EP3705391A1 - Watercraft with heat exchanger and ultrasonic cleaning of the heat exchanger - Google Patents

Abstract

The present invention relates to a watercraft with a heat exchanger 10, the heat exchanger 10 having a first area for a first fluid and a second area for a second fluid, the second area being connectable to the boat environment and the second fluid being ambient water, the Heat exchanger 10 has a first ultrasonic transducer 20 and a second ultrasonic transducer 20, the first ultrasonic transducer 20 and the second ultrasonic transducer 20 being designed to convert electrical energy into ultrasound, at least the second ultrasonic transducer 20 being designed to convert ultrasound into electrical energy.

Description

The invention relates to a watercraft with a heat exchanger, the heat exchanger using water from the environment as a medium. As a result, the heat exchanger is regularly contaminated, which means a reduction in both the amount of water flowing through and the amount of heat transferred. On the one hand, this can be due to deposits such as limescale deposits. However, the growth of marine animals, algae, smallpox and the like is much more important.

In a watercraft, chemical cleaning is regularly ruled out, as the chemicals used for cleaning would be released directly into the environment and this would directly pollute the ecosystem. In addition, it is precisely in closed spaces, such as are common on board a watercraft, that dangerous gas mixtures can develop, which, for example, can be toxic, flammable and / or corrosive. On board a submarine, this point is even more important, since there is no possibility of venting when the submarine is operating submerged.

In order to remove these deposits from a heat exchanger, the heat exchanger must be mechanically cleaned regularly. To do this, the heat exchanger must be disassembled. If the watercraft is a submarine, the heat exchanger must be able to withstand the immersion pressure of the submarine. This also means that a new pressure test is necessary after subsequent assembly, since the heat exchanger represents an interface to the ambient pressure outside the submarine. So every work on a heat exchanger is of course always a certain safety risk for the submarine and its diving ability. Furthermore, this work is extremely difficult and time-consuming, especially in a cramped submarine, and lengthens lay times.

Another problem naturally arises from the fact that biological material in the cooling water of the heat exchanger moves from one area of the world to another can be transported. This leads to a global distribution of certain species and thus regularly to a burden on the ecosystem.

The object of the invention is to provide a watercraft with a heat exchanger, in which opening the heat exchanger for cleaning can be dispensed with.

This object is achieved by a watercraft with the features specified in claim 1 and by a method with the features specified in claim 10. Advantageous developments result from the subclaims, the following description and the drawings.

The watercraft according to the invention has a heat exchanger. The heat exchanger has a first area for a first fluid and a second area for a second fluid. The first fluid can be, for example, a cooling liquid from a boat engine, an air conditioning system, an electronic device, a battery system or any other desired heat-emitting or heat-absorbing device on board the watercraft. The heat-emitting device can also be a further heat exchanger which is connected to a further cooling circuit, the further cooling circuit being filled with a third fluid. The first fluid can for example be water but also an oil. The first fluid is regularly conducted in a closed circuit within the watercraft.

The second area can be connected to the boat environment. The second area can also be regularly separated from the boat environment, the water, for example by closing a valve. This is advantageous when the watercraft has to be taken out of the water for maintenance or repair purposes, for example. In normal operation, however, the second area is fluidically connected to the boat environment and therefore does not represent a closed circuit. The second fluid is therefore ambient water, for example and in particular sea water. The heat exchanger has a first ultrasonic transducer and a second ultrasonic transducer. The first ultrasonic transducer and the second Ultrasonic transducers are designed to convert electrical energy into ultrasound. At least the second ultrasonic transducer is designed to convert ultrasound into electrical energy.

As the second ultrasound receiver can be used both as a transmitter and as a receiver, detection is also possible in addition to cleaning. In this way, the need for cleaning can also be determined locally resolved. This is important because the first ultrasonic transducer and the second ultrasonic transducer cannot regularly be used during a mission of the watercraft. It is therefore also not possible to carry out a simple time-controlled cleaning, as is typically provided in commercially available cleaning systems.

