Ship including a system for reducing vibrations originating from the hull and method of building the same

Abstract

The present invention relates to a ship (1), comprising at least one hull (20) defining a chamber (21) extending in a vertical direction across a ship deck (10); at least one chimney (30) mounted in the hull and comprising a plurality of concentrated mass components (31, 32, 33, 34) and a plurality of components (35; 36) with mass distributed along the length; a plurality of structures (51, 52, 53) supporting the plurality of components in the hull (20). The supporting structures comprise: a plurality of main platforms (51), each main platform defining a main support base located in the chamber (21) and connected to the wall of the hull (20) at the ship deck (10) through the intervention of a main elastic suspension (61); and a plurality of auxiliary platforms (52), each auxiliary platform being directly or indirectly supported by only one of the plurality of main platforms (51) and defining an auxiliary support base arranged at a different height relative to the main support base defined by the corresponding main platform (51).

Description

Technical Field

[0001] The subject of the invention is a vessel comprising a system for reducing vibrations originating from a hull and a method of building such a vessel.

[0002] In particular, the ship which is the subject of the invention is a cruise ship. Background Art

[0003] The flues E for the combustion fumes produced by the engines M of the ship N are arranged in one or more vertical chambers extending from the engine room S to the chimney F, passing through all decks P of the ship, such as Figure 1 As shown. Each chamber has a generally rectangular cross section and is delimited around its edges by a closed structure C suitable for separating said chamber from the rest of the ship. This closed structure C, whose technical name is "engine casing (or housing)" or "hull (or housing)", is structurally connected to the deck P of the ship. The hull C is an integral part of the ship's structure and performs important structural functions.

[0004] In a cruise ship, the hull is integrated into the center of the ship. Therefore, the hull is surrounded by the other spaces, rather than being a separate structure or appendage as in a cargo ship. Therefore, in a cruise ship, the hull walls are usually adjacent to the living areas inside the ship.

[0005] Typically, the vertical chamber is also used for the passage of other ducts, for example ventilation ducts V (in particular for ventilating engine rooms), steam lines, vent ducts, compressed air ducts and the like.

[0006] All components installed in the vertical chamber (from the flue E to the ventilation ducts) are supported in said chamber by means of horizontal support beams T fixed to the hull wall at each ship deck, forming a series of grid-like platforms.

[0007] In recent years, due to the need to comply with increasingly stringent environmental standards, flues have been equipped with flue gas treatment equipment comprising very heavy and bulky components.

[0008] Specific as Figure 2 and Figure 3 As shown, in addition to the flue gas duct line TE, the flue currently also includes the following components (listed in sequence starting from the engine room S): a system for controlling NOx emissions (SCR, selective catalytic reduction), an exhaust gas boiler EGB for generating steam, a system SCB for controlling SOx emissions (or "scrubber") and one or more silencers.

[0009] Systems for controlling NOx emissions

[0010] The new IMO Tier III regulations further restrict the emission limits in ECAs (Emission Control Areas). In this case, they aim to reduce NOx emissions by 80%. The most commonly used device for reducing NOx in the shipbuilding industry is a two-stage SCR (Selective Catalytic Reduction) system, which is positioned upstream of the exhaust gas boiler as the first element in the flue. In addition to being based on a chemical process, SCR uses gas passing through an extruded honeycomb catalyst. This catalyst constitutes a barrier to the free passage of the flue gases, thereby becoming an area where energy is transferred from the flue gases to the surrounding structure in the form of vibrations and sound.

[0011] Exhaust gas boiler

[0012] Some of the heat from the combustion gases is recovered in the tube bundle inside the exhaust gas boiler to produce steam. This tube bundle constitutes a real barrier to the gas flow, which is necessary for heat exchange but generates vibrations and noise. Energy is thus transferred to the supporting structure via the foundation of the exhaust gas boiler in the form of significant structure-borne noise. It is therefore necessary to limit this transfer using suitable elastic supports.

[0013] The SCR and exhaust gas boiler are the heaviest elements within the hull. As an approximation, taking into account the dimensions used, the weight of a single SCR / exhaust gas boiler may range from 3.2t for a vessel with a GRT of 10,900 to 24t for a vessel with a GRT of 134,000.

[0014] Muffler

[0015] In order to be able to perform their function, silencers must also work on the principle of pressure drops by exchange with surfaces made of absorbent material (resistive silencers) or on the principle of reflecting sound waves trapped in specially designed chambers (reactive silencers). These pressure drops are similar in magnitude to those in exhaust gas boilers, so these can also constitute preferred transmission points for structure-borne noise. Each silencer weighs between 1 t and 10 t, depending on its size.

[0016] Systems for controlling SOx emissions

[0017] In addition to the requirements to reduce NOx emitted into the air, new limits for SOx exhaust gas desulphurization are constantly being updated. To comply with the new regulations, ship owners are increasingly relying on treatment systems consisting of washing towers (called scrubbers). These scrubbers are also areas that transmit vibrations to the hull, although to a much lesser extent than the exhaust gas boiler and SCR, since the pressure drop caused by the flue gases is smaller and is therefore in fact similar to a pipe section of a duct. However, scrubbers have a significant impact on the stability of the ship, since they are positioned in the highest part of the hull and are much heavier than simple ducts. The average weight of a scrubber is about 20t.

[0018] As mentioned above, several components arranged in the shell transmit noise and vibration to the shell and thereby to the surrounding structures. Therefore, every structure in the shell connected to the deck is a potential carrier for transmitting noise radiated in the surrounding area of ​​the shell.

[0019] In particular, the chimney components transmit low-frequency vibrations generated by the ship's internal combustion engine to the hull. These vibrations are essentially composed of vibrations at the engine's fundamental rotation frequency and vibrations at the engine's ignition frequency.

[0020] In order to limit the transmission of noise and vibrations from the components inside the housing to the housing, elastic suspensions (consisting of rubber bodies or rubberized brackets, etc.) are currently provided at the points where these components (scrubbers, exhaust gas boilers, SCRs, pipelines, etc.) are attached to the supporting platforms inside the housing. These solutions are used for flue gas treatment equipment and through pipelines.

