EP3650793A1 - Method and device for cleaning air coolers - Google Patents

Abstract

The method for cleaning an air cooler of a large industrial plant, the air cooler having at least one field with at least two layers of pipes (20), these pipes (20) run in a straight line, the pipes (20) of all layers run parallel to one another, the pipes ( 20) of a second layer located under a first layer are each arranged in a gap between two tubes (20) of the first layer, so that each tube (20) of the first layer and a tube (20) of the second layer located obliquely below it Inclined planes (30, 32), which are parallel to one another, with the following method steps: a) Providing a nozzle bar (34) which has a large number of outlet nozzles (40) which are arranged on a straight line and main jet directions (44 ), b) arranging the nozzle bar (34) on a carrier (54) of the air cooler, c) aligning the main jet directions (44) of the outlet nozzles (40) parallel to one first inclined plane (30), d) feeding water under pressure into the nozzle beam (34), so that the water exits under pressure from the outlet nozzles (40) parallel to the inclined plane (30), unde) moving the nozzle beam (34) over the Surface.

Description

A large industrial plant is understood to mean plants in the chemical and in particular petrochemical industry, furthermore plants and plants in the drying and power plant industry, and e.g. understood for refineries, waste incineration plants and power plant areas. Air coolers are used in such systems for the targeted cooling of fluids. In order to be able to maintain a process temperature of a fluid in a system, it is necessary from time to time to specifically cool the fluids supplied to the process, provided that they are too high due to any event. The temperature of these fluids can be specifically reduced by the desired amount using an air cooler. Depending on the required temperature reduction, the fluid to be cooled flows through more or less of the individual areas of at least one air cooler. The desired reduction is achieved quickly and specifically. An example of the fluids are water, oil, steam and chemicals.

Such air coolers are relatively large devices. They are usually set up outdoors. They are in contact with the ambient air so they can flow through them. They are often assigned fans that provide additional flow. The cooling can also be influenced and specifically adjusted via the fans.

The air coolers have at least two layers, each with a large number of tubes. The fluid to be cooled flows through the pipes. The pipes run in a straight line. The pipes of all layers run parallel to each other. The tubes of a first layer, which forms the surface of the air cooler, run in a first plane. The tubes of a second layer underneath run in a second plane, which is parallel to the first plane. A tube of the second layer is arranged on a gap between two tubes of the first layer. If a third layer is provided, this is arranged in a third plane, its tubes are each at right angles below the tubes of the first layer and thus again at a gap to the tubes of the second layer. Adjacent levels are usually the same distance apart for all levels, measured perpendicular to the level. There are often three or five layers.

An air cooler has at least one field with two or more such layers. Often it has several fields, which are usually identical to one another. The fields are arranged in one field level. For example, there are air coolers with two fields, the two fields are arranged like a roof.

From the DE 19 42 157 A1 an air cooler is known which has four layers of pipes, the pipes run in a straight line and have the same length, the pipes of all layers run parallel to one another, the pipes of a first layer, which forms the surface of the air cooler, run in a first plane, the pipes of the second layer underneath run in a second plane that is parallel to the first plane, etc.

From the DE 22 25 915 A1 an air cooler is known, which is arranged in a housing. It has two layers, each with obviously only one, probably spiraling pipe. The tube of the upper layer runs in a first plane, the tube of the second layer below it runs in a second plane, which is parallel to the first plane. The tube of the second layer is arranged on a gap between two revolutions of the tube of the first layer.

From the US 2009/0314481 A1 a position of an air cooler is known, the seven tubes shown are of equal length, run parallel to one another and in a common plane.

Due to the outdoor installation and / or the flow of air, dirt accumulates on the surfaces of the pipes of the air cooler over time. As a result, the heat exchange of the surface with the ambient air is no longer as good as it was when the air cooler was new. It is therefore necessary to clean the air cooler from time to time. According to the prior art, this is done via a nozzle carriage which has a number of nozzles from which a plurality of parallel water jets which are arranged in a straight line emerge. The work is typically carried out at a pressure of 100-200 bar. The air coolers often have a mobile carrier which can be moved parallel to the surface of the air cooler and is arranged on the latter. For cleaning purposes, a ladder is attached to the carrier, on which the nozzle carriage is guided in a longitudinally displaceable manner. The jet car has a motor for its movement, mostly a pneumatic motor. The air cooler is cleaned in strips, for this purpose the carrier or the nozzle carriage is moved along the ladder. A new Streak is then achieved by moving the nozzle carriage or carrier to a different position.