While ultrasonic cleaners can now be regarded as common in the chemical industry, their use on a watercraft, especially on a submarine, is to be avoided at all costs, since the ultrasound generates and destroys cavities, which is associated with sound emissions. Both the emission of the ultrasound per se and, in particular, the sound emission from collapsing cavities must be avoided in order not to make it easier to locate the watercraft.

Thus, by using the first ultrasonic transducer as a transmitter and the second ultrasonic transducer as a receiver, an analysis can initially be carried out so that cleaning can be carried out as a function of the actual contamination.

The watercraft is preferably a military watercraft. The watercraft is particularly preferably a submarine.

In a further embodiment of the invention, the heat exchanger has a cylindrical container, the first ultrasonic transducer and the second ultrasonic transducer being arranged outside the container. The container and the first ultrasonic transducer are connected in a sound-transmitting manner by means of a first sound transmitter. The container and the second ultrasonic transducer are analogous connected sound-transmitting by means of a second sound transmitter. This embodiment is preferred since the heat exchanger represents a connection between the surroundings of the watercraft and the interior of the watercraft. Thus, if the watercraft is a submarine, the heat exchanger must be able to withstand even the maximum diving pressure of the submarine. This means that the cylindrical outer wall of the container must be designed accordingly. An ultrasonic transducer usually has a flat surface of the emitter, which therefore cannot be applied directly to the round wall. Therefore, a component which on the one hand clings optimally to the curve of the cylindrical container and on the other hand has a flat surface for receiving the sound transmitter is optimal. The sound transmitter made of metal is preferred, since metal is a very good sound conductor. For technical reasons, the heat exchanger tank is optimally made of steel. The sound transmitter can be made of a different metal, especially since the sound transmitter does not come into contact with water. Here the material of the sound transmitter can be selected to optimize the processing, for example the sound transmitter can be made of aluminum.

In a further embodiment of the invention, the heat exchanger has a first group of first ultrasonic transducers, all first ultrasonic transducers being connected to the container in a sound-transmitting manner via the first sound transducer. The heat exchanger also has a second group of second ultrasonic transducers, all of the second ultrasonic transducers being connected to the container in a sound-transmitting manner via the second sound transmitter. For example and in particular, the sound transducers are rod-shaped and shaped for assembly in the longitudinal direction of the container.

In a further embodiment of the invention, the heat exchanger has a third group of third ultrasonic transducers, all third ultrasonic transducers being connected to the container in a sound-transmitting manner via a third sound transducer. The groups of ultrasonic transducers are arranged in the longitudinal direction of the heat exchanger. An angle of 120 ° ± 20 ° is preferably formed between the groups. The sum of all angles is 360 °.

In a further embodiment of the invention, the heat exchanger is a tube bundle heat exchanger.

In a further alternative embodiment of the invention, the first ultrasonic transducer and the second ultrasonic transducer are arranged in the interior of the heat exchanger. The heat exchanger is preferably a tube bundle heat exchanger. In this case, the first ultrasonic transducer and the second ultrasonic transducer can be elongated and arranged in parallel between the tubes of the tube bundle heat exchanger. This has the advantage that the ultrasound is introduced directly into the heat exchanger. On the other hand, it is disadvantageous that pressure hull bushings have to be kept for the energy supply. On the other hand, there may be contact between the ultrasonic transducer and the surrounding water.

Of course, a heat exchanger can have ultrasonic transducers both on the inside and on the outside.

In a further embodiment of the invention, the heat exchanger is a tube bundle heat exchanger, further ultrasonic transducers being arranged in the area of the inlet zone and the outlet zone. The inlet zone and the outlet zone of a tube bundle heat exchanger are the areas in which fluid is fed into or withdrawn from the tubes lying parallel to one another. These areas have an increased potential for organisms to grow. It is therefore advantageous to introduce more energy into these areas in particular, which can easily be achieved by increasing the number of ultrasonic transducers. For example and in particular, the number of ultrasonic transducers in the area of the inlet zone and the outlet zone is doubled.