[0021] However, in some cases, the use of elastic suspensions does not satisfactorily reduce vibrations, at least in the vicinity of the hull. In particular, these elastic suspensions do not reduce low-frequency vibrations. Therefore, at least in cruise ships, the space adjacent to the hull (which is usually a valuable area because it is located in the center of the ship) is separated from the hull by the intervention of a buffer space used as, for example, a storage room and / or a cabinet.

[0022] However, the provision of said buffer spaces is not a completely satisfactory solution, since it not only does not always ensure effective vibration reduction, but also takes up useful space in valuable areas of the vessel. This problem is particularly true in vessels of average / small tonnage.

[0023] Therefore, in the ship industry, especially in the field of cruise ships, there is a need to further reduce the transmission of noise and vibration to the ship structure adjacent to the hull without the intervention of a buffer space. Summary of the invention

[0024] Therefore, the object of the present invention is to eliminate or at least reduce the drawbacks of the prior art by providing a vessel having a system for reducing vibrations originating from the hull, making it possible to further reduce the transmission of noise and vibrations to structures adjacent to the hull without the intervention of a buffer space.

[0025] Another object of the present invention is to provide a vessel having a system for reducing vibrations originating from the hull which can be produced at substantially the same production costs as conventional solutions and which is structurally easy to produce. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The technical features of the present invention according to the above-mentioned purpose can be clearly found in the content of the claims, and the advantages of the present invention will become more apparent through the following specific embodiments, wherein the specific embodiments are given with reference to the accompanying drawings, which illustrate one or more embodiments of the present invention only by way of non-limiting examples, in which:

[0027] Figure 1 is a cross-sectional view of the cruise ship corresponding to the shell to highlight the flue installed therein;

[0028] Figure 2 for Figure 1 Detailed drawing of the shell and flue only;

[0029] Figure 3 Shows Figure 2 , in which only the equipment of the flue is shown, and the relative pipelines are not shown;

[0030] Figure 4 is a cross-sectional view of a ship having a system for reducing vibrations originating from a hull according to an example of the present invention, the cross section corresponding to the hull;

[0031] Figure 5 for Figure 4 Detailed drawing of the housing only and the flue installed therein;

[0032] Figure 6 Shows Figure 5 , in which only the concentrated mass components of the flue are shown, and the distributed mass components are not shown;

[0033] Figure 7 for Figure 5 The housing shown is a plan view according to the section VII-VII shown therein;

[0034] Figure 8 , Fig. 9 , Fig.10 and Fig.11 They are three-dimensional diagrams of the first module, the second module, the third module, the fourth module and the fifth module, wherein: Figure 4 , Figure 5 and Figure 6 The flue in the shell shown is divided;

[0035] Fig.12 Shows Figure 5 , in which only the structure for supporting the concentrated mass component is shown;

[0036] Fig.13 A diagram showing a vibration isolator with one degree of freedom;

[0037] Fig.14 The trend of the frequency ratio f / f0 with respect to the transmissibility T is shown as a function of the value of the damping ratio ζ;

[0038] Fig.15 A diagram showing a two-stage vibration isolator; and

[0039] Fig.16 Schematic diagram of the operating range of certain types of passive suspensions depending on the type of decoupling device used.

[0040] The same elements or parts of elements in the embodiments described below will be denoted by the same reference numerals. DETAILED DESCRIPTION

[0041] The subject matter of the invention is a ship and a method for building such a ship, wherein the ship has a system for reducing vibrations originating from the hull.

[0042] In particular, the ship which is the subject of the invention may be a cruise ship.

[0043] With reference to the accompanying drawings, reference numeral 1 generally designates a vessel of the present invention.

[0044] According to Figure 4 In the general embodiment of the invention shown, the vessel 1 comprises:

[0045] -Hull 2;

[0046] - a plurality of decks 10 arranged inside the hull 2;

[0047] at least one engine casing 20 defining a chamber 21 extending vertically from an engine room 22 upwards across the plurality of decks 10 to a chimney 23; and

[0048] at least one flue 30 for the use of flue gases generated by one or more internal combustion engines 24 arranged in the above-mentioned engine room 22 .

[0049] In particular, the internal combustion engine 24 may be a diesel engine or a diesel / gas engine.

[0050] The flue 30 is installed in the shell 20 and includes a plurality of concentrated mass components 31, 32, 33, 34 and a plurality of components 35, 36 with mass distributed along the length.

[0051] A "lumped mass component" is a component of the flue 30 having a substantial mass (also relevant to the system in question), the mass of which is supported by one or more contact points on which a relative weight rests, but which is within a confined area.

[0052] In particular, the mass / volume ratio is equal to or greater than 100 kg / m 3 The components can be classified as concentrated mass components.

[0053] In particular, the multiple concentrated mass components of the flue 30 include:

[0054] - at least one SCR (Selective Catalytic Reduction) system 31, which is a catalytic system for controlling NOx emissions; and / or

[0055] - at least one exhaust gas boiler 32 for producing steam; and / or

[0056] - at least one flue gas scrubber 33, which is a system for controlling SOx emissions; and / or

[0057] - At least one silencer 34 .

[0058] like Figure 5 As shown, the flue 30 preferably includes: one or more SCR systems 31 ; one or more exhaust gas boilers 32 for generating steam; one or more flue gas scrubbers 33 ; and one or more silencers 34 .

[0059] As an approximation, the average mass / volume ratio of the SCR may be about 220 kg / m 3 The average mass / volume ratio of the exhaust gas boiler can be about 650 kg / m 3 The average mass / volume ratio of the flue gas scrubber can be about 130 kg / m 3 The average mass / volume ratio of the silencer can be between 100-220kg / m 3 between.

[0060] A “component with distributed mass along the length” is understood to be a component of the flue 30 of moderate mass (also in relation to the system in question) which has an extended longitudinal extension.

[0061] In particular, a pipe section of a pipe may be classified as a component whose mass is distributed along its length. More particularly, the mass / volume ratio is less than 50 kg / m 3The components can be classified as components whose mass is distributed along the length.