A disadvantage of the previously known cleaning method is that the strips each cover only a smaller part of the surface. Many movements therefore have to be carried out in order to be able to clean the entire air cooler. It is also noteworthy here that the previously known nozzle carriage has about ten nozzles. The strip width is limited by this number, for example ten nozzles.

This is where the invention comes in. It has set itself the task of simplifying the previously known cleaning process, allowing it to run faster and improving it overall. Parts of the device required for cleaning are to be saved. Furthermore, the cleaning should be carried out more effectively, in particular at least the second layer and other layers that may be located below it should be cleaned better.

1. a) Bereitstellen eines Düsenbalkens, der eine große Anzahl von Austrittsdüsen aufweist, die auf einer geraden Linie angeordnet sind und zueinander parallele Hauptstrahlrichtungen haben,
2. b) Anordnen des Düsenbalkens an einem Träger des Luftkühlers, soweit vorhanden, oder am Luftkühler selbst, und Ermöglichen einer gesteuerten Verschiebbarkeit des Düsenbalkens parallel zur Oberfläche des Luftkühlers und oberhalb dieser,
3. c) Ausrichten der Hauptstrahlrichtungen der Austrittsdüsen parallel zu einer ersten Schrägebene,
4. d) Einspeisen von Wasser unter Druck in den Düsenbalken, so das Wasser unter Druck aus den Austrittsdüsen parallel zu der Schrägebene austritt, und
5. e) Verschieben des Düsenbalkens über die Oberfläche.

This object is achieved by a method for cleaning an air cooler of a large industrial plant, the air cooler having at least one field with at least two layers of pipes, these pipes run in a straight line, the pipes of all layers run parallel to one another, the pipes of a first layer, the the surface of the air cooler forms, run in a first plane, the pipes of an underlying second layer run in a second plane which is parallel to the first plane and a pipe of the second layer is arranged on a gap between two pipes of the first layer, so that each tube of the first layer and a tube of the second layer located diagonally below are in inclined planes that are parallel to one another, with the following process steps:

1. a) providing a nozzle bar which has a large number of outlet nozzles which are arranged on a straight line and have main jet directions parallel to one another,
2. b) arranging the nozzle bar on a carrier of the air cooler, if present, or on the air cooler itself, and enabling controlled movement of the nozzle bar parallel to and above the surface of the air cooler,
3. c) aligning the main jet directions of the outlet nozzles parallel to a first inclined plane,
4. d) feeding water under pressure into the nozzle bar so that the water exits under pressure from the outlet nozzles parallel to the inclined plane, and
5. e) moving the nozzle bar across the surface.

With this method, the strips in which the cleaning takes place can be made much wider than before. They advantageously extend over the entire dimension of the field, so that the field only has to be run over once. However, it is advantageously run over a second time, in particular on the way back, in this case the main jet directions of the outlet nozzles are aligned parallel to a second inclined plane, which runs at the same value of its angle to the surface as the first inclined plane, but is different from the first inclined plane .

The invention has the advantage that the water jets are directed at the spaces between the tubes of the individual layer and not, as in the prior art, at right angles to the surface and thus essentially at the tubes. Even in fields with two layers, especially in fields with more than two layers, better cleaning of the lower pipes, i.e. the lower layers, has a positive effect.

1. A) einen Düsenbalken, der eine große Anzahl von Austrittsdüsen aufweist, die auf einer geraden Linie angeordnet sind und zueinander parallele Hauptstrahlrichtungen haben, und der ein Anschlussende hat, das mit einer Zuleitung für Druckwasser verbunden werden kann,
2. B) eine Haltevorrichtung für die Aufnahme des Düsenbalkens, die eine Bewegungsvorrichtung zum Verschieben des Düsenbalkens parallel zur Oberfläche des Luftkühlers und eine Drehvorrichtung für eine Drehbewegung des Düsenbalkens um seine Längsachse aufweist, und die eine Befestigungsvorrichtung für die Anordnung am Luftkühler hat.