In a further embodiment of the invention, the ultrasonic transducers are designed to emit at least one frequency of ultrasound in the frequency range from 20 kHz to 1 MHz, preferably from 20 kHz to 120 kHz, particularly preferably from 20 kHz to 50 kHz.

In a further embodiment of the invention, the ultrasonic transducers are designed to emit different frequencies, the frequencies of the different ultrasonic transducers differing by at most 10%, preferably by at most 2%, particularly preferably by at most 0.5%. For example and preferably, the frequency of the different ultrasonic transducers differs by 1 Hz multiplied by the number of ultrasonic transducers. The slightly different frequencies result in vibrations, which changes the superimposition pattern of the various ultrasonic waves and leads to energy peaks and thus to cavities and thus to the cleaning effect in other spatial areas. In this way, the cleaning effect can be made more uniform over all areas of the heat exchanger.

In a further embodiment of the invention, the first ultrasonic transducer is designed to emit a first fixed frequency and the second ultrasonic transducer is designed to emit a second, variable frequency.

In a further embodiment of the invention, the ultrasonic transducers are designed to emit different frequencies, the frequencies of the individual ultrasonic transducers being changed cyclically while rotating.

In a further embodiment of the invention, the ultrasonic transducers can be controlled in such a way that the phase of the emitted ultrasonic waves can be set.

In a further embodiment of the invention, the watercraft has a first pressure sensor and a second pressure sensor in the second fluid, the first pressure sensor being arranged in front of the heat exchanger and the second pressure sensor being arranged behind the heat exchanger. This enables the pressure loss across the heat exchanger to be determined. The growth of limescale or microorganisms leads to a reduction in the cross-section through which the air flows and thus to an increased pressure loss.

In a further embodiment of the invention, the watercraft has a control device for controlling the first ultrasonic transducer and the second ultrasonic transducer, the control device being designed to change the phase position of the emitted ultrasonic waves of the first ultrasonic transducer relative to the emitted ultrasonic waves of the second ultrasonic transducer. Depending on the phase position of the emitted ultrasonic waves, different interference patterns are formed, with a maximum of different points being reached in which cavities in particular are formed and thus the cleaning effect is increased. By changing the phase position, you change the interference pattern and thus the area in which a maximum cleaning effect is achieved.

In a further embodiment of the invention, the heat exchanger has a length of 2 m to 4 m and a diameter of 0.5 m to 1 m.

The submarine is particularly preferably a military submarine.

1. a) Feststellen einer Verschmutzung des Wärmetauschers,
2. b) Emittieren von Ultraschall mittels des ersten Ultraschallwandlers und des zweiten Ultraschallwandlers zur Reinigung des Wärmetauschers.

In a further aspect, the invention relates to a method for cleaning a heat exchanger on board a watercraft according to the invention, the method having the following steps:

1. a) detection of contamination of the heat exchanger,
2. b) emitting ultrasound by means of the first ultrasonic transducer and the second ultrasonic transducer for cleaning the heat exchanger.

Since automatic or regular cleaning is not possible on board a watercraft, in particular a submarine, in order not to reveal the position of the watercraft, in particular the submarine, through the noise emission in the event of a mission, the degree of soiling of the heat exchanger is therefore unknown at the start of cleaning. It is therefore not clear at the start of cleaning whether cleaning is required or to what extent cleaning is required. Therefore, first of all, it is necessary to determine the level of contamination, the degree of contamination or the position of the contamination.

• c) Emittieren eines ersten Ultraschallsignals mit dem ersten Ultraschallwandler,
• d) Empfangen eines veränderten ersten Ultraschallsignals mit dem zweiten Ultraschallwandler.

