed as a magnetic holding system for the detachable attachment of the device 100 and includes the two permanent magnets 21, the undersides of which are intended to rest on the surface to be cleaned. The first ultrasonic generator 1 is in direct physical contact with the front permanent magnet 21 so that ultrasonic excitations can be coupled into the body to be cleaned via the permanent magnet 21 .

The device also includes the second ultrasonic generator 7, which is set up to emit ultrasound into the surrounding fluid, with the main emission direction of the ultrasound preferably lying in a plane parallel to the surface to be cleaned. As a result, in addition to the vibrational excitation of the surface to be cleaned, which is generated by the first ultrasonic generator 1, a cavitation layer close to the surface is generated in the fluid flowing around, so that a combined cleaning effect occurs.

The means for self-sufficient operation of the electrical consumers of the device 100 include the turbine 5, the generator 6 and the accumulator 3, the electrical generator 6 being able to be driven by the turbine 5 and being set up to charge the accumulator 3. Electrical connection lines between the various components of the device 100 are not shown for the sake of clarity. The impeller 51 of the turbine 5 is shown in a working position for being driven by a fluid flowing around it. For example, the bucket wheel can be designed to be pivotable, for example into a rest position pivoted by 90°.

The microphone 9 for recording ultrasound is used for frequency adjustment during the simultaneous operation of a plurality of devices 100 according to the invention within the scope of the method according to the invention. The control unit 10 is set up to carry out all the steps necessary for the appropriate and autonomous operation of the device 100, in particular to output control signals to the ultrasonic transmitters 1, 7 and to evaluate the recordings of the microphone 9.

The pull-off device 8 serves to detach the device 100 from the surface to be cleaned against the holding force of the holding system 2 and is designed as a system of two extendable spindles 81 arranged in the vicinity of the permanent magnets 21 .

The torpedo-shaped housing 4 is designed to be media-tight, in particular waterproof, to protect the components it accommodates. The length of the housing 4 is, for example, approximately 1 m for an application of the device 100 for cleaning a ship's hull.

The 2a and 2 B show schematic views for demonstrating the method according to the invention for cleaning a surface of a ship's hull S around which water W flows, using the three devices 100.1, 100.2, 100.3 according to the invention. The devices 100.1, 100.2, 100.3 are fixed in place below the waterline and at regular intervals from one another on the ship's hull S to be cleaned by means of the holding systems. The proportions shown are purely schematic and selected for the purpose of clear illustration. For example, the devices 100.1, 100.2, 100.3 are positioned in such a way that a full surface cleaning of the entire underwater hull is guaranteed. For example, when operating first ultrasonic generators with a power of up to 100 W and second ultrasonic generators with a power of up to 1 kW, there is a sufficient cleaning effect in a range of approx.

In 2a an operating state is shown in which the first device 100.1 couples ultrasound with a target frequency into the ship's hull S, while the two other devices 100.2, 100.3 use the microphones to record the coupled-in ultrasound in order to use the control unit to determine the target frequency.

In the in the 2 B In the operating state shown, all devices 100.1, 100.2, 100.3 couple ultrasound with the target frequency into the ship's hull S by means of the first ultrasound transmitter and at the same time ultrasound is emitted by means of the second ultrasonic transmitter into the circulating water W, whereby a cleaning cavitation layer in the border area to the ship's hull S is also generated.

The implementation of the invention is not limited to the preferred exemplary embodiments specified above. Rather, a number of variants are conceivable which make use of the solution shown even in the case of fundamentally different designs. All features and/or advantages resulting from the claims, the description or the drawings, including structural details, spatial arrangements and method steps, can be essential to the invention both on their own and in a wide variety of combinations.

Reference List

100

contraption

1

first ultrasound generator

2

retention system

21

permanent magnet

3

accumulator

4

Housing

5

turbine

51

paddle wheel

6

electric generator

7

second ultrasonic transducer

8th

puller

81

spindle

9

microphone

10

control unit

S

hull

W

Water

Claims (11)

Device (100) for cleaning a surface of a body around which a fluid flows, in particular a ship's hull (S) around which water (W) flows, comprising a first ultrasound transmitter (1) for coupling ultrasound into the body, characterized in that the device ( 100) comprises means for autonomous operation of the first ultrasonic generator (1) and a holding system (2) for stationary attachment of the device (100) on the surface to be cleaned. Device (100) according to claim 1 , characterized in that the means for self-sufficient operation comprise a turbine (5) for extracting flow energy from the fluid flowing around, an electric generator (6) and an accumulator (3), the electric generator (6) being powered by the turbine (5 ) can be driven and is set up to charge the accumulator (3). Device (100) according to claim 2 , characterized in that the impeller (51) of the turbine (5) is pivotable between a working position and a rest position. Device (100) according to one of the preceding claims, characterized in that the holding system (2) is designed as a magnetic holding system for the detachable fastening of the device (100). Device (100) according to one of the preceding claims, characterized in that the device (100) comprises a medium-tight housing (4), the housing in particular preferably having a torpedo-shaped form. Device (100) according to one of the preceding claims, characterized in that the device (100) has a second ultrasound generator (7) which is set up to emit ultrasound into the surrounding fluid. Device (100) according to one of the preceding claims, characterized in that the device (100) has a removal device (8) by means of which the device (100) can be detached from the surface to be cleaned against the holding force of the holding system (2). Device (100) according to one of the preceding claims, characterized in that the device (100) has a microphone (9) which is set up to record ultrasound from the body. Device (100) according to one of the preceding claims, characterized in that the device (100) has a control unit (10) for controlling the electrically operated components of the device (100). Method for cleaning a body surface around which a fluid flows, in particular a ship hull (S) around which water (W) flows, characterized in that the cleaning is carried out by means of at least one device (100) according to one of the preceding claims, the device ( 100) is fixed in place on the surface to be cleaned by means of the holding system (2) and ultrasound is coupled into the body by means of the first ultrasonic generator (1) and/or by means of the second Ultrasonic transducer (7) ultrasound is emitted into the fluid flowing around. procedure after claim 10 , characterized in that the cleaning is carried out with a plurality of devices (100.1, 100.2, 100.3), the frequencies of the ultrasound coupled into the body from the respective first ultrasound generators (1) being initially matched by: - a first Device (100.1) couples in ultrasound with a target frequency, - the other devices (100.2, 100.3) pick up the coupled-in ultrasound from the body using the microphones (10) and use the control unit (9) to determine the target frequency, and - the other devices ( 100.2, 100.3) then couple in ultrasound with the desired frequency.

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