US2646764A - Ship's funnel with smoke-directing provisions - Google Patents

Description

' July 28, 195:.

E. F; J. LASCROUX 2,646,764

' SHIPS FUNNEL WITH SMOKE-DIRECTING PROVISIONS 3 Sheets-Sheet 1 Filed Jan. 24, 1951 Arty y 2 1953 E. F; J. LASCROUX 2,646,764

SHIPS FUNNEL WITH SMOKE-DIRECTING PROVISIONS I 3 Sheets-Sheet 2 Filed Jan. 24, 1951 Fig.3

Arr

y 1953 E. F; J. LASCROUX 2,646,764

SHIPS FUNNEL WITH SMOKE-DIRECTING PROVISIONS n Filed Jan. 24, 1951 5 Sheets-Sheet 5 fimm WM MW Patented July 28, 1953 SHIPS FUNNEL WITH SMOKE-DIRECTING PROVISIONS Emile Frdric Joseph Lascroux, Le Soupicou, Presquile de Giens, France Application January 24, 1951, Serial No. 207,628 In France February 2, 1950 14 Claims.

The present invention relates to the evacuation' of smokes on board ships.

Said evacuation of smokes is normally ensured by a funnel.

Formerly, a ship's funnel was constituted by the pipe provided for the evacuation of the smoke from the boiler, the height of the pipe depending on the draught to be obtained.

Nowadays, with the use of a forced draught, the draught no longer plays any part in determining the dimensions of the smoke stack, so that whatever the type of the ship (steamer or diesel engines, for instance), the function of the funnel is purely and simply to evacuate the smokes, whether originating from the boilers or from the engines, far enough into the atmosphere so that it does not annoy the crew or the passengers by falling back on to the decks.

Present funnels, generally, consist of a vertical cylindrical casing with a circular or elliptical cross section, containing, without touching them, the evacuation pipe or pipes for the smokes. The base of this cylinder is set into the upper deck and its upper part opens directly into the atmosphere.

With an arrangement of this type, it is found that upon issuing from the funnel, the smokes escape from the horizontal draught caused by the relative wind and has a tendency to fall back on the deck, at the rear of the funnel. This fact can be explained as follows:

The relative wind directed perpendicular to the generatrices of the funnel casing results in an air flow around the cylinder that varies in velocity from the top to the bottom and from the front to the rear of said casing;

At the base of the funnel, this air flow is conditioned:

In front by the outer structures: such as forecastle, wheel house, boats;

At the rear, by structures such as roofs, deck drops and numerous air funnels, particularly those used for the supply of cool air.

All said structures cause, at the base of the funnel a zone of turbulence, the depth of which is irregular and which, in the absence ofany funnel is a characteristic of the ship; it is a kind of aero-dynamical wake, wherein the funnel is located. If said funnel is high enough, the flow of relative Wind, above a certain level, is that which corresponds to the horizontal cross section of the funnel: it is a function of the Reynolds index, and, in most cases it is both eddying and oscillating.

At the top of the funnel, the casing usual 1y ends in a sharp edge; the pipes which are used for evacuating the smokes and which are housed inside this casing, open under said edge and a little below a platform secured a little distance down said casing and serving as a roof for preventing rain water from entering said casing. The top of said casing thus constitutes a sort of cup shaped recess particularly suitable for the formation of a turbulence, so that, upon their issuing directly from the evacuation pipes, the smoke does not have a sufiicient speed, it is affected by this turbulence, and becomes turbulent. This drawback is still increased when the smoke passes over the rear of the envelope, which, due to its sharp edge, creates a rotational transition layer.

Now the speed of the smoke is appreciably reduced when it issues from the evacuation pipes since it passes from said pipes into an indefinite space, which causes a speed drop; the residual speed of the smoke then becomes easily capable of being affected by the field in which it has to move.

