AU2005200630A1

AU2005200630A1 - An underwater exhaust device

Info

Publication number: AU2005200630A1
Application number: AU2005200630A
Authority: AU
Inventors: Florent Longer
Original assignee: Alstom SA
Current assignee: Chantiers de lAtlantique SA
Priority date: 2004-02-19
Filing date: 2005-02-11
Publication date: 2005-09-08
Anticipated expiration: 2025-02-11
Also published as: ES2309689T3; AU2005200630B2; ATE400496T1; FR2866625A1; DK1566333T3; EP1566333A1; EP1566333B1; FR2866625B1; DE602005007946D1

Abstract

The device has an exhaust case (5) connected to a gas exhaust system via an exhaust pipe (4). The case is placed at the level of an exhaust outlet (7) that is situated on a hull of a ship and placed below water-line. The case is partially closed by a deflector (6) having width equal to two-third of the width of the outlet, and providing smooth profile to the hull.

Description

AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: Name of Applicant: Alstom Actual Inventor(s): Florent Longer Address for Service and Correspondence: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: AN UNDERWATER EXHAUST DEVICE Our Ref: 738381 POF Code: 375552/353683 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): -1- 6o06q AN UNDERWATER EXHAUST DEVICE The present invention relates to ships and more particularly to exhausts for such ships.

Presently, two types of exhaust exist: above-water and underwater. These types can be used on their own or in combination.

Above-water exhausts suffer from the drawbacks of being noisy, of giving off unpleasant odors, and of forming plumes of smoke that are unattractive in appearance and easy to see.

Underwater exhausts operate only at high speeds (generally at speeds greater than 9 knots), they are placed close to the waterline and have an external deflector or "scoop" portion for preventing water from entering the exhaust and for protecting the engines from the back pressure exerted by the water. Although such a system is easy to implement, it is very sensitive to movements of the ship and to wave motion, because there is a risk of water entering the engines. The position of the exhaust close to the waterline gives rise to a risk of it being blocked with ice, and of the external pipe being damaged by flotsam or simply by quaysides. The odors are not entirely eliminated because of the small extent to which the gases disperse the water. In addition, the movement of the ship and the wave motion can cause the exhaust to come out of the water, and the fumes are then discharged directly into the air.

An object of the present invention is to propose an underwater exhaust device that is simple, that operates at low speeds, and that discharges only a small amount of fumes into the air in the vicinity of the ship.

An underwater exhaust device of the invention is constituted by an exhaust box connected to the exhaust gas network via an exhaust pipe, said box is disposed at an exhaust outlet situated in the hull of a ship, and said box is equipped with a deflector situated tangentially to said hull. The tangential deflector imparts a smooth profile to the hull of the ship, which makes it possible to go over to underwater mode at low speeds, and avoids risks of collision with flotsam.

According to a particular characteristic, the deflector is in the shape of an upside-down scoop. At low speeds, the substantially convex shape of the back of the scoop accelerates the flow inside the exhaust and facilitates removal of water, while the concave shape of the front of the scoop separates the streams of water from the hull and generates a ventilation zone aft of the profile. Under steady-state conditions, the profile guarantees that a zone of suction exists inside the exhaust pipe that is sufficient to discharge the gases.

In an advantageous configuration, the deflector has a horizontal width equivalent to two-thirds of the horizontal width of the exhaust outlet. This size is good for facilitating removal of the gases without giving rise to water intake into the exhaust box.

In an advantageous configuration, the exhaust pipe is horizontal.

According to a particular characteristic, the exhaust outlet is placed below the waterline. The very deep position of the exhaust outlet makes it possible to reduce external noise and discharges into the atmosphere, and to remove both the risk of discharging into the air in the event of movements of the ship or of wave motion, and also the risk of being iced over.

In a particular configuration, the exhaust outlet is situated more than 50 centimeters (cm) below the water line.

According to another characteristic, the exhaust pipe forms an angle of in the range 300 to 400 relative to the hull of the ship. Such horizontal inclination of the exhaust pipe relative to the deflector makes it possible to optimize the flows.

The invention will be better understood on reading the following description given merely by way of example and with reference to the accompanying drawings, in which: Figure 1 is a section view of the ship; Figure 2 is a plan view of the exhaust of the invention; and Figures 3 and 4 are plan views of the exhaust as closed and as open.

The ship 1 is provided with an exhaust 2 disposed under the waterline 3 at a certain distance from the surface (cf. Figure 1).

The exhaust 2 comprises an exhaust pipe 4 connected to the exhaust gas network 8 and to a box 5 disposed inside the ship at the exhaust outlet 7 and not projecting out from the hull 10 of the ship 1 (cf.

Figure The pipe 4 and the box 5 form an angle a relative to the hull 10. The angle a is measured from the forward portion 10a of the hull 10, and it lies substantially in the range 300 to 400.

As shown in Figure 2, the box 5 is closed in part by a deflector 6 fixed to the side of the box 5 at the forward portion 10a. The deflector 6 extends towards the bow of the ship 1 so that, when the ship is moving, water intake is as small as possible.

The deflector 6 is in the shape of a scoop whose concave portion 60 extends in line with the forward portion 10a of the hull 10 and is directed outwards from the ship i. The convex portion 61 is placed inside the hull 10. The two faces 60 and 61 of the deflector 6 converge going towards the stern of the ship i, so that the forward face 62 of the deflector is wider than its after portion 63.

Operation of the device is described below with reference to Figures 3 and 4.

As can be seen in Figure 3, if F is the direction in which the water is moving relative to the hull 10, under transient conditions, i.e. while the ship 1 is gathering speed and so long as said speed remains less than knots, the box 5 is filled with water, the exhaust gas network 8 then being in above-water mode. The deflector 6 facilitates removal of the water from the exhaust box via its portion 61. The profile 60 separates the streams of water from the hull in the exhaust zone and generates a ventilation zone aft of the deflector 6.

Once the speed has reached 5 knots, the exhaust network 2 goes over to underwater mode by opening a valve (not shown) disposed upstream, and the gases exit via the pipe 4 and the box 5 in which suction is sufficient to receive the exhaust gases. The profile 61 directs the gases towards the stern of the ship 1 and the portion deflects the streams of water so that the two flows are almost tangential when they come into contact with each other, thereby also facilitating flow and limiting drag.

Claims

2. An exhaust device according to claim 1, C characterized in that the deflector is in the shape of an upside-down scoop.
3. An exhaust device according to any preceding claim, characterized in that the deflector has a horizontal width equivalent to two-thirds of the horizontal width of the exhaust outlet
4. An exhaust device according to any preceding claim, characterized in that the exhaust pipe is horizontal. An exhaust device according to any preceding claim, characterized in that the exhaust outlet is placed below the waterline
6. An exhaust device according to any preceding claim, characterized in that the exhaust outlet is situated more than 50 centimeters (cm) below the water line (3)
7. An exhaust device according to any preceding claim, characterized in that the exhaust forms an angle of in the range 300 to 400 relative to the hull (10) of the ship (1) DATED: 11 February 2005 PHILLIPS ORMONDE FITZPATRICK Attorneys for: ALSTOM