In terms of the device, the object is achieved by a device for cleaning an air cooler of a large industrial plant, the air cooler having at least one field with at least two layers of pipes, these pipes run in a straight line, the pipes of all layers run parallel to one another, the pipes of a first layer, which forms the surface of the air cooler, run in a first plane, the pipes of an underlying second layer run in a second plane which is parallel to the first plane and in each case a pipe of the second layer is arranged on a gap between two pipes of the first layer , so that each tube of the first layer and an obliquely below it tube of the second layer are in inclined planes that are parallel to each other, the device has

1. A) a nozzle bar, which has a large number of outlet nozzles, which are arranged on a straight line and parallel to each other Have main jet directions, and which has a connection end that can be connected to a supply line for pressurized water,
2. B) a holding device for receiving the nozzle bar, which has a movement device for displacing the nozzle bar parallel to the surface of the air cooler and a rotating device for rotating the nozzle bar about its longitudinal axis, and which has a fastening device for arrangement on the air cooler.

This device does not require a nozzle carriage and therefore no drive for a nozzle carriage. This saves a lot of device. Operation is also easier because there is no need to move a nozzle carriage. There is no supply line for the engine of the jet car and for its control.

The tubes are all the same length. The nozzle bar is arranged on an already existing carrier and parallel to it, preferably it also has the length of the carrier. It is assumed that the field under consideration is already set up so that the carrier can be moved across the surface of the field transversely to its longitudinal direction. If this is not the case, the invention provides a holding device for receiving the nozzle bar, which has a moving device for displacing the nozzle bar parallel to the surface of the air cooler and a rotating device for rotating the nozzle bar about its longitudinal axis, and a fastening device for the arrangement on the air cooler. The latter parts replace those devices which already exist in a field equipped with a carrier.

Since the individual fields have different dimensions, it has proven to be advantageous to be able to extend the nozzle bar by means of extension pieces. The extension bar only makes the nozzle bar longer while maintaining its function. You choose a length that is slightly larger than the corresponding dimension of the field, so that the pipes are also safely cleaned at their ends.

The nozzle bar has an interior, it is connected to a connection end and the outlet nozzles. This interior is chosen so large that the water pressure applied to each individual outlet nozzle is as constant as possible, in any case the nozzle furthest from the connection end is still at a pressure is applied, which is a maximum of 30%, preferably a maximum of 10% less than the water pressure at the connection end.

In each case, a tube of the second layer is arranged on a gap between two tubes of the first layer, so that each tube of the first layer and a tube of the second layer located obliquely underneath are located in first inclined planes, which are parallel to one another, and in second inclined planes located that are parallel to each other. The amount of the angle at which the first inclined planes are to the surface is equal to the value of the angle at which the second inclined planes are to the surface. If a third layer is also present, its pipes are oriented again like the first layer and / or they are oriented such that the first and second inclined planes are continued.

If one looks in the longitudinal direction of the pipes in the longitudinal direction and selects two neighboring pipes in the first level and designates them with L and M, then the pipe N of the second layer adjacent to these two pipes lies on a gap in the middle between L and M. The three pipes L , M and E always lie on the corner points of an isosceles triangle. The two isosceles angles start from L and M and N is the tip of the isosceles triangle. The triangle side LN lies in the first inclined plane, the triangle side MN lies in the second inclined plane. This described geometry applies to all pipes, except for pipes on the edge. If the triangle LME is a right-angled triangle, the two inclined planes are each at an angle of 45 ° to the surface and the two types of inclined plane intersect at 90 °. If the triangle LME is an equilateral triangle, the two inclined planes each form an angle of 60 ° with the surface and the first and second inclined planes intersect at an angle of 60 °.

The nozzles typically have a jet angle of 15 °. For example, they are arranged at a distance of 10 cm. In this case, the individual nozzles must be arranged approx. 38 cm from the surface in order to ensure that the jets of neighboring nozzles just touch each other in the surface.

Figur 1

eine prinzipielle Darstellung einer Vorrichtung zur Reinigung eines Feldes, gesehen in Längsrichtung der Rohre,

Figur 2

eine Draufsicht auf ein Feld mit einem Träger und einer Reinigungsvorrichtung,

Figur 3

eine Draufsicht auf ein Teilstück eines Düsenbalkens, und

Figur 4

eine Draufsicht auf einen Düsenbalken und ein mit diesem verbundenen Verlängerungsstück.

An embodiment of the invention, which is not to be understood as limiting, is explained in more detail below and described with reference to the drawing. The drawing shows:

Figure 1

2 shows a basic illustration of a device for cleaning a field, seen in the longitudinal direction of the pipes,

Figure 2

a plan view of a field with a carrier and a cleaning device,

Figure 3

a plan view of a portion of a nozzle bar, and

Figure 4

a plan view of a nozzle bar and an extension piece connected to this.