If said field were made up only of horizontal lines of flow of the relative wind, the trajectory of the smoke particles would be a more or less flattened parabola, depending on the ratio of the mutual speeds of the wind and smoke, but if, upon their emerging, they are compelled to go through a turbulent zone, a few particles, especially on the periphery, are necessarily carried away in the eddying wake behind the funnel and necessarily join the turbulence zone at the base of said funnel.

To avoid this flowing back of the smoke onto the deck, the speed of the smoke is generally given as high a value as possible with respect to that of the relative wind. In present practice, the speed of the smoke before it emerges into the atmosphere, reaches a maximum of twice that of the'relative wind, but, as soon as it comes out, this speed is almost always lower than the latter.

Thus, leaving aside turbulence, it is found that the profile of the trail of smoke which issues from a funnel is limited, in front, by an extremely flat parabola and, at the rear, by a straight line from the top of the funnel, so that if it is desired that the latter be located inside a zone free of all turbulence, the funnel must be givena very great height.

However, due to the turbulence caused by the upper cup shaped portion of the funnel and the sharp edge of its casing experience shows that even very high funnels do not always avoid a flowing back of the smoke onto the deck.

The present invention has for its object a funnel for ships which is improved in order to obviate the above mentioned drawbacks in an absolute manner.

The invention has more particularly for its object a ship funnel in which, on the one hand, the assembly of the smoke pipes is surrounded, over a certain length and substantially from the open upper ends of said pipes, with a streamlined envelope, the upper end of which is connected to a convex upper closing dome or cap, through which said pipes protrude slightly, and, on the other hand, two side screens, of a generally longitudinal direction, provide, on both sides of said envelope, two substantially longitudinal passage- Ways open at their front and rear ends, for canalising the outside air, at least one deflecting element being arranged in each passageway to give an upward direction to the air stream going through said passageway from the front to the rear or inversely.

Experience shows that, owing to the two ascending air streams, thus formed without any loss of speed and which originate on both sides of a middle longitudinal zone in which arise smoke to be evacuated, said smoke is not blown back towards the rear on to the deck of the ship, but escapes in a concentrated trail, substantially vertical at first, then gradually curving towards the rear to end in a substantially horizontal direction, sufficiently distant from the ships deck, however, so that said deck is no longer reached by the smoke.

Other features will appear from the following description.

In the appended drawing, given merely by way of example:

Fig. l is a vertical longitudinal section, along line l-l of Fig. 2 of an improved funnel according to the invention;

Fig. 2 is a semi-plane and semi-sectional View along line 22 of Fig. 1;

Fig. 3 is a transverse section along line 33 of Fig. 2;

Fig. 4 is a view in elevation of the front face of the smoke stack;

Fig. 5 is a similar view of the rear face;

Figs. 6 and 7 are schematic views showing two other embodiments of deflecting elements adapted to be arranged in the above mentioned longitudinal passageways.

Fig. 8 is a transverse vertical semi-section along line &8 of Fig. 9, of a modified funnel;

Fig. 9 is a longitudinal vertical section along line 9-9 of Fig. 8;

Fig. 10 is a view, in elevation, of a modification in which each side screen is provided with two apertures with adjustable vanes.

According to the embodiment shown in Figs. 1 to 5, the funnel according to the invention is arranged above the top deck I of the ship, just aft of the front cabin, of which (Figs. 1 and 4) the roof is shown at 2, the vertical, longitudinal walls at 3, and the rear wall at 5 all the walls being secured to the deck I by angle irons 5.

In the deck I is provided an oblong aperture 8 (Figs. 1 and 2) having a generally elliptical and more or less oval shape. Underneath this aperture, vertical walls I and 8 (Fig. 1) form, inside the ship, the vertical shaft which leads to the engine or boiler room; access may be to this shaft through the usual skylight 9, preferably with glazed portholes l0 (Figs. 1 and 2).

