The invention relates to a vessel's exhaust pipe arrangement according to the preamble of Claim 1 , comprising a set of exhaust pipes or similar which are supported on the vessel's hull.

Ship machinery such as main and auxiliary engines, waste incinerators and the like burners and boilers generate exhaust gases or other waste gases. These are usually conveyed into a separate chimney within which there may be several individual exhaust pipes or similar exhaust ducts from said sources. In this context, all of these are referred to as exhaust pipes. The intention is to place the upper ends of the exhaust pipes high enough to have the exhaust gases carried away by the flow of air around the vessel. The level of height between the turbulent boundary layer and so- called undisturbed air flow shall be determined by empirical assessment or wind- tunnel tests. If possible, exhaust pipes should extend above this level. On passenger ships and particularly on large cruise ships, it is important to minimise the harmful effects of exhaust gases, such as soot and smell, on outer decks occupied by passengers. Exhaust pipes typically extend significantly above the actual deck superstructure and the highest decks occupied by passengers. As the ship's size increases, the exhaust of flue gases must be located higher above sea level in order to achieve the objective described above.

In many sea routes, sounds, channels and harbour areas, the overhead clearance of ships is limited due to bridges, power lines, aerial cableways or similar structures. In most cases, particularly on passenger ships, the exhaust pipe is the highest point of the ship, which means that overhead clearance imposes a limit on increasing the size and height of the ship.

Because the operation of ship machinery cannot be interrupted i.a. due to reasons relating to safety, arrangements such as hinged or removable exhaust pipes are unacceptable. The most common solution is to take the overhead clearance limits into account and design the exhaust pipes in accordance with a specified maximum height. A common consequence of this is that the vessel becomes smaller and/or lower than would otherwise be preferable. A compromise is also often made with regard to the requirement of extending the exhaust pipes through the boundary layer mentioned above. In this case, one must accept that smoke will be deposited on deck areas in a disturbing manner.

The conveyance of exhaust gases above said turbulent boundary layer can be facilitated by various means. One way is to increase the gas flow rate in the exhaust pipe by throttling the exhaust gas flow; however, this impairs engine operation. An air flow supporting the flow of exhaust gas may also be arranged, for example using various kinds of air deflectors or by conveying ventilation exhaust air concurrently with exhaust gases. The effects of these means are limited and are usually in use already.

The conveyance of exhaust gases under the water is implemented mainly on warships; however, this brings many disadvantages to engine technology because thereby the so called exhaust back-pressure increases.

A one-off operation of disassembling and reassembling the chimney and/or the exhaust pipes contained within it requires the machinery and equipment producing exhaust gases to be stopped, which is troublesome and probably impossible in practice due to reasons such as safety.

A chimney or exhaust pipe that can be turned over with a hinged mechanism requires a lot of space and a massive turnover mechanism. Also in this case, the machinery and equipment producing exhaust gases would have to be stopped, which is probably impossible in practice due to reasons such as safety. One must also take the scale into account, as the exhaust pipes of a large passenger ship are correspondingly large and heavy.

The purpose of the invention is to provide a chimney solution for a ship or the like water-craft that will minimise the problems of prior art described above. The particular purpose of the invention is to provide a chimney solution suitable for large ships that allows the ship's overhead clearance requirement to be reduced quickly and easily according to the situation, with no need to stop the ship's machinery and equipment. The objectives will be achieved in the way presented in more detail in Claim 1 and in the other claims.

According to the basic idea of the invention, exhaust pipes are mounted on a common subframe to form a group that is moved mechanically in the direction parallel to the exhaust pipes, making the exhaust pipes mounted on the subframe slide within each other. According to the invention, each exhaust pipe or similar comprises a separate lower part that is rigidly supported on the vessel's hull and connected to a source of exhaust gas, and an upper part that is arranged in a sliding manner in relation to the lower part, most preferably partially over the lower part. The exhaust pipes or similar are arranged into an exhaust pipe group, with the upper parts of the exhaust pipes or similar supported on a separate exhaust pipe group body part that is fitted with transmission means to move the upper parts of the exhaust pipes or similar in relation to the lower parts.

The invention allows the height of the exhaust and waste gas duct assembly and the ship's overhead clearance to be adjusted without interrupting the gas flows while the machinery and equipment is in operation. The arrangement does not require much additional space, and its advantages also include the quickness and ease of changing the height, inconspicuousness particularly to passengers, as well as the safety of operations compared to prior art solutions.

In a preferred practical embodiment, the exhaust pipe group comprises a set of exhaust pipes with the upper parts supported on each other in pairs, and these exhaust pipe pairs are arranged in line. In this case, the body part of the exhaust pipe group is preferably arranged between the exhaust pipes in the exhaust pipe pairs. The body part includes a support frame mounted on the vessel's hull and a subframe movably supported on it, which in turn supports the upper parts of the exhaust pipes or similar. This creates a movable entity that is stable and compact in terms of structural design. The transmission means preferably comprise a gear rack supported on the subframe of the exhaust pipe group, with arrangements for transmitting force thereto in order to move it in the longitudinal direction of the pipes.

The exhaust pipes in the exhaust pipe group are arranged at an oblique angle in relation to the vessel's hull. Correspondingly, the body part of the exhaust pipe group is mainly rhomboid-shaped parallelogram. The solution is preferable particularly with regard to air drag.

In a preferred practical embodiment, a guide sleeve with slide rails is arranged in the lower part of the exhaust pipe for the purpose of supporting the lower part on the upper part. The slide rails in the guide sleeve are of a material having low coefficients of friction and thermal expansion, such as bearing bronze. With regard to potential wear, it is preferred that the guide sleeve is replaceable.

With regard to safety, it is preferred that the lower part of the exhaust pipe is thermally insulated.