[0062] In particular, the component whose mass is distributed along its length is a duct section of the duct 35 of the flue 30, which fluidly connects the various concentrated mass components of the flue to each other, thereby forming the necessary fluid continuity from the engine exhaust to the chimney.

[0063] Specifically, the chamber 21 defined by the housing 20 may be a single chamber from the engine room 22 to the chimney 23. More complex embodiments may be provided. Figure 4 , Figure 5 and Figure 6 As shown, the chamber 21 may branch at the bottom into two initial sections 21 a and 21 b (for example, in order to be used in two separate engine rooms), which are connected upstream by a single upper section 21 c extending upwardly to the chimney 23 .

[0064] The housing 20 may contain two or more distinct flues which may remain separate until the chimney or may be reconnected at a common terminal section.

[0065] For ease of description, the following description will be made with reference to one flue, but it is not intended to be limited to the case of a single flue.

[0066] The vessel 1 may advantageously comprise one or more lines for the passage of working fluids, such as ventilation lines, air vent lines, lines for the passage of steam, and hydraulic lines.

[0067] Certain sections of the duct 36 of the one or more working fluid lines may advantageously be mounted within the housing 20. These sections of the duct 36 may be considered as additional components with respect to the distributed mass component 35 of the flue 20, the mass of which is distributed along the length.

[0068] Especially Figure 5 , Figure 6 and Fig.12 As shown, the ship 1 further comprises a plurality of structures 51 , 52 and 53 suitable for supporting the plurality of concentrated mass components 31 , 32 , 33 , 34 and the plurality of length-distributed mass components 35 , 36 located within the hull 20 .

[0069] According to the invention, the above-mentioned support structure comprises a plurality of main platforms 51 , each of which defines a main support base located inside the chamber 21 and connected to the wall of the hull 20 at the ship deck 10 through the intervention of main elastic suspensions 61 .

[0070] Each main platform 51 is preferably formed by a framework of beams that are structurally interconnected to form a grid-like structure, as shown in FIG. Figure 8 , Fig. 9 , Fig.10 and Fig.11 shown.

[0071] According to the present invention, the above-mentioned support structure also includes multiple auxiliary platforms 52, each auxiliary platform 52 is directly or indirectly supported by one of the main platforms 51, and defines auxiliary support bases located at different heights relative to the main support base defined by the corresponding main platform 51.

[0072] Specific as Figure 7 , Figure 8 , Fig. 9 , Fig.10 and Fig.11 As shown, each auxiliary platform 52 is preferably constructed from a framework of beams that are structurally interconnected to form a grid-like structure.

[0073] The main platform 51 and the auxiliary platform 52 may have the same peripheral shape as the shell cross section, for example, a rectangle. Other embodiments may also be provided in which the platforms 51 and 52 have a shape different from the shell cross section. The peripheral shape of the platforms is selected based on the requirements for the location of the various components of the flue, and so that the geometry of the platforms does not interfere with the walls of the shell.

[0074] According to the invention, at least one of said concentrated mass components 31 , 32 , 33 , 34 of the flue 30 is positioned on each main platform 51 .

[0075] Two or more of the concentrated mass components may be positioned on the main platform 51 .

[0076] The components consisting of the following components constitute the structural independent modules 50a, 50b, 50c, 50d, 50e:

[0077] - Main platform 51;

[0078] - at least one concentrated mass component 31, 32, 33, 34 respectively;

[0079] - one or more possible auxiliary platforms 52 supported by the main platform; and

[0080] One or more components 35 , 36 of distributed mass along the length, connected to said main platform 51 and / or to said one or more possible auxiliary platforms 52 .

[0081] Advantageously, the chimney 30 is thus divided into two or more structurally independent modules 50 , which are arranged one behind the other along the vertical extension of the casing 20 .

[0082] According to the embodiment shown in the drawings, three independent flues 30 are installed in the housing 20. Starting from the engine room, each flue 30 includes an SCR system 31, an exhaust gas boiler 32, a flue gas scrubber 33 and a silencer 34 in sequence, which are connected together by a pipe section of a pipe 35. In the example shown in the drawings, the three flues 30 share the same flue gas scrubber 33. The above components of the three flues 30 are divided into five modules 50a, 50b, 50c, 50d, and 50e that are independent of each other in structure. The first module 50a includes a scrubber 33 and three silencers 34; the second module 50b includes an exhaust gas boiler 32; the third module 50c includes an SCR system 31 and two exhaust gas boilers 32; the fourth module 50d and the fifth module 50e (arranged on two separate parts of the housing) both include an SCR system 31.

[0083] Preferably, at the top of the housing 20, near the chimney 23, each flue 30 comprises at least one fan (not shown in the drawings).

[0084] More specifically, the fans may be contained in a first module 50a, supported by one or more auxiliary top platforms, wherein the auxiliary top platforms support their weight on the main platform of the first module 50a by means of an interconnecting structure. Alternatively, as shown in the accompanying drawings, the fans may be arranged in another structurally independent module 50f (end or top module), which is used to close the housing at the top and is provided with its own main platform 51 (which is connected to the housing 20 by means of its own main elastic suspension 61) and one or more auxiliary platforms 52. In this case, the fans are considered as auxiliary or secondary concentrated mass components.

[0085] In particular, the modules 50a, 50b, 50c, 50d, 50e may extend in the vertical direction to an extent equal to the spacing between two or more ship decks. The modules 50a, 50b, 50c, 50d, 50e may have different vertical extensions. The vertical extension of a module is substantially determined by the size of the one or more concentrated mass components arranged in the module and the longitudinal extension of the pipe sections of the pipes arranged therein.

[0086] A module may contain components of a single flue (as is the case with module 50e in the drawings) or may contain components of two or more different flues passing through the same shell segment 20 (as is the case with modules 50a or 50d in the drawings).

[0087] According to the present invention, the dimensions of the above-mentioned main elastic suspension 61 of each main platform 51 are designed to reduce the transmission of low-frequency vibrations generated by the engine and transmitted by the flue 30 in the housing 20 from the corresponding module 50a, 50b, 50c, 50d, 50e to the housing 20. The above-mentioned main elastic suspension 61 reduces the above-mentioned low-frequency vibrations by utilizing the higher total mass of the corresponding module 50a, 50b, 50c, 50d, 50e.