On the edge of aperture 6 is secured, by means of an angle iron II, the outer casing l2 of the funnel, constituting the base of the funnel, the front portion of said casing being cut out to accommodate the front-cabin. At its top, this outer casing I2 is capped by a plane and horizontal platform [3; this platform comprises, however, a front inclined plane Hi (Figs. 1, 2, 4) and preferably two rear inclined planes forming a dihedral angle 5 with a longitudinal edge l5. This platform I3 is provided, symmetrically to the longitudinal vertical plane XX with an aperture ll (Fig. 3), the contour of which is parallel to that of angle iron it visible on all its periphery on Fig. 2.

The various pipes, such as those l9, l9a from the boilers or main engines, 26 from the auxiliary boilers, 21 from the electro-generator groups, pipes for the evacuation of smokes or harmful gases etc., have their axes disposed on or about the above mentioned longitudinal plane XX. Their diameters should not exceed the width of the cover or cap. If the volume of the smoke or harmful gases to be evacuated leads to too large a diameter, for the corresponding pipes, said volume should be distributed into several evacuation pipes (such as 19, 19a) These various pipes are surrounded with a vertical downwardly flared envelope 22, secured by means of the angle iron 18 on the platform l3 to the edge of the aperture ll. The envelope 22 is of such a shape that all the horizontal cross sections of said envelope are streamlined and as narrow as possible. The ratio of the maximum width to the length of the casing 22 is at most equal to and this maximum width is at a distance from the front end equal to about of the total length. Finally, this length is substantially equal to twice the height of the envelope. The upper edge 23 of this envelope 22 is connected directly to a cap 24, also of a streamlined shape, the front of which protrudes at 25. The body of the envelope is connected thereto through a concave parabolic surface 26. It will be understood that the nose thus formed and this concave surface tend to direct laterally against the wall of the envelope 22 the air lines of flow which impinge on the front of said envelope.

On each side of the envelope 22, the base casing 52 of the funnel is extended and streamlined so as to constitute two side screens 2? which terminate with sharp edges at the front at 28 and at the rear at 29 (Figs. 2, 4, 5), leaving between them a vertical aperture the height of which is that of the inner envelope 22 and the width of which is larger adjacent to the front part of said envelope 22 than at the rear.

Each screen 21 is extended towards the front and towards the rear by a vertical metal sheet 30 or 3|, with rounded edges 32 or 33, secured to the casing i2, so as to form, with the latter, at each end, a vertical groove (see Figs. l, 5), serving to canalize, upwards along the casing and towards the side passageways arranged between the envelope 22 and screens 2'7, the mass of air which impinges on the base of the funnel, for example above the front-cabin (Fig. 4).

The horizontal cross section of the screens 21, at their base, is that of the casing l2, itself, while the upper edge 35 is substantially parallel to the base section 23 of the cap 24. This edge to, which is substantially horizontal, is extended by a small deflector 35 upwardly inclined towards the inside at an angle of about 30 (Fig. 4), the width 'of which is tapering from front to rear (see Fig. 2).

In the longitudinal passageway left free between the envelope 22 and each side screen 21, are placed two inclined planes 38 and 39 connected along an upper edge 49 which is approximately at the mid-length in the passageway, and un derneath the plane of the base 23 of the cap 24. These two planes 38, 39 downwardly, inclined towards the plane XX form together an angle a (Fig. 1) at most equal to 90. The rear plane 39 begins substantially at the rear of the passageway, the front plane 38 ending approximately adjacent the point of maximum width of the inner envelope 22. These planes take upthe whole free space between this inner envelope and each one of the sidescreens 21, and, at their bases, they are connected to a horizontal wall 4| also connecting the envelope 22 and the corresponding side screen 21. This wall 4|, located above the base platform 53, forms with it a kind of nozzle through which the middle portion of the passageway communicates with the rear.

The assembly of the two planes 38, 39, and of their base 4!, constitutes a deflecting element of a generally triangular shape placed in a passageway through which passes an air stream, horizontal at its origin, and this assembly'will condition the air flow around the cap 24.

The shape of each screen 2'! and the dimensions of the deflecting element are such that from the front to rear, the transverse section of each passageway first decreases, very approximately up to a point opposite the edge 48, then increases.