The lower and upper parts of the exhaust pipe are preferably manufactured of acid- proof steel.

At the lower end of the upper part of the exhaust pipe, a water gutter or similar and at least one outlet hole can be arranged for collecting water. Furthermore, at the lower end of the upper part of the exhaust pipe, a flange or similar can be arranged to create a substantially gas-tight connection with a collar in the lower part when the upper part of the exhaust pipe is in its extreme upper position.

In the following, the invention will be described by way of example with reference to the enclosed schematical drawings, in which - Figure 1 illustrates a general principal diagram of the vessel exhaust pipe arrangement according to the invention,

- Figure 2a illustrates an exhaust pipe arrangement according to the invention that corresponds to the section Il - Il in Figure 1 , - Figure 2b illustrates the embodiment of Figure 2a with the exhaust pipe arrangement in the lowered position,

- Figure 3a illustrates section Ilia - IHa in Figure 2a,

- Figure 3b illustrates section 1Mb - HIb in Figure 2b, - Figure 4 illustrates a partial enlargement of Figure 1 at point IV,

- Figure 5 illustrates a partial enlargement of Figure 1 at point V,

- Figure 6 illustrates a section of Figure 1 at point Vl,

- Figure 7 illustrates section VII - VII in Figure 6,

- Figure 8 illustrates section VIII - VIII in Figure 3a, and - Figure 9 illustrates the partial enlargement IX-IX of Figure 3a.

In the drawings, exhaust pipes 1 to 6 are arranged into an exhaust pipe group. Each exhaust pipe has two parts so that the upper parts 1a to 6a of the exhaust pipes are arranged over the lower parts 1b to 6b in a telescope-like manner and are movable in relation to the lower parts. This allows the height of the exhaust pipes to be changed as necessary. The lower parts 1b to 6b of the exhaust pipes are attached to the hull 11 of the vessel and are connected to onboard sources of exhaust gas or similar waste gas in a way known from prior art (not shown).

The exhaust pipe group consisting of exhaust pipes 1 to 6 is supported on a separate body part 7 so that the upper parts 1 a to 6a of the exhaust pipes are supported on a subframe 7a belonging to the body part 7 using supports 1c and 1d etc., and the subframe 7a is movably supported on a support frame 7b attached to the vessel's hull 11. As is evident from Figures 2a, 2b, 3a and 3b, the body part 7 may also include an additional frame-type body part 7c to provide sufficient support to the exhaust pipe group in all situations, taking into account its weight, wind conditions etc.

The subframe 7a is fitted with a gear rack 8 at both ends, the gear rack 8 having a transmission connection with a pinion 9 driven by a suitable motor 10. This allows the subframe 7a to be moved in relation to the support frame 7b, which also provides movement of the upper parts 1a to 6a of the chimneys in relation to the lower parts 1 b to 6b. This is illustrated in Figures 2a and 2b, as well as Figures 3a and 3b. Naturally, the movements of both ends of the subframe 7a and the operation of the motors must be mutually synchronised in order to make the movement simultaneous and as smooth as possible. Because the movable entity consisting of the upper parts 1a to 6a of the exhaust pipe group and the subframe 7a can be quite heavy in practice, its upper position can be secured with separate locking elements as necessary, such as mechanically operated stud bolts or similar (not shown in detail).

As is evident from the figures, the support frame 7b can preferably be trough-shaped so that the subframe 7a moves into it when the height of the exhaust pipe group is reduced. It is also evident from the figures that the subframe 7a includes a set of reinforcement elements that can also be located triangularly crosswise to the structure (cf. Figures 2a and 2b) so that the subframe forms a sufficiently rigid support structure in terms of structural design.

For the purpose of moving the subframe 7a, the support frame 7b has guide elements 12 with suitable sliding surfaces as seen in Figures 8 and 9.

Correspondingly, the lower part of the exhaust pipe may have a guide sleeve (6e in Figure 6) to support it on the upper part of the exhaust pipe. The guide sleeve is preferably made of bearing bronze, and its attachment can be arranged so that it is replaceable. The actual exhaust pipes can preferably be acid-proof steel, which is well-suited for preventing soot buildup also when cold. Sealing of the exhaust pipe can be arranged through sufficient overlap of the upper and lower parts, choice of materials and appropriate clearances.

On the other hand, the guide sleeve (6e) can be fitted with slide rails 13 as shown in Figure 7. In this case, the so-called ejector effect may be utilised to prevent exhaust gas leaks; the effect draws fresh air into the chimney at the joint. In order to convey any water away from the exhaust pipe, a water gutter or similar and at least one outlet pipe can be arranged at the lower end of the upper part (not shown in detail). The lower part of the exhaust pipe can also be fitted with thermal insulation 14 as shown in Figure 6. This way, even though the exhaust gases are hot, the surface of the lower part of the exhaust pipe stays cooler.

As is evident from Figures 2a and 2b, the exhaust pipes can also be of different sizes depending on the sources and the volume flow of exhaust gases or, more extensively, waste gases that are to be exhausted. The embodiment shown in the figures where exhaust pipes are arranged into an exhaust pipe group in pairs is advantageous particularly with regard to space usage because it can be arranged in the longitudinal direction of the vessel, and the body part of the exhaust pipe group can be located between the pairs of exhaust pipes. Such an exhaust pipe group can be arranged in the longitudinal direction of the vessel symmetrically on both sides. Also, as illustrated in the figures, the exhaust pipe group can be inclined so that the body part forms a rhomboid-shaped parallelogram. This is a preferred solution particularly in terms of wind drag, but naturally the exhaust pipes can also extend straight up from the hull of the vessel.

The invention is not limited to the presented embodiments but several variations can be conceived within the scope of the associated claims.