[0088] Advantageously, dampening the vibrations reduces the annoying structure-borne noise generated by them. "Structure-borne noise" refers to noise transmitted through the structure of a vessel, generated by sources that cause the structure to vibrate.

[0089] Specifically, especially Figure 6 As shown, each module 50a, 50b, 50c, 50d, 50e is supported on a plurality of protrusions 25 corresponding to the respective main platforms 51, which protrude into the shell and are structurally integrated with the ship deck and / or integrated into the shell 20. The dimensions of all these protrusions 25 are designed to unload the entire weight of the entire module 50a, 50b, 50c, 50d, 50e onto the shell and / or the deck of the ship from which the protrusions extend. On each protrusion 25, one of the main elastic suspensions 61 is provided, which is thus located between the module 50a, 50b, 50c, 50d, 50e and each protrusion 25.

[0090] Compared with the technical solutions in the prior art, the present invention can achieve the following two results, which cooperate to reduce / cut the transmission of low-frequency and ultra-low-frequency vibrations from the flue to the shell:

[0091] - Fewer connection points between the supporting structure and the hull: the chimney is no longer connected to every deck of the ship, but only to the deck of the ship set at the height of the main platform; and

[0092] - The higher mass of the flue, and the mass of the supporting structures 51, 52, 53 distributed on several modules 50a, 50b, 50c, 50d, 50e are combined to define a higher mass (with greater inertia) to be utilized to increase the attenuation of low-frequency and ultra-low-frequency vibrations; this also makes it possible, in particular, to use an elastic suspension with high efficiency and low frequency as the main elastic suspension.

[0093] In other words, designing the chimney and the relative supporting structure as several structurally independent modules 50a-e makes it possible to utilize the higher mass involved in reducing the natural frequency f0 of the system as a single structurally independent module 50a, 50b, 50c, 50d, 50e, so as to ensure that the characteristic frequencies, fundamental frequencies and ignition frequencies caused by the operation of the engine fall into the maximum possible damping zone, thereby minimizing the vibrations transmitted to the ship structure.

[0094] Preferably, in order to be able to suspend a plurality of such systems, which are significant in mass, in view of the masses involved (i.e. structurally independent modules 50a, 50b, 50c, 50d, 50e each including equipment, pipelines, main and auxiliary platforms), the efficient, low-frequency main elastic suspensions used are those developed for large equipment such as main engines. These suspensions in fact have the required characteristics and, unlike those used in the prior art for suspending concentrated mass components, they are optimized to ensure a very low stiffness k, which results in a very low natural frequency of the elastic components (up to 4 / 5 Hz), which, combined with the mass m of the module, makes it possible to make the natural frequency f0 of the system very low and decoupled from the excitation frequencies (main and ignition frequencies), whereby the excitation frequencies will be effectively reduced.

[0095] Specifically, the low-frequency vibrations generated by the engine and transmitted through the flue 30 in the housing 20 include:

[0096] - vibrations at the fundamental rotational frequency of the engine, the fundamental rotational frequency being the frequency associated with the rotation of the drive shaft; and

[0097] - Vibrations at the engine firing frequency, which is the frequency at which the engine cylinders fire.

[0098] Preferably, the fundamental rotation frequency of the engine is between 7-30 Hz, and the ignition frequency of the engine is preferably between 40-150 Hz.

[0099] Preferably, the main elastic suspension 61 of each module 50a, 50b, 50c, 50d, 50e has a natural frequency lower than 7 Hz.

[0100] More specifically, each module 50a-e can be considered as a system with one degree of freedom, which will have a natural resonant frequency that depends on the stiffness k of the primary elastic suspension 61 and the mass m of the oscillator (suspended module), as follows:

[0101]

[0102] Among them, m is the mass of the suspension and k is the stiffness of the elastic suspension.

[0103] To illustrate this concept, it is useful to consider the transmissibility T, which represents the ratio between the force F transmitted to the foundation (the ship's structure / hull 20) and the force F0 (ie, the excitation force).

[0104] The specific case considered by the invention mainly concerns the transfer from the engine through the suspension points to the structure of the ship by means of the SCR, exhaust gas boiler, silencer and scrubber (which extract energy from the exhaust gas flow by interacting with it and discharge it).

[0105] According to the present invention, the mass m is composed of the entire module (centralized mass components and distributed mass components, main platform and auxiliary platform).

[0106] It is also known that the transmissibility can be expressed according to the following equation:

[0107]

[0108] Where, X = f / f0, f is the excitation frequency, and C is the damping factor.

[0109] Therefore, the amplitude of a system with one degree of freedom depends on the mass m, the stiffness k, and the damping factor.

[0110] From the T equation given above, we can see that:

[0111] - When X approaches 0, the transmissibility T approaches 1; thus, the ratio is controlled by the stiffness k;

[0112] - As X approaches values ​​greater than 1, the transmissibility T approaches zero; this ratio is controlled by the mass m.

[0113] Fig.14 The trend of the frequency ratio f / f0 with respect to the transmissibility T is shown as a function of the value of the damping ratio ζ, where the damping ratio ζ corresponds to the C / Cc ratio, Cc being the critical damping coefficient. When ζ<0, the transient response of the system is cyclic; when ζ>=1, the response of the system is no longer cyclic. When ζ=0, the system has no damping. The case of ζ=0 is derived from the equation of motion of an oscillator with one degree of freedom my"+Cy'+ky=F(t), from which the natural undamped frequency f0 of a system with one degree of freedom is obtained, F(t)=C=0. Typical ζ values ​​for rubber are 0.05-0.1, while typical ζ values ​​for steel are 0.005-0.01.

[0114] Now refer to Fig.14 , from which it can be seen that for values ​​below resonance (f / f0=1), there is neither isolation nor amplification; near resonance (f / f0=1), there is amplification, and above 1.4X, the presence of the separation element significantly increases the isolation. Therefore, when the frequency f0 of the system is at least 1.4 times lower than the excitation frequency, the presence of elasticity is effective.