In a further embodiment of the invention, the determination of contamination of the heat exchanger in step a) comprises the following steps:

• c) emitting a first ultrasonic signal with the first ultrasonic transducer,
• d) receiving a modified first ultrasonic signal with the second ultrasonic transducer.

Buildup, for example lime or microorganisms, influence the sound and also lead to other interferences due to shifted phase transitions. This means that detection by means of ultrasound is comparatively well possible. By using at least one ultrasonic transducer as a transmitter and another ultrasonic transducer as a receiver, contamination can be detected. The functionality can then preferably be reversed so that the second ultrasonic transducer works as an emitter and the first ultrasonic transducer as a receiver. A third ultrasonic transducer is also preferably used as an emitter and / or receiver.

• e) Messen eines ersten Drucks mittels des ersten Drucksensors,
• f) Messen eines zweiten Drucks mittels des zweiten Drucksensors,
• g) Ermitteln der Differenz zwischen dem ersten Druck und den zweiten Druck,
• h) Vergleichen der Differenz mit einer Toleranzschwelle.

In a further embodiment of the invention, the determination of contamination of the heat exchanger in step a) comprises the following steps:

• e) measuring a first pressure by means of the first pressure sensor,
• f) measuring a second pressure by means of the second pressure sensor,
• g) determining the difference between the first pressure and the second pressure,
• h) comparing the difference with a tolerance threshold.

This method has the great advantage that it can be carried out continuously and without noise emission. In particular, this can be carried out in addition to the aforementioned method steps.

In a further embodiment of the invention, in step b) ultrasound is imitated by means of a third ultrasonic transducer for cleaning the heat exchanger, the phase relationship of the ultrasonic waves emitted by the first ultrasonic transducer, the second ultrasonic transducer and the third ultrasonic transducer being varied. This variation of the phase relationship makes it possible to locally vary energy maxima by superimposing the ultrasonic waves thus changing the areas of optimal cleaning and thus completely cleaning all areas of the heat exchanger.

In a further embodiment of the invention, in step b) a higher energy input into the inlet zone and / or outlet zone of the heat exchanger takes place by means of ultrasound. Since an increased need for cleaning is to be expected here, it is expedient to enter a particularly large amount of energy into these areas in order to accelerate the cleaning.

In a further embodiment of the invention, a cleaning fluid is added to the second fluid before or during step b). It is particularly preferably a completely environmentally friendly cleaning fluid, since this is released into the environment unchanged.

In a further embodiment of the invention, the method is carried out at a non-mission critical time, in particular during transfer trips or idle times. Execution during a transfer trip has the additional advantage that microorganisms are also killed, which could otherwise be transported to other areas by the ambient water taken up. The ingestion of sea water enables the unwanted transport of biological material and thus the transfer of species to non-species-specific areas. Ultrasonic cleaning kills this material, which means that contamination can be avoided.

• i) Emittieren eines dritten Ultraschallsignals mit einem dritten Ultraschallwandler,
• j) Empfangen eines veränderten dritten Ultraschallsignals mit dem zweiten Ultraschallwandler,
• k) lokalisieren einer Verunreinigung aus den in Schritt d) und Schritt j) empfangenen Daten.

In a further embodiment of the invention, the method additionally has the following steps:

• i) emitting a third ultrasonic signal with a third ultrasonic transducer,
• j) receiving a modified third ultrasonic signal with the second ultrasonic transducer,
• k) locating an impurity from the data received in step d) and step j).

In a further embodiment of the invention of the method, the frequency and / or phase of the ultrasonic waves emitted by the ultrasonic emitters are changed over time and the contamination is determined as a function of frequency and / or phase. The cleaning effect is determined and stored as a function of frequency and / or phase by variations, in particular by random variations. For the next cleaning cycle, the system uses the optimum operating point from the last cleaning as the starting point. Optionally and preferably, a random adjustment of frequency and / or phase takes place again and the result of the cleaning effect is determined and the dependency is stored. In this way the system can adapt itself. Particularly preferably, the geographic position of the watercraft is also stored and taken into account. Since different conditions exist in different marine biotopes, the vegetation in particular can differ greatly and thus favor different cleaning procedures.