Figure 1 shows a section of a field of an air cooler, the field has four layers, which are layered from top to bottom. The individual layers are each formed by tubes 20. All tubes 20 have the same length, are straight and identical. All tubes 20 run parallel to each other, at right angles to the drawing plane in the figure. The tubes 20 of a first, upper layer, which forms the surface of the air cooler, run in a first plane 22. The tubes 20 of a second layer underneath run in a second plane 24. There are also a third plane 26 and a fourth plane 28 intended. The distance between the centers of adjacent tubes 20 of each level is constant, it is s. The planes have the same distance t from each other. The distance t has the value for the case considered here $$\mathrm{t}=\mathrm{½s\surd }\mathrm{3rd}$$

If one looks at two adjacent tubes 20, for example of the first level 22, their centers are M and N, then the tube of the second level 24 closest to these two centers M and N lies on a gap or, in other words, between the first two tubes 20. The center of the considered Pipe of the second level 24 be L. The points M, N and L lie in the considered embodiment on the corner points of an equilateral triangle.

In general and applicable to every execution case, the center points lie on the corner points of an isosceles triangle, the same legs starting from M and N and each leading to L. The triangle side ML always runs in a first inclined plane 30, the triangle side NL in a second inclined plane 32. Since the above consideration applies to practically any triangular configurations of the tubes 20 that are picked out arbitrarily (except edge regions), there are always n tubes 20 on the same inclined plane, where n the number the layers or levels. However, this does not always apply in the marginal area. The first oblique plane 30 and the second oblique plane 32 intersect at an intersection angle. In the case of a right-angled, isosceles triangle, this is 90 °.

Again specifically to the embodiment according to Figure 1 . A nozzle bar 34 is shown diagonally above the pipes 20 shown. It consists of a tube that defines an interior 36. This is with a connection end 68 (see Figure 2 ) and a number of outlet nozzles 40 in communication. At the connection end 68, a hose 42 can be detachably connected, via which water is supplied at a pressure of, for example, 100-200 bar. This hose 42 is flexible. The water can only escape from the interior 36 via the outlet nozzles 40. These are identical in construction. They are arranged in a straight line. During operation, water emerges from them in a main jet direction 44. The main jet directions 44 of all nozzles 40 lie in one plane. The invention now provides that for practical use this plane is first aligned parallel to the first inclined plane 30 and in a further pass parallel to the second inclined plane 32. The inclined planes 30, 32 form sets of inclined planes 30, 32, a first inclined plane 30 and a second inclined plane 32 pass through each center point of a tube 20.

The nozzle 40 has a clear distance D from the first plane 22, which is assumed to be the surface of the field. In the exemplary embodiment shown, the distance D is chosen to be significantly smaller than in reality. This has been done to keep the presentation clear. In the exemplary embodiment shown, a conical water jet 46 emerges from the nozzle 40. The opening angle is about 14 °. If, in addition, a distance of adjacent nozzles 40 on the nozzle bar 34 of approximately 10 cm is selected, the distance which is approximately 3.5 times larger must be selected than shown.

In Figure 1 the edge jets 48 of the water jet 46 are shown. A large proportion of the water jet does not directly hit the tubes 20 of the top, first level 22, but also reaches the tubes 20 of the lower levels. When cleaning according to the orientation Figure 1 is completed, the nozzle bar 34 is pivoted by 60 ° and it is now irradiated along the second inclined plane 32. The arrangement is then a mirror image of that in Figure 1 shown representation.

In Figure 2 a section of a field is shown. Only the tubes 20 of the upper, first level 22 are shown in order to keep the drawing simple. In a known manner, the individual tubes 20 open at the top and bottom into head pieces 50. Rails 52 are arranged thereon, via which a carrier 54 can be moved in a controlled manner in the direction of the double arrow 56. The rails 52 form at least part of a fastening device for the carrier 54. A holding device 58 is arranged laterally on the carrier 54 and is composed of a lower part 60 and an upper part 62. The holding device 58 carries the nozzle bar 34. This is longer than the tubes 20, reaches into the area of the two head pieces 50. The nozzles 20, which are not shown in that they are directed downward, also extend into the region of the head pieces 50. This ensures that the pipes 20 are located below the nozzles 20 over their entire length.