[0115] For this reason, it is preferred to have a primary elastic suspension with a very low natural frequency (about 5 Hz, k low) to maximize the isolation effect, taking into account the frequencies involved above (the minimum of which is around 7 Hz). Furthermore, as represented by the transmissibility equation T, in addition to resonance, the response is also controlled by mass; therefore, increasing the mass makes it possible to reduce f0, thereby increasing the f / f0 ratio, which is beneficial to the isolation system, thereby reducing the transmission of vibrations to the structure of the ship.

[0116] Thanks to the invention, the transmission of low-frequency and very low-frequency vibrations from the chimney to the hull and structures of the ship adjacent to said hull can be significantly attenuated, without disturbing the hull and these structures adjacent to the hull.

[0117] In particular, it is no longer necessary to arrange a buffer space around the housing. In this way, the volume around the housing is freed up (in the solutions in the prior art, the volume around the housing cannot be used as a valuable location due to the intensity of the vibrations originating from the housing).

[0118] Furthermore, the technical solution of the invention can be produced at substantially similar costs to conventional solutions. In particular, no intervention is required in the structure of the vessel, but only the structures within the hull need to be reconfigured. As will be emphasized below, the division of these structures into structurally independent modules 50a-e makes it possible to apply prefabrication methods that reduce assembly and installation costs.

[0119] As mentioned above, the ship 1 may include one or more pipelines for the passage of the working fluid. Some pipe sections of the pipes 36 for the one or more pipelines for the passage of the working fluid may be installed in the shell 20. These pipe sections of the pipes 36 are regarded as additional components with distributed mass along the length relative to the distributed mass components of the flue 20. Some pipe sections of the pipes 36 for the one or more pipelines for the passage of the working fluid may be installed in the shell 20.

[0120] Advantageously, some pipe sections of the pipes 36 of the one or more pipelines installed in the housing 20 for the working fluid to pass through can be connected to the above-mentioned support structures 51, 52, 53 as additional mass distributed along the length. In this case, each structural independent module 50a, 50b, 50c, 50d, 50e can include one or more pipe sections of the pipes 36.

[0121] Preferably, line sections of pipes 36 belonging to ventilation lines, exhaust lines, steam channel lines and hydraulic lines are connected to supporting structures 51 , 52 , 53 , whereas pipes of fire protection lines are attached directly to the wall of housing 20 for safety reasons.

[0122] Preferably, the pipe sections of the pipe 35 for the passage of exhaust gases and the pipe sections of the pipe 36 of one or more lines for the passage of working fluids arranged in the first module, if provided, are fluidically connected to the pipe sections of the pipes of the corresponding lines arranged in the second module adjacent to the first module by means of flexible connections 37. In this way, the fluid continuity of the various lines can be ensured without the need to structurally fasten the different modules 50a-e to each other.

[0123] Preferably, as shown in the accompanying drawings, in particular Fig.12As shown, the above-mentioned support structure includes a plurality of structural interconnections 53 between the main platform 51 of a module and each auxiliary platform 52 of the same module 50a, 50b, 50c, 50d, 50e.

[0124] In particular, these structural interconnects 53 (which are preferably vertical) can directly connect the auxiliary platform 52 to the main platform 51 (as shown in module 50b) or can indirectly connect the auxiliary platform 52 to the main platform 51 through at least one intermediate auxiliary platform (for example, as shown in modules 50a and 50c).

[0125] Advantageously, if Figure 8-Figure 11 As shown, the support structures 51, 52, 53 in each module 50a, 50b, 50c, 50d, 50e form a structurally integrated support frame, in particular a cage-like support frame, in which the concentrated mass components and components with distributed mass along the length belonging to the module are arranged.

[0126] The auxiliary platform 52 of one module may be disposed above and / or below the corresponding main platform 51 .

[0127] Preferably, the auxiliary platform 52 of a module may be arranged above the main platform 51, as provided in modules 50a, 50b and 50c. In this case, the structural interconnects 53 work mainly under compression. However, embodiments may be provided in which one or more auxiliary platforms 52 may be arranged below the main platform 51, as provided in modules 50d and 50e. In this case, some structural interconnects 53 may also work under traction.

[0128] Preferably, each auxiliary platform 52 of one module is composed of a structure that is thinner and lighter than the structure constituting the corresponding main platform 51 .

[0129] More specifically, the structural dimensions of the main platform 51 of a module are designed to support the entire weight of the corresponding entire module 50a, 50b, 50c, 50d, 50e. The auxiliary platform 52 performs an auxiliary structural function and is therefore basically suitable for:

[0130] - ensure support for the pipeline (lighter; component with mass distributed along its length); and

[0131] - To ensure access to the device for maintenance purposes, it is possible to travel along the entire vertical extension of the housing.

[0132] For these reasons, the structure forming the auxiliary platform 52 can be reduced to a thinner and lighter structure compared to the technical solutions in the prior art, which on the contrary provide a platform with a structure similar to the deck of a ship at each deck of the ship within the shell.

[0133] This preferred configuration provides a large weight saving margin with respect to the supporting structure in the hull. For example, in a ship with 20 decks, assuming that the chimney is divided into 4 modules, this means that the weight of about 16 decks can be saved. In general, the reduction in the total weight of the structure in the hull is estimated to be of the order of at least 40%.

[0134] Preferably, the sum of the masses of the corresponding main platform 51 and at least one concentrated mass component 31, 32, 33, 34 (or two or more concentrated mass components (if any)) in a module 50a, 50b, 50c, 50d, 50e constitutes more than 50% of the mass of the entire module, and even more preferably constitutes 75% to 90% of the mass of the entire module.

[0135] Preferably, each module 50a, 50b, 50c, 50d, 50e is configured so that its center of gravity is located in the vicinity of the corresponding main platform 51. In other words, each module is configured so that this center of gravity is placed as close as possible to the plane passing through the main elastic suspension 61. This further promotes the stability of said module 50a, 50b, 50c, 50d, 50e inside the shell. In this way, it is therefore possible to increase the vertical extension of a module without having to use stabilizing elements connecting the module to the shell at different heights relative to the main platform in order to damp any vibrations caused on said module by the movement of the ship.