If the number of smoke evacuation pipes makes it necessary to give the cap 24 a'great length (case of Figs. 1 and 2) it will be preferably provided, as shown with, an additional inclined plane 42 between the front ramp 38 and the beginning of the passageway, so as to better canalize upwards the air entering said passageway. This plane may conveniently have a helical surface (Fig. 1)

Aperture 42a preferably grated at it, are provided in the platform l3,'in each one of the passageways.

Finally, on the outside, to each screen 211s secured, for instance slightly rear of the widest point of the funnel, a vertical vane 44 (Figs. 2, 4) normal to said screen.

The operation of the described assembly is as follows:

In an ordinary funnel, the mass of air which reaches the funnel at the relative wind speed moves around the sides of said funnel and its top is swept by a horizontal stream, so that the stream lines of the air flow which surrounds the funnel are horizontal everywhere.

On the contrary, in the described arrangement, an important portion of the mass of air which impinges on the funnel is compelled to flow away through the side passageways, theamount of air entering these passageways is increased due to the presence of flared arrangements provided at the ends of these passageways-and forming flared air intake channels (nose .23 and concave surface 25 of the'cap 24, cut off corner of the platform l3, deflecting walls3il, 3i).

In each passageway, the air is compelled to move around the triangular obstacle 38,39, 4|, both at top and bottom, not counting the front deflecting surface 42, which, if it is flttecLal ready ensures an upward diverting of the air stream.

In any case, the air. which passes atth'e bot.-

tom, underneath the wall 4|, has the effect of blowing the wake existing at the rear of the funnel in the vicinity of platform l3. On the other hand, the air which passes at the top moves over the edge 49 of the obstacle and this in the direction imparted to it by the plane 38 and with a speed increased by the very shape of the passageway.

The cap 24 is thus surrounded with a mass of air at an accelerated and ascending speed so that the smoke, upon issuing from the evacuation pipes, combines its own vertical speed with that surrounding them and the resultant direction of the issued smoke is markedly closer to the vertical.

For the device to be really efiicient, however, it must be effective not only with a relative head wind, but also for the most usual azimuths, i. e. from +30 to 30 from the plane XX. Now the very elongated funnels which are in favour at present offer a very large section and the wake resulting therefrom is very important. This wake is very efficiently obviated by the small vertical deflectors 44, normal to the screens 21. 'Experience shows that each one of these deflectors 44 perturbs the wake which, without, it would be very severe when the wind strikes the funnel at a large angle to the plane XX on the side opposite to that where the considered deflector is located. It will be noted further, that whatever may be the direction of the relative wind, the two passageways are always subjected to a more or less intense flow in one or the other direction, so that under the triangularv obstacle (38, 39, 4|) there is always a horizontal stream. The result is that the apertures 42a provided in the platform l3 serve not only as access holes for entering above said platform 13 but also for sucking out the vitiated warm air ascending from the stoke hold or the engine room, and which accumulates inside the base casing 12.

Of course, if it is desired to use this type of ventilation for a particular area of the bottom of the ship, the air to be evacuated may be canalized up to the apertures 42a by means of suitable pipes, and the speed of flow may be increased if these pipes are heated by the heat from the smoke evacuating pipes.

The deflecting elements placed in the passageway may be built otherwise than in the above described example.

Thus the inclined planes may have a longitudinal section concave in front, at 45 (Fig. 6) and convex at the rear at 46 and the base 4'iof the obstacle, instead of being plane, may be convex downwards. In such a case, the rear of the base platform is raised upwards at as.

Another modification, which, in fact, is only an extension of the above and which is represented in Fig. 7 consists in giving the obstacle 591) the section of a curved aircraft wing.