In the upper part 62, the nozzle bar 34 is held so as to be pivotable about an axis 64, see rotary arrow. In the lower part 60, the nozzle bar 34 is rotatably held. The upper part 62 forms a rotating device. Specifically, the nozzle bar 34 consists of a primary nozzle bar and an extension piece 66, which is attached to the upper end of the primary nozzle bar. Several extensions can be installed one after the other. The nozzle bar 34 is adapted to the length of the tubes 20 by the extension pieces 66. Alternatively, nozzle bars 34 of different lengths can be provided, making it unnecessary, but still possible, to provide extensions.

The nozzle bar has a connection end 68. It is designed, for example, as a screw thread or in particular as a standard coupling for high-pressure water connections, all according to the prior art. A hose 70 for the HD feed line is connected to the connection end 68. The high pressure water is supplied via it, see arrow.

In practical operation, the rotating device 62 is first operated such that the nozzles 20 are aligned parallel to the first inclined plane 30 of the field. By moving the carrier 54 in at least one direction of the double arrow 56, all the tubes 20 of the field are then run over. The rotary device is then actuated such that the nozzles 20 are aligned parallel to the second inclined plane 32 of the field. Another run over by moving follows of the carrier 54 in at least one direction of the double arrow 56. During the movements, all the tubes 20 are run over at least once, often also several times.

The nozzle bar 34 is, for example, a metallic tube, in particular a round tube. At its end opposite the connection end 68, it has a connecting means, for example a thread, with which either an extension piece 66 or a head piece 70 cooperates. The head piece 50 closes the interior 36. If an extension piece 66 is used, a head piece 70 is also arranged at its free end. Other designs in which, for example, the nozzle bar is closed on one side are possible. In the Figures 3 and 4 the arrow indicates where water is being fed.

1. a) Bereitstellen eines Düsenbalkens 34, der eine große Anzahl von Aus-trittsdüsen 40 aufweist, die auf einer geraden Linie angeordnet sind und zu-einander parallele Hauptstrahlrichtungen 44 haben,
2. b) Anordnen des Düsenbalkens 34 an einem Träger 54 des Luftkühlers,
3. c) Ausrichten der Hauptstrahlrichtungen 44 der Austrittsdüsen 40 parallel zu einer ersten Schrägebene 30,
4. d) Einspeisen von Wasser unter Druck in den Düsenbalken 34, so das Wasser unter Druck aus den Austrittsdüsen 40 parallel zu der Schrägebene 30 austritt, und
5. e) Verschieben des Düsenbalkens 34 über die Oberfläche.

The method for cleaning an air cooler of a large industrial plant, wherein the air cooler has at least one field with at least two layers of tubes 20, these tubes 20 run in a straight line, the tubes 20 of all layers run parallel to one another, the tubes 20 being located under a first layer , second layer are each arranged on a gap between two tubes 20 of the first layer, so that each tube 20 of the first layer and an obliquely below tube 20 of the second layer are in inclined planes 30, 32, which are parallel to one another, with the following method steps :

1. a) providing a nozzle bar 34 which has a large number of outlet nozzles 40 which are arranged on a straight line and have main jet directions 44 which are parallel to one another,
2. b) arranging the nozzle bar 34 on a carrier 54 of the air cooler,
3. c) aligning the main jet directions 44 of the outlet nozzles 40 parallel to a first inclined plane 30,
4. d) feeding water under pressure into the nozzle bar 34 so that the water exits under pressure from the outlet nozzles 40 parallel to the inclined plane 30, and
5. e) moving the nozzle bar 34 over the surface.

Terms such as essentially, preferably and the like, and possibly information which is to be understood as imprecise, are to be understood such that a Deviation by plus minus 5%, preferably plus minus 2% and in particular plus minus one percent from the normal value is possible. The applicant reserves the right to combine any features and also sub-features from the claims and / or any features and also partial features from a set of the description in any manner with other features, sub-features or sub-features, even outside of the features of independent claims. The applicant further reserves the right to delete any features and also partial features.

In the different figures, parts that are equivalent in terms of their function are always provided with the same reference symbols, so that these are generally only described once.

The description preferably relates to pipes and the like, which are not arranged in edge areas of the field. For example, the last pipe of a level lacks a partner on one side, so that the description "set on a gap" applies more.