[0136] Advantageously, as shown in the figures, in the case of module 50c, the main platform 51 may extend in several planes in order to position several concentrated mass components at different heights within the module. In other words, the main platform 51 may include portions that are not coplanar with each other.

[0137] Preferably, each module 50a, 50b, 50c, 50d and 50e is structurally independent from the other modules and is mechanically connected to the housing 20 only through the above-mentioned primary elastic suspension 61.

[0138] Preferably, the main elastic suspensions 61 of each main platform 51 are distributed symmetrically with respect to the center of gravity of the corresponding module.

[0139] According to a preferred embodiment, one or more of the concentrated mass components 31, 32, 33, 34 and / or one or more of the length-distributed mass components 35, 36 can be connected to the support structure 51, 52, 53 by means of one or more auxiliary elastic suspensions 62. Preferably, in particular, Figure 5 and Figure 6 As shown, the concentrated mass components 31 , 32 , 33 , 34 are connected to the support structures 51 , 52 , 53 via one or more of the auxiliary elastic suspensions 62 , while the length-distributed mass components 35 , 36 are directly connected to the support structures 51 , 52 , 53 .

[0140] Operationally, the action of the auxiliary resilient suspension 62 as described above is added to that of the main resilient suspension to further reduce the transmission of vibrations and noise from the flue 30 to the housing and the structure of the ship adjacent to the housing. Thus, a double suspension system is formed, which can be considered similar to a two-stage insulator, as Fig.15 schematically shown in

[0141] Preferably, a double suspension is used when the efficiency of a single suspension is not suitable or when it is necessary to attenuate not only very low frequencies but also another frequency. This is the case for diesel engines, for which both the main frequency and the ignition frequency are taken into account.

[0142] More specifically, as Fig.15 schematically shown, a double suspension with two degrees of freedom actually has two natural frequencies, involving two masses m1 and m2, where m1 is an intermediate mass in the present invention composed of the sum of the mass of the main platform plus the mass of the auxiliary platform and all the pipes (distributed mass) rigidly connected thereto. This mass m1 must be as large as possible compared to the mass m2 of each suspended concentrated mass component; if necessary, it can reach 70% of it.

[0143] In this specific case, there will thus be two frequencies related to the system, a lower f1 and a higher fb, which are combinations of the resonant frequencies f1 and f0, where:

[0144] f1 = the resonant frequency of the mass m1, where the mass m2 is considered fixed;

[0145] f0 = the resonant frequency of a system with one degree of freedom having the mass m2, without considering the mass m1.

[0146] Combining these two frequencies to describe the system enables the calculation of:

[0147] f1, which will always be < f1 or f0;

[0148] fb, which will always be > f1 or f0,

[0149] at double the frequency relative to the higher frequency fb.

[0150] Preferably, the above-mentioned main resilient suspension 61 and (if any) the above-mentioned auxiliary resilient suspension 62 are composed of passive resilient suspensions. Specifically, these passive resilient suspensions include decoupling components, which are preferably made of a body made of an elastic material, especially rubber or silicone, metal springs, elastic components including a metal matrix, and / or air springs. Fig.16Schematically illustrated are the operating ranges of certain types of passive suspensions depending on the type of decoupling device used.

[0151] According to a particular embodiment, the primary elastic suspension 61 and the auxiliary elastic suspension 62 (if present) may be constituted by:

[0152] - a semi-active elastic suspension consisting of a mass damper; or

[0153] -Active elastic suspension.

[0154] Specifically, "active elastic suspension" refers to an active system for isolating vibrations (AVC), which together with the suspension contains a feedback loop consisting of sensors (for example, piezoelectric accelerometers or geophones), controllers and actuators. The signals acquired by the extremely sensitive vibration sensors are analyzed by electronic circuits, which drive electric actuators, which instantly generate reaction forces that compensate for the vibrations. This active anti-vibration system does not resonate and amplify vibrations at any frequency.

[0155] Advantageously, embodiments may be provided in which a combination of passive, semi-active and active elastic suspensions may be used in the same module.

[0156] According to a preferred embodiment of the present invention, each module 50a, 50b, 50c, 50d, 50e is a self-supporting structure, preferably prefabricated off the ship. In operation, each module 50a, 50b, 50c, 50d, 50e is completely formed under the ship to then be installed in the shell from above.

[0157] The method of building the ship 1 according to the present invention will now be described.

[0158] For simplicity of description, the entire description of the vessel 1 will not be repeated, but reference will be made to the preceding description.

[0159] The method for building the ship 1 of the present invention comprises at least the following steps:

[0160] a) constructing a hull 2 ​​having a plurality of decks 10 arranged inside the hull and at least one hull 20 defining a chamber 21 extending vertically from at least one engine room 22 upwards across the plurality of decks 10 to a chimney 23;

[0161] -b) at least one flue 30 for smoke generated by one or more internal combustion engines 24 arranged in the at least one engine room 22 is installed in the shell 20, wherein the flue 30 includes a plurality of concentrated mass components 31, 32, 33, 34 and a plurality of components 35, 36 with mass distributed along the length, and the concentrated mass components and the components with mass distributed along the length are supported in the shell by a plurality of structures 51, 52, 53.

[0162] According to the present invention, the above-mentioned support structures 51, 52, 53 include:

[0163] - a plurality of main platforms 51 , each defining a main support base located inside said chamber 21 and connected to the wall of the hull 20 at the ship's deck 10 through the intervention of main elastic suspensions 61 ; and

[0164] a plurality of auxiliary platforms 52 , each of which is supported directly or indirectly by only one of the main platforms 51 and defines an auxiliary support base arranged at a different height relative to the main support base defined by the corresponding main platform 51 .

[0165] In the above-mentioned installation step, step b), the components of the support structures 51, 52, 53 and the flues 31, 32, 33, 34 and 35 and 36 are brought together to form structurally independent modules 50a, 50b, 50c, 50d, 50e.