According to the example of embodiment shown in Figs. 8, 9 in each one of the two longitudinalpassageways provided above the platform [3 between each one of the two longitudinal screens 21 and the envelope 22 surmounted by the cap 24 through which emerge the evacuation pipes for the smoke and other harmful gases, are also arranged an auxiliary deflector 42 and a main deflector which comprises two inclined walls 38a, and 39a connected at their bottoms with the platform l3. These walls are not directly connected at the top as in the previous example, but each one of them may be respectively extended by vanes 49 and 49a mounted so as to oscillate respectively about transverse axle 50 and 50a. Each axle is trunnioned in the Walls 22 and 21 and is respectively extended by levers 5i and 52. Each one of said levers terminates respectively in eyelets 53 and 54, through which pass, respectively, pins 55 and 5S, capable of engaging respectivel in one of a series of holes 57 and 58 provided in the wall 22, on a circular arc concentrical with the axis of oscillation of the corresponding vane.

It is thus possible to adjust very easily the angular position of the vane as or tea either against the corresponding wall 38a or tea (position of vane 4a), or more or less distant from the wall (position of the vane Sta) which makes it possible to adjust the orifice which gives a communication of the passageway provided between the walls 22 and 27 with the space under the deflector and which is in communication, through at least one grated aperture 21 with the engine or boiler room and consequently allows the ventilation of this room under the suction effect caused in the direction of the arrows f by the air which circulates in the above mentioned passageway in the direction of the arrows P.

The auxiliary deflector G2 is of one of the above described types.

Another modification of the funnel according to the invention is shown in Fig. 10, in which each side screen 59 has a cylindrical shape with vertical generatrices and is provided with two apertures so and iii, respectively, towards the front and towards the rear. The lower edge 62 of the rear aperture is above the rear face 3% of the deflector. Each one of these apertures is provided with a vane 63, 834, controlled for instance underneath the platform 53 by a lever 65, 66.

These side apertures 5B, 5!, allow additional air intakes which may be useful with winds having a large inclination to the longitudinal vertical plane of symmetry of the funnel.

Whatever may be the shape of the deflector, it is its presence in the passageway which conditions the flow and it is the passageway-deflector combination which gives the arrangement its specific nature.

The invention, of course, is in no way limited to the embodiments represented and described which were given only by way of example.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

1 In a. ship funnel which has a vertical lon gitudinal plane of symmetry, in combination: several substantially vertical pipes for smoke, steam and other gases, said pipes which are open at their upper ends, having their axes substantially in said plane, a streamlined unperforated envelope surrounding said pipes over a certain length and substantially from the upper ends of said pipes, two side screens of a generally longitudinal direction spaced laterally from said envelope and providing with said envelope two lateral substantially longitudinal passageways open ahead of the front end and aft of the rear end of said envelope to canalize the outside air, and at least one transversal deflector in each passageway between said envelope and the corresponding screen, said deflector having a front face and a rear face which diverge downwardly from one another to deflect in an ascending direction the air which flows through said passageway respectively from the front to the rear and inversely.

2. In a ship funnel which has a vertical longitudinal plane of symmetry, in combination: several substantially vertical pipes for smoke, steam and other gases, said pipes which are open at their upper ends having their axes substantially in said plane, a streamlined unperforated envelope surrounding said pipes over a certain length and substantially from the upper ends of said pipes, said envelope having a longitudinal horizontal length which is substantially equal to six times its maximum width and said maximum width occurring at about one third of said ength from the front end of the envelope and the height of said envelope being substantially equal to half said length, a convex upper closing dome which is connected to the upper edge of said envelope and through which said pipes protrude slightly, two side screens of a generally longitudinal direction spaced laterally from said envelope and providing with said envelope two lateral substantially longitudinal passageways open ahead of the front end and aft of the rear end of said envelope to canalize the outside air, and at least one deflector in each passageway between said envelope and the corresponding screen, said deflector having a front face and a rear face which diverge downwardly from one another to deflect in an ascending direction the air which flows through said passageway respectively from the front to the rear and inversely, each of said screens being so assembled to said envelope that taking in account the volume of said deflector, the section of each passageway, from front to rear, first decreases, then increases.

3. A ship funnel as claimed in claim 2 wherein said dome protrudes in front with respect to said streamlined envelope and a concave surface is provided which connects the front edge of said dome to said envelope to facilitate the flow of the air impinging on the front of said envelope.