In a further embodiment of the invention, the method is carried out in an automated manner, in particular the method is carried out on a self-learning system.

• Fig. 1 Wärmetauscher im Längsschnitt
• Fig. 2 Schallüberträger im Querschnitt
• Fig. 3 Rohrbündelwärmetaucher im Querschnitt
• Fig. 4 Rohrbündelwärmetauscher mit drei Querschnitten
• Fig. 5 Rohrbündelwärmetauscher mit internen Ultraschallwandlern

The heat exchanger according to the invention is explained in more detail below on the basis of an exemplary embodiment shown in the drawings.

• Fig. 1 Longitudinal section of the heat exchanger
• Fig. 2 Sound transmitter in cross section
• Fig. 3 Tube bundle heat exchanger in cross section
• Fig. 4 Tube bundle heat exchanger with three cross-sections
• Fig. 5 Tube bundle heat exchanger with internal ultrasonic transducers

In Fig. 1 a heat exchanger 10 is shown in longitudinal section. On the side of the outer wall there are two sound transmitters 30, on each of which a group of four ultrasonic transducers 20 are arranged.

Fig. 2 shows a sound transmitter 30 in cross section with an ultrasonic transducer 20. The curvature of the sound transmitter 30, with which it can nestle against the outer wall of the heat exchanger 10, is clearly visible.

In Fig. 3 a cross section of a heat exchanger 10 is shown in the form of a tube bundle heat exchanger. Here four groups of ultrasonic transducers 20 are arranged on four sound transducers 30 at right angles to one another. Various tubes 40 are arranged in the interior of the heat exchanger 10. A heat transfer occurs between the second fluid flowing in the tubes 40 and the first fluid flowing inside the heat exchanger 10 outside the tubes 40.

Fig. 4 shows three separate cross-sections through a heat exchanger 10. The upper cross-section shows the inlet, the lower cross-section shows the outlet into the pipes 40. Since increased contamination is to be expected here, the number of ultrasonic transducers 20 is doubled in these areas. To mount the ultrasonic transducers 20 in these areas, the number of sound transmitters 30 is correspondingly doubled.

In the Fig. 3 and Fig. 4 The examples shown each have an angle of 90 ° between the four ultrasonic transducers 20, or an angle of 45 ° in each case for eight ultrasonic transducers 20. However, three ultrasonic transducers 20 at an angle of 120 ° or six ultrasonic transducers 20 at an angle of 60 ° can also preferably be used.

Fig. 5 FIG. 14 shows an example in which three ultrasonic transducers 20 are arranged in the interior of the heat exchanger 10 between the tubes 40.

10

Wärmetauscher

20

Ultraschallwandler

30

Schallüberträger

40

Rohr

Reference number

10

Heat exchanger

20th

Ultrasonic transducer

30th

Sound transmitter

40

pipe

Claims (15)