[0166] Each structurally independent module includes a main platform 51, at least one concentrated mass component 31, 32, 33, 34 positioned on the main platform, one or more possible auxiliary platforms 52 supported by the main platform, and one or more mass components 35, 36 connected to the main platform 51 and / or the one or more possible auxiliary platforms 52 and distributed along the length.

[0167] The dimensions of the main elastic suspension 61 of each main platform 51 are designed to utilize the total mass of the corresponding module 50a, 50b, 50c, 50d, 50e to reduce the transmission of low-frequency vibrations generated by the engine and transmitted through the flue 30 in the casing 20 from the corresponding module 50a, 50b, 50c, 50d, 50e to the casing 20.

[0168] According to a preferred embodiment of the present invention, each module 50a, 50b, 50c, 50d, 50e is a self-supporting structure, preferably prefabricated off-board. In operation, each module 50a, 50b, 50c, 50d, 50e is formed completely outside the ship to then be installed in the shell from above.

[0169] The present invention achieves the advantages presented throughout the specification.

[0170] Thanks to the invention, the transmission of low-frequency and very low-frequency vibrations from the chimney to the hull and structures of the ship adjacent to said hull can also be significantly reduced, without disturbing the hull and structures adjacent to it.

[0171] In particular, it is no longer necessary to arrange a buffer space around the housing. This frees up volume around the housing which, in prior art solutions, could not be used as valuable locations (e.g. public areas, restaurants, etc.) due to the intensity of the vibrations originating from the housing and the resulting structure-borne noise.

[0172] Furthermore, the technical solution of the present invention can be implemented at substantially similar costs to conventional technical solutions. Specifically, no intervention in the structure of the ship is required, but only the structure within the hull needs to be reconfigured.

[0173] Advantageously, thanks to the invention, and in particular thanks to the division of the chimney in the supporting structure and the housing into several modules, the chimney can be designed with greater freedom, being less constrained by the ship's deck.

[0174] According to a preferred embodiment, configuring the structure within the hull as a structurally independent module makes it possible to reduce the weight on board and lower the height of the center of gravity, which is beneficial to the stability of the ship.

[0175] Dividing the structure within the housing into structurally independent modules allows the application of prefabrication methods that reduce assembly and installation costs.

[0176] The invention conceived in this way therefore achieves the set objects.

[0177] Of course, when implemented in practice, the invention may also present embodiments and configurations different from those described above, without thereby departing from the scope of the present invention.

[0178] Moreover, all the details may be replaced by technically equivalent elements and, according to requirements, any dimensions, shapes and materials may be used.

Claims

1. Ship (1), including: -hull(2); - a plurality of decks (10) arranged in the hull (2); - at least one housing (20) defining a chamber (21) extending vertically from at least one engine room (22) across the plurality of decks (10) to a chimney (23); - at least one flue (30) for the flue gases generated by one or more internal combustion engines (24) located in said at least one engine room (22), said flue (30) being mounted in said housing (20) and comprising a plurality of components (31, 32, 33, 34) with concentrated mass and a plurality of components (35; 36) with mass distributed along the length; - a plurality of support structures (51, 52, 53) suitable for supporting the plurality of components (31, 32, 33, 34) with concentrated mass and the plurality of components (35; 36) with distributed mass along the length within the housing (20); Characterized in that the supporting structure comprises: - a plurality of main platforms (51), each main platform (51) defining a main support base located inside said chamber (21) and connected to the wall of the hull (20) at the ship deck (10) through the intervention of main elastic suspensions (61); and - a plurality of auxiliary platforms (52), each auxiliary platform (52) being supported directly or indirectly by only one of the plurality of main platforms (51) and defining an auxiliary support base disposed at a different height relative to a main support base defined by the respective main platform (51); wherein at least one of the concentrated mass components (31, 32, 33, 34) is positioned on each main platform (51); Furthermore, the components consisting of a main platform (51), at least one corresponding concentrated mass component (31, 32, 33, 34), one or more possible auxiliary platforms (52) supported by the main platform, and one or more components (35; 36) connected to the main platform (51) and / or one or more possible auxiliary platforms (52) and having a mass distributed along the length constitute a structural independent module (50a, 50b, 50c, 50d, 50e); Furthermore, the dimensions of the main elastic suspension (61) of each main platform (51) are designed to utilize the total mass of the corresponding module (50a, 50b, 50c, 50d, 50e) to reduce the transmission of low-frequency vibrations generated by the engine and transmitted through the flue (30) in the shell (20) from the corresponding module (50a, 50b, 50c, 50d, 50e) to the shell (20).

2. The vessel according to claim 1, wherein: The vibration includes vibration at a basic rotation frequency of the engine and vibration at an ignition frequency of the engine, wherein the basic rotation frequency of the engine is 7-30 Hz, and the ignition frequency of the engine is 40-150 Hz.

3. A ship according to claim 1 or 2, wherein: At least one module (50a, 50c) comprises two or more concentrated mass components (31, 32, 33, 34); and the two or more concentrated mass components are positioned on a main platform (51) of the module.

4. The ship according to claim 1 or 2, wherein: The main platform (51) of the module (50c) includes a non-coplanar portion.

5. The ship according to claim 1 or 2, wherein: The plurality of concentrated mass components of the flue include at least one SCR device (31).

6. The ship according to claim 1 or 2, wherein: The plurality of concentrated mass components of the flue include at least one exhaust gas boiler (32).

7. The ship according to claim 1 or 2, wherein: The plurality of concentrated mass components of the flue include at least one scrubber (33).

8. The ship according to claim 1 or 2, wherein: The plurality of concentrated mass components of the flue include at least one silencer (34).

9. The ship according to claim 1 or 2, wherein: The plurality of mass-distributed lengthwise components of the flue gas duct include pipe sections of a pipe (35) for conveying exhaust gases.

10. A vessel according to claim 1 or 2, comprising one or more pipelines for the passage of a working fluid, wherein: The pipe sections of one or more pipelines (36) for the working fluid to pass through are installed in the shell (20) and are connected to the support structure (51, 52, 53) as additional mass components distributed along the length, wherein each module (50a, 50b, 50c, 50d, 50e) includes one or more pipe sections of the pipe (36).