Reference symbol list

20th

pipe

22

1st level

24th

2nd level

26

3rd level

28

4th level

30th

1. Oblique plane

32

2. Oblique plane

34

Nozzle bar

36

inner space

40

Outlet nozzle, nozzle

42

tube

44

Main beam direction

46

Water jet

48

Edge jet

50

Headpiece

52

rail

54

carrier

56

Double arrow

58

Holding device

60

lower part

62

upper part, rotating device

64

axis

66

Extension piece

68

Connection end

70

Headpiece

M

Focus

N

Focus

L

Focus

D

distance

s

Distance between the centers of neighboring pipes

t

Distance between adjacent levels

Claims (8)

Method for cleaning an air cooler of a large industrial plant, the air cooler having at least one field with at least two layers of pipes (20), these pipes (20) run in a straight line, the pipes (20) of all layers run parallel to one another, the pipes (20 ) a first layer, which forms the surface of the air cooler, run in a first plane (22), the tubes (20) of an underlying second layer run in a second plane (24) which is parallel to the first plane (22) and in each case one tube of the second layer is arranged on a gap between two tubes (20) of the first layer, so that each tube (20) of the first layer and a tube (20) of the second layer located obliquely underneath are inclined (30, 32 ) that are parallel to each other with the following process steps: a) providing a nozzle bar (34) which has a large number of outlet nozzles (40) which are arranged on a straight line and have main jet directions (44) which are parallel to one another, b) arranging the nozzle bar (34) on a carrier (54) of the air cooler, if present, or on the air cooler itself, and enabling controlled movement of the nozzle bar (34) parallel to and above the surface of the air cooler, c) aligning the main jet directions (44) of the outlet nozzles (40) parallel to a first inclined plane (30), d) feeding water under pressure into the nozzle bar (34) so that the water exits under pressure from the outlet nozzles (40) parallel to the inclined plane (30), and e) moving the nozzle bar (34) over the surface. A method according to claim 1, characterized in that the following steps are carried out after step e): f) aligning the main jet directions (44) of the outlet nozzles (40) parallel to a second inclined plane (32) which runs at the same value of its angle to the surface but is different from the first inclined plane, and g) moving the nozzle bar (34) over the surface. A method according to claim 1 or 2, characterized in that the outlet nozzles (40) have an outlet angle of their outlet jets and are also each arranged at a distance from one another, and that the nozzle bar (34) is arranged at a distance D from the surface and this distance D is chosen so that at this distance D the exit jets of adjacent nozzles at least touch one another, preferably overlap somewhat. Device for cleaning an air cooler of a large industrial plant, the air cooler having at least one field with at least two layers of pipes (20), these pipes (20) run in a straight line, the pipes (20) of all layers run parallel to one another, the pipes (20 ) a first layer, which forms the surface of the air cooler, run in a first plane (22), the tubes (20) of an underlying second layer run in a second plane (24) which is parallel to the first plane (22) and a tube of the second layer is arranged on a gap between two tubes (20) of the first layer, so that each tube (20) of the first layer and a tube of the second layer located diagonally below are in inclined planes (30, 32), which are parallel to one another, the device has A) a nozzle bar (34), which has a large number of outlet nozzles (40), which are arranged on a straight line and have parallel main jet directions (44), and which has a connection end (68) with a supply line for pressurized water can be connected B) a holding device (58) for receiving the nozzle bar (34), which has a moving device for displacing the nozzle bar (34) parallel to the surface of the air cooler and a rotating device (62) for rotating the nozzle bar (34) about its longitudinal axis, and which has a fastening device for the arrangement on the air cooler. Apparatus according to claim 4, further characterized by at least one extension piece (66) for the nozzle bar (34), wherein the Extension piece (66) in the longitudinal direction of the nozzle bar (34) is tightly connected to the latter and has outlet nozzles (40) which are arranged parallel to the outlet nozzles (40) of the nozzle bar (34) and at the same distance as these. Apparatus according to claim 4 or 5, characterized in that the nozzle bar (34) has an interior (36) which is connected to the connection end (68) and the outlet nozzles (40), and that the pressure of the water in the interior (36 ) in the vicinity of the connection end (38, 68) is a maximum of 30%, preferably a maximum of 10% greater than the pressure of the water in the vicinity of a free end of the nozzle bar (34). Device according to one of claims 4-6, characterized in that the nozzle bar (34) has a head piece (70) that is arranged at its end region remote from the connection end (68) and preferably a coupling for a hold in the rotating device (62) having. Device according to one of claims 4-7, characterized in that the nozzle bar (34), possibly with at least one extension piece (66), has a length which is greater than the length of the tubes (20), in particular at least 10%, preferably is at least 20% longer.

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