Watercraft with a heat exchanger (10), the heat exchanger (10) having a first area for a first fluid and a second area for a second fluid, the second area being connectable to the boat environment and the second fluid being ambient water, the heat exchanger (10) has a first ultrasonic transducer (20) and a second ultrasonic transducer (20), the first ultrasonic transducer (20) and the second ultrasonic transducer (20) being designed for converting electrical energy into ultrasound, with at least the second ultrasonic transducer (20) is designed to convert ultrasound into electrical energy. Watercraft according to claim 1, characterized in that the heat exchanger (10) has a cylindrical container, the first ultrasonic transducer (20) and the second ultrasonic transducer (20) being arranged outside the container, the container and the first ultrasonic transducer (20) transmitting sound are connected by means of a first sound transmitter (30), the container and the second ultrasonic transducer (20) being connected in a sound-transmitting manner by means of a second sound transmitter (30). Watercraft according to Claim 2, characterized in that the heat exchanger (10) has a first group of first ultrasonic transducers (20), all first ultrasonic transducers (20) being connected to the container in a sound-transmitting manner via the first sound transducer (30), the heat exchanger ( 10) has a second group of second ultrasonic transducers (20), all second ultrasonic transducers (20) being connected to the container in a sound-transmitting manner via the second sound transducer (30). Watercraft according to claim 3, characterized in that the heat exchanger (10) has a third group of third ultrasonic transducers (20), all third ultrasonic transducers (20) being connected to the container in a sound-transmitting manner via a third sound transducer (30), the groups of Ultrasonic transducers (20) in the longitudinal direction of the heat exchanger (10) are arranged, an angle of 120 ° ± 20 ° being formed between the groups. Watercraft according to claim 1, characterized in that the first ultrasonic transducer (20) and the second ultrasonic transducer (20) are arranged in the interior of the heat exchanger (10). Watercraft according to one of the preceding claims, characterized in that the heat exchanger (10) is a tube bundle heat exchanger, the first ultrasonic transducer (20) and the second ultrasonic transducer (20) being elongated, the first ultrasonic transducer (20) and the second ultrasonic transducer ( 20) are arranged in parallel between the tubes of the tube bundle heat exchanger. Watercraft according to one of the preceding claims, characterized in that the watercraft has a first pressure sensor and a second pressure sensor in the second fluid, the first pressure sensor being arranged in front of the heat exchanger (10) and the second pressure sensor behind the heat exchanger (10). Watercraft according to one of the preceding claims, characterized in that the watercraft has a control device for controlling the first ultrasonic transducer (20) and the second ultrasonic transducer (20), the control device for changing the phase position of the emitted ultrasonic waves of the first ultrasonic transducer (20) the relative is designed to the emitted ultrasonic waves of the second ultrasonic transducer (20). Method for cleaning a heat exchanger (10) on board a watercraft according to one of the preceding claims, characterized in that the method comprises the following steps: a) detection of contamination of the heat exchanger (10), b) emitting ultrasound by means of the first ultrasonic transducer and the second ultrasonic transducer (20) for cleaning the heat exchanger (10). Method according to Claim 9, characterized in that the determination of contamination of the heat exchanger (10) in step a) comprises the following steps: c) emitting a first ultrasonic signal with the first ultrasonic transducer (20), d) receiving a modified first ultrasonic signal with the second ultrasonic transducer (20). Method according to one of Claims 9 to 10, characterized in that the determination of contamination of the heat exchanger (10) in step a) comprises the following steps: e) measuring a first pressure by means of the first pressure sensor, f) measuring a second pressure by means of the second pressure sensor, g) determining the difference between the first pressure and the second pressure, h) comparing the difference with a tolerance threshold. A method according to one of claims 9 to 11, characterized in that in step b) ultrasound is imitated by means of a third ultrasonic transducer (20) for cleaning the heat exchanger (10), the phase relationship of the first ultrasonic transducer (20), the second ultrasonic transducer (20) and the third ultrasonic transducer (20) emitted ultrasonic waves is varied. Method according to one of Claims 9 to 12, characterized in that in step b) a higher energy input into the inlet zone and / or outlet zone of the heat exchanger (10) takes place by means of ultrasound. Method according to one of Claims 9 to 13, characterized in that a cleaning fluid is added to the second fluid before or during step b). Method according to Claim 10 and one of Claims 11 to 14, characterized in that the method additionally has the following steps: i) emitting a third ultrasonic signal with a third ultrasonic transducer (20), j) receiving a modified third ultrasonic signal with the second ultrasonic transducer (20), k) locating an impurity from the data received in step d) and step j).

Images