11. The ship according to claim 1 or 2, wherein: A pipe section of a pipe (35) arranged in a first module through which exhaust gas passes is fluidically connected to a pipe section of a corresponding line arranged in a second module arranged adjacent to the first module via a flexible connection (37).

12. The vessel of claim 10, wherein: A pipe section of a pipe (35) for exhaust gas to pass through arranged in a first module and a pipe section of one or more pipes (36) of a pipeline for working fluid to pass through are fluidically connected to pipe sections of corresponding pipelines arranged in a second module arranged adjacent to the first module via a flexible connector (37).

13. The vessel according to claim 1 or 2, wherein: The main elastic suspension (61) of each main platform (51) is symmetrically distributed relative to the center of gravity of the corresponding module (50a, 50b, 50c, 50d, 50e).

14. The vessel according to claim 1 or 2, wherein: The support structure comprises a plurality of structural interconnects (53) between a main platform (51) of a module and each auxiliary platform (52) of the same module (50a, 50b, 50c, 50d, 50e), wherein the structural interconnects (53) are vertical and connect the auxiliary platforms (52) directly to the main platform (51) or indirectly to the main platform (51) via at least one intermediate auxiliary platform.

15. The vessel according to claim 1 or 2, wherein: The auxiliary platform (52) of the module is arranged above and / or below the corresponding main platform (51).

16. The vessel according to claim 1 or 2, wherein: Each auxiliary platform (52) of the module is composed of a structure that is thinner and lighter than the structure constituting the corresponding main platform (51).

17. The vessel according to claim 1 or 2, wherein: In the modules (50a, 50b, 50c, 50d, 50e), the sum of the mass of the corresponding main platform (51) and the mass of the at least one concentrated mass component (31, 32, 33, 34) accounts for more than 50% of the mass of the entire module (50a, 50b, 50c, 50d, 50e).

18. The vessel of claim 16, wherein: The sum of the mass of the main platform (51) and the mass of the at least one concentrated mass component (31, 32, 33, 34) accounts for 75%-90% of the mass of the entire module (50a, 50b, 50c, 50d, 50e).

19. The vessel according to claim 1 or 2, wherein: The center of gravity of the module is located near the corresponding main platform (51).

20. The vessel according to claim 1 or 2, wherein: One or more of the concentrated mass components (31, 32, 33, 34) and / or one or more of the length-distributed mass components (35; 36) are connected to the support structure (51, 52, 53) via one or more auxiliary elastic suspensions (62).

21. The vessel according to claim 1 or 2, wherein: The main elastic suspension (61) is composed of a passive elastic suspension, which includes a decoupling component made of a body of elastic material.

22. The vessel of claim 20, wherein: The main elastic suspension (61) and the auxiliary elastic suspension (62) are composed of a passive elastic suspension, and the passive elastic suspension includes a decoupling component, which is made of a body of elastic material.

23. The vessel of claim 21, wherein: The body of elastic material is rubber or silicone, a metal spring, an elastic component with a metal matrix, and / or an air spring.

24. The vessel of claim 20, wherein: The main elastic suspension (61) is composed of a semi-active elastic suspension.

25. The vessel of claim 20, wherein: The main elastic suspension (61) and the auxiliary elastic suspension (62) are composed of a semi-active elastic suspension.

26. The vessel of claim 20, wherein: The main elastic suspension (61) is composed of an active elastic suspension.

27. The vessel of claim 20, wherein: The main elastic suspension (61) and the auxiliary elastic suspension (62) are composed of an active elastic suspension.

28. The vessel of claim 1 or 2, wherein: Each module (50a, 50b, 50c, 50d, 50e) is structurally independent of the other modules and is mechanically connected to the housing (20) only through the primary elastic suspension (61).

29. The vessel of claim 1 or 2, wherein: Each module (50a, 50b, 50c, 50d, 50e) is a self-supporting structure.

30. The vessel of claim 29, wherein: The self-supporting structure is prefabricated off-board.

31. A method for building a ship (1), comprising the following steps: - (a) constructing a vessel (2) having a plurality of decks (10) and at least one hull (20), wherein: The plurality of decks (10) are arranged in the hull (2), and the at least one shell (20) defines a chamber (21) extending from at least one engine room (22) in a vertical direction across the plurality of decks (10) to a chimney (23); (b) installing at least one flue (30) in the housing (20) for flue gases generated by one or more internal combustion engines (24) arranged in the at least one engine room (22), wherein the flue (30) comprises a plurality of concentrated mass components (31, 32, 33, 34) and a plurality of components (35; 36) with distributed mass along the length, the concentrated mass components and the components with distributed mass along the length being supported in the housing by means of a plurality of support structures (51, 52, 53); Characterized in that the support structure (51, 52, 53) comprises: - a plurality of main platforms (51), each main platform (51) defining a main support base located inside said chamber (21) and connected to the wall of the hull (20) at the ship deck (10) through the intervention of main elastic suspensions (61); and - a plurality of auxiliary platforms (52), each auxiliary platform (52) being supported directly or indirectly by only one of the plurality of main platforms (51) and defining an auxiliary support base disposed at a different height relative to a main support base defined by the respective main platform (51); Furthermore, in the step (b), the supporting structure (51, 52, 53) and the components (31, 32, 33, 34; 35; 36) of the flue are gathered together to form a structurally independent module (50a, 50b, 50c, 50d, 50e); Each structural independent module comprises a main platform (51), at least one concentrated mass component (31, 32, 33, 34) located on the main platform, one or more possible auxiliary platforms (52) supported by the main platform, and one or more mass components (35; 36) connected to the main platform (51) and / or the one or more possible auxiliary platforms (52) and distributed along the length; The dimensions of the main elastic suspension (61) of each main platform (51) are designed to utilize the total mass of the modules (50a, 50b, 50c, 50d, 50e) to reduce the transmission of low-frequency vibrations generated by the engine and transmitted through the flue (30) in the shell (20) from the modules (50a, 50b, 50c, 50d, 50e) to the shell (20).

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