4. In a ship funnel adapted to be secured to the deck of the ship and having a vertical longitudinal plane of symmetry, in combination: several substantially vertical pipes for smoke, steam and other gases, said pipes being open at their upper ends and having their axes substantially in said plane, a lower casing which surrounds said pipes and is adapted to be secured to said deck of the ship, a substantially horizontal platform connected to the upper edge of said casing and perforated for the passage of said pipes, a streamlined envelope surrounding said pipes between said platform and substantially the upper ends of said pipes, a convex upper closing dome which is connected to the upper edge of said streamlined envelope and through which said pipes protrude slightly, two side screens of a generally longitudinal direction spaced laterally from said streamlined envelope extending upwards said casing having their upper edges substantially at the level of the upper edge of said streamlined envelope and providing with said envelope two lateral substantially longitudinal passageways open ahead of the front end and aft of the rear end of said envelope to canalize the outside air, each of said screens being so assembled to said envelope that taking in account the volume of deflecting device, the section of each passageway, from front to rear, first decreases, then increases; two deflecting walls connected to said upper edges of said screens and inclined towards the vertical longitudinal plane of symmetry of the funnel, at least one deflector element arranged in each passageway between said envelope and the corresponding screen, said 9 deflector having a front face and a rear face which diverge downwardly from one another to deflect in an ascending direction the air which flows through said passageway, from the front to the rear and/or inversely.

5. A ship funnel as claimed in claim 4 further comprising deflecting walls secured to the front and rear ends of said screens, said walls diverging from one another, from their lines of junction with said screens, so as to direct the air impinging on said walls towards said passageways.

6. A ship funnel as claimed in claim 5, wherein said deflecting walls have downwardly extended portions below said platform along said casing, the front and rear ends of said platform being obliquely disposed and sloping downward from the line of junction of the plane intermediate portion of said platform in order to increase the end apertures of said passageways in combination with said downwardly extended portions of said deflecting walls.

7. A ship funnel as claimed in claim 4 wherein said deflector has a substantially triangular shape and is spaced from said platform so as to form a sort of nozzle with it.

8. A ship funnel as claimed in claim 7, wherein said deflector has a substantially plane base which is parallel to said platform, whilst the two other faces of said deflecting element are inclined in the longitudinal and transverse directions of the funnel, said faces sloping downward from the corresponding side screen towards the streamlined envelope.

9. A ship funnel as claimed in claim 4 wherein said deflector element has a base spaced apart from said platform whilst the two other faces of said element are helical.

10. A ship funnel as claimed in claim 4 wheresaid deflector is concave towards the front,

10 convex towards the rear and on the lower face, the rear portion of said platform rising from front to rear.

11. A ship funnel as claimed in claim 4 wherein at least one deflecting surface is disposed in front of said deflector between said envelope and the corresponding side screen.

12. A ship funnel as claimed in claim 4 wherein said platform has an aperture in each of said passageways and said deflector is formed of a front wall and a rear wall, said walls being obliquely disposed so that they diverge downward from one another being connected by their lower edges with the rear and front edges of said aperture.

13. A ship funnel as claimed in claim 12 wherein one of said two obliquely disposed walls of said deflector is provided with at least one aperture, said funnel further comprising a vane adjustable in position for the ventilation of a part of said ship through said aperture of said platform and means for controlling said vane.

14. A ship funnel, as claimed in claim 1 wherein each of said screen has at least one side aperture and an adjustable vane is provided on said aperture.

EMILE FREDERIC JOSEPH LASCROUX.

References Cited in the flle of this patent UNITED STATES PATENTS Number Name Date 2,601,663 Lamb June 24, 1952 2,610,570 Valensi Sept. 16, 1952 FOREIGN PATENTS Number Country Date 21,618 Great Britain of 1903 519,114 Germany Feb. 5, 1931 I 949503 France 1 Sept. 1, 